1// Multiset implementation -*- C++ -*-
2
3// Copyright (C) 2001-2022 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
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_multiset.h
52 * This is an internal header file, included by other library headers.
53 * Do not attempt to use it directly. @headername{set}
54 */
55
56#ifndef _STL_MULTISET_H
57#define _STL_MULTISET_H 1
58
59#include <bits/concept_check.h>
60#if __cplusplus >= 201103L
61#include <initializer_list>
62#endif
63
64namespace std _GLIBCXX_VISIBILITY(default)
65{
66_GLIBCXX_BEGIN_NAMESPACE_VERSION
67_GLIBCXX_BEGIN_NAMESPACE_CONTAINER
68
69 template<typename _Key, typename _Compare, typename _Alloc>
70 class set;
71
72 /**
73 * @brief A standard container made up of elements, which can be retrieved
74 * in logarithmic time.
75 *
76 * @ingroup associative_containers
77 *
78 *
79 * @tparam _Key Type of key objects.
80 * @tparam _Compare Comparison function object type, defaults to less<_Key>.
81 * @tparam _Alloc Allocator type, defaults to allocator<_Key>.
82 *
83 * Meets the requirements of a <a href="tables.html#65">container</a>, a
84 * <a href="tables.html#66">reversible container</a>, and an
85 * <a href="tables.html#69">associative container</a> (using equivalent
86 * keys). For a @c multiset<Key> the key_type and value_type are Key.
87 *
88 * Multisets support bidirectional iterators.
89 *
90 * The private tree data is declared exactly the same way for set and
91 * multiset; the distinction is made entirely in how the tree functions are
92 * called (*_unique versus *_equal, same as the standard).
93 */
94 template <typename _Key, typename _Compare = std::less<_Key>,
95 typename _Alloc = std::allocator<_Key> >
96 class multiset
97 {
98#ifdef _GLIBCXX_CONCEPT_CHECKS
99 // concept requirements
100 typedef typename _Alloc::value_type _Alloc_value_type;
101# if __cplusplus < 201103L
102 __glibcxx_class_requires(_Key, _SGIAssignableConcept)
103# endif
104 __glibcxx_class_requires4(_Compare, bool, _Key, _Key,
105 _BinaryFunctionConcept)
106 __glibcxx_class_requires2(_Key, _Alloc_value_type, _SameTypeConcept)
107#endif
108
109#if __cplusplus >= 201103L
110 static_assert(is_same<typename remove_cv<_Key>::type, _Key>::value,
111 "std::multiset must have a non-const, non-volatile value_type");
112# if __cplusplus > 201703L || defined __STRICT_ANSI__
113 static_assert(is_same<typename _Alloc::value_type, _Key>::value,
114 "std::multiset must have the same value_type as its allocator");
115# endif
116#endif
117
118 public:
119 // typedefs:
120 typedef _Key key_type;
121 typedef _Key value_type;
122 typedef _Compare key_compare;
123 typedef _Compare value_compare;
124 typedef _Alloc allocator_type;
125
126 private:
127 /// This turns a red-black tree into a [multi]set.
128 typedef typename __gnu_cxx::__alloc_traits<_Alloc>::template
129 rebind<_Key>::other _Key_alloc_type;
130
131 typedef _Rb_tree<key_type, value_type, _Identity<value_type>,
132 key_compare, _Key_alloc_type> _Rep_type;
133 /// The actual tree structure.
134 _Rep_type _M_t;
135
136 typedef __gnu_cxx::__alloc_traits<_Key_alloc_type> _Alloc_traits;
137
138 public:
139 typedef typename _Alloc_traits::pointer pointer;
140 typedef typename _Alloc_traits::const_pointer const_pointer;
141 typedef typename _Alloc_traits::reference reference;
142 typedef typename _Alloc_traits::const_reference const_reference;
143 // _GLIBCXX_RESOLVE_LIB_DEFECTS
144 // DR 103. set::iterator is required to be modifiable,
145 // but this allows modification of keys.
146 typedef typename _Rep_type::const_iterator iterator;
147 typedef typename _Rep_type::const_iterator const_iterator;
148 typedef typename _Rep_type::const_reverse_iterator reverse_iterator;
149 typedef typename _Rep_type::const_reverse_iterator const_reverse_iterator;
150 typedef typename _Rep_type::size_type size_type;
151 typedef typename _Rep_type::difference_type difference_type;
152
153#if __cplusplus > 201402L
154 using node_type = typename _Rep_type::node_type;
155#endif
156
157 // allocation/deallocation
158 /**
159 * @brief Default constructor creates no elements.
160 */
161#if __cplusplus < 201103L
162 multiset() : _M_t() { }
163#else
164 multiset() = default;
165#endif
166
167 /**
168 * @brief Creates a %multiset with no elements.
