920 lines
27 KiB
C++
920 lines
27 KiB
C++
// -*- C++ -*- operator<=> three-way comparison support.
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// Copyright (C) 2019-2021 Free Software Foundation, Inc.
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//
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// This file is part of GCC.
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//
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// GCC is free software; you can redistribute it and/or modify
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// it under the terms of the GNU General Public License as published by
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// the Free Software Foundation; either version 3, or (at your option)
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// any later version.
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//
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// GCC is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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//
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// Under Section 7 of GPL version 3, you are granted additional
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// permissions described in the GCC Runtime Library Exception, version
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// 3.1, as published by the Free Software Foundation.
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// You should have received a copy of the GNU General Public License and
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// a copy of the GCC Runtime Library Exception along with this program;
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// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
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// <http://www.gnu.org/licenses/>.
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/** @file compare
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* This is a Standard C++ Library header.
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*/
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#ifndef _COMPARE
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#define _COMPARE
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#pragma GCC system_header
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#if __cplusplus > 201703L && __cpp_impl_three_way_comparison >= 201907L
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#pragma GCC visibility push(default)
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#include <concepts>
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#if __cpp_lib_concepts
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# define __cpp_lib_three_way_comparison 201907L
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#endif
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namespace std
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{
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// [cmp.categories], comparison category types
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namespace __cmp_cat
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{
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using type = signed char;
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enum class _Ord : type { equivalent = 0, less = -1, greater = 1 };
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enum class _Ncmp : type { _Unordered = 2 };
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struct __unspec
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{
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constexpr __unspec(__unspec*) noexcept { }
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};
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}
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class partial_ordering
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{
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// less=0xff, equiv=0x00, greater=0x01, unordered=0x02
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__cmp_cat::type _M_value;
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constexpr explicit
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partial_ordering(__cmp_cat::_Ord __v) noexcept
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: _M_value(__cmp_cat::type(__v))
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{ }
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constexpr explicit
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partial_ordering(__cmp_cat::_Ncmp __v) noexcept
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: _M_value(__cmp_cat::type(__v))
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{ }
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friend class weak_ordering;
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friend class strong_ordering;
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public:
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// valid values
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static const partial_ordering less;
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static const partial_ordering equivalent;
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static const partial_ordering greater;
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static const partial_ordering unordered;
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// comparisons
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friend constexpr bool
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operator==(partial_ordering __v, __cmp_cat::__unspec) noexcept
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{ return __v._M_value == 0; }
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friend constexpr bool
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operator==(partial_ordering, partial_ordering) noexcept = default;
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friend constexpr bool
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operator< (partial_ordering __v, __cmp_cat::__unspec) noexcept
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{ return __v._M_value == -1; }
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friend constexpr bool
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operator> (partial_ordering __v, __cmp_cat::__unspec) noexcept
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{ return __v._M_value == 1; }
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friend constexpr bool
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operator<=(partial_ordering __v, __cmp_cat::__unspec) noexcept
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{ return __v._M_value <= 0; }
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friend constexpr bool
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operator>=(partial_ordering __v, __cmp_cat::__unspec) noexcept
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{ return __cmp_cat::type(__v._M_value & 1) == __v._M_value; }
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friend constexpr bool
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operator< (__cmp_cat::__unspec, partial_ordering __v) noexcept
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{ return __v._M_value == 1; }
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friend constexpr bool
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operator> (__cmp_cat::__unspec, partial_ordering __v) noexcept
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{ return __v._M_value == -1; }
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friend constexpr bool
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operator<=(__cmp_cat::__unspec, partial_ordering __v) noexcept
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{ return __cmp_cat::type(__v._M_value & 1) == __v._M_value; }
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friend constexpr bool
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operator>=(__cmp_cat::__unspec, partial_ordering __v) noexcept
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{ return 0 >= __v._M_value; }
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friend constexpr partial_ordering
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operator<=>(partial_ordering __v, __cmp_cat::__unspec) noexcept
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{ return __v; }
