1// <utility> -*- C++ -*- 
2 
3// Copyright (C) 2001-2019 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 >= 201402L 
135// The standard says this macro and alias template should be in <tuple> 
136// but we define them here, to be available when the partial specializations 
137// of tuple_element<pair<T,U>> and tuple_element<array<T,N>> are defined. 
138#define __cpp_lib_tuple_element_t 201402L 
139 
140 template<std::size_t __i, typename _Tp> 
141 using tuple_element_t = typename tuple_element<__i, _Tp>::type; 
142#endif 
143 
144 // Various functions which give std::pair a tuple-like interface. 
145 
146 /// Partial specialization for std::pair 
147 template<typename _T1, typename _T2> 
148 struct __is_tuple_like_impl<std::pair<_T1, _T2>> : true_type 
149 { }; 
150 
151 /// Partial specialization for std::pair 
152 template<class _Tp1, class _Tp2> 
153 struct tuple_size<std::pair<_Tp1, _Tp2>> 
154 : public integral_constant<std::size_t, 2> { }; 
155 
156 /// Partial specialization for std::pair 
157 template<class _Tp1, class _Tp2> 
158 struct tuple_element<0, std::pair<_Tp1, _Tp2>> 
159 { typedef _Tp1 type; }; 
160 
161 /// Partial specialization for std::pair 
162 template<class _Tp1, class _Tp2> 
163 struct tuple_element<1, std::pair<_Tp1, _Tp2>> 
164 { typedef _Tp2 type; }; 
165 
166 template<std::size_t _Int> 
167 struct __pair_get; 
168 
169 template<> 
170 struct __pair_get<0> 
171 { 
172 template<typename _Tp1, typename _Tp2> 
173 static constexpr _Tp1& 
174 __get(std::pair<_Tp1, _Tp2>& __pair) noexcept 
175 { return __pair.first; } 
176 
177 template<typename _Tp1, typename _Tp2> 
178 static constexpr _Tp1&& 
179 __move_get(std::pair<_Tp1, _Tp2>&& __pair) noexcept 
180 { return std::forward<_Tp1>(__pair.first); } 
181 
182 template<typename _Tp1, typename _Tp2> 
183 static constexpr const _Tp1& 
184 __const_get(const std::pair<_Tp1, _Tp2>& __pair) noexcept 
185 { return __pair.first; } 
186 
187 template<typename _Tp1, typename _Tp2> 
188 static constexpr const _Tp1&& 
189 __const_move_get(const std::pair<_Tp1, _Tp2>&& __pair) noexcept 
190 { return std::forward<const _Tp1>(__pair.first); } 
191 }; 
192 
193 template<> 
194 struct __pair_get<1> 
195 { 
196 template<typename _Tp1, typename _Tp2> 
197 static constexpr _Tp2& 
198 __get(std::pair<_Tp1, _Tp2>& __pair) noexcept 
199 { return __pair.second; } 
200 
201 template<typename _Tp1, typename _Tp2> 
202 static constexpr _Tp2&& 
203 __move_get(std::pair<_Tp1, _Tp2>&& __pair) noexcept 
204 { return std::forward<_Tp2>(__pair.second); } 
205 
206 template<typename _Tp1, typename _Tp2> 
207 static constexpr const _Tp2& 
208 __const_get(const std::pair<_Tp1, _Tp2>& __pair) noexcept 
209 { return __pair.second; } 
210 
211 template<typename _Tp1, typename _Tp2> 
212 static constexpr const _Tp2&& 
213 __const_move_get(const std::pair<_Tp1, _Tp2>&& __pair) noexcept 
214 { return std::forward<const _Tp2>(__pair.second); } 
215 }; 
216 
217 template<std::size_t _Int, class _Tp1, class _Tp2> 
218 constexpr typename tuple_element<_Int, std::pair<_Tp1, _Tp2>>::type& 
219 get(std::pair<_Tp1, _Tp2>& __in) noexcept 
220 { return __pair_get<_Int>::__get(__in); } 
221 
222 template<std::size_t _Int, class _Tp1, class _Tp2> 
223 constexpr typename tuple_element<_Int, std::pair<_Tp1, _Tp2>>::type&& 
224 get(std::pair<_Tp1, _Tp2>&& __in) noexcept 
225 { return __pair_get<_Int>::__move_get(std::move(__in)); } 
226 
227 template<std::size_t _Int, class _Tp1, class _Tp2> 
228 constexpr const typename tuple_element<_Int, std::pair<_Tp1, _Tp2>>::type& 
229 get(const std::pair<_Tp1, _Tp2>& __in) noexcept 
230 { return __pair_get<_Int>::__const_get(__in); } 
231 
232 template<std::size_t _Int, class _Tp1, class _Tp2> 
233 constexpr const typename tuple_element<_Int, std::pair<_Tp1, _Tp2>>::type&& 
234 get(const std::pair<_Tp1, _Tp2>&& __in) noexcept 
235 { return __pair_get<_Int>::__const_move_get(std::move(__in)); } 
236 
237#if __cplusplus > 201103L 
238 
239#define __cpp_lib_tuples_by_type 201304 
240 
241 template <typename _Tp, typename _Up> 
242 constexpr _Tp& 
243 get(pair<_Tp, _Up>& __p) noexcept 
244 { return __p.first; } 
245 
246 template <typename _Tp, typename _Up> 
247 constexpr const _Tp& 
248 get(const pair<_Tp, _Up>& __p) noexcept 
249 { return __p.first; } 
250 
251 template <typename _Tp, typename _Up> 
252 constexpr _Tp&& 
253 get(pair<_Tp, _Up>&& __p) noexcept 
254 { return std::move(__p.first); } 
255 
256 template <typename _Tp, typename _Up> 
257 constexpr const _Tp&& 
258 get(const pair<_Tp, _Up>&& __p) noexcept 
259 { return std::move(__p.first); } 
260 
261 template <typename _Tp, typename _Up> 
262 constexpr _Tp& 
263 get(pair<_Up, _Tp>& __p) noexcept 
264 { return __p.second; } 
265 
266 template <typename _Tp, typename _Up> 
267 constexpr const _Tp& 
268 get(const pair<_Up, _Tp>& __p) noexcept 
269 { return __p.second; } 
270 
271 template <typename _Tp, typename _Up> 
272 constexpr _Tp&& 
273 get(pair<_Up, _Tp>&& __p) noexcept 
274 { return std::move(__p.second); } 
275 
276 template <typename _Tp, typename _Up> 
277 constexpr const _Tp&& 
278 get(const pair<_Up, _Tp>&& __p) noexcept 
279 { return std::move(__p.second); } 
280 
281#define __cpp_lib_exchange_function 201304 
282 
283 /// Assign @p __new_val to @p __obj and return its previous value. 
