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 #if __cplusplus > 201402L
  79 #include <exception>
  80 #endif
  81
  82 namespace std _GLIBCXX_VISIBILITY(default)
  83 {
  84 _GLIBCXX_BEGIN_NAMESPACE_VERSION
  85
  86   /// Finds the size of a given tuple type.
  87   template<typename _Tp>
  88     struct tuple_size;
  89
  90   // _GLIBCXX_RESOLVE_LIB_DEFECTS
  91   // 2313. tuple_size should always derive from integral_constant<size_t, N>
  92   template<typename _Tp>
  93     struct tuple_size<const _Tp>
  94     : integral_constant<size_t, tuple_size<_Tp>::value> { };
  95
  96   template<typename _Tp>
  97     struct tuple_size<volatile _Tp>
  98     : integral_constant<size_t, tuple_size<_Tp>::value> { };
  99
 100   template<typename _Tp>
 101     struct tuple_size<const volatile _Tp>
 102     : integral_constant<size_t, tuple_size<_Tp>::value> { };
 103
 104   /// Gives the type of the ith element of a given tuple type.
 105   template<std::size_t __i, typename _Tp>
 106     struct tuple_element;
 107
 108   // Duplicate of C++14's tuple_element_t for internal use in C++11 mode
 109   template<std::size_t __i, typename _Tp>
 110     using __tuple_element_t = typename tuple_element<__i, _Tp>::type;
 111
 112   template<std::size_t __i, typename _Tp>
 113     struct tuple_element<__i, const _Tp>
 114     {
 115       typedef typename add_const<__tuple_element_t<__i, _Tp>>::type type;
 116     };
 117
 118   template<std::size_t __i, typename _Tp>
 119     struct tuple_element<__i, volatile _Tp>
 120     {
 121       typedef typename add_volatile<__tuple_element_t<__i, _Tp>>::type type;
 122     };
 123
 124   template<std::size_t __i, typename _Tp>
 125     struct tuple_element<__i, const volatile _Tp>
 126     {
 127       typedef typename add_cv<__tuple_element_t<__i, _Tp>>::type type;
 128     };
 129
 130 #if __cplusplus > 201103L
 131 #define __cpp_lib_tuple_element_t 201402
 132
 133   template<std::size_t __i, typename _Tp>
 134     using tuple_element_t = typename tuple_element<__i, _Tp>::type;
 135 #endif
 136
 137   template<typename>
 138     struct __is_tuple_like_impl : false_type
 139     { };
 140
 141   // Various functions which give std::pair a tuple-like interface.
 142
 143   /// Partial specialization for std::pair
 144   template<typename _T1, typename _T2>
 145     struct __is_tuple_like_impl<std::pair<_T1, _T2>> : true_type
 146     { };
 147
 148   /// Partial specialization for std::pair
 149   template<class _Tp1, class _Tp2>
 150     struct tuple_size<std::pair<_Tp1, _Tp2>>
 151     : public integral_constant<std::size_t, 2> { };
 152
 153   /// Partial specialization for std::pair
 154   template<class _Tp1, class _Tp2>
 155     struct tuple_element<0, std::pair<_Tp1, _Tp2>>
 156     { typedef _Tp1 type; };
 157
 158   /// Partial specialization for std::pair
 159   template<class _Tp1, class _Tp2>
 160     struct tuple_element<1, std::pair<_Tp1, _Tp2>>
 161     { typedef _Tp2 type; };
 162
 163   template<std::size_t _Int>
 164     struct __pair_get;
 165
 166   template<>
 167     struct __pair_get<0>
 168     {
 169       template<typename _Tp1, typename _Tp2>
 170         static constexpr _Tp1&
 171         __get(std::pair<_Tp1, _Tp2>& __pair) noexcept
 172         { return __pair.first; }
 173
 174       template<typename _Tp1, typename _Tp2>
 175         static constexpr _Tp1&&
 176         __move_get(std::pair<_Tp1, _Tp2>&& __pair) noexcept
 177         { return std::forward<_Tp1>(__pair.first); }
 178
 179       template<typename _Tp1, typename _Tp2>
