1 // List implementation -*- C++ -*-
2
3 // Copyright (C) 2001-2020 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 bits/stl_list.h
52 * This is an internal header file, included by other library headers.
53 * Do not attempt to use it directly. @headername{list}
54 */
55
56 #ifndef _STL_LIST_H
57 #define _STL_LIST_H 1
58
59 #include <bits/concept_check.h>
60 #include <ext/alloc_traits.h>
61 #if __cplusplus >= 201103L
62 #include <initializer_list>
63 #include <bits/allocated_ptr.h>
64 #include <ext/aligned_buffer.h>
65 #endif
66
_GLIBCXX_VISIBILITY(default)67 namespace std _GLIBCXX_VISIBILITY(default)
68 {
69 _GLIBCXX_BEGIN_NAMESPACE_VERSION
70
71 namespace __detail
72 {
73 // Supporting structures are split into common and templated
74 // types; the latter publicly inherits from the former in an
75 // effort to reduce code duplication. This results in some
76 // "needless" static_cast'ing later on, but it's all safe
77 // downcasting.
78
79 /// Common part of a node in the %list.
80 struct _List_node_base
81 {
82 _List_node_base* _M_next;
83 _List_node_base* _M_prev;
84
85 static void
86 swap(_List_node_base& __x, _List_node_base& __y) _GLIBCXX_USE_NOEXCEPT;
87
88 void
89 _M_transfer(_List_node_base* const __first,
90 _List_node_base* const __last) _GLIBCXX_USE_NOEXCEPT;
91
92 void
93 _M_reverse() _GLIBCXX_USE_NOEXCEPT;
94
95 void
96 _M_hook(_List_node_base* const __position) _GLIBCXX_USE_NOEXCEPT;
97
98 void
99 _M_unhook() _GLIBCXX_USE_NOEXCEPT;
100 };
101
102 /// The %list node header.
103 struct _List_node_header : public _List_node_base
104 {
105 #if _GLIBCXX_USE_CXX11_ABI
106 std::size_t _M_size;
107 #endif
108
109 _List_node_header() _GLIBCXX_NOEXCEPT
110 { _M_init(); }
111
112 #if __cplusplus >= 201103L
113 _List_node_header(_List_node_header&& __x) noexcept
114 : _List_node_base{ __x._M_next, __x._M_prev }
115 # if _GLIBCXX_USE_CXX11_ABI
116 , _M_size(__x._M_size)
117 # endif
118 {
119 if (__x._M_base()->_M_next == __x._M_base())
120 this->_M_next = this->_M_prev = this;
121 else
122 {
123 this->_M_next->_M_prev = this->_M_prev->_M_next = this->_M_base();
124 __x._M_init();
125 }
126 }
127
128 void
129 _M_move_nodes(_List_node_header&& __x)
130 {
131 _List_node_base* const __xnode = __x._M_base();
132 if (__xnode->_M_next == __xnode)
133 _M_init();
134 else
135 {
136 _List_node_base* const __node = this->_M_base();
137 __node->_M_next = __xnode->_M_next;
138 __node->_M_prev = __xnode->_M_prev;
139 __node->_M_next->_M_prev = __node->_M_prev->_M_next = __node;
140 # if _GLIBCXX_USE_CXX11_ABI
141 _M_size = __x._M_size;
142 # endif
143 __x._M_init();
144 }
145 }
146 #endif
147
148 void
149 _M_init() _GLIBCXX_NOEXCEPT
150 {
151 this->_M_next = this->_M_prev = this;
152 #if _GLIBCXX_USE_CXX11_ABI
153 this->_M_size = 0;
154 #endif
155 }
156
157 private:
158 _List_node_base* _M_base() { return this; }
159 };
160 } // namespace detail
161
162 _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
163
164 /// An actual node in the %list.
165 template<typename _Tp>
166 struct _List_node : public __detail::_List_node_base
167 {
168 #if __cplusplus >= 201103L
169 __gnu_cxx::__aligned_membuf<_Tp> _M_storage;
170 _Tp* _M_valptr() { return _M_storage._M_ptr(); }
171 _Tp const* _M_valptr() const { return _M_storage._M_ptr(); }
172 #else
173 _Tp _M_data;
174 _Tp* _M_valptr() { return std::__addressof(_M_data); }
175 _Tp const* _M_valptr() const { return std::__addressof(_M_data); }
176 #endif
177 };
178
179 /**
180 * @brief A list::iterator.
181 *
182 * All the functions are op overloads.
183 */
184 template<typename _Tp>
185 struct _List_iterator
186 {
187 typedef _List_iterator<_Tp> _Self;
188 typedef _List_node<_Tp> _Node;
189
190 typedef ptrdiff_t difference_type;
191 typedef std::bidirectional_iterator_tag iterator_category;
192 typedef _Tp value_type;
193 typedef _Tp* pointer;
194 typedef _Tp& reference;
195
196 _List_iterator() _GLIBCXX_NOEXCEPT
197 : _M_node() { }
198
199 explicit
200 _List_iterator(__detail::_List_node_base* __x) _GLIBCXX_NOEXCEPT
201 : _M_node(__x) { }
202
203 _Self
204 _M_const_cast() const _GLIBCXX_NOEXCEPT
205 { return *this; }
206
207 // Must downcast from _List_node_base to _List_node to get to value.
208 reference
209 operator*() const _GLIBCXX_NOEXCEPT
210 { return *static_cast<_Node*>(_M_node)->_M_valptr(); }
211
212 pointer
213 operator->() const _GLIBCXX_NOEXCEPT
214 { return static_cast<_Node*>(_M_node)->_M_valptr(); }
215
216 _Self&
217 operator++() _GLIBCXX_NOEXCEPT
218 {
219 _M_node = _M_node->_M_next;
220 return *this;
221 }
222
223 _Self
224 operator++(int) _GLIBCXX_NOEXCEPT
225 {
226 _Self __tmp = *this;
227 _M_node = _M_node->_M_next;
228 return __tmp;
229 }
230
231 _Self&
232 operator--() _GLIBCXX_NOEXCEPT
233 {
234 _M_node = _M_node->_M_prev;
235 return *this;
236 }
237
238 _Self
239 operator--(int) _GLIBCXX_NOEXCEPT
240 {
241 _Self __tmp = *this;
242 _M_node = _M_node->_M_prev;
243 return __tmp;
244 }
245
246 friend bool
247 operator==(const _Self& __x, const _Self& __y) _GLIBCXX_NOEXCEPT
248 { return __x._M_node == __y._M_node; }
249
250 #if __cpp_impl_three_way_comparison < 201907L
251 friend bool
252 operator!=(const _Self& __x, const _Self& __y) _GLIBCXX_NOEXCEPT
253 { return __x._M_node != __y._M_node; }
254 #endif
255
256 // The only member points to the %list element.
257 __detail::_List_node_base* _M_node;
258 };
259
260 /**
261 * @brief A list::const_iterator.
262 *
263 * All the functions are op overloads.
264 */
265 template<typename _Tp>
266 struct _List_const_iterator
267 {
268 typedef _List_const_iterator<_Tp> _Self;
269 typedef const _List_node<_Tp> _Node;
270 typedef _List_iterator<_Tp> iterator;
271
272 typedef ptrdiff_t difference_type;
273 typedef std::bidirectional_iterator_tag iterator_category;
274 typedef _Tp value_type;
275 typedef const _Tp* pointer;
276 typedef const _Tp& reference;
277
278 _List_const_iterator() _GLIBCXX_NOEXCEPT
279 : _M_node() { }
280
281 explicit
282 _List_const_iterator(const __detail::_List_node_base* __x)
283 _GLIBCXX_NOEXCEPT
284 : _M_node(__x) { }
285
286 _List_const_iterator(const iterator& __x) _GLIBCXX_NOEXCEPT
287 : _M_node(__x._M_node) { }
288
289 iterator
290 _M_const_cast() const _GLIBCXX_NOEXCEPT
291 { return iterator(const_cast<__detail::_List_node_base*>(_M_node)); }
292
293 // Must downcast from List_node_base to _List_node to get to value.
294 reference
295 operator*() const _GLIBCXX_NOEXCEPT
296 { return *static_cast<_Node*>(_M_node)->_M_valptr(); }
297
298 pointer
299 operator->() const _GLIBCXX_NOEXCEPT
300 { return static_cast<_Node*>(_M_node)->_M_valptr(); }
301
302 _Self&
303 operator++() _GLIBCXX_NOEXCEPT
304 {
305 _M_node = _M_node->_M_next;
306 return *this;
307 }
308
309 _Self
310 operator++(int) _GLIBCXX_NOEXCEPT
311 {
312 _Self __tmp = *this;
313 _M_node = _M_node->_M_next;
314 return __tmp;
315 }
316
317 _Self&
318 operator--() _GLIBCXX_NOEXCEPT
319 {
320 _M_node = _M_node->_M_prev;
321 return *this;
322 }
323
324 _Self
325 operator--(int) _GLIBCXX_NOEXCEPT
326 {
327 _Self __tmp = *this;
328 _M_node = _M_node->_M_prev;
329 return __tmp;
330 }
331
332 friend bool
333 operator==(const _Self& __x, const _Self& __y) _GLIBCXX_NOEXCEPT
334 { return __x._M_node == __y._M_node; }
335
336 #if __cpp_impl_three_way_comparison < 201907L
337 friend bool
338 operator!=(const _Self& __x, const _Self& __y) _GLIBCXX_NOEXCEPT
339 { return __x._M_node != __y._M_node; }
340 #endif
341
342 // The only member points to the %list element.
