libstdc++
tuple
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1// <tuple> -*- C++ -*-
2
3// Copyright (C) 2007-2021 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/** @file include/tuple
26 * This is a Standard C++ Library header.
27 */
28
29#ifndef _GLIBCXX_TUPLE
30#define _GLIBCXX_TUPLE 1
31
32#pragma GCC system_header
33
34#if __cplusplus < 201103L
35# include <bits/c++0x_warning.h>
36#else
37
38#include <utility>
39#include <array>
40#include <bits/uses_allocator.h>
41#include <bits/invoke.h>
42#if __cplusplus > 201703L
43# include <compare>
44# define __cpp_lib_constexpr_tuple 201811L
45#endif
46
47namespace std _GLIBCXX_VISIBILITY(default)
48{
49_GLIBCXX_BEGIN_NAMESPACE_VERSION
50
51 /**
52 * @addtogroup utilities
53 * @{
54 */
55
56 template<typename... _Elements>
57 class tuple;
58
59 template<typename _Tp>
60 struct __is_empty_non_tuple : is_empty<_Tp> { };
61
62 // Using EBO for elements that are tuples causes ambiguous base errors.
63 template<typename _El0, typename... _El>
64 struct __is_empty_non_tuple<tuple<_El0, _El...>> : false_type { };
65
66 // Use the Empty Base-class Optimization for empty, non-final types.
67 template<typename _Tp>
68 using __empty_not_final
69 = typename conditional<__is_final(_Tp), false_type,
70 __is_empty_non_tuple<_Tp>>::type;
71
72 template<size_t _Idx, typename _Head,
73 bool = __empty_not_final<_Head>::value>
74 struct _Head_base;
75
76#if __has_cpp_attribute(__no_unique_address__)
77 template<size_t _Idx, typename _Head>
78 struct _Head_base<_Idx, _Head, true>
79 {
80 constexpr _Head_base()
81 : _M_head_impl() { }
82
83 constexpr _Head_base(const _Head& __h)
84 : _M_head_impl(__h) { }
85
86 constexpr _Head_base(const _Head_base&) = default;
87 constexpr _Head_base(_Head_base&&) = default;
88
89 template<typename _UHead>
90 constexpr _Head_base(_UHead&& __h)
91 : _M_head_impl(std::forward<_UHead>(__h)) { }
92
93 _GLIBCXX20_CONSTEXPR
94 _Head_base(allocator_arg_t, __uses_alloc0)
95 : _M_head_impl() { }
96
97 template<typename _Alloc>
98 _GLIBCXX20_CONSTEXPR
99 _Head_base(allocator_arg_t, __uses_alloc1<_Alloc> __a)
100 : _M_head_impl(allocator_arg, *__a._M_a) { }
101
102 template<typename _Alloc>
103 _GLIBCXX20_CONSTEXPR
104 _Head_base(allocator_arg_t, __uses_alloc2<_Alloc> __a)
105 : _M_head_impl(*__a._M_a) { }
106
107 template<typename _UHead>
108 _GLIBCXX20_CONSTEXPR
109 _Head_base(__uses_alloc0, _UHead&& __uhead)
110 : _M_head_impl(std::forward<_UHead>(__uhead)) { }
111
112 template<typename _Alloc, typename _UHead>
113 _GLIBCXX20_CONSTEXPR
114 _Head_base(__uses_alloc1<_Alloc> __a, _UHead&& __uhead)
115 : _M_head_impl(allocator_arg, *__a._M_a, std::forward<_UHead>(__uhead))
116 { }
117
118 template<typename _Alloc, typename _UHead>
119 _GLIBCXX20_CONSTEXPR
120 _Head_base(__uses_alloc2<_Alloc> __a, _UHead&& __uhead)
121 : _M_head_impl(std::forward<_UHead>(__uhead), *__a._M_a) { }
122
123 static constexpr _Head&
124 _M_head(_Head_base& __b) noexcept { return __b._M_head_impl; }
125
126 static constexpr const _Head&
127 _M_head(const _Head_base& __b) noexcept { return __b._M_head_impl; }
128
129 [[__no_unique_address__]] _Head _M_head_impl;
130 };
131#else
132 template<size_t _Idx, typename _Head>
133 struct _Head_base<_Idx, _Head, true>
134 : public _Head
135 {
136 constexpr _Head_base()
137 : _Head() { }
138
139 constexpr _Head_base(const _Head& __h)
140 : _Head(__h) { }
141
142 constexpr _Head_base(const _Head_base&) = default;
143 constexpr _Head_base(_Head_base&&) = default;
144
145 template<typename _UHead>
146 constexpr _Head_base(_UHead&& __h)
147 : _Head(std::forward<_UHead>(__h)) { }
148
149 _GLIBCXX20_CONSTEXPR
150 _Head_base(allocator_arg_t, __uses_alloc0)
151 : _Head() { }
152
153 template<typename _Alloc>
154 _GLIBCXX20_CONSTEXPR
155 _Head_base(allocator_arg_t, __uses_alloc1<_Alloc> __a)
156 : _Head(allocator_arg, *__a._M_a) { }
157
158 template<typename _Alloc>
159 _GLIBCXX20_CONSTEXPR
160 _Head_base(allocator_arg_t, __uses_alloc2<_Alloc> __a)
161 : _Head(*__a._M_a) { }
162
163 template<typename _UHead>
164 _GLIBCXX20_CONSTEXPR
165 _Head_base(__uses_alloc0, _UHead&& __uhead)
166 : _Head(std::forward<_UHead>(__uhead)) { }
167
168 template<typename _Alloc, typename _UHead>
169 _GLIBCXX20_CONSTEXPR
170 _Head_base(__uses_alloc1<_Alloc> __a, _UHead&& __uhead)
171 : _Head(allocator_arg, *__a._M_a, std::forward<_UHead>(__uhead)) { }
172
173 template<typename _Alloc, typename _UHead>
174 _GLIBCXX20_CONSTEXPR
175 _Head_base(__uses_alloc2<_Alloc> __a, _UHead&& __uhead)
176 : _Head(std::forward<_UHead>(__uhead), *__a._M_a) { }
177
178 static constexpr _Head&
179 _M_head(_Head_base& __b) noexcept { return __b; }
180
181 static constexpr const _Head&
182 _M_head(const _Head_base& __b) noexcept { return __b; }
183 };
184#endif
185
186 template<size_t _Idx, typename _Head>
187 struct _Head_base<_Idx, _Head, false>
188 {
189 constexpr _Head_base()
190 : _M_head_impl() { }
191
192 constexpr _Head_base(const _Head& __h)
193 : _M_head_impl(__h) { }
194
195 constexpr _Head_base(const _Head_base&) = default;
196 constexpr _Head_base(_Head_base&&) = default;
197
198 template<typename _UHead>
199 constexpr _Head_base(_UHead&& __h)
200 : _M_head_impl(std::forward<_UHead>(__h)) { }
201
202 _GLIBCXX20_CONSTEXPR
203 _Head_base(allocator_arg_t, __uses_alloc0)
204 : _M_head_impl() { }
205
206 template<typename _Alloc>
207 _GLIBCXX20_CONSTEXPR
208 _Head_base(allocator_arg_t, __uses_alloc1<_Alloc> __a)
209 : _M_head_impl(allocator_arg, *__a._M_a) { }
210
211 template<typename _Alloc>
212 _GLIBCXX20_CONSTEXPR
213 _Head_base(allocator_arg_t, __uses_alloc2<_Alloc> __a)
214 : _M_head_impl(*__a._M_a) { }
215
216 template<typename _UHead>
217 _GLIBCXX20_CONSTEXPR
218 _Head_base(__uses_alloc0, _UHead&& __uhead)
219 : _M_head_impl(std::forward<_UHead>(__uhead)) { }
220
221 template<typename _Alloc, typename _UHead>
222 _GLIBCXX20_CONSTEXPR
223 _Head_base(__uses_alloc1<_Alloc> __a, _UHead&& __uhead)
224 : _M_head_impl(allocator_arg, *__a._M_a, std::forward<_UHead>(__uhead))
225 { }
226
227 template<typename _Alloc, typename _UHead>
228 _GLIBCXX20_CONSTEXPR
229 _Head_base(__uses_alloc2<_Alloc> __a, _UHead&& __uhead)
230 : _M_head_impl(std::forward<_UHead>(__uhead), *__a._M_a) { }
231
232 static constexpr _Head&
233 _M_head(_Head_base& __b) noexcept { return __b._M_head_impl; }
234
235 static constexpr const _Head&
236 _M_head(const _Head_base& __b) noexcept { return __b._M_head_impl; }
237
238 _Head _M_head_impl;
239 };
240
241 /**
242 * Contains the actual implementation of the @c tuple template, stored
243 * as a recursive inheritance hierarchy from the first element (most
244 * derived class) to the last (least derived class). The @c Idx
245 * parameter gives the 0-based index of the element stored at this
246 * point in the hierarchy; we use it to implement a constant-time
247 * get() operation.
248 */
249 template<size_t _Idx, typename... _Elements>
250 struct _Tuple_impl;
251
252 /**
253 * Recursive tuple implementation. Here we store the @c Head element
254 * and derive from a @c Tuple_impl containing the remaining elements
255 * (which contains the @c Tail).
