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// Pair implementation -*- C++ -*- |
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|
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// Copyright (C) 2001-2021 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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|
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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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|
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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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|
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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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* |
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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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|
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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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|
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#ifndef _STL_PAIR_H |
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#define _STL_PAIR_H 1 |
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|
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#include <bits/move.h> // for std::move / std::forward, and std::swap |
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|
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#if __cplusplus >= 201103L |
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# include <type_traits> // for std::__decay_and_strip, std::is_reference_v |
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#endif |
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#if __cplusplus > 201703L |
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# include <compare> |
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# define __cpp_lib_constexpr_utility 201811L |
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#endif |
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|
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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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/** |
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* @addtogroup utilities |
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* @{ |
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*/ |
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|
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#if __cplusplus >= 201103L |
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/// Tag type for piecewise construction of std::pair objects. |
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struct piecewise_construct_t { explicit piecewise_construct_t() = default; }; |
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|
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/// Tag for piecewise construction of std::pair objects. |
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_GLIBCXX17_INLINE constexpr piecewise_construct_t piecewise_construct = |
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piecewise_construct_t(); |
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|
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/// @cond undocumented |
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|
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// Forward declarations. |
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template<typename...> |
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class tuple; |
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|
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template<size_t...> |
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struct _Index_tuple; |
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|
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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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|
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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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|
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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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|
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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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|
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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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|
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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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|
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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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|
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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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|
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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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|
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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 // C++11 |
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|
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template<typename _U1, typename _U2> class __pair_base |
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{ |
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#if __cplusplus >= 201103L |
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template<typename _T1, typename _T2> friend struct pair; |
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__pair_base() = default; |
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~__pair_base() = default; |
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__pair_base(const __pair_base&) = default; |
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__pair_base& operator=(const __pair_base&) = delete; |
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#endif // C++11 |
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}; |
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|
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/// @endcond |
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|
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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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* <https://gcc.gnu.org/onlinedocs/libstdc++/manual/utilities.html> |