343 const __detail::_List_node_base* _M_node;
344 };
345
346 _GLIBCXX_BEGIN_NAMESPACE_CXX11
347 /// See bits/stl_deque.h's _Deque_base for an explanation.
348 template<typename _Tp, typename _Alloc>
349 class _List_base
350 {
351 protected:
352 typedef typename __gnu_cxx::__alloc_traits<_Alloc>::template
353 rebind<_Tp>::other _Tp_alloc_type;
354 typedef __gnu_cxx::__alloc_traits<_Tp_alloc_type> _Tp_alloc_traits;
355 typedef typename _Tp_alloc_traits::template
356 rebind<_List_node<_Tp> >::other _Node_alloc_type;
357 typedef __gnu_cxx::__alloc_traits<_Node_alloc_type> _Node_alloc_traits;
358
359 #if !_GLIBCXX_INLINE_VERSION
360 static size_t
361 _S_distance(const __detail::_List_node_base* __first,
362 const __detail::_List_node_base* __last)
363 {
364 size_t __n = 0;
365 while (__first != __last)
366 {
367 __first = __first->_M_next;
368 ++__n;
369 }
370 return __n;
371 }
372 #endif
373
374 struct _List_impl
375 : public _Node_alloc_type
376 {
377 __detail::_List_node_header _M_node;
378
379 _List_impl() _GLIBCXX_NOEXCEPT_IF(
380 is_nothrow_default_constructible<_Node_alloc_type>::value)
381 : _Node_alloc_type()
382 { }
383
384 _List_impl(const _Node_alloc_type& __a) _GLIBCXX_NOEXCEPT
385 : _Node_alloc_type(__a)
386 { }
387
388 #if __cplusplus >= 201103L
389 _List_impl(_List_impl&&) = default;
390
391 _List_impl(_Node_alloc_type&& __a, _List_impl&& __x)
392 : _Node_alloc_type(std::move(__a)), _M_node(std::move(__x._M_node))
393 { }
394
395 _List_impl(_Node_alloc_type&& __a) noexcept
396 : _Node_alloc_type(std::move(__a))
397 { }
398 #endif
399 };
400
401 _List_impl _M_impl;
402
403 #if _GLIBCXX_USE_CXX11_ABI
404 size_t _M_get_size() const { return _M_impl._M_node._M_size; }
405
406 void _M_set_size(size_t __n) { _M_impl._M_node._M_size = __n; }
407
408 void _M_inc_size(size_t __n) { _M_impl._M_node._M_size += __n; }
409
410 void _M_dec_size(size_t __n) { _M_impl._M_node._M_size -= __n; }
411
412 # if !_GLIBCXX_INLINE_VERSION
413 size_t
414 _M_distance(const __detail::_List_node_base* __first,
415 const __detail::_List_node_base* __last) const
416 { return _S_distance(__first, __last); }
417
418 // return the stored size
419 size_t _M_node_count() const { return _M_get_size(); }
420 # endif
421 #else
422 // dummy implementations used when the size is not stored
423 size_t _M_get_size() const { return 0; }
424 void _M_set_size(size_t) { }
425 void _M_inc_size(size_t) { }
426 void _M_dec_size(size_t) { }
427
428 # if !_GLIBCXX_INLINE_VERSION
429 size_t _M_distance(const void*, const void*) const { return 0; }
430
431 // count the number of nodes
432 size_t _M_node_count() const
433 {
434 return _S_distance(_M_impl._M_node._M_next,
435 std::__addressof(_M_impl._M_node));
436 }
437 # endif
438 #endif
439
440 typename _Node_alloc_traits::pointer
441 _M_get_node()
442 { return _Node_alloc_traits::allocate(_M_impl, 1); }
443
444 void
445 _M_put_node(typename _Node_alloc_traits::pointer __p) _GLIBCXX_NOEXCEPT
446 { _Node_alloc_traits::deallocate(_M_impl, __p, 1); }
447
448 public:
449 typedef _Alloc allocator_type;
450
451 _Node_alloc_type&
452 _M_get_Node_allocator() _GLIBCXX_NOEXCEPT
453 { return _M_impl; }
454
455 const _Node_alloc_type&
456 _M_get_Node_allocator() const _GLIBCXX_NOEXCEPT
457 { return _M_impl; }
458
459 #if __cplusplus >= 201103L
460 _List_base() = default;
461 #else
462 _List_base() { }
463 #endif
464
465 _List_base(const _Node_alloc_type& __a) _GLIBCXX_NOEXCEPT
466 : _M_impl(__a)
467 { }
468
469 #if __cplusplus >= 201103L
470 _List_base(_List_base&&) = default;
471
472 # if !_GLIBCXX_INLINE_VERSION
473 _List_base(_List_base&& __x, _Node_alloc_type&& __a)
474 : _M_impl(std::move(__a))
475 {
476 if (__x._M_get_Node_allocator() == _M_get_Node_allocator())
477 _M_move_nodes(std::move(__x));
478 // else caller must move individual elements.
479 }
480 # endif
481
482 // Used when allocator is_always_equal.
483 _List_base(_Node_alloc_type&& __a, _List_base&& __x)
484 : _M_impl(std::move(__a), std::move(__x._M_impl))
485 { }
486
487 // Used when allocator !is_always_equal.
488 _List_base(_Node_alloc_type&& __a)
489 : _M_impl(std::move(__a))
490 { }
491
492 void
493 _M_move_nodes(_List_base&& __x)
494 { _M_impl._M_node._M_move_nodes(std::move(__x._M_impl._M_node)); }
495 #endif
496
497 // This is what actually destroys the list.
498 ~_List_base() _GLIBCXX_NOEXCEPT
499 { _M_clear(); }
500
501 void
502 _M_clear() _GLIBCXX_NOEXCEPT;
503
504 void
505 _M_init() _GLIBCXX_NOEXCEPT
506 { this->_M_impl._M_node._M_init(); }
507 };
508
509 /**
510 * @brief A standard container with linear time access to elements,
511 * and fixed time insertion/deletion at any point in the sequence.
512 *
513 * @ingroup sequences
514 *
515 * @tparam _Tp Type of element.
516 * @tparam _Alloc Allocator type, defaults to allocator<_Tp>.
517 *
518 * Meets the requirements of a <a href="tables.html#65">container</a>, a
519 * <a href="tables.html#66">reversible container</a>, and a
520 * <a href="tables.html#67">sequence</a>, including the
521 * <a href="tables.html#68">optional sequence requirements</a> with the
522 * %exception of @c at and @c operator[].
523 *
524 * This is a @e doubly @e linked %list. Traversal up and down the
525 * %list requires linear time, but adding and removing elements (or
526 * @e nodes) is done in constant time, regardless of where the
527 * change takes place. Unlike std::vector and std::deque,
528 * random-access iterators are not provided, so subscripting ( @c
529 * [] ) access is not allowed. For algorithms which only need
530 * sequential access, this lack makes no difference.
531 *
532 * Also unlike the other standard containers, std::list provides
533 * specialized algorithms %unique to linked lists, such as
534 * splicing, sorting, and in-place reversal.
535 *
536 * A couple points on memory allocation for list<Tp>:
537 *
538 * First, we never actually allocate a Tp, we allocate
539 * List_node<Tp>'s and trust [20.1.5]/4 to DTRT. This is to ensure
540 * that after elements from %list<X,Alloc1> are spliced into
541 * %list<X,Alloc2>, destroying the memory of the second %list is a
542 * valid operation, i.e., Alloc1 giveth and Alloc2 taketh away.
543 *
544 * Second, a %list conceptually represented as
545 * @code
546 * A <---> B <---> C <---> D
547 * @endcode
548 * is actually circular; a link exists between A and D. The %list
549 * class holds (as its only data member) a private list::iterator
550 * pointing to @e D, not to @e A! To get to the head of the %list,
551 * we start at the tail and move forward by one. When this member
552 * iterator's next/previous pointers refer to itself, the %list is
553 * %empty.
