Number: Add {std,fast_float}::from_chars wrappers

CMakeLists.txt

@@ -109,6 +109,7 @@ suboption(USE_LTO "Use link-time code generation" BOOL ${default_USE_LTO})
 suboption(WERROR "Turn warnings into errors" BOOL ${CONTINUOUS_INTEGRATION})
 
 suboption(CXX_STD_VERSION "Maximum C++ standard version to enable" STRING 2017)
+option(USE_CXX17_FROM_CHARS_FLOAT "Use std::from_chars(float) instead of fast_float::from_chars" OFF)
 if(DEVELOPER OR CMAKE_BUILD_TYPE STREQUAL "Debug")
 	set(default_DEBUG ON)
 else()
@@ -639,9 +640,15 @@ endif()
 
 if(NOT CXX_STD_VERSION LESS 2011)
 	enable_cxx_version(${CXX_STD_VERSION})
-	if(WIN32)
-		check_cxx17("std::fstream(wchar*)" ARX_HAVE_CXX17_FSTREAM_WCHAR ALWAYS)
-	endif()
+endif()
+if(WIN32)
+	check_cxx17("std::fstream(wchar*)" ARX_HAVE_CXX17_FSTREAM_WCHAR ALWAYS)
+endif()
+check_cxx17("std::from_chars(int)" ARX_HAVE_CXX17_FROM_CHARS_INT 1914)
+if(USE_CXX17_FROM_CHARS_FLOAT)
+	check_cxx17("std::from_chars(float)" ARX_HAVE_CXX17_FROM_CHARS_FLOAT 1924)
+else()
+	set(ARX_HAVE_CXX17_FROM_CHARS_FLOAT 0)
 endif()
 
 if(MSVC)
@@ -1233,6 +1240,7 @@ set(SCRIPT_SOURCES
 )
 
 set(UTIL_SOURCES
+	src/util/Number.cpp
 	src/util/String.cpp
 )
 
@@ -1392,6 +1400,10 @@ endif()
 
 list(APPEND ARX_LIBRARIES ${BASE_LIBRARIES})
 
+if(NOT ARX_HAVE_CXX17_FROM_CHARS_FLOAT)
+	include_directories(SYSTEM thirdparty/fast_float/include)
+endif()
+
 if(NOT MSVC)
 	check_link_library(Boost Boost_LIBRARIES)
 endif()

cmake/check/cxx17-std-from_chars-float.cpp

@@ -0,0 +1,17 @@
+
+#include <charconv>
+#include <string_view>
+
+int main(int argc, const char * argv[]) {
+
+	if(argc < 1) {
+		return 0;
+	}
+
+	std::string_view string(argv[0]);
+
+	float result = 0.f;
+	std::from_chars(string.data(), string.data() + string.length(), result);
+
+	return static_cast<int>(result);
+}

cmake/check/cxx17-std-from_chars-int.cpp

@@ -0,0 +1,18 @@
+
+#include <charconv>
+#include <string_view>
+#include <cstddef>
+
+int main(int argc, const char * argv[]) {
+
+	if(argc < 1) {
+		return 0;
+	}
+
+	std::string_view string(argv[0]);
+
+	std::int32_t result = 0;
+	std::from_chars(string.data(), string.data() + string.length(), result);
+
+	return static_cast<int>(result);
+}

src/platform/PlatformConfig.h.in

@@ -12,6 +12,10 @@
 // C++17 features
 // wide character support for filenames in fstream
 #cmakedefine01 ARX_HAVE_CXX17_FSTREAM_WCHAR
+// std::from_chars(float)
+#cmakedefine01 ARX_HAVE_CXX17_FROM_CHARS_FLOAT
+// std::from_chars(int)
+#cmakedefine01 ARX_HAVE_CXX17_FROM_CHARS_INT
 