256 */
257 template<size_t _Idx, typename _Head, typename... _Tail>
258 struct _Tuple_impl<_Idx, _Head, _Tail...>
259 : public _Tuple_impl<_Idx + 1, _Tail...>,
260 private _Head_base<_Idx, _Head>
261 {
262 template<size_t, typename...> friend struct _Tuple_impl;
263
264 typedef _Tuple_impl<_Idx + 1, _Tail...> _Inherited;
265 typedef _Head_base<_Idx, _Head> _Base;
266
267 static constexpr _Head&
268 _M_head(_Tuple_impl& __t) noexcept { return _Base::_M_head(__t); }
269
270 static constexpr const _Head&
271 _M_head(const _Tuple_impl& __t) noexcept { return _Base::_M_head(__t); }
272
273 static constexpr _Inherited&
274 _M_tail(_Tuple_impl& __t) noexcept { return __t; }
275
276 static constexpr const _Inherited&
277 _M_tail(const _Tuple_impl& __t) noexcept { return __t; }
278
279 constexpr _Tuple_impl()
280 : _Inherited(), _Base() { }
281
282 explicit constexpr
283 _Tuple_impl(const _Head& __head, const _Tail&... __tail)
284 : _Inherited(__tail...), _Base(__head)
285 { }
286
287 template<typename _UHead, typename... _UTail,
288 typename = __enable_if_t<sizeof...(_Tail) == sizeof...(_UTail)>>
289 explicit constexpr
290 _Tuple_impl(_UHead&& __head, _UTail&&... __tail)
291 : _Inherited(std::forward<_UTail>(__tail)...),
292 _Base(std::forward<_UHead>(__head))
293 { }
294
295 constexpr _Tuple_impl(const _Tuple_impl&) = default;
296
297 // _GLIBCXX_RESOLVE_LIB_DEFECTS
298 // 2729. Missing SFINAE on std::pair::operator=
299 _Tuple_impl& operator=(const _Tuple_impl&) = delete;
300
301 _Tuple_impl(_Tuple_impl&&) = default;
302
303 template<typename... _UElements>
304 constexpr
305 _Tuple_impl(const _Tuple_impl<_Idx, _UElements...>& __in)
306 : _Inherited(_Tuple_impl<_Idx, _UElements...>::_M_tail(__in)),
307 _Base(_Tuple_impl<_Idx, _UElements...>::_M_head(__in))
308 { }
309
310 template<typename _UHead, typename... _UTails>
311 constexpr
312 _Tuple_impl(_Tuple_impl<_Idx, _UHead, _UTails...>&& __in)
313 : _Inherited(std::move
314 (_Tuple_impl<_Idx, _UHead, _UTails...>::_M_tail(__in))),
315 _Base(std::forward<_UHead>
316 (_Tuple_impl<_Idx, _UHead, _UTails...>::_M_head(__in)))
317 { }
318
319 template<typename _Alloc>
320 _GLIBCXX20_CONSTEXPR
321 _Tuple_impl(allocator_arg_t __tag, const _Alloc& __a)
322 : _Inherited(__tag, __a),
323 _Base(__tag, __use_alloc<_Head>(__a))
324 { }
325
326 template<typename _Alloc>
327 _GLIBCXX20_CONSTEXPR
328 _Tuple_impl(allocator_arg_t __tag, const _Alloc& __a,
329 const _Head& __head, const _Tail&... __tail)
330 : _Inherited(__tag, __a, __tail...),
331 _Base(__use_alloc<_Head, _Alloc, _Head>(__a), __head)
332 { }
333
334 template<typename _Alloc, typename _UHead, typename... _UTail,
335 typename = __enable_if_t<sizeof...(_Tail) == sizeof...(_UTail)>>
336 _GLIBCXX20_CONSTEXPR
337 _Tuple_impl(allocator_arg_t __tag, const _Alloc& __a,
338 _UHead&& __head, _UTail&&... __tail)
339 : _Inherited(__tag, __a, std::forward<_UTail>(__tail)...),
340 _Base(__use_alloc<_Head, _Alloc, _UHead>(__a),
341 std::forward<_UHead>(__head))
342 { }
343
344 template<typename _Alloc>
345 _GLIBCXX20_CONSTEXPR
346 _Tuple_impl(allocator_arg_t __tag, const _Alloc& __a,
347 const _Tuple_impl& __in)
348 : _Inherited(__tag, __a, _M_tail(__in)),
349 _Base(__use_alloc<_Head, _Alloc, _Head>(__a), _M_head(__in))
350 { }
351
352 template<typename _Alloc>
353 _GLIBCXX20_CONSTEXPR
354 _Tuple_impl(allocator_arg_t __tag, const _Alloc& __a,
355 _Tuple_impl&& __in)
356 : _Inherited(__tag, __a, std::move(_M_tail(__in))),
357 _Base(__use_alloc<_Head, _Alloc, _Head>(__a),
358 std::forward<_Head>(_M_head(__in)))
359 { }
360
361 template<typename _Alloc, typename _UHead, typename... _UTails>
362 _GLIBCXX20_CONSTEXPR
363 _Tuple_impl(allocator_arg_t __tag, const _Alloc& __a,
364 const _Tuple_impl<_Idx, _UHead, _UTails...>& __in)
365 : _Inherited(__tag, __a,
366 _Tuple_impl<_Idx, _UHead, _UTails...>::_M_tail(__in)),
367 _Base(__use_alloc<_Head, _Alloc, const _UHead&>(__a),
368 _Tuple_impl<_Idx, _UHead, _UTails...>::_M_head(__in))
369 { }
370
371 template<typename _Alloc, typename _UHead, typename... _UTails>
372 _GLIBCXX20_CONSTEXPR
373 _Tuple_impl(allocator_arg_t __tag, const _Alloc& __a,
374 _Tuple_impl<_Idx, _UHead, _UTails...>&& __in)
375 : _Inherited(__tag, __a, std::move
376 (_Tuple_impl<_Idx, _UHead, _UTails...>::_M_tail(__in))),
377 _Base(__use_alloc<_Head, _Alloc, _UHead>(__a),
378 std::forward<_UHead>
379 (_Tuple_impl<_Idx, _UHead, _UTails...>::_M_head(__in)))
380 { }
381
382 template<typename... _UElements>
383 _GLIBCXX20_CONSTEXPR
384 void
385 _M_assign(const _Tuple_impl<_Idx, _UElements...>& __in)
386 {
387 _M_head(*this) = _Tuple_impl<_Idx, _UElements...>::_M_head(__in);
388 _M_tail(*this)._M_assign(
389 _Tuple_impl<_Idx, _UElements...>::_M_tail(__in));
390 }
391
392 template<typename _UHead, typename... _UTails>
393 _GLIBCXX20_CONSTEXPR
394 void
395 _M_assign(_Tuple_impl<_Idx, _UHead, _UTails...>&& __in)
396 {
397 _M_head(*this) = std::forward<_UHead>
398 (_Tuple_impl<_Idx, _UHead, _UTails...>::_M_head(__in));
399 _M_tail(*this)._M_assign(
400 std::move(_Tuple_impl<_Idx, _UHead, _UTails...>::_M_tail(__in)));
401 }
402
403 protected:
404 _GLIBCXX20_CONSTEXPR
405 void
406 _M_swap(_Tuple_impl& __in)
407 {
408 using std::swap;
409 swap(_M_head(*this), _M_head(__in));
410 _Inherited::_M_swap(_M_tail(__in));
411 }
412 };
413
414 // Basis case of inheritance recursion.
415 template<size_t _Idx, typename _Head>
416 struct _Tuple_impl<_Idx, _Head>
417 : private _Head_base<_Idx, _Head>
418 {
419 template<size_t, typename...> friend struct _Tuple_impl;
420
421 typedef _Head_base<_Idx, _Head> _Base;
422
423 static constexpr _Head&
424 _M_head(_Tuple_impl& __t) noexcept { return _Base::_M_head(__t); }
425
426 static constexpr const _Head&
427 _M_head(const _Tuple_impl& __t) noexcept { return _Base::_M_head(__t); }
428
429 constexpr
430 _Tuple_impl()
431 : _Base() { }
432
433 explicit constexpr
434 _Tuple_impl(const _Head& __head)
435 : _Base(__head)
436 { }
437
438 template<typename _UHead>
439 explicit constexpr
440 _Tuple_impl(_UHead&& __head)
441 : _Base(std::forward<_UHead>(__head))
442 { }
443
444 constexpr _Tuple_impl(const _Tuple_impl&) = default;
445
446 // _GLIBCXX_RESOLVE_LIB_DEFECTS
447 // 2729. Missing SFINAE on std::pair::operator=
448 _Tuple_impl& operator=(const _Tuple_impl&) = delete;
449
450#if _GLIBCXX_INLINE_VERSION
451 _Tuple_impl(_Tuple_impl&&) = default;
452#else
453 constexpr
454 _Tuple_impl(_Tuple_impl&& __in)
455 noexcept(is_nothrow_move_constructible<_Head>::value)
456 : _Base(static_cast<_Base&&>(__in))
457 { }
458#endif
459
460 template<typename _UHead>
461 constexpr
462 _Tuple_impl(const _Tuple_impl<_Idx, _UHead>& __in)
463 : _Base(_Tuple_impl<_Idx, _UHead>::_M_head(__in))
464 { }
465
466 template<typename _UHead>
467 constexpr
468 _Tuple_impl(_Tuple_impl<_Idx, _UHead>&& __in)
469 : _Base(std::forward<_UHead>(_Tuple_impl<_Idx, _UHead>::_M_head(__in)))
470 { }
471
472 template<typename _Alloc>
473 _GLIBCXX20_CONSTEXPR
474 _Tuple_impl(allocator_arg_t __tag, const _Alloc& __a)
475 : _Base(__tag, __use_alloc<_Head>(__a))
476 { }
477
478 template<typename _Alloc>
479 _GLIBCXX20_CONSTEXPR
480 _Tuple_impl(allocator_arg_t __tag, const _Alloc& __a,
481 const _Head& __head)
482 : _Base(__use_alloc<_Head, _Alloc, const _Head&>(__a), __head)
483 { }
484
485 template<typename _Alloc, typename _UHead>
486 _GLIBCXX20_CONSTEXPR
487 _Tuple_impl(allocator_arg_t __tag, const _Alloc& __a,
488 _UHead&& __head)
489 : _Base(__use_alloc<_Head, _Alloc, _UHead>(__a),
490 std::forward<_UHead>(__head))
491 { }
492
493 template<typename _Alloc>
494 _GLIBCXX20_CONSTEXPR
495 _Tuple_impl(allocator_arg_t __tag, const _Alloc& __a,
496 const _Tuple_impl& __in)
497 : _Base(__use_alloc<_Head, _Alloc, const _Head&>(__a), _M_head(__in))
498 { }
499
500 template<typename _Alloc>
501 _GLIBCXX20_CONSTEXPR
502 _Tuple_impl(allocator_arg_t __tag, const _Alloc& __a,
503 _Tuple_impl&& __in)
504 : _Base(__use_alloc<_Head, _Alloc, _Head>(__a),
505 std::forward<_Head>(_M_head(__in)))
506 { }
507
508 template<typename _Alloc, typename _UHead>
509 _GLIBCXX20_CONSTEXPR
510 _Tuple_impl(allocator_arg_t __tag, const _Alloc& __a,
511 const _Tuple_impl<_Idx, _UHead>& __in)
512 : _Base(__use_alloc<_Head, _Alloc, const _UHead&>(__a),
513 _Tuple_impl<_Idx, _UHead>::_M_head(__in))
514 { }
515
516 template<typename _Alloc, typename _UHead>
517 _GLIBCXX20_CONSTEXPR
518 _Tuple_impl(allocator_arg_t __tag, const _Alloc& __a,
519 _Tuple_impl<_Idx, _UHead>&& __in)
520 : _Base(__use_alloc<_Head, _Alloc, _UHead>(__a),
521 std::forward<_UHead>(_Tuple_impl<_Idx, _UHead>::_M_head(__in)))
522 { }
523
524 template<typename _UHead>
525 _GLIBCXX20_CONSTEXPR
526 void
527 _M_assign(const _Tuple_impl<_Idx, _UHead>& __in)
528 {
529 _M_head(*this) = _Tuple_impl<_Idx, _UHead>::_M_head(__in);
530 }
531
532 template<typename _UHead>
533 _GLIBCXX20_CONSTEXPR
534 void
535 _M_assign(_Tuple_impl<_Idx, _UHead>&& __in)
536 {
537 _M_head(*this)
538 = std::forward<_UHead>(_Tuple_impl<_Idx, _UHead>::_M_head(__in));
539 }
540
541 protected:
542 _GLIBCXX20_CONSTEXPR
543 void
544 _M_swap(_Tuple_impl& __in)
545 {
546 using std::swap;
547 swap(_M_head(*this), _M_head(__in));
548 }
549 };
550
551 // Concept utility functions, reused in conditionally-explicit
552 // constructors.