554 */
555 template<typename _Tp, typename _Alloc = std::allocator<_Tp> >
556 class list : protected _List_base<_Tp, _Alloc>
557 {
558 #ifdef _GLIBCXX_CONCEPT_CHECKS
559 // concept requirements
560 typedef typename _Alloc::value_type _Alloc_value_type;
561 # if __cplusplus < 201103L
562 __glibcxx_class_requires(_Tp, _SGIAssignableConcept)
563 # endif
564 __glibcxx_class_requires2(_Tp, _Alloc_value_type, _SameTypeConcept)
565 #endif
566
567 #if __cplusplus >= 201103L
568 static_assert(is_same<typename remove_cv<_Tp>::type, _Tp>::value,
569 "std::list must have a non-const, non-volatile value_type");
570 # if __cplusplus > 201703L || defined __STRICT_ANSI__
571 static_assert(is_same<typename _Alloc::value_type, _Tp>::value,
572 "std::list must have the same value_type as its allocator");
573 # endif
574 #endif
575
576 typedef _List_base<_Tp, _Alloc> _Base;
577 typedef typename _Base::_Tp_alloc_type _Tp_alloc_type;
578 typedef typename _Base::_Tp_alloc_traits _Tp_alloc_traits;
579 typedef typename _Base::_Node_alloc_type _Node_alloc_type;
580 typedef typename _Base::_Node_alloc_traits _Node_alloc_traits;
581
582 public:
583 typedef _Tp value_type;
584 typedef typename _Tp_alloc_traits::pointer pointer;
585 typedef typename _Tp_alloc_traits::const_pointer const_pointer;
586 typedef typename _Tp_alloc_traits::reference reference;
587 typedef typename _Tp_alloc_traits::const_reference const_reference;
588 typedef _List_iterator<_Tp> iterator;
589 typedef _List_const_iterator<_Tp> const_iterator;
590 typedef std::reverse_iterator<const_iterator> const_reverse_iterator;
591 typedef std::reverse_iterator<iterator> reverse_iterator;
592 typedef size_t size_type;
593 typedef ptrdiff_t difference_type;
594 typedef _Alloc allocator_type;
595
596 protected:
597 // Note that pointers-to-_Node's can be ctor-converted to
598 // iterator types.
599 typedef _List_node<_Tp> _Node;
600
601 using _Base::_M_impl;
602 using _Base::_M_put_node;
603 using _Base::_M_get_node;
604 using _Base::_M_get_Node_allocator;
605
606 /**
607 * @param __args An instance of user data.
608 *
609 * Allocates space for a new node and constructs a copy of
610 * @a __args in it.
611 */
612 #if __cplusplus < 201103L
613 _Node*
614 _M_create_node(const value_type& __x)
615 {
616 _Node* __p = this->_M_get_node();
617 __try
618 {
619 _Tp_alloc_type __alloc(_M_get_Node_allocator());
620 __alloc.construct(__p->_M_valptr(), __x);
621 }
622 __catch(...)
623 {
624 _M_put_node(__p);
625 __throw_exception_again;
626 }
627 return __p;
628 }
629 #else
630 template<typename... _Args>
631 _Node*
632 _M_create_node(_Args&&... __args)
633 {
634 auto __p = this->_M_get_node();
635 auto& __alloc = _M_get_Node_allocator();
636 __allocated_ptr<_Node_alloc_type> __guard{__alloc, __p};
637 _Node_alloc_traits::construct(__alloc, __p->_M_valptr(),
638 std::forward<_Args>(__args)...);
639 __guard = nullptr;
640 return __p;
641 }
642 #endif
643
644 #if _GLIBCXX_USE_CXX11_ABI
645 static size_t
646 _S_distance(const_iterator __first, const_iterator __last)
647 { return std::distance(__first, __last); }
648
649 // return the stored size
650 size_t
651 _M_node_count() const
652 { return this->_M_get_size(); }
653 #else
654 // dummy implementations used when the size is not stored
655 static size_t
656 _S_distance(const_iterator, const_iterator)
657 { return 0; }
658
659 // count the number of nodes
660 size_t
661 _M_node_count() const
662 { return std::distance(begin(), end()); }
663 #endif
664
665 public:
666 // [23.2.2.1] construct/copy/destroy
667 // (assign() and get_allocator() are also listed in this section)
668
669 /**
670 * @brief Creates a %list with no elements.
671 */
672 #if __cplusplus >= 201103L
673 list() = default;
674 #else
675 list() { }
676 #endif
677
678 /**
679 * @brief Creates a %list with no elements.
680 * @param __a An allocator object.
681 */
682 explicit
683 list(const allocator_type& __a) _GLIBCXX_NOEXCEPT
684 : _Base(_Node_alloc_type(__a)) { }
685
686 #if __cplusplus >= 201103L
687 /**
688 * @brief Creates a %list with default constructed elements.
689 * @param __n The number of elements to initially create.
690 * @param __a An allocator object.
691 *
692 * This constructor fills the %list with @a __n default
693 * constructed elements.
694 */
695 explicit
696 list(size_type __n, const allocator_type& __a = allocator_type())
697 : _Base(_Node_alloc_type(__a))
698 { _M_default_initialize(__n); }
699
700 /**
701 * @brief Creates a %list with copies of an exemplar element.
702 * @param __n The number of elements to initially create.
703 * @param __value An element to copy.
704 * @param __a An allocator object.
705 *
706 * This constructor fills the %list with @a __n copies of @a __value.
707 */
708 list(size_type __n, const value_type& __value,
709 const allocator_type& __a = allocator_type())
710 : _Base(_Node_alloc_type(__a))
711 { _M_fill_initialize(__n, __value); }
712 #else
713 /**
714 * @brief Creates a %list with copies of an exemplar element.
715 * @param __n The number of elements to initially create.
716 * @param __value An element to copy.
717 * @param __a An allocator object.
718 *
719 * This constructor fills the %list with @a __n copies of @a __value.
720 */
721 explicit
722 list(size_type __n, const value_type& __value = value_type(),
723 const allocator_type& __a = allocator_type())
724 : _Base(_Node_alloc_type(__a))
725 { _M_fill_initialize(__n, __value); }
726 #endif
727
728 /**
729 * @brief %List copy constructor.
730 * @param __x A %list of identical element and allocator types.
731 *
732 * The newly-created %list uses a copy of the allocation object used
733 * by @a __x (unless the allocator traits dictate a different object).
734 */
735 list(const list& __x)
736 : _Base(_Node_alloc_traits::
737 _S_select_on_copy(__x._M_get_Node_allocator()))
738 { _M_initialize_dispatch(__x.begin(), __x.end(), __false_type()); }
739
740 #if __cplusplus >= 201103L
741 /**
742 * @brief %List move constructor.
743 *
744 * The newly-created %list contains the exact contents of the moved
745 * instance. The contents of the moved instance are a valid, but
746 * unspecified %list.
747 */
748 list(list&&) = default;
749
750 /**
751 * @brief Builds a %list from an initializer_list
752 * @param __l An initializer_list of value_type.
753 * @param __a An allocator object.
754 *
755 * Create a %list consisting of copies of the elements in the
756 * initializer_list @a __l. This is linear in __l.size().
757 */
758 list(initializer_list<value_type> __l,
759 const allocator_type& __a = allocator_type())
760 : _Base(_Node_alloc_type(__a))
761 { _M_initialize_dispatch(__l.begin(), __l.end(), __false_type()); }
762
763 list(const list& __x, const allocator_type& __a)
764 : _Base(_Node_alloc_type(__a))
765 { _M_initialize_dispatch(__x.begin(), __x.end(), __false_type()); }
766
767 private:
768 list(list&& __x, const allocator_type& __a, true_type) noexcept
769 : _Base(_Node_alloc_type(__a), std::move(__x))
770 { }
771
772 list(list&& __x, const allocator_type& __a, false_type)
773 : _Base(_Node_alloc_type(__a))
774 {
775 if (__x._M_get_Node_allocator() == this->_M_get_Node_allocator())
776 this->_M_move_nodes(std::move(__x));
777 else
778 insert(begin(), std::__make_move_if_noexcept_iterator(__x.begin()),
779 std::__make_move_if_noexcept_iterator(__x.end()));
780 }
781
782 public:
783 list(list&& __x, const allocator_type& __a)
784 noexcept(_Node_alloc_traits::_S_always_equal())
785 : list(std::move(__x), __a,
786 typename _Node_alloc_traits::is_always_equal{})
787 { }
788 #endif
789
790 /**
791 * @brief Builds a %list from a range.
792 * @param __first An input iterator.
793 * @param __last An input iterator.
794 * @param __a An allocator object.
795 *
796 * Create a %list consisting of copies of the elements from
797 * [@a __first,@a __last). This is linear in N (where N is
798 * distance(@a __first,@a __last)).
799 */
800 #if __cplusplus >= 201103L
801 template<typename _InputIterator,
802 typename = std::_RequireInputIter<_InputIterator>>
803 list(_InputIterator __first, _InputIterator __last,
804 const allocator_type& __a = allocator_type())
805 : _Base(_Node_alloc_type(__a))
806 { _M_initialize_dispatch(__first, __last, __false_type()); }
807 #else
808 template<typename _InputIterator>
809 list(_InputIterator __first, _InputIterator __last,
810 const allocator_type& __a = allocator_type())
811 : _Base(_Node_alloc_type(__a))
812 {
813 // Check whether it's an integral type. If so, it's not an iterator.
814 typedef typename std::__is_integer<_InputIterator>::__type _Integral;
815 _M_initialize_dispatch(__first, __last, _Integral());
816 }
817 #endif
818
819 #if __cplusplus >= 201103L
820 /**
821 * No explicit dtor needed as the _Base dtor takes care of
822 * things. The _Base dtor only erases the elements, and note
823 * that if the elements themselves are pointers, the pointed-to
824 * memory is not touched in any way. Managing the pointer is
825 * the user's responsibility.
