1 // Multimap implementation -*- C++ -*-
2 
3 // Copyright (C) 2001-2018 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 
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 && defined(__STRICT_ANSI__)
121       static_assert(is_same<typename _Alloc::value_type, value_type>::value,
122 	  "std::multimap must have the same value_type as its allocator");
123 #endif
124 
125     public:
126       class value_compare
127       : public std::binary_function<value_type, value_type, bool>
128       {
129 	friend class multimap<_Key, _Tp, _Compare, _Alloc>;
130       protected:
131 	_Compare comp;
132 
133 	value_compare(_Compare __c)
134 	: comp(__c) { }
135 
136       public:
137 	bool operator()(const value_type& __x, const value_type& __y) const
138 	{ return comp(__x.first, __y.first); }
139       };
140 
141     private:
142       /// This turns a red-black tree into a [multi]map.
143       typedef typename __gnu_cxx::__alloc_traits<_Alloc>::template
144 	rebind<value_type>::other _Pair_alloc_type;
145 
146       typedef _Rb_tree<key_type, value_type, _Select1st<value_type>,
147 		       key_compare, _Pair_alloc_type> _Rep_type;
148       /// The actual tree structure.
149       _Rep_type _M_t;
150 
151       typedef __gnu_cxx::__alloc_traits<_Pair_alloc_type> _Alloc_traits;
152 
153     public:
154       // many of these are specified differently in ISO, but the following are
155       // "functionally equivalent"
156       typedef typename _Alloc_traits::pointer		 pointer;
157       typedef typename _Alloc_traits::const_pointer	 const_pointer;
158       typedef typename _Alloc_traits::reference		 reference;
159       typedef typename _Alloc_traits::const_reference	 const_reference;
160       typedef typename _Rep_type::iterator		 iterator;
161       typedef typename _Rep_type::const_iterator	 const_iterator;
162       typedef typename _Rep_type::size_type		 size_type;
163       typedef typename _Rep_type::difference_type	 difference_type;
164       typedef typename _Rep_type::reverse_iterator	 reverse_iterator;
165       typedef typename _Rep_type::const_reverse_iterator const_reverse_iterator;
166 
167 #if __cplusplus > 201402L
168       using node_type = typename _Rep_type::node_type;
169 #endif
170 
171       // [23.3.2] construct/copy/destroy
172       // (get_allocator() is also listed in this section)
173 
174       /**
175        *  @brief  Default constructor creates no elements.
176        */
177 #if __cplusplus < 201103L
178       multimap() : _M_t() { }
179 #else
180       multimap() = default;
181 #endif
182 
183       /**
184        *  @brief  Creates a %multimap with no elements.
185        *  @param  __comp  A comparison object.
186        *  @param  __a  An allocator object.
187        */
188       explicit
189       multimap(const _Compare& __comp,
190 	       const allocator_type& __a = allocator_type())
191       : _M_t(__comp, _Pair_alloc_type(__a)) { }
192 
193       /**
194        *  @brief  %Multimap copy constructor.
195        *
196        *  Whether the allocator is copied depends on the allocator traits.
197        */
198 #if __cplusplus < 201103L
199       multimap(const multimap& __x)
200       : _M_t(__x._M_t) { }
201 #else
202       multimap(const multimap&) = default;
203 
204       /**
205        *  @brief  %Multimap move constructor.
206        *
207        *  The newly-created %multimap contains the exact contents of the
208        *  moved instance. The moved instance is a valid, but unspecified
209        *  %multimap.
210        */
211       multimap(multimap&&) = default;
212 
213       /**
214        *  @brief  Builds a %multimap from an initializer_list.
215        *  @param  __l  An initializer_list.
216        *  @param  __comp  A comparison functor.
217        *  @param  __a  An allocator object.
218        *
219        *  Create a %multimap consisting of copies of the elements from
220        *  the initializer_list.  This is linear in N if the list is already
221        *  sorted, and NlogN otherwise (where N is @a __l.size()).
222        */
223       multimap(initializer_list<value_type> __l,
224 	       const _Compare& __comp = _Compare(),
225 	       const allocator_type& __a = allocator_type())
226       : _M_t(__comp, _Pair_alloc_type(__a))
227       { _M_t._M_insert_equal(__l.begin(), __l.end()); }
228 
229       /// Allocator-extended default constructor.
