1// <utility> -*- C++ -*-
2
3// Copyright (C) 2001-2017 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 // 2770. tuple_size<const T> specialization is not SFINAE compatible
88
89#if __cplusplus <= 201402L
90 template<typename _Tp, typename = void>
91 struct __tuple_size_cv_impl { };
92
93 template<typename _Tp>
94 struct __tuple_size_cv_impl<_Tp, __void_t<decltype(tuple_size<_Tp>::value)>>
95 : integral_constant<size_t, tuple_size<_Tp>::value> { };
96
97 // _GLIBCXX_RESOLVE_LIB_DEFECTS
98 // 2313. tuple_size should always derive from integral_constant<size_t, N>
99 template<typename _Tp>
100 struct tuple_size<const _Tp> : __tuple_size_cv_impl<_Tp> { };
101
102 template<typename _Tp>
103 struct tuple_size<volatile _Tp> : __tuple_size_cv_impl<_Tp> { };
104
105 template<typename _Tp>
106 struct tuple_size<const volatile _Tp> : __tuple_size_cv_impl<_Tp> { };
107#else
108 template<typename _Tp,
109 typename _Up = typename remove_cv<_Tp>::type,
110 typename = typename enable_if<is_same<_Tp, _Up>::value>::type,
111 size_t = tuple_size<_Tp>::value>
112 using __enable_if_has_tuple_size = _Tp;
113
114 template<typename _Tp>
115 struct tuple_size<const __enable_if_has_tuple_size<_Tp>>
116 : public tuple_size<_Tp> { };
117
118 template<typename _Tp>
119 struct tuple_size<volatile __enable_if_has_tuple_size<_Tp>>
120 : public tuple_size<_Tp> { };
121
122 template<typename _Tp>
123 struct tuple_size<const volatile __enable_if_has_tuple_size<_Tp>>
124 : public tuple_size<_Tp> { };
125#endif
126
127 /// Gives the type of the ith element of a given tuple type.
128 template<std::size_t __i, typename _Tp>
129 struct tuple_element;
130
131 // Duplicate of C++14's tuple_element_t for internal use in C++11 mode
132 template<std::size_t __i, typename _Tp>
133 using __tuple_element_t = typename tuple_element<__i, _Tp>::type;
134
135 template<std::size_t __i, typename _Tp>
136 struct tuple_element<__i, const _Tp>
137 {
138 typedef typename add_const<__tuple_element_t<__i, _Tp>>::type type;
139 };
140
141 template<std::size_t __i, typename _Tp>
142 struct tuple_element<__i, volatile _Tp>
143 {
144 typedef typename add_volatile<__tuple_element_t<__i, _Tp>>::type type;
145 };
146
147 template<std::size_t __i, typename _Tp>
148 struct tuple_element<__i, const volatile _Tp>
149 {
150 typedef typename add_cv<__tuple_element_t<__i, _Tp>>::type type;
151 };
152
153#if __cplusplus > 201103L
154#define __cpp_lib_tuple_element_t 201402
155
156 template<std::size_t __i, typename _Tp>
157 using tuple_element_t = typename tuple_element<__i, _Tp>::type;
158#endif
159
160 // Various functions which give std::pair a tuple-like interface.