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*/ |
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template<typename _T1, typename _T2> |
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struct pair |
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: private __pair_base<_T1, _T2> |
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{ |
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typedef _T1 first_type; ///< The type of the `first` member |
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typedef _T2 second_type; ///< The type of the `second` member |
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|
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_T1 first; ///< The first member |
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_T2 second; ///< The second member |
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|
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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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|
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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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|
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#if __cplusplus < 201103L |
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/// Two objects may be passed to a @c pair constructor to be copied. |
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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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/// @cond undocumented |
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using _PCCP = _PCC<true, _T1, _T2>; |
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/// @endcond |
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|
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/// Construct from two const lvalues, allowing implicit conversions. |
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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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|
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/// Construct from two const lvalues, disallowing implicit conversions. |
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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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|
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#if __cplusplus < 201103L |
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/// There is also a templated constructor to convert from other pairs. |
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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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/// @cond undocumented |
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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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/// @endcond |
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|
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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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|
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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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#endif |
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|
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#if __cplusplus >= 201103L |
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constexpr pair(const pair&) = default; ///< Copy constructor |
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constexpr pair(pair&&) = default; ///< Move constructor |
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|
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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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|
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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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|
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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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|
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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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|
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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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|
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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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|
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|
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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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|
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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 |
| 379 |
_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)) { } |
| 384 |
|
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template<typename... _Args1, typename... _Args2> |
| 386 |
_GLIBCXX20_CONSTEXPR |
| 387 |
pair(piecewise_construct_t, tuple<_Args1...>, tuple<_Args2...>); |
| 388 |
|
| 389 |
_GLIBCXX20_CONSTEXPR pair& |
| 390 |
operator=(typename conditional< |
| 391 |
__and_<is_copy_assignable<_T1>, |
| 392 |
is_copy_assignable<_T2>>::value, |
| 393 |
const pair&, const __nonesuch&>::type __p) |
| 394 |
{ |
| 395 |
first = __p.first; |
| 396 |
second = __p.second; |
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return *this; |
| 398 |
} |
| 399 |
|
| 400 |
_GLIBCXX20_CONSTEXPR pair& |
| 401 |
operator=(typename conditional< |
| 402 |
__and_<is_move_assignable<_T1>, |
| 403 |
is_move_assignable<_T2>>::value, |
| 404 |
pair&&, __nonesuch&&>::type __p) |
| 405 |
noexcept(__and_<is_nothrow_move_assignable<_T1>, |
| 406 |
is_nothrow_move_assignable<_T2>>::value) |
| 407 |
{ |
| 408 |
first = std::forward<first_type>(__p.first); |
| 409 |
second = std::forward<second_type>(__p.second); |
| 410 |
return *this; |
| 411 |
} |
| 412 |
|
| 413 |
template<typename _U1, typename _U2> |
| 414 |
_GLIBCXX20_CONSTEXPR |
| 415 |
typename enable_if<__and_<is_assignable<_T1&, const _U1&>, |
| 416 |
is_assignable<_T2&, const _U2&>>::value, |
| 417 |
pair&>::type |
| 418 |
operator=(const pair<_U1, _U2>& __p) |
| 419 |
{ |
| 420 |
first = __p.first; |
| 421 |
second = __p.second; |
| 422 |
return *this; |
| 423 |
} |
| 424 |
|
| 425 |
template<typename _U1, typename _U2> |
