1 // Multimap 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_multimap.h
52 * This is an internal header file, included by other library headers.
53 * Do not attempt to use it directly. @headername{map}
54 */
55
56 #ifndef _STL_MULTIMAP_H
57 #define _STL_MULTIMAP_H 1
58
59 #include <bits/concept_check.h>
60 #if __cplusplus >= 201103L
61 #include <initializer_list>
62 #endif
63
_GLIBCXX_VISIBILITY(default)64 namespace std _GLIBCXX_VISIBILITY(default)
65 {
66 _GLIBCXX_BEGIN_NAMESPACE_VERSION
67 _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
68
69 template <typename _Key, typename _Tp, typename _Compare, typename _Alloc>
70 class map;
71
72 /**
73 * @brief A standard container made up of (key,value) pairs, which can be
74 * retrieved based on a key, in logarithmic time.
75 *
76 * @ingroup associative_containers
77 *
78 * @tparam _Key Type of key objects.
79 * @tparam _Tp Type of mapped objects.
80 * @tparam _Compare Comparison function object type, defaults to less<_Key>.
81 * @tparam _Alloc Allocator type, defaults to
82 * allocator<pair<const _Key, _Tp>.
83 *
84 * Meets the requirements of a <a href="tables.html#65">container</a>, a
85 * <a href="tables.html#66">reversible container</a>, and an
86 * <a href="tables.html#69">associative container</a> (using equivalent
87 * keys). For a @c multimap<Key,T> the key_type is Key, the mapped_type
88 * is T, and the value_type is std::pair<const Key,T>.
89 *
90 * Multimaps support bidirectional iterators.
91 *
92 * The private tree data is declared exactly the same way for map and
93 * multimap; the distinction is made entirely in how the tree functions are
94 * called (*_unique versus *_equal, same as the standard).
95 */
96 template <typename _Key, typename _Tp,
97 typename _Compare = std::less<_Key>,
98 typename _Alloc = std::allocator<std::pair<const _Key, _Tp> > >
99 class multimap
100 {
101 public:
102 typedef _Key key_type;
103 typedef _Tp mapped_type;
104 typedef std::pair<const _Key, _Tp> value_type;
105 typedef _Compare key_compare;
106 typedef _Alloc allocator_type;
107
108 private:
109 #ifdef _GLIBCXX_CONCEPT_CHECKS
110 // concept requirements
111 typedef typename _Alloc::value_type _Alloc_value_type;
112 # if __cplusplus < 201103L
113 __glibcxx_class_requires(_Tp, _SGIAssignableConcept)
114 # endif
115 __glibcxx_class_requires4(_Compare, bool, _Key, _Key,
116 _BinaryFunctionConcept)
117 __glibcxx_class_requires2(value_type, _Alloc_value_type, _SameTypeConcept)
118 #endif
119
120 #if __cplusplus >= 201103L
121 #if __cplusplus > 201703L || defined __STRICT_ANSI__
122 static_assert(is_same<typename _Alloc::value_type, value_type>::value,
123 "std::multimap must have the same value_type as its allocator");
124 #endif
125 #endif
126
127 public:
128 class value_compare
129 : public std::binary_function<value_type, value_type, bool>
130 {
131 friend class multimap<_Key, _Tp, _Compare, _Alloc>;
132 protected:
133 _Compare comp;
134
135 value_compare(_Compare __c)
136 : comp(__c) { }
137
138 public:
139 bool operator()(const value_type& __x, const value_type& __y) const
140 { return comp(__x.first, __y.first); }
141 };
142
143 private:
144 /// This turns a red-black tree into a [multi]map.
145 typedef typename __gnu_cxx::__alloc_traits<_Alloc>::template
146 rebind<value_type>::other _Pair_alloc_type;
147
148 typedef _Rb_tree<key_type, value_type, _Select1st<value_type>,
149 key_compare, _Pair_alloc_type> _Rep_type;
150 /// The actual tree structure.
151 _Rep_type _M_t;
152
153 typedef __gnu_cxx::__alloc_traits<_Pair_alloc_type> _Alloc_traits;
154
155 public:
156 // many of these are specified differently in ISO, but the following are
157 // "functionally equivalent"
158 typedef typename _Alloc_traits::pointer pointer;
159 typedef typename _Alloc_traits::const_pointer const_pointer;
160 typedef typename _Alloc_traits::reference reference;
161 typedef typename _Alloc_traits::const_reference const_reference;
162 typedef typename _Rep_type::iterator iterator;
163 typedef typename _Rep_type::const_iterator const_iterator;
164 typedef typename _Rep_type::size_type size_type;
165 typedef typename _Rep_type::difference_type difference_type;
166 typedef typename _Rep_type::reverse_iterator reverse_iterator;
167 typedef typename _Rep_type::const_reverse_iterator const_reverse_iterator;
168
169 #if __cplusplus > 201402L
170 using node_type = typename _Rep_type::node_type;
171 #endif
172
173 // [23.3.2] construct/copy/destroy
174 // (get_allocator() is also listed in this section)
175
176 /**
177 * @brief Default constructor creates no elements.
178 */
179 #if __cplusplus < 201103L
180 multimap() : _M_t() { }
181 #else
182 multimap() = default;
183 #endif
184
185 /**
186 * @brief Creates a %multimap with no elements.
187 * @param __comp A comparison object.
188 * @param __a An allocator object.
189 */
190 explicit
191 multimap(const _Compare& __comp,
192 const allocator_type& __a = allocator_type())
193 : _M_t(__comp, _Pair_alloc_type(__a)) { }
194
195 /**
196 * @brief %Multimap copy constructor.