553 template<bool, typename... _Types>
554 struct _TupleConstraints
555 {
556 // Constraint for a non-explicit constructor.
557 // True iff each Ti in _Types... can be constructed from Ui in _UTypes...
558 // and every Ui is implicitly convertible to Ti.
559 template<typename... _UTypes>
560 static constexpr bool __is_implicitly_constructible()
561 {
562 return __and_<is_constructible<_Types, _UTypes>...,
563 is_convertible<_UTypes, _Types>...
564 >::value;
565 }
566
567 // Constraint for a non-explicit constructor.
568 // True iff each Ti in _Types... can be constructed from Ui in _UTypes...
569 // but not every Ui is implicitly convertible to Ti.
570 template<typename... _UTypes>
571 static constexpr bool __is_explicitly_constructible()
572 {
573 return __and_<is_constructible<_Types, _UTypes>...,
574 __not_<__and_<is_convertible<_UTypes, _Types>...>>
575 >::value;
576 }
577
578 static constexpr bool __is_implicitly_default_constructible()
579 {
580 return __and_<std::__is_implicitly_default_constructible<_Types>...
581 >::value;
582 }
583
584 static constexpr bool __is_explicitly_default_constructible()
585 {
586 return __and_<is_default_constructible<_Types>...,
587 __not_<__and_<
588 std::__is_implicitly_default_constructible<_Types>...>
589 >>::value;
590 }
591 };
592
593 // Partial specialization used when a required precondition isn't met,
594 // e.g. when sizeof...(_Types) != sizeof...(_UTypes).
595 template<typename... _Types>
596 struct _TupleConstraints<false, _Types...>
597 {
598 template<typename... _UTypes>
599 static constexpr bool __is_implicitly_constructible()
600 { return false; }
601
602 template<typename... _UTypes>
603 static constexpr bool __is_explicitly_constructible()
604 { return false; }
605 };
606
607 /// Primary class template, tuple
608 template<typename... _Elements>
609 class tuple : public _Tuple_impl<0, _Elements...>
610 {
611 typedef _Tuple_impl<0, _Elements...> _Inherited;
612
613 template<bool _Cond>
614 using _TCC = _TupleConstraints<_Cond, _Elements...>;
615
616 // Constraint for non-explicit default constructor
617 template<bool _Dummy>
618 using _ImplicitDefaultCtor = __enable_if_t<
619 _TCC<_Dummy>::__is_implicitly_default_constructible(),
620 bool>;
621
622 // Constraint for explicit default constructor
623 template<bool _Dummy>
624 using _ExplicitDefaultCtor = __enable_if_t<
625 _TCC<_Dummy>::__is_explicitly_default_constructible(),
626 bool>;
627
628 // Constraint for non-explicit constructors
629 template<bool _Cond, typename... _Args>
630 using _ImplicitCtor = __enable_if_t<
631 _TCC<_Cond>::template __is_implicitly_constructible<_Args...>(),
632 bool>;
633
634 // Constraint for non-explicit constructors
635 template<bool _Cond, typename... _Args>
636 using _ExplicitCtor = __enable_if_t<
637 _TCC<_Cond>::template __is_explicitly_constructible<_Args...>(),
638 bool>;
639
640 template<typename... _UElements>
641 static constexpr
642 __enable_if_t<sizeof...(_UElements) == sizeof...(_Elements), bool>
643 __assignable()
644 { return __and_<is_assignable<_Elements&, _UElements>...>::value; }
645
646 // Condition for noexcept-specifier of an assignment operator.
647 template<typename... _UElements>
648 static constexpr bool __nothrow_assignable()
649 {
650 return
651 __and_<is_nothrow_assignable<_Elements&, _UElements>...>::value;
652 }
653
654 // Condition for noexcept-specifier of a constructor.
655 template<typename... _UElements>
656 static constexpr bool __nothrow_constructible()
657 {
658 return
659 __and_<is_nothrow_constructible<_Elements, _UElements>...>::value;
660 }
661
662 // Constraint for tuple(_UTypes&&...) where sizeof...(_UTypes) == 1.
663 template<typename _Up>
664 static constexpr bool __valid_args()
665 {
666 return sizeof...(_Elements) == 1
667 && !is_same<tuple, __remove_cvref_t<_Up>>::value;
668 }
669
670 // Constraint for tuple(_UTypes&&...) where sizeof...(_UTypes) > 1.
671 template<typename, typename, typename... _Tail>
672 static constexpr bool __valid_args()
673 { return (sizeof...(_Tail) + 2) == sizeof...(_Elements); }
674
675 /* Constraint for constructors with a tuple<UTypes...> parameter ensures
676 * that the constructor is only viable when it would not interfere with
677 * tuple(UTypes&&...) or tuple(const tuple&) or tuple(tuple&&).
678 * Such constructors are only viable if:
679 * either sizeof...(Types) != 1,
680 * or (when Types... expands to T and UTypes... expands to U)
681 * is_convertible_v<TUPLE, T>, is_constructible_v<T, TUPLE>,
682 * and is_same_v<T, U> are all false.
683 */
684 template<typename _Tuple, typename = tuple,
685 typename = __remove_cvref_t<_Tuple>>
686 struct _UseOtherCtor
687 : false_type
688 { };
689 // If TUPLE is convertible to the single element in *this,
690 // then TUPLE should match tuple(UTypes&&...) instead.
691 template<typename _Tuple, typename _Tp, typename _Up>
692 struct _UseOtherCtor<_Tuple, tuple<_Tp>, tuple<_Up>>
693 : __or_<is_convertible<_Tuple, _Tp>, is_constructible<_Tp, _Tuple>>
694 { };
695 // If TUPLE and *this each have a single element of the same type,
696 // then TUPLE should match a copy/move constructor instead.
697 template<typename _Tuple, typename _Tp>
698 struct _UseOtherCtor<_Tuple, tuple<_Tp>, tuple<_Tp>>
699 : true_type
700 { };
701
702 // Return true iff sizeof...(Types) == 1 && tuple_size_v<TUPLE> == 1
703 // and the single element in Types can be initialized from TUPLE,
704 // or is the same type as tuple_element_t<0, TUPLE>.
705 template<typename _Tuple>
706 static constexpr bool __use_other_ctor()
707 { return _UseOtherCtor<_Tuple>::value; }
708
709 public:
710 template<typename _Dummy = void,
711 _ImplicitDefaultCtor<is_void<_Dummy>::value> = true>
712 constexpr
713 tuple()
714 noexcept(__and_<is_nothrow_default_constructible<_Elements>...>::value)
715 : _Inherited() { }
716
717 template<typename _Dummy = void,
718 _ExplicitDefaultCtor<is_void<_Dummy>::value> = false>
719 explicit constexpr
720 tuple()
721 noexcept(__and_<is_nothrow_default_constructible<_Elements>...>::value)
722 : _Inherited() { }
723
724 template<bool _NotEmpty = (sizeof...(_Elements) >= 1),
725 _ImplicitCtor<_NotEmpty, const _Elements&...> = true>
726 constexpr
727 tuple(const _Elements&... __elements)
728 noexcept(__nothrow_constructible<const _Elements&...>())
729 : _Inherited(__elements...) { }
730
731 template<bool _NotEmpty = (sizeof...(_Elements) >= 1),
732 _ExplicitCtor<_NotEmpty, const _Elements&...> = false>
733 explicit constexpr
734 tuple(const _Elements&... __elements)
735 noexcept(__nothrow_constructible<const _Elements&...>())
736 : _Inherited(__elements...) { }
737
738 template<typename... _UElements,
739 bool _Valid = __valid_args<_UElements...>(),
740 _ImplicitCtor<_Valid, _UElements...> = true>
741 constexpr
742 tuple(_UElements&&... __elements)
743 noexcept(__nothrow_constructible<_UElements...>())
744 : _Inherited(std::forward<_UElements>(__elements)...) { }
745
746 template<typename... _UElements,
747 bool _Valid = __valid_args<_UElements...>(),
748 _ExplicitCtor<_Valid, _UElements...> = false>
749 explicit constexpr
750 tuple(_UElements&&... __elements)
751 noexcept(__nothrow_constructible<_UElements...>())
752 : _Inherited(std::forward<_UElements>(__elements)...) { }
753
754 constexpr tuple(const tuple&) = default;
755
756 constexpr tuple(tuple&&) = default;
757
758 template<typename... _UElements,
759 bool _Valid = (sizeof...(_Elements) == sizeof...(_UElements))
760 && !__use_other_ctor<const tuple<_UElements...>&>(),
761 _ImplicitCtor<_Valid, const _UElements&...> = true>
762 constexpr
763 tuple(const tuple<_UElements...>& __in)
764 noexcept(__nothrow_constructible<const _UElements&...>())
765 : _Inherited(static_cast<const _Tuple_impl<0, _UElements...>&>(__in))
766 { }
767
768 template<typename... _UElements,
769 bool _Valid = (sizeof...(_Elements) == sizeof...(_UElements))
770 && !__use_other_ctor<const tuple<_UElements...>&>(),
771 _ExplicitCtor<_Valid, const _UElements&...> = false>
772 explicit constexpr
773 tuple(const tuple<_UElements...>& __in)
774 noexcept(__nothrow_constructible<const _UElements&...>())
775 : _Inherited(static_cast<const _Tuple_impl<0, _UElements...>&>(__in))
776 { }
777
778 template<typename... _UElements,
779 bool _Valid = (sizeof...(_Elements) == sizeof...(_UElements))
780 && !__use_other_ctor<tuple<_UElements...>&&>(),
781 _ImplicitCtor<_Valid, _UElements...> = true>
782 constexpr
783 tuple(tuple<_UElements...>&& __in)
784 noexcept(__nothrow_constructible<_UElements...>())
785 : _Inherited(static_cast<_Tuple_impl<0, _UElements...>&&>(__in)) { }
786
787 template<typename... _UElements,
788 bool _Valid = (sizeof...(_Elements) == sizeof...(_UElements))
789 && !__use_other_ctor<tuple<_UElements...>&&>(),
790 _ExplicitCtor<_Valid, _UElements...> = false>
791 explicit constexpr
792 tuple(tuple<_UElements...>&& __in)
793 noexcept(__nothrow_constructible<_UElements...>())
794 : _Inherited(static_cast<_Tuple_impl<0, _UElements...>&&>(__in)) { }
795
796 // Allocator-extended constructors.