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friend constexpr partial_ordering
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operator<=>(__cmp_cat::__unspec, partial_ordering __v) noexcept
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{
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if (__v._M_value & 1)
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return partial_ordering(__cmp_cat::_Ord(-__v._M_value));
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else
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return __v;
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}
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};
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// valid values' definitions
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inline constexpr partial_ordering
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partial_ordering::less(__cmp_cat::_Ord::less);
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inline constexpr partial_ordering
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partial_ordering::equivalent(__cmp_cat::_Ord::equivalent);
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inline constexpr partial_ordering
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partial_ordering::greater(__cmp_cat::_Ord::greater);
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inline constexpr partial_ordering
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partial_ordering::unordered(__cmp_cat::_Ncmp::_Unordered);
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class weak_ordering
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{
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__cmp_cat::type _M_value;
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constexpr explicit
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weak_ordering(__cmp_cat::_Ord __v) noexcept : _M_value(__cmp_cat::type(__v))
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{ }
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friend class strong_ordering;
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public:
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// valid values
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static const weak_ordering less;
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static const weak_ordering equivalent;
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static const weak_ordering greater;
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constexpr operator partial_ordering() const noexcept
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{ return partial_ordering(__cmp_cat::_Ord(_M_value)); }
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// comparisons
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friend constexpr bool
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operator==(weak_ordering __v, __cmp_cat::__unspec) noexcept
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{ return __v._M_value == 0; }
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friend constexpr bool
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operator==(weak_ordering, weak_ordering) noexcept = default;
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friend constexpr bool
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operator< (weak_ordering __v, __cmp_cat::__unspec) noexcept
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{ return __v._M_value < 0; }
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friend constexpr bool
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operator> (weak_ordering __v, __cmp_cat::__unspec) noexcept
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{ return __v._M_value > 0; }
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friend constexpr bool
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operator<=(weak_ordering __v, __cmp_cat::__unspec) noexcept
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{ return __v._M_value <= 0; }
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friend constexpr bool
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operator>=(weak_ordering __v, __cmp_cat::__unspec) noexcept
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{ return __v._M_value >= 0; }
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friend constexpr bool
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operator< (__cmp_cat::__unspec, weak_ordering __v) noexcept
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{ return 0 < __v._M_value; }
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friend constexpr bool
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operator> (__cmp_cat::__unspec, weak_ordering __v) noexcept
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{ return 0 > __v._M_value; }
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friend constexpr bool
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operator<=(__cmp_cat::__unspec, weak_ordering __v) noexcept
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{ return 0 <= __v._M_value; }
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friend constexpr bool
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operator>=(__cmp_cat::__unspec, weak_ordering __v) noexcept
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{ return 0 >= __v._M_value; }
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friend constexpr weak_ordering
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operator<=>(weak_ordering __v, __cmp_cat::__unspec) noexcept
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{ return __v; }
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friend constexpr weak_ordering
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operator<=>(__cmp_cat::__unspec, weak_ordering __v) noexcept
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{ return weak_ordering(__cmp_cat::_Ord(-__v._M_value)); }
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};
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// valid values' definitions
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inline constexpr weak_ordering
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weak_ordering::less(__cmp_cat::_Ord::less);
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inline constexpr weak_ordering
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weak_ordering::equivalent(__cmp_cat::_Ord::equivalent);
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inline constexpr weak_ordering
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weak_ordering::greater(__cmp_cat::_Ord::greater);
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class strong_ordering
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{
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__cmp_cat::type _M_value;
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constexpr explicit
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strong_ordering(__cmp_cat::_Ord __v) noexcept
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: _M_value(__cmp_cat::type(__v))
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{ }
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public:
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// valid values
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static const strong_ordering less;
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static const strong_ordering equal;
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static const strong_ordering equivalent;
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static const strong_ordering greater;
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constexpr operator partial_ordering() const noexcept
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{ return partial_ordering(__cmp_cat::_Ord(_M_value)); }
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constexpr operator weak_ordering() const noexcept
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{ return weak_ordering(__cmp_cat::_Ord(_M_value)); }
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// comparisons
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friend constexpr bool
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operator==(strong_ordering __v, __cmp_cat::__unspec) noexcept
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{ return __v._M_value == 0; }
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friend constexpr bool