197 *
198 * Whether the allocator is copied depends on the allocator traits.
199 */
200 #if __cplusplus < 201103L
201 multimap(const multimap& __x)
202 : _M_t(__x._M_t) { }
203 #else
204 multimap(const multimap&) = default;
205
206 /**
207 * @brief %Multimap move constructor.
208 *
209 * The newly-created %multimap contains the exact contents of the
210 * moved instance. The moved instance is a valid, but unspecified
211 * %multimap.
212 */
213 multimap(multimap&&) = default;
214
215 /**
216 * @brief Builds a %multimap from an initializer_list.
217 * @param __l An initializer_list.
218 * @param __comp A comparison functor.
219 * @param __a An allocator object.
220 *
221 * Create a %multimap consisting of copies of the elements from
222 * the initializer_list. This is linear in N if the list is already
223 * sorted, and NlogN otherwise (where N is @a __l.size()).
224 */
225 multimap(initializer_list<value_type> __l,
226 const _Compare& __comp = _Compare(),
227 const allocator_type& __a = allocator_type())
228 : _M_t(__comp, _Pair_alloc_type(__a))
229 { _M_t._M_insert_range_equal(__l.begin(), __l.end()); }
230
231 /// Allocator-extended default constructor.
232 explicit
233 multimap(const allocator_type& __a)
234 : _M_t(_Pair_alloc_type(__a)) { }
235
236 /// Allocator-extended copy constructor.
237 multimap(const multimap& __m, const allocator_type& __a)
238 : _M_t(__m._M_t, _Pair_alloc_type(__a)) { }
239
240 /// Allocator-extended move constructor.
241 multimap(multimap&& __m, const allocator_type& __a)
242 noexcept(is_nothrow_copy_constructible<_Compare>::value
243 && _Alloc_traits::_S_always_equal())
244 : _M_t(std::move(__m._M_t), _Pair_alloc_type(__a)) { }
245
246 /// Allocator-extended initialier-list constructor.
247 multimap(initializer_list<value_type> __l, const allocator_type& __a)
248 : _M_t(_Pair_alloc_type(__a))
249 { _M_t._M_insert_range_equal(__l.begin(), __l.end()); }
250
251 /// Allocator-extended range constructor.
252 template<typename _InputIterator>
253 multimap(_InputIterator __first, _InputIterator __last,
254 const allocator_type& __a)
255 : _M_t(_Pair_alloc_type(__a))
256 { _M_t._M_insert_range_equal(__first, __last); }
257 #endif
258
259 /**
260 * @brief Builds a %multimap from a range.
261 * @param __first An input iterator.
262 * @param __last An input iterator.
263 *
264 * Create a %multimap consisting of copies of the elements from
265 * [__first,__last). This is linear in N if the range is already sorted,
266 * and NlogN otherwise (where N is distance(__first,__last)).
267 */
268 template<typename _InputIterator>
269 multimap(_InputIterator __first, _InputIterator __last)
270 : _M_t()
271 { _M_t._M_insert_range_equal(__first, __last); }
272
273 /**
274 * @brief Builds a %multimap from a range.
275 * @param __first An input iterator.
276 * @param __last An input iterator.
277 * @param __comp A comparison functor.
278 * @param __a An allocator object.
279 *
280 * Create a %multimap consisting of copies of the elements from
281 * [__first,__last). This is linear in N if the range is already sorted,
282 * and NlogN otherwise (where N is distance(__first,__last)).
283 */
284 template<typename _InputIterator>
285 multimap(_InputIterator __first, _InputIterator __last,
286 const _Compare& __comp,
287 const allocator_type& __a = allocator_type())
288 : _M_t(__comp, _Pair_alloc_type(__a))
289 { _M_t._M_insert_range_equal(__first, __last); }
290
291 #if __cplusplus >= 201103L
292 /**
293 * The dtor only erases the elements, and note that if the elements
294 * themselves are pointers, the pointed-to memory is not touched in any
295 * way. Managing the pointer is the user's responsibility.
296 */
297 ~multimap() = default;
298 #endif
299
300 /**
301 * @brief %Multimap assignment operator.
302 *
303 * Whether the allocator is copied depends on the allocator traits.
304 */
305 #if __cplusplus < 201103L
306 multimap&
307 operator=(const multimap& __x)
308 {
309 _M_t = __x._M_t;
310 return *this;
311 }
312 #else
313 multimap&
314 operator=(const multimap&) = default;
315
316 /// Move assignment operator.
317 multimap&
318 operator=(multimap&&) = default;
319
320 /**
321 * @brief %Multimap list assignment operator.
322 * @param __l An initializer_list.
323 *
324 * This function fills a %multimap with copies of the elements
325 * in the initializer list @a __l.
326 *
327 * Note that the assignment completely changes the %multimap and
328 * that the resulting %multimap's size is the same as the number
329 * of elements assigned.
330 */
331 multimap&
332 operator=(initializer_list<value_type> __l)
333 {
334 _M_t._M_assign_equal(__l.begin(), __l.end());
335 return *this;
336 }
337 #endif
338
339 /// Get a copy of the memory allocation object.
340 allocator_type
341 get_allocator() const _GLIBCXX_NOEXCEPT
342 { return allocator_type(_M_t.get_allocator()); }
343
344 // iterators
345 /**
346 * Returns a read/write iterator that points to the first pair in the
347 * %multimap. Iteration is done in ascending order according to the
348 * keys.
