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
78#if __cplusplus > 201402L
79#include <exception>
80#endif
81
82namespace 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 // 2770. tuple_size<const T> specialization is not SFINAE compatible
93
94 template<typename _Tp,
95 typename _Up = typename remove_cv<_Tp>::type,
96 typename = typename enable_if<is_same<_Tp, _Up>::value>::type,
97 size_t = tuple_size<_Tp>::value>
98 using __enable_if_has_tuple_size = _Tp;
99
100 template<typename _Tp>
101 struct tuple_size<const __enable_if_has_tuple_size<_Tp>>
102 : public tuple_size<_Tp> { };
103
104 template<typename _Tp>
105 struct tuple_size<volatile __enable_if_has_tuple_size<_Tp>>
106 : public tuple_size<_Tp> { };
107
108 template<typename _Tp>
109 struct tuple_size<const volatile __enable_if_has_tuple_size<_Tp>>
110 : public tuple_size<_Tp> { };
111
112 /// Gives the type of the ith element of a given tuple type.
113 template<std::size_t __i, typename _Tp>
114 struct tuple_element;
115
116 // Duplicate of C++14's tuple_element_t for internal use in C++11 mode
117 template<std::size_t __i, typename _Tp>
118 using __tuple_element_t = typename tuple_element<__i, _Tp>::type;
119
120 template<std::size_t __i, typename _Tp>
121 struct tuple_element<__i, const _Tp>
122 {
123 typedef typename add_const<__tuple_element_t<__i, _Tp>>::type type;
124 };
125
126 template<std::size_t __i, typename _Tp>
127 struct tuple_element<__i, volatile _Tp>
128 {
129 typedef typename add_volatile<__tuple_element_t<__i, _Tp>>::type type;
130 };
131
132 template<std::size_t __i, typename _Tp>
133 struct tuple_element<__i, const volatile _Tp>
134 {
135 typedef typename add_cv<__tuple_element_t<__i, _Tp>>::type type;
136 };
137
138#if __cplusplus > 201103L
139#define __cpp_lib_tuple_element_t 201402
140
141 template<std::size_t __i, typename _Tp>
142 using tuple_element_t = typename tuple_element<__i, _Tp>::type;
143#endif
144
145 // Various functions which give std::pair a tuple-like interface.
146
147 /// Partial specialization for std::pair
148 template<typename _T1, typename _T2>
149 struct __is_tuple_like_impl<std::pair<_T1, _T2>> : true_type
150 { };
151
152 /// Partial specialization for std::pair
153 template<class _Tp1, class _Tp2>
154 struct tuple_size<std::pair<_Tp1, _Tp2>>
155 : public integral_constant<std::size_t, 2> { };
156
157 /// Partial specialization for std::pair
158 template<class _Tp1, class _Tp2>
159 struct tuple_element<0, std::pair<_Tp1, _Tp2>>
160 { typedef _Tp1 type; };
161
162 /// Partial specialization for std::pair
163 template<class _Tp1, class _Tp2>
164 struct tuple_element<1, std::pair<_Tp1, _Tp2>>
165 { typedef _Tp2 type; };
166
167 template<std::size_t _Int>
168 struct __pair_get;
169
170 template<>
171 struct __pair_get<0>
172 {
173 template<typename _Tp1, typename _Tp2>
174 static constexpr _Tp1&
175 __get(std::pair<_Tp1, _Tp2>& __pair) noexcept
176 { return __pair.first; }
177
178 template<typename _Tp1, typename _Tp2>
179 static constexpr _Tp1&&
180 __move_get(std::pair<_Tp1, _Tp2>&& __pair) noexcept
181 { return std::forward<_Tp1>(__pair.first); }
182
183 template<typename _Tp1, typename _Tp2>
184 static constexpr const _Tp1&
185 __const_get(const std::pair<_Tp1, _Tp2>& __pair) noexcept
186 { return __pair.first; }
187
188 template<typename _Tp1, typename _Tp2>
189 static constexpr const _Tp1&&
190 __const_move_get(const std::pair<_Tp1, _Tp2>&& __pair) noexcept
191 { return std::forward<const _Tp1>(__pair.first); }
192 };
193
194 template<>
195 struct __pair_get<1>
196 {
197 template<typename _Tp1, typename _Tp2>
198 static constexpr _Tp2&
199 __get(std::pair<_Tp1, _Tp2>& __pair) noexcept
200 { return __pair.second; }
201
202 template<typename _Tp1, typename _Tp2>
203 static constexpr _Tp2&&
204 __move_get(std::pair<_Tp1, _Tp2>&& __pair) noexcept
205 { return std::forward<_Tp2>(__pair.second); }
206
207 template<typename _Tp1, typename _Tp2>
208 static constexpr const _Tp2&
209 __const_get(const std::pair<_Tp1, _Tp2>& __pair) noexcept
210 { return __pair.second; }
211
212 template<typename _Tp1, typename _Tp2>
213 static constexpr const _Tp2&&
214 __const_move_get(const std::pair<_Tp1, _Tp2>&& __pair) noexcept
215 { return std::forward<const _Tp2>(__pair.second); }
216 };
217
218 template<std::size_t _Int, class _Tp1, class _Tp2>
219 constexpr typename tuple_element<_Int, std::pair<_Tp1, _Tp2>>::type&
220 get(std::pair<_Tp1, _Tp2>& __in) noexcept
221 { return __pair_get<_Int>::__get(__in); }
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>::__move_get(std::move(__in)); }
227
228 template<std::size_t _Int, class _Tp1, class _Tp2>
229 constexpr const typename tuple_element<_Int, std::pair<_Tp1, _Tp2>>::type&
230 get(const std::pair<_Tp1, _Tp2>& __in) noexcept
231 { return __pair_get<_Int>::__const_get(__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_move_get(std::move(__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 const _Tp&&
259 get(const pair<_Tp, _Up>&& __p) noexcept
260 { return std::move(__p.first); }
261
262 template <typename _Tp, typename _Up>
263 constexpr _Tp&
264 get(pair<_Up, _Tp>& __p) noexcept
265 { return __p.second; }
266
267 template <typename _Tp, typename _Up>
268 constexpr const _Tp&
269 get(const pair<_Up, _Tp>& __p) noexcept
270 { return __p.second; }
271
272 template <typename _Tp, typename _Up>
273 constexpr _Tp&&
274 get(pair<_Up, _Tp>&& __p) noexcept
275 { return std::move(__p.second); }
276
277 template <typename _Tp, typename _Up>
278 constexpr const _Tp&&
279 get(const pair<_Up, _Tp>&& __p) noexcept
280 { return std::move(__p.second); }
281
282#define __cpp_lib_exchange_function 201304
283
284 /// Assign @p __new_val to @p __obj and return its previous value.