797
798 template<typename _Alloc,
799 _ImplicitDefaultCtor<is_object<_Alloc>::value> = true>
800 _GLIBCXX20_CONSTEXPR
801 tuple(allocator_arg_t __tag, const _Alloc& __a)
802 : _Inherited(__tag, __a) { }
803
804 template<typename _Alloc,
805 _ExplicitDefaultCtor<is_object<_Alloc>::value> = false>
806 _GLIBCXX20_CONSTEXPR
807 explicit
808 tuple(allocator_arg_t __tag, const _Alloc& __a)
809 : _Inherited(__tag, __a) { }
810
811 template<typename _Alloc, bool _NotEmpty = (sizeof...(_Elements) >= 1),
812 _ImplicitCtor<_NotEmpty, const _Elements&...> = true>
813 _GLIBCXX20_CONSTEXPR
814 tuple(allocator_arg_t __tag, const _Alloc& __a,
815 const _Elements&... __elements)
816 : _Inherited(__tag, __a, __elements...) { }
817
818 template<typename _Alloc, bool _NotEmpty = (sizeof...(_Elements) >= 1),
819 _ExplicitCtor<_NotEmpty, const _Elements&...> = false>
820 _GLIBCXX20_CONSTEXPR
821 explicit
822 tuple(allocator_arg_t __tag, const _Alloc& __a,
823 const _Elements&... __elements)
824 : _Inherited(__tag, __a, __elements...) { }
825
826 template<typename _Alloc, typename... _UElements,
827 bool _Valid = __valid_args<_UElements...>(),
828 _ImplicitCtor<_Valid, _UElements...> = true>
829 _GLIBCXX20_CONSTEXPR
830 tuple(allocator_arg_t __tag, const _Alloc& __a,
831 _UElements&&... __elements)
832 : _Inherited(__tag, __a, std::forward<_UElements>(__elements)...)
833 { }
834
835 template<typename _Alloc, typename... _UElements,
836 bool _Valid = __valid_args<_UElements...>(),
837 _ExplicitCtor<_Valid, _UElements...> = false>
838 _GLIBCXX20_CONSTEXPR
839 explicit
840 tuple(allocator_arg_t __tag, const _Alloc& __a,
841 _UElements&&... __elements)
842 : _Inherited(__tag, __a, std::forward<_UElements>(__elements)...)
843 { }
844
845 template<typename _Alloc>
846 _GLIBCXX20_CONSTEXPR
847 tuple(allocator_arg_t __tag, const _Alloc& __a, const tuple& __in)
848 : _Inherited(__tag, __a, static_cast<const _Inherited&>(__in)) { }
849
850 template<typename _Alloc>
851 _GLIBCXX20_CONSTEXPR
852 tuple(allocator_arg_t __tag, const _Alloc& __a, tuple&& __in)
853 : _Inherited(__tag, __a, static_cast<_Inherited&&>(__in)) { }
854
855 template<typename _Alloc, typename... _UElements,
856 bool _Valid = (sizeof...(_Elements) == sizeof...(_UElements))
857 && !__use_other_ctor<const tuple<_UElements...>&>(),
858 _ImplicitCtor<_Valid, const _UElements&...> = true>
859 _GLIBCXX20_CONSTEXPR
860 tuple(allocator_arg_t __tag, const _Alloc& __a,
861 const tuple<_UElements...>& __in)
862 : _Inherited(__tag, __a,
863 static_cast<const _Tuple_impl<0, _UElements...>&>(__in))
864 { }
865
866 template<typename _Alloc, typename... _UElements,
867 bool _Valid = (sizeof...(_Elements) == sizeof...(_UElements))
868 && !__use_other_ctor<const tuple<_UElements...>&>(),
869 _ExplicitCtor<_Valid, const _UElements&...> = false>
870 _GLIBCXX20_CONSTEXPR
871 explicit
872 tuple(allocator_arg_t __tag, const _Alloc& __a,
873 const tuple<_UElements...>& __in)
874 : _Inherited(__tag, __a,
875 static_cast<const _Tuple_impl<0, _UElements...>&>(__in))
876 { }
877
878 template<typename _Alloc, typename... _UElements,
879 bool _Valid = (sizeof...(_Elements) == sizeof...(_UElements))
880 && !__use_other_ctor<tuple<_UElements...>&&>(),
881 _ImplicitCtor<_Valid, _UElements...> = true>
882 _GLIBCXX20_CONSTEXPR
883 tuple(allocator_arg_t __tag, const _Alloc& __a,
884 tuple<_UElements...>&& __in)
885 : _Inherited(__tag, __a,
886 static_cast<_Tuple_impl<0, _UElements...>&&>(__in))
887 { }
888
889 template<typename _Alloc, typename... _UElements,
890 bool _Valid = (sizeof...(_Elements) == sizeof...(_UElements))
891 && !__use_other_ctor<tuple<_UElements...>&&>(),
892 _ExplicitCtor<_Valid, _UElements...> = false>
893 _GLIBCXX20_CONSTEXPR
894 explicit
895 tuple(allocator_arg_t __tag, const _Alloc& __a,
896 tuple<_UElements...>&& __in)
897 : _Inherited(__tag, __a,
898 static_cast<_Tuple_impl<0, _UElements...>&&>(__in))
899 { }
900
901 // tuple assignment
902
903 _GLIBCXX20_CONSTEXPR
904 tuple&
905 operator=(typename conditional<__assignable<const _Elements&...>(),
906 const tuple&,
907 const __nonesuch&>::type __in)
908 noexcept(__nothrow_assignable<const _Elements&...>())
909 {
910 this->_M_assign(__in);
911 return *this;
912 }
913
914 _GLIBCXX20_CONSTEXPR
915 tuple&
916 operator=(typename conditional<__assignable<_Elements...>(),
917 tuple&&,
918 __nonesuch&&>::type __in)
919 noexcept(__nothrow_assignable<_Elements...>())
920 {
921 this->_M_assign(std::move(__in));
922 return *this;
923 }
924
925 template<typename... _UElements>
926 _GLIBCXX20_CONSTEXPR
927 __enable_if_t<__assignable<const _UElements&...>(), tuple&>
928 operator=(const tuple<_UElements...>& __in)
929 noexcept(__nothrow_assignable<const _UElements&...>())
930 {
931 this->_M_assign(__in);
932 return *this;
933 }
934
935 template<typename... _UElements>
936 _GLIBCXX20_CONSTEXPR
937 __enable_if_t<__assignable<_UElements...>(), tuple&>
938 operator=(tuple<_UElements...>&& __in)
939 noexcept(__nothrow_assignable<_UElements...>())
940 {
941 this->_M_assign(std::move(__in));
942 return *this;
943 }
944
945 // tuple swap
946 _GLIBCXX20_CONSTEXPR
947 void
948 swap(tuple& __in)
949 noexcept(__and_<__is_nothrow_swappable<_Elements>...>::value)
950 { _Inherited::_M_swap(__in); }
951 };
952
953#if __cpp_deduction_guides >= 201606
954 template<typename... _UTypes>
955 tuple(_UTypes...) -> tuple<_UTypes...>;
956 template<typename _T1, typename _T2>
957 tuple(pair<_T1, _T2>) -> tuple<_T1, _T2>;
958 template<typename _Alloc, typename... _UTypes>
959 tuple(allocator_arg_t, _Alloc, _UTypes...) -> tuple<_UTypes...>;
960 template<typename _Alloc, typename _T1, typename _T2>
961 tuple(allocator_arg_t, _Alloc, pair<_T1, _T2>) -> tuple<_T1, _T2>;
962 template<typename _Alloc, typename... _UTypes>
963 tuple(allocator_arg_t, _Alloc, tuple<_UTypes...>) -> tuple<_UTypes...>;
964#endif
965
966 // Explicit specialization, zero-element tuple.
967 template<>
968 class tuple<>
969 {
970 public:
971 _GLIBCXX20_CONSTEXPR
972 void swap(tuple&) noexcept { /* no-op */ }
973 // We need the default since we're going to define no-op
974 // allocator constructors.
975 tuple() = default;
976 // No-op allocator constructors.
977 template<typename _Alloc>
978 _GLIBCXX20_CONSTEXPR
979 tuple(allocator_arg_t, const _Alloc&) noexcept { }
980 template<typename _Alloc>
981 _GLIBCXX20_CONSTEXPR
982 tuple(allocator_arg_t, const _Alloc&, const tuple&) noexcept { }
983 };
984
985 /// Partial specialization, 2-element tuple.
986 /// Includes construction and assignment from a pair.
