fast_float/include/fast_float/constexpr_feature_detect.h

124 lines
3.7 KiB
C++

#ifndef FASTFLOAT_CONSTEXPR_FEATURE_DETECT_H
#define FASTFLOAT_CONSTEXPR_FEATURE_DETECT_H
#ifdef __has_include
#if __has_include(<version>)
#include <version>
#endif
#endif
// C++14 constexpr
#if defined(_MSC_VER)
#if _MSVC_LANG >= 201402L
#define FASTFLOAT_CONSTEXPR14 constexpr
#else
#define FASTFLOAT_CONSTEXPR14
#endif
#elif defined(__cpp_constexpr) && __cpp_constexpr >= 201304L
#define FASTFLOAT_CONSTEXPR14 constexpr
#elif __cplusplus >= 201402L
#define FASTFLOAT_CONSTEXPR14 constexpr
#else
#define FASTFLOAT_CONSTEXPR14
#endif
// C++14 variable templates
#if defined(__cpp_variable_templates) && __cpp_variable_templates >= 201304L
#define FASTFLOAT_HAS_VARIABLE_TEMPLATES 1
#elif __cplusplus >= 201402L
#define FASTFLOAT_HAS_VARIABLE_TEMPLATES 1
#elif defined(_MSC_FULL_VER) && _MSC_FULL_VER >= 190023918L && \
_MSVC_LANG >= 201402L
#define FASTFLOAT_HAS_VARIABLE_TEMPLATES 1
#else
#define FASTFLOAT_HAS_VARIABLE_TEMPLATES 0
#endif
// C++20 std::bit_cast
#if defined(__cpp_lib_bit_cast) && __cpp_lib_bit_cast >= 201806L
#define FASTFLOAT_HAS_BIT_CAST 1
#else
#define FASTFLOAT_HAS_BIT_CAST 0
#endif
// Detect consteval, C++20 constexpr extensions and std::is_constant_evaluated.
#if !defined(__cpp_lib_is_constant_evaluated)
#define FASTFLOAT__USE_CONSTEVAL 0
#elif __cplusplus < 201709L
#define FASTFLOAT_USE_CONSTEVAL 0
#elif defined(__apple_build_version__) && __apple_build_version__ < 14000029L
#define FASTFLOAT_USE_CONSTEVAL 0 // consteval is broken in Apple clang < 14.
#elif _MSC_VER && _MSC_VER < 1940
#define FASTFLOAT_USE_CONSTEVAL \
0 // consteval is broken in some MSVC2022 versions.
#elif defined(__cpp_consteval)
#define FASTFLOAT_USE_CONSTEVAL 1
#elif defined(__cpp_lib_is_constant_evaluated) && \
__cpp_lib_is_constant_evaluated >= 201811L
#define FASTFLOAT_USE_CONSTEVAL 1
#elif FMT_GCC_VERSION >= 1002 || FMT_CLANG_VERSION >= 1101
#define FASTFLOAT_USE_CONSTEVAL 1
#else
#define FASTFLOAT_USE_CONSTEVAL 0
#endif
#if FASTFLOAT_USE_CONSTEVAL
#define FASTFLOAT_CONSTEVAL consteval
#define FASTFLOAT_CONSTEXPR20 constexpr
#else
#define FASTFLOAT_CONSTEVAL
#define FASTFLOAT_CONSTEXPR20
#endif
#if defined(__cpp_lib_byteswap)
#define FASTFLOAT_HAS_BYTESWAP 1
#else
#define FASTFLOAT_HAS_BYTESWAP 0
#endif
// C++17 if constexpr
#if defined(__cpp_if_constexpr) && __cpp_if_constexpr >= 201606L
#define FASTFLOAT_CONSTEXPR17 constexpr
#elif defined(__cpp_constexpr) && __cpp_constexpr >= 201603L
#define FASTFLOAT_CONSTEXPR17 constexpr
#elif __cplusplus >= 201703L
#define FASTFLOAT_CONSTEXPR17 constexpr
#elif defined(_MSC_VER) && _MSC_VER >= 1911 && _MSVC_LANG >= 201703L
#define FASTFLOAT_CONSTEXPR17 constexpr
#else
#define FASTFLOAT_CONSTEXPR17
#endif
// C++17 inline variables
#if defined(__cpp_inline_variables) && __cpp_inline_variables >= 201606L
#define FASTFLOAT_INLINE_VARIABLE inline constexpr
#elif __cplusplus >= 201703L
#define FASTFLOAT_INLINE_VARIABLE inline constexpr
#elif defined(_MSC_VER) && _MSC_VER >= 1912 && _MSVC_LANG >= 201703L
#define FASTFLOAT_INLINE_VARIABLE inline constexpr
#else
#define FASTFLOAT_INLINE_VARIABLE static constexpr
#endif
#if __cplusplus >= 201703L || (defined(_MSVC_LANG) && _MSVC_LANG >= 201703L)
#define FASTFLOAT_DETAIL_MUST_DEFINE_CONSTEXPR_VARIABLE 0
#else
#define FASTFLOAT_DETAIL_MUST_DEFINE_CONSTEXPR_VARIABLE 1
#endif
#if defined(__has_builtin)
#define FASTFLOAT_HAS_BUILTIN(x) __has_builtin(x)
#else
#define FASTFLOAT_HAS_BUILTIN(x) false
#endif
#if defined(FASTFLOAT_ASSUME)
// user provided solution
#elif defined(__cpp_attrubute_assume)
// For support attribute [[assume]] is declared in P1774
#define FASTFLOAT_ASSUME(expr) [[assume(expr)]]
#else
#define FASTFLOAT_ASSUME(expr)
#endif
#endif // FASTFLOAT_CONSTEXPR_FEATURE_DETECT_H