169 * @param __comp Comparator to use.
170 * @param __a An allocator object.
171 */
172 explicit
173 multiset(const _Compare& __comp,
174 const allocator_type& __a = allocator_type())
175 : _M_t(__comp, _Key_alloc_type(__a)) { }
176
177 /**
178 * @brief Builds a %multiset from a range.
179 * @param __first An input iterator.
180 * @param __last An input iterator.
181 *
182 * Create a %multiset consisting of copies of the elements from
183 * [first,last). This is linear in N if the range is already sorted,
184 * and NlogN otherwise (where N is distance(__first,__last)).
185 */
186 template<typename _InputIterator>
187 multiset(_InputIterator __first, _InputIterator __last)
188 : _M_t()
189 { _M_t._M_insert_range_equal(__first, __last); }
190
191 /**
192 * @brief Builds a %multiset from a range.
193 * @param __first An input iterator.
194 * @param __last An input iterator.
195 * @param __comp A comparison functor.
196 * @param __a An allocator object.
197 *
198 * Create a %multiset consisting of copies of the elements from
199 * [__first,__last). This is linear in N if the range is already sorted,
200 * and NlogN otherwise (where N is distance(__first,__last)).
201 */
202 template<typename _InputIterator>
203 multiset(_InputIterator __first, _InputIterator __last,
204 const _Compare& __comp,
205 const allocator_type& __a = allocator_type())
206 : _M_t(__comp, _Key_alloc_type(__a))
207 { _M_t._M_insert_range_equal(__first, __last); }
208
209 /**
210 * @brief %Multiset copy constructor.
211 *
212 * Whether the allocator is copied depends on the allocator traits.
213 */
214#if __cplusplus < 201103L
215 multiset(const multiset& __x)
216 : _M_t(__x._M_t) { }
217#else
218 multiset(const multiset&) = default;
219
220 /**
221 * @brief %Multiset move constructor.
222 *
223 * The newly-created %multiset contains the exact contents of the
224 * moved instance. The moved instance is a valid, but unspecified
225 * %multiset.
226 */
227 multiset(multiset&&) = default;
228
229 /**
230 * @brief Builds a %multiset from an initializer_list.
231 * @param __l An initializer_list.
232 * @param __comp A comparison functor.
233 * @param __a An allocator object.
234 *
235 * Create a %multiset consisting of copies of the elements from
236 * the list. This is linear in N if the list is already sorted,
237 * and NlogN otherwise (where N is @a __l.size()).
238 */
239 multiset(initializer_list<value_type> __l,
240 const _Compare& __comp = _Compare(),
241 const allocator_type& __a = allocator_type())
242 : _M_t(__comp, _Key_alloc_type(__a))
243 { _M_t._M_insert_range_equal(__l.begin(), __l.end()); }
244
245 /// Allocator-extended default constructor.
246 explicit
247 multiset(const allocator_type& __a)
248 : _M_t(_Key_alloc_type(__a)) { }
249
250 /// Allocator-extended copy constructor.
251 multiset(const multiset& __m,
252 const __type_identity_t<allocator_type>& __a)
253 : _M_t(__m._M_t, _Key_alloc_type(__a)) { }
254
255 /// Allocator-extended move constructor.
256 multiset(multiset&& __m, const __type_identity_t<allocator_type>& __a)
257 noexcept(is_nothrow_copy_constructible<_Compare>::value
258 && _Alloc_traits::_S_always_equal())
259 : _M_t(std::move(__m._M_t), _Key_alloc_type(__a)) { }
260
261 /// Allocator-extended initialier-list constructor.
262 multiset(initializer_list<value_type> __l, const allocator_type& __a)
263 : _M_t(_Key_alloc_type(__a))
264 { _M_t._M_insert_range_equal(__l.begin(), __l.end()); }
265
266 /// Allocator-extended range constructor.
267 template<typename _InputIterator>
268 multiset(_InputIterator __first, _InputIterator __last,
269 const allocator_type& __a)
270 : _M_t(_Key_alloc_type(__a))
271 { _M_t._M_insert_range_equal(__first, __last); }
272
273 /**
274 * The dtor only erases the elements, and note that if the elements
275 * themselves are pointers, the pointed-to memory is not touched in any
276 * way. Managing the pointer is the user's responsibility.
277 */
278 ~multiset() = default;
279#endif
280
281 /**
282 * @brief %Multiset assignment operator.
283 *
284 * Whether the allocator is copied depends on the allocator traits.
285 */
286#if __cplusplus < 201103L
287 multiset&
288 operator=(const multiset& __x)
289 {
290 _M_t = __x._M_t;
291 return *this;
292 }
293#else
294 multiset&
295 operator=(const multiset&) = default;
296
297 /// Move assignment operator.