349 */
350 iterator
351 begin() _GLIBCXX_NOEXCEPT
352 { return _M_t.begin(); }
353
354 /**
355 * Returns a read-only (constant) iterator that points to the first pair
356 * in the %multimap. Iteration is done in ascending order according to
357 * the keys.
358 */
359 const_iterator
360 begin() const _GLIBCXX_NOEXCEPT
361 { return _M_t.begin(); }
362
363 /**
364 * Returns a read/write iterator that points one past the last pair in
365 * the %multimap. Iteration is done in ascending order according to the
366 * keys.
367 */
368 iterator
369 end() _GLIBCXX_NOEXCEPT
370 { return _M_t.end(); }
371
372 /**
373 * Returns a read-only (constant) iterator that points one past the last
374 * pair in the %multimap. Iteration is done in ascending order according
375 * to the keys.
376 */
377 const_iterator
378 end() const _GLIBCXX_NOEXCEPT
379 { return _M_t.end(); }
380
381 /**
382 * Returns a read/write reverse iterator that points to the last pair in
383 * the %multimap. Iteration is done in descending order according to the
384 * keys.
385 */
386 reverse_iterator
387 rbegin() _GLIBCXX_NOEXCEPT
388 { return _M_t.rbegin(); }
389
390 /**
391 * Returns a read-only (constant) reverse iterator that points to the
392 * last pair in the %multimap. Iteration is done in descending order
393 * according to the keys.
394 */
395 const_reverse_iterator
396 rbegin() const _GLIBCXX_NOEXCEPT
397 { return _M_t.rbegin(); }
398
399 /**
400 * Returns a read/write reverse iterator that points to one before the
401 * first pair in the %multimap. Iteration is done in descending order
402 * according to the keys.
403 */
404 reverse_iterator
405 rend() _GLIBCXX_NOEXCEPT
406 { return _M_t.rend(); }
407
408 /**
409 * Returns a read-only (constant) reverse iterator that points to one
410 * before the first pair in the %multimap. Iteration is done in
411 * descending order according to the keys.
412 */
413 const_reverse_iterator
414 rend() const _GLIBCXX_NOEXCEPT
415 { return _M_t.rend(); }
416
417 #if __cplusplus >= 201103L
418 /**
419 * Returns a read-only (constant) iterator that points to the first pair
420 * in the %multimap. Iteration is done in ascending order according to
421 * the keys.
422 */
423 const_iterator
424 cbegin() const noexcept
425 { return _M_t.begin(); }
426
427 /**
428 * Returns a read-only (constant) iterator that points one past the last
429 * pair in the %multimap. Iteration is done in ascending order according
430 * to the keys.
431 */
432 const_iterator
433 cend() const noexcept
434 { return _M_t.end(); }
435
436 /**
437 * Returns a read-only (constant) reverse iterator that points to the
438 * last pair in the %multimap. Iteration is done in descending order
439 * according to the keys.
440 */
441 const_reverse_iterator
442 crbegin() const noexcept
443 { return _M_t.rbegin(); }
444
445 /**
446 * Returns a read-only (constant) reverse iterator that points to one
447 * before the first pair in the %multimap. Iteration is done in
448 * descending order according to the keys.
449 */
450 const_reverse_iterator
451 crend() const noexcept
452 { return _M_t.rend(); }
453 #endif
454
455 // capacity
456 /** Returns true if the %multimap is empty. */
457 _GLIBCXX_NODISCARD bool
458 empty() const _GLIBCXX_NOEXCEPT
459 { return _M_t.empty(); }
460
461 /** Returns the size of the %multimap. */
462 size_type
463 size() const _GLIBCXX_NOEXCEPT
464 { return _M_t.size(); }
465
466 /** Returns the maximum size of the %multimap. */
467 size_type
468 max_size() const _GLIBCXX_NOEXCEPT
469 { return _M_t.max_size(); }
470
471 // modifiers
472 #if __cplusplus >= 201103L
473 /**
474 * @brief Build and insert a std::pair into the %multimap.
475 *
476 * @param __args Arguments used to generate a new pair instance (see
477 * std::piecewise_contruct for passing arguments to each
478 * part of the pair constructor).
479 *
480 * @return An iterator that points to the inserted (key,value) pair.
481 *
482 * This function builds and inserts a (key, value) %pair into the
483 * %multimap.
484 * Contrary to a std::map the %multimap does not rely on unique keys and
485 * thus multiple pairs with the same key can be inserted.
486 *
487 * Insertion requires logarithmic time.
488 */
489 template<typename... _Args>
490 iterator
491 emplace(_Args&&... __args)
492 { return _M_t._M_emplace_equal(std::forward<_Args>(__args)...); }
493
494 /**
495 * @brief Builds and inserts a std::pair into the %multimap.
496 *
497 * @param __pos An iterator that serves as a hint as to where the pair
498 * should be inserted.
499 * @param __args Arguments used to generate a new pair instance (see
500 * std::piecewise_contruct for passing arguments to each
501 * part of the pair constructor).
502 * @return An iterator that points to the inserted (key,value) pair.
503 *
504 * This function inserts a (key, value) pair into the %multimap.
505 * Contrary to a std::map the %multimap does not rely on unique keys and
506 * thus multiple pairs with the same key can be inserted.
507 * Note that the first parameter is only a hint and can potentially
508 * improve the performance of the insertion process. A bad hint would
509 * cause no gains in efficiency.
510 *
511 * For more on @a hinting, see:
512 * https://gcc.gnu.org/onlinedocs/libstdc++/manual/associative.html#containers.associative.insert_hints
513 *
514 * Insertion requires logarithmic time (if the hint is not taken).