987 template<typename _T1, typename _T2>
988 class tuple<_T1, _T2> : public _Tuple_impl<0, _T1, _T2>
989 {
990 typedef _Tuple_impl<0, _T1, _T2> _Inherited;
991
992 // Constraint for non-explicit default constructor
993 template<bool _Dummy, typename _U1, typename _U2>
994 using _ImplicitDefaultCtor = __enable_if_t<
995 _TupleConstraints<_Dummy, _U1, _U2>::
996 __is_implicitly_default_constructible(),
997 bool>;
998
999 // Constraint for explicit default constructor
1000 template<bool _Dummy, typename _U1, typename _U2>
1001 using _ExplicitDefaultCtor = __enable_if_t<
1002 _TupleConstraints<_Dummy, _U1, _U2>::
1003 __is_explicitly_default_constructible(),
1004 bool>;
1005
1006 template<bool _Dummy>
1007 using _TCC = _TupleConstraints<_Dummy, _T1, _T2>;
1008
1009 // Constraint for non-explicit constructors
1010 template<bool _Cond, typename _U1, typename _U2>
1011 using _ImplicitCtor = __enable_if_t<
1012 _TCC<_Cond>::template __is_implicitly_constructible<_U1, _U2>(),
1013 bool>;
1014
1015 // Constraint for non-explicit constructors
1016 template<bool _Cond, typename _U1, typename _U2>
1017 using _ExplicitCtor = __enable_if_t<
1018 _TCC<_Cond>::template __is_explicitly_constructible<_U1, _U2>(),
1019 bool>;
1020
1021 template<typename _U1, typename _U2>
1022 static constexpr bool __assignable()
1023 {
1024 return __and_<is_assignable<_T1&, _U1>,
1025 is_assignable<_T2&, _U2>>::value;
1026 }
1027
1028 template<typename _U1, typename _U2>
1029 static constexpr bool __nothrow_assignable()
1030 {
1031 return __and_<is_nothrow_assignable<_T1&, _U1>,
1032 is_nothrow_assignable<_T2&, _U2>>::value;
1033 }
1034
1035 template<typename _U1, typename _U2>
1036 static constexpr bool __nothrow_constructible()
1037 {
1038 return __and_<is_nothrow_constructible<_T1, _U1>,
1039 is_nothrow_constructible<_T2, _U2>>::value;
1040 }
1041
1042 static constexpr bool __nothrow_default_constructible()
1043 {
1044 return __and_<is_nothrow_default_constructible<_T1>,
1045 is_nothrow_default_constructible<_T2>>::value;
1046 }
1047
1048 template<typename _U1>
1049 static constexpr bool __is_alloc_arg()
1050 { return is_same<__remove_cvref_t<_U1>, allocator_arg_t>::value; }
1051
1052 public:
1053 template<bool _Dummy = true,
1054 _ImplicitDefaultCtor<_Dummy, _T1, _T2> = true>
1055 constexpr
1056 tuple()
1057 noexcept(__nothrow_default_constructible())
1058 : _Inherited() { }
1059
1060 template<bool _Dummy = true,
1061 _ExplicitDefaultCtor<_Dummy, _T1, _T2> = false>
1062 explicit constexpr
1063 tuple()
1064 noexcept(__nothrow_default_constructible())
1065 : _Inherited() { }
1066
1067 template<bool _Dummy = true,
1068 _ImplicitCtor<_Dummy, const _T1&, const _T2&> = true>
1069 constexpr
1070 tuple(const _T1& __a1, const _T2& __a2)
1071 noexcept(__nothrow_constructible<const _T1&, const _T2&>())
1072 : _Inherited(__a1, __a2) { }
1073
1074 template<bool _Dummy = true,
1075 _ExplicitCtor<_Dummy, const _T1&, const _T2&> = false>
1076 explicit constexpr
1077 tuple(const _T1& __a1, const _T2& __a2)
1078 noexcept(__nothrow_constructible<const _T1&, const _T2&>())
1079 : _Inherited(__a1, __a2) { }
1080
1081 template<typename _U1, typename _U2,
1082 _ImplicitCtor<!__is_alloc_arg<_U1>(), _U1, _U2> = true>
1083 constexpr
1084 tuple(_U1&& __a1, _U2&& __a2)
1085 noexcept(__nothrow_constructible<_U1, _U2>())
1086 : _Inherited(std::forward<_U1>(__a1), std::forward<_U2>(__a2)) { }
1087
1088 template<typename _U1, typename _U2,
1089 _ExplicitCtor<!__is_alloc_arg<_U1>(), _U1, _U2> = false>
1090 explicit constexpr
1091 tuple(_U1&& __a1, _U2&& __a2)
1092 noexcept(__nothrow_constructible<_U1, _U2>())
1093 : _Inherited(std::forward<_U1>(__a1), std::forward<_U2>(__a2)) { }
1094
1095 constexpr tuple(const tuple&) = default;
1096
1097 constexpr tuple(tuple&&) = default;
1098
1099 template<typename _U1, typename _U2,
1100 _ImplicitCtor<true, const _U1&, const _U2&> = true>
1101 constexpr
1102 tuple(const tuple<_U1, _U2>& __in)
1103 noexcept(__nothrow_constructible<const _U1&, const _U2&>())
1104 : _Inherited(static_cast<const _Tuple_impl<0, _U1, _U2>&>(__in)) { }
1105
1106 template<typename _U1, typename _U2,
1107 _ExplicitCtor<true, const _U1&, const _U2&> = false>
1108 explicit constexpr
1109 tuple(const tuple<_U1, _U2>& __in)
1110 noexcept(__nothrow_constructible<const _U1&, const _U2&>())
1111 : _Inherited(static_cast<const _Tuple_impl<0, _U1, _U2>&>(__in)) { }
1112
1113 template<typename _U1, typename _U2,
1114 _ImplicitCtor<true, _U1, _U2> = true>
1115 constexpr
1116 tuple(tuple<_U1, _U2>&& __in)
1117 noexcept(__nothrow_constructible<_U1, _U2>())
1118 : _Inherited(static_cast<_Tuple_impl<0, _U1, _U2>&&>(__in)) { }
1119
1120 template<typename _U1, typename _U2,
1121 _ExplicitCtor<true, _U1, _U2> = false>
1122 explicit constexpr
1123 tuple(tuple<_U1, _U2>&& __in)
1124 noexcept(__nothrow_constructible<_U1, _U2>())
1125 : _Inherited(static_cast<_Tuple_impl<0, _U1, _U2>&&>(__in)) { }
1126
1127 template<typename _U1, typename _U2,
1128 _ImplicitCtor<true, const _U1&, const _U2&> = true>
1129 constexpr
1130 tuple(const pair<_U1, _U2>& __in)
1131 noexcept(__nothrow_constructible<const _U1&, const _U2&>())
1132 : _Inherited(__in.first, __in.second) { }
1133
1134 template<typename _U1, typename _U2,
1135 _ExplicitCtor<true, const _U1&, const _U2&> = false>
1136 explicit constexpr
1137 tuple(const pair<_U1, _U2>& __in)
1138 noexcept(__nothrow_constructible<const _U1&, const _U2&>())
1139 : _Inherited(__in.first, __in.second) { }
1140
1141 template<typename _U1, typename _U2,
1142 _ImplicitCtor<true, _U1, _U2> = true>
1143 constexpr
1144 tuple(pair<_U1, _U2>&& __in)
1145 noexcept(__nothrow_constructible<_U1, _U2>())
1146 : _Inherited(std::forward<_U1>(__in.first),
1147 std::forward<_U2>(__in.second)) { }
1148
1149 template<typename _U1, typename _U2,
1150 _ExplicitCtor<true, _U1, _U2> = false>
1151 explicit constexpr
1152 tuple(pair<_U1, _U2>&& __in)
1153 noexcept(__nothrow_constructible<_U1, _U2>())
1154 : _Inherited(std::forward<_U1>(__in.first),
1155 std::forward<_U2>(__in.second)) { }
1156
1157 // Allocator-extended constructors.
1158
1159 template<typename _Alloc,
1160 _ImplicitDefaultCtor<is_object<_Alloc>::value, _T1, _T2> = true>
1161 _GLIBCXX20_CONSTEXPR
1162 tuple(allocator_arg_t __tag, const _Alloc& __a)
1163 : _Inherited(__tag, __a) { }
1164
1165 template<typename _Alloc,
1166 _ExplicitDefaultCtor<is_object<_Alloc>::value, _T1, _T2> = false>
1167 _GLIBCXX20_CONSTEXPR
1168 explicit
1169 tuple(allocator_arg_t __tag, const _Alloc& __a)
1170 : _Inherited(__tag, __a) { }
1171
1172 template<typename _Alloc, bool _Dummy = true,
1173 _ImplicitCtor<_Dummy, const _T1&, const _T2&> = true>
1174 _GLIBCXX20_CONSTEXPR
1175 tuple(allocator_arg_t __tag, const _Alloc& __a,
1176 const _T1& __a1, const _T2& __a2)
1177 : _Inherited(__tag, __a, __a1, __a2) { }
1178
1179 template<typename _Alloc, bool _Dummy = true,
1180 _ExplicitCtor<_Dummy, const _T1&, const _T2&> = false>
1181 explicit
1182 _GLIBCXX20_CONSTEXPR
1183 tuple(allocator_arg_t __tag, const _Alloc& __a,
1184 const _T1& __a1, const _T2& __a2)
1185 : _Inherited(__tag, __a, __a1, __a2) { }
1186
1187 template<typename _Alloc, typename _U1, typename _U2,
1188 _ImplicitCtor<true, _U1, _U2> = true>
1189 _GLIBCXX20_CONSTEXPR
1190 tuple(allocator_arg_t __tag, const _Alloc& __a, _U1&& __a1, _U2&& __a2)
1191 : _Inherited(__tag, __a, std::forward<_U1>(__a1),
1192 std::forward<_U2>(__a2)) { }
1193
1194 template<typename _Alloc, typename _U1, typename _U2,
1195 _ExplicitCtor<true, _U1, _U2> = false>
1196 explicit
1197 _GLIBCXX20_CONSTEXPR
1198 tuple(allocator_arg_t __tag, const _Alloc& __a,
1199 _U1&& __a1, _U2&& __a2)
1200 : _Inherited(__tag, __a, std::forward<_U1>(__a1),
1201 std::forward<_U2>(__a2)) { }
1202
1203 template<typename _Alloc>
1204 _GLIBCXX20_CONSTEXPR
1205 tuple(allocator_arg_t __tag, const _Alloc& __a, const tuple& __in)
1206 : _Inherited(__tag, __a, static_cast<const _Inherited&>(__in)) { }
1207
1208 template<typename _Alloc>
1209 _GLIBCXX20_CONSTEXPR
1210 tuple(allocator_arg_t __tag, const _Alloc& __a, tuple&& __in)
1211 : _Inherited(__tag, __a, static_cast<_Inherited&&>(__in)) { }
1212
1213 template<typename _Alloc, typename _U1, typename _U2,
1214 _ImplicitCtor<true, const _U1&, const _U2&> = true>
1215 _GLIBCXX20_CONSTEXPR
1216 tuple(allocator_arg_t __tag, const _Alloc& __a,
1217 const tuple<_U1, _U2>& __in)
1218 : _Inherited(__tag, __a,
1219 static_cast<const _Tuple_impl<0, _U1, _U2>&>(__in))
1220 { }
1221
1222 template<typename _Alloc, typename _U1, typename _U2,
1223 _ExplicitCtor<true, const _U1&, const _U2&> = false>
1224 explicit
1225 _GLIBCXX20_CONSTEXPR
1226 tuple(allocator_arg_t __tag, const _Alloc& __a,
1227 const tuple<_U1, _U2>& __in)
1228 : _Inherited(__tag, __a,
1229 static_cast<const _Tuple_impl<0, _U1, _U2>&>(__in))
1230 { }
1231
1232 template<typename _Alloc, typename _U1, typename _U2,
1233 _ImplicitCtor<true, _U1, _U2> = true>
1234 _GLIBCXX20_CONSTEXPR
1235 tuple(allocator_arg_t __tag, const _Alloc& __a, tuple<_U1, _U2>&& __in)
1236 : _Inherited(__tag, __a, static_cast<_Tuple_impl<0, _U1, _U2>&&>(__in))
1237 { }
1238
1239 template<typename _Alloc, typename _U1, typename _U2,
1240 _ExplicitCtor<true, _U1, _U2> = false>
1241 explicit
1242 _GLIBCXX20_CONSTEXPR
1243 tuple(allocator_arg_t __tag, const _Alloc& __a, tuple<_U1, _U2>&& __in)
1244 : _Inherited(__tag, __a, static_cast<_Tuple_impl<0, _U1, _U2>&&>(__in))
1245 { }
1246
1247 template<typename _Alloc, typename _U1, typename _U2,
1248 _ImplicitCtor<true, const _U1&, const _U2&> = true>
1249 _GLIBCXX20_CONSTEXPR
1250 tuple(allocator_arg_t __tag, const _Alloc& __a,
1251 const pair<_U1, _U2>& __in)
1252 : _Inherited(__tag, __a, __in.first, __in.second) { }
1253
1254 template<typename _Alloc, typename _U1, typename _U2,
1255 _ExplicitCtor<true, const _U1&, const _U2&> = false>
1256 explicit
1257 _GLIBCXX20_CONSTEXPR
1258 tuple(allocator_arg_t __tag, const _Alloc& __a,
1259 const pair<_U1, _U2>& __in)
1260 : _Inherited(__tag, __a, __in.first, __in.second) { }
1261
1262 template<typename _Alloc, typename _U1, typename _U2,
1263 _ImplicitCtor<true, _U1, _U2> = true>
1264 _GLIBCXX20_CONSTEXPR
1265 tuple(allocator_arg_t __tag, const _Alloc& __a, pair<_U1, _U2>&& __in)
1266 : _Inherited(__tag, __a, std::forward<_U1>(__in.first),
1267 std::forward<_U2>(__in.second)) { }
1268
1269 template<typename _Alloc, typename _U1, typename _U2,
1270 _ExplicitCtor<true, _U1, _U2> = false>
1271 explicit
1272 _GLIBCXX20_CONSTEXPR
1273 tuple(allocator_arg_t __tag, const _Alloc& __a, pair<_U1, _U2>&& __in)
1274 : _Inherited(__tag, __a, std::forward<_U1>(__in.first),
1275 std::forward<_U2>(__in.second)) { }
1276
1277 // Tuple assignment.