298 multiset&
299 operator=(multiset&&) = default;
300
301 /**
302 * @brief %Multiset list assignment operator.
303 * @param __l An initializer_list.
304 *
305 * This function fills a %multiset with copies of the elements in the
306 * initializer list @a __l.
307 *
308 * Note that the assignment completely changes the %multiset and
309 * that the resulting %multiset's size is the same as the number
310 * of elements assigned.
311 */
312 multiset&
313 operator=(initializer_list<value_type> __l)
314 {
315 _M_t._M_assign_equal(__l.begin(), __l.end());
316 return *this;
317 }
318#endif
319
320 // accessors:
321
322 /// Returns the comparison object.
323 key_compare
324 key_comp() const
325 { return _M_t.key_comp(); }
326 /// Returns the comparison object.
327 value_compare
328 value_comp() const
329 { return _M_t.key_comp(); }
330 /// Returns the memory allocation object.
331 allocator_type
332 get_allocator() const _GLIBCXX_NOEXCEPT
333 { return allocator_type(_M_t.get_allocator()); }
334
335 /**
336 * Returns a read-only (constant) iterator that points to the first
337 * element in the %multiset. Iteration is done in ascending order
338 * according to the keys.
339 */
340 iterator
341 begin() const _GLIBCXX_NOEXCEPT
342 { return _M_t.begin(); }
343
344 /**
345 * Returns a read-only (constant) iterator that points one past the last
346 * element in the %multiset. Iteration is done in ascending order
347 * according to the keys.
348 */
349 iterator
350 end() const _GLIBCXX_NOEXCEPT
351 { return _M_t.end(); }
352
353 /**
354 * Returns a read-only (constant) reverse iterator that points to the
355 * last element in the %multiset. Iteration is done in descending order
356 * according to the keys.
357 */
358 reverse_iterator
359 rbegin() const _GLIBCXX_NOEXCEPT
360 { return _M_t.rbegin(); }
361
362 /**
363 * Returns a read-only (constant) reverse iterator that points to the
364 * last element in the %multiset. Iteration is done in descending order
365 * according to the keys.
366 */
367 reverse_iterator
368 rend() const _GLIBCXX_NOEXCEPT
369 { return _M_t.rend(); }
370
371#if __cplusplus >= 201103L
372 /**
373 * Returns a read-only (constant) iterator that points to the first
374 * element in the %multiset. Iteration is done in ascending order
375 * according to the keys.
376 */
377 iterator
378 cbegin() const noexcept
379 { return _M_t.begin(); }
380
381 /**
382 * Returns a read-only (constant) iterator that points one past the last
383 * element in the %multiset. Iteration is done in ascending order
384 * according to the keys.
385 */
386 iterator
387 cend() const noexcept
388 { return _M_t.end(); }
389
390 /**
391 * Returns a read-only (constant) reverse iterator that points to the
392 * last element in the %multiset. Iteration is done in descending order
393 * according to the keys.
394 */
395 reverse_iterator
396 crbegin() const noexcept
397 { return _M_t.rbegin(); }
398
399 /**
400 * Returns a read-only (constant) reverse iterator that points to the
401 * last element in the %multiset. Iteration is done in descending order
402 * according to the keys.
403 */
404 reverse_iterator
405 crend() const noexcept
406 { return _M_t.rend(); }
407#endif
408
409 /// Returns true if the %set is empty.
410 _GLIBCXX_NODISCARD bool
411 empty() const _GLIBCXX_NOEXCEPT
412 { return _M_t.empty(); }
413
414 /// Returns the size of the %set.
415 size_type
416 size() const _GLIBCXX_NOEXCEPT
417 { return _M_t.size(); }
418
419 /// Returns the maximum size of the %set.
420 size_type
421 max_size() const _GLIBCXX_NOEXCEPT
422 { return _M_t.max_size(); }
423
424 /**
425 * @brief Swaps data with another %multiset.
426 * @param __x A %multiset of the same element and allocator types.
427 *
428 * This exchanges the elements between two multisets in constant time.
429 * (It is only swapping a pointer, an integer, and an instance of the @c
430 * Compare type (which itself is often stateless and empty), so it should
431 * be quite fast.)
432 * Note that the global std::swap() function is specialized such that
433 * std::swap(s1,s2) will feed to this function.
434 *
435 * Whether the allocators are swapped depends on the allocator traits.
436 */
437 void
438 swap(multiset& __x)
439 _GLIBCXX_NOEXCEPT_IF(__is_nothrow_swappable<_Compare>::value)
440 { _M_t.swap(__x._M_t); }
441
442 // insert/erase
443#if __cplusplus >= 201103L
444 /**
445 * @brief Builds and inserts an element into the %multiset.
