added TOML_ENABLE_FLOAT16 config to fix #178

CHANGELOG.md

@@ -30,6 +30,7 @@ template:
 - fixed some `_Float16` detection issues
 - fixed `toml::parse_file()` on windows for non-ASCII paths
 - added `toml::format_flags::terse_key_value_pairs`
+- added `TOML_ENABLE_FLOAT16` config to fix #178 (@Scrumplex)
 
 <br><br>
 

README.md

@@ -209,6 +209,7 @@ won't need to mess with these at all, but if you do, set them before including t
 | `TOML_CALLCONV`                   |     define     | Calling convention to apply to exported free/static functions.                                           | undefined              |
 | `TOML_CONFIG_HEADER`              | string literal | Includes the given header file before the rest of the library.                                           | undefined              |
 | `TOML_ENABLE_FORMATTERS`          |     boolean    | Enables the formatters. Set to `0` if you don't need them to improve compile times and binary size.      | `1`                    |
+| `TOML_ENABLE_FLOAT16`             |     boolean    | Enables support for the built-in `_Float16` type.                                                        | per compiler settings  |
 | `TOML_ENABLE_PARSER`              |     boolean    | Enables the parser. Set to `0` if you don't need it to improve compile times and binary size.            | `1`                    |
 | `TOML_ENABLE_UNRELEASED_FEATURES` |     boolean    | Enables support for [unreleased TOML language features].                                                 | `0`                    |
 | `TOML_ENABLE_WINDOWS_COMPAT`      |     boolean    | Enables support for transparent conversion between wide and narrow strings.                              | `1` on Windows         |

include/toml++/impl/forward_declarations.h

@@ -628,9 +628,9 @@ TOML_IMPL_NAMESPACE_START
 	template <typename T>
 	struct float_traits : float_traits_base<T, std::numeric_limits<T>::digits, std::numeric_limits<T>::digits10>
 	{};
-#ifdef TOML_FLOAT16
+#if TOML_ENABLE_FLOAT16
 	template <>
-	struct float_traits<TOML_FLOAT16> : float_traits_base<TOML_FLOAT16, __FLT16_MANT_DIG__, __FLT16_DIG__>
+	struct float_traits<_Float16> : float_traits_base<_Float16, __FLT16_MANT_DIG__, __FLT16_DIG__>
 	{};
 #endif
 #ifdef TOML_FLOAT128
@@ -649,9 +649,9 @@ TOML_IMPL_NAMESPACE_START
 	template <>
 	struct value_traits<long double> : float_traits<long double>
 	{};
-#ifdef TOML_FLOAT16
+#if TOML_ENABLE_FLOAT16
 	template <>
-	struct value_traits<TOML_FLOAT16> : float_traits<TOML_FLOAT16>
+	struct value_traits<_Float16> : float_traits<_Float16>
 	{};
 #endif
 #ifdef TOML_FLOAT128

include/toml++/impl/preprocessor.h

@@ -1055,7 +1055,34 @@ TOML_ENABLE_WARNINGS;
 //# FLOAT16
 //#=====================================================================================================================
 
