1// <utility> -*- C++ -*-
2
3// Copyright (C) 2001-2018 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
78namespace 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 // 2770. tuple_size<const T> specialization is not SFINAE compatible
89
90 template<typename _Tp,
91 typename _Up = typename remove_cv<_Tp>::type,
92 typename = typename enable_if<is_same<_Tp, _Up>::value>::type,
93 size_t = tuple_size<_Tp>::value>
94 using __enable_if_has_tuple_size = _Tp;
95
96 template<typename _Tp>
97 struct tuple_size<const __enable_if_has_tuple_size<_Tp>>
98 : public tuple_size<_Tp> { };
99
100 template<typename _Tp>
101 struct tuple_size<volatile __enable_if_has_tuple_size<_Tp>>
102 : public tuple_size<_Tp> { };
103
104 template<typename _Tp>
105 struct tuple_size<const volatile __enable_if_has_tuple_size<_Tp>>
106 : public tuple_size<_Tp> { };
107
108 /// Gives the type of the ith element of a given tuple type.
109 template<std::size_t __i, typename _Tp>
110 struct tuple_element;
111
112 // Duplicate of C++14's tuple_element_t for internal use in C++11 mode
113 template<std::size_t __i, typename _Tp>
114 using __tuple_element_t = typename tuple_element<__i, _Tp>::type;
115
116 template<std::size_t __i, typename _Tp>
117 struct tuple_element<__i, const _Tp>
118 {
119 typedef typename add_const<__tuple_element_t<__i, _Tp>>::type type;
120 };
121
122 template<std::size_t __i, typename _Tp>
123 struct tuple_element<__i, volatile _Tp>
124 {
125 typedef typename add_volatile<__tuple_element_t<__i, _Tp>>::type type;
126 };
127
128 template<std::size_t __i, typename _Tp>
129 struct tuple_element<__i, const volatile _Tp>
130 {
131 typedef typename add_cv<__tuple_element_t<__i, _Tp>>::type type;
132 };
133
134#if __cplusplus > 201103L
135#define __cpp_lib_tuple_element_t 201402
136
137 template<std::size_t __i, typename _Tp>
138 using tuple_element_t = typename tuple_element<__i, _Tp>::type;
139#endif
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 template<typename _Tp1, typename _Tp2>
185 static constexpr const _Tp1&&
186 __const_move_get(const std::pair<_Tp1, _Tp2>&& __pair) noexcept
187 { return std::forward<const _Tp1>(__pair.first); }
188 };
189
190 template<>
191 struct __pair_get<1>
192 {
193 template<typename _Tp1, typename _Tp2>
194 static constexpr _Tp2&
195 __get(std::pair<_Tp1, _Tp2>& __pair) noexcept
196 { return __pair.second; }
197
198 template<typename _Tp1, typename _Tp2>
199 static constexpr _Tp2&&
200 __move_get(std::pair<_Tp1, _Tp2>&& __pair) noexcept
201 { return std::forward<_Tp2>(__pair.second); }
202
203 template<typename _Tp1, typename _Tp2>
204 static constexpr const _Tp2&
205 __const_get(const std::pair<_Tp1, _Tp2>& __pair) noexcept
206 { return __pair.second; }
207
208 template<typename _Tp1, typename _Tp2>
209 static constexpr const _Tp2&&
210 __const_move_get(const std::pair<_Tp1, _Tp2>&& __pair) noexcept
211 { return std::forward<const _Tp2>(__pair.second); }
212 };
213
214 template<std::size_t _Int, class _Tp1, class _Tp2>
215 constexpr typename tuple_element<_Int, std::pair<_Tp1, _Tp2>>::type&
216 get(std::pair<_Tp1, _Tp2>& __in) noexcept
217 { return __pair_get<_Int>::__get(__in); }
218
219 template<std::size_t _Int, class _Tp1, class _Tp2>
220 constexpr typename tuple_element<_Int, std::pair<_Tp1, _Tp2>>::type&&
221 get(std::pair<_Tp1, _Tp2>&& __in) noexcept
222 { return __pair_get<_Int>::__move_get(std::move(__in)); }
223
224 template<std::size_t _Int, class _Tp1, class _Tp2>
225 constexpr const typename tuple_element<_Int, std::pair<_Tp1, _Tp2>>::type&
226 get(const std::pair<_Tp1, _Tp2>& __in) noexcept
227 { return __pair_get<_Int>::__const_get(__in); }
228
229 template<std::size_t _Int, class _Tp1, class _Tp2>
230 constexpr const typename tuple_element<_Int, std::pair<_Tp1, _Tp2>>::type&&
231 get(const std::pair<_Tp1, _Tp2>&& __in) noexcept
232 { return __pair_get<_Int>::__const_move_get(std::move(__in)); }
233
234#if __cplusplus > 201103L
235
236#define __cpp_lib_tuples_by_type 201304
237
238 template <typename _Tp, typename _Up>
239 constexpr _Tp&
240 get(pair<_Tp, _Up>& __p) noexcept
241 { return __p.first; }
242
243 template <typename _Tp, typename _Up>
244 constexpr const _Tp&
245 get(const pair<_Tp, _Up>& __p) noexcept
246 { return __p.first; }
247
248 template <typename _Tp, typename _Up>
249 constexpr _Tp&&
250 get(pair<_Tp, _Up>&& __p) noexcept
251 { return std::move(__p.first); }
252
253 template <typename _Tp, typename _Up>
254 constexpr const _Tp&&
255 get(const pair<_Tp, _Up>&& __p) noexcept
256 { return std::move(__p.first); }
257
258 template <typename _Tp, typename _Up>
259 constexpr _Tp&
260 get(pair<_Up, _Tp>& __p) noexcept
261 { return __p.second; }
262
263 template <typename _Tp, typename _Up>
264 constexpr const _Tp&
265 get(const pair<_Up, _Tp>& __p) noexcept
266 { return __p.second; }
267
268 template <typename _Tp, typename _Up>
269 constexpr _Tp&&
270 get(pair<_Up, _Tp>&& __p) noexcept
271 { return std::move(__p.second); }
272
273 template <typename _Tp, typename _Up>
274 constexpr const _Tp&&
275 get(const pair<_Up, _Tp>&& __p) noexcept
276 { return std::move(__p.second); }
277
278#define __cpp_lib_exchange_function 201304
279
280 /// Assign @p __new_val to @p __obj and return its previous value.