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operator==(strong_ordering, strong_ordering) noexcept = default;
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friend constexpr bool
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operator< (strong_ordering __v, __cmp_cat::__unspec) noexcept
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{ return __v._M_value < 0; }
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friend constexpr bool
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operator> (strong_ordering __v, __cmp_cat::__unspec) noexcept
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{ return __v._M_value > 0; }
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friend constexpr bool
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operator<=(strong_ordering __v, __cmp_cat::__unspec) noexcept
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{ return __v._M_value <= 0; }
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friend constexpr bool
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operator>=(strong_ordering __v, __cmp_cat::__unspec) noexcept
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{ return __v._M_value >= 0; }
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friend constexpr bool
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operator< (__cmp_cat::__unspec, strong_ordering __v) noexcept
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{ return 0 < __v._M_value; }
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friend constexpr bool
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operator> (__cmp_cat::__unspec, strong_ordering __v) noexcept
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{ return 0 > __v._M_value; }
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friend constexpr bool
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operator<=(__cmp_cat::__unspec, strong_ordering __v) noexcept
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{ return 0 <= __v._M_value; }
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friend constexpr bool
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operator>=(__cmp_cat::__unspec, strong_ordering __v) noexcept
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{ return 0 >= __v._M_value; }
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friend constexpr strong_ordering
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operator<=>(strong_ordering __v, __cmp_cat::__unspec) noexcept
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{ return __v; }
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friend constexpr strong_ordering
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operator<=>(__cmp_cat::__unspec, strong_ordering __v) noexcept
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{ return strong_ordering(__cmp_cat::_Ord(-__v._M_value)); }
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};
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// valid values' definitions
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inline constexpr strong_ordering
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strong_ordering::less(__cmp_cat::_Ord::less);
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inline constexpr strong_ordering
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strong_ordering::equal(__cmp_cat::_Ord::equivalent);
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inline constexpr strong_ordering
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strong_ordering::equivalent(__cmp_cat::_Ord::equivalent);
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inline constexpr strong_ordering
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strong_ordering::greater(__cmp_cat::_Ord::greater);
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// named comparison functions
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constexpr bool
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is_eq(partial_ordering __cmp) noexcept
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{ return __cmp == 0; }
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constexpr bool
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is_neq(partial_ordering __cmp) noexcept
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{ return __cmp != 0; }
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constexpr bool
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is_lt (partial_ordering __cmp) noexcept
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{ return __cmp < 0; }
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constexpr bool
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is_lteq(partial_ordering __cmp) noexcept
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{ return __cmp <= 0; }
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constexpr bool
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is_gt (partial_ordering __cmp) noexcept
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{ return __cmp > 0; }
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constexpr bool
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is_gteq(partial_ordering __cmp) noexcept
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{ return __cmp >= 0; }
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namespace __detail
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{
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template<typename _Tp>
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inline constexpr unsigned __cmp_cat_id = 1;
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template<>
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inline constexpr unsigned __cmp_cat_id<partial_ordering> = 2;
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template<>
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inline constexpr unsigned __cmp_cat_id<weak_ordering> = 4;
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template<>
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inline constexpr unsigned __cmp_cat_id<strong_ordering> = 8;
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template<typename... _Ts>
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constexpr auto __common_cmp_cat()
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{
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constexpr unsigned __cats = (__cmp_cat_id<_Ts> | ...);
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// If any Ti is not a comparison category type, U is void.
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if constexpr (__cats & 1)
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return;
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// Otherwise, if at least one Ti is std::partial_ordering,
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// U is std::partial_ordering.
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else if constexpr (bool(__cats & __cmp_cat_id<partial_ordering>))
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return partial_ordering::equivalent;
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// Otherwise, if at least one Ti is std::weak_ordering,
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// U is std::weak_ordering.
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else if constexpr (bool(__cats & __cmp_cat_id<weak_ordering>))
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return weak_ordering::equivalent;
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// Otherwise, U is std::strong_ordering.
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else
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return strong_ordering::equivalent;
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}
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} // namespace __detail
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// [cmp.common], common comparison category type
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template<typename... _Ts>
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struct common_comparison_category
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{
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using type = decltype(__detail::__common_cmp_cat<_Ts...>());
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};
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// Partial specializations for one and zero argument cases.