| 426 |
_GLIBCXX20_CONSTEXPR |
| 427 |
typename enable_if<__and_<is_assignable<_T1&, _U1&&>, |
| 428 |
is_assignable<_T2&, _U2&&>>::value, |
| 429 |
pair&>::type |
| 430 |
operator=(pair<_U1, _U2>&& __p) |
| 431 |
{ |
| 432 |
first = std::forward<_U1>(__p.first); |
| 433 |
second = std::forward<_U2>(__p.second); |
| 434 |
return *this; |
| 435 |
} |
| 436 |
|
| 437 |
/// Swap the first members and then the second members. |
| 438 |
_GLIBCXX20_CONSTEXPR void |
| 439 |
swap(pair& __p) |
| 440 |
noexcept(__and_<__is_nothrow_swappable<_T1>, |
| 441 |
__is_nothrow_swappable<_T2>>::value) |
| 442 |
{ |
| 443 |
using std::swap; |
| 444 |
swap(first, __p.first); |
| 445 |
swap(second, __p.second); |
| 446 |
} |
| 447 |
|
| 448 |
private: |
| 449 |
template<typename... _Args1, size_t... _Indexes1, |
| 450 |
typename... _Args2, size_t... _Indexes2> |
| 451 |
_GLIBCXX20_CONSTEXPR |
| 452 |
pair(tuple<_Args1...>&, tuple<_Args2...>&, |
| 453 |
_Index_tuple<_Indexes1...>, _Index_tuple<_Indexes2...>); |
| 454 |
#endif // C++11 |
| 455 |
}; |
| 456 |
|
| 457 |
/// @relates pair @{ |
| 458 |
|
| 459 |
#if __cpp_deduction_guides >= 201606 |
| 460 |
template<typename _T1, typename _T2> pair(_T1, _T2) -> pair<_T1, _T2>; |
| 461 |
#endif |
| 462 |
|
| 463 |
/// Two pairs of the same type are equal iff their members are equal. |
| 464 |
template<typename _T1, typename _T2> |
| 465 |
inline _GLIBCXX_CONSTEXPR bool |
| 466 |
operator==(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y) |
| 467 |
{ return __x.first == __y.first && __x.second == __y.second; } |
| 468 |
|
| 469 |
#if __cpp_lib_three_way_comparison && __cpp_lib_concepts |
| 470 |
template<typename _T1, typename _T2> |
| 471 |
constexpr common_comparison_category_t<__detail::__synth3way_t<_T1>, |
| 472 |
__detail::__synth3way_t<_T2>> |
| 473 |
operator<=>(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y) |
| 474 |
{ |
| 475 |
if (auto __c = __detail::__synth3way(__x.first, __y.first); __c != 0) |
| 476 |
return __c; |
| 477 |
return __detail::__synth3way(__x.second, __y.second); |
| 478 |
} |
| 479 |
#else |
| 480 |
/** Defines a lexicographical order for pairs. |
| 481 |
* |
| 482 |
* For two pairs of the same type, `P` is ordered before `Q` if |
| 483 |
* `P.first` is less than `Q.first`, or if `P.first` and `Q.first` |
| 484 |
* are equivalent (neither is less than the other) and `P.second` is less |
| 485 |
* than `Q.second`. |
| 486 |
*/ |
| 487 |
template<typename _T1, typename _T2> |
| 488 |
inline _GLIBCXX_CONSTEXPR bool |
| 489 |
operator<(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y) |
| 490 |
{ return __x.first < __y.first |
| 491 |
|| (!(__y.first < __x.first) && __x.second < __y.second); } |
| 492 |
|
| 493 |
/// Uses @c operator== to find the result. |
| 494 |
template<typename _T1, typename _T2> |
| 495 |
inline _GLIBCXX_CONSTEXPR bool |
| 496 |
operator!=(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y) |
| 497 |
{ return !(__x == __y); } |
| 498 |
|
| 499 |
/// Uses @c operator< to find the result. |
| 500 |
template<typename _T1, typename _T2> |
| 501 |
inline _GLIBCXX_CONSTEXPR bool |
| 502 |
operator>(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y) |
| 503 |
{ return __y < __x; } |
| 504 |
|
| 505 |
/// Uses @c operator< to find the result. |
| 506 |
template<typename _T1, typename _T2> |
| 507 |
inline _GLIBCXX_CONSTEXPR bool |
| 508 |
operator<=(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y) |
| 509 |
{ return !(__y < __x); } |
| 510 |
|
| 511 |
/// Uses @c operator< to find the result. |
| 512 |
template<typename _T1, typename _T2> |
| 513 |
inline _GLIBCXX_CONSTEXPR bool |
| 514 |
operator>=(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y) |
| 515 |
{ return !(__x < __y); } |
| 516 |
#endif // !(three_way_comparison && concepts) |
| 517 |
|
| 518 |
#if __cplusplus >= 201103L |
| 519 |
/** Swap overload for pairs. Calls std::pair::swap(). |
| 520 |
* |
| 521 |
* @note This std::swap overload is not declared in C++03 mode, |
| 522 |
* which has performance implications, e.g. see https://gcc.gnu.org/PR38466 |
| 523 |
*/ |
| 524 |
template<typename _T1, typename _T2> |
| 525 |
_GLIBCXX20_CONSTEXPR inline |
| 526 |
#if __cplusplus > 201402L || !defined(__STRICT_ANSI__) // c++1z or gnu++11 |
| 527 |
// Constrained free swap overload, see p0185r1 |
| 528 |
typename enable_if<__and_<__is_swappable<_T1>, |
| 529 |
__is_swappable<_T2>>::value>::type |
| 530 |
#else |
| 531 |
void |
| 532 |
#endif |
| 533 |
swap(pair<_T1, _T2>& __x, pair<_T1, _T2>& __y) |
| 534 |
noexcept(noexcept(__x.swap(__y))) |
| 535 |
{ __x.swap(__y); } |
| 536 |
|
| 537 |
#if __cplusplus > 201402L || !defined(__STRICT_ANSI__) // c++1z or gnu++11 |
| 538 |
template<typename _T1, typename _T2> |
| 539 |
typename enable_if<!__and_<__is_swappable<_T1>, |
| 540 |
__is_swappable<_T2>>::value>::type |
| 541 |
swap(pair<_T1, _T2>&, pair<_T1, _T2>&) = delete; |
| 542 |
#endif |
| 543 |
#endif // __cplusplus >= 201103L |
| 544 |
|
| 545 |
/// @} relates pair |
| 546 |
|
| 547 |
/** |
| 548 |
* @brief A convenience wrapper for creating a pair from two objects. |
| 549 |
* @param __x The first object. |
| 550 |
* @param __y The second object. |
| 551 |
* @return A newly-constructed pair<> object of the appropriate type. |
| 552 |
* |
| 553 |
* The C++98 standard says the objects are passed by reference-to-const, |
| 554 |
* but C++03 says they are passed by value (this was LWG issue #181). |
| 555 |
* |
| 556 |
* Since C++11 they have been passed by forwarding reference and then |
| 557 |
* forwarded to the new members of the pair. To create a pair with a |
| 558 |
* member of reference type, pass a `reference_wrapper` to this function. |
| 559 |
*/ |
| 560 |
// _GLIBCXX_RESOLVE_LIB_DEFECTS |
| 561 |
// 181. make_pair() unintended behavior |
| 562 |
#if __cplusplus >= 201103L |
| 563 |
// NB: DR 706. |
| 564 |
template<typename _T1, typename _T2> |
| 565 |
constexpr pair<typename __decay_and_strip<_T1>::__type, |
| 566 |
typename __decay_and_strip<_T2>::__type> |
| 567 |
make_pair(_T1&& __x, _T2&& __y) |
| 568 |
{ |
| 569 |
typedef typename __decay_and_strip<_T1>::__type __ds_type1; |
| 570 |
typedef typename __decay_and_strip<_T2>::__type __ds_type2; |
| 571 |
typedef pair<__ds_type1, __ds_type2> __pair_type; |
| 572 |
return __pair_type(std::forward<_T1>(__x), std::forward<_T2>(__y)); |
| 573 |
} |
| 574 |
#else |
| 575 |
template<typename _T1, typename _T2> |
| 576 |
inline pair<_T1, _T2> |
| 577 |
make_pair(_T1 __x, _T2 __y) |
| 578 |
{ return pair<_T1, _T2>(__x, __y); } |
| 579 |
#endif |
| 580 |
|
| 581 |
/// @} |
| 582 |
|
| 583 |
_GLIBCXX_END_NAMESPACE_VERSION |
| 584 |
} // namespace std |
| 585 |
|
| 586 |
#endif /* _STL_PAIR_H */ |