161
162 /// Partial specialization for std::pair
163 template<typename _T1, typename _T2>
164 struct __is_tuple_like_impl<std::pair<_T1, _T2>> : true_type
165 { };
166
167 /// Partial specialization for std::pair
168 template<class _Tp1, class _Tp2>
169 struct tuple_size<std::pair<_Tp1, _Tp2>>
170 : public integral_constant<std::size_t, 2> { };
171
172 /// Partial specialization for std::pair
173 template<class _Tp1, class _Tp2>
174 struct tuple_element<0, std::pair<_Tp1, _Tp2>>
175 { typedef _Tp1 type; };
176
177 /// Partial specialization for std::pair
178 template<class _Tp1, class _Tp2>
179 struct tuple_element<1, std::pair<_Tp1, _Tp2>>
180 { typedef _Tp2 type; };
181
182 template<std::size_t _Int>
183 struct __pair_get;
184
185 template<>
186 struct __pair_get<0>
187 {
188 template<typename _Tp1, typename _Tp2>
189 static constexpr _Tp1&
190 __get(std::pair<_Tp1, _Tp2>& __pair) noexcept
191 { return __pair.first; }
192
193 template<typename _Tp1, typename _Tp2>
194 static constexpr _Tp1&&
195 __move_get(std::pair<_Tp1, _Tp2>&& __pair) noexcept
196 { return std::forward<_Tp1>(__pair.first); }
197
198 template<typename _Tp1, typename _Tp2>
199 static constexpr const _Tp1&
200 __const_get(const std::pair<_Tp1, _Tp2>& __pair) noexcept
201 { return __pair.first; }
202 };
203
204 template<>
205 struct __pair_get<1>
206 {
207 template<typename _Tp1, typename _Tp2>
208 static constexpr _Tp2&
209 __get(std::pair<_Tp1, _Tp2>& __pair) noexcept
210 { return __pair.second; }
211
212 template<typename _Tp1, typename _Tp2>
213 static constexpr _Tp2&&
214 __move_get(std::pair<_Tp1, _Tp2>&& __pair) noexcept
215 { return std::forward<_Tp2>(__pair.second); }
216
217 template<typename _Tp1, typename _Tp2>
218 static constexpr const _Tp2&
219 __const_get(const std::pair<_Tp1, _Tp2>& __pair) noexcept
220 { return __pair.second; }
221 };
222
223 template<std::size_t _Int, class _Tp1, class _Tp2>
224 constexpr typename tuple_element<_Int, std::pair<_Tp1, _Tp2>>::type&
225 get(std::pair<_Tp1, _Tp2>& __in) noexcept
226 { return __pair_get<_Int>::__get(__in); }
227
228 template<std::size_t _Int, class _Tp1, class _Tp2>
229 constexpr typename tuple_element<_Int, std::pair<_Tp1, _Tp2>>::type&&
230 get(std::pair<_Tp1, _Tp2>&& __in) noexcept
231 { return __pair_get<_Int>::__move_get(std::move(__in)); }
232
233 template<std::size_t _Int, class _Tp1, class _Tp2>
234 constexpr const typename tuple_element<_Int, std::pair<_Tp1, _Tp2>>::type&
235 get(const std::pair<_Tp1, _Tp2>& __in) noexcept
236 { return __pair_get<_Int>::__const_get(__in); }
237
238#if __cplusplus > 201103L
239
240#define __cpp_lib_tuples_by_type 201304
241
242 template <typename _Tp, typename _Up>
243 constexpr _Tp&
244 get(pair<_Tp, _Up>& __p) noexcept
245 { return __p.first; }
246
247 template <typename _Tp, typename _Up>
248 constexpr const _Tp&
249 get(const pair<_Tp, _Up>& __p) noexcept
250 { return __p.first; }
251
252 template <typename _Tp, typename _Up>
253 constexpr _Tp&&
254 get(pair<_Tp, _Up>&& __p) noexcept
255 { return std::move(__p.first); }
256
257 template <typename _Tp, typename _Up>
258 constexpr _Tp&
259 get(pair<_Up, _Tp>& __p) noexcept
260 { return __p.second; }
261
262 template <typename _Tp, typename _Up>
263 constexpr const _Tp&
264 get(const pair<_Up, _Tp>& __p) noexcept
265 { return __p.second; }
266
267 template <typename _Tp, typename _Up>
268 constexpr _Tp&&
269 get(pair<_Up, _Tp>&& __p) noexcept
270 { return std::move(__p.second); }
271
272#define __cpp_lib_exchange_function 201304
273
274 /// Assign @p __new_val to @p __obj and return its previous value.
275 template <typename _Tp, typename _Up = _Tp>
276 inline _Tp
277 exchange(_Tp& __obj, _Up&& __new_val)
278 { return std::__exchange(__obj, std::forward<_Up>(__new_val)); }
279#endif
280
281 // Stores a tuple of indices. Used by tuple and pair, and by bind() to
282 // extract the elements in a tuple.