515 */
516 template<typename... _Args>
517 iterator
518 emplace_hint(const_iterator __pos, _Args&&... __args)
519 {
520 return _M_t._M_emplace_hint_equal(__pos,
521 std::forward<_Args>(__args)...);
522 }
523 #endif
524
525 /**
526 * @brief Inserts a std::pair into the %multimap.
527 * @param __x Pair to be inserted (see std::make_pair for easy creation
528 * of pairs).
529 * @return An iterator that points to the inserted (key,value) pair.
530 *
531 * This function inserts a (key, value) pair into the %multimap.
532 * Contrary to a std::map the %multimap does not rely on unique keys and
533 * thus multiple pairs with the same key can be inserted.
534 *
535 * Insertion requires logarithmic time.
536 * @{
537 */
538 iterator
539 insert(const value_type& __x)
540 { return _M_t._M_insert_equal(__x); }
541
542 #if __cplusplus >= 201103L
543 // _GLIBCXX_RESOLVE_LIB_DEFECTS
544 // 2354. Unnecessary copying when inserting into maps with braced-init
545 iterator
546 insert(value_type&& __x)
547 { return _M_t._M_insert_equal(std::move(__x)); }
548
549 template<typename _Pair>
550 __enable_if_t<is_constructible<value_type, _Pair>::value, iterator>
551 insert(_Pair&& __x)
552 { return _M_t._M_emplace_equal(std::forward<_Pair>(__x)); }
553 #endif
554 /// @}
555
556 /**
557 * @brief Inserts a std::pair into the %multimap.
558 * @param __position An iterator that serves as a hint as to where the
559 * pair should be inserted.
560 * @param __x Pair to be inserted (see std::make_pair for easy creation
561 * of pairs).
562 * @return An iterator that points to the inserted (key,value) pair.
563 *
564 * This function inserts a (key, value) pair into the %multimap.
565 * Contrary to a std::map the %multimap does not rely on unique keys and
566 * thus multiple pairs with the same key can be inserted.
567 * Note that the first parameter is only a hint and can potentially
568 * improve the performance of the insertion process. A bad hint would
569 * cause no gains in efficiency.
570 *
571 * For more on @a hinting, see:
572 * https://gcc.gnu.org/onlinedocs/libstdc++/manual/associative.html#containers.associative.insert_hints
573 *
574 * Insertion requires logarithmic time (if the hint is not taken).
575 * @{
576 */
577 iterator
578 #if __cplusplus >= 201103L
579 insert(const_iterator __position, const value_type& __x)
580 #else
581 insert(iterator __position, const value_type& __x)
582 #endif
583 { return _M_t._M_insert_equal_(__position, __x); }
584
585 #if __cplusplus >= 201103L
586 // _GLIBCXX_RESOLVE_LIB_DEFECTS
587 // 2354. Unnecessary copying when inserting into maps with braced-init
588 iterator
589 insert(const_iterator __position, value_type&& __x)
590 { return _M_t._M_insert_equal_(__position, std::move(__x)); }
591
592 template<typename _Pair>
593 __enable_if_t<is_constructible<value_type, _Pair&&>::value, iterator>
594 insert(const_iterator __position, _Pair&& __x)
595 {
596 return _M_t._M_emplace_hint_equal(__position,
597 std::forward<_Pair>(__x));
598 }
599 #endif
600 /// @}
601
602 /**
603 * @brief A template function that attempts to insert a range
604 * of elements.
605 * @param __first Iterator pointing to the start of the range to be
606 * inserted.
607 * @param __last Iterator pointing to the end of the range.
608 *
609 * Complexity similar to that of the range constructor.
610 */
611 template<typename _InputIterator>
612 void
613 insert(_InputIterator __first, _InputIterator __last)
614 { _M_t._M_insert_range_equal(__first, __last); }
615
616 #if __cplusplus >= 201103L
617 /**
618 * @brief Attempts to insert a list of std::pairs into the %multimap.
619 * @param __l A std::initializer_list<value_type> of pairs to be
620 * inserted.
621 *
622 * Complexity similar to that of the range constructor.
623 */
624 void
625 insert(initializer_list<value_type> __l)
626 { this->insert(__l.begin(), __l.end()); }
627 #endif
628
629 #if __cplusplus > 201402L
630 /// Extract a node.
631 node_type
632 extract(const_iterator __pos)
633 {
634 __glibcxx_assert(__pos != end());
635 return _M_t.extract(__pos);
636 }
637
638 /// Extract a node.
639 node_type
640 extract(const key_type& __x)
641 { return _M_t.extract(__x); }
642
643 /// Re-insert an extracted node.
644 iterator
645 insert(node_type&& __nh)
646 { return _M_t._M_reinsert_node_equal(std::move(__nh)); }
647
648 /// Re-insert an extracted node.
649 iterator
650 insert(const_iterator __hint, node_type&& __nh)
651 { return _M_t._M_reinsert_node_hint_equal(__hint, std::move(__nh)); }
652
653 template<typename, typename>
654 friend class std::_Rb_tree_merge_helper;
655
656 template<typename _Cmp2>
657 void
658 merge(multimap<_Key, _Tp, _Cmp2, _Alloc>& __source)
659 {
660 using _Merge_helper = _Rb_tree_merge_helper<multimap, _Cmp2>;
661 _M_t._M_merge_equal(_Merge_helper::_S_get_tree(__source));
662 }
663
664 template<typename _Cmp2>
665 void
666 merge(multimap<_Key, _Tp, _Cmp2, _Alloc>&& __source)
667 { merge(__source); }
668
669 template<typename _Cmp2>
670 void
671 merge(map<_Key, _Tp, _Cmp2, _Alloc>& __source)
672 {
673 using _Merge_helper = _Rb_tree_merge_helper<multimap, _Cmp2>;
674 _M_t._M_merge_equal(_Merge_helper::_S_get_tree(__source));
675 }
676
677 template<typename _Cmp2>
678 void
679 merge(map<_Key, _Tp, _Cmp2, _Alloc>&& __source)
680 { merge(__source); }
681 #endif // C++17
682
683 #if __cplusplus >= 201103L
684 // _GLIBCXX_RESOLVE_LIB_DEFECTS
685 // DR 130. Associative erase should return an iterator.
