libcxx/include/__math/traits.h

//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//

#ifndef _LIBCPP___MATH_TRAITS_H
#define _LIBCPP___MATH_TRAITS_H

#include <__config>
#include <__type_traits/enable_if.h>
#include <__type_traits/is_arithmetic.h>
#include <__type_traits/is_integral.h>
#include <__type_traits/promote.h>

#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
#  pragma GCC system_header
#endif

_LIBCPP_BEGIN_NAMESPACE_STD

namespace __math {

// signbit

// The universal C runtime (UCRT) in the WinSDK provides floating point overloads
// for std::signbit(). By defining our overloads as templates, we can work around
// this issue as templates are less preferred than non-template functions.
template <class = void>
[[__nodiscard__]] inline _LIBCPP_CONSTEXPR_SINCE_CXX23 _LIBCPP_HIDE_FROM_ABI bool signbit(float __x) _NOEXCEPT {
  return __builtin_signbit(__x);
}

template <class = void>
[[__nodiscard__]] inline _LIBCPP_CONSTEXPR_SINCE_CXX23 _LIBCPP_HIDE_FROM_ABI bool signbit(double __x) _NOEXCEPT {
  return __builtin_signbit(__x);
}

template <class = void>
[[__nodiscard__]] inline _LIBCPP_CONSTEXPR_SINCE_CXX23 _LIBCPP_HIDE_FROM_ABI bool signbit(long double __x) _NOEXCEPT {
  return __builtin_signbit(__x);
}

template <class _A1, __enable_if_t<is_integral<_A1>::value, int> = 0>
[[__nodiscard__]] inline _LIBCPP_CONSTEXPR_SINCE_CXX23 _LIBCPP_HIDE_FROM_ABI bool signbit(_A1 __x) _NOEXCEPT {
  return __x < 0;
}

// isfinite

template <class _A1, __enable_if_t<is_integral<_A1>::value, int> = 0>
[[__nodiscard__]] _LIBCPP_CONSTEXPR_SINCE_CXX23 _LIBCPP_HIDE_FROM_ABI bool isfinite(_A1) _NOEXCEPT {
  return true;
}

[[__nodiscard__]] inline _LIBCPP_CONSTEXPR_SINCE_CXX23 _LIBCPP_HIDE_FROM_ABI bool isfinite(float __x) _NOEXCEPT {
  return __builtin_isfinite(__x);
}

[[__nodiscard__]] inline _LIBCPP_CONSTEXPR_SINCE_CXX23 _LIBCPP_HIDE_FROM_ABI bool isfinite(double __x) _NOEXCEPT {
  return __builtin_isfinite(__x);
}

[[__nodiscard__]] inline _LIBCPP_CONSTEXPR_SINCE_CXX23 _LIBCPP_HIDE_FROM_ABI bool isfinite(long double __x) _NOEXCEPT {
  return __builtin_isfinite(__x);
}

// isinf

template <class _A1, __enable_if_t<is_integral<_A1>::value, int> = 0>
[[__nodiscard__]] _LIBCPP_CONSTEXPR_SINCE_CXX23 _LIBCPP_HIDE_FROM_ABI bool isinf(_A1) _NOEXCEPT {
  return false;
}

[[__nodiscard__]] inline _LIBCPP_CONSTEXPR_SINCE_CXX23 _LIBCPP_HIDE_FROM_ABI bool isinf(float __x) _NOEXCEPT {
  return __builtin_isinf(__x);
}

[[__nodiscard__]] inline _LIBCPP_CONSTEXPR_SINCE_CXX23 _LIBCPP_HIDE_FROM_ABI
#ifdef _LIBCPP_PREFERRED_OVERLOAD
_LIBCPP_PREFERRED_OVERLOAD
#endif
    bool
    isinf(double __x) _NOEXCEPT {
  return __builtin_isinf(__x);
}

[[__nodiscard__]] inline _LIBCPP_CONSTEXPR_SINCE_CXX23 _LIBCPP_HIDE_FROM_ABI bool isinf(long double __x) _NOEXCEPT {
  return __builtin_isinf(__x);
}

// isnan

template <class _A1, __enable_if_t<is_integral<_A1>::value, int> = 0>
[[__nodiscard__]] _LIBCPP_CONSTEXPR_SINCE_CXX23 _LIBCPP_HIDE_FROM_ABI bool isnan(_A1) _NOEXCEPT {
  return false;
}