1278
1279 _GLIBCXX20_CONSTEXPR
1280 tuple&
1281 operator=(typename conditional<__assignable<const _T1&, const _T2&>(),
1282 const tuple&,
1283 const __nonesuch&>::type __in)
1284 noexcept(__nothrow_assignable<const _T1&, const _T2&>())
1285 {
1286 this->_M_assign(__in);
1287 return *this;
1288 }
1289
1290 _GLIBCXX20_CONSTEXPR
1291 tuple&
1292 operator=(typename conditional<__assignable<_T1, _T2>(),
1293 tuple&&,
1294 __nonesuch&&>::type __in)
1295 noexcept(__nothrow_assignable<_T1, _T2>())
1296 {
1297 this->_M_assign(std::move(__in));
1298 return *this;
1299 }
1300
1301 template<typename _U1, typename _U2>
1302 _GLIBCXX20_CONSTEXPR
1303 __enable_if_t<__assignable<const _U1&, const _U2&>(), tuple&>
1304 operator=(const tuple<_U1, _U2>& __in)
1305 noexcept(__nothrow_assignable<const _U1&, const _U2&>())
1306 {
1307 this->_M_assign(__in);
1308 return *this;
1309 }
1310
1311 template<typename _U1, typename _U2>
1312 _GLIBCXX20_CONSTEXPR
1313 __enable_if_t<__assignable<_U1, _U2>(), tuple&>
1314 operator=(tuple<_U1, _U2>&& __in)
1315 noexcept(__nothrow_assignable<_U1, _U2>())
1316 {
1317 this->_M_assign(std::move(__in));
1318 return *this;
1319 }
1320
1321 template<typename _U1, typename _U2>
1322 _GLIBCXX20_CONSTEXPR
1323 __enable_if_t<__assignable<const _U1&, const _U2&>(), tuple&>
1324 operator=(const pair<_U1, _U2>& __in)
1325 noexcept(__nothrow_assignable<const _U1&, const _U2&>())
1326 {
1327 this->_M_head(*this) = __in.first;
1328 this->_M_tail(*this)._M_head(*this) = __in.second;
1329 return *this;
1330 }
1331
1332 template<typename _U1, typename _U2>
1333 _GLIBCXX20_CONSTEXPR
1334 __enable_if_t<__assignable<_U1, _U2>(), tuple&>
1335 operator=(pair<_U1, _U2>&& __in)
1336 noexcept(__nothrow_assignable<_U1, _U2>())
1337 {
1338 this->_M_head(*this) = std::forward<_U1>(__in.first);
1339 this->_M_tail(*this)._M_head(*this) = std::forward<_U2>(__in.second);
1340 return *this;
1341 }
1342
1343 _GLIBCXX20_CONSTEXPR
1344 void
1345 swap(tuple& __in)
1346 noexcept(__and_<__is_nothrow_swappable<_T1>,
1347 __is_nothrow_swappable<_T2>>::value)
1348 { _Inherited::_M_swap(__in); }
1349 };
1350
1351
1352 /// class tuple_size
1353 template<typename... _Elements>
1354 struct tuple_size<tuple<_Elements...>>
1355 : public integral_constant<size_t, sizeof...(_Elements)> { };
1356
1357#if __cplusplus > 201402L
1358 template <typename _Tp>
1359 inline constexpr size_t tuple_size_v = tuple_size<_Tp>::value;
1360#endif
1361
1362 /**
1363 * Recursive case for tuple_element: strip off the first element in
1364 * the tuple and retrieve the (i-1)th element of the remaining tuple.
1365 */
1366 template<size_t __i, typename _Head, typename... _Tail>
1367 struct tuple_element<__i, tuple<_Head, _Tail...> >
1368 : tuple_element<__i - 1, tuple<_Tail...> > { };
1369
1370 /**
1371 * Basis case for tuple_element: The first element is the one we're seeking.
1372 */
1373 template<typename _Head, typename... _Tail>
1374 struct tuple_element<0, tuple<_Head, _Tail...> >
1375 {
1376 typedef _Head type;
1377 };
1378
1379 /**
1380 * Error case for tuple_element: invalid index.
1381 */
1382 template<size_t __i>
1383 struct tuple_element<__i, tuple<>>
1384 {
1385 static_assert(__i < tuple_size<tuple<>>::value,
1386 "tuple index must be in range");
1387 };
1388
1389 template<size_t __i, typename _Head, typename... _Tail>
1390 constexpr _Head&
1391 __get_helper(_Tuple_impl<__i, _Head, _Tail...>& __t) noexcept
1392 { return _Tuple_impl<__i, _Head, _Tail...>::_M_head(__t); }
1393
1394 template<size_t __i, typename _Head, typename... _Tail>
1395 constexpr const _Head&
1396 __get_helper(const _Tuple_impl<__i, _Head, _Tail...>& __t) noexcept
1397 { return _Tuple_impl<__i, _Head, _Tail...>::_M_head(__t); }
1398
1399 // Deleted overload to improve diagnostics for invalid indices
1400 template<size_t __i, typename... _Types>
1401 __enable_if_t<(__i >= sizeof...(_Types))>
1402 __get_helper(const tuple<_Types...>&) = delete;
1403
1404 /// Return a reference to the ith element of a tuple.
1405 template<size_t __i, typename... _Elements>
1406 constexpr __tuple_element_t<__i, tuple<_Elements...>>&
1407 get(tuple<_Elements...>& __t) noexcept
1408 { return std::__get_helper<__i>(__t); }
1409
1410 /// Return a const reference to the ith element of a const tuple.
1411 template<size_t __i, typename... _Elements>
1412 constexpr const __tuple_element_t<__i, tuple<_Elements...>>&
1413 get(const tuple<_Elements...>& __t) noexcept
1414 { return std::__get_helper<__i>(__t); }
1415
1416 /// Return an rvalue reference to the ith element of a tuple rvalue.
1417 template<size_t __i, typename... _Elements>
1418 constexpr __tuple_element_t<__i, tuple<_Elements...>>&&
1419 get(tuple<_Elements...>&& __t) noexcept
1420 {
1421 typedef __tuple_element_t<__i, tuple<_Elements...>> __element_type;
1422 return std::forward<__element_type>(std::__get_helper<__i>(__t));
1423 }
1424
1425 /// Return a const rvalue reference to the ith element of a const tuple rvalue.
1426 template<size_t __i, typename... _Elements>
1427 constexpr const __tuple_element_t<__i, tuple<_Elements...>>&&
1428 get(const tuple<_Elements...>&& __t) noexcept
1429 {
1430 typedef __tuple_element_t<__i, tuple<_Elements...>> __element_type;
1431 return std::forward<const __element_type>(std::__get_helper<__i>(__t));
1432 }
1433
1434#if __cplusplus >= 201402L
1435
1436#define __cpp_lib_tuples_by_type 201304
1437
1438 // Return the index of _Tp in _Types, if it occurs exactly once.
1439 // Otherwise, return sizeof...(_Types).
1440 // TODO reuse this for __detail::__variant::__exactly_once.
1441 template<typename _Tp, typename... _Types>
1442 constexpr size_t
1443 __find_uniq_type_in_pack()
1444 {
1445 constexpr size_t __sz = sizeof...(_Types);
1446 constexpr bool __found[__sz] = { __is_same(_Tp, _Types) ... };
1447 size_t __n = __sz;
1448 for (size_t __i = 0; __i < __sz; ++__i)
1449 {
1450 if (__found[__i])
1451 {
1452 if (__n < __sz) // more than one _Tp found
1453 return __sz;
1454 __n = __i;
1455 }
1456 }
1457 return __n;
1458 }
1459
1460 /// Return a reference to the unique element of type _Tp of a tuple.
1461 template <typename _Tp, typename... _Types>
1462 constexpr _Tp&
1463 get(tuple<_Types...>& __t) noexcept
1464 {
1465 constexpr size_t __idx = __find_uniq_type_in_pack<_Tp, _Types...>();
1466 static_assert(__idx < sizeof...(_Types),
1467 "the type T in std::get<T> must occur exactly once in the tuple");
1468 return std::__get_helper<__idx>(__t);
1469 }
1470
1471 /// Return a reference to the unique element of type _Tp of a tuple rvalue.
1472 template <typename _Tp, typename... _Types>
1473 constexpr _Tp&&
1474 get(tuple<_Types...>&& __t) noexcept
1475 {
1476 constexpr size_t __idx = __find_uniq_type_in_pack<_Tp, _Types...>();
1477 static_assert(__idx < sizeof...(_Types),
1478 "the type T in std::get<T> must occur exactly once in the tuple");
1479 return std::forward<_Tp>(std::__get_helper<__idx>(__t));
1480 }
1481
1482 /// Return a const reference to the unique element of type _Tp of a tuple.
1483 template <typename _Tp, typename... _Types>
1484 constexpr const _Tp&
1485 get(const tuple<_Types...>& __t) noexcept
1486 {
1487 constexpr size_t __idx = __find_uniq_type_in_pack<_Tp, _Types...>();
1488 static_assert(__idx < sizeof...(_Types),
1489 "the type T in std::get<T> must occur exactly once in the tuple");
1490 return std::__get_helper<__idx>(__t);
1491 }
1492
1493 /// Return a const reference to the unique element of type _Tp of
1494 /// a const tuple rvalue.