686 /**
687 * @brief Erases an element from a %multimap.
688 * @param __position An iterator pointing to the element to be erased.
689 * @return An iterator pointing to the element immediately following
690 * @a position prior to the element being erased. If no such
691 * element exists, end() is returned.
692 *
693 * This function erases an element, pointed to by the given iterator,
694 * from a %multimap. Note that this function only erases the element,
695 * and that if the element is itself a pointer, the pointed-to memory is
696 * not touched in any way. Managing the pointer is the user's
697 * responsibility.
698 *
699 * @{
700 */
701 iterator
702 erase(const_iterator __position)
703 { return _M_t.erase(__position); }
704
705 // LWG 2059.
706 _GLIBCXX_ABI_TAG_CXX11
707 iterator
708 erase(iterator __position)
709 { return _M_t.erase(__position); }
710 /// @}
711 #else
712 /**
713 * @brief Erases an element from a %multimap.
714 * @param __position An iterator pointing to the element to be erased.
715 *
716 * This function erases an element, pointed to by the given iterator,
717 * from a %multimap. Note that this function only erases the element,
718 * and that if the element is itself a pointer, the pointed-to memory is
719 * not touched in any way. Managing the pointer is the user's
720 * responsibility.
721 */
722 void
723 erase(iterator __position)
724 { _M_t.erase(__position); }
725 #endif
726
727 /**
728 * @brief Erases elements according to the provided key.
729 * @param __x Key of element to be erased.
730 * @return The number of elements erased.
731 *
732 * This function erases all elements located by the given key from a
733 * %multimap.
734 * Note that this function only erases the element, and that if
735 * the element is itself a pointer, the pointed-to memory is not touched
736 * in any way. Managing the pointer is the user's responsibility.
737 */
738 size_type
739 erase(const key_type& __x)
740 { return _M_t.erase(__x); }
741
742 #if __cplusplus >= 201103L
743 // _GLIBCXX_RESOLVE_LIB_DEFECTS
744 // DR 130. Associative erase should return an iterator.
745 /**
746 * @brief Erases a [first,last) range of elements from a %multimap.
747 * @param __first Iterator pointing to the start of the range to be
748 * erased.
749 * @param __last Iterator pointing to the end of the range to be
750 * erased .
751 * @return The iterator @a __last.
752 *
753 * This function erases a sequence of elements from a %multimap.
754 * Note that this function only erases the elements, and that if
755 * the elements themselves are pointers, the pointed-to memory is not
756 * touched in any way. Managing the pointer is the user's
757 * responsibility.
758 */
759 iterator
760 erase(const_iterator __first, const_iterator __last)
761 { return _M_t.erase(__first, __last); }
762 #else
763 // _GLIBCXX_RESOLVE_LIB_DEFECTS
764 // DR 130. Associative erase should return an iterator.
765 /**
766 * @brief Erases a [first,last) range of elements from a %multimap.
767 * @param __first Iterator pointing to the start of the range to be
768 * erased.
769 * @param __last Iterator pointing to the end of the range to
770 * be erased.
771 *
772 * This function erases a sequence of elements from a %multimap.
773 * Note that this function only erases the elements, and that if
774 * the elements themselves are pointers, the pointed-to memory is not
775 * touched in any way. Managing the pointer is the user's
776 * responsibility.
777 */
778 void
779 erase(iterator __first, iterator __last)
780 { _M_t.erase(__first, __last); }
781 #endif
782
783 /**
784 * @brief Swaps data with another %multimap.
785 * @param __x A %multimap of the same element and allocator types.
786 *
787 * This exchanges the elements between two multimaps in constant time.
788 * (It is only swapping a pointer, an integer, and an instance of
789 * the @c Compare type (which itself is often stateless and empty), so it
790 * should be quite fast.)
791 * Note that the global std::swap() function is specialized such that
792 * std::swap(m1,m2) will feed to this function.
793 *
794 * Whether the allocators are swapped depends on the allocator traits.
795 */
796 void
797 swap(multimap& __x)
798 _GLIBCXX_NOEXCEPT_IF(__is_nothrow_swappable<_Compare>::value)
799 { _M_t.swap(__x._M_t); }
800
801 /**
802 * Erases all elements in a %multimap. Note that this function only
803 * erases the elements, and that if the elements themselves are pointers,
804 * the pointed-to memory is not touched in any way. Managing the pointer
805 * is the user's responsibility.
806 */
807 void
808 clear() _GLIBCXX_NOEXCEPT
809 { _M_t.clear(); }
810
811 // observers
812 /**
813 * Returns the key comparison object out of which the %multimap
814 * was constructed.
815 */
816 key_compare
817 key_comp() const
818 { return _M_t.key_comp(); }
819
820 /**
821 * Returns a value comparison object, built from the key comparison
822 * object out of which the %multimap was constructed.
823 */
824 value_compare
825 value_comp() const
826 { return value_compare(_M_t.key_comp()); }
827
828 // multimap operations
829
830 ///@{
831 /**
832 * @brief Tries to locate an element in a %multimap.