283 template<size_t... _Indexes> struct _Index_tuple { };
284
285 // Concatenates two _Index_tuples.
286 template<typename _Itup1, typename _Itup2> struct _Itup_cat;
287
288 template<size_t... _Ind1, size_t... _Ind2>
289 struct _Itup_cat<_Index_tuple<_Ind1...>, _Index_tuple<_Ind2...>>
290 {
291 using __type = _Index_tuple<_Ind1..., (_Ind2 + sizeof...(_Ind1))...>;
292 };
293
294 // Builds an _Index_tuple<0, 1, 2, ..., _Num-1>.
295 template<size_t _Num>
296 struct _Build_index_tuple
297 : _Itup_cat<typename _Build_index_tuple<_Num / 2>::__type,
298 typename _Build_index_tuple<_Num - _Num / 2>::__type>
299 { };
300
301 template<>
302 struct _Build_index_tuple<1>
303 {
304 typedef _Index_tuple<0> __type;
305 };
306
307 template<>
308 struct _Build_index_tuple<0>
309 {
310 typedef _Index_tuple<> __type;
311 };
312
313#if __cplusplus > 201103L
314
315#define __cpp_lib_integer_sequence 201304
316
317 /// Class template integer_sequence
318 template<typename _Tp, _Tp... _Idx>
319 struct integer_sequence
320 {
321 typedef _Tp value_type;
322 static constexpr size_t size() noexcept { return sizeof...(_Idx); }
323 };
324
325 template<typename _Tp, _Tp _Num,
326 typename _ISeq = typename _Build_index_tuple<_Num>::__type>
327 struct _Make_integer_sequence;
328
329 template<typename _Tp, _Tp _Num, size_t... _Idx>
330 struct _Make_integer_sequence<_Tp, _Num, _Index_tuple<_Idx...>>
331 {
332 static_assert( _Num >= 0,
333 "Cannot make integer sequence of negative length" );
334
335 typedef integer_sequence<_Tp, static_cast<_Tp>(_Idx)...> __type;
336 };
337
338 /// Alias template make_integer_sequence
339 template<typename _Tp, _Tp _Num>
340 using make_integer_sequence
341 = typename _Make_integer_sequence<_Tp, _Num>::__type;
342
343 /// Alias template index_sequence
344 template<size_t... _Idx>
345 using index_sequence = integer_sequence<size_t, _Idx...>;
346
347 /// Alias template make_index_sequence
348 template<size_t _Num>
349 using make_index_sequence = make_integer_sequence<size_t, _Num>;
350
351 /// Alias template index_sequence_for
352 template<typename... _Types>
353 using index_sequence_for = make_index_sequence<sizeof...(_Types)>;
354#endif
355
356#if __cplusplus > 201402L
357
358 struct in_place_t {
359 explicit in_place_t() = default;
360 };
361
362 inline constexpr in_place_t in_place{};
363
364 template<typename _Tp> struct in_place_type_t
365 {
366 explicit in_place_type_t() = default;
367 };
368
369 template<typename _Tp>
370 inline constexpr in_place_type_t<_Tp> in_place_type{};
371
372 template<size_t _Idx> struct in_place_index_t
373 {
374 explicit in_place_index_t() = default;
375 };
376
377 template<size_t _Idx>
378 inline constexpr in_place_index_t<_Idx> in_place_index{};
379
380 template<typename>
381 struct __is_in_place_type_impl : false_type
382 { };
383
384 template<typename _Tp>
385 struct __is_in_place_type_impl<in_place_type_t<_Tp>> : true_type
386 { };
387
388 template<typename _Tp>
389 struct __is_in_place_type
390 : public __is_in_place_type_impl<_Tp>
391 { };
392
393#define __cpp_lib_as_const 201510
394 template<typename _Tp>
395 constexpr add_const_t<_Tp>& as_const(_Tp& __t) noexcept { return __t; }
396
397 template<typename _Tp>
398 void as_const(const _Tp&&) = delete;
399
400#endif // C++17
401
402_GLIBCXX_END_NAMESPACE_VERSION
403} // namespace
404
405#endif
406
407#endif /* _GLIBCXX_UTILITY */
408