libstdc++-v3/include/std/utility

   1 // <utility> -*- C++ -*-
   2
   3 // Copyright (C) 2001-2016 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
  74 #include <type_traits>
  75 #include <bits/move.h>
  76 #include <initializer_list>
  77
  78 namespace std _GLIBCXX_VISIBILITY(default)
  79 {
  80 _GLIBCXX_BEGIN_NAMESPACE_VERSION
  81
  82   /// Finds the size of a given tuple type.
  83   template<typename _Tp>
  84     struct tuple_size;
  85
  86   // _GLIBCXX_RESOLVE_LIB_DEFECTS
  87   // 2313. tuple_size should always derive from integral_constant<size_t, N>
  88   template<typename _Tp>
  89     struct tuple_size<const _Tp>
  90     : integral_constant<size_t, tuple_size<_Tp>::value> { };
  91
  92   template<typename _Tp>
  93     struct tuple_size<volatile _Tp>
  94     : integral_constant<size_t, tuple_size<_Tp>::value> { };
  95
  96   template<typename _Tp>
  97     struct tuple_size<const volatile _Tp>
  98     : integral_constant<size_t, tuple_size<_Tp>::value> { };
  99
 100   /// Gives the type of the ith element of a given tuple type.
 101   template<std::size_t __i, typename _Tp>
 102     struct tuple_element;
 103
 104   // Duplicate of C++14's tuple_element_t for internal use in C++11 mode
 105   template<std::size_t __i, typename _Tp>
 106     using __tuple_element_t = typename tuple_element<__i, _Tp>::type;
 107
 108   template<std::size_t __i, typename _Tp>
 109     struct tuple_element<__i, const _Tp>
 110     {
 111       typedef typename add_const<__tuple_element_t<__i, _Tp>>::type type;
 112     };
 113
 114   template<std::size_t __i, typename _Tp>
 115     struct tuple_element<__i, volatile _Tp>
 116     {
 117       typedef typename add_volatile<__tuple_element_t<__i, _Tp>>::type type;
 118     };
 119
 120   template<std::size_t __i, typename _Tp>
 121     struct tuple_element<__i, const volatile _Tp>
 122     {
 123       typedef typename add_cv<__tuple_element_t<__i, _Tp>>::type type;
 124     };
 125
 126 #if __cplusplus > 201103L
 127 #define __cpp_lib_tuple_element_t 201402
 128
 129   template<std::size_t __i, typename _Tp>
 130     using tuple_element_t = typename tuple_element<__i, _Tp>::type;
 131 #endif
 132
 133   template<typename>
 134     struct __is_tuple_like_impl : false_type
 135     { };
 136
 137   // Various functions which give std::pair a tuple-like interface.
 138
 139   /// Partial specialization for std::pair
 140   template<typename _T1, typename _T2>
 141     struct __is_tuple_like_impl<std::pair<_T1, _T2>> : true_type
 142     { };
 143
 144   /// Partial specialization for std::pair
 145   template<class _Tp1, class _Tp2>
 146     struct tuple_size<std::pair<_Tp1, _Tp2>>
 147     : public integral_constant<std::size_t, 2> { };
 148
 149   /// Partial specialization for std::pair
 150   template<class _Tp1, class _Tp2>
 151     struct tuple_element<0, std::pair<_Tp1, _Tp2>>
 152     { typedef _Tp1 type; };
 153
 154   /// Partial specialization for std::pair
 155   template<class _Tp1, class _Tp2>
 156     struct tuple_element<1, std::pair<_Tp1, _Tp2>>
 157     { typedef _Tp2 type; };
 158
 159   template<std::size_t _Int>
 160     struct __pair_get;
 161
 162   template<>
 163     struct __pair_get<0>
 164     {
 165       template<typename _Tp1, typename _Tp2>
 166         static constexpr _Tp1&
 167         __get(std::pair<_Tp1, _Tp2>& __pair) noexcept
 168         { return __pair.first; }
 169
 170       template<typename _Tp1, typename _Tp2>
 171         static constexpr _Tp1&&
 172         __move_get(std::pair<_Tp1, _Tp2>&& __pair) noexcept
 173         { return std::forward<_Tp1>(__pair.first); }
 174
 175       template<typename _Tp1, typename _Tp2>
 176         static constexpr const _Tp1&
 177         __const_get(const std::pair<_Tp1, _Tp2>& __pair) noexcept
 178         { return __pair.first; }
 179     };
 180
 181   template<>
 182     struct __pair_get<1>
 183     {
 184       template<typename _Tp1, typename _Tp2>
 185         static constexpr _Tp2&
 186         __get(std::pair<_Tp1, _Tp2>& __pair) noexcept
 187         { return __pair.second; }
 188
 189       template<typename _Tp1, typename _Tp2>
 190         static constexpr _Tp2&&
 191         __move_get(std::pair<_Tp1, _Tp2>&& __pair) noexcept
 192         { return std::forward<_Tp2>(__pair.second); }
 193
 194       template<typename _Tp1, typename _Tp2>
 195         static constexpr const _Tp2&
 196         __const_get(const std::pair<_Tp1, _Tp2>& __pair) noexcept
 197         { return __pair.second; }
 198     };
 199
 200   template<std::size_t _Int, class _Tp1, class _Tp2>
 201     constexpr typename tuple_element<_Int, std::pair<_Tp1, _Tp2>>::type&
