From 12bb80617830693e2bc3d2d68ba89f404b3f82d4 Mon Sep 17 00:00:00 2001
From: Lioncash <mathew1800@gmail.com>
Date: Mon, 26 Oct 2020 18:41:05 -0400
Subject: [PATCH] Externals: Update fmt to 7.1.0

Updates fmt to the latest release from 6.1.2
---
 Externals/fmt/.gitignore                      |   34 -
 Externals/fmt/CMakeLists.txt                  |  146 +-
 Externals/fmt/CONTRIBUTING.md                 |    3 +
 Externals/fmt/ChangeLog.rst                   |  960 ++++-
 Externals/fmt/README.rst                      |  401 +-
 Externals/fmt/include/fmt/chrono.h            |  250 +-
 Externals/fmt/include/fmt/color.h             |  130 +-
 Externals/fmt/include/fmt/compile.h           |  323 +-
 Externals/fmt/include/fmt/core.h              | 1521 +++++---
 Externals/fmt/include/fmt/format-inl.h        | 2249 ++++++++---
 Externals/fmt/include/fmt/format.h            | 3279 ++++++++++-------
 Externals/fmt/include/fmt/locale.h            |   59 +-
 Externals/fmt/include/fmt/os.h                |  480 +++
 Externals/fmt/include/fmt/ostream.h           |   76 +-
 Externals/fmt/include/fmt/posix.h             |  323 +-
 Externals/fmt/include/fmt/printf.h            |  200 +-
 Externals/fmt/include/fmt/ranges.h            |  112 +-
 Externals/fmt/src/format.cc                   |  167 +-
 Externals/fmt/src/{posix.cc => os.cc}         |  169 +-
 Externals/fmt/support/README                  |    2 -
 Externals/fmt/support/Vagrantfile             |    1 +
 Externals/fmt/support/cmake/JoinPaths.cmake   |   26 +
 Externals/fmt/support/cmake/cxx14.cmake       |   11 -
 Externals/fmt/support/cmake/fmt.pc.in         |    6 +-
 Externals/fmt/support/fmt.pro                 |   27 -
 Externals/fmt/support/manage.py               |   31 +-
 .../fmt/support/update-coverity-branch.py     |   30 -
 27 files changed, 7388 insertions(+), 3628 deletions(-)
 delete mode 100755 Externals/fmt/.gitignore
 create mode 100644 Externals/fmt/include/fmt/os.h
 rename Externals/fmt/src/{posix.cc => os.cc} (63%)
 mode change 100755 => 100644
 create mode 100644 Externals/fmt/support/cmake/JoinPaths.cmake
 delete mode 100755 Externals/fmt/support/fmt.pro
 delete mode 100755 Externals/fmt/support/update-coverity-branch.py

diff --git a/Externals/fmt/.gitignore b/Externals/fmt/.gitignore
deleted file mode 100755
index 694f8f8f2bf3..000000000000
--- a/Externals/fmt/.gitignore
+++ /dev/null
@@ -1,34 +0,0 @@
-.vscode/
-
-*.iml
-.idea/
-.externalNativeBuild/
-.gradle/
-gradle/
-gradlew*
-local.properties
-build/
-
-bin/
-/_CPack_Packages
-/CMakeScripts
-/doc/doxyxml
-/doc/html
-virtualenv
-/Testing
-/install_manifest.txt
-*~
-*.a
-*.so*
-*.xcodeproj
-*.zip
-cmake_install.cmake
-CPack*.cmake
-fmt-*.cmake
-CTestTestfile.cmake
-CMakeCache.txt
-CMakeFiles
-FMT.build
-Makefile
-run-msbuild.bat
-fmt.pc
diff --git a/Externals/fmt/CMakeLists.txt b/Externals/fmt/CMakeLists.txt
index 3b6b79ef9b9c..f21cf4561ee5 100755
--- a/Externals/fmt/CMakeLists.txt
+++ b/Externals/fmt/CMakeLists.txt
@@ -1,10 +1,8 @@
-cmake_minimum_required(VERSION 3.1.0)
+cmake_minimum_required(VERSION 3.1...3.18)
 
-# Use newer policies if available, up to most recent tested version of CMake.
-if(${CMAKE_VERSION} VERSION_LESS 3.11)
+# Fallback for using newer policies on CMake <3.12.
+if(${CMAKE_VERSION} VERSION_LESS 3.12)
   cmake_policy(VERSION ${CMAKE_MAJOR_VERSION}.${CMAKE_MINOR_VERSION})
-else()
-  cmake_policy(VERSION 3.11)
 endif()
 
 # Determine if fmt is built as a subproject (using add_subdirectory)
@@ -24,15 +22,40 @@ function(join result_var)
   set(${result_var} "${result}" PARENT_SCOPE)
 endfunction()
 
+include(CMakeParseArguments)
+
+# Sets a cache variable with a docstring joined from multiple arguments:
+#   set(<variable> <value>... CACHE <type> <docstring>...)
+# This allows splitting a long docstring for readability.
+function(set_verbose)
+  # cmake_parse_arguments is broken in CMake 3.4 (cannot parse CACHE) so use
+  # list instead.
+  list(GET ARGN 0 var)
+  list(REMOVE_AT ARGN 0)
+  list(GET ARGN 0 val)
+  list(REMOVE_AT ARGN 0)
+  list(REMOVE_AT ARGN 0)
+  list(GET ARGN 0 type)
+  list(REMOVE_AT ARGN 0)
+  join(doc ${ARGN})
+  set(${var} ${val} CACHE ${type} ${doc})
+endfunction()
+
 # Set the default CMAKE_BUILD_TYPE to Release.
 # This should be done before the project command since the latter can set
 # CMAKE_BUILD_TYPE itself (it does so for nmake).
 if (MASTER_PROJECT AND NOT CMAKE_BUILD_TYPE)
-  join(doc "Choose the type of build, options are: None(CMAKE_CXX_FLAGS or "
-           "CMAKE_C_FLAGS used) Debug Release RelWithDebInfo MinSizeRel.")
-  set(CMAKE_BUILD_TYPE Release CACHE STRING ${doc})
+  set_verbose(CMAKE_BUILD_TYPE Release CACHE STRING
+              "Choose the type of build, options are: None(CMAKE_CXX_FLAGS or "
+              "CMAKE_C_FLAGS used) Debug Release RelWithDebInfo MinSizeRel.")
 endif ()
 
+project(FMT CXX)
+include(GNUInstallDirs)
+set_verbose(FMT_INC_DIR ${CMAKE_INSTALL_INCLUDEDIR} CACHE STRING
+            "Installation directory for include files, a relative path that "
+            "will be joined with ${CMAKE_INSTALL_PREFIX} or an absolute path.")
+
 option(FMT_PEDANTIC "Enable extra warnings and expensive tests." OFF)
 option(FMT_WERROR "Halt the compilation with an error on compiler warnings."
        OFF)
@@ -43,8 +66,7 @@ option(FMT_INSTALL "Generate the install target." ${MASTER_PROJECT})
 option(FMT_TEST "Generate the test target." ${MASTER_PROJECT})
 option(FMT_FUZZ "Generate the fuzz target." OFF)
 option(FMT_CUDA_TEST "Generate the cuda-test target." OFF)
-
-project(FMT CXX)
+option(FMT_OS "Include core requiring OS (Windows/Posix) " ON)
 
 # Get version from core.h
 file(READ include/fmt/core.h core_h)
@@ -61,26 +83,35 @@ message(STATUS "Version: ${FMT_VERSION}")
 
 message(STATUS "Build type: ${CMAKE_BUILD_TYPE}")
 
-set(CMAKE_RUNTIME_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/bin)
+if (NOT CMAKE_RUNTIME_OUTPUT_DIRECTORY)
+  set(CMAKE_RUNTIME_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/bin)
+endif ()
 
 set(CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH}
   "${CMAKE_CURRENT_SOURCE_DIR}/support/cmake")
 
 include(cxx14)
 include(CheckCXXCompilerFlag)
+include(JoinPaths)
 
-set(FMT_REQUIRED_FEATURES cxx_auto_type cxx_variadic_templates)
+list(FIND CMAKE_CXX_COMPILE_FEATURES "cxx_variadic_templates" index)
+if (${index} GREATER -1)
+  # Use cxx_variadic_templates instead of more appropriate cxx_std_11 for
+  # compatibility with older CMake versions.
+  set(FMT_REQUIRED_FEATURES cxx_variadic_templates)
+endif ()
+message(STATUS "Required features: ${FMT_REQUIRED_FEATURES}")
 
 if (CMAKE_CXX_COMPILER_ID MATCHES "GNU")
   set(PEDANTIC_COMPILE_FLAGS -pedantic-errors -Wall -Wextra -pedantic
       -Wold-style-cast -Wundef
       -Wredundant-decls -Wwrite-strings -Wpointer-arith
       -Wcast-qual -Wformat=2 -Wmissing-include-dirs
-      -Wcast-align -Wnon-virtual-dtor
+      -Wcast-align
       -Wctor-dtor-privacy -Wdisabled-optimization
       -Winvalid-pch -Woverloaded-virtual
-      -Wconversion -Wswitch-enum
-      -Wno-ctor-dtor-privacy -Wno-format-nonliteral -Wno-shadow)
+      -Wconversion -Wswitch-enum -Wundef
+      -Wno-ctor-dtor-privacy -Wno-format-nonliteral)
   if (NOT CMAKE_CXX_COMPILER_VERSION VERSION_LESS 4.6)
       set(PEDANTIC_COMPILE_FLAGS ${PEDANTIC_COMPILE_FLAGS} -Wnoexcept
          -Wno-dangling-else -Wno-unused-local-typedefs)
@@ -98,8 +129,8 @@ if (CMAKE_CXX_COMPILER_ID MATCHES "GNU")
 endif ()
 
 if (CMAKE_CXX_COMPILER_ID MATCHES "Clang")
-  set(PEDANTIC_COMPILE_FLAGS -Wall -Wextra -pedantic -Wconversion
-      -Wno-sign-conversion -Wdeprecated -Wweak-vtables)
+  set(PEDANTIC_COMPILE_FLAGS -Wall -Wextra -pedantic -Wconversion -Wundef
+      -Wdeprecated -Wweak-vtables)
   check_cxx_compiler_flag(-Wzero-as-null-pointer-constant HAS_NULLPTR_WARNING)
   if (HAS_NULLPTR_WARNING)
     set(PEDANTIC_COMPILE_FLAGS ${PEDANTIC_COMPILE_FLAGS}
@@ -123,7 +154,9 @@ if (MASTER_PROJECT AND CMAKE_GENERATOR MATCHES "Visual Studio")
     set(MSBUILD_SETUP "call \"${WINSDK_SETENV}\"")
   endif ()
   # Set FrameworkPathOverride to get rid of MSB3644 warnings.
-  set(netfxpath "C:\\Program Files\\Reference Assemblies\\Microsoft\\Framework\\.NETFramework\\v4.0")
+  join(netfxpath
+       "C:\\Program Files\\Reference Assemblies\\Microsoft\\Framework\\"
+       ".NETFramework\\v4.0")
   file(WRITE run-msbuild.bat "
     ${MSBUILD_SETUP}
     ${CMAKE_MAKE_PROGRAM} -p:FrameworkPathOverride=\"${netfxpath}\" %*")
@@ -151,8 +184,12 @@ endfunction()
 
 # Define the fmt library, its includes and the needed defines.
 add_headers(FMT_HEADERS chrono.h color.h compile.h core.h format.h format-inl.h
-                        locale.h ostream.h posix.h printf.h ranges.h)
-set(FMT_SOURCES src/format.cc src/posix.cc)
+                        locale.h os.h ostream.h posix.h printf.h ranges.h)
+if (FMT_OS)
+  set(FMT_SOURCES src/format.cc src/os.cc)
+else()
+  set(FMT_SOURCES src/format.cc)
+endif ()
 
 add_library(fmt ${FMT_SOURCES} ${FMT_HEADERS} README.rst ChangeLog.rst)
 add_library(fmt::fmt ALIAS fmt)
@@ -161,6 +198,13 @@ if (HAVE_STRTOD_L)
   target_compile_definitions(fmt PUBLIC FMT_LOCALE)
 endif ()
 
+if (MINGW)
+  check_cxx_compiler_flag("Wa,-mbig-obj" FMT_HAS_MBIG_OBJ)
+  if (${FMT_HAS_MBIG_OBJ})
+    target_compile_options(fmt PUBLIC "-Wa,-mbig-obj")
+  endif()
+endif ()
+
 if (FMT_WERROR)
   target_compile_options(fmt PRIVATE ${WERROR_FLAG})
 endif ()
@@ -172,14 +216,24 @@ target_compile_features(fmt INTERFACE ${FMT_REQUIRED_FEATURES})
 
 target_include_directories(fmt PUBLIC
   $<BUILD_INTERFACE:${PROJECT_SOURCE_DIR}/include>
-  $<INSTALL_INTERFACE:include>)
+  $<INSTALL_INTERFACE:${FMT_INC_DIR}>)
+
+set(FMT_DEBUG_POSTFIX d CACHE STRING "Debug library postfix.")
 
 set_target_properties(fmt PROPERTIES
   VERSION ${FMT_VERSION} SOVERSION ${CPACK_PACKAGE_VERSION_MAJOR}
-  DEBUG_POSTFIX d)
+  DEBUG_POSTFIX "${FMT_DEBUG_POSTFIX}")
+
+# Set FMT_LIB_NAME for pkg-config fmt.pc. We cannot use the OUTPUT_NAME target
+# property because it's not set by default.
+set(FMT_LIB_NAME fmt)
+if (CMAKE_BUILD_TYPE STREQUAL "Debug")
+  set(FMT_LIB_NAME ${FMT_LIB_NAME}${FMT_DEBUG_POSTFIX})
+endif ()
 
 if (BUILD_SHARED_LIBS)
-  if (UNIX AND NOT APPLE AND NOT ${CMAKE_SYSTEM_NAME} MATCHES "SunOS")
+  if (UNIX AND NOT APPLE AND NOT ${CMAKE_SYSTEM_NAME} MATCHES "SunOS" AND
+      NOT EMSCRIPTEN)
     # Fix rpmlint warning:
     # unused-direct-shlib-dependency /usr/lib/libformat.so.1.1.0 /lib/libm.so.6.
     target_link_libraries(fmt -Wl,--as-needed)
@@ -194,43 +248,42 @@ add_library(fmt-header-only INTERFACE)
 add_library(fmt::fmt-header-only ALIAS fmt-header-only)
 
 target_compile_definitions(fmt-header-only INTERFACE FMT_HEADER_ONLY=1)
-
 target_compile_features(fmt-header-only INTERFACE ${FMT_REQUIRED_FEATURES})
 
 target_include_directories(fmt-header-only INTERFACE
   $<BUILD_INTERFACE:${PROJECT_SOURCE_DIR}/include>
-  $<INSTALL_INTERFACE:include>)
+  $<INSTALL_INTERFACE:${FMT_INC_DIR}>)
 
 # Install targets.
 if (FMT_INSTALL)
-  include(GNUInstallDirs)
   include(CMakePackageConfigHelpers)
-  set(FMT_CMAKE_DIR ${CMAKE_INSTALL_LIBDIR}/cmake/fmt CACHE STRING
-      "Installation directory for cmake files, relative to ${CMAKE_INSTALL_PREFIX}.")
+  set_verbose(FMT_CMAKE_DIR ${CMAKE_INSTALL_LIBDIR}/cmake/fmt CACHE STRING
+              "Installation directory for cmake files, a relative path that "
+              "will be joined with ${CMAKE_INSTALL_PREFIX} or an absolute "
+              "path.")
   set(version_config ${PROJECT_BINARY_DIR}/fmt-config-version.cmake)
   set(project_config ${PROJECT_BINARY_DIR}/fmt-config.cmake)
   set(pkgconfig ${PROJECT_BINARY_DIR}/fmt.pc)
   set(targets_export_name fmt-targets)
 
-  set (INSTALL_TARGETS fmt)
-  if (TARGET fmt-header-only)
-    set(INSTALL_TARGETS ${INSTALL_TARGETS} fmt-header-only)
-  endif ()
-
-  set(FMT_LIB_DIR ${CMAKE_INSTALL_LIBDIR} CACHE STRING
-      "Installation directory for libraries, relative to ${CMAKE_INSTALL_PREFIX}.")
-
-  set(FMT_INC_DIR ${CMAKE_INSTALL_INCLUDEDIR}/fmt CACHE STRING
-      "Installation directory for include files, relative to ${CMAKE_INSTALL_PREFIX}.")
+  set_verbose(FMT_LIB_DIR ${CMAKE_INSTALL_LIBDIR} CACHE STRING
+              "Installation directory for libraries, a relative path that "
+              "will be joined to ${CMAKE_INSTALL_PREFIX} or an absolute path.")
 
-  set(FMT_PKGCONFIG_DIR ${CMAKE_INSTALL_LIBDIR}/pkgconfig CACHE PATH
-      "Installation directory for pkgconfig (.pc) files, relative to ${CMAKE_INSTALL_PREFIX}.")
+  set_verbose(FMT_PKGCONFIG_DIR ${CMAKE_INSTALL_LIBDIR}/pkgconfig CACHE PATH
+              "Installation directory for pkgconfig (.pc) files, a relative "
+              "path that will be joined with ${CMAKE_INSTALL_PREFIX} or an "
+              "absolute path.")
 
   # Generate the version, config and target files into the build directory.
   write_basic_package_version_file(
     ${version_config}
     VERSION ${FMT_VERSION}
     COMPATIBILITY AnyNewerVersion)
+
+  join_paths(libdir_for_pc_file "\${exec_prefix}" "${FMT_LIB_DIR}")
+  join_paths(includedir_for_pc_file "\${prefix}" "${FMT_INC_DIR}")
+
   configure_file(
     "${PROJECT_SOURCE_DIR}/support/cmake/fmt.pc.in"
     "${pkgconfig}"
@@ -239,6 +292,8 @@ if (FMT_INSTALL)
     ${PROJECT_SOURCE_DIR}/support/cmake/fmt-config.cmake.in
     ${project_config}
     INSTALL_DESTINATION ${FMT_CMAKE_DIR})
+
+  set(INSTALL_TARGETS fmt fmt-header-only)
   # Use a namespace because CMake provides better diagnostics for namespaced
   # imported targets.
   export(TARGETS ${INSTALL_TARGETS} NAMESPACE fmt::
@@ -259,7 +314,7 @@ if (FMT_INSTALL)
 
   install(FILES $<TARGET_PDB_FILE:${INSTALL_TARGETS}>
           DESTINATION ${FMT_LIB_DIR} OPTIONAL)
-  install(FILES ${FMT_HEADERS} DESTINATION ${FMT_INC_DIR})
+  install(FILES ${FMT_HEADERS} DESTINATION "${FMT_INC_DIR}/fmt")
   install(FILES "${pkgconfig}" DESTINATION "${FMT_PKGCONFIG_DIR}")
 endif ()
 
@@ -275,13 +330,20 @@ endif ()
 # Control fuzzing independent of the unit tests.
 if (FMT_FUZZ)
   add_subdirectory(test/fuzzing)
+
+  # The FMT_FUZZ macro is used to prevent resource exhaustion in fuzzing
+  # mode and make fuzzing practically possible. It is similar to
+  # FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION but uses a different name to
+  # avoid interfering with fuzzing of projects that use {fmt}.
+  # See also https://llvm.org/docs/LibFuzzer.html#fuzzer-friendly-build-mode.
+  target_compile_definitions(fmt PUBLIC FMT_FUZZ)
 endif ()
 
 set(gitignore ${PROJECT_SOURCE_DIR}/.gitignore)
 if (MASTER_PROJECT AND EXISTS ${gitignore})
   # Get the list of ignored files from .gitignore.
   file (STRINGS ${gitignore} lines)
-  LIST(REMOVE_ITEM lines /doc/html)
+  list(REMOVE_ITEM lines /doc/html)
   foreach (line ${lines})
     string(REPLACE "." "[.]" line "${line}")
     string(REPLACE "*" ".*" line "${line}")
diff --git a/Externals/fmt/CONTRIBUTING.md b/Externals/fmt/CONTRIBUTING.md
index 3532bd11e4bd..b82f145069a8 100644
--- a/Externals/fmt/CONTRIBUTING.md
+++ b/Externals/fmt/CONTRIBUTING.md
@@ -14,4 +14,7 @@ exceptions:
 * snake_case should be used instead of UpperCamelCase for function and type
   names
 
+All documentation must adhere to the [Google Developer Documentation Style
+Guide](https://developers.google.com/style).
+
 Thanks for contributing!
diff --git a/Externals/fmt/ChangeLog.rst b/Externals/fmt/ChangeLog.rst
index 75a009e4c653..f9a2d8ebbec0 100755
--- a/Externals/fmt/ChangeLog.rst
+++ b/Externals/fmt/ChangeLog.rst
@@ -1,3 +1,941 @@
+7.1.0 - 2020-10-25
+------------------
+
+* Switched from `Grisu3
+  <https://www.cs.tufts.edu/~nr/cs257/archive/florian-loitsch/printf.pdf>`_
+  to `Dragonbox <https://github.com/jk-jeon/dragonbox>`_ for the default
+  floating-point formatting which gives the shortest decimal representation
+  with round-trip guarantee and correct rounding
+  (`#1882 <https://github.com/fmtlib/fmt/pull/1882>`_,
+  `#1887 <https://github.com/fmtlib/fmt/pull/1887>`_,
+  `#1894 <https://github.com/fmtlib/fmt/pull/1894>`_). This makes {fmt} up to
+  20-30x faster than common implementations of ``std::ostringstream`` and
+  ``sprintf`` on `dtoa-benchmark <https://github.com/fmtlib/dtoa-benchmark>`_
+  and faster than double-conversion and Ryū:
+
+  .. image:: https://user-images.githubusercontent.com/576385/
+             95684665-11719600-0ba8-11eb-8e5b-972ff4e49428.png
+
+  It is possible to get even better performance at the cost of larger binary
+  size by compiling with the ``FMT_USE_FULL_CACHE_DRAGONBOX`` macro set to 1.
+
+  Thanks `@jk-jeon (Junekey Jeon) <https://github.com/jk-jeon>`_.
+
+* Added an experimental unsynchronized file output API which, together with
+  `format string compilation <https://fmt.dev/latest/api.html#compile-api>`_,
+  can give `5-9 times speed up compared to fprintf
+  <https://www.zverovich.net/2020/08/04/optimal-file-buffer-size.html>`_
+  on common platforms (`godbolt <https://godbolt.org/z/nsTcG8>`__):
+
+  .. code:: c++
+
+     #include <fmt/os.h>
+
+     int main() {
+       auto f = fmt::output_file("guide");
+       f.print("The answer is {}.", 42);
+     }
+
+* Added a formatter for ``std::chrono::time_point<system_clock>``
+  (`#1819 <https://github.com/fmtlib/fmt/issues/1819>`_,
+  `#1837 <https://github.com/fmtlib/fmt/pull/1837>`_). For example
+  (`godbolt <https://godbolt.org/z/c4M6fh>`__):
+
+  .. code:: c++
+
+     #include <fmt/chrono.h>
+
+     int main() {
+       auto now = std::chrono::system_clock::now();
+       fmt::print("The time is {:%H:%M:%S}.\n", now);
+     }
+
+  Thanks `@adamburgess (Adam Burgess) <https://github.com/adamburgess>`_.
+
+* Added support for ranges with non-const ``begin``/``end`` to ``fmt::join``
+  (`#1784 <https://github.com/fmtlib/fmt/issues/1784>`_,
+  `#1786 <https://github.com/fmtlib/fmt/pull/1786>`_). For example
+  (`godbolt <https://godbolt.org/z/jP63Tv>`__):
+
+  .. code:: c++
+
+     #include <fmt/ranges.h>
+     #include <range/v3/view/filter.hpp>
+
+     int main() {
+       using std::literals::string_literals::operator""s;
+       auto strs = std::array{"a"s, "bb"s, "ccc"s};
+       auto range = strs | ranges::views::filter(
+         [] (const std::string &x) { return x.size() != 2; }
+       );
+       fmt::print("{}\n", fmt::join(range, ""));
+     }
+
+  prints "accc".
+
+  Thanks `@tonyelewis (Tony E Lewis) <https://github.com/tonyelewis>`_.
+
+* Added a ``memory_buffer::append`` overload that takes a range
+  (`#1806 <https://github.com/fmtlib/fmt/pull/1806>`_).
+  Thanks `@BRevzin (Barry Revzin) <https://github.com/BRevzin>`_.
+
+* Improved handling of single code units in ``FMT_COMPILE``. For example:
+
+  .. code:: c++
+
+     #include <fmt/compile.h>
+
+     char* f(char* buf) {
+       return fmt::format_to(buf, FMT_COMPILE("x{}"), 42);
+     }
+
+  compiles to just (`godbolt <https://godbolt.org/z/5vncz3>`__):
+
+  .. code:: asm
+
+     _Z1fPc:
+       movb $120, (%rdi)
+       xorl %edx, %edx
+       cmpl $42, _ZN3fmt2v76detail10basic_dataIvE23zero_or_powers_of_10_32E+8(%rip)
+       movl $3, %eax
+       seta %dl
+       subl %edx, %eax
+       movzwl _ZN3fmt2v76detail10basic_dataIvE6digitsE+84(%rip), %edx
+       cltq
+       addq %rdi, %rax
+       movw %dx, -2(%rax)
+       ret
+
+  Here a single ``mov`` instruction writes ``'x'`` (``$120``) to the output
+  buffer.
+
+* Added dynamic width support to format string compilation
+  (`#1809 <https://github.com/fmtlib/fmt/issues/1809>`_).
+
+* Improved error reporting for unformattable types: now you'll get the type name
+  directly in the error message instead of the note:
+
+  .. code:: c++
+
+     #include <fmt/core.h>
+
+     struct how_about_no {};
+
+     int main() {
+       fmt::print("{}", how_about_no());
+     }
+
+  Error (`godbolt <https://godbolt.org/z/GoxM4e>`__):
+
+  ``fmt/core.h:1438:3: error: static_assert failed due to requirement
+  'fmt::v7::formattable<how_about_no>()' "Cannot format an argument.
+  To make type T formattable provide a formatter<T> specialization:
+  https://fmt.dev/latest/api.html#udt"
+  ...``
+
+* Added the `make_args_checked <https://fmt.dev/7.1.0/api.html#argument-lists>`_
+  function template that allows you to write formatting functions with
+  compile-time format string checks and avoid binary code bloat
+  (`godbolt <https://godbolt.org/z/PEf9qr>`__):
+
+  .. code:: c++
+
+     void vlog(const char* file, int line, fmt::string_view format,
+               fmt::format_args args) {
+       fmt::print("{}: {}: ", file, line);
+       fmt::vprint(format, args);
+     }
+
+     template <typename S, typename... Args>
+     void log(const char* file, int line, const S& format, Args&&... args) {
+       vlog(file, line, format,
+           fmt::make_args_checked<Args...>(format, args...));
+     }
+
+     #define MY_LOG(format, ...) \
+       log(__FILE__, __LINE__, FMT_STRING(format), __VA_ARGS__)
+
+     MY_LOG("invalid squishiness: {}", 42);
+
+* Replaced ``snprintf`` fallback with a faster internal IEEE 754 ``float`` and
+  ``double`` formatter for arbitrary precision. For example
+  (`godbolt <https://godbolt.org/z/dPhWvj>`__):
+
+  .. code:: c++
+
+     #include <fmt/core.h>
+
+     int main() {
+       fmt::print("{:.500}\n", 4.9406564584124654E-324);
+     }
+
+  prints
+
+  ``4.9406564584124654417656879286822137236505980261432476442558568250067550727020875186529983636163599237979656469544571773092665671035593979639877479601078187812630071319031140452784581716784898210368871863605699873072305000638740915356498438731247339727316961514003171538539807412623856559117102665855668676818703956031062493194527159149245532930545654440112748012970999954193198940908041656332452475714786901472678015935523861155013480352649347201937902681071074917033322268447533357208324319360923829e-324``.
+
+* Made ``format_to_n`` and ``formatted_size`` part of the `core API
+  <https://fmt.dev/latest/api.html#core-api>`__
+  (`godbolt <https://godbolt.org/z/sPjY1K>`__):
+
+  .. code:: c++
+
+     #include <fmt/core.h>
+
+     int main() {
+       char buffer[10];
+       auto result = fmt::format_to_n(buffer, sizeof(buffer), "{}", 42);
+     }
+
+* Added ``fmt::format_to_n`` overload with format string compilation
+  (`#1764 <https://github.com/fmtlib/fmt/issues/1764>`_,
+  `#1767 <https://github.com/fmtlib/fmt/pull/1767>`_,
+  `#1869 <https://github.com/fmtlib/fmt/pull/1869>`_). For example
+  (`godbolt <https://godbolt.org/z/93h86q>`__):
+
+  .. code:: c++
+
+     #include <fmt/compile.h>
+
+     int main() {
+       char buffer[8];
+       fmt::format_to_n(buffer, sizeof(buffer), FMT_COMPILE("{}"), 42);
+     }
+
+  Thanks `@Kurkin (Dmitry Kurkin) <https://github.com/Kurkin>`_,
+  `@alexezeder (Alexey Ochapov) <https://github.com/alexezeder>`_.
+
+* Added ``fmt::format_to`` overload that take ``text_style``
+  (`#1593 <https://github.com/fmtlib/fmt/issues/1593>`_,
+  `#1842 <https://github.com/fmtlib/fmt/issues/1842>`_,
+  `#1843 <https://github.com/fmtlib/fmt/pull/1843>`_). For example
+  (`godbolt <https://godbolt.org/z/91153r>`__):
+
+  .. code:: c++
+
+     #include <fmt/color.h>
+
+     int main() {
+       std::string out;
+       fmt::format_to(std::back_inserter(out),
+                      fmt::emphasis::bold | fg(fmt::color::red),
+                      "The answer is {}.", 42);
+     }
+
+  Thanks `@Naios (Denis Blank) <https://github.com/Naios>`_.
+
+* Made the ``#`` specifier emit trailing zeros in addition to the decimal point
+  (`#1797 <https://github.com/fmtlib/fmt/issues/1797>`_). For example
+  (`godbolt <https://godbolt.org/z/bhdcW9>`__):
+
+  .. code:: c++
+
+     #include <fmt/core.h>
+
+     int main() {
+       fmt::print("{:#.2g}", 0.5);
+     }
+
+  prints ``0.50``.
+
+* Changed the default floating point format to not include ``.0`` for
+  consistency with ``std::format`` and ``std::to_chars``
+  (`#1893 <https://github.com/fmtlib/fmt/issues/1893>`_,
+  `#1943 <https://github.com/fmtlib/fmt/issues/1943>`_). It is possible to get
+  the decimal point and trailing zero with the ``#`` specifier.
+
+* Fixed an issue with floating-point formatting that could result in addition of
+  a non-significant trailing zero in rare cases e.g. ``1.00e-34`` instead of
+  ``1.0e-34`` (`#1873 <https://github.com/fmtlib/fmt/issues/1873>`_,
+  `#1917 <https://github.com/fmtlib/fmt/issues/1917>`_).
+
+* Made ``fmt::to_string`` fallback on ``ostream`` insertion operator if
+  the ``formatter`` specialization is not provided
+  (`#1815 <https://github.com/fmtlib/fmt/issues/1815>`_,
+  `#1829 <https://github.com/fmtlib/fmt/pull/1829>`_).
+  Thanks `@alexezeder (Alexey Ochapov) <https://github.com/alexezeder>`_.
+
+* Added support for the append mode to the experimental file API and
+  improved ``fcntl.h`` detection.
+  (`#1847 <https://github.com/fmtlib/fmt/pull/1847>`_,
+  `#1848 <https://github.com/fmtlib/fmt/pull/1848>`_).
+  Thanks `@t-wiser <https://github.com/t-wiser>`_.
+
+* Fixed handling of types that have both an implicit conversion operator and
+  an overloaded ``ostream`` insertion operator
+  (`#1766 <https://github.com/fmtlib/fmt/issues/1766>`_).
+
+* Fixed a slicing issue in an internal iterator type
+  (`#1822 <https://github.com/fmtlib/fmt/pull/1822>`_).
+  Thanks `@BRevzin (Barry Revzin) <https://github.com/BRevzin>`_.
+
+* Fixed an issue in locale-specific integer formatting
+  (`#1927 <https://github.com/fmtlib/fmt/issues/1927>`_).
+
+* Fixed handling of exotic code unit types
+  (`#1870 <https://github.com/fmtlib/fmt/issues/1870>`_,
+  `#1932 <https://github.com/fmtlib/fmt/issues/1932>`_).
+
+* Improved ``FMT_ALWAYS_INLINE``
+  (`#1878 <https://github.com/fmtlib/fmt/pull/1878>`_).
+  Thanks `@jk-jeon (Junekey Jeon) <https://github.com/jk-jeon>`_.
+
+* Removed dependency on ``windows.h``
+  (`#1900 <https://github.com/fmtlib/fmt/pull/1900>`_).
+  Thanks `@bernd5 (Bernd Baumanns) <https://github.com/bernd5>`_.
+
+* Optimized counting of decimal digits on MSVC
+  (`#1890 <https://github.com/fmtlib/fmt/pull/1890>`_).
+  Thanks `@mwinterb <https://github.com/mwinterb>`_.
+
+* Improved documentation
+  (`#1772 <https://github.com/fmtlib/fmt/issues/1772>`_,
+  `#1775 <https://github.com/fmtlib/fmt/pull/1775>`_,
+  `#1792 <https://github.com/fmtlib/fmt/pull/1792>`_,
+  `#1838 <https://github.com/fmtlib/fmt/pull/1838>`_,
+  `#1888 <https://github.com/fmtlib/fmt/pull/1888>`_,
+  `#1918 <https://github.com/fmtlib/fmt/pull/1918>`_,
+  `#1939 <https://github.com/fmtlib/fmt/pull/1939>`_).
+  Thanks `@leolchat (Léonard Gérard) <https://github.com/leolchat>`_,
+  `@pepsiman (Malcolm Parsons) <https://github.com/pepsiman>`_,
+  `@Klaim (Joël Lamotte) <https://github.com/Klaim>`_,
+  `@ravijanjam (Ravi J) <https://github.com/ravijanjam>`_,
+  `@francesco-st <https://github.com/francesco-st>`_,
+  `@udnaan (Adnan) <https://github.com/udnaan>`_.
+
+* Added the ``FMT_REDUCE_INT_INSTANTIATIONS`` CMake option that reduces the
+  binary code size at the cost of some integer formatting performance. This can
+  be useful for extremely memory-constrained embedded systems
+  (`#1778 <https://github.com/fmtlib/fmt/issues/1778>`_,
+  `#1781 <https://github.com/fmtlib/fmt/pull/1781>`_).
+  Thanks `@kammce (Khalil Estell) <https://github.com/kammce>`_.
+
+* Added the ``FMT_USE_INLINE_NAMESPACES`` macro to control usage of inline
+  namespaces (`#1945 <https://github.com/fmtlib/fmt/pull/1945>`_).
+  Thanks `@darklukee <https://github.com/darklukee>`_.
+
+* Improved build configuration
+  (`#1760 <https://github.com/fmtlib/fmt/pull/1760>`_,
+  `#1770 <https://github.com/fmtlib/fmt/pull/1770>`_,
+  `#1779 <https://github.com/fmtlib/fmt/issues/1779>`_,
+  `#1783 <https://github.com/fmtlib/fmt/pull/1783>`_,
+  `#1823 <https://github.com/fmtlib/fmt/pull/1823>`_).
+  Thanks `@dvetutnev (Dmitriy Vetutnev) <https://github.com/dvetutnev>`_,
+  `@xvitaly (Vitaly Zaitsev) <https://github.com/xvitaly>`_,
+  `@tambry (Raul Tambre) <https://github.com/tambry>`_,
+  `@medithe <https://github.com/medithe>`_,
+  `@martinwuehrer (Martin Wührer) <https://github.com/martinwuehrer>`_.
+
+* Fixed various warnings and compilation issues
+  (`#1790 <https://github.com/fmtlib/fmt/pull/1790>`_,
+  `#1802 <https://github.com/fmtlib/fmt/pull/1802>`_,
+  `#1808 <https://github.com/fmtlib/fmt/pull/1808>`_,
+  `#1810 <https://github.com/fmtlib/fmt/issues/1810>`_,
+  `#1811 <https://github.com/fmtlib/fmt/issues/1811>`_,
+  `#1812 <https://github.com/fmtlib/fmt/pull/1812>`_,
+  `#1814 <https://github.com/fmtlib/fmt/pull/1814>`_,
+  `#1816 <https://github.com/fmtlib/fmt/pull/1816>`_,
+  `#1817 <https://github.com/fmtlib/fmt/pull/1817>`_,
+  `#1818 <https://github.com/fmtlib/fmt/pull/1818>`_,
+  `#1825 <https://github.com/fmtlib/fmt/issues/1825>`_,
+  `#1836 <https://github.com/fmtlib/fmt/pull/1836>`_,
+  `#1855 <https://github.com/fmtlib/fmt/pull/1855>`_,
+  `#1856 <https://github.com/fmtlib/fmt/pull/1856>`_,
+  `#1860 <https://github.com/fmtlib/fmt/pull/1860>`_,
+  `#1877 <https://github.com/fmtlib/fmt/pull/1877>`_,
+  `#1879 <https://github.com/fmtlib/fmt/pull/1879>`_,
+  `#1880 <https://github.com/fmtlib/fmt/pull/1880>`_,
+  `#1896 <https://github.com/fmtlib/fmt/issues/1896>`_,
+  `#1897 <https://github.com/fmtlib/fmt/pull/1897>`_,
+  `#1898 <https://github.com/fmtlib/fmt/pull/1898>`_,
+  `#1904 <https://github.com/fmtlib/fmt/issues/1904>`_,
+  `#1908 <https://github.com/fmtlib/fmt/pull/1908>`_,
+  `#1911 <https://github.com/fmtlib/fmt/issues/1911>`_,
+  `#1912 <https://github.com/fmtlib/fmt/issues/1912>`_,
+  `#1928 <https://github.com/fmtlib/fmt/issues/1928>`_,
+  `#1929 <https://github.com/fmtlib/fmt/pull/1929>`_,
+  `#1935 <https://github.com/fmtlib/fmt/issues/1935>`_
+  `#1937 <https://github.com/fmtlib/fmt/pull/1937>`_,
+  `#1942 <https://github.com/fmtlib/fmt/pull/1942>`_,
+  `#1949 <https://github.com/fmtlib/fmt/issues/1949>`_).
+  Thanks `@TheQwertiest <https://github.com/TheQwertiest>`_,
+  `@medithe <https://github.com/medithe>`_,
+  `@martinwuehrer (Martin Wührer) <https://github.com/martinwuehrer>`_,
+  `@n16h7hunt3r <https://github.com/n16h7hunt3r>`_,
+  `@Othereum (Seokjin Lee) <https://github.com/Othereum>`_,
+  `@gsjaardema (Greg Sjaardema) <https://github.com/gsjaardema>`_,
+  `@AlexanderLanin (Alexander Lanin) <https://github.com/AlexanderLanin>`_,
+  `@gcerretani (Giovanni Cerretani) <https://github.com/gcerretani>`_,
+  `@chronoxor (Ivan Shynkarenka) <https://github.com/chronoxor>`_,
+  `@noizefloor (Jan Schwers) <https://github.com/noizefloor>`_,
+  `@akohlmey (Axel Kohlmeyer) <https://github.com/akohlmey>`_,
+  `@jk-jeon (Junekey Jeon) <https://github.com/jk-jeon>`_,
+  `@rimathia <https://github.com/rimathia>`_,
+  `@rglarix (Riccardo Ghetta (larix)) <https://github.com/rglarix>`_,
+  `@moiwi <https://github.com/moiwi>`_,
+  `@heckad (Kazantcev Andrey) <https://github.com/heckad>`_,
+  `@MarcDirven <https://github.com/MarcDirven>`_.
+  `@BartSiwek (Bart Siwek) <https://github.com/BartSiwek>`_,
+  `@darklukee <https://github.com/darklukee>`_.
+
+7.0.3 - 2020-08-06
+------------------
+
+* Worked around broken ``numeric_limits`` for 128-bit integers
+  (`#1787 <https://github.com/fmtlib/fmt/issues/1787>`_).
+
+* Added error reporting on missing named arguments
+  (`#1796 <https://github.com/fmtlib/fmt/issues/1796>`_).
+
+* Stopped using 128-bit integers with clang-cl
+  (`#1800 <https://github.com/fmtlib/fmt/pull/1800>`_).
+  Thanks `@Kingcom <https://github.com/Kingcom>`_.
+
+* Fixed issues in locale-specific integer formatting
+  (`#1782 <https://github.com/fmtlib/fmt/issues/1782>`_,
+  `#1801 <https://github.com/fmtlib/fmt/issues/1801>`_).
+
+7.0.2 - 2020-07-29
+------------------
+
+* Worked around broken ``numeric_limits`` for 128-bit integers
+  (`#1725 <https://github.com/fmtlib/fmt/issues/1725>`_).
+
+* Fixed compatibility with CMake 3.4
+  (`#1779 <https://github.com/fmtlib/fmt/issues/1779>`_).
+
+* Fixed handling of digit separators in locale-specific formatting
+  (`#1782 <https://github.com/fmtlib/fmt/issues/1782>`_).
+
+7.0.1 - 2020-07-07
+------------------
+
+* Updated the inline version namespace name.
+
+* Worked around a gcc bug in mangling of alias templates
+  (`#1753 <https://github.com/fmtlib/fmt/issues/1753>`_).
+
+* Fixed a linkage error on Windows
+  (`#1757 <https://github.com/fmtlib/fmt/issues/1757>`_).
+  Thanks `@Kurkin (Dmitry Kurkin) <https://github.com/Kurkin>`_.
+
+* Fixed minor issues with the documentation.
+
+7.0.0 - 2020-07-05
+------------------
+
+* Reduced the library size. For example, on macOS a stripped test binary
+  statically linked with {fmt} `shrank from ~368k to less than 100k
+  <http://www.zverovich.net/2020/05/21/reducing-library-size.html>`_.
+
+* Added a simpler and more efficient `format string compilation API
+  <https://fmt.dev/7.0.0/api.html#compile-api>`_:
+
+  .. code:: c++
+
+     #include <fmt/compile.h>
+
+     // Converts 42 into std::string using the most efficient method and no
+     // runtime format string processing.
+     std::string s = fmt::format(FMT_COMPILE("{}"), 42);
+
+  The old ``fmt::compile`` API is now deprecated.
+
+* Optimized integer formatting: ``format_to`` with format string compilation
+  and a stack-allocated buffer is now `faster than to_chars on both
+  libc++ and libstdc++
+  <http://www.zverovich.net/2020/06/13/fast-int-to-string-revisited.html>`_.
+
+* Optimized handling of small format strings. For example,
+
+  .. code:: c++
+
+      fmt::format("Result: {}: ({},{},{},{})", str1, str2, str3, str4, str5)
+
+  is now ~40% faster (`#1685 <https://github.com/fmtlib/fmt/issues/1685>`_).
+
+* Applied extern templates to improve compile times when using the core API
+  and ``fmt/format.h`` (`#1452 <https://github.com/fmtlib/fmt/issues/1452>`_).
+  For example, on macOS with clang the compile time of a test translation unit
+  dropped from 2.3s to 0.3s with ``-O2`` and from 0.6s to 0.3s with the default
+  settings (``-O0``).
+
+  Before (``-O2``)::
+
+    % time c++ -c test.cc -I include -std=c++17 -O2
+    c++ -c test.cc -I include -std=c++17 -O2  2.22s user 0.08s system 99% cpu 2.311 total
+
+  After (``-O2``)::
+
+    % time c++ -c test.cc -I include -std=c++17 -O2
+    c++ -c test.cc -I include -std=c++17 -O2  0.26s user 0.04s system 98% cpu 0.303 total
+
+  Before (default)::
+
+    % time c++ -c test.cc -I include -std=c++17
+    c++ -c test.cc -I include -std=c++17  0.53s user 0.06s system 98% cpu 0.601 total
+
+  After (default)::
+
+    % time c++ -c test.cc -I include -std=c++17
+    c++ -c test.cc -I include -std=c++17  0.24s user 0.06s system 98% cpu 0.301 total
+
+  It is still recommended to use ``fmt/core.h`` instead of ``fmt/format.h`` but
+  the compile time difference is now smaller. Thanks
+  `@alex3d <https://github.com/alex3d>`_ for the suggestion.
+
+* Named arguments are now stored on stack (no dynamic memory allocations) and
+  the compiled code is more compact and efficient. For example
+
+  .. code:: c++
+
+     #include <fmt/core.h>
+
+     int main() {
+       fmt::print("The answer is {answer}\n", fmt::arg("answer", 42));
+     }
+
+  compiles to just (`godbolt <https://godbolt.org/z/NcfEp_>`__)
+
+  .. code:: asm
+
+      .LC0:
+              .string "answer"
+      .LC1:
+              .string "The answer is {answer}\n"
+      main:
+              sub     rsp, 56
+              mov     edi, OFFSET FLAT:.LC1
+              mov     esi, 23
+              movabs  rdx, 4611686018427387905
+              lea     rax, [rsp+32]
+              lea     rcx, [rsp+16]
+              mov     QWORD PTR [rsp+8], 1
+              mov     QWORD PTR [rsp], rax
+              mov     DWORD PTR [rsp+16], 42
+              mov     QWORD PTR [rsp+32], OFFSET FLAT:.LC0
+              mov     DWORD PTR [rsp+40], 0
+              call    fmt::v6::vprint(fmt::v6::basic_string_view<char>,
+                                      fmt::v6::format_args)
+              xor     eax, eax
+              add     rsp, 56
+              ret
+
+          .L.str.1:
+                  .asciz  "answer"
+
+* Implemented compile-time checks for dynamic width and precision
+  (`#1614 <https://github.com/fmtlib/fmt/issues/1614>`_):
+
+  .. code:: c++
+
+     #include <fmt/format.h>
+
+     int main() {
+       fmt::print(FMT_STRING("{0:{1}}"), 42);
+     }
+
+  now gives a compilation error because argument 1 doesn't exist::
+
+    In file included from test.cc:1:
+    include/fmt/format.h:2726:27: error: constexpr variable 'invalid_format' must be
+    initialized by a constant expression
+      FMT_CONSTEXPR_DECL bool invalid_format =
+                              ^
+    ...
+    include/fmt/core.h:569:26: note: in call to
+    '&checker(s, {}).context_->on_error(&"argument not found"[0])'
+        if (id >= num_args_) on_error("argument not found");
+                            ^
+
+* Added sentinel support to ``fmt::join``
+  (`#1689 <https://github.com/fmtlib/fmt/pull/1689>`_)
+
+  .. code:: c++
+
+    struct zstring_sentinel {};
+    bool operator==(const char* p, zstring_sentinel) { return *p == '\0'; }
+    bool operator!=(const char* p, zstring_sentinel) { return *p != '\0'; }
+
+    struct zstring {
+      const char* p;
+      const char* begin() const { return p; }
+      zstring_sentinel end() const { return {}; }
+    };
+
+    auto s = fmt::format("{}", fmt::join(zstring{"hello"}, "_"));
+    // s == "h_e_l_l_o"
+
+  Thanks `@BRevzin (Barry Revzin) <https://github.com/BRevzin>`_.
+
+* Added support for named arguments, ``clear`` and ``reserve`` to
+  ``dynamic_format_arg_store``
+  (`#1655 <https://github.com/fmtlib/fmt/issues/1655>`_,
+  `#1663 <https://github.com/fmtlib/fmt/pull/1663>`_,
+  `#1674 <https://github.com/fmtlib/fmt/pull/1674>`_,
+  `#1677 <https://github.com/fmtlib/fmt/pull/1677>`_).
+  Thanks `@vsolontsov-ll (Vladimir Solontsov)
+  <https://github.com/vsolontsov-ll>`_.
+
+* Added support for the ``'c'`` format specifier to integral types for
+  compatibility with ``std::format``
+  (`#1652 <https://github.com/fmtlib/fmt/issues/1652>`_).
+
+* Replaced the ``'n'`` format specifier with ``'L'`` for compatibility with
+  ``std::format`` (`#1624 <https://github.com/fmtlib/fmt/issues/1624>`_).
+  The ``'n'`` specifier can be enabled via the ``FMT_DEPRECATED_N_SPECIFIER``
+  macro.
+
+* The ``'='`` format specifier is now disabled by default for compatibility with
+  ``std::format``. It can be enabled via the ``FMT_DEPRECATED_NUMERIC_ALIGN``
+  macro.
+
+* Removed the following deprecated APIs:
+
+  * ``FMT_STRING_ALIAS`` and ``fmt`` macros - replaced by ``FMT_STRING``
+  * ``fmt::basic_string_view::char_type`` - replaced by
+    ``fmt::basic_string_view::value_type``
+  * ``convert_to_int``
+  * ``format_arg_store::types``
+  * ``*parse_context`` - replaced by ``*format_parse_context``
+  * ``FMT_DEPRECATED_INCLUDE_OS``
+  * ``FMT_DEPRECATED_PERCENT`` - incompatible with ``std::format``
+  * ``*writer`` - replaced by compiled format API
+
+* Renamed the ``internal`` namespace to ``detail``
+  (`#1538 <https://github.com/fmtlib/fmt/issues/1538>`_). The former is still
+  provided as an alias if the ``FMT_USE_INTERNAL`` macro is defined.
+
+* Improved compatibility between ``fmt::printf`` with the standard specs
+  (`#1595 <https://github.com/fmtlib/fmt/issues/1595>`_,
+  `#1682 <https://github.com/fmtlib/fmt/pull/1682>`_,
+  `#1683 <https://github.com/fmtlib/fmt/pull/1683>`_,
+  `#1687 <https://github.com/fmtlib/fmt/pull/1687>`_,
+  `#1699 <https://github.com/fmtlib/fmt/pull/1699>`_).
+  Thanks `@rimathia <https://github.com/rimathia>`_.
+
+* Fixed handling of ``operator<<`` overloads that use ``copyfmt``
+  (`#1666 <https://github.com/fmtlib/fmt/issues/1666>`_).
+
+* Added the ``FMT_OS`` CMake option to control inclusion of OS-specific APIs
+  in the fmt target. This can be useful for embedded platforms
+  (`#1654 <https://github.com/fmtlib/fmt/issues/1654>`_,
+  `#1656 <https://github.com/fmtlib/fmt/pull/1656>`_).
+  Thanks `@kwesolowski (Krzysztof Wesolowski)
+  <https://github.com/kwesolowski>`_.
+
+* Replaced ``FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION`` with the ``FMT_FUZZ``
+  macro to prevent interferring with fuzzing of projects using {fmt}
+  (`#1650 <https://github.com/fmtlib/fmt/pull/1650>`_).
+  Thanks `@asraa (Asra Ali) <https://github.com/asraa>`_.
+
+* Fixed compatibility with emscripten
+  (`#1636 <https://github.com/fmtlib/fmt/issues/1636>`_,
+  `#1637 <https://github.com/fmtlib/fmt/pull/1637>`_).
+  Thanks `@ArthurSonzogni (Arthur Sonzogni)
+  <https://github.com/ArthurSonzogni>`_.
+
+* Improved documentation
+  (`#704 <https://github.com/fmtlib/fmt/issues/704>`_,
+  `#1643 <https://github.com/fmtlib/fmt/pull/1643>`_,
+  `#1660 <https://github.com/fmtlib/fmt/pull/1660>`_,
+  `#1681 <https://github.com/fmtlib/fmt/pull/1681>`_,
+  `#1691 <https://github.com/fmtlib/fmt/pull/1691>`_,
+  `#1706 <https://github.com/fmtlib/fmt/pull/1706>`_,
+  `#1714 <https://github.com/fmtlib/fmt/pull/1714>`_,
+  `#1721 <https://github.com/fmtlib/fmt/pull/1721>`_,
+  `#1739 <https://github.com/fmtlib/fmt/pull/1739>`_,
+  `#1740 <https://github.com/fmtlib/fmt/pull/1740>`_,
+  `#1741 <https://github.com/fmtlib/fmt/pull/1741>`_,
+  `#1751 <https://github.com/fmtlib/fmt/pull/1751>`_).
+  Thanks `@senior7515 (Alexander Gallego) <https://github.com/senior7515>`_,
+  `@lsr0 (Lindsay Roberts) <https://github.com/lsr0>`_,
+  `@puetzk (Kevin Puetz) <https://github.com/puetzk>`_,
+  `@fpelliccioni (Fernando Pelliccioni) <https://github.com/fpelliccioni>`_,
+  Alexey Kuzmenko, `@jelly (jelle van der Waa) <https://github.com/jelly>`_,
+  `@claremacrae (Clare Macrae) <https://github.com/claremacrae>`_,
+  `@jiapengwen (文佳鹏) <https://github.com/jiapengwen>`_,
+  `@gsjaardema (Greg Sjaardema) <https://github.com/gsjaardema>`_,
+  `@alexey-milovidov <https://github.com/alexey-milovidov>`_.
+
+* Implemented various build configuration fixes and improvements
+  (`#1603 <https://github.com/fmtlib/fmt/pull/1603>`_,
+  `#1657 <https://github.com/fmtlib/fmt/pull/1657>`_,
+  `#1702 <https://github.com/fmtlib/fmt/pull/1702>`_,
+  `#1728 <https://github.com/fmtlib/fmt/pull/1728>`_).
+  Thanks `@scramsby (Scott Ramsby) <https://github.com/scramsby>`_,
+  `@jtojnar (Jan Tojnar) <https://github.com/jtojnar>`_,
+  `@orivej (Orivej Desh) <https://github.com/orivej>`_,
+  `@flagarde <https://github.com/flagarde>`_.
+
+* Fixed various warnings and compilation issues
+  (`#1616 <https://github.com/fmtlib/fmt/pull/1616>`_,
+  `#1620 <https://github.com/fmtlib/fmt/issues/1620>`_,
+  `#1622 <https://github.com/fmtlib/fmt/issues/1622>`_,
+  `#1625 <https://github.com/fmtlib/fmt/issues/1625>`_,
+  `#1627 <https://github.com/fmtlib/fmt/pull/1627>`_,
+  `#1628 <https://github.com/fmtlib/fmt/issues/1628>`_,
+  `#1629 <https://github.com/fmtlib/fmt/pull/1629>`_,
+  `#1631 <https://github.com/fmtlib/fmt/issues/1631>`_,
+  `#1633 <https://github.com/fmtlib/fmt/pull/1633>`_,
+  `#1649 <https://github.com/fmtlib/fmt/pull/1649>`_,
+  `#1658 <https://github.com/fmtlib/fmt/issues/1658>`_,
+  `#1661 <https://github.com/fmtlib/fmt/pull/1661>`_,
+  `#1667 <https://github.com/fmtlib/fmt/pull/1667>`_,
+  `#1668 <https://github.com/fmtlib/fmt/issues/1668>`_,
+  `#1669 <https://github.com/fmtlib/fmt/pull/1669>`_,
+  `#1692 <https://github.com/fmtlib/fmt/issues/1692>`_,
+  `#1696 <https://github.com/fmtlib/fmt/pull/1696>`_,
+  `#1697 <https://github.com/fmtlib/fmt/pull/1697>`_,
+  `#1707 <https://github.com/fmtlib/fmt/issues/1707>`_,
+  `#1712 <https://github.com/fmtlib/fmt/pull/1712>`_,
+  `#1716 <https://github.com/fmtlib/fmt/pull/1716>`_,
+  `#1722 <https://github.com/fmtlib/fmt/pull/1722>`_,
+  `#1724 <https://github.com/fmtlib/fmt/issues/1724>`_,
+  `#1729 <https://github.com/fmtlib/fmt/pull/1729>`_,
+  `#1738 <https://github.com/fmtlib/fmt/pull/1738>`_,
+  `#1742 <https://github.com/fmtlib/fmt/issues/1742>`_,
+  `#1743 <https://github.com/fmtlib/fmt/issues/1743>`_,
+  `#1744 <https://github.com/fmtlib/fmt/pull/1744>`_,
+  `#1747 <https://github.com/fmtlib/fmt/issues/1747>`_,
+  `#1750 <https://github.com/fmtlib/fmt/pull/1750>`_).
+  Thanks `@gsjaardema (Greg Sjaardema) <https://github.com/gsjaardema>`_,
+  `@gabime (Gabi Melman) <https://github.com/gabime>`_,
+  `@johnor (Johan) <https://github.com/johnor>`_,
+  `@Kurkin (Dmitry Kurkin) <https://github.com/Kurkin>`_,
+  `@invexed (James Beach) <https://github.com/invexed>`_,
+  `@peterbell10 <https://github.com/peterbell10>`_,
+  `@daixtrose (Markus Werle) <https://github.com/daixtrose>`_,
+  `@petrutlucian94 (Lucian Petrut) <https://github.com/petrutlucian94>`_,
+  `@Neargye (Daniil Goncharov) <https://github.com/Neargye>`_,
+  `@ambitslix (Attila M. Szilagyi) <https://github.com/ambitslix>`_,
+  `@gabime (Gabi Melman) <https://github.com/gabime>`_,
+  `@erthink (Leonid Yuriev) <https://github.com/erthink>`_,
+  `@tohammer (Tobias Hammer) <https://github.com/tohammer>`_,
+  `@0x8000-0000 (Florin Iucha) <https://github.com/0x8000-0000>`_.
+
+6.2.1 - 2020-05-09
+------------------
+
+* Fixed ostream support in ``sprintf``
+  (`#1631 <https://github.com/fmtlib/fmt/issues/1631>`_).
+
+* Fixed type detection when using implicit conversion to ``string_view`` and
+  ostream ``operator<<`` inconsistently
+  (`#1662 <https://github.com/fmtlib/fmt/issues/1662>`_).
+
+6.2.0 - 2020-04-05
+------------------
+
+* Improved error reporting when trying to format an object of a non-formattable
+  type:
+
+  .. code:: c++
+
+     fmt::format("{}", S());
+
+  now gives::
+
+    include/fmt/core.h:1015:5: error: static_assert failed due to requirement
+    'formattable' "Cannot format argument. To make type T formattable provide a
+    formatter<T> specialization:
+    https://fmt.dev/latest/api.html#formatting-user-defined-types"
+        static_assert(
+        ^
+    ...
+    note: in instantiation of function template specialization
+    'fmt::v6::format<char [3], S, char>' requested here
+      fmt::format("{}", S());
+           ^
+
+  if ``S`` is not formattable.
+
+* Reduced the library size by ~10%.
+
+* Always print decimal point if ``#`` is specified
+  (`#1476 <https://github.com/fmtlib/fmt/issues/1476>`_,
+  `#1498 <https://github.com/fmtlib/fmt/issues/1498>`_):
+
+  .. code:: c++
+
+     fmt::print("{:#.0f}", 42.0);
+
+  now prints ``42.``
+
+* Implemented the ``'L'`` specifier for locale-specific numeric formatting to
+  improve compatibility with ``std::format``. The ``'n'`` specifier is now
+  deprecated and will be removed in the next major release.
+
+* Moved OS-specific APIs such as ``windows_error`` from ``fmt/format.h`` to
+  ``fmt/os.h``. You can define ``FMT_DEPRECATED_INCLUDE_OS`` to automatically
+  include ``fmt/os.h`` from ``fmt/format.h`` for compatibility but this will be
+  disabled in the next major release.
+
+* Added precision overflow detection in floating-point formatting.
+
+* Implemented detection of invalid use of ``fmt::arg``.
+
+* Used ``type_identity`` to block unnecessary template argument deduction.
+  Thanks Tim Song.
+
+* Improved UTF-8 handling
+  (`#1109 <https://github.com/fmtlib/fmt/issues/1109>`_):
+
+  .. code:: c++
+
+     fmt::print("┌{0:─^{2}}┐\n"
+                "│{1: ^{2}}│\n"
+                "└{0:─^{2}}┘\n", "", "Привет, мир!", 20);
+
+  now prints::
+
+     ┌────────────────────┐
+     │    Привет, мир!    │
+     └────────────────────┘
+
+  on systems that support Unicode.
+
+* Added experimental dynamic argument storage
+  (`#1170 <https://github.com/fmtlib/fmt/issues/1170>`_,
+  `#1584 <https://github.com/fmtlib/fmt/pull/1584>`_):
+
+  .. code:: c++
+
+     fmt::dynamic_format_arg_store<fmt::format_context> store;
+     store.push_back("answer");
+     store.push_back(42);
+     fmt::vprint("The {} is {}.\n", store);
+  
+  prints::
+
+     The answer is 42.
+
+  Thanks `@vsolontsov-ll (Vladimir Solontsov)
+  <https://github.com/vsolontsov-ll>`_.
+
+* Made ``fmt::join`` accept ``initializer_list``
+  (`#1591 <https://github.com/fmtlib/fmt/pull/1591>`_).
+  Thanks `@Rapotkinnik (Nikolay Rapotkin) <https://github.com/Rapotkinnik>`_.
+
+* Fixed handling of empty tuples
+  (`#1588 <https://github.com/fmtlib/fmt/issues/1588>`_).
+
+* Fixed handling of output iterators in ``format_to_n``
+  (`#1506 <https://github.com/fmtlib/fmt/issues/1506>`_).
+
+* Fixed formatting of ``std::chrono::duration`` types to wide output
+  (`#1533 <https://github.com/fmtlib/fmt/pull/1533>`_).
+  Thanks `@zeffy (pilao) <https://github.com/zeffy>`_.
+
+* Added const ``begin`` and ``end`` overload to buffers
+  (`#1553 <https://github.com/fmtlib/fmt/pull/1553>`_).
+  Thanks `@dominicpoeschko <https://github.com/dominicpoeschko>`_.
+
+* Added the ability to disable floating-point formatting via ``FMT_USE_FLOAT``,
+  ``FMT_USE_DOUBLE`` and ``FMT_USE_LONG_DOUBLE`` macros for extremely
+  memory-constrained embedded system
+  (`#1590 <https://github.com/fmtlib/fmt/pull/1590>`_).
+  Thanks `@albaguirre (Alberto Aguirre) <https://github.com/albaguirre>`_.
+
+* Made ``FMT_STRING`` work with ``constexpr`` ``string_view``
+  (`#1589 <https://github.com/fmtlib/fmt/pull/1589>`_).
+  Thanks `@scramsby (Scott Ramsby) <https://github.com/scramsby>`_.
+
+* Implemented a minor optimization in the format string parser
+  (`#1560 <https://github.com/fmtlib/fmt/pull/1560>`_).
+  Thanks `@IkarusDeveloper <https://github.com/IkarusDeveloper>`_.
+
+* Improved attribute detection
+  (`#1469 <https://github.com/fmtlib/fmt/pull/1469>`_,
+  `#1475 <https://github.com/fmtlib/fmt/pull/1475>`_,
+  `#1576 <https://github.com/fmtlib/fmt/pull/1576>`_).
+  Thanks `@federico-busato (Federico) <https://github.com/federico-busato>`_,
+  `@chronoxor (Ivan Shynkarenka) <https://github.com/chronoxor>`_,
+  `@refnum <https://github.com/refnum>`_.
+
+* Improved documentation
+  (`#1481 <https://github.com/fmtlib/fmt/pull/1481>`_,
+  `#1523 <https://github.com/fmtlib/fmt/pull/1523>`_).
+  Thanks `@JackBoosY (Jack·Boos·Yu) <https://github.com/JackBoosY>`_,
+  `@imba-tjd (谭九鼎) <https://github.com/imba-tjd>`_.
+
+* Fixed symbol visibility on Linux when compiling with ``-fvisibility=hidden``
+  (`#1535 <https://github.com/fmtlib/fmt/pull/1535>`_).
+  Thanks `@milianw (Milian Wolff) <https://github.com/milianw>`_.
+
+* Implemented various build configuration fixes and improvements
+  (`#1264 <https://github.com/fmtlib/fmt/issues/1264>`_,
+  `#1460 <https://github.com/fmtlib/fmt/issues/1460>`_,
+  `#1534 <https://github.com/fmtlib/fmt/pull/1534>`_,
+  `#1536 <https://github.com/fmtlib/fmt/issues/1536>`_,
+  `#1545 <https://github.com/fmtlib/fmt/issues/1545>`_,
+  `#1546 <https://github.com/fmtlib/fmt/pull/1546>`_,
+  `#1566 <https://github.com/fmtlib/fmt/issues/1566>`_,
+  `#1582 <https://github.com/fmtlib/fmt/pull/1582>`_,
+  `#1597 <https://github.com/fmtlib/fmt/issues/1597>`_,
+  `#1598 <https://github.com/fmtlib/fmt/pull/1598>`_).
+  Thanks `@ambitslix (Attila M. Szilagyi) <https://github.com/ambitslix>`_,
+  `@jwillikers (Jordan Williams) <https://github.com/jwillikers>`_,
+  `@stac47 (Laurent Stacul) <https://github.com/stac47>`_.
+
+* Fixed various warnings and compilation issues
+  (`#1433 <https://github.com/fmtlib/fmt/pull/1433>`_,
+  `#1461 <https://github.com/fmtlib/fmt/issues/1461>`_,
+  `#1470 <https://github.com/fmtlib/fmt/pull/1470>`_,
+  `#1480 <https://github.com/fmtlib/fmt/pull/1480>`_,
+  `#1485 <https://github.com/fmtlib/fmt/pull/1485>`_,
+  `#1492 <https://github.com/fmtlib/fmt/pull/1492>`_,
+  `#1493 <https://github.com/fmtlib/fmt/issues/1493>`_,
+  `#1504 <https://github.com/fmtlib/fmt/issues/1504>`_,
+  `#1505 <https://github.com/fmtlib/fmt/pull/1505>`_,
+  `#1512 <https://github.com/fmtlib/fmt/pull/1512>`_,
+  `#1515 <https://github.com/fmtlib/fmt/issues/1515>`_,
+  `#1516 <https://github.com/fmtlib/fmt/pull/1516>`_,
+  `#1518 <https://github.com/fmtlib/fmt/pull/1518>`_,
+  `#1519 <https://github.com/fmtlib/fmt/pull/1519>`_,
+  `#1520 <https://github.com/fmtlib/fmt/pull/1520>`_,
+  `#1521 <https://github.com/fmtlib/fmt/pull/1521>`_,
+  `#1522 <https://github.com/fmtlib/fmt/pull/1522>`_,
+  `#1524 <https://github.com/fmtlib/fmt/issues/1524>`_,
+  `#1530 <https://github.com/fmtlib/fmt/pull/1530>`_,
+  `#1531 <https://github.com/fmtlib/fmt/issues/1531>`_,
+  `#1532 <https://github.com/fmtlib/fmt/pull/1532>`_,
+  `#1539 <https://github.com/fmtlib/fmt/issues/1539>`_,
+  `#1547 <https://github.com/fmtlib/fmt/issues/1547>`_,
+  `#1548 <https://github.com/fmtlib/fmt/issues/1548>`_,
+  `#1554 <https://github.com/fmtlib/fmt/pull/1554>`_,
+  `#1567 <https://github.com/fmtlib/fmt/issues/1567>`_,
+  `#1568 <https://github.com/fmtlib/fmt/pull/1568>`_,
+  `#1569 <https://github.com/fmtlib/fmt/pull/1569>`_,
+  `#1571 <https://github.com/fmtlib/fmt/pull/1571>`_,
+  `#1573 <https://github.com/fmtlib/fmt/pull/1573>`_,
+  `#1575 <https://github.com/fmtlib/fmt/pull/1575>`_,
+  `#1581 <https://github.com/fmtlib/fmt/pull/1581>`_,
+  `#1583 <https://github.com/fmtlib/fmt/issues/1583>`_,
+  `#1586 <https://github.com/fmtlib/fmt/issues/1586>`_,
+  `#1587 <https://github.com/fmtlib/fmt/issues/1587>`_,
+  `#1594 <https://github.com/fmtlib/fmt/issues/1594>`_,
+  `#1596 <https://github.com/fmtlib/fmt/pull/1596>`_,
+  `#1604 <https://github.com/fmtlib/fmt/issues/1604>`_,
+  `#1606 <https://github.com/fmtlib/fmt/pull/1606>`_,
+  `#1607 <https://github.com/fmtlib/fmt/issues/1607>`_,
+  `#1609 <https://github.com/fmtlib/fmt/issues/1609>`_).
+  Thanks `@marti4d (Chris Martin) <https://github.com/marti4d>`_,
+  `@iPherian <https://github.com/iPherian>`_,
+  `@parkertomatoes <https://github.com/parkertomatoes>`_,
+  `@gsjaardema (Greg Sjaardema) <https://github.com/gsjaardema>`_,
+  `@chronoxor (Ivan Shynkarenka) <https://github.com/chronoxor>`_,
+  `@DanielaE (Daniela Engert) <https://github.com/DanielaE>`_,
+  `@torsten48 <https://github.com/torsten48>`_,
+  `@tohammer (Tobias Hammer) <https://github.com/tohammer>`_,
+  `@lefticus (Jason Turner) <https://github.com/lefticus>`_,
+  `@ryusakki (Haise) <https://github.com/ryusakki>`_,
+  `@adnsv (Alex Denisov) <https://github.com/adnsv>`_,
+  `@fghzxm <https://github.com/fghzxm>`_,
+  `@refnum <https://github.com/refnum>`_,
+  `@pramodk (Pramod Kumbhar) <https://github.com/pramodk>`_,
+  `@Spirrwell <https://github.com/Spirrwell>`_,
+  `@scramsby (Scott Ramsby) <https://github.com/scramsby>`_.
+
 6.1.2 - 2019-12-11
 ------------------
 
@@ -374,16 +1312,16 @@
      #include <fmt/compile.h>
 
      auto f = fmt::compile<int>("{}");
-     std::string s = fmt::format(f, 42); // can be called multiple times to format
-                                         // different values
+     std::string s = fmt::format(f, 42); // can be called multiple times to
+                                         // format different values
      // s == "42"
 
   It moves the cost of parsing a format string outside of the format function
   which can be beneficial when identically formatting many objects of the same
   types. Thanks `@stryku (Mateusz Janek) <https://github.com/stryku>`_.
 
-* Added the ``%`` format specifier that formats floating-point values as
-  percentages (`#1060 <https://github.com/fmtlib/fmt/pull/1060>`_,
+* Added experimental ``%`` format specifier that formats floating-point values
+  as percentages (`#1060 <https://github.com/fmtlib/fmt/pull/1060>`_,
   `#1069 <https://github.com/fmtlib/fmt/pull/1069>`_,
   `#1071 <https://github.com/fmtlib/fmt/pull/1071>`_):
 
@@ -1146,7 +2084,7 @@
 
 * Implemented ``constexpr`` parsing of format strings and `compile-time format
   string checks
-  <https://fmt.dev/dev/api.html#compile-time-format-string-checks>`_. For
+  <https://fmt.dev/latest/api.html#compile-time-format-string-checks>`_. For
   example
 
   .. code:: c++
@@ -1207,7 +2145,7 @@
             throw format_error("invalid specifier");
 
 * Added `iterator support
-  <https://fmt.dev/dev/api.html#output-iterator-support>`_:
+  <https://fmt.dev/latest/api.html#output-iterator-support>`_:
 
   .. code:: c++
 
@@ -1218,7 +2156,7 @@
      fmt::format_to(std::back_inserter(out), "{}", 42);
 
 * Added the `format_to_n
-  <https://fmt.dev/dev/api.html#_CPPv2N3fmt11format_to_nE8OutputItNSt6size_tE11string_viewDpRK4Args>`_
+  <https://fmt.dev/latest/api.html#_CPPv2N3fmt11format_to_nE8OutputItNSt6size_tE11string_viewDpRK4Args>`_
   function that restricts the output to the specified number of characters
   (`#298 <https://github.com/fmtlib/fmt/issues/298>`_):
 
@@ -1229,7 +2167,7 @@
      // out == "1234" (without terminating '\0')
 
 * Added the `formatted_size
-  <https://fmt.dev/dev/api.html#_CPPv2N3fmt14formatted_sizeE11string_viewDpRK4Args>`_
+  <https://fmt.dev/latest/api.html#_CPPv2N3fmt14formatted_sizeE11string_viewDpRK4Args>`_
   function for computing the output size:
 
   .. code:: c++
@@ -1239,7 +2177,7 @@
      auto size = fmt::formatted_size("{}", 12345); // size == 5
 
 * Improved compile times by reducing dependencies on standard headers and
-  providing a lightweight `core API <https://fmt.dev/dev/api.html#core-api>`_:
+  providing a lightweight `core API <https://fmt.dev/latest/api.html#core-api>`_:
 
   .. code:: c++
 
@@ -1251,7 +2189,7 @@
   <https://github.com/fmtlib/fmt#compile-time-and-code-bloat>`_.
 
 * Added the `make_format_args
-  <https://fmt.dev/dev/api.html#_CPPv2N3fmt16make_format_argsEDpRK4Args>`_
+  <https://fmt.dev/latest/api.html#_CPPv2N3fmt16make_format_argsEDpRK4Args>`_
   function for capturing formatting arguments:
 
   .. code:: c++
@@ -1333,7 +2271,7 @@
      fmt::format("{} {two}", 1, fmt::arg("two", 2));
 
 * Removed the write API in favor of the `format API
-  <https://fmt.dev/dev/api.html#format-api>`_ with compile-time handling of
+  <https://fmt.dev/latest/api.html#format-api>`_ with compile-time handling of
   format strings.
 
 * Disallowed formatting of multibyte strings into a wide character target
diff --git a/Externals/fmt/README.rst b/Externals/fmt/README.rst
index 162382ceca7b..acddc70ef183 100755
--- a/Externals/fmt/README.rst
+++ b/Externals/fmt/README.rst
@@ -7,153 +7,174 @@
 .. image:: https://ci.appveyor.com/api/projects/status/ehjkiefde6gucy1v
    :target: https://ci.appveyor.com/project/vitaut/fmt
 
-.. image:: https://oss-fuzz-build-logs.storage.googleapis.com/badges/libfmt.svg
-   :alt: fmt is continuously fuzzed att oss-fuzz
-   :target: https://bugs.chromium.org/p/oss-fuzz/issues/list?colspec=ID%20Type%20Component%20Status%20Proj%20Reported%20Owner%20Summary&q=proj%3Dlibfmt&can=1
+.. image:: https://oss-fuzz-build-logs.storage.googleapis.com/badges/fmt.svg
+   :alt: fmt is continuously fuzzed at oss-fuzz
+   :target: https://bugs.chromium.org/p/oss-fuzz/issues/list?\
+            colspec=ID%20Type%20Component%20Status%20Proj%20Reported%20Owner%20\
+            Summary&q=proj%3Dfmt&can=1
 
 .. image:: https://img.shields.io/badge/stackoverflow-fmt-blue.svg
    :alt: Ask questions at StackOverflow with the tag fmt
-   :target: http://stackoverflow.com/questions/tagged/fmt
+   :target: https://stackoverflow.com/questions/tagged/fmt
 
-**{fmt}** is an open-source formatting library for C++.
-It can be used as a safe and fast alternative to (s)printf and iostreams.
+**{fmt}** is an open-source formatting library providing a fast and safe
+alternative to C stdio and C++ iostreams.
 
-`Documentation <https://fmt.dev/latest/>`__
+If you like this project, please consider donating to BYSOL,
+an initiative to help victims of political repressions in Belarus:
+https://www.facebook.com/donate/759400044849707/108388587646909/.
 
-Q&A: ask questions on `StackOverflow with the tag fmt <http://stackoverflow.com/questions/tagged/fmt>`_.
+`Documentation <https://fmt.dev>`__
+
+Q&A: ask questions on `StackOverflow with the tag fmt
+<https://stackoverflow.com/questions/tagged/fmt>`_.
+
+Try {fmt} in `Compiler Explorer <https://godbolt.org/z/Eq5763>`_.
 
 Features
 --------
 
-* Replacement-based `format API <https://fmt.dev/dev/api.html>`_ with
-  positional arguments for localization.
-* `Format string syntax <https://fmt.dev/dev/syntax.html>`_ similar to the one
-  of `str.format <https://docs.python.org/3/library/stdtypes.html#str.format>`_
-  in Python.
+* Simple `format API <https://fmt.dev/latest/api.html>`_ with positional arguments
+  for localization
+* Implementation of `C++20 std::format
+  <https://en.cppreference.com/w/cpp/utility/format>`__
+* `Format string syntax <https://fmt.dev/latest/syntax.html>`_ similar to Python's
+  `format <https://docs.python.org/3/library/stdtypes.html#str.format>`_
+* Fast IEEE 754 floating-point formatter with correct rounding, shortness and
+  round-trip guarantees
 * Safe `printf implementation
-  <https://fmt.dev/latest/api.html#printf-formatting>`_ including
-  the POSIX extension for positional arguments.
-* Implementation of `C++20 std::format <https://fmt.dev/Text%20Formatting.html>`__.
-* Support for user-defined types.
+  <https://fmt.dev/latest/api.html#printf-formatting>`_ including the POSIX
+  extension for positional arguments
+* Extensibility: `support for user-defined types
+  <https://fmt.dev/latest/api.html#formatting-user-defined-types>`_
 * High performance: faster than common standard library implementations of
-  `printf <http://en.cppreference.com/w/cpp/io/c/fprintf>`_ and
-  iostreams. See `Speed tests`_ and `Fast integer to string conversion in C++
-  <http://zverovich.net/2013/09/07/integer-to-string-conversion-in-cplusplus.html>`_.
-* Small code size both in terms of source code (the minimum configuration
-  consists of just three header files, ``core.h``, ``format.h`` and
-  ``format-inl.h``) and compiled code. See `Compile time and code bloat`_.
-* Reliability: the library has an extensive set of `unit tests
-  <https://github.com/fmtlib/fmt/tree/master/test>`_ and is continuously fuzzed.
+  ``(s)printf``, iostreams, ``to_string`` and ``to_chars``, see `Speed tests`_
+  and `Converting a hundred million integers to strings per second
+  <http://www.zverovich.net/2020/06/13/fast-int-to-string-revisited.html>`_
+* Small code size both in terms of source code with the minimum configuration
+  consisting of just three files, ``core.h``, ``format.h`` and ``format-inl.h``,
+  and compiled code; see `Compile time and code bloat`_
+* Reliability: the library has an extensive set of `tests
+  <https://github.com/fmtlib/fmt/tree/master/test>`_ and is `continuously fuzzed
+  <https://bugs.chromium.org/p/oss-fuzz/issues/list?colspec=ID%20Type%20
+  Component%20Status%20Proj%20Reported%20Owner%20Summary&q=proj%3Dfmt&can=1>`_
 * Safety: the library is fully type safe, errors in format strings can be
   reported at compile time, automatic memory management prevents buffer overflow
-  errors.
+  errors
 * Ease of use: small self-contained code base, no external dependencies,
   permissive MIT `license
   <https://github.com/fmtlib/fmt/blob/master/LICENSE.rst>`_
 * `Portability <https://fmt.dev/latest/index.html#portability>`_ with
-  consistent output across platforms and support for older compilers.
-* Clean warning-free codebase even on high warning levels
-  (``-Wall -Wextra -pedantic``).
-* Support for wide strings.
-* Optional header-only configuration enabled with the ``FMT_HEADER_ONLY`` macro.
+  consistent output across platforms and support for older compilers
+* Clean warning-free codebase even on high warning levels such as
+  ``-Wall -Wextra -pedantic``
+* Locale-independence by default
+* Optional header-only configuration enabled with the ``FMT_HEADER_ONLY`` macro
 
-See the `documentation <https://fmt.dev/latest/>`_ for more details.
+See the `documentation <https://fmt.dev>`_ for more details.
 