446 * @param __args Arguments used to generate the element instance to be
447 * inserted.
448 * @return An iterator that points to the inserted element.
449 *
450 * This function inserts an element into the %multiset. Contrary
451 * to a std::set the %multiset does not rely on unique keys and thus
452 * multiple copies of the same element can be inserted.
453 *
454 * Insertion requires logarithmic time.
455 */
456 template<typename... _Args>
457 iterator
458 emplace(_Args&&... __args)
459 { return _M_t._M_emplace_equal(std::forward<_Args>(__args)...); }
460
461 /**
462 * @brief Builds and inserts an element into the %multiset.
463 * @param __pos An iterator that serves as a hint as to where the
464 * element should be inserted.
465 * @param __args Arguments used to generate the element instance to be
466 * inserted.
467 * @return An iterator that points to the inserted element.
468 *
469 * This function inserts an element into the %multiset. Contrary
470 * to a std::set the %multiset does not rely on unique keys and thus
471 * multiple copies of the same element can be inserted.
472 *
473 * Note that the first parameter is only a hint and can potentially
474 * improve the performance of the insertion process. A bad hint would
475 * cause no gains in efficiency.
476 *
477 * See https://gcc.gnu.org/onlinedocs/libstdc++/manual/associative.html#containers.associative.insert_hints
478 * for more on @a hinting.
479 *
480 * Insertion requires logarithmic time (if the hint is not taken).
481 */
482 template<typename... _Args>
483 iterator
484 emplace_hint(const_iterator __pos, _Args&&... __args)
485 {
486 return _M_t._M_emplace_hint_equal(__pos,
487 std::forward<_Args>(__args)...);
488 }
489#endif
490
491 /**
492 * @brief Inserts an element into the %multiset.
493 * @param __x Element to be inserted.
494 * @return An iterator that points to the inserted element.
495 *
496 * This function inserts an element into the %multiset. Contrary
497 * to a std::set the %multiset does not rely on unique keys and thus
498 * multiple copies of the same element can be inserted.
499 *
500 * Insertion requires logarithmic time.
501 */
502 iterator
503 insert(const value_type& __x)
504 { return _M_t._M_insert_equal(__x); }
505
506#if __cplusplus >= 201103L
507 iterator
508 insert(value_type&& __x)
509 { return _M_t._M_insert_equal(std::move(__x)); }
510#endif
511
512 /**
513 * @brief Inserts an element into the %multiset.
514 * @param __position An iterator that serves as a hint as to where the
515 * element should be inserted.
516 * @param __x Element to be inserted.
517 * @return An iterator that points to the inserted element.
518 *
519 * This function inserts an element into the %multiset. Contrary
520 * to a std::set the %multiset does not rely on unique keys and thus
521 * multiple copies of the same element can be inserted.
522 *
523 * Note that the first parameter is only a hint and can potentially
524 * improve the performance of the insertion process. A bad hint would
525 * cause no gains in efficiency.
526 *
527 * See https://gcc.gnu.org/onlinedocs/libstdc++/manual/associative.html#containers.associative.insert_hints
528 * for more on @a hinting.
529 *
530 * Insertion requires logarithmic time (if the hint is not taken).
531 */
532 iterator
533 insert(const_iterator __position, const value_type& __x)
534 { return _M_t._M_insert_equal_(__position, __x); }
535
536#if __cplusplus >= 201103L
537 iterator
538 insert(const_iterator __position, value_type&& __x)
539 { return _M_t._M_insert_equal_(__position, std::move(__x)); }
540#endif
541
542 /**
543 * @brief A template function that tries to insert a range of elements.
544 * @param __first Iterator pointing to the start of the range to be
545 * inserted.
546 * @param __last Iterator pointing to the end of the range.
547 *
548 * Complexity similar to that of the range constructor.
549 */
550 template<typename _InputIterator>
551 void
552 insert(_InputIterator __first, _InputIterator __last)
553 { _M_t._M_insert_range_equal(__first, __last); }
554
555#if __cplusplus >= 201103L
556 /**
557 * @brief Attempts to insert a list of elements into the %multiset.
558 * @param __l A std::initializer_list<value_type> of elements
559 * to be inserted.
560 *
561 * Complexity similar to that of the range constructor.
562 */
563 void
564 insert(initializer_list<value_type> __l)
565 { this->insert(__l.begin(), __l.end()); }
566#endif
567
568#if __cplusplus > 201402L
569 /// Extract a node.
570 node_type
571 extract(const_iterator __pos)
572 {
573 __glibcxx_assert(__pos != end());
574 return _M_t.extract(__pos);
575 }
576
577 /// Extract a node.
578 node_type
579 extract(const key_type& __x)
580 { return _M_t.extract(__x); }
581
582 /// Re-insert an extracted node.