 180         static constexpr const _Tp1&
 181         __const_get(const std::pair<_Tp1, _Tp2>& __pair) noexcept
 182         { return __pair.first; }
 183     };
 184
 185   template<>
 186     struct __pair_get<1>
 187     {
 188       template<typename _Tp1, typename _Tp2>
 189         static constexpr _Tp2&
 190         __get(std::pair<_Tp1, _Tp2>& __pair) noexcept
 191         { return __pair.second; }
 192
 193       template<typename _Tp1, typename _Tp2>
 194         static constexpr _Tp2&&
 195         __move_get(std::pair<_Tp1, _Tp2>&& __pair) noexcept
 196         { return std::forward<_Tp2>(__pair.second); }
 197
 198       template<typename _Tp1, typename _Tp2>
 199         static constexpr const _Tp2&
 200         __const_get(const std::pair<_Tp1, _Tp2>& __pair) noexcept
 201         { return __pair.second; }
 202     };
 203
 204   template<std::size_t _Int, class _Tp1, class _Tp2>
 205     constexpr typename tuple_element<_Int, std::pair<_Tp1, _Tp2>>::type&
 206     get(std::pair<_Tp1, _Tp2>& __in) noexcept
 207     { return __pair_get<_Int>::__get(__in); }
 208
 209   template<std::size_t _Int, class _Tp1, class _Tp2>
 210     constexpr typename tuple_element<_Int, std::pair<_Tp1, _Tp2>>::type&&
 211     get(std::pair<_Tp1, _Tp2>&& __in) noexcept
 212     { return __pair_get<_Int>::__move_get(std::move(__in)); }
 213
 214   template<std::size_t _Int, class _Tp1, class _Tp2>
 215     constexpr const typename tuple_element<_Int, std::pair<_Tp1, _Tp2>>::type&
 216     get(const std::pair<_Tp1, _Tp2>& __in) noexcept
 217     { return __pair_get<_Int>::__const_get(__in); }
 218
 219 #if __cplusplus > 201103L
 220
 221 #define __cpp_lib_tuples_by_type 201304
 222
 223   template <typename _Tp, typename _Up>
 224     constexpr _Tp&
 225     get(pair<_Tp, _Up>& __p) noexcept
 226     { return __p.first; }
 227
 228   template <typename _Tp, typename _Up>
 229     constexpr const _Tp&
 230     get(const pair<_Tp, _Up>& __p) noexcept
 231     { return __p.first; }
 232
 233   template <typename _Tp, typename _Up>
 234     constexpr _Tp&&
 235     get(pair<_Tp, _Up>&& __p) noexcept
 236     { return std::move(__p.first); }
 237
 238   template <typename _Tp, typename _Up>
 239     constexpr _Tp&
 240     get(pair<_Up, _Tp>& __p) noexcept
 241     { return __p.second; }
 242
 243   template <typename _Tp, typename _Up>
 244     constexpr const _Tp&
 245     get(const pair<_Up, _Tp>& __p) noexcept
 246     { return __p.second; }
 247
 248   template <typename _Tp, typename _Up>
 249     constexpr _Tp&&
 250     get(pair<_Up, _Tp>&& __p) noexcept
 251     { return std::move(__p.second); }
 252
 253 #define __cpp_lib_exchange_function 201304
 254
 255   /// Assign @p __new_val to @p __obj and return its previous value.
 256   template <typename _Tp, typename _Up = _Tp>
 257     inline _Tp
 258     exchange(_Tp& __obj, _Up&& __new_val)
 259     { return std::__exchange(__obj, std::forward<_Up>(__new_val)); }
 260 #endif
 261
 262   // Stores a tuple of indices.  Used by tuple and pair, and by bind() to
 263   // extract the elements in a tuple.
 264   template<size_t... _Indexes> struct _Index_tuple { };
 265
 266   // Concatenates two _Index_tuples.
 267   template<typename _Itup1, typename _Itup2> struct _Itup_cat;
 268
 269   template<size_t... _Ind1, size_t... _Ind2>
 270     struct _Itup_cat<_Index_tuple<_Ind1...>, _Index_tuple<_Ind2...>>
 271     {
 272       using __type = _Index_tuple<_Ind1..., (_Ind2 + sizeof...(_Ind1))...>;
 273     };
 274
 275   // Builds an _Index_tuple<0, 1, 2, ..., _Num-1>.