281 template <typename _Tp, typename _Up = _Tp>
282 inline _Tp
283 exchange(_Tp& __obj, _Up&& __new_val)
284 { return std::__exchange(__obj, std::forward<_Up>(__new_val)); }
285#endif
286
287 // Stores a tuple of indices. Used by tuple and pair, and by bind() to
288 // extract the elements in a tuple.
289 template<size_t... _Indexes> struct _Index_tuple { };
290
291#ifdef __has_builtin
292# if __has_builtin(__make_integer_seq)
293# define _GLIBCXX_USE_MAKE_INTEGER_SEQ 1
294# endif
295#endif
296
297 // Builds an _Index_tuple<0, 1, 2, ..., _Num-1>.
298 template<size_t _Num>
299 struct _Build_index_tuple
300 {
301#if _GLIBCXX_USE_MAKE_INTEGER_SEQ
302 template<typename, size_t... _Indices>
303 using _IdxTuple = _Index_tuple<_Indices...>;
304
305 using __type = __make_integer_seq<_IdxTuple, size_t, _Num>;
306#else
307 using __type = _Index_tuple<__integer_pack(_Num)...>;
308#endif
309 };
310
311#if __cplusplus > 201103L
312
313#define __cpp_lib_integer_sequence 201304
314
315 /// Class template integer_sequence
316 template<typename _Tp, _Tp... _Idx>
317 struct integer_sequence
318 {
319 typedef _Tp value_type;
320 static constexpr size_t size() noexcept { return sizeof...(_Idx); }
321 };
322
323 /// Alias template make_integer_sequence
324 template<typename _Tp, _Tp _Num>
325 using make_integer_sequence
326#if _GLIBCXX_USE_MAKE_INTEGER_SEQ
327 = __make_integer_seq<integer_sequence, _Tp, _Num>;
328#else
329 = integer_sequence<_Tp, __integer_pack(_Num)...>;
330#endif
331
332#undef _GLIBCXX_USE_MAKE_INTEGER_SEQ
333
334 /// Alias template index_sequence
335 template<size_t... _Idx>
336 using index_sequence = integer_sequence<size_t, _Idx...>;
337
338 /// Alias template make_index_sequence
339 template<size_t _Num>
340 using make_index_sequence = make_integer_sequence<size_t, _Num>;
341
342 /// Alias template index_sequence_for
343 template<typename... _Types>
344 using index_sequence_for = make_index_sequence<sizeof...(_Types)>;
345#endif
346
347#if __cplusplus > 201402L
348
349 struct in_place_t {
350 explicit in_place_t() = default;
351 };
352
353 inline constexpr in_place_t in_place{};
354
355 template<typename _Tp> struct in_place_type_t
356 {
357 explicit in_place_type_t() = default;
358 };
359
360 template<typename _Tp>
361 inline constexpr in_place_type_t<_Tp> in_place_type{};
362
363 template<size_t _Idx> struct in_place_index_t
364 {
365 explicit in_place_index_t() = default;
366 };
367
368 template<size_t _Idx>
369 inline constexpr in_place_index_t<_Idx> in_place_index{};
370
371 template<typename>
372 struct __is_in_place_type_impl : false_type
373 { };
374
375 template<typename _Tp>
376 struct __is_in_place_type_impl<in_place_type_t<_Tp>> : true_type
377 { };
378
379 template<typename _Tp>
380 struct __is_in_place_type
381 : public __is_in_place_type_impl<_Tp>
382 { };
383
384#define __cpp_lib_as_const 201510
385 template<typename _Tp>
386 constexpr add_const_t<_Tp>& as_const(_Tp& __t) noexcept { return __t; }
387
388 template<typename _Tp>
389 void as_const(const _Tp&&) = delete;
390
391#endif // C++17
392
393_GLIBCXX_END_NAMESPACE_VERSION
394} // namespace
395
396#endif
397
398#endif /* _GLIBCXX_UTILITY */
399