 Examples
 --------
 
-Print ``Hello, world!`` to ``stdout``:
+**Print to stdout** (`run <https://godbolt.org/z/Tevcjh>`_)
+
+.. code:: c++
+
+    #include <fmt/core.h>
+    
+    int main() {
+      fmt::print("Hello, world!\n");
+    }
+
+**Format a string** (`run <https://godbolt.org/z/oK8h33>`_)
 
 .. code:: c++
 
-    fmt::print("Hello, {}!", "world");  // Python-like format string syntax
-    fmt::printf("Hello, %s!", "world"); // printf format string syntax
+    std::string s = fmt::format("The answer is {}.", 42);
+    // s == "The answer is 42."
 
-Format a string and use positional arguments:
+**Format a string using positional arguments** (`run <https://godbolt.org/z/Yn7Txe>`_)
 
 .. code:: c++
 
     std::string s = fmt::format("I'd rather be {1} than {0}.", "right", "happy");
     // s == "I'd rather be happy than right."
 
-Check a format string at compile time:
+**Print chrono durations** (`run <https://godbolt.org/z/K8s4Mc>`_)
 
 .. code:: c++
 
-    // test.cc
-    #include <fmt/format.h>
-    std::string s = format(FMT_STRING("{2}"), 42);
+    #include <fmt/chrono.h>
 
-.. code::
+    int main() {
+      using namespace std::literals::chrono_literals;
+      fmt::print("Default format: {} {}\n", 42s, 100ms);
+      fmt::print("strftime-like format: {:%H:%M:%S}\n", 3h + 15min + 30s);
+    }
+
+Output::
 
-    $ c++ -Iinclude -std=c++14 test.cc
-    ...
-    test.cc:4:17: note: in instantiation of function template specialization 'fmt::v5::format<S, int>' requested here
-    std::string s = format(FMT_STRING("{2}"), 42);
-                    ^
-    include/fmt/core.h:778:19: note: non-constexpr function 'on_error' cannot be used in a constant expression
-        ErrorHandler::on_error(message);
-                      ^
-    include/fmt/format.h:2226:16: note: in call to '&checker.context_->on_error(&"argument index out of range"[0])'
-          context_.on_error("argument index out of range");
-                   ^
+    Default format: 42s 100ms
+    strftime-like format: 03:15:30
 
-Use {fmt} as a safe portable replacement for ``itoa``
-(`godbolt <https://godbolt.org/g/NXmpU4>`_):
+**Print a container** (`run <https://godbolt.org/z/MjsY7c>`_)
 
 .. code:: c++
 
-    fmt::memory_buffer buf;
-    format_to(buf, "{}", 42);    // replaces itoa(42, buffer, 10)
-    format_to(buf, "{:x}", 42);  // replaces itoa(42, buffer, 16)
-    // access the string with to_string(buf) or buf.data()
+    #include <vector>
+    #include <fmt/ranges.h>
 
-Format objects of user-defined types via a simple `extension API
-<https://fmt.dev/latest/api.html#formatting-user-defined-types>`_:
+    int main() {
+      std::vector<int> v = {1, 2, 3};
+      fmt::print("{}\n", v);
+    }
 
-.. code:: c++
+Output::
 
-    #include "fmt/format.h"
+    {1, 2, 3}
 
-    struct date {
-      int year, month, day;
-    };
+**Check a format string at compile time**
 
-    template <>
-    struct fmt::formatter<date> {
-      constexpr auto parse(format_parse_context& ctx) { return ctx.begin(); }
+.. code:: c++
 
-      template <typename FormatContext>
-      auto format(const date& d, FormatContext& ctx) {
-        return format_to(ctx.out(), "{}-{}-{}", d.year, d.month, d.day);
-      }
-    };
+    std::string s = fmt::format(FMT_STRING("{:d}"), "don't panic");
 
-    std::string s = fmt::format("The date is {}", date{2012, 12, 9});
-    // s == "The date is 2012-12-9"
+This gives a compile-time error because ``d`` is an invalid format specifier for
+a string.
 
-Create your own functions similar to `format
-<https://fmt.dev/latest/api.html#format>`_ and
-`print <https://fmt.dev/latest/api.html#print>`_
-which take arbitrary arguments (`godbolt <https://godbolt.org/g/MHjHVf>`_):
+**Write a file from a single thread**
 
 .. code:: c++
 
-    // Prints formatted error message.
-    void vreport_error(const char* format, fmt::format_args args) {
-      fmt::print("Error: ");
-      fmt::vprint(format, args);
+    #include <fmt/os.h>
+
+    int main() {
+      auto out = fmt::output_file("guide.txt");
+      out.print("Don't {}", "Panic");
     }
-    template <typename... Args>
-    void report_error(const char* format, const Args & ... args) {
-      vreport_error(format, fmt::make_format_args(args...));
+
+This can be `5 to 9 times faster than fprintf
+<http://www.zverovich.net/2020/08/04/optimal-file-buffer-size.html>`_.
+
+**Print with colors and text styles**
+
+.. code:: c++
+
+    #include <fmt/color.h>
+
+    int main() {
+      fmt::print(fg(fmt::color::crimson) | fmt::emphasis::bold,
+                 "Hello, {}!\n", "world");
+      fmt::print(fg(fmt::color::floral_white) | bg(fmt::color::slate_gray) |
+                 fmt::emphasis::underline, "Hello, {}!\n", "мир");
+      fmt::print(fg(fmt::color::steel_blue) | fmt::emphasis::italic,
+                 "Hello, {}!\n", "世界");
     }
 
-    report_error("file not found: {}", path);
+Output on a modern terminal:
 
-Note that ``vreport_error`` is not parameterized on argument types which can
-improve compile times and reduce code size compared to a fully parameterized
-version.
+.. image:: https://user-images.githubusercontent.com/
+           576385/88485597-d312f600-cf2b-11ea-9cbe-61f535a86e28.png
 
 Benchmarks
 ----------
@@ -174,18 +195,20 @@ Folly Format      folly::format   2.23
 {fmt} is the fastest of the benchmarked methods, ~35% faster than ``printf``.
 
 The above results were generated by building ``tinyformat_test.cpp`` on macOS
-10.14.6 with ``clang++ -O3 -DSPEED_TEST -DHAVE_FORMAT``, and taking the best of
-three runs. In the test, the format string ``"%0.10f:%04d:%+g:%s:%p:%c:%%\n"``
+10.14.6 with ``clang++ -O3 -DNDEBUG -DSPEED_TEST -DHAVE_FORMAT``, and taking the
+best of three runs. In the test, the format string ``"%0.10f:%04d:%+g:%s:%p:%c:%%\n"``
 or equivalent is filled 2,000,000 times with output sent to ``/dev/null``; for
 further details refer to the `source
 <https://github.com/fmtlib/format-benchmark/blob/master/tinyformat_test.cpp>`_.
 
-{fmt} is 10x faster than ``std::ostringstream`` and ``sprintf`` on floating-point
-formatting (`dtoa-benchmark <https://github.com/fmtlib/dtoa-benchmark>`_)
-and as fast as `double-conversion <https://github.com/google/double-conversion>`_:
+{fmt} is up to 20-30x faster than ``std::ostringstream`` and ``sprintf`` on
+floating-point formatting (`dtoa-benchmark <https://github.com/fmtlib/dtoa-benchmark>`_)
+and faster than `double-conversion <https://github.com/google/double-conversion>`_ and
+`ryu <https://github.com/ulfjack/ryu>`_:
 
-.. image:: https://user-images.githubusercontent.com/576385/69767160-cdaca400-112f-11ea-9fc5-347c9f83caad.png
-   :target: https://fmt.dev/unknown_mac64_clang10.0.html
+.. image:: https://user-images.githubusercontent.com/576385/
+           95684665-11719600-0ba8-11eb-8e5b-972ff4e49428.png
+   :target: https://fmt.dev/unknown_mac64_clang12.0.html
 
 Compile time and code bloat
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~
@@ -264,86 +287,110 @@ or the bloat test::
 Projects using this library
 ---------------------------
 
-* `0 A.D. <http://play0ad.com/>`_: A free, open-source, cross-platform real-time
-  strategy game
+* `0 A.D. <https://play0ad.com/>`_: a free, open-source, cross-platform
+  real-time strategy game
 
 * `AMPL/MP <https://github.com/ampl/mp>`_:
-  An open-source library for mathematical programming
-  
-* `AvioBook <https://www.aviobook.aero/en>`_: A comprehensive aircraft
+  an open-source library for mathematical programming
+
+* `Aseprite <https://github.com/aseprite/aseprite>`_:
+  animated sprite editor & pixel art tool 
+
+* `AvioBook <https://www.aviobook.aero/en>`_: a comprehensive aircraft
   operations suite
   
-* `Celestia <https://celestia.space/>`_: Real-time 3D visualization of space
+* `Blizzard Battle.net <https://battle.net/>`_: an online gaming platform
+  
+* `Celestia <https://celestia.space/>`_: real-time 3D visualization of space
+
+* `Ceph <https://ceph.com/>`_: a scalable distributed storage system
 
-* `Ceph <https://ceph.com/>`_: A scalable distributed storage system
+* `ccache <https://ccache.dev/>`_: a compiler cache
 
-* `ccache <https://ccache.dev/>`_: A compiler cache
+* `ClickHouse <https://github.com/ClickHouse/ClickHouse>`_: analytical database
+  management system
 
 * `CUAUV <http://cuauv.org/>`_: Cornell University's autonomous underwater
   vehicle
 
-* `HarpyWar/pvpgn <https://github.com/pvpgn/pvpgn-server>`_:
-  Player vs Player Gaming Network with tweaks
+* `Drake <https://drake.mit.edu/>`_: a planning, control, and analysis toolbox
+  for nonlinear dynamical systems (MIT)
 
-* `KBEngine <http://kbengine.org/>`_: An open-source MMOG server engine
+* `Envoy <https://lyft.github.io/envoy/>`_: C++ L7 proxy and communication bus
+  (Lyft)
 
-* `Keypirinha <http://keypirinha.com/>`_: A semantic launcher for Windows
+* `FiveM <https://fivem.net/>`_: a modification framework for GTA V
 
-* `Kodi <https://kodi.tv/>`_ (formerly xbmc): Home theater software
+* `Folly <https://github.com/facebook/folly>`_: Facebook open-source library
 
-* `Lifeline <https://github.com/peter-clark/lifeline>`_: A 2D game
+* `HarpyWar/pvpgn <https://github.com/pvpgn/pvpgn-server>`_:
+  Player vs Player Gaming Network with tweaks
 
-* `Drake <http://drake.mit.edu/>`_: A planning, control, and analysis toolbox
-  for nonlinear dynamical systems (MIT)
+* `KBEngine <https://github.com/kbengine/kbengine>`_: an open-source MMOG server
+  engine
 
-* `Envoy <https://lyft.github.io/envoy/>`_: C++ L7 proxy and communication bus
-  (Lyft)
+* `Keypirinha <https://keypirinha.com/>`_: a semantic launcher for Windows
 
-* `FiveM <https://fivem.net/>`_: a modification framework for GTA V
+* `Kodi <https://kodi.tv/>`_ (formerly xbmc): home theater software
+
+* `Knuth <https://kth.cash/>`_: high-performance Bitcoin full-node
 
-* `MongoDB <https://mongodb.com/>`_: Distributed document database
+* `Microsoft Verona <https://github.com/microsoft/verona>`_:
+  research programming language for concurrent ownership
 
-* `MongoDB Smasher <https://github.com/duckie/mongo_smasher>`_: A small tool to
+* `MongoDB <https://mongodb.com/>`_: distributed document database
+
+* `MongoDB Smasher <https://github.com/duckie/mongo_smasher>`_: a small tool to
   generate randomized datasets
 
-* `OpenSpace <http://openspaceproject.com/>`_: An open-source astrovisualization
-  framework
+* `OpenSpace <https://openspaceproject.com/>`_: an open-source
+  astrovisualization framework
+
+* `PenUltima Online (POL) <https://www.polserver.com/>`_:
+  an MMO server, compatible with most Ultima Online clients
 
-* `PenUltima Online (POL) <http://www.polserver.com/>`_:
-  An MMO server, compatible with most Ultima Online clients
+* `PyTorch <https://github.com/pytorch/pytorch>`_: an open-source machine
+  learning library
 
-* `quasardb <https://www.quasardb.net/>`_: A distributed, high-performance,
+* `quasardb <https://www.quasardb.net/>`_: a distributed, high-performance,
   associative database
+  
+* `Quill <https://github.com/odygrd/quill>`_: asynchronous low-latency logging library
 
-* `readpe <https://bitbucket.org/sys_dev/readpe>`_: Read Portable Executable
+* `QKW <https://github.com/ravijanjam/qkw>`_: generalizing aliasing to simplify
+  navigation, and executing complex multi-line terminal command sequences
 
-* `redis-cerberus <https://github.com/HunanTV/redis-cerberus>`_: A Redis cluster
+* `redis-cerberus <https://github.com/HunanTV/redis-cerberus>`_: a Redis cluster
   proxy
 
-* `rpclib <http://rpclib.net/>`_: A modern C++ msgpack-RPC server and client
-  library
+* `redpanda <https://vectorized.io/redpanda>`_: a 10x faster Kafka® replacement
+  for mission critical systems written in C++
 
-* `Saddy <https://github.com/mamontov-cpp/saddy-graphics-engine-2d>`_:
-  Small crossplatform 2D graphic engine
+* `rpclib <http://rpclib.net/>`_: a modern C++ msgpack-RPC server and client
+  library
 
-* `Salesforce Analytics Cloud <http://www.salesforce.com/analytics-cloud/overview/>`_:
-  Business intelligence software
+* `Salesforce Analytics Cloud
+  <https://www.salesforce.com/analytics-cloud/overview/>`_:
+  business intelligence software
 
-* `Scylla <http://www.scylladb.com/>`_: A Cassandra-compatible NoSQL data store
+* `Scylla <https://www.scylladb.com/>`_: a Cassandra-compatible NoSQL data store
   that can handle 1 million transactions per second on a single server
 
-* `Seastar <http://www.seastar-project.org/>`_: An advanced, open-source C++
+* `Seastar <http://www.seastar-project.org/>`_: an advanced, open-source C++
   framework for high-performance server applications on modern hardware
 
-* `spdlog <https://github.com/gabime/spdlog>`_: Super fast C++ logging library
+* `spdlog <https://github.com/gabime/spdlog>`_: super fast C++ logging library
 
-* `Stellar <https://www.stellar.org/>`_: Financial platform
+* `Stellar <https://www.stellar.org/>`_: financial platform
 
-* `Touch Surgery <https://www.touchsurgery.com/>`_: Surgery simulator
+* `Touch Surgery <https://www.touchsurgery.com/>`_: surgery simulator
 
-* `TrinityCore <https://github.com/TrinityCore/TrinityCore>`_: Open-source
+* `TrinityCore <https://github.com/TrinityCore/TrinityCore>`_: open-source
   MMORPG framework
 
+* `Windows Terminal <https://github.com/microsoft/terminal>`_: the new Windows
+  terminal
+
 `More... <https://github.com/search?q=fmtlib&type=Code>`_
 
 If you are aware of other projects using this library, please let me know
@@ -368,7 +415,7 @@ The good thing about ``printf`` is that it is pretty fast and readily available
 being a part of the C standard library. The main drawback is that it
 doesn't support user-defined types. ``printf`` also has safety issues although
 they are somewhat mitigated with `__attribute__ ((format (printf, ...))
-<http://gcc.gnu.org/onlinedocs/gcc/Function-Attributes.html>`_ in GCC.
+<https://gcc.gnu.org/onlinedocs/gcc/Function-Attributes.html>`_ in GCC.
 There is a POSIX extension that adds positional arguments required for
 `i18n <https://en.wikipedia.org/wiki/Internationalization_and_localization>`_
 to ``printf`` but it is not a part of C99 and may not be available on some
@@ -400,15 +447,15 @@ Boost Format
 
 This is a very powerful library which supports both ``printf``-like format
 strings and positional arguments. Its main drawback is performance. According to
-various benchmarks it is much slower than other methods considered here. Boost
+various, benchmarks it is much slower than other methods considered here. Boost
 Format also has excessive build times and severe code bloat issues (see
 `Benchmarks`_).
 
 FastFormat
 ~~~~~~~~~~
 
-This is an interesting library which is fast, safe and has positional
-arguments. However it has significant limitations, citing its author:
+This is an interesting library which is fast, safe and has positional arguments.
+However, it has significant limitations, citing its author:
 
     Three features that have no hope of being accommodated within the
     current design are:
@@ -417,8 +464,8 @@ arguments. However it has significant limitations, citing its author:
     * Octal/hexadecimal encoding
     * Runtime width/alignment specification
 
-It is also quite big and has a heavy dependency, STLSoft, which might be
-too restrictive for using it in some projects.
+It is also quite big and has a heavy dependency, STLSoft, which might be too
+restrictive for using it in some projects.
 
 Boost Spirit.Karma
 ~~~~~~~~~~~~~~~~~~
@@ -426,32 +473,9 @@ Boost Spirit.Karma
 This is not really a formatting library but I decided to include it here for
 completeness. As iostreams, it suffers from the problem of mixing verbatim text
 with arguments. The library is pretty fast, but slower on integer formatting
-than ``fmt::format_int`` on Karma's own benchmark,
-see `Fast integer to string conversion in C++
-<http://zverovich.net/2013/09/07/integer-to-string-conversion-in-cplusplus.html>`_.
-
-FAQ
----
-
-Q: how can I capture formatting arguments and format them later?
-
-A: use ``std::tuple``:
-
-.. code:: c++
-
-   template <typename... Args>
-   auto capture(const Args&... args) {
-     return std::make_tuple(args...);
-   }
-
-   auto print_message = [](const auto&... args) {
-     fmt::print(args...);
-   };
-
-   // Capture and store arguments:
-   auto args = capture("{} {}", 42, "foo");
-   // Do formatting:
-   std::apply(print_message, args);
+than ``fmt::format_to`` with format string compilation on Karma's own benchmark,
+see `Converting a hundred million integers to strings per second
+<http://www.zverovich.net/2020/06/13/fast-int-to-string-revisited.html>`_.
 
 License
 -------
@@ -459,18 +483,19 @@ License
 {fmt} is distributed under the MIT `license
 <https://github.com/fmtlib/fmt/blob/master/LICENSE.rst>`_.
 
-The `Format String Syntax
-<https://fmt.dev/latest/syntax.html>`_
+Documentation License
+---------------------
+
+The `Format String Syntax <https://fmt.dev/latest/syntax.html>`_
 section in the documentation is based on the one from Python `string module
-documentation <https://docs.python.org/3/library/string.html#module-string>`_
-adapted for the current library. For this reason the documentation is
-distributed under the Python Software Foundation license available in
-`doc/python-license.txt
+documentation <https://docs.python.org/3/library/string.html#module-string>`_.
+For this reason the documentation is distributed under the Python Software
+Foundation license available in `doc/python-license.txt
 <https://raw.github.com/fmtlib/fmt/master/doc/python-license.txt>`_.
-It only applies if you distribute the documentation of fmt.
+It only applies if you distribute the documentation of {fmt}.
 
-Acknowledgments
----------------
+Maintainers
+-----------
 
 The {fmt} library is maintained by Victor Zverovich (`vitaut
 <https://github.com/vitaut>`_) and Jonathan Müller (`foonathan
@@ -479,23 +504,3 @@ See `Contributors <https://github.com/fmtlib/fmt/graphs/contributors>`_ and
 `Releases <https://github.com/fmtlib/fmt/releases>`_ for some of the names.
 Let us know if your contribution is not listed or mentioned incorrectly and
 we'll make it right.
-
-The benchmark section of this readme file and the performance tests are taken
-from the excellent `tinyformat <https://github.com/c42f/tinyformat>`_ library
-written by Chris Foster.  Boost Format library is acknowledged transitively
-since it had some influence on tinyformat.
-Some ideas used in the implementation are borrowed from `Loki
-<http://loki-lib.sourceforge.net/>`_ SafeFormat and `Diagnostic API
-<http://clang.llvm.org/doxygen/classclang_1_1Diagnostic.html>`_ in
-`Clang <http://clang.llvm.org/>`_.
-Format string syntax and the documentation are based on Python's `str.format
-<https://docs.python.org/3/library/stdtypes.html#str.format>`_.
-Thanks `Doug Turnbull <https://github.com/softwaredoug>`_ for his valuable
-comments and contribution to the design of the type-safe API and
-`Gregory Czajkowski <https://github.com/gcflymoto>`_ for implementing binary
-formatting. Thanks `Ruslan Baratov <https://github.com/ruslo>`_ for comprehensive
-`comparison of integer formatting algorithms <https://github.com/ruslo/int-dec-format-tests>`_
-and useful comments regarding performance, `Boris Kaul <https://github.com/localvoid>`_ for
-`C++ counting digits benchmark <https://github.com/localvoid/cxx-benchmark-count-digits>`_.
-Thanks to `CarterLi <https://github.com/CarterLi>`_ for contributing various
-improvements to the code.
diff --git a/Externals/fmt/include/fmt/chrono.h b/Externals/fmt/include/fmt/chrono.h
index ca4ed30ae69c..1a3b8d5e5cd8 100755
--- a/Externals/fmt/include/fmt/chrono.h
+++ b/Externals/fmt/include/fmt/chrono.h
@@ -8,14 +8,14 @@
 #ifndef FMT_CHRONO_H_
 #define FMT_CHRONO_H_
 
-#include "format.h"
-#include "locale.h"
-
 #include <chrono>
 #include <ctime>
 #include <locale>
 #include <sstream>
 
+#include "format.h"
+#include "locale.h"
+
 FMT_BEGIN_NAMESPACE
 
 // Enable safe chrono durations, unless explicitly disabled.
@@ -48,7 +48,7 @@ FMT_CONSTEXPR To lossless_integral_conversion(const From from, int& ec) {
     // From fits in To without any problem.
   } else {
     // From does not always fit in To, resort to a dynamic check.
-    if (from < T::min() || from > T::max()) {
+    if (from < (T::min)() || from > (T::max)()) {
       // outside range.
       ec = 1;
       return {};
@@ -72,43 +72,27 @@ FMT_CONSTEXPR To lossless_integral_conversion(const From from, int& ec) {
   static_assert(F::is_integer, "From must be integral");
   static_assert(T::is_integer, "To must be integral");
 
-  if (F::is_signed && !T::is_signed) {
+  if (detail::const_check(F::is_signed && !T::is_signed)) {
     // From may be negative, not allowed!
-    if (fmt::internal::is_negative(from)) {
+    if (fmt::detail::is_negative(from)) {
       ec = 1;
       return {};
     }
-
     // From is positive. Can it always fit in To?
-    if (F::digits <= T::digits) {
-      // yes, From always fits in To.
-    } else {
-      // from may not fit in To, we have to do a dynamic check
-      if (from > static_cast<From>(T::max())) {
-        ec = 1;
-        return {};
-      }
+    if (F::digits > T::digits &&
+        from > static_cast<From>(detail::max_value<To>())) {
+      ec = 1;
+      return {};
     }
   }
 
-  if (!F::is_signed && T::is_signed) {
-    // can from be held in To?
-    if (F::digits < T::digits) {
-      // yes, From always fits in To.
-    } else {
-      // from may not fit in To, we have to do a dynamic check
-      if (from > static_cast<From>(T::max())) {
-        // outside range.
-        ec = 1;
-        return {};
-      }
-    }
+  if (!F::is_signed && T::is_signed && F::digits >= T::digits &&
+      from > static_cast<From>(detail::max_value<To>())) {
+    ec = 1;
+    return {};
   }
-
-  // reaching here means all is ok for lossless conversion.
-  return static_cast<To>(from);
-
-}  // function
+  return static_cast<To>(from);  // Lossless conversion.
+}
 
 template <typename To, typename From,
           FMT_ENABLE_IF(std::is_same<From, To>::value)>
@@ -141,7 +125,7 @@ FMT_CONSTEXPR To safe_float_conversion(const From from, int& ec) {
 
   // catch the only happy case
   if (std::isfinite(from)) {
-    if (from >= T::lowest() && from <= T::max()) {
+    if (from >= T::lowest() && from <= (T::max)()) {
       return static_cast<To>(from);
     }
     // not within range.
@@ -190,17 +174,16 @@ To safe_duration_cast(std::chrono::duration<FromRep, FromPeriod> from,
   // safe conversion to IntermediateRep
   IntermediateRep count =
       lossless_integral_conversion<IntermediateRep>(from.count(), ec);
-  if (ec) {
-    return {};
-  }
+  if (ec) return {};
   // multiply with Factor::num without overflow or underflow
-  if (Factor::num != 1) {
-    const auto max1 = internal::max_value<IntermediateRep>() / Factor::num;
+  if (detail::const_check(Factor::num != 1)) {
+    const auto max1 = detail::max_value<IntermediateRep>() / Factor::num;
     if (count > max1) {
       ec = 1;
       return {};
     }
-    const auto min1 = std::numeric_limits<IntermediateRep>::min() / Factor::num;
+    const auto min1 =
+        (std::numeric_limits<IntermediateRep>::min)() / Factor::num;
     if (count < min1) {
       ec = 1;
       return {};
@@ -208,17 +191,9 @@ To safe_duration_cast(std::chrono::duration<FromRep, FromPeriod> from,
     count *= Factor::num;
   }
 
-  // this can't go wrong, right? den>0 is checked earlier.
-  if (Factor::den != 1) {
-    count /= Factor::den;
-  }
-  // convert to the to type, safely
-  using ToRep = typename To::rep;
-  const ToRep tocount = lossless_integral_conversion<ToRep>(count, ec);
-  if (ec) {
-    return {};
-  }
-  return To{tocount};
+  if (detail::const_check(Factor::den != 1)) count /= Factor::den;
+  auto tocount = lossless_integral_conversion<typename To::rep>(count, ec);
+  return ec ? To() : To(tocount);
 }
 
 /**
@@ -269,7 +244,7 @@ To safe_duration_cast(std::chrono::duration<FromRep, FromPeriod> from,
 
   // multiply with Factor::num without overflow or underflow
   if (Factor::num != 1) {
-    constexpr auto max1 = internal::max_value<IntermediateRep>() /
+    constexpr auto max1 = detail::max_value<IntermediateRep>() /
                           static_cast<IntermediateRep>(Factor::num);
     if (count > max1) {
       ec = 1;
@@ -306,12 +281,12 @@ To safe_duration_cast(std::chrono::duration<FromRep, FromPeriod> from,
 // Usage: f FMT_NOMACRO()
 #define FMT_NOMACRO
 
-namespace internal {
+namespace detail {
 inline null<> localtime_r FMT_NOMACRO(...) { return null<>(); }
 inline null<> localtime_s(...) { return null<>(); }
 inline null<> gmtime_r(...) { return null<>(); }
 inline null<> gmtime_s(...) { return null<>(); }
-}  // namespace internal
+}  // namespace detail
 
 // Thread-safe replacement for std::localtime
 inline std::tm localtime(std::time_t time) {
@@ -322,22 +297,22 @@ inline std::tm localtime(std::time_t time) {
     dispatcher(std::time_t t) : time_(t) {}
 
     bool run() {
-      using namespace fmt::internal;
+      using namespace fmt::detail;
       return handle(localtime_r(&time_, &tm_));
     }
 
     bool handle(std::tm* tm) { return tm != nullptr; }
 
-    bool handle(internal::null<>) {
-      using namespace fmt::internal;
+    bool handle(detail::null<>) {
+      using namespace fmt::detail;
       return fallback(localtime_s(&tm_, &time_));
     }
 
     bool fallback(int res) { return res == 0; }
 
 #if !FMT_MSC_VER
-    bool fallback(internal::null<>) {
-      using namespace fmt::internal;
+    bool fallback(detail::null<>) {
+      using namespace fmt::detail;
       std::tm* tm = std::localtime(&time_);
       if (tm) tm_ = *tm;
       return tm != nullptr;
@@ -350,6 +325,11 @@ inline std::tm localtime(std::time_t time) {
   return lt.tm_;
 }
 
+inline std::tm localtime(
+    std::chrono::time_point<std::chrono::system_clock> time_point) {
+  return localtime(std::chrono::system_clock::to_time_t(time_point));
+}
+
 // Thread-safe replacement for std::gmtime
 inline std::tm gmtime(std::time_t time) {
   struct dispatcher {
@@ -359,21 +339,21 @@ inline std::tm gmtime(std::time_t time) {
     dispatcher(std::time_t t) : time_(t) {}
 
     bool run() {
-      using namespace fmt::internal;
+      using namespace fmt::detail;
       return handle(gmtime_r(&time_, &tm_));
     }
 
     bool handle(std::tm* tm) { return tm != nullptr; }
 
-    bool handle(internal::null<>) {
-      using namespace fmt::internal;
+    bool handle(detail::null<>) {
+      using namespace fmt::detail;
       return fallback(gmtime_s(&tm_, &time_));
     }
 
     bool fallback(int res) { return res == 0; }
 
 #if !FMT_MSC_VER
-    bool fallback(internal::null<>) {
+    bool fallback(detail::null<>) {
       std::tm* tm = std::gmtime(&time_);
       if (tm) tm_ = *tm;
       return tm != nullptr;
@@ -386,17 +366,33 @@ inline std::tm gmtime(std::time_t time) {
   return gt.tm_;
 }
 
-namespace internal {
-inline std::size_t strftime(char* str, std::size_t count, const char* format,
-                            const std::tm* time) {
+inline std::tm gmtime(
+    std::chrono::time_point<std::chrono::system_clock> time_point) {
+  return gmtime(std::chrono::system_clock::to_time_t(time_point));
+}
+
+namespace detail {
+inline size_t strftime(char* str, size_t count, const char* format,
+                       const std::tm* time) {
   return std::strftime(str, count, format, time);
 }
 
-inline std::size_t strftime(wchar_t* str, std::size_t count,
-                            const wchar_t* format, const std::tm* time) {
+inline size_t strftime(wchar_t* str, size_t count, const wchar_t* format,
+                       const std::tm* time) {
   return std::wcsftime(str, count, format, time);
 }
-}  // namespace internal
+}  // namespace detail
+
+template <typename Char>
+struct formatter<std::chrono::time_point<std::chrono::system_clock>, Char>
+    : formatter<std::tm, Char> {
+  template <typename FormatContext>
+  auto format(std::chrono::time_point<std::chrono::system_clock> val,
+              FormatContext& ctx) -> decltype(ctx.out()) {
+    std::tm time = localtime(val);
+    return formatter<std::tm, Char>::format(time, ctx);
+  }
+};
 
 template <typename Char> struct formatter<std::tm, Char> {
   template <typename ParseContext>
@@ -405,7 +401,7 @@ template <typename Char> struct formatter<std::tm, Char> {
     if (it != ctx.end() && *it == ':') ++it;
     auto end = it;
     while (end != ctx.end() && *end != '}') ++end;
-    tm_format.reserve(internal::to_unsigned(end - it + 1));
+    tm_format.reserve(detail::to_unsigned(end - it + 1));
     tm_format.append(it, end);
     tm_format.push_back('\0');
     return end;
@@ -414,11 +410,10 @@ template <typename Char> struct formatter<std::tm, Char> {
   template <typename FormatContext>
   auto format(const std::tm& tm, FormatContext& ctx) -> decltype(ctx.out()) {
     basic_memory_buffer<Char> buf;
-    std::size_t start = buf.size();
+    size_t start = buf.size();
     for (;;) {
-      std::size_t size = buf.capacity() - start;
-      std::size_t count =
-          internal::strftime(&buf[start], size, &tm_format[0], &tm);
+      size_t size = buf.capacity() - start;
+      size_t count = detail::strftime(&buf[start], size, &tm_format[0], &tm);
       if (count != 0) {
         buf.resize(start + count);
         break;
@@ -430,7 +425,7 @@ template <typename Char> struct formatter<std::tm, Char> {
         // https://github.com/fmtlib/fmt/issues/367
         break;
       }
-      const std::size_t MIN_GROWTH = 10;
+      const size_t MIN_GROWTH = 10;
       buf.reserve(buf.capacity() + (size > MIN_GROWTH ? size : MIN_GROWTH));
     }
     return std::copy(buf.begin(), buf.end(), ctx.out());
@@ -439,7 +434,7 @@ template <typename Char> struct formatter<std::tm, Char> {
   basic_memory_buffer<Char> tm_format;
 };
 
-namespace internal {
+namespace detail {
 template <typename Period> FMT_CONSTEXPR const char* get_units() {
   return nullptr;
 }
@@ -495,12 +490,12 @@ FMT_CONSTEXPR const Char* parse_chrono_format(const Char* begin,
       handler.on_text(ptr - 1, ptr);
       break;
     case 'n': {
-      const char newline[] = "\n";
+      const Char newline[] = {'\n'};
       handler.on_text(newline, newline + 1);
       break;
     }
     case 't': {
-      const char tab[] = "\t";
+      const Char tab[] = {'\t'};
       handler.on_text(tab, tab + 1);
       break;
     }
@@ -759,18 +754,36 @@ inline std::chrono::duration<Rep, std::milli> get_milliseconds(
   return std::chrono::duration<Rep, std::milli>(static_cast<Rep>(ms));
 }
 
-template <typename Rep, typename OutputIt>
-OutputIt format_chrono_duration_value(OutputIt out, Rep val, int precision) {
-  if (precision >= 0) return format_to(out, "{:.{}f}", val, precision);
-  return format_to(out, std::is_floating_point<Rep>::value ? "{:g}" : "{}",
+template <typename Char, typename Rep, typename OutputIt>
+OutputIt format_duration_value(OutputIt out, Rep val, int precision) {
+  const Char pr_f[] = {'{', ':', '.', '{', '}', 'f', '}', 0};
+  if (precision >= 0) return format_to(out, pr_f, val, precision);
+  const Char fp_f[] = {'{', ':', 'g', '}', 0};
+  const Char format[] = {'{', '}', 0};
+  return format_to(out, std::is_floating_point<Rep>::value ? fp_f : format,
                    val);
 }
+template <typename Char, typename OutputIt>
+OutputIt copy_unit(string_view unit, OutputIt out, Char) {
+  return std::copy(unit.begin(), unit.end(), out);
+}
+
+template <typename OutputIt>
+OutputIt copy_unit(string_view unit, OutputIt out, wchar_t) {
+  // This works when wchar_t is UTF-32 because units only contain characters
+  // that have the same representation in UTF-16 and UTF-32.
+  utf8_to_utf16 u(unit);
+  return std::copy(u.c_str(), u.c_str() + u.size(), out);
+}
 
-template <typename Period, typename OutputIt>
-static OutputIt format_chrono_duration_unit(OutputIt out) {
-  if (const char* unit = get_units<Period>()) return format_to(out, "{}", unit);
-  if (Period::den == 1) return format_to(out, "[{}]s", Period::num);
-  return format_to(out, "[{}/{}]s", Period::num, Period::den);
+template <typename Char, typename Period, typename OutputIt>
+OutputIt format_duration_unit(OutputIt out) {
+  if (const char* unit = get_units<Period>())
+    return copy_unit(string_view(unit), out, Char());
+  const Char num_f[] = {'[', '{', '}', ']', 's', 0};
+  if (const_check(Period::den == 1)) return format_to(out, num_f, Period::num);
+  const Char num_def_f[] = {'[', '{', '}', '/', '{', '}', ']', 's', 0};
+  return format_to(out, num_def_f, Period::num, Period::den);
 }
 
 template <typename FormatContext, typename OutputIt, typename Rep,
@@ -862,22 +875,22 @@ struct chrono_formatter {
     if (isnan(value)) return write_nan();
     uint32_or_64_or_128_t<int> n =
         to_unsigned(to_nonnegative_int(value, max_value<int>()));
-    int num_digits = internal::count_digits(n);
+    int num_digits = detail::count_digits(n);
     if (width > num_digits) out = std::fill_n(out, width - num_digits, '0');
-    out = format_decimal<char_type>(out, n, num_digits);
+    out = format_decimal<char_type>(out, n, num_digits).end;
   }
 
   void write_nan() { std::copy_n("nan", 3, out); }
   void write_pinf() { std::copy_n("inf", 3, out); }
   void write_ninf() { std::copy_n("-inf", 4, out); }
 
-  void format_localized(const tm& time, const char* format) {
+  void format_localized(const tm& time, char format, char modifier = 0) {
     if (isnan(val)) return write_nan();
     auto locale = context.locale().template get<std::locale>();
     auto& facet = std::use_facet<std::time_put<char_type>>(locale);
     std::basic_ostringstream<char_type> os;
     os.imbue(locale);
-    facet.put(os, os, ' ', &time, format, format + std::strlen(format));
+    facet.put(os, os, ' ', &time, format, modifier);
     auto str = os.str();
     std::copy(str.begin(), str.end(), out);
   }
@@ -907,7 +920,7 @@ struct chrono_formatter {
     if (ns == numeric_system::standard) return write(hour(), 2);
     auto time = tm();
     time.tm_hour = to_nonnegative_int(hour(), 24);
-    format_localized(time, "%OH");
+    format_localized(time, 'H', 'O');
   }
 
   void on_12_hour(numeric_system ns) {
@@ -916,7 +929,7 @@ struct chrono_formatter {
     if (ns == numeric_system::standard) return write(hour12(), 2);
     auto time = tm();
     time.tm_hour = to_nonnegative_int(hour12(), 12);
-    format_localized(time, "%OI");
+    format_localized(time, 'I', 'O');
   }
 
   void on_minute(numeric_system ns) {
@@ -925,7 +938,7 @@ struct chrono_formatter {
     if (ns == numeric_system::standard) return write(minute(), 2);
     auto time = tm();
     time.tm_min = to_nonnegative_int(minute(), 60);
-    format_localized(time, "%OM");
+    format_localized(time, 'M', 'O');
   }
 
   void on_second(numeric_system ns) {
@@ -950,13 +963,12 @@ struct chrono_formatter {
     }
     auto time = tm();
     time.tm_sec = to_nonnegative_int(second(), 60);
-    format_localized(time, "%OS");
+    format_localized(time, 'S', 'O');
   }
 
   void on_12_hour_time() {
     if (handle_nan_inf()) return;
-
-    format_localized(time(), "%r");
+    format_localized(time(), 'r');
   }
 
   void on_24_hour_time() {
@@ -980,25 +992,27 @@ struct chrono_formatter {
 
   void on_am_pm() {
     if (handle_nan_inf()) return;
-    format_localized(time(), "%p");
+    format_localized(time(), 'p');
   }
 
   void on_duration_value() {
     if (handle_nan_inf()) return;
     write_sign();
-    out = format_chrono_duration_value(out, val, precision);
+    out = format_duration_value<char_type>(out, val, precision);
   }
 
-  void on_duration_unit() { out = format_chrono_duration_unit<Period>(out); }
+  void on_duration_unit() {
+    out = format_duration_unit<char_type, Period>(out);
+  }
 };
-}  // namespace internal
+}  // namespace detail
 
 template <typename Rep, typename Period, typename Char>
 struct formatter<std::chrono::duration<Rep, Period>, Char> {
  private:
   basic_format_specs<Char> specs;
   int precision;
-  using arg_ref_type = internal::arg_ref<Char>;
+  using arg_ref_type = detail::arg_ref<Char>;
   arg_ref_type width_ref;
   arg_ref_type precision_ref;
   mutable basic_string_view<Char> format_str;
@@ -1019,12 +1033,12 @@ struct formatter<std::chrono::duration<Rep, Period>, Char> {
       return arg_ref_type(arg_id);
     }
 
-    FMT_CONSTEXPR arg_ref_type make_arg_ref(internal::auto_id) {
+    FMT_CONSTEXPR arg_ref_type make_arg_ref(detail::auto_id) {
       return arg_ref_type(context.next_arg_id());
     }
 
     void on_error(const char* msg) { FMT_THROW(format_error(msg)); }
-    void on_fill(Char fill) { f.specs.fill[0] = fill; }
+    void on_fill(basic_string_view<Char> fill) { f.specs.fill = fill; }
     void on_align(align_t align) { f.specs.align = align; }
     void on_width(int width) { f.specs.width = width; }
     void on_precision(int _precision) { f.precision = _precision; }
@@ -1049,17 +1063,17 @@ struct formatter<std::chrono::duration<Rep, Period>, Char> {
     auto begin = ctx.begin(), end = ctx.end();
     if (begin == end || *begin == '}') return {begin, begin};
     spec_handler handler{*this, ctx, format_str};
-    begin = internal::parse_align(begin, end, handler);
+    begin = detail::parse_align(begin, end, handler);
     if (begin == end) return {begin, begin};
-    begin = internal::parse_width(begin, end, handler);
+    begin = detail::parse_width(begin, end, handler);
     if (begin == end) return {begin, begin};
     if (*begin == '.') {
       if (std::is_floating_point<Rep>::value)
-        begin = internal::parse_precision(begin, end, handler);
+        begin = detail::parse_precision(begin, end, handler);
       else
         handler.on_error("precision not allowed for this argument type");
     }
-    end = parse_chrono_format(begin, end, internal::chrono_format_checker());
+    end = parse_chrono_format(begin, end, detail::chrono_format_checker());
     return {begin, end};
   }
 
@@ -1070,7 +1084,7 @@ struct formatter<std::chrono::duration<Rep, Period>, Char> {
       -> decltype(ctx.begin()) {
     auto range = do_parse(ctx);
     format_str = basic_string_view<Char>(
-        &*range.begin, internal::to_unsigned(range.end - range.begin));
+        &*range.begin, detail::to_unsigned(range.end - range.begin));
     return range.end;
   }
 
@@ -1081,23 +1095,21 @@ struct formatter<std::chrono::duration<Rep, Period>, Char> {
     // is not specified.
     basic_memory_buffer<Char> buf;
     auto out = std::back_inserter(buf);
-    using range = internal::output_range<decltype(ctx.out()), Char>;
-    internal::basic_writer<range> w(range(ctx.out()));
-    internal::handle_dynamic_spec<internal::width_checker>(specs.width,
-                                                           width_ref, ctx);
-    internal::handle_dynamic_spec<internal::precision_checker>(
-        precision, precision_ref, ctx);
+    detail::handle_dynamic_spec<detail::width_checker>(specs.width, width_ref,
+                                                       ctx);
+    detail::handle_dynamic_spec<detail::precision_checker>(precision,
+                                                           precision_ref, ctx);
     if (begin == end || *begin == '}') {
-      out = internal::format_chrono_duration_value(out, d.count(), precision);
-      internal::format_chrono_duration_unit<Period>(out);
+      out = detail::format_duration_value<Char>(out, d.count(), precision);
+      detail::format_duration_unit<Char, Period>(out);
     } else {
-      internal::chrono_formatter<FormatContext, decltype(out), Rep, Period> f(
+      detail::chrono_formatter<FormatContext, decltype(out), Rep, Period> f(
           ctx, out, d);
       f.precision = precision;
       parse_chrono_format(begin, end, f);
     }
-    w.write(buf.data(), buf.size(), specs);
-    return w.out();
+    return detail::write(
+        ctx.out(), basic_string_view<Char>(buf.data(), buf.size()), specs);
   }
 };
 
diff --git a/Externals/fmt/include/fmt/color.h b/Externals/fmt/include/fmt/color.h
index 362a95e142e7..789105895091 100755
--- a/Externals/fmt/include/fmt/color.h
+++ b/Externals/fmt/include/fmt/color.h
@@ -198,7 +198,7 @@ struct rgb {
   uint8_t b;
 };
 
-namespace internal {
+namespace detail {
 
 // color is a struct of either a rgb color or a terminal color.
 struct color_type {
@@ -221,7 +221,7 @@ struct color_type {
     uint32_t rgb_color;
   } value;
 };
-}  // namespace internal
+}  // namespace detail
 
 // Experimental text formatting support.
 class text_style {
@@ -298,11 +298,11 @@ class text_style {
   FMT_CONSTEXPR bool has_emphasis() const FMT_NOEXCEPT {
     return static_cast<uint8_t>(ems) != 0;
   }
-  FMT_CONSTEXPR internal::color_type get_foreground() const FMT_NOEXCEPT {
+  FMT_CONSTEXPR detail::color_type get_foreground() const FMT_NOEXCEPT {
     FMT_ASSERT(has_foreground(), "no foreground specified for this style");
     return foreground_color;
   }
-  FMT_CONSTEXPR internal::color_type get_background() const FMT_NOEXCEPT {
+  FMT_CONSTEXPR detail::color_type get_background() const FMT_NOEXCEPT {
     FMT_ASSERT(has_background(), "no background specified for this style");
     return background_color;
   }
@@ -313,7 +313,7 @@ class text_style {
 
  private:
   FMT_CONSTEXPR text_style(bool is_foreground,
-                           internal::color_type text_color) FMT_NOEXCEPT
+                           detail::color_type text_color) FMT_NOEXCEPT
       : set_foreground_color(),
         set_background_color(),
         ems() {
@@ -326,23 +326,23 @@ class text_style {
     }
   }
 
-  friend FMT_CONSTEXPR_DECL text_style fg(internal::color_type foreground)
+  friend FMT_CONSTEXPR_DECL text_style fg(detail::color_type foreground)
       FMT_NOEXCEPT;
-  friend FMT_CONSTEXPR_DECL text_style bg(internal::color_type background)
+  friend FMT_CONSTEXPR_DECL text_style bg(detail::color_type background)
       FMT_NOEXCEPT;
 
-  internal::color_type foreground_color;
-  internal::color_type background_color;
+  detail::color_type foreground_color;
+  detail::color_type background_color;
   bool set_foreground_color;
   bool set_background_color;
   emphasis ems;
 };
 
-FMT_CONSTEXPR text_style fg(internal::color_type foreground) FMT_NOEXCEPT {
+FMT_CONSTEXPR text_style fg(detail::color_type foreground) FMT_NOEXCEPT {
   return text_style(/*is_foreground=*/true, foreground);
 }
 
-FMT_CONSTEXPR text_style bg(internal::color_type background) FMT_NOEXCEPT {
+FMT_CONSTEXPR text_style bg(detail::color_type background) FMT_NOEXCEPT {
   return text_style(/*is_foreground=*/false, background);
 }
 
@@ -350,21 +350,21 @@ FMT_CONSTEXPR text_style operator|(emphasis lhs, emphasis rhs) FMT_NOEXCEPT {
   return text_style(lhs) | rhs;
 }
 
-namespace internal {
+namespace detail {
 
 template <typename Char> struct ansi_color_escape {
-  FMT_CONSTEXPR ansi_color_escape(internal::color_type text_color,
+  FMT_CONSTEXPR ansi_color_escape(detail::color_type text_color,
                                   const char* esc) FMT_NOEXCEPT {
     // If we have a terminal color, we need to output another escape code
     // sequence.
     if (!text_color.is_rgb) {
-      bool is_background = esc == internal::data::background_color;
+      bool is_background = esc == detail::data::background_color;
       uint32_t value = text_color.value.term_color;
       // Background ASCII codes are the same as the foreground ones but with
       // 10 more.
       if (is_background) value += 10u;
 
-      std::size_t index = 0;
+      size_t index = 0;
       buffer[index++] = static_cast<Char>('\x1b');
       buffer[index++] = static_cast<Char>('[');
 
@@ -398,7 +398,7 @@ template <typename Char> struct ansi_color_escape {
     if (em_bits & static_cast<uint8_t>(emphasis::strikethrough))
       em_codes[3] = 9;
 
-    std::size_t index = 0;
+    size_t index = 0;
     for (int i = 0; i < 4; ++i) {
       if (!em_codes[i]) continue;
       buffer[index++] = static_cast<Char>('\x1b');
@@ -412,7 +412,7 @@ template <typename Char> struct ansi_color_escape {
 
   FMT_CONSTEXPR const Char* begin() const FMT_NOEXCEPT { return buffer; }
   FMT_CONSTEXPR const Char* end() const FMT_NOEXCEPT {
-    return buffer + std::strlen(buffer);
+    return buffer + std::char_traits<Char>::length(buffer);
   }
 
  private:
@@ -429,14 +429,14 @@ template <typename Char> struct ansi_color_escape {
 
 template <typename Char>
 FMT_CONSTEXPR ansi_color_escape<Char> make_foreground_color(
-    internal::color_type foreground) FMT_NOEXCEPT {
-  return ansi_color_escape<Char>(foreground, internal::data::foreground_color);
+    detail::color_type foreground) FMT_NOEXCEPT {
+  return ansi_color_escape<Char>(foreground, detail::data::foreground_color);
 }
 
 template <typename Char>
 FMT_CONSTEXPR ansi_color_escape<Char> make_background_color(
-    internal::color_type background) FMT_NOEXCEPT {
-  return ansi_color_escape<Char>(background, internal::data::background_color);
+    detail::color_type background) FMT_NOEXCEPT {
+  return ansi_color_escape<Char>(background, detail::data::background_color);
 }
 
 template <typename Char>
@@ -455,73 +455,71 @@ inline void fputs<wchar_t>(const wchar_t* chars, FILE* stream) FMT_NOEXCEPT {
 }
 
 template <typename Char> inline void reset_color(FILE* stream) FMT_NOEXCEPT {
-  fputs(internal::data::reset_color, stream);
+  fputs(detail::data::reset_color, stream);
 }
 
 template <> inline void reset_color<wchar_t>(FILE* stream) FMT_NOEXCEPT {
-  fputs(internal::data::wreset_color, stream);
+  fputs(detail::data::wreset_color, stream);
 }
 
 template <typename Char>
-inline void reset_color(basic_memory_buffer<Char>& buffer) FMT_NOEXCEPT {
+inline void reset_color(buffer<Char>& buffer) FMT_NOEXCEPT {
   const char* begin = data::reset_color;
   const char* end = begin + sizeof(data::reset_color) - 1;
   buffer.append(begin, end);
 }
 
 template <typename Char>
-void vformat_to(basic_memory_buffer<Char>& buf, const text_style& ts,
+void vformat_to(buffer<Char>& buf, const text_style& ts,
                 basic_string_view<Char> format_str,
-                basic_format_args<buffer_context<Char>> args) {
+                basic_format_args<buffer_context<type_identity_t<Char>>> args) {
   bool has_style = false;
   if (ts.has_emphasis()) {
     has_style = true;
-    auto emphasis = internal::make_emphasis<Char>(ts.get_emphasis());
+    auto emphasis = detail::make_emphasis<Char>(ts.get_emphasis());
     buf.append(emphasis.begin(), emphasis.end());
   }
   if (ts.has_foreground()) {
     has_style = true;
-    auto foreground =
-        internal::make_foreground_color<Char>(ts.get_foreground());
+    auto foreground = detail::make_foreground_color<Char>(ts.get_foreground());
     buf.append(foreground.begin(), foreground.end());
   }
   if (ts.has_background()) {
     has_style = true;
-    auto background =
-        internal::make_background_color<Char>(ts.get_background());
+    auto background = detail::make_background_color<Char>(ts.get_background());
     buf.append(background.begin(), background.end());
   }
-  vformat_to(buf, format_str, args);
-  if (has_style) {
-    internal::reset_color<Char>(buf);
-  }
+  detail::vformat_to(buf, format_str, args);
+  if (has_style) detail::reset_color<Char>(buf);
 }
-}  // namespace internal
+}  // namespace detail
 
 template <typename S, typename Char = char_t<S>>
 void vprint(std::FILE* f, const text_style& ts, const S& format,
-            basic_format_args<buffer_context<Char>> args) {
+            basic_format_args<buffer_context<type_identity_t<Char>>> args) {
   basic_memory_buffer<Char> buf;
-  internal::vformat_to(buf, ts, to_string_view(format), args);
+  detail::vformat_to(buf, ts, to_string_view(format), args);
   buf.push_back(Char(0));
-  internal::fputs(buf.data(), f);
+  detail::fputs(buf.data(), f);
 }
 
 /**
+  \rst
   Formats a string and prints it to the specified file stream using ANSI
   escape sequences to specify text formatting.
-  Example:
+
+  **Example**::
+
     fmt::print(fmt::emphasis::bold | fg(fmt::color::red),
                "Elapsed time: {0:.2f} seconds", 1.23);
+  \endrst
  */
 template <typename S, typename... Args,
-          FMT_ENABLE_IF(internal::is_string<S>::value)>
+          FMT_ENABLE_IF(detail::is_string<S>::value)>
 void print(std::FILE* f, const text_style& ts, const S& format_str,
            const Args&... args) {
-  internal::check_format_string<Args...>(format_str);
-  using context = buffer_context<char_t<S>>;
-  format_arg_store<context, Args...> as{args...};
-  vprint(f, ts, format_str, basic_format_args<context>(as));
+  vprint(f, ts, format_str,
+         fmt::make_args_checked<Args...>(format_str, args...));
 }
 
 /**
@@ -532,7 +530,7 @@ void print(std::FILE* f, const text_style& ts, const S& format_str,
                "Elapsed time: {0:.2f} seconds", 1.23);
  */
 template <typename S, typename... Args,
-          FMT_ENABLE_IF(internal::is_string<S>::value)>
+          FMT_ENABLE_IF(detail::is_string<S>::value)>
 void print(const text_style& ts, const S& format_str, const Args&... args) {
   return print(stdout, ts, format_str, args...);
 }
@@ -540,9 +538,9 @@ void print(const text_style& ts, const S& format_str, const Args&... args) {
 template <typename S, typename Char = char_t<S>>
 inline std::basic_string<Char> vformat(
     const text_style& ts, const S& format_str,
-    basic_format_args<buffer_context<Char>> args) {
+    basic_format_args<buffer_context<type_identity_t<Char>>> args) {
   basic_memory_buffer<Char> buf;
-  internal::vformat_to(buf, ts, to_string_view(format_str), args);
+  detail::vformat_to(buf, ts, to_string_view(format_str), args);
   return fmt::to_string(buf);
 }
 
@@ -562,7 +560,41 @@ template <typename S, typename... Args, typename Char = char_t<S>>
 inline std::basic_string<Char> format(const text_style& ts, const S& format_str,
                                       const Args&... args) {
   return vformat(ts, to_string_view(format_str),
-                 {internal::make_args_checked<Args...>(format_str, args...)});
+                 fmt::make_args_checked<Args...>(format_str, args...));
+}
+
+/**
+  Formats a string with the given text_style and writes the output to ``out``.
+ */
+template <typename OutputIt, typename Char,
+          FMT_ENABLE_IF(detail::is_output_iterator<OutputIt, Char>::value)>
+OutputIt vformat_to(
+    OutputIt out, const text_style& ts, basic_string_view<Char> format_str,
+    basic_format_args<buffer_context<type_identity_t<Char>>> args) {
+  decltype(detail::get_buffer<Char>(out)) buf(detail::get_buffer_init(out));
+  detail::vformat_to(buf, ts, format_str, args);
+  return detail::get_iterator(buf);
+}
+
+/**
+  \rst
+  Formats arguments with the given text_style, writes the result to the output
+  iterator ``out`` and returns the iterator past the end of the output range.
+
+  **Example**::
+
+    std::vector<char> out;
+    fmt::format_to(std::back_inserter(out),
+                   fmt::emphasis::bold | fg(fmt::color::red), "{}", 42);
+  \endrst
+*/
+template <typename OutputIt, typename S, typename... Args,
+          FMT_ENABLE_IF(detail::is_output_iterator<OutputIt, char_t<S>>::value&&
+                            detail::is_string<S>::value)>
+inline OutputIt format_to(OutputIt out, const text_style& ts,
+                          const S& format_str, Args&&... args) {
+  return vformat_to(out, ts, to_string_view(format_str),
+                    fmt::make_args_checked<Args...>(format_str, args...));
 }
 
 FMT_END_NAMESPACE
diff --git a/Externals/fmt/include/fmt/compile.h b/Externals/fmt/include/fmt/compile.h
index 5829f623f10b..7db610d90f0e 100644
--- a/Externals/fmt/include/fmt/compile.h
+++ b/Externals/fmt/include/fmt/compile.h
@@ -9,10 +9,37 @@
 #define FMT_COMPILE_H_
 
 #include <vector>
+
 #include "format.h"
 
 FMT_BEGIN_NAMESPACE
-namespace internal {
+namespace detail {
+
+// A compile-time string which is compiled into fast formatting code.
+class compiled_string {};
+
+template <typename S>
+struct is_compiled_string : std::is_base_of<compiled_string, S> {};
+
+/**
+  \rst
+  Converts a string literal *s* into a format string that will be parsed at
+  compile time and converted into efficient formatting code. Requires C++17
+  ``constexpr if`` compiler support.
+
+  **Example**::
+
+    // Converts 42 into std::string using the most efficient method and no
+    // runtime format string processing.
+    std::string s = fmt::format(FMT_COMPILE("{}"), 42);
+  \endrst
+ */
+#define FMT_COMPILE(s) FMT_STRING_IMPL(s, fmt::detail::compiled_string)
+
+template <typename T, typename... Tail>
+const T& first(const T& value, const Tail&...) {
+  return value;
+}
 
 // Part of a compiled format string. It can be either literal text or a
 // replacement field.
@@ -61,13 +88,15 @@ template <typename Char> struct part_counter {
     if (begin != end) ++num_parts;
   }
 
-  FMT_CONSTEXPR void on_arg_id() { ++num_parts; }
-  FMT_CONSTEXPR void on_arg_id(int) { ++num_parts; }
-  FMT_CONSTEXPR void on_arg_id(basic_string_view<Char>) { ++num_parts; }
+  FMT_CONSTEXPR int on_arg_id() { return ++num_parts, 0; }
+  FMT_CONSTEXPR int on_arg_id(int) { return ++num_parts, 0; }
+  FMT_CONSTEXPR int on_arg_id(basic_string_view<Char>) {
+    return ++num_parts, 0;
+  }
 
-  FMT_CONSTEXPR void on_replacement_field(const Char*) {}
+  FMT_CONSTEXPR void on_replacement_field(int, const Char*) {}
 
-  FMT_CONSTEXPR const Char* on_format_specs(const Char* begin,
+  FMT_CONSTEXPR const Char* on_format_specs(int, const Char* begin,
                                             const Char* end) {
     // Find the matching brace.
     unsigned brace_counter = 0;
@@ -115,25 +144,28 @@ class format_string_compiler : public error_handler {
       handler_(part::make_text({begin, to_unsigned(end - begin)}));
   }
 
-  FMT_CONSTEXPR void on_arg_id() {
+  FMT_CONSTEXPR int on_arg_id() {
     part_ = part::make_arg_index(parse_context_.next_arg_id());
+    return 0;
   }
 
-  FMT_CONSTEXPR void on_arg_id(int id) {
+  FMT_CONSTEXPR int on_arg_id(int id) {
     parse_context_.check_arg_id(id);
     part_ = part::make_arg_index(id);
+    return 0;
   }
 
-  FMT_CONSTEXPR void on_arg_id(basic_string_view<Char> id) {
+  FMT_CONSTEXPR int on_arg_id(basic_string_view<Char> id) {
     part_ = part::make_arg_name(id);
+    return 0;
   }
 
-  FMT_CONSTEXPR void on_replacement_field(const Char* ptr) {
+  FMT_CONSTEXPR void on_replacement_field(int, const Char* ptr) {
     part_.arg_id_end = ptr;
     handler_(part_);
   }
 
-  FMT_CONSTEXPR const Char* on_format_specs(const Char* begin,
+  FMT_CONSTEXPR const Char* on_format_specs(int, const Char* begin,
                                             const Char* end) {
     auto repl = typename part::replacement();
     dynamic_specs_handler<basic_format_parse_context<Char>> handler(
@@ -159,23 +191,24 @@ FMT_CONSTEXPR void compile_format_string(basic_string_view<Char> format_str,
       format_string_compiler<Char, PartHandler>(format_str, handler));
 }
 
-template <typename Range, typename Context, typename Id>
+template <typename OutputIt, typename Context, typename Id>
 void format_arg(
-    basic_format_parse_context<typename Range::value_type>& parse_ctx,
+    basic_format_parse_context<typename Context::char_type>& parse_ctx,
     Context& ctx, Id arg_id) {
-  ctx.advance_to(
-      visit_format_arg(arg_formatter<Range>(ctx, &parse_ctx), ctx.arg(arg_id)));
+  ctx.advance_to(visit_format_arg(
+      arg_formatter<OutputIt, typename Context::char_type>(ctx, &parse_ctx),
+      ctx.arg(arg_id)));
 }
 
 // vformat_to is defined in a subnamespace to prevent ADL.
 namespace cf {
-template <typename Context, typename Range, typename CompiledFormat>
-auto vformat_to(Range out, CompiledFormat& cf, basic_format_args<Context> args)
-    -> typename Context::iterator {
+template <typename Context, typename OutputIt, typename CompiledFormat>
+auto vformat_to(OutputIt out, CompiledFormat& cf,
+                basic_format_args<Context> args) -> typename Context::iterator {
   using char_type = typename Context::char_type;
   basic_format_parse_context<char_type> parse_ctx(
       to_string_view(cf.format_str_));
-  Context ctx(out.begin(), args);
+  Context ctx(out, args);
 
   const auto& parts = cf.parts();
   for (auto part_it = std::begin(parts); part_it != std::end(parts);
@@ -196,12 +229,12 @@ auto vformat_to(Range out, CompiledFormat& cf, basic_format_args<Context> args)
 
     case format_part_t::kind::arg_index:
       advance_to(parse_ctx, part.arg_id_end);
-      internal::format_arg<Range>(parse_ctx, ctx, value.arg_index);
+      detail::format_arg<OutputIt>(parse_ctx, ctx, value.arg_index);
       break;
 
     case format_part_t::kind::arg_name:
       advance_to(parse_ctx, part.arg_id_end);
-      internal::format_arg<Range>(parse_ctx, ctx, value.str);
+      detail::format_arg<OutputIt>(parse_ctx, ctx, value.str);
       break;
 
     case format_part_t::kind::replacement: {
@@ -225,7 +258,9 @@ auto vformat_to(Range out, CompiledFormat& cf, basic_format_args<Context> args)
 
       advance_to(parse_ctx, part.arg_id_end);
       ctx.advance_to(
-          visit_format_arg(arg_formatter<Range>(ctx, nullptr, &specs), arg));
+          visit_format_arg(arg_formatter<OutputIt, typename Context::char_type>(
+                               ctx, nullptr, &specs),
+                           arg));
       break;
     }
     }
@@ -239,7 +274,7 @@ struct basic_compiled_format {};
 template <typename S, typename = void>
 struct compiled_format_base : basic_compiled_format {
   using char_type = char_t<S>;
-  using parts_container = std::vector<internal::format_part<char_type>>;
+  using parts_container = std::vector<detail::format_part<char_type>>;
 
   parts_container compiled_parts;
 
@@ -304,7 +339,7 @@ struct compiled_format_base<S, enable_if_t<is_compile_string<S>::value>>
   const parts_container& parts() const {
     static FMT_CONSTEXPR_DECL const auto compiled_parts =
         compile_to_parts<char_type, num_format_parts>(
-            internal::to_string_view(S()));
+            detail::to_string_view(S()));
     return compiled_parts.data;
   }
 };
@@ -317,8 +352,8 @@ class compiled_format : private compiled_format_base<S> {
  private:
   basic_string_view<char_type> format_str_;
 
-  template <typename Context, typename Range, typename CompiledFormat>
-  friend auto cf::vformat_to(Range out, CompiledFormat& cf,
+  template <typename Context, typename OutputIt, typename CompiledFormat>
+  friend auto cf::vformat_to(OutputIt out, CompiledFormat& cf,
                              basic_format_args<Context> args) ->
       typename Context::iterator;
 
@@ -333,7 +368,8 @@ template <typename... Args> struct type_list {};
 
 // Returns a reference to the argument at index N from [first, rest...].
 template <int N, typename T, typename... Args>
-constexpr const auto& get(const T& first, const Args&... rest) {
+constexpr const auto& get([[maybe_unused]] const T& first,
+                          [[maybe_unused]] const Args&... rest) {
   static_assert(N < 1 + sizeof...(Args), "index is out of bounds");
   if constexpr (N == 0)
     return first;
@@ -350,49 +386,39 @@ template <int N, typename... Args> struct get_type_impl<N, type_list<Args...>> {
 template <int N, typename T>
 using get_type = typename get_type_impl<N, T>::type;
 
+template <typename T> struct is_compiled_format : std::false_type {};
+
 template <typename Char> struct text {
   basic_string_view<Char> data;
   using char_type = Char;
 
   template <typename OutputIt, typename... Args>
   OutputIt format(OutputIt out, const Args&...) const {
-    // TODO: reserve
-    return copy_str<Char>(data.begin(), data.end(), out);
+    return write<Char>(out, data);
   }
 };
 
+template <typename Char>
+struct is_compiled_format<text<Char>> : std::true_type {};
+
 template <typename Char>
 constexpr text<Char> make_text(basic_string_view<Char> s, size_t pos,
                                size_t size) {
   return {{&s[pos], size}};
 }
 
-template <typename Char, typename OutputIt, typename T,
-          std::enable_if_t<std::is_integral_v<T>, int> = 0>
-OutputIt format_default(OutputIt out, T value) {
-  // TODO: reserve
-  format_int fi(value);
-  return std::copy(fi.data(), fi.data() + fi.size(), out);
-}
-
-template <typename Char, typename OutputIt>
-OutputIt format_default(OutputIt out, double value) {
-  writer w(out);
-  w.write(value);
-  return w.out();
-}
+template <typename Char> struct code_unit {
+  Char value;
+  using char_type = Char;
 
-template <typename Char, typename OutputIt>
-OutputIt format_default(OutputIt out, Char value) {
-  *out++ = value;
-  return out;
-}
+  template <typename OutputIt, typename... Args>
+  OutputIt format(OutputIt out, const Args&...) const {
+    return write<Char>(out, value);
+  }
+};
 
-template <typename Char, typename OutputIt>
-OutputIt format_default(OutputIt out, const Char* value) {
-  auto length = std::char_traits<Char>::length(value);
-  return copy_str<Char>(value, value + length, out);
-}
+template <typename Char>
+struct is_compiled_format<code_unit<Char>> : std::true_type {};
 
 // A replacement field that refers to argument N.
 template <typename Char, typename T, int N> struct field {
@@ -402,10 +428,32 @@ template <typename Char, typename T, int N> struct field {
   OutputIt format(OutputIt out, const Args&... args) const {
     // This ensures that the argument type is convertile to `const T&`.
     const T& arg = get<N>(args...);
-    return format_default<Char>(out, arg);
+    return write<Char>(out, arg);
   }
 };
 
+template <typename Char, typename T, int N>
+struct is_compiled_format<field<Char, T, N>> : std::true_type {};
+
+// A replacement field that refers to argument N and has format specifiers.
+template <typename Char, typename T, int N> struct spec_field {
+  using char_type = Char;
+  mutable formatter<T, Char> fmt;
+
+  template <typename OutputIt, typename... Args>
+  OutputIt format(OutputIt out, const Args&... args) const {
+    // This ensures that the argument type is convertile to `const T&`.
+    const T& arg = get<N>(args...);
+    const auto& vargs =
+        make_format_args<basic_format_context<OutputIt, Char>>(args...);
+    basic_format_context<OutputIt, Char> ctx(out, vargs);
+    return fmt.format(arg, ctx);
+  }
+};
+
+template <typename Char, typename T, int N>
+struct is_compiled_format<spec_field<Char, T, N>> : std::true_type {};
+
 template <typename L, typename R> struct concat {
   L lhs;
   R rhs;
@@ -418,6 +466,9 @@ template <typename L, typename R> struct concat {
   }
 };
 
+template <typename L, typename R>
+struct is_compiled_format<concat<L, R>> : std::true_type {};
+
 template <typename L, typename R>
 constexpr concat<L, R> make_concat(L lhs, R rhs) {
   return {lhs, rhs};
@@ -438,7 +489,8 @@ constexpr auto compile_format_string(S format_str);
 
 template <typename Args, size_t POS, int ID, typename T, typename S>
 constexpr auto parse_tail(T head, S format_str) {
-  if constexpr (POS != to_string_view(format_str).size()) {
+  if constexpr (POS !=
+                basic_string_view<typename S::char_type>(format_str).size()) {
     constexpr auto tail = compile_format_string<Args, POS, ID>(format_str);
     if constexpr (std::is_same<remove_cvref_t<decltype(tail)>,
                                unknown_format>())
@@ -450,6 +502,22 @@ constexpr auto parse_tail(T head, S format_str) {
   }
 }
 
+template <typename T, typename Char> struct parse_specs_result {
+  formatter<T, Char> fmt;
+  size_t end;
+  int next_arg_id;
+};
+
+template <typename T, typename Char>
+constexpr parse_specs_result<T, Char> parse_specs(basic_string_view<Char> str,
+                                                  size_t pos, int arg_id) {
+  str.remove_prefix(pos);
+  auto ctx = basic_format_parse_context<Char>(str, {}, arg_id + 1);
+  auto f = formatter<T, Char>();
+  auto end = f.parse(ctx);
+  return {f, pos + (end - str.data()) + 1, ctx.next_arg_id()};
+}
+
 // Compiles a non-empty format string and returns the compiled representation
 // or unknown_format() on unrecognized input.
 template <typename Args, size_t POS, int ID, typename S>
@@ -463,12 +531,13 @@ constexpr auto compile_format_string(S format_str) {
       return parse_tail<Args, POS + 2, ID>(make_text(str, POS, 1), format_str);
     } else if constexpr (str[POS + 1] == '}') {
       using type = get_type<ID, Args>;
-      if constexpr (std::is_same<type, int>::value) {
-        return parse_tail<Args, POS + 2, ID + 1>(field<char_type, type, ID>(),
-                                                 format_str);
-      } else {
-        return unknown_format();
-      }
+      return parse_tail<Args, POS + 2, ID + 1>(field<char_type, type, ID>(),
+                                               format_str);
+    } else if constexpr (str[POS + 1] == ':') {
+      using type = get_type<ID, Args>;
+      constexpr auto result = parse_specs<type>(str, POS + 2, ID);
+      return parse_tail<Args, result.end, result.next_arg_id>(
+          spec_field<char_type, type, ID>{result.fmt}, format_str);
     } else {
       return unknown_format();
     }
@@ -478,106 +547,152 @@ constexpr auto compile_format_string(S format_str) {
     return parse_tail<Args, POS + 2, ID>(make_text(str, POS, 1), format_str);
   } else {
     constexpr auto end = parse_text(str, POS + 1);
-    return parse_tail<Args, end, ID>(make_text(str, POS, end - POS),
-                                     format_str);
+    if constexpr (end - POS > 1) {
+      return parse_tail<Args, end, ID>(make_text(str, POS, end - POS),
+                                       format_str);
+    } else {
+      return parse_tail<Args, end, ID>(code_unit<char_type>{str[POS]},
+                                       format_str);
+    }
   }
 }
-#endif  // __cpp_if_constexpr
-}  // namespace internal
 
-#if FMT_USE_CONSTEXPR
-#  ifdef __cpp_if_constexpr
 template <typename... Args, typename S,
-          FMT_ENABLE_IF(is_compile_string<S>::value)>
+          FMT_ENABLE_IF(is_compile_string<S>::value ||
+                        detail::is_compiled_string<S>::value)>
 constexpr auto compile(S format_str) {
   constexpr basic_string_view<typename S::char_type> str = format_str;
   if constexpr (str.size() == 0) {
-    return internal::make_text(str, 0, 0);
+    return detail::make_text(str, 0, 0);
   } else {
     constexpr auto result =
-        internal::compile_format_string<internal::type_list<Args...>, 0, 0>(
+        detail::compile_format_string<detail::type_list<Args...>, 0, 0>(
             format_str);
     if constexpr (std::is_same<remove_cvref_t<decltype(result)>,
-                               internal::unknown_format>()) {
-      return internal::compiled_format<S, Args...>(to_string_view(format_str));
+                               detail::unknown_format>()) {
+      return detail::compiled_format<S, Args...>(to_string_view(format_str));
     } else {
       return result;
     }
   }
 }
+#else
+template <typename... Args, typename S,
+          FMT_ENABLE_IF(is_compile_string<S>::value)>
+constexpr auto compile(S format_str) -> detail::compiled_format<S, Args...> {
+  return detail::compiled_format<S, Args...>(to_string_view(format_str));
+}
+#endif  // __cpp_if_constexpr
+
+// Compiles the format string which must be a string literal.
+template <typename... Args, typename Char, size_t N>
+auto compile(const Char (&format_str)[N])
+    -> detail::compiled_format<const Char*, Args...> {
+  return detail::compiled_format<const Char*, Args...>(
+      basic_string_view<Char>(format_str, N - 1));
+}
+}  // namespace detail
+
+// DEPRECATED! use FMT_COMPILE instead.
+template <typename... Args>
+FMT_DEPRECATED auto compile(const Args&... args)
+    -> decltype(detail::compile(args...)) {
+  return detail::compile(args...);
+}
+
+#if FMT_USE_CONSTEXPR
+#  ifdef __cpp_if_constexpr
 
 template <typename CompiledFormat, typename... Args,
           typename Char = typename CompiledFormat::char_type,
-          FMT_ENABLE_IF(!std::is_base_of<internal::basic_compiled_format,
-                                         CompiledFormat>::value)>
-std::basic_string<Char> format(const CompiledFormat& cf, const Args&... args) {
+          FMT_ENABLE_IF(detail::is_compiled_format<CompiledFormat>::value)>
+FMT_INLINE std::basic_string<Char> format(const CompiledFormat& cf,
+                                          const Args&... args) {
   basic_memory_buffer<Char> buffer;
-  cf.format(std::back_inserter(buffer), args...);
+  cf.format(detail::buffer_appender<Char>(buffer), args...);
   return to_string(buffer);
 }
 
 template <typename OutputIt, typename CompiledFormat, typename... Args,
-          FMT_ENABLE_IF(!std::is_base_of<internal::basic_compiled_format,
-                                         CompiledFormat>::value)>
+          FMT_ENABLE_IF(detail::is_compiled_format<CompiledFormat>::value)>
 OutputIt format_to(OutputIt out, const CompiledFormat& cf,
                    const Args&... args) {
   return cf.format(out, args...);
 }
-#  else
-template <typename... Args, typename S,
-          FMT_ENABLE_IF(is_compile_string<S>::value)>
-constexpr auto compile(S format_str) -> internal::compiled_format<S, Args...> {
-  return internal::compiled_format<S, Args...>(to_string_view(format_str));
-}
 #  endif  // __cpp_if_constexpr
 #endif    // FMT_USE_CONSTEXPR
 
-// Compiles the format string which must be a string literal.
-template <typename... Args, typename Char, size_t N>
-auto compile(const Char (&format_str)[N])
-    -> internal::compiled_format<const Char*, Args...> {
-  return internal::compiled_format<const Char*, Args...>(
-      basic_string_view<Char>(format_str, N - 1));
-}
-
 template <typename CompiledFormat, typename... Args,
           typename Char = typename CompiledFormat::char_type,
-          FMT_ENABLE_IF(std::is_base_of<internal::basic_compiled_format,
+          FMT_ENABLE_IF(std::is_base_of<detail::basic_compiled_format,
                                         CompiledFormat>::value)>
 std::basic_string<Char> format(const CompiledFormat& cf, const Args&... args) {
   basic_memory_buffer<Char> buffer;
-  using range = buffer_range<Char>;
   using context = buffer_context<Char>;
-  internal::cf::vformat_to<context>(range(buffer), cf,
-                                    {make_format_args<context>(args...)});
+  detail::cf::vformat_to<context>(detail::buffer_appender<Char>(buffer), cf,
+                                  make_format_args<context>(args...));
   return to_string(buffer);
 }
 
+template <typename S, typename... Args,
+          FMT_ENABLE_IF(detail::is_compiled_string<S>::value)>
+FMT_INLINE std::basic_string<typename S::char_type> format(const S&,
+                                                           Args&&... args) {
+#ifdef __cpp_if_constexpr
+  if constexpr (std::is_same<typename S::char_type, char>::value) {
+    constexpr basic_string_view<typename S::char_type> str = S();
+    if (str.size() == 2 && str[0] == '{' && str[1] == '}')
+      return fmt::to_string(detail::first(args...));
+  }
+#endif
+  constexpr auto compiled = detail::compile<Args...>(S());
+  return format(compiled, std::forward<Args>(args)...);
+}
+
 template <typename OutputIt, typename CompiledFormat, typename... Args,
-          FMT_ENABLE_IF(std::is_base_of<internal::basic_compiled_format,
+          FMT_ENABLE_IF(std::is_base_of<detail::basic_compiled_format,
                                         CompiledFormat>::value)>
 OutputIt format_to(OutputIt out, const CompiledFormat& cf,
                    const Args&... args) {
   using char_type = typename CompiledFormat::char_type;
-  using range = internal::output_range<OutputIt, char_type>;
   using context = format_context_t<OutputIt, char_type>;
-  return internal::cf::vformat_to<context>(
-      range(out), cf, {make_format_args<context>(args...)});
+  return detail::cf::vformat_to<context>(out, cf,
+                                         make_format_args<context>(args...));
+}
+
+template <typename OutputIt, typename S, typename... Args,
+          FMT_ENABLE_IF(detail::is_compiled_string<S>::value)>
+OutputIt format_to(OutputIt out, const S&, const Args&... args) {
+  constexpr auto compiled = detail::compile<Args...>(S());
+  return format_to(out, compiled, args...);
 }
 
 template <typename OutputIt, typename CompiledFormat, typename... Args,
-          FMT_ENABLE_IF(internal::is_output_iterator<OutputIt>::value)>
+          FMT_ENABLE_IF(detail::is_output_iterator<
+                        OutputIt, typename CompiledFormat::char_type>::value&&
+                            std::is_base_of<detail::basic_compiled_format,
+                                            CompiledFormat>::value)>
 format_to_n_result<OutputIt> format_to_n(OutputIt out, size_t n,
                                          const CompiledFormat& cf,
                                          const Args&... args) {
   auto it =
-      format_to(internal::truncating_iterator<OutputIt>(out, n), cf, args...);
+      format_to(detail::truncating_iterator<OutputIt>(out, n), cf, args...);
+  return {it.base(), it.count()};
+}
+
+template <typename OutputIt, typename S, typename... Args,
+          FMT_ENABLE_IF(detail::is_compiled_string<S>::value)>
+format_to_n_result<OutputIt> format_to_n(OutputIt out, size_t n, const S&,
+                                         const Args&... args) {
+  constexpr auto compiled = detail::compile<Args...>(S());
+  auto it = format_to(detail::truncating_iterator<OutputIt>(out, n), compiled,
+                      args...);
   return {it.base(), it.count()};
 }
 
 template <typename CompiledFormat, typename... Args>
-std::size_t formatted_size(const CompiledFormat& cf, const Args&... args) {
-  return format_to(internal::counting_iterator(), cf, args...).count();
+size_t formatted_size(const CompiledFormat& cf, const Args&... args) {
+  return format_to(detail::counting_iterator(), cf, args...).count();
 }
 