826 */
827 ~list() = default;
828 #endif
829
830 /**
831 * @brief %List assignment operator.
832 * @param __x A %list of identical element and allocator types.
833 *
834 * All the elements of @a __x are copied.
835 *
836 * Whether the allocator is copied depends on the allocator traits.
837 */
838 list&
839 operator=(const list& __x);
840
841 #if __cplusplus >= 201103L
842 /**
843 * @brief %List move assignment operator.
844 * @param __x A %list of identical element and allocator types.
845 *
846 * The contents of @a __x are moved into this %list (without copying).
847 *
848 * Afterwards @a __x is a valid, but unspecified %list
849 *
850 * Whether the allocator is moved depends on the allocator traits.
851 */
852 list&
853 operator=(list&& __x)
854 noexcept(_Node_alloc_traits::_S_nothrow_move())
855 {
856 constexpr bool __move_storage =
857 _Node_alloc_traits::_S_propagate_on_move_assign()
858 || _Node_alloc_traits::_S_always_equal();
859 _M_move_assign(std::move(__x), __bool_constant<__move_storage>());
860 return *this;
861 }
862
863 /**
864 * @brief %List initializer list assignment operator.
865 * @param __l An initializer_list of value_type.
866 *
867 * Replace the contents of the %list with copies of the elements
868 * in the initializer_list @a __l. This is linear in l.size().
869 */
870 list&
871 operator=(initializer_list<value_type> __l)
872 {
873 this->assign(__l.begin(), __l.end());
874 return *this;
875 }
876 #endif
877
878 /**
879 * @brief Assigns a given value to a %list.
880 * @param __n Number of elements to be assigned.
881 * @param __val Value to be assigned.
882 *
883 * This function fills a %list with @a __n copies of the given
884 * value. Note that the assignment completely changes the %list
885 * and that the resulting %list's size is the same as the number
886 * of elements assigned.
887 */
888 void
889 assign(size_type __n, const value_type& __val)
890 { _M_fill_assign(__n, __val); }
891
892 /**
893 * @brief Assigns a range to a %list.
894 * @param __first An input iterator.
895 * @param __last An input iterator.
896 *
897 * This function fills a %list with copies of the elements in the
898 * range [@a __first,@a __last).
899 *
900 * Note that the assignment completely changes the %list and
901 * that the resulting %list's size is the same as the number of
902 * elements assigned.
903 */
904 #if __cplusplus >= 201103L
905 template<typename _InputIterator,
906 typename = std::_RequireInputIter<_InputIterator>>
907 void
908 assign(_InputIterator __first, _InputIterator __last)
909 { _M_assign_dispatch(__first, __last, __false_type()); }
910 #else
911 template<typename _InputIterator>
912 void
913 assign(_InputIterator __first, _InputIterator __last)
914 {
915 // Check whether it's an integral type. If so, it's not an iterator.
916 typedef typename std::__is_integer<_InputIterator>::__type _Integral;
917 _M_assign_dispatch(__first, __last, _Integral());
918 }
919 #endif
920
921 #if __cplusplus >= 201103L
922 /**
923 * @brief Assigns an initializer_list to a %list.
924 * @param __l An initializer_list of value_type.
925 *
926 * Replace the contents of the %list with copies of the elements
927 * in the initializer_list @a __l. This is linear in __l.size().
928 */
929 void
930 assign(initializer_list<value_type> __l)
931 { this->_M_assign_dispatch(__l.begin(), __l.end(), __false_type()); }
932 #endif
933
934 /// Get a copy of the memory allocation object.
935 allocator_type
936 get_allocator() const _GLIBCXX_NOEXCEPT
937 { return allocator_type(_Base::_M_get_Node_allocator()); }
938
939 // iterators
940 /**
941 * Returns a read/write iterator that points to the first element in the
942 * %list. Iteration is done in ordinary element order.
943 */
944 iterator
945 begin() _GLIBCXX_NOEXCEPT
946 { return iterator(this->_M_impl._M_node._M_next); }
947
948 /**
949 * Returns a read-only (constant) iterator that points to the
950 * first element in the %list. Iteration is done in ordinary
951 * element order.
952 */
953 const_iterator
954 begin() const _GLIBCXX_NOEXCEPT
955 { return const_iterator(this->_M_impl._M_node._M_next); }
956
957 /**
958 * Returns a read/write iterator that points one past the last
959 * element in the %list. Iteration is done in ordinary element
960 * order.
961 */
962 iterator
963 end() _GLIBCXX_NOEXCEPT
964 { return iterator(&this->_M_impl._M_node); }
965
966 /**
967 * Returns a read-only (constant) iterator that points one past
968 * the last element in the %list. Iteration is done in ordinary
969 * element order.
970 */
971 const_iterator
972 end() const _GLIBCXX_NOEXCEPT
973 { return const_iterator(&this->_M_impl._M_node); }
974
975 /**
976 * Returns a read/write reverse iterator that points to the last
977 * element in the %list. Iteration is done in reverse element
978 * order.
979 */
980 reverse_iterator
981 rbegin() _GLIBCXX_NOEXCEPT
982 { return reverse_iterator(end()); }
983
984 /**
985 * Returns a read-only (constant) reverse iterator that points to
986 * the last element in the %list. Iteration is done in reverse
987 * element order.
988 */
989 const_reverse_iterator
990 rbegin() const _GLIBCXX_NOEXCEPT
991 { return const_reverse_iterator(end()); }
992
993 /**
994 * Returns a read/write reverse iterator that points to one
995 * before the first element in the %list. Iteration is done in
996 * reverse element order.
997 */
998 reverse_iterator
999 rend() _GLIBCXX_NOEXCEPT
1000 { return reverse_iterator(begin()); }
1001
1002 /**
1003 * Returns a read-only (constant) reverse iterator that points to one
1004 * before the first element in the %list. Iteration is done in reverse
1005 * element order.
1006 */
1007 const_reverse_iterator
1008 rend() const _GLIBCXX_NOEXCEPT
1009 { return const_reverse_iterator(begin()); }
1010
1011 #if __cplusplus >= 201103L
1012 /**
1013 * Returns a read-only (constant) iterator that points to the
1014 * first element in the %list. Iteration is done in ordinary
1015 * element order.
1016 */
1017 const_iterator
1018 cbegin() const noexcept
1019 { return const_iterator(this->_M_impl._M_node._M_next); }
1020
1021 /**
1022 * Returns a read-only (constant) iterator that points one past
1023 * the last element in the %list. Iteration is done in ordinary
1024 * element order.
1025 */
1026 const_iterator
1027 cend() const noexcept
1028 { return const_iterator(&this->_M_impl._M_node); }
1029
1030 /**
1031 * Returns a read-only (constant) reverse iterator that points to
1032 * the last element in the %list. Iteration is done in reverse
1033 * element order.
1034 */
1035 const_reverse_iterator
1036 crbegin() const noexcept
1037 { return const_reverse_iterator(end()); }
1038
1039 /**
1040 * Returns a read-only (constant) reverse iterator that points to one
1041 * before the first element in the %list. Iteration is done in reverse
1042 * element order.
1043 */
1044 const_reverse_iterator
1045 crend() const noexcept
1046 { return const_reverse_iterator(begin()); }
1047 #endif
1048
1049 // [23.2.2.2] capacity
1050 /**
1051 * Returns true if the %list is empty. (Thus begin() would equal
1052 * end().)
1053 */
1054 _GLIBCXX_NODISCARD bool
1055 empty() const _GLIBCXX_NOEXCEPT
1056 { return this->_M_impl._M_node._M_next == &this->_M_impl._M_node; }
1057
1058 /** Returns the number of elements in the %list. */
1059 size_type
1060 size() const _GLIBCXX_NOEXCEPT
1061 { return _M_node_count(); }
1062
1063 /** Returns the size() of the largest possible %list. */
1064 size_type
1065 max_size() const _GLIBCXX_NOEXCEPT
1066 { return _Node_alloc_traits::max_size(_M_get_Node_allocator()); }
1067
1068 #if __cplusplus >= 201103L
1069 /**
1070 * @brief Resizes the %list to the specified number of elements.
1071 * @param __new_size Number of elements the %list should contain.
1072 *
1073 * This function will %resize the %list to the specified number
1074 * of elements. If the number is smaller than the %list's
1075 * current size the %list is truncated, otherwise default
1076 * constructed elements are appended.
1077 */
1078 void
1079 resize(size_type __new_size);
1080
1081 /**
1082 * @brief Resizes the %list to the specified number of elements.
1083 * @param __new_size Number of elements the %list should contain.
1084 * @param __x Data with which new elements should be populated.
1085 *
1086 * This function will %resize the %list to the specified number
1087 * of elements. If the number is smaller than the %list's
1088 * current size the %list is truncated, otherwise the %list is
1089 * extended and new elements are populated with given data.
1090 */
1091 void
1092 resize(size_type __new_size, const value_type& __x);
1093 #else
1094 /**
1095 * @brief Resizes the %list to the specified number of elements.
1096 * @param __new_size Number of elements the %list should contain.
1097 * @param __x Data with which new elements should be populated.
