1// <utility> -*- C++ -*- 
2 
3// Copyright (C) 2001-2021 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 > 201703L 
79#include <ext/numeric_traits.h> 
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<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<size_t __i, typename _Tp> 
118 using __tuple_element_t = typename tuple_element<__i, _Tp>::type; 
119 
120 template<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<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<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 >= 201402L 
139// The standard says this macro and alias template should be in <tuple> 
140// but we define them here, to be available when the partial specializations 
141// of tuple_element<pair<T,U>> and tuple_element<array<T,N>> are defined. 
142#define __cpp_lib_tuple_element_t 201402L 
143 
144 template<size_t __i, typename _Tp> 
145 using tuple_element_t = typename tuple_element<__i, _Tp>::type; 
146#endif 
147 
148 // Various functions which give std::pair a tuple-like interface. 
149 
150 /// Partial specialization for std::pair 
151 template<typename _T1, typename _T2> 
152 struct __is_tuple_like_impl<pair<_T1, _T2>> : true_type 
153 { }; 
154 
155 /// Partial specialization for std::pair 
156 template<class _Tp1, class _Tp2> 
157 struct tuple_size<pair<_Tp1, _Tp2>> 
158 : public integral_constant<size_t, 2> { }; 
159 
160 /// Partial specialization for std::pair 
161 template<class _Tp1, class _Tp2> 
162 struct tuple_element<0, pair<_Tp1, _Tp2>> 
163 { typedef _Tp1 type; }; 
164 
165 /// Partial specialization for std::pair 
166 template<class _Tp1, class _Tp2> 
167 struct tuple_element<1, pair<_Tp1, _Tp2>> 
168 { typedef _Tp2 type; }; 
169 
170 template<size_t _Int> 
171 struct __pair_get; 
172 
173 template<> 
174 struct __pair_get<0> 
175 { 
176 template<typename _Tp1, typename _Tp2> 
177 static constexpr _Tp1& 
178 __get(pair<_Tp1, _Tp2>& __pair) noexcept 
179 { return __pair.first; } 
180 
181 template<typename _Tp1, typename _Tp2> 
182 static constexpr _Tp1&& 
183 __move_get(pair<_Tp1, _Tp2>&& __pair) noexcept 
184 { return std::forward<_Tp1>(__pair.first); } 
185 
186 template<typename _Tp1, typename _Tp2> 
187 static constexpr const _Tp1& 
188 __const_get(const pair<_Tp1, _Tp2>& __pair) noexcept 
189 { return __pair.first; } 
190 
191 template<typename _Tp1, typename _Tp2> 
192 static constexpr const _Tp1&& 
193 __const_move_get(const pair<_Tp1, _Tp2>&& __pair) noexcept 
194 { return std::forward<const _Tp1>(__pair.first); } 
195 }; 
196 
197 template<> 
198 struct __pair_get<1> 
199 { 
200 template<typename _Tp1, typename _Tp2> 
201 static constexpr _Tp2& 
202 __get(pair<_Tp1, _Tp2>& __pair) noexcept 
203 { return __pair.second; } 
204 
205 template<typename _Tp1, typename _Tp2> 
206 static constexpr _Tp2&& 
207 __move_get(pair<_Tp1, _Tp2>&& __pair) noexcept 
208 { return std::forward<_Tp2>(__pair.second); } 
209 
210 template<typename _Tp1, typename _Tp2> 
211 static constexpr const _Tp2& 
212 __const_get(const pair<_Tp1, _Tp2>& __pair) noexcept 
213 { return __pair.second; } 
214 
215 template<typename _Tp1, typename _Tp2> 
216 static constexpr const _Tp2&& 
217 __const_move_get(const pair<_Tp1, _Tp2>&& __pair) noexcept 