-#if TOML_CLANG
+#ifndef TOML_ENABLE_FLOAT16
+
+#ifdef __FLT16_MANT_DIG__
+#define TOML_FLOAT16_MANT_DIG	__FLT16_MANT_DIG__
+#define TOML_FLOAT16_DIG		__FLT16_DIG__
+#define TOML_FLOAT16_MIN_EXP	__FLT16_MIN_EXP__
+#define TOML_FLOAT16_MIN_10_EXP __FLT16_MIN_10_EXP__
+#define TOML_FLOAT16_MAX_EXP	__FLT16_MAX_EXP__
+#define TOML_FLOAT16_MAX_10_EXP __FLT16_MAX_10_EXP__
+#else
+#define TOML_FLOAT16_MANT_DIG	0
+#define TOML_FLOAT16_DIG		0
+#define TOML_FLOAT16_MIN_EXP	0
+#define TOML_FLOAT16_MIN_10_EXP 0
+#define TOML_FLOAT16_MAX_EXP	0
+#define TOML_FLOAT16_MAX_10_EXP 0
+#endif
+
+#if (TOML_FLOAT16_MANT_DIG && TOML_FLOAT16_DIG && TOML_FLOAT16_MIN_EXP && TOML_FLOAT16_MIN_10_EXP                      \
+	 && TOML_FLOAT16_MAX_EXP && TOML_FLOAT16_MAX_10_EXP)
+#define TOML_FLOAT16_LIMITS_SET 1
+#else
+#define TOML_FLOAT16_LIMITS_SET 0
+#endif
+
+#if TOML_FLOAT16_LIMITS_SET
+
+#if TOML_CLANG // >= 15
 //# {{
 //	Excerpt from https://clang.llvm.org/docs/LanguageExtensions.html:
 //
@@ -1069,9 +1096,10 @@ TOML_ENABLE_WARNINGS;
 //		X86 as long as SSE2 is available
 //
 //# }}
-#if (TOML_ARCH_ARM || TOML_ARCH_X86 || TOML_ARCH_AMD64) && defined(__FLT16_MANT_DIG__)
+#if (TOML_ARCH_ARM || TOML_ARCH_AMD64 || TOML_ARCH_X86)
-#define TOML_FLOAT16 _Float16
+#define TOML_ENABLE_FLOAT16 1
 #endif
+
 #elif TOML_GCC
 //# {{
 //	Excerpt from https://gcc.gnu.org/onlinedocs/gcc/Floating-Types.html:
@@ -1082,13 +1110,25 @@ TOML_ENABLE_WARNINGS;
 //
 //	*** except: the bit about x86 seems incorrect?? ***
 //# }}
-/*
+#if (TOML_ARCH_ARM || TOML_ARCH_AMD64 /* || TOML_ARCH_X86*/)
+#define TOML_ENABLE_FLOAT16 1
+#endif
 
- */
+#endif // clang/gcc
-#if (TOML_ARCH_ARM /*|| TOML_ARCH_X86 || TOML_ARCH_AMD64*/) && defined(__FLT16_MANT_DIG__)
+
-#define TOML_FLOAT16 _Float16
+#endif // TOML_FLOAT16_LIMITS_SET
-#endif
+
+#endif // !defined(TOML_ENABLE_FLOAT16)
+
+#ifndef TOML_ENABLE_FLOAT16
+#define TOML_ENABLE_FLOAT16 0
 #endif
+//# {{
+/// \def TOML_ENABLE_FLOAT16
+/// \brief Enable support for the built-in `_Float16` type.
+/// \detail Default behaviour is to try to determine support based on compiler, architecture and built-in defines, but
+/// you can override it to force-enable/disable support.
+//# }}
 
 //#=====================================================================================================================
 //# FLOAT128

include/toml++/toml.h

@@ -90,8 +90,8 @@ TOML_POP_WARNINGS;
 #undef TOML_ANON_NAMESPACE
 #undef TOML_ANON_NAMESPACE_END
 #undef TOML_ANON_NAMESPACE_START
-#undef TOML_ARCH_ARM
 #undef TOML_ARCH_AMD64
+#undef TOML_ARCH_ARM
 #undef TOML_ARCH_ARM32
 #undef TOML_ARCH_ARM64
 #undef TOML_ARCH_ITANIUM
@@ -131,7 +131,13 @@ TOML_POP_WARNINGS;
 #undef TOML_FLAGS_ENUM
 #undef TOML_FLOAT_CHARCONV
 #undef TOML_FLOAT128
-#undef TOML_FLOAT16
+#undef TOML_FLOAT16_DIG
+#undef TOML_FLOAT16_LIMITS_SET
+#undef TOML_FLOAT16_MANT_DIG
+#undef TOML_FLOAT16_MAX_10_EXP
+#undef TOML_FLOAT16_MAX_EXP
+#undef TOML_FLOAT16_MIN_10_EXP
+#undef TOML_FLOAT16_MIN_EXP
 #undef TOML_GCC
 #undef TOML_HAS_ATTR
 #undef TOML_HAS_BUILTIN

meson.build

@@ -319,27 +319,11 @@ compiler_supports_consteval_properly = compiler_supports_consteval and not compi
 )
 