230       explicit
231       multimap(const allocator_type& __a)
232       : _M_t(_Compare(), _Pair_alloc_type(__a)) { }
233 
234       /// Allocator-extended copy constructor.
235       multimap(const multimap& __m, const allocator_type& __a)
236       : _M_t(__m._M_t, _Pair_alloc_type(__a)) { }
237 
238       /// Allocator-extended move constructor.
239       multimap(multimap&& __m, const allocator_type& __a)
240       noexcept(is_nothrow_copy_constructible<_Compare>::value
241 	       && _Alloc_traits::_S_always_equal())
242       : _M_t(std::move(__m._M_t), _Pair_alloc_type(__a)) { }
243 
244       /// Allocator-extended initialier-list constructor.
245       multimap(initializer_list<value_type> __l, const allocator_type& __a)
246       : _M_t(_Compare(), _Pair_alloc_type(__a))
247       { _M_t._M_insert_equal(__l.begin(), __l.end()); }
248 
249       /// Allocator-extended range constructor.
250       template<typename _InputIterator>
251 	multimap(_InputIterator __first, _InputIterator __last,
252 		 const allocator_type& __a)
253 	: _M_t(_Compare(), _Pair_alloc_type(__a))
254 	{ _M_t._M_insert_equal(__first, __last); }
255 #endif
256 
257       /**
258        *  @brief  Builds a %multimap from a range.
259        *  @param  __first  An input iterator.
260        *  @param  __last  An input iterator.
261        *
262        *  Create a %multimap consisting of copies of the elements from
263        *  [__first,__last).  This is linear in N if the range is already sorted,
264        *  and NlogN otherwise (where N is distance(__first,__last)).
265        */
266       template<typename _InputIterator>
267 	multimap(_InputIterator __first, _InputIterator __last)
268 	: _M_t()
269 	{ _M_t._M_insert_equal(__first, __last); }
270 
271       /**
272        *  @brief  Builds a %multimap from a range.
273        *  @param  __first  An input iterator.
274        *  @param  __last  An input iterator.
275        *  @param  __comp  A comparison functor.
276        *  @param  __a  An allocator object.
277        *
278        *  Create a %multimap consisting of copies of the elements from
279        *  [__first,__last).  This is linear in N if the range is already sorted,
280        *  and NlogN otherwise (where N is distance(__first,__last)).
281        */
282       template<typename _InputIterator>
283 	multimap(_InputIterator __first, _InputIterator __last,
284 		 const _Compare& __comp,
285 		 const allocator_type& __a = allocator_type())
286 	: _M_t(__comp, _Pair_alloc_type(__a))
287 	{ _M_t._M_insert_equal(__first, __last); }
288 
289 #if __cplusplus >= 201103L
290       /**
291        *  The dtor only erases the elements, and note that if the elements
292        *  themselves are pointers, the pointed-to memory is not touched in any
293        *  way. Managing the pointer is the user's responsibility.
294        */
295       ~multimap() = default;
296 #endif
297 
298       /**
299        *  @brief  %Multimap assignment operator.
300        *
301        *  Whether the allocator is copied depends on the allocator traits.
302        */
303 #if __cplusplus < 201103L
304       multimap&
305       operator=(const multimap& __x)
306       {
307 	_M_t = __x._M_t;
308 	return *this;
309       }
310 #else
311       multimap&
312       operator=(const multimap&) = default;
313 
314       /// Move assignment operator.
315       multimap&
316       operator=(multimap&&) = default;
317 
318       /**
319        *  @brief  %Multimap list assignment operator.
320        *  @param  __l  An initializer_list.
321        *
322        *  This function fills a %multimap with copies of the elements
323        *  in the initializer list @a __l.
324        *
325        *  Note that the assignment completely changes the %multimap and
326        *  that the resulting %multimap's size is the same as the number
327        *  of elements assigned.
328        */
329       multimap&
330       operator=(initializer_list<value_type> __l)
331       {
332 	_M_t._M_assign_equal(__l.begin(), __l.end());
333 	return *this;
334       }
335 #endif
336 
337       /// Get a copy of the memory allocation object.
338       allocator_type
339       get_allocator() const _GLIBCXX_NOEXCEPT
340       { return allocator_type(_M_t.get_allocator()); }
341 
342       // iterators
343       /**
344        *  Returns a read/write iterator that points to the first pair in the
345        *  %multimap.  Iteration is done in ascending order according to the
346        *  keys.
