527 lines
18 KiB
C++
527 lines
18 KiB
C++
// Pair implementation -*- C++ -*-
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// Copyright (C) 2001-2017 Free Software Foundation, Inc.
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//
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// This file is part of the GNU ISO C++ Library. This library is free
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// software; you can redistribute it and/or modify it under the
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// terms of the GNU General Public License as published by the
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// Free Software Foundation; either version 3, or (at your option)
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// any later version.
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// This library 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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// 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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/*
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*
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* Copyright (c) 1994
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* Hewlett-Packard Company
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*
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* Permission to use, copy, modify, distribute and sell this software
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* and its documentation for any purpose is hereby granted without fee,
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* provided that the above copyright notice appear in all copies and
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* that both that copyright notice and this permission notice appear
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* in supporting documentation. Hewlett-Packard Company makes no
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* representations about the suitability of this software for any
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* purpose. It is provided "as is" without express or implied warranty.
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*
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*
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* Copyright (c) 1996,1997
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* Silicon Graphics Computer Systems, Inc.
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*
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* Permission to use, copy, modify, distribute and sell this software
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* and its documentation for any purpose is hereby granted without fee,
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* provided that the above copyright notice appear in all copies and
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* that both that copyright notice and this permission notice appear
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* in supporting documentation. Silicon Graphics makes no
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* representations about the suitability of this software for any
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* purpose. It is provided "as is" without express or implied warranty.
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*/
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/** @file bits/stl_pair.h
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* This is an internal header file, included by other library headers.
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* Do not attempt to use it directly. @headername{utility}
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*/
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#ifndef _STL_PAIR_H
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#define _STL_PAIR_H 1
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#include <bits/move.h> // for std::move / std::forward, and std::swap
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#if __cplusplus >= 201103L
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#include <type_traits> // for std::__decay_and_strip too
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#endif
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namespace std _GLIBCXX_VISIBILITY(default)
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{
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_GLIBCXX_BEGIN_NAMESPACE_VERSION
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/**
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* @addtogroup utilities
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* @{
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*/
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#if __cplusplus >= 201103L
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/// piecewise_construct_t
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struct piecewise_construct_t { explicit piecewise_construct_t() = default; };
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/// piecewise_construct
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constexpr piecewise_construct_t piecewise_construct = piecewise_construct_t();
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// Forward declarations.
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template<typename...>
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class tuple;
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template<std::size_t...>
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struct _Index_tuple;
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// Concept utility functions, reused in conditionally-explicit
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// constructors.
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// See PR 70437, don't look at is_constructible or
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// is_convertible if the types are the same to
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// avoid querying those properties for incomplete types.
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template <bool, typename _T1, typename _T2>
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struct _PCC
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{
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template <typename _U1, typename _U2>
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static constexpr bool _ConstructiblePair()
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{
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return __and_<is_constructible<_T1, const _U1&>,
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is_constructible<_T2, const _U2&>>::value;
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}
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template <typename _U1, typename _U2>
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static constexpr bool _ImplicitlyConvertiblePair()
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{
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return __and_<is_convertible<const _U1&, _T1>,
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is_convertible<const _U2&, _T2>>::value;
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}
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template <typename _U1, typename _U2>
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static constexpr bool _MoveConstructiblePair()
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{
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return __and_<is_constructible<_T1, _U1&&>,
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is_constructible<_T2, _U2&&>>::value;
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}
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template <typename _U1, typename _U2>
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static constexpr bool _ImplicitlyMoveConvertiblePair()
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{
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return __and_<is_convertible<_U1&&, _T1>,
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is_convertible<_U2&&, _T2>>::value;
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}
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template <bool __implicit, typename _U1, typename _U2>
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static constexpr bool _CopyMovePair()
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{
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using __do_converts = __and_<is_convertible<const _U1&, _T1>,
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is_convertible<_U2&&, _T2>>;
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using __converts = typename conditional<__implicit,
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__do_converts,
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__not_<__do_converts>>::type;
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return __and_<is_constructible<_T1, const _U1&>,
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is_constructible<_T2, _U2&&>,
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__converts
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>::value;
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}
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template <bool __implicit, typename _U1, typename _U2>
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static constexpr bool _MoveCopyPair()
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{
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using __do_converts = __and_<is_convertible<_U1&&, _T1>,
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is_convertible<const _U2&, _T2>>;
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using __converts = typename conditional<__implicit,
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__do_converts,
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__not_<__do_converts>>::type;
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return __and_<is_constructible<_T1, _U1&&>,
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is_constructible<_T2, const _U2&&>,
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__converts
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>::value;
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}
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};
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template <typename _T1, typename _T2>
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struct _PCC<false, _T1, _T2>
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{
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template <typename _U1, typename _U2>
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static constexpr bool _ConstructiblePair()
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{
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return false;
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}
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template <typename _U1, typename _U2>
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static constexpr bool _ImplicitlyConvertiblePair()
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{
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return false;
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}
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template <typename _U1, typename _U2>
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static constexpr bool _MoveConstructiblePair()
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{
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return false;
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}
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template <typename _U1, typename _U2>
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static constexpr bool _ImplicitlyMoveConvertiblePair()
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{
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return false;
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}
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};
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#endif
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/**
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* @brief Struct holding two objects of arbitrary type.