583 iterator
584 insert(node_type&& __nh)
585 { return _M_t._M_reinsert_node_equal(std::move(__nh)); }
586
587 /// Re-insert an extracted node.
588 iterator
589 insert(const_iterator __hint, node_type&& __nh)
590 { return _M_t._M_reinsert_node_hint_equal(__hint, std::move(__nh)); }
591
592 template<typename, typename>
593 friend struct std::_Rb_tree_merge_helper;
594
595 template<typename _Compare1>
596 void
597 merge(multiset<_Key, _Compare1, _Alloc>& __source)
598 {
599 using _Merge_helper = _Rb_tree_merge_helper<multiset, _Compare1>;
600 _M_t._M_merge_equal(_Merge_helper::_S_get_tree(__source));
601 }
602
603 template<typename _Compare1>
604 void
605 merge(multiset<_Key, _Compare1, _Alloc>&& __source)
606 { merge(__source); }
607
608 template<typename _Compare1>
609 void
610 merge(set<_Key, _Compare1, _Alloc>& __source)
611 {
612 using _Merge_helper = _Rb_tree_merge_helper<multiset, _Compare1>;
613 _M_t._M_merge_equal(_Merge_helper::_S_get_tree(__source));
614 }
615
616 template<typename _Compare1>
617 void
618 merge(set<_Key, _Compare1, _Alloc>&& __source)
619 { merge(__source); }
620#endif // C++17
621
622#if __cplusplus >= 201103L
623 // _GLIBCXX_RESOLVE_LIB_DEFECTS
624 // DR 130. Associative erase should return an iterator.
625 /**
626 * @brief Erases an element from a %multiset.
627 * @param __position An iterator pointing to the element to be erased.
628 * @return An iterator pointing to the element immediately following
629 * @a position prior to the element being erased. If no such
630 * element exists, end() is returned.
631 *
632 * This function erases an element, pointed to by the given iterator,
633 * from a %multiset. Note that this function only erases the element,
634 * and that if the element is itself a pointer, the pointed-to memory is
635 * not touched in any way. Managing the pointer is the user's
636 * responsibility.
637 */
638 _GLIBCXX_ABI_TAG_CXX11
639 iterator
640 erase(const_iterator __position)
641 { return _M_t.erase(__position); }
642#else
643 /**
644 * @brief Erases an element from a %multiset.
645 * @param __position An iterator pointing to the element to be erased.
646 *
647 * This function erases an element, pointed to by the given iterator,
648 * from a %multiset. Note that this function only erases the element,
649 * and that if the element is itself a pointer, the pointed-to memory is
650 * not touched in any way. Managing the pointer is the user's
651 * responsibility.
652 */
653 void
654 erase(iterator __position)
655 { _M_t.erase(__position); }
656#endif
657
658 /**
659 * @brief Erases elements according to the provided key.
660 * @param __x Key of element to be erased.
661 * @return The number of elements erased.
662 *
663 * This function erases all elements located by the given key from a
664 * %multiset.
665 * Note that this function only erases the element, and that if
666 * the element is itself a pointer, the pointed-to memory is not touched
667 * in any way. Managing the pointer is the user's responsibility.
668 */
669 size_type
670 erase(const key_type& __x)
671 { return _M_t.erase(__x); }
672
673#if __cplusplus >= 201103L
674 // _GLIBCXX_RESOLVE_LIB_DEFECTS
675 // DR 130. Associative erase should return an iterator.
676 /**
677 * @brief Erases a [first,last) range of elements from a %multiset.
678 * @param __first Iterator pointing to the start of the range to be
679 * erased.
680 * @param __last Iterator pointing to the end of the range to
681 * be erased.
682 * @return The iterator @a last.
683 *
684 * This function erases a sequence of elements from a %multiset.
685 * Note that this function only erases the elements, and that if
686 * the elements themselves are pointers, the pointed-to memory is not
687 * touched in any way. Managing the pointer is the user's
688 * responsibility.
689 */
690 _GLIBCXX_ABI_TAG_CXX11
691 iterator
692 erase(const_iterator __first, const_iterator __last)
693 { return _M_t.erase(__first, __last); }
694#else
695 /**
696 * @brief Erases a [first,last) range of elements from a %multiset.
697 * @param first Iterator pointing to the start of the range to be
698 * erased.
699 * @param last Iterator pointing to the end of the range to be erased.
700 *
701 * This function erases a sequence of elements from a %multiset.
702 * Note that this function only erases the elements, and that if
703 * the elements themselves are pointers, the pointed-to memory is not
704 * touched in any way. Managing the pointer is the user's
705 * responsibility.