 FMT_END_NAMESPACE
diff --git a/Externals/fmt/include/fmt/core.h b/Externals/fmt/include/fmt/core.h
index 9fd8df287851..2903be5a0715 100755
--- a/Externals/fmt/include/fmt/core.h
+++ b/Externals/fmt/include/fmt/core.h
@@ -10,30 +10,20 @@
 
 #include <cstdio>  // std::FILE
 #include <cstring>
+#include <functional>
 #include <iterator>
+#include <memory>
 #include <string>
 #include <type_traits>
+#include <vector>
 
 // The fmt library version in the form major * 10000 + minor * 100 + patch.
-#define FMT_VERSION 60102
+#define FMT_VERSION 70100
 
-#ifdef __has_feature
-#  define FMT_HAS_FEATURE(x) __has_feature(x)
-#else
-#  define FMT_HAS_FEATURE(x) 0
-#endif
-
-#if defined(__has_include) && !defined(__INTELLISENSE__) && \
-    !(defined(__INTEL_COMPILER) && __INTEL_COMPILER < 1600)
-#  define FMT_HAS_INCLUDE(x) __has_include(x)
+#ifdef __clang__
+#  define FMT_CLANG_VERSION (__clang_major__ * 100 + __clang_minor__)
 #else
-#  define FMT_HAS_INCLUDE(x) 0
-#endif
-
-#ifdef __has_cpp_attribute
-#  define FMT_HAS_CPP_ATTRIBUTE(x) __has_cpp_attribute(x)
-#else
-#  define FMT_HAS_CPP_ATTRIBUTE(x) 0
+#  define FMT_CLANG_VERSION 0
 #endif
 
 #if defined(__GNUC__) && !defined(__clang__)
@@ -42,6 +32,12 @@
 #  define FMT_GCC_VERSION 0
 #endif
 
+#if defined(__INTEL_COMPILER)
+#  define FMT_ICC_VERSION __INTEL_COMPILER
+#else
+#  define FMT_ICC_VERSION 0
+#endif
+
 #if __cplusplus >= 201103L || defined(__GXX_EXPERIMENTAL_CXX0X__)
 #  define FMT_HAS_GXX_CXX11 FMT_GCC_VERSION
 #else
@@ -56,17 +52,44 @@
 
 #ifdef _MSC_VER
 #  define FMT_MSC_VER _MSC_VER
+#  define FMT_SUPPRESS_MSC_WARNING(n) __pragma(warning(suppress : n))
 #else
 #  define FMT_MSC_VER 0
+#  define FMT_SUPPRESS_MSC_WARNING(n)
 #endif
 
+#ifdef __has_feature
+#  define FMT_HAS_FEATURE(x) __has_feature(x)
+#else
+#  define FMT_HAS_FEATURE(x) 0
+#endif
+
+#if defined(__has_include) && !defined(__INTELLISENSE__) && \
+    (!FMT_ICC_VERSION || FMT_ICC_VERSION >= 1600)
+#  define FMT_HAS_INCLUDE(x) __has_include(x)
+#else
+#  define FMT_HAS_INCLUDE(x) 0
+#endif
+
+#ifdef __has_cpp_attribute
+#  define FMT_HAS_CPP_ATTRIBUTE(x) __has_cpp_attribute(x)
+#else
+#  define FMT_HAS_CPP_ATTRIBUTE(x) 0
+#endif
+
+#define FMT_HAS_CPP14_ATTRIBUTE(attribute) \
+  (__cplusplus >= 201402L && FMT_HAS_CPP_ATTRIBUTE(attribute))
+
+#define FMT_HAS_CPP17_ATTRIBUTE(attribute) \
+  (__cplusplus >= 201703L && FMT_HAS_CPP_ATTRIBUTE(attribute))
+
 // Check if relaxed C++14 constexpr is supported.
 // GCC doesn't allow throw in constexpr until version 6 (bug 67371).
 #ifndef FMT_USE_CONSTEXPR
 #  define FMT_USE_CONSTEXPR                                           \
     (FMT_HAS_FEATURE(cxx_relaxed_constexpr) || FMT_MSC_VER >= 1910 || \
      (FMT_GCC_VERSION >= 600 && __cplusplus >= 201402L)) &&           \
-        !FMT_NVCC
+        !FMT_NVCC && !FMT_ICC_VERSION
 #endif
 #if FMT_USE_CONSTEXPR
 #  define FMT_CONSTEXPR constexpr
@@ -77,7 +100,7 @@
 #endif
 
 #ifndef FMT_OVERRIDE
-#  if FMT_HAS_FEATURE(cxx_override) || \
+#  if FMT_HAS_FEATURE(cxx_override_control) || \
       (FMT_GCC_VERSION >= 408 && FMT_HAS_GXX_CXX11) || FMT_MSC_VER >= 1900
 #    define FMT_OVERRIDE override
 #  else
@@ -117,19 +140,20 @@
 #  endif
 #endif
 
-// [[noreturn]] is disabled on MSVC because of bogus unreachable code warnings.
-#if FMT_EXCEPTIONS && FMT_HAS_CPP_ATTRIBUTE(noreturn) && !FMT_MSC_VER
+// [[noreturn]] is disabled on MSVC and NVCC because of bogus unreachable code
+// warnings.
+#if FMT_EXCEPTIONS && FMT_HAS_CPP_ATTRIBUTE(noreturn) && !FMT_MSC_VER && \
+    !FMT_NVCC
 #  define FMT_NORETURN [[noreturn]]
 #else
 #  define FMT_NORETURN
 #endif
 
 #ifndef FMT_DEPRECATED
-#  if (FMT_HAS_CPP_ATTRIBUTE(deprecated) && __cplusplus >= 201402L) || \
-      FMT_MSC_VER >= 1900
+#  if FMT_HAS_CPP14_ATTRIBUTE(deprecated) || FMT_MSC_VER >= 1900
 #    define FMT_DEPRECATED [[deprecated]]
 #  else
-#    if defined(__GNUC__) || defined(__clang__)
+#    if (defined(__GNUC__) && !defined(__LCC__)) || defined(__clang__)
 #      define FMT_DEPRECATED __attribute__((deprecated))
 #    elif FMT_MSC_VER
 #      define FMT_DEPRECATED __declspec(deprecated)
@@ -139,16 +163,32 @@
 #  endif
 #endif
 
-// Workaround broken [[deprecated]] in the Intel compiler and NVCC.
-#if defined(__INTEL_COMPILER) || FMT_NVCC
+// Workaround broken [[deprecated]] in the Intel, PGI and NVCC compilers.
+#if FMT_ICC_VERSION || defined(__PGI) || FMT_NVCC
 #  define FMT_DEPRECATED_ALIAS
 #else
 #  define FMT_DEPRECATED_ALIAS FMT_DEPRECATED
 #endif
 
-#ifndef FMT_BEGIN_NAMESPACE
+#ifndef FMT_INLINE
+#  if FMT_GCC_VERSION || FMT_CLANG_VERSION
+#    define FMT_INLINE inline __attribute__((always_inline))
+#  else
+#    define FMT_INLINE inline
+#  endif
+#endif
+
+#ifndef FMT_USE_INLINE_NAMESPACES
 #  if FMT_HAS_FEATURE(cxx_inline_namespaces) || FMT_GCC_VERSION >= 404 || \
-      FMT_MSC_VER >= 1900
+      (FMT_MSC_VER >= 1900 && !_MANAGED)
+#    define FMT_USE_INLINE_NAMESPACES 1
+#  else
+#    define FMT_USE_INLINE_NAMESPACES 0
+#  endif
+#endif
+
+#ifndef FMT_BEGIN_NAMESPACE
+#  if FMT_USE_INLINE_NAMESPACES
 #    define FMT_INLINE_NAMESPACE inline namespace
 #    define FMT_END_NAMESPACE \
       }                       \
@@ -157,21 +197,26 @@
 #    define FMT_INLINE_NAMESPACE namespace
 #    define FMT_END_NAMESPACE \
       }                       \
-      using namespace v6;     \
+      using namespace v7;     \
       }
 #  endif
 #  define FMT_BEGIN_NAMESPACE \
     namespace fmt {           \
-    FMT_INLINE_NAMESPACE v6 {
+    FMT_INLINE_NAMESPACE v7 {
 #endif
 
 #if !defined(FMT_HEADER_ONLY) && defined(_WIN32)
+#  define FMT_CLASS_API FMT_SUPPRESS_MSC_WARNING(4275)
 #  ifdef FMT_EXPORT
 #    define FMT_API __declspec(dllexport)
+#    define FMT_EXTERN_TEMPLATE_API FMT_API
+#    define FMT_EXPORTED
 #  elif defined(FMT_SHARED)
 #    define FMT_API __declspec(dllimport)
 #    define FMT_EXTERN_TEMPLATE_API FMT_API
 #  endif
+#else
+#  define FMT_CLASS_API
 #endif
 #ifndef FMT_API
 #  define FMT_API
@@ -179,6 +224,9 @@
 #ifndef FMT_EXTERN_TEMPLATE_API
 #  define FMT_EXTERN_TEMPLATE_API
 #endif
+#ifndef FMT_INSTANTIATION_DEF_API
+#  define FMT_INSTANTIATION_DEF_API FMT_API
+#endif
 
 #ifndef FMT_HEADER_ONLY
 #  define FMT_EXTERN extern
@@ -197,9 +245,16 @@
 #  define FMT_USE_EXPERIMENTAL_STRING_VIEW
 #endif
 
+#ifndef FMT_UNICODE
+#  define FMT_UNICODE !FMT_MSC_VER
+#endif
+#if FMT_UNICODE && FMT_MSC_VER
+#  pragma execution_character_set("utf-8")
+#endif
+
 FMT_BEGIN_NAMESPACE
 
-// Implementations of enable_if_t and other types for pre-C++14 systems.
+// Implementations of enable_if_t and other metafunctions for older systems.
 template <bool B, class T = void>
 using enable_if_t = typename std::enable_if<B, T>::type;
 template <bool B, class T, class F>
@@ -211,6 +266,8 @@ template <typename T>
 using remove_const_t = typename std::remove_const<T>::type;
 template <typename T>
 using remove_cvref_t = typename std::remove_cv<remove_reference_t<T>>::type;
+template <typename T> struct type_identity { using type = T; };
+template <typename T> using type_identity_t = typename type_identity<T>::type;
 
 struct monostate {};
 
@@ -219,21 +276,23 @@ struct monostate {};
 // to workaround a bug in MSVC 2019 (see #1140 and #1186).
 #define FMT_ENABLE_IF(...) enable_if_t<(__VA_ARGS__), int> = 0
 
-namespace internal {
+namespace detail {
 
-// A workaround for gcc 4.8 to make void_t work in a SFINAE context.
-template <typename... Ts> struct void_t_impl { using type = void; };
+// A helper function to suppress "conditional expression is constant" warnings.
+template <typename T> constexpr T const_check(T value) { return value; }
 
-FMT_API void assert_fail(const char* file, int line, const char* message);
+FMT_NORETURN FMT_API void assert_fail(const char* file, int line,
+                                      const char* message);
 
 #ifndef FMT_ASSERT
 #  ifdef NDEBUG
-#    define FMT_ASSERT(condition, message)
+// FMT_ASSERT is not empty to avoid -Werror=empty-body.
+#    define FMT_ASSERT(condition, message) ((void)0)
 #  else
-#    define FMT_ASSERT(condition, message) \
-      ((condition)                         \
-           ? void()                        \
-           : fmt::internal::assert_fail(__FILE__, __LINE__, (message)))
+#    define FMT_ASSERT(condition, message)                                    \
+      ((condition) /* void() fails with -Winvalid-constexpr on clang 4.0.1 */ \
+           ? (void)0                                                          \
+           : ::fmt::detail::assert_fail(__FILE__, __LINE__, (message)))
 #  endif
 #endif
 
@@ -248,7 +307,8 @@ template <typename T> struct std_string_view {};
 
 #ifdef FMT_USE_INT128
 // Do nothing.
-#elif defined(__SIZEOF_INT128__)
+#elif defined(__SIZEOF_INT128__) && !FMT_NVCC && \
+    !(FMT_CLANG_VERSION && FMT_MSC_VER)
 #  define FMT_USE_INT128 1
 using int128_t = __int128_t;
 using uint128_t = __uint128_t;
@@ -266,10 +326,24 @@ FMT_CONSTEXPR typename std::make_unsigned<Int>::type to_unsigned(Int value) {
   FMT_ASSERT(value >= 0, "negative value");
   return static_cast<typename std::make_unsigned<Int>::type>(value);
 }
-}  // namespace internal
 
-template <typename... Ts>
-using void_t = typename internal::void_t_impl<Ts...>::type;
+FMT_SUPPRESS_MSC_WARNING(4566) constexpr unsigned char micro[] = "\u00B5";
+
+template <typename Char> constexpr bool is_unicode() {
+  return FMT_UNICODE || sizeof(Char) != 1 ||
+         (sizeof(micro) == 3 && micro[0] == 0xC2 && micro[1] == 0xB5);
+}
+
+#ifdef __cpp_char8_t
+using char8_type = char8_t;
+#else
+enum char8_type : unsigned char {};
+#endif
+}  // namespace detail
+
+#ifdef FMT_USE_INTERNAL
+namespace internal = detail;  // DEPRECATED
+#endif
 
 /**
   An implementation of ``std::basic_string_view`` for pre-C++17. It provides a
@@ -284,13 +358,13 @@ template <typename Char> class basic_string_view {
   size_t size_;
 
  public:
-  using char_type = Char;
+  using value_type = Char;
   using iterator = const Char*;
 
-  FMT_CONSTEXPR basic_string_view() FMT_NOEXCEPT : data_(nullptr), size_(0) {}
+  constexpr basic_string_view() FMT_NOEXCEPT : data_(nullptr), size_(0) {}
 
   /** Constructs a string reference object from a C string and a size. */
-  FMT_CONSTEXPR basic_string_view(const Char* s, size_t count) FMT_NOEXCEPT
+  constexpr basic_string_view(const Char* s, size_t count) FMT_NOEXCEPT
       : data_(s),
         size_(count) {}
 
@@ -300,6 +374,9 @@ template <typename Char> class basic_string_view {
     the size with ``std::char_traits<Char>::length``.
     \endrst
    */
+#if __cplusplus >= 201703L  // C++17's char_traits::length() is constexpr.
+  FMT_CONSTEXPR
+#endif
   basic_string_view(const Char* s)
       : data_(s), size_(std::char_traits<Char>::length(s)) {}
 
@@ -310,22 +387,21 @@ template <typename Char> class basic_string_view {
       : data_(s.data()),
         size_(s.size()) {}
 
-  template <
-      typename S,
-      FMT_ENABLE_IF(std::is_same<S, internal::std_string_view<Char>>::value)>
+  template <typename S, FMT_ENABLE_IF(std::is_same<
+                                      S, detail::std_string_view<Char>>::value)>
   FMT_CONSTEXPR basic_string_view(S s) FMT_NOEXCEPT : data_(s.data()),
                                                       size_(s.size()) {}
 
   /** Returns a pointer to the string data. */
-  FMT_CONSTEXPR const Char* data() const { return data_; }
+  constexpr const Char* data() const { return data_; }
 
   /** Returns the string size. */
-  FMT_CONSTEXPR size_t size() const { return size_; }
+  constexpr size_t size() const { return size_; }
 
-  FMT_CONSTEXPR iterator begin() const { return data_; }
-  FMT_CONSTEXPR iterator end() const { return data_ + size_; }
+  constexpr iterator begin() const { return data_; }
+  constexpr iterator end() const { return data_ + size_; }
 
-  FMT_CONSTEXPR const Char& operator[](size_t pos) const { return data_[pos]; }
+  constexpr const Char& operator[](size_t pos) const { return data_[pos]; }
 
   FMT_CONSTEXPR void remove_prefix(size_t n) {
     data_ += n;
@@ -364,16 +440,11 @@ template <typename Char> class basic_string_view {
 using string_view = basic_string_view<char>;
 using wstring_view = basic_string_view<wchar_t>;
 
-#ifndef __cpp_char8_t
-// A UTF-8 code unit type.
-enum char8_t : unsigned char {};
-#endif
-
 /** Specifies if ``T`` is a character type. Can be specialized by users. */
 template <typename T> struct is_char : std::false_type {};
 template <> struct is_char<char> : std::true_type {};
 template <> struct is_char<wchar_t> : std::true_type {};
-template <> struct is_char<char8_t> : std::true_type {};
+template <> struct is_char<detail::char8_type> : std::true_type {};
 template <> struct is_char<char16_t> : std::true_type {};
 template <> struct is_char<char32_t> : std::true_type {};
 
@@ -410,14 +481,13 @@ inline basic_string_view<Char> to_string_view(basic_string_view<Char> s) {
 }
 
 template <typename Char,
-          FMT_ENABLE_IF(!std::is_empty<internal::std_string_view<Char>>::value)>
-inline basic_string_view<Char> to_string_view(
-    internal::std_string_view<Char> s) {
+          FMT_ENABLE_IF(!std::is_empty<detail::std_string_view<Char>>::value)>
+inline basic_string_view<Char> to_string_view(detail::std_string_view<Char> s) {
   return s;
 }
 
 // A base class for compile-time strings. It is defined in the fmt namespace to
-// make formatting functions visible via ADL, e.g. format(fmt("{}"), 42).
+// make formatting functions visible via ADL, e.g. format(FMT_STRING("{}"), 42).
 struct compile_string {};
 
 template <typename S>
@@ -428,9 +498,9 @@ constexpr basic_string_view<typename S::char_type> to_string_view(const S& s) {
   return s;
 }
 
-namespace internal {
+namespace detail {
 void to_string_view(...);
-using fmt::v6::to_string_view;
+using fmt::v7::to_string_view;
 
 // Specifies whether S is a string type convertible to fmt::basic_string_view.
 // It should be a constexpr function but MSVC 2017 fails to compile it in
@@ -442,20 +512,32 @@ struct is_string : std::is_class<decltype(to_string_view(std::declval<S>()))> {
 template <typename S, typename = void> struct char_t_impl {};
 template <typename S> struct char_t_impl<S, enable_if_t<is_string<S>::value>> {
   using result = decltype(to_string_view(std::declval<S>()));
-  using type = typename result::char_type;
+  using type = typename result::value_type;
 };
 
+// Reports a compile-time error if S is not a valid format string.
+template <typename..., typename S, FMT_ENABLE_IF(!is_compile_string<S>::value)>
+FMT_INLINE void check_format_string(const S&) {
+#ifdef FMT_ENFORCE_COMPILE_STRING
+  static_assert(is_compile_string<S>::value,
+                "FMT_ENFORCE_COMPILE_STRING requires all format strings to use "
+                "FMT_STRING.");
+#endif
+}
+template <typename..., typename S, FMT_ENABLE_IF(is_compile_string<S>::value)>
+void check_format_string(S);
+
 struct error_handler {
-  FMT_CONSTEXPR error_handler() = default;
-  FMT_CONSTEXPR error_handler(const error_handler&) = default;
+  constexpr error_handler() = default;
+  constexpr error_handler(const error_handler&) = default;
 
   // This function is intentionally not constexpr to give a compile-time error.
   FMT_NORETURN FMT_API void on_error(const char* message);
 };
-}  // namespace internal
+}  // namespace detail
 
 /** String's character type. */
-template <typename S> using char_t = typename internal::char_t_impl<S>::type;
+template <typename S> using char_t = typename detail::char_t_impl<S>::type;
 
 /**
   \rst
@@ -473,7 +555,7 @@ template <typename S> using char_t = typename internal::char_t_impl<S>::type;
   +-----------------------+-------------------------------------+
   \endrst
  */
-template <typename Char, typename ErrorHandler = internal::error_handler>
+template <typename Char, typename ErrorHandler = detail::error_handler>
 class basic_format_parse_context : private ErrorHandler {
  private:
   basic_string_view<Char> format_str_;
@@ -483,26 +565,25 @@ class basic_format_parse_context : private ErrorHandler {
   using char_type = Char;
   using iterator = typename basic_string_view<Char>::iterator;
 
-  explicit FMT_CONSTEXPR basic_format_parse_context(
-      basic_string_view<Char> format_str, ErrorHandler eh = ErrorHandler())
-      : ErrorHandler(eh), format_str_(format_str), next_arg_id_(0) {}
+  explicit constexpr basic_format_parse_context(
+      basic_string_view<Char> format_str, ErrorHandler eh = {},
+      int next_arg_id = 0)
+      : ErrorHandler(eh), format_str_(format_str), next_arg_id_(next_arg_id) {}
 
   /**
     Returns an iterator to the beginning of the format string range being
     parsed.
    */
-  FMT_CONSTEXPR iterator begin() const FMT_NOEXCEPT {
-    return format_str_.begin();
-  }
+  constexpr iterator begin() const FMT_NOEXCEPT { return format_str_.begin(); }
 
   /**
     Returns an iterator past the end of the format string range being parsed.
    */
-  FMT_CONSTEXPR iterator end() const FMT_NOEXCEPT { return format_str_.end(); }
+  constexpr iterator end() const FMT_NOEXCEPT { return format_str_.end(); }
 
   /** Advances the begin iterator to ``it``. */
   FMT_CONSTEXPR void advance_to(iterator it) {
-    format_str_.remove_prefix(internal::to_unsigned(it - begin()));
+    format_str_.remove_prefix(detail::to_unsigned(it - begin()));
   }
 
   /**
@@ -510,6 +591,8 @@ class basic_format_parse_context : private ErrorHandler {
     the next argument index and switches to the automatic indexing.
    */
   FMT_CONSTEXPR int next_arg_id() {
+    // Don't check if the argument id is valid to avoid overhead and because it
+    // will be checked during formatting anyway.
     if (next_arg_id_ >= 0) return next_arg_id_++;
     on_error("cannot switch from manual to automatic argument indexing");
     return 0;
@@ -532,20 +615,15 @@ class basic_format_parse_context : private ErrorHandler {
     ErrorHandler::on_error(message);
   }
 
-  FMT_CONSTEXPR ErrorHandler error_handler() const { return *this; }
+  constexpr ErrorHandler error_handler() const { return *this; }
 };
 
 using format_parse_context = basic_format_parse_context<char>;
 using wformat_parse_context = basic_format_parse_context<wchar_t>;
 
-template <typename Char, typename ErrorHandler = internal::error_handler>
-using basic_parse_context FMT_DEPRECATED_ALIAS =
-    basic_format_parse_context<Char, ErrorHandler>;
-using parse_context FMT_DEPRECATED_ALIAS = basic_format_parse_context<char>;
-using wparse_context FMT_DEPRECATED_ALIAS = basic_format_parse_context<wchar_t>;
-
 template <typename Context> class basic_format_arg;
 template <typename Context> class basic_format_args;
+template <typename Context> class dynamic_format_arg_store;
 
 // A formatter for objects of type T.
 template <typename T, typename Char = char, typename Enable = void>
@@ -554,43 +632,62 @@ struct formatter {
   formatter() = delete;
 };
 
-template <typename T, typename Char, typename Enable = void>
-struct FMT_DEPRECATED convert_to_int
-    : bool_constant<!std::is_arithmetic<T>::value &&
-                    std::is_convertible<T, int>::value> {};
-
 // Specifies if T has an enabled formatter specialization. A type can be
 // formattable even if it doesn't have a formatter e.g. via a conversion.
 template <typename T, typename Context>
 using has_formatter =
     std::is_constructible<typename Context::template formatter_type<T>>;
 
-namespace internal {
+// Checks whether T is a container with contiguous storage.
+template <typename T> struct is_contiguous : std::false_type {};
+template <typename Char>
+struct is_contiguous<std::basic_string<Char>> : std::true_type {};
+
+namespace detail {
+
+// Extracts a reference to the container from back_insert_iterator.
+template <typename Container>
+inline Container& get_container(std::back_insert_iterator<Container> it) {
+  using bi_iterator = std::back_insert_iterator<Container>;
+  struct accessor : bi_iterator {
+    accessor(bi_iterator iter) : bi_iterator(iter) {}
+    using bi_iterator::container;
+  };
+  return *accessor(it).container;
+}
 
-/** A contiguous memory buffer with an optional growing ability. */
+/**
+  \rst
+  A contiguous memory buffer with an optional growing ability. It is an internal
+  class and shouldn't be used directly, only via `~fmt::basic_memory_buffer`.
+  \endrst
+ */
 template <typename T> class buffer {
  private:
   T* ptr_;
-  std::size_t size_;
-  std::size_t capacity_;
+  size_t size_;
+  size_t capacity_;
 
  protected:
   // Don't initialize ptr_ since it is not accessed to save a few cycles.
-  buffer(std::size_t sz) FMT_NOEXCEPT : size_(sz), capacity_(sz) {}
+  FMT_SUPPRESS_MSC_WARNING(26495)
+  buffer(size_t sz) FMT_NOEXCEPT : size_(sz), capacity_(sz) {}
 
-  buffer(T* p = nullptr, std::size_t sz = 0, std::size_t cap = 0) FMT_NOEXCEPT
+  buffer(T* p = nullptr, size_t sz = 0, size_t cap = 0) FMT_NOEXCEPT
       : ptr_(p),
         size_(sz),
         capacity_(cap) {}
 
+  ~buffer() = default;
+
   /** Sets the buffer data and capacity. */
-  void set(T* buf_data, std::size_t buf_capacity) FMT_NOEXCEPT {
+  void set(T* buf_data, size_t buf_capacity) FMT_NOEXCEPT {
     ptr_ = buf_data;
     capacity_ = buf_capacity;
   }
 
   /** Increases the buffer capacity to hold at least *capacity* elements. */
-  virtual void grow(std::size_t capacity) = 0;
+  virtual void grow(size_t capacity) = 0;
 
  public:
   using value_type = T;
@@ -598,16 +695,18 @@ template <typename T> class buffer {
 
   buffer(const buffer&) = delete;
   void operator=(const buffer&) = delete;
-  virtual ~buffer() = default;
 
   T* begin() FMT_NOEXCEPT { return ptr_; }
   T* end() FMT_NOEXCEPT { return ptr_ + size_; }
 
+  const T* begin() const FMT_NOEXCEPT { return ptr_; }
+  const T* end() const FMT_NOEXCEPT { return ptr_ + size_; }
+
   /** Returns the size of this buffer. */
-  std::size_t size() const FMT_NOEXCEPT { return size_; }
+  size_t size() const FMT_NOEXCEPT { return size_; }
 
   /** Returns the capacity of this buffer. */
-  std::size_t capacity() const FMT_NOEXCEPT { return capacity_; }
+  size_t capacity() const FMT_NOEXCEPT { return capacity_; }
 
   /** Returns a pointer to the buffer data. */
   T* data() FMT_NOEXCEPT { return ptr_; }
@@ -615,60 +714,182 @@ template <typename T> class buffer {
   /** Returns a pointer to the buffer data. */
   const T* data() const FMT_NOEXCEPT { return ptr_; }
 
-  /**
-    Resizes the buffer. If T is a POD type new elements may not be initialized.
-   */
-  void resize(std::size_t new_size) {
-    reserve(new_size);
-    size_ = new_size;
-  }
-
   /** Clears this buffer. */
   void clear() { size_ = 0; }
 
-  /** Reserves space to store at least *capacity* elements. */
-  void reserve(std::size_t new_capacity) {
+  // Tries resizing the buffer to contain *count* elements. If T is a POD type
+  // the new elements may not be initialized.
+  void try_resize(size_t count) {
+    try_reserve(count);
+    size_ = count <= capacity_ ? count : capacity_;
+  }
+
+  // Tries increasing the buffer capacity to *new_capacity*. It can increase the
+  // capacity by a smaller amount than requested but guarantees there is space
+  // for at least one additional element either by increasing the capacity or by
+  // flushing the buffer if it is full.
+  void try_reserve(size_t new_capacity) {
     if (new_capacity > capacity_) grow(new_capacity);
   }
 
   void push_back(const T& value) {
-    reserve(size_ + 1);
+    try_reserve(size_ + 1);
     ptr_[size_++] = value;
   }
 
   /** Appends data to the end of the buffer. */
   template <typename U> void append(const U* begin, const U* end);
 
-  T& operator[](std::size_t index) { return ptr_[index]; }
-  const T& operator[](std::size_t index) const { return ptr_[index]; }
+  template <typename I> T& operator[](I index) { return ptr_[index]; }
+  template <typename I> const T& operator[](I index) const {
+    return ptr_[index];
+  }
+};
+
+struct buffer_traits {
+  explicit buffer_traits(size_t) {}
+  size_t count() const { return 0; }
+  size_t limit(size_t size) { return size; }
+};
+
+class fixed_buffer_traits {
+ private:
+  size_t count_ = 0;
+  size_t limit_;
+
+ public:
+  explicit fixed_buffer_traits(size_t limit) : limit_(limit) {}
+  size_t count() const { return count_; }
+  size_t limit(size_t size) {
+    size_t n = limit_ - count_;
+    count_ += size;
+    return size < n ? size : n;
+  }
 };
 
-// A container-backed buffer.
+// A buffer that writes to an output iterator when flushed.
+template <typename OutputIt, typename T, typename Traits = buffer_traits>
+class iterator_buffer final : public Traits, public buffer<T> {
+ private:
+  OutputIt out_;
+  enum { buffer_size = 256 };
+  T data_[buffer_size];
+
+ protected:
+  void grow(size_t) final FMT_OVERRIDE {
+    if (this->size() == buffer_size) flush();
+  }
+  void flush();
+
+ public:
+  explicit iterator_buffer(OutputIt out, size_t n = buffer_size)
+      : Traits(n),
+        buffer<T>(data_, 0, n < size_t(buffer_size) ? n : size_t(buffer_size)),
+        out_(out) {}
+  ~iterator_buffer() { flush(); }
+
+  OutputIt out() {
+    flush();
+    return out_;
+  }
+  size_t count() const { return Traits::count() + this->size(); }
+};
+
+template <typename T> class iterator_buffer<T*, T> final : public buffer<T> {
+ protected:
+  void grow(size_t) final FMT_OVERRIDE {}
+
+ public:
+  explicit iterator_buffer(T* out, size_t = 0) : buffer<T>(out, 0, ~size_t()) {}
+
+  T* out() { return &*this->end(); }
+};
+
+// A buffer that writes to a container with the contiguous storage.
 template <typename Container>
-class container_buffer : public buffer<typename Container::value_type> {
+class iterator_buffer<std::back_insert_iterator<Container>,
+                      enable_if_t<is_contiguous<Container>::value,
+                                  typename Container::value_type>>
+    final : public buffer<typename Container::value_type> {
  private:
   Container& container_;
 
  protected:
-  void grow(std::size_t capacity) FMT_OVERRIDE {
+  void grow(size_t capacity) final FMT_OVERRIDE {
     container_.resize(capacity);
     this->set(&container_[0], capacity);
   }
 
  public:
-  explicit container_buffer(Container& c)
+  explicit iterator_buffer(Container& c)
       : buffer<typename Container::value_type>(c.size()), container_(c) {}
+  explicit iterator_buffer(std::back_insert_iterator<Container> out, size_t = 0)
+      : iterator_buffer(get_container(out)) {}
+  std::back_insert_iterator<Container> out() {
+    return std::back_inserter(container_);
+  }
 };
 
-// Extracts a reference to the container from back_insert_iterator.
-template <typename Container>
-inline Container& get_container(std::back_insert_iterator<Container> it) {
-  using bi_iterator = std::back_insert_iterator<Container>;
-  struct accessor : bi_iterator {
-    accessor(bi_iterator iter) : bi_iterator(iter) {}
-    using bi_iterator::container;
-  };
-  return *accessor(it).container;
+// A buffer that counts the number of code units written discarding the output.
+template <typename T = char> class counting_buffer final : public buffer<T> {
+ private:
+  enum { buffer_size = 256 };
+  T data_[buffer_size];
+  size_t count_ = 0;
+
+ protected:
+  void grow(size_t) final FMT_OVERRIDE {
+    if (this->size() != buffer_size) return;
+    count_ += this->size();
+    this->clear();
+  }
+
+ public:
+  counting_buffer() : buffer<T>(data_, 0, buffer_size) {}
+
+  size_t count() { return count_ + this->size(); }
+};
+
+// An output iterator that appends to the buffer.
+// It is used to reduce symbol sizes for the common case.
+template <typename T>
+class buffer_appender : public std::back_insert_iterator<buffer<T>> {
+  using base = std::back_insert_iterator<buffer<T>>;
+
+ public:
+  explicit buffer_appender(buffer<T>& buf) : base(buf) {}
+  buffer_appender(base it) : base(it) {}
+
+  buffer_appender& operator++() {
+    base::operator++();
+    return *this;
+  }
+
+  buffer_appender operator++(int) {
+    buffer_appender tmp = *this;
+    ++*this;
+    return tmp;
+  }
+};
+
+// Maps an output iterator into a buffer.
+template <typename T, typename OutputIt>
+iterator_buffer<OutputIt, T> get_buffer(OutputIt);
+template <typename T> buffer<T>& get_buffer(buffer_appender<T>);
+
+template <typename OutputIt> OutputIt get_buffer_init(OutputIt out) {
+  return out;
+}
+template <typename T> buffer<T>& get_buffer_init(buffer_appender<T> out) {
+  return get_container(out);
+}
+
+template <typename Buffer>
+auto get_iterator(Buffer& buf) -> decltype(buf.out()) {
+  return buf.out();
+}
+template <typename T> buffer_appender<T> get_iterator(buffer<T>& buf) {
+  return buffer_appender<T>(buf);
 }
 
 template <typename T, typename Char = char, typename Enable = void>
@@ -681,12 +902,80 @@ template <typename T, typename Context>
 using has_fallback_formatter =
     std::is_constructible<fallback_formatter<T, typename Context::char_type>>;
 
-template <typename Char> struct named_arg_base;
-template <typename T, typename Char> struct named_arg;
+struct view {};
+
+template <typename Char, typename T> struct named_arg : view {
+  const Char* name;
+  const T& value;
+  named_arg(const Char* n, const T& v) : name(n), value(v) {}
+};
 
-enum type {
+template <typename Char> struct named_arg_info {
+  const Char* name;
+  int id;
+};
+
+template <typename T, typename Char, size_t NUM_ARGS, size_t NUM_NAMED_ARGS>
+struct arg_data {
+  // args_[0].named_args points to named_args_ to avoid bloating format_args.
+  // +1 to workaround a bug in gcc 7.5 that causes duplicated-branches warning.
+  T args_[1 + (NUM_ARGS != 0 ? NUM_ARGS : +1)];
+  named_arg_info<Char> named_args_[NUM_NAMED_ARGS];
+
+  template <typename... U>
+  arg_data(const U&... init) : args_{T(named_args_, NUM_NAMED_ARGS), init...} {}
+  arg_data(const arg_data& other) = delete;
+  const T* args() const { return args_ + 1; }
+  named_arg_info<Char>* named_args() { return named_args_; }
+};
+
+template <typename T, typename Char, size_t NUM_ARGS>
+struct arg_data<T, Char, NUM_ARGS, 0> {
+  // +1 to workaround a bug in gcc 7.5 that causes duplicated-branches warning.
+  T args_[NUM_ARGS != 0 ? NUM_ARGS : +1];
+
+  template <typename... U>
+  FMT_INLINE arg_data(const U&... init) : args_{init...} {}
+  FMT_INLINE const T* args() const { return args_; }
+  FMT_INLINE std::nullptr_t named_args() { return nullptr; }
+};
+
+template <typename Char>
+inline void init_named_args(named_arg_info<Char>*, int, int) {}
+
+template <typename Char, typename T, typename... Tail>
+void init_named_args(named_arg_info<Char>* named_args, int arg_count,
+                     int named_arg_count, const T&, const Tail&... args) {
+  init_named_args(named_args, arg_count + 1, named_arg_count, args...);
+}
+
+template <typename Char, typename T, typename... Tail>
+void init_named_args(named_arg_info<Char>* named_args, int arg_count,
+                     int named_arg_count, const named_arg<Char, T>& arg,
+                     const Tail&... args) {
+  named_args[named_arg_count++] = {arg.name, arg_count};
+  init_named_args(named_args, arg_count + 1, named_arg_count, args...);
+}
+
+template <typename... Args>
+FMT_INLINE void init_named_args(std::nullptr_t, int, int, const Args&...) {}
+
+template <typename T> struct is_named_arg : std::false_type {};
+
+template <typename T, typename Char>
+struct is_named_arg<named_arg<Char, T>> : std::true_type {};
+
+template <bool B = false> constexpr size_t count() { return B ? 1 : 0; }
+template <bool B1, bool B2, bool... Tail> constexpr size_t count() {
+  return (B1 ? 1 : 0) + count<B2, Tail...>();
+}
+
+template <typename... Args> constexpr size_t count_named_args() {
+  return count<is_named_arg<Args>::value...>();
+}
+
+enum class type {
   none_type,
-  named_arg_type,
   // Integer types should go first,
   int_type,
   uint_type,
@@ -710,13 +999,13 @@ enum type {
 
 // Maps core type T to the corresponding type enum constant.
 template <typename T, typename Char>
-struct type_constant : std::integral_constant<type, custom_type> {};
+struct type_constant : std::integral_constant<type, type::custom_type> {};
 
 #define FMT_TYPE_CONSTANT(Type, constant) \
   template <typename Char>                \
-  struct type_constant<Type, Char> : std::integral_constant<type, constant> {}
+  struct type_constant<Type, Char>        \
+      : std::integral_constant<type, type::constant> {}
 
-FMT_TYPE_CONSTANT(const named_arg_base<Char>&, named_arg_type);
 FMT_TYPE_CONSTANT(int, int_type);
 FMT_TYPE_CONSTANT(unsigned, uint_type);
 FMT_TYPE_CONSTANT(long long, long_long_type);
@@ -732,23 +1021,26 @@ FMT_TYPE_CONSTANT(const Char*, cstring_type);
 FMT_TYPE_CONSTANT(basic_string_view<Char>, string_type);
 FMT_TYPE_CONSTANT(const void*, pointer_type);
 
-FMT_CONSTEXPR bool is_integral_type(type t) {
-  FMT_ASSERT(t != named_arg_type, "invalid argument type");
-  return t > none_type && t <= last_integer_type;
+constexpr bool is_integral_type(type t) {
+  return t > type::none_type && t <= type::last_integer_type;
 }
 
-FMT_CONSTEXPR bool is_arithmetic_type(type t) {
-  FMT_ASSERT(t != named_arg_type, "invalid argument type");
-  return t > none_type && t <= last_numeric_type;
+constexpr bool is_arithmetic_type(type t) {
+  return t > type::none_type && t <= type::last_numeric_type;
 }
 
 template <typename Char> struct string_value {
   const Char* data;
-  std::size_t size;
+  size_t size;
+};
+
+template <typename Char> struct named_arg_value {
+  const named_arg_info<Char>* data;
+  size_t size;
 };
 
 template <typename Context> struct custom_value {
-  using parse_context = basic_format_parse_context<typename Context::char_type>;
+  using parse_context = typename Context::parse_context_type;
   const void* value;
   void (*format)(const void* arg, parse_context& parse_ctx, Context& ctx);
 };
@@ -773,28 +1065,30 @@ template <typename Context> class value {
     const void* pointer;
     string_value<char_type> string;
     custom_value<Context> custom;
-    const named_arg_base<char_type>* named_arg;
+    named_arg_value<char_type> named_args;
   };
 
-  FMT_CONSTEXPR value(int val = 0) : int_value(val) {}
-  FMT_CONSTEXPR value(unsigned val) : uint_value(val) {}
-  value(long long val) : long_long_value(val) {}
-  value(unsigned long long val) : ulong_long_value(val) {}
-  value(int128_t val) : int128_value(val) {}
-  value(uint128_t val) : uint128_value(val) {}
-  value(float val) : float_value(val) {}
-  value(double val) : double_value(val) {}
-  value(long double val) : long_double_value(val) {}
-  value(bool val) : bool_value(val) {}
-  value(char_type val) : char_value(val) {}
-  value(const char_type* val) { string.data = val; }
-  value(basic_string_view<char_type> val) {
+  constexpr FMT_INLINE value(int val = 0) : int_value(val) {}
+  constexpr FMT_INLINE value(unsigned val) : uint_value(val) {}
+  FMT_INLINE value(long long val) : long_long_value(val) {}
+  FMT_INLINE value(unsigned long long val) : ulong_long_value(val) {}
+  FMT_INLINE value(int128_t val) : int128_value(val) {}
+  FMT_INLINE value(uint128_t val) : uint128_value(val) {}
+  FMT_INLINE value(float val) : float_value(val) {}
+  FMT_INLINE value(double val) : double_value(val) {}
+  FMT_INLINE value(long double val) : long_double_value(val) {}
+  FMT_INLINE value(bool val) : bool_value(val) {}
+  FMT_INLINE value(char_type val) : char_value(val) {}
+  FMT_INLINE value(const char_type* val) { string.data = val; }
+  FMT_INLINE value(basic_string_view<char_type> val) {
     string.data = val.data();
     string.size = val.size();
   }
-  value(const void* val) : pointer(val) {}
+  FMT_INLINE value(const void* val) : pointer(val) {}
+  FMT_INLINE value(const named_arg_info<char_type>* args, size_t size)
+      : named_args{args, size} {}
 
-  template <typename T> value(const T& val) {
+  template <typename T> FMT_INLINE value(const T& val) {
     custom.value = &val;
     // Get the formatter type through the context to allow different contexts
     // have different extension points, e.g. `formatter<T>` for `format` and
@@ -805,14 +1099,12 @@ template <typename Context> class value {
                          fallback_formatter<T, char_type>>>;
   }
 
-  value(const named_arg_base<char_type>& val) { named_arg = &val; }
-
  private:
   // Formats an argument of a custom type, such as a user-defined class.
   template <typename T, typename Formatter>
-  static void format_custom_arg(
-      const void* arg, basic_format_parse_context<char_type>& parse_ctx,
-      Context& ctx) {
+  static void format_custom_arg(const void* arg,
+                                typename Context::parse_context_type& parse_ctx,
+                                Context& ctx) {
     Formatter f;
     parse_ctx.advance_to(f.parse(parse_ctx));
     ctx.advance_to(f.format(*static_cast<const T*>(arg), ctx));
@@ -828,6 +1120,8 @@ enum { long_short = sizeof(long) == sizeof(int) };
 using long_type = conditional_t<long_short, int, long long>;
 using ulong_type = conditional_t<long_short, unsigned, unsigned long long>;
 
+struct unformattable {};
+
 // Maps formatting arguments to core types.
 template <typename Context> struct arg_mapper {
   using char_type = typename Context::char_type;
@@ -869,7 +1163,8 @@ template <typename Context> struct arg_mapper {
   template <typename T,
             FMT_ENABLE_IF(
                 std::is_constructible<basic_string_view<char_type>, T>::value &&
-                !is_string<T>::value)>
+                !is_string<T>::value && !has_formatter<T, Context>::value &&
+                !has_fallback_formatter<T, Context>::value)>
   FMT_CONSTEXPR basic_string_view<char_type> map(const T& val) {
     return basic_string_view<char_type>(val);
   }
@@ -878,7 +1173,8 @@ template <typename Context> struct arg_mapper {
       FMT_ENABLE_IF(
           std::is_constructible<std_string_view<char_type>, T>::value &&
           !std::is_constructible<basic_string_view<char_type>, T>::value &&
-          !is_string<T>::value && !has_formatter<T, Context>::value)>
+          !is_string<T>::value && !has_formatter<T, Context>::value &&
+          !has_fallback_formatter<T, Context>::value)>
   FMT_CONSTEXPR basic_string_view<char_type> map(const T& val) {
     return std_string_view<char_type>(val);
   }
@@ -890,6 +1186,14 @@ template <typename Context> struct arg_mapper {
     static_assert(std::is_same<char_type, char>::value, "invalid string type");
     return reinterpret_cast<const char*>(val);
   }
+  FMT_CONSTEXPR const char* map(signed char* val) {
+    const auto* const_val = val;
+    return map(const_val);
+  }
+  FMT_CONSTEXPR const char* map(unsigned char* val) {
+    const auto* const_val = val;
+    return map(const_val);
+  }
 
   FMT_CONSTEXPR const void* map(void* val) { return val; }
   FMT_CONSTEXPR const void* map(const void* val) { return val; }
@@ -907,29 +1211,26 @@ template <typename Context> struct arg_mapper {
             FMT_ENABLE_IF(std::is_enum<T>::value &&
                           !has_formatter<T, Context>::value &&
                           !has_fallback_formatter<T, Context>::value)>
-  FMT_CONSTEXPR auto map(const T& val) -> decltype(
-      map(static_cast<typename std::underlying_type<T>::type>(val))) {
+  FMT_CONSTEXPR auto map(const T& val)
+      -> decltype(std::declval<arg_mapper>().map(
+          static_cast<typename std::underlying_type<T>::type>(val))) {
     return map(static_cast<typename std::underlying_type<T>::type>(val));
   }
-  template <
-      typename T,
-      FMT_ENABLE_IF(
-          !is_string<T>::value && !is_char<T>::value &&
-          !std::is_constructible<basic_string_view<char_type>, T>::value &&
-          (has_formatter<T, Context>::value ||
-           (has_fallback_formatter<T, Context>::value &&
-            !std::is_constructible<std_string_view<char_type>, T>::value)))>
+  template <typename T,
+            FMT_ENABLE_IF(!is_string<T>::value && !is_char<T>::value &&
+                          (has_formatter<T, Context>::value ||
+                           has_fallback_formatter<T, Context>::value))>
   FMT_CONSTEXPR const T& map(const T& val) {
     return val;
   }
 
   template <typename T>
-  FMT_CONSTEXPR const named_arg_base<char_type>& map(
-      const named_arg<T, char_type>& val) {
-    auto arg = make_arg<Context>(val.value);
-    std::memcpy(val.data, &arg, sizeof(arg));
-    return val;
+  FMT_CONSTEXPR auto map(const named_arg<char_type, T>& val)
+      -> decltype(std::declval<arg_mapper>().map(val.value)) {
+    return map(val.value);
   }
+
+  unformattable map(...) { return {}; }
 };
 
 // A type constant after applying arg_mapper<Context>.
@@ -938,23 +1239,22 @@ using mapped_type_constant =
     type_constant<decltype(arg_mapper<Context>().map(std::declval<const T&>())),
                   typename Context::char_type>;
 
-enum { packed_arg_bits = 5 };
+enum { packed_arg_bits = 4 };
 // Maximum number of arguments with packed types.
-enum { max_packed_args = 63 / packed_arg_bits };
+enum { max_packed_args = 62 / packed_arg_bits };
 enum : unsigned long long { is_unpacked_bit = 1ULL << 63 };
-
-template <typename Context> class arg_map;
-}  // namespace internal
+enum : unsigned long long { has_named_args_bit = 1ULL << 62 };
+}  // namespace detail
 
 // A formatting argument. It is a trivially copyable/constructible type to
 // allow storage in basic_memory_buffer.
 template <typename Context> class basic_format_arg {
  private:
-  internal::value<Context> value_;
-  internal::type type_;
+  detail::value<Context> value_;
+  detail::type type_;
 
   template <typename ContextType, typename T>
-  friend FMT_CONSTEXPR basic_format_arg<ContextType> internal::make_arg(
+  friend FMT_CONSTEXPR basic_format_arg<ContextType> detail::make_arg(
       const T& value);
 
   template <typename Visitor, typename Ctx>
@@ -963,34 +1263,40 @@ template <typename Context> class basic_format_arg {
       -> decltype(vis(0));
 
   friend class basic_format_args<Context>;
-  friend class internal::arg_map<Context>;
+  friend class dynamic_format_arg_store<Context>;
 
   using char_type = typename Context::char_type;
 
+  template <typename T, typename Char, size_t NUM_ARGS, size_t NUM_NAMED_ARGS>
+  friend struct detail::arg_data;
+
+  basic_format_arg(const detail::named_arg_info<char_type>* args, size_t size)
+      : value_(args, size) {}
+
  public:
   class handle {
    public:
-    explicit handle(internal::custom_value<Context> custom) : custom_(custom) {}
+    explicit handle(detail::custom_value<Context> custom) : custom_(custom) {}
 
-    void format(basic_format_parse_context<char_type>& parse_ctx,
+    void format(typename Context::parse_context_type& parse_ctx,
                 Context& ctx) const {
       custom_.format(custom_.value, parse_ctx, ctx);
     }
 
    private:
-    internal::custom_value<Context> custom_;
+    detail::custom_value<Context> custom_;
   };
 
-  FMT_CONSTEXPR basic_format_arg() : type_(internal::none_type) {}
+  constexpr basic_format_arg() : type_(detail::type::none_type) {}
 
-  FMT_CONSTEXPR explicit operator bool() const FMT_NOEXCEPT {
-    return type_ != internal::none_type;
+  constexpr explicit operator bool() const FMT_NOEXCEPT {
+    return type_ != detail::type::none_type;
   }
 
-  internal::type type() const { return type_; }
+  detail::type type() const { return type_; }
 
-  bool is_integral() const { return internal::is_integral_type(type_); }
-  bool is_arithmetic() const { return internal::is_arithmetic_type(type_); }
+  bool is_integral() const { return detail::is_integral_type(type_); }
+  bool is_arithmetic() const { return detail::is_arithmetic_type(type_); }
 };
 
 /**
@@ -1001,92 +1307,86 @@ template <typename Context> class basic_format_arg {
   \endrst
  */
 template <typename Visitor, typename Context>
-FMT_CONSTEXPR auto visit_format_arg(Visitor&& vis,
-                                    const basic_format_arg<Context>& arg)
-    -> decltype(vis(0)) {
+FMT_CONSTEXPR_DECL FMT_INLINE auto visit_format_arg(
+    Visitor&& vis, const basic_format_arg<Context>& arg) -> decltype(vis(0)) {
   using char_type = typename Context::char_type;
   switch (arg.type_) {
-  case internal::none_type:
-    break;
-  case internal::named_arg_type:
-    FMT_ASSERT(false, "invalid argument type");
+  case detail::type::none_type:
     break;
-  case internal::int_type:
+  case detail::type::int_type:
     return vis(arg.value_.int_value);
-  case internal::uint_type:
+  case detail::type::uint_type:
     return vis(arg.value_.uint_value);
-  case internal::long_long_type:
+  case detail::type::long_long_type:
     return vis(arg.value_.long_long_value);
-  case internal::ulong_long_type:
+  case detail::type::ulong_long_type:
     return vis(arg.value_.ulong_long_value);
 #if FMT_USE_INT128
-  case internal::int128_type:
+  case detail::type::int128_type:
     return vis(arg.value_.int128_value);
-  case internal::uint128_type:
+  case detail::type::uint128_type:
     return vis(arg.value_.uint128_value);
 #else
-  case internal::int128_type:
-  case internal::uint128_type:
+  case detail::type::int128_type:
+  case detail::type::uint128_type:
     break;
 #endif
-  case internal::bool_type:
+  case detail::type::bool_type:
     return vis(arg.value_.bool_value);
-  case internal::char_type:
+  case detail::type::char_type:
     return vis(arg.value_.char_value);
-  case internal::float_type:
+  case detail::type::float_type:
     return vis(arg.value_.float_value);
-  case internal::double_type:
+  case detail::type::double_type:
     return vis(arg.value_.double_value);
-  case internal::long_double_type:
+  case detail::type::long_double_type:
     return vis(arg.value_.long_double_value);
-  case internal::cstring_type:
+  case detail::type::cstring_type:
     return vis(arg.value_.string.data);
-  case internal::string_type:
+  case detail::type::string_type:
     return vis(basic_string_view<char_type>(arg.value_.string.data,
                                             arg.value_.string.size));
-  case internal::pointer_type:
+  case detail::type::pointer_type:
     return vis(arg.value_.pointer);
-  case internal::custom_type:
+  case detail::type::custom_type:
     return vis(typename basic_format_arg<Context>::handle(arg.value_.custom));
   }
   return vis(monostate());
 }
 
-namespace internal {
-// A map from argument names to their values for named arguments.
-template <typename Context> class arg_map {
- private:
-  using char_type = typename Context::char_type;
+template <typename T> struct formattable : std::false_type {};
 
-  struct entry {
-    basic_string_view<char_type> name;
-    basic_format_arg<Context> arg;
-  };
+namespace detail {
+
+// A workaround for gcc 4.8 to make void_t work in a SFINAE context.
+template <typename... Ts> struct void_t_impl { using type = void; };
+template <typename... Ts>
+using void_t = typename detail::void_t_impl<Ts...>::type;
 
-  entry* map_;
-  unsigned size_;
+template <typename It, typename T, typename Enable = void>
+struct is_output_iterator : std::false_type {};
 
-  void push_back(value<Context> val) {
-    const auto& named = *val.named_arg;
-    map_[size_] = {named.name, named.template deserialize<Context>()};
-    ++size_;
-  }
+template <typename It, typename T>
+struct is_output_iterator<
+    It, T,
+    void_t<typename std::iterator_traits<It>::iterator_category,
+           decltype(*std::declval<It>() = std::declval<T>())>>
+    : std::true_type {};
 
- public:
-  arg_map(const arg_map&) = delete;
-  void operator=(const arg_map&) = delete;
-  arg_map() : map_(nullptr), size_(0) {}
-  void init(const basic_format_args<Context>& args);
-  ~arg_map() { delete[] map_; }
-
-  basic_format_arg<Context> find(basic_string_view<char_type> name) const {
-    // The list is unsorted, so just return the first matching name.
-    for (entry *it = map_, *end = map_ + size_; it != end; ++it) {
-      if (it->name == name) return it->arg;
-    }
-    return {};
-  }
-};
+template <typename OutputIt>
+struct is_back_insert_iterator : std::false_type {};
+template <typename Container>
+struct is_back_insert_iterator<std::back_insert_iterator<Container>>
+    : std::true_type {};
+
+template <typename OutputIt>
+struct is_contiguous_back_insert_iterator : std::false_type {};
+template <typename Container>
+struct is_contiguous_back_insert_iterator<std::back_insert_iterator<Container>>
+    : is_contiguous<Container> {};
+template <typename Char>
+struct is_contiguous_back_insert_iterator<buffer_appender<Char>>
+    : std::true_type {};
 
 // A type-erased reference to an std::locale to avoid heavy <locale> include.
 class locale_ref {
@@ -1106,7 +1406,7 @@ template <typename> constexpr unsigned long long encode_types() { return 0; }
 
 template <typename Context, typename Arg, typename... Args>
 constexpr unsigned long long encode_types() {
-  return mapped_type_constant<Arg, Context>::value |
+  return static_cast<unsigned>(mapped_type_constant<Arg, Context>::value) |
          (encode_types<Context, Args...>() << packed_arg_bits);
 }
 
@@ -1118,18 +1418,73 @@ FMT_CONSTEXPR basic_format_arg<Context> make_arg(const T& value) {
   return arg;
 }
 
-template <bool IS_PACKED, typename Context, typename T,
+template <typename T> int check(unformattable) {
+  static_assert(
+      formattable<T>(),
+      "Cannot format an argument. To make type T formattable provide a "
+      "formatter<T> specialization: https://fmt.dev/latest/api.html#udt");
+  return 0;
+}
+template <typename T, typename U> inline const U& check(const U& val) {
+  return val;
+}
+
+// The type template parameter is there to avoid an ODR violation when using
+// a fallback formatter in one translation unit and an implicit conversion in
+// another (not recommended).
+template <bool IS_PACKED, typename Context, type, typename T,
           FMT_ENABLE_IF(IS_PACKED)>
 inline value<Context> make_arg(const T& val) {
-  return arg_mapper<Context>().map(val);
+  return check<T>(arg_mapper<Context>().map(val));
 }
 
-template <bool IS_PACKED, typename Context, typename T,
+template <bool IS_PACKED, typename Context, type, typename T,
           FMT_ENABLE_IF(!IS_PACKED)>
 inline basic_format_arg<Context> make_arg(const T& value) {
   return make_arg<Context>(value);
 }
-}  // namespace internal
+
+template <typename T> struct is_reference_wrapper : std::false_type {};
+template <typename T>
+struct is_reference_wrapper<std::reference_wrapper<T>> : std::true_type {};
+
+template <typename T> const T& unwrap(const T& v) { return v; }
+template <typename T> const T& unwrap(const std::reference_wrapper<T>& v) {
+  return static_cast<const T&>(v);
+}
+
+class dynamic_arg_list {
+  // Workaround for clang's -Wweak-vtables. Unlike for regular classes, for
+  // templates it doesn't complain about inability to deduce single translation
+  // unit for placing vtable. So storage_node_base is made a fake template.
+  template <typename = void> struct node {
+    virtual ~node() = default;
+    std::unique_ptr<node<>> next;
+  };
+
+  template <typename T> struct typed_node : node<> {
+    T value;
+
+    template <typename Arg>
+    FMT_CONSTEXPR typed_node(const Arg& arg) : value(arg) {}
+
+    template <typename Char>
+    FMT_CONSTEXPR typed_node(const basic_string_view<Char>& arg)
+        : value(arg.data(), arg.size()) {}
+  };
+
+  std::unique_ptr<node<>> head_;
+
+ public:
+  template <typename T, typename Arg> const T& push(const Arg& arg) {
+    auto new_node = std::unique_ptr<typed_node<T>>(new typed_node<T>(arg));
+    auto& value = new_node->value;
+    new_node->next = std::move(head_);
+    head_ = std::move(new_node);
+    return value;
+  }
+};
+}  // namespace detail
 
 // Formatting context.
 template <typename OutputIt, typename Char> class basic_format_context {
@@ -1140,12 +1495,12 @@ template <typename OutputIt, typename Char> class basic_format_context {
  private:
   OutputIt out_;
   basic_format_args<basic_format_context> args_;
-  internal::arg_map<basic_format_context> map_;
-  internal::locale_ref loc_;
+  detail::locale_ref loc_;
 
  public:
   using iterator = OutputIt;
   using format_arg = basic_format_arg<basic_format_context>;
+  using parse_context_type = basic_format_parse_context<Char>;
   template <typename T> using formatter_type = formatter<T, char_type>;
 
   basic_format_context(const basic_format_context&) = delete;
@@ -1156,34 +1511,38 @@ template <typename OutputIt, typename Char> class basic_format_context {
    */
   basic_format_context(OutputIt out,
                        basic_format_args<basic_format_context> ctx_args,
-                       internal::locale_ref loc = internal::locale_ref())
+                       detail::locale_ref loc = detail::locale_ref())
       : out_(out), args_(ctx_args), loc_(loc) {}
 
   format_arg arg(int id) const { return args_.get(id); }
+  format_arg arg(basic_string_view<char_type> name) { return args_.get(name); }
+  int arg_id(basic_string_view<char_type> name) { return args_.get_id(name); }
+  const basic_format_args<basic_format_context>& args() const { return args_; }
 
-  // Checks if manual indexing is used and returns the argument with the
-  // specified name.
-  format_arg arg(basic_string_view<char_type> name);
-
-  internal::error_handler error_handler() { return {}; }
+  detail::error_handler error_handler() { return {}; }
   void on_error(const char* message) { error_handler().on_error(message); }
 
   // Returns an iterator to the beginning of the output range.
   iterator out() { return out_; }
 
   // Advances the begin iterator to ``it``.
-  void advance_to(iterator it) { out_ = it; }
+  void advance_to(iterator it) {
+    if (!detail::is_back_insert_iterator<iterator>()) out_ = it;
+  }
 
-  internal::locale_ref locale() { return loc_; }
+  detail::locale_ref locale() { return loc_; }
 };
 
 template <typename Char>
 using buffer_context =
-    basic_format_context<std::back_insert_iterator<internal::buffer<Char>>,
-                         Char>;
+    basic_format_context<detail::buffer_appender<Char>, Char>;
 using format_context = buffer_context<char>;
 using wformat_context = buffer_context<wchar_t>;
 
+// Workaround an alias issue: https://stackoverflow.com/q/62767544/471164.
+#define FMT_BUFFER_CONTEXT(Char) \
+  basic_format_context<detail::buffer_appender<Char>, Char>
+
 /**
   \rst
   An array of references to arguments. It can be implicitly converted into
@@ -1191,31 +1550,50 @@ using wformat_context = buffer_context<wchar_t>;
   such as `~fmt::vformat`.
   \endrst
  */
-template <typename Context, typename... Args> class format_arg_store {
+template <typename Context, typename... Args>
+class format_arg_store
+#if FMT_GCC_VERSION && FMT_GCC_VERSION < 409
+    // Workaround a GCC template argument substitution bug.
+    : public basic_format_args<Context>
+#endif
+{
  private:
   static const size_t num_args = sizeof...(Args);
-  static const bool is_packed = num_args < internal::max_packed_args;
+  static const size_t num_named_args = detail::count_named_args<Args...>();
+  static const bool is_packed = num_args <= detail::max_packed_args;
 
-  using value_type = conditional_t<is_packed, internal::value<Context>,
+  using value_type = conditional_t<is_packed, detail::value<Context>,
                                    basic_format_arg<Context>>;
 
-  // If the arguments are not packed, add one more element to mark the end.
-  value_type data_[num_args + (num_args == 0 ? 1 : 0)];
+  detail::arg_data<value_type, typename Context::char_type, num_args,
+                   num_named_args>
+      data_;
 
   friend class basic_format_args<Context>;
 
- public:
-  static constexpr unsigned long long types =
-      is_packed ? internal::encode_types<Context, Args...>()
-                : internal::is_unpacked_bit | num_args;
+  static constexpr unsigned long long desc =
+      (is_packed ? detail::encode_types<Context, Args...>()
+                 : detail::is_unpacked_bit | num_args) |
+      (num_named_args != 0
+           ? static_cast<unsigned long long>(detail::has_named_args_bit)
+           : 0);
 
+ public:
   format_arg_store(const Args&... args)
-      : data_{internal::make_arg<is_packed, Context>(args)...} {}
+      :
+#if FMT_GCC_VERSION && FMT_GCC_VERSION < 409
+        basic_format_args<Context>(*this),
+#endif
+        data_{detail::make_arg<
+            is_packed, Context,
+            detail::mapped_type_constant<Args, Context>::value>(args)...} {
+    detail::init_named_args(data_.named_args(), 0, 0, args...);
+  }
 };
 
 /**
   \rst
-  Constructs an `~fmt::format_arg_store` object that contains references to
+  Constructs a `~fmt::format_arg_store` object that contains references to
   arguments and can be implicitly converted to `~fmt::format_args`. `Context`
   can be omitted in which case it defaults to `~fmt::context`.
   See `~fmt::arg` for lifetime considerations.
@@ -1227,56 +1605,266 @@ inline format_arg_store<Context, Args...> make_format_args(
   return {args...};
 }
 
-/** Formatting arguments. */
+/**
+  \rst
+  Constructs a `~fmt::format_arg_store` object that contains references
+  to arguments and can be implicitly converted to `~fmt::format_args`.
+  If ``format_str`` is a compile-time string then `make_args_checked` checks
+  its validity at compile time.
+  \endrst
+ */
+template <typename... Args, typename S, typename Char = char_t<S>>
+inline auto make_args_checked(const S& format_str,
+                              const remove_reference_t<Args>&... args)
+    -> format_arg_store<buffer_context<Char>, remove_reference_t<Args>...> {
+  static_assert(
+      detail::count<(
+              std::is_base_of<detail::view, remove_reference_t<Args>>::value &&
+              std::is_reference<Args>::value)...>() == 0,
+      "passing views as lvalues is disallowed");
+  detail::check_format_string<Args...>(format_str);
+  return {args...};
+}
+
+/**
+  \rst
+  Returns a named argument to be used in a formatting function. It should only
+  be used in a call to a formatting function.
+
+  **Example**::
+
+    fmt::print("Elapsed time: {s:.2f} seconds", fmt::arg("s", 1.23));
+  \endrst
+ */
+template <typename Char, typename T>
+inline detail::named_arg<Char, T> arg(const Char* name, const T& arg) {
+  static_assert(!detail::is_named_arg<T>(), "nested named arguments");
+  return {name, arg};
+}
+
+/**
+  \rst
+  A dynamic version of `fmt::format_arg_store`.
+  It's equipped with a storage to potentially temporary objects which lifetimes
+  could be shorter than the format arguments object.
+
+  It can be implicitly converted into `~fmt::basic_format_args` for passing
+  into type-erased formatting functions such as `~fmt::vformat`.
+  \endrst
+ */
+template <typename Context>
+class dynamic_format_arg_store
+#if FMT_GCC_VERSION && FMT_GCC_VERSION < 409
+    // Workaround a GCC template argument substitution bug.
+    : public basic_format_args<Context>
+#endif
+{
+ private:
+  using char_type = typename Context::char_type;
+
+  template <typename T> struct need_copy {
+    static constexpr detail::type mapped_type =
+        detail::mapped_type_constant<T, Context>::value;
+
+    enum {
+      value = !(detail::is_reference_wrapper<T>::value ||
+                std::is_same<T, basic_string_view<char_type>>::value ||
+                std::is_same<T, detail::std_string_view<char_type>>::value ||
+                (mapped_type != detail::type::cstring_type &&
+                 mapped_type != detail::type::string_type &&
+                 mapped_type != detail::type::custom_type))
+    };
+  };
+
+  template <typename T>
+  using stored_type = conditional_t<detail::is_string<T>::value,
+                                    std::basic_string<char_type>, T>;
+
+  // Storage of basic_format_arg must be contiguous.
+  std::vector<basic_format_arg<Context>> data_;
+  std::vector<detail::named_arg_info<char_type>> named_info_;
+
+  // Storage of arguments not fitting into basic_format_arg must grow
+  // without relocation because items in data_ refer to it.
+  detail::dynamic_arg_list dynamic_args_;
+
+  friend class basic_format_args<Context>;
+
+  unsigned long long get_types() const {
+    return detail::is_unpacked_bit | data_.size() |
+           (named_info_.empty()
+                ? 0ULL
+                : static_cast<unsigned long long>(detail::has_named_args_bit));
+  }
+
+  const basic_format_arg<Context>* data() const {
+    return named_info_.empty() ? data_.data() : data_.data() + 1;
+  }
+
+  template <typename T> void emplace_arg(const T& arg) {
+    data_.emplace_back(detail::make_arg<Context>(arg));
+  }
+
+  template <typename T>
+  void emplace_arg(const detail::named_arg<char_type, T>& arg) {
+    if (named_info_.empty()) {
+      constexpr const detail::named_arg_info<char_type>* zero_ptr{nullptr};
+      data_.insert(data_.begin(), {zero_ptr, 0});
+    }
+    data_.emplace_back(detail::make_arg<Context>(detail::unwrap(arg.value)));
+    auto pop_one = [](std::vector<basic_format_arg<Context>>* data) {
+      data->pop_back();
+    };
+    std::unique_ptr<std::vector<basic_format_arg<Context>>, decltype(pop_one)>
+        guard{&data_, pop_one};
+    named_info_.push_back({arg.name, static_cast<int>(data_.size() - 2u)});
+    data_[0].value_.named_args = {named_info_.data(), named_info_.size()};
+    guard.release();
+  }
+
+ public:
+  /**
+    \rst
+    Adds an argument into the dynamic store for later passing to a formatting
+    function.
+
+    Note that custom types and string types (but not string views) are copied
+    into the store dynamically allocating memory if necessary.
+
+    **Example**::
+
+      fmt::dynamic_format_arg_store<fmt::format_context> store;
+      store.push_back(42);
+      store.push_back("abc");
+      store.push_back(1.5f);
+      std::string result = fmt::vformat("{} and {} and {}", store);
+    \endrst
+  */
+  template <typename T> void push_back(const T& arg) {
+    if (detail::const_check(need_copy<T>::value))
+      emplace_arg(dynamic_args_.push<stored_type<T>>(arg));
+    else
+      emplace_arg(detail::unwrap(arg));
+  }
+
+  /**
+    \rst
+    Adds a reference to the argument into the dynamic store for later passing to
+    a formatting function. Supports named arguments wrapped in
+    ``std::reference_wrapper`` via ``std::ref()``/``std::cref()``.
+
+    **Example**::
+
+      fmt::dynamic_format_arg_store<fmt::format_context> store;
+      char str[] = "1234567890";
+      store.push_back(std::cref(str));
+      int a1_val{42};
+      auto a1 = fmt::arg("a1_", a1_val);
+      store.push_back(std::cref(a1));
+
+      // Changing str affects the output but only for string and custom types.
+      str[0] = 'X';
+
+      std::string result = fmt::vformat("{} and {a1_}");
+      assert(result == "X234567890 and 42");
+    \endrst
+  */
+  template <typename T> void push_back(std::reference_wrapper<T> arg) {
+    static_assert(
+        detail::is_named_arg<typename std::remove_cv<T>::type>::value ||
+            need_copy<T>::value,
+        "objects of built-in types and string views are always copied");
+    emplace_arg(arg.get());
+  }
+
+  /**
+    Adds named argument into the dynamic store for later passing to a formatting
+    function. ``std::reference_wrapper`` is supported to avoid copying of the
+    argument.
+  */
+  template <typename T>
+  void push_back(const detail::named_arg<char_type, T>& arg) {
+    const char_type* arg_name =
+        dynamic_args_.push<std::basic_string<char_type>>(arg.name).c_str();
+    if (detail::const_check(need_copy<T>::value)) {
+      emplace_arg(
+          fmt::arg(arg_name, dynamic_args_.push<stored_type<T>>(arg.value)));
+    } else {
+      emplace_arg(fmt::arg(arg_name, arg.value));
+    }
+  }
+
+  /** Erase all elements from the store */
+  void clear() {
+    data_.clear();
+    named_info_.clear();
+    dynamic_args_ = detail::dynamic_arg_list();
+  }
+
+  /**
+    \rst
+    Reserves space to store at least *new_cap* arguments including
+    *new_cap_named* named arguments.
+    \endrst
+  */
+  void reserve(size_t new_cap, size_t new_cap_named) {
+    FMT_ASSERT(new_cap >= new_cap_named,
+               "Set of arguments includes set of named arguments");
+    data_.reserve(new_cap);
+    named_info_.reserve(new_cap_named);
+  }
+};
+
+/**
+  \rst
+  A view of a collection of formatting arguments. To avoid lifetime issues it
+  should only be used as a parameter type in type-erased functions such as
+  ``vformat``::
+
+    void vlog(string_view format_str, format_args args);  // OK
+    format_args args = make_format_args(42);  // Error: dangling reference
+  \endrst
+ */
 template <typename Context> class basic_format_args {
  public:
   using size_type = int;
   using format_arg = basic_format_arg<Context>;
 
  private:
-  // To reduce compiled code size per formatting function call, types of first
-  // max_packed_args arguments are passed in the types_ field.
-  unsigned long long types_;
+  // A descriptor that contains information about formatting arguments.
+  // If the number of arguments is less or equal to max_packed_args then
+  // argument types are passed in the descriptor. This reduces binary code size
+  // per formatting function call.
+  unsigned long long desc_;
   union {
-    // If the number of arguments is less than max_packed_args, the argument
-    // values are stored in values_, otherwise they are stored in args_.
-    // This is done to reduce compiled code size as storing larger objects
+    // If is_packed() returns true then argument values are stored in values_;
+    // otherwise they are stored in args_. This is done to improve cache
+    // locality and reduce compiled code size since storing larger objects
     // may require more code (at least on x86-64) even if the same amount of
     // data is actually copied to stack. It saves ~10% on the bloat test.
-    const internal::value<Context>* values_;
+    const detail::value<Context>* values_;
     const format_arg* args_;
   };
 
-  bool is_packed() const { return (types_ & internal::is_unpacked_bit) == 0; }
-
-  internal::type type(int index) const {
-    int shift = index * internal::packed_arg_bits;
-    unsigned int mask = (1 << internal::packed_arg_bits) - 1;
-    return static_cast<internal::type>((types_ >> shift) & mask);
+  bool is_packed() const { return (desc_ & detail::is_unpacked_bit) == 0; }
+  bool has_named_args() const {
+    return (desc_ & detail::has_named_args_bit) != 0;
   }
 
-  friend class internal::arg_map<Context>;
-
-  void set_data(const internal::value<Context>* values) { values_ = values; }
-  void set_data(const format_arg* args) { args_ = args; }
-
-  format_arg do_get(int index) const {
-    format_arg arg;
-    if (!is_packed()) {
-      auto num_args = max_size();
-      if (index < num_args) arg = args_[index];
-      return arg;
-    }
-    if (index > internal::max_packed_args) return arg;
-    arg.type_ = type(index);
-    if (arg.type_ == internal::none_type) return arg;
-    internal::value<Context>& val = arg.value_;
-    val = values_[index];
-    return arg;
+  detail::type type(int index) const {
+    int shift = index * detail::packed_arg_bits;
+    unsigned int mask = (1 << detail::packed_arg_bits) - 1;
+    return static_cast<detail::type>((desc_ >> shift) & mask);
   }
 
+  basic_format_args(unsigned long long desc,
+                    const detail::value<Context>* values)
+      : desc_(desc), values_(values) {}
+  basic_format_args(unsigned long long desc, const format_arg* args)
+      : desc_(desc), args_(args) {}
+
  public:
-  basic_format_args() : types_(0) {}
+  basic_format_args() : desc_(0) {}
 
   /**
    \rst
@@ -1284,10 +1872,17 @@ template <typename Context> class basic_format_args {
    \endrst
    */
   template <typename... Args>
-  basic_format_args(const format_arg_store<Context, Args...>& store)
-      : types_(store.types) {
-    set_data(store.data_);
-  }
+  FMT_INLINE basic_format_args(const format_arg_store<Context, Args...>& store)
+      : basic_format_args(store.desc, store.data_.args()) {}
+
+  /**
+   \rst
+   Constructs a `basic_format_args` object from
+   `~fmt::dynamic_format_arg_store`.
+   \endrst
+   */
+  FMT_INLINE basic_format_args(const dynamic_format_arg_store<Context>& store)
+      : basic_format_args(store.get_types(), store.data()) {}
 
   /**
    \rst
@@ -1295,22 +1890,42 @@ template <typename Context> class basic_format_args {
    \endrst
    */
   basic_format_args(const format_arg* args, int count)
-      : types_(internal::is_unpacked_bit | internal::to_unsigned(count)) {
-    set_data(args);
-  }
+      : basic_format_args(detail::is_unpacked_bit | detail::to_unsigned(count),
+                          args) {}
 
-  /** Returns the argument at specified index. */
-  format_arg get(int index) const {
-    format_arg arg = do_get(index);
-    if (arg.type_ == internal::named_arg_type)
-      arg = arg.value_.named_arg->template deserialize<Context>();
+  /** Returns the argument with the specified id. */
+  format_arg get(int id) const {
+    format_arg arg;
+    if (!is_packed()) {
+      if (id < max_size()) arg = args_[id];
+      return arg;
+    }
+    if (id >= detail::max_packed_args) return arg;
+    arg.type_ = type(id);
+    if (arg.type_ == detail::type::none_type) return arg;
+    arg.value_ = values_[id];
     return arg;
   }
 
+  template <typename Char> format_arg get(basic_string_view<Char> name) const {
+    int id = get_id(name);
+    return id >= 0 ? get(id) : format_arg();
+  }
+
+  template <typename Char> int get_id(basic_string_view<Char> name) const {
+    if (!has_named_args()) return -1;
+    const auto& named_args =
+        (is_packed() ? values_[-1] : args_[-1].value_).named_args;
+    for (size_t i = 0; i < named_args.size; ++i) {
+      if (named_args.data[i].name == name) return named_args.data[i].id;
+    }
+    return -1;
+  }
+
   int max_size() const {
-    unsigned long long max_packed = internal::max_packed_args;
+    unsigned long long max_packed = detail::max_packed_args;
     return static_cast<int>(is_packed() ? max_packed
-                                        : types_ & ~internal::is_unpacked_bit);
+                                        : desc_ & ~detail::is_unpacked_bit);
   }
 };
 
@@ -1318,145 +1933,121 @@ template <typename Context> class basic_format_args {
 // It is a separate type rather than an alias to make symbols readable.
 struct format_args : basic_format_args<format_context> {
   template <typename... Args>
-  format_args(Args&&... args)
-      : basic_format_args<format_context>(std::forward<Args>(args)...) {}
+  FMT_INLINE format_args(const Args&... args) : basic_format_args(args...) {}
 };
 struct wformat_args : basic_format_args<wformat_context> {
-  template <typename... Args>
-  wformat_args(Args&&... args)
-      : basic_format_args<wformat_context>(std::forward<Args>(args)...) {}
+  using basic_format_args::basic_format_args;
 };
 
-template <typename Container> struct is_contiguous : std::false_type {};
-
-template <typename Char>
-struct is_contiguous<std::basic_string<Char>> : std::true_type {};
-
-template <typename Char>
-struct is_contiguous<internal::buffer<Char>> : std::true_type {};
-
-namespace internal {
+namespace detail {
 
-template <typename OutputIt>
-struct is_contiguous_back_insert_iterator : std::false_type {};
-template <typename Container>
-struct is_contiguous_back_insert_iterator<std::back_insert_iterator<Container>>
-    : is_contiguous<Container> {};
-
-template <typename Char> struct named_arg_base {
-  basic_string_view<Char> name;
-
-  // Serialized value<context>.
-  mutable char data[sizeof(basic_format_arg<buffer_context<Char>>)];
+template <typename Char, FMT_ENABLE_IF(!std::is_same<Char, char>::value)>
+std::basic_string<Char> vformat(
+    basic_string_view<Char> format_str,
+    basic_format_args<buffer_context<type_identity_t<Char>>> args);
 
-  named_arg_base(basic_string_view<Char> nm) : name(nm) {}
+FMT_API std::string vformat(string_view format_str, format_args args);
 
-  template <typename Context> basic_format_arg<Context> deserialize() const {
-    basic_format_arg<Context> arg;
-    std::memcpy(&arg, data, sizeof(basic_format_arg<Context>));
-    return arg;
-  }
-};
+template <typename Char>
+void vformat_to(
+    buffer<Char>& buf, basic_string_view<Char> format_str,
+    basic_format_args<FMT_BUFFER_CONTEXT(type_identity_t<Char>)> args,
+    detail::locale_ref loc = {});
 
-template <typename T, typename Char> struct named_arg : named_arg_base<Char> {
-  const T& value;
+template <typename Char, typename Args,
+          FMT_ENABLE_IF(!std::is_same<Char, char>::value)>
+inline void vprint_mojibake(std::FILE*, basic_string_view<Char>, const Args&) {}
 
-  named_arg(basic_string_view<Char> name, const T& val)
-      : named_arg_base<Char>(name), value(val) {}
-};
-
-template <typename..., typename S, FMT_ENABLE_IF(!is_compile_string<S>::value)>
-inline void check_format_string(const S&) {
-#if defined(FMT_ENFORCE_COMPILE_STRING)
-  static_assert(is_compile_string<S>::value,
-                "FMT_ENFORCE_COMPILE_STRING requires all format strings to "
-                "utilize FMT_STRING() or fmt().");
+FMT_API void vprint_mojibake(std::FILE*, string_view, format_args);
+#ifndef _WIN32
+inline void vprint_mojibake(std::FILE*, string_view, format_args) {}
 #endif
-}
-template <typename..., typename S, FMT_ENABLE_IF(is_compile_string<S>::value)>
-void check_format_string(S);
+}  // namespace detail
 
-struct view {};
-template <bool...> struct bool_pack;
-template <bool... Args>
-using all_true =
-    std::is_same<bool_pack<Args..., true>, bool_pack<true, Args...>>;
-
-template <typename... Args, typename S, typename Char = char_t<S>>
-inline format_arg_store<buffer_context<Char>, remove_reference_t<Args>...>
-make_args_checked(const S& format_str,
-                  const remove_reference_t<Args>&... args) {
-  static_assert(all_true<(!std::is_base_of<view, remove_reference_t<Args>>() ||
-                          !std::is_reference<Args>())...>::value,
-                "passing views as lvalues is disallowed");
-  check_format_string<remove_const_t<remove_reference_t<Args>>...>(format_str);
-  return {args...};
+/** Formats a string and writes the output to ``out``. */
+// GCC 8 and earlier cannot handle std::back_insert_iterator<Container> with
+// vformat_to<ArgFormatter>(...) overload, so SFINAE on iterator type instead.
+template <typename OutputIt, typename S, typename Char = char_t<S>,
+          FMT_ENABLE_IF(detail::is_output_iterator<OutputIt, Char>::value)>
+OutputIt vformat_to(
+    OutputIt out, const S& format_str,
+    basic_format_args<buffer_context<type_identity_t<Char>>> args) {
+  decltype(detail::get_buffer<Char>(out)) buf(detail::get_buffer_init(out));
+  detail::vformat_to(buf, to_string_view(format_str), args);
+  return detail::get_iterator(buf);
 }
 
-template <typename Char>
-std::basic_string<Char> vformat(basic_string_view<Char> format_str,
-                                basic_format_args<buffer_context<Char>> args);
-
-template <typename Char>
-typename buffer_context<Char>::iterator vformat_to(
-    buffer<Char>& buf, basic_string_view<Char> format_str,
-    basic_format_args<buffer_context<Char>> args);
-}  // namespace internal
-
 /**
-  \rst
-  Returns a named argument to be used in a formatting function.
+ \rst
+ Formats arguments, writes the result to the output iterator ``out`` and returns
+ the iterator past the end of the output range.
 