218 { return std::forward<const _Tp2>(__pair.second); } 
219 }; 
220 
221 template<size_t _Int, class _Tp1, class _Tp2> 
222 constexpr typename tuple_element<_Int, pair<_Tp1, _Tp2>>::type& 
223 get(pair<_Tp1, _Tp2>& __in) noexcept 
224 { return __pair_get<_Int>::__get(__in); } 
225 
226 template<size_t _Int, class _Tp1, class _Tp2> 
227 constexpr typename tuple_element<_Int, pair<_Tp1, _Tp2>>::type&& 
228 get(pair<_Tp1, _Tp2>&& __in) noexcept 
229 { return __pair_get<_Int>::__move_get(std::move(__in)); } 
230 
231 template<size_t _Int, class _Tp1, class _Tp2> 
232 constexpr const typename tuple_element<_Int, pair<_Tp1, _Tp2>>::type& 
233 get(const pair<_Tp1, _Tp2>& __in) noexcept 
234 { return __pair_get<_Int>::__const_get(__in); } 
235 
236 template<size_t _Int, class _Tp1, class _Tp2> 
237 constexpr const typename tuple_element<_Int, pair<_Tp1, _Tp2>>::type&& 
238 get(const pair<_Tp1, _Tp2>&& __in) noexcept 
239 { return __pair_get<_Int>::__const_move_get(std::move(__in)); } 
240 
241#if __cplusplus >= 201402L 
242 
243#define __cpp_lib_tuples_by_type 201304 
244 
245 template <typename _Tp, typename _Up> 
246 constexpr _Tp& 
247 get(pair<_Tp, _Up>& __p) noexcept 
248 { return __p.first; } 
249 
250 template <typename _Tp, typename _Up> 
251 constexpr const _Tp& 
252 get(const pair<_Tp, _Up>& __p) noexcept 
253 { return __p.first; } 
254 
255 template <typename _Tp, typename _Up> 
256 constexpr _Tp&& 
257 get(pair<_Tp, _Up>&& __p) noexcept 
258 { return std::move(__p.first); } 
259 
260 template <typename _Tp, typename _Up> 
261 constexpr const _Tp&& 
262 get(const pair<_Tp, _Up>&& __p) noexcept 
263 { return std::move(__p.first); } 
264 
265 template <typename _Tp, typename _Up> 
266 constexpr _Tp& 
267 get(pair<_Up, _Tp>& __p) noexcept 
268 { return __p.second; } 
269 
270 template <typename _Tp, typename _Up> 
271 constexpr const _Tp& 
272 get(const pair<_Up, _Tp>& __p) noexcept 
273 { return __p.second; } 
274 
275 template <typename _Tp, typename _Up> 
276 constexpr _Tp&& 
277 get(pair<_Up, _Tp>&& __p) noexcept 
278 { return std::move(__p.second); } 
279 
280 template <typename _Tp, typename _Up> 
281 constexpr const _Tp&& 
282 get(const pair<_Up, _Tp>&& __p) noexcept 
283 { return std::move(__p.second); } 
284 
285#define __cpp_lib_exchange_function 201304 
286 
287 /// Assign @p __new_val to @p __obj and return its previous value. 
288 template <typename _Tp, typename _Up = _Tp> 
289 _GLIBCXX20_CONSTEXPR 
290 inline _Tp 
291 exchange(_Tp& __obj, _Up&& __new_val) 
292 { return std::__exchange(__obj, std::forward<_Up>(__new_val)); } 
293 
294#endif // C++14 
295 
296 // Stores a tuple of indices. Used by tuple and pair, and by bind() to 
297 // extract the elements in a tuple. 
298 template<size_t... _Indexes> struct _Index_tuple { }; 
299 
300 // Builds an _Index_tuple<0, 1, 2, ..., _Num-1>. 
301 template<size_t _Num> 
302 struct _Build_index_tuple 
303 { 
304#if __has_builtin(__make_integer_seq) 
305 template<typename, size_t... _Indices> 
306 using _IdxTuple = _Index_tuple<_Indices...>; 
307 
308 // Clang defines __make_integer_seq for this purpose. 
309 using __type = __make_integer_seq<_IdxTuple, size_t, _Num>; 
310#else 
311 // For GCC and other compilers, use __integer_pack instead. 