1495 template <typename _Tp, typename... _Types>
1496 constexpr const _Tp&&
1497 get(const tuple<_Types...>&& __t) noexcept
1498 {
1499 constexpr size_t __idx = __find_uniq_type_in_pack<_Tp, _Types...>();
1500 static_assert(__idx < sizeof...(_Types),
1501 "the type T in std::get<T> must occur exactly once in the tuple");
1502 return std::forward<const _Tp>(std::__get_helper<__idx>(__t));
1503 }
1504#endif
1505
1506 // This class performs the comparison operations on tuples
1507 template<typename _Tp, typename _Up, size_t __i, size_t __size>
1508 struct __tuple_compare
1509 {
1510 static constexpr bool
1511 __eq(const _Tp& __t, const _Up& __u)
1512 {
1513 return bool(std::get<__i>(__t) == std::get<__i>(__u))
1514 && __tuple_compare<_Tp, _Up, __i + 1, __size>::__eq(__t, __u);
1515 }
1516
1517 static constexpr bool
1518 __less(const _Tp& __t, const _Up& __u)
1519 {
1520 return bool(std::get<__i>(__t) < std::get<__i>(__u))
1521 || (!bool(std::get<__i>(__u) < std::get<__i>(__t))
1522 && __tuple_compare<_Tp, _Up, __i + 1, __size>::__less(__t, __u));
1523 }
1524 };
1525
1526 template<typename _Tp, typename _Up, size_t __size>
1527 struct __tuple_compare<_Tp, _Up, __size, __size>
1528 {
1529 static constexpr bool
1530 __eq(const _Tp&, const _Up&) { return true; }
1531
1532 static constexpr bool
1533 __less(const _Tp&, const _Up&) { return false; }
1534 };
1535
1536 template<typename... _TElements, typename... _UElements>
1537 constexpr bool
1538 operator==(const tuple<_TElements...>& __t,
1539 const tuple<_UElements...>& __u)
1540 {
1541 static_assert(sizeof...(_TElements) == sizeof...(_UElements),
1542 "tuple objects can only be compared if they have equal sizes.");
1543 using __compare = __tuple_compare<tuple<_TElements...>,
1544 tuple<_UElements...>,
1545 0, sizeof...(_TElements)>;
1546 return __compare::__eq(__t, __u);
1547 }
1548
1549#if __cpp_lib_three_way_comparison
1550 template<typename _Cat, typename _Tp, typename _Up>
1551 constexpr _Cat
1552 __tuple_cmp(const _Tp&, const _Up&, index_sequence<>)
1553 { return _Cat::equivalent; }
1554
1555 template<typename _Cat, typename _Tp, typename _Up,
1556 size_t _Idx0, size_t... _Idxs>
1557 constexpr _Cat
1558 __tuple_cmp(const _Tp& __t, const _Up& __u,
1559 index_sequence<_Idx0, _Idxs...>)
1560 {
1561 auto __c
1562 = __detail::__synth3way(std::get<_Idx0>(__t), std::get<_Idx0>(__u));
1563 if (__c != 0)
1564 return __c;
1565 return std::__tuple_cmp<_Cat>(__t, __u, index_sequence<_Idxs...>());
1566 }
1567
1568 template<typename... _Tps, typename... _Ups>
1569 constexpr
1570 common_comparison_category_t<__detail::__synth3way_t<_Tps, _Ups>...>
1571 operator<=>(const tuple<_Tps...>& __t, const tuple<_Ups...>& __u)
1572 {
1573 using _Cat
1574 = common_comparison_category_t<__detail::__synth3way_t<_Tps, _Ups>...>;
1575 return std::__tuple_cmp<_Cat>(__t, __u, index_sequence_for<_Tps...>());
1576 }
1577#else
1578 template<typename... _TElements, typename... _UElements>
1579 constexpr bool
1580 operator<(const tuple<_TElements...>& __t,
1581 const tuple<_UElements...>& __u)
1582 {
1583 static_assert(sizeof...(_TElements) == sizeof...(_UElements),
1584 "tuple objects can only be compared if they have equal sizes.");
1585 using __compare = __tuple_compare<tuple<_TElements...>,
1586 tuple<_UElements...>,
1587 0, sizeof...(_TElements)>;
1588 return __compare::__less(__t, __u);
1589 }
1590
1591 template<typename... _TElements, typename... _UElements>
1592 constexpr bool
1593 operator!=(const tuple<_TElements...>& __t,
1594 const tuple<_UElements...>& __u)
1595 { return !(__t == __u); }
1596
1597 template<typename... _TElements, typename... _UElements>
1598 constexpr bool
1599 operator>(const tuple<_TElements...>& __t,
1600 const tuple<_UElements...>& __u)
1601 { return __u < __t; }
1602
1603 template<typename... _TElements, typename... _UElements>
1604 constexpr bool
1605 operator<=(const tuple<_TElements...>& __t,
1606 const tuple<_UElements...>& __u)
1607 { return !(__u < __t); }
1608
1609 template<typename... _TElements, typename... _UElements>
1610 constexpr bool
1611 operator>=(const tuple<_TElements...>& __t,
1612 const tuple<_UElements...>& __u)
1613 { return !(__t < __u); }
1614#endif // three_way_comparison
1615
1616 // NB: DR 705.
1617 template<typename... _Elements>
1618 constexpr tuple<typename __decay_and_strip<_Elements>::__type...>
1619 make_tuple(_Elements&&... __args)
1620 {
1621 typedef tuple<typename __decay_and_strip<_Elements>::__type...>
1622 __result_type;
1623 return __result_type(std::forward<_Elements>(__args)...);
1624 }
1625
1626 // _GLIBCXX_RESOLVE_LIB_DEFECTS
1627 // 2275. Why is forward_as_tuple not constexpr?
1628 /// std::forward_as_tuple
1629 template<typename... _Elements>
1630 constexpr tuple<_Elements&&...>
1631 forward_as_tuple(_Elements&&... __args) noexcept
1632 { return tuple<_Elements&&...>(std::forward<_Elements>(__args)...); }
1633
1634 template<size_t, typename, typename, size_t>
1635 struct __make_tuple_impl;
1636
1637 template<size_t _Idx, typename _Tuple, typename... _Tp, size_t _Nm>
1638 struct __make_tuple_impl<_Idx, tuple<_Tp...>, _Tuple, _Nm>
1639 : __make_tuple_impl<_Idx + 1,
1640 tuple<_Tp..., __tuple_element_t<_Idx, _Tuple>>,
1641 _Tuple, _Nm>
1642 { };
1643
1644 template<size_t _Nm, typename _Tuple, typename... _Tp>
1645 struct __make_tuple_impl<_Nm, tuple<_Tp...>, _Tuple, _Nm>
1646 {
1647 typedef tuple<_Tp...> __type;
1648 };
1649
1650 template<typename _Tuple>
1651 struct __do_make_tuple
1652 : __make_tuple_impl<0, tuple<>, _Tuple, tuple_size<_Tuple>::value>
1653 { };
1654
1655 // Returns the std::tuple equivalent of a tuple-like type.
1656 template<typename _Tuple>
1657 struct __make_tuple
1658 : public __do_make_tuple<__remove_cvref_t<_Tuple>>
1659 { };
1660
1661 // Combines several std::tuple's into a single one.
1662 template<typename...>
1663 struct __combine_tuples;
1664
1665 template<>
1666 struct __combine_tuples<>
1667 {
1668 typedef tuple<> __type;
1669 };
1670
1671 template<typename... _Ts>
1672 struct __combine_tuples<tuple<_Ts...>>
1673 {
1674 typedef tuple<_Ts...> __type;
1675 };
1676
1677 template<typename... _T1s, typename... _T2s, typename... _Rem>
1678 struct __combine_tuples<tuple<_T1s...>, tuple<_T2s...>, _Rem...>
1679 {
1680 typedef typename __combine_tuples<tuple<_T1s..., _T2s...>,
1681 _Rem...>::__type __type;
1682 };
1683
1684 // Computes the result type of tuple_cat given a set of tuple-like types.
1685 template<typename... _Tpls>
1686 struct __tuple_cat_result
1687 {
1688 typedef typename __combine_tuples
1689 <typename __make_tuple<_Tpls>::__type...>::__type __type;
1690 };
1691
1692 // Helper to determine the index set for the first tuple-like
1693 // type of a given set.
1694 template<typename...>
1695 struct __make_1st_indices;
1696
1697 template<>
1698 struct __make_1st_indices<>
1699 {
1700 typedef _Index_tuple<> __type;
1701 };
1702
1703 template<typename _Tp, typename... _Tpls>
1704 struct __make_1st_indices<_Tp, _Tpls...>
1705 {
1706 typedef typename _Build_index_tuple<tuple_size<
1707 typename remove_reference<_Tp>::type>::value>::__type __type;
1708 };
1709
1710 // Performs the actual concatenation by step-wise expanding tuple-like
1711 // objects into the elements, which are finally forwarded into the
1712 // result tuple.
1713 template<typename _Ret, typename _Indices, typename... _Tpls>
1714 struct __tuple_concater;
1715
1716 template<typename _Ret, size_t... _Is, typename _Tp, typename... _Tpls>
1717 struct __tuple_concater<_Ret, _Index_tuple<_Is...>, _Tp, _Tpls...>
1718 {
1719 template<typename... _Us>
1720 static constexpr _Ret
1721 _S_do(_Tp&& __tp, _Tpls&&... __tps, _Us&&... __us)
1722 {
1723 typedef typename __make_1st_indices<_Tpls...>::__type __idx;
1724 typedef __tuple_concater<_Ret, __idx, _Tpls...> __next;
1725 return __next::_S_do(std::forward<_Tpls>(__tps)...,
1726 std::forward<_Us>(__us)...,
1727 std::get<_Is>(std::forward<_Tp>(__tp))...);
1728 }
1729 };
1730
1731 template<typename _Ret>
1732 struct __tuple_concater<_Ret, _Index_tuple<>>
1733 {
1734 template<typename... _Us>
1735 static constexpr _Ret
1736 _S_do(_Us&&... __us)
1737 {
1738 return _Ret(std::forward<_Us>(__us)...);
1739 }
1740 };
1741
1742 /// tuple_cat
1743 template<typename... _Tpls, typename = typename
1744 enable_if<__and_<__is_tuple_like<_Tpls>...>::value>::type>
1745 constexpr auto
1746 tuple_cat(_Tpls&&... __tpls)
1747 -> typename __tuple_cat_result<_Tpls...>::__type
1748 {
1749 typedef typename __tuple_cat_result<_Tpls...>::__type __ret;
1750 typedef typename __make_1st_indices<_Tpls...>::__type __idx;
1751 typedef __tuple_concater<__ret, __idx, _Tpls...> __concater;
1752 return __concater::_S_do(std::forward<_Tpls>(__tpls)...);
1753 }
1754
1755 // _GLIBCXX_RESOLVE_LIB_DEFECTS
1756 // 2301. Why is tie not constexpr?