-  The named argument holds a reference and does not extend the lifetime
-  of its arguments.
-  Consequently, a dangling reference can accidentally be created.
-  The user should take care to only pass this function temporaries when
-  the named argument is itself a temporary, as per the following example.
+ **Example**::
 
-  **Example**::
-
-    fmt::print("Elapsed time: {s:.2f} seconds", fmt::arg("s", 1.23));
-  \endrst
+   std::vector<char> out;
+   fmt::format_to(std::back_inserter(out), "{}", 42);
+ \endrst
  */
-template <typename S, typename T, typename Char = char_t<S>>
-inline internal::named_arg<T, Char> arg(const S& name, const T& arg) {
-  static_assert(internal::is_string<S>::value, "");
-  return {name, arg};
+// We cannot use FMT_ENABLE_IF because of a bug in gcc 8.3.
+template <typename OutputIt, typename S, typename... Args,
+          bool enable = detail::is_output_iterator<OutputIt, char_t<S>>::value>
+inline auto format_to(OutputIt out, const S& format_str, Args&&... args) ->
+    typename std::enable_if<enable, OutputIt>::type {
+  const auto& vargs = fmt::make_args_checked<Args...>(format_str, args...);
+  return vformat_to(out, to_string_view(format_str), vargs);
 }
 
-// Disable nested named arguments, e.g. ``arg("a", arg("b", 42))``.
-template <typename S, typename T, typename Char>
-void arg(S, internal::named_arg<T, Char>) = delete;
+template <typename OutputIt> struct format_to_n_result {
+  /** Iterator past the end of the output range. */
+  OutputIt out;
+  /** Total (not truncated) output size. */
+  size_t size;
+};
+
+template <typename OutputIt, typename Char, typename... Args,
+          FMT_ENABLE_IF(detail::is_output_iterator<OutputIt, Char>::value)>
+inline format_to_n_result<OutputIt> vformat_to_n(
+    OutputIt out, size_t n, basic_string_view<Char> format_str,
+    basic_format_args<buffer_context<type_identity_t<Char>>> args) {
+  detail::iterator_buffer<OutputIt, Char, detail::fixed_buffer_traits> buf(out,
+                                                                           n);
+  detail::vformat_to(buf, format_str, args);
+  return {buf.out(), buf.count()};
+}
 
-/** Formats a string and writes the output to ``out``. */
-// GCC 8 and earlier cannot handle std::back_insert_iterator<Container> with
-// vformat_to<ArgFormatter>(...) overload, so SFINAE on iterator type instead.
-template <typename OutputIt, typename S, typename Char = char_t<S>,
-          FMT_ENABLE_IF(
-              internal::is_contiguous_back_insert_iterator<OutputIt>::value)>
-OutputIt vformat_to(OutputIt out, const S& format_str,
-                    basic_format_args<buffer_context<Char>> args) {
-  using container = remove_reference_t<decltype(internal::get_container(out))>;
-  internal::container_buffer<container> buf((internal::get_container(out)));
-  internal::vformat_to(buf, to_string_view(format_str), args);
-  return out;
+/**
+ \rst
+ Formats arguments, writes up to ``n`` characters of the result to the output
+ iterator ``out`` and returns the total output size and the iterator past the
+ end of the output range.
+ \endrst
+ */
+template <typename OutputIt, typename S, typename... Args,
+          FMT_ENABLE_IF(detail::is_output_iterator<OutputIt, char_t<S>>::value)>
+inline format_to_n_result<OutputIt> format_to_n(OutputIt out, size_t n,
+                                                const S& format_str,
+                                                const Args&... args) {
+  const auto& vargs = fmt::make_args_checked<Args...>(format_str, args...);
+  return vformat_to_n(out, n, to_string_view(format_str), vargs);
 }
 
-template <typename Container, typename S, typename... Args,
-          FMT_ENABLE_IF(
-              is_contiguous<Container>::value&& internal::is_string<S>::value)>
-inline std::back_insert_iterator<Container> format_to(
-    std::back_insert_iterator<Container> out, const S& format_str,
-    Args&&... args) {
-  return vformat_to(
-      out, to_string_view(format_str),
-      {internal::make_args_checked<Args...>(format_str, args...)});
+/**
+  Returns the number of characters in the output of
+  ``format(format_str, args...)``.
+ */
+template <typename... Args>
+inline size_t formatted_size(string_view format_str, Args&&... args) {
+  const auto& vargs = fmt::make_args_checked<Args...>(format_str, args...);
+  detail::counting_buffer<> buf;
+  detail::vformat_to(buf, format_str, vargs);
+  return buf.count();
 }
 
 template <typename S, typename Char = char_t<S>>
-inline std::basic_string<Char> vformat(
-    const S& format_str, basic_format_args<buffer_context<Char>> args) {
-  return internal::vformat(to_string_view(format_str), args);
+FMT_INLINE std::basic_string<Char> vformat(
+    const S& format_str,
+    basic_format_args<buffer_context<type_identity_t<Char>>> args) {
+  return detail::vformat(to_string_view(format_str), args);
 }
 
 /**
@@ -1472,47 +2063,51 @@ inline std::basic_string<Char> vformat(
 // Pass char_t as a default template parameter instead of using
 // std::basic_string<char_t<S>> to reduce the symbol size.
 template <typename S, typename... Args, typename Char = char_t<S>>
-inline std::basic_string<Char> format(const S& format_str, Args&&... args) {
-  return internal::vformat(
-      to_string_view(format_str),
-      {internal::make_args_checked<Args...>(format_str, args...)});
+FMT_INLINE std::basic_string<Char> format(const S& format_str, Args&&... args) {
+  const auto& vargs = fmt::make_args_checked<Args...>(format_str, args...);
+  return detail::vformat(to_string_view(format_str), vargs);
 }
 
-FMT_API void vprint(std::FILE* f, string_view format_str, format_args args);
-FMT_API void vprint(string_view format_str, format_args args);
+FMT_API void vprint(string_view, format_args);
+FMT_API void vprint(std::FILE*, string_view, format_args);
 
 /**
   \rst
-  Prints formatted data to the file *f*. For wide format strings,
-  *f* should be in wide-oriented mode set via ``fwide(f, 1)`` or
-  ``_setmode(_fileno(f), _O_U8TEXT)`` on Windows.
+  Formats ``args`` according to specifications in ``format_str`` and writes the
+  output to the file ``f``. Strings are assumed to be Unicode-encoded unless the
+  ``FMT_UNICODE`` macro is set to 0.
 
   **Example**::
 
     fmt::print(stderr, "Don't {}!", "panic");
   \endrst
  */
-template <typename S, typename... Args,
-          FMT_ENABLE_IF(internal::is_string<S>::value)>
+template <typename S, typename... Args, typename Char = char_t<S>>
 inline void print(std::FILE* f, const S& format_str, Args&&... args) {
-  vprint(f, to_string_view(format_str),
-         internal::make_args_checked<Args...>(format_str, args...));
+  const auto& vargs = fmt::make_args_checked<Args...>(format_str, args...);
+  return detail::is_unicode<Char>()
+             ? vprint(f, to_string_view(format_str), vargs)
+             : detail::vprint_mojibake(f, to_string_view(format_str), vargs);
 }
 
 /**
   \rst
-  Prints formatted data to ``stdout``.
+  Formats ``args`` according to specifications in ``format_str`` and writes
+  the output to ``stdout``. Strings are assumed to be Unicode-encoded unless
+  the ``FMT_UNICODE`` macro is set to 0.
 
   **Example**::
 
     fmt::print("Elapsed time: {0:.2f} seconds", 1.23);
   \endrst
  */
-template <typename S, typename... Args,
-          FMT_ENABLE_IF(internal::is_string<S>::value)>
+template <typename S, typename... Args, typename Char = char_t<S>>
 inline void print(const S& format_str, Args&&... args) {
-  vprint(to_string_view(format_str),
-         internal::make_args_checked<Args...>(format_str, args...));
+  const auto& vargs = fmt::make_args_checked<Args...>(format_str, args...);
+  return detail::is_unicode<Char>()
+             ? vprint(to_string_view(format_str), vargs)
+             : detail::vprint_mojibake(stdout, to_string_view(format_str),
+                                       vargs);
 }
 FMT_END_NAMESPACE
 
diff --git a/Externals/fmt/include/fmt/format-inl.h b/Externals/fmt/include/fmt/format-inl.h
index 72b304665df9..b7cb3209c855 100755
--- a/Externals/fmt/include/fmt/format-inl.h
+++ b/Externals/fmt/include/fmt/format-inl.h
@@ -8,56 +8,40 @@
 #ifndef FMT_FORMAT_INL_H_
 #define FMT_FORMAT_INL_H_
 
-#include "format.h"
-
 #include <cassert>
 #include <cctype>
 #include <climits>
 #include <cmath>
 #include <cstdarg>
-#include <cstring>  // for std::memmove
+#include <cstring>  // std::memmove
 #include <cwchar>
-#if !defined(FMT_STATIC_THOUSANDS_SEPARATOR)
-#  include <locale>
-#endif
+#include <exception>
 
-#if FMT_USE_WINDOWS_H
-#  if !defined(FMT_HEADER_ONLY) && !defined(WIN32_LEAN_AND_MEAN)
-#    define WIN32_LEAN_AND_MEAN
-#  endif
-#  if defined(NOMINMAX) || defined(FMT_WIN_MINMAX)
-#    include <windows.h>
-#  else
-#    define NOMINMAX
-#    include <windows.h>
-#    undef NOMINMAX
-#  endif
+#ifndef FMT_STATIC_THOUSANDS_SEPARATOR
+#  include <locale>
 #endif
 
-#if FMT_EXCEPTIONS
-#  define FMT_TRY try
-#  define FMT_CATCH(x) catch (x)
-#else
-#  define FMT_TRY if (true)
-#  define FMT_CATCH(x) if (false)
+#ifdef _WIN32
+#  include <io.h>  // _isatty
 #endif
 
-#ifdef _MSC_VER
-#  pragma warning(push)
-#  pragma warning(disable : 4702)  // unreachable code
-#endif
+#include "format.h"
 
 // Dummy implementations of strerror_r and strerror_s called if corresponding
 // system functions are not available.
-inline fmt::internal::null<> strerror_r(int, char*, ...) { return {}; }
-inline fmt::internal::null<> strerror_s(char*, std::size_t, ...) { return {}; }
+inline fmt::detail::null<> strerror_r(int, char*, ...) { return {}; }
+inline fmt::detail::null<> strerror_s(char*, size_t, ...) { return {}; }
 
 FMT_BEGIN_NAMESPACE
-namespace internal {
+namespace detail {
 
 FMT_FUNC void assert_fail(const char* file, int line, const char* message) {
-  print(stderr, "{}:{}: assertion failed: {}", file, line, message);
-  std::abort();
+  // Use unchecked std::fprintf to avoid triggering another assertion when
+  // writing to stderr fails
+  std::fprintf(stderr, "%s:%d: assertion failed: %s", file, line, message);
+  // Chosen instead of std::abort to satisfy Clang in CUDA mode during device
+  // code pass.
+  std::terminate();
 }
 
 #ifndef _MSC_VER
@@ -73,8 +57,6 @@ inline int fmt_snprintf(char* buffer, size_t size, const char* format, ...) {
 #  define FMT_SNPRINTF fmt_snprintf
 #endif  // _MSC_VER
 
-using format_func = void (*)(internal::buffer<char>&, int, string_view);
-
 // A portable thread-safe version of strerror.
 // Sets buffer to point to a string describing the error code.
 // This can be either a pointer to a string stored in buffer,
@@ -84,15 +66,15 @@ using format_func = void (*)(internal::buffer<char>&, int, string_view);
 //   ERANGE - buffer is not large enough to store the error message
 //   other  - failure
 // Buffer should be at least of size 1.
-FMT_FUNC int safe_strerror(int error_code, char*& buffer,
-                           std::size_t buffer_size) FMT_NOEXCEPT {
+inline int safe_strerror(int error_code, char*& buffer,
+                         size_t buffer_size) FMT_NOEXCEPT {
   FMT_ASSERT(buffer != nullptr && buffer_size != 0, "invalid buffer");
 
   class dispatcher {
    private:
     int error_code_;
     char*& buffer_;
-    std::size_t buffer_size_;
+    size_t buffer_size_;
 
     // A noop assignment operator to avoid bogus warnings.
     void operator=(const dispatcher&) {}
@@ -104,6 +86,7 @@ FMT_FUNC int safe_strerror(int error_code, char*& buffer,
     }
 
     // Handle the result of GNU-specific version of strerror_r.
+    FMT_MAYBE_UNUSED
     int handle(char* message) {
       // If the buffer is full then the message is probably truncated.
       if (message == buffer_ && strlen(buffer_) == buffer_size_ - 1)
@@ -113,11 +96,13 @@ FMT_FUNC int safe_strerror(int error_code, char*& buffer,
     }
 
     // Handle the case when strerror_r is not available.
-    int handle(internal::null<>) {
+    FMT_MAYBE_UNUSED
+    int handle(detail::null<>) {
       return fallback(strerror_s(buffer_, buffer_size_, error_code_));
     }
 
     // Fallback to strerror_s when strerror_r is not available.
+    FMT_MAYBE_UNUSED
     int fallback(int result) {
       // If the buffer is full then the message is probably truncated.
       return result == 0 && strlen(buffer_) == buffer_size_ - 1 ? ERANGE
@@ -126,7 +111,7 @@ FMT_FUNC int safe_strerror(int error_code, char*& buffer,
 
 #if !FMT_MSC_VER
     // Fallback to strerror if strerror_r and strerror_s are not available.
-    int fallback(internal::null<>) {
+    int fallback(detail::null<>) {
       errno = 0;
       buffer_ = strerror(error_code_);
       return errno;
@@ -134,7 +119,7 @@ FMT_FUNC int safe_strerror(int error_code, char*& buffer,
 #endif
 
    public:
-    dispatcher(int err_code, char*& buf, std::size_t buf_size)
+    dispatcher(int err_code, char*& buf, size_t buf_size)
         : error_code_(err_code), buffer_(buf), buffer_size_(buf_size) {}
 
     int run() { return handle(strerror_r(error_code_, buffer_, buffer_size_)); }
@@ -142,41 +127,29 @@ FMT_FUNC int safe_strerror(int error_code, char*& buffer,
   return dispatcher(error_code, buffer, buffer_size).run();
 }
 
-FMT_FUNC void format_error_code(internal::buffer<char>& out, int error_code,
+FMT_FUNC void format_error_code(detail::buffer<char>& out, int error_code,
                                 string_view message) FMT_NOEXCEPT {
   // Report error code making sure that the output fits into
   // inline_buffer_size to avoid dynamic memory allocation and potential
   // bad_alloc.
-  out.resize(0);
+  out.try_resize(0);
   static const char SEP[] = ": ";
   static const char ERROR_STR[] = "error ";
   // Subtract 2 to account for terminating null characters in SEP and ERROR_STR.
-  std::size_t error_code_size = sizeof(SEP) + sizeof(ERROR_STR) - 2;
+  size_t error_code_size = sizeof(SEP) + sizeof(ERROR_STR) - 2;
   auto abs_value = static_cast<uint32_or_64_or_128_t<int>>(error_code);
-  if (internal::is_negative(error_code)) {
+  if (detail::is_negative(error_code)) {
     abs_value = 0 - abs_value;
     ++error_code_size;
   }
-  error_code_size += internal::to_unsigned(internal::count_digits(abs_value));
-  internal::writer w(out);
-  if (message.size() <= inline_buffer_size - error_code_size) {
-    w.write(message);
-    w.write(SEP);
-  }
-  w.write(ERROR_STR);
-  w.write(error_code);
+  error_code_size += detail::to_unsigned(detail::count_digits(abs_value));
+  auto it = buffer_appender<char>(out);
+  if (message.size() <= inline_buffer_size - error_code_size)
+    format_to(it, "{}{}", message, SEP);
+  format_to(it, "{}{}", ERROR_STR, error_code);
   assert(out.size() <= inline_buffer_size);
 }
 
-// A wrapper around fwrite that throws on error.
-FMT_FUNC void fwrite_fully(const void* ptr, size_t size, size_t count,
-                           FILE* stream) {
-  size_t written = std::fwrite(ptr, size, count, stream);
-  if (written < count) {
-    FMT_THROW(system_error(errno, "cannot write to file"));
-  }
-}
-
 FMT_FUNC void report_error(format_func func, int error_code,
                            string_view message) FMT_NOEXCEPT {
   memory_buffer full_message;
@@ -185,10 +158,17 @@ FMT_FUNC void report_error(format_func func, int error_code,
   (void)std::fwrite(full_message.data(), full_message.size(), 1, stderr);
   std::fputc('\n', stderr);
 }
-}  // namespace internal
+
+// A wrapper around fwrite that throws on error.
+inline void fwrite_fully(const void* ptr, size_t size, size_t count,
+                         FILE* stream) {
+  size_t written = std::fwrite(ptr, size, count, stream);
+  if (written < count) FMT_THROW(system_error(errno, "cannot write to file"));
+}
+}  // namespace detail
 
 #if !defined(FMT_STATIC_THOUSANDS_SEPARATOR)
-namespace internal {
+namespace detail {
 
 template <typename Locale>
 locale_ref::locale_ref(const Locale& loc) : locale_(&loc) {
@@ -211,18 +191,16 @@ template <typename Char> FMT_FUNC Char decimal_point_impl(locale_ref loc) {
   return std::use_facet<std::numpunct<Char>>(loc.get<std::locale>())
       .decimal_point();
 }
-}  // namespace internal
+}  // namespace detail
 #else
 template <typename Char>
-FMT_FUNC std::string internal::grouping_impl(locale_ref) {
+FMT_FUNC std::string detail::grouping_impl(locale_ref) {
   return "\03";
 }
-template <typename Char>
-FMT_FUNC Char internal::thousands_sep_impl(locale_ref) {
+template <typename Char> FMT_FUNC Char detail::thousands_sep_impl(locale_ref) {
   return FMT_STATIC_THOUSANDS_SEPARATOR;
 }
-template <typename Char>
-FMT_FUNC Char internal::decimal_point_impl(locale_ref) {
+template <typename Char> FMT_FUNC Char detail::decimal_point_impl(locale_ref) {
   return '.';
 }
 #endif
@@ -239,9 +217,9 @@ FMT_FUNC void system_error::init(int err_code, string_view format_str,
   base = std::runtime_error(to_string(buffer));
 }
 
-namespace internal {
+namespace detail {
 
-template <> FMT_FUNC int count_digits<4>(internal::fallback_uintptr n) {
+template <> FMT_FUNC int count_digits<4>(detail::fallback_uintptr n) {
   // fallback_uintptr is always stored in little endian.
   int i = static_cast<int>(sizeof(void*)) - 1;
   while (i > 0 && n.value[i] == 0) --i;
@@ -250,12 +228,24 @@ template <> FMT_FUNC int count_digits<4>(internal::fallback_uintptr n) {
 }
 
 template <typename T>
-const char basic_data<T>::digits[] =
-    "0001020304050607080910111213141516171819"
-    "2021222324252627282930313233343536373839"
-    "4041424344454647484950515253545556575859"
-    "6061626364656667686970717273747576777879"
-    "8081828384858687888990919293949596979899";
+const typename basic_data<T>::digit_pair basic_data<T>::digits[] = {
+    {'0', '0'}, {'0', '1'}, {'0', '2'}, {'0', '3'}, {'0', '4'}, {'0', '5'},
+    {'0', '6'}, {'0', '7'}, {'0', '8'}, {'0', '9'}, {'1', '0'}, {'1', '1'},
+    {'1', '2'}, {'1', '3'}, {'1', '4'}, {'1', '5'}, {'1', '6'}, {'1', '7'},
+    {'1', '8'}, {'1', '9'}, {'2', '0'}, {'2', '1'}, {'2', '2'}, {'2', '3'},
+    {'2', '4'}, {'2', '5'}, {'2', '6'}, {'2', '7'}, {'2', '8'}, {'2', '9'},
+    {'3', '0'}, {'3', '1'}, {'3', '2'}, {'3', '3'}, {'3', '4'}, {'3', '5'},
+    {'3', '6'}, {'3', '7'}, {'3', '8'}, {'3', '9'}, {'4', '0'}, {'4', '1'},
+    {'4', '2'}, {'4', '3'}, {'4', '4'}, {'4', '5'}, {'4', '6'}, {'4', '7'},
+    {'4', '8'}, {'4', '9'}, {'5', '0'}, {'5', '1'}, {'5', '2'}, {'5', '3'},
+    {'5', '4'}, {'5', '5'}, {'5', '6'}, {'5', '7'}, {'5', '8'}, {'5', '9'},
+    {'6', '0'}, {'6', '1'}, {'6', '2'}, {'6', '3'}, {'6', '4'}, {'6', '5'},
+    {'6', '6'}, {'6', '7'}, {'6', '8'}, {'6', '9'}, {'7', '0'}, {'7', '1'},
+    {'7', '2'}, {'7', '3'}, {'7', '4'}, {'7', '5'}, {'7', '6'}, {'7', '7'},
+    {'7', '8'}, {'7', '9'}, {'8', '0'}, {'8', '1'}, {'8', '2'}, {'8', '3'},
+    {'8', '4'}, {'8', '5'}, {'8', '6'}, {'8', '7'}, {'8', '8'}, {'8', '9'},
+    {'9', '0'}, {'9', '1'}, {'9', '2'}, {'9', '3'}, {'9', '4'}, {'9', '5'},
+    {'9', '6'}, {'9', '7'}, {'9', '8'}, {'9', '9'}};
 
 template <typename T>
 const char basic_data<T>::hex_digits[] = "0123456789abcdef";
@@ -271,18 +261,18 @@ const uint64_t basic_data<T>::powers_of_10_64[] = {
     10000000000000000000ULL};
 
 template <typename T>
-const uint32_t basic_data<T>::zero_or_powers_of_10_32[] = {0,
+const uint32_t basic_data<T>::zero_or_powers_of_10_32[] = {0, 0,
                                                            FMT_POWERS_OF_10(1)};
 
 template <typename T>
 const uint64_t basic_data<T>::zero_or_powers_of_10_64[] = {
-    0, FMT_POWERS_OF_10(1), FMT_POWERS_OF_10(1000000000ULL),
+    0, 0, FMT_POWERS_OF_10(1), FMT_POWERS_OF_10(1000000000ULL),
     10000000000000000000ULL};
 
 // Normalized 64-bit significands of pow(10, k), for k = -348, -340, ..., 340.
 // These are generated by support/compute-powers.py.
 template <typename T>
-const uint64_t basic_data<T>::pow10_significands[] = {
+const uint64_t basic_data<T>::grisu_pow10_significands[] = {
     0xfa8fd5a0081c0288, 0xbaaee17fa23ebf76, 0x8b16fb203055ac76,
     0xcf42894a5dce35ea, 0x9a6bb0aa55653b2d, 0xe61acf033d1a45df,
     0xab70fe17c79ac6ca, 0xff77b1fcbebcdc4f, 0xbe5691ef416bd60c,
@@ -317,7 +307,7 @@ const uint64_t basic_data<T>::pow10_significands[] = {
 // Binary exponents of pow(10, k), for k = -348, -340, ..., 340, corresponding
 // to significands above.
 template <typename T>
-const int16_t basic_data<T>::pow10_exponents[] = {
+const int16_t basic_data<T>::grisu_pow10_exponents[] = {
     -1220, -1193, -1166, -1140, -1113, -1087, -1060, -1034, -1007, -980, -954,
     -927,  -901,  -874,  -847,  -821,  -794,  -768,  -741,  -715,  -688, -661,
     -635,  -608,  -582,  -555,  -529,  -502,  -475,  -449,  -422,  -396, -369,
@@ -327,6 +317,744 @@ const int16_t basic_data<T>::pow10_exponents[] = {
     534,   561,   588,   614,   641,   667,   694,   720,   747,   774,  800,
     827,   853,   880,   907,   933,   960,   986,   1013,  1039,  1066};
 
+template <typename T>
+const divtest_table_entry<uint32_t> basic_data<T>::divtest_table_for_pow5_32[] =
+    {{0x00000001, 0xffffffff}, {0xcccccccd, 0x33333333},
+     {0xc28f5c29, 0x0a3d70a3}, {0x26e978d5, 0x020c49ba},
+     {0x3afb7e91, 0x0068db8b}, {0x0bcbe61d, 0x0014f8b5},
+     {0x68c26139, 0x000431bd}, {0xae8d46a5, 0x0000d6bf},
+     {0x22e90e21, 0x00002af3}, {0x3a2e9c6d, 0x00000897},
+     {0x3ed61f49, 0x000001b7}};
+
+template <typename T>
+const divtest_table_entry<uint64_t> basic_data<T>::divtest_table_for_pow5_64[] =
+    {{0x0000000000000001, 0xffffffffffffffff},
+     {0xcccccccccccccccd, 0x3333333333333333},
+     {0x8f5c28f5c28f5c29, 0x0a3d70a3d70a3d70},
+     {0x1cac083126e978d5, 0x020c49ba5e353f7c},
+     {0xd288ce703afb7e91, 0x0068db8bac710cb2},
+     {0x5d4e8fb00bcbe61d, 0x0014f8b588e368f0},
+     {0x790fb65668c26139, 0x000431bde82d7b63},
+     {0xe5032477ae8d46a5, 0x0000d6bf94d5e57a},
+     {0xc767074b22e90e21, 0x00002af31dc46118},
+     {0x8e47ce423a2e9c6d, 0x0000089705f4136b},
+     {0x4fa7f60d3ed61f49, 0x000001b7cdfd9d7b},
+     {0x0fee64690c913975, 0x00000057f5ff85e5},
+     {0x3662e0e1cf503eb1, 0x000000119799812d},
+     {0xa47a2cf9f6433fbd, 0x0000000384b84d09},
+     {0x54186f653140a659, 0x00000000b424dc35},
+     {0x7738164770402145, 0x0000000024075f3d},
+     {0xe4a4d1417cd9a041, 0x000000000734aca5},
+     {0xc75429d9e5c5200d, 0x000000000170ef54},
+     {0xc1773b91fac10669, 0x000000000049c977},
+     {0x26b172506559ce15, 0x00000000000ec1e4},
+     {0xd489e3a9addec2d1, 0x000000000002f394},
+     {0x90e860bb892c8d5d, 0x000000000000971d},
+     {0x502e79bf1b6f4f79, 0x0000000000001e39},
+     {0xdcd618596be30fe5, 0x000000000000060b}};
+
+template <typename T>
+const uint64_t basic_data<T>::dragonbox_pow10_significands_64[] = {
+    0x81ceb32c4b43fcf5, 0xa2425ff75e14fc32, 0xcad2f7f5359a3b3f,
+    0xfd87b5f28300ca0e, 0x9e74d1b791e07e49, 0xc612062576589ddb,
+    0xf79687aed3eec552, 0x9abe14cd44753b53, 0xc16d9a0095928a28,
+    0xf1c90080baf72cb2, 0x971da05074da7bef, 0xbce5086492111aeb,
+    0xec1e4a7db69561a6, 0x9392ee8e921d5d08, 0xb877aa3236a4b44a,
+    0xe69594bec44de15c, 0x901d7cf73ab0acda, 0xb424dc35095cd810,
+    0xe12e13424bb40e14, 0x8cbccc096f5088cc, 0xafebff0bcb24aaff,
+    0xdbe6fecebdedd5bf, 0x89705f4136b4a598, 0xabcc77118461cefd,
+    0xd6bf94d5e57a42bd, 0x8637bd05af6c69b6, 0xa7c5ac471b478424,
+    0xd1b71758e219652c, 0x83126e978d4fdf3c, 0xa3d70a3d70a3d70b,
+    0xcccccccccccccccd, 0x8000000000000000, 0xa000000000000000,
+    0xc800000000000000, 0xfa00000000000000, 0x9c40000000000000,
+    0xc350000000000000, 0xf424000000000000, 0x9896800000000000,
+    0xbebc200000000000, 0xee6b280000000000, 0x9502f90000000000,
+    0xba43b74000000000, 0xe8d4a51000000000, 0x9184e72a00000000,
+    0xb5e620f480000000, 0xe35fa931a0000000, 0x8e1bc9bf04000000,
+    0xb1a2bc2ec5000000, 0xde0b6b3a76400000, 0x8ac7230489e80000,
+    0xad78ebc5ac620000, 0xd8d726b7177a8000, 0x878678326eac9000,
+    0xa968163f0a57b400, 0xd3c21bcecceda100, 0x84595161401484a0,
+    0xa56fa5b99019a5c8, 0xcecb8f27f4200f3a, 0x813f3978f8940984,
+    0xa18f07d736b90be5, 0xc9f2c9cd04674ede, 0xfc6f7c4045812296,
+    0x9dc5ada82b70b59d, 0xc5371912364ce305, 0xf684df56c3e01bc6,
+    0x9a130b963a6c115c, 0xc097ce7bc90715b3, 0xf0bdc21abb48db20,
+    0x96769950b50d88f4, 0xbc143fa4e250eb31, 0xeb194f8e1ae525fd,
+    0x92efd1b8d0cf37be, 0xb7abc627050305ad, 0xe596b7b0c643c719,
+    0x8f7e32ce7bea5c6f, 0xb35dbf821ae4f38b, 0xe0352f62a19e306e};
+
+template <typename T>
+const uint128_wrapper basic_data<T>::dragonbox_pow10_significands_128[] = {
+#if FMT_USE_FULL_CACHE_DRAGONBOX
+    {0xff77b1fcbebcdc4f, 0x25e8e89c13bb0f7b},
+    {0x9faacf3df73609b1, 0x77b191618c54e9ad},
+    {0xc795830d75038c1d, 0xd59df5b9ef6a2418},
+    {0xf97ae3d0d2446f25, 0x4b0573286b44ad1e},
+    {0x9becce62836ac577, 0x4ee367f9430aec33},
+    {0xc2e801fb244576d5, 0x229c41f793cda740},
+    {0xf3a20279ed56d48a, 0x6b43527578c11110},
+    {0x9845418c345644d6, 0x830a13896b78aaaa},
+    {0xbe5691ef416bd60c, 0x23cc986bc656d554},
+    {0xedec366b11c6cb8f, 0x2cbfbe86b7ec8aa9},
+    {0x94b3a202eb1c3f39, 0x7bf7d71432f3d6aa},
+    {0xb9e08a83a5e34f07, 0xdaf5ccd93fb0cc54},
+    {0xe858ad248f5c22c9, 0xd1b3400f8f9cff69},
+    {0x91376c36d99995be, 0x23100809b9c21fa2},
+    {0xb58547448ffffb2d, 0xabd40a0c2832a78b},
+    {0xe2e69915b3fff9f9, 0x16c90c8f323f516d},
+    {0x8dd01fad907ffc3b, 0xae3da7d97f6792e4},
+    {0xb1442798f49ffb4a, 0x99cd11cfdf41779d},
+    {0xdd95317f31c7fa1d, 0x40405643d711d584},
+    {0x8a7d3eef7f1cfc52, 0x482835ea666b2573},
+    {0xad1c8eab5ee43b66, 0xda3243650005eed0},
+    {0xd863b256369d4a40, 0x90bed43e40076a83},
+    {0x873e4f75e2224e68, 0x5a7744a6e804a292},
+    {0xa90de3535aaae202, 0x711515d0a205cb37},
+    {0xd3515c2831559a83, 0x0d5a5b44ca873e04},
+    {0x8412d9991ed58091, 0xe858790afe9486c3},
+    {0xa5178fff668ae0b6, 0x626e974dbe39a873},
+    {0xce5d73ff402d98e3, 0xfb0a3d212dc81290},
+    {0x80fa687f881c7f8e, 0x7ce66634bc9d0b9a},
+    {0xa139029f6a239f72, 0x1c1fffc1ebc44e81},
+    {0xc987434744ac874e, 0xa327ffb266b56221},
+    {0xfbe9141915d7a922, 0x4bf1ff9f0062baa9},
+    {0x9d71ac8fada6c9b5, 0x6f773fc3603db4aa},
+    {0xc4ce17b399107c22, 0xcb550fb4384d21d4},
+    {0xf6019da07f549b2b, 0x7e2a53a146606a49},
+    {0x99c102844f94e0fb, 0x2eda7444cbfc426e},
+    {0xc0314325637a1939, 0xfa911155fefb5309},
+    {0xf03d93eebc589f88, 0x793555ab7eba27cb},
+    {0x96267c7535b763b5, 0x4bc1558b2f3458df},
+    {0xbbb01b9283253ca2, 0x9eb1aaedfb016f17},
+    {0xea9c227723ee8bcb, 0x465e15a979c1cadd},
+    {0x92a1958a7675175f, 0x0bfacd89ec191eca},
+    {0xb749faed14125d36, 0xcef980ec671f667c},
+    {0xe51c79a85916f484, 0x82b7e12780e7401b},
+    {0x8f31cc0937ae58d2, 0xd1b2ecb8b0908811},
+    {0xb2fe3f0b8599ef07, 0x861fa7e6dcb4aa16},
+    {0xdfbdcece67006ac9, 0x67a791e093e1d49b},
+    {0x8bd6a141006042bd, 0xe0c8bb2c5c6d24e1},
+    {0xaecc49914078536d, 0x58fae9f773886e19},
+    {0xda7f5bf590966848, 0xaf39a475506a899f},
+    {0x888f99797a5e012d, 0x6d8406c952429604},
+    {0xaab37fd7d8f58178, 0xc8e5087ba6d33b84},
+    {0xd5605fcdcf32e1d6, 0xfb1e4a9a90880a65},
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+    {0xa5c7ea73224deff3, 0x12b9b522906c0800},
+    {0xcf39e50feae16bef, 0xd768226b34870a00},
+    {0x81842f29f2cce375, 0xe6a1158300d46640},
+    {0xa1e53af46f801c53, 0x60495ae3c1097fd0},
+    {0xca5e89b18b602368, 0x385bb19cb14bdfc4},
+    {0xfcf62c1dee382c42, 0x46729e03dd9ed7b5},
+    {0x9e19db92b4e31ba9, 0x6c07a2c26a8346d1},
+    {0xc5a05277621be293, 0xc7098b7305241885},
+    {0xf70867153aa2db38, 0xb8cbee4fc66d1ea7}
+#else
+    {0xff77b1fcbebcdc4f, 0x25e8e89c13bb0f7b},
+    {0xce5d73ff402d98e3, 0xfb0a3d212dc81290},
+    {0xa6b34ad8c9dfc06f, 0xf42faa48c0ea481f},
+    {0x86a8d39ef77164bc, 0xae5dff9c02033198},
+    {0xd98ddaee19068c76, 0x3badd624dd9b0958},
+    {0xafbd2350644eeacf, 0xe5d1929ef90898fb},
+    {0x8df5efabc5979c8f, 0xca8d3ffa1ef463c2},
+    {0xe55990879ddcaabd, 0xcc420a6a101d0516},
+    {0xb94470938fa89bce, 0xf808e40e8d5b3e6a},
+    {0x95a8637627989aad, 0xdde7001379a44aa9},
+    {0xf1c90080baf72cb1, 0x5324c68b12dd6339},
+    {0xc350000000000000, 0x0000000000000000},
+    {0x9dc5ada82b70b59d, 0xf020000000000000},
+    {0xfee50b7025c36a08, 0x02f236d04753d5b4},
+    {0xcde6fd5e09abcf26, 0xed4c0226b55e6f86},
+    {0xa6539930bf6bff45, 0x84db8346b786151c},
+    {0x865b86925b9bc5c2, 0x0b8a2392ba45a9b2},
+    {0xd910f7ff28069da4, 0x1b2ba1518094da04},
+    {0xaf58416654a6babb, 0x387ac8d1970027b2},
+    {0x8da471a9de737e24, 0x5ceaecfed289e5d2},
+    {0xe4d5e82392a40515, 0x0fabaf3feaa5334a},
+    {0xb8da1662e7b00a17, 0x3d6a751f3b936243},
+    {0x95527a5202df0ccb, 0x0f37801e0c43ebc8}
+#endif
+};
+
+#if !FMT_USE_FULL_CACHE_DRAGONBOX
+template <typename T>
+const uint64_t basic_data<T>::powers_of_5_64[] = {
+    0x0000000000000001, 0x0000000000000005, 0x0000000000000019,
+    0x000000000000007d, 0x0000000000000271, 0x0000000000000c35,
+    0x0000000000003d09, 0x000000000001312d, 0x000000000005f5e1,
+    0x00000000001dcd65, 0x00000000009502f9, 0x0000000002e90edd,
+    0x000000000e8d4a51, 0x0000000048c27395, 0x000000016bcc41e9,
+    0x000000071afd498d, 0x0000002386f26fc1, 0x000000b1a2bc2ec5,
+    0x000003782dace9d9, 0x00001158e460913d, 0x000056bc75e2d631,
+    0x0001b1ae4d6e2ef5, 0x000878678326eac9, 0x002a5a058fc295ed,
+    0x00d3c21bcecceda1, 0x0422ca8b0a00a425, 0x14adf4b7320334b9};
+
+template <typename T>
+const uint32_t basic_data<T>::dragonbox_pow10_recovery_errors[] = {
+    0x50001400, 0x54044100, 0x54014555, 0x55954415, 0x54115555, 0x00000001,
+    0x50000000, 0x00104000, 0x54010004, 0x05004001, 0x55555544, 0x41545555,
+    0x54040551, 0x15445545, 0x51555514, 0x10000015, 0x00101100, 0x01100015,
+    0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x04450514, 0x45414110,
+    0x55555145, 0x50544050, 0x15040155, 0x11054140, 0x50111514, 0x11451454,
+    0x00400541, 0x00000000, 0x55555450, 0x10056551, 0x10054011, 0x55551014,
+    0x69514555, 0x05151109, 0x00155555};
+#endif
+
 template <typename T>
 const char basic_data<T>::foreground_color[] = "\x1b[38;2;";
 template <typename T>
@@ -334,6 +1062,10 @@ const char basic_data<T>::background_color[] = "\x1b[48;2;";
 template <typename T> const char basic_data<T>::reset_color[] = "\x1b[0m";
 template <typename T> const wchar_t basic_data<T>::wreset_color[] = L"\x1b[0m";
 template <typename T> const char basic_data<T>::signs[] = {0, '-', '+', ' '};
+template <typename T>
+const char basic_data<T>::left_padding_shifts[] = {31, 31, 0, 1, 0};
+template <typename T>
+const char basic_data<T>::right_padding_shifts[] = {0, 31, 0, 1, 0};
 
 template <typename T> struct bits {
   static FMT_CONSTEXPR_DECL const int value =
@@ -356,6 +1088,14 @@ class fp {
  private:
   using significand_type = uint64_t;
 
+  template <typename Float>
+  using is_supported_float = bool_constant<sizeof(Float) == sizeof(uint64_t) ||
+                                           sizeof(Float) == sizeof(uint32_t)>;
+
+ public:
+  significand_type f;
+  int e;
+
   // All sizes are in bits.
   // Subtract 1 to account for an implicit most significant bit in the
   // normalized form.
@@ -363,11 +1103,6 @@ class fp {
       std::numeric_limits<double>::digits - 1;
   static FMT_CONSTEXPR_DECL const uint64_t implicit_bit =
       1ULL << double_significand_size;
-
- public:
-  significand_type f;
-  int e;
-
   static FMT_CONSTEXPR_DECL const int significand_size =
       bits<significand_type>::value;
 
@@ -378,80 +1113,56 @@ class fp {
   // errors on platforms where double is not IEEE754.
   template <typename Double> explicit fp(Double d) { assign(d); }
 
-  // Normalizes the value converted from double and multiplied by (1 << SHIFT).
-  template <int SHIFT> friend fp normalize(fp value) {
-    // Handle subnormals.
-    const auto shifted_implicit_bit = fp::implicit_bit << SHIFT;
-    while ((value.f & shifted_implicit_bit) == 0) {
-      value.f <<= 1;
-      --value.e;
-    }
-    // Subtract 1 to account for hidden bit.
-    const auto offset =
-        fp::significand_size - fp::double_significand_size - SHIFT - 1;
-    value.f <<= offset;
-    value.e -= offset;
-    return value;
-  }
-
   // Assigns d to this and return true iff predecessor is closer than successor.
-  template <typename Double, FMT_ENABLE_IF(sizeof(Double) == sizeof(uint64_t))>
-  bool assign(Double d) {
-    // Assume double is in the format [sign][exponent][significand].
-    using limits = std::numeric_limits<Double>;
+  template <typename Float, FMT_ENABLE_IF(is_supported_float<Float>::value)>
+  bool assign(Float d) {
+    // Assume float is in the format [sign][exponent][significand].
+    using limits = std::numeric_limits<Float>;
+    const int float_significand_size = limits::digits - 1;
     const int exponent_size =
-        bits<Double>::value - double_significand_size - 1;  // -1 for sign
-    const uint64_t significand_mask = implicit_bit - 1;
+        bits<Float>::value - float_significand_size - 1;  // -1 for sign
+    const uint64_t float_implicit_bit = 1ULL << float_significand_size;
+    const uint64_t significand_mask = float_implicit_bit - 1;
     const uint64_t exponent_mask = (~0ULL >> 1) & ~significand_mask;
     const int exponent_bias = (1 << exponent_size) - limits::max_exponent - 1;
-    auto u = bit_cast<uint64_t>(d);
+    constexpr bool is_double = sizeof(Float) == sizeof(uint64_t);
+    auto u = bit_cast<conditional_t<is_double, uint64_t, uint32_t>>(d);
     f = u & significand_mask;
-    auto biased_e = (u & exponent_mask) >> double_significand_size;
+    int biased_e =
+        static_cast<int>((u & exponent_mask) >> float_significand_size);
     // Predecessor is closer if d is a normalized power of 2 (f == 0) other than
     // the smallest normalized number (biased_e > 1).
     bool is_predecessor_closer = f == 0 && biased_e > 1;
     if (biased_e != 0)
-      f += implicit_bit;
+      f += float_implicit_bit;
     else
       biased_e = 1;  // Subnormals use biased exponent 1 (min exponent).
-    e = static_cast<int>(biased_e - exponent_bias - double_significand_size);
+    e = biased_e - exponent_bias - float_significand_size;
     return is_predecessor_closer;
   }
 
-  template <typename Double, FMT_ENABLE_IF(sizeof(Double) != sizeof(uint64_t))>
-  bool assign(Double) {
+  template <typename Float, FMT_ENABLE_IF(!is_supported_float<Float>::value)>
+  bool assign(Float) {
     *this = fp();
     return false;
   }
+};
 
-  // Assigns d to this together with computing lower and upper boundaries,
-  // where a boundary is a value half way between the number and its predecessor
-  // (lower) or successor (upper). The upper boundary is normalized and lower
-  // has the same exponent but may be not normalized.
-  template <typename Double> boundaries assign_with_boundaries(Double d) {
-    bool is_lower_closer = assign(d);
-    fp lower =
-        is_lower_closer ? fp((f << 2) - 1, e - 2) : fp((f << 1) - 1, e - 1);
-    // 1 in normalize accounts for the exponent shift above.
-    fp upper = normalize<1>(fp((f << 1) + 1, e - 1));
-    lower.f <<= lower.e - upper.e;
-    return boundaries{lower.f, upper.f};
-  }
-
-  template <typename Double> boundaries assign_float_with_boundaries(Double d) {
-    assign(d);
-    constexpr int min_normal_e = std::numeric_limits<float>::min_exponent -
-                                 std::numeric_limits<double>::digits;
-    significand_type half_ulp = 1 << (std::numeric_limits<double>::digits -
-                                      std::numeric_limits<float>::digits - 1);
-    if (min_normal_e > e) half_ulp <<= min_normal_e - e;
-    fp upper = normalize<0>(fp(f + half_ulp, e));
-    fp lower = fp(
-        f - (half_ulp >> ((f == implicit_bit && e > min_normal_e) ? 1 : 0)), e);
-    lower.f <<= lower.e - upper.e;
-    return boundaries{lower.f, upper.f};
+// Normalizes the value converted from double and multiplied by (1 << SHIFT).
+template <int SHIFT> fp normalize(fp value) {
+  // Handle subnormals.
+  const auto shifted_implicit_bit = fp::implicit_bit << SHIFT;
+  while ((value.f & shifted_implicit_bit) == 0) {
+    value.f <<= 1;
+    --value.e;
   }
-};
+  // Subtract 1 to account for hidden bit.
+  const auto offset =
+      fp::significand_size - fp::double_significand_size - SHIFT - 1;
+  value.f <<= offset;
+  value.e -= offset;
+  return value;
+}
 
 inline bool operator==(fp x, fp y) { return x.f == y.f && x.e == y.e; }
 
@@ -477,14 +1188,13 @@ inline fp operator*(fp x, fp y) { return {multiply(x.f, y.f), x.e + y.e + 64}; }
 
 // Returns a cached power of 10 `c_k = c_k.f * pow(2, c_k.e)` such that its
 // (binary) exponent satisfies `min_exponent <= c_k.e <= min_exponent + 28`.
-FMT_FUNC fp get_cached_power(int min_exponent, int& pow10_exponent) {
-  const uint64_t one_over_log2_10 = 0x4d104d42;  // round(pow(2, 32) / log2(10))
+inline fp get_cached_power(int min_exponent, int& pow10_exponent) {
+  const int shift = 32;
+  const auto significand = static_cast<int64_t>(data::log10_2_significand);
   int index = static_cast<int>(
-      static_cast<int64_t>(
-          (min_exponent + fp::significand_size - 1) * one_over_log2_10 +
-          ((uint64_t(1) << 32) - 1)  // ceil
-          ) >>
-      32  // arithmetic shift
+      ((min_exponent + fp::significand_size - 1) * (significand >> shift) +
+       ((int64_t(1) << shift) - 1))  // ceil
+      >> 32                          // arithmetic shift
   );
   // Decimal exponent of the first (smallest) cached power of 10.
   const int first_dec_exp = -348;
@@ -492,7 +1202,8 @@ FMT_FUNC fp get_cached_power(int min_exponent, int& pow10_exponent) {
   const int dec_exp_step = 8;
   index = (index - first_dec_exp - 1) / dec_exp_step + 1;
   pow10_exponent = first_dec_exp + index * dec_exp_step;
-  return {data::pow10_significands[index], data::pow10_exponents[index]};
+  return {data::grisu_pow10_significands[index],
+          data::grisu_pow10_exponents[index]};
 }
 
 // A simple accumulator to hold the sums of terms in bigint::square if uint128_t
@@ -526,20 +1237,23 @@ class bigint {
   basic_memory_buffer<bigit, bigits_capacity> bigits_;
   int exp_;
 
+  bigit operator[](int index) const { return bigits_[to_unsigned(index)]; }
+  bigit& operator[](int index) { return bigits_[to_unsigned(index)]; }
+
   static FMT_CONSTEXPR_DECL const int bigit_bits = bits<bigit>::value;
 
   friend struct formatter<bigint>;
 
   void subtract_bigits(int index, bigit other, bigit& borrow) {
-    auto result = static_cast<double_bigit>(bigits_[index]) - other - borrow;
-    bigits_[index] = static_cast<bigit>(result);
+    auto result = static_cast<double_bigit>((*this)[index]) - other - borrow;
+    (*this)[index] = static_cast<bigit>(result);
     borrow = static_cast<bigit>(result >> (bigit_bits * 2 - 1));
   }
 
   void remove_leading_zeros() {
     int num_bigits = static_cast<int>(bigits_.size()) - 1;
-    while (num_bigits > 0 && bigits_[num_bigits] == 0) --num_bigits;
-    bigits_.resize(num_bigits + 1);
+    while (num_bigits > 0 && (*this)[num_bigits] == 0) --num_bigits;
+    bigits_.resize(to_unsigned(num_bigits + 1));
   }
 
   // Computes *this -= other assuming aligned bigints and *this >= other.
@@ -548,10 +1262,8 @@ class bigint {
     FMT_ASSERT(compare(*this, other) >= 0, "");
     bigit borrow = 0;
     int i = other.exp_ - exp_;
-    for (int j = 0, n = static_cast<int>(other.bigits_.size()); j != n;
-         ++i, ++j) {
+    for (size_t j = 0, n = other.bigits_.size(); j != n; ++i, ++j)
       subtract_bigits(i, other.bigits_[j], borrow);
-    }
     while (borrow > 0) subtract_bigits(i, 0, borrow);
     remove_leading_zeros();
   }
@@ -593,14 +1305,15 @@ class bigint {
   void operator=(const bigint&) = delete;
 
   void assign(const bigint& other) {
-    bigits_.resize(other.bigits_.size());
+    auto size = other.bigits_.size();
+    bigits_.resize(size);
     auto data = other.bigits_.data();
-    std::copy(data, data + other.bigits_.size(), bigits_.data());
+    std::copy(data, data + size, make_checked(bigits_.data(), size));
     exp_ = other.exp_;
   }
 
   void assign(uint64_t n) {
-    int num_bigits = 0;
+    size_t num_bigits = 0;
     do {
       bigits_[num_bigits++] = n & ~bigit(0);
       n >>= bigit_bits;
@@ -611,7 +1324,7 @@ class bigint {
 
   int num_bigits() const { return static_cast<int>(bigits_.size()) + exp_; }
 
-  bigint& operator<<=(int shift) {
+  FMT_NOINLINE bigint& operator<<=(int shift) {
     assert(shift >= 0);
     exp_ += shift / bigit_bits;
     shift %= bigit_bits;
@@ -641,7 +1354,7 @@ class bigint {
     int end = i - j;
     if (end < 0) end = 0;
     for (; i >= end; --i, --j) {
-      bigit lhs_bigit = lhs.bigits_[i], rhs_bigit = rhs.bigits_[j];
+      bigit lhs_bigit = lhs[i], rhs_bigit = rhs[j];
       if (lhs_bigit != rhs_bigit) return lhs_bigit > rhs_bigit ? 1 : -1;
     }
     if (i != j) return i > j ? 1 : -1;
@@ -656,7 +1369,7 @@ class bigint {
     if (max_lhs_bigits + 1 < num_rhs_bigits) return -1;
     if (max_lhs_bigits > num_rhs_bigits) return 1;
     auto get_bigit = [](const bigint& n, int i) -> bigit {
-      return i >= n.exp_ && i < n.num_bigits() ? n.bigits_[i - n.exp_] : 0;
+      return i >= n.exp_ && i < n.num_bigits() ? n[i - n.exp_] : 0;
     };
     double_bigit borrow = 0;
     int min_exp = (std::min)((std::min)(lhs1.exp_, lhs2.exp_), rhs.exp_);
@@ -696,7 +1409,7 @@ class bigint {
     basic_memory_buffer<bigit, bigits_capacity> n(std::move(bigits_));
     int num_bigits = static_cast<int>(bigits_.size());
     int num_result_bigits = 2 * num_bigits;
-    bigits_.resize(num_result_bigits);
+    bigits_.resize(to_unsigned(num_result_bigits));
     using accumulator_t = conditional_t<FMT_USE_INT128, uint128_t, accumulator>;
     auto sum = accumulator_t();
     for (int bigit_index = 0; bigit_index < num_bigits; ++bigit_index) {
@@ -706,7 +1419,7 @@ class bigint {
         // Most terms are multiplied twice which can be optimized in the future.
         sum += static_cast<double_bigit>(n[i]) * n[j];
       }
-      bigits_[bigit_index] = static_cast<bigit>(sum);
+      (*this)[bigit_index] = static_cast<bigit>(sum);
       sum >>= bits<bigit>::value;  // Compute the carry.
     }
     // Do the same for the top half.
@@ -714,7 +1427,7 @@ class bigint {
          ++bigit_index) {
       for (int j = num_bigits - 1, i = bigit_index - j; i < num_bigits;)
         sum += static_cast<double_bigit>(n[i++]) * n[j--];
-      bigits_[bigit_index] = static_cast<bigit>(sum);
+      (*this)[bigit_index] = static_cast<bigit>(sum);
       sum >>= bits<bigit>::value;
     }
     --num_result_bigits;
@@ -722,22 +1435,26 @@ class bigint {
     exp_ *= 2;
   }
 
+  // If this bigint has a bigger exponent than other, adds trailing zero to make
+  // exponents equal. This simplifies some operations such as subtraction.
+  void align(const bigint& other) {
+    int exp_difference = exp_ - other.exp_;
+    if (exp_difference <= 0) return;
+    int num_bigits = static_cast<int>(bigits_.size());
+    bigits_.resize(to_unsigned(num_bigits + exp_difference));
+    for (int i = num_bigits - 1, j = i + exp_difference; i >= 0; --i, --j)
+      bigits_[j] = bigits_[i];
+    std::uninitialized_fill_n(bigits_.data(), exp_difference, 0);
+    exp_ -= exp_difference;
+  }
+
   // Divides this bignum by divisor, assigning the remainder to this and
   // returning the quotient.
   int divmod_assign(const bigint& divisor) {
     FMT_ASSERT(this != &divisor, "");
     if (compare(*this, divisor) < 0) return 0;
-    int num_bigits = static_cast<int>(bigits_.size());
-    FMT_ASSERT(divisor.bigits_[divisor.bigits_.size() - 1] != 0, "");
-    int exp_difference = exp_ - divisor.exp_;
-    if (exp_difference > 0) {
-      // Align bigints by adding trailing zeros to simplify subtraction.
-      bigits_.resize(num_bigits + exp_difference);
-      for (int i = num_bigits - 1, j = i + exp_difference; i >= 0; --i, --j)
-        bigits_[j] = bigits_[i];
-      std::uninitialized_fill_n(bigits_.data(), exp_difference, 0);
-      exp_ -= exp_difference;
-    }
+    FMT_ASSERT(divisor.bigits_[divisor.bigits_.size() - 1u] != 0, "");
+    align(divisor);
     int quotient = 0;
     do {
       subtract_aligned(divisor);
@@ -747,7 +1464,7 @@ class bigint {
   }
 };
 
-enum round_direction { unknown, up, down };
+enum class round_direction { unknown, up, down };
 
 // Given the divisor (normally a power of 10), the remainder = v % divisor for
 // some number v and the error, returns whether v should be rounded up, down, or
@@ -760,13 +1477,13 @@ inline round_direction get_round_direction(uint64_t divisor, uint64_t remainder,
   FMT_ASSERT(error < divisor - error, "");  // error * 2 won't overflow.
   // Round down if (remainder + error) * 2 <= divisor.
   if (remainder <= divisor - remainder && error * 2 <= divisor - remainder * 2)
-    return down;
+    return round_direction::down;
   // Round up if (remainder - error) * 2 >= divisor.
   if (remainder >= error &&
       remainder - error >= divisor - (remainder - error)) {
-    return up;
+    return round_direction::up;
   }
-  return unknown;
+  return round_direction::unknown;
 }
 
 namespace digits {
@@ -842,8 +1559,7 @@ FMT_ALWAYS_INLINE digits::result grisu_gen_digits(fp value, uint64_t error,
       FMT_ASSERT(false, "invalid number of digits");
     }
     --exp;
-    uint64_t remainder =
-        (static_cast<uint64_t>(integral) << -one.e) + fractional;
+    auto remainder = (static_cast<uint64_t>(integral) << -one.e) + fractional;
     result = handler.on_digit(static_cast<char>('0' + digit),
                               data::powers_of_10_64[exp] << -one.e, remainder,
                               error, exp, true);
@@ -853,8 +1569,7 @@ FMT_ALWAYS_INLINE digits::result grisu_gen_digits(fp value, uint64_t error,
   for (;;) {
     fractional *= 10;
     error *= 10;
-    char digit =
-        static_cast<char>('0' + static_cast<char>(fractional >> -one.e));
+    char digit = static_cast<char>('0' + (fractional >> -one.e));
     fractional &= one.f - 1;
     --exp;
     result = handler.on_digit(digit, one.f, fractional, error, exp, false);
@@ -882,8 +1597,8 @@ struct fixed_handler {
     if (precision > 0) return digits::more;
     if (precision < 0) return digits::done;
     auto dir = get_round_direction(divisor, remainder, error);
-    if (dir == unknown) return digits::error;
-    buf[size++] = dir == up ? '1' : '0';
+    if (dir == round_direction::unknown) return digits::error;
+    buf[size++] = dir == round_direction::up ? '1' : '0';
     return digits::done;
   }
 
@@ -891,6 +1606,7 @@ struct fixed_handler {
                           uint64_t error, int, bool integral) {
     FMT_ASSERT(remainder < divisor, "");
     buf[size++] = digit;
+    if (!integral && error >= remainder) return digits::error;
     if (size < precision) return digits::more;
     if (!integral) {
       // Check if error * 2 < divisor with overflow prevention.
@@ -901,7 +1617,8 @@ struct fixed_handler {
       FMT_ASSERT(error == 1 && divisor > 2, "");
     }
     auto dir = get_round_direction(divisor, remainder, error);
-    if (dir != up) return dir == down ? digits::done : digits::error;
+    if (dir != round_direction::up)
+      return dir == round_direction::down ? digits::done : digits::error;
     ++buf[size - 1];
     for (int i = size - 1; i > 0 && buf[i] > '9'; --i) {
       buf[i] = '0';
@@ -909,59 +1626,684 @@ struct fixed_handler {
     }
     if (buf[0] > '9') {
       buf[0] = '1';
-      buf[size++] = '0';
+      if (fixed)
+        buf[size++] = '0';
+      else
+        ++exp10;
     }
     return digits::done;
   }
 };
 
-// The shortest representation digit handler.
-struct grisu_shortest_handler {
-  char* buf;
-  int size;
-  // Distance between scaled value and upper bound (wp_W in Grisu3).
-  uint64_t diff;
+// Implementation of Dragonbox algorithm: https://github.com/jk-jeon/dragonbox.
+namespace dragonbox {
+// Computes 128-bit result of multiplication of two 64-bit unsigned integers.
+FMT_SAFEBUFFERS inline uint128_wrapper umul128(uint64_t x,
+                                               uint64_t y) FMT_NOEXCEPT {
+#if FMT_USE_INT128
+  return static_cast<uint128_t>(x) * static_cast<uint128_t>(y);
+#elif defined(_MSC_VER) && defined(_M_X64)
+  uint128_wrapper result;
+  result.low_ = _umul128(x, y, &result.high_);
+  return result;
+#else
+  const uint64_t mask = (uint64_t(1) << 32) - uint64_t(1);
+
+  uint64_t a = x >> 32;
+  uint64_t b = x & mask;
+  uint64_t c = y >> 32;
+  uint64_t d = y & mask;
+
+  uint64_t ac = a * c;
+  uint64_t bc = b * c;
+  uint64_t ad = a * d;
+  uint64_t bd = b * d;
+
+  uint64_t intermediate = (bd >> 32) + (ad & mask) + (bc & mask);
+
+  return {ac + (intermediate >> 32) + (ad >> 32) + (bc >> 32),
+          (intermediate << 32) + (bd & mask)};
+#endif
+}
+
+// Computes upper 64 bits of multiplication of two 64-bit unsigned integers.
+FMT_SAFEBUFFERS inline uint64_t umul128_upper64(uint64_t x,
+                                                uint64_t y) FMT_NOEXCEPT {
+#if FMT_USE_INT128
+  auto p = static_cast<uint128_t>(x) * static_cast<uint128_t>(y);
+  return static_cast<uint64_t>(p >> 64);
+#elif defined(_MSC_VER) && defined(_M_X64)
+  return __umulh(x, y);
+#else
+  return umul128(x, y).high();
+#endif
+}
+
+// Computes upper 64 bits of multiplication of a 64-bit unsigned integer and a
+// 128-bit unsigned integer.
+FMT_SAFEBUFFERS inline uint64_t umul192_upper64(uint64_t x, uint128_wrapper y)
+    FMT_NOEXCEPT {
+  uint128_wrapper g0 = umul128(x, y.high());
+  g0 += umul128_upper64(x, y.low());
+  return g0.high();
+}
+
+// Computes upper 32 bits of multiplication of a 32-bit unsigned integer and a
+// 64-bit unsigned integer.
+inline uint32_t umul96_upper32(uint32_t x, uint64_t y) FMT_NOEXCEPT {
+  return static_cast<uint32_t>(umul128_upper64(x, y));
+}
+
+// Computes middle 64 bits of multiplication of a 64-bit unsigned integer and a
+// 128-bit unsigned integer.
+FMT_SAFEBUFFERS inline uint64_t umul192_middle64(uint64_t x, uint128_wrapper y)
+    FMT_NOEXCEPT {
+  uint64_t g01 = x * y.high();
+  uint64_t g10 = umul128_upper64(x, y.low());
+  return g01 + g10;
+}
+
+// Computes lower 64 bits of multiplication of a 32-bit unsigned integer and a
+// 64-bit unsigned integer.
+inline uint64_t umul96_lower64(uint32_t x, uint64_t y) FMT_NOEXCEPT {
+  return x * y;
+}
+
+// Computes floor(log10(pow(2, e))) for e in [-1700, 1700] using the method from
+// https://fmt.dev/papers/Grisu-Exact.pdf#page=5, section 3.4.
+inline int floor_log10_pow2(int e) FMT_NOEXCEPT {
+  FMT_ASSERT(e <= 1700 && e >= -1700, "too large exponent");
+  const int shift = 22;
+  return (e * static_cast<int>(data::log10_2_significand >> (64 - shift))) >>
+         shift;
+}
+
+// Various fast log computations.
+inline int floor_log2_pow10(int e) FMT_NOEXCEPT {
+  FMT_ASSERT(e <= 1233 && e >= -1233, "too large exponent");
+  const uint64_t log2_10_integer_part = 3;
+  const uint64_t log2_10_fractional_digits = 0x5269e12f346e2bf9;
+  const int shift_amount = 19;
+  return (e * static_cast<int>(
+                  (log2_10_integer_part << shift_amount) |
+                  (log2_10_fractional_digits >> (64 - shift_amount)))) >>
+         shift_amount;
+}
+inline int floor_log10_pow2_minus_log10_4_over_3(int e) FMT_NOEXCEPT {
+  FMT_ASSERT(e <= 1700 && e >= -1700, "too large exponent");
+  const uint64_t log10_4_over_3_fractional_digits = 0x1ffbfc2bbc780375;
+  const int shift_amount = 22;
+  return (e * static_cast<int>(data::log10_2_significand >>
+                               (64 - shift_amount)) -
+          static_cast<int>(log10_4_over_3_fractional_digits >>
+                           (64 - shift_amount))) >>
+         shift_amount;
+}
+
+// Returns true iff x is divisible by pow(2, exp).
+inline bool divisible_by_power_of_2(uint32_t x, int exp) FMT_NOEXCEPT {
+  FMT_ASSERT(exp >= 1, "");
+  FMT_ASSERT(x != 0, "");
+#ifdef FMT_BUILTIN_CTZ
+  return FMT_BUILTIN_CTZ(x) >= exp;
+#else
+  return exp < num_bits<uint32_t>() && x == ((x >> exp) << exp);
+#endif
+}
+inline bool divisible_by_power_of_2(uint64_t x, int exp) FMT_NOEXCEPT {
+  FMT_ASSERT(exp >= 1, "");
+  FMT_ASSERT(x != 0, "");
+#ifdef FMT_BUILTIN_CTZLL
+  return FMT_BUILTIN_CTZLL(x) >= exp;
+#else
+  return exp < num_bits<uint64_t>()) && x == ((x >> exp) << exp);
+#endif
+}
+
+// Returns true iff x is divisible by pow(5, exp).
+inline bool divisible_by_power_of_5(uint32_t x, int exp) FMT_NOEXCEPT {
+  FMT_ASSERT(exp <= 10, "too large exponent");
+  return x * data::divtest_table_for_pow5_32[exp].mod_inv <=
+         data::divtest_table_for_pow5_32[exp].max_quotient;
+}
+inline bool divisible_by_power_of_5(uint64_t x, int exp) FMT_NOEXCEPT {
+  FMT_ASSERT(exp <= 23, "too large exponent");
+  return x * data::divtest_table_for_pow5_64[exp].mod_inv <=
+         data::divtest_table_for_pow5_64[exp].max_quotient;
+}
+
+// Replaces n by floor(n / pow(5, N)) returning true if and only if n is
+// divisible by pow(5, N).
+// Precondition: n <= 2 * pow(5, N + 1).
+template <int N>
+bool check_divisibility_and_divide_by_pow5(uint32_t& n) FMT_NOEXCEPT {
+  static constexpr struct {
+    uint32_t magic_number;
+    int bits_for_comparison;
+    uint32_t threshold;
+    int shift_amount;
+  } infos[] = {{0xcccd, 16, 0x3333, 18}, {0xa429, 8, 0x0a, 20}};
+  constexpr auto info = infos[N - 1];
+  n *= info.magic_number;
+  const uint32_t comparison_mask = (1u << info.bits_for_comparison) - 1;
+  bool result = (n & comparison_mask) <= info.threshold;
+  n >>= info.shift_amount;
+  return result;
+}
+
+// Computes floor(n / pow(10, N)) for small n and N.
+// Precondition: n <= pow(10, N + 1).
+template <int N> uint32_t small_division_by_pow10(uint32_t n) FMT_NOEXCEPT {
+  static constexpr struct {
+    uint32_t magic_number;
+    int shift_amount;
+    uint32_t divisor_times_10;
+  } infos[] = {{0xcccd, 19, 100}, {0xa3d8, 22, 1000}};
+  constexpr auto info = infos[N - 1];
+  FMT_ASSERT(n <= info.divisor_times_10, "n is too large");
+  return n * info.magic_number >> info.shift_amount;
+}
+
+// Computes floor(n / 10^(kappa + 1)) (float)
+inline uint32_t divide_by_10_to_kappa_plus_1(uint32_t n) FMT_NOEXCEPT {
+  return n / float_info<float>::big_divisor;
+}
+// Computes floor(n / 10^(kappa + 1)) (double)
+inline uint64_t divide_by_10_to_kappa_plus_1(uint64_t n) FMT_NOEXCEPT {
+  return umul128_upper64(n, 0x83126e978d4fdf3c) >> 9;
+}
+
+// Various subroutines using pow10 cache
+template <class T> struct cache_accessor;
+
+template <> struct cache_accessor<float> {
+  using carrier_uint = float_info<float>::carrier_uint;
+  using cache_entry_type = uint64_t;
+
+  static uint64_t get_cached_power(int k) FMT_NOEXCEPT {
+    FMT_ASSERT(k >= float_info<float>::min_k && k <= float_info<float>::max_k,
+               "k is out of range");
+    return data::dragonbox_pow10_significands_64[k - float_info<float>::min_k];
+  }
+
+  static carrier_uint compute_mul(carrier_uint u,
+                                  const cache_entry_type& cache) FMT_NOEXCEPT {
+    return umul96_upper32(u, cache);
+  }
+
+  static uint32_t compute_delta(const cache_entry_type& cache,
+                                int beta_minus_1) FMT_NOEXCEPT {
+    return static_cast<uint32_t>(cache >> (64 - 1 - beta_minus_1));
+  }
+
+  static bool compute_mul_parity(carrier_uint two_f,
+                                 const cache_entry_type& cache,
+                                 int beta_minus_1) FMT_NOEXCEPT {
+    FMT_ASSERT(beta_minus_1 >= 1, "");
+    FMT_ASSERT(beta_minus_1 < 64, "");
+
+    return ((umul96_lower64(two_f, cache) >> (64 - beta_minus_1)) & 1) != 0;
+  }
+
+  static carrier_uint compute_left_endpoint_for_shorter_interval_case(
+      const cache_entry_type& cache, int beta_minus_1) FMT_NOEXCEPT {
+    return static_cast<carrier_uint>(
+        (cache - (cache >> (float_info<float>::significand_bits + 2))) >>
+        (64 - float_info<float>::significand_bits - 1 - beta_minus_1));
+  }
+
+  static carrier_uint compute_right_endpoint_for_shorter_interval_case(
+      const cache_entry_type& cache, int beta_minus_1) FMT_NOEXCEPT {
+    return static_cast<carrier_uint>(
+        (cache + (cache >> (float_info<float>::significand_bits + 1))) >>
+        (64 - float_info<float>::significand_bits - 1 - beta_minus_1));
+  }
+
+  static carrier_uint compute_round_up_for_shorter_interval_case(
+      const cache_entry_type& cache, int beta_minus_1) FMT_NOEXCEPT {
+    return (static_cast<carrier_uint>(
+                cache >>
+                (64 - float_info<float>::significand_bits - 2 - beta_minus_1)) +
+            1) /
+           2;
+  }
+};
+
+template <> struct cache_accessor<double> {
+  using carrier_uint = float_info<double>::carrier_uint;
+  using cache_entry_type = uint128_wrapper;
+
+  static uint128_wrapper get_cached_power(int k) FMT_NOEXCEPT {
+    FMT_ASSERT(k >= float_info<double>::min_k && k <= float_info<double>::max_k,
+               "k is out of range");
+
+#if FMT_USE_FULL_CACHE_DRAGONBOX
+    return data::dragonbox_pow10_significands_128[k -
+                                                  float_info<double>::min_k];
+#else
+    static const int compression_ratio = 27;
+
+    // Compute base index.
+    int cache_index = (k - float_info<double>::min_k) / compression_ratio;
+    int kb = cache_index * compression_ratio + float_info<double>::min_k;
+    int offset = k - kb;
+
+    // Get base cache.
+    uint128_wrapper base_cache =
+        data::dragonbox_pow10_significands_128[cache_index];
+    if (offset == 0) return base_cache;
+
+    // Compute the required amount of bit-shift.
+    int alpha = floor_log2_pow10(kb + offset) - floor_log2_pow10(kb) - offset;
+    FMT_ASSERT(alpha > 0 && alpha < 64, "shifting error detected");
+
+    // Try to recover the real cache.
+    uint64_t pow5 = data::powers_of_5_64[offset];
+    uint128_wrapper recovered_cache = umul128(base_cache.high(), pow5);
+    uint128_wrapper middle_low =
+        umul128(base_cache.low() - (kb < 0 ? 1 : 0), pow5);
+
+    recovered_cache += middle_low.high();
+
+    uint64_t high_to_middle = recovered_cache.high() << (64 - alpha);
+    uint64_t middle_to_low = recovered_cache.low() << (64 - alpha);
+
+    recovered_cache =
+        uint128_wrapper{(recovered_cache.low() >> alpha) | high_to_middle,
+                        ((middle_low.low() >> alpha) | middle_to_low)};
+
+    if (kb < 0) recovered_cache += 1;
+
+    // Get error.
+    int error_idx = (k - float_info<double>::min_k) / 16;
+    uint32_t error = (data::dragonbox_pow10_recovery_errors[error_idx] >>
+                      ((k - float_info<double>::min_k) % 16) * 2) &
+                     0x3;
+
+    // Add the error back.
+    FMT_ASSERT(recovered_cache.low() + error >= recovered_cache.low(), "");
+    return {recovered_cache.high(), recovered_cache.low() + error};
+#endif
+  }
+
+  static carrier_uint compute_mul(carrier_uint u,
+                                  const cache_entry_type& cache) FMT_NOEXCEPT {
+    return umul192_upper64(u, cache);
+  }
+
+  static uint32_t compute_delta(cache_entry_type const& cache,
+                                int beta_minus_1) FMT_NOEXCEPT {
+    return static_cast<uint32_t>(cache.high() >> (64 - 1 - beta_minus_1));
+  }
+
+  static bool compute_mul_parity(carrier_uint two_f,
+                                 const cache_entry_type& cache,
+                                 int beta_minus_1) FMT_NOEXCEPT {
+    FMT_ASSERT(beta_minus_1 >= 1, "");
+    FMT_ASSERT(beta_minus_1 < 64, "");
+
+    return ((umul192_middle64(two_f, cache) >> (64 - beta_minus_1)) & 1) != 0;
+  }
+
+  static carrier_uint compute_left_endpoint_for_shorter_interval_case(
+      const cache_entry_type& cache, int beta_minus_1) FMT_NOEXCEPT {
+    return (cache.high() -
+            (cache.high() >> (float_info<double>::significand_bits + 2))) >>
+           (64 - float_info<double>::significand_bits - 1 - beta_minus_1);
+  }
 
-  digits::result on_start(uint64_t, uint64_t, uint64_t, int&) {
-    return digits::more;
+  static carrier_uint compute_right_endpoint_for_shorter_interval_case(
+      const cache_entry_type& cache, int beta_minus_1) FMT_NOEXCEPT {
+    return (cache.high() +
+            (cache.high() >> (float_info<double>::significand_bits + 1))) >>
+           (64 - float_info<double>::significand_bits - 1 - beta_minus_1);
   }
 
-  // Decrement the generated number approaching value from above.
-  void round(uint64_t d, uint64_t divisor, uint64_t& remainder,
-             uint64_t error) {
-    while (
-        remainder < d && error - remainder >= divisor &&
-        (remainder + divisor < d || d - remainder >= remainder + divisor - d)) {
-      --buf[size - 1];
-      remainder += divisor;
+  static carrier_uint compute_round_up_for_shorter_interval_case(
+      const cache_entry_type& cache, int beta_minus_1) FMT_NOEXCEPT {
+    return ((cache.high() >>
+             (64 - float_info<double>::significand_bits - 2 - beta_minus_1)) +
+            1) /
+           2;
+  }
+};
+
+// Various integer checks
+template <class T>
+bool is_left_endpoint_integer_shorter_interval(int exponent) FMT_NOEXCEPT {
+  return exponent >=
+             float_info<
+                 T>::case_shorter_interval_left_endpoint_lower_threshold &&
+         exponent <=
+             float_info<T>::case_shorter_interval_left_endpoint_upper_threshold;
+}
+template <class T>
+bool is_endpoint_integer(typename float_info<T>::carrier_uint two_f,
+                         int exponent, int minus_k) FMT_NOEXCEPT {
+  if (exponent < float_info<T>::case_fc_pm_half_lower_threshold) return false;
+  // For k >= 0.
+  if (exponent <= float_info<T>::case_fc_pm_half_upper_threshold) return true;
+  // For k < 0.
+  if (exponent > float_info<T>::divisibility_check_by_5_threshold) return false;
+  return divisible_by_power_of_5(two_f, minus_k);
+}
+
+template <class T>
+bool is_center_integer(typename float_info<T>::carrier_uint two_f, int exponent,
+                       int minus_k) FMT_NOEXCEPT {
+  // Exponent for 5 is negative.
+  if (exponent > float_info<T>::divisibility_check_by_5_threshold) return false;
+  if (exponent > float_info<T>::case_fc_upper_threshold)
+    return divisible_by_power_of_5(two_f, minus_k);
+  // Both exponents are nonnegative.
+  if (exponent >= float_info<T>::case_fc_lower_threshold) return true;
+  // Exponent for 2 is negative.
+  return divisible_by_power_of_2(two_f, minus_k - exponent + 1);
+}
+
+// Remove trailing zeros from n and return the number of zeros removed (float)
+FMT_ALWAYS_INLINE int remove_trailing_zeros(uint32_t& n) FMT_NOEXCEPT {
+#ifdef FMT_BUILTIN_CTZ
+  int t = FMT_BUILTIN_CTZ(n);
+#else
+  int t = ctz(n);
+#endif
+  if (t > float_info<float>::max_trailing_zeros)
+    t = float_info<float>::max_trailing_zeros;
+
+  const uint32_t mod_inv1 = 0xcccccccd;
+  const uint32_t max_quotient1 = 0x33333333;
+  const uint32_t mod_inv2 = 0xc28f5c29;
+  const uint32_t max_quotient2 = 0x0a3d70a3;
+
+  int s = 0;
+  for (; s < t - 1; s += 2) {
+    if (n * mod_inv2 > max_quotient2) break;
+    n *= mod_inv2;
+  }
+  if (s < t && n * mod_inv1 <= max_quotient1) {
+    n *= mod_inv1;
+    ++s;
+  }
+  n >>= s;
+  return s;
+}
+
+// Removes trailing zeros and returns the number of zeros removed (double)
+FMT_ALWAYS_INLINE int remove_trailing_zeros(uint64_t& n) FMT_NOEXCEPT {
+#ifdef FMT_BUILTIN_CTZLL
+  int t = FMT_BUILTIN_CTZLL(n);
+#else
+  int t = ctzll(n);
+#endif
+  if (t > float_info<double>::max_trailing_zeros)
+    t = float_info<double>::max_trailing_zeros;
+  // Divide by 10^8 and reduce to 32-bits
+  // Since ret_value.significand <= (2^64 - 1) / 1000 < 10^17,
+  // both of the quotient and the r should fit in 32-bits
+
+  const uint32_t mod_inv1 = 0xcccccccd;
+  const uint32_t max_quotient1 = 0x33333333;
+  const uint64_t mod_inv8 = 0xc767074b22e90e21;
+  const uint64_t max_quotient8 = 0x00002af31dc46118;
+
+  // If the number is divisible by 1'0000'0000, work with the quotient
+  if (t >= 8) {
+    auto quotient_candidate = n * mod_inv8;
+
+    if (quotient_candidate <= max_quotient8) {
+      auto quotient = static_cast<uint32_t>(quotient_candidate >> 8);
+
+      int s = 8;
+      for (; s < t; ++s) {
+        if (quotient * mod_inv1 > max_quotient1) break;
+        quotient *= mod_inv1;
+      }
+      quotient >>= (s - 8);
+      n = quotient;
+      return s;
     }
   }
 
