intcmp.h

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// Integer comparison functions -*- C++ -*-
 
// Copyright (C) 2020-2025 Free Software Foundation, Inc.
//
// This file is part of the GNU ISO C++ Library.  This library 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, or (at your option)
// any later version.
 
// This library 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.
 
// Under Section 7 of GPL version 3, you are granted additional
// permissions described in the GCC Runtime Library Exception, version
// 3.1, as published by the Free Software Foundation.
 
// You should have received a copy of the GNU General Public License and
// a copy of the GCC Runtime Library Exception along with this program;
// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
// <http://www.gnu.org/licenses/>.
 
/** @file bits/intcmp.h
 *  This is an internal header file, included by other library headers.
 *  Do not attempt to use it directly. @headername{utility}
 */
 
#ifndef _GLIBCXX_INTCMP_H
#define _GLIBCXX_INTCMP_H 1
 
#ifdef _GLIBCXX_SYSHDR
#pragma GCC system_header
#endif
 
#include <bits/version.h>
 
#ifdef __glibcxx_integer_comparison_functions // C++ >= 20
 
#include <type_traits>
#include <ext/numeric_traits.h> // __int_traits
 
namespace std _GLIBCXX_VISIBILITY(default)
{
_GLIBCXX_BEGIN_NAMESPACE_VERSION
 
  template<typename _Tp, typename _Up>
    constexpr bool
    cmp_equal(_Tp __t, _Up __u) noexcept
    {
      static_assert(__is_signed_or_unsigned_integer<_Tp>::value);
      static_assert(__is_signed_or_unsigned_integer<_Up>::value);
 
      if constexpr (is_signed_v<_Tp> == is_signed_v<_Up>)
        return __t == __u;
      else if constexpr (is_signed_v<_Tp>)
        return __t >= 0 && make_unsigned_t<_Tp>(__t) == __u;
      else
        return __u >= 0 && __t == make_unsigned_t<_Up>(__u);
    }
 
  template<typename _Tp, typename _Up>
    constexpr bool
    cmp_not_equal(_Tp __t, _Up __u) noexcept
    { return !std::cmp_equal(__t, __u); }
 
  template<typename _Tp, typename _Up>
    constexpr bool
    cmp_less(_Tp __t, _Up __u) noexcept
    {
      static_assert(__is_signed_or_unsigned_integer<_Tp>::value);
      static_assert(__is_signed_or_unsigned_integer<_Up>::value);
 
      if constexpr (is_signed_v<_Tp> == is_signed_v<_Up>)
        return __t < __u;
      else if constexpr (is_signed_v<_Tp>)
        return __t < 0 || make_unsigned_t<_Tp>(__t) < __u;
      else
        return __u >= 0 && __t < make_unsigned_t<_Up>(__u);
    }
 
  template<typename _Tp, typename _Up>
    constexpr bool
    cmp_greater(_Tp __t, _Up __u) noexcept
    { return std::cmp_less(__u, __t); }
 
  template<typename _Tp, typename _Up>
    constexpr bool
    cmp_less_equal(_Tp __t, _Up __u) noexcept
    { return !std::cmp_less(__u, __t); }
 
  template<typename _Tp, typename _Up>
    constexpr bool
    cmp_greater_equal(_Tp __t, _Up __u) noexcept
    { return !std::cmp_less(__t, __u); }
 
  template<typename _Res, typename _Tp>
    constexpr bool
    in_range(_Tp __t) noexcept
    {
      static_assert(__is_signed_or_unsigned_integer<_Res>::value);
      static_assert(__is_signed_or_unsigned_integer<_Tp>::value);
      using __gnu_cxx::__int_traits;
 
      if constexpr (is_signed_v<_Tp> == is_signed_v<_Res>)
        return __int_traits<_Res>::__min <= __t
          && __t <= __int_traits<_Res>::__max;
      else if constexpr (is_signed_v<_Tp>)
        return __t >= 0
          && make_unsigned_t<_Tp>(__t) <= __int_traits<_Res>::__max;
      else
        return __t <= make_unsigned_t<_Res>(__int_traits<_Res>::__max);
    }
 
_GLIBCXX_END_NAMESPACE_VERSION
} // namespace
 
#endif // __glibcxx_integer_comparison_functions
#endif // _GLIBCXX_INTCMP_H