WIP: New C core (#870)

* Initial merge of C core library
* includes exrinfo, similar to exrheader (subject to removal before release)
* introduces the idea of an encoding and decoding pipeline which should enable future gpu or other custom paths

Signed-off-by: Kimball Thurston <kdt3rd@gmail.com>

* Comments, testing, and small fixes

Signed-off-by: Kimball Thurston <kdt3rd@gmail.com>
Co-authored-by: Timothy Grant <tgrant@nvidia.com>

.clang-format

@@ -32,7 +32,7 @@ BraceWrapping:
   AfterObjCDeclaration: true
   AfterStruct:     true
   AfterUnion:      true
-  AfterExternBlock: true
+  AfterExternBlock: false
   BeforeCatch:     true
   BeforeElse:      true
   IndentBraces:    false

cmake/CMakeLists.txt

@@ -64,6 +64,11 @@ else()
   set(OPENEXR_ENABLE_API_VISIBILITY ON)
 endif()
 
+if (UNIX AND NOT APPLE AND NOT BEOS)
+  find_library(OPENEXR_EXTRA_MATH_LIB m)
+  mark_as_advanced(OPENEXR_EXTRA_MATH_LIB)
+endif()
+
 configure_file(OpenEXRConfig.h.in ${CMAKE_CURRENT_BINARY_DIR}/OpenEXRConfig.h)
 configure_file(OpenEXRConfigInternal.h.in ${CMAKE_CURRENT_BINARY_DIR}/OpenEXRConfigInternal.h)
 

cmake/OpenEXRSetup.cmake

@@ -249,19 +249,25 @@ endif()
 # Find or install Imath
 #######################################
 
+option(OPENEXR_FORCE_INTERNAL_IMATH "Force using an internal imath" OFF)
 # Check to see if Imath is installed outside of the current build directory.
 set(IMATH_REPO "https://github.com/AcademySoftwareFoundation/Imath.git" CACHE STRING
     "Repo for auto-build of Imath")
 set(IMATH_TAG "master" CACHE STRING
-    "Tag for auto-build of Imath (branch, tag, or SHA)")
-#TODO: ^^ Release should not clone from master, this is a place holder
-set(CMAKE_IGNORE_PATH "${CMAKE_CURRENT_BINARY_DIR}/_deps/imath-src/config;${CMAKE_CURRENT_BINARY_DIR}/_deps/imath-build/config")
-find_package(Imath QUIET)
-set(CMAKE_IGNORE_PATH)
+  "Tag for auto-build of Imath (branch, tag, or SHA)")
+if(NOT OPENEXR_FORCE_INTERNAL_IMATH)
+  #TODO: ^^ Release should not clone from master, this is a place holder
+  set(CMAKE_IGNORE_PATH "${CMAKE_CURRENT_BINARY_DIR}/_deps/imath-src/config;${CMAKE_CURRENT_BINARY_DIR}/_deps/imath-build/config")
+  find_package(Imath QUIET)
+  set(CMAKE_IGNORE_PATH)
+endif()
 
 if(NOT TARGET Imath::Imath AND NOT Imath_FOUND)
-  message(STATUS "Imath was not found, installing from ${IMATH_REPO} (${IMATH_TAG})")
-
+  if(OPENEXR_FORCE_INTERNAL_IMATH)
+    message(STATUS "Imath forced internal, installing from ${IMATH_REPO} (${IMATH_TAG})")
+  else()
+    message(STATUS "Imath was not found, installing from ${IMATH_REPO} (${IMATH_TAG})")
+  endif()
   include(FetchContent)
   FetchContent_Declare(Imath
     GIT_REPOSITORY ${IMATH_REPO}
@@ -275,6 +281,16 @@ if(NOT TARGET Imath::Imath AND NOT Imath_FOUND)
     # hrm, cmake makes Imath lowercase for the properties (to imath)
     add_subdirectory(${imath_SOURCE_DIR} ${imath_BINARY_DIR})
   endif()
+  # the install creates this but if we're using the library locally we
+  # haven't installed the header files yet, so need to extract those
+  # and make a variable for header only usage
+  if(NOT TARGET Imath::ImathConfig)
+    get_target_property(imathinc Imath INTERFACE_INCLUDE_DIRECTORIES)
+    get_target_property(imathconfinc ImathConfig INTERFACE_INCLUDE_DIRECTORIES)
+    list(APPEND imathinc ${imathconfinc})
+    set(IMATH_HEADER_ONLY_INCLUDE_DIRS ${imathinc})
+    message(STATUS "Imath interface dirs ${IMATH_HEADER_ONLY_INCLUDE_DIRS}")
+  endif()
 else()
   message(STATUS "Using Imath from ${Imath_DIR}")
 endif()