833 * @param __x Key of (key, value) pair to be located.
834 * @return Iterator pointing to sought-after element,
835 * or end() if not found.
836 *
837 * This function takes a key and tries to locate the element with which
838 * the key matches. If successful the function returns an iterator
839 * pointing to the sought after %pair. If unsuccessful it returns the
840 * past-the-end ( @c end() ) iterator.
841 */
842 iterator
843 find(const key_type& __x)
844 { return _M_t.find(__x); }
845
846 #if __cplusplus > 201103L
847 template<typename _Kt>
848 auto
849 find(const _Kt& __x) -> decltype(_M_t._M_find_tr(__x))
850 { return _M_t._M_find_tr(__x); }
851 #endif
852 ///@}
853
854 ///@{
855 /**
856 * @brief Tries to locate an element in a %multimap.
857 * @param __x Key of (key, value) pair to be located.
858 * @return Read-only (constant) iterator pointing to sought-after
859 * element, or end() if not found.
860 *
861 * This function takes a key and tries to locate the element with which
862 * the key matches. If successful the function returns a constant
863 * iterator pointing to the sought after %pair. If unsuccessful it
864 * returns the past-the-end ( @c end() ) iterator.
865 */
866 const_iterator
867 find(const key_type& __x) const
868 { return _M_t.find(__x); }
869
870 #if __cplusplus > 201103L
871 template<typename _Kt>
872 auto
873 find(const _Kt& __x) const -> decltype(_M_t._M_find_tr(__x))
874 { return _M_t._M_find_tr(__x); }
875 #endif
876 ///@}
877
878 ///@{
879 /**
880 * @brief Finds the number of elements with given key.
881 * @param __x Key of (key, value) pairs to be located.
882 * @return Number of elements with specified key.
883 */
884 size_type
885 count(const key_type& __x) const
886 { return _M_t.count(__x); }
887
888 #if __cplusplus > 201103L
889 template<typename _Kt>
890 auto
891 count(const _Kt& __x) const -> decltype(_M_t._M_count_tr(__x))
892 { return _M_t._M_count_tr(__x); }
893 #endif
894 ///@}
895
896 #if __cplusplus > 201703L
897 ///@{
898 /**
899 * @brief Finds whether an element with the given key exists.
900 * @param __x Key of (key, value) pairs to be located.
901 * @return True if there is any element with the specified key.
902 */
903 bool
904 contains(const key_type& __x) const
905 { return _M_t.find(__x) != _M_t.end(); }
906
907 template<typename _Kt>
908 auto
909 contains(const _Kt& __x) const
910 -> decltype(_M_t._M_find_tr(__x), void(), true)
911 { return _M_t._M_find_tr(__x) != _M_t.end(); }
912 ///@}
913 #endif
914
915 ///@{
916 /**
917 * @brief Finds the beginning of a subsequence matching given key.
918 * @param __x Key of (key, value) pair to be located.
919 * @return Iterator pointing to first element equal to or greater
920 * than key, or end().
921 *
922 * This function returns the first element of a subsequence of elements
923 * that matches the given key. If unsuccessful it returns an iterator
924 * pointing to the first element that has a greater value than given key
925 * or end() if no such element exists.
926 */
927 iterator
928 lower_bound(const key_type& __x)
929 { return _M_t.lower_bound(__x); }
930
931 #if __cplusplus > 201103L
932 template<typename _Kt>
933 auto
934 lower_bound(const _Kt& __x)
935 -> decltype(iterator(_M_t._M_lower_bound_tr(__x)))
936 { return iterator(_M_t._M_lower_bound_tr(__x)); }
937 #endif
938 ///@}
939
940 ///@{
941 /**
942 * @brief Finds the beginning of a subsequence matching given key.
943 * @param __x Key of (key, value) pair to be located.
944 * @return Read-only (constant) iterator pointing to first element
945 * equal to or greater than key, or end().
946 *
947 * This function returns the first element of a subsequence of
948 * elements that matches the given key. If unsuccessful the
949 * iterator will point to the next greatest element or, if no
950 * such greater element exists, to end().
951 */
952 const_iterator
953 lower_bound(const key_type& __x) const
954 { return _M_t.lower_bound(__x); }
955
956 #if __cplusplus > 201103L
957 template<typename _Kt>
958 auto
959 lower_bound(const _Kt& __x) const
960 -> decltype(const_iterator(_M_t._M_lower_bound_tr(__x)))
961 { return const_iterator(_M_t._M_lower_bound_tr(__x)); }
962 #endif
963 ///@}
964
965 ///@{
966 /**
967 * @brief Finds the end of a subsequence matching given key.
968 * @param __x Key of (key, value) pair to be located.
969 * @return Iterator pointing to the first element
970 * greater than key, or end().
971 */
972 iterator
973 upper_bound(const key_type& __x)
974 { return _M_t.upper_bound(__x); }
975
976 #if __cplusplus > 201103L
977 template<typename _Kt>
978 auto
979 upper_bound(const _Kt& __x)
980 -> decltype(iterator(_M_t._M_upper_bound_tr(__x)))
981 { return iterator(_M_t._M_upper_bound_tr(__x)); }
982 #endif
983 ///@}
984
985 ///@{
986 /**
987 * @brief Finds the end of a subsequence matching given key.
988 * @param __x Key of (key, value) pair to be located.
989 * @return Read-only (constant) iterator pointing to first iterator
990 * greater than key, or end().