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template<typename _Tp>
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struct common_comparison_category<_Tp>
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{ using type = void; };
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template<>
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struct common_comparison_category<partial_ordering>
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{ using type = partial_ordering; };
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template<>
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struct common_comparison_category<weak_ordering>
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{ using type = weak_ordering; };
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template<>
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struct common_comparison_category<strong_ordering>
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{ using type = strong_ordering; };
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template<>
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struct common_comparison_category<>
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{ using type = strong_ordering; };
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template<typename... _Ts>
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using common_comparison_category_t
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= typename common_comparison_category<_Ts...>::type;
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#if __cpp_lib_concepts
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namespace __detail
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{
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template<typename _Tp, typename _Cat>
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concept __compares_as
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= same_as<common_comparison_category_t<_Tp, _Cat>, _Cat>;
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} // namespace __detail
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// [cmp.concept], concept three_way_comparable
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template<typename _Tp, typename _Cat = partial_ordering>
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concept three_way_comparable
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= __detail::__weakly_eq_cmp_with<_Tp, _Tp>
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&& __detail::__partially_ordered_with<_Tp, _Tp>
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&& requires(const remove_reference_t<_Tp>& __a,
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const remove_reference_t<_Tp>& __b)
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{
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{ __a <=> __b } -> __detail::__compares_as<_Cat>;
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};
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template<typename _Tp, typename _Up, typename _Cat = partial_ordering>
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concept three_way_comparable_with
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= three_way_comparable<_Tp, _Cat>
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&& three_way_comparable<_Up, _Cat>
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&& common_reference_with<const remove_reference_t<_Tp>&,
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const remove_reference_t<_Up>&>
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&& three_way_comparable<
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common_reference_t<const remove_reference_t<_Tp>&,
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const remove_reference_t<_Up>&>, _Cat>
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&& __detail::__weakly_eq_cmp_with<_Tp, _Up>
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&& __detail::__partially_ordered_with<_Tp, _Up>
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&& requires(const remove_reference_t<_Tp>& __t,
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const remove_reference_t<_Up>& __u)
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{
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{ __t <=> __u } -> __detail::__compares_as<_Cat>;
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{ __u <=> __t } -> __detail::__compares_as<_Cat>;
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};
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namespace __detail
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{
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template<typename _Tp, typename _Up>
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using __cmp3way_res_t
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= decltype(std::declval<_Tp>() <=> std::declval<_Up>());
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// Implementation of std::compare_three_way_result.
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// It is undefined for a program to add specializations of
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// std::compare_three_way_result, so the std::compare_three_way_result_t
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// alias ignores std::compare_three_way_result and uses
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// __detail::__cmp3way_res_impl directly instead.
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template<typename _Tp, typename _Up>
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struct __cmp3way_res_impl
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{ };
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template<typename _Tp, typename _Up>
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requires requires { typename __cmp3way_res_t<__cref<_Tp>, __cref<_Up>>; }
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struct __cmp3way_res_impl<_Tp, _Up>
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{
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using type = __cmp3way_res_t<__cref<_Tp>, __cref<_Up>>;
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};
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} // namespace __detail
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/// [cmp.result], result of three-way comparison
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template<typename _Tp, typename _Up = _Tp>
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struct compare_three_way_result
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: __detail::__cmp3way_res_impl<_Tp, _Up>
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{ };
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/// [cmp.result], result of three-way comparison
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template<typename _Tp, typename _Up = _Tp>
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using compare_three_way_result_t
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= typename __detail::__cmp3way_res_impl<_Tp, _Up>::type;
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namespace __detail
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{
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// BUILTIN-PTR-THREE-WAY(T, U)
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template<typename _Tp, typename _Up>
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concept __3way_builtin_ptr_cmp
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= requires(_Tp&& __t, _Up&& __u)
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{ static_cast<_Tp&&>(__t) <=> static_cast<_Up&&>(__u); }
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&& convertible_to<_Tp, const volatile void*>
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&& convertible_to<_Up, const volatile void*>
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&& ! requires(_Tp&& __t, _Up&& __u)
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{ operator<=>(static_cast<_Tp&&>(__t), static_cast<_Up&&>(__u)); }
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&& ! requires(_Tp&& __t, _Up&& __u)
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{ static_cast<_Tp&&>(__t).operator<=>(static_cast<_Up&&>(__u)); };
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} // namespace __detail
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// [cmp.object], typename compare_three_way
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struct compare_three_way
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{
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template<typename _Tp, typename _Up>
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requires three_way_comparable_with<_Tp, _Up>
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|| __detail::__3way_builtin_ptr_cmp<_Tp, _Up>
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constexpr auto
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operator()(_Tp&& __t, _Up&& __u) const
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noexcept(noexcept(std::declval<_Tp>() <=> std::declval<_Up>()))
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{
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if constexpr (__detail::__3way_builtin_ptr_cmp<_Tp, _Up>)
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{
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auto __pt = static_cast<const volatile void*>(__t);
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auto __pu = static_cast<const volatile void*>(__u);
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if (__builtin_is_constant_evaluated())
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return __pt <=> __pu;
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auto __it = reinterpret_cast<__UINTPTR_TYPE__>(__pt);
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auto __iu = reinterpret_cast<__UINTPTR_TYPE__>(__pu);
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return __it <=> __iu;
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}
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else
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return static_cast<_Tp&&>(__t) <=> static_cast<_Up&&>(__u);
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}
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using is_transparent = void;
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};
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namespace __cmp_cust
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{
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template<floating_point _Tp>
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constexpr weak_ordering
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__fp_weak_ordering(_Tp __e, _Tp __f)
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{
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// Returns an integer with the same sign as the argument, and magnitude
|
|
// indicating the classification: zero=1 subnorm=2 norm=3 inf=4 nan=5
|
|
auto __cat = [](_Tp __fp) -> int {
|
|
const int __sign = __builtin_signbit(__fp) ? -1 : 1;
|
|
if (__builtin_isnormal(__fp))
|
|
return (__fp == 0 ? 1 : 3) * __sign;
|
|
if (__builtin_isnan(__fp))
|
|
return 5 * __sign;
|
|
if (int __inf = __builtin_isinf_sign(__fp))
|
|
return 4 * __inf;
|
|
return 2 * __sign;
|
|
};
|
|
|
|
auto __po = __e <=> __f;
|
|
if (is_lt(__po))
|
|
return weak_ordering::less;
|
|
else if (is_gt(__po))
|
|
return weak_ordering::greater;
|
|
else if (__po == partial_ordering::equivalent)
|
|
return weak_ordering::equivalent;
|
|
else // unordered, at least one argument is NaN
|
|
{
|
|
// return -1 for negative nan, +1 for positive nan, 0 otherwise.