-  // Implements Grisu's round_weed.
-  digits::result on_digit(char digit, uint64_t divisor, uint64_t remainder,
-                          uint64_t error, int exp, bool integral) {
-    buf[size++] = digit;
-    if (remainder >= error) return digits::more;
-    uint64_t unit = integral ? 1 : data::powers_of_10_64[-exp];
-    uint64_t up = (diff - 1) * unit;  // wp_Wup
-    round(up, divisor, remainder, error);
-    uint64_t down = (diff + 1) * unit;  // wp_Wdown
-    if (remainder < down && error - remainder >= divisor &&
-        (remainder + divisor < down ||
-         down - remainder > remainder + divisor - down)) {
-      return digits::error;
+  // Otherwise, work with the remainder
+  auto quotient = static_cast<uint32_t>(n / 100000000);
+  auto remainder = static_cast<uint32_t>(n - 100000000 * quotient);
+
+  if (t == 0 || remainder * mod_inv1 > max_quotient1) {
+    return 0;
+  }
+  remainder *= mod_inv1;
+
+  if (t == 1 || remainder * mod_inv1 > max_quotient1) {
+    n = (remainder >> 1) + quotient * 10000000ull;
+    return 1;
+  }
+  remainder *= mod_inv1;
+
+  if (t == 2 || remainder * mod_inv1 > max_quotient1) {
+    n = (remainder >> 2) + quotient * 1000000ull;
+    return 2;
+  }
+  remainder *= mod_inv1;
+
+  if (t == 3 || remainder * mod_inv1 > max_quotient1) {
+    n = (remainder >> 3) + quotient * 100000ull;
+    return 3;
+  }
+  remainder *= mod_inv1;
+
+  if (t == 4 || remainder * mod_inv1 > max_quotient1) {
+    n = (remainder >> 4) + quotient * 10000ull;
+    return 4;
+  }
+  remainder *= mod_inv1;
+
+  if (t == 5 || remainder * mod_inv1 > max_quotient1) {
+    n = (remainder >> 5) + quotient * 1000ull;
+    return 5;
+  }
+  remainder *= mod_inv1;
+
+  if (t == 6 || remainder * mod_inv1 > max_quotient1) {
+    n = (remainder >> 6) + quotient * 100ull;
+    return 6;
+  }
+  remainder *= mod_inv1;
+
+  n = (remainder >> 7) + quotient * 10ull;
+  return 7;
+}
+
+// The main algorithm for shorter interval case
+template <class T>
+FMT_ALWAYS_INLINE FMT_SAFEBUFFERS decimal_fp<T> shorter_interval_case(
+    int exponent) FMT_NOEXCEPT {
+  decimal_fp<T> ret_value;
+  // Compute k and beta
+  const int minus_k = floor_log10_pow2_minus_log10_4_over_3(exponent);
+  const int beta_minus_1 = exponent + floor_log2_pow10(-minus_k);
+
+  // Compute xi and zi
+  using cache_entry_type = typename cache_accessor<T>::cache_entry_type;
+  const cache_entry_type cache = cache_accessor<T>::get_cached_power(-minus_k);
+
+  auto xi = cache_accessor<T>::compute_left_endpoint_for_shorter_interval_case(
+      cache, beta_minus_1);
+  auto zi = cache_accessor<T>::compute_right_endpoint_for_shorter_interval_case(
+      cache, beta_minus_1);
+
+  // If the left endpoint is not an integer, increase it
+  if (!is_left_endpoint_integer_shorter_interval<T>(exponent)) ++xi;
+
+  // Try bigger divisor
+  ret_value.significand = zi / 10;
+
+  // If succeed, remove trailing zeros if necessary and return
+  if (ret_value.significand * 10 >= xi) {
+    ret_value.exponent = minus_k + 1;
+    ret_value.exponent += remove_trailing_zeros(ret_value.significand);
+    return ret_value;
+  }
+
+  // Otherwise, compute the round-up of y
+  ret_value.significand =
+      cache_accessor<T>::compute_round_up_for_shorter_interval_case(
+          cache, beta_minus_1);
+  ret_value.exponent = minus_k;
+
+  // When tie occurs, choose one of them according to the rule
+  if (exponent >= float_info<T>::shorter_interval_tie_lower_threshold &&
+      exponent <= float_info<T>::shorter_interval_tie_upper_threshold) {
+    ret_value.significand = ret_value.significand % 2 == 0
+                                ? ret_value.significand
+                                : ret_value.significand - 1;
+  } else if (ret_value.significand < xi) {
+    ++ret_value.significand;
+  }
+  return ret_value;
+}
+
+template <typename T>
+FMT_SAFEBUFFERS decimal_fp<T> to_decimal(T x) FMT_NOEXCEPT {
+  // Step 1: integer promotion & Schubfach multiplier calculation.
+
+  using carrier_uint = typename float_info<T>::carrier_uint;
+  using cache_entry_type = typename cache_accessor<T>::cache_entry_type;
+  auto br = bit_cast<carrier_uint>(x);
+
+  // Extract significand bits and exponent bits.
+  const carrier_uint significand_mask =
+      (static_cast<carrier_uint>(1) << float_info<T>::significand_bits) - 1;
+  carrier_uint significand = (br & significand_mask);
+  int exponent = static_cast<int>((br & exponent_mask<T>()) >>
+                                  float_info<T>::significand_bits);
+
+  if (exponent != 0) {  // Check if normal.
+    exponent += float_info<T>::exponent_bias - float_info<T>::significand_bits;
+
+    // Shorter interval case; proceed like Schubfach.
+    if (significand == 0) return shorter_interval_case<T>(exponent);
+
+    significand |=
+        (static_cast<carrier_uint>(1) << float_info<T>::significand_bits);
+  } else {
+    // Subnormal case; the interval is always regular.
+    if (significand == 0) return {0, 0};
+    exponent = float_info<T>::min_exponent - float_info<T>::significand_bits;
+  }
+
+  const bool include_left_endpoint = (significand % 2 == 0);
+  const bool include_right_endpoint = include_left_endpoint;
+
+  // Compute k and beta.
+  const int minus_k = floor_log10_pow2(exponent) - float_info<T>::kappa;
+  const cache_entry_type cache = cache_accessor<T>::get_cached_power(-minus_k);
+  const int beta_minus_1 = exponent + floor_log2_pow10(-minus_k);
+
+  // Compute zi and deltai
+  // 10^kappa <= deltai < 10^(kappa + 1)
+  const uint32_t deltai = cache_accessor<T>::compute_delta(cache, beta_minus_1);
+  const carrier_uint two_fc = significand << 1;
+  const carrier_uint two_fr = two_fc | 1;
+  const carrier_uint zi =
+      cache_accessor<T>::compute_mul(two_fr << beta_minus_1, cache);
+
+  // Step 2: Try larger divisor; remove trailing zeros if necessary
+
+  // Using an upper bound on zi, we might be able to optimize the division
+  // better than the compiler; we are computing zi / big_divisor here
+  decimal_fp<T> ret_value;
+  ret_value.significand = divide_by_10_to_kappa_plus_1(zi);
+  uint32_t r = static_cast<uint32_t>(zi - float_info<T>::big_divisor *
+                                              ret_value.significand);
+
+  if (r > deltai) {
+    goto small_divisor_case_label;
+  } else if (r < deltai) {
+    // Exclude the right endpoint if necessary
+    if (r == 0 && !include_right_endpoint &&
+        is_endpoint_integer<T>(two_fr, exponent, minus_k)) {
+      --ret_value.significand;
+      r = float_info<T>::big_divisor;
+      goto small_divisor_case_label;
+    }
+  } else {
+    // r == deltai; compare fractional parts
+    // Check conditions in the order different from the paper
+    // to take advantage of short-circuiting
+    const carrier_uint two_fl = two_fc - 1;
+    if ((!include_left_endpoint ||
+         !is_endpoint_integer<T>(two_fl, exponent, minus_k)) &&
+        !cache_accessor<T>::compute_mul_parity(two_fl, cache, beta_minus_1)) {
+      goto small_divisor_case_label;
     }
-    return 2 * unit <= remainder && remainder <= error - 4 * unit
-               ? digits::done
-               : digits::error;
   }
-};
+  ret_value.exponent = minus_k + float_info<T>::kappa + 1;
+
+  // We may need to remove trailing zeros
+  ret_value.exponent += remove_trailing_zeros(ret_value.significand);
+  return ret_value;
+
+  // Step 3: Find the significand with the smaller divisor
+
+small_divisor_case_label:
+  ret_value.significand *= 10;
+  ret_value.exponent = minus_k + float_info<T>::kappa;
+
+  const uint32_t mask = (1u << float_info<T>::kappa) - 1;
+  auto dist = r - (deltai / 2) + (float_info<T>::small_divisor / 2);
+
+  // Is dist divisible by 2^kappa?
+  if ((dist & mask) == 0) {
+    const bool approx_y_parity =
+        ((dist ^ (float_info<T>::small_divisor / 2)) & 1) != 0;
+    dist >>= float_info<T>::kappa;
+
+    // Is dist divisible by 5^kappa?
+    if (check_divisibility_and_divide_by_pow5<float_info<T>::kappa>(dist)) {
+      ret_value.significand += dist;
+
+      // Check z^(f) >= epsilon^(f)
+      // We have either yi == zi - epsiloni or yi == (zi - epsiloni) - 1,
+      // where yi == zi - epsiloni if and only if z^(f) >= epsilon^(f)
+      // Since there are only 2 possibilities, we only need to care about the
+      // parity. Also, zi and r should have the same parity since the divisor
+      // is an even number
+      if (cache_accessor<T>::compute_mul_parity(two_fc, cache, beta_minus_1) !=
+          approx_y_parity) {
+        --ret_value.significand;
+      } else {
+        // If z^(f) >= epsilon^(f), we might have a tie
+        // when z^(f) == epsilon^(f), or equivalently, when y is an integer
+        if (is_center_integer<T>(two_fc, exponent, minus_k)) {
+          ret_value.significand = ret_value.significand % 2 == 0
+                                      ? ret_value.significand
+                                      : ret_value.significand - 1;
+        }
+      }
+    }
+    // Is dist not divisible by 5^kappa?
+    else {
+      ret_value.significand += dist;
+    }
+  }
+  // Is dist not divisible by 2^kappa?
+  else {
+    // Since we know dist is small, we might be able to optimize the division
+    // better than the compiler; we are computing dist / small_divisor here
+    ret_value.significand +=
+        small_division_by_pow10<float_info<T>::kappa>(dist);
+  }
+  return ret_value;
+}
+}  // namespace dragonbox
 
 // Formats value using a variation of the Fixed-Precision Positive
 // Floating-Point Printout ((FPP)^2) algorithm by Steele & White:
 // https://fmt.dev/p372-steele.pdf.
 template <typename Double>
-void fallback_format(Double d, buffer<char>& buf, int& exp10) {
+void fallback_format(Double d, int num_digits, bool binary32, buffer<char>& buf,
+                     int& exp10) {
   bigint numerator;    // 2 * R in (FPP)^2.
   bigint denominator;  // 2 * S in (FPP)^2.
   // lower and upper are differences between value and corresponding boundaries.
@@ -972,8 +2314,9 @@ void fallback_format(Double d, buffer<char>& buf, int& exp10) {
   // Shift numerator and denominator by an extra bit or two (if lower boundary
   // is closer) to make lower and upper integers. This eliminates multiplication
   // by 2 during later computations.
-  // TODO: handle float
-  int shift = value.assign(d) ? 2 : 1;
+  const bool is_predecessor_closer =
+      binary32 ? value.assign(static_cast<float>(d)) : value.assign(d);
+  int shift = is_predecessor_closer ? 2 : 1;
   uint64_t significand = value.f << shift;
   if (value.e >= 0) {
     numerator.assign(significand);
@@ -1008,42 +2351,76 @@ void fallback_format(Double d, buffer<char>& buf, int& exp10) {
       upper = &upper_store;
     }
   }
-  if (!upper) upper = &lower;
   // Invariant: value == (numerator / denominator) * pow(10, exp10).
-  bool even = (value.f & 1) == 0;
-  int num_digits = 0;
-  char* data = buf.data();
-  for (;;) {
-    int digit = numerator.divmod_assign(denominator);
-    bool low = compare(numerator, lower) - even < 0;  // numerator <[=] lower.
-    // numerator + upper >[=] pow10:
-    bool high = add_compare(numerator, *upper, denominator) + even > 0;
-    data[num_digits++] = static_cast<char>('0' + digit);
-    if (low || high) {
-      if (!low) {
-        ++data[num_digits - 1];
-      } else if (high) {
-        int result = add_compare(numerator, numerator, denominator);
-        // Round half to even.
-        if (result > 0 || (result == 0 && (digit % 2) != 0))
+  if (num_digits < 0) {
+    // Generate the shortest representation.
+    if (!upper) upper = &lower;
+    bool even = (value.f & 1) == 0;
+    num_digits = 0;
+    char* data = buf.data();
+    for (;;) {
+      int digit = numerator.divmod_assign(denominator);
+      bool low = compare(numerator, lower) - even < 0;  // numerator <[=] lower.
+      // numerator + upper >[=] pow10:
+      bool high = add_compare(numerator, *upper, denominator) + even > 0;
+      data[num_digits++] = static_cast<char>('0' + digit);
+      if (low || high) {
+        if (!low) {
           ++data[num_digits - 1];
+        } else if (high) {
+          int result = add_compare(numerator, numerator, denominator);
+          // Round half to even.
+          if (result > 0 || (result == 0 && (digit % 2) != 0))
+            ++data[num_digits - 1];
+        }
+        buf.try_resize(to_unsigned(num_digits));
+        exp10 -= num_digits - 1;
+        return;
       }
-      buf.resize(num_digits);
-      exp10 -= num_digits - 1;
-      return;
+      numerator *= 10;
+      lower *= 10;
+      if (upper != &lower) *upper *= 10;
     }
+  }
+  // Generate the given number of digits.
+  exp10 -= num_digits - 1;
+  if (num_digits == 0) {
+    buf.try_resize(1);
+    denominator *= 10;
+    buf[0] = add_compare(numerator, numerator, denominator) > 0 ? '1' : '0';
+    return;
+  }
+  buf.try_resize(to_unsigned(num_digits));
+  for (int i = 0; i < num_digits - 1; ++i) {
+    int digit = numerator.divmod_assign(denominator);
+    buf[i] = static_cast<char>('0' + digit);
     numerator *= 10;
-    lower *= 10;
-    if (upper != &lower) *upper *= 10;
   }
+  int digit = numerator.divmod_assign(denominator);
+  auto result = add_compare(numerator, numerator, denominator);
+  if (result > 0 || (result == 0 && (digit % 2) != 0)) {
+    if (digit == 9) {
+      const auto overflow = '0' + 10;
+      buf[num_digits - 1] = overflow;
+      // Propagate the carry.
+      for (int i = num_digits - 1; i > 0 && buf[i] == overflow; --i) {
+        buf[i] = '0';
+        ++buf[i - 1];
+      }
+      if (buf[0] == overflow) {
+        buf[0] = '1';
+        ++exp10;
+      }
+      return;
+    }
+    ++digit;
+  }
+  buf[num_digits - 1] = static_cast<char>('0' + digit);
 }
 
-// Formats value using the Grisu algorithm
-// (https://www.cs.tufts.edu/~nr/cs257/archive/florian-loitsch/printf.pdf)
-// if T is a IEEE754 binary32 or binary64 and snprintf otherwise.
 template <typename T>
 int format_float(T value, int precision, float_specs specs, buffer<char>& buf) {
-  static_assert(!std::is_same<T, float>(), "");
+  static_assert(!std::is_same<T, float>::value, "");
   FMT_ASSERT(value >= 0, "value is negative");
 
   const bool fixed = specs.format == float_format::fixed;
@@ -1052,73 +2429,64 @@ int format_float(T value, int precision, float_specs specs, buffer<char>& buf) {
       buf.push_back('0');
       return 0;
     }
-    buf.resize(to_unsigned(precision));
+    buf.try_resize(to_unsigned(precision));
     std::uninitialized_fill_n(buf.data(), precision, '0');
     return -precision;
   }
 
   if (!specs.use_grisu) return snprintf_float(value, precision, specs, buf);
 
+  if (precision < 0) {
+    // Use Dragonbox for the shortest format.
+    if (specs.binary32) {
+      auto dec = dragonbox::to_decimal(static_cast<float>(value));
+      write<char>(buffer_appender<char>(buf), dec.significand);
+      return dec.exponent;
+    }
+    auto dec = dragonbox::to_decimal(static_cast<double>(value));
+    write<char>(buffer_appender<char>(buf), dec.significand);
+    return dec.exponent;
+  }
+
+  // Use Grisu + Dragon4 for the given precision:
+  // https://www.cs.tufts.edu/~nr/cs257/archive/florian-loitsch/printf.pdf.
   int exp = 0;
   const int min_exp = -60;  // alpha in Grisu.
   int cached_exp10 = 0;     // K in Grisu.
-  if (precision != -1) {
-    if (precision > 17) return snprintf_float(value, precision, specs, buf);
-    fp normalized = normalize(fp(value));
-    const auto cached_pow = get_cached_power(
-        min_exp - (normalized.e + fp::significand_size), cached_exp10);
-    normalized = normalized * cached_pow;
-    fixed_handler handler{buf.data(), 0, precision, -cached_exp10, fixed};
-    if (grisu_gen_digits(normalized, 1, exp, handler) == digits::error)
-      return snprintf_float(value, precision, specs, buf);
-    int num_digits = handler.size;
-    if (!fixed) {
-      // Remove trailing zeros.
-      while (num_digits > 0 && buf[num_digits - 1] == '0') {
-        --num_digits;
-        ++exp;
-      }
-    }
-    buf.resize(to_unsigned(num_digits));
+  fp normalized = normalize(fp(value));
+  const auto cached_pow = get_cached_power(
+      min_exp - (normalized.e + fp::significand_size), cached_exp10);
+  normalized = normalized * cached_pow;
+  // Limit precision to the maximum possible number of significant digits in an
+  // IEEE754 double because we don't need to generate zeros.
+  const int max_double_digits = 767;
+  if (precision > max_double_digits) precision = max_double_digits;
+  fixed_handler handler{buf.data(), 0, precision, -cached_exp10, fixed};
+  if (grisu_gen_digits(normalized, 1, exp, handler) == digits::error) {
+    exp += handler.size - cached_exp10 - 1;
+    fallback_format(value, handler.precision, specs.binary32, buf, exp);
   } else {
-    fp fp_value;
-    auto boundaries = specs.binary32
-                          ? fp_value.assign_float_with_boundaries(value)
-                          : fp_value.assign_with_boundaries(value);
-    fp_value = normalize(fp_value);
-    // Find a cached power of 10 such that multiplying value by it will bring
-    // the exponent in the range [min_exp, -32].
-    const fp cached_pow = get_cached_power(
-        min_exp - (fp_value.e + fp::significand_size), cached_exp10);
-    // Multiply value and boundaries by the cached power of 10.
-    fp_value = fp_value * cached_pow;
-    boundaries.lower = multiply(boundaries.lower, cached_pow.f);
-    boundaries.upper = multiply(boundaries.upper, cached_pow.f);
-    assert(min_exp <= fp_value.e && fp_value.e <= -32);
-    --boundaries.lower;  // \tilde{M}^- - 1 ulp -> M^-_{\downarrow}.
-    ++boundaries.upper;  // \tilde{M}^+ + 1 ulp -> M^+_{\uparrow}.
-    // Numbers outside of (lower, upper) definitely do not round to value.
-    grisu_shortest_handler handler{buf.data(), 0,
-                                   boundaries.upper - fp_value.f};
-    auto result =
-        grisu_gen_digits(fp(boundaries.upper, fp_value.e),
-                         boundaries.upper - boundaries.lower, exp, handler);
-    if (result == digits::error) {
-      exp += handler.size - cached_exp10 - 1;
-      fallback_format(value, buf, exp);
-      return exp;
+    exp += handler.exp10;
+    buf.try_resize(to_unsigned(handler.size));
+  }
+  if (!fixed && !specs.showpoint) {
+    // Remove trailing zeros.
+    auto num_digits = buf.size();
+    while (num_digits > 0 && buf[num_digits - 1] == '0') {
+      --num_digits;
+      ++exp;
     }
-    buf.resize(to_unsigned(handler.size));
+    buf.try_resize(num_digits);
   }
-  return exp - cached_exp10;
-}
+  return exp;
+}  // namespace detail
 
 template <typename T>
 int snprintf_float(T value, int precision, float_specs specs,
                    buffer<char>& buf) {
   // Buffer capacity must be non-zero, otherwise MSVC's vsnprintf_s will fail.
   FMT_ASSERT(buf.capacity() > buf.size(), "empty buffer");
-  static_assert(!std::is_same<T, float>(), "");
+  static_assert(!std::is_same<T, float>::value, "");
 
   // Subtract 1 to account for the difference in precision since we use %e for
   // both general and exponent format.
@@ -1127,11 +2495,11 @@ int snprintf_float(T value, int precision, float_specs specs,
     precision = (precision >= 0 ? precision : 6) - 1;
 
   // Build the format string.
-  enum { max_format_size = 7 };  // Ths longest format is "%#.*Le".
+  enum { max_format_size = 7 };  // The longest format is "%#.*Le".
   char format[max_format_size];
   char* format_ptr = format;
   *format_ptr++ = '%';
-  if (specs.trailing_zeros) *format_ptr++ = '#';
+  if (specs.showpoint && specs.format == float_format::hex) *format_ptr++ = '#';
   if (precision >= 0) {
     *format_ptr++ = '.';
     *format_ptr++ = '*';
@@ -1147,30 +2515,32 @@ int snprintf_float(T value, int precision, float_specs specs,
   for (;;) {
     auto begin = buf.data() + offset;
     auto capacity = buf.capacity() - offset;
-#ifdef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
+#ifdef FMT_FUZZ
     if (precision > 100000)
       throw std::runtime_error(
           "fuzz mode - avoid large allocation inside snprintf");
 #endif
     // Suppress the warning about a nonliteral format string.
-    auto snprintf_ptr = FMT_SNPRINTF;
+    // Cannot use auto because of a bug in MinGW (#1532).
+    int (*snprintf_ptr)(char*, size_t, const char*, ...) = FMT_SNPRINTF;
     int result = precision >= 0
                      ? snprintf_ptr(begin, capacity, format, precision, value)
                      : snprintf_ptr(begin, capacity, format, value);
     if (result < 0) {
-      buf.reserve(buf.capacity() + 1);  // The buffer will grow exponentially.
+      // The buffer will grow exponentially.
+      buf.try_reserve(buf.capacity() + 1);
       continue;
     }
-    unsigned size = to_unsigned(result);
+    auto size = to_unsigned(result);
     // Size equal to capacity means that the last character was truncated.
     if (size >= capacity) {
-      buf.reserve(size + offset + 1);  // Add 1 for the terminating '\0'.
+      buf.try_reserve(size + offset + 1);  // Add 1 for the terminating '\0'.
       continue;
     }
     auto is_digit = [](char c) { return c >= '0' && c <= '9'; };
     if (specs.format == float_format::fixed) {
       if (precision == 0) {
-        buf.resize(size);
+        buf.try_resize(size);
         return 0;
       }
       // Find and remove the decimal point.
@@ -1179,12 +2549,12 @@ int snprintf_float(T value, int precision, float_specs specs,
         --p;
       } while (is_digit(*p));
       int fraction_size = static_cast<int>(end - p - 1);
-      std::memmove(p, p + 1, fraction_size);
-      buf.resize(size - 1);
+      std::memmove(p, p + 1, to_unsigned(fraction_size));
+      buf.try_resize(size - 1);
       return -fraction_size;
     }
     if (specs.format == float_format::hex) {
-      buf.resize(size + offset);
+      buf.try_resize(size + offset);
       return 0;
     }
     // Find and parse the exponent.
@@ -1208,25 +2578,86 @@ int snprintf_float(T value, int precision, float_specs specs,
       while (*fraction_end == '0') --fraction_end;
       // Move the fractional part left to get rid of the decimal point.
       fraction_size = static_cast<int>(fraction_end - begin - 1);
-      std::memmove(begin + 1, begin + 2, fraction_size);
+      std::memmove(begin + 1, begin + 2, to_unsigned(fraction_size));
     }
-    buf.resize(fraction_size + offset + 1);
+    buf.try_resize(to_unsigned(fraction_size) + offset + 1);
     return exp - fraction_size;
   }
 }
-}  // namespace internal
 
-template <> struct formatter<internal::bigint> {
+// A public domain branchless UTF-8 decoder by Christopher Wellons:
+// https://github.com/skeeto/branchless-utf8
+/* Decode the next character, c, from buf, reporting errors in e.
+ *
+ * Since this is a branchless decoder, four bytes will be read from the
+ * buffer regardless of the actual length of the next character. This
+ * means the buffer _must_ have at least three bytes of zero padding
+ * following the end of the data stream.
+ *
+ * Errors are reported in e, which will be non-zero if the parsed
+ * character was somehow invalid: invalid byte sequence, non-canonical
+ * encoding, or a surrogate half.
+ *
+ * The function returns a pointer to the next character. When an error
+ * occurs, this pointer will be a guess that depends on the particular
+ * error, but it will always advance at least one byte.
+ */
+inline const char* utf8_decode(const char* buf, uint32_t* c, int* e) {
+  static const int masks[] = {0x00, 0x7f, 0x1f, 0x0f, 0x07};
+  static const uint32_t mins[] = {4194304, 0, 128, 2048, 65536};
+  static const int shiftc[] = {0, 18, 12, 6, 0};
+  static const int shifte[] = {0, 6, 4, 2, 0};
+
+  int len = code_point_length(buf);
+  const char* next = buf + len;
+
+  // Assume a four-byte character and load four bytes. Unused bits are
+  // shifted out.
+  auto s = reinterpret_cast<const unsigned char*>(buf);
+  *c = uint32_t(s[0] & masks[len]) << 18;
+  *c |= uint32_t(s[1] & 0x3f) << 12;
+  *c |= uint32_t(s[2] & 0x3f) << 6;
+  *c |= uint32_t(s[3] & 0x3f) << 0;
+  *c >>= shiftc[len];
+
+  // Accumulate the various error conditions.
+  *e = (*c < mins[len]) << 6;       // non-canonical encoding
+  *e |= ((*c >> 11) == 0x1b) << 7;  // surrogate half?
+  *e |= (*c > 0x10FFFF) << 8;       // out of range?
+  *e |= (s[1] & 0xc0) >> 2;
+  *e |= (s[2] & 0xc0) >> 4;
+  *e |= (s[3]) >> 6;
+  *e ^= 0x2a;  // top two bits of each tail byte correct?
+  *e >>= shifte[len];
+
+  return next;
+}
+
+struct stringifier {
+  template <typename T> FMT_INLINE std::string operator()(T value) const {
+    return to_string(value);
+  }
+  std::string operator()(basic_format_arg<format_context>::handle h) const {
+    memory_buffer buf;
+    format_parse_context parse_ctx({});
+    format_context format_ctx(buffer_appender<char>(buf), {}, {});
+    h.format(parse_ctx, format_ctx);
+    return to_string(buf);
+  }
+};
+}  // namespace detail
+
+template <> struct formatter<detail::bigint> {
   format_parse_context::iterator parse(format_parse_context& ctx) {
     return ctx.begin();
   }
 
-  format_context::iterator format(const internal::bigint& n,
+  format_context::iterator format(const detail::bigint& n,
                                   format_context& ctx) {
     auto out = ctx.out();
     bool first = true;
     for (auto i = n.bigits_.size(); i > 0; --i) {
-      auto value = n.bigits_[i - 1];
+      auto value = n.bigits_[i - 1u];
       if (first) {
         out = format_to(out, "{:x}", value);
         first = false;
@@ -1235,107 +2666,43 @@ template <> struct formatter<internal::bigint> {
       out = format_to(out, "{:08x}", value);
     }
     if (n.exp_ > 0)
-      out = format_to(out, "p{}", n.exp_ * internal::bigint::bigit_bits);
+      out = format_to(out, "p{}", n.exp_ * detail::bigint::bigit_bits);
     return out;
   }
 };
 
-#if FMT_USE_WINDOWS_H
-
-FMT_FUNC internal::utf8_to_utf16::utf8_to_utf16(string_view s) {
-  static const char ERROR_MSG[] = "cannot convert string from UTF-8 to UTF-16";
-  if (s.size() > INT_MAX)
-    FMT_THROW(windows_error(ERROR_INVALID_PARAMETER, ERROR_MSG));
-  int s_size = static_cast<int>(s.size());
-  if (s_size == 0) {
-    // MultiByteToWideChar does not support zero length, handle separately.
-    buffer_.resize(1);
-    buffer_[0] = 0;
-    return;
-  }
-
-  int length = MultiByteToWideChar(CP_UTF8, MB_ERR_INVALID_CHARS, s.data(),
-                                   s_size, nullptr, 0);
-  if (length == 0) FMT_THROW(windows_error(GetLastError(), ERROR_MSG));
-  buffer_.resize(length + 1);
-  length = MultiByteToWideChar(CP_UTF8, MB_ERR_INVALID_CHARS, s.data(), s_size,
-                               &buffer_[0], length);
-  if (length == 0) FMT_THROW(windows_error(GetLastError(), ERROR_MSG));
-  buffer_[length] = 0;
-}
-
-FMT_FUNC internal::utf16_to_utf8::utf16_to_utf8(wstring_view s) {
-  if (int error_code = convert(s)) {
-    FMT_THROW(windows_error(error_code,
-                            "cannot convert string from UTF-16 to UTF-8"));
-  }
-}
-
-FMT_FUNC int internal::utf16_to_utf8::convert(wstring_view s) {
-  if (s.size() > INT_MAX) return ERROR_INVALID_PARAMETER;
-  int s_size = static_cast<int>(s.size());
-  if (s_size == 0) {
-    // WideCharToMultiByte does not support zero length, handle separately.
-    buffer_.resize(1);
-    buffer_[0] = 0;
-    return 0;
-  }
-
-  int length = WideCharToMultiByte(CP_UTF8, 0, s.data(), s_size, nullptr, 0,
-                                   nullptr, nullptr);
-  if (length == 0) return GetLastError();
-  buffer_.resize(length + 1);
-  length = WideCharToMultiByte(CP_UTF8, 0, s.data(), s_size, &buffer_[0],
-                               length, nullptr, nullptr);
-  if (length == 0) return GetLastError();
-  buffer_[length] = 0;
-  return 0;
-}
-
-FMT_FUNC void windows_error::init(int err_code, string_view format_str,
-                                  format_args args) {
-  error_code_ = err_code;
-  memory_buffer buffer;
-  internal::format_windows_error(buffer, err_code, vformat(format_str, args));
-  std::runtime_error& base = *this;
-  base = std::runtime_error(to_string(buffer));
-}
-
-FMT_FUNC void internal::format_windows_error(internal::buffer<char>& out,
-                                             int error_code,
-                                             string_view message) FMT_NOEXCEPT {
-  FMT_TRY {
-    wmemory_buffer buf;
-    buf.resize(inline_buffer_size);
-    for (;;) {
-      wchar_t* system_message = &buf[0];
-      int result = FormatMessageW(
-          FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS, nullptr,
-          error_code, MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), system_message,
-          static_cast<uint32_t>(buf.size()), nullptr);
-      if (result != 0) {
-        utf16_to_utf8 utf8_message;
-        if (utf8_message.convert(system_message) == ERROR_SUCCESS) {
-          internal::writer w(out);
-          w.write(message);
-          w.write(": ");
-          w.write(utf8_message);
-          return;
-        }
-        break;
-      }
-      if (GetLastError() != ERROR_INSUFFICIENT_BUFFER)
-        break;  // Can't get error message, report error code instead.
-      buf.resize(buf.size() * 2);
+FMT_FUNC detail::utf8_to_utf16::utf8_to_utf16(string_view s) {
+  auto transcode = [this](const char* p) {
+    auto cp = uint32_t();
+    auto error = 0;
+    p = utf8_decode(p, &cp, &error);
+    if (error != 0) FMT_THROW(std::runtime_error("invalid utf8"));
+    if (cp <= 0xFFFF) {
+      buffer_.push_back(static_cast<wchar_t>(cp));
+    } else {
+      cp -= 0x10000;
+      buffer_.push_back(static_cast<wchar_t>(0xD800 + (cp >> 10)));
+      buffer_.push_back(static_cast<wchar_t>(0xDC00 + (cp & 0x3FF)));
     }
+    return p;
+  };
+  auto p = s.data();
+  const size_t block_size = 4;  // utf8_decode always reads blocks of 4 chars.
+  if (s.size() >= block_size) {
+    for (auto end = p + s.size() - block_size + 1; p < end;) p = transcode(p);
   }
-  FMT_CATCH(...) {}
-  format_error_code(out, error_code, message);
+  if (auto num_chars_left = s.data() + s.size() - p) {
+    char buf[2 * block_size - 1] = {};
+    memcpy(buf, p, to_unsigned(num_chars_left));
+    p = buf;
+    do {
+      p = transcode(p);
+    } while (p - buf < num_chars_left);
+  }
+  buffer_.push_back(0);
 }
 
-#endif  // FMT_USE_WINDOWS_H
-
-FMT_FUNC void format_system_error(internal::buffer<char>& out, int error_code,
+FMT_FUNC void format_system_error(detail::buffer<char>& out, int error_code,
                                   string_view message) FMT_NOEXCEPT {
   FMT_TRY {
     memory_buffer buf;
@@ -1343,12 +2710,10 @@ FMT_FUNC void format_system_error(internal::buffer<char>& out, int error_code,
     for (;;) {
       char* system_message = &buf[0];
       int result =
-          internal::safe_strerror(error_code, system_message, buf.size());
+          detail::safe_strerror(error_code, system_message, buf.size());
       if (result == 0) {
-        internal::writer w(out);
-        w.write(message);
-        w.write(": ");
-        w.write(system_message);
+        format_to(detail::buffer_appender<char>(out), "{}: {}", message,
+                  system_message);
         return;
       }
       if (result != ERANGE)
@@ -1360,7 +2725,7 @@ FMT_FUNC void format_system_error(internal::buffer<char>& out, int error_code,
   format_error_code(out, error_code, message);
 }
 
-FMT_FUNC void internal::error_handler::on_error(const char* message) {
+FMT_FUNC void detail::error_handler::on_error(const char* message) {
   FMT_THROW(format_error(message));
 }
 
@@ -1369,19 +2734,55 @@ FMT_FUNC void report_system_error(int error_code,
   report_error(format_system_error, error_code, message);
 }
 
-#if FMT_USE_WINDOWS_H
-FMT_FUNC void report_windows_error(int error_code,
-                                   fmt::string_view message) FMT_NOEXCEPT {
-  report_error(internal::format_windows_error, error_code, message);
+FMT_FUNC std::string detail::vformat(string_view format_str, format_args args) {
+  if (format_str.size() == 2 && equal2(format_str.data(), "{}")) {
+    auto arg = args.get(0);
+    if (!arg) error_handler().on_error("argument not found");
+    return visit_format_arg(stringifier(), arg);
+  }
+  memory_buffer buffer;
+  detail::vformat_to(buffer, format_str, args);
+  return to_string(buffer);
 }
+
+#ifdef _WIN32
+namespace detail {
+using dword = conditional_t<sizeof(long) == 4, unsigned long, unsigned>;
+extern "C" __declspec(dllimport) int __stdcall WriteConsoleW(  //
+    void*, const void*, dword, dword*, void*);
+}  // namespace detail
 #endif
 
 FMT_FUNC void vprint(std::FILE* f, string_view format_str, format_args args) {
   memory_buffer buffer;
-  internal::vformat_to(buffer, format_str,
-                       basic_format_args<buffer_context<char>>(args));
-  internal::fwrite_fully(buffer.data(), 1, buffer.size(), f);
+  detail::vformat_to(buffer, format_str,
+                     basic_format_args<buffer_context<char>>(args));
+#ifdef _WIN32
+  auto fd = _fileno(f);
+  if (_isatty(fd)) {
+    detail::utf8_to_utf16 u16(string_view(buffer.data(), buffer.size()));
+    auto written = detail::dword();
+    if (!detail::WriteConsoleW(reinterpret_cast<void*>(_get_osfhandle(fd)),
+                               u16.c_str(), static_cast<uint32_t>(u16.size()),
+                               &written, nullptr)) {
+      FMT_THROW(format_error("failed to write to console"));
+    }
+    return;
+  }
+#endif
+  detail::fwrite_fully(buffer.data(), 1, buffer.size(), f);
+}
+
+#ifdef _WIN32
+// Print assuming legacy (non-Unicode) encoding.
+FMT_FUNC void detail::vprint_mojibake(std::FILE* f, string_view format_str,
+                                      format_args args) {
+  memory_buffer buffer;
+  detail::vformat_to(buffer, format_str,
+                     basic_format_args<buffer_context<char>>(args));
+  fwrite_fully(buffer.data(), 1, buffer.size(), f);
 }
+#endif
 
 FMT_FUNC void vprint(string_view format_str, format_args args) {
   vprint(stdout, format_str, args);
@@ -1389,8 +2790,4 @@ FMT_FUNC void vprint(string_view format_str, format_args args) {
 
 FMT_END_NAMESPACE
 
-#ifdef _MSC_VER
-#  pragma warning(pop)
-#endif
-
 #endif  // FMT_FORMAT_INL_H_
diff --git a/Externals/fmt/include/fmt/format.h b/Externals/fmt/include/fmt/format.h
index 01f41f5cbdd3..3eb27075e0d5 100755
--- a/Externals/fmt/include/fmt/format.h
+++ b/Externals/fmt/include/fmt/format.h
@@ -33,8 +33,6 @@
 #ifndef FMT_FORMAT_H_
 #define FMT_FORMAT_H_
 
-#include "core.h"
-
 #include <algorithm>
 #include <cerrno>
 #include <cmath>
@@ -43,11 +41,7 @@
 #include <memory>
 #include <stdexcept>
 
-#ifdef __clang__
-#  define FMT_CLANG_VERSION (__clang_major__ * 100 + __clang_minor__)
-#else
-#  define FMT_CLANG_VERSION 0
-#endif
+#include "core.h"
 
 #ifdef __INTEL_COMPILER
 #  define FMT_ICC_VERSION __INTEL_COMPILER
@@ -69,27 +63,52 @@
 #  define FMT_HAS_BUILTIN(x) 0
 #endif
 
-#if FMT_HAS_CPP_ATTRIBUTE(fallthrough) && \
-    (__cplusplus >= 201703 || FMT_GCC_VERSION != 0)
+#if FMT_GCC_VERSION || FMT_CLANG_VERSION
+#  define FMT_NOINLINE __attribute__((noinline))
+#else
+#  define FMT_NOINLINE
+#endif
+
+#if __cplusplus == 201103L || __cplusplus == 201402L
+#  if defined(__INTEL_COMPILER) || defined(__PGI)
+#    define FMT_FALLTHROUGH
+#  elif defined(__clang__)
+#    define FMT_FALLTHROUGH [[clang::fallthrough]]
+#  elif FMT_GCC_VERSION >= 700 && \
+      (!defined(__EDG_VERSION__) || __EDG_VERSION__ >= 520)
+#    define FMT_FALLTHROUGH [[gnu::fallthrough]]
+#  else
+#    define FMT_FALLTHROUGH
+#  endif
+#elif FMT_HAS_CPP17_ATTRIBUTE(fallthrough) || \
+    (defined(_MSVC_LANG) && _MSVC_LANG >= 201703L)
 #  define FMT_FALLTHROUGH [[fallthrough]]
 #else
 #  define FMT_FALLTHROUGH
 #endif
 
+#ifndef FMT_MAYBE_UNUSED
+#  if FMT_HAS_CPP17_ATTRIBUTE(maybe_unused)
+#    define FMT_MAYBE_UNUSED [[maybe_unused]]
+#  else
+#    define FMT_MAYBE_UNUSED
+#  endif
+#endif
+
 #ifndef FMT_THROW
 #  if FMT_EXCEPTIONS
-#    if FMT_MSC_VER
+#    if FMT_MSC_VER || FMT_NVCC
 FMT_BEGIN_NAMESPACE
-namespace internal {
+namespace detail {
 template <typename Exception> inline void do_throw(const Exception& x) {
-  // Silence unreachable code warnings in MSVC because these are nearly
-  // impossible to fix in a generic code.
+  // Silence unreachable code warnings in MSVC and NVCC because these
+  // are nearly impossible to fix in a generic code.
   volatile bool b = true;
   if (b) throw x;
 }
-}  // namespace internal
+}  // namespace detail
 FMT_END_NAMESPACE
-#      define FMT_THROW(x) internal::do_throw(x)
+#      define FMT_THROW(x) detail::do_throw(x)
 #    else
 #      define FMT_THROW(x) throw x
 #    endif
@@ -102,12 +121,19 @@ FMT_END_NAMESPACE
 #  endif
 #endif
 
+#if FMT_EXCEPTIONS
+#  define FMT_TRY try
+#  define FMT_CATCH(x) catch (x)
+#else
+#  define FMT_TRY if (true)
+#  define FMT_CATCH(x) if (false)
+#endif
+
 #ifndef FMT_USE_USER_DEFINED_LITERALS
-// For Intel and NVIDIA compilers both they and the system gcc/msc support UDLs.
-#  if (FMT_HAS_FEATURE(cxx_user_literals) || FMT_GCC_VERSION >= 407 ||      \
-       FMT_MSC_VER >= 1900) &&                                              \
-      (!(FMT_ICC_VERSION || FMT_CUDA_VERSION) || FMT_ICC_VERSION >= 1500 || \
-       FMT_CUDA_VERSION >= 700)
+// EDG based compilers (Intel, NVIDIA, Elbrus, etc), GCC and MSVC support UDLs.
+#  if (FMT_HAS_FEATURE(cxx_user_literals) || FMT_GCC_VERSION >= 407 || \
+       FMT_MSC_VER >= 1900) &&                                         \
+      (!defined(__EDG_VERSION__) || __EDG_VERSION__ >= /* UDL feature */ 480)
 #    define FMT_USE_USER_DEFINED_LITERALS 1
 #  else
 #    define FMT_USE_USER_DEFINED_LITERALS 0
@@ -115,19 +141,39 @@ FMT_END_NAMESPACE
 #endif
 
 #ifndef FMT_USE_UDL_TEMPLATE
-// EDG front end based compilers (icc, nvcc) do not support UDL templates yet
-// and GCC 9 warns about them.
-#  if FMT_USE_USER_DEFINED_LITERALS && FMT_ICC_VERSION == 0 && \
-      FMT_CUDA_VERSION == 0 &&                                 \
-      ((FMT_GCC_VERSION >= 600 && FMT_GCC_VERSION <= 900 &&    \
-        __cplusplus >= 201402L) ||                             \
-       FMT_CLANG_VERSION >= 304)
+// EDG frontend based compilers (icc, nvcc, PGI, etc) and GCC < 6.4 do not
+// properly support UDL templates and GCC >= 9 warns about them.
+#  if FMT_USE_USER_DEFINED_LITERALS &&                         \
+      (!defined(__EDG_VERSION__) || __EDG_VERSION__ >= 501) && \
+      ((FMT_GCC_VERSION >= 604 && __cplusplus >= 201402L) ||   \
+       FMT_CLANG_VERSION >= 304) &&                            \
+      !defined(__PGI) && !defined(__NVCC__)
 #    define FMT_USE_UDL_TEMPLATE 1
 #  else
 #    define FMT_USE_UDL_TEMPLATE 0
 #  endif
 #endif
 
+#ifndef FMT_USE_FLOAT
+#  define FMT_USE_FLOAT 1
+#endif
+
+#ifndef FMT_USE_DOUBLE
+#  define FMT_USE_DOUBLE 1
+#endif
+
+#ifndef FMT_USE_LONG_DOUBLE
+#  define FMT_USE_LONG_DOUBLE 1
+#endif
+
+// Defining FMT_REDUCE_INT_INSTANTIATIONS to 1, will reduce the number of
+// int_writer template instances to just one by only using the largest integer
+// type. This results in a reduction in binary size but will cause a decrease in
+// integer formatting performance.
+#if !defined(FMT_REDUCE_INT_INSTANTIATIONS)
+#  define FMT_REDUCE_INT_INSTANTIATIONS 0
+#endif
+
 // __builtin_clz is broken in clang with Microsoft CodeGen:
 // https://github.com/fmtlib/fmt/issues/519
 #if (FMT_GCC_VERSION || FMT_HAS_BUILTIN(__builtin_clz)) && !FMT_MSC_VER
@@ -136,76 +182,98 @@ FMT_END_NAMESPACE
 #if (FMT_GCC_VERSION || FMT_HAS_BUILTIN(__builtin_clzll)) && !FMT_MSC_VER
 #  define FMT_BUILTIN_CLZLL(n) __builtin_clzll(n)
 #endif
+#if (FMT_GCC_VERSION || FMT_HAS_BUILTIN(__builtin_ctz))
+#  define FMT_BUILTIN_CTZ(n) __builtin_ctz(n)
+#endif
+#if (FMT_GCC_VERSION || FMT_HAS_BUILTIN(__builtin_ctzll))
+#  define FMT_BUILTIN_CTZLL(n) __builtin_ctzll(n)
+#endif
+
+#if FMT_MSC_VER
+#  include <intrin.h>  // _BitScanReverse[64], _BitScanForward[64], _umul128
+#endif
 
 // Some compilers masquerade as both MSVC and GCC-likes or otherwise support
 // __builtin_clz and __builtin_clzll, so only define FMT_BUILTIN_CLZ using the
 // MSVC intrinsics if the clz and clzll builtins are not available.
-#if FMT_MSC_VER && !defined(FMT_BUILTIN_CLZLL) && !defined(_MANAGED)
-#  include <intrin.h>  // _BitScanReverse, _BitScanReverse64
-
+#if FMT_MSC_VER && !defined(FMT_BUILTIN_CLZLL) && \
+    !defined(FMT_BUILTIN_CTZLL) && !defined(_MANAGED)
 FMT_BEGIN_NAMESPACE
-namespace internal {
+namespace detail {
 // Avoid Clang with Microsoft CodeGen's -Wunknown-pragmas warning.
 #  ifndef __clang__
+#    pragma intrinsic(_BitScanForward)
 #    pragma intrinsic(_BitScanReverse)
 #  endif
-inline uint32_t clz(uint32_t x) {
+#  if defined(_WIN64) && !defined(__clang__)
+#    pragma intrinsic(_BitScanForward64)
+#    pragma intrinsic(_BitScanReverse64)
+#  endif
+
+inline int clz(uint32_t x) {
   unsigned long r = 0;
   _BitScanReverse(&r, x);
-
   FMT_ASSERT(x != 0, "");
   // Static analysis complains about using uninitialized data
   // "r", but the only way that can happen is if "x" is 0,
   // which the callers guarantee to not happen.
-#  pragma warning(suppress : 6102)
-  return 31 - r;
+  FMT_SUPPRESS_MSC_WARNING(6102)
+  return 31 ^ static_cast<int>(r);
 }
-#  define FMT_BUILTIN_CLZ(n) internal::clz(n)
+#  define FMT_BUILTIN_CLZ(n) detail::clz(n)
 
-#  if defined(_WIN64) && !defined(__clang__)
-#    pragma intrinsic(_BitScanReverse64)
-#  endif
-
-inline uint32_t clzll(uint64_t x) {
+inline int clzll(uint64_t x) {
   unsigned long r = 0;
 #  ifdef _WIN64
   _BitScanReverse64(&r, x);
 #  else
   // Scan the high 32 bits.
-  if (_BitScanReverse(&r, static_cast<uint32_t>(x >> 32))) return 63 - (r + 32);
-
+  if (_BitScanReverse(&r, static_cast<uint32_t>(x >> 32))) return 63 ^ (r + 32);
   // Scan the low 32 bits.
   _BitScanReverse(&r, static_cast<uint32_t>(x));
 #  endif
+  FMT_ASSERT(x != 0, "");
+  FMT_SUPPRESS_MSC_WARNING(6102)  // Suppress a bogus static analysis warning.
+  return 63 ^ static_cast<int>(r);
+}
+#  define FMT_BUILTIN_CLZLL(n) detail::clzll(n)
 
+inline int ctz(uint32_t x) {
+  unsigned long r = 0;
+  _BitScanForward(&r, x);
   FMT_ASSERT(x != 0, "");
-  // Static analysis complains about using uninitialized data
-  // "r", but the only way that can happen is if "x" is 0,
-  // which the callers guarantee to not happen.
-#  pragma warning(suppress : 6102)
-  return 63 - r;
+  FMT_SUPPRESS_MSC_WARNING(6102)  // Suppress a bogus static analysis warning.
+  return static_cast<int>(r);
+}
+#  define FMT_BUILTIN_CTZ(n) detail::ctz(n)
+
+inline int ctzll(uint64_t x) {
+  unsigned long r = 0;
+  FMT_ASSERT(x != 0, "");
+  FMT_SUPPRESS_MSC_WARNING(6102)  // Suppress a bogus static analysis warning.
+#  ifdef _WIN64
+  _BitScanForward64(&r, x);
+#  else
+  // Scan the low 32 bits.
+  if (_BitScanForward(&r, static_cast<uint32_t>(x))) return static_cast<int>(r);
+  // Scan the high 32 bits.
+  _BitScanForward(&r, static_cast<uint32_t>(x >> 32));
+  r += 32;
+#  endif
+  return static_cast<int>(r);
 }
-#  define FMT_BUILTIN_CLZLL(n) internal::clzll(n)
-}  // namespace internal
+#  define FMT_BUILTIN_CTZLL(n) detail::ctzll(n)
+}  // namespace detail
 FMT_END_NAMESPACE
 #endif
 
 // Enable the deprecated numeric alignment.
-#ifndef FMT_NUMERIC_ALIGN
-#  define FMT_NUMERIC_ALIGN 1
-#endif
-
-// Enable the deprecated percent specifier.
-#ifndef FMT_DEPRECATED_PERCENT
-#  define FMT_DEPRECATED_PERCENT 0
+#ifndef FMT_DEPRECATED_NUMERIC_ALIGN
+#  define FMT_DEPRECATED_NUMERIC_ALIGN 0
 #endif
 
 FMT_BEGIN_NAMESPACE
-namespace internal {
-
-// A helper function to suppress bogus "conditional expression is constant"
-// warnings.
-template <typename T> inline T const_check(T value) { return value; }
+namespace detail {
 
 // An equivalent of `*reinterpret_cast<Dest*>(&source)` that doesn't have
 // undefined behavior (e.g. due to type aliasing).
@@ -219,7 +287,7 @@ inline Dest bit_cast(const Source& source) {
 }
 
 inline bool is_big_endian() {
-  auto u = 1u;
+  const auto u = 1u;
   struct bytes {
     char data[sizeof(u)];
   };
@@ -257,47 +325,25 @@ template <typename T> constexpr T max_value() {
 template <typename T> constexpr int num_bits() {
   return std::numeric_limits<T>::digits;
 }
+// std::numeric_limits<T>::digits may return 0 for 128-bit ints.
+template <> constexpr int num_bits<int128_t>() { return 128; }
+template <> constexpr int num_bits<uint128_t>() { return 128; }
 template <> constexpr int num_bits<fallback_uintptr>() {
   return static_cast<int>(sizeof(void*) *
                           std::numeric_limits<unsigned char>::digits);
 }
 
+FMT_INLINE void assume(bool condition) {
+  (void)condition;
+#if FMT_HAS_BUILTIN(__builtin_assume)
+  __builtin_assume(condition);
+#endif
+}
+
 // An approximation of iterator_t for pre-C++20 systems.
 template <typename T>
 using iterator_t = decltype(std::begin(std::declval<T&>()));
-
-// Detect the iterator category of *any* given type in a SFINAE-friendly way.
-// Unfortunately, older implementations of std::iterator_traits are not safe
-// for use in a SFINAE-context.
-template <typename It, typename Enable = void>
-struct iterator_category : std::false_type {};
-
-template <typename T> struct iterator_category<T*> {
-  using type = std::random_access_iterator_tag;
-};
-
-template <typename It>
-struct iterator_category<It, void_t<typename It::iterator_category>> {
-  using type = typename It::iterator_category;
-};
-
-// Detect if *any* given type models the OutputIterator concept.
-template <typename It> class is_output_iterator {
-  // Check for mutability because all iterator categories derived from
-  // std::input_iterator_tag *may* also meet the requirements of an
-  // OutputIterator, thereby falling into the category of 'mutable iterators'
-  // [iterator.requirements.general] clause 4. The compiler reveals this
-  // property only at the point of *actually dereferencing* the iterator!
-  template <typename U>
-  static decltype(*(std::declval<U>())) test(std::input_iterator_tag);
-  template <typename U> static char& test(std::output_iterator_tag);
-  template <typename U> static const char& test(...);
-
-  using type = decltype(test<It>(typename iterator_category<It>::type{}));
-
- public:
-  static const bool value = !std::is_const<remove_reference_t<type>>::value;
-};
+template <typename T> using sentinel_t = decltype(std::end(std::declval<T&>()));
 
 // A workaround for std::string not having mutable data() until C++17.
 template <typename Char> inline Char* get_data(std::basic_string<Char>& s) {
@@ -308,28 +354,61 @@ inline typename Container::value_type* get_data(Container& c) {
   return c.data();
 }
 
-#ifdef _SECURE_SCL
+#if defined(_SECURE_SCL) && _SECURE_SCL
 // Make a checked iterator to avoid MSVC warnings.
 template <typename T> using checked_ptr = stdext::checked_array_iterator<T*>;
-template <typename T> checked_ptr<T> make_checked(T* p, std::size_t size) {
+template <typename T> checked_ptr<T> make_checked(T* p, size_t size) {
   return {p, size};
 }
 #else
 template <typename T> using checked_ptr = T*;
-template <typename T> inline T* make_checked(T* p, std::size_t) { return p; }
+template <typename T> inline T* make_checked(T* p, size_t) { return p; }
 #endif
 
 template <typename Container, FMT_ENABLE_IF(is_contiguous<Container>::value)>
-inline checked_ptr<typename Container::value_type> reserve(
-    std::back_insert_iterator<Container>& it, std::size_t n) {
+#if FMT_CLANG_VERSION
+__attribute__((no_sanitize("undefined")))
+#endif
+inline checked_ptr<typename Container::value_type>
+reserve(std::back_insert_iterator<Container> it, size_t n) {
   Container& c = get_container(it);
-  std::size_t size = c.size();
+  size_t size = c.size();
   c.resize(size + n);
   return make_checked(get_data(c) + size, n);
 }
 
+template <typename T>
+inline buffer_appender<T> reserve(buffer_appender<T> it, size_t n) {
+  buffer<T>& buf = get_container(it);
+  buf.try_reserve(buf.size() + n);
+  return it;
+}
+
+template <typename Iterator> inline Iterator& reserve(Iterator& it, size_t) {
+  return it;
+}
+
+template <typename T, typename OutputIt>
+constexpr T* to_pointer(OutputIt, size_t) {
+  return nullptr;
+}
+template <typename T> T* to_pointer(buffer_appender<T> it, size_t n) {
+  buffer<T>& buf = get_container(it);
+  auto size = buf.size();
+  if (buf.capacity() < size + n) return nullptr;
+  buf.try_resize(size + n);
+  return buf.data() + size;
+}
+
+template <typename Container, FMT_ENABLE_IF(is_contiguous<Container>::value)>
+inline std::back_insert_iterator<Container> base_iterator(
+    std::back_insert_iterator<Container>& it,
+    checked_ptr<typename Container::value_type>) {
+  return it;
+}
+
 template <typename Iterator>
-inline Iterator& reserve(Iterator& it, std::size_t) {
+inline Iterator base_iterator(Iterator, Iterator it) {
   return it;
 }
 
@@ -337,7 +416,7 @@ inline Iterator& reserve(Iterator& it, std::size_t) {
 // discards them.
 class counting_iterator {
  private:
-  std::size_t count_;
+  size_t count_;
 
  public:
   using iterator_category = std::output_iterator_tag;
@@ -352,33 +431,38 @@ class counting_iterator {
 
   counting_iterator() : count_(0) {}
 
-  std::size_t count() const { return count_; }
+  size_t count() const { return count_; }
 
   counting_iterator& operator++() {
     ++count_;
     return *this;
   }
-
   counting_iterator operator++(int) {
     auto it = *this;
     ++*this;
     return it;
   }
 
+  friend counting_iterator operator+(counting_iterator it, difference_type n) {
+    it.count_ += static_cast<size_t>(n);
+    return it;
+  }
+
   value_type operator*() const { return {}; }
 };
 
 template <typename OutputIt> class truncating_iterator_base {
  protected:
   OutputIt out_;
-  std::size_t limit_;
-  std::size_t count_;
+  size_t limit_;
+  size_t count_;
 
-  truncating_iterator_base(OutputIt out, std::size_t limit)
+  truncating_iterator_base(OutputIt out, size_t limit)
       : out_(out), limit_(limit), count_(0) {}
 
  public:
   using iterator_category = std::output_iterator_tag;
+  using value_type = typename std::iterator_traits<OutputIt>::value_type;
   using difference_type = void;
   using pointer = void;
   using reference = void;
@@ -386,7 +470,7 @@ template <typename OutputIt> class truncating_iterator_base {
       truncating_iterator_base;  // Mark iterator as checked.
 
   OutputIt base() const { return out_; }
-  std::size_t count() const { return count_; }
+  size_t count() const { return count_; }
 };
 
 // An output iterator that truncates the output and counts the number of objects
@@ -399,14 +483,12 @@ class truncating_iterator;
 template <typename OutputIt>
 class truncating_iterator<OutputIt, std::false_type>
     : public truncating_iterator_base<OutputIt> {
-  using traits = std::iterator_traits<OutputIt>;
-
-  mutable typename traits::value_type blackhole_;
+  mutable typename truncating_iterator_base<OutputIt>::value_type blackhole_;
 
  public:
-  using value_type = typename traits::value_type;
+  using value_type = typename truncating_iterator_base<OutputIt>::value_type;
 
-  truncating_iterator(OutputIt out, std::size_t limit)
+  truncating_iterator(OutputIt out, size_t limit)
       : truncating_iterator_base<OutputIt>(out, limit) {}
 
   truncating_iterator& operator++() {
@@ -429,13 +511,11 @@ template <typename OutputIt>
 class truncating_iterator<OutputIt, std::true_type>
     : public truncating_iterator_base<OutputIt> {
  public:
-  using value_type = typename OutputIt::container_type::value_type;
-
-  truncating_iterator(OutputIt out, std::size_t limit)
+  truncating_iterator(OutputIt out, size_t limit)
       : truncating_iterator_base<OutputIt>(out, limit) {}
 
-  truncating_iterator& operator=(value_type val) {
-    if (this->count_++ < this->limit_) this->out_ = val;
+  template <typename T> truncating_iterator& operator=(T val) {
+    if (this->count_++ < this->limit_) *this->out_++ = val;
     return *this;
   }
 
@@ -444,30 +524,14 @@ class truncating_iterator<OutputIt, std::true_type>
   truncating_iterator& operator*() { return *this; }
 };
 
-// A range with the specified output iterator and value type.
-template <typename OutputIt, typename T = typename OutputIt::value_type>
-class output_range {
- private:
-  OutputIt it_;
-
- public:
-  using value_type = T;
-  using iterator = OutputIt;
-  struct sentinel {};
-
-  explicit output_range(OutputIt it) : it_(it) {}
-  OutputIt begin() const { return it_; }
-  sentinel end() const { return {}; }  // Sentinel is not used yet.
-};
-
 template <typename Char>
 inline size_t count_code_points(basic_string_view<Char> s) {
   return s.size();
 }
 
 // Counts the number of code points in a UTF-8 string.
-inline size_t count_code_points(basic_string_view<char8_t> s) {
-  const char8_t* data = s.data();
+inline size_t count_code_points(basic_string_view<char> s) {
+  const char* data = s.data();
   size_t num_code_points = 0;
   for (size_t i = 0, size = s.size(); i != size; ++i) {
     if ((data[i] & 0xc0) != 0x80) ++num_code_points;
@@ -475,6 +539,11 @@ inline size_t count_code_points(basic_string_view<char8_t> s) {
   return num_code_points;
 }
 
+inline size_t count_code_points(basic_string_view<char8_type> s) {
+  return count_code_points(basic_string_view<char>(
+      reinterpret_cast<const char*>(s.data()), s.size()));
+}
+
 template <typename Char>
 inline size_t code_point_index(basic_string_view<Char> s, size_t n) {
   size_t size = s.size();
@@ -482,8 +551,8 @@ inline size_t code_point_index(basic_string_view<Char> s, size_t n) {
 }
 
 // Calculates the index of the nth code point in a UTF-8 string.
-inline size_t code_point_index(basic_string_view<char8_t> s, size_t n) {
-  const char8_t* data = s.data();
+inline size_t code_point_index(basic_string_view<char8_type> s, size_t n) {
+  const char8_type* data = s.data();
   size_t num_code_points = 0;
   for (size_t i = 0, size = s.size(); i != size; ++i) {
     if ((data[i] & 0xc0) != 0x80 && ++num_code_points > n) {
@@ -493,13 +562,11 @@ inline size_t code_point_index(basic_string_view<char8_t> s, size_t n) {
   return s.size();
 }
 
-inline char8_t to_char8_t(char c) { return static_cast<char8_t>(c); }
-
 template <typename InputIt, typename OutChar>
 using needs_conversion = bool_constant<
     std::is_same<typename std::iterator_traits<InputIt>::value_type,
                  char>::value &&
-    std::is_same<OutChar, char8_t>::value>;
+    std::is_same<OutChar, char8_type>::value>;
 
 template <typename OutChar, typename InputIt, typename OutputIt,
           FMT_ENABLE_IF(!needs_conversion<InputIt, OutChar>::value)>
@@ -510,56 +577,44 @@ OutputIt copy_str(InputIt begin, InputIt end, OutputIt it) {
 template <typename OutChar, typename InputIt, typename OutputIt,
           FMT_ENABLE_IF(needs_conversion<InputIt, OutChar>::value)>
 OutputIt copy_str(InputIt begin, InputIt end, OutputIt it) {
-  return std::transform(begin, end, it, to_char8_t);
+  return std::transform(begin, end, it,
+                        [](char c) { return static_cast<char8_type>(c); });
 }
 
-#ifndef FMT_USE_GRISU
-#  define FMT_USE_GRISU 1
-#endif
-
-template <typename T> constexpr bool use_grisu() {
-  return FMT_USE_GRISU && std::numeric_limits<double>::is_iec559 &&
-         sizeof(T) <= sizeof(double);
+template <typename Char, typename InputIt>
+inline counting_iterator copy_str(InputIt begin, InputIt end,
+                                  counting_iterator it) {
+  return it + (end - begin);
 }
 
+template <typename T>
+using is_fast_float = bool_constant<std::numeric_limits<T>::is_iec559 &&
+                                    sizeof(T) <= sizeof(double)>;
+
+#ifndef FMT_USE_FULL_CACHE_DRAGONBOX
+#  define FMT_USE_FULL_CACHE_DRAGONBOX 0
+#endif
+
 template <typename T>
 template <typename U>
 void buffer<T>::append(const U* begin, const U* end) {
-  std::size_t new_size = size_ + to_unsigned(end - begin);
-  reserve(new_size);
-  std::uninitialized_copy(begin, end, make_checked(ptr_, capacity_) + size_);
-  size_ = new_size;
+  do {
+    auto count = to_unsigned(end - begin);
+    try_reserve(size_ + count);
+    auto free_cap = capacity_ - size_;
+    if (free_cap < count) count = free_cap;
+    std::uninitialized_copy_n(begin, count, make_checked(ptr_ + size_, count));
+    size_ += count;
+    begin += count;
+  } while (begin != end);
 }
-}  // namespace internal
-
-// A range with an iterator appending to a buffer.
-template <typename T>
-class buffer_range : public internal::output_range<
-                         std::back_insert_iterator<internal::buffer<T>>, T> {
- public:
-  using iterator = std::back_insert_iterator<internal::buffer<T>>;
-  using internal::output_range<iterator, T>::output_range;
-  buffer_range(internal::buffer<T>& buf)
-      : internal::output_range<iterator, T>(std::back_inserter(buf)) {}
-};
 
-// A UTF-8 string view.
-class u8string_view : public basic_string_view<char8_t> {
- public:
-  u8string_view(const char* s)
-      : basic_string_view<char8_t>(reinterpret_cast<const char8_t*>(s)) {}
-  u8string_view(const char* s, size_t count) FMT_NOEXCEPT
-      : basic_string_view<char8_t>(reinterpret_cast<const char8_t*>(s), count) {
-  }
-};
-
-#if FMT_USE_USER_DEFINED_LITERALS
-inline namespace literals {
-inline u8string_view operator"" _u(const char* s, std::size_t n) {
-  return {s, n};
+template <typename OutputIt, typename T, typename Traits>
+void iterator_buffer<OutputIt, T, Traits>::flush() {
+  out_ = std::copy_n(data_, this->limit(this->size()), out_);
+  this->clear();
 }
-}  // namespace literals
-#endif
+}  // namespace detail
 
 // The number of characters to store in the basic_memory_buffer object itself
 // to avoid dynamic memory allocation.
@@ -594,42 +649,44 @@ enum { inline_buffer_size = 500 };
   The output can be converted to an ``std::string`` with ``to_string(out)``.
   \endrst
  */
-template <typename T, std::size_t SIZE = inline_buffer_size,
+template <typename T, size_t SIZE = inline_buffer_size,
           typename Allocator = std::allocator<T>>
-class basic_memory_buffer : private Allocator, public internal::buffer<T> {
+class basic_memory_buffer final : public detail::buffer<T> {
  private:
   T store_[SIZE];
 
+  // Don't inherit from Allocator avoid generating type_info for it.
+  Allocator alloc_;
+
   // Deallocate memory allocated by the buffer.
   void deallocate() {
     T* data = this->data();
-    if (data != store_) Allocator::deallocate(data, this->capacity());
+    if (data != store_) alloc_.deallocate(data, this->capacity());
   }
 
  protected:
-  void grow(std::size_t size) FMT_OVERRIDE;
+  void grow(size_t size) final FMT_OVERRIDE;
 
  public:
   using value_type = T;
   using const_reference = const T&;
 
   explicit basic_memory_buffer(const Allocator& alloc = Allocator())
-      : Allocator(alloc) {
+      : alloc_(alloc) {
     this->set(store_, SIZE);
   }
-  ~basic_memory_buffer() FMT_OVERRIDE { deallocate(); }
+  ~basic_memory_buffer() { deallocate(); }
 
  private:
   // Move data from other to this buffer.
   void move(basic_memory_buffer& other) {
-    Allocator &this_alloc = *this, &other_alloc = other;
-    this_alloc = std::move(other_alloc);
+    alloc_ = std::move(other.alloc_);
     T* data = other.data();
-    std::size_t size = other.size(), capacity = other.capacity();
+    size_t size = other.size(), capacity = other.capacity();
     if (data == other.store_) {
       this->set(store_, capacity);
       std::uninitialized_copy(other.store_, other.store_ + size,
-                              internal::make_checked(store_, capacity));
+                              detail::make_checked(store_, capacity));
     } else {
       this->set(data, capacity);
       // Set pointer to the inline array so that delete is not called
@@ -661,33 +718,55 @@ class basic_memory_buffer : private Allocator, public internal::buffer<T> {
   }
 
   // Returns a copy of the allocator associated with this buffer.
-  Allocator get_allocator() const { return *this; }
+  Allocator get_allocator() const { return alloc_; }
+
+  /**
+    Resizes the buffer to contain *count* elements. If T is a POD type new
+    elements may not be initialized.
+   */
+  void resize(size_t count) { this->try_resize(count); }
+
+  /** Increases the buffer capacity to *new_capacity*. */
+  void reserve(size_t new_capacity) { this->try_reserve(new_capacity); }
+
+  // Directly append data into the buffer
+  using detail::buffer<T>::append;
+  template <typename ContiguousRange>
+  void append(const ContiguousRange& range) {
+    append(range.data(), range.data() + range.size());
+  }
 };
 
-template <typename T, std::size_t SIZE, typename Allocator>
-void basic_memory_buffer<T, SIZE, Allocator>::grow(std::size_t size) {
-#ifdef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
-  if (size > 1000) throw std::runtime_error("fuzz mode - won't grow that much");
+template <typename T, size_t SIZE, typename Allocator>
+void basic_memory_buffer<T, SIZE, Allocator>::grow(size_t size) {
+#ifdef FMT_FUZZ
+  if (size > 5000) throw std::runtime_error("fuzz mode - won't grow that much");
 #endif
-  std::size_t old_capacity = this->capacity();
-  std::size_t new_capacity = old_capacity + old_capacity / 2;
+  size_t old_capacity = this->capacity();
+  size_t new_capacity = old_capacity + old_capacity / 2;
   if (size > new_capacity) new_capacity = size;
   T* old_data = this->data();
-  T* new_data = std::allocator_traits<Allocator>::allocate(*this, new_capacity);
+  T* new_data =
+      std::allocator_traits<Allocator>::allocate(alloc_, new_capacity);
   // The following code doesn't throw, so the raw pointer above doesn't leak.
   std::uninitialized_copy(old_data, old_data + this->size(),
-                          internal::make_checked(new_data, new_capacity));
+                          detail::make_checked(new_data, new_capacity));
   this->set(new_data, new_capacity);
   // deallocate must not throw according to the standard, but even if it does,
   // the buffer already uses the new storage and will deallocate it in
   // destructor.
-  if (old_data != store_) Allocator::deallocate(old_data, old_capacity);
+  if (old_data != store_) alloc_.deallocate(old_data, old_capacity);
 }
 
 using memory_buffer = basic_memory_buffer<char>;
 using wmemory_buffer = basic_memory_buffer<wchar_t>;
 
+template <typename T, size_t SIZE, typename Allocator>
+struct is_contiguous<basic_memory_buffer<T, SIZE, Allocator>> : std::true_type {
+};
+
 /** A formatting error such as invalid format string. */
+FMT_CLASS_API
 class FMT_API format_error : public std::runtime_error {
  public:
   explicit format_error(const char* message) : std::runtime_error(message) {}
@@ -700,43 +779,134 @@ class FMT_API format_error : public std::runtime_error {
   ~format_error() FMT_NOEXCEPT FMT_OVERRIDE;
 };
 
-namespace internal {
+namespace detail {
+
+template <typename T>
+using is_signed =
+    std::integral_constant<bool, std::numeric_limits<T>::is_signed ||
+                                     std::is_same<T, int128_t>::value>;
 
 // Returns true if value is negative, false otherwise.
 // Same as `value < 0` but doesn't produce warnings if T is an unsigned type.
-template <typename T, FMT_ENABLE_IF(std::numeric_limits<T>::is_signed)>
+template <typename T, FMT_ENABLE_IF(is_signed<T>::value)>
 FMT_CONSTEXPR bool is_negative(T value) {
   return value < 0;
 }
-template <typename T, FMT_ENABLE_IF(!std::numeric_limits<T>::is_signed)>
+template <typename T, FMT_ENABLE_IF(!is_signed<T>::value)>
 FMT_CONSTEXPR bool is_negative(T) {
   return false;
 }
 
+template <typename T, FMT_ENABLE_IF(std::is_floating_point<T>::value)>
+FMT_CONSTEXPR bool is_supported_floating_point(T) {
+  return (std::is_same<T, float>::value && FMT_USE_FLOAT) ||
+         (std::is_same<T, double>::value && FMT_USE_DOUBLE) ||
+         (std::is_same<T, long double>::value && FMT_USE_LONG_DOUBLE);
+}
+
 // Smallest of uint32_t, uint64_t, uint128_t that is large enough to
-// represent all values of T.
+// represent all values of an integral type T.
 template <typename T>
-using uint32_or_64_or_128_t = conditional_t<
-    std::numeric_limits<T>::digits <= 32, uint32_t,
-    conditional_t<std::numeric_limits<T>::digits <= 64, uint64_t, uint128_t>>;
+using uint32_or_64_or_128_t =
+    conditional_t<num_bits<T>() <= 32 && !FMT_REDUCE_INT_INSTANTIATIONS,
+                  uint32_t,
+                  conditional_t<num_bits<T>() <= 64, uint64_t, uint128_t>>;
+
+// 128-bit integer type used internally
+struct FMT_EXTERN_TEMPLATE_API uint128_wrapper {
+  uint128_wrapper() = default;
+
+#if FMT_USE_INT128
+  uint128_t internal_;
+
+  uint128_wrapper(uint64_t high, uint64_t low) FMT_NOEXCEPT
+      : internal_{static_cast<uint128_t>(low) |
+                  (static_cast<uint128_t>(high) << 64)} {}
+
+  uint128_wrapper(uint128_t u) : internal_{u} {}
+
+  uint64_t high() const FMT_NOEXCEPT { return uint64_t(internal_ >> 64); }
+  uint64_t low() const FMT_NOEXCEPT { return uint64_t(internal_); }
+
+  uint128_wrapper& operator+=(uint64_t n) FMT_NOEXCEPT {
+    internal_ += n;
+    return *this;
+  }
+#else
+  uint64_t high_;
+  uint64_t low_;
+
+  uint128_wrapper(uint64_t high, uint64_t low) FMT_NOEXCEPT : high_{high},
+                                                              low_{low} {}
+
+  uint64_t high() const FMT_NOEXCEPT { return high_; }
+  uint64_t low() const FMT_NOEXCEPT { return low_; }
+
+  uint128_wrapper& operator+=(uint64_t n) FMT_NOEXCEPT {
+#  if defined(_MSC_VER) && defined(_M_X64)
+    unsigned char carry = _addcarry_u64(0, low_, n, &low_);
+    _addcarry_u64(carry, high_, 0, &high_);
+    return *this;
+#  else
+    uint64_t sum = low_ + n;
+    high_ += (sum < low_ ? 1 : 0);
+    low_ = sum;
+    return *this;
+#  endif
+  }
+#endif
+};
+
+// Table entry type for divisibility test used internally
+template <typename T> struct FMT_EXTERN_TEMPLATE_API divtest_table_entry {
+  T mod_inv;
+  T max_quotient;
+};
 
 // Static data is placed in this class template for the header-only config.
 template <typename T = void> struct FMT_EXTERN_TEMPLATE_API basic_data {
   static const uint64_t powers_of_10_64[];
   static const uint32_t zero_or_powers_of_10_32[];
   static const uint64_t zero_or_powers_of_10_64[];
-  static const uint64_t pow10_significands[];
-  static const int16_t pow10_exponents[];
-  static const char digits[];
+  static const uint64_t grisu_pow10_significands[];
+  static const int16_t grisu_pow10_exponents[];
+  static const divtest_table_entry<uint32_t> divtest_table_for_pow5_32[];
+  static const divtest_table_entry<uint64_t> divtest_table_for_pow5_64[];
+  static const uint64_t dragonbox_pow10_significands_64[];
+  static const uint128_wrapper dragonbox_pow10_significands_128[];
+  // log10(2) = 0x0.4d104d427de7fbcc...
+  static const uint64_t log10_2_significand = 0x4d104d427de7fbcc;
+#if !FMT_USE_FULL_CACHE_DRAGONBOX
+  static const uint64_t powers_of_5_64[];
+  static const uint32_t dragonbox_pow10_recovery_errors[];
+#endif
+  // GCC generates slightly better code for pairs than chars.
+  using digit_pair = char[2];
+  static const digit_pair digits[];
   static const char hex_digits[];
   static const char foreground_color[];
   static const char background_color[];
   static const char reset_color[5];
   static const wchar_t wreset_color[5];
   static const char signs[];
+  static const char left_padding_shifts[5];
+  static const char right_padding_shifts[5];
 };
 
+// Maps bsr(n) to ceil(log10(pow(2, bsr(n) + 1) - 1)).
+// This is a function instead of an array to workaround a bug in GCC10 (#1810).
+FMT_INLINE uint16_t bsr2log10(int bsr) {
+  static constexpr uint16_t data[] = {
+      1,  1,  1,  2,  2,  2,  3,  3,  3,  4,  4,  4,  4,  5,  5,  5,
+      6,  6,  6,  7,  7,  7,  7,  8,  8,  8,  9,  9,  9,  10, 10, 10,
+      10, 11, 11, 11, 12, 12, 12, 13, 13, 13, 13, 14, 14, 14, 15, 15,
+      15, 16, 16, 16, 16, 17, 17, 17, 18, 18, 18, 19, 19, 19, 19, 20};
+  return data[bsr];
+}
+
+#ifndef FMT_EXPORTED
 FMT_EXTERN template struct basic_data<void>;
+#endif
 
 // This is a struct rather than an alias to avoid shadowing warnings in gcc.
 struct data : basic_data<> {};
@@ -745,10 +915,9 @@ struct data : basic_data<> {};
 // Returns the number of decimal digits in n. Leading zeros are not counted
 // except for n == 0 in which case count_digits returns 1.
 inline int count_digits(uint64_t n) {
-  // Based on http://graphics.stanford.edu/~seander/bithacks.html#IntegerLog10
-  // and the benchmark https://github.com/localvoid/cxx-benchmark-count-digits.
-  int t = (64 - FMT_BUILTIN_CLZLL(n | 1)) * 1233 >> 12;
-  return t - (n < data::zero_or_powers_of_10_64[t]) + 1;
+  // https://github.com/fmtlib/format-benchmark/blob/master/digits10
+  auto t = bsr2log10(FMT_BUILTIN_CLZLL(n | 1) ^ 63);
+  return t - (n < data::zero_or_powers_of_10_64[t]);
 }
 #else
 // Fallback version of count_digits used when __builtin_clz is not available.
@@ -794,22 +963,37 @@ template <unsigned BITS, typename UInt> inline int count_digits(UInt n) {
   return num_digits;
 }
 
-template <> int count_digits<4>(internal::fallback_uintptr n);
+template <> int count_digits<4>(detail::fallback_uintptr n);
 
 #if FMT_GCC_VERSION || FMT_CLANG_VERSION
 #  define FMT_ALWAYS_INLINE inline __attribute__((always_inline))
+#elif FMT_MSC_VER
+#  define FMT_ALWAYS_INLINE __forceinline
 #else
-#  define FMT_ALWAYS_INLINE
+#  define FMT_ALWAYS_INLINE inline
+#endif
+
+// To suppress unnecessary security cookie checks
+#if FMT_MSC_VER && !FMT_CLANG_VERSION
+#  define FMT_SAFEBUFFERS __declspec(safebuffers)
+#else
+#  define FMT_SAFEBUFFERS
 #endif
 
