libstdc++
utility
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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 
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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  // 2770. tuple_size<const T> specialization is not SFINAE compatible
92  template<typename _Tp, typename = void>
93  struct __tuple_size_cv_impl { };
94 
95  template<typename _Tp>
96  struct __tuple_size_cv_impl<_Tp, __void_t<decltype(tuple_size<_Tp>::value)>>
97  : integral_constant<size_t, tuple_size<_Tp>::value> { };
98 
99  // _GLIBCXX_RESOLVE_LIB_DEFECTS
100  // 2313. tuple_size should always derive from integral_constant<size_t, N>
101  template<typename _Tp>
102  struct tuple_size<const _Tp> : __tuple_size_cv_impl<_Tp> { };
103 
104  template<typename _Tp>
105  struct tuple_size<volatile _Tp> : __tuple_size_cv_impl<_Tp> { };
106 
107  template<typename _Tp>
108  struct tuple_size<const volatile _Tp> : __tuple_size_cv_impl<_Tp> { };
109 
110  /// Gives the type of the ith element of a given tuple type.
111  template<std::size_t __i, typename _Tp>
112  struct tuple_element;
113 
114  // Duplicate of C++14's tuple_element_t for internal use in C++11 mode
115  template<std::size_t __i, typename _Tp>
116  using __tuple_element_t = typename tuple_element<__i, _Tp>::type;
117 
118  template<std::size_t __i, typename _Tp>
119  struct tuple_element<__i, const _Tp>
120  {
121  typedef typename add_const<__tuple_element_t<__i, _Tp>>::type type;
122  };
123 
124  template<std::size_t __i, typename _Tp>
125  struct tuple_element<__i, volatile _Tp>
126  {
127  typedef typename add_volatile<__tuple_element_t<__i, _Tp>>::type type;
128  };
129 
130  template<std::size_t __i, typename _Tp>
131  struct tuple_element<__i, const volatile _Tp>
132  {
133  typedef typename add_cv<__tuple_element_t<__i, _Tp>>::type type;
134  };
135 
136 #if __cplusplus > 201103L
137 #define __cpp_lib_tuple_element_t 201402
138 
139  template<std::size_t __i, typename _Tp>
140  using tuple_element_t = typename tuple_element<__i, _Tp>::type;
141 #endif
142 
143  template<typename>
144  struct __is_tuple_like_impl : false_type
145  { };
146 
147  // Various functions which give std::pair a tuple-like interface.
148 
149  /// Partial specialization for std::pair
150  template<typename _T1, typename _T2>
151  struct __is_tuple_like_impl<std::pair<_T1, _T2>> : true_type
152  { };
153 
154  /// Partial specialization for std::pair
155  template<class _Tp1, class _Tp2>
156  struct tuple_size<std::pair<_Tp1, _Tp2>>
157  : public integral_constant<std::size_t, 2> { };
158 
159  /// Partial specialization for std::pair
160  template<class _Tp1, class _Tp2>
161  struct tuple_element<0, std::pair<_Tp1, _Tp2>>
162  { typedef _Tp1 type; };
163 
164  /// Partial specialization for std::pair
165  template<class _Tp1, class _Tp2>
166  struct tuple_element<1, std::pair<_Tp1, _Tp2>>
167  { typedef _Tp2 type; };
168 
169  template<std::size_t _Int>
170  struct __pair_get;
171 
172  template<>
173  struct __pair_get<0>
174  {
175  template<typename _Tp1, typename _Tp2>
176  static constexpr _Tp1&
177  __get(std::pair<_Tp1, _Tp2>& __pair) noexcept
178  { return __pair.first; }
179 
180  template<typename _Tp1, typename _Tp2>
181  static constexpr _Tp1&&
182  __move_get(std::pair<_Tp1, _Tp2>&& __pair) noexcept