706 */
707 void
708 erase(iterator __first, iterator __last)
709 { _M_t.erase(__first, __last); }
710#endif
711
712 /**
713 * Erases all elements in a %multiset. Note that this function only
714 * erases the elements, and that if the elements themselves are pointers,
715 * the pointed-to memory is not touched in any way. Managing the pointer
716 * is the user's responsibility.
717 */
718 void
719 clear() _GLIBCXX_NOEXCEPT
720 { _M_t.clear(); }
721
722 // multiset operations:
723
724 ///@{
725 /**
726 * @brief Finds the number of elements with given key.
727 * @param __x Key of elements to be located.
728 * @return Number of elements with specified key.
729 */
730 size_type
731 count(const key_type& __x) const
732 { return _M_t.count(__x); }
733
734#if __cplusplus > 201103L
735 template<typename _Kt>
736 auto
737 count(const _Kt& __x) const -> decltype(_M_t._M_count_tr(__x))
738 { return _M_t._M_count_tr(__x); }
739#endif
740 ///@}
741
742#if __cplusplus > 201703L
743 ///@{
744 /**
745 * @brief Finds whether an element with the given key exists.
746 * @param __x Key of elements to be located.
747 * @return True if there is any element with the specified key.
748 */
749 bool
750 contains(const key_type& __x) const
751 { return _M_t.find(__x) != _M_t.end(); }
752
753 template<typename _Kt>
754 auto
755 contains(const _Kt& __x) const
756 -> decltype(_M_t._M_find_tr(__x), void(), true)
757 { return _M_t._M_find_tr(__x) != _M_t.end(); }
758 ///@}
759#endif
760
761 // _GLIBCXX_RESOLVE_LIB_DEFECTS
762 // 214. set::find() missing const overload
763 ///@{
764 /**
765 * @brief Tries to locate an element in a %set.
766 * @param __x Element to be located.
767 * @return Iterator pointing to sought-after element, or end() if not
768 * found.
769 *
770 * This function takes a key and tries to locate the element with which
771 * the key matches. If successful the function returns an iterator
772 * pointing to the sought after element. If unsuccessful it returns the
773 * past-the-end ( @c end() ) iterator.
774 */
775 iterator
776 find(const key_type& __x)
777 { return _M_t.find(__x); }
778
779 const_iterator
780 find(const key_type& __x) const
781 { return _M_t.find(__x); }
782
783#if __cplusplus > 201103L
784 template<typename _Kt>
785 auto
786 find(const _Kt& __x)
787 -> decltype(iterator{_M_t._M_find_tr(__x)})
788 { return iterator{_M_t._M_find_tr(__x)}; }
789
790 template<typename _Kt>
791 auto
792 find(const _Kt& __x) const
793 -> decltype(const_iterator{_M_t._M_find_tr(__x)})
794 { return const_iterator{_M_t._M_find_tr(__x)}; }
795#endif
796 ///@}
797
798 ///@{
799 /**
800 * @brief Finds the beginning of a subsequence matching given key.
801 * @param __x Key to be located.
802 * @return Iterator pointing to first element equal to or greater
803 * than key, or end().
804 *
805 * This function returns the first element of a subsequence of elements
806 * that matches the given key. If unsuccessful it returns an iterator
807 * pointing to the first element that has a greater value than given key
808 * or end() if no such element exists.
809 */
810 iterator
811 lower_bound(const key_type& __x)
812 { return _M_t.lower_bound(__x); }
813
814 const_iterator
815 lower_bound(const key_type& __x) const
816 { return _M_t.lower_bound(__x); }
817
818#if __cplusplus > 201103L
819 template<typename _Kt>
820 auto
821 lower_bound(const _Kt& __x)
822 -> decltype(iterator(_M_t._M_lower_bound_tr(__x)))
823 { return iterator(_M_t._M_lower_bound_tr(__x)); }
824
825 template<typename _Kt>
826 auto
827 lower_bound(const _Kt& __x) const
828 -> decltype(iterator(_M_t._M_lower_bound_tr(__x)))
829 { return iterator(_M_t._M_lower_bound_tr(__x)); }
830#endif
831 ///@}
832
833 ///@{
834 /**
835 * @brief Finds the end of a subsequence matching given key.
836 * @param __x Key to be located.
837 * @return Iterator pointing to the first element
838 * greater than key, or end().
839 */
840 iterator
841 upper_bound(const key_type& __x)
842 { return _M_t.upper_bound(__x); }
843
844 const_iterator
845 upper_bound(const key_type& __x) const
846 { return _M_t.upper_bound(__x); }
847
848#if __cplusplus > 201103L
849 template<typename _Kt>
850 auto
851 upper_bound(const _Kt& __x)
852 -> decltype(iterator(_M_t._M_upper_bound_tr(__x)))
853 { return iterator(_M_t._M_upper_bound_tr(__x)); }
854
855 template<typename _Kt>
856 auto
857 upper_bound(const _Kt& __x) const
858 -> decltype(iterator(_M_t._M_upper_bound_tr(__x)))
859 { return iterator(_M_t._M_upper_bound_tr(__x)); }
860#endif
861 ///@}
862
863 ///@{
864 /**
865 * @brief Finds a subsequence matching given key.