1098 *
1099 * This function will %resize the %list to the specified number
1100 * of elements. If the number is smaller than the %list's
1101 * current size the %list is truncated, otherwise the %list is
1102 * extended and new elements are populated with given data.
1103 */
1104 void
1105 resize(size_type __new_size, value_type __x = value_type());
1106 #endif
1107
1108 // element access
1109 /**
1110 * Returns a read/write reference to the data at the first
1111 * element of the %list.
1112 */
1113 reference
1114 front() _GLIBCXX_NOEXCEPT
1115 { return *begin(); }
1116
1117 /**
1118 * Returns a read-only (constant) reference to the data at the first
1119 * element of the %list.
1120 */
1121 const_reference
1122 front() const _GLIBCXX_NOEXCEPT
1123 { return *begin(); }
1124
1125 /**
1126 * Returns a read/write reference to the data at the last element
1127 * of the %list.
1128 */
1129 reference
1130 back() _GLIBCXX_NOEXCEPT
1131 {
1132 iterator __tmp = end();
1133 --__tmp;
1134 return *__tmp;
1135 }
1136
1137 /**
1138 * Returns a read-only (constant) reference to the data at the last
1139 * element of the %list.
1140 */
1141 const_reference
1142 back() const _GLIBCXX_NOEXCEPT
1143 {
1144 const_iterator __tmp = end();
1145 --__tmp;
1146 return *__tmp;
1147 }
1148
1149 // [23.2.2.3] modifiers
1150 /**
1151 * @brief Add data to the front of the %list.
1152 * @param __x Data to be added.
1153 *
1154 * This is a typical stack operation. The function creates an
1155 * element at the front of the %list and assigns the given data
1156 * to it. Due to the nature of a %list this operation can be
1157 * done in constant time, and does not invalidate iterators and
1158 * references.
1159 */
1160 void
1161 push_front(const value_type& __x)
1162 { this->_M_insert(begin(), __x); }
1163
1164 #if __cplusplus >= 201103L
1165 void
1166 push_front(value_type&& __x)
1167 { this->_M_insert(begin(), std::move(__x)); }
1168
1169 template<typename... _Args>
1170 #if __cplusplus > 201402L
1171 reference
1172 #else
1173 void
1174 #endif
1175 emplace_front(_Args&&... __args)
1176 {
1177 this->_M_insert(begin(), std::forward<_Args>(__args)...);
1178 #if __cplusplus > 201402L
1179 return front();
1180 #endif
1181 }
1182 #endif
1183
1184 /**
1185 * @brief Removes first element.
1186 *
1187 * This is a typical stack operation. It shrinks the %list by
1188 * one. Due to the nature of a %list this operation can be done
1189 * in constant time, and only invalidates iterators/references to
1190 * the element being removed.
1191 *
1192 * Note that no data is returned, and if the first element's data
1193 * is needed, it should be retrieved before pop_front() is
1194 * called.
1195 */
1196 void
1197 pop_front() _GLIBCXX_NOEXCEPT
1198 { this->_M_erase(begin()); }
1199
1200 /**
1201 * @brief Add data to the end of the %list.
1202 * @param __x Data to be added.
1203 *
1204 * This is a typical stack operation. The function creates an
1205 * element at the end of the %list and assigns the given data to
1206 * it. Due to the nature of a %list this operation can be done
1207 * in constant time, and does not invalidate iterators and
1208 * references.
1209 */
1210 void
1211 push_back(const value_type& __x)
1212 { this->_M_insert(end(), __x); }
1213
1214 #if __cplusplus >= 201103L
1215 void
1216 push_back(value_type&& __x)
1217 { this->_M_insert(end(), std::move(__x)); }
1218
1219 template<typename... _Args>
1220 #if __cplusplus > 201402L
1221 reference
1222 #else
1223 void
1224 #endif
1225 emplace_back(_Args&&... __args)
1226 {
1227 this->_M_insert(end(), std::forward<_Args>(__args)...);
1228 #if __cplusplus > 201402L
1229 return back();
1230 #endif
1231 }
1232 #endif
1233
1234 /**
1235 * @brief Removes last element.
1236 *
1237 * This is a typical stack operation. It shrinks the %list by
1238 * one. Due to the nature of a %list this operation can be done
1239 * in constant time, and only invalidates iterators/references to
1240 * the element being removed.
1241 *
1242 * Note that no data is returned, and if the last element's data
1243 * is needed, it should be retrieved before pop_back() is called.
1244 */
1245 void
1246 pop_back() _GLIBCXX_NOEXCEPT
1247 { this->_M_erase(iterator(this->_M_impl._M_node._M_prev)); }
1248
1249 #if __cplusplus >= 201103L
1250 /**
1251 * @brief Constructs object in %list before specified iterator.
1252 * @param __position A const_iterator into the %list.
1253 * @param __args Arguments.
1254 * @return An iterator that points to the inserted data.
1255 *
1256 * This function will insert an object of type T constructed
1257 * with T(std::forward<Args>(args)...) before the specified
1258 * location. Due to the nature of a %list this operation can
1259 * be done in constant time, and does not invalidate iterators
1260 * and references.
1261 */
1262 template<typename... _Args>
1263 iterator
1264 emplace(const_iterator __position, _Args&&... __args);
1265
1266 /**
1267 * @brief Inserts given value into %list before specified iterator.
1268 * @param __position A const_iterator into the %list.
1269 * @param __x Data to be inserted.
1270 * @return An iterator that points to the inserted data.
1271 *
1272 * This function will insert a copy of the given value before
1273 * the specified location. Due to the nature of a %list this
1274 * operation can be done in constant time, and does not
1275 * invalidate iterators and references.
1276 */
1277 iterator
1278 insert(const_iterator __position, const value_type& __x);
1279 #else
1280 /**
1281 * @brief Inserts given value into %list before specified iterator.
1282 * @param __position An iterator into the %list.
1283 * @param __x Data to be inserted.
1284 * @return An iterator that points to the inserted data.
1285 *
1286 * This function will insert a copy of the given value before
1287 * the specified location. Due to the nature of a %list this
1288 * operation can be done in constant time, and does not
1289 * invalidate iterators and references.
1290 */
1291 iterator
1292 insert(iterator __position, const value_type& __x);
1293 #endif
1294
1295 #if __cplusplus >= 201103L
1296 /**
1297 * @brief Inserts given rvalue into %list before specified iterator.
1298 * @param __position A const_iterator into the %list.
1299 * @param __x Data to be inserted.
1300 * @return An iterator that points to the inserted data.
1301 *
1302 * This function will insert a copy of the given rvalue before
1303 * the specified location. Due to the nature of a %list this
1304 * operation can be done in constant time, and does not
1305 * invalidate iterators and references.
1306 */
1307 iterator
1308 insert(const_iterator __position, value_type&& __x)
1309 { return emplace(__position, std::move(__x)); }
1310
1311 /**
1312 * @brief Inserts the contents of an initializer_list into %list
1313 * before specified const_iterator.
1314 * @param __p A const_iterator into the %list.
1315 * @param __l An initializer_list of value_type.
1316 * @return An iterator pointing to the first element inserted
1317 * (or __position).
1318 *
1319 * This function will insert copies of the data in the
1320 * initializer_list @a l into the %list before the location
1321 * specified by @a p.
1322 *
1323 * This operation is linear in the number of elements inserted and
1324 * does not invalidate iterators and references.
1325 */
1326 iterator
1327 insert(const_iterator __p, initializer_list<value_type> __l)
1328 { return this->insert(__p, __l.begin(), __l.end()); }
1329 #endif
1330
1331 #if __cplusplus >= 201103L
1332 /**
1333 * @brief Inserts a number of copies of given data into the %list.
1334 * @param __position A const_iterator into the %list.
1335 * @param __n Number of elements to be inserted.
1336 * @param __x Data to be inserted.
1337 * @return An iterator pointing to the first element inserted
1338 * (or __position).
1339 *
1340 * This function will insert a specified number of copies of the
1341 * given data before the location specified by @a position.
1342 *
1343 * This operation is linear in the number of elements inserted and
1344 * does not invalidate iterators and references.
1345 */
1346 iterator
1347 insert(const_iterator __position, size_type __n, const value_type& __x);
1348 #else
1349 /**
1350 * @brief Inserts a number of copies of given data into the %list.
1351 * @param __position An iterator into the %list.
1352 * @param __n Number of elements to be inserted.
1353 * @param __x Data to be inserted.
1354 *
1355 * This function will insert a specified number of copies of the
1356 * given data before the location specified by @a position.
1357 *
1358 * This operation is linear in the number of elements inserted and
1359 * does not invalidate iterators and references.
1360 */
1361 void
1362 insert(iterator __position, size_type __n, const value_type& __x)
1363 {
1364 list __tmp(__n, __x, get_allocator());
1365 splice(__position, __tmp);
1366 }
1367 #endif
1368
1369 #if __cplusplus >= 201103L
1370 /**
1371 * @brief Inserts a range into the %list.
1372 * @param __position A const_iterator into the %list.
1373 * @param __first An input iterator.
1374 * @param __last An input iterator.
1375 * @return An iterator pointing to the first element inserted
1376 * (or __position).