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*
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* @tparam _T1 Type of first object.
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* @tparam _T2 Type of second object.
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*/
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template<typename _T1, typename _T2>
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struct pair
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{
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typedef _T1 first_type; /// @c first_type is the first bound type
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typedef _T2 second_type; /// @c second_type is the second bound type
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_T1 first; /// @c first is a copy of the first object
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_T2 second; /// @c second is a copy of the second object
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// _GLIBCXX_RESOLVE_LIB_DEFECTS
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// 265. std::pair::pair() effects overly restrictive
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/** The default constructor creates @c first and @c second using their
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* respective default constructors. */
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#if __cplusplus >= 201103L
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template <typename _U1 = _T1,
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typename _U2 = _T2,
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typename enable_if<__and_<
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__is_implicitly_default_constructible<_U1>,
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__is_implicitly_default_constructible<_U2>>
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::value, bool>::type = true>
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#endif
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_GLIBCXX_CONSTEXPR pair()
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: first(), second() { }
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#if __cplusplus >= 201103L
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template <typename _U1 = _T1,
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typename _U2 = _T2,
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typename enable_if<__and_<
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is_default_constructible<_U1>,
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is_default_constructible<_U2>,
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__not_<
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__and_<__is_implicitly_default_constructible<_U1>,
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__is_implicitly_default_constructible<_U2>>>>
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::value, bool>::type = false>
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explicit constexpr pair()
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: first(), second() { }
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#endif
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/** Two objects may be passed to a @c pair constructor to be copied. */
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#if __cplusplus < 201103L
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pair(const _T1& __a, const _T2& __b)
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: first(__a), second(__b) { }
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#else
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// Shortcut for constraining the templates that don't take pairs.
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using _PCCP = _PCC<true, _T1, _T2>;
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template<typename _U1 = _T1, typename _U2=_T2, typename
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enable_if<_PCCP::template
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_ConstructiblePair<_U1, _U2>()
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&& _PCCP::template
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_ImplicitlyConvertiblePair<_U1, _U2>(),
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bool>::type=true>
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constexpr pair(const _T1& __a, const _T2& __b)
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: first(__a), second(__b) { }
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template<typename _U1 = _T1, typename _U2=_T2, typename
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enable_if<_PCCP::template
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_ConstructiblePair<_U1, _U2>()
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&& !_PCCP::template
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_ImplicitlyConvertiblePair<_U1, _U2>(),
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bool>::type=false>
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explicit constexpr pair(const _T1& __a, const _T2& __b)
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: first(__a), second(__b) { }
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#endif
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/** There is also a templated copy ctor for the @c pair class itself. */
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#if __cplusplus < 201103L
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template<typename _U1, typename _U2>
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pair(const pair<_U1, _U2>& __p)
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: first(__p.first), second(__p.second) { }
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#else
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// Shortcut for constraining the templates that take pairs.
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template <typename _U1, typename _U2>
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using _PCCFP = _PCC<!is_same<_T1, _U1>::value
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|| !is_same<_T2, _U2>::value,
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_T1, _T2>;
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template<typename _U1, typename _U2, typename
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enable_if<_PCCFP<_U1, _U2>::template
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_ConstructiblePair<_U1, _U2>()
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&& _PCCFP<_U1, _U2>::template
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_ImplicitlyConvertiblePair<_U1, _U2>(),
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bool>::type=true>
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constexpr pair(const pair<_U1, _U2>& __p)
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: first(__p.first), second(__p.second) { }
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template<typename _U1, typename _U2, typename
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enable_if<_PCCFP<_U1, _U2>::template
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_ConstructiblePair<_U1, _U2>()
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&& !_PCCFP<_U1, _U2>::template
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_ImplicitlyConvertiblePair<_U1, _U2>(),
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bool>::type=false>
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explicit constexpr pair(const pair<_U1, _U2>& __p)
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: first(__p.first), second(__p.second) { }
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constexpr pair(const pair&) = default;
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constexpr pair(pair&&) = default;
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// DR 811.