 #ifdef FMT_BUILTIN_CLZ
 // Optional version of count_digits for better performance on 32-bit platforms.
 inline int count_digits(uint32_t n) {
-  int t = (32 - FMT_BUILTIN_CLZ(n | 1)) * 1233 >> 12;
-  return t - (n < data::zero_or_powers_of_10_32[t]) + 1;
+  auto t = bsr2log10(FMT_BUILTIN_CLZ(n | 1) ^ 31);
+  return t - (n < data::zero_or_powers_of_10_32[t]);
 }
 #endif
 
+template <typename Int> constexpr int digits10() FMT_NOEXCEPT {
+  return std::numeric_limits<Int>::digits10;
+}
+template <> constexpr int digits10<int128_t>() FMT_NOEXCEPT { return 38; }
+template <> constexpr int digits10<uint128_t>() FMT_NOEXCEPT { return 38; }
+
 template <typename Char> FMT_API std::string grouping_impl(locale_ref loc);
 template <typename Char> inline std::string grouping(locale_ref loc) {
   return grouping_impl<char>(loc);
@@ -834,57 +1018,60 @@ template <> inline wchar_t decimal_point(locale_ref loc) {
   return decimal_point_impl<wchar_t>(loc);
 }
 
-// Formats a decimal unsigned integer value writing into buffer.
-// add_thousands_sep is called after writing each char to add a thousands
-// separator if necessary.
-template <typename UInt, typename Char, typename F>
-inline Char* format_decimal(Char* buffer, UInt value, int num_digits,
-                            F add_thousands_sep) {
-  FMT_ASSERT(num_digits >= 0, "invalid digit count");
-  buffer += num_digits;
-  Char* end = buffer;
+// Compares two characters for equality.
+template <typename Char> bool equal2(const Char* lhs, const char* rhs) {
+  return lhs[0] == rhs[0] && lhs[1] == rhs[1];
+}
+inline bool equal2(const char* lhs, const char* rhs) {
+  return memcmp(lhs, rhs, 2) == 0;
+}
+
+// Copies two characters from src to dst.
+template <typename Char> void copy2(Char* dst, const char* src) {
+  *dst++ = static_cast<Char>(*src++);
+  *dst = static_cast<Char>(*src);
+}
+FMT_INLINE void copy2(char* dst, const char* src) { memcpy(dst, src, 2); }
+
+template <typename Iterator> struct format_decimal_result {
+  Iterator begin;
+  Iterator end;
+};
+
+// Formats a decimal unsigned integer value writing into out pointing to a
+// buffer of specified size. The caller must ensure that the buffer is large
+// enough.
+template <typename Char, typename UInt>
+inline format_decimal_result<Char*> format_decimal(Char* out, UInt value,
+                                                   int size) {
+  FMT_ASSERT(size >= count_digits(value), "invalid digit count");
+  out += size;
+  Char* end = out;
   while (value >= 100) {
     // Integer division is slow so do it for a group of two digits instead
     // of for every digit. The idea comes from the talk by Alexandrescu
     // "Three Optimization Tips for C++". See speed-test for a comparison.
-    auto index = static_cast<unsigned>((value % 100) * 2);
+    out -= 2;
+    copy2(out, data::digits[value % 100]);
     value /= 100;
-    *--buffer = static_cast<Char>(data::digits[index + 1]);
-    add_thousands_sep(buffer);
-    *--buffer = static_cast<Char>(data::digits[index]);
-    add_thousands_sep(buffer);
   }
   if (value < 10) {
-    *--buffer = static_cast<Char>('0' + value);
-    return end;
+    *--out = static_cast<Char>('0' + value);
+    return {out, end};
   }
-  auto index = static_cast<unsigned>(value * 2);
-  *--buffer = static_cast<Char>(data::digits[index + 1]);
-  add_thousands_sep(buffer);
-  *--buffer = static_cast<Char>(data::digits[index]);
-  return end;
-}
-
-template <typename Int> constexpr int digits10() noexcept {
-  return std::numeric_limits<Int>::digits10;
+  out -= 2;
+  copy2(out, data::digits[value]);
+  return {out, end};
 }
-template <> constexpr int digits10<int128_t>() noexcept { return 38; }
-template <> constexpr int digits10<uint128_t>() noexcept { return 38; }
 
-template <typename Char, typename UInt, typename Iterator, typename F>
-inline Iterator format_decimal(Iterator out, UInt value, int num_digits,
-                               F add_thousands_sep) {
-  FMT_ASSERT(num_digits >= 0, "invalid digit count");
-  // Buffer should be large enough to hold all digits (<= digits10 + 1).
-  enum { max_size = digits10<UInt>() + 1 };
-  Char buffer[2 * max_size];
-  auto end = format_decimal(buffer, value, num_digits, add_thousands_sep);
-  return internal::copy_str<Char>(buffer, end, out);
-}
-
-template <typename Char, typename It, typename UInt>
-inline It format_decimal(It out, UInt value, int num_digits) {
-  return format_decimal<Char>(out, value, num_digits, [](Char*) {});
+template <typename Char, typename UInt, typename Iterator,
+          FMT_ENABLE_IF(!std::is_pointer<remove_cvref_t<Iterator>>::value)>
+inline format_decimal_result<Iterator> format_decimal(Iterator out, UInt value,
+                                                      int size) {
+  // Buffer is large enough to hold all digits (digits10 + 1).
+  Char buffer[digits10<UInt>() + 1];
+  auto end = format_decimal(buffer, value, size).end;
+  return {out, detail::copy_str<Char>(buffer, end, out)};
 }
 
 template <unsigned BASE_BITS, typename Char, typename UInt>
@@ -902,7 +1089,7 @@ inline Char* format_uint(Char* buffer, UInt value, int num_digits,
 }
 
 template <unsigned BASE_BITS, typename Char>
-Char* format_uint(Char* buffer, internal::fallback_uintptr n, int num_digits,
+Char* format_uint(Char* buffer, detail::fallback_uintptr n, int num_digits,
                   bool = false) {
   auto char_digits = std::numeric_limits<unsigned char>::digits / 4;
   int start = (num_digits + char_digits - 1) / char_digits - 1;
@@ -925,67 +1112,52 @@ Char* format_uint(Char* buffer, internal::fallback_uintptr n, int num_digits,
 
 template <unsigned BASE_BITS, typename Char, typename It, typename UInt>
 inline It format_uint(It out, UInt value, int num_digits, bool upper = false) {
+  if (auto ptr = to_pointer<Char>(out, to_unsigned(num_digits))) {
+    format_uint<BASE_BITS>(ptr, value, num_digits, upper);
+    return out;
+  }
   // Buffer should be large enough to hold all digits (digits / BASE_BITS + 1).
   char buffer[num_bits<UInt>() / BASE_BITS + 1];
   format_uint<BASE_BITS>(buffer, value, num_digits, upper);
-  return internal::copy_str<Char>(buffer, buffer + num_digits, out);
+  return detail::copy_str<Char>(buffer, buffer + num_digits, out);
 }
 
-#ifndef _WIN32
-#  define FMT_USE_WINDOWS_H 0
-#elif !defined(FMT_USE_WINDOWS_H)
-#  define FMT_USE_WINDOWS_H 1
-#endif
-
-// Define FMT_USE_WINDOWS_H to 0 to disable use of windows.h.
-// All the functionality that relies on it will be disabled too.
-#if FMT_USE_WINDOWS_H
 // A converter from UTF-8 to UTF-16.
-// It is only provided for Windows since other systems support UTF-8 natively.
 class utf8_to_utf16 {
  private:
   wmemory_buffer buffer_;
 
  public:
   FMT_API explicit utf8_to_utf16(string_view s);
-  operator wstring_view() const { return wstring_view(&buffer_[0], size()); }
+  operator wstring_view() const { return {&buffer_[0], size()}; }
   size_t size() const { return buffer_.size() - 1; }
   const wchar_t* c_str() const { return &buffer_[0]; }
-  std::wstring str() const { return std::wstring(&buffer_[0], size()); }
+  std::wstring str() const { return {&buffer_[0], size()}; }
 };
 
-// A converter from UTF-16 to UTF-8.
-// It is only provided for Windows since other systems support UTF-8 natively.
-class utf16_to_utf8 {
- private:
-  memory_buffer buffer_;
-
- public:
-  utf16_to_utf8() {}
-  FMT_API explicit utf16_to_utf8(wstring_view s);
-  operator string_view() const { return string_view(&buffer_[0], size()); }
-  size_t size() const { return buffer_.size() - 1; }
-  const char* c_str() const { return &buffer_[0]; }
-  std::string str() const { return std::string(&buffer_[0], size()); }
-
-  // Performs conversion returning a system error code instead of
-  // throwing exception on conversion error. This method may still throw
-  // in case of memory allocation error.
-  FMT_API int convert(wstring_view s);
-};
-
-FMT_API void format_windows_error(internal::buffer<char>& out, int error_code,
-                                  string_view message) FMT_NOEXCEPT;
-#endif
-
 template <typename T = void> struct null {};
 
 // Workaround an array initialization issue in gcc 4.8.
 template <typename Char> struct fill_t {
  private:
-  Char data_[6];
+  enum { max_size = 4 };
+  Char data_[max_size];
+  unsigned char size_;
 
  public:
+  FMT_CONSTEXPR void operator=(basic_string_view<Char> s) {
+    auto size = s.size();
+    if (size > max_size) {
+      FMT_THROW(format_error("invalid fill"));
+      return;
+    }
+    for (size_t i = 0; i < size; ++i) data_[i] = s[i];
+    size_ = static_cast<unsigned char>(size);
+  }
+
+  size_t size() const { return size_; }
+  const Char* data() const { return data_; }
+
   FMT_CONSTEXPR Char& operator[](size_t index) { return data_[index]; }
   FMT_CONSTEXPR const Char& operator[](size_t index) const {
     return data_[index];
@@ -994,10 +1166,11 @@ template <typename Char> struct fill_t {
   static FMT_CONSTEXPR fill_t<Char> make() {
     auto fill = fill_t<Char>();
     fill[0] = Char(' ');
+    fill.size_ = 1;
     return fill;
   }
 };
-}  // namespace internal
+}  // namespace detail
 
 // We cannot use enum classes as bit fields because of a gcc bug
 // https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61414.
@@ -1019,7 +1192,7 @@ template <typename Char> struct basic_format_specs {
   align_t align : 4;
   sign_t sign : 3;
   bool alt : 1;  // Alternate form ('#').
-  internal::fill_t<Char> fill;
+  detail::fill_t<Char> fill;
 
   constexpr basic_format_specs()
       : width(0),
@@ -1028,12 +1201,84 @@ template <typename Char> struct basic_format_specs {
         align(align::none),
         sign(sign::none),
         alt(false),
-        fill(internal::fill_t<Char>::make()) {}
+        fill(detail::fill_t<Char>::make()) {}
 };
 
 using format_specs = basic_format_specs<char>;
 
-namespace internal {
+namespace detail {
+namespace dragonbox {
+
+// Type-specific information that Dragonbox uses.
+template <class T> struct float_info;
+
+template <> struct float_info<float> {
+  using carrier_uint = uint32_t;
+  static const int significand_bits = 23;
+  static const int exponent_bits = 8;
+  static const int min_exponent = -126;
+  static const int max_exponent = 127;
+  static const int exponent_bias = -127;
+  static const int decimal_digits = 9;
+  static const int kappa = 1;
+  static const int big_divisor = 100;
+  static const int small_divisor = 10;
+  static const int min_k = -31;
+  static const int max_k = 46;
+  static const int cache_bits = 64;
+  static const int divisibility_check_by_5_threshold = 39;
+  static const int case_fc_pm_half_lower_threshold = -1;
+  static const int case_fc_pm_half_upper_threshold = 6;
+  static const int case_fc_lower_threshold = -2;
+  static const int case_fc_upper_threshold = 6;
+  static const int case_shorter_interval_left_endpoint_lower_threshold = 2;
+  static const int case_shorter_interval_left_endpoint_upper_threshold = 3;
+  static const int shorter_interval_tie_lower_threshold = -35;
+  static const int shorter_interval_tie_upper_threshold = -35;
+  static const int max_trailing_zeros = 7;
+};
+
+template <> struct float_info<double> {
+  using carrier_uint = uint64_t;
+  static const int significand_bits = 52;
+  static const int exponent_bits = 11;
+  static const int min_exponent = -1022;
+  static const int max_exponent = 1023;
+  static const int exponent_bias = -1023;
+  static const int decimal_digits = 17;
+  static const int kappa = 2;
+  static const int big_divisor = 1000;
+  static const int small_divisor = 100;
+  static const int min_k = -292;
+  static const int max_k = 326;
+  static const int cache_bits = 128;
+  static const int divisibility_check_by_5_threshold = 86;
+  static const int case_fc_pm_half_lower_threshold = -2;
+  static const int case_fc_pm_half_upper_threshold = 9;
+  static const int case_fc_lower_threshold = -4;
+  static const int case_fc_upper_threshold = 9;
+  static const int case_shorter_interval_left_endpoint_lower_threshold = 2;
+  static const int case_shorter_interval_left_endpoint_upper_threshold = 3;
+  static const int shorter_interval_tie_lower_threshold = -77;
+  static const int shorter_interval_tie_upper_threshold = -77;
+  static const int max_trailing_zeros = 16;
+};
+
+template <typename T> struct decimal_fp {
+  using significand_type = typename float_info<T>::carrier_uint;
+  significand_type significand;
+  int exponent;
+};
+
+template <typename T> decimal_fp<T> to_decimal(T x) FMT_NOEXCEPT;
+}  // namespace dragonbox
+
+template <typename T>
+constexpr typename dragonbox::float_info<T>::carrier_uint exponent_mask() {
+  using uint_type = typename dragonbox::float_info<T>::carrier_uint;
+  return ((uint_type(1) << dragonbox::float_info<T>::exponent_bits) - 1)
+         << dragonbox::float_info<T>::significand_bits;
+}
 
 // A floating-point presentation format.
 enum class float_format : unsigned char {
@@ -1049,10 +1294,9 @@ struct float_specs {
   sign_t sign : 8;
   bool upper : 1;
   bool locale : 1;
-  bool percent : 1;
   bool binary32 : 1;
   bool use_grisu : 1;
-  bool trailing_zeros : 1;
+  bool showpoint : 1;
 };
 
 // Writes the exponent exp in the form "[+-]d{2,3}" to buffer.
@@ -1065,123 +1309,17 @@ template <typename Char, typename It> It write_exponent(int exp, It it) {
     *it++ = static_cast<Char>('+');
   }
   if (exp >= 100) {
-    const char* top = data::digits + (exp / 100) * 2;
+    const char* top = data::digits[exp / 100];
     if (exp >= 1000) *it++ = static_cast<Char>(top[0]);
     *it++ = static_cast<Char>(top[1]);
     exp %= 100;
   }
-  const char* d = data::digits + exp * 2;
+  const char* d = data::digits[exp];
   *it++ = static_cast<Char>(d[0]);
   *it++ = static_cast<Char>(d[1]);
   return it;
 }
 
-template <typename Char> class float_writer {
- private:
-  // The number is given as v = digits_ * pow(10, exp_).
-  const char* digits_;
-  int num_digits_;
-  int exp_;
-  size_t size_;
-  float_specs specs_;
-  Char decimal_point_;
-
-  template <typename It> It prettify(It it) const {
-    // pow(10, full_exp - 1) <= v <= pow(10, full_exp).
-    int full_exp = num_digits_ + exp_;
-    if (specs_.format == float_format::exp) {
-      // Insert a decimal point after the first digit and add an exponent.
-      *it++ = static_cast<Char>(*digits_);
-      int num_zeros = specs_.precision - num_digits_;
-      bool trailing_zeros = num_zeros > 0 && specs_.trailing_zeros;
-      if (num_digits_ > 1 || trailing_zeros) *it++ = decimal_point_;
-      it = copy_str<Char>(digits_ + 1, digits_ + num_digits_, it);
-      if (trailing_zeros)
-        it = std::fill_n(it, num_zeros, static_cast<Char>('0'));
-      *it++ = static_cast<Char>(specs_.upper ? 'E' : 'e');
-      return write_exponent<Char>(full_exp - 1, it);
-    }
-    if (num_digits_ <= full_exp) {
-      // 1234e7 -> 12340000000[.0+]
-      it = copy_str<Char>(digits_, digits_ + num_digits_, it);
-      it = std::fill_n(it, full_exp - num_digits_, static_cast<Char>('0'));
-      if (specs_.trailing_zeros) {
-        *it++ = decimal_point_;
-        int num_zeros = specs_.precision - full_exp;
-        if (num_zeros <= 0) {
-          if (specs_.format != float_format::fixed)
-            *it++ = static_cast<Char>('0');
-          return it;
-        }
-#ifdef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
-        if (num_zeros > 1000)
-          throw std::runtime_error("fuzz mode - avoiding excessive cpu use");
-#endif
-        it = std::fill_n(it, num_zeros, static_cast<Char>('0'));
-      }
-    } else if (full_exp > 0) {
-      // 1234e-2 -> 12.34[0+]
-      it = copy_str<Char>(digits_, digits_ + full_exp, it);
-      if (!specs_.trailing_zeros) {
-        // Remove trailing zeros.
-        int num_digits = num_digits_;
-        while (num_digits > full_exp && digits_[num_digits - 1] == '0')
-          --num_digits;
-        if (num_digits != full_exp) *it++ = decimal_point_;
-        return copy_str<Char>(digits_ + full_exp, digits_ + num_digits, it);
-      }
-      *it++ = decimal_point_;
-      it = copy_str<Char>(digits_ + full_exp, digits_ + num_digits_, it);
-      if (specs_.precision > num_digits_) {
-        // Add trailing zeros.
-        int num_zeros = specs_.precision - num_digits_;
-        it = std::fill_n(it, num_zeros, static_cast<Char>('0'));
-      }
-    } else {
-      // 1234e-6 -> 0.001234
-      *it++ = static_cast<Char>('0');
-      int num_zeros = -full_exp;
-      if (specs_.precision >= 0 && specs_.precision < num_zeros)
-        num_zeros = specs_.precision;
-      int num_digits = num_digits_;
-      if (!specs_.trailing_zeros)
-        while (num_digits > 0 && digits_[num_digits - 1] == '0') --num_digits;
-      if (num_zeros != 0 || num_digits != 0) {
-        *it++ = decimal_point_;
-        it = std::fill_n(it, num_zeros, static_cast<Char>('0'));
-        it = copy_str<Char>(digits_, digits_ + num_digits, it);
-      }
-    }
-    return it;
-  }
-
- public:
-  float_writer(const char* digits, int num_digits, int exp, float_specs specs,
-               Char decimal_point)
-      : digits_(digits),
-        num_digits_(num_digits),
-        exp_(exp),
-        specs_(specs),
-        decimal_point_(decimal_point) {
-    int full_exp = num_digits + exp - 1;
-    int precision = specs.precision > 0 ? specs.precision : 16;
-    if (specs_.format == float_format::general &&
-        !(full_exp >= -4 && full_exp < precision)) {
-      specs_.format = float_format::exp;
-    }
-    size_ = prettify(counting_iterator()).count();
-    size_ += specs.sign ? 1 : 0;
-  }
-
-  size_t size() const { return size_; }
-  size_t width() const { return size(); }
-
-  template <typename It> void operator()(It&& it) {
-    if (specs_.sign) *it++ = static_cast<Char>(data::signs[specs_.sign]);
-    it = prettify(it);
-  }
-};
-
 template <typename T>
 int format_float(T value, int precision, float_specs specs, buffer<char>& buf);
 
@@ -1191,7 +1329,7 @@ int snprintf_float(T value, int precision, float_specs specs,
                    buffer<char>& buf);
 
 template <typename T> T promote_float(T value) { return value; }
-inline double promote_float(float value) { return value; }
+inline double promote_float(float value) { return static_cast<double>(value); }
 
 template <typename Handler>
 FMT_CONSTEXPR void handle_int_type_spec(char spec, Handler&& handler) {
@@ -1211,9 +1349,15 @@ FMT_CONSTEXPR void handle_int_type_spec(char spec, Handler&& handler) {
   case 'o':
     handler.on_oct();
     break;
+#ifdef FMT_DEPRECATED_N_SPECIFIER
   case 'n':
+#endif
+  case 'L':
     handler.on_num();
     break;
+  case 'c':
+    handler.on_chr();
+    break;
   default:
     handler.on_error();
   }
@@ -1223,11 +1367,11 @@ template <typename ErrorHandler = error_handler, typename Char>
 FMT_CONSTEXPR float_specs parse_float_type_spec(
     const basic_format_specs<Char>& specs, ErrorHandler&& eh = {}) {
   auto result = float_specs();
-  result.trailing_zeros = specs.alt;
+  result.showpoint = specs.alt;
   switch (specs.type) {
   case 0:
     result.format = float_format::general;
-    result.trailing_zeros |= specs.precision != 0;
+    result.showpoint |= specs.precision > 0;
     break;
   case 'G':
     result.upper = true;
@@ -1240,28 +1384,25 @@ FMT_CONSTEXPR float_specs parse_float_type_spec(
     FMT_FALLTHROUGH;
   case 'e':
     result.format = float_format::exp;
-    result.trailing_zeros |= specs.precision != 0;
+    result.showpoint |= specs.precision != 0;
     break;
   case 'F':
     result.upper = true;
     FMT_FALLTHROUGH;
   case 'f':
     result.format = float_format::fixed;
-    result.trailing_zeros |= specs.precision != 0;
-    break;
-#if FMT_DEPRECATED_PERCENT
-  case '%':
-    result.format = float_format::fixed;
-    result.percent = true;
+    result.showpoint |= specs.precision != 0;
     break;
-#endif
   case 'A':
     result.upper = true;
     FMT_FALLTHROUGH;
   case 'a':
     result.format = float_format::hex;
     break;
+#ifdef FMT_DEPRECATED_N_SPECIFIER
   case 'n':
+#endif
+  case 'L':
     result.locale = true;
     break;
   default:
@@ -1310,6 +1451,7 @@ template <typename ErrorHandler> class int_type_checker : private ErrorHandler {
   FMT_CONSTEXPR void on_bin() {}
   FMT_CONSTEXPR void on_oct() {}
   FMT_CONSTEXPR void on_num() {}
+  FMT_CONSTEXPR void on_chr() {}
 
   FMT_CONSTEXPR void on_error() {
     ErrorHandler::on_error("invalid type specifier");
@@ -1341,386 +1483,669 @@ class cstring_type_checker : public ErrorHandler {
   FMT_CONSTEXPR void on_pointer() {}
 };
 
-template <typename Context>
-void arg_map<Context>::init(const basic_format_args<Context>& args) {
-  if (map_) return;
-  map_ = new entry[internal::to_unsigned(args.max_size())];
-  if (args.is_packed()) {
-    for (int i = 0;; ++i) {
-      internal::type arg_type = args.type(i);
-      if (arg_type == internal::none_type) return;
-      if (arg_type == internal::named_arg_type) push_back(args.values_[i]);
-    }
-  }
-  for (int i = 0, n = args.max_size(); i < n; ++i) {
-    auto type = args.args_[i].type_;
-    if (type == internal::named_arg_type) push_back(args.args_[i].value_);
-  }
+template <typename OutputIt, typename Char>
+FMT_NOINLINE OutputIt fill(OutputIt it, size_t n, const fill_t<Char>& fill) {
+  auto fill_size = fill.size();
+  if (fill_size == 1) return std::fill_n(it, n, fill[0]);
+  for (size_t i = 0; i < n; ++i) it = std::copy_n(fill.data(), fill_size, it);
+  return it;
 }
 
-template <typename Char> struct nonfinite_writer {
-  sign_t sign;
-  const char* str;
-  static constexpr size_t str_size = 3;
-
-  size_t size() const { return str_size + (sign ? 1 : 0); }
-  size_t width() const { return size(); }
-
-  template <typename It> void operator()(It&& it) const {
-    if (sign) *it++ = static_cast<Char>(data::signs[sign]);
-    it = copy_str<Char>(str, str + str_size, it);
+// Writes the output of f, padded according to format specifications in specs.
+// size: output size in code units.
+// width: output display width in (terminal) column positions.
+template <align::type align = align::left, typename OutputIt, typename Char,
+          typename F>
+inline OutputIt write_padded(OutputIt out,
+                             const basic_format_specs<Char>& specs, size_t size,
+                             size_t width, F&& f) {
+  static_assert(align == align::left || align == align::right, "");
+  unsigned spec_width = to_unsigned(specs.width);
+  size_t padding = spec_width > width ? spec_width - width : 0;
+  auto* shifts = align == align::left ? data::left_padding_shifts
+                                      : data::right_padding_shifts;
+  size_t left_padding = padding >> shifts[specs.align];
+  auto it = reserve(out, size + padding * specs.fill.size());
+  it = fill(it, left_padding, specs.fill);
+  it = f(it);
+  it = fill(it, padding - left_padding, specs.fill);
+  return base_iterator(out, it);
+}
+
+template <align::type align = align::left, typename OutputIt, typename Char,
+          typename F>
+inline OutputIt write_padded(OutputIt out,
+                             const basic_format_specs<Char>& specs, size_t size,
+                             F&& f) {
+  return write_padded<align>(out, specs, size, size, f);
+}
+
+template <typename Char, typename OutputIt>
+OutputIt write_bytes(OutputIt out, string_view bytes,
+                     const basic_format_specs<Char>& specs) {
+  using iterator = remove_reference_t<decltype(reserve(out, 0))>;
+  return write_padded(out, specs, bytes.size(), [bytes](iterator it) {
+    const char* data = bytes.data();
+    return copy_str<Char>(data, data + bytes.size(), it);
+  });
+}
+
+// Data for write_int that doesn't depend on output iterator type. It is used to
+// avoid template code bloat.
+template <typename Char> struct write_int_data {
+  size_t size;
+  size_t padding;
+
+  write_int_data(int num_digits, string_view prefix,
+                 const basic_format_specs<Char>& specs)
+      : size(prefix.size() + to_unsigned(num_digits)), padding(0) {
+    if (specs.align == align::numeric) {
+      auto width = to_unsigned(specs.width);
+      if (width > size) {
+        padding = width - size;
+        size = width;
+      }
+    } else if (specs.precision > num_digits) {
+      size = prefix.size() + to_unsigned(specs.precision);
+      padding = to_unsigned(specs.precision - num_digits);
+    }
   }
 };
 
-// This template provides operations for formatting and writing data into a
-// character range.
-template <typename Range> class basic_writer {
- public:
-  using char_type = typename Range::value_type;
-  using iterator = typename Range::iterator;
-  using format_specs = basic_format_specs<char_type>;
-
- private:
-  iterator out_;  // Output iterator.
-  locale_ref locale_;
-
-  // Attempts to reserve space for n extra characters in the output range.
-  // Returns a pointer to the reserved range or a reference to out_.
-  auto reserve(std::size_t n) -> decltype(internal::reserve(out_, n)) {
-    return internal::reserve(out_, n);
+// Writes an integer in the format
+//   <left-padding><prefix><numeric-padding><digits><right-padding>
+// where <digits> are written by f(it).
+template <typename OutputIt, typename Char, typename F>
+OutputIt write_int(OutputIt out, int num_digits, string_view prefix,
+                   const basic_format_specs<Char>& specs, F f) {
+  auto data = write_int_data<Char>(num_digits, prefix, specs);
+  using iterator = remove_reference_t<decltype(reserve(out, 0))>;
+  return write_padded<align::right>(out, specs, data.size, [=](iterator it) {
+    if (prefix.size() != 0)
+      it = copy_str<Char>(prefix.begin(), prefix.end(), it);
+    it = std::fill_n(it, data.padding, static_cast<Char>('0'));
+    return f(it);
+  });
+}
+
+template <typename StrChar, typename Char, typename OutputIt>
+OutputIt write(OutputIt out, basic_string_view<StrChar> s,
+               const basic_format_specs<Char>& specs) {
+  auto data = s.data();
+  auto size = s.size();
+  if (specs.precision >= 0 && to_unsigned(specs.precision) < size)
+    size = code_point_index(s, to_unsigned(specs.precision));
+  auto width = specs.width != 0
+                   ? count_code_points(basic_string_view<StrChar>(data, size))
+                   : 0;
+  using iterator = remove_reference_t<decltype(reserve(out, 0))>;
+  return write_padded(out, specs, size, width, [=](iterator it) {
+    return copy_str<Char>(data, data + size, it);
+  });
+}
+
+// The handle_int_type_spec handler that writes an integer.
+template <typename OutputIt, typename Char, typename UInt> struct int_writer {
+  OutputIt out;
+  locale_ref locale;
+  const basic_format_specs<Char>& specs;
+  UInt abs_value;
+  char prefix[4];
+  unsigned prefix_size;
+
+  using iterator =
+      remove_reference_t<decltype(reserve(std::declval<OutputIt&>(), 0))>;
+
+  string_view get_prefix() const { return string_view(prefix, prefix_size); }
+
+  template <typename Int>
+  int_writer(OutputIt output, locale_ref loc, Int value,
+             const basic_format_specs<Char>& s)
+      : out(output),
+        locale(loc),
+        specs(s),
+        abs_value(static_cast<UInt>(value)),
+        prefix_size(0) {
+    static_assert(std::is_same<uint32_or_64_or_128_t<Int>, UInt>::value, "");
+    if (is_negative(value)) {
+      prefix[0] = '-';
+      ++prefix_size;
+      abs_value = 0 - abs_value;
+    } else if (specs.sign != sign::none && specs.sign != sign::minus) {
+      prefix[0] = specs.sign == sign::plus ? '+' : ' ';
+      ++prefix_size;
+    }
   }
 
-  template <typename F> struct padded_int_writer {
-    size_t size_;
-    string_view prefix;
-    char_type fill;
-    std::size_t padding;
-    F f;
-
-    size_t size() const { return size_; }
-    size_t width() const { return size_; }
+  void on_dec() {
+    auto num_digits = count_digits(abs_value);
+    out = write_int(
+        out, num_digits, get_prefix(), specs, [this, num_digits](iterator it) {
+          return format_decimal<Char>(it, abs_value, num_digits).end;
+        });
+  }
 
-    template <typename It> void operator()(It&& it) const {
-      if (prefix.size() != 0)
-        it = copy_str<char_type>(prefix.begin(), prefix.end(), it);
-      it = std::fill_n(it, padding, fill);
-      f(it);
+  void on_hex() {
+    if (specs.alt) {
+      prefix[prefix_size++] = '0';
+      prefix[prefix_size++] = specs.type;
     }
-  };
-
-  // Writes an integer in the format
-  //   <left-padding><prefix><numeric-padding><digits><right-padding>
-  // where <digits> are written by f(it).
-  template <typename F>
-  void write_int(int num_digits, string_view prefix, format_specs specs, F f) {
-    std::size_t size = prefix.size() + to_unsigned(num_digits);
-    char_type fill = specs.fill[0];
-    std::size_t padding = 0;
-    if (specs.align == align::numeric) {
-      auto unsiged_width = to_unsigned(specs.width);
-      if (unsiged_width > size) {
-        padding = unsiged_width - size;
-        size = unsiged_width;
-      }
-    } else if (specs.precision > num_digits) {
-      size = prefix.size() + to_unsigned(specs.precision);
-      padding = to_unsigned(specs.precision - num_digits);
-      fill = static_cast<char_type>('0');
+    int num_digits = count_digits<4>(abs_value);
+    out = write_int(out, num_digits, get_prefix(), specs,
+                    [this, num_digits](iterator it) {
+                      return format_uint<4, Char>(it, abs_value, num_digits,
+                                                  specs.type != 'x');
+                    });
+  }
+
+  void on_bin() {
+    if (specs.alt) {
+      prefix[prefix_size++] = '0';
+      prefix[prefix_size++] = static_cast<char>(specs.type);
+    }
+    int num_digits = count_digits<1>(abs_value);
+    out = write_int(out, num_digits, get_prefix(), specs,
+                    [this, num_digits](iterator it) {
+                      return format_uint<1, Char>(it, abs_value, num_digits);
+                    });
+  }
+
+  void on_oct() {
+    int num_digits = count_digits<3>(abs_value);
+    if (specs.alt && specs.precision <= num_digits && abs_value != 0) {
+      // Octal prefix '0' is counted as a digit, so only add it if precision
+      // is not greater than the number of digits.
+      prefix[prefix_size++] = '0';
     }
-    if (specs.align == align::none) specs.align = align::right;
-    write_padded(specs, padded_int_writer<F>{size, prefix, fill, padding, f});
+    out = write_int(out, num_digits, get_prefix(), specs,
+                    [this, num_digits](iterator it) {
+                      return format_uint<3, Char>(it, abs_value, num_digits);
+                    });
   }
 
-  // Writes a decimal integer.
-  template <typename Int> void write_decimal(Int value) {
-    auto abs_value = static_cast<uint32_or_64_or_128_t<Int>>(value);
-    bool negative = is_negative(value);
-    // Don't do -abs_value since it trips unsigned-integer-overflow sanitizer.
-    if (negative) abs_value = ~abs_value + 1;
+  enum { sep_size = 1 };
+
+  void on_num() {
+    std::string groups = grouping<Char>(locale);
+    if (groups.empty()) return on_dec();
+    auto sep = thousands_sep<Char>(locale);
+    if (!sep) return on_dec();
     int num_digits = count_digits(abs_value);
-    auto&& it = reserve((negative ? 1 : 0) + static_cast<size_t>(num_digits));
-    if (negative) *it++ = static_cast<char_type>('-');
-    it = format_decimal<char_type>(it, abs_value, num_digits);
-  }
-
-  // The handle_int_type_spec handler that writes an integer.
-  template <typename Int, typename Specs> struct int_writer {
-    using unsigned_type = uint32_or_64_or_128_t<Int>;
-
-    basic_writer<Range>& writer;
-    const Specs& specs;
-    unsigned_type abs_value;
-    char prefix[4];
-    unsigned prefix_size;
-
-    string_view get_prefix() const { return string_view(prefix, prefix_size); }
-
-    int_writer(basic_writer<Range>& w, Int value, const Specs& s)
-        : writer(w),
-          specs(s),
-          abs_value(static_cast<unsigned_type>(value)),
-          prefix_size(0) {
-      if (is_negative(value)) {
-        prefix[0] = '-';
-        ++prefix_size;
-        abs_value = 0 - abs_value;
-      } else if (specs.sign != sign::none && specs.sign != sign::minus) {
-        prefix[0] = specs.sign == sign::plus ? '+' : ' ';
-        ++prefix_size;
+    int size = num_digits, n = num_digits;
+    std::string::const_iterator group = groups.cbegin();
+    while (group != groups.cend() && n > *group && *group > 0 &&
+           *group != max_value<char>()) {
+      size += sep_size;
+      n -= *group;
+      ++group;
+    }
+    if (group == groups.cend()) size += sep_size * ((n - 1) / groups.back());
+    char digits[40];
+    format_decimal(digits, abs_value, num_digits);
+    basic_memory_buffer<Char> buffer;
+    size += static_cast<int>(prefix_size);
+    const auto usize = to_unsigned(size);
+    buffer.resize(usize);
+    basic_string_view<Char> s(&sep, sep_size);
+    // Index of a decimal digit with the least significant digit having index 0.
+    int digit_index = 0;
+    group = groups.cbegin();
+    auto p = buffer.data() + size - 1;
+    for (int i = num_digits - 1; i > 0; --i) {
+      *p-- = static_cast<Char>(digits[i]);
+      if (*group <= 0 || ++digit_index % *group != 0 ||
+          *group == max_value<char>())
+        continue;
+      if (group + 1 != groups.cend()) {
+        digit_index = 0;
+        ++group;
       }
+      std::uninitialized_copy(s.data(), s.data() + s.size(),
+                              make_checked(p, s.size()));
+      p -= s.size();
     }
+    *p-- = static_cast<Char>(*digits);
+    if (prefix_size != 0) *p = static_cast<Char>('-');
+    auto data = buffer.data();
+    out = write_padded<align::right>(
+        out, specs, usize, usize,
+        [=](iterator it) { return copy_str<Char>(data, data + size, it); });
+  }
 
-    struct dec_writer {
-      unsigned_type abs_value;
-      int num_digits;
+  void on_chr() { *out++ = static_cast<Char>(abs_value); }
 
-      template <typename It> void operator()(It&& it) const {
-        it = internal::format_decimal<char_type>(it, abs_value, num_digits);
-      }
-    };
+  FMT_NORETURN void on_error() {
+    FMT_THROW(format_error("invalid type specifier"));
+  }
+};
 
-    void on_dec() {
-      int num_digits = count_digits(abs_value);
-      writer.write_int(num_digits, get_prefix(), specs,
-                       dec_writer{abs_value, num_digits});
-    }
+template <typename Char, typename OutputIt>
+OutputIt write_nonfinite(OutputIt out, bool isinf,
+                         const basic_format_specs<Char>& specs,
+                         const float_specs& fspecs) {
+  auto str =
+      isinf ? (fspecs.upper ? "INF" : "inf") : (fspecs.upper ? "NAN" : "nan");
+  constexpr size_t str_size = 3;
+  auto sign = fspecs.sign;
+  auto size = str_size + (sign ? 1 : 0);
+  using iterator = remove_reference_t<decltype(reserve(out, 0))>;
+  return write_padded(out, specs, size, [=](iterator it) {
+    if (sign) *it++ = static_cast<Char>(data::signs[sign]);
+    return copy_str<Char>(str, str + str_size, it);
+  });
+}
 
-    struct hex_writer {
-      int_writer& self;
-      int num_digits;
+// A decimal floating-point number significand * pow(10, exp).
+struct big_decimal_fp {
+  const char* significand;
+  int significand_size;
+  int exponent;
+};
 
-      template <typename It> void operator()(It&& it) const {
-        it = format_uint<4, char_type>(it, self.abs_value, num_digits,
-                                       self.specs.type != 'x');
-      }
-    };
+inline int get_significand_size(const big_decimal_fp& fp) {
+  return fp.significand_size;
+}
+template <typename T>
+inline int get_significand_size(const dragonbox::decimal_fp<T>& fp) {
+  return count_digits(fp.significand);
+}
+
+template <typename Char, typename OutputIt>
+inline OutputIt write_significand(OutputIt out, const char* significand,
+                                  int& significand_size) {
+  return copy_str<Char>(significand, significand + significand_size, out);
+}
+template <typename Char, typename OutputIt, typename UInt>
+inline OutputIt write_significand(OutputIt out, UInt significand,
+                                  int significand_size) {
+  return format_decimal<Char>(out, significand, significand_size).end;
+}
+
+template <typename Char, typename UInt,
+          FMT_ENABLE_IF(std::is_integral<UInt>::value)>
+inline Char* write_significand(Char* out, UInt significand,
+                               int significand_size, int integral_size,
+                               Char decimal_point) {
+  if (!decimal_point)
+    return format_decimal(out, significand, significand_size).end;
+  auto end = format_decimal(out + 1, significand, significand_size).end;
+  if (integral_size == 1)
+    out[0] = out[1];
+  else
+    std::copy_n(out + 1, integral_size, out);
+  out[integral_size] = decimal_point;
+  return end;
+}
 
-    void on_hex() {
-      if (specs.alt) {
-        prefix[prefix_size++] = '0';
-        prefix[prefix_size++] = specs.type;
-      }
-      int num_digits = count_digits<4>(abs_value);
-      writer.write_int(num_digits, get_prefix(), specs,
-                       hex_writer{*this, num_digits});
+template <typename OutputIt, typename UInt, typename Char,
+          FMT_ENABLE_IF(!std::is_pointer<remove_cvref_t<OutputIt>>::value)>
+inline OutputIt write_significand(OutputIt out, UInt significand,
+                                  int significand_size, int integral_size,
+                                  Char decimal_point) {
+  // Buffer is large enough to hold digits (digits10 + 1) and a decimal point.
+  Char buffer[digits10<UInt>() + 2];
+  auto end = write_significand(buffer, significand, significand_size,
+                               integral_size, decimal_point);
+  return detail::copy_str<Char>(buffer, end, out);
+}
+
+template <typename OutputIt, typename Char>
+inline OutputIt write_significand(OutputIt out, const char* significand,
+                                  int significand_size, int integral_size,
+                                  Char decimal_point) {
+  out = detail::copy_str<Char>(significand, significand + integral_size, out);
+  if (!decimal_point) return out;
+  *out++ = decimal_point;
+  return detail::copy_str<Char>(significand + integral_size,
+                                significand + significand_size, out);
+}
+
+template <typename OutputIt, typename DecimalFP, typename Char>
+OutputIt write_float(OutputIt out, const DecimalFP& fp,
+                     const basic_format_specs<Char>& specs, float_specs fspecs,
+                     Char decimal_point) {
+  auto significand = fp.significand;
+  int significand_size = get_significand_size(fp);
+  static const Char zero = static_cast<Char>('0');
+  auto sign = fspecs.sign;
+  size_t size = to_unsigned(significand_size) + (sign ? 1 : 0);
+  using iterator = remove_reference_t<decltype(reserve(out, 0))>;
+
+  int output_exp = fp.exponent + significand_size - 1;
+  auto use_exp_format = [=]() {
+    if (fspecs.format == float_format::exp) return true;
+    if (fspecs.format != float_format::general) return false;
+    // Use the fixed notation if the exponent is in [exp_lower, exp_upper),
+    // e.g. 0.0001 instead of 1e-04. Otherwise use the exponent notation.
+    const int exp_lower = -4, exp_upper = 16;
+    return output_exp < exp_lower ||
+           output_exp >= (fspecs.precision > 0 ? fspecs.precision : exp_upper);
+  };
+  if (use_exp_format()) {
+    int num_zeros = 0;
+    if (fspecs.showpoint) {
+      num_zeros = (std::max)(fspecs.precision - significand_size, 0);
+      size += to_unsigned(num_zeros);
+    } else if (significand_size == 1) {
+      decimal_point = Char();
+    }
+    auto abs_output_exp = output_exp >= 0 ? output_exp : -output_exp;
+    int exp_digits = 2;
+    if (abs_output_exp >= 100) exp_digits = abs_output_exp >= 1000 ? 4 : 3;
+
+    size += to_unsigned((decimal_point ? 1 : 0) + 2 + exp_digits);
+    char exp_char = fspecs.upper ? 'E' : 'e';
+    auto write = [=](iterator it) {
+      if (sign) *it++ = static_cast<Char>(data::signs[sign]);
+      // Insert a decimal point after the first digit and add an exponent.
+      it = write_significand(it, significand, significand_size, 1,
+                             decimal_point);
+      if (num_zeros > 0) it = std::fill_n(it, num_zeros, zero);
+      *it++ = static_cast<Char>(exp_char);
+      return write_exponent<Char>(output_exp, it);
+    };
+    return specs.width > 0 ? write_padded<align::right>(out, specs, size, write)
+                           : base_iterator(out, write(reserve(out, size)));
+  }
+
+  int exp = fp.exponent + significand_size;
+  if (fp.exponent >= 0) {
+    // 1234e5 -> 123400000[.0+]
+    size += to_unsigned(fp.exponent);
+    int num_zeros = fspecs.precision - exp;
+#ifdef FMT_FUZZ
+    if (num_zeros > 5000)
+      throw std::runtime_error("fuzz mode - avoiding excessive cpu use");
+#endif
+    if (fspecs.showpoint) {
+      if (num_zeros <= 0 && fspecs.format != float_format::fixed) num_zeros = 1;
+      if (num_zeros > 0) size += to_unsigned(num_zeros);
     }
+    return write_padded<align::right>(out, specs, size, [&](iterator it) {
+      if (sign) *it++ = static_cast<Char>(data::signs[sign]);
+      it = write_significand<Char>(it, significand, significand_size);
+      it = std::fill_n(it, fp.exponent, zero);
+      if (!fspecs.showpoint) return it;
+      *it++ = decimal_point;
+      return num_zeros > 0 ? std::fill_n(it, num_zeros, zero) : it;
+    });
+  } else if (exp > 0) {
+    // 1234e-2 -> 12.34[0+]
+    int num_zeros = fspecs.showpoint ? fspecs.precision - significand_size : 0;
+    size += 1 + to_unsigned(num_zeros > 0 ? num_zeros : 0);
+    return write_padded<align::right>(out, specs, size, [&](iterator it) {
+      if (sign) *it++ = static_cast<Char>(data::signs[sign]);
+      it = write_significand(it, significand, significand_size, exp,
+                             decimal_point);
+      return num_zeros > 0 ? std::fill_n(it, num_zeros, zero) : it;
+    });
+  }
+  // 1234e-6 -> 0.001234
+  int num_zeros = -exp;
+  if (significand_size == 0 && fspecs.precision >= 0 &&
+      fspecs.precision < num_zeros) {
+    num_zeros = fspecs.precision;
+  }
+  size += 2 + to_unsigned(num_zeros);
+  return write_padded<align::right>(out, specs, size, [&](iterator it) {
+    if (sign) *it++ = static_cast<Char>(data::signs[sign]);
+    *it++ = zero;
+    if (num_zeros == 0 && significand_size == 0 && !fspecs.showpoint) return it;
+    *it++ = decimal_point;
+    it = std::fill_n(it, num_zeros, zero);
+    return write_significand<Char>(it, significand, significand_size);
+  });
+}
+
+template <typename Char, typename OutputIt, typename T,
+          FMT_ENABLE_IF(std::is_floating_point<T>::value)>
+OutputIt write(OutputIt out, T value, basic_format_specs<Char> specs,
+               locale_ref loc = {}) {
+  if (const_check(!is_supported_floating_point(value))) return out;
+  float_specs fspecs = parse_float_type_spec(specs);
+  fspecs.sign = specs.sign;
+  if (std::signbit(value)) {  // value < 0 is false for NaN so use signbit.
+    fspecs.sign = sign::minus;
+    value = -value;
+  } else if (fspecs.sign == sign::minus) {
+    fspecs.sign = sign::none;
+  }
+
+  if (!std::isfinite(value))
+    return write_nonfinite(out, std::isinf(value), specs, fspecs);
+
+  if (specs.align == align::numeric && fspecs.sign) {
+    auto it = reserve(out, 1);
+    *it++ = static_cast<Char>(data::signs[fspecs.sign]);
+    out = base_iterator(out, it);
+    fspecs.sign = sign::none;
+    if (specs.width != 0) --specs.width;
+  }
+
+  memory_buffer buffer;
+  if (fspecs.format == float_format::hex) {
+    if (fspecs.sign) buffer.push_back(data::signs[fspecs.sign]);
+    snprintf_float(promote_float(value), specs.precision, fspecs, buffer);
+    return write_bytes(out, {buffer.data(), buffer.size()}, specs);
+  }
+  int precision = specs.precision >= 0 || !specs.type ? specs.precision : 6;
+  if (fspecs.format == float_format::exp) {
+    if (precision == max_value<int>())
+      FMT_THROW(format_error("number is too big"));
+    else
+      ++precision;
+  }
+  if (const_check(std::is_same<T, float>())) fspecs.binary32 = true;
+  fspecs.use_grisu = is_fast_float<T>();
+  int exp = format_float(promote_float(value), precision, fspecs, buffer);
+  fspecs.precision = precision;
+  Char point =
+      fspecs.locale ? decimal_point<Char>(loc) : static_cast<Char>('.');
+  auto fp = big_decimal_fp{buffer.data(), static_cast<int>(buffer.size()), exp};
+  return write_float(out, fp, specs, fspecs, point);
+}
 
-    template <int BITS> struct bin_writer {
-      unsigned_type abs_value;
-      int num_digits;
+template <typename Char, typename OutputIt, typename T,
+          FMT_ENABLE_IF(is_fast_float<T>::value)>
+OutputIt write(OutputIt out, T value) {
+  if (const_check(!is_supported_floating_point(value))) return out;
 
-      template <typename It> void operator()(It&& it) const {
-        it = format_uint<BITS, char_type>(it, abs_value, num_digits);
-      }
-    };
+  using floaty = conditional_t<std::is_same<T, long double>::value, double, T>;
+  using uint_type = typename dragonbox::float_info<floaty>::carrier_uint;
+  auto bits = bit_cast<uint>(value);
 
-    void on_bin() {
-      if (specs.alt) {
-        prefix[prefix_size++] = '0';
-        prefix[prefix_size++] = static_cast<char>(specs.type);
-      }
-      int num_digits = count_digits<1>(abs_value);
-      writer.write_int(num_digits, get_prefix(), specs,
-                       bin_writer<1>{abs_value, num_digits});
-    }
+  auto fspecs = float_specs();
+  auto sign_bit = bits & (uint_type(1) << (num_bits<uint_type>() - 1));
+  if (sign_bit != 0) {
+    fspecs.sign = sign::minus;
+    value = -value;
+  }
 
-    void on_oct() {
-      int num_digits = count_digits<3>(abs_value);
-      if (specs.alt && specs.precision <= num_digits && abs_value != 0) {
-        // Octal prefix '0' is counted as a digit, so only add it if precision
-        // is not greater than the number of digits.
-        prefix[prefix_size++] = '0';
-      }
-      writer.write_int(num_digits, get_prefix(), specs,
-                       bin_writer<3>{abs_value, num_digits});
-    }
+  static const auto specs = basic_format_specs<Char>();
+  uint_type mask = exponent_mask<floaty>();
+  if ((bits & mask) == mask)
+    return write_nonfinite(out, std::isinf(value), specs, fspecs);
 
-    enum { sep_size = 1 };
-
-    struct num_writer {
-      unsigned_type abs_value;
-      int size;
-      const std::string& groups;
-      char_type sep;
-
-      template <typename It> void operator()(It&& it) const {
-        basic_string_view<char_type> s(&sep, sep_size);
-        // Index of a decimal digit with the least significant digit having
-        // index 0.
-        int digit_index = 0;
-        std::string::const_iterator group = groups.cbegin();
-        it = format_decimal<char_type>(
-            it, abs_value, size,
-            [this, s, &group, &digit_index](char_type*& buffer) {
-              if (*group <= 0 || ++digit_index % *group != 0 ||
-                  *group == max_value<char>())
-                return;
-              if (group + 1 != groups.cend()) {
-                digit_index = 0;
-                ++group;
-              }
-              buffer -= s.size();
-              std::uninitialized_copy(s.data(), s.data() + s.size(),
-                                      make_checked(buffer, s.size()));
-            });
-      }
-    };
+  auto dec = dragonbox::to_decimal(static_cast<floaty>(value));
+  return write_float(out, dec, specs, fspecs, static_cast<Char>('.'));
+}
 
-    void on_num() {
-      std::string groups = grouping<char_type>(writer.locale_);
-      if (groups.empty()) return on_dec();
-      auto sep = thousands_sep<char_type>(writer.locale_);
-      if (!sep) return on_dec();
-      int num_digits = count_digits(abs_value);
-      int size = num_digits;
-      std::string::const_iterator group = groups.cbegin();
-      while (group != groups.cend() && num_digits > *group && *group > 0 &&
-             *group != max_value<char>()) {
-        size += sep_size;
-        num_digits -= *group;
-        ++group;
-      }
-      if (group == groups.cend())
-        size += sep_size * ((num_digits - 1) / groups.back());
-      writer.write_int(size, get_prefix(), specs,
-                       num_writer{abs_value, size, groups, sep});
-    }
+template <typename Char, typename OutputIt, typename T,
+          FMT_ENABLE_IF(std::is_floating_point<T>::value &&
+                        !is_fast_float<T>::value)>
+inline OutputIt write(OutputIt out, T value) {
+  return write(out, value, basic_format_specs<Char>());
+}
 
-    FMT_NORETURN void on_error() {
-      FMT_THROW(format_error("invalid type specifier"));
-    }
+template <typename Char, typename OutputIt>
+OutputIt write_char(OutputIt out, Char value,
+                    const basic_format_specs<Char>& specs) {
+  using iterator = remove_reference_t<decltype(reserve(out, 0))>;
+  return write_padded(out, specs, 1, [=](iterator it) {
+    *it++ = value;
+    return it;
+  });
+}
+
+template <typename Char, typename OutputIt, typename UIntPtr>
+OutputIt write_ptr(OutputIt out, UIntPtr value,
+                   const basic_format_specs<Char>* specs) {
+  int num_digits = count_digits<4>(value);
+  auto size = to_unsigned(num_digits) + size_t(2);
+  using iterator = remove_reference_t<decltype(reserve(out, 0))>;
+  auto write = [=](iterator it) {
+    *it++ = static_cast<Char>('0');
+    *it++ = static_cast<Char>('x');
+    return format_uint<4, Char>(it, value, num_digits);
   };
+  return specs ? write_padded<align::right>(out, *specs, size, write)
+               : base_iterator(out, write(reserve(out, size)));
+}
 
-  template <typename Char> struct str_writer {
-    const Char* s;
-    size_t size_;
+template <typename T> struct is_integral : std::is_integral<T> {};
+template <> struct is_integral<int128_t> : std::true_type {};
+template <> struct is_integral<uint128_t> : std::true_type {};
 
-    size_t size() const { return size_; }
-    size_t width() const {
-      return count_code_points(basic_string_view<Char>(s, size_));
-    }
+template <typename Char, typename OutputIt>
+OutputIt write(OutputIt out, monostate) {
+  FMT_ASSERT(false, "");
+  return out;
+}
 
-    template <typename It> void operator()(It&& it) const {
-      it = copy_str<char_type>(s, s + size_, it);
-    }
-  };
+template <typename Char, typename OutputIt,
+          FMT_ENABLE_IF(!std::is_same<Char, char>::value)>
+OutputIt write(OutputIt out, string_view value) {
+  auto it = reserve(out, value.size());
+  it = copy_str<Char>(value.begin(), value.end(), it);
+  return base_iterator(out, it);
+}
+
+template <typename Char, typename OutputIt>
+OutputIt write(OutputIt out, basic_string_view<Char> value) {
+  auto it = reserve(out, value.size());
+  it = std::copy(value.begin(), value.end(), it);
+  return base_iterator(out, it);
+}
 
-  template <typename UIntPtr> struct pointer_writer {
-    UIntPtr value;
-    int num_digits;
+template <typename Char>
+buffer_appender<Char> write(buffer_appender<Char> out,
+                            basic_string_view<Char> value) {
+  get_container(out).append(value.begin(), value.end());
+  return out;
+}
+
+template <typename Char, typename OutputIt, typename T,
+          FMT_ENABLE_IF(is_integral<T>::value &&
+                        !std::is_same<T, bool>::value &&
+                        !std::is_same<T, Char>::value)>
+OutputIt write(OutputIt out, T value) {
+  auto abs_value = static_cast<uint32_or_64_or_128_t<T>>(value);
+  bool negative = is_negative(value);
+  // Don't do -abs_value since it trips unsigned-integer-overflow sanitizer.
+  if (negative) abs_value = ~abs_value + 1;
+  int num_digits = count_digits(abs_value);
+  auto size = (negative ? 1 : 0) + static_cast<size_t>(num_digits);
+  auto it = reserve(out, size);
+  if (auto ptr = to_pointer<Char>(it, size)) {
+    if (negative) *ptr++ = static_cast<Char>('-');
+    format_decimal<Char>(ptr, abs_value, num_digits);
+    return out;
+  }
+  if (negative) *it++ = static_cast<Char>('-');
+  it = format_decimal<Char>(it, abs_value, num_digits).end;
+  return base_iterator(out, it);
+}
 
-    size_t size() const { return to_unsigned(num_digits) + 2; }
-    size_t width() const { return size(); }
+template <typename Char, typename OutputIt>
+OutputIt write(OutputIt out, bool value) {
+  return write<Char>(out, string_view(value ? "true" : "false"));
+}
 
-    template <typename It> void operator()(It&& it) const {
-      *it++ = static_cast<char_type>('0');
-      *it++ = static_cast<char_type>('x');
-      it = format_uint<4, char_type>(it, value, num_digits);
-    }
-  };
+template <typename Char, typename OutputIt>
+OutputIt write(OutputIt out, Char value) {
+  auto it = reserve(out, 1);
+  *it++ = value;
+  return base_iterator(out, it);
+}
 
- public:
-  explicit basic_writer(Range out, locale_ref loc = locale_ref())
-      : out_(out.begin()), locale_(loc) {}
-
-  iterator out() const { return out_; }
-
-  // Writes a value in the format
-  //   <left-padding><value><right-padding>
-  // where <value> is written by f(it).
-  template <typename F> void write_padded(const format_specs& specs, F&& f) {
-    // User-perceived width (in code points).
-    unsigned width = to_unsigned(specs.width);
-    size_t size = f.size();  // The number of code units.
-    size_t num_code_points = width != 0 ? f.width() : size;
-    if (width <= num_code_points) return f(reserve(size));
-    auto&& it = reserve(width + (size - num_code_points));
-    char_type fill = specs.fill[0];
-    std::size_t padding = width - num_code_points;
-    if (specs.align == align::right) {
-      it = std::fill_n(it, padding, fill);
-      f(it);
-    } else if (specs.align == align::center) {
-      std::size_t left_padding = padding / 2;
-      it = std::fill_n(it, left_padding, fill);
-      f(it);
-      it = std::fill_n(it, padding - left_padding, fill);
-    } else {
-      f(it);
-      it = std::fill_n(it, padding, fill);
-    }
+template <typename Char, typename OutputIt>
+OutputIt write(OutputIt out, const Char* value) {
+  if (!value) {
+    FMT_THROW(format_error("string pointer is null"));
+  } else {
+    auto length = std::char_traits<Char>::length(value);
+    out = write(out, basic_string_view<Char>(value, length));
   }
+  return out;
+}
 
-  void write(int value) { write_decimal(value); }
-  void write(long value) { write_decimal(value); }
-  void write(long long value) { write_decimal(value); }
+template <typename Char, typename OutputIt>
+OutputIt write(OutputIt out, const void* value) {
+  return write_ptr<Char>(out, to_uintptr(value), nullptr);
+}
 
-  void write(unsigned value) { write_decimal(value); }
-  void write(unsigned long value) { write_decimal(value); }
-  void write(unsigned long long value) { write_decimal(value); }
+template <typename Char, typename OutputIt, typename T>
+auto write(OutputIt out, const T& value) -> typename std::enable_if<
+    mapped_type_constant<T, basic_format_context<OutputIt, Char>>::value ==
+        type::custom_type,
+    OutputIt>::type {
+  using context_type = basic_format_context<OutputIt, Char>;
+  using formatter_type =
+      conditional_t<has_formatter<T, context_type>::value,
+                    typename context_type::template formatter_type<T>,
+                    fallback_formatter<T, Char>>;
+  context_type ctx(out, {}, {});
+  return formatter_type().format(value, ctx);
+}
 
-#if FMT_USE_INT128
-  void write(int128_t value) { write_decimal(value); }
-  void write(uint128_t value) { write_decimal(value); }
-#endif
+// An argument visitor that formats the argument and writes it via the output
+// iterator. It's a class and not a generic lambda for compatibility with C++11.
+template <typename OutputIt, typename Char> struct default_arg_formatter {
+  using context = basic_format_context<OutputIt, Char>;
 
-  template <typename T, typename Spec>
-  void write_int(T value, const Spec& spec) {
-    handle_int_type_spec(spec.type, int_writer<T, Spec>(*this, value, spec));
+  OutputIt out;
+  basic_format_args<context> args;
+  locale_ref loc;
+
+  template <typename T> OutputIt operator()(T value) {
+    return write<Char>(out, value);
   }
 
-  template <typename T, FMT_ENABLE_IF(std::is_floating_point<T>::value)>
-  void write(T value, format_specs specs = {}) {
-    float_specs fspecs = parse_float_type_spec(specs);
-    fspecs.sign = specs.sign;
-    if (std::signbit(value)) {  // value < 0 is false for NaN so use signbit.
-      fspecs.sign = sign::minus;
-      value = -value;
-    } else if (fspecs.sign == sign::minus) {
-      fspecs.sign = sign::none;
-    }
+  OutputIt operator()(typename basic_format_arg<context>::handle handle) {
+    basic_format_parse_context<Char> parse_ctx({});
+    basic_format_context<OutputIt, Char> format_ctx(out, args, loc);
+    handle.format(parse_ctx, format_ctx);
+    return format_ctx.out();
+  }
+};
 
-    if (!std::isfinite(value)) {
-      auto str = std::isinf(value) ? (fspecs.upper ? "INF" : "inf")
-                                   : (fspecs.upper ? "NAN" : "nan");
-      return write_padded(specs, nonfinite_writer<char_type>{fspecs.sign, str});
-    }
+template <typename OutputIt, typename Char,
+          typename ErrorHandler = error_handler>
+class arg_formatter_base {
+ public:
+  using iterator = OutputIt;
+  using char_type = Char;
+  using format_specs = basic_format_specs<Char>;
 
-    if (specs.align == align::none) {
-      specs.align = align::right;
-    } else if (specs.align == align::numeric) {
-      if (fspecs.sign) {
-        auto&& it = reserve(1);
-        *it++ = static_cast<char_type>(data::signs[fspecs.sign]);
-        fspecs.sign = sign::none;
-        if (specs.width != 0) --specs.width;
-      }
-      specs.align = align::right;
-    }
+ private:
+  iterator out_;
+  locale_ref locale_;
+  format_specs* specs_;
 
-    memory_buffer buffer;
-    if (fspecs.format == float_format::hex) {
-      if (fspecs.sign) buffer.push_back(data::signs[fspecs.sign]);
-      snprintf_float(promote_float(value), specs.precision, fspecs, buffer);
-      write_padded(specs, str_writer<char>{buffer.data(), buffer.size()});
-      return;
-    }
-    int precision = specs.precision >= 0 || !specs.type ? specs.precision : 6;
-    if (fspecs.format == float_format::exp) ++precision;
-    if (const_check(std::is_same<T, float>())) fspecs.binary32 = true;
-    fspecs.use_grisu = use_grisu<T>();
-    if (const_check(FMT_DEPRECATED_PERCENT) && fspecs.percent) value *= 100;
-    int exp = format_float(promote_float(value), precision, fspecs, buffer);
-    if (const_check(FMT_DEPRECATED_PERCENT) && fspecs.percent) {
-      buffer.push_back('%');
-      --exp;  // Adjust decimal place position.
-    }
-    fspecs.precision = precision;
-    char_type point = fspecs.locale ? decimal_point<char_type>(locale_)
-                                    : static_cast<char_type>('.');
-    write_padded(specs, float_writer<char_type>(buffer.data(),
-                                                static_cast<int>(buffer.size()),
-                                                exp, fspecs, point));
+  // Attempts to reserve space for n extra characters in the output range.
+  // Returns a pointer to the reserved range or a reference to out_.
+  auto reserve(size_t n) -> decltype(detail::reserve(out_, n)) {
+    return detail::reserve(out_, n);
+  }
+
+  using reserve_iterator = remove_reference_t<decltype(
+      detail::reserve(std::declval<iterator&>(), 0))>;
+
+  template <typename T> void write_int(T value, const format_specs& spec) {
+    using uint_type = uint32_or_64_or_128_t<T>;
+    int_writer<iterator, Char, uint_type> w(out_, locale_, value, spec);
+    handle_int_type_spec(spec.type, w);
+    out_ = w.out;
   }
 
   void write(char value) {
@@ -1728,191 +2153,193 @@ template <typename Range> class basic_writer {
     *it++ = value;
   }
 
-  template <typename Char, FMT_ENABLE_IF(std::is_same<Char, char_type>::value)>
-  void write(Char value) {
-    auto&& it = reserve(1);
-    *it++ = value;
+  template <typename Ch, FMT_ENABLE_IF(std::is_same<Ch, Char>::value)>
+  void write(Ch value) {
+    out_ = detail::write<Char>(out_, value);
   }
 
   void write(string_view value) {
     auto&& it = reserve(value.size());
-    it = copy_str<char_type>(value.begin(), value.end(), it);
+    it = copy_str<Char>(value.begin(), value.end(), it);
   }
   void write(wstring_view value) {
-    static_assert(std::is_same<char_type, wchar_t>::value, "");
+    static_assert(std::is_same<Char, wchar_t>::value, "");
     auto&& it = reserve(value.size());
     it = std::copy(value.begin(), value.end(), it);
   }
 
-  template <typename Char>
-  void write(const Char* s, std::size_t size, const format_specs& specs) {
-    write_padded(specs, str_writer<Char>{s, size});
+  template <typename Ch>
+  void write(const Ch* s, size_t size, const format_specs& specs) {
+    auto width = specs.width != 0
+                     ? count_code_points(basic_string_view<Ch>(s, size))
+                     : 0;
+    out_ = write_padded(out_, specs, size, width, [=](reserve_iterator it) {
+      return copy_str<Char>(s, s + size, it);
+    });
   }
 
-  template <typename Char>
-  void write(basic_string_view<Char> s, const format_specs& specs = {}) {
-    const Char* data = s.data();
-    std::size_t size = s.size();
-    if (specs.precision >= 0 && to_unsigned(specs.precision) < size)
-      size = code_point_index(s, to_unsigned(specs.precision));
-    write(data, size, specs);
+  template <typename Ch>
+  void write(basic_string_view<Ch> s, const format_specs& specs = {}) {
+    out_ = detail::write(out_, s, specs);
   }
 
-  template <typename UIntPtr>
-  void write_pointer(UIntPtr value, const format_specs* specs) {
-    int num_digits = count_digits<4>(value);
-    auto pw = pointer_writer<UIntPtr>{value, num_digits};
-    if (!specs) return pw(reserve(to_unsigned(num_digits) + 2));
-    format_specs specs_copy = *specs;
-    if (specs_copy.align == align::none) specs_copy.align = align::right;
-    write_padded(specs_copy, pw);
+  void write_pointer(const void* p) {
+    out_ = write_ptr<char_type>(out_, to_uintptr(p), specs_);
   }
-};
-
-using writer = basic_writer<buffer_range<char>>;
 
-template <typename T> struct is_integral : std::is_integral<T> {};
-template <> struct is_integral<int128_t> : std::true_type {};
-template <> struct is_integral<uint128_t> : std::true_type {};
+  struct char_spec_handler : ErrorHandler {
+    arg_formatter_base& formatter;
+    Char value;
 
-template <typename Range, typename ErrorHandler = internal::error_handler>
-class arg_formatter_base {
- public:
-  using char_type = typename Range::value_type;
-  using iterator = typename Range::iterator;
-  using format_specs = basic_format_specs<char_type>;
+    char_spec_handler(arg_formatter_base& f, Char val)
+        : formatter(f), value(val) {}
 
- private:
-  using writer_type = basic_writer<Range>;
-  writer_type writer_;
-  format_specs* specs_;
+    void on_int() {
+      // char is only formatted as int if there are specs.
+      formatter.write_int(static_cast<int>(value), *formatter.specs_);
+    }
+    void on_char() {
+      if (formatter.specs_)
+        formatter.out_ = write_char(formatter.out_, value, *formatter.specs_);
+      else
+        formatter.write(value);
+    }
+  };
 
-  struct char_writer {
-    char_type value;
+  struct cstring_spec_handler : error_handler {
+    arg_formatter_base& formatter;
+    const Char* value;
 
-    size_t size() const { return 1; }
-    size_t width() const { return 1; }
+    cstring_spec_handler(arg_formatter_base& f, const Char* val)
+        : formatter(f), value(val) {}
 
-    template <typename It> void operator()(It&& it) const { *it++ = value; }
+    void on_string() { formatter.write(value); }
+    void on_pointer() { formatter.write_pointer(value); }
   };
 
-  void write_char(char_type value) {
-    if (specs_)
-      writer_.write_padded(*specs_, char_writer{value});
-    else
-      writer_.write(value);
-  }
-
-  void write_pointer(const void* p) {
-    writer_.write_pointer(internal::to_uintptr(p), specs_);
-  }
-
  protected:
-  writer_type& writer() { return writer_; }
-  FMT_DEPRECATED format_specs* spec() { return specs_; }
+  iterator out() { return out_; }
   format_specs* specs() { return specs_; }
-  iterator out() { return writer_.out(); }
 
   void write(bool value) {
-    string_view sv(value ? "true" : "false");
-    specs_ ? writer_.write(sv, *specs_) : writer_.write(sv);
+    if (specs_)
+      write(string_view(value ? "true" : "false"), *specs_);
+    else
+      out_ = detail::write<Char>(out_, value);
   }
 
-  void write(const char_type* value) {
+  void write(const Char* value) {
     if (!value) {
       FMT_THROW(format_error("string pointer is null"));
     } else {
       auto length = std::char_traits<char_type>::length(value);
       basic_string_view<char_type> sv(value, length);
-      specs_ ? writer_.write(sv, *specs_) : writer_.write(sv);
+      specs_ ? write(sv, *specs_) : write(sv);
     }
   }
 
  public:
-  arg_formatter_base(Range r, format_specs* s, locale_ref loc)
-      : writer_(r, loc), specs_(s) {}
+  arg_formatter_base(OutputIt out, format_specs* s, locale_ref loc)
+      : out_(out), locale_(loc), specs_(s) {}
 
   iterator operator()(monostate) {
     FMT_ASSERT(false, "invalid argument type");
-    return out();
+    return out_;
   }
 
   template <typename T, FMT_ENABLE_IF(is_integral<T>::value)>
-  iterator operator()(T value) {
+  FMT_INLINE iterator operator()(T value) {
     if (specs_)
-      writer_.write_int(value, *specs_);
+      write_int(value, *specs_);
     else
-      writer_.write(value);
-    return out();
+      out_ = detail::write<Char>(out_, value);
+    return out_;
   }
 
-  iterator operator()(char_type value) {
-    internal::handle_char_specs(
-        specs_, char_spec_handler(*this, static_cast<char_type>(value)));
-    return out();
+  iterator operator()(Char value) {
+    handle_char_specs(specs_,
+                      char_spec_handler(*this, static_cast<Char>(value)));
+    return out_;
   }
 
   iterator operator()(bool value) {
     if (specs_ && specs_->type) return (*this)(value ? 1 : 0);
     write(value != 0);
-    return out();
+    return out_;
   }
 
   template <typename T, FMT_ENABLE_IF(std::is_floating_point<T>::value)>
   iterator operator()(T value) {
-    writer_.write(value, specs_ ? *specs_ : format_specs());
-    return out();
+    auto specs = specs_ ? *specs_ : format_specs();
+    if (const_check(is_supported_floating_point(value)))
+      out_ = detail::write(out_, value, specs, locale_);
+    else
+      FMT_ASSERT(false, "unsupported float argument type");
+    return out_;
   }
 
-  struct char_spec_handler : ErrorHandler {
-    arg_formatter_base& formatter;
-    char_type value;
-
-    char_spec_handler(arg_formatter_base& f, char_type val)
-        : formatter(f), value(val) {}
-
-    void on_int() {
-      if (formatter.specs_)
-        formatter.writer_.write_int(value, *formatter.specs_);
-      else
-        formatter.writer_.write(value);
-    }
-    void on_char() { formatter.write_char(value); }
-  };
-
-  struct cstring_spec_handler : internal::error_handler {
-    arg_formatter_base& formatter;
-    const char_type* value;
-
-    cstring_spec_handler(arg_formatter_base& f, const char_type* val)
-        : formatter(f), value(val) {}
-
-    void on_string() { formatter.write(value); }
-    void on_pointer() { formatter.write_pointer(value); }
-  };
-
-  iterator operator()(const char_type* value) {
-    if (!specs_) return write(value), out();
-    internal::handle_cstring_type_spec(specs_->type,
-                                       cstring_spec_handler(*this, value));
-    return out();
+  iterator operator()(const Char* value) {
+    if (!specs_) return write(value), out_;
+    handle_cstring_type_spec(specs_->type, cstring_spec_handler(*this, value));
+    return out_;
   }
 
-  iterator operator()(basic_string_view<char_type> value) {
+  iterator operator()(basic_string_view<Char> value) {
     if (specs_) {
-      internal::check_string_type_spec(specs_->type, internal::error_handler());
-      writer_.write(value, *specs_);
+      check_string_type_spec(specs_->type, error_handler());
+      write(value, *specs_);
     } else {
-      writer_.write(value);
+      write(value);
     }
-    return out();
+    return out_;
   }
 
   iterator operator()(const void* value) {
-    if (specs_)
-      check_pointer_type_spec(specs_->type, internal::error_handler());
+    if (specs_) check_pointer_type_spec(specs_->type, error_handler());
     write_pointer(value);
-    return out();
+    return out_;
+  }
+};
+
+/** The default argument formatter. */
+template <typename OutputIt, typename Char>
+class arg_formatter : public arg_formatter_base<OutputIt, Char> {
+ private:
+  using char_type = Char;
+  using base = arg_formatter_base<OutputIt, Char>;
+  using context_type = basic_format_context<OutputIt, Char>;
+
+  context_type& ctx_;
+  basic_format_parse_context<char_type>* parse_ctx_;
+  const Char* ptr_;
+
+ public:
+  using iterator = typename base::iterator;
+  using format_specs = typename base::format_specs;
+
+  /**
+    \rst
+    Constructs an argument formatter object.
+    *ctx* is a reference to the formatting context,
+    *specs* contains format specifier information for standard argument types.
+    \endrst
+   */
+  explicit arg_formatter(
+      context_type& ctx,
+      basic_format_parse_context<char_type>* parse_ctx = nullptr,
+      format_specs* specs = nullptr, const Char* ptr = nullptr)
+      : base(ctx.out(), specs, ctx.locale()),
+        ctx_(ctx),
+        parse_ctx_(parse_ctx),
+        ptr_(ptr) {}
+
+  using base::operator();
+
+  /** Formats an argument of a user-defined type. */
+  iterator operator()(typename basic_format_arg<context_type>::handle handle) {
+    if (ptr_) advance_to(*parse_ctx_, ptr_);
+    handle.format(*parse_ctx_, ctx_);
+    return ctx_.out();
   }
 };
 
@@ -1926,10 +2353,6 @@ template <typename Char, typename ErrorHandler>
 FMT_CONSTEXPR int parse_nonnegative_int(const Char*& begin, const Char* end,
                                         ErrorHandler&& eh) {
   FMT_ASSERT(begin != end && '0' <= *begin && *begin <= '9', "");
-  if (*begin == '0') {
-    ++begin;
-    return 0;
-  }
   unsigned value = 0;
   // Convert to unsigned to prevent a warning.
   constexpr unsigned max_int = max_value<int>();
@@ -1959,12 +2382,11 @@ template <typename Context> class custom_formatter {
                             Context& ctx)
       : parse_ctx_(parse_ctx), ctx_(ctx) {}
 
-  bool operator()(typename basic_format_arg<Context>::handle h) const {
+  void operator()(typename basic_format_arg<Context>::handle h) const {
     h.format(parse_ctx_, ctx_);
-    return true;
   }
 
-  template <typename T> bool operator()(T) const { return false; }
+  template <typename T> void operator()(T) const {}
 };
 
 template <typename T>
@@ -2023,7 +2445,9 @@ template <typename Char> class specs_setter {
       : specs_(other.specs_) {}
 
   FMT_CONSTEXPR void on_align(align_t align) { specs_.align = align; }
-  FMT_CONSTEXPR void on_fill(Char fill) { specs_.fill[0] = fill; }
+  FMT_CONSTEXPR void on_fill(basic_string_view<Char> fill) {
+    specs_.fill = fill;
+  }
   FMT_CONSTEXPR void on_plus() { specs_.sign = sign::plus; }
   FMT_CONSTEXPR void on_minus() { specs_.sign = sign::minus; }
   FMT_CONSTEXPR void on_space() { specs_.sign = sign::space; }
@@ -2050,7 +2474,7 @@ template <typename Char> class specs_setter {
 
 template <typename ErrorHandler> class numeric_specs_checker {
  public:
-  FMT_CONSTEXPR numeric_specs_checker(ErrorHandler& eh, internal::type arg_type)
+  FMT_CONSTEXPR numeric_specs_checker(ErrorHandler& eh, detail::type arg_type)
       : error_handler_(eh), arg_type_(arg_type) {}
 
   FMT_CONSTEXPR void require_numeric_argument() {
@@ -2060,31 +2484,37 @@ template <typename ErrorHandler> class numeric_specs_checker {
 
   FMT_CONSTEXPR void check_sign() {
     require_numeric_argument();
-    if (is_integral_type(arg_type_) && arg_type_ != int_type &&
-        arg_type_ != long_long_type && arg_type_ != internal::char_type) {
+    if (is_integral_type(arg_type_) && arg_type_ != type::int_type &&
+        arg_type_ != type::long_long_type && arg_type_ != type::char_type) {
       error_handler_.on_error("format specifier requires signed argument");
     }
   }
 
   FMT_CONSTEXPR void check_precision() {
-    if (is_integral_type(arg_type_) || arg_type_ == internal::pointer_type)
+    if (is_integral_type(arg_type_) || arg_type_ == type::pointer_type)
       error_handler_.on_error("precision not allowed for this argument type");
   }
 
  private:
   ErrorHandler& error_handler_;
-  internal::type arg_type_;
+  detail::type arg_type_;
 };
 
 // A format specifier handler that checks if specifiers are consistent with the
 // argument type.
 template <typename Handler> class specs_checker : public Handler {
+ private:
+  numeric_specs_checker<Handler> checker_;
+
+  // Suppress an MSVC warning about using this in initializer list.
+  FMT_CONSTEXPR Handler& error_handler() { return *this; }
+
  public:
-  FMT_CONSTEXPR specs_checker(const Handler& handler, internal::type arg_type)
-      : Handler(handler), checker_(*this, arg_type) {}
+  FMT_CONSTEXPR specs_checker(const Handler& handler, detail::type arg_type)
+      : Handler(handler), checker_(error_handler(), arg_type) {}
 
   FMT_CONSTEXPR specs_checker(const specs_checker& other)
-      : Handler(other), checker_(*this, other.arg_type_) {}
+      : Handler(other), checker_(error_handler(), other.arg_type_) {}
 
   FMT_CONSTEXPR void on_align(align_t align) {
     if (align == align::numeric) checker_.require_numeric_argument();
@@ -2117,9 +2547,6 @@ template <typename Handler> class specs_checker : public Handler {
   }
 
   FMT_CONSTEXPR void end_precision() { checker_.check_precision(); }
-
- private:
-  numeric_specs_checker<Handler> checker_;
 };
 
 template <template <typename> class Handler, typename FormatArg,
@@ -2132,10 +2559,10 @@ FMT_CONSTEXPR int get_dynamic_spec(FormatArg arg, ErrorHandler eh) {
 
 struct auto_id {};
 
-template <typename Context>
-FMT_CONSTEXPR typename Context::format_arg get_arg(Context& ctx, int id) {
+template <typename Context, typename ID>
+FMT_CONSTEXPR typename Context::format_arg get_arg(Context& ctx, ID id) {
   auto arg = ctx.arg(id);
-  if (!arg) ctx.on_error("argument index out of range");
+  if (!arg) ctx.on_error("argument not found");
   return arg;
 }
 
@@ -2168,17 +2595,17 @@ class specs_handler : public specs_setter<typename Context::char_type> {
   using format_arg = typename Context::format_arg;
 
   FMT_CONSTEXPR format_arg get_arg(auto_id) {
-    return internal::get_arg(context_, parse_context_.next_arg_id());
+    return detail::get_arg(context_, parse_context_.next_arg_id());
   }
 
   FMT_CONSTEXPR format_arg get_arg(int arg_id) {
     parse_context_.check_arg_id(arg_id);
-    return internal::get_arg(context_, arg_id);
+    return detail::get_arg(context_, arg_id);
   }
 