 #######################################################################################################################
-# __fp16 and _Float16 checks
+# _Float16 checks
 #######################################################################################################################
 
-compiler_supports_float16_args = []
+compiler_supports_float16_args = compiler.get_supported_arguments('-mfp16-format=ieee')
-if is_gcc
+compiler_supports_float16 = get_option('float16') and compiler.links('''
-	compiler_supports_float16_args += '-mfp16-format=ieee'
-endif
-compiler_supports_fp16 = compiler.links('''
-	int main()
-	{
-		static_assert(sizeof(__fp16) == 2);
-		__fp16 f = static_cast<__fp16>(1);
-		const auto f2 = static_cast<float>(f);
-		const auto f3 = static_cast<__fp16>(0.2L);
-		return 0;
-	}
-	''',
-	name: 'supports __fp16',
-	args: compiler_supports_float16_args
-)
-compiler_supports_float16 = compiler.links('''
 	int main()
 	{
 		static_assert(sizeof(_Float16) == 2);
@@ -352,7 +336,7 @@ compiler_supports_float16 = compiler.links('''
 	name: 'supports _Float16',
 	args: compiler_supports_float16_args
 )
-if compiler_supports_fp16 or compiler_supports_float16
+if compiler_supports_float16
 	devel_args += compiler_supports_float16_args
 endif
 
@@ -411,8 +395,8 @@ compiler_supports_float128 = compiler.links('''
 	name: 'supports __float128'
 )
 
-if compiler_supports_float128 and is_gcc and not is_subproject
+if compiler_supports_float16 or compiler_supports_float128 or compiler_supports_int128
-	add_global_arguments('-fext-numeric-literals', language: 'cpp')
+	devel_args += compiler.get_supported_arguments('-fext-numeric-literals')
 endif
 
 #######################################################################################################################

meson_options.txt

@@ -11,3 +11,4 @@ option('build_tt_encoder',		type: 'boolean', value: false,	description: 'Enable
 option('build_tt_decoder',		type: 'boolean', value: false,	description: 'Enable to build the toml-test decoder.')
 option('compile_library',		type: 'boolean', value: false,	description: 'Compile as a library')
 option('use_vendored_libs',		type: 'boolean', value: true,	description: 'Use the libs from the vendor dir when building tests.')
+option('float16',				type: 'boolean', value: true,	description: 'Use _Float16 automatically where available.')

src/meson.build

@@ -6,6 +6,15 @@ lib_args = ['-DTOML_HEADER_ONLY=0']
 if get_option('default_library') != 'static'
 	lib_args += '-DTOML_SHARED_LIB=1'
 endif
+if compiler_supports_float16
+	lib_args += compiler_supports_float16_args
+	lib_args += '-DTOML_ENABLE_FLOAT16=1'
+else
+	lib_args += '-DTOML_ENABLE_FLOAT16=0'
+endif
+if compiler_supports_float16 or compiler_supports_float128 or compiler_supports_int128
+	lib_args += compiler.get_supported_arguments('-fext-numeric-literals')
+endif
 
 lib = library(
 	meson.project_name(),

tests/impl_toml.cpp

@@ -64,8 +64,8 @@ namespace toml
 	CHECK_CAN_REPRESENT_NATIVE(TOML_INT128, true);
 	CHECK_CAN_REPRESENT_NATIVE(TOML_UINT128, false);
 #endif
-#ifdef TOML_FLOAT16
+#if TOML_ENABLE_FLOAT16
-	CHECK_CAN_REPRESENT_NATIVE(TOML_FLOAT16, false);
+	CHECK_CAN_REPRESENT_NATIVE(_Float16, false);
 #endif
 #ifdef TOML_FLOAT128
 	CHECK_CAN_REPRESENT_NATIVE(TOML_FLOAT128, true);
@@ -289,8 +289,8 @@ namespace toml
 	CHECK_INSERTED_AS(uint32_t, value<int64_t>);
 	CHECK_INSERTED_AS(float, value<double>);
 	CHECK_INSERTED_AS(double, value<double>);
-#ifdef TOML_FLOAT16
+#if TOML_ENABLE_FLOAT16
-	CHECK_INSERTED_AS(TOML_FLOAT16, value<double>);
+	CHECK_INSERTED_AS(_Float16, value<double>);
 #endif
 