|
|
auto __isnan_sign = [](_Tp __fp) -> int {
|
|
return __builtin_isnan(__fp)
|
|
? __builtin_signbit(__fp) ? -1 : 1
|
|
: 0;
|
|
};
|
|
auto __ord = __isnan_sign(__e) <=> __isnan_sign(__f);
|
|
if (is_eq(__ord))
|
|
return weak_ordering::equivalent;
|
|
else if (is_lt(__ord))
|
|
return weak_ordering::less;
|
|
else
|
|
return weak_ordering::greater;
|
|
}
|
|
}
|
|
|
|
template<typename _Tp, typename _Up>
|
|
concept __adl_strong = requires(_Tp&& __t, _Up&& __u)
|
|
{
|
|
strong_ordering(strong_order(static_cast<_Tp&&>(__t),
|
|
static_cast<_Up&&>(__u)));
|
|
};
|
|
|
|
template<typename _Tp, typename _Up>
|
|
concept __adl_weak = requires(_Tp&& __t, _Up&& __u)
|
|
{
|
|
weak_ordering(weak_order(static_cast<_Tp&&>(__t),
|
|
static_cast<_Up&&>(__u)));
|
|
};
|
|
|
|
template<typename _Tp, typename _Up>
|
|
concept __adl_partial = requires(_Tp&& __t, _Up&& __u)
|
|
{
|
|
partial_ordering(partial_order(static_cast<_Tp&&>(__t),
|
|
static_cast<_Up&&>(__u)));
|
|
};
|
|
|
|
template<typename _Ord, typename _Tp, typename _Up>
|
|
concept __cmp3way = requires(_Tp&& __t, _Up&& __u, compare_three_way __c)
|
|
{
|
|
_Ord(__c(static_cast<_Tp&&>(__t), static_cast<_Up&&>(__u)));
|
|
};
|
|
|
|
template<typename _Tp, typename _Up>
|
|
concept __strongly_ordered
|
|
= __adl_strong<_Tp, _Up>
|
|
// FIXME: || floating_point<remove_reference_t<_Tp>>
|
|
|| __cmp3way<strong_ordering, _Tp, _Up>;
|
|
|
|
class _Strong_order
|
|
{
|
|
template<typename _Tp, typename _Up>
|
|
static constexpr bool
|
|
_S_noexcept()
|
|
{
|
|
if constexpr (floating_point<decay_t<_Tp>>)
|
|
return true;
|
|
else if constexpr (__adl_strong<_Tp, _Up>)
|
|
return noexcept(strong_ordering(strong_order(std::declval<_Tp>(),
|
|
std::declval<_Up>())));
|
|
else if constexpr (__cmp3way<strong_ordering, _Tp, _Up>)
|
|
return noexcept(compare_three_way()(std::declval<_Tp>(),
|
|
std::declval<_Up>()));
|
|
}
|
|
|
|
friend class _Weak_order;
|
|
friend class _Strong_fallback;
|
|
|
|
public:
|
|
template<typename _Tp, typename _Up>
|
|
requires __strongly_ordered<_Tp, _Up>
|
|
constexpr strong_ordering
|
|
operator()(_Tp&& __e, _Up&& __f) const
|
|
noexcept(_S_noexcept<_Tp, _Up>())
|
|
{
|
|
static_assert(same_as<decay_t<_Tp>, decay_t<_Up>>);
|
|
|
|
/* FIXME:
|
|
if constexpr (floating_point<decay_t<_Tp>>)
|
|
return __cmp_cust::__fp_strong_order(__e, __f);
|
|
else */ if constexpr (__adl_strong<_Tp, _Up>)
|
|
return strong_ordering(strong_order(static_cast<_Tp&&>(__e),
|
|
static_cast<_Up&&>(__f)));
|
|
else if constexpr (__cmp3way<strong_ordering, _Tp, _Up>)
|
|
return compare_three_way()(static_cast<_Tp&&>(__e),
|
|
static_cast<_Up&&>(__f));
|
|
}
|
|
};
|
|
|
|
template<typename _Tp, typename _Up>
|
|
concept __weakly_ordered
|
|
= floating_point<remove_reference_t<_Tp>>
|
|
|| __adl_weak<_Tp, _Up>
|
|
|| __cmp3way<weak_ordering, _Tp, _Up>