1377 *
1378 * This function will insert copies of the data in the range [@a
1379 * first,@a last) into the %list before the location specified by
1380 * @a position.
1381 *
1382 * This operation is linear in the number of elements inserted and
1383 * does not invalidate iterators and references.
1384 */
1385 template<typename _InputIterator,
1386 typename = std::_RequireInputIter<_InputIterator>>
1387 iterator
1388 insert(const_iterator __position, _InputIterator __first,
1389 _InputIterator __last);
1390 #else
1391 /**
1392 * @brief Inserts a range into the %list.
1393 * @param __position An iterator into the %list.
1394 * @param __first An input iterator.
1395 * @param __last An input iterator.
1396 *
1397 * This function will insert copies of the data in the range [@a
1398 * first,@a last) into the %list before the location specified by
1399 * @a position.
1400 *
1401 * This operation is linear in the number of elements inserted and
1402 * does not invalidate iterators and references.
1403 */
1404 template<typename _InputIterator>
1405 void
1406 insert(iterator __position, _InputIterator __first,
1407 _InputIterator __last)
1408 {
1409 list __tmp(__first, __last, get_allocator());
1410 splice(__position, __tmp);
1411 }
1412 #endif
1413
1414 /**
1415 * @brief Remove element at given position.
1416 * @param __position Iterator pointing to element to be erased.
1417 * @return An iterator pointing to the next element (or end()).
1418 *
1419 * This function will erase the element at the given position and thus
1420 * shorten the %list by one.
1421 *
1422 * Due to the nature of a %list this operation can be done in
1423 * constant time, and only invalidates iterators/references to
1424 * the element being removed. The user is also cautioned that
1425 * this function only erases the element, and that if the element
1426 * is itself a pointer, the pointed-to memory is not touched in
1427 * any way. Managing the pointer is the user's responsibility.
1428 */
1429 iterator
1430 #if __cplusplus >= 201103L
1431 erase(const_iterator __position) noexcept;
1432 #else
1433 erase(iterator __position);
1434 #endif
1435
1436 /**
1437 * @brief Remove a range of elements.
1438 * @param __first Iterator pointing to the first element to be erased.
1439 * @param __last Iterator pointing to one past the last element to be
1440 * erased.
1441 * @return An iterator pointing to the element pointed to by @a last
1442 * prior to erasing (or end()).
1443 *
1444 * This function will erase the elements in the range @a
1445 * [first,last) and shorten the %list accordingly.
1446 *
1447 * This operation is linear time in the size of the range and only
1448 * invalidates iterators/references to the element being removed.
1449 * The user is also cautioned that this function only erases the
1450 * elements, and that if the elements themselves are pointers, the
1451 * pointed-to memory is not touched in any way. Managing the pointer
1452 * is the user's responsibility.
1453 */
1454 iterator
1455 #if __cplusplus >= 201103L
1456 erase(const_iterator __first, const_iterator __last) noexcept
1457 #else
1458 erase(iterator __first, iterator __last)
1459 #endif
1460 {
1461 while (__first != __last)
1462 __first = erase(__first);
1463 return __last._M_const_cast();
1464 }
1465
1466 /**
1467 * @brief Swaps data with another %list.
1468 * @param __x A %list of the same element and allocator types.
1469 *
1470 * This exchanges the elements between two lists in constant
1471 * time. Note that the global std::swap() function is
1472 * specialized such that std::swap(l1,l2) will feed to this
1473 * function.
1474 *
1475 * Whether the allocators are swapped depends on the allocator traits.
1476 */
1477 void
1478 swap(list& __x) _GLIBCXX_NOEXCEPT
1479 {
1480 __detail::_List_node_base::swap(this->_M_impl._M_node,
1481 __x._M_impl._M_node);
1482
1483 size_t __xsize = __x._M_get_size();
1484 __x._M_set_size(this->_M_get_size());
1485 this->_M_set_size(__xsize);
1486
1487 _Node_alloc_traits::_S_on_swap(this->_M_get_Node_allocator(),
1488 __x._M_get_Node_allocator());
1489 }
1490
1491 /**
1492 * Erases all the elements. Note that this function only erases
1493 * the elements, and that if the elements themselves are
1494 * pointers, the pointed-to memory is not touched in any way.
1495 * Managing the pointer is the user's responsibility.
1496 */
1497 void
1498 clear() _GLIBCXX_NOEXCEPT
1499 {
1500 _Base::_M_clear();
1501 _Base::_M_init();
1502 }
1503
1504 // [23.2.2.4] list operations
1505 /**
1506 * @brief Insert contents of another %list.
1507 * @param __position Iterator referencing the element to insert before.
1508 * @param __x Source list.
1509 *
1510 * The elements of @a __x are inserted in constant time in front of
1511 * the element referenced by @a __position. @a __x becomes an empty
1512 * list.
1513 *
1514 * Requires this != @a __x.
1515 */
1516 void
1517 #if __cplusplus >= 201103L
1518 splice(const_iterator __position, list&& __x) noexcept
1519 #else
1520 splice(iterator __position, list& __x)
1521 #endif
1522 {
1523 if (!__x.empty())
1524 {
1525 _M_check_equal_allocators(__x);
1526
1527 this->_M_transfer(__position._M_const_cast(),
1528 __x.begin(), __x.end());
1529
1530 this->_M_inc_size(__x._M_get_size());
1531 __x._M_set_size(0);
1532 }
1533 }
1534
1535 #if __cplusplus >= 201103L
1536 void
1537 splice(const_iterator __position, list& __x) noexcept
1538 { splice(__position, std::move(__x)); }
1539 #endif
1540
1541 #if __cplusplus >= 201103L
1542 /**
1543 * @brief Insert element from another %list.
1544 * @param __position Const_iterator referencing the element to
1545 * insert before.
1546 * @param __x Source list.
1547 * @param __i Const_iterator referencing the element to move.
1548 *
1549 * Removes the element in list @a __x referenced by @a __i and
1550 * inserts it into the current list before @a __position.
1551 */
1552 void
1553 splice(const_iterator __position, list&& __x, const_iterator __i) noexcept
1554 #else
1555 /**
1556 * @brief Insert element from another %list.
1557 * @param __position Iterator referencing the element to insert before.
1558 * @param __x Source list.
1559 * @param __i Iterator referencing the element to move.
1560 *
1561 * Removes the element in list @a __x referenced by @a __i and
1562 * inserts it into the current list before @a __position.
1563 */
1564 void
1565 splice(iterator __position, list& __x, iterator __i)
1566 #endif
1567 {
1568 iterator __j = __i._M_const_cast();
1569 ++__j;
1570 if (__position == __i || __position == __j)
1571 return;
1572
1573 if (this != std::__addressof(__x))
1574 _M_check_equal_allocators(__x);
1575
1576 this->_M_transfer(__position._M_const_cast(),
1577 __i._M_const_cast(), __j);
1578
1579 this->_M_inc_size(1);
1580 __x._M_dec_size(1);
1581 }
1582
1583 #if __cplusplus >= 201103L
1584 /**
1585 * @brief Insert element from another %list.
1586 * @param __position Const_iterator referencing the element to
1587 * insert before.
1588 * @param __x Source list.
1589 * @param __i Const_iterator referencing the element to move.
1590 *
1591 * Removes the element in list @a __x referenced by @a __i and
1592 * inserts it into the current list before @a __position.
1593 */
1594 void
1595 splice(const_iterator __position, list& __x, const_iterator __i) noexcept
1596 { splice(__position, std::move(__x), __i); }
1597 #endif
1598
1599 #if __cplusplus >= 201103L
1600 /**
1601 * @brief Insert range from another %list.
1602 * @param __position Const_iterator referencing the element to
1603 * insert before.
1604 * @param __x Source list.
1605 * @param __first Const_iterator referencing the start of range in x.
1606 * @param __last Const_iterator referencing the end of range in x.
1607 *
1608 * Removes elements in the range [__first,__last) and inserts them
1609 * before @a __position in constant time.
1610 *
1611 * Undefined if @a __position is in [__first,__last).
1612 */
1613 void
1614 splice(const_iterator __position, list&& __x, const_iterator __first,
1615 const_iterator __last) noexcept
1616 #else
1617 /**
1618 * @brief Insert range from another %list.
1619 * @param __position Iterator referencing the element to insert before.
1620 * @param __x Source list.
1621 * @param __first Iterator referencing the start of range in x.
1622 * @param __last Iterator referencing the end of range in x.
1623 *
1624 * Removes elements in the range [__first,__last) and inserts them
1625 * before @a __position in constant time.
1626 *
1627 * Undefined if @a __position is in [__first,__last).
1628 */
1629 void
1630 splice(iterator __position, list& __x, iterator __first,
1631 iterator __last)
1632 #endif
1633 {
1634 if (__first != __last)
1635 {
1636 if (this != std::__addressof(__x))
1637 _M_check_equal_allocators(__x);
1638
1639 size_t __n = _S_distance(__first, __last);
1640 this->_M_inc_size(__n);
1641 __x._M_dec_size(__n);
1642
1643 this->_M_transfer(__position._M_const_cast(),
1644 __first._M_const_cast(),
1645 __last._M_const_cast());
1646 }
1647 }
1648
1649 #if __cplusplus >= 201103L
1650 /**
1651 * @brief Insert range from another %list.