183  { return std::forward<_Tp1>(__pair.first); }
184 
185  template<typename _Tp1, typename _Tp2>
186  static constexpr const _Tp1&
187  __const_get(const std::pair<_Tp1, _Tp2>& __pair) noexcept
188  { return __pair.first; }
189  };
190 
191  template<>
192  struct __pair_get<1>
193  {
194  template<typename _Tp1, typename _Tp2>
195  static constexpr _Tp2&
196  __get(std::pair<_Tp1, _Tp2>& __pair) noexcept
197  { return __pair.second; }
198 
199  template<typename _Tp1, typename _Tp2>
200  static constexpr _Tp2&&
201  __move_get(std::pair<_Tp1, _Tp2>&& __pair) noexcept
202  { return std::forward<_Tp2>(__pair.second); }
203 
204  template<typename _Tp1, typename _Tp2>
205  static constexpr const _Tp2&
206  __const_get(const std::pair<_Tp1, _Tp2>& __pair) noexcept
207  { return __pair.second; }
208  };
209 
210  template<std::size_t _Int, class _Tp1, class _Tp2>
211  constexpr typename tuple_element<_Int, std::pair<_Tp1, _Tp2>>::type&
212  get(std::pair<_Tp1, _Tp2>& __in) noexcept
213  { return __pair_get<_Int>::__get(__in); }
214 
215  template<std::size_t _Int, class _Tp1, class _Tp2>
216  constexpr typename tuple_element<_Int, std::pair<_Tp1, _Tp2>>::type&&
217  get(std::pair<_Tp1, _Tp2>&& __in) noexcept
218  { return __pair_get<_Int>::__move_get(std::move(__in)); }
219 
220  template<std::size_t _Int, class _Tp1, class _Tp2>
221  constexpr const typename tuple_element<_Int, std::pair<_Tp1, _Tp2>>::type&
222  get(const std::pair<_Tp1, _Tp2>& __in) noexcept
223  { return __pair_get<_Int>::__const_get(__in); }
224 
225 #if __cplusplus > 201103L
226 
227 #define __cpp_lib_tuples_by_type 201304
228 
229  template <typename _Tp, typename _Up>
230  constexpr _Tp&
231  get(pair<_Tp, _Up>& __p) noexcept
232  { return __p.first; }
233 
234  template <typename _Tp, typename _Up>
235  constexpr const _Tp&
236  get(const pair<_Tp, _Up>& __p) noexcept
237  { return __p.first; }
238 
239  template <typename _Tp, typename _Up>
240  constexpr _Tp&&
241  get(pair<_Tp, _Up>&& __p) noexcept
242  { return std::move(__p.first); }
243 
244  template <typename _Tp, typename _Up>
245  constexpr _Tp&
246  get(pair<_Up, _Tp>& __p) noexcept
247  { return __p.second; }
248 
249  template <typename _Tp, typename _Up>
250  constexpr const _Tp&
251  get(const pair<_Up, _Tp>& __p) noexcept
252  { return __p.second; }
253 
254  template <typename _Tp, typename _Up>
255  constexpr _Tp&&
256  get(pair<_Up, _Tp>&& __p) noexcept
257  { return std::move(__p.second); }
258 
259 #define __cpp_lib_exchange_function 201304
260 
261  /// Assign @p __new_val to @p __obj and return its previous value.
262  template <typename _Tp, typename _Up = _Tp>
263  inline _Tp
264  exchange(_Tp& __obj, _Up&& __new_val)
265  { return std::__exchange(__obj, std::forward<_Up>(__new_val)); }
266 #endif
267 
268  // Stores a tuple of indices. Used by tuple and pair, and by bind() to
269  // extract the elements in a tuple.
270  template<size_t... _Indexes> struct _Index_tuple { };
271 
272  // Concatenates two _Index_tuples.
273  template<typename _Itup1, typename _Itup2> struct _Itup_cat;
274 
275  template<size_t... _Ind1, size_t... _Ind2>
276  struct _Itup_cat<_Index_tuple<_Ind1...>, _Index_tuple<_Ind2...>>
277  {
278  using __type = _Index_tuple<_Ind1..., (_Ind2 + sizeof...(_Ind1))...>;
279  };
280 
281  // Builds an _Index_tuple<0, 1, 2, ..., _Num-1>.