|
|
|| __strongly_ordered<_Tp, _Up>;
|
|
|
|
class _Weak_order
|
|
{
|
|
template<typename _Tp, typename _Up>
|
|
static constexpr bool
|
|
_S_noexcept()
|
|
{
|
|
if constexpr (floating_point<decay_t<_Tp>>)
|
|
return true;
|
|
else if constexpr (__adl_weak<_Tp, _Up>)
|
|
return noexcept(weak_ordering(weak_order(std::declval<_Tp>(),
|
|
std::declval<_Up>())));
|
|
else if constexpr (__cmp3way<weak_ordering, _Tp, _Up>)
|
|
return noexcept(compare_three_way()(std::declval<_Tp>(),
|
|
std::declval<_Up>()));
|
|
else if constexpr (__strongly_ordered<_Tp, _Up>)
|
|
return _Strong_order::_S_noexcept<_Tp, _Up>();
|
|
}
|
|
|
|
friend class _Partial_order;
|
|
friend class _Weak_fallback;
|
|
|
|
public:
|
|
template<typename _Tp, typename _Up>
|
|
requires __weakly_ordered<_Tp, _Up>
|
|
constexpr weak_ordering
|
|
operator()(_Tp&& __e, _Up&& __f) const
|
|
noexcept(_S_noexcept<_Tp, _Up>())
|
|
{
|
|
static_assert(same_as<decay_t<_Tp>, decay_t<_Up>>);
|
|
|
|
if constexpr (floating_point<decay_t<_Tp>>)
|
|
return __cmp_cust::__fp_weak_ordering(__e, __f);
|
|
else if constexpr (__adl_weak<_Tp, _Up>)
|
|
return weak_ordering(weak_order(static_cast<_Tp&&>(__e),
|
|
static_cast<_Up&&>(__f)));
|
|
else if constexpr (__cmp3way<weak_ordering, _Tp, _Up>)
|
|
return compare_three_way()(static_cast<_Tp&&>(__e),
|
|
static_cast<_Up&&>(__f));
|
|
else if constexpr (__strongly_ordered<_Tp, _Up>)
|
|
return _Strong_order{}(static_cast<_Tp&&>(__e),
|
|
static_cast<_Up&&>(__f));
|
|
}
|
|
};
|
|
|
|
template<typename _Tp, typename _Up>
|
|
concept __partially_ordered
|
|
= __adl_partial<_Tp, _Up>
|
|
|| __cmp3way<partial_ordering, _Tp, _Up>
|
|
|| __weakly_ordered<_Tp, _Up>;
|
|
|
|
class _Partial_order
|
|
{
|
|
template<typename _Tp, typename _Up>
|
|
static constexpr bool
|
|
_S_noexcept()
|
|
{
|
|
if constexpr (__adl_partial<_Tp, _Up>)
|
|
return noexcept(partial_ordering(partial_order(std::declval<_Tp>(),
|
|
std::declval<_Up>())));
|
|
else if constexpr (__cmp3way<partial_ordering, _Tp, _Up>)
|
|
return noexcept(compare_three_way()(std::declval<_Tp>(),
|
|
std::declval<_Up>()));
|
|
else if constexpr (__weakly_ordered<_Tp, _Up>)
|
|
return _Weak_order::_S_noexcept<_Tp, _Up>();
|
|
}
|
|
|
|
friend class _Partial_fallback;
|
|
|
|
public:
|
|
template<typename _Tp, typename _Up>
|
|
requires __partially_ordered<_Tp, _Up>
|
|
constexpr partial_ordering
|
|
operator()(_Tp&& __e, _Up&& __f) const
|
|
noexcept(_S_noexcept<_Tp, _Up>())
|
|
{
|
|
static_assert(same_as<decay_t<_Tp>, decay_t<_Up>>);
|
|
|
|
if constexpr (__adl_partial<_Tp, _Up>)
|
|
return partial_ordering(partial_order(static_cast<_Tp&&>(__e),
|
|
static_cast<_Up&&>(__f)));
|
|
else if constexpr (__cmp3way<partial_ordering, _Tp, _Up>)
|
|
return compare_three_way()(static_cast<_Tp&&>(__e),
|
|
static_cast<_Up&&>(__f));
|
|