 #define CHECK_NODE_REF_TYPE(T)                                                                                         \

tests/meson.build

@@ -39,13 +39,7 @@ endif
 # fast math check
 #######################################################################################################################
 
-compiler_supports_fast_math_args = []
+compiler_supports_fast_math_args = compiler.get_supported_arguments('-ffast-math', '-ffp-contract=fast', '/fp:fast')
-if is_gcc or is_clang
-	compiler_supports_fast_math_args += '-ffast-math'
-	compiler_supports_fast_math_args += '-ffp-contract=fast'
-elif is_msvc or is_icc_cl
-	compiler_supports_fast_math_args += '/fp:fast'
-endif
 compiler_supports_fast_math = compiler.links('''
 	#include <cmath>
 	#include <iostream>
@@ -58,7 +52,6 @@ compiler_supports_fast_math = compiler.links('''
 	name: 'supports fast-math',
 	args: compiler_supports_fast_math_args
 )
-
 #######################################################################################################################
 # do the thing!
 #######################################################################################################################

tests/tests.h

@@ -11,8 +11,8 @@
 #else
 #include "../include/toml++/toml.h"
 #endif
-#if defined(TOML_FLOAT16) ^ SHOULD_HAVE_FLOAT16
+#if TOML_ENABLE_FLOAT16 ^ SHOULD_HAVE_FLOAT16
-#error TOML_FLOAT16 was not deduced correctly
+#error TOML_ENABLE_FLOAT16 was not deduced correctly
 #endif
 #if defined(TOML_FLOAT128) ^ SHOULD_HAVE_FLOAT128
 #error TOML_FLOAT128 was not deduced correctly

toml.hpp

@@ -930,17 +930,51 @@ TOML_ENABLE_WARNINGS;
 	TOML_REQUIRES(condition)
 #define TOML_HIDDEN_CONSTRAINT(condition, ...) TOML_CONSTRAINED_TEMPLATE(condition, __VA_ARGS__)
 
-#if TOML_CLANG
+#ifndef TOML_ENABLE_FLOAT16
-#if (TOML_ARCH_ARM || TOML_ARCH_X86 || TOML_ARCH_AMD64) && defined(__FLT16_MANT_DIG__)
-#define TOML_FLOAT16 _Float16
-#endif
-#elif TOML_GCC
-/*
 
- */
+#ifdef __FLT16_MANT_DIG__
-#if (TOML_ARCH_ARM /*|| TOML_ARCH_X86 || TOML_ARCH_AMD64*/) && defined(__FLT16_MANT_DIG__)
+#define TOML_FLOAT16_MANT_DIG	__FLT16_MANT_DIG__
-#define TOML_FLOAT16 _Float16
+#define TOML_FLOAT16_DIG		__FLT16_DIG__
+#define TOML_FLOAT16_MIN_EXP	__FLT16_MIN_EXP__
+#define TOML_FLOAT16_MIN_10_EXP __FLT16_MIN_10_EXP__
+#define TOML_FLOAT16_MAX_EXP	__FLT16_MAX_EXP__
+#define TOML_FLOAT16_MAX_10_EXP __FLT16_MAX_10_EXP__
+#else
+#define TOML_FLOAT16_MANT_DIG	0
+#define TOML_FLOAT16_DIG		0
+#define TOML_FLOAT16_MIN_EXP	0
+#define TOML_FLOAT16_MIN_10_EXP 0
+#define TOML_FLOAT16_MAX_EXP	0
+#define TOML_FLOAT16_MAX_10_EXP 0
 #endif
+
+#if (TOML_FLOAT16_MANT_DIG && TOML_FLOAT16_DIG && TOML_FLOAT16_MIN_EXP && TOML_FLOAT16_MIN_10_EXP                      \
+	 && TOML_FLOAT16_MAX_EXP && TOML_FLOAT16_MAX_10_EXP)
+#define TOML_FLOAT16_LIMITS_SET 1
+#else
+#define TOML_FLOAT16_LIMITS_SET 0
+#endif
+
+#if TOML_FLOAT16_LIMITS_SET
+
+#if TOML_CLANG // >= 15
+#if (TOML_ARCH_ARM || TOML_ARCH_AMD64 || TOML_ARCH_X86)
+#define TOML_ENABLE_FLOAT16 1
+#endif
+
+#elif TOML_GCC
+#if (TOML_ARCH_ARM || TOML_ARCH_AMD64 /* || TOML_ARCH_X86*/)
+#define TOML_ENABLE_FLOAT16 1
+#endif
+
+#endif // clang/gcc
+
+#endif // TOML_FLOAT16_LIMITS_SET
+
+#endif // !defined(TOML_ENABLE_FLOAT16)
+
+#ifndef TOML_ENABLE_FLOAT16
+#define TOML_ENABLE_FLOAT16 0
 #endif
 