347        */
348       iterator
349       begin() _GLIBCXX_NOEXCEPT
350       { return _M_t.begin(); }
351 
352       /**
353        *  Returns a read-only (constant) iterator that points to the first pair
354        *  in the %multimap.  Iteration is done in ascending order according to
355        *  the keys.
356        */
357       const_iterator
358       begin() const _GLIBCXX_NOEXCEPT
359       { return _M_t.begin(); }
360 
361       /**
362        *  Returns a read/write iterator that points one past the last pair in
363        *  the %multimap.  Iteration is done in ascending order according to the
364        *  keys.
365        */
366       iterator
367       end() _GLIBCXX_NOEXCEPT
368       { return _M_t.end(); }
369 
370       /**
371        *  Returns a read-only (constant) iterator that points one past the last
372        *  pair in the %multimap.  Iteration is done in ascending order according
373        *  to the keys.
374        */
375       const_iterator
376       end() const _GLIBCXX_NOEXCEPT
377       { return _M_t.end(); }
378 
379       /**
380        *  Returns a read/write reverse iterator that points to the last pair in
381        *  the %multimap.  Iteration is done in descending order according to the
382        *  keys.
383        */
384       reverse_iterator
385       rbegin() _GLIBCXX_NOEXCEPT
386       { return _M_t.rbegin(); }
387 
388       /**
389        *  Returns a read-only (constant) reverse iterator that points to the
390        *  last pair in the %multimap.  Iteration is done in descending order
391        *  according to the keys.
392        */
393       const_reverse_iterator
394       rbegin() const _GLIBCXX_NOEXCEPT
395       { return _M_t.rbegin(); }
396 
397       /**
398        *  Returns a read/write reverse iterator that points to one before the
399        *  first pair in the %multimap.  Iteration is done in descending order
400        *  according to the keys.
401        */
402       reverse_iterator
403       rend() _GLIBCXX_NOEXCEPT
404       { return _M_t.rend(); }
405 
406       /**
407        *  Returns a read-only (constant) reverse iterator that points to one
408        *  before the first pair in the %multimap.  Iteration is done in
409        *  descending order according to the keys.
410        */
411       const_reverse_iterator
412       rend() const _GLIBCXX_NOEXCEPT
413       { return _M_t.rend(); }
414 
415 #if __cplusplus >= 201103L
416       /**
417        *  Returns a read-only (constant) iterator that points to the first pair
418        *  in the %multimap.  Iteration is done in ascending order according to
419        *  the keys.
420        */
421       const_iterator
422       cbegin() const noexcept
423       { return _M_t.begin(); }
424 
425       /**
426        *  Returns a read-only (constant) iterator that points one past the last
427        *  pair in the %multimap.  Iteration is done in ascending order according
428        *  to the keys.
429        */
430       const_iterator
431       cend() const noexcept
432       { return _M_t.end(); }
433 
434       /**
435        *  Returns a read-only (constant) reverse iterator that points to the
436        *  last pair in the %multimap.  Iteration is done in descending order
437        *  according to the keys.
438        */
439       const_reverse_iterator
440       crbegin() const noexcept
441       { return _M_t.rbegin(); }
442 
443       /**
444        *  Returns a read-only (constant) reverse iterator that points to one
445        *  before the first pair in the %multimap.  Iteration is done in
446        *  descending order according to the keys.
447        */
448       const_reverse_iterator
449       crend() const noexcept
450       { return _M_t.rend(); }
451 #endif
452 
453       // capacity
454       /** Returns true if the %multimap is empty.  */
455       bool
456       empty() const _GLIBCXX_NOEXCEPT
457       { return _M_t.empty(); }
458 
459       /** Returns the size of the %multimap.  */
460       size_type
461       size() const _GLIBCXX_NOEXCEPT
462       { return _M_t.size(); }
463 
464       /** Returns the maximum size of the %multimap.  */
465       size_type
466       max_size() const _GLIBCXX_NOEXCEPT
467       { return _M_t.max_size(); }
468 
469       // modifiers
470 #if __cplusplus >= 201103L
471       /**
472        *  @brief Build and insert a std::pair into the %multimap.
473        *
474        *  @param __args  Arguments used to generate a new pair instance (see
475        *	        std::piecewise_contruct for passing arguments to each
476        *	        part of the pair constructor).
477        *
478        *  @return An iterator that points to the inserted (key,value) pair.
479        *
480        *  This function builds and inserts a (key, value) %pair into the
481        *  %multimap.
