Line data Source code
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 : namespace 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&
190 411 : __get(std::pair<_Tp1, _Tp2>& __pair) noexcept
191 411 : { 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 2942 : __const_get(const std::pair<_Tp1, _Tp2>& __pair) noexcept
201 2942 : { 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&
225 411 : get(std::pair<_Tp1, _Tp2>& __in) noexcept
226 411 : { 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 2942 : get(const std::pair<_Tp1, _Tp2>& __in) noexcept
236 2942 : { 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 */
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