libstdc++-v3/include/std/utility

   1 // <utility> -*- C++ -*-
   2
   3 // Copyright (C) 2001-2013 Free Software Foundation, Inc.
   4 //
   5 // This file is part of the GNU ISO C++ Library.  This library is free
   6 // software; you can redistribute it and/or modify it under the
   7 // terms of the GNU General Public License as published by the
   8 // Free Software Foundation; either version 3, or (at your option)
   9 // any later version.
  10
  11 // This library is distributed in the hope that it will be useful,
  12 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 // GNU General Public License for more details.
  15
  16 // Under Section 7 of GPL version 3, you are granted additional
  17 // permissions described in the GCC Runtime Library Exception, version
  18 // 3.1, as published by the Free Software Foundation.
  19
  20 // You should have received a copy of the GNU General Public License and
  21 // a copy of the GCC Runtime Library Exception along with this program;
  22 // see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
  23 // <http://www.gnu.org/licenses/>.
  24
  25 /*
  26  *
  27  * Copyright (c) 1994
  28  * Hewlett-Packard Company
  29  *
  30  * Permission to use, copy, modify, distribute and sell this software
  31  * and its documentation for any purpose is hereby granted without fee,
  32  * provided that the above copyright notice appear in all copies and
  33  * that both that copyright notice and this permission notice appear
  34  * in supporting documentation.  Hewlett-Packard Company makes no
  35  * representations about the suitability of this software for any
  36  * purpose.  It is provided "as is" without express or implied warranty.
  37  *
  38  *
  39  * Copyright (c) 1996,1997
  40  * Silicon Graphics Computer Systems, Inc.
  41  *
  42  * Permission to use, copy, modify, distribute and sell this software
  43  * and its documentation for any purpose is hereby granted without fee,
  44  * provided that the above copyright notice appear in all copies and
  45  * that both that copyright notice and this permission notice appear
  46  * in supporting documentation.  Silicon Graphics makes no
  47  * representations about the suitability of this software for any
  48  * purpose.  It is provided "as is" without express or implied warranty.
  49  */
  50
  51 /** @file include/utility
  52  *  This is a Standard C++ Library header.
  53  */
  54
  55 #ifndef _GLIBCXX_UTILITY
  56 #define _GLIBCXX_UTILITY 1
  57
  58 #pragma GCC system_header
  59
  60 /**
  61  * @defgroup utilities Utilities
  62  *
  63  * Components deemed generally useful. Includes pair, tuple,
  64  * forward/move helpers, ratio, function object, metaprogramming and
  65  * type traits, time, date, and memory functions.
  66  */
  67
  68 #include <bits/c++config.h>
  69 #include <bits/stl_relops.h>
  70 #include <bits/stl_pair.h>
  71
  72 #if __cplusplus >= 201103L
  73 #include <bits/move.h>
  74 #include <initializer_list>
  75
  76 namespace std _GLIBCXX_VISIBILITY(default)
  77 {
  78 _GLIBCXX_BEGIN_NAMESPACE_VERSION
  79
  80   template<class _Tp>
  81     class tuple_size;
  82
  83   template<std::size_t _Int, class _Tp>
  84     class tuple_element;
  85
  86    // Various functions which give std::pair a tuple-like interface.
  87   template<class _Tp1, class _Tp2>
  88     struct tuple_size<std::pair<_Tp1, _Tp2>>
  89     : public integral_constant<std::size_t, 2> { };
  90
  91   template<class _Tp1, class _Tp2>
  92     struct tuple_element<0, std::pair<_Tp1, _Tp2>>
  93     { typedef _Tp1 type; };
  94
  95   template<class _Tp1, class _Tp2>
  96     struct tuple_element<1, std::pair<_Tp1, _Tp2>>
  97     { typedef _Tp2 type; };
  98
  99   template<std::size_t _Int>
 100     struct __pair_get;
 101
 102   template<>
 103     struct __pair_get<0>
 104     {
 105       template<typename _Tp1, typename _Tp2>
 106         static constexpr _Tp1&
 107         __get(std::pair<_Tp1, _Tp2>& __pair) noexcept
 108         { return __pair.first; }
 109
 110       template<typename _Tp1, typename _Tp2>
 111         static constexpr _Tp1&&
 112         __move_get(std::pair<_Tp1, _Tp2>&& __pair) noexcept
 113         { return std::forward<_Tp1>(__pair.first); }
 114
 115       template<typename _Tp1, typename _Tp2>
 116         static constexpr const _Tp1&
 117         __const_get(const std::pair<_Tp1, _Tp2>& __pair) noexcept
 118         { return __pair.first; }
 119     };
 120
 121   template<>
 122     struct __pair_get<1>
 123     {
 124       template<typename _Tp1, typename _Tp2>
 125         static constexpr _Tp2&
 126         __get(std::pair<_Tp1, _Tp2>& __pair) noexcept
 127         { return __pair.second; }
 128
 129       template<typename _Tp1, typename _Tp2>
 130         static constexpr _Tp2&&
 131         __move_get(std::pair<_Tp1, _Tp2>&& __pair) noexcept
 132         { return std::forward<_Tp2>(__pair.second); }
 133
 134       template<typename _Tp1, typename _Tp2>
 135         static constexpr const _Tp2&
 136         __const_get(const std::pair<_Tp1, _Tp2>& __pair) noexcept
 137         { return __pair.second; }
 138     };
 139
 140   template<std::size_t _Int, class _Tp1, class _Tp2>
 141     constexpr typename tuple_element<_Int, std::pair<_Tp1, _Tp2>>::type&
 142     get(std::pair<_Tp1, _Tp2>& __in) noexcept
 143     { return __pair_get<_Int>::__get(__in); }
 144
 145   template<std::size_t _Int, class _Tp1, class _Tp2>
 146     constexpr typename tuple_element<_Int, std::pair<_Tp1, _Tp2>>::type&&
 147     get(std::pair<_Tp1, _Tp2>&& __in) noexcept
 148     { return __pair_get<_Int>::__move_get(std::move(__in)); }
 149
 150   template<std::size_t _Int, class _Tp1, class _Tp2>
 151     constexpr const typename tuple_element<_Int, std::pair<_Tp1, _Tp2>>::type&
 152     get(const std::pair<_Tp1, _Tp2>& __in) noexcept
 153     { return __pair_get<_Int>::__const_get(__in); }
 154
 155 #if __cplusplus > 201103L
 156   /// Assign @p __new_val to @p __obj and return its previous value.
 157   template <class _Tp, class _Up = _Tp>
 158     inline _Tp
 159     exchange(_Tp& __obj, _Up&& __new_val)
 160     {
 161       _Tp __old_val = std::move(__obj);
 162       __obj = std::forward<_Up>(__new_val);
 163       return __old_val;
 164     }
 165 #endif
 166
 167 _GLIBCXX_END_NAMESPACE_VERSION
 168 } // namespace
 169
 170 #endif
 171
 172 #endif /* _GLIBCXX_UTILITY */