284 template <typename _Tp, typename _Up = _Tp> 
285 inline _Tp 
286 exchange(_Tp& __obj, _Up&& __new_val) 
287 { return std::__exchange(__obj, std::forward<_Up>(__new_val)); } 
288#endif 
289 
290 // Stores a tuple of indices. Used by tuple and pair, and by bind() to 
291 // extract the elements in a tuple. 
292 template<size_t... _Indexes> struct _Index_tuple { }; 
293 
294#ifdef __has_builtin 
295# if __has_builtin(__make_integer_seq) 
296# define _GLIBCXX_USE_MAKE_INTEGER_SEQ 1 
297# endif 
298#endif 
299 
300 // Builds an _Index_tuple<0, 1, 2, ..., _Num-1>. 
301 template<size_t _Num> 
302 struct _Build_index_tuple 
303 { 
304#if _GLIBCXX_USE_MAKE_INTEGER_SEQ 
305 template<typename, size_t... _Indices> 
306 using _IdxTuple = _Index_tuple<_Indices...>; 
307 
308 using __type = __make_integer_seq<_IdxTuple, size_t, _Num>; 
309#else 
310 using __type = _Index_tuple<__integer_pack(_Num)...>; 
311#endif 
312 }; 
313 
314#if __cplusplus > 201103L 
315 
316#define __cpp_lib_integer_sequence 201304 
317 
318 /// Class template integer_sequence 
319 template<typename _Tp, _Tp... _Idx> 
320 struct integer_sequence 
321 { 
322 typedef _Tp value_type; 
323 static constexpr size_t size() noexcept { return sizeof...(_Idx); } 
324 }; 
325 
326 /// Alias template make_integer_sequence 
327 template<typename _Tp, _Tp _Num> 
328 using make_integer_sequence 
329#if _GLIBCXX_USE_MAKE_INTEGER_SEQ 
330 = __make_integer_seq<integer_sequence, _Tp, _Num>; 
331#else 
332 = integer_sequence<_Tp, __integer_pack(_Num)...>; 
333#endif 
334 
335#undef _GLIBCXX_USE_MAKE_INTEGER_SEQ 
336 
337 /// Alias template index_sequence 
338 template<size_t... _Idx> 
339 using index_sequence = integer_sequence<size_t, _Idx...>; 
340 
341 /// Alias template make_index_sequence 
342 template<size_t _Num> 
343 using make_index_sequence = make_integer_sequence<size_t, _Num>; 
344 
345 /// Alias template index_sequence_for 
346 template<typename... _Types> 
347 using index_sequence_for = make_index_sequence<sizeof...(_Types)>; 
348#endif 
349 
350#if __cplusplus > 201402L 
351 
352 struct in_place_t { 
353 explicit in_place_t() = default; 
354 }; 
355 
356 inline constexpr in_place_t in_place{}; 
357 
358 template<typename _Tp> struct in_place_type_t 
359 { 
360 explicit in_place_type_t() = default; 
361 }; 
362 
363 template<typename _Tp> 
364 inline constexpr in_place_type_t<_Tp> in_place_type{}; 
365 
366 template<size_t _Idx> struct in_place_index_t 
367 { 
368 explicit in_place_index_t() = default; 
369 }; 
370 
371 template<size_t _Idx> 
372 inline constexpr in_place_index_t<_Idx> in_place_index{}; 
373 
374 template<typename> 
375 struct __is_in_place_type_impl : false_type 
376 { }; 
377 
378 template<typename _Tp> 
379 struct __is_in_place_type_impl<in_place_type_t<_Tp>> : true_type 
380 { }; 
381 
382 template<typename _Tp> 
383 struct __is_in_place_type 
384 : public __is_in_place_type_impl<_Tp> 
385 { }; 
386 
387#define __cpp_lib_as_const 201510 
388 template<typename _Tp> 
389 constexpr add_const_t<_Tp>& as_const(_Tp& __t) noexcept { return __t; } 
390 
391 template<typename _Tp> 
392 void as_const(const _Tp&&) = delete; 
393 
394#endif // C++17 
395 
396_GLIBCXX_END_NAMESPACE_VERSION 
397} // namespace 
398 
399#endif 
400 
401#endif /* _GLIBCXX_UTILITY */ 
402