482        *  Contrary to a std::map the %multimap does not rely on unique keys and
483        *  thus multiple pairs with the same key can be inserted.
484        *
485        *  Insertion requires logarithmic time.
486        */
487       template<typename... _Args>
488 	iterator
489 	emplace(_Args&&... __args)
490 	{ return _M_t._M_emplace_equal(std::forward<_Args>(__args)...); }
491 
492       /**
493        *  @brief Builds and inserts a std::pair into the %multimap.
494        *
495        *  @param  __pos  An iterator that serves as a hint as to where the pair
496        *                should be inserted.
497        *  @param  __args  Arguments used to generate a new pair instance (see
498        *	         std::piecewise_contruct for passing arguments to each
499        *	         part of the pair constructor).
500        *  @return An iterator that points to the inserted (key,value) pair.
501        *
502        *  This function inserts a (key, value) pair into the %multimap.
503        *  Contrary to a std::map the %multimap does not rely on unique keys and
504        *  thus multiple pairs with the same key can be inserted.
505        *  Note that the first parameter is only a hint and can potentially
506        *  improve the performance of the insertion process.  A bad hint would
507        *  cause no gains in efficiency.
508        *
509        *  For more on @a hinting, see:
510        *  https://gcc.gnu.org/onlinedocs/libstdc++/manual/associative.html#containers.associative.insert_hints
511        *
512        *  Insertion requires logarithmic time (if the hint is not taken).
513        */
514       template<typename... _Args>
515 	iterator
516 	emplace_hint(const_iterator __pos, _Args&&... __args)
517 	{
518 	  return _M_t._M_emplace_hint_equal(__pos,
519 					    std::forward<_Args>(__args)...);
520 	}
521 #endif
522 
523       /**
524        *  @brief Inserts a std::pair into the %multimap.
525        *  @param  __x  Pair to be inserted (see std::make_pair for easy creation
526        *             of pairs).
527        *  @return An iterator that points to the inserted (key,value) pair.
528        *
529        *  This function inserts a (key, value) pair into the %multimap.
530        *  Contrary to a std::map the %multimap does not rely on unique keys and
531        *  thus multiple pairs with the same key can be inserted.
532        *
533        *  Insertion requires logarithmic time.
534        *  @{
535        */
536       iterator
537       insert(const value_type& __x)
538       { return _M_t._M_insert_equal(__x); }
539 
540 #if __cplusplus >= 201103L
541       // _GLIBCXX_RESOLVE_LIB_DEFECTS
542       // 2354. Unnecessary copying when inserting into maps with braced-init
543       iterator
544       insert(value_type&& __x)
545       { return _M_t._M_insert_equal(std::move(__x)); }
546 
547       template<typename _Pair>
548 	__enable_if_t<is_constructible<value_type, _Pair>::value, iterator>
549 	insert(_Pair&& __x)
550 	{ return _M_t._M_emplace_equal(std::forward<_Pair>(__x)); }
551 #endif
552       // @}
553 
554       /**
555        *  @brief Inserts a std::pair into the %multimap.
556        *  @param  __position  An iterator that serves as a hint as to where the
557        *                      pair should be inserted.
558        *  @param  __x  Pair to be inserted (see std::make_pair for easy creation
559        *               of pairs).
560        *  @return An iterator that points to the inserted (key,value) pair.
561        *
562        *  This function inserts a (key, value) pair into the %multimap.
563        *  Contrary to a std::map the %multimap does not rely on unique keys and
564        *  thus multiple pairs with the same key can be inserted.
565        *  Note that the first parameter is only a hint and can potentially
566        *  improve the performance of the insertion process.  A bad hint would
567        *  cause no gains in efficiency.
568        *
569        *  For more on @a hinting, see:
570        *  https://gcc.gnu.org/onlinedocs/libstdc++/manual/associative.html#containers.associative.insert_hints
571        *
572        *  Insertion requires logarithmic time (if the hint is not taken).