282  template<size_t _Num>
283  struct _Build_index_tuple
284  : _Itup_cat<typename _Build_index_tuple<_Num / 2>::__type,
285  typename _Build_index_tuple<_Num - _Num / 2>::__type>
286  { };
287 
288  template<>
289  struct _Build_index_tuple<1>
290  {
291  typedef _Index_tuple<0> __type;
292  };
293 
294  template<>
295  struct _Build_index_tuple<0>
296  {
297  typedef _Index_tuple<> __type;
298  };
299 
300 #if __cplusplus > 201103L
301 
302 #define __cpp_lib_integer_sequence 201304
303 
304  /// Class template integer_sequence
305  template<typename _Tp, _Tp... _Idx>
307  {
308  typedef _Tp value_type;
309  static constexpr size_t size() { return sizeof...(_Idx); }
310  };
311 
312  template<typename _Tp, _Tp _Num,
313  typename _ISeq = typename _Build_index_tuple<_Num>::__type>
314  struct _Make_integer_sequence;
315 
316  template<typename _Tp, _Tp _Num, size_t... _Idx>
317  struct _Make_integer_sequence<_Tp, _Num, _Index_tuple<_Idx...>>
318  {
319  static_assert( _Num >= 0,
320  "Cannot make integer sequence of negative length" );
321 
322  typedef integer_sequence<_Tp, static_cast<_Tp>(_Idx)...> __type;
323  };
324 
325  /// Alias template make_integer_sequence
326  template<typename _Tp, _Tp _Num>
328  = typename _Make_integer_sequence<_Tp, _Num>::__type;
329 
330  /// Alias template index_sequence
331  template<size_t... _Idx>
332  using index_sequence = integer_sequence<size_t, _Idx...>;
333 
334  /// Alias template make_index_sequence
335  template<size_t _Num>
337 
338  /// Alias template index_sequence_for
339  template<typename... _Types>
340  using index_sequence_for = make_index_sequence<sizeof...(_Types)>;
341 #endif
342 
343 #if __cplusplus > 201402L
344 
345  struct in_place_t {
346  explicit in_place_t() = default;
347  };
348 
349  inline constexpr in_place_t in_place{};
350 
351  template<typename _Tp> struct in_place_type_t
352  {
353  explicit in_place_type_t() = default;
354  };
355 
356  template<typename _Tp>
357  inline constexpr in_place_type_t<_Tp> in_place_type{};
358 
359  template<size_t _Idx> struct in_place_index_t
360  {
361  explicit in_place_index_t() = default;
362  };
363 
364  template<size_t _Idx>
365  inline constexpr in_place_index_t<_Idx> in_place_index{};
366 
367  template<typename>
368  struct __is_in_place_type_impl : false_type
369  { };
370 
371  template<typename _Tp>
372  struct __is_in_place_type_impl<in_place_type_t<_Tp>> : true_type
373  { };
374 
375  template<typename _Tp>
376  struct __is_in_place_type
377  : public __is_in_place_type_impl<_Tp>
378  { };
379 
380 #define __cpp_lib_as_const 201510
381  template<typename _Tp>
382  constexpr add_const_t<_Tp>& as_const(_Tp& __t) noexcept { return __t; }
383 
384  template<typename _Tp>
385  void as_const(const _Tp&&) = delete;
386 
387 #endif // C++17
388 
389 _GLIBCXX_END_NAMESPACE_VERSION
390 } // namespace
391 
392 #endif
393 
394 #endif /* _GLIBCXX_UTILITY */
_T2 second
first is a copy of the first object
Definition: stl_pair.h:196
constexpr in_place_t in_place
Tag for in-place construction.
Definition: optional:90
ISO C++ entities toplevel namespace is std.
Class template integer_sequence.
Definition: utility:306
make_integer_sequence< size_t, _Num > make_index_sequence
Alias template make_index_sequence.
Definition: utility:336
typename _Make_integer_sequence< _Tp, _Num >::__type make_integer_sequence
Alias template make_integer_sequence.
Definition: utility:328
_Tp exchange(_Tp &__obj, _Up &&__new_val)
Assign __new_val to __obj and return its previous value.
Definition: utility:264
make_index_sequence< sizeof...(_Types)> index_sequence_for
Alias template index_sequence_for.
Definition: utility:340
Struct holding two objects of arbitrary type.
Definition: stl_pair.h:190
tuple_size
Definition: array:328
integral_constant
Definition: type_traits:69
integral_constant< bool, false > false_type
The type used as a compile-time boolean with false value.
Definition: type_traits:90
tuple_element
Definition: array:337
_T1 first
second_type is the second bound type
Definition: stl_pair.h:195