285 template <typename _Tp, typename _Up = _Tp>
286 inline _Tp
287 exchange(_Tp& __obj, _Up&& __new_val)
288 { return std::__exchange(__obj, std::forward<_Up>(__new_val)); }
289#endif
290
291 // Stores a tuple of indices. Used by tuple and pair, and by bind() to
292 // extract the elements in a tuple.
293 template<size_t... _Indexes> struct _Index_tuple { };
294
295#ifdef __has_builtin
296# if __has_builtin(__make_integer_seq)
297# define _GLIBCXX_USE_MAKE_INTEGER_SEQ 1
298# endif
299#endif
300
301 // Builds an _Index_tuple<0, 1, 2, ..., _Num-1>.
302 template<size_t _Num>
303 struct _Build_index_tuple
304 {
305#if _GLIBCXX_USE_MAKE_INTEGER_SEQ
306 template<typename, size_t... _Indices>
307 using _IdxTuple = _Index_tuple<_Indices...>;
308
309 using __type = __make_integer_seq<_IdxTuple, size_t, _Num>;
310#else
311 using __type = _Index_tuple<__integer_pack(_Num)...>;
312#endif
313 };
314
315#if __cplusplus > 201103L
316
317#define __cpp_lib_integer_sequence 201304
318
319 /// Class template integer_sequence
320 template<typename _Tp, _Tp... _Idx>
321 struct integer_sequence
322 {
323 typedef _Tp value_type;
324 static constexpr size_t size() noexcept { return sizeof...(_Idx); }
325 };
326
327 /// Alias template make_integer_sequence
328 template<typename _Tp, _Tp _Num>
329 using make_integer_sequence
330#if _GLIBCXX_USE_MAKE_INTEGER_SEQ
331 = __make_integer_seq<integer_sequence, _Tp, _Num>;
332#else
333 = integer_sequence<_Tp, __integer_pack(_Num)...>;
334#endif
335
336#undef _GLIBCXX_USE_MAKE_INTEGER_SEQ
337
338 /// Alias template index_sequence
339 template<size_t... _Idx>
340 using index_sequence = integer_sequence<size_t, _Idx...>;
341
342 /// Alias template make_index_sequence
343 template<size_t _Num>
344 using make_index_sequence = make_integer_sequence<size_t, _Num>;
345
346 /// Alias template index_sequence_for
347 template<typename... _Types>
348 using index_sequence_for = make_index_sequence<sizeof...(_Types)>;
349#endif
350
351#if __cplusplus > 201402L
352
353 struct in_place_t {
354 explicit in_place_t() = default;
355 };
356
357 inline constexpr in_place_t in_place{};
358
359 template<typename _Tp> struct in_place_type_t
360 {
361 explicit in_place_type_t() = default;
362 };
363
364 template<typename _Tp>
365 inline constexpr in_place_type_t<_Tp> in_place_type{};
366
367 template<size_t _Idx> struct in_place_index_t
368 {
369 explicit in_place_index_t() = default;
370 };
371
372 template<size_t _Idx>
373 inline constexpr in_place_index_t<_Idx> in_place_index{};
374
375 template<typename>
376 struct __is_in_place_type_impl : false_type
377 { };
378
379 template<typename _Tp>
380 struct __is_in_place_type_impl<in_place_type_t<_Tp>> : true_type
381 { };
382
383 template<typename _Tp>
384 struct __is_in_place_type
385 : public __is_in_place_type_impl<_Tp>
386 { };
387
388#define __cpp_lib_as_const 201510
389 template<typename _Tp>
390 constexpr add_const_t<_Tp>& as_const(_Tp& __t) noexcept { return __t; }
391
392 template<typename _Tp>
393 void as_const(const _Tp&&) = delete;
394
395#endif // C++17
396
397_GLIBCXX_END_NAMESPACE_VERSION
398} // namespace
399
400#endif
401
402#endif /* _GLIBCXX_UTILITY */
403