 #if defined(__SIZEOF_FLOAT128__) && defined(__FLT128_MANT_DIG__) && defined(__LDBL_MANT_DIG__)                         \
@@ -1701,9 +1735,9 @@ TOML_IMPL_NAMESPACE_START
 	template <typename T>
 	struct float_traits : float_traits_base<T, std::numeric_limits<T>::digits, std::numeric_limits<T>::digits10>
 	{};
-#ifdef TOML_FLOAT16
+#if TOML_ENABLE_FLOAT16
 	template <>
-	struct float_traits<TOML_FLOAT16> : float_traits_base<TOML_FLOAT16, __FLT16_MANT_DIG__, __FLT16_DIG__>
+	struct float_traits<_Float16> : float_traits_base<_Float16, __FLT16_MANT_DIG__, __FLT16_DIG__>
 	{};
 #endif
 #ifdef TOML_FLOAT128
@@ -1722,9 +1756,9 @@ TOML_IMPL_NAMESPACE_START
 	template <>
 	struct value_traits<long double> : float_traits<long double>
 	{};
-#ifdef TOML_FLOAT16
+#if TOML_ENABLE_FLOAT16
 	template <>
-	struct value_traits<TOML_FLOAT16> : float_traits<TOML_FLOAT16>
+	struct value_traits<_Float16> : float_traits<_Float16>
 	{};
 #endif
 #ifdef TOML_FLOAT128
@@ -17091,8 +17125,8 @@ TOML_POP_WARNINGS;
 #undef TOML_ANON_NAMESPACE
 #undef TOML_ANON_NAMESPACE_END
 #undef TOML_ANON_NAMESPACE_START
-#undef TOML_ARCH_ARM
 #undef TOML_ARCH_AMD64
+#undef TOML_ARCH_ARM
 #undef TOML_ARCH_ARM32
 #undef TOML_ARCH_ARM64
 #undef TOML_ARCH_ITANIUM
@@ -17132,7 +17166,13 @@ TOML_POP_WARNINGS;
 #undef TOML_FLAGS_ENUM
 #undef TOML_FLOAT_CHARCONV
 #undef TOML_FLOAT128
-#undef TOML_FLOAT16
+#undef TOML_FLOAT16_DIG
+#undef TOML_FLOAT16_LIMITS_SET
+#undef TOML_FLOAT16_MANT_DIG
+#undef TOML_FLOAT16_MAX_10_EXP
+#undef TOML_FLOAT16_MAX_EXP
+#undef TOML_FLOAT16_MIN_10_EXP
+#undef TOML_FLOAT16_MIN_EXP
 #undef TOML_GCC
 #undef TOML_HAS_ATTR
 #undef TOML_HAS_BUILTIN

tools/generate_single_header.py

@@ -215,6 +215,7 @@ def main():
 				r'TOML_ENABLE_SIMD',
 				r'TOML_ENABLE_UNRELEASED_FEATURES',
 				r'TOML_ENABLE_WINDOWS_COMPAT',
+				r'TOML_ENABLE_FLOAT16',
 				r'TOML_EXCEPTIONS',
 				r'TOML_EXPORTED_CLASS',
 				r'TOML_EXPORTED_FREE_FUNCTION',