 202     get(std::pair<_Tp1, _Tp2>& __in) noexcept
 203     { return __pair_get<_Int>::__get(__in); }
 204
 205   template<std::size_t _Int, class _Tp1, class _Tp2>
 206     constexpr typename tuple_element<_Int, std::pair<_Tp1, _Tp2>>::type&&
 207     get(std::pair<_Tp1, _Tp2>&& __in) noexcept
 208     { return __pair_get<_Int>::__move_get(std::move(__in)); }
 209
 210   template<std::size_t _Int, class _Tp1, class _Tp2>
 211     constexpr const typename tuple_element<_Int, std::pair<_Tp1, _Tp2>>::type&
 212     get(const std::pair<_Tp1, _Tp2>& __in) noexcept
 213     { return __pair_get<_Int>::__const_get(__in); }
 214
 215 #if __cplusplus > 201103L
 216
 217 #define __cpp_lib_tuples_by_type 201304
 218
 219   template <typename _Tp, typename _Up>
 220     constexpr _Tp&
 221     get(pair<_Tp, _Up>& __p) noexcept
 222     { return __p.first; }
 223
 224   template <typename _Tp, typename _Up>
 225     constexpr const _Tp&
 226     get(const pair<_Tp, _Up>& __p) noexcept
 227     { return __p.first; }
 228
 229   template <typename _Tp, typename _Up>
 230     constexpr _Tp&&
 231     get(pair<_Tp, _Up>&& __p) noexcept
 232     { return std::move(__p.first); }
 233
 234   template <typename _Tp, typename _Up>
 235     constexpr _Tp&
 236     get(pair<_Up, _Tp>& __p) noexcept
 237     { return __p.second; }
 238
 239   template <typename _Tp, typename _Up>
 240     constexpr const _Tp&
 241     get(const pair<_Up, _Tp>& __p) noexcept
 242     { return __p.second; }
 243
 244   template <typename _Tp, typename _Up>
 245     constexpr _Tp&&
 246     get(pair<_Up, _Tp>&& __p) noexcept
 247     { return std::move(__p.second); }
 248
 249 #define __cpp_lib_exchange_function 201304
 250
 251   /// Assign @p __new_val to @p __obj and return its previous value.
 252   template <typename _Tp, typename _Up = _Tp>
 253     inline _Tp
 254     exchange(_Tp& __obj, _Up&& __new_val)
 255     { return std::__exchange(__obj, std::forward<_Up>(__new_val)); }
 256 #endif
 257
 258   // Stores a tuple of indices.  Used by tuple and pair, and by bind() to
 259   // extract the elements in a tuple.
 260   template<size_t... _Indexes> struct _Index_tuple { };
 261
 262   // Concatenates two _Index_tuples.
 263   template<typename _Itup1, typename _Itup2> struct _Itup_cat;
 264
 265   template<size_t... _Ind1, size_t... _Ind2>
 266     struct _Itup_cat<_Index_tuple<_Ind1...>, _Index_tuple<_Ind2...>>
 267     {
 268       using __type = _Index_tuple<_Ind1..., (_Ind2 + sizeof...(_Ind1))...>;
 269     };
 270
 271   // Builds an _Index_tuple<0, 1, 2, ..., _Num-1>.
 272   template<size_t _Num>
 273     struct _Build_index_tuple
 274     : _Itup_cat<typename _Build_index_tuple<_Num / 2>::__type,
 275                 typename _Build_index_tuple<_Num - _Num / 2>::__type>
 276     { };
 277
 278   template<>
 279     struct _Build_index_tuple<1>
 280     {
 281       typedef _Index_tuple<0> __type;
 282     };
 283
 284   template<>
 285     struct _Build_index_tuple<0>
 286     {
 287       typedef _Index_tuple<> __type;
 288     };
 289
 290 #if __cplusplus > 201103L
 291
 292 #define __cpp_lib_integer_sequence 201304
 293
 294   /// Class template integer_sequence
 295   template<typename _Tp, _Tp... _Idx>
 296     struct integer_sequence
 297     {
 298       typedef _Tp value_type;
 299       static constexpr size_t size() { return sizeof...(_Idx); }
 300     };
 301
 302   template<typename _Tp, _Tp _Num,
 303            typename _ISeq = typename _Build_index_tuple<_Num>::__type>
 304     struct _Make_integer_sequence;
 305
 306   template<typename _Tp, _Tp _Num,  size_t... _Idx>
 307     struct _Make_integer_sequence<_Tp, _Num, _Index_tuple<_Idx...>>
 308     {
 309       static_assert( _Num >= 0,
 310                      "Cannot make integer sequence of negative length" );
 311
 312       typedef integer_sequence<_Tp, static_cast<_Tp>(_Idx)...> __type;
 313     };
 314
 315   /// Alias template make_integer_sequence
 316   template<typename _Tp, _Tp _Num>
 317     using make_integer_sequence
 318       = typename _Make_integer_sequence<_Tp, _Num>::__type;
 319
 320   /// Alias template index_sequence
 321   template<size_t... _Idx>
 322     using index_sequence = integer_sequence<size_t, _Idx...>;
 323
 324   /// Alias template make_index_sequence
 325   template<size_t _Num>
 326     using make_index_sequence = make_integer_sequence<size_t, _Num>;
 327
 328   /// Alias template index_sequence_for
 329   template<typename... _Types>
 330     using index_sequence_for = make_index_sequence<sizeof...(_Types)>;
 331 #endif
 332
 333 _GLIBCXX_END_NAMESPACE_VERSION
 334 } // namespace
 335
 336 #endif
 337
 338 #endif /* _GLIBCXX_UTILITY */