296 lines
9.6 KiB
C++
296 lines
9.6 KiB
C++
// Pair implementation -*- C++ -*-
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// Copyright (C) 2001-2015 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 { };
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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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#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<class _T1, class _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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_GLIBCXX_CONSTEXPR pair()
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: first(), second() { }
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/** Two objects may be passed to a @c pair constructor to be copied. */
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_GLIBCXX_CONSTEXPR pair(const _T1& __a, const _T2& __b)
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: first(__a), second(__b) { }
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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<class _U1, class _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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template<class _U1, class _U2, class = typename
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enable_if<__and_<is_convertible<const _U1&, _T1>,
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is_convertible<const _U2&, _T2>>::value>::type>
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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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constexpr pair(const pair&) = default;
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constexpr pair(pair&&) = default;
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// DR 811.
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template<class _U1, class = typename
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enable_if<is_convertible<_U1, _T1>::value>::type>
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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<class _U2, class = typename
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enable_if<is_convertible<_U2, _T2>::value>::type>
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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<class _U1, class _U2, class = typename
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enable_if<__and_<is_convertible<_U1, _T1>,
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is_convertible<_U2, _T2>>::value>::type>
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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<class _U1, class _U2, class = typename
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enable_if<__and_<is_convertible<_U1, _T1>,
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is_convertible<_U2, _T2>>::value>::type>
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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... _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=(const pair& __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=(pair&& __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<class _U1, class _U2>
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pair&
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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<class _U1, class _U2>
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pair&
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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(noexcept(swap(first, __p.first))
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&& noexcept(swap(second, __p.second)))
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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<class _T1, class _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<class _T1, class _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<class _T1, class _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<class _T1, class _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<class _T1, class _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<class _T1, class _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<class _T1, class _T2>
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inline void
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swap(pair<_T1, _T2>& __x, pair<_T1, _T2>& __y)
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noexcept(noexcept(__x.swap(__y)))
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{ __x.swap(__y); }
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#endif
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/**
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* @brief A convenience wrapper for creating a pair from two objects.
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* @param __x The first object.
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* @param __y The second object.
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* @return A newly-constructed pair<> object of the appropriate type.
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*
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* The standard requires that the objects be passed by reference-to-const,
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* but LWG issue #181 says they should be passed by const value. We follow
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* the LWG by default.
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*/
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// _GLIBCXX_RESOLVE_LIB_DEFECTS
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// 181. make_pair() unintended behavior
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#if __cplusplus >= 201103L
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// NB: DR 706.
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template<class _T1, class _T2>
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constexpr pair<typename __decay_and_strip<_T1>::__type,
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typename __decay_and_strip<_T2>::__type>
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make_pair(_T1&& __x, _T2&& __y)
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{
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typedef typename __decay_and_strip<_T1>::__type __ds_type1;
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typedef typename __decay_and_strip<_T2>::__type __ds_type2;
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typedef pair<__ds_type1, __ds_type2> __pair_type;
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return __pair_type(std::forward<_T1>(__x), std::forward<_T2>(__y));
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}
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#else
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template<class _T1, class _T2>
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inline pair<_T1, _T2>
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make_pair(_T1 __x, _T2 __y)
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{ return pair<_T1, _T2>(__x, __y); }
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#endif
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/// @}
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_GLIBCXX_END_NAMESPACE_VERSION
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} // namespace std
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#endif /* _STL_PAIR_H */
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