 276   template<size_t _Num>
 277     struct _Build_index_tuple
 278     : _Itup_cat<typename _Build_index_tuple<_Num / 2>::__type,
 279                 typename _Build_index_tuple<_Num - _Num / 2>::__type>
 280     { };
 281
 282   template<>
 283     struct _Build_index_tuple<1>
 284     {
 285       typedef _Index_tuple<0> __type;
 286     };
 287
 288   template<>
 289     struct _Build_index_tuple<0>
 290     {
 291       typedef _Index_tuple<> __type;
 292     };
 293
 294 #if __cplusplus > 201103L
 295
 296 #define __cpp_lib_integer_sequence 201304
 297
 298   /// Class template integer_sequence
 299   template<typename _Tp, _Tp... _Idx>
 300     struct integer_sequence
 301     {
 302       typedef _Tp value_type;
 303       static constexpr size_t size() { return sizeof...(_Idx); }
 304     };
 305
 306   template<typename _Tp, _Tp _Num,
 307            typename _ISeq = typename _Build_index_tuple<_Num>::__type>
 308     struct _Make_integer_sequence;
 309
 310   template<typename _Tp, _Tp _Num,  size_t... _Idx>
 311     struct _Make_integer_sequence<_Tp, _Num, _Index_tuple<_Idx...>>
 312     {
 313       static_assert( _Num >= 0,
 314                      "Cannot make integer sequence of negative length" );
 315
 316       typedef integer_sequence<_Tp, static_cast<_Tp>(_Idx)...> __type;
 317     };
 318
 319   /// Alias template make_integer_sequence
 320   template<typename _Tp, _Tp _Num>
 321     using make_integer_sequence
 322       = typename _Make_integer_sequence<_Tp, _Num>::__type;
 323
 324   /// Alias template index_sequence
 325   template<size_t... _Idx>
 326     using index_sequence = integer_sequence<size_t, _Idx...>;
 327
 328   /// Alias template make_index_sequence
 329   template<size_t _Num>
 330     using make_index_sequence = make_integer_sequence<size_t, _Num>;
 331
 332   /// Alias template index_sequence_for
 333   template<typename... _Types>
 334     using index_sequence_for = make_index_sequence<sizeof...(_Types)>;
 335 #endif
 336
 337 #if __cplusplus > 201402L
 338
 339   struct in_place_tag {
 340     in_place_tag() = delete;
 341   };
 342
 343   struct __in_place;
 344   template<typename _Tp> struct __in_place_type;
 345   template<size_t _Idx> struct __in_place_index;
 346
 347   using in_place_t = in_place_tag(&)(__in_place*);
 348   template <class _Tp>
 349     using in_place_type_t = in_place_tag(&)(__in_place_type<_Tp>*);
 350   template <int _Idx>
 351     using in_place_index_t = in_place_tag(&)(__in_place_index<_Idx>*);
 352
 353   inline in_place_tag in_place(__in_place*) {terminate();}
 354   template <class _Tp>
 355     in_place_tag in_place(__in_place_type<_Tp>*) {terminate();}
 356   template <size_t _Idx>
 357     in_place_tag in_place(__in_place_index<_Idx>*) {terminate();}
 358
 359   template<typename>
 360     struct __is_in_place_type_impl : false_type
 361     { };
 362
 363   template<typename _Tp>
 364     struct __is_in_place_type_impl<in_place_type_t<_Tp>> : true_type
 365     { };
 366
 367   template<typename _Tp>
 368     struct __is_in_place_type
 369       : public __is_in_place_type_impl<_Tp>
 370     { };
 371
 372 #define  __cpp_lib_as_const 201510
 373   template<typename _Tp>
 374     constexpr add_const_t<_Tp>& as_const(_Tp& __t) noexcept { return __t; }
 375
 376   template<typename _Tp>
 377     void as_const(const _Tp&&) = delete;
 378
 379 #endif // C++17
 380
 381 _GLIBCXX_END_NAMESPACE_VERSION
 382 } // namespace
 383
 384 #endif
 385
 386 #endif /* _GLIBCXX_UTILITY */