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template<typename _U1, typename
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enable_if<_PCCP::template
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_MoveCopyPair<true, _U1, _T2>(),
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bool>::type=true>
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constexpr pair(_U1&& __x, const _T2& __y)
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: first(std::forward<_U1>(__x)), second(__y) { }
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template<typename _U1, typename
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enable_if<_PCCP::template
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_MoveCopyPair<false, _U1, _T2>(),
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bool>::type=false>
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explicit constexpr pair(_U1&& __x, const _T2& __y)
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: first(std::forward<_U1>(__x)), second(__y) { }
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template<typename _U2, typename
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enable_if<_PCCP::template
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_CopyMovePair<true, _T1, _U2>(),
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bool>::type=true>
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constexpr pair(const _T1& __x, _U2&& __y)
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: first(__x), second(std::forward<_U2>(__y)) { }
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template<typename _U2, typename
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enable_if<_PCCP::template
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_CopyMovePair<false, _T1, _U2>(),
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bool>::type=false>
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explicit pair(const _T1& __x, _U2&& __y)
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: first(__x), second(std::forward<_U2>(__y)) { }
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template<typename _U1, typename _U2, typename
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enable_if<_PCCP::template
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_MoveConstructiblePair<_U1, _U2>()
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&& _PCCP::template
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_ImplicitlyMoveConvertiblePair<_U1, _U2>(),
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bool>::type=true>
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constexpr pair(_U1&& __x, _U2&& __y)
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: first(std::forward<_U1>(__x)), second(std::forward<_U2>(__y)) { }
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template<typename _U1, typename _U2, typename
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enable_if<_PCCP::template
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_MoveConstructiblePair<_U1, _U2>()
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&& !_PCCP::template
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_ImplicitlyMoveConvertiblePair<_U1, _U2>(),
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bool>::type=false>
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explicit constexpr pair(_U1&& __x, _U2&& __y)
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: first(std::forward<_U1>(__x)), second(std::forward<_U2>(__y)) { }
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template<typename _U1, typename _U2, typename
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enable_if<_PCCFP<_U1, _U2>::template
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_MoveConstructiblePair<_U1, _U2>()
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&& _PCCFP<_U1, _U2>::template
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_ImplicitlyMoveConvertiblePair<_U1, _U2>(),
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bool>::type=true>
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constexpr pair(pair<_U1, _U2>&& __p)
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: first(std::forward<_U1>(__p.first)),
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second(std::forward<_U2>(__p.second)) { }
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template<typename _U1, typename _U2, typename
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enable_if<_PCCFP<_U1, _U2>::template
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_MoveConstructiblePair<_U1, _U2>()
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&& !_PCCFP<_U1, _U2>::template
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_ImplicitlyMoveConvertiblePair<_U1, _U2>(),
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bool>::type=false>
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explicit constexpr pair(pair<_U1, _U2>&& __p)
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: first(std::forward<_U1>(__p.first)),
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second(std::forward<_U2>(__p.second)) { }
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template<typename... _Args1, typename... _Args2>
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pair(piecewise_construct_t, tuple<_Args1...>, tuple<_Args2...>);
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pair&
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operator=(typename conditional<
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__and_<is_copy_assignable<_T1>,
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is_copy_assignable<_T2>>::value,
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const pair&, const __nonesuch&>::type __p)
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{
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first = __p.first;
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second = __p.second;
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return *this;
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}
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pair&
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operator=(typename conditional<
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__not_<__and_<is_copy_assignable<_T1>,
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is_copy_assignable<_T2>>>::value,
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const pair&, const __nonesuch&>::type __p) = delete;
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pair&
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operator=(typename conditional<
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__and_<is_move_assignable<_T1>,
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is_move_assignable<_T2>>::value,
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pair&&, __nonesuch&&>::type __p)
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noexcept(__and_<is_nothrow_move_assignable<_T1>,
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is_nothrow_move_assignable<_T2>>::value)
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{
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first = std::forward<first_type>(__p.first);
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second = std::forward<second_type>(__p.second);
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return *this;
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}
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template<typename _U1, typename _U2>
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typename enable_if<__and_<is_assignable<_T1&, const _U1&>,
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is_assignable<_T2&, const _U2&>>::value,
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pair&>::type
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operator=(const pair<_U1, _U2>& __p)
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{
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first = __p.first;
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second = __p.second;
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return *this;
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}
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template<typename _U1, typename _U2>
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typename enable_if<__and_<is_assignable<_T1&, _U1&&>,
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is_assignable<_T2&, _U2&&>>::value,
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pair&>::type
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operator=(pair<_U1, _U2>&& __p)
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{
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first = std::forward<_U1>(__p.first);
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second = std::forward<_U2>(__p.second);
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return *this;
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}
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void
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swap(pair& __p)
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noexcept(__and_<__is_nothrow_swappable<_T1>,
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__is_nothrow_swappable<_T2>>::value)
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{
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using std::swap;
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swap(first, __p.first);
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swap(second, __p.second);
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}
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private:
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template<typename... _Args1, std::size_t... _Indexes1,
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typename... _Args2, std::size_t... _Indexes2>
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pair(tuple<_Args1...>&, tuple<_Args2...>&,
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_Index_tuple<_Indexes1...>, _Index_tuple<_Indexes2...>);
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#endif
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};
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/// Two pairs of the same type are equal iff their members are equal.