[[__nodiscard__]] inline _LIBCPP_CONSTEXPR_SINCE_CXX23 _LIBCPP_HIDE_FROM_ABI bool isnan(float __x) _NOEXCEPT {
  return __builtin_isnan(__x);
}

[[__nodiscard__]] inline _LIBCPP_CONSTEXPR_SINCE_CXX23 _LIBCPP_HIDE_FROM_ABI
#ifdef _LIBCPP_PREFERRED_OVERLOAD
_LIBCPP_PREFERRED_OVERLOAD
#endif
    bool
    isnan(double __x) _NOEXCEPT {
  return __builtin_isnan(__x);
}

[[__nodiscard__]] inline _LIBCPP_CONSTEXPR_SINCE_CXX23 _LIBCPP_HIDE_FROM_ABI bool isnan(long double __x) _NOEXCEPT {
  return __builtin_isnan(__x);
}

// isnormal

template <class _A1, __enable_if_t<is_integral<_A1>::value, int> = 0>
[[__nodiscard__]] _LIBCPP_CONSTEXPR_SINCE_CXX23 _LIBCPP_HIDE_FROM_ABI bool isnormal(_A1 __x) _NOEXCEPT {
  return __x != 0;
}

[[__nodiscard__]] inline _LIBCPP_CONSTEXPR_SINCE_CXX23 _LIBCPP_HIDE_FROM_ABI bool isnormal(float __x) _NOEXCEPT {
  return __builtin_isnormal(__x);
}

[[__nodiscard__]] inline _LIBCPP_CONSTEXPR_SINCE_CXX23 _LIBCPP_HIDE_FROM_ABI bool isnormal(double __x) _NOEXCEPT {
  return __builtin_isnormal(__x);
}

[[__nodiscard__]] inline _LIBCPP_CONSTEXPR_SINCE_CXX23 _LIBCPP_HIDE_FROM_ABI bool isnormal(long double __x) _NOEXCEPT {
  return __builtin_isnormal(__x);
}

// isgreater

template <class _A1, class _A2, __enable_if_t<is_arithmetic<_A1>::value && is_arithmetic<_A2>::value, int> = 0>
[[__nodiscard__]] inline _LIBCPP_HIDE_FROM_ABI bool isgreater(_A1 __x, _A2 __y) _NOEXCEPT {
  using type = __promote_t<_A1, _A2>;
  return __builtin_isgreater((type)__x, (type)__y);
}

// isgreaterequal

template <class _A1, class _A2, __enable_if_t<is_arithmetic<_A1>::value && is_arithmetic<_A2>::value, int> = 0>
[[__nodiscard__]] inline _LIBCPP_HIDE_FROM_ABI bool isgreaterequal(_A1 __x, _A2 __y) _NOEXCEPT {
  using type = __promote_t<_A1, _A2>;
  return __builtin_isgreaterequal((type)__x, (type)__y);
}

// isless

template <class _A1, class _A2, __enable_if_t<is_arithmetic<_A1>::value && is_arithmetic<_A2>::value, int> = 0>
[[__nodiscard__]] inline _LIBCPP_HIDE_FROM_ABI bool isless(_A1 __x, _A2 __y) _NOEXCEPT {
  using type = __promote_t<_A1, _A2>;
  return __builtin_isless((type)__x, (type)__y);
}

// islessequal

template <class _A1, class _A2, __enable_if_t<is_arithmetic<_A1>::value && is_arithmetic<_A2>::value, int> = 0>
[[__nodiscard__]] inline _LIBCPP_HIDE_FROM_ABI bool islessequal(_A1 __x, _A2 __y) _NOEXCEPT {
  using type = __promote_t<_A1, _A2>;
  return __builtin_islessequal((type)__x, (type)__y);
}

// islessgreater

template <class _A1, class _A2, __enable_if_t<is_arithmetic<_A1>::value && is_arithmetic<_A2>::value, int> = 0>
[[__nodiscard__]] inline _LIBCPP_HIDE_FROM_ABI bool islessgreater(_A1 __x, _A2 __y) _NOEXCEPT {
  using type = __promote_t<_A1, _A2>;
  return __builtin_islessgreater((type)__x, (type)__y);
}

// isunordered

template <class _A1, class _A2, __enable_if_t<is_arithmetic<_A1>::value && is_arithmetic<_A2>::value, int> = 0>
[[__nodiscard__]] inline _LIBCPP_HIDE_FROM_ABI bool isunordered(_A1 __x, _A2 __y) _NOEXCEPT {
  using type = __promote_t<_A1, _A2>;
  return __builtin_isunordered((type)__x, (type)__y);
}

// MS UCRT incorrectly defines some functions in a way not working with integer types. Until C++20, this was worked
// around by -fdelayed-template-parsing. Since C++20, we can use standard feature "requires" instead.