991 */
992 const_iterator
993 upper_bound(const key_type& __x) const
994 { return _M_t.upper_bound(__x); }
995
996 #if __cplusplus > 201103L
997 template<typename _Kt>
998 auto
999 upper_bound(const _Kt& __x) const
1000 -> decltype(const_iterator(_M_t._M_upper_bound_tr(__x)))
1001 { return const_iterator(_M_t._M_upper_bound_tr(__x)); }
1002 #endif
1003 ///@}
1004
1005 ///@{
1006 /**
1007 * @brief Finds a subsequence matching given key.
1008 * @param __x Key of (key, value) pairs to be located.
1009 * @return Pair of iterators that possibly points to the subsequence
1010 * matching given key.
1011 *
1012 * This function is equivalent to
1013 * @code
1014 * std::make_pair(c.lower_bound(val),
1015 * c.upper_bound(val))
1016 * @endcode
1017 * (but is faster than making the calls separately).
1018 */
1019 std::pair<iterator, iterator>
1020 equal_range(const key_type& __x)
1021 { return _M_t.equal_range(__x); }
1022
1023 #if __cplusplus > 201103L
1024 template<typename _Kt>
1025 auto
1026 equal_range(const _Kt& __x)
1027 -> decltype(pair<iterator, iterator>(_M_t._M_equal_range_tr(__x)))
1028 { return pair<iterator, iterator>(_M_t._M_equal_range_tr(__x)); }
1029 #endif
1030 ///@}
1031
1032 ///@{
1033 /**
1034 * @brief Finds a subsequence matching given key.
1035 * @param __x Key of (key, value) pairs to be located.
1036 * @return Pair of read-only (constant) iterators that possibly points
1037 * to the subsequence matching given key.
1038 *
1039 * This function is equivalent to
1040 * @code
1041 * std::make_pair(c.lower_bound(val),
1042 * c.upper_bound(val))
1043 * @endcode
1044 * (but is faster than making the calls separately).
1045 */
1046 std::pair<const_iterator, const_iterator>
1047 equal_range(const key_type& __x) const
1048 { return _M_t.equal_range(__x); }
1049
1050 #if __cplusplus > 201103L
1051 template<typename _Kt>
1052 auto
1053 equal_range(const _Kt& __x) const
1054 -> decltype(pair<const_iterator, const_iterator>(
1055 _M_t._M_equal_range_tr(__x)))
1056 {
1057 return pair<const_iterator, const_iterator>(
1058 _M_t._M_equal_range_tr(__x));
1059 }
1060 #endif
1061 ///@}
1062
1063 template<typename _K1, typename _T1, typename _C1, typename _A1>
1064 friend bool
1065 operator==(const multimap<_K1, _T1, _C1, _A1>&,
1066 const multimap<_K1, _T1, _C1, _A1>&);
1067
1068 #if __cpp_lib_three_way_comparison
1069 template<typename _K1, typename _T1, typename _C1, typename _A1>
1070 friend __detail::__synth3way_t<pair<const _K1, _T1>>
1071 operator<=>(const multimap<_K1, _T1, _C1, _A1>&,
1072 const multimap<_K1, _T1, _C1, _A1>&);
1073 #else
1074 template<typename _K1, typename _T1, typename _C1, typename _A1>
1075 friend bool
1076 operator<(const multimap<_K1, _T1, _C1, _A1>&,
1077 const multimap<_K1, _T1, _C1, _A1>&);
1078 #endif
1079 };
1080
1081 #if __cpp_deduction_guides >= 201606
1082
1083 template<typename _InputIterator,
1084 typename _Compare = less<__iter_key_t<_InputIterator>>,
1085 typename _Allocator = allocator<__iter_to_alloc_t<_InputIterator>>,
1086 typename = _RequireInputIter<_InputIterator>,
1087 typename = _RequireNotAllocator<_Compare>,
1088 typename = _RequireAllocator<_Allocator>>
1089 multimap(_InputIterator, _InputIterator,
1090 _Compare = _Compare(), _Allocator = _Allocator())
1091 -> multimap<__iter_key_t<_InputIterator>, __iter_val_t<_InputIterator>,
1092 _Compare, _Allocator>;
1093
1094 template<typename _Key, typename _Tp, typename _Compare = less<_Key>,
1095 typename _Allocator = allocator<pair<const _Key, _Tp>>,
1096 typename = _RequireNotAllocator<_Compare>,
1097 typename = _RequireAllocator<_Allocator>>
1098 multimap(initializer_list<pair<_Key, _Tp>>,
1099 _Compare = _Compare(), _Allocator = _Allocator())
1100 -> multimap<_Key, _Tp, _Compare, _Allocator>;
1101
1102 template<typename _InputIterator, typename _Allocator,
1103 typename = _RequireInputIter<_InputIterator>,
1104 typename = _RequireAllocator<_Allocator>>
1105 multimap(_InputIterator, _InputIterator, _Allocator)
1106 -> multimap<__iter_key_t<_InputIterator>, __iter_val_t<_InputIterator>,
1107 less<__iter_key_t<_InputIterator>>, _Allocator>;
1108
1109 template<typename _Key, typename _Tp, typename _Allocator,
1110 typename = _RequireAllocator<_Allocator>>
1111 multimap(initializer_list<pair<_Key, _Tp>>, _Allocator)
1112 -> multimap<_Key, _Tp, less<_Key>, _Allocator>;
1113
1114 #endif // deduction guides
1115
1116 /**
1117 * @brief Multimap equality comparison.
1118 * @param __x A %multimap.
1119 * @param __y A %multimap of the same type as @a __x.
1120 * @return True iff the size and elements of the maps are equal.