312 using __type = _Index_tuple<__integer_pack(_Num)...>; 
313#endif 
314 }; 
315 
316#if __cplusplus >= 201402L 
317 
318#define __cpp_lib_integer_sequence 201304 
319 
320 /// Class template integer_sequence 
321 template<typename _Tp, _Tp... _Idx> 
322 struct integer_sequence 
323 { 
324 typedef _Tp value_type; 
325 static constexpr size_t size() noexcept { return sizeof...(_Idx); } 
326 }; 
327 
328 /// Alias template make_integer_sequence 
329 template<typename _Tp, _Tp _Num> 
330 using make_integer_sequence 
331#if __has_builtin(__make_integer_seq) 
332 = __make_integer_seq<integer_sequence, _Tp, _Num>; 
333#else 
334 = integer_sequence<_Tp, __integer_pack(_Num)...>; 
335#endif 
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 inline constexpr bool __is_in_place_type_v = false; 
376 
377 template<typename _Tp> 
378 inline constexpr bool __is_in_place_type_v<in_place_type_t<_Tp>> = true; 
379 
380 template<typename _Tp> 
381 using __is_in_place_type = bool_constant<__is_in_place_type_v<_Tp>>; 
382 
383#define __cpp_lib_as_const 201510 
384 template<typename _Tp> 
385 [[nodiscard]] 
386 constexpr add_const_t<_Tp>& 
387 as_const(_Tp& __t) noexcept 
388 { return __t; } 
389 
390 template<typename _Tp> 
391 void as_const(const _Tp&&) = delete; 
392 
393#if __cplusplus > 201703L 
394#define __cpp_lib_integer_comparison_functions 202002L 
395 
396 template<typename _Tp, typename _Up> 
397 constexpr bool 
398 cmp_equal(_Tp __t, _Up __u) noexcept 
399 { 
400 static_assert(__is_standard_integer<_Tp>::value); 
401 static_assert(__is_standard_integer<_Up>::value); 
402 
403 if constexpr (is_signed_v<_Tp> == is_signed_v<_Up>) 
404 return __t == __u; 
405 else if constexpr (is_signed_v<_Tp>) 
406 return __t >= 0 && make_unsigned_t<_Tp>(__t) == __u; 
407 else 
408 return __u >= 0 && __t == make_unsigned_t<_Up>(__u); 
409 } 
410 
411 template<typename _Tp, typename _Up> 
412 constexpr bool 
413 cmp_not_equal(_Tp __t, _Up __u) noexcept 
414 { return !std::cmp_equal(__t, __u); } 
415 
416 template<typename _Tp, typename _Up> 
417 constexpr bool 
418 cmp_less(_Tp __t, _Up __u) noexcept 
419 { 
420 static_assert(__is_standard_integer<_Tp>::value); 
421 static_assert(__is_standard_integer<_Up>::value); 
422 
423 if constexpr (is_signed_v<_Tp> == is_signed_v<_Up>) 
424 return __t < __u; 
425 else if constexpr (is_signed_v<_Tp>) 
426 return __t < 0 || make_unsigned_t<_Tp>(__t) < __u; 
427 else 
428 return __u >= 0 && __t < make_unsigned_t<_Up>(__u); 
429 } 
430 
431 template<typename _Tp, typename _Up> 
432 constexpr bool 
433 cmp_greater(_Tp __t, _Up __u) noexcept 
434 { return std::cmp_less(__u, __t); } 
435 
436 template<typename _Tp, typename _Up> 
437 constexpr bool 
438 cmp_less_equal(_Tp __t, _Up __u) noexcept 
439 { return !std::cmp_less(__u, __t); } 
440 
441 template<typename _Tp, typename _Up> 
442 constexpr bool 
443 cmp_greater_equal(_Tp __t, _Up __u) noexcept 
444 { return !std::cmp_less(__t, __u); } 
445 
446 template<typename _Up, typename _Tp> 
447 constexpr bool 
448 in_range(_Tp __t) noexcept 
449 { 
450 static_assert(__is_standard_integer<_Up>::value); 
451 static_assert(__is_standard_integer<_Tp>::value); 
452 using __gnu_cxx::__int_traits; 
453 
454 if constexpr (is_signed_v<_Tp> == is_signed_v<_Up>) 
455 return __int_traits<_Up>::__min <= __t 
456 && __t <= __int_traits<_Up>::__max; 
457 else if constexpr (is_signed_v<_Tp>) 
458 return __t >= 0 
459 && make_unsigned_t<_Tp>(__t) <= __int_traits<_Up>::__max; 
460 else 
461 return __t <= make_unsigned_t<_Up>(__int_traits<_Up>::__max); 
462 } 
463 
464#if __cplusplus > 202002L 
465#define __cpp_lib_to_underlying 202102L 
466 /// Convert an object of enumeration type to its underlying type. 
467 template<typename _Tp> 
468 [[nodiscard]] 
469 constexpr underlying_type_t<_Tp> 
470 to_underlying(_Tp __value) noexcept 
471 { return static_cast<underlying_type_t<_Tp>>(__value); } 
472#endif // C++23 
473#endif // C++20 
474#endif // C++17 
475 
476_GLIBCXX_END_NAMESPACE_VERSION 
477} // namespace 
478 
479#endif 
480 
481#endif /* _GLIBCXX_UTILITY */ 
482