// TODO: Remove the workaround once UCRT fixes these functions. Note that this doesn't seem planned as of 2025-07 per
// https://developercommunity.visualstudio.com/t/10294165.

#if defined(_LIBCPP_MSVCRT) && _LIBCPP_STD_VER >= 20
namespace __ucrt {
template <class _A1>
  requires is_integral_v<_A1>
[[nodiscard]] inline _LIBCPP_CONSTEXPR_SINCE_CXX23 _LIBCPP_HIDE_FROM_ABI bool isfinite(_A1) noexcept {
  return true;
}

template <class _A1>
  requires is_integral_v<_A1>
[[nodiscard]] inline _LIBCPP_CONSTEXPR_SINCE_CXX23 _LIBCPP_HIDE_FROM_ABI bool isinf(_A1) noexcept {
  return false;
}

template <class _A1>
  requires is_integral_v<_A1>
[[nodiscard]] inline _LIBCPP_CONSTEXPR_SINCE_CXX23 _LIBCPP_HIDE_FROM_ABI bool isnan(_A1) noexcept {
  return false;
}

template <class _A1>
  requires is_integral_v<_A1>
[[nodiscard]] inline _LIBCPP_CONSTEXPR_SINCE_CXX23 _LIBCPP_HIDE_FROM_ABI bool isnormal(_A1 __x) noexcept {
  return __x != 0;
}

template <class _A1, class _A2>
  requires is_arithmetic_v<_A1> && is_arithmetic_v<_A2>
[[nodiscard]] inline _LIBCPP_HIDE_FROM_ABI bool isgreater(_A1 __x, _A2 __y) noexcept {
  using type = __promote_t<_A1, _A2>;
  return __builtin_isgreater((type)__x, (type)__y);
}

template <class _A1, class _A2>
  requires is_arithmetic_v<_A1> && is_arithmetic_v<_A2>
[[nodiscard]] inline _LIBCPP_HIDE_FROM_ABI bool isgreaterequal(_A1 __x, _A2 __y) noexcept {
  using type = __promote_t<_A1, _A2>;
  return __builtin_isgreaterequal((type)__x, (type)__y);
}

template <class _A1, class _A2>
  requires is_arithmetic_v<_A1> && is_arithmetic_v<_A2>
[[nodiscard]] inline _LIBCPP_HIDE_FROM_ABI bool isless(_A1 __x, _A2 __y) noexcept {
  using type = __promote_t<_A1, _A2>;
  return __builtin_isless((type)__x, (type)__y);
}

template <class _A1, class _A2>
  requires is_arithmetic_v<_A1> && is_arithmetic_v<_A2>
[[nodiscard]] inline _LIBCPP_HIDE_FROM_ABI bool islessequal(_A1 __x, _A2 __y) noexcept {
  using type = __promote_t<_A1, _A2>;
  return __builtin_islessequal((type)__x, (type)__y);
}

template <class _A1, class _A2>
  requires is_arithmetic_v<_A1> && is_arithmetic_v<_A2>
[[nodiscard]] inline _LIBCPP_HIDE_FROM_ABI bool islessgreater(_A1 __x, _A2 __y) noexcept {
  using type = __promote_t<_A1, _A2>;
  return __builtin_islessgreater((type)__x, (type)__y);
}

template <class _A1, class _A2>
  requires is_arithmetic_v<_A1> && is_arithmetic_v<_A2>
[[nodiscard]] inline _LIBCPP_HIDE_FROM_ABI bool isunordered(_A1 __x, _A2 __y) noexcept {
  using type = __promote_t<_A1, _A2>;
  return __builtin_isunordered((type)__x, (type)__y);
}
} // namespace __ucrt
#endif

} // namespace __math

_LIBCPP_END_NAMESPACE_STD

#endif // _LIBCPP___MATH_TRAITS_H