1121 *
1122 * This is an equivalence relation. It is linear in the size of the
1123 * multimaps. Multimaps are considered equivalent if their sizes are equal,
1124 * and if corresponding elements compare equal.
1125 */
1126 template<typename _Key, typename _Tp, typename _Compare, typename _Alloc>
1127 inline bool
1128 operator==(const multimap<_Key, _Tp, _Compare, _Alloc>& __x,
1129 const multimap<_Key, _Tp, _Compare, _Alloc>& __y)
1130 { return __x._M_t == __y._M_t; }
1131
1132 #if __cpp_lib_three_way_comparison
1133 /**
1134 * @brief Multimap ordering relation.
1135 * @param __x A `multimap`.
1136 * @param __y A `multimap` of the same type as `x`.
1137 * @return A value indicating whether `__x` is less than, equal to,
1138 * greater than, or incomparable with `__y`.
1139 *
1140 * This is a total ordering relation. It is linear in the size of the
1141 * maps. The elements must be comparable with @c <.
1142 *
1143 * See `std::lexicographical_compare_three_way()` for how the determination
1144 * is made. This operator is used to synthesize relational operators like
1145 * `<` and `>=` etc.
1146 */
1147 template<typename _Key, typename _Tp, typename _Compare, typename _Alloc>
1148 inline __detail::__synth3way_t<pair<const _Key, _Tp>>
1149 operator<=>(const multimap<_Key, _Tp, _Compare, _Alloc>& __x,
1150 const multimap<_Key, _Tp, _Compare, _Alloc>& __y)
1151 { return __x._M_t <=> __y._M_t; }
1152 #else
1153 /**
1154 * @brief Multimap ordering relation.
1155 * @param __x A %multimap.
1156 * @param __y A %multimap of the same type as @a __x.
1157 * @return True iff @a x is lexicographically less than @a y.
1158 *
1159 * This is a total ordering relation. It is linear in the size of the
1160 * multimaps. The elements must be comparable with @c <.
1161 *
1162 * See std::lexicographical_compare() for how the determination is made.
1163 */
1164 template<typename _Key, typename _Tp, typename _Compare, typename _Alloc>
1165 inline bool
1166 operator<(const multimap<_Key, _Tp, _Compare, _Alloc>& __x,
1167 const multimap<_Key, _Tp, _Compare, _Alloc>& __y)
1168 { return __x._M_t < __y._M_t; }
1169
1170 /// Based on operator==
1171 template<typename _Key, typename _Tp, typename _Compare, typename _Alloc>
1172 inline bool
1173 operator!=(const multimap<_Key, _Tp, _Compare, _Alloc>& __x,
1174 const multimap<_Key, _Tp, _Compare, _Alloc>& __y)
1175 { return !(__x == __y); }
1176
1177 /// Based on operator<
1178 template<typename _Key, typename _Tp, typename _Compare, typename _Alloc>
1179 inline bool
1180 operator>(const multimap<_Key, _Tp, _Compare, _Alloc>& __x,
1181 const multimap<_Key, _Tp, _Compare, _Alloc>& __y)
1182 { return __y < __x; }
1183
1184 /// Based on operator<
1185 template<typename _Key, typename _Tp, typename _Compare, typename _Alloc>
1186 inline bool
1187 operator<=(const multimap<_Key, _Tp, _Compare, _Alloc>& __x,
1188 const multimap<_Key, _Tp, _Compare, _Alloc>& __y)
1189 { return !(__y < __x); }
1190
1191 /// Based on operator<
1192 template<typename _Key, typename _Tp, typename _Compare, typename _Alloc>
1193 inline bool
1194 operator>=(const multimap<_Key, _Tp, _Compare, _Alloc>& __x,
1195 const multimap<_Key, _Tp, _Compare, _Alloc>& __y)
1196 { return !(__x < __y); }
1197 #endif // three-way comparison
1198
1199 /// See std::multimap::swap().
1200 template<typename _Key, typename _Tp, typename _Compare, typename _Alloc>
1201 inline void
1202 swap(multimap<_Key, _Tp, _Compare, _Alloc>& __x,
1203 multimap<_Key, _Tp, _Compare, _Alloc>& __y)
1204 _GLIBCXX_NOEXCEPT_IF(noexcept(__x.swap(__y)))
1205 { __x.swap(__y); }
1206
1207 _GLIBCXX_END_NAMESPACE_CONTAINER
1208
1209 #if __cplusplus > 201402L
1210 // Allow std::multimap access to internals of compatible maps.
1211 template<typename _Key, typename _Val, typename _Cmp1, typename _Alloc,
1212 typename _Cmp2>
1213 struct
1214 _Rb_tree_merge_helper<_GLIBCXX_STD_C::multimap<_Key, _Val, _Cmp1, _Alloc>,
1215 _Cmp2>
1216 {
1217 private:
1218 friend class _GLIBCXX_STD_C::multimap<_Key, _Val, _Cmp1, _Alloc>;
1219
1220 static auto&
1221 _S_get_tree(_GLIBCXX_STD_C::map<_Key, _Val, _Cmp2, _Alloc>& __map)
1222 { return __map._M_t; }
1223
1224 static auto&
1225 _S_get_tree(_GLIBCXX_STD_C::multimap<_Key, _Val, _Cmp2, _Alloc>& __map)
1226 { return __map._M_t; }
1227 };
1228 #endif // C++17
1229
1230 _GLIBCXX_END_NAMESPACE_VERSION
1231 } // namespace std
1232
1233 #endif /* _STL_MULTIMAP_H */
1234