else if constexpr (__weakly_ordered<_Tp, _Up>)
|
|
return _Weak_order{}(static_cast<_Tp&&>(__e),
|
|
static_cast<_Up&&>(__f));
|
|
}
|
|
};
|
|
|
|
template<typename _Tp, typename _Up>
|
|
concept __op_eq_lt = requires(_Tp&& __t, _Up&& __u)
|
|
{
|
|
{ static_cast<_Tp&&>(__t) == static_cast<_Up&&>(__u) }
|
|
-> convertible_to<bool>;
|
|
{ static_cast<_Tp&&>(__t) < static_cast<_Up&&>(__u) }
|
|
-> convertible_to<bool>;
|
|
};
|
|
|
|
class _Strong_fallback
|
|
{
|
|
template<typename _Tp, typename _Up>
|
|
static constexpr bool
|
|
_S_noexcept()
|
|
{
|
|
if constexpr (__strongly_ordered<_Tp, _Up>)
|
|
return _Strong_order::_S_noexcept<_Tp, _Up>();
|
|
else
|
|
return noexcept(bool(std::declval<_Tp>() == std::declval<_Up>()))
|
|
&& noexcept(bool(std::declval<_Tp>() < std::declval<_Up>()));
|
|
}
|
|
|
|
public:
|
|
template<typename _Tp, typename _Up>
|
|
requires __strongly_ordered<_Tp, _Up> || __op_eq_lt<_Tp, _Up>
|
|
constexpr decltype(auto)
|
|
operator()(_Tp&& __e, _Up&& __f) const
|
|
noexcept(_S_noexcept<_Tp, _Up>())
|
|
{
|
|
static_assert(same_as<decay_t<_Tp>, decay_t<_Up>>);
|
|
|
|
if constexpr (__strongly_ordered<_Tp, _Up>)
|
|
return _Strong_order{}(static_cast<_Tp&&>(__e),
|
|
static_cast<_Up&&>(__f));
|
|
else if constexpr (__op_eq_lt<_Tp, _Up>)
|
|
return static_cast<_Tp&&>(__e) == static_cast<_Up&&>(__f)
|
|
? strong_ordering::equal
|
|
: static_cast<_Tp&&>(__e) < static_cast<_Up&&>(__f)
|
|
? strong_ordering::less
|
|
: strong_ordering::greater;
|
|
}
|
|
};
|
|
|
|
class _Weak_fallback
|
|
{
|
|
template<typename _Tp, typename _Up>
|
|
static constexpr bool
|
|
_S_noexcept()
|
|
{
|
|
if constexpr (__weakly_ordered<_Tp, _Up>)
|
|
return _Weak_order::_S_noexcept<_Tp, _Up>();
|
|
else
|
|
return noexcept(bool(std::declval<_Tp>() == std::declval<_Up>()))
|
|
&& noexcept(bool(std::declval<_Tp>() < std::declval<_Up>()));
|
|
}
|
|
|
|
public:
|
|
template<typename _Tp, typename _Up>
|
|
requires __weakly_ordered<_Tp, _Up> || __op_eq_lt<_Tp, _Up>
|
|
constexpr decltype(auto)
|
|
operator()(_Tp&& __e, _Up&& __f) const
|
|
noexcept(_S_noexcept<_Tp, _Up>())
|
|
{
|
|
static_assert(same_as<decay_t<_Tp>, decay_t<_Up>>);
|
|
|
|
if constexpr (__weakly_ordered<_Tp, _Up>)
|
|
return _Weak_order{}(static_cast<_Tp&&>(__e),
|
|
static_cast<_Up&&>(__f));
|
|
else if constexpr (__op_eq_lt<_Tp, _Up>)
|
|
return static_cast<_Tp&&>(__e) == static_cast<_Up&&>(__f)
|
|
? weak_ordering::equivalent
|
|
: static_cast<_Tp&&>(__e) < static_cast<_Up&&>(__f)
|
|
? weak_ordering::less
|
|
: weak_ordering::greater;
|
|
}
|
|
};
|
|
|
|
class _Partial_fallback
|
|
{
|
|
template<typename _Tp, typename _Up>
|
|
static constexpr bool
|
|
_S_noexcept()
|
|
{
|
|
if constexpr (__partially_ordered<_Tp, _Up>)
|
|
return _Partial_order::_S_noexcept<_Tp, _Up>();
|
|
else
|
|
return noexcept(bool(std::declval<_Tp>() == std::declval<_Up>()))