src/bin/CMakeLists.txt

@@ -7,6 +7,7 @@
 if(OPENEXR_BUILD_TOOLS)
   add_subdirectory( exr2aces )
   add_subdirectory( exrheader )
+  add_subdirectory( exrinfo )
   add_subdirectory( exrmaketiled )
   add_subdirectory( exrstdattr )
   add_subdirectory( exrmakepreview )

src/bin/exrinfo/CMakeLists.txt

@@ -0,0 +1,12 @@
+# SPDX-License-Identifier: BSD-3-Clause
+# Copyright Contributors to the OpenEXR Project.
+
+add_executable(exrinfo main.c)
+target_link_libraries(exrinfo OpenEXR::OpenEXRCore)
+set_target_properties(exrinfo PROPERTIES
+  RUNTIME_OUTPUT_DIRECTORY "${CMAKE_BINARY_DIR}/bin"
+)
+install(TARGETS exrinfo DESTINATION ${CMAKE_INSTALL_BINDIR})
+if(WIN32 AND (BUILD_SHARED_LIBS OR OPENEXR_BUILD_BOTH_STATIC_SHARED))
+  target_compile_definitions(exrinfo PRIVATE OPENEXR_DLL)
+endif()

src/bin/exrinfo/main.c

@@ -0,0 +1,149 @@
+/*
+** SPDX-License-Identifier: BSD-3-Clause
+** Copyright Contributors to the OpenEXR Project.
+*/
+
+#include <openexr.h>
+#include <stdio.h>
+#include <string.h>
+
+#ifdef _WIN32
+#    include <fcntl.h>
+#    include <io.h>
+#    include <windows.h>
+#else
+#    include <unistd.h>
+#endif
+
+#include <stdlib.h>
+
+static void
+usage (const char* argv0)
+{
+    fprintf (
+        stderr,
+        "Usage: %s [-v|--verbose] <filename> [<filename> ...]\n\n",
+        argv0);
+}
+
+static void
+error_handler_cb (exr_const_context_t f, int code, const char* msg)
+{
+    const char* fn;
+    if (EXR_ERR_SUCCESS != exr_get_file_name (f, &fn)) fn = "<error>";
+    fprintf (
+        stderr,
+        "ERROR '%s' (%s): %s\n",
+        fn,
+        exr_get_error_code_as_string (code),
+        msg);
+}
+
+static int64_t
+stdin_reader (
+    exr_const_context_t         file,
+    void*                       userdata,
+    void*                       buffer,
+    uint64_t                    sz,
+    uint64_t                    offset,
+    exr_stream_error_func_ptr_t error_cb)
+{
+    static uint64_t lastoffset = 0;
+    int64_t         nread      = 0;
+
+    (void) userdata;
+
+    if (offset != lastoffset)
+    {
+        error_cb (file, EXR_ERR_READ_IO, "Unable to seek in stdin stream");
+        return -1;
+    }
+#ifdef _WIN32
+    if (sz >= (size_t) (INT32_MAX))
+    {
+        error_cb (
+            file, EXR_ERR_READ_IO, "Read request too large for win32 API");
+        return -1;
+    }
+    nread = _read (_fileno (stdin), buffer, (unsigned) sz);
+#else
+    nread = read (STDIN_FILENO, buffer, sz);
+#endif
+    if (nread > 0) lastoffset = offset + (uint64_t) nread;
+    return nread;
+}
+
+static int
+process_stdin (int verbose)
+{
+    int                       rv;
+    exr_context_t             e     = NULL;
+    exr_context_initializer_t cinit = EXR_DEFAULT_CONTEXT_INITIALIZER;
+    cinit.error_handler_fn          = &error_handler_cb;
+    cinit.read_fn                   = &stdin_reader;
+
+#ifdef _WIN32
+    _setmode (_fileno (stdin), _O_BINARY);
+#endif
+    rv = exr_start_read (&e, "<stdin>", &cinit);
+    if (rv == EXR_ERR_SUCCESS)
+    {
+        exr_print_context_info (e, verbose);
+        exr_finish (&e);
+    }
+    return rv;
+}
+
+static int
+process_file (const char* filename, int verbose)
+{
+    int                       rv;
+    exr_context_t             e     = NULL;
+    exr_context_initializer_t cinit = EXR_DEFAULT_CONTEXT_INITIALIZER;
+    cinit.error_handler_fn          = &error_handler_cb;
+
+    rv = exr_start_read (&e, filename, &cinit);
+    if (rv == 0)
+    {
+        exr_print_context_info (e, verbose);
+        exr_finish (&e);
+    }
+    return rv;
+}
+
+int
+main (int argc, const char* argv[])
+{
+    int rv = 0, nfiles = 0, verbose = 0;
+
+    for (int a = 1; a < argc; ++a)
+    {
+        if (!strcmp (argv[a], "-h") || !strcmp (argv[a], "-?") ||
+            !strcmp (argv[a], "--help"))
+        {
+            usage (argv[0]);
+            return 0;
+        }
+        else if (!strcmp (argv[a], "-v") || !strcmp (argv[a], "--verbose"))
+        {
+            verbose = 1;
+        }
+        else if (!strcmp (argv[a], "-"))
+        {
+            ++nfiles;
+            rv += process_stdin (verbose);
+        }
+        else if (argv[a][0] == '-')
+        {
+            usage (argv[0]);
+            return 1;
+        }
+        else
+        {
+            ++nfiles;
+            rv += process_file (argv[a], verbose);
+        }
+    }
+
+    return rv;
+}

