libcxx/include/__utility/cmp.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___UTILITY_CMP_H
#define _LIBCPP___UTILITY_CMP_H

#include <__config>
#include <__type_traits/integer_traits.h>
#include <__type_traits/is_signed.h>
#include <__type_traits/make_unsigned.h>
#include <limits>

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

_LIBCPP_PUSH_MACROS
#include <__undef_macros>

#if _LIBCPP_STD_VER >= 20

_LIBCPP_BEGIN_NAMESPACE_STD

template <typename _Tp, typename _Ip>
concept __comparison_can_promote_to =
    sizeof(_Tp) < sizeof(_Ip) || (sizeof(_Tp) == sizeof(_Ip) && __signed_integer<_Tp>);

template <__signed_or_unsigned_integer _Tp, __signed_or_unsigned_integer _Up>
[[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr bool cmp_equal(_Tp __t, _Up __u) noexcept {
  if constexpr (is_signed_v<_Tp> == is_signed_v<_Up>)
    return __t == __u;
  else if constexpr (__comparison_can_promote_to<_Tp, int> && __comparison_can_promote_to<_Up, int>)
    return static_cast<int>(__t) == static_cast<int>(__u);
  else if constexpr (__comparison_can_promote_to<_Tp, long long> && __comparison_can_promote_to<_Up, long long>)
    return static_cast<long long>(__t) == static_cast<long long>(__u);
  else if constexpr (is_signed_v<_Tp>)
    return __t < 0 ? false : make_unsigned_t<_Tp>(__t) == __u;
  else
    return __u < 0 ? false : __t == make_unsigned_t<_Up>(__u);
}

template <__signed_or_unsigned_integer _Tp, __signed_or_unsigned_integer _Up>
[[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr bool cmp_not_equal(_Tp __t, _Up __u) noexcept {
  return !std::cmp_equal(__t, __u);
}

template <__signed_or_unsigned_integer _Tp, __signed_or_unsigned_integer _Up>
[[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr bool cmp_less(_Tp __t, _Up __u) noexcept {
  if constexpr (is_signed_v<_Tp> == is_signed_v<_Up>)
    return __t < __u;
  else if constexpr (__comparison_can_promote_to<_Tp, int> && __comparison_can_promote_to<_Up, int>)
    return static_cast<int>(__t) < static_cast<int>(__u);
  else if constexpr (__comparison_can_promote_to<_Tp, long long> && __comparison_can_promote_to<_Up, long long>)
    return static_cast<long long>(__t) < static_cast<long long>(__u);
  else if constexpr (is_signed_v<_Tp>)
    return __t < 0 ? true : make_unsigned_t<_Tp>(__t) < __u;
  else
    return __u < 0 ? false : __t < make_unsigned_t<_Up>(__u);
}

template <__signed_or_unsigned_integer _Tp, __signed_or_unsigned_integer _Up>
[[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr bool cmp_greater(_Tp __t, _Up __u) noexcept {
  return std::cmp_less(__u, __t);
}

template <__signed_or_unsigned_integer _Tp, __signed_or_unsigned_integer _Up>
[[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr bool cmp_less_equal(_Tp __t, _Up __u) noexcept {
  return !std::cmp_greater(__t, __u);
}

template <__signed_or_unsigned_integer _Tp, __signed_or_unsigned_integer _Up>
[[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr bool cmp_greater_equal(_Tp __t, _Up __u) noexcept {
  return !std::cmp_less(__t, __u);
}

template <__signed_or_unsigned_integer _Tp, __signed_or_unsigned_integer _Up>
[[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr bool in_range(_Up __u) noexcept {
  return std::cmp_less_equal(__u, numeric_limits<_Tp>::max()) &&
         std::cmp_greater_equal(__u, numeric_limits<_Tp>::min());
}

_LIBCPP_END_NAMESPACE_STD

#endif // _LIBCPP_STD_VER >= 20

_LIBCPP_POP_MACROS

#endif // _LIBCPP___UTILITY_CMP_H