|
|
&& noexcept(bool(std::declval<_Tp>() < std::declval<_Up>()));
|
|
}
|
|
|
|
public:
|
|
template<typename _Tp, typename _Up>
|
|
requires __partially_ordered<_Tp, _Up> || __op_eq_lt<_Tp, _Up>
|
|
constexpr decltype(auto)
|
|
operator()(_Tp&& __e, _Up&& __f) const
|
|
noexcept(_S_noexcept<_Tp, _Up>())
|
|
{
|
|
static_assert(same_as<decay_t<_Tp>, decay_t<_Up>>);
|
|
|
|
if constexpr (__partially_ordered<_Tp, _Up>)
|
|
return _Partial_order{}(static_cast<_Tp&&>(__e),
|
|
static_cast<_Up&&>(__f));
|
|
else if constexpr (__op_eq_lt<_Tp, _Up>)
|
|
return static_cast<_Tp&&>(__e) == static_cast<_Up&&>(__f)
|
|
? partial_ordering::equivalent
|
|
: static_cast<_Tp&&>(__e) < static_cast<_Up&&>(__f)
|
|
? partial_ordering::less
|
|
: static_cast<_Up&&>(__f) < static_cast<_Tp&&>(__e)
|
|
? partial_ordering::greater
|
|
: partial_ordering::unordered;
|
|
}
|
|
};
|
|
} // namespace __cmp_cust
|
|
|
|
// [cmp.alg], comparison algorithms
|
|
inline namespace __cmp_alg
|
|
{
|
|
inline constexpr __cmp_cust::_Strong_order strong_order{};
|
|
|
|
inline constexpr __cmp_cust::_Weak_order weak_order{};
|
|
|
|
inline constexpr __cmp_cust::_Partial_order partial_order{};
|
|
|
|
inline constexpr __cmp_cust::_Strong_fallback
|
|
compare_strong_order_fallback{};
|
|
|
|
inline constexpr __cmp_cust::_Weak_fallback
|
|
compare_weak_order_fallback{};
|
|
|
|
inline constexpr __cmp_cust::_Partial_fallback
|
|
compare_partial_order_fallback{};
|
|
}
|
|
|
|
namespace __detail
|
|
{
|
|
// [expos.only.func] synth-three-way
|
|
inline constexpr struct _Synth3way
|
|
{
|
|
template<typename _Tp, typename _Up>
|
|
static constexpr bool
|
|
_S_noexcept(const _Tp* __t = nullptr, const _Up* __u = nullptr)
|
|
{
|
|
if constexpr (three_way_comparable_with<_Tp, _Up>)
|
|
return noexcept(*__t <=> *__u);
|
|
else
|
|
return noexcept(*__t < *__u) && noexcept(*__u < *__t);
|
|
}
|
|
|
|
template<typename _Tp, typename _Up>
|
|
constexpr auto
|
|
operator()(const _Tp& __t, const _Up& __u) const
|
|
noexcept(_S_noexcept<_Tp, _Up>())
|
|
requires requires
|
|
{
|
|
{ __t < __u } -> __boolean_testable;
|
|
{ __u < __t } -> __boolean_testable;
|
|
}
|
|
{
|
|
if constexpr (three_way_comparable_with<_Tp, _Up>)
|
|
return __t <=> __u;
|
|
else
|
|
{
|
|
if (__t < __u)
|
|
return weak_ordering::less;
|
|
else if (__u < __t)
|
|
return weak_ordering::greater;
|
|
else
|
|
return weak_ordering::equivalent;
|
|
}
|
|
}
|
|
} __synth3way = {};
|
|
|
|
// [expos.only.func] synth-three-way-result
|
|
template<typename _Tp, typename _Up = _Tp>
|
|
using __synth3way_t
|
|
= decltype(__detail::__synth3way(std::declval<_Tp&>(),
|
|
std::declval<_Up&>()));
|
|
} // namespace __detail
|
|
#endif // concepts
|
|
} // namespace std
|
|
|
|
#pragma GCC visibility pop
|
|
|
|
#endif // C++20
|
|
|
|
#endif // _COMPARE
|