866 * @param __x Key to be located.
867 * @return Pair of iterators that possibly points to the subsequence
868 * matching given key.
869 *
870 * This function is equivalent to
871 * @code
872 * std::make_pair(c.lower_bound(val),
873 * c.upper_bound(val))
874 * @endcode
875 * (but is faster than making the calls separately).
876 *
877 * This function probably only makes sense for multisets.
878 */
879 std::pair<iterator, iterator>
880 equal_range(const key_type& __x)
881 { return _M_t.equal_range(__x); }
882
883 std::pair<const_iterator, const_iterator>
884 equal_range(const key_type& __x) const
885 { return _M_t.equal_range(__x); }
886
887#if __cplusplus > 201103L
888 template<typename _Kt>
889 auto
890 equal_range(const _Kt& __x)
891 -> decltype(pair<iterator, iterator>(_M_t._M_equal_range_tr(__x)))
892 { return pair<iterator, iterator>(_M_t._M_equal_range_tr(__x)); }
893
894 template<typename _Kt>
895 auto
896 equal_range(const _Kt& __x) const
897 -> decltype(pair<iterator, iterator>(_M_t._M_equal_range_tr(__x)))
898 { return pair<iterator, iterator>(_M_t._M_equal_range_tr(__x)); }
899#endif
900 ///@}
901
902 template<typename _K1, typename _C1, typename _A1>
903 friend bool
904 operator==(const multiset<_K1, _C1, _A1>&,
905 const multiset<_K1, _C1, _A1>&);
906
907#if __cpp_lib_three_way_comparison
908 template<typename _K1, typename _C1, typename _A1>
909 friend __detail::__synth3way_t<_K1>
910 operator<=>(const multiset<_K1, _C1, _A1>&,
911 const multiset<_K1, _C1, _A1>&);
912#else
913 template<typename _K1, typename _C1, typename _A1>
914 friend bool
915 operator< (const multiset<_K1, _C1, _A1>&,
916 const multiset<_K1, _C1, _A1>&);
917#endif
918 };
919
920#if __cpp_deduction_guides >= 201606
921
922 template<typename _InputIterator,
923 typename _Compare =
924 less<typename iterator_traits<_InputIterator>::value_type>,
925 typename _Allocator =
926 allocator<typename iterator_traits<_InputIterator>::value_type>,
927 typename = _RequireInputIter<_InputIterator>,
928 typename = _RequireNotAllocator<_Compare>,
929 typename = _RequireAllocator<_Allocator>>
930 multiset(_InputIterator, _InputIterator,
931 _Compare = _Compare(), _Allocator = _Allocator())
932 -> multiset<typename iterator_traits<_InputIterator>::value_type,
933 _Compare, _Allocator>;
934
935 template<typename _Key,
936 typename _Compare = less<_Key>,
937 typename _Allocator = allocator<_Key>,
938 typename = _RequireNotAllocator<_Compare>,
939 typename = _RequireAllocator<_Allocator>>
940 multiset(initializer_list<_Key>,
941 _Compare = _Compare(), _Allocator = _Allocator())
942 -> multiset<_Key, _Compare, _Allocator>;
943
944 template<typename _InputIterator, typename _Allocator,
945 typename = _RequireInputIter<_InputIterator>,
946 typename = _RequireAllocator<_Allocator>>
947 multiset(_InputIterator, _InputIterator, _Allocator)
948 -> multiset<typename iterator_traits<_InputIterator>::value_type,
949 less<typename iterator_traits<_InputIterator>::value_type>,
950 _Allocator>;
951
952 template<typename _Key, typename _Allocator,
953 typename = _RequireAllocator<_Allocator>>
954 multiset(initializer_list<_Key>, _Allocator)
955 -> multiset<_Key, less<_Key>, _Allocator>;
956
957#endif // deduction guides
958
959 /**
960 * @brief Multiset equality comparison.
961 * @param __x A %multiset.
962 * @param __y A %multiset of the same type as @a __x.
963 * @return True iff the size and elements of the multisets are equal.
964 *
965 * This is an equivalence relation. It is linear in the size of the
966 * multisets.
967 * Multisets are considered equivalent if their sizes are equal, and if
968 * corresponding elements compare equal.