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template<typename _T1, typename _T2>
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inline _GLIBCXX_CONSTEXPR bool
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operator==(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y)
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{ return __x.first == __y.first && __x.second == __y.second; }
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/// <http://gcc.gnu.org/onlinedocs/libstdc++/manual/utilities.html>
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template<typename _T1, typename _T2>
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inline _GLIBCXX_CONSTEXPR bool
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operator<(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y)
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{ return __x.first < __y.first
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|| (!(__y.first < __x.first) && __x.second < __y.second); }
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/// Uses @c operator== to find the result.
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template<typename _T1, typename _T2>
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inline _GLIBCXX_CONSTEXPR bool
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operator!=(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y)
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{ return !(__x == __y); }
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/// Uses @c operator< to find the result.
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template<typename _T1, typename _T2>
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inline _GLIBCXX_CONSTEXPR bool
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operator>(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y)
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{ return __y < __x; }
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/// Uses @c operator< to find the result.
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template<typename _T1, typename _T2>
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inline _GLIBCXX_CONSTEXPR bool
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operator<=(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y)
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{ return !(__y < __x); }
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/// Uses @c operator< to find the result.
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template<typename _T1, typename _T2>
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inline _GLIBCXX_CONSTEXPR bool
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operator>=(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y)
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{ return !(__x < __y); }
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#if __cplusplus >= 201103L
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/// See std::pair::swap().
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// Note: no std::swap overloads in C++03 mode, this has performance
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// implications, see, eg, libstdc++/38466.
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template<typename _T1, typename _T2>
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inline
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#if __cplusplus > 201402L || !defined(__STRICT_ANSI__) // c++1z or gnu++11
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// Constrained free swap overload, see p0185r1
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typename enable_if<__and_<__is_swappable<_T1>,
|
|
__is_swappable<_T2>>::value>::type
|
|
#else
|
|
void
|
|
#endif
|
|
swap(pair<_T1, _T2>& __x, pair<_T1, _T2>& __y)
|
|
noexcept(noexcept(__x.swap(__y)))
|
|
{ __x.swap(__y); }
|
|
|
|
#if __cplusplus > 201402L || !defined(__STRICT_ANSI__) // c++1z or gnu++11
|
|
template<typename _T1, typename _T2>
|
|
typename enable_if<!__and_<__is_swappable<_T1>,
|
|
__is_swappable<_T2>>::value>::type
|
|
swap(pair<_T1, _T2>&, pair<_T1, _T2>&) = delete;
|
|
#endif
|
|
#endif // __cplusplus >= 201103L
|
|
|
|
/**
|
|
* @brief A convenience wrapper for creating a pair from two objects.
|
|
* @param __x The first object.
|
|
* @param __y The second object.
|
|
* @return A newly-constructed pair<> object of the appropriate type.
|
|
*
|
|
* The standard requires that the objects be passed by reference-to-const,
|
|
* but LWG issue #181 says they should be passed by const value. We follow
|
|
* the LWG by default.
|
|
*/
|
|
// _GLIBCXX_RESOLVE_LIB_DEFECTS
|
|
// 181. make_pair() unintended behavior
|
|
#if __cplusplus >= 201103L
|
|
// NB: DR 706.
|
|
template<typename _T1, typename _T2>
|
|
constexpr pair<typename __decay_and_strip<_T1>::__type,
|
|
typename __decay_and_strip<_T2>::__type>
|
|
make_pair(_T1&& __x, _T2&& __y)
|
|
{
|
|
typedef typename __decay_and_strip<_T1>::__type __ds_type1;
|
|
typedef typename __decay_and_strip<_T2>::__type __ds_type2;
|
|
typedef pair<__ds_type1, __ds_type2> __pair_type;
|
|
return __pair_type(std::forward<_T1>(__x), std::forward<_T2>(__y));
|
|
}
|
|
#else
|
|
template<typename _T1, typename _T2>
|
|
inline pair<_T1, _T2>
|
|
make_pair(_T1 __x, _T2 __y)
|
|
{ return pair<_T1, _T2>(__x, __y); }
|
|
#endif
|
|
|
|
/// @}
|
|
|
|
_GLIBCXX_END_NAMESPACE_VERSION
|
|
} // namespace std
|
|
|
|
#endif /* _STL_PAIR_H */
|