   FMT_CONSTEXPR format_arg get_arg(basic_string_view<char_type> arg_id) {
     parse_context_.check_arg_id(arg_id);
-    return context_.arg(arg_id);
+    return detail::get_arg(context_, arg_id);
   }
 
   ParseContext& parse_context_;
@@ -2190,6 +2617,7 @@ enum class arg_id_kind { none, index, name };
 // An argument reference.
 template <typename Char> struct arg_ref {
   FMT_CONSTEXPR arg_ref() : kind(arg_id_kind::none), val() {}
+
   FMT_CONSTEXPR explicit arg_ref(int index)
       : kind(arg_id_kind::index), val(index) {}
   FMT_CONSTEXPR explicit arg_ref(basic_string_view<Char> name)
@@ -2282,7 +2710,11 @@ FMT_CONSTEXPR const Char* parse_arg_id(const Char* begin, const Char* end,
     return begin;
   }
   if (c >= '0' && c <= '9') {
-    int index = parse_nonnegative_int(begin, end, handler);
+    int index = 0;
+    if (c != '0')
+      index = parse_nonnegative_int(begin, end, handler);
+    else
+      ++begin;
     if (begin == end || (*begin != '}' && *begin != ':'))
       handler.on_error("invalid format string");
     else
@@ -2335,23 +2767,50 @@ template <typename SpecHandler, typename Char> struct precision_adapter {
   SpecHandler& handler;
 };
 
+template <typename Char>
+FMT_CONSTEXPR int code_point_length(const Char* begin) {
+  if (const_check(sizeof(Char) != 1)) return 1;
+  constexpr char lengths[] = {1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+                              0, 0, 0, 0, 0, 0, 0, 0, 2, 2, 2, 2, 3, 3, 4, 0};
+  int len = lengths[static_cast<unsigned char>(*begin) >> 3];
+
+  // Compute the pointer to the next character early so that the next
+  // iteration can start working on the next character. Neither Clang
+  // nor GCC figure out this reordering on their own.
+  return len + !len;
+}
+
+template <typename Char> constexpr bool is_ascii_letter(Char c) {
+  return (c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z');
+}
+
+// Converts a character to ASCII. Returns a number > 127 on conversion failure.
+template <typename Char, FMT_ENABLE_IF(std::is_integral<Char>::value)>
+constexpr Char to_ascii(Char value) {
+  return value;
+}
+template <typename Char, FMT_ENABLE_IF(std::is_enum<Char>::value)>
+constexpr typename std::underlying_type<Char>::type to_ascii(Char value) {
+  return value;
+}
+
 // Parses fill and alignment.
 template <typename Char, typename Handler>
 FMT_CONSTEXPR const Char* parse_align(const Char* begin, const Char* end,
                                       Handler&& handler) {
   FMT_ASSERT(begin != end, "");
   auto align = align::none;
-  int i = 0;
-  if (begin + 1 != end) ++i;
-  do {
-    switch (static_cast<char>(begin[i])) {
+  auto p = begin + code_point_length(begin);
+  if (p >= end) p = begin;
+  for (;;) {
+    switch (to_ascii(*p)) {
     case '<':
       align = align::left;
       break;
     case '>':
       align = align::right;
       break;
-#if FMT_NUMERIC_ALIGN
+#if FMT_DEPRECATED_NUMERIC_ALIGN
     case '=':
       align = align::numeric;
       break;
@@ -2361,18 +2820,21 @@ FMT_CONSTEXPR const Char* parse_align(const Char* begin, const Char* end,
       break;
     }
     if (align != align::none) {
-      if (i > 0) {
+      if (p != begin) {
         auto c = *begin;
         if (c == '{')
           return handler.on_error("invalid fill character '{'"), begin;
-        begin += 2;
-        handler.on_fill(c);
+        handler.on_fill(basic_string_view<Char>(begin, to_unsigned(p - begin)));
+        begin = p + 1;
       } else
         ++begin;
       handler.on_align(align);
       break;
+    } else if (p == begin) {
+      break;
     }
-  } while (i-- > 0);
+    p = begin;
+  }
   return begin;
 }
 
@@ -2420,13 +2882,13 @@ FMT_CONSTEXPR const Char* parse_precision(const Char* begin, const Char* end,
 template <typename Char, typename SpecHandler>
 FMT_CONSTEXPR const Char* parse_format_specs(const Char* begin, const Char* end,
                                              SpecHandler&& handler) {
-  if (begin == end || *begin == '}') return begin;
+  if (begin == end) return begin;
 
   begin = parse_align(begin, end, handler);
   if (begin == end) return begin;
 
   // Parse sign.
-  switch (static_cast<char>(*begin)) {
+  switch (to_ascii(*begin)) {
   case '+':
     handler.on_plus();
     ++begin;
@@ -2479,71 +2941,98 @@ template <>
 inline bool find<false, char>(const char* first, const char* last, char value,
                               const char*& out) {
   out = static_cast<const char*>(
-      std::memchr(first, value, internal::to_unsigned(last - first)));
+      std::memchr(first, value, detail::to_unsigned(last - first)));
   return out != nullptr;
 }
 
 template <typename Handler, typename Char> struct id_adapter {
-  FMT_CONSTEXPR void operator()() { handler.on_arg_id(); }
-  FMT_CONSTEXPR void operator()(int id) { handler.on_arg_id(id); }
+  Handler& handler;
+  int arg_id;
+
+  FMT_CONSTEXPR void operator()() { arg_id = handler.on_arg_id(); }
+  FMT_CONSTEXPR void operator()(int id) { arg_id = handler.on_arg_id(id); }
   FMT_CONSTEXPR void operator()(basic_string_view<Char> id) {
-    handler.on_arg_id(id);
+    arg_id = handler.on_arg_id(id);
   }
   FMT_CONSTEXPR void on_error(const char* message) {
     handler.on_error(message);
   }
-  Handler& handler;
 };
 
+template <typename Char, typename Handler>
+FMT_CONSTEXPR const Char* parse_replacement_field(const Char* begin,
+                                                  const Char* end,
+                                                  Handler&& handler) {
+  ++begin;
+  if (begin == end) return handler.on_error("invalid format string"), end;
+  if (*begin == '}') {
+    handler.on_replacement_field(handler.on_arg_id(), begin);
+  } else if (*begin == '{') {
+    handler.on_text(begin, begin + 1);
+  } else {
+    auto adapter = id_adapter<Handler, Char>{handler, 0};
+    begin = parse_arg_id(begin, end, adapter);
+    Char c = begin != end ? *begin : Char();
+    if (c == '}') {
+      handler.on_replacement_field(adapter.arg_id, begin);
+    } else if (c == ':') {
+      begin = handler.on_format_specs(adapter.arg_id, begin + 1, end);
+      if (begin == end || *begin != '}')
+        return handler.on_error("unknown format specifier"), end;
+    } else {
+      return handler.on_error("missing '}' in format string"), end;
+    }
+  }
+  return begin + 1;
+}
+
 template <bool IS_CONSTEXPR, typename Char, typename Handler>
-FMT_CONSTEXPR void parse_format_string(basic_string_view<Char> format_str,
-                                       Handler&& handler) {
-  struct pfs_writer {
-    FMT_CONSTEXPR void operator()(const Char* begin, const Char* end) {
-      if (begin == end) return;
+FMT_CONSTEXPR_DECL FMT_INLINE void parse_format_string(
+    basic_string_view<Char> format_str, Handler&& handler) {
+  auto begin = format_str.data();
+  auto end = begin + format_str.size();
+  if (end - begin < 32) {
+    // Use a simple loop instead of memchr for small strings.
+    const Char* p = begin;
+    while (p != end) {
+      auto c = *p++;
+      if (c == '{') {
+        handler.on_text(begin, p - 1);
+        begin = p = parse_replacement_field(p - 1, end, handler);
+      } else if (c == '}') {
+        if (p == end || *p != '}')
+          return handler.on_error("unmatched '}' in format string");
+        handler.on_text(begin, p);
+        begin = ++p;
+      }
+    }
+    handler.on_text(begin, end);
+    return;
+  }
+  struct writer {
+    FMT_CONSTEXPR void operator()(const Char* pbegin, const Char* pend) {
+      if (pbegin == pend) return;
       for (;;) {
         const Char* p = nullptr;
-        if (!find<IS_CONSTEXPR>(begin, end, '}', p))
-          return handler_.on_text(begin, end);
+        if (!find<IS_CONSTEXPR>(pbegin, pend, '}', p))
+          return handler_.on_text(pbegin, pend);
         ++p;
-        if (p == end || *p != '}')
+        if (p == pend || *p != '}')
           return handler_.on_error("unmatched '}' in format string");
-        handler_.on_text(begin, p);
-        begin = p + 1;
+        handler_.on_text(pbegin, p);
+        pbegin = p + 1;
       }
     }
     Handler& handler_;
   } write{handler};
-  auto begin = format_str.data();
-  auto end = begin + format_str.size();
   while (begin != end) {
     // Doing two passes with memchr (one for '{' and another for '}') is up to
     // 2.5x faster than the naive one-pass implementation on big format strings.
     const Char* p = begin;
-    if (*begin != '{' && !find<IS_CONSTEXPR>(begin, end, '{', p))
+    if (*begin != '{' && !find<IS_CONSTEXPR>(begin + 1, end, '{', p))
       return write(begin, end);
     write(begin, p);
-    ++p;
-    if (p == end) return handler.on_error("invalid format string");
-    if (static_cast<char>(*p) == '}') {
-      handler.on_arg_id();
-      handler.on_replacement_field(p);
-    } else if (*p == '{') {
-      handler.on_text(p, p + 1);
-    } else {
-      p = parse_arg_id(p, end, id_adapter<Handler, Char>{handler});
-      Char c = p != end ? *p : Char();
-      if (c == '}') {
-        handler.on_replacement_field(p);
-      } else if (c == ':') {
-        p = handler.on_format_specs(p + 1, end);
-        if (p == end || *p != '}')
-          return handler.on_error("unknown format specifier");
-      } else {
-        return handler.on_error("missing '}' in format string");
-      }
-    }
-    begin = p + 1;
+    begin = parse_replacement_field(p, end, handler);
   }
 }
 
@@ -2553,44 +3042,128 @@ FMT_CONSTEXPR const typename ParseContext::char_type* parse_format_specs(
   using char_type = typename ParseContext::char_type;
   using context = buffer_context<char_type>;
   using mapped_type =
-      conditional_t<internal::mapped_type_constant<T, context>::value !=
-                        internal::custom_type,
+      conditional_t<detail::mapped_type_constant<T, context>::value !=
+                        type::custom_type,
                     decltype(arg_mapper<context>().map(std::declval<T>())), T>;
   auto f = conditional_t<has_formatter<mapped_type, context>::value,
                          formatter<mapped_type, char_type>,
-                         internal::fallback_formatter<T, char_type>>();
+                         detail::fallback_formatter<T, char_type>>();
   return f.parse(ctx);
 }
 
+template <typename OutputIt, typename Char, typename Context>
+struct format_handler : detail::error_handler {
+  basic_format_parse_context<Char> parse_context;
+  Context context;
+
+  format_handler(OutputIt out,
+                 basic_string_view<Char> str,
+                 basic_format_args<Context> format_args, detail::locale_ref loc)
+      : parse_context(str), context(out, format_args, loc) {}
+
+  void on_text(const Char* begin, const Char* end) {
+    auto size = to_unsigned(end - begin);
+    auto out = context.out();
+    auto&& it = reserve(out, size);
+    it = std::copy_n(begin, size, it);
+    context.advance_to(out);
+  }
+
+  int on_arg_id() { return parse_context.next_arg_id(); }
+  int on_arg_id(int id) { return parse_context.check_arg_id(id), id; }
+  int on_arg_id(basic_string_view<Char> id) {
+    int arg_id = context.arg_id(id);
+    if (arg_id < 0) on_error("argument not found");
+    return arg_id;
+  }
+
+  FMT_INLINE void on_replacement_field(int id, const Char*) {
+    auto arg = get_arg(context, id);
+    context.advance_to(visit_format_arg(
+        default_arg_formatter<OutputIt, Char>{
+            context.out(), context.args(), context.locale()},
+        arg));
+  }
+
+  const Char* on_format_specs(int id, const Char* begin, const Char* end) {
+    auto arg = get_arg(context, id);
+    if (arg.type() == type::custom_type) {
+      advance_to(parse_context, begin);
+      visit_format_arg(custom_formatter<Context>(parse_context, context), arg);
+      return parse_context.begin();
+    }
+    auto specs = basic_format_specs<Char>();
+    if (begin + 1 < end && begin[1] == '}' && is_ascii_letter(*begin)) {
+      specs.type = static_cast<char>(*begin++);
+    } else {
+      using parse_context_t = basic_format_parse_context<Char>;
+      specs_checker<specs_handler<parse_context_t, Context>> handler(
+          specs_handler<parse_context_t, Context>(specs, parse_context,
+                                                  context),
+          arg.type());
+      begin = parse_format_specs(begin, end, handler);
+      if (begin == end || *begin != '}')
+        on_error("missing '}' in format string");
+    }
+    context.advance_to(
+        visit_format_arg(arg_formatter<OutputIt, Char>(context, &parse_context, &specs), arg));
+    return begin;
+  }
+};
+
+// A parse context with extra argument id checks. It is only used at compile
+// time because adding checks at runtime would introduce substantial overhead
+// and would be redundant since argument ids are checked when arguments are
+// retrieved anyway.
+template <typename Char, typename ErrorHandler = error_handler>
+class compile_parse_context
+    : public basic_format_parse_context<Char, ErrorHandler> {
+ private:
+  int num_args_;
+  using base = basic_format_parse_context<Char, ErrorHandler>;
+
+ public:
+  explicit FMT_CONSTEXPR compile_parse_context(
+      basic_string_view<Char> format_str, int num_args = max_value<int>(),
+      ErrorHandler eh = {})
+      : base(format_str, eh), num_args_(num_args) {}
+
+  FMT_CONSTEXPR int next_arg_id() {
+    int id = base::next_arg_id();
+    if (id >= num_args_) this->on_error("argument not found");
+    return id;
+  }
+
+  FMT_CONSTEXPR void check_arg_id(int id) {
+    base::check_arg_id(id);
+    if (id >= num_args_) this->on_error("argument not found");
+  }
+  using base::check_arg_id;
+};
+
 template <typename Char, typename ErrorHandler, typename... Args>
 class format_string_checker {
  public:
   explicit FMT_CONSTEXPR format_string_checker(
       basic_string_view<Char> format_str, ErrorHandler eh)
-      : arg_id_(-1),
-        context_(format_str, eh),
+      : context_(format_str, num_args, eh),
         parse_funcs_{&parse_format_specs<Args, parse_context_type>...} {}
 
   FMT_CONSTEXPR void on_text(const Char*, const Char*) {}
 
-  FMT_CONSTEXPR void on_arg_id() {
-    arg_id_ = context_.next_arg_id();
-    check_arg_id();
-  }
-  FMT_CONSTEXPR void on_arg_id(int id) {
-    arg_id_ = id;
-    context_.check_arg_id(id);
-    check_arg_id();
-  }
-  FMT_CONSTEXPR void on_arg_id(basic_string_view<Char>) {
+  FMT_CONSTEXPR int on_arg_id() { return context_.next_arg_id(); }
+  FMT_CONSTEXPR int on_arg_id(int id) { return context_.check_arg_id(id), id; }
+  FMT_CONSTEXPR int on_arg_id(basic_string_view<Char>) {
     on_error("compile-time checks don't support named arguments");
+    return 0;
   }
 
-  FMT_CONSTEXPR void on_replacement_field(const Char*) {}
+  FMT_CONSTEXPR void on_replacement_field(int, const Char*) {}
 
-  FMT_CONSTEXPR const Char* on_format_specs(const Char* begin, const Char*) {
+  FMT_CONSTEXPR const Char* on_format_specs(int id, const Char* begin,
+                                            const Char*) {
     advance_to(context_, begin);
-    return arg_id_ < num_args ? parse_funcs_[arg_id_](context_) : begin;
+    return id < num_args ? parse_funcs_[id](context_) : begin;
   }
 
   FMT_CONSTEXPR void on_error(const char* message) {
@@ -2598,36 +3171,66 @@ class format_string_checker {
   }
 
  private:
-  using parse_context_type = basic_format_parse_context<Char, ErrorHandler>;
+  using parse_context_type = compile_parse_context<Char, ErrorHandler>;
   enum { num_args = sizeof...(Args) };
 
-  FMT_CONSTEXPR void check_arg_id() {
-    if (arg_id_ >= num_args) context_.on_error("argument index out of range");
-  }
-
   // Format specifier parsing function.
   using parse_func = const Char* (*)(parse_context_type&);
 
-  int arg_id_;
   parse_context_type context_;
   parse_func parse_funcs_[num_args > 0 ? num_args : 1];
 };
 
-template <typename Char, typename ErrorHandler, typename... Args>
-FMT_CONSTEXPR bool do_check_format_string(basic_string_view<Char> s,
-                                          ErrorHandler eh = ErrorHandler()) {
-  format_string_checker<Char, ErrorHandler, Args...> checker(s, eh);
-  parse_format_string<true>(s, checker);
-  return true;
+// Converts string literals to basic_string_view.
+template <typename Char, size_t N>
+FMT_CONSTEXPR basic_string_view<Char> compile_string_to_view(
+    const Char (&s)[N]) {
+  // Remove trailing null character if needed. Won't be present if this is used
+  // with raw character array (i.e. not defined as a string).
+  return {s,
+          N - ((std::char_traits<Char>::to_int_type(s[N - 1]) == 0) ? 1 : 0)};
 }
 
+// Converts string_view to basic_string_view.
+template <typename Char>
+FMT_CONSTEXPR basic_string_view<Char> compile_string_to_view(
+    const std_string_view<Char>& s) {
+  return {s.data(), s.size()};
+}
+
+#define FMT_STRING_IMPL(s, base)                                  \
+  [] {                                                            \
+    /* Use a macro-like name to avoid shadowing warnings. */      \
+    struct FMT_COMPILE_STRING : base {                            \
+      using char_type = fmt::remove_cvref_t<decltype(s[0])>;      \
+      FMT_MAYBE_UNUSED FMT_CONSTEXPR                              \
+      operator fmt::basic_string_view<char_type>() const {        \
+        return fmt::detail::compile_string_to_view<char_type>(s); \
+      }                                                           \
+    };                                                            \
+    return FMT_COMPILE_STRING();                                  \
+  }()
+
+/**
+  \rst
+  Constructs a compile-time format string from a string literal *s*.
+
+  **Example**::
+
+    // A compile-time error because 'd' is an invalid specifier for strings.
+    std::string s = fmt::format(FMT_STRING("{:d}"), "foo");
+  \endrst
+ */
+#define FMT_STRING(s) FMT_STRING_IMPL(s, fmt::compile_string)
+
 template <typename... Args, typename S,
           enable_if_t<(is_compile_string<S>::value), int>>
 void check_format_string(S format_str) {
+  FMT_CONSTEXPR_DECL auto s = to_string_view(format_str);
+  using checker = format_string_checker<typename S::char_type, error_handler,
+                                        remove_cvref_t<Args>...>;
   FMT_CONSTEXPR_DECL bool invalid_format =
-      internal::do_check_format_string<typename S::char_type,
-                                       internal::error_handler, Args...>(
-          to_string_view(format_str));
+      (parse_format_string<true>(s, checker(s, {})), true);
   (void)invalid_format;
 }
 
@@ -2638,67 +3241,34 @@ void handle_dynamic_spec(int& value, arg_ref<typename Context::char_type> ref,
   case arg_id_kind::none:
     break;
   case arg_id_kind::index:
-    value = internal::get_dynamic_spec<Handler>(ctx.arg(ref.val.index),
-                                                ctx.error_handler());
+    value = detail::get_dynamic_spec<Handler>(ctx.arg(ref.val.index),
+                                              ctx.error_handler());
     break;
   case arg_id_kind::name:
-    value = internal::get_dynamic_spec<Handler>(ctx.arg(ref.val.name),
-                                                ctx.error_handler());
+    value = detail::get_dynamic_spec<Handler>(ctx.arg(ref.val.name),
+                                              ctx.error_handler());
     break;
   }
 }
-}  // namespace internal
-
-template <typename Range>
-using basic_writer FMT_DEPRECATED_ALIAS = internal::basic_writer<Range>;
-using writer FMT_DEPRECATED_ALIAS = internal::writer;
-using wwriter FMT_DEPRECATED_ALIAS =
-    internal::basic_writer<buffer_range<wchar_t>>;
 
-/** The default argument formatter. */
-template <typename Range>
-class arg_formatter : public internal::arg_formatter_base<Range> {
- private:
-  using char_type = typename Range::value_type;
-  using base = internal::arg_formatter_base<Range>;
-  using context_type = basic_format_context<typename base::iterator, char_type>;
-
-  context_type& ctx_;
-  basic_format_parse_context<char_type>* parse_ctx_;
-
- public:
-  using range = Range;
-  using iterator = typename base::iterator;
-  using format_specs = typename base::format_specs;
+using format_func = void (*)(detail::buffer<char>&, int, string_view);
 
-  /**
-    \rst
-    Constructs an argument formatter object.
-    *ctx* is a reference to the formatting context,
-    *specs* contains format specifier information for standard argument types.
-    \endrst
-   */
-  explicit arg_formatter(
-      context_type& ctx,
-      basic_format_parse_context<char_type>* parse_ctx = nullptr,
-      format_specs* specs = nullptr)
-      : base(Range(ctx.out()), specs, ctx.locale()),
-        ctx_(ctx),
-        parse_ctx_(parse_ctx) {}
+FMT_API void format_error_code(buffer<char>& out, int error_code,
+                               string_view message) FMT_NOEXCEPT;
 
-  using base::operator();
+FMT_API void report_error(format_func func, int error_code,
+                          string_view message) FMT_NOEXCEPT;
+}  // namespace detail
 
-  /** Formats an argument of a user-defined type. */
-  iterator operator()(typename basic_format_arg<context_type>::handle handle) {
-    handle.format(*parse_ctx_, ctx_);
-    return ctx_.out();
-  }
-};
+template <typename OutputIt, typename Char>
+using arg_formatter FMT_DEPRECATED_ALIAS =
+    detail::arg_formatter<OutputIt, Char>;
 
 /**
  An error returned by an operating system or a language runtime,
  for example a file opening error.
 */
+FMT_CLASS_API
 class FMT_API system_error : public std::runtime_error {
  private:
   void init(int err_code, string_view format_str, format_args args);
@@ -2757,7 +3327,7 @@ class FMT_API system_error : public std::runtime_error {
   may look like "Unknown error -1" and is platform-dependent.
   \endrst
  */
-FMT_API void format_system_error(internal::buffer<char>& out, int error_code,
+FMT_API void format_system_error(detail::buffer<char>& out, int error_code,
                                  string_view message) FMT_NOEXCEPT;
 
 // Reports a system error without throwing an exception.
@@ -2765,55 +3335,6 @@ FMT_API void format_system_error(internal::buffer<char>& out, int error_code,
 FMT_API void report_system_error(int error_code,
                                  string_view message) FMT_NOEXCEPT;
 
-#if FMT_USE_WINDOWS_H
-
-/** A Windows error. */
-class windows_error : public system_error {
- private:
-  FMT_API void init(int error_code, string_view format_str, format_args args);
-
- public:
-  /**
-   \rst
-   Constructs a :class:`fmt::windows_error` object with the description
-   of the form
-
-   .. parsed-literal::
-     *<message>*: *<system-message>*
-
-   where *<message>* is the formatted message and *<system-message>* is the
-   system message corresponding to the error code.
-   *error_code* is a Windows error code as given by ``GetLastError``.
-   If *error_code* is not a valid error code such as -1, the system message
-   will look like "error -1".
-
-   **Example**::
-
-     // This throws a windows_error with the description
-     //   cannot open file 'madeup': The system cannot find the file specified.
-     // or similar (system message may vary).
-     const char *filename = "madeup";
-     LPOFSTRUCT of = LPOFSTRUCT();
-     HFILE file = OpenFile(filename, &of, OF_READ);
-     if (file == HFILE_ERROR) {
-       throw fmt::windows_error(GetLastError(),
-                                "cannot open file '{}'", filename);
-     }
-   \endrst
-  */
-  template <typename... Args>
-  windows_error(int error_code, string_view message, const Args&... args) {
-    init(error_code, message, make_format_args(args...));
-  }
-};
-
-// Reports a Windows error without throwing an exception.
-// Can be used to report errors from destructors.
-FMT_API void report_windows_error(int error_code,
-                                  string_view message) FMT_NOEXCEPT;
-
-#endif
-
 /** Fast integer formatter. */
 class format_int {
  private:
@@ -2823,47 +3344,32 @@ class format_int {
   mutable char buffer_[buffer_size];
   char* str_;
 
-  // Formats value in reverse and returns a pointer to the beginning.
-  char* format_decimal(unsigned long long value) {
-    char* ptr = buffer_ + (buffer_size - 1);  // Parens to workaround MSVC bug.
-    while (value >= 100) {
-      // Integer division is slow so do it for a group of two digits instead
-      // of for every digit. The idea comes from the talk by Alexandrescu
-      // "Three Optimization Tips for C++". See speed-test for a comparison.
-      auto index = static_cast<unsigned>((value % 100) * 2);
-      value /= 100;
-      *--ptr = internal::data::digits[index + 1];
-      *--ptr = internal::data::digits[index];
-    }
-    if (value < 10) {
-      *--ptr = static_cast<char>('0' + value);
-      return ptr;
-    }
-    auto index = static_cast<unsigned>(value * 2);
-    *--ptr = internal::data::digits[index + 1];
-    *--ptr = internal::data::digits[index];
-    return ptr;
+  template <typename UInt> char* format_unsigned(UInt value) {
+    auto n = static_cast<detail::uint32_or_64_or_128_t<UInt>>(value);
+    return detail::format_decimal(buffer_, n, buffer_size - 1).begin;
   }
 
-  void format_signed(long long value) {
-    auto abs_value = static_cast<unsigned long long>(value);
+  template <typename Int> char* format_signed(Int value) {
+    auto abs_value = static_cast<detail::uint32_or_64_or_128_t<Int>>(value);
     bool negative = value < 0;
     if (negative) abs_value = 0 - abs_value;
-    str_ = format_decimal(abs_value);
-    if (negative) *--str_ = '-';
+    auto begin = format_unsigned(abs_value);
+    if (negative) *--begin = '-';
+    return begin;
   }
 
  public:
-  explicit format_int(int value) { format_signed(value); }
-  explicit format_int(long value) { format_signed(value); }
-  explicit format_int(long long value) { format_signed(value); }
-  explicit format_int(unsigned value) : str_(format_decimal(value)) {}
-  explicit format_int(unsigned long value) : str_(format_decimal(value)) {}
-  explicit format_int(unsigned long long value) : str_(format_decimal(value)) {}
+  explicit format_int(int value) : str_(format_signed(value)) {}
+  explicit format_int(long value) : str_(format_signed(value)) {}
+  explicit format_int(long long value) : str_(format_signed(value)) {}
+  explicit format_int(unsigned value) : str_(format_unsigned(value)) {}
+  explicit format_int(unsigned long value) : str_(format_unsigned(value)) {}
+  explicit format_int(unsigned long long value)
+      : str_(format_unsigned(value)) {}
 
   /** Returns the number of characters written to the output buffer. */
-  std::size_t size() const {
-    return internal::to_unsigned(buffer_ - str_ + buffer_size - 1);
+  size_t size() const {
+    return detail::to_unsigned(buffer_ - str_ + buffer_size - 1);
   }
 
   /**
@@ -2889,59 +3395,71 @@ class format_int {
   std::string str() const { return std::string(str_, size()); }
 };
 
-// A formatter specialization for the core types corresponding to internal::type
+// A formatter specialization for the core types corresponding to detail::type
 // constants.
 template <typename T, typename Char>
 struct formatter<T, Char,
-                 enable_if_t<internal::type_constant<T, Char>::value !=
-                             internal::custom_type>> {
+                 enable_if_t<detail::type_constant<T, Char>::value !=
+                             detail::type::custom_type>> {
   FMT_CONSTEXPR formatter() = default;
 
   // Parses format specifiers stopping either at the end of the range or at the
   // terminating '}'.
   template <typename ParseContext>
   FMT_CONSTEXPR auto parse(ParseContext& ctx) -> decltype(ctx.begin()) {
-    using handler_type = internal::dynamic_specs_handler<ParseContext>;
-    auto type = internal::type_constant<T, Char>::value;
-    internal::specs_checker<handler_type> handler(handler_type(specs_, ctx),
-                                                  type);
+    using handler_type = detail::dynamic_specs_handler<ParseContext>;
+    auto type = detail::type_constant<T, Char>::value;
+    detail::specs_checker<handler_type> handler(handler_type(specs_, ctx),
+                                                type);
     auto it = parse_format_specs(ctx.begin(), ctx.end(), handler);
     auto eh = ctx.error_handler();
     switch (type) {
-    case internal::none_type:
-    case internal::named_arg_type:
+    case detail::type::none_type:
       FMT_ASSERT(false, "invalid argument type");
       break;
-    case internal::int_type:
-    case internal::uint_type:
-    case internal::long_long_type:
-    case internal::ulong_long_type:
-    case internal::int128_type:
-    case internal::uint128_type:
-    case internal::bool_type:
+    case detail::type::int_type:
+    case detail::type::uint_type:
+    case detail::type::long_long_type:
+    case detail::type::ulong_long_type:
+    case detail::type::int128_type:
+    case detail::type::uint128_type:
+    case detail::type::bool_type:
       handle_int_type_spec(specs_.type,
-                           internal::int_type_checker<decltype(eh)>(eh));
+                           detail::int_type_checker<decltype(eh)>(eh));
       break;
-    case internal::char_type:
+    case detail::type::char_type:
       handle_char_specs(
-          &specs_, internal::char_specs_checker<decltype(eh)>(specs_.type, eh));
+          &specs_, detail::char_specs_checker<decltype(eh)>(specs_.type, eh));
       break;
-    case internal::float_type:
-    case internal::double_type:
-    case internal::long_double_type:
-      internal::parse_float_type_spec(specs_, eh);
+    case detail::type::float_type:
+      if (detail::const_check(FMT_USE_FLOAT))
+        detail::parse_float_type_spec(specs_, eh);
+      else
+        FMT_ASSERT(false, "float support disabled");
+      break;
+    case detail::type::double_type:
+      if (detail::const_check(FMT_USE_DOUBLE))
+        detail::parse_float_type_spec(specs_, eh);
+      else
+        FMT_ASSERT(false, "double support disabled");
+      break;
+    case detail::type::long_double_type:
+      if (detail::const_check(FMT_USE_LONG_DOUBLE))
+        detail::parse_float_type_spec(specs_, eh);
+      else
+        FMT_ASSERT(false, "long double support disabled");
       break;
-    case internal::cstring_type:
-      internal::handle_cstring_type_spec(
-          specs_.type, internal::cstring_type_checker<decltype(eh)>(eh));
+    case detail::type::cstring_type:
+      detail::handle_cstring_type_spec(
+          specs_.type, detail::cstring_type_checker<decltype(eh)>(eh));
       break;
-    case internal::string_type:
-      internal::check_string_type_spec(specs_.type, eh);
+    case detail::type::string_type:
+      detail::check_string_type_spec(specs_.type, eh);
       break;
-    case internal::pointer_type:
-      internal::check_pointer_type_spec(specs_.type, eh);
+    case detail::type::pointer_type:
+      detail::check_pointer_type_spec(specs_.type, eh);
       break;
-    case internal::custom_type:
+    case detail::type::custom_type:
       // Custom format specifiers should be checked in parse functions of
       // formatter specializations.
       break;
@@ -2951,26 +3469,25 @@ struct formatter<T, Char,
 
   template <typename FormatContext>
   auto format(const T& val, FormatContext& ctx) -> decltype(ctx.out()) {
-    internal::handle_dynamic_spec<internal::width_checker>(
-        specs_.width, specs_.width_ref, ctx);
-    internal::handle_dynamic_spec<internal::precision_checker>(
+    detail::handle_dynamic_spec<detail::width_checker>(specs_.width,
+                                                       specs_.width_ref, ctx);
+    detail::handle_dynamic_spec<detail::precision_checker>(
         specs_.precision, specs_.precision_ref, ctx);
-    using range_type =
-        internal::output_range<typename FormatContext::iterator,
-                               typename FormatContext::char_type>;
-    return visit_format_arg(arg_formatter<range_type>(ctx, nullptr, &specs_),
-                            internal::make_arg<FormatContext>(val));
+    using af = detail::arg_formatter<typename FormatContext::iterator,
+                                     typename FormatContext::char_type>;
+    return visit_format_arg(af(ctx, nullptr, &specs_),
+                            detail::make_arg<FormatContext>(val));
   }
 
  private:
-  internal::dynamic_format_specs<Char> specs_;
+  detail::dynamic_format_specs<Char> specs_;
 };
 
 #define FMT_FORMAT_AS(Type, Base)                                             \
   template <typename Char>                                                    \
   struct formatter<Type, Char> : formatter<Base, Char> {                      \
     template <typename FormatContext>                                         \
-    auto format(const Type& val, FormatContext& ctx) -> decltype(ctx.out()) { \
+    auto format(Type const& val, FormatContext& ctx) -> decltype(ctx.out()) { \
       return formatter<Base, Char>::format(val, ctx);                         \
     }                                                                         \
   }
@@ -2984,7 +3501,7 @@ FMT_FORMAT_AS(unsigned long, unsigned long long);
 FMT_FORMAT_AS(Char*, const Char*);
 FMT_FORMAT_AS(std::basic_string<Char>, basic_string_view<Char>);
 FMT_FORMAT_AS(std::nullptr_t, const void*);
-FMT_FORMAT_AS(internal::std_string_view<Char>, basic_string_view<Char>);
+FMT_FORMAT_AS(detail::std_string_view<Char>, basic_string_view<Char>);
 
 template <typename Char>
 struct formatter<void*, Char> : formatter<const void*, Char> {
@@ -3008,13 +3525,15 @@ struct formatter<Char[N], Char> : formatter<basic_string_view<Char>, Char> {
 //   using variant = std::variant<int, std::string>;
 //   template <>
 //   struct formatter<variant>: dynamic_formatter<> {
-//     void format(buffer &buf, const variant &v, context &ctx) {
-//       visit([&](const auto &val) { format(buf, val, ctx); }, v);
+//     auto format(const variant& v, format_context& ctx) {
+//       return visit([&](const auto& val) {
+//           return dynamic_formatter<>::format(val, ctx);
+//       }, v);
 //     }
 //   };
 template <typename Char = char> class dynamic_formatter {
  private:
-  struct null_handler : internal::error_handler {
+  struct null_handler : detail::error_handler {
     void on_align(align_t) {}
     void on_plus() {}
     void on_minus() {}
@@ -3027,16 +3546,15 @@ template <typename Char = char> class dynamic_formatter {
   auto parse(ParseContext& ctx) -> decltype(ctx.begin()) {
     format_str_ = ctx.begin();
     // Checks are deferred to formatting time when the argument type is known.
-    internal::dynamic_specs_handler<ParseContext> handler(specs_, ctx);
+    detail::dynamic_specs_handler<ParseContext> handler(specs_, ctx);
     return parse_format_specs(ctx.begin(), ctx.end(), handler);
   }
 
   template <typename T, typename FormatContext>
   auto format(const T& val, FormatContext& ctx) -> decltype(ctx.out()) {
     handle_specs(ctx);
-    internal::specs_checker<null_handler> checker(
-        null_handler(),
-        internal::mapped_type_constant<T, FormatContext>::value);
+    detail::specs_checker<null_handler> checker(
+        null_handler(), detail::mapped_type_constant<T, FormatContext>::value);
     checker.on_align(specs_.align);
     switch (specs_.sign) {
     case sign::none:
@@ -3053,109 +3571,40 @@ template <typename Char = char> class dynamic_formatter {
     }
     if (specs_.alt) checker.on_hash();
     if (specs_.precision >= 0) checker.end_precision();
-    using range = internal::output_range<typename FormatContext::iterator,
-                                         typename FormatContext::char_type>;
-    visit_format_arg(arg_formatter<range>(ctx, nullptr, &specs_),
-                     internal::make_arg<FormatContext>(val));
+    using af = detail::arg_formatter<typename FormatContext::iterator,
+                                     typename FormatContext::char_type>;
+    visit_format_arg(af(ctx, nullptr, &specs_),
+                     detail::make_arg<FormatContext>(val));
     return ctx.out();
   }
 
  private:
   template <typename Context> void handle_specs(Context& ctx) {
-    internal::handle_dynamic_spec<internal::width_checker>(
-        specs_.width, specs_.width_ref, ctx);
-    internal::handle_dynamic_spec<internal::precision_checker>(
+    detail::handle_dynamic_spec<detail::width_checker>(specs_.width,
+                                                       specs_.width_ref, ctx);
+    detail::handle_dynamic_spec<detail::precision_checker>(
         specs_.precision, specs_.precision_ref, ctx);
   }
 
-  internal::dynamic_format_specs<Char> specs_;
+  detail::dynamic_format_specs<Char> specs_;
   const Char* format_str_;
 };
 
-template <typename Range, typename Char>
-typename basic_format_context<Range, Char>::format_arg
-basic_format_context<Range, Char>::arg(basic_string_view<char_type> name) {
-  map_.init(args_);
-  format_arg arg = map_.find(name);
-  if (arg.type() == internal::none_type) this->on_error("argument not found");
-  return arg;
-}
-
 template <typename Char, typename ErrorHandler>
 FMT_CONSTEXPR void advance_to(
     basic_format_parse_context<Char, ErrorHandler>& ctx, const Char* p) {
   ctx.advance_to(ctx.begin() + (p - &*ctx.begin()));
 }
 
-template <typename ArgFormatter, typename Char, typename Context>
-struct format_handler : internal::error_handler {
-  using range = typename ArgFormatter::range;
-
-  format_handler(range r, basic_string_view<Char> str,
-                 basic_format_args<Context> format_args,
-                 internal::locale_ref loc)
-      : parse_context(str), context(r.begin(), format_args, loc) {}
-
-  void on_text(const Char* begin, const Char* end) {
-    auto size = internal::to_unsigned(end - begin);
-    auto out = context.out();
-    auto&& it = internal::reserve(out, size);
-    it = std::copy_n(begin, size, it);
-    context.advance_to(out);
-  }
-
-  void get_arg(int id) { arg = internal::get_arg(context, id); }
-
-  void on_arg_id() { get_arg(parse_context.next_arg_id()); }
-  void on_arg_id(int id) {
-    parse_context.check_arg_id(id);
-    get_arg(id);
-  }
-  void on_arg_id(basic_string_view<Char> id) { arg = context.arg(id); }
-
-  void on_replacement_field(const Char* p) {
-    advance_to(parse_context, p);
-    context.advance_to(
-        visit_format_arg(ArgFormatter(context, &parse_context), arg));
-  }
-
-  const Char* on_format_specs(const Char* begin, const Char* end) {
-    advance_to(parse_context, begin);
-    internal::custom_formatter<Context> f(parse_context, context);
-    if (visit_format_arg(f, arg)) return parse_context.begin();
-    basic_format_specs<Char> specs;
-    using internal::specs_handler;
-    using parse_context_t = basic_format_parse_context<Char>;
-    internal::specs_checker<specs_handler<parse_context_t, Context>> handler(
-        specs_handler<parse_context_t, Context>(specs, parse_context, context),
-        arg.type());
-    begin = parse_format_specs(begin, end, handler);
-    if (begin == end || *begin != '}') on_error("missing '}' in format string");
-    advance_to(parse_context, begin);
-    context.advance_to(
-        visit_format_arg(ArgFormatter(context, &parse_context, &specs), arg));
-    return begin;
-  }
-
-  basic_format_parse_context<Char> parse_context;
-  Context context;
-  basic_format_arg<Context> arg;
-};
+/**
+  \rst
+  Converts ``p`` to ``const void*`` for pointer formatting.
 
-/** Formats arguments and writes the output to the range. */
-template <typename ArgFormatter, typename Char, typename Context>
-typename Context::iterator vformat_to(
-    typename ArgFormatter::range out, basic_string_view<Char> format_str,
-    basic_format_args<Context> args,
-    internal::locale_ref loc = internal::locale_ref()) {
-  format_handler<ArgFormatter, Char, Context> h(out, format_str, args, loc);
-  internal::parse_format_string<false>(format_str, h);
-  return h.context.out();
-}
+  **Example**::
 
-// Casts ``p`` to ``const void*`` for pointer formatting.
-// Example:
-//   auto s = format("{}", ptr(p));
+    auto s = fmt::format("{}", fmt::ptr(p));
+  \endrst
+ */
 template <typename T> inline const void* ptr(const T* p) { return p; }
 template <typename T> inline const void* ptr(const std::unique_ptr<T>& p) {
   return p.get();
@@ -3164,19 +3613,55 @@ template <typename T> inline const void* ptr(const std::shared_ptr<T>& p) {
   return p.get();
 }
 
-template <typename It, typename Char> struct arg_join : internal::view {
+class bytes {
+ private:
+  string_view data_;
+  friend struct formatter<bytes>;
+
+ public:
+  explicit bytes(string_view data) : data_(data) {}
+};
+
+template <> struct formatter<bytes> {
+ private:
+  detail::dynamic_format_specs<char> specs_;
+
+ public:
+  template <typename ParseContext>
+  FMT_CONSTEXPR auto parse(ParseContext& ctx) -> decltype(ctx.begin()) {
+    using handler_type = detail::dynamic_specs_handler<ParseContext>;
+    detail::specs_checker<handler_type> handler(handler_type(specs_, ctx),
+                                                detail::type::string_type);
+    auto it = parse_format_specs(ctx.begin(), ctx.end(), handler);
+    detail::check_string_type_spec(specs_.type, ctx.error_handler());
+    return it;
+  }
+
+  template <typename FormatContext>
+  auto format(bytes b, FormatContext& ctx) -> decltype(ctx.out()) {
+    detail::handle_dynamic_spec<detail::width_checker>(specs_.width,
+                                                       specs_.width_ref, ctx);
+    detail::handle_dynamic_spec<detail::precision_checker>(
+        specs_.precision, specs_.precision_ref, ctx);
+    return detail::write_bytes(ctx.out(), b.data_, specs_);
+  }
+};
+
+template <typename It, typename Sentinel, typename Char>
+struct arg_join : detail::view {
   It begin;
-  It end;
+  Sentinel end;
   basic_string_view<Char> sep;
 
-  arg_join(It b, It e, basic_string_view<Char> s) : begin(b), end(e), sep(s) {}
+  arg_join(It b, Sentinel e, basic_string_view<Char> s)
+      : begin(b), end(e), sep(s) {}
 };
 
-template <typename It, typename Char>
-struct formatter<arg_join<It, Char>, Char>
+template <typename It, typename Sentinel, typename Char>
+struct formatter<arg_join<It, Sentinel, Char>, Char>
     : formatter<typename std::iterator_traits<It>::value_type, Char> {
   template <typename FormatContext>
-  auto format(const arg_join<It, Char>& value, FormatContext& ctx)
+  auto format(const arg_join<It, Sentinel, Char>& value, FormatContext& ctx)
       -> decltype(ctx.out()) {
     using base = formatter<typename std::iterator_traits<It>::value_type, Char>;
     auto it = value.begin;
@@ -3197,13 +3682,13 @@ struct formatter<arg_join<It, Char>, Char>
   Returns an object that formats the iterator range `[begin, end)` with elements
   separated by `sep`.
  */
-template <typename It>
-arg_join<It, char> join(It begin, It end, string_view sep) {
+template <typename It, typename Sentinel>
+arg_join<It, Sentinel, char> join(It begin, Sentinel end, string_view sep) {
   return {begin, end, sep};
 }
 
-template <typename It>
-arg_join<It, wchar_t> join(It begin, It end, wstring_view sep) {
+template <typename It, typename Sentinel>
+arg_join<It, Sentinel, wchar_t> join(It begin, Sentinel end, wstring_view sep) {
   return {begin, end, sep};
 }
 
@@ -3216,24 +3701,28 @@ arg_join<It, wchar_t> join(It begin, It end, wstring_view sep) {
     std::vector<int> v = {1, 2, 3};
     fmt::print("{}", fmt::join(v, ", "));
     // Output: "1, 2, 3"
+
+  ``fmt::join`` applies passed format specifiers to the range elements::
+
+    fmt::print("{:02}", fmt::join(v, ", "));
+    // Output: "01, 02, 03"
   \endrst
  */
 template <typename Range>
-arg_join<internal::iterator_t<const Range>, char> join(const Range& range,
-                                                       string_view sep) {
+arg_join<detail::iterator_t<Range>, detail::sentinel_t<Range>, char> join(
+    Range&& range, string_view sep) {
   return join(std::begin(range), std::end(range), sep);
 }
 
 template <typename Range>
-arg_join<internal::iterator_t<const Range>, wchar_t> join(const Range& range,
-                                                          wstring_view sep) {
+arg_join<detail::iterator_t<Range>, detail::sentinel_t<Range>, wchar_t> join(
+    Range&& range, wstring_view sep) {
   return join(std::begin(range), std::end(range), sep);
 }
 
 /**
   \rst
   Converts *value* to ``std::string`` using the default format for type *T*.
-  It doesn't support user-defined types with custom formatters.
 
   **Example**::
 
@@ -3242,8 +3731,21 @@ arg_join<internal::iterator_t<const Range>, wchar_t> join(const Range& range,
     std::string answer = fmt::to_string(42);
   \endrst
  */
-template <typename T> inline std::string to_string(const T& value) {
-  return format("{}", value);
+template <typename T, FMT_ENABLE_IF(!std::is_integral<T>::value)>
+inline std::string to_string(const T& value) {
+  std::string result;
+  detail::write<char>(std::back_inserter(result), value);
+  return result;
+}
+
+template <typename T, FMT_ENABLE_IF(std::is_integral<T>::value)>
+inline std::string to_string(T value) {
+  // The buffer should be large enough to store the number including the sign or
+  // "false" for bool.
+  constexpr int max_size = detail::digits10<T>() + 2;
+  char buffer[max_size > 5 ? static_cast<unsigned>(max_size) : 5];
+  char* begin = buffer;
+  return std::string(begin, detail::write<char>(begin, value));
 }
 
 /**
@@ -3253,36 +3755,75 @@ template <typename T> inline std::wstring to_wstring(const T& value) {
   return format(L"{}", value);
 }
 
-template <typename Char, std::size_t SIZE>
+template <typename Char, size_t SIZE>
 std::basic_string<Char> to_string(const basic_memory_buffer<Char, SIZE>& buf) {
-  return std::basic_string<Char>(buf.data(), buf.size());
+  auto size = buf.size();
+  detail::assume(size < std::basic_string<Char>().max_size());
+  return std::basic_string<Char>(buf.data(), size);
 }
 
 template <typename Char>
-typename buffer_context<Char>::iterator internal::vformat_to(
-    internal::buffer<Char>& buf, basic_string_view<Char> format_str,
-    basic_format_args<buffer_context<Char>> args) {
-  using range = buffer_range<Char>;
-  return vformat_to<arg_formatter<range>>(buf, to_string_view(format_str),
-                                          args);
-}
+void detail::vformat_to(
+    detail::buffer<Char>& buf, basic_string_view<Char> format_str,
+    basic_format_args<buffer_context<type_identity_t<Char>>> args,
+    detail::locale_ref loc) {
+  using iterator = typename buffer_context<Char>::iterator;
+  auto out = buffer_appender<Char>(buf);
+  if (format_str.size() == 2 && equal2(format_str.data(), "{}")) {
+    auto arg = args.get(0);
+    if (!arg) error_handler().on_error("argument not found");
+    visit_format_arg(default_arg_formatter<iterator, Char>{out, args, loc},
+                     arg);
+    return;
+  }
+  format_handler<iterator, Char, buffer_context<Char>> h(
+      out, format_str, args, loc);
+  parse_format_string<false>(format_str, h);
+}
+
+#ifndef FMT_HEADER_ONLY
+extern template void detail::vformat_to(detail::buffer<char>&, string_view,
+                                        basic_format_args<format_context>,
+                                        detail::locale_ref);
+namespace detail {
+extern template FMT_API std::string grouping_impl<char>(locale_ref loc);
+extern template FMT_API std::string grouping_impl<wchar_t>(locale_ref loc);
+extern template FMT_API char thousands_sep_impl<char>(locale_ref loc);
+extern template FMT_API wchar_t thousands_sep_impl<wchar_t>(locale_ref loc);
+extern template FMT_API char decimal_point_impl(locale_ref loc);
+extern template FMT_API wchar_t decimal_point_impl(locale_ref loc);
+extern template int format_float<double>(double value, int precision,
+                                         float_specs specs, buffer<char>& buf);
+extern template int format_float<long double>(long double value, int precision,
+                                              float_specs specs,
+                                              buffer<char>& buf);
+int snprintf_float(float value, int precision, float_specs specs,
+                   buffer<char>& buf) = delete;
+extern template int snprintf_float<double>(double value, int precision,
+                                           float_specs specs,
+                                           buffer<char>& buf);
+extern template int snprintf_float<long double>(long double value,
+                                                int precision,
+                                                float_specs specs,
+                                                buffer<char>& buf);
+}  // namespace detail
+#endif
 
 template <typename S, typename Char = char_t<S>,
-          FMT_ENABLE_IF(internal::is_string<S>::value)>
-inline typename buffer_context<Char>::iterator vformat_to(
-    internal::buffer<Char>& buf, const S& format_str,
-    basic_format_args<buffer_context<Char>> args) {
-  return internal::vformat_to(buf, to_string_view(format_str), args);
+          FMT_ENABLE_IF(detail::is_string<S>::value)>
+inline void vformat_to(
+    detail::buffer<Char>& buf, const S& format_str,
+    basic_format_args<FMT_BUFFER_CONTEXT(type_identity_t<Char>)> args) {
+  return detail::vformat_to(buf, to_string_view(format_str), args);
 }
 
-template <typename S, typename... Args, std::size_t SIZE = inline_buffer_size,
-          typename Char = enable_if_t<internal::is_string<S>::value, char_t<S>>>
+template <typename S, typename... Args, size_t SIZE = inline_buffer_size,
+          typename Char = enable_if_t<detail::is_string<S>::value, char_t<S>>>
 inline typename buffer_context<Char>::iterator format_to(
     basic_memory_buffer<Char, SIZE>& buf, const S& format_str, Args&&... args) {
-  internal::check_format_string<Args...>(format_str);
-  using context = buffer_context<Char>;
-  return internal::vformat_to(buf, to_string_view(format_str),
-                              {make_format_args<context>(args...)});
+  const auto& vargs = fmt::make_args_checked<Args...>(format_str, args...);
+  detail::vformat_to(buf, to_string_view(format_str), vargs);
+  return detail::buffer_appender<Char>(buf);
 }
 
 template <typename OutputIt, typename Char = char>
@@ -3291,113 +3832,33 @@ using format_context_t = basic_format_context<OutputIt, Char>;
 template <typename OutputIt, typename Char = char>
 using format_args_t = basic_format_args<format_context_t<OutputIt, Char>>;
 
-template <typename S, typename OutputIt, typename... Args,
-          FMT_ENABLE_IF(
-              internal::is_output_iterator<OutputIt>::value &&
-              !internal::is_contiguous_back_insert_iterator<OutputIt>::value)>
-inline OutputIt vformat_to(OutputIt out, const S& format_str,
-                           format_args_t<OutputIt, char_t<S>> args) {
-  using range = internal::output_range<OutputIt, char_t<S>>;
-  return vformat_to<arg_formatter<range>>(range(out),
-                                          to_string_view(format_str), args);
-}
-
-/**
- \rst
- Formats arguments, writes the result to the output iterator ``out`` and returns
- the iterator past the end of the output range.
-
- **Example**::
-
-   std::vector<char> out;
-   fmt::format_to(std::back_inserter(out), "{}", 42);
- \endrst
- */
-template <typename OutputIt, typename S, typename... Args,
-          FMT_ENABLE_IF(
-              internal::is_output_iterator<OutputIt>::value &&
-              !internal::is_contiguous_back_insert_iterator<OutputIt>::value &&
-              internal::is_string<S>::value)>
-inline OutputIt format_to(OutputIt out, const S& format_str, Args&&... args) {
-  internal::check_format_string<Args...>(format_str);
-  using context = format_context_t<OutputIt, char_t<S>>;
-  return vformat_to(out, to_string_view(format_str),
-                    {make_format_args<context>(args...)});
-}
-
-template <typename OutputIt> struct format_to_n_result {
-  /** Iterator past the end of the output range. */
-  OutputIt out;
-  /** Total (not truncated) output size. */
-  std::size_t size;
-};
-
 template <typename OutputIt, typename Char = typename OutputIt::value_type>
-using format_to_n_context =
-    format_context_t<internal::truncating_iterator<OutputIt>, Char>;
+using format_to_n_context FMT_DEPRECATED_ALIAS = buffer_context<Char>;
 
 template <typename OutputIt, typename Char = typename OutputIt::value_type>
-using format_to_n_args = basic_format_args<format_to_n_context<OutputIt, Char>>;
+using format_to_n_args FMT_DEPRECATED_ALIAS =
+    basic_format_args<buffer_context<Char>>;
 
 template <typename OutputIt, typename Char, typename... Args>
-inline format_arg_store<format_to_n_context<OutputIt, Char>, Args...>
+FMT_DEPRECATED format_arg_store<buffer_context<Char>, Args...>
 make_format_to_n_args(const Args&... args) {
-  return format_arg_store<format_to_n_context<OutputIt, Char>, Args...>(
-      args...);
-}
-
-template <typename OutputIt, typename Char, typename... Args,
-          FMT_ENABLE_IF(internal::is_output_iterator<OutputIt>::value)>
-inline format_to_n_result<OutputIt> vformat_to_n(
-    OutputIt out, std::size_t n, basic_string_view<Char> format_str,
-    format_to_n_args<OutputIt, Char> args) {
-  auto it = vformat_to(internal::truncating_iterator<OutputIt>(out, n),
-                       format_str, args);
-  return {it.base(), it.count()};
-}
-
-/**
- \rst
- Formats arguments, writes up to ``n`` characters of the result to the output
- iterator ``out`` and returns the total output size and the iterator past the
- end of the output range.
- \endrst
- */
-template <typename OutputIt, typename S, typename... Args,
-          FMT_ENABLE_IF(internal::is_string<S>::value&&
-                            internal::is_output_iterator<OutputIt>::value)>
-inline format_to_n_result<OutputIt> format_to_n(OutputIt out, std::size_t n,
-                                                const S& format_str,
-                                                const Args&... args) {
-  internal::check_format_string<Args...>(format_str);
-  using context = format_to_n_context<OutputIt, char_t<S>>;
-  return vformat_to_n(out, n, to_string_view(format_str),
-                      {make_format_args<context>(args...)});
+  return format_arg_store<buffer_context<Char>, Args...>(args...);
 }
 
-template <typename Char>
-inline std::basic_string<Char> internal::vformat(
+template <typename Char, enable_if_t<(!std::is_same<Char, char>::value), int>>
+std::basic_string<Char> detail::vformat(
     basic_string_view<Char> format_str,
-    basic_format_args<buffer_context<Char>> args) {
+    basic_format_args<buffer_context<type_identity_t<Char>>> args) {
   basic_memory_buffer<Char> buffer;
-  internal::vformat_to(buffer, format_str, args);
+  detail::vformat_to(buffer, format_str, args);
   return to_string(buffer);
 }
 
-/**
-  Returns the number of characters in the output of
-  ``format(format_str, args...)``.
- */
-template <typename... Args>
-inline std::size_t formatted_size(string_view format_str, const Args&... args) {
-  return format_to(internal::counting_iterator(), format_str, args...).count();
-}
-
 template <typename Char, FMT_ENABLE_IF(std::is_same<Char, wchar_t>::value)>
 void vprint(std::FILE* f, basic_string_view<Char> format_str,
             wformat_args args) {
   wmemory_buffer buffer;
-  internal::vformat_to(buffer, format_str, args);
+  detail::vformat_to(buffer, format_str, args);
   buffer.push_back(L'\0');
   if (std::fputws(buffer.data(), f) == -1)
     FMT_THROW(system_error(errno, "cannot write to file"));
@@ -3409,19 +3870,15 @@ void vprint(basic_string_view<Char> format_str, wformat_args args) {
 }
 
 #if FMT_USE_USER_DEFINED_LITERALS
-namespace internal {
+namespace detail {
 
 #  if FMT_USE_UDL_TEMPLATE
 template <typename Char, Char... CHARS> class udl_formatter {
  public:
   template <typename... Args>
   std::basic_string<Char> operator()(Args&&... args) const {
-    FMT_CONSTEXPR_DECL Char s[] = {CHARS..., '\0'};
-    FMT_CONSTEXPR_DECL bool invalid_format =
-        do_check_format_string<Char, error_handler, remove_cvref_t<Args>...>(
-            basic_string_view<Char>(s, sizeof...(CHARS)));
-    (void)invalid_format;
-    return format(s, std::forward<Args>(args)...);
+    static FMT_CONSTEXPR_DECL Char s[] = {CHARS..., '\0'};
+    return format(FMT_STRING(s), std::forward<Args>(args)...);
   }
 };
 #  else
@@ -3436,23 +3893,23 @@ template <typename Char> struct udl_formatter {
 #  endif  // FMT_USE_UDL_TEMPLATE
 
 template <typename Char> struct udl_arg {
-  basic_string_view<Char> str;
+  const Char* str;
 
-  template <typename T> named_arg<T, Char> operator=(T&& value) const {
+  template <typename T> named_arg<Char, T> operator=(T&& value) const {
     return {str, std::forward<T>(value)};
   }
 };
-
-}  // namespace internal
+}  // namespace detail
 
 inline namespace literals {
 #  if FMT_USE_UDL_TEMPLATE
 #    pragma GCC diagnostic push
+#    pragma GCC diagnostic ignored "-Wpedantic"
 #    if FMT_CLANG_VERSION
 #      pragma GCC diagnostic ignored "-Wgnu-string-literal-operator-template"
 #    endif
 template <typename Char, Char... CHARS>
-FMT_CONSTEXPR internal::udl_formatter<Char, CHARS...> operator""_format() {
+FMT_CONSTEXPR detail::udl_formatter<Char, CHARS...> operator""_format() {
   return {};
 }
 #    pragma GCC diagnostic pop
@@ -3467,12 +3924,12 @@ FMT_CONSTEXPR internal::udl_formatter<Char, CHARS...> operator""_format() {
     std::string message = "The answer is {}"_format(42);
   \endrst
  */
-FMT_CONSTEXPR internal::udl_formatter<char> operator"" _format(const char* s,
-                                                               std::size_t n) {
+FMT_CONSTEXPR detail::udl_formatter<char> operator"" _format(const char* s,
+                                                             size_t n) {
   return {{s, n}};
 }
-FMT_CONSTEXPR internal::udl_formatter<wchar_t> operator"" _format(
-    const wchar_t* s, std::size_t n) {
+FMT_CONSTEXPR detail::udl_formatter<wchar_t> operator"" _format(
+    const wchar_t* s, size_t n) {
   return {{s, n}};
 }
 #  endif  // FMT_USE_UDL_TEMPLATE
@@ -3487,50 +3944,16 @@ FMT_CONSTEXPR internal::udl_formatter<wchar_t> operator"" _format(
     fmt::print("Elapsed time: {s:.2f} seconds", "s"_a=1.23);
   \endrst
  */
-FMT_CONSTEXPR internal::udl_arg<char> operator"" _a(const char* s,
-                                                    std::size_t n) {
-  return {{s, n}};
+FMT_CONSTEXPR detail::udl_arg<char> operator"" _a(const char* s, size_t) {
+  return {s};
 }
-FMT_CONSTEXPR internal::udl_arg<wchar_t> operator"" _a(const wchar_t* s,
-                                                       std::size_t n) {
-  return {{s, n}};
+FMT_CONSTEXPR detail::udl_arg<wchar_t> operator"" _a(const wchar_t* s, size_t) {
+  return {s};
 }
 }  // namespace literals
 #endif  // FMT_USE_USER_DEFINED_LITERALS
 FMT_END_NAMESPACE
 
-#define FMT_STRING_IMPL(s, ...)                                         \
-  [] {                                                                  \
-    struct str : fmt::compile_string {                                  \
-      using char_type = typename std::remove_cv<std::remove_pointer<    \
-          typename std::decay<decltype(s)>::type>::type>::type;         \
-      __VA_ARGS__ FMT_CONSTEXPR                                         \
-      operator fmt::basic_string_view<char_type>() const {              \
-        return {s, sizeof(s) / sizeof(char_type) - 1};                  \
-      }                                                                 \
-    } result;                                                           \
-    /* Suppress Qt Creator warning about unused operator. */            \
-    (void)static_cast<fmt::basic_string_view<typename str::char_type>>( \
-        result);                                                        \
-    return result;                                                      \
-  }()
-
-/**
-  \rst
-  Constructs a compile-time format string.
-
-  **Example**::
-
-    // A compile-time error because 'd' is an invalid specifier for strings.
-    std::string s = format(FMT_STRING("{:d}"), "foo");
-  \endrst
- */
-#define FMT_STRING(s) FMT_STRING_IMPL(s, )
-
-#if defined(FMT_STRING_ALIAS) && FMT_STRING_ALIAS
-#  define fmt(s) FMT_STRING_IMPL(s, [[deprecated]])
-#endif
-
 #ifdef FMT_HEADER_ONLY
 #  define FMT_FUNC inline
 #  include "format-inl.h"
diff --git a/Externals/fmt/include/fmt/locale.h b/Externals/fmt/include/fmt/locale.h
index 7c13656e4fa8..517f65054f27 100755
--- a/Externals/fmt/include/fmt/locale.h
+++ b/Externals/fmt/include/fmt/locale.h
@@ -9,67 +9,54 @@
 #define FMT_LOCALE_H_
 
 #include <locale>
+
 #include "format.h"
 
 FMT_BEGIN_NAMESPACE
 
-namespace internal {
-template <typename Char>
-typename buffer_context<Char>::iterator vformat_to(
-    const std::locale& loc, buffer<Char>& buf,
-    basic_string_view<Char> format_str,
-    basic_format_args<buffer_context<Char>> args) {
-  using range = buffer_range<Char>;
-  return vformat_to<arg_formatter<range>>(buf, to_string_view(format_str), args,
-                                          internal::locale_ref(loc));
-}
-
+namespace detail {
 template <typename Char>
-std::basic_string<Char> vformat(const std::locale& loc,
-                                basic_string_view<Char> format_str,
-                                basic_format_args<buffer_context<Char>> args) {
+std::basic_string<Char> vformat(
+    const std::locale& loc, basic_string_view<Char> format_str,
+    basic_format_args<buffer_context<type_identity_t<Char>>> args) {
   basic_memory_buffer<Char> buffer;
-  internal::vformat_to(loc, buffer, format_str, args);
+  detail::vformat_to(buffer, format_str, args, detail::locale_ref(loc));
   return fmt::to_string(buffer);
 }
-}  // namespace internal
+}  // namespace detail
 
 template <typename S, typename Char = char_t<S>>
 inline std::basic_string<Char> vformat(
     const std::locale& loc, const S& format_str,
-    basic_format_args<buffer_context<Char>> args) {
-  return internal::vformat(loc, to_string_view(format_str), args);
+    basic_format_args<buffer_context<type_identity_t<Char>>> args) {
+  return detail::vformat(loc, to_string_view(format_str), args);
 }
 
 template <typename S, typename... Args, typename Char = char_t<S>>
 inline std::basic_string<Char> format(const std::locale& loc,
                                       const S& format_str, Args&&... args) {
-  return internal::vformat(
-      loc, to_string_view(format_str),
-      {internal::make_args_checked<Args...>(format_str, args...)});
+  return detail::vformat(loc, to_string_view(format_str),
+                         fmt::make_args_checked<Args...>(format_str, args...));
 }
 
 template <typename S, typename OutputIt, typename... Args,
-          typename Char = enable_if_t<
-              internal::is_output_iterator<OutputIt>::value, char_t<S>>>
-inline OutputIt vformat_to(OutputIt out, const std::locale& loc,
-                           const S& format_str,
-                           format_args_t<OutputIt, Char> args) {
-  using range = internal::output_range<OutputIt, Char>;
-  return vformat_to<arg_formatter<range>>(
-      range(out), to_string_view(format_str), args, internal::locale_ref(loc));
+          typename Char = char_t<S>,
+          FMT_ENABLE_IF(detail::is_output_iterator<OutputIt, Char>::value)>
+inline OutputIt vformat_to(
+    OutputIt out, const std::locale& loc, const S& format_str,
+    basic_format_args<buffer_context<type_identity_t<Char>>> args) {
+  decltype(detail::get_buffer<Char>(out)) buf(detail::get_buffer_init(out));
+  vformat_to(buf, to_string_view(format_str), args, detail::locale_ref(loc));
+  return detail::get_iterator(buf);
 }
 
 template <typename OutputIt, typename S, typename... Args,
-          FMT_ENABLE_IF(internal::is_output_iterator<OutputIt>::value&&
-                            internal::is_string<S>::value)>
+          typename Char = char_t<S>,
+          FMT_ENABLE_IF(detail::is_output_iterator<OutputIt, Char>::value)>
 inline OutputIt format_to(OutputIt out, const std::locale& loc,
                           const S& format_str, Args&&... args) {
-  internal::check_format_string<Args...>(format_str);
-  using context = format_context_t<OutputIt, char_t<S>>;
-  format_arg_store<context, Args...> as{args...};
-  return vformat_to(out, loc, to_string_view(format_str),
-                    basic_format_args<context>(as));
+  const auto& vargs = fmt::make_args_checked<Args...>(format_str, args...);
+  return vformat_to(out, loc, to_string_view(format_str), vargs);
 }
 
 FMT_END_NAMESPACE
diff --git a/Externals/fmt/include/fmt/os.h b/Externals/fmt/include/fmt/os.h
new file mode 100644
index 000000000000..881510065a5e
--- /dev/null
+++ b/Externals/fmt/include/fmt/os.h
@@ -0,0 +1,480 @@
+// Formatting library for C++ - optional OS-specific functionality
+//
+// Copyright (c) 2012 - present, Victor Zverovich
+// All rights reserved.
+//
+// For the license information refer to format.h.
+
+#ifndef FMT_OS_H_
+#define FMT_OS_H_
+
+#if defined(__MINGW32__) || defined(__CYGWIN__)
+// Workaround MinGW bug https://sourceforge.net/p/mingw/bugs/2024/.
+#  undef __STRICT_ANSI__
+#endif
+
+#include <cerrno>
+#include <clocale>  // for locale_t
+#include <cstddef>
+#include <cstdio>
+#include <cstdlib>  // for strtod_l
+
+#if defined __APPLE__ || defined(__FreeBSD__)
+#  include <xlocale.h>  // for LC_NUMERIC_MASK on OS X
+#endif
+
+#include "format.h"
+
+// UWP doesn't provide _pipe.
+#if FMT_HAS_INCLUDE("winapifamily.h")
+#  include <winapifamily.h>
+#endif
+#if (FMT_HAS_INCLUDE(<fcntl.h>) || defined(__APPLE__) || \
+     defined(__linux__)) &&                              \
+    (!defined(WINAPI_FAMILY) || (WINAPI_FAMILY == WINAPI_FAMILY_DESKTOP_APP))
+#  include <fcntl.h>  // for O_RDONLY
+#  define FMT_USE_FCNTL 1
+#else
+#  define FMT_USE_FCNTL 0
+#endif
+
+#ifndef FMT_POSIX
+#  if defined(_WIN32) && !defined(__MINGW32__)
+// Fix warnings about deprecated symbols.
+#    define FMT_POSIX(call) _##call
+#  else
+#    define FMT_POSIX(call) call
+#  endif
+#endif
+
+// Calls to system functions are wrapped in FMT_SYSTEM for testability.
+#ifdef FMT_SYSTEM
+#  define FMT_POSIX_CALL(call) FMT_SYSTEM(call)
+#else
+#  define FMT_SYSTEM(call) ::call
+#  ifdef _WIN32
+// Fix warnings about deprecated symbols.
+#    define FMT_POSIX_CALL(call) ::_##call
+#  else
+#    define FMT_POSIX_CALL(call) ::call
+#  endif
+#endif
+
+// Retries the expression while it evaluates to error_result and errno
+// equals to EINTR.
+#ifndef _WIN32
+#  define FMT_RETRY_VAL(result, expression, error_result) \
+    do {                                                  \
+      (result) = (expression);                            \
+    } while ((result) == (error_result) && errno == EINTR)
+#else
+#  define FMT_RETRY_VAL(result, expression, error_result) result = (expression)
+#endif
+
+#define FMT_RETRY(result, expression) FMT_RETRY_VAL(result, expression, -1)
+
+FMT_BEGIN_NAMESPACE
+
+/**
+  \rst
+  A reference to a null-terminated string. It can be constructed from a C
+  string or ``std::string``.
+
+  You can use one of the following type aliases for common character types:
+
+  +---------------+-----------------------------+
+  | Type          | Definition                  |
+  +===============+=============================+
+  | cstring_view  | basic_cstring_view<char>    |
+  +---------------+-----------------------------+
+  | wcstring_view | basic_cstring_view<wchar_t> |
+  +---------------+-----------------------------+
+
+  This class is most useful as a parameter type to allow passing
+  different types of strings to a function, for example::
+
+    template <typename... Args>
+    std::string format(cstring_view format_str, const Args & ... args);
+
+    format("{}", 42);
+    format(std::string("{}"), 42);
+  \endrst
+ */
+template <typename Char> class basic_cstring_view {
+ private:
+  const Char* data_;
+
+ public:
+  /** Constructs a string reference object from a C string. */
+  basic_cstring_view(const Char* s) : data_(s) {}
+
+  /**
+    \rst
+    Constructs a string reference from an ``std::string`` object.
+    \endrst
+   */
+  basic_cstring_view(const std::basic_string<Char>& s) : data_(s.c_str()) {}
+
+  /** Returns the pointer to a C string. */
+  const Char* c_str() const { return data_; }
+};
+
+using cstring_view = basic_cstring_view<char>;
+using wcstring_view = basic_cstring_view<wchar_t>;
+
+// An error code.
+class error_code {
+ private:
+  int value_;
+
+ public:
+  explicit error_code(int value = 0) FMT_NOEXCEPT : value_(value) {}
+
+  int get() const FMT_NOEXCEPT { return value_; }
+};
+
+#ifdef _WIN32
+namespace detail {
+// A converter from UTF-16 to UTF-8.
+// It is only provided for Windows since other systems support UTF-8 natively.
+class utf16_to_utf8 {
+ private:
+  memory_buffer buffer_;
+
+ public:
+  utf16_to_utf8() {}
+  FMT_API explicit utf16_to_utf8(wstring_view s);
+  operator string_view() const { return string_view(&buffer_[0], size()); }
+  size_t size() const { return buffer_.size() - 1; }
+  const char* c_str() const { return &buffer_[0]; }
+  std::string str() const { return std::string(&buffer_[0], size()); }
+
+  // Performs conversion returning a system error code instead of
+  // throwing exception on conversion error. This method may still throw
+  // in case of memory allocation error.
+  FMT_API int convert(wstring_view s);
+};
+
+FMT_API void format_windows_error(buffer<char>& out, int error_code,
+                                  string_view message) FMT_NOEXCEPT;
+}  // namespace detail
+
+/** A Windows error. */
+class windows_error : public system_error {
+ private:
+  FMT_API void init(int error_code, string_view format_str, format_args args);
+
+ public:
+  /**
+   \rst
+   Constructs a :class:`fmt::windows_error` object with the description
+   of the form
+
+   .. parsed-literal::
+     *<message>*: *<system-message>*
+
+   where *<message>* is the formatted message and *<system-message>* is the
+   system message corresponding to the error code.
+   *error_code* is a Windows error code as given by ``GetLastError``.
+   If *error_code* is not a valid error code such as -1, the system message
+   will look like "error -1".
+
+   **Example**::
+
+     // This throws a windows_error with the description
+     //   cannot open file 'madeup': The system cannot find the file specified.
+     // or similar (system message may vary).
+     const char *filename = "madeup";
+     LPOFSTRUCT of = LPOFSTRUCT();
+     HFILE file = OpenFile(filename, &of, OF_READ);
+     if (file == HFILE_ERROR) {
+       throw fmt::windows_error(GetLastError(),
+                                "cannot open file '{}'", filename);
+     }
+   \endrst
+  */
+  template <typename... Args>
+  windows_error(int error_code, string_view message, const Args&... args) {
+    init(error_code, message, make_format_args(args...));
+  }
+};
+
+// Reports a Windows error without throwing an exception.
+// Can be used to report errors from destructors.
+FMT_API void report_windows_error(int error_code,
+                                  string_view message) FMT_NOEXCEPT;
+#endif  // _WIN32
+
+// A buffered file.
+class buffered_file {
+ private:
+  FILE* file_;
+
+  friend class file;
+
+  explicit buffered_file(FILE* f) : file_(f) {}
+
+ public:
+  buffered_file(const buffered_file&) = delete;
+  void operator=(const buffered_file&) = delete;
+
+  // Constructs a buffered_file object which doesn't represent any file.
+  buffered_file() FMT_NOEXCEPT : file_(nullptr) {}
+
+  // Destroys the object closing the file it represents if any.
+  FMT_API ~buffered_file() FMT_NOEXCEPT;
+
+ public:
+  buffered_file(buffered_file&& other) FMT_NOEXCEPT : file_(other.file_) {
+    other.file_ = nullptr;
+  }
+
+  buffered_file& operator=(buffered_file&& other) {
+    close();
+    file_ = other.file_;
+    other.file_ = nullptr;
+    return *this;
+  }
+
+  // Opens a file.
+  FMT_API buffered_file(cstring_view filename, cstring_view mode);
+
+  // Closes the file.
+  FMT_API void close();
+
+  // Returns the pointer to a FILE object representing this file.
+  FILE* get() const FMT_NOEXCEPT { return file_; }
+
+  // We place parentheses around fileno to workaround a bug in some versions
+  // of MinGW that define fileno as a macro.
+  FMT_API int(fileno)() const;
+
+  void vprint(string_view format_str, format_args args) {
+    fmt::vprint(file_, format_str, args);
+  }
+
+  template <typename... Args>
+  inline void print(string_view format_str, const Args&... args) {
+    vprint(format_str, make_format_args(args...));
+  }
+};
+
+#if FMT_USE_FCNTL
+// A file. Closed file is represented by a file object with descriptor -1.
+// Methods that are not declared with FMT_NOEXCEPT may throw
+// fmt::system_error in case of failure. Note that some errors such as
+// closing the file multiple times will cause a crash on Windows rather
+// than an exception. You can get standard behavior by overriding the
+// invalid parameter handler with _set_invalid_parameter_handler.
+class file {
+ private:
+  int fd_;  // File descriptor.
+
+  // Constructs a file object with a given descriptor.
+  explicit file(int fd) : fd_(fd) {}
+
+ public:
+  // Possible values for the oflag argument to the constructor.
+  enum {
+    RDONLY = FMT_POSIX(O_RDONLY),  // Open for reading only.
+    WRONLY = FMT_POSIX(O_WRONLY),  // Open for writing only.
+    RDWR = FMT_POSIX(O_RDWR),      // Open for reading and writing.
+    CREATE = FMT_POSIX(O_CREAT),   // Create if the file doesn't exist.
+    APPEND = FMT_POSIX(O_APPEND)   // Open in append mode.
+  };
+
+  // Constructs a file object which doesn't represent any file.
+  file() FMT_NOEXCEPT : fd_(-1) {}
+
+  // Opens a file and constructs a file object representing this file.
+  FMT_API file(cstring_view path, int oflag);
+
+ public:
+  file(const file&) = delete;
+  void operator=(const file&) = delete;
+
+  file(file&& other) FMT_NOEXCEPT : fd_(other.fd_) { other.fd_ = -1; }
+
+  file& operator=(file&& other) FMT_NOEXCEPT {
+    close();
+    fd_ = other.fd_;
+    other.fd_ = -1;
+    return *this;
+  }
+
+  // Destroys the object closing the file it represents if any.
+  FMT_API ~file() FMT_NOEXCEPT;
+
+  // Returns the file descriptor.
+  int descriptor() const FMT_NOEXCEPT { return fd_; }
+
+  // Closes the file.
+  FMT_API void close();
+
+  // Returns the file size. The size has signed type for consistency with
+  // stat::st_size.
+  FMT_API long long size() const;
+
+  // Attempts to read count bytes from the file into the specified buffer.
+  FMT_API size_t read(void* buffer, size_t count);
+
+  // Attempts to write count bytes from the specified buffer to the file.
+  FMT_API size_t write(const void* buffer, size_t count);
+
+  // Duplicates a file descriptor with the dup function and returns
+  // the duplicate as a file object.
+  FMT_API static file dup(int fd);
+
+  // Makes fd be the copy of this file descriptor, closing fd first if
+  // necessary.
+  FMT_API void dup2(int fd);
+
+  // Makes fd be the copy of this file descriptor, closing fd first if
+  // necessary.
+  FMT_API void dup2(int fd, error_code& ec) FMT_NOEXCEPT;
+
+  // Creates a pipe setting up read_end and write_end file objects for reading
+  // and writing respectively.
+  FMT_API static void pipe(file& read_end, file& write_end);
+
+  // Creates a buffered_file object associated with this file and detaches
+  // this file object from the file.
+  FMT_API buffered_file fdopen(const char* mode);
+};
+
+// Returns the memory page size.
+long getpagesize();
+
+namespace detail {
+
+struct buffer_size {
+  size_t value = 0;
+  buffer_size operator=(size_t val) const {
+    auto bs = buffer_size();
+    bs.value = val;
+    return bs;
+  }
+};
+
+struct ostream_params {
+  int oflag = file::WRONLY | file::CREATE;
+  size_t buffer_size = BUFSIZ > 32768 ? BUFSIZ : 32768;
+
+  ostream_params() {}
+
+  template <typename... T>
+  ostream_params(T... params, int oflag) : ostream_params(params...) {
+    this->oflag = oflag;
+  }
+
+  template <typename... T>
+  ostream_params(T... params, detail::buffer_size bs)
+      : ostream_params(params...) {
+    this->buffer_size = bs.value;
+  }
+};
+}  // namespace detail
+
+static constexpr detail::buffer_size buffer_size;
+
+// A fast output stream which is not thread-safe.
+class ostream final : private detail::buffer<char> {
+ private:
+  file file_;
+
+  void flush() {
+    if (size() == 0) return;
+    file_.write(data(), size());
+    clear();
+  }
+
+  void grow(size_t) final;
+
+  ostream(cstring_view path, const detail::ostream_params& params)
+      : file_(path, params.oflag) {
+    set(new char[params.buffer_size], params.buffer_size);
+  }
+
+ public:
+  ostream(ostream&& other)
+      : detail::buffer<char>(other.data(), other.size(), other.capacity()),
+        file_(std::move(other.file_)) {
+    other.set(nullptr, 0);
+  }
+  ~ostream() {
+    flush();
+    delete[] data();
+  }
+
+  template <typename... T>
+  friend ostream output_file(cstring_view path, T... params);
+
+  void close() {
+    flush();
+    file_.close();
+  }
+
+  template <typename S, typename... Args>
+  void print(const S& format_str, const Args&... args) {
+    format_to(detail::buffer_appender<char>(*this), format_str, args...);
+  }
+};
+
+/**
+  Opens a file for writing. Supported parameters passed in `params`:
+  * ``<integer>``: Output flags (``file::WRONLY | file::CREATE`` by default)
+  * ``buffer_size=<integer>``: Output buffer size
+ */
+template <typename... T>
+inline ostream output_file(cstring_view path, T... params) {
+  return {path, detail::ostream_params(params...)};
+}
+#endif  // FMT_USE_FCNTL
+
+#ifdef FMT_LOCALE
+// A "C" numeric locale.
+class locale {
+ private:
+#  ifdef _WIN32
+  using locale_t = _locale_t;
+
+  static void freelocale(locale_t loc) { _free_locale(loc); }
+
+  static double strtod_l(const char* nptr, char** endptr, _locale_t loc) {
+    return _strtod_l(nptr, endptr, loc);
+  }
+#  endif
+
+  locale_t locale_;
+
+ public:
+  using type = locale_t;
+  locale(const locale&) = delete;
+  void operator=(const locale&) = delete;
+
+  locale() {
+#  ifndef _WIN32
+    locale_ = FMT_SYSTEM(newlocale(LC_NUMERIC_MASK, "C", nullptr));
+#  else
+    locale_ = _create_locale(LC_NUMERIC, "C");
+#  endif
+    if (!locale_) FMT_THROW(system_error(errno, "cannot create locale"));
+  }
+  ~locale() { freelocale(locale_); }
+
+  type get() const { return locale_; }
+
+  // Converts string to floating-point number and advances str past the end
+  // of the parsed input.
+  double strtod(const char*& str) const {
+    char* end = nullptr;
+    double result = strtod_l(str, &end, locale_);
+    str = end;
+    return result;
+  }
+};
+using Locale FMT_DEPRECATED_ALIAS = locale;
+#endif  // FMT_LOCALE
+FMT_END_NAMESPACE
+
+#endif  // FMT_OS_H_
diff --git a/Externals/fmt/include/fmt/ostream.h b/Externals/fmt/include/fmt/ostream.h
index 72d078b20c61..29c58ec13b15 100755
--- a/Externals/fmt/include/fmt/ostream.h
+++ b/Externals/fmt/include/fmt/ostream.h
@@ -9,10 +9,15 @@
 #define FMT_OSTREAM_H_
 