src/lib/CMakeLists.txt

@@ -4,5 +4,6 @@
 add_subdirectory( Iex )
 add_subdirectory( IlmThread )
 
+add_subdirectory( OpenEXRCore )
 add_subdirectory( OpenEXR )
 add_subdirectory( OpenEXRUtil )

src/lib/OpenEXRCore/CMakeLists.txt

@@ -0,0 +1,95 @@
+# SPDX-License-Identifier: BSD-3-Clause
+# Copyright Contributors to the OpenEXR Project.
+
+openexr_define_library(OpenEXRCore
+  PRIV_EXPORT OPENEXRCORE_EXPORTS
+  CURDIR ${CMAKE_CURRENT_SOURCE_DIR}
+  SOURCES
+    #NB: If you make any of these public, make sure to update the
+    # locking macros in the relative source files
+    internal_attr.h
+    internal_channel_list.h
+    internal_coding.h
+    internal_constants.h
+    internal_compress.h
+    internal_decompress.h
+    internal_file.h
+    internal_float_vector.h
+    internal_memory.h
+    internal_opaque.h
+    internal_posix_file_impl.h
+    internal_win32_file_impl.h
+    internal_preview.h
+    internal_string.h
+    internal_string_vector.h
+    internal_structs.h
+    internal_xdr.h
+
+    internal_rle.c
+    internal_zip.c
+    internal_pxr24.c
+    internal_b44.c
+    internal_b44_table.c
+    internal_piz.c
+    internal_dwa.c
+    internal_huf.c
+
+    attributes.c
+    string.c
+    string_vector.c
+    float_vector.c
+    channel_list.c
+    opaque.c
+    preview.c
+
+    base.c
+    context.c
+    memory.c
+    internal_structs.c
+
+    part.c
+    part_attr.c
+    std_attr.c
+
+    parse_header.c
+    write_header.c
+
+    chunk.c
+    coding.c
+    decoding.c
+    encoding.c
+    pack.c
+    unpack.c
+    validation.c
+
+    debug.c
+
+  HEADERS
+    openexr.h
+
+    openexr_attr.h
+    openexr_base.h
+    openexr_chunkio.h
+    openexr_coding.h
+    openexr_conf.h
+    openexr_context.h
+    openexr_decode.h
+    openexr_debug.h
+    openexr_encode.h
+    openexr_errors.h
+    openexr_part.h
+    openexr_std_attr.h
+  DEPENDENCIES
+    ZLIB::ZLIB
+  PRIVATE_DEPS
+    ${OPENEXR_EXTRA_MATH_LIB}
+  )
+
+# when building with an internal imath, this isn't generated until
+# install time, so need to use private header only include path (we
+# aren't linking to imath or anything c++)
+if (TARGET Imath::ImathConfig)
+  target_link_libraries(OpenEXRCore PRIVATE Imath::ImathConfig)
+else()
+  target_include_directories(OpenEXRCore PRIVATE ${IMATH_HEADER_ONLY_INCLUDE_DIRS})
+endif()