969 */
970 template<typename _Key, typename _Compare, typename _Alloc>
971 inline bool
972 operator==(const multiset<_Key, _Compare, _Alloc>& __x,
973 const multiset<_Key, _Compare, _Alloc>& __y)
974 { return __x._M_t == __y._M_t; }
975
976#if __cpp_lib_three_way_comparison
977 /**
978 * @brief Multiset ordering relation.
979 * @param __x A `multiset`.
980 * @param __y A `multiset` of the same type as `x`.
981 * @return A value indicating whether `__x` is less than, equal to,
982 * greater than, or incomparable with `__y`.
983 *
984 * This is a total ordering relation. It is linear in the size of the
985 * maps. The elements must be comparable with @c <.
986 *
987 * See `std::lexicographical_compare_three_way()` for how the determination
988 * is made. This operator is used to synthesize relational operators like
989 * `<` and `>=` etc.
990 */
991 template<typename _Key, typename _Compare, typename _Alloc>
992 inline __detail::__synth3way_t<_Key>
993 operator<=>(const multiset<_Key, _Compare, _Alloc>& __x,
994 const multiset<_Key, _Compare, _Alloc>& __y)
995 { return __x._M_t <=> __y._M_t; }
996#else
997 /**
998 * @brief Multiset ordering relation.
999 * @param __x A %multiset.
1000 * @param __y A %multiset of the same type as @a __x.
1001 * @return True iff @a __x is lexicographically less than @a __y.
1002 *
1003 * This is a total ordering relation. It is linear in the size of the
1004 * sets. The elements must be comparable with @c <.
1005 *
1006 * See std::lexicographical_compare() for how the determination is made.
1007 */
1008 template<typename _Key, typename _Compare, typename _Alloc>
1009 inline bool
1010 operator<(const multiset<_Key, _Compare, _Alloc>& __x,
1011 const multiset<_Key, _Compare, _Alloc>& __y)
1012 { return __x._M_t < __y._M_t; }
1013
1014 /// Returns !(x == y).
1015 template<typename _Key, typename _Compare, typename _Alloc>
1016 inline bool
1017 operator!=(const multiset<_Key, _Compare, _Alloc>& __x,
1018 const multiset<_Key, _Compare, _Alloc>& __y)
1019 { return !(__x == __y); }
1020
1021 /// Returns y < x.
1022 template<typename _Key, typename _Compare, typename _Alloc>
1023 inline bool
1024 operator>(const multiset<_Key,_Compare,_Alloc>& __x,
1025 const multiset<_Key,_Compare,_Alloc>& __y)
1026 { return __y < __x; }
1027
1028 /// Returns !(y < x)
1029 template<typename _Key, typename _Compare, typename _Alloc>
1030 inline bool
1031 operator<=(const multiset<_Key, _Compare, _Alloc>& __x,
1032 const multiset<_Key, _Compare, _Alloc>& __y)
1033 { return !(__y < __x); }
1034
1035 /// Returns !(x < y)
1036 template<typename _Key, typename _Compare, typename _Alloc>
1037 inline bool
1038 operator>=(const multiset<_Key, _Compare, _Alloc>& __x,
1039 const multiset<_Key, _Compare, _Alloc>& __y)
1040 { return !(__x < __y); }
1041#endif // three-way comparison
1042
1043 /// See std::multiset::swap().
1044 template<typename _Key, typename _Compare, typename _Alloc>
1045 inline void
1046 swap(multiset<_Key, _Compare, _Alloc>& __x,
1047 multiset<_Key, _Compare, _Alloc>& __y)
1048 _GLIBCXX_NOEXCEPT_IF(noexcept(__x.swap(__y)))
1049 { __x.swap(__y); }
1050
1051_GLIBCXX_END_NAMESPACE_CONTAINER
1052
1053#if __cplusplus > 201402L
1054 // Allow std::multiset access to internals of compatible sets.
1055 template<typename _Val, typename _Cmp1, typename _Alloc, typename _Cmp2>
1056 struct
1057 _Rb_tree_merge_helper<_GLIBCXX_STD_C::multiset<_Val, _Cmp1, _Alloc>,
1058 _Cmp2>
1059 {
1060 private:
1061 friend class _GLIBCXX_STD_C::multiset<_Val, _Cmp1, _Alloc>;
1062
1063 static auto&
1064 _S_get_tree(_GLIBCXX_STD_C::set<_Val, _Cmp2, _Alloc>& __set)
1065 { return __set._M_t; }
1066
1067 static auto&
1068 _S_get_tree(_GLIBCXX_STD_C::multiset<_Val, _Cmp2, _Alloc>& __set)
1069 { return __set._M_t; }
1070 };
1071#endif // C++17
1072
1073_GLIBCXX_END_NAMESPACE_VERSION
1074} // namespace std
1075
1076#endif /* _STL_MULTISET_H */
1077