1652 * @param __position Const_iterator referencing the element to
1653 * insert before.
1654 * @param __x Source list.
1655 * @param __first Const_iterator referencing the start of range in x.
1656 * @param __last Const_iterator referencing the end of range in x.
1657 *
1658 * Removes elements in the range [__first,__last) and inserts them
1659 * before @a __position in constant time.
1660 *
1661 * Undefined if @a __position is in [__first,__last).
1662 */
1663 void
1664 splice(const_iterator __position, list& __x, const_iterator __first,
1665 const_iterator __last) noexcept
1666 { splice(__position, std::move(__x), __first, __last); }
1667 #endif
1668
1669 private:
1670 #if __cplusplus > 201703L
1671 # define __cpp_lib_list_remove_return_type 201806L
1672 typedef size_type __remove_return_type;
1673 # define _GLIBCXX_LIST_REMOVE_RETURN_TYPE_TAG \
1674 __attribute__((__abi_tag__("__cxx20")))
1675 #else
1676 typedef void __remove_return_type;
1677 # define _GLIBCXX_LIST_REMOVE_RETURN_TYPE_TAG
1678 #endif
1679 public:
1680
1681 /**
1682 * @brief Remove all elements equal to value.
1683 * @param __value The value to remove.
1684 *
1685 * Removes every element in the list equal to @a value.
1686 * Remaining elements stay in list order. Note that this
1687 * function only erases the elements, and that if the elements
1688 * themselves are pointers, the pointed-to memory is not
1689 * touched in any way. Managing the pointer is the user's
1690 * responsibility.
1691 */
1692 _GLIBCXX_LIST_REMOVE_RETURN_TYPE_TAG
1693 __remove_return_type
1694 remove(const _Tp& __value);
1695
1696 /**
1697 * @brief Remove all elements satisfying a predicate.
1698 * @tparam _Predicate Unary predicate function or object.
1699 *
1700 * Removes every element in the list for which the predicate
1701 * returns true. Remaining elements stay in list order. Note
1702 * that this function only erases the elements, and that if the
1703 * elements themselves are pointers, the pointed-to memory is
1704 * not touched in any way. Managing the pointer is the user's
1705 * responsibility.
1706 */
1707 template<typename _Predicate>
1708 __remove_return_type
1709 remove_if(_Predicate);
1710
1711 /**
1712 * @brief Remove consecutive duplicate elements.
1713 *
1714 * For each consecutive set of elements with the same value,
1715 * remove all but the first one. Remaining elements stay in
1716 * list order. Note that this function only erases the
1717 * elements, and that if the elements themselves are pointers,
1718 * the pointed-to memory is not touched in any way. Managing
1719 * the pointer is the user's responsibility.
1720 */
1721 _GLIBCXX_LIST_REMOVE_RETURN_TYPE_TAG
1722 __remove_return_type
1723 unique();
1724
1725 /**
1726 * @brief Remove consecutive elements satisfying a predicate.
1727 * @tparam _BinaryPredicate Binary predicate function or object.
1728 *
1729 * For each consecutive set of elements [first,last) that
1730 * satisfy predicate(first,i) where i is an iterator in
1731 * [first,last), remove all but the first one. Remaining
1732 * elements stay in list order. Note that this function only
1733 * erases the elements, and that if the elements themselves are
1734 * pointers, the pointed-to memory is not touched in any way.
1735 * Managing the pointer is the user's responsibility.
1736 */
1737 template<typename _BinaryPredicate>
1738 __remove_return_type
1739 unique(_BinaryPredicate);
1740
1741 #undef _GLIBCXX_LIST_REMOVE_RETURN_TYPE_TAG
1742
1743 /**
1744 * @brief Merge sorted lists.
1745 * @param __x Sorted list to merge.
1746 *
1747 * Assumes that both @a __x and this list are sorted according to
1748 * operator<(). Merges elements of @a __x into this list in
1749 * sorted order, leaving @a __x empty when complete. Elements in
1750 * this list precede elements in @a __x that are equal.
1751 */
1752 #if __cplusplus >= 201103L
1753 void
1754 merge(list&& __x);
1755
1756 void
1757 merge(list& __x)
1758 { merge(std::move(__x)); }
1759 #else
1760 void
1761 merge(list& __x);
1762 #endif
1763
1764 /**
1765 * @brief Merge sorted lists according to comparison function.
1766 * @tparam _StrictWeakOrdering Comparison function defining
1767 * sort order.
1768 * @param __x Sorted list to merge.
1769 * @param __comp Comparison functor.
1770 *
1771 * Assumes that both @a __x and this list are sorted according to
1772 * StrictWeakOrdering. Merges elements of @a __x into this list
1773 * in sorted order, leaving @a __x empty when complete. Elements
1774 * in this list precede elements in @a __x that are equivalent
1775 * according to StrictWeakOrdering().
1776 */
1777 #if __cplusplus >= 201103L
1778 template<typename _StrictWeakOrdering>
1779 void
1780 merge(list&& __x, _StrictWeakOrdering __comp);
1781
1782 template<typename _StrictWeakOrdering>
1783 void
1784 merge(list& __x, _StrictWeakOrdering __comp)
1785 { merge(std::move(__x), __comp); }
1786 #else
1787 template<typename _StrictWeakOrdering>
1788 void
1789 merge(list& __x, _StrictWeakOrdering __comp);
1790 #endif
1791
1792 /**
1793 * @brief Reverse the elements in list.
1794 *
1795 * Reverse the order of elements in the list in linear time.
1796 */
1797 void
1798 reverse() _GLIBCXX_NOEXCEPT
1799 { this->_M_impl._M_node._M_reverse(); }
1800
1801 /**
1802 * @brief Sort the elements.
1803 *
1804 * Sorts the elements of this list in NlogN time. Equivalent
1805 * elements remain in list order.
1806 */
1807 void
1808 sort();
1809
1810 /**
1811 * @brief Sort the elements according to comparison function.
1812 *
1813 * Sorts the elements of this list in NlogN time. Equivalent
1814 * elements remain in list order.
1815 */
1816 template<typename _StrictWeakOrdering>
1817 void
1818 sort(_StrictWeakOrdering);
1819
1820 protected:
1821 // Internal constructor functions follow.
1822
1823 // Called by the range constructor to implement [23.1.1]/9
1824
1825 // _GLIBCXX_RESOLVE_LIB_DEFECTS
1826 // 438. Ambiguity in the "do the right thing" clause
1827 template<typename _Integer>
1828 void
1829 _M_initialize_dispatch(_Integer __n, _Integer __x, __true_type)
1830 { _M_fill_initialize(static_cast<size_type>(__n), __x); }
1831
1832 // Called by the range constructor to implement [23.1.1]/9
1833 template<typename _InputIterator>
1834 void
1835 _M_initialize_dispatch(_InputIterator __first, _InputIterator __last,
1836 __false_type)
1837 {
1838 for (; __first != __last; ++__first)
1839 #if __cplusplus >= 201103L
1840 emplace_back(*__first);
1841 #else
1842 push_back(*__first);
1843 #endif
1844 }
1845
1846 // Called by list(n,v,a), and the range constructor when it turns out
1847 // to be the same thing.
1848 void
1849 _M_fill_initialize(size_type __n, const value_type& __x)
1850 {
1851 for (; __n; --__n)
1852 push_back(__x);
1853 }
1854
1855 #if __cplusplus >= 201103L
1856 // Called by list(n).
1857 void
1858 _M_default_initialize(size_type __n)
1859 {
1860 for (; __n; --__n)
1861 emplace_back();
1862 }
1863
1864 // Called by resize(sz).
1865 void
1866 _M_default_append(size_type __n);
1867 #endif
1868
1869 // Internal assign functions follow.
1870
1871 // Called by the range assign to implement [23.1.1]/9
1872
1873 // _GLIBCXX_RESOLVE_LIB_DEFECTS
1874 // 438. Ambiguity in the "do the right thing" clause
1875 template<typename _Integer>
1876 void
1877 _M_assign_dispatch(_Integer __n, _Integer __val, __true_type)
1878 { _M_fill_assign(__n, __val); }
1879
1880 // Called by the range assign to implement [23.1.1]/9
1881 template<typename _InputIterator>
1882 void
1883 _M_assign_dispatch(_InputIterator __first, _InputIterator __last,
1884 __false_type);
1885
1886 // Called by assign(n,t), and the range assign when it turns out
1887 // to be the same thing.
1888 void
1889 _M_fill_assign(size_type __n, const value_type& __val);
1890
1891
1892 // Moves the elements from [first,last) before position.
1893 void
1894 _M_transfer(iterator __position, iterator __first, iterator __last)
1895 { __position._M_node->_M_transfer(__first._M_node, __last._M_node); }
1896
1897 // Inserts new element at position given and with value given.