 // GCC extensions
 // __attribute__((alloc_align(i)))

src/util/Number.cpp

@@ -0,0 +1,107 @@
+/*
+ * Copyright 2022 Arx Libertatis Team (see the AUTHORS file)
+ *
+ * This file is part of Arx Libertatis.
+ *
+ * Arx Libertatis is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * Arx Libertatis is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with Arx Libertatis.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "util/Number.h"
+
+#include "platform/PlatformConfig.h"
+
+#if ARX_HAVE_CXX17_FROM_CHARS_INT ||ARX_HAVE_CXX17_FROM_CHARS_FLOAT
+#include <charconv>
+#endif
+
+#if !ARX_HAVE_CXX17_FROM_CHARS_INT
+#include "boost/lexical_cast.hpp"
+#endif
+
+#if !ARX_HAVE_CXX17_FROM_CHARS_FLOAT
+#include "fast_float/fast_float.h"
+#endif
+
+#include "util/String.h"
+
+
+namespace util {
+
+//! Convert the start of string to a float similar to \ref atoi
+[[nodiscard]] std::optional<s32> toInt(std::string_view string, bool allowTrailingGarbage) noexcept {
+
+	if(!string.empty() && string[0] == '+') {
+		string.remove_prefix(1);
+	}
+
+	#if ARX_HAVE_CXX17_FROM_CHARS_INT
+	s32 value{};
+	auto result = std::from_chars(string.data(), string.data() + string.length(), value);
+  if(result.ec == std::errc() && (allowTrailingGarbage || result.ptr == string.data() + string.length())) {
+		return value;
+	} else {
+		return { };
+	}
+	#else
+	if(allowTrailingGarbage) {
+		size_t end = 0;
+		if(end != string.length() && string[end] == '-') {
+			end++;
+		}
+		if(end != string.length() && string[end] >= '0' && string[end] <= '9') {
+			end++;
+		}
+		string = string.substr(0, end);
+	}
+	try {
+		return boost::lexical_cast<s32>(string);
+	} catch(...) {
+		return { };
+	}
+	#endif
+
+}
+
+//! Convert the start of string to a float similar to \ref atof
+[[nodiscard]] std::optional<float> toFloat(std::string_view string, bool allowTrailingGarbage) noexcept {
+
+	if(!string.empty() && string[0] == '+') {
+		string.remove_prefix(1);
+	}
+
+	float value{};
+
+	#if ARX_HAVE_CXX17_FROM_CHARS_FLOAT
+	auto result = std::from_chars(string.data(), string.data() + string.length(), value);
+	#else
+	auto result = fast_float::from_chars(string.data(), string.data() + string.length(), value);
+	#endif
+
+	if(result.ec == std::errc() && (allowTrailingGarbage || result.ptr == string.data() + string.length())) {
+		return value;
+	} else {
+		return { };
+	}
+
+}
+
+s32 parseInt(std::string_view string) noexcept {
+	return toInt(trimLeft(string), true).value_or(0);
+}
+
+float parseFloat(std::string_view string) noexcept {
+	return toFloat(trimLeft(string), true).value_or(0.f);
+}
+
+} // namespace util

src/util/Number.h

@@ -0,0 +1,44 @@
+/*
+ * Copyright 2022 Arx Libertatis Team (see the AUTHORS file)
+ *
+ * This file is part of Arx Libertatis.
+ *
+ * Arx Libertatis is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * Arx Libertatis is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with Arx Libertatis.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef ARX_UTIL_NUMBER_H
+#define ARX_UTIL_NUMBER_H
+
+#include <optional>
+#include <string_view>
+
+#include "platform/Platform.h"
+
+namespace util {
+
+//! Convert the start of string to a float similar to \ref atoi but don't allow leading whitespace
+[[nodiscard]] std::optional<s32> toInt(std::string_view string, bool allowTrailingGarbage = false) noexcept;
+
+//! Convert the start of string to a float similar to \ref atof but don't allow leading whitespace
+[[nodiscard]] std::optional<float> toFloat(std::string_view string, bool allowTrailingGarbage = false) noexcept;
+
+//! Convert the start of string to a float similar to \ref atoi
+[[nodiscard]] s32 parseInt(std::string_view string) noexcept;
+
+//! Convert the start of string to a float similar to \ref atof
+[[nodiscard]] float parseFloat(std::string_view string) noexcept;
+
+} // namespace util
+
+#endif // ARX_UTIL_NUMBER_H

src/util/String.cpp

@@ -84,5 +84,4 @@ std::string getDateTimeString() {
 	return localTimeString.str();
 }
 
-
 } // namespace util