 #include <ostream>
+
 #include "format.h"
 
 FMT_BEGIN_NAMESPACE
-namespace internal {
+
+template <typename Char> class basic_printf_parse_context;
+template <typename OutputIt, typename Char> class basic_printf_context;
+
+namespace detail {
 
 template <class Char> class formatbuf : public std::basic_streambuf<Char> {
  private:
@@ -44,17 +49,27 @@ template <class Char> class formatbuf : public std::basic_streambuf<Char> {
   }
 };
 
+struct converter {
+  template <typename T, FMT_ENABLE_IF(is_integral<T>::value)> converter(T);
+};
+
 template <typename Char> struct test_stream : std::basic_ostream<Char> {
  private:
-  // Hide all operator<< from std::basic_ostream<Char>.
-  void_t<> operator<<(null<>);
-  void_t<> operator<<(const Char*);
-
-  template <typename T, FMT_ENABLE_IF(std::is_convertible<T, int>::value &&
-                                      !std::is_enum<T>::value)>
-  void_t<> operator<<(T);
+  void_t<> operator<<(converter);
 };
 
+// Hide insertion operators for built-in types.
+template <typename Char, typename Traits>
+void_t<> operator<<(std::basic_ostream<Char, Traits>&, Char);
+template <typename Char, typename Traits>
+void_t<> operator<<(std::basic_ostream<Char, Traits>&, char);
+template <typename Traits>
+void_t<> operator<<(std::basic_ostream<char, Traits>&, char);
+template <typename Traits>
+void_t<> operator<<(std::basic_ostream<char, Traits>&, signed char);
+template <typename Traits>
+void_t<> operator<<(std::basic_ostream<char, Traits>&, unsigned char);
+
 // Checks if T has a user-defined operator<< (e.g. not a member of
 // std::ostream).
 template <typename T, typename Char> class is_streamable {
@@ -75,7 +90,7 @@ template <typename T, typename Char> class is_streamable {
 
 // Write the content of buf to os.
 template <typename Char>
-void write(std::basic_ostream<Char>& os, buffer<Char>& buf) {
+void write_buffer(std::basic_ostream<Char>& os, buffer<Char>& buf) {
   const Char* buf_data = buf.data();
   using unsigned_streamsize = std::make_unsigned<std::streamsize>::type;
   unsigned_streamsize size = buf.size();
@@ -93,32 +108,53 @@ void format_value(buffer<Char>& buf, const T& value,
                   locale_ref loc = locale_ref()) {
   formatbuf<Char> format_buf(buf);
   std::basic_ostream<Char> output(&format_buf);
+#if !defined(FMT_STATIC_THOUSANDS_SEPARATOR)
   if (loc) output.imbue(loc.get<std::locale>());
-  output.exceptions(std::ios_base::failbit | std::ios_base::badbit);
+#endif
   output << value;
-  buf.resize(buf.size());
+  output.exceptions(std::ios_base::failbit | std::ios_base::badbit);
+  buf.try_resize(buf.size());
 }
 
 // Formats an object of type T that has an overloaded ostream operator<<.
 template <typename T, typename Char>
 struct fallback_formatter<T, Char, enable_if_t<is_streamable<T, Char>::value>>
-    : formatter<basic_string_view<Char>, Char> {
-  template <typename Context>
-  auto format(const T& value, Context& ctx) -> decltype(ctx.out()) {
+    : private formatter<basic_string_view<Char>, Char> {
+  FMT_CONSTEXPR auto parse(basic_format_parse_context<Char>& ctx)
+      -> decltype(ctx.begin()) {
+    return formatter<basic_string_view<Char>, Char>::parse(ctx);
+  }
+  template <typename ParseCtx,
+            FMT_ENABLE_IF(std::is_same<
+                          ParseCtx, basic_printf_parse_context<Char>>::value)>
+  auto parse(ParseCtx& ctx) -> decltype(ctx.begin()) {
+    return ctx.begin();
+  }
+
+  template <typename OutputIt>
+  auto format(const T& value, basic_format_context<OutputIt, Char>& ctx)
+      -> OutputIt {
     basic_memory_buffer<Char> buffer;
     format_value(buffer, value, ctx.locale());
     basic_string_view<Char> str(buffer.data(), buffer.size());
     return formatter<basic_string_view<Char>, Char>::format(str, ctx);
   }
+  template <typename OutputIt>
+  auto format(const T& value, basic_printf_context<OutputIt, Char>& ctx)
+      -> OutputIt {
+    basic_memory_buffer<Char> buffer;
+    format_value(buffer, value, ctx.locale());
+    return std::copy(buffer.begin(), buffer.end(), ctx.out());
+  }
 };
-}  // namespace internal
+}  // namespace detail
 
 template <typename Char>
 void vprint(std::basic_ostream<Char>& os, basic_string_view<Char> format_str,
-            basic_format_args<buffer_context<Char>> args) {
+            basic_format_args<buffer_context<type_identity_t<Char>>> args) {
   basic_memory_buffer<Char> buffer;
-  internal::vformat_to(buffer, format_str, args);
-  internal::write(os, buffer);
+  detail::vformat_to(buffer, format_str, args);
+  detail::write_buffer(os, buffer);
 }
 
 /**
@@ -131,10 +167,10 @@ void vprint(std::basic_ostream<Char>& os, basic_string_view<Char> format_str,
   \endrst
  */
 template <typename S, typename... Args,
-          typename Char = enable_if_t<internal::is_string<S>::value, char_t<S>>>
+          typename Char = enable_if_t<detail::is_string<S>::value, char_t<S>>>
 void print(std::basic_ostream<Char>& os, const S& format_str, Args&&... args) {
   vprint(os, to_string_view(format_str),
-         {internal::make_args_checked<Args...>(format_str, args...)});
+         fmt::make_args_checked<Args...>(format_str, args...));
 }
 FMT_END_NAMESPACE
 
diff --git a/Externals/fmt/include/fmt/posix.h b/Externals/fmt/include/fmt/posix.h
index e68e226f3f1c..da19e9d530c9 100755
--- a/Externals/fmt/include/fmt/posix.h
+++ b/Externals/fmt/include/fmt/posix.h
@@ -1,321 +1,2 @@
-// A C++ interface to POSIX functions.
-//
-// Copyright (c) 2012 - 2016, Victor Zverovich
-// All rights reserved.
-//
-// For the license information refer to format.h.
-
-#ifndef FMT_POSIX_H_
-#define FMT_POSIX_H_
-
-#if defined(__MINGW32__) || defined(__CYGWIN__)
-// Workaround MinGW bug https://sourceforge.net/p/mingw/bugs/2024/.
-#  undef __STRICT_ANSI__
-#endif
-
-#include <cerrno>
-#include <clocale>  // for locale_t
-#include <cstdio>
-#include <cstdlib>  // for strtod_l
-
-#include <cstddef>
-
-#if defined __APPLE__ || defined(__FreeBSD__)
-#  include <xlocale.h>  // for LC_NUMERIC_MASK on OS X
-#endif
-
-#include "format.h"
-
-// UWP doesn't provide _pipe.
-#if FMT_HAS_INCLUDE("winapifamily.h")
-#  include <winapifamily.h>
-#endif
-#if FMT_HAS_INCLUDE("fcntl.h") && \
-    (!defined(WINAPI_FAMILY) || (WINAPI_FAMILY == WINAPI_FAMILY_DESKTOP_APP))
-#  include <fcntl.h>  // for O_RDONLY
-#  define FMT_USE_FCNTL 1
-#else
-#  define FMT_USE_FCNTL 0
-#endif
-
-#ifndef FMT_POSIX
-#  if defined(_WIN32) && !defined(__MINGW32__)
-// Fix warnings about deprecated symbols.
-#    define FMT_POSIX(call) _##call
-#  else
-#    define FMT_POSIX(call) call
-#  endif
-#endif
-
-// Calls to system functions are wrapped in FMT_SYSTEM for testability.
-#ifdef FMT_SYSTEM
-#  define FMT_POSIX_CALL(call) FMT_SYSTEM(call)
-#else
-#  define FMT_SYSTEM(call) call
-#  ifdef _WIN32
-// Fix warnings about deprecated symbols.
-#    define FMT_POSIX_CALL(call) ::_##call
-#  else
-#    define FMT_POSIX_CALL(call) ::call
-#  endif
-#endif
-
-// Retries the expression while it evaluates to error_result and errno
-// equals to EINTR.
-#ifndef _WIN32
-#  define FMT_RETRY_VAL(result, expression, error_result) \
-    do {                                                  \
-      (result) = (expression);                            \
-    } while ((result) == (error_result) && errno == EINTR)
-#else
-#  define FMT_RETRY_VAL(result, expression, error_result) result = (expression)
-#endif
-
-#define FMT_RETRY(result, expression) FMT_RETRY_VAL(result, expression, -1)
-
-FMT_BEGIN_NAMESPACE
-
-/**
-  \rst
-  A reference to a null-terminated string. It can be constructed from a C
-  string or ``std::string``.
-
-  You can use one of the following type aliases for common character types:
-
-  +---------------+-----------------------------+
-  | Type          | Definition                  |
-  +===============+=============================+
-  | cstring_view  | basic_cstring_view<char>    |
-  +---------------+-----------------------------+
-  | wcstring_view | basic_cstring_view<wchar_t> |
-  +---------------+-----------------------------+
-
-  This class is most useful as a parameter type to allow passing
-  different types of strings to a function, for example::
-
-    template <typename... Args>
-    std::string format(cstring_view format_str, const Args & ... args);
-
-    format("{}", 42);
-    format(std::string("{}"), 42);
-  \endrst
- */
-template <typename Char> class basic_cstring_view {
- private:
-  const Char* data_;
-
- public:
-  /** Constructs a string reference object from a C string. */
-  basic_cstring_view(const Char* s) : data_(s) {}
-
-  /**
-    \rst
-    Constructs a string reference from an ``std::string`` object.
-    \endrst
-   */
-  basic_cstring_view(const std::basic_string<Char>& s) : data_(s.c_str()) {}
-
-  /** Returns the pointer to a C string. */
-  const Char* c_str() const { return data_; }
-};
-
-using cstring_view = basic_cstring_view<char>;
-using wcstring_view = basic_cstring_view<wchar_t>;
-
-// An error code.
-class error_code {
- private:
-  int value_;
-
- public:
-  explicit error_code(int value = 0) FMT_NOEXCEPT : value_(value) {}
-
-  int get() const FMT_NOEXCEPT { return value_; }
-};
-
-// A buffered file.
-class buffered_file {
- private:
-  FILE* file_;
-
-  friend class file;
-
-  explicit buffered_file(FILE* f) : file_(f) {}
-
- public:
-  buffered_file(const buffered_file&) = delete;
-  void operator=(const buffered_file&) = delete;
-
-  // Constructs a buffered_file object which doesn't represent any file.
-  buffered_file() FMT_NOEXCEPT : file_(nullptr) {}
-
-  // Destroys the object closing the file it represents if any.
-  FMT_API ~buffered_file() FMT_NOEXCEPT;
-
- public:
-  buffered_file(buffered_file&& other) FMT_NOEXCEPT : file_(other.file_) {
-    other.file_ = nullptr;
-  }
-
-  buffered_file& operator=(buffered_file&& other) {
-    close();
-    file_ = other.file_;
-    other.file_ = nullptr;
-    return *this;
-  }
-
-  // Opens a file.
-  FMT_API buffered_file(cstring_view filename, cstring_view mode);
-
-  // Closes the file.
-  FMT_API void close();
-
-  // Returns the pointer to a FILE object representing this file.
-  FILE* get() const FMT_NOEXCEPT { return file_; }
-
-  // We place parentheses around fileno to workaround a bug in some versions
-  // of MinGW that define fileno as a macro.
-  FMT_API int(fileno)() const;
-
-  void vprint(string_view format_str, format_args args) {
-    fmt::vprint(file_, format_str, args);
-  }
-
-  template <typename... Args>
-  inline void print(string_view format_str, const Args&... args) {
-    vprint(format_str, make_format_args(args...));
-  }
-};
-
-#if FMT_USE_FCNTL
-// A file. Closed file is represented by a file object with descriptor -1.
-// Methods that are not declared with FMT_NOEXCEPT may throw
-// fmt::system_error in case of failure. Note that some errors such as
-// closing the file multiple times will cause a crash on Windows rather
-// than an exception. You can get standard behavior by overriding the
-// invalid parameter handler with _set_invalid_parameter_handler.
-class file {
- private:
-  int fd_;  // File descriptor.
-
-  // Constructs a file object with a given descriptor.
-  explicit file(int fd) : fd_(fd) {}
-
- public:
-  // Possible values for the oflag argument to the constructor.
-  enum {
-    RDONLY = FMT_POSIX(O_RDONLY),  // Open for reading only.
-    WRONLY = FMT_POSIX(O_WRONLY),  // Open for writing only.
-    RDWR = FMT_POSIX(O_RDWR)       // Open for reading and writing.
-  };
-
-  // Constructs a file object which doesn't represent any file.
-  file() FMT_NOEXCEPT : fd_(-1) {}
-
-  // Opens a file and constructs a file object representing this file.
-  FMT_API file(cstring_view path, int oflag);
-
- public:
-  file(const file&) = delete;
-  void operator=(const file&) = delete;
-
-  file(file&& other) FMT_NOEXCEPT : fd_(other.fd_) { other.fd_ = -1; }
-
-  file& operator=(file&& other) FMT_NOEXCEPT {
-    close();
-    fd_ = other.fd_;
-    other.fd_ = -1;
-    return *this;
-  }
-
-  // Destroys the object closing the file it represents if any.
-  FMT_API ~file() FMT_NOEXCEPT;
-
-  // Returns the file descriptor.
-  int descriptor() const FMT_NOEXCEPT { return fd_; }
-
-  // Closes the file.
-  FMT_API void close();
-
-  // Returns the file size. The size has signed type for consistency with
-  // stat::st_size.
-  FMT_API long long size() const;
-
-  // Attempts to read count bytes from the file into the specified buffer.
-  FMT_API std::size_t read(void* buffer, std::size_t count);
-
-  // Attempts to write count bytes from the specified buffer to the file.
-  FMT_API std::size_t write(const void* buffer, std::size_t count);
-
-  // Duplicates a file descriptor with the dup function and returns
-  // the duplicate as a file object.
-  FMT_API static file dup(int fd);
-
-  // Makes fd be the copy of this file descriptor, closing fd first if
-  // necessary.
-  FMT_API void dup2(int fd);
-
-  // Makes fd be the copy of this file descriptor, closing fd first if
-  // necessary.
-  FMT_API void dup2(int fd, error_code& ec) FMT_NOEXCEPT;
-
-  // Creates a pipe setting up read_end and write_end file objects for reading
-  // and writing respectively.
-  FMT_API static void pipe(file& read_end, file& write_end);
-
-  // Creates a buffered_file object associated with this file and detaches
-  // this file object from the file.
-  FMT_API buffered_file fdopen(const char* mode);
-};
-
-// Returns the memory page size.
-long getpagesize();
-#endif  // FMT_USE_FCNTL
-
-#ifdef FMT_LOCALE
-// A "C" numeric locale.
-class Locale {
- private:
-#  ifdef _WIN32
-  using locale_t = _locale_t;
-
-  enum { LC_NUMERIC_MASK = LC_NUMERIC };
-
-  static locale_t newlocale(int category_mask, const char* locale, locale_t) {
-    return _create_locale(category_mask, locale);
-  }
-
-  static void freelocale(locale_t locale) { _free_locale(locale); }
-
-  static double strtod_l(const char* nptr, char** endptr, _locale_t locale) {
-    return _strtod_l(nptr, endptr, locale);
-  }
-#  endif
-
-  locale_t locale_;
-
- public:
-  using type = locale_t;
-  Locale(const Locale&) = delete;
-  void operator=(const Locale&) = delete;
-
-  Locale() : locale_(newlocale(LC_NUMERIC_MASK, "C", nullptr)) {
-    if (!locale_) FMT_THROW(system_error(errno, "cannot create locale"));
-  }
-  ~Locale() { freelocale(locale_); }
-
-  type get() const { return locale_; }
-
-  // Converts string to floating-point number and advances str past the end
-  // of the parsed input.
-  double strtod(const char*& str) const {
-    char* end = nullptr;
-    double result = strtod_l(str, &end, locale_);
-    str = end;
-    return result;
-  }
-};
-#endif  // FMT_LOCALE
-FMT_END_NAMESPACE
-
-#endif  // FMT_POSIX_H_
+#include "os.h"
+#warning "fmt/posix.h is deprecated; use fmt/os.h instead"
diff --git a/Externals/fmt/include/fmt/printf.h b/Externals/fmt/include/fmt/printf.h
index a2fa945d4b85..8c28ac232727 100755
--- a/Externals/fmt/include/fmt/printf.h
+++ b/Externals/fmt/include/fmt/printf.h
@@ -14,7 +14,7 @@
 #include "ostream.h"
 
 FMT_BEGIN_NAMESPACE
-namespace internal {
+namespace detail {
 
 // Checks if a value fits in int - used to avoid warnings about comparing
 // signed and unsigned integers.
@@ -28,7 +28,7 @@ template <bool IsSigned> struct int_checker {
 
 template <> struct int_checker<true> {
   template <typename T> static bool fits_in_int(T value) {
-    return value >= std::numeric_limits<int>::min() &&
+    return value >= (std::numeric_limits<int>::min)() &&
            value <= max_value<int>();
   }
   static bool fits_in_int(int) { return true; }
@@ -90,11 +90,11 @@ template <typename T, typename Context> class arg_converter {
     if (const_check(sizeof(target_type) <= sizeof(int))) {
       // Extra casts are used to silence warnings.
       if (is_signed) {
-        arg_ = internal::make_arg<Context>(
+        arg_ = detail::make_arg<Context>(
             static_cast<int>(static_cast<target_type>(value)));
       } else {
         using unsigned_type = typename make_unsigned_or_bool<target_type>::type;
-        arg_ = internal::make_arg<Context>(
+        arg_ = detail::make_arg<Context>(
             static_cast<unsigned>(static_cast<unsigned_type>(value)));
       }
     } else {
@@ -102,9 +102,9 @@ template <typename T, typename Context> class arg_converter {
         // glibc's printf doesn't sign extend arguments of smaller types:
         //   std::printf("%lld", -42);  // prints "4294967254"
         // but we don't have to do the same because it's a UB.
-        arg_ = internal::make_arg<Context>(static_cast<long long>(value));
+        arg_ = detail::make_arg<Context>(static_cast<long long>(value));
       } else {
-        arg_ = internal::make_arg<Context>(
+        arg_ = detail::make_arg<Context>(
             static_cast<typename make_unsigned_or_bool<U>::type>(value));
       }
     }
@@ -133,7 +133,7 @@ template <typename Context> class char_converter {
 
   template <typename T, FMT_ENABLE_IF(std::is_integral<T>::value)>
   void operator()(T value) {
-    arg_ = internal::make_arg<Context>(
+    arg_ = detail::make_arg<Context>(
         static_cast<typename Context::char_type>(value));
   }
 
@@ -141,6 +141,13 @@ template <typename Context> class char_converter {
   void operator()(T) {}  // No conversion needed for non-integral types.
 };
 
+// An argument visitor that return a pointer to a C string if argument is a
+// string or null otherwise.
+template <typename Char> struct get_cstring {
+  template <typename T> const Char* operator()(T) { return nullptr; }
+  const Char* operator()(const Char* s) { return s; }
+};
+
 // Checks if an argument is a valid printf width specifier and sets
 // left alignment if it is negative.
 template <typename Char> class printf_width_handler {
@@ -155,7 +162,7 @@ template <typename Char> class printf_width_handler {
   template <typename T, FMT_ENABLE_IF(std::is_integral<T>::value)>
   unsigned operator()(T value) {
     auto width = static_cast<uint32_or_64_or_128_t<T>>(value);
-    if (internal::is_negative(value)) {
+    if (detail::is_negative(value)) {
       specs_.align = align::left;
       width = 0 - width;
     }
@@ -172,23 +179,25 @@ template <typename Char> class printf_width_handler {
 };
 
 template <typename Char, typename Context>
-void printf(buffer<Char>& buf, basic_string_view<Char> format,
-            basic_format_args<Context> args) {
-  Context(std::back_inserter(buf), format, args).format();
+void vprintf(buffer<Char>& buf, basic_string_view<Char> format,
+             basic_format_args<Context> args) {
+  Context(buffer_appender<Char>(buf), format, args).format();
 }
+}  // namespace detail
 
-template <typename OutputIt, typename Char, typename Context>
-internal::truncating_iterator<OutputIt> printf(
-    internal::truncating_iterator<OutputIt> it, basic_string_view<Char> format,
-    basic_format_args<Context> args) {
-  return Context(it, format, args).format();
+// For printing into memory_buffer.
+template <typename Char, typename Context>
+FMT_DEPRECATED void printf(detail::buffer<Char>& buf,
+                           basic_string_view<Char> format,
+                           basic_format_args<Context> args) {
+  return detail::vprintf(buf, format, args);
 }
-}  // namespace internal
-
-using internal::printf;  // For printing into memory_buffer.
-
-template <typename Range> class printf_arg_formatter;
+using detail::vprintf;
 
+template <typename Char>
+class basic_printf_parse_context : public basic_format_parse_context<Char> {
+  using basic_format_parse_context<Char>::basic_format_parse_context;
+};
 template <typename OutputIt, typename Char> class basic_printf_context;
 
 /**
@@ -196,15 +205,15 @@ template <typename OutputIt, typename Char> class basic_printf_context;
   The ``printf`` argument formatter.
   \endrst
  */
-template <typename Range>
-class printf_arg_formatter : public internal::arg_formatter_base<Range> {
+template <typename OutputIt, typename Char>
+class printf_arg_formatter : public detail::arg_formatter_base<OutputIt, Char> {
  public:
-  using iterator = typename Range::iterator;
+  using iterator = OutputIt;
 
  private:
-  using char_type = typename Range::value_type;
-  using base = internal::arg_formatter_base<Range>;
-  using context_type = basic_printf_context<iterator, char_type>;
+  using char_type = Char;
+  using base = detail::arg_formatter_base<OutputIt, Char>;
+  using context_type = basic_printf_context<OutputIt, Char>;
 
   context_type& context_;
 
@@ -229,9 +238,9 @@ class printf_arg_formatter : public internal::arg_formatter_base<Range> {
     \endrst
    */
   printf_arg_formatter(iterator iter, format_specs& specs, context_type& ctx)
-      : base(Range(iter), &specs, internal::locale_ref()), context_(ctx) {}
+      : base(iter, &specs, detail::locale_ref()), context_(ctx) {}
 
-  template <typename T, FMT_ENABLE_IF(fmt::internal::is_integral<T>::value)>
+  template <typename T, FMT_ENABLE_IF(fmt::detail::is_integral<T>::value)>
   iterator operator()(T value) {
     // MSVC2013 fails to compile separate overloads for bool and char_type so
     // use std::is_same instead.
@@ -246,7 +255,11 @@ class printf_arg_formatter : public internal::arg_formatter_base<Range> {
         return (*this)(static_cast<int>(value));
       fmt_specs.sign = sign::none;
       fmt_specs.alt = false;
-      fmt_specs.align = align::right;
+      fmt_specs.fill[0] = ' ';  // Ignore '0' flag for char types.
+      // align::numeric needs to be overwritten here since the '0' flag is
+      // ignored for non-numeric types
+      if (fmt_specs.align == align::none || fmt_specs.align == align::numeric)
+        fmt_specs.align = align::right;
       return base::operator()(value);
     } else {
       return base::operator()(value);
@@ -303,6 +316,8 @@ class printf_arg_formatter : public internal::arg_formatter_base<Range> {
 };
 
 template <typename T> struct printf_formatter {
+  printf_formatter() = delete;
+
   template <typename ParseContext>
   auto parse(ParseContext& ctx) -> decltype(ctx.begin()) {
     return ctx.begin();
@@ -310,17 +325,21 @@ template <typename T> struct printf_formatter {
 
   template <typename FormatContext>
   auto format(const T& value, FormatContext& ctx) -> decltype(ctx.out()) {
-    internal::format_value(internal::get_container(ctx.out()), value);
+    detail::format_value(detail::get_container(ctx.out()), value);
     return ctx.out();
   }
 };
 
-/** This template formats data and writes the output to a writer. */
+/**
+ This template formats data and writes the output through an output iterator.
+ */
 template <typename OutputIt, typename Char> class basic_printf_context {
  public:
   /** The character type for the output. */
   using char_type = Char;
+  using iterator = OutputIt;
   using format_arg = basic_format_arg<basic_printf_context>;
+  using parse_context_type = basic_printf_parse_context<Char>;
   template <typename T> using formatter_type = printf_formatter<T>;
 
  private:
@@ -328,7 +347,7 @@ template <typename OutputIt, typename Char> class basic_printf_context {
 
   OutputIt out_;
   basic_format_args<basic_printf_context> args_;
-  basic_format_parse_context<Char> parse_ctx_;
+  parse_context_type parse_ctx_;
 
   static void parse_flags(format_specs& specs, const Char*& it,
                           const Char* end);
@@ -343,9 +362,8 @@ template <typename OutputIt, typename Char> class basic_printf_context {
  public:
   /**
    \rst
-   Constructs a ``printf_context`` object. References to the arguments and
-   the writer are stored in the context object so make sure they have
-   appropriate lifetimes.
+   Constructs a ``printf_context`` object. References to the arguments are
+   stored in the context object so make sure they have appropriate lifetimes.
    \endrst
    */
   basic_printf_context(OutputIt out, basic_string_view<char_type> format_str,
@@ -355,16 +373,18 @@ template <typename OutputIt, typename Char> class basic_printf_context {
   OutputIt out() { return out_; }
   void advance_to(OutputIt it) { out_ = it; }
 
+  detail::locale_ref locale() { return {}; }
+
   format_arg arg(int id) const { return args_.get(id); }
 
-  basic_format_parse_context<Char>& parse_context() { return parse_ctx_; }
+  parse_context_type& parse_context() { return parse_ctx_; }
 
   FMT_CONSTEXPR void on_error(const char* message) {
     parse_ctx_.on_error(message);
   }
 
   /** Formats stored arguments and writes the output to the range. */
-  template <typename ArgFormatter = printf_arg_formatter<buffer_range<Char>>>
+  template <typename ArgFormatter = printf_arg_formatter<OutputIt, Char>>
   OutputIt format();
 };
 
@@ -384,7 +404,9 @@ void basic_printf_context<OutputIt, Char>::parse_flags(format_specs& specs,
       specs.fill[0] = '0';
       break;
     case ' ':
-      specs.sign = sign::space;
+      if (specs.sign != sign::plus) {
+        specs.sign = sign::space;
+      }
       break;
     case '#':
       specs.alt = true;
@@ -402,18 +424,19 @@ basic_printf_context<OutputIt, Char>::get_arg(int arg_index) {
     arg_index = parse_ctx_.next_arg_id();
   else
     parse_ctx_.check_arg_id(--arg_index);
-  return internal::get_arg(*this, arg_index);
+  return detail::get_arg(*this, arg_index);
 }
 
 template <typename OutputIt, typename Char>
-int basic_printf_context<OutputIt, Char>::parse_header(
-    const Char*& it, const Char* end, format_specs& specs) {
+int basic_printf_context<OutputIt, Char>::parse_header(const Char*& it,
+                                                       const Char* end,
+                                                       format_specs& specs) {
   int arg_index = -1;
   char_type c = *it;
   if (c >= '0' && c <= '9') {
     // Parse an argument index (if followed by '$') or a width possibly
     // preceded with '0' flag(s).
-    internal::error_handler eh;
+    detail::error_handler eh;
     int value = parse_nonnegative_int(it, end, eh);
     if (it != end && *it == '$') {  // value is an argument index
       ++it;
@@ -432,12 +455,12 @@ int basic_printf_context<OutputIt, Char>::parse_header(
   // Parse width.
   if (it != end) {
     if (*it >= '0' && *it <= '9') {
-      internal::error_handler eh;
+      detail::error_handler eh;
       specs.width = parse_nonnegative_int(it, end, eh);
     } else if (*it == '*') {
       ++it;
       specs.width = static_cast<int>(visit_format_arg(
-          internal::printf_width_handler<char_type>(specs), get_arg()));
+          detail::printf_width_handler<char_type>(specs), get_arg()));
     }
   }
   return arg_index;
@@ -465,38 +488,52 @@ OutputIt basic_printf_context<OutputIt, Char>::format() {
 
     // Parse argument index, flags and width.
     int arg_index = parse_header(it, end, specs);
-    if (arg_index == 0) on_error("argument index out of range");
+    if (arg_index == 0) on_error("argument not found");
 
     // Parse precision.
     if (it != end && *it == '.') {
       ++it;
       c = it != end ? *it : 0;
       if ('0' <= c && c <= '9') {
-        internal::error_handler eh;
+        detail::error_handler eh;
         specs.precision = parse_nonnegative_int(it, end, eh);
       } else if (c == '*') {
         ++it;
-        specs.precision =
-            static_cast<int>(visit_format_arg(internal::printf_precision_handler(), get_arg()));
+        specs.precision = static_cast<int>(
+            visit_format_arg(detail::printf_precision_handler(), get_arg()));
       } else {
         specs.precision = 0;
       }
     }
 
     format_arg arg = get_arg(arg_index);
-    if (specs.alt && visit_format_arg(internal::is_zero_int(), arg))
+    // For d, i, o, u, x, and X conversion specifiers, if a precision is
+    // specified, the '0' flag is ignored
+    if (specs.precision >= 0 && arg.is_integral())
+      specs.fill[0] =
+          ' ';  // Ignore '0' flag for non-numeric types or if '-' present.
+    if (specs.precision >= 0 && arg.type() == detail::type::cstring_type) {
+      auto str = visit_format_arg(detail::get_cstring<Char>(), arg);
+      auto str_end = str + specs.precision;
+      auto nul = std::find(str, str_end, Char());
+      arg = detail::make_arg<basic_printf_context>(basic_string_view<Char>(
+          str,
+          detail::to_unsigned(nul != str_end ? nul - str : specs.precision)));
+    }
+    if (specs.alt && visit_format_arg(detail::is_zero_int(), arg))
       specs.alt = false;
     if (specs.fill[0] == '0') {
-      if (arg.is_arithmetic())
+      if (arg.is_arithmetic() && specs.align != align::left)
         specs.align = align::numeric;
       else
-        specs.fill[0] = ' ';  // Ignore '0' flag for non-numeric types.
+        specs.fill[0] = ' ';  // Ignore '0' flag for non-numeric types or if '-'
+                              // flag is also present.
     }
 
     // Parse length and convert the argument to the required type.
     c = it != end ? *it++ : 0;
     char_type t = it != end ? *it : 0;
-    using internal::convert_arg;
+    using detail::convert_arg;
     switch (c) {
     case 'h':
       if (t == 'h') {
@@ -520,7 +557,7 @@ OutputIt basic_printf_context<OutputIt, Char>::format() {
       convert_arg<intmax_t>(arg, t);
       break;
     case 'z':
-      convert_arg<std::size_t>(arg, t);
+      convert_arg<size_t>(arg, t);
       break;
     case 't':
       convert_arg<std::ptrdiff_t>(arg, t);
@@ -545,7 +582,7 @@ OutputIt basic_printf_context<OutputIt, Char>::format() {
         specs.type = 'd';
         break;
       case 'c':
-        visit_format_arg(internal::char_converter<basic_printf_context>(arg),
+        visit_format_arg(detail::char_converter<basic_printf_context>(arg),
                          arg);
         break;
       }
@@ -554,15 +591,14 @@ OutputIt basic_printf_context<OutputIt, Char>::format() {
     start = it;
 
     // Format argument.
-    visit_format_arg(ArgFormatter(out, specs, *this), arg);
+    out = visit_format_arg(ArgFormatter(out, specs, *this), arg);
   }
   return std::copy(start, it, out);
 }
 
 template <typename Char>
 using basic_printf_context_t =
-    basic_printf_context<std::back_insert_iterator<internal::buffer<Char>>,
-                         Char>;
+    basic_printf_context<detail::buffer_appender<Char>, Char>;
 
 using printf_context = basic_printf_context_t<char>;
 using wprintf_context = basic_printf_context_t<wchar_t>;
@@ -596,9 +632,10 @@ inline format_arg_store<wprintf_context, Args...> make_wprintf_args(
 
 template <typename S, typename Char = char_t<S>>
 inline std::basic_string<Char> vsprintf(
-    const S& format, basic_format_args<basic_printf_context_t<Char>> args) {
+    const S& format,
+    basic_format_args<basic_printf_context_t<type_identity_t<Char>>> args) {
   basic_memory_buffer<Char> buffer;
-  printf(buffer, to_string_view(format), args);
+  vprintf(buffer, to_string_view(format), args);
   return to_string(buffer);
 }
 
@@ -612,18 +649,19 @@ inline std::basic_string<Char> vsprintf(
   \endrst
 */
 template <typename S, typename... Args,
-          typename Char = enable_if_t<internal::is_string<S>::value, char_t<S>>>
+          typename Char = enable_if_t<detail::is_string<S>::value, char_t<S>>>
 inline std::basic_string<Char> sprintf(const S& format, const Args&... args) {
   using context = basic_printf_context_t<Char>;
-  return vsprintf(to_string_view(format), {make_format_args<context>(args...)});
+  return vsprintf(to_string_view(format), make_format_args<context>(args...));
 }
 
 template <typename S, typename Char = char_t<S>>
-inline int vfprintf(std::FILE* f, const S& format,
-                    basic_format_args<basic_printf_context_t<Char>> args) {
+inline int vfprintf(
+    std::FILE* f, const S& format,
+    basic_format_args<basic_printf_context_t<type_identity_t<Char>>> args) {
   basic_memory_buffer<Char> buffer;
-  printf(buffer, to_string_view(format), args);
-  std::size_t size = buffer.size();
+  vprintf(buffer, to_string_view(format), args);
+  size_t size = buffer.size();
   return std::fwrite(buffer.data(), sizeof(Char), size, f) < size
              ? -1
              : static_cast<int>(size);
@@ -639,16 +677,17 @@ inline int vfprintf(std::FILE* f, const S& format,
   \endrst
  */
 template <typename S, typename... Args,
-          typename Char = enable_if_t<internal::is_string<S>::value, char_t<S>>>
+          typename Char = enable_if_t<detail::is_string<S>::value, char_t<S>>>
 inline int fprintf(std::FILE* f, const S& format, const Args&... args) {
   using context = basic_printf_context_t<Char>;
   return vfprintf(f, to_string_view(format),
-                  {make_format_args<context>(args...)});
+                  make_format_args<context>(args...));
 }
 
 template <typename S, typename Char = char_t<S>>
-inline int vprintf(const S& format,
-                   basic_format_args<basic_printf_context_t<Char>> args) {
+inline int vprintf(
+    const S& format,
+    basic_format_args<basic_printf_context_t<type_identity_t<Char>>> args) {
   return vfprintf(stdout, to_string_view(format), args);
 }
 
@@ -662,19 +701,20 @@ inline int vprintf(const S& format,
   \endrst
  */
 template <typename S, typename... Args,
-          FMT_ENABLE_IF(internal::is_string<S>::value)>
+          FMT_ENABLE_IF(detail::is_string<S>::value)>
 inline int printf(const S& format_str, const Args&... args) {
   using context = basic_printf_context_t<char_t<S>>;
   return vprintf(to_string_view(format_str),
-                 {make_format_args<context>(args...)});
+                 make_format_args<context>(args...));
 }
 
 template <typename S, typename Char = char_t<S>>
-inline int vfprintf(std::basic_ostream<Char>& os, const S& format,
-                    basic_format_args<basic_printf_context_t<Char>> args) {
+inline int vfprintf(
+    std::basic_ostream<Char>& os, const S& format,
+    basic_format_args<basic_printf_context_t<type_identity_t<Char>>> args) {
   basic_memory_buffer<Char> buffer;
-  printf(buffer, to_string_view(format), args);
-  internal::write(os, buffer);
+  vprintf(buffer, to_string_view(format), args);
+  detail::write_buffer(os, buffer);
   return static_cast<int>(buffer.size());
 }
 
@@ -682,9 +722,9 @@ inline int vfprintf(std::basic_ostream<Char>& os, const S& format,
 template <typename ArgFormatter, typename Char,
           typename Context =
               basic_printf_context<typename ArgFormatter::iterator, Char>>
-typename ArgFormatter::iterator vprintf(internal::buffer<Char>& out,
-                                        basic_string_view<Char> format_str,
-                                        basic_format_args<Context> args) {
+typename ArgFormatter::iterator vprintf(
+    detail::buffer<Char>& out, basic_string_view<Char> format_str,
+    basic_format_args<type_identity_t<Context>> args) {
   typename ArgFormatter::iterator iter(out);
   Context(iter, format_str, args).template format<ArgFormatter>();
   return iter;
@@ -704,7 +744,7 @@ inline int fprintf(std::basic_ostream<Char>& os, const S& format_str,
                    const Args&... args) {
   using context = basic_printf_context_t<Char>;
   return vfprintf(os, to_string_view(format_str),
-                  {make_format_args<context>(args...)});
+                  make_format_args<context>(args...));
 }
 FMT_END_NAMESPACE
 
diff --git a/Externals/fmt/include/fmt/ranges.h b/Externals/fmt/include/fmt/ranges.h
index 6110fdaf1943..b603d637d74b 100755
--- a/Externals/fmt/include/fmt/ranges.h
+++ b/Externals/fmt/include/fmt/ranges.h
@@ -12,7 +12,9 @@
 #ifndef FMT_RANGES_H_
 #define FMT_RANGES_H_
 
+#include <initializer_list>
 #include <type_traits>
+
 #include "format.h"
 
 // output only up to N items from the range.
@@ -31,7 +33,7 @@ template <typename Char> struct formatting_base {
 
 template <typename Char, typename Enable = void>
 struct formatting_range : formatting_base<Char> {
-  static FMT_CONSTEXPR_DECL const std::size_t range_length_limit =
+  static FMT_CONSTEXPR_DECL const size_t range_length_limit =
       FMT_RANGE_OUTPUT_LENGTH_LIMIT;  // output only up to N items from the
                                       // range.
   Char prefix;
@@ -52,7 +54,7 @@ struct formatting_tuple : formatting_base<Char> {
   static FMT_CONSTEXPR_DECL const bool add_prepostfix_space = false;
 };
 
-namespace internal {
+namespace detail {
 
 template <typename RangeT, typename OutputIterator>
 OutputIterator copy(const RangeT& range, OutputIterator out) {
@@ -104,10 +106,7 @@ struct is_range_<
 /// tuple_size and tuple_element check.
 template <typename T> class is_tuple_like_ {
   template <typename U>
-  static auto check(U* p)
-      -> decltype(std::tuple_size<U>::value,
-                  (void)std::declval<typename std::tuple_element<0, U>::type>(),
-                  int());
+  static auto check(U* p) -> decltype(std::tuple_size<U>::value, int());
   template <typename> static void check(...);
 
  public:
@@ -119,26 +118,24 @@ template <typename T> class is_tuple_like_ {
 #if defined(__cpp_lib_integer_sequence) || FMT_MSC_VER >= 1900
 template <typename T, T... N>
 using integer_sequence = std::integer_sequence<T, N...>;
-template <std::size_t... N> using index_sequence = std::index_sequence<N...>;
-template <std::size_t N>
-using make_index_sequence = std::make_index_sequence<N>;
+template <size_t... N> using index_sequence = std::index_sequence<N...>;
+template <size_t N> using make_index_sequence = std::make_index_sequence<N>;
 #else
 template <typename T, T... N> struct integer_sequence {
   using value_type = T;
 
-  static FMT_CONSTEXPR std::size_t size() { return sizeof...(N); }
+  static FMT_CONSTEXPR size_t size() { return sizeof...(N); }
 };
 
-template <std::size_t... N>
-using index_sequence = integer_sequence<std::size_t, N...>;
+template <size_t... N> using index_sequence = integer_sequence<size_t, N...>;
 
-template <typename T, std::size_t N, T... Ns>
+template <typename T, size_t N, T... Ns>
 struct make_integer_sequence : make_integer_sequence<T, N - 1, N - 1, Ns...> {};
 template <typename T, T... Ns>
 struct make_integer_sequence<T, 0, Ns...> : integer_sequence<T, Ns...> {};
 
-template <std::size_t N>
-using make_index_sequence = make_integer_sequence<std::size_t, N>;
+template <size_t N>
+using make_index_sequence = make_integer_sequence<size_t, N>;
 #endif
 
 template <class Tuple, class F, size_t... Is>
@@ -160,6 +157,9 @@ template <class Tuple, class F> void for_each(Tuple&& tup, F&& f) {
   for_each(indexes, std::forward<Tuple>(tup), std::forward<F>(f));
 }
 
+template <typename Range>
+using value_type = remove_cvref_t<decltype(*std::declval<Range>().begin())>;
+
 template <typename Arg, FMT_ENABLE_IF(!is_like_std_string<
                                       typename std::decay<Arg>::type>::value)>
 FMT_CONSTEXPR const char* format_str_quoted(bool add_space, const Arg&) {
@@ -185,12 +185,11 @@ FMT_CONSTEXPR const char* format_str_quoted(bool add_space, const char) {
 FMT_CONSTEXPR const wchar_t* format_str_quoted(bool add_space, const wchar_t) {
   return add_space ? L" '{}'" : L"'{}'";
 }
-
-}  // namespace internal
+}  // namespace detail
 
 template <typename T> struct is_tuple_like {
   static FMT_CONSTEXPR_DECL const bool value =
-      internal::is_tuple_like_<T>::value && !internal::is_range_<T>::value;
+      detail::is_tuple_like_<T>::value && !detail::is_range_<T>::value;
 };
 
 template <typename TupleT, typename Char>
@@ -203,17 +202,17 @@ struct formatter<TupleT, Char, enable_if_t<fmt::is_tuple_like<TupleT>::value>> {
         if (formatting.add_prepostfix_space) {
           *out++ = ' ';
         }
-        out = internal::copy(formatting.delimiter, out);
+        out = detail::copy(formatting.delimiter, out);
       }
       out = format_to(out,
-                      internal::format_str_quoted(
+                      detail::format_str_quoted(
                           (formatting.add_delimiter_spaces && i > 0), v),
                       v);
       ++i;
     }
 
     formatting_tuple<Char>& formatting;
-    std::size_t& i;
+    size_t& i;
     typename std::add_lvalue_reference<decltype(
         std::declval<FormatContext>().out())>::type out;
   };
@@ -229,14 +228,14 @@ struct formatter<TupleT, Char, enable_if_t<fmt::is_tuple_like<TupleT>::value>> {
   template <typename FormatContext = format_context>
   auto format(const TupleT& values, FormatContext& ctx) -> decltype(ctx.out()) {
     auto out = ctx.out();
-    std::size_t i = 0;
-    internal::copy(formatting.prefix, out);
+    size_t i = 0;
+    detail::copy(formatting.prefix, out);
 
-    internal::for_each(values, format_each<FormatContext>{formatting, i, out});
+    detail::for_each(values, format_each<FormatContext>{formatting, i, out});
     if (formatting.add_prepostfix_space) {
       *out++ = ' ';
     }
-    internal::copy(formatting.postfix, out);
+    detail::copy(formatting.postfix, out);
 
     return ctx.out();
   }
@@ -244,15 +243,20 @@ struct formatter<TupleT, Char, enable_if_t<fmt::is_tuple_like<TupleT>::value>> {
 
 template <typename T, typename Char> struct is_range {
   static FMT_CONSTEXPR_DECL const bool value =
-      internal::is_range_<T>::value &&
-      !internal::is_like_std_string<T>::value &&
+      detail::is_range_<T>::value && !detail::is_like_std_string<T>::value &&
       !std::is_convertible<T, std::basic_string<Char>>::value &&
-      !std::is_constructible<internal::std_string_view<Char>, T>::value;
+      !std::is_constructible<detail::std_string_view<Char>, T>::value;
 };
 
-template <typename RangeT, typename Char>
-struct formatter<RangeT, Char,
-                 enable_if_t<fmt::is_range<RangeT, Char>::value>> {
+template <typename T, typename Char>
+struct formatter<
+    T, Char,
+    enable_if_t<fmt::is_range<T, Char>::value
+// Workaround a bug in MSVC 2017 and earlier.
+#if !FMT_MSC_VER || FMT_MSC_VER >= 1927
+                && has_formatter<detail::value_type<T>, format_context>::value
+#endif
+                >> {
   formatting_range<Char> formatting;
 
   template <typename ParseContext>
@@ -261,17 +265,18 @@ struct formatter<RangeT, Char,
   }
 
   template <typename FormatContext>
-  typename FormatContext::iterator format(const RangeT& values,
-                                          FormatContext& ctx) {
-    auto out = internal::copy(formatting.prefix, ctx.out());
-    std::size_t i = 0;
-    for (auto it = values.begin(), end = values.end(); it != end; ++it) {
+  typename FormatContext::iterator format(const T& values, FormatContext& ctx) {
+    auto out = detail::copy(formatting.prefix, ctx.out());
+    size_t i = 0;
+    auto it = values.begin();
+    auto end = values.end();
+    for (; it != end; ++it) {
       if (i > 0) {
         if (formatting.add_prepostfix_space) *out++ = ' ';
-        out = internal::copy(formatting.delimiter, out);
+        out = detail::copy(formatting.delimiter, out);
       }
       out = format_to(out,
-                      internal::format_str_quoted(
+                      detail::format_str_quoted(
                           (formatting.add_delimiter_spaces && i > 0), *it),
                       *it);
       if (++i > formatting.range_length_limit) {
@@ -280,11 +285,11 @@ struct formatter<RangeT, Char,
       }
     }
     if (formatting.add_prepostfix_space) *out++ = ' ';
-    return internal::copy(formatting.postfix, out);
+    return detail::copy(formatting.postfix, out);
   }
 };
 
-template <typename Char, typename... T> struct tuple_arg_join : internal::view {
+template <typename Char, typename... T> struct tuple_arg_join : detail::view {
   const std::tuple<T...>& tuple;
   basic_string_view<Char> sep;
 
@@ -302,14 +307,14 @@ struct formatter<tuple_arg_join<Char, T...>, Char> {
   template <typename FormatContext>
   typename FormatContext::iterator format(
       const tuple_arg_join<Char, T...>& value, FormatContext& ctx) {
-    return format(value, ctx, internal::make_index_sequence<sizeof...(T)>{});
+    return format(value, ctx, detail::make_index_sequence<sizeof...(T)>{});
   }
 
  private:
   template <typename FormatContext, size_t... N>
   typename FormatContext::iterator format(
       const tuple_arg_join<Char, T...>& value, FormatContext& ctx,
-      internal::index_sequence<N...>) {
+      detail::index_sequence<N...>) {
     return format_args(value, ctx, std::get<N>(value.tuple)...);
   }
 
@@ -360,6 +365,29 @@ FMT_CONSTEXPR tuple_arg_join<wchar_t, T...> join(const std::tuple<T...>& tuple,
   return {tuple, sep};
 }
 
+/**
+  \rst
+  Returns an object that formats `initializer_list` with elements separated by
+  `sep`.
+
+  **Example**::
+
+    fmt::print("{}", fmt::join({1, 2, 3}, ", "));
+    // Output: "1, 2, 3"
+  \endrst
+ */
+template <typename T>
+arg_join<const T*, const T*, char> join(std::initializer_list<T> list,
+                                        string_view sep) {
+  return join(std::begin(list), std::end(list), sep);
+}
+
+template <typename T>
+arg_join<const T*, const T*, wchar_t> join(std::initializer_list<T> list,
+                                           wstring_view sep) {
+  return join(std::begin(list), std::end(list), sep);
+}
+
 FMT_END_NAMESPACE
 
 #endif  // FMT_RANGES_H_
diff --git a/Externals/fmt/src/format.cc b/Externals/fmt/src/format.cc
index 44ba77f02869..72713416647f 100755
--- a/Externals/fmt/src/format.cc
+++ b/Externals/fmt/src/format.cc
@@ -8,169 +8,62 @@
 #include "fmt/format-inl.h"
 
 FMT_BEGIN_NAMESPACE
-namespace internal {
+namespace detail {
 
 template <typename T>
 int format_float(char* buf, std::size_t size, const char* format, int precision,
                  T value) {
-#ifdef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
+#ifdef FMT_FUZZ
   if (precision > 100000)
     throw std::runtime_error(
         "fuzz mode - avoid large allocation inside snprintf");
 #endif
   // Suppress the warning about nonliteral format string.
-  auto snprintf_ptr = FMT_SNPRINTF;
+  int (*snprintf_ptr)(char*, size_t, const char*, ...) = FMT_SNPRINTF;
   return precision < 0 ? snprintf_ptr(buf, size, format, value)
                        : snprintf_ptr(buf, size, format, precision, value);
 }
-struct sprintf_specs {
-  int precision;
-  char type;
-  bool alt : 1;
+}  // namespace detail
 
-  template <typename Char>
-  constexpr sprintf_specs(basic_format_specs<Char> specs)
-      : precision(specs.precision), type(specs.type), alt(specs.alt) {}
-
-  constexpr bool has_precision() const { return precision >= 0; }
-};
-
-// This is deprecated and is kept only to preserve ABI compatibility.
-template <typename Double>
-char* sprintf_format(Double value, internal::buffer<char>& buf,
-                     sprintf_specs specs) {
-  // Buffer capacity must be non-zero, otherwise MSVC's vsnprintf_s will fail.
-  FMT_ASSERT(buf.capacity() != 0, "empty buffer");
-
-  // Build format string.
-  enum { max_format_size = 10 };  // longest format: %#-*.*Lg
-  char format[max_format_size];
-  char* format_ptr = format;
-  *format_ptr++ = '%';
-  if (specs.alt || !specs.type) *format_ptr++ = '#';
-  if (specs.precision >= 0) {
-    *format_ptr++ = '.';
-    *format_ptr++ = '*';
-  }
-  if (std::is_same<Double, long double>::value) *format_ptr++ = 'L';
-
-  char type = specs.type;
-
-  if (type == '%')
-    type = 'f';
-  else if (type == 0 || type == 'n')
-    type = 'g';
-#if FMT_MSC_VER
-  if (type == 'F') {
-    // MSVC's printf doesn't support 'F'.
-    type = 'f';
-  }
-#endif
-  *format_ptr++ = type;
-  *format_ptr = '\0';
-
-  // Format using snprintf.
-  char* start = nullptr;
-  char* decimal_point_pos = nullptr;
-  for (;;) {
-    std::size_t buffer_size = buf.capacity();
-    start = &buf[0];
-    int result =
-        format_float(start, buffer_size, format, specs.precision, value);
-    if (result >= 0) {
-      unsigned n = internal::to_unsigned(result);
-      if (n < buf.capacity()) {
-        // Find the decimal point.
-        auto p = buf.data(), end = p + n;
-        if (*p == '+' || *p == '-') ++p;
-        if (specs.type != 'a' && specs.type != 'A') {
-          while (p < end && *p >= '0' && *p <= '9') ++p;
-          if (p < end && *p != 'e' && *p != 'E') {
-            decimal_point_pos = p;
-            if (!specs.type) {
-              // Keep only one trailing zero after the decimal point.
-              ++p;
-              if (*p == '0') ++p;
-              while (p != end && *p >= '1' && *p <= '9') ++p;
-              char* where = p;
-              while (p != end && *p == '0') ++p;
-              if (p == end || *p < '0' || *p > '9') {
-                if (p != end) std::memmove(where, p, to_unsigned(end - p));
-                n -= static_cast<unsigned>(p - where);
-              }
-            }
-          }
-        }
-        buf.resize(n);
-        break;  // The buffer is large enough - continue with formatting.
-      }
-      buf.reserve(n + 1);
-    } else {
-      // If result is negative we ask to increase the capacity by at least 1,
-      // but as std::vector, the buffer grows exponentially.
-      buf.reserve(buf.capacity() + 1);
-    }
-  }
-  return decimal_point_pos;
-}
-}  // namespace internal
-
-template FMT_API char* internal::sprintf_format(double, internal::buffer<char>&,
-                                                sprintf_specs);
-template FMT_API char* internal::sprintf_format(long double,
-                                                internal::buffer<char>&,
-                                                sprintf_specs);
-
-template struct FMT_API internal::basic_data<void>;
+template struct FMT_INSTANTIATION_DEF_API detail::basic_data<void>;
 
 // Workaround a bug in MSVC2013 that prevents instantiation of format_float.
-int (*instantiate_format_float)(double, int, internal::float_specs,
-                                internal::buffer<char>&) =
-    internal::format_float;
+int (*instantiate_format_float)(double, int, detail::float_specs,
+                                detail::buffer<char>&) = detail::format_float;
 
 #ifndef FMT_STATIC_THOUSANDS_SEPARATOR
-template FMT_API internal::locale_ref::locale_ref(const std::locale& loc);
-template FMT_API std::locale internal::locale_ref::get<std::locale>() const;
+template FMT_API detail::locale_ref::locale_ref(const std::locale& loc);
+template FMT_API std::locale detail::locale_ref::get<std::locale>() const;
 #endif
 
 // Explicit instantiations for char.
 
-template FMT_API std::string internal::grouping_impl<char>(locale_ref);
-template FMT_API char internal::thousands_sep_impl(locale_ref);
-template FMT_API char internal::decimal_point_impl(locale_ref);
+template FMT_API std::string detail::grouping_impl<char>(locale_ref);
+template FMT_API char detail::thousands_sep_impl(locale_ref);
+template FMT_API char detail::decimal_point_impl(locale_ref);
 
-template FMT_API void internal::buffer<char>::append(const char*, const char*);
+template FMT_API void detail::buffer<char>::append(const char*, const char*);
 
-template FMT_API void internal::arg_map<format_context>::init(
-    const basic_format_args<format_context>& args);
+template FMT_API void detail::vformat_to(
+    detail::buffer<char>&, string_view,
+    basic_format_args<FMT_BUFFER_CONTEXT(char)>, detail::locale_ref);
 
-template FMT_API std::string internal::vformat<char>(
-    string_view, basic_format_args<format_context>);
-
-template FMT_API format_context::iterator internal::vformat_to(
-    internal::buffer<char>&, string_view, basic_format_args<format_context>);
-
-template FMT_API int internal::snprintf_float(double, int,
-                                              internal::float_specs,
-                                              internal::buffer<char>&);
-template FMT_API int internal::snprintf_float(long double, int,
-                                              internal::float_specs,
-                                              internal::buffer<char>&);
-template FMT_API int internal::format_float(double, int, internal::float_specs,
-                                            internal::buffer<char>&);
-template FMT_API int internal::format_float(long double, int,
-                                            internal::float_specs,
-                                            internal::buffer<char>&);
+template FMT_API int detail::snprintf_float(double, int, detail::float_specs,
+                                            detail::buffer<char>&);
+template FMT_API int detail::snprintf_float(long double, int,
+                                            detail::float_specs,
+                                            detail::buffer<char>&);
+template FMT_API int detail::format_float(double, int, detail::float_specs,
+                                          detail::buffer<char>&);
+template FMT_API int detail::format_float(long double, int, detail::float_specs,
+                                          detail::buffer<char>&);
 
 // Explicit instantiations for wchar_t.
 
-template FMT_API std::string internal::grouping_impl<wchar_t>(locale_ref);
-template FMT_API wchar_t internal::thousands_sep_impl(locale_ref);
-template FMT_API wchar_t internal::decimal_point_impl(locale_ref);
-
-template FMT_API void internal::buffer<wchar_t>::append(const wchar_t*,
-                                                        const wchar_t*);
+template FMT_API std::string detail::grouping_impl<wchar_t>(locale_ref);
+template FMT_API wchar_t detail::thousands_sep_impl(locale_ref);
+template FMT_API wchar_t detail::decimal_point_impl(locale_ref);
 
-template FMT_API std::wstring internal::vformat<wchar_t>(
-    wstring_view, basic_format_args<wformat_context>);
+template FMT_API void detail::buffer<wchar_t>::append(const wchar_t*,
+                                                      const wchar_t*);
 FMT_END_NAMESPACE
diff --git a/Externals/fmt/src/posix.cc b/Externals/fmt/src/os.cc
old mode 100755
new mode 100644
similarity index 63%
rename from Externals/fmt/src/posix.cc
rename to Externals/fmt/src/os.cc
index 3db72b76e251..a07e78244112
--- a/Externals/fmt/src/posix.cc
+++ b/Externals/fmt/src/os.cc
@@ -1,4 +1,4 @@
-// A C++ interface to POSIX functions.
+// Formatting library for C++ - optional OS-specific functionality
 //
 // Copyright (c) 2012 - 2016, Victor Zverovich
 // All rights reserved.
@@ -10,39 +10,43 @@
 #  define _CRT_SECURE_NO_WARNINGS
 #endif
 
-#include "fmt/posix.h"
+#include "fmt/os.h"
 
 #include <climits>
 
 #if FMT_USE_FCNTL
-#include <sys/stat.h>
-#include <sys/types.h>
-
-#ifndef _WIN32
-#  include <unistd.h>
-#else
-#  ifndef WIN32_LEAN_AND_MEAN
-#    define WIN32_LEAN_AND_MEAN
-#  endif
-#  include <io.h>
-#  include <windows.h>
+#  include <sys/stat.h>
+#  include <sys/types.h>
 
-#  define O_CREAT _O_CREAT
-#  define O_TRUNC _O_TRUNC
+#  ifndef _WIN32
+#    include <unistd.h>
+#  else
+#    ifndef WIN32_LEAN_AND_MEAN
+#      define WIN32_LEAN_AND_MEAN
+#    endif
+#    include <io.h>
+#    include <windows.h>
 
-#  ifndef S_IRUSR
-#    define S_IRUSR _S_IREAD
-#  endif
+#    define O_CREAT _O_CREAT
+#    define O_TRUNC _O_TRUNC
 
-#  ifndef S_IWUSR
-#    define S_IWUSR _S_IWRITE
-#  endif
+#    ifndef S_IRUSR
+#      define S_IRUSR _S_IREAD
+#    endif
 
-#  ifdef __MINGW32__
-#    define _SH_DENYNO 0x40
-#  endif
-#endif  // _WIN32
-#endif  // FMT_USE_FCNTL
+#    ifndef S_IWUSR
+#      define S_IWUSR _S_IWRITE
+#    endif
+
+#    ifdef __MINGW32__
+#      define _SH_DENYNO 0x40
+#    endif
+#  endif  // _WIN32
+#endif    // FMT_USE_FCNTL
+
+#ifdef _WIN32
+#  include <windows.h>
+#endif
 
 #ifdef fileno
 #  undef fileno
@@ -58,7 +62,7 @@ using RWResult = int;
 inline unsigned convert_rwcount(std::size_t count) {
   return count <= UINT_MAX ? static_cast<unsigned>(count) : UINT_MAX;
 }
-#else
+#elif FMT_USE_FCNTL
 // Return type of read and write functions.
 using RWResult = ssize_t;
 
@@ -68,6 +72,79 @@ inline std::size_t convert_rwcount(std::size_t count) { return count; }
 
 FMT_BEGIN_NAMESPACE
 
+#ifdef _WIN32
+detail::utf16_to_utf8::utf16_to_utf8(wstring_view s) {
+  if (int error_code = convert(s)) {
+    FMT_THROW(windows_error(error_code,
+                            "cannot convert string from UTF-16 to UTF-8"));
+  }
+}
+
+int detail::utf16_to_utf8::convert(wstring_view s) {
+  if (s.size() > INT_MAX) return ERROR_INVALID_PARAMETER;
+  int s_size = static_cast<int>(s.size());
+  if (s_size == 0) {
+    // WideCharToMultiByte does not support zero length, handle separately.
+    buffer_.resize(1);
+    buffer_[0] = 0;
+    return 0;
+  }
+
+  int length = WideCharToMultiByte(CP_UTF8, 0, s.data(), s_size, nullptr, 0,
+                                   nullptr, nullptr);
+  if (length == 0) return GetLastError();
+  buffer_.resize(length + 1);
+  length = WideCharToMultiByte(CP_UTF8, 0, s.data(), s_size, &buffer_[0],
+                               length, nullptr, nullptr);
+  if (length == 0) return GetLastError();
+  buffer_[length] = 0;
+  return 0;
+}
+
+void windows_error::init(int err_code, string_view format_str,
+                         format_args args) {
+  error_code_ = err_code;
+  memory_buffer buffer;
+  detail::format_windows_error(buffer, err_code, vformat(format_str, args));
+  std::runtime_error& base = *this;
+  base = std::runtime_error(to_string(buffer));
+}
+
+void detail::format_windows_error(detail::buffer<char>& out, int error_code,
+                                  string_view message) FMT_NOEXCEPT {
+  FMT_TRY {
+    wmemory_buffer buf;
+    buf.resize(inline_buffer_size);
+    for (;;) {
+      wchar_t* system_message = &buf[0];
+      int result = FormatMessageW(
+          FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS, nullptr,
+          error_code, MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), system_message,
+          static_cast<uint32_t>(buf.size()), nullptr);
+      if (result != 0) {
+        utf16_to_utf8 utf8_message;
+        if (utf8_message.convert(system_message) == ERROR_SUCCESS) {
+          format_to(buffer_appender<char>(out), "{}: {}", message,
+                    utf8_message);
+          return;
+        }
+        break;
+      }
+      if (GetLastError() != ERROR_INSUFFICIENT_BUFFER)
+        break;  // Can't get error message, report error code instead.
+      buf.resize(buf.size() * 2);
+    }
+  }
+  FMT_CATCH(...) {}
+  format_error_code(out, error_code, message);
+}
+
+void report_windows_error(int error_code,
+                          fmt::string_view message) FMT_NOEXCEPT {
+  report_error(detail::format_windows_error, error_code, message);
+}
+#endif  // _WIN32
+
 buffered_file::~buffered_file() FMT_NOEXCEPT {
   if (file_ && FMT_SYSTEM(fclose(file_)) != 0)
     report_system_error(errno, "cannot close file");
@@ -99,12 +176,12 @@ int buffered_file::fileno() const {
 #if FMT_USE_FCNTL
 file::file(cstring_view path, int oflag) {
   int mode = S_IRUSR | S_IWUSR;
-#if defined(_WIN32) && !defined(__MINGW32__)
+#  if defined(_WIN32) && !defined(__MINGW32__)
   fd_ = -1;
   FMT_POSIX_CALL(sopen_s(&fd_, path.c_str(), oflag, _SH_DENYNO, mode));
-#else
+#  else
   FMT_RETRY(fd_, FMT_POSIX_CALL(open(path.c_str(), oflag, mode)));
-#endif
+#  endif
   if (fd_ == -1)
     FMT_THROW(system_error(errno, "cannot open file {}", path.c_str()));
 }
@@ -126,7 +203,7 @@ void file::close() {
 }
 
 long long file::size() const {
-#ifdef _WIN32
+#  ifdef _WIN32
   // Use GetFileSize instead of GetFileSizeEx for the case when _WIN32_WINNT
   // is less than 0x0500 as is the case with some default MinGW builds.
   // Both functions support large file sizes.
@@ -140,7 +217,7 @@ long long file::size() const {
   }
   unsigned long long long_size = size_upper;
   return (long_size << sizeof(DWORD) * CHAR_BIT) | size_lower;
-#else
+#  else
   using Stat = struct stat;
   Stat file_stat = Stat();
   if (FMT_POSIX_CALL(fstat(fd_, &file_stat)) == -1)
@@ -148,21 +225,21 @@ long long file::size() const {
   static_assert(sizeof(long long) >= sizeof(file_stat.st_size),
                 "return type of file::size is not large enough");
   return file_stat.st_size;
-#endif
+#  endif
 }
 
 std::size_t file::read(void* buffer, std::size_t count) {
   RWResult result = 0;
   FMT_RETRY(result, FMT_POSIX_CALL(read(fd_, buffer, convert_rwcount(count))));
   if (result < 0) FMT_THROW(system_error(errno, "cannot read from file"));
-  return internal::to_unsigned(result);
+  return detail::to_unsigned(result);
 }
 
 std::size_t file::write(const void* buffer, std::size_t count) {
   RWResult result = 0;
   FMT_RETRY(result, FMT_POSIX_CALL(write(fd_, buffer, convert_rwcount(count))));
   if (result < 0) FMT_THROW(system_error(errno, "cannot write to file"));
-  return internal::to_unsigned(result);
+  return detail::to_unsigned(result);
 }
 
 file file::dup(int fd) {
@@ -195,15 +272,15 @@ void file::pipe(file& read_end, file& write_end) {
   read_end.close();
   write_end.close();
   int fds[2] = {};
-#ifdef _WIN32
+#  ifdef _WIN32
   // Make the default pipe capacity same as on Linux 2.6.11+.
   enum { DEFAULT_CAPACITY = 65536 };
   int result = FMT_POSIX_CALL(pipe(fds, DEFAULT_CAPACITY, _O_BINARY));
-#else
+#  else
   // Don't retry as the pipe function doesn't return EINTR.
   // http://pubs.opengroup.org/onlinepubs/009696799/functions/pipe.html
   int result = FMT_POSIX_CALL(pipe(fds));
-#endif
+#  endif
   if (result != 0) FMT_THROW(system_error(errno, "cannot create pipe"));
   // The following assignments don't throw because read_fd and write_fd
   // are closed.
@@ -212,8 +289,12 @@ void file::pipe(file& read_end, file& write_end) {
 }
 
 buffered_file file::fdopen(const char* mode) {
-  // Don't retry as fdopen doesn't return EINTR.
+// Don't retry as fdopen doesn't return EINTR.
+#  if defined(__MINGW32__) && defined(_POSIX_)
+  FILE* f = ::fdopen(fd_, mode);
+#  else
   FILE* f = FMT_POSIX_CALL(fdopen(fd_, mode));
+#  endif
   if (!f)
     FMT_THROW(
         system_error(errno, "cannot associate stream with file descriptor"));
@@ -223,15 +304,19 @@ buffered_file file::fdopen(const char* mode) {
 }
 
 long getpagesize() {
-#ifdef _WIN32
+#  ifdef _WIN32
   SYSTEM_INFO si;
   GetSystemInfo(&si);
   return si.dwPageSize;
-#else
+#  else
   long size = FMT_POSIX_CALL(sysconf(_SC_PAGESIZE));
   if (size < 0) FMT_THROW(system_error(errno, "cannot get memory page size"));
   return size;
-#endif
+#  endif
+}
+
+void ostream::grow(size_t) {
+  if (this->size() == this->capacity()) flush();
 }
 #endif  // FMT_USE_FCNTL
 FMT_END_NAMESPACE
diff --git a/Externals/fmt/support/README b/Externals/fmt/support/README
index e7fbacc73398..468f5485d9e4 100755
--- a/Externals/fmt/support/README
+++ b/Externals/fmt/support/README
@@ -2,5 +2,3 @@ This directory contains build support files such as
 
 * CMake modules
 * Build scripts
-* qmake (static build with dynamic libc only)
-
diff --git a/Externals/fmt/support/Vagrantfile b/Externals/fmt/support/Vagrantfile
index 24f166a109b3..f6b5f9366259 100644
--- a/Externals/fmt/support/Vagrantfile
+++ b/Externals/fmt/support/Vagrantfile
@@ -4,6 +4,7 @@
 # A vagrant config for testing against gcc-4.8.
 Vagrant.configure("2") do |config|
   config.vm.box = "ubuntu/xenial64"
+  config.disksize.size = '15GB'
 
   config.vm.provider "virtualbox" do |vb|
     vb.memory = "4096"
diff --git a/Externals/fmt/support/cmake/JoinPaths.cmake b/Externals/fmt/support/cmake/JoinPaths.cmake
new file mode 100644
index 000000000000..32d6d6685c06
--- /dev/null
+++ b/Externals/fmt/support/cmake/JoinPaths.cmake
@@ -0,0 +1,26 @@
+# This module provides function for joining paths
+# known from from most languages
+#
+# Original license:
+# SPDX-License-Identifier: (MIT OR CC0-1.0)
+# Explicit permission given to distribute this module under
+# the terms of the project as described in /LICENSE.rst.
+# Copyright 2020 Jan Tojnar
+# https://github.com/jtojnar/cmake-snips
+#
+# Modelled after Python’s os.path.join
+# https://docs.python.org/3.7/library/os.path.html#os.path.join
+# Windows not supported
+function(join_paths joined_path first_path_segment)
+    set(temp_path "${first_path_segment}")
+    foreach(current_segment IN LISTS ARGN)
+        if(NOT ("${current_segment}" STREQUAL ""))
+            if(IS_ABSOLUTE "${current_segment}")
+                set(temp_path "${current_segment}")
+            else()
+                set(temp_path "${temp_path}/${current_segment}")
+            endif()
+        endif()
+    endforeach()
+    set(${joined_path} "${temp_path}" PARENT_SCOPE)
+endfunction()
diff --git a/Externals/fmt/support/cmake/cxx14.cmake b/Externals/fmt/support/cmake/cxx14.cmake
index 032fcb270e0d..16ff57541b18 100755
--- a/Externals/fmt/support/cmake/cxx14.cmake
+++ b/Externals/fmt/support/cmake/cxx14.cmake
@@ -48,17 +48,6 @@ endif ()
 
 set(CMAKE_REQUIRED_FLAGS ${CXX_STANDARD_FLAG})
 
-# Check if variadic templates are working and not affected by GCC bug 39653:
-# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=39653
-# Can be removed once gcc 4.4 support is dropped.
-check_cxx_source_compiles("
-  template <class T, class ...Types>
-  struct S { typedef typename S<Types...>::type type; };
-  int main() {}" SUPPORTS_VARIADIC_TEMPLATES)
-if (NOT SUPPORTS_VARIADIC_TEMPLATES)
-  set (SUPPORTS_VARIADIC_TEMPLATES OFF)
-endif ()
-
 # Check if user-defined literals are available
 check_cxx_source_compiles("
   void operator\"\" _udl(long double);
diff --git a/Externals/fmt/support/cmake/fmt.pc.in b/Externals/fmt/support/cmake/fmt.pc.in
index e935dc78e118..29976a8af0b2 100755
--- a/Externals/fmt/support/cmake/fmt.pc.in
+++ b/Externals/fmt/support/cmake/fmt.pc.in
@@ -1,11 +1,11 @@
 prefix=@CMAKE_INSTALL_PREFIX@
 exec_prefix=@CMAKE_INSTALL_PREFIX@
-libdir=${exec_prefix}/@CMAKE_INSTALL_LIBDIR@
-includedir=${prefix}/@CMAKE_INSTALL_INCLUDEDIR@
+libdir=@libdir_for_pc_file@
+includedir=@includedir_for_pc_file@
 
 Name: fmt
 Description: A modern formatting library
 Version: @FMT_VERSION@
-Libs: -L${libdir} -lfmt
+Libs: -L${libdir} -l@FMT_LIB_NAME@
 Cflags: -I${includedir}
 
diff --git a/Externals/fmt/support/fmt.pro b/Externals/fmt/support/fmt.pro
deleted file mode 100755
index c555d0b4aeb6..000000000000
--- a/Externals/fmt/support/fmt.pro
+++ /dev/null
@@ -1,27 +0,0 @@
-# Staticlib configuration for qmake builds
-# For some reason qmake 3.1 fails to identify source dependencies and excludes format.cc and printf.cc
-# from compilation so it _MUST_ be called as qmake -nodepend
-# A workaround is implemented below: a custom compiler is defined which does not track dependencies
-
-TEMPLATE = lib
-
-TARGET = fmt
-
-QMAKE_EXT_CPP = .cc
-
-CONFIG = staticlib warn_on c++11
-
-FMT_SOURCES = \
-    ../src/format.cc \
-    ../src/posix.cc
-
-fmt.name = libfmt
-fmt.input = FMT_SOURCES
-fmt.output = ${QMAKE_FILE_BASE}$$QMAKE_EXT_OBJ
-fmt.clean = ${QMAKE_FILE_BASE}$$QMAKE_EXT_OBJ
-fmt.depends = ${QMAKE_FILE_IN}
-# QMAKE_RUN_CXX will not be expanded
-fmt.commands = $$QMAKE_CXX -c $$QMAKE_CXXFLAGS $$QMAKE_CXXFLAGS_WARN_ON $$QMAKE_CXXFLAGS_RELEASE_WITH_DEBUGINFO $$QMAKE_CXXFLAGS_CXX11 ${QMAKE_FILE_IN}
-fmt.variable_out = OBJECTS
-fmt.CONFIG = no_dependencies no_link
-QMAKE_EXTRA_COMPILERS += fmt
diff --git a/Externals/fmt/support/manage.py b/Externals/fmt/support/manage.py
index e39beff165ed..9f2706694002 100755
--- a/Externals/fmt/support/manage.py
+++ b/Externals/fmt/support/manage.py
@@ -137,15 +137,40 @@ def update_site(env):
         if not os.path.exists(contents):
             os.rename(os.path.join(target_doc_dir, 'index.rst'), contents)
         # Fix issues in reference.rst/api.rst.
-        for filename in ['reference.rst', 'api.rst']:
+        for filename in ['reference.rst', 'api.rst', 'index.rst']:
             pattern = re.compile('doxygenfunction.. (bin|oct|hexu|hex)$', re.M)
             with rewrite(os.path.join(target_doc_dir, filename)) as b:
                 b.data = b.data.replace('std::ostream &', 'std::ostream&')
                 b.data = re.sub(pattern, r'doxygenfunction:: \1(int)', b.data)
                 b.data = b.data.replace('std::FILE*', 'std::FILE *')
                 b.data = b.data.replace('unsigned int', 'unsigned')
-                b.data = b.data.replace('operator""_', 'operator"" _')
-                b.data = b.data.replace(', size_t', ', std::size_t')
+                #b.data = b.data.replace('operator""_', 'operator"" _')
+                b.data = b.data.replace(
+                    'format_to_n(OutputIt, size_t, string_view, Args&&',
+                    'format_to_n(OutputIt, size_t, const S&, const Args&')
+                b.data = b.data.replace(
+                    'format_to_n(OutputIt, std::size_t, string_view, Args&&',
+                    'format_to_n(OutputIt, std::size_t, const S&, const Args&')
+                if version == ('3.0.2'):
+                    b.data = b.data.replace(
+                        'fprintf(std::ostream&', 'fprintf(std::ostream &')
+                if version == ('5.3.0'):
+                    b.data = b.data.replace(
+                        'format_to(OutputIt, const S&, const Args&...)',
+                        'format_to(OutputIt, const S &, const Args &...)')
+                if version.startswith('5.') or version.startswith('6.'):
+                    b.data = b.data.replace(', size_t', ', std::size_t')
+                if version.startswith('7.'):
+                    b.data = b.data.replace(', std::size_t', ', size_t')
+                    b.data = b.data.replace('join(It, It', 'join(It, Sentinel')
+                b.data = b.data.replace('aa long', 'a long')
+                b.data = b.data.replace('serveral', 'several')
+                if version.startswith('6.2.'):
+                    b.data = b.data.replace(
+                        'vformat(const S&, basic_format_args<' +
+                        'buffer_context<Char>>)',
+                        'vformat(const S&, basic_format_args<' +
+                        'buffer_context<type_identity_t<Char>>>)')
         # Fix a broken link in index.rst.
         index = os.path.join(target_doc_dir, 'index.rst')
         with rewrite(index) as b:
diff --git a/Externals/fmt/support/update-coverity-branch.py b/Externals/fmt/support/update-coverity-branch.py
deleted file mode 100755
index 519f5d00d285..000000000000
--- a/Externals/fmt/support/update-coverity-branch.py
+++ /dev/null
@@ -1,30 +0,0 @@
-#!/usr/bin/env python
-# Update the coverity branch from the master branch.
-# It is not done automatically because Coverity Scan limits
-# the number of submissions per day.
-
-from __future__ import print_function
-import shutil, tempfile
-from subprocess import check_output, STDOUT
-
-class Git:
-    def __init__(self, dir):
-        self.dir = dir
-
-    def __call__(self, *args):
-        output = check_output(['git'] + list(args), cwd=self.dir, stderr=STDOUT)
-        print(output)
-        return output
-
-dir = tempfile.mkdtemp()
-try:
-    git = Git(dir)
-    git('clone', '-b', 'coverity', 'git@github.com:fmtlib/fmt.git', dir)
-    output = git('merge', '-X', 'theirs', '--no-commit', 'origin/master')
-    if 'Fast-forward' not in output:
-        git('reset', 'HEAD', '.travis.yml')
-        git('checkout', '--', '.travis.yml')
-        git('commit', '-m', 'Update coverity branch')
-    git('push')
-finally:
-    shutil.rmtree(dir)