1757 /// tie
1758 template<typename... _Elements>
1759 constexpr tuple<_Elements&...>
1760 tie(_Elements&... __args) noexcept
1761 { return tuple<_Elements&...>(__args...); }
1762
1763 /// swap
1764 template<typename... _Elements>
1765 _GLIBCXX20_CONSTEXPR
1766 inline
1767#if __cplusplus > 201402L || !defined(__STRICT_ANSI__) // c++1z or gnu++11
1768 // Constrained free swap overload, see p0185r1
1769 typename enable_if<__and_<__is_swappable<_Elements>...>::value
1770 >::type
1771#else
1772 void
1773#endif
1774 swap(tuple<_Elements...>& __x, tuple<_Elements...>& __y)
1775 noexcept(noexcept(__x.swap(__y)))
1776 { __x.swap(__y); }
1777
1778#if __cplusplus > 201402L || !defined(__STRICT_ANSI__) // c++1z or gnu++11
1779 template<typename... _Elements>
1780 _GLIBCXX20_CONSTEXPR
1781 typename enable_if<!__and_<__is_swappable<_Elements>...>::value>::type
1782 swap(tuple<_Elements...>&, tuple<_Elements...>&) = delete;
1783#endif
1784
1785 // A class (and instance) which can be used in 'tie' when an element
1786 // of a tuple is not required.
1787 // _GLIBCXX14_CONSTEXPR
1788 // 2933. PR for LWG 2773 could be clearer
1789 struct _Swallow_assign
1790 {
1791 template<class _Tp>
1792 _GLIBCXX14_CONSTEXPR const _Swallow_assign&
1793 operator=(const _Tp&) const
1794 { return *this; }
1795 };
1796
1797 // _GLIBCXX_RESOLVE_LIB_DEFECTS
1798 // 2773. Making std::ignore constexpr
1799 _GLIBCXX17_INLINE constexpr _Swallow_assign ignore{};
1800
1801 /// Partial specialization for tuples
1802 template<typename... _Types, typename _Alloc>
1803 struct uses_allocator<tuple<_Types...>, _Alloc> : true_type { };
1804
1805 // See stl_pair.h...
1806 /** "piecewise construction" using a tuple of arguments for each member.
1807 *
1808 * @param __first Arguments for the first member of the pair.
1809 * @param __second Arguments for the second member of the pair.
1810 *
1811 * The elements of each tuple will be used as the constructor arguments
1812 * for the data members of the pair.
1813 */
1814 template<class _T1, class _T2>
1815 template<typename... _Args1, typename... _Args2>
1816 _GLIBCXX20_CONSTEXPR
1817 inline
1818 pair<_T1, _T2>::
1819 pair(piecewise_construct_t,
1820 tuple<_Args1...> __first, tuple<_Args2...> __second)
1821 : pair(__first, __second,
1822 typename _Build_index_tuple<sizeof...(_Args1)>::__type(),
1823 typename _Build_index_tuple<sizeof...(_Args2)>::__type())
1824 { }
1825
1826 template<class _T1, class _T2>
1827 template<typename... _Args1, size_t... _Indexes1,
1828 typename... _Args2, size_t... _Indexes2>
1829 _GLIBCXX20_CONSTEXPR inline
1830 pair<_T1, _T2>::
1831 pair(tuple<_Args1...>& __tuple1, tuple<_Args2...>& __tuple2,
1832 _Index_tuple<_Indexes1...>, _Index_tuple<_Indexes2...>)
1833 : first(std::forward<_Args1>(std::get<_Indexes1>(__tuple1))...),
1834 second(std::forward<_Args2>(std::get<_Indexes2>(__tuple2))...)
1835 { }
1836
1837#if __cplusplus >= 201703L
1838
1839 // Unpack a std::tuple into a type trait and use its value.
1840 // For cv std::tuple<_Up> the result is _Trait<_Tp, cv _Up...>::value.
1841 // For cv std::tuple<_Up>& the result is _Trait<_Tp, cv _Up&...>::value.
1842 // Otherwise the result is false (because we don't know if std::get throws).
1843 template<template<typename...> class _Trait, typename _Tp, typename _Tuple>
1844 inline constexpr bool __unpack_std_tuple = false;
1845
1846 template<template<typename...> class _Trait, typename _Tp, typename... _Up>
1847 inline constexpr bool __unpack_std_tuple<_Trait, _Tp, tuple<_Up...>>
1848 = _Trait<_Tp, _Up...>::value;
1849
1850 template<template<typename...> class _Trait, typename _Tp, typename... _Up>
1851 inline constexpr bool __unpack_std_tuple<_Trait, _Tp, tuple<_Up...>&>
1852 = _Trait<_Tp, _Up&...>::value;
1853
1854 template<template<typename...> class _Trait, typename _Tp, typename... _Up>
1855 inline constexpr bool __unpack_std_tuple<_Trait, _Tp, const tuple<_Up...>>
1856 = _Trait<_Tp, const _Up...>::value;
1857
1858 template<template<typename...> class _Trait, typename _Tp, typename... _Up>
1859 inline constexpr bool __unpack_std_tuple<_Trait, _Tp, const tuple<_Up...>&>
1860 = _Trait<_Tp, const _Up&...>::value;
1861
1862# define __cpp_lib_apply 201603
1863
1864 template <typename _Fn, typename _Tuple, size_t... _Idx>
1865 constexpr decltype(auto)
1866 __apply_impl(_Fn&& __f, _Tuple&& __t, index_sequence<_Idx...>)
1867 {
1868 return std::__invoke(std::forward<_Fn>(__f),
1869 std::get<_Idx>(std::forward<_Tuple>(__t))...);
1870 }
1871
1872 template <typename _Fn, typename _Tuple>
1873 constexpr decltype(auto)
1874 apply(_Fn&& __f, _Tuple&& __t)
1875 noexcept(__unpack_std_tuple<is_nothrow_invocable, _Fn, _Tuple>)
1876 {
1877 using _Indices
1878 = make_index_sequence<tuple_size_v<remove_reference_t<_Tuple>>>;
1879 return std::__apply_impl(std::forward<_Fn>(__f),
1880 std::forward<_Tuple>(__t),
1881 _Indices{});
1882 }
1883
1884#define __cpp_lib_make_from_tuple 201606
1885
1886 template <typename _Tp, typename _Tuple, size_t... _Idx>
1887 constexpr _Tp
1888 __make_from_tuple_impl(_Tuple&& __t, index_sequence<_Idx...>)
1889 { return _Tp(std::get<_Idx>(std::forward<_Tuple>(__t))...); }
1890
1891 template <typename _Tp, typename _Tuple>
1892 constexpr _Tp
1893 make_from_tuple(_Tuple&& __t)
1894 noexcept(__unpack_std_tuple<is_nothrow_constructible, _Tp, _Tuple>)
1895 {
1896 return __make_from_tuple_impl<_Tp>(
1897 std::forward<_Tuple>(__t),
1898 make_index_sequence<tuple_size_v<remove_reference_t<_Tuple>>>{});
1899 }
1900#endif // C++17
1901
1902 /// @}
1903
1904_GLIBCXX_END_NAMESPACE_VERSION
1905} // namespace std
1906
1907#endif // C++11
1908
1909#endif // _GLIBCXX_TUPLE
std::remove_reference_t
typename remove_reference< _Tp >::type remove_reference_t
Alias template for remove_reference.
Definition type_traits:1637
std::true_type
integral_constant< bool, true > true_type
The type used as a compile-time boolean with true value.
Definition type_traits:83
std::false_type
integral_constant< bool, false > false_type
The type used as a compile-time boolean with false value.
Definition type_traits:86
std::tuple_cat
constexpr auto tuple_cat(_Tpls &&... __tpls) -> typename __tuple_cat_result< _Tpls... >::__type
tuple_cat
Definition tuple:1745
std::forward_as_tuple
constexpr tuple< _Elements &&... > forward_as_tuple(_Elements &&... __args) noexcept
std::forward_as_tuple
Definition tuple:1630
std::move
constexpr std::remove_reference< _Tp >::type && move(_Tp &&__t) noexcept
Convert a value to an rvalue.
Definition move.h:104
std::__invoke
constexpr __invoke_result< _Callable, _Args... >::type __invoke(_Callable &&__fn, _Args &&... __args) noexcept(__is_nothrow_invocable< _Callable, _Args... >::value)
Invoke a callable object.
Definition invoke.h:90
std::tie
constexpr tuple< _Elements &... > tie(_Elements &... __args) noexcept
tie
Definition tuple:1759
std::swap
void swap(any &__x, any &__y) noexcept
Exchange the states of two any objects.
Definition any:428
std::forward
constexpr _Tp && forward(typename std::remove_reference< _Tp >::type &__t) noexcept
Forward an lvalue.
Definition move.h:77
std
ISO C++ entities toplevel namespace is std.
std::make_index_sequence
make_integer_sequence< size_t, _Num > make_index_sequence
Alias template make_index_sequence.
Definition utility:339
std::index_sequence
integer_sequence< size_t, _Idx... > index_sequence
Alias template index_sequence.
Definition utility:335
std::index_sequence_for
make_index_sequence< sizeof...(_Types)> index_sequence_for
Alias template index_sequence_for.
Definition utility:343
std::tuple_size
tuple_size
Definition array:433
std::tuple_element
tuple_element
Definition array:442
std::tuple
Primary class template, tuple.
Definition tuple:609
std::integral_constant
integral_constant
Definition type_traits:66
std::conditional
Define a member typedef type to one of two argument types.
Definition type_traits:2219
std::is_empty
is_empty
Definition type_traits:757
std::is_nothrow_constructible
is_nothrow_constructible
Definition type_traits:1024
std::is_nothrow_default_constructible
is_nothrow_default_constructible
Definition type_traits:1033
std::is_assignable
is_assignable
Definition type_traits:1088
std::is_nothrow_assignable
is_nothrow_assignable
Definition type_traits:1142
std::enable_if
Define a member typedef type only if a boolean constant is true.
Definition type_traits:2192
std::uses_allocator
Declare uses_allocator so it can be specialized in <queue> etc.
Definition memoryfwd.h:72
std::piecewise_construct_t
Tag type for piecewise construction of std::pair objects.
Definition stl_pair.h:80
std::pair
Struct holding two objects of arbitrary type.
Definition stl_pair.h:213
std::pair::pair
constexpr pair()
Definition stl_pair.h:232