573        * @{
574        */
575       iterator
576 #if __cplusplus >= 201103L
577       insert(const_iterator __position, const value_type& __x)
578 #else
579       insert(iterator __position, const value_type& __x)
580 #endif
581       { return _M_t._M_insert_equal_(__position, __x); }
582 
583 #if __cplusplus >= 201103L
584       // _GLIBCXX_RESOLVE_LIB_DEFECTS
585       // 2354. Unnecessary copying when inserting into maps with braced-init
586       iterator
587       insert(const_iterator __position, value_type&& __x)
588       { return _M_t._M_insert_equal_(__position, std::move(__x)); }
589 
590       template<typename _Pair>
591 	__enable_if_t<is_constructible<value_type, _Pair&&>::value, iterator>
592 	insert(const_iterator __position, _Pair&& __x)
593 	{
594 	  return _M_t._M_emplace_hint_equal(__position,
595 					    std::forward<_Pair>(__x));
596 	}
597 #endif
598       // @}
599 
600       /**
601        *  @brief A template function that attempts to insert a range
602        *  of elements.
603        *  @param  __first  Iterator pointing to the start of the range to be
604        *                   inserted.
605        *  @param  __last  Iterator pointing to the end of the range.
606        *
607        *  Complexity similar to that of the range constructor.
608        */
609       template<typename _InputIterator>
610 	void
611 	insert(_InputIterator __first, _InputIterator __last)
612 	{ _M_t._M_insert_equal(__first, __last); }
613 
614 #if __cplusplus >= 201103L
615       /**
616        *  @brief Attempts to insert a list of std::pairs into the %multimap.
617        *  @param  __l  A std::initializer_list<value_type> of pairs to be
618        *               inserted.
619        *
620        *  Complexity similar to that of the range constructor.
621        */
622       void
623       insert(initializer_list<value_type> __l)
624       { this->insert(__l.begin(), __l.end()); }
625 #endif
626 
627 #if __cplusplus > 201402L
628       /// Extract a node.
629       node_type
630       extract(const_iterator __pos)
631       {
632 	__glibcxx_assert(__pos != end());
633 	return _M_t.extract(__pos);
634       }
635 
636       /// Extract a node.
637       node_type
638       extract(const key_type& __x)
639       { return _M_t.extract(__x); }
640 
641       /// Re-insert an extracted node.
642       iterator
643       insert(node_type&& __nh)
644       { return _M_t._M_reinsert_node_equal(std::move(__nh)); }
645 
646       /// Re-insert an extracted node.
647       iterator
648       insert(const_iterator __hint, node_type&& __nh)
649       { return _M_t._M_reinsert_node_hint_equal(__hint, std::move(__nh)); }
650 
651       template<typename, typename>
652 	friend class std::_Rb_tree_merge_helper;
653 
654       template<typename _C2>
655 	void
656 	merge(multimap<_Key, _Tp, _C2, _Alloc>& __source)
657 	{
658 	  using _Merge_helper = _Rb_tree_merge_helper<multimap, _C2>;
659 	  _M_t._M_merge_equal(_Merge_helper::_S_get_tree(__source));
660 	}
661 
662       template<typename _C2>
663 	void
664 	merge(multimap<_Key, _Tp, _C2, _Alloc>&& __source)
665 	{ merge(__source); }
666 
667       template<typename _C2>
668 	void
669 	merge(map<_Key, _Tp, _C2, _Alloc>& __source)
670 	{
671 	  using _Merge_helper = _Rb_tree_merge_helper<multimap, _C2>;
672 	  _M_t._M_merge_equal(_Merge_helper::_S_get_tree(__source));
673 	}
674 
675       template<typename _C2>
676 	void
677 	merge(map<_Key, _Tp, _C2, _Alloc>&& __source)
678 	{ merge(__source); }
679 #endif // C++17
680 
681 #if __cplusplus >= 201103L
682       // _GLIBCXX_RESOLVE_LIB_DEFECTS
683       // DR 130. Associative erase should return an iterator.
684       /**
685        *  @brief Erases an element from a %multimap.
686        *  @param  __position  An iterator pointing to the element to be erased.
687        *  @return An iterator pointing to the element immediately following
688        *          @a position prior to the element being erased. If no such
689        *          element exists, end() is returned.
690        *
691        *  This function erases an element, pointed to by the given iterator,
692        *  from a %multimap.  Note that this function only erases the element,
693        *  and that if the element is itself a pointer, the pointed-to memory is
694        *  not touched in any way.  Managing the pointer is the user's
695        *  responsibility.
696        *
697        * @{
698        */
699       iterator
700       erase(const_iterator __position)
701       { return _M_t.erase(__position); }
702 
703       // LWG 2059.
704       _GLIBCXX_ABI_TAG_CXX11
705       iterator
706       erase(iterator __position)
707       { return _M