1898 #if __cplusplus < 201103L
1899 void
1900 _M_insert(iterator __position, const value_type& __x)
1901 {
1902 _Node* __tmp = _M_create_node(__x);
1903 __tmp->_M_hook(__position._M_node);
1904 this->_M_inc_size(1);
1905 }
1906 #else
1907 template<typename... _Args>
1908 void
1909 _M_insert(iterator __position, _Args&&... __args)
1910 {
1911 _Node* __tmp = _M_create_node(std::forward<_Args>(__args)...);
1912 __tmp->_M_hook(__position._M_node);
1913 this->_M_inc_size(1);
1914 }
1915 #endif
1916
1917 // Erases element at position given.
1918 void
1919 _M_erase(iterator __position) _GLIBCXX_NOEXCEPT
1920 {
1921 this->_M_dec_size(1);
1922 __position._M_node->_M_unhook();
1923 _Node* __n = static_cast<_Node*>(__position._M_node);
1924 #if __cplusplus >= 201103L
1925 _Node_alloc_traits::destroy(_M_get_Node_allocator(), __n->_M_valptr());
1926 #else
1927 _Tp_alloc_type(_M_get_Node_allocator()).destroy(__n->_M_valptr());
1928 #endif
1929
1930 _M_put_node(__n);
1931 }
1932
1933 // To implement the splice (and merge) bits of N1599.
1934 void
1935 _M_check_equal_allocators(list& __x) _GLIBCXX_NOEXCEPT
1936 {
1937 if (std::__alloc_neq<typename _Base::_Node_alloc_type>::
1938 _S_do_it(_M_get_Node_allocator(), __x._M_get_Node_allocator()))
1939 __builtin_abort();
1940 }
1941
1942 // Used to implement resize.
1943 const_iterator
1944 _M_resize_pos(size_type& __new_size) const;
1945
1946 #if __cplusplus >= 201103L
1947 void
1948 _M_move_assign(list&& __x, true_type) noexcept
1949 {
1950 this->_M_clear();
1951 this->_M_move_nodes(std::move(__x));
1952 std::__alloc_on_move(this->_M_get_Node_allocator(),
1953 __x._M_get_Node_allocator());
1954 }
1955
1956 void
1957 _M_move_assign(list&& __x, false_type)
1958 {
1959 if (__x._M_get_Node_allocator() == this->_M_get_Node_allocator())
1960 _M_move_assign(std::move(__x), true_type{});
1961 else
1962 // The rvalue's allocator cannot be moved, or is not equal,
1963 // so we need to individually move each element.
1964 _M_assign_dispatch(std::make_move_iterator(__x.begin()),
1965 std::make_move_iterator(__x.end()),
1966 __false_type{});
1967 }
1968 #endif
1969 };
1970
1971 #if __cpp_deduction_guides >= 201606
1972 template<typename _InputIterator, typename _ValT
1973 = typename iterator_traits<_InputIterator>::value_type,
1974 typename _Allocator = allocator<_ValT>,
1975 typename = _RequireInputIter<_InputIterator>,
1976 typename = _RequireAllocator<_Allocator>>
1977 list(_InputIterator, _InputIterator, _Allocator = _Allocator())
1978 -> list<_ValT, _Allocator>;
1979 #endif
1980
1981 _GLIBCXX_END_NAMESPACE_CXX11
1982
1983 /**
1984 * @brief List equality comparison.
1985 * @param __x A %list.
1986 * @param __y A %list of the same type as @a __x.
1987 * @return True iff the size and elements of the lists are equal.
1988 *
1989 * This is an equivalence relation. It is linear in the size of
1990 * the lists. Lists are considered equivalent if their sizes are
1991 * equal, and if corresponding elements compare equal.
1992 */
1993 template<typename _Tp, typename _Alloc>
1994 inline bool
1995 operator==(const list<_Tp, _Alloc>& __x, const list<_Tp, _Alloc>& __y)
1996 {
1997 #if _GLIBCXX_USE_CXX11_ABI
1998 if (__x.size() != __y.size())
1999 return false;
2000 #endif
2001
2002 typedef typename list<_Tp, _Alloc>::const_iterator const_iterator;
2003 const_iterator __end1 = __x.end();
2004 const_iterator __end2 = __y.end();
2005
2006 const_iterator __i1 = __x.begin();
2007 const_iterator __i2 = __y.begin();
2008 while (__i1 != __end1 && __i2 != __end2 && *__i1 == *__i2)
2009 {
2010 ++__i1;
2011 ++__i2;
2012 }
2013 return __i1 == __end1 && __i2 == __end2;
2014 }
2015
2016 #if __cpp_lib_three_way_comparison
2017 /**
2018 * @brief List ordering relation.
2019 * @param __x A `list`.
2020 * @param __y A `list` of the same type as `__x`.
2021 * @return A value indicating whether `__x` is less than, equal to,
2022 * greater than, or incomparable with `__y`.
2023 *
2024 * See `std::lexicographical_compare_three_way()` for how the determination
2025 * is made. This operator is used to synthesize relational operators like
2026 * `<` and `>=` etc.
2027 */
2028 template<typename _Tp, typename _Alloc>
2029 inline __detail::__synth3way_t<_Tp>
2030 operator<=>(const list<_Tp, _Alloc>& __x, const list<_Tp, _Alloc>& __y)
2031 {
2032 return std::lexicographical_compare_three_way(__x.begin(), __x.end(),
2033 __y.begin(), __y.end(),
2034 __detail::__synth3way);
2035 }
2036 #else
2037 /**
2038 * @brief List ordering relation.
2039 * @param __x A %list.
2040 * @param __y A %list of the same type as @a __x.
2041 * @return True iff @a __x is lexicographically less than @a __y.
2042 *
2043 * This is a total ordering relation. It is linear in the size of the
2044 * lists. The elements must be comparable with @c <.
2045 *
2046 * See std::lexicographical_compare() for how the determination is made.
2047 */
2048 template<typename _Tp, typename _Alloc>
2049 inline bool
2050 operator<(const list<_Tp, _Alloc>& __x, const list<_Tp, _Alloc>& __y)
2051 { return std::lexicographical_compare(__x.begin(), __x.end(),
2052 __y.begin(), __y.end()); }
2053
2054 /// Based on operator==
2055 template<typename _Tp, typename _Alloc>
2056 inline bool
2057 operator!=(const list<_Tp, _Alloc>& __x, const list<_Tp, _Alloc>& __y)
2058 { return !(__x == __y); }
2059
2060 /// Based on operator<
2061 template<typename _Tp, typename _Alloc>
2062 inline bool
2063 operator>(const list<_Tp, _Alloc>& __x, const list<_Tp, _Alloc>& __y)
2064 { return __y < __x; }
2065
2066 /// Based on operator<
2067 template<typename _Tp, typename _Alloc>
2068 inline bool
2069 operator<=(const list<_Tp, _Alloc>& __x, const list<_Tp, _Alloc>& __y)
2070 { return !(__y < __x); }
2071
2072 /// Based on operator<
2073 template<typename _Tp, typename _Alloc>
2074 inline bool
2075 operator>=(const list<_Tp, _Alloc>& __x, const list<_Tp, _Alloc>& __y)
2076 { return !(__x < __y); }
2077 #endif // three-way comparison
2078
2079 /// See std::list::swap().
2080 template<typename _Tp, typename _Alloc>
2081 inline void
2082 swap(list<_Tp, _Alloc>& __x, list<_Tp, _Alloc>& __y)
2083 _GLIBCXX_NOEXCEPT_IF(noexcept(__x.swap(__y)))
2084 { __x.swap(__y); }
2085
2086 _GLIBCXX_END_NAMESPACE_CONTAINER
2087
2088 #if _GLIBCXX_USE_CXX11_ABI
2089
2090 // Detect when distance is used to compute the size of the whole list.
2091 template<typename _Tp>
2092 inline ptrdiff_t
2093 __distance(_GLIBCXX_STD_C::_List_iterator<_Tp> __first,
2094 _GLIBCXX_STD_C::_List_iterator<_Tp> __last,
2095 input_iterator_tag __tag)
2096 {
2097 typedef _GLIBCXX_STD_C::_List_const_iterator<_Tp> _CIter;
2098 return std::__distance(_CIter(__first), _CIter(__last), __tag);
2099 }
2100
2101 template<typename _Tp>
2102 inline ptrdiff_t
2103 __distance(_GLIBCXX_STD_C::_List_const_iterator<_Tp> __first,
2104 _GLIBCXX_STD_C::_List_const_iterator<_Tp> __last,
2105 input_iterator_tag)
2106 {
2107 typedef __detail::_List_node_header _Sentinel;
2108 _GLIBCXX_STD_C::_List_const_iterator<_Tp> __beyond = __last;
2109 ++__beyond;
2110 const bool __whole = __first == __beyond;
2111 if (__builtin_constant_p (__whole) && __whole)
2112 return static_cast<const _Sentinel*>(__last._M_node)->_M_size;
2113
2114 ptrdiff_t __n = 0;
2115 while (__first != __last)
2116 {
2117 ++__first;
2118 ++__n;
2119 }
2120 return __n;
2121 }
2122 #endif
2123
2124 _GLIBCXX_END_NAMESPACE_VERSION
2125 } // namespace std
2126
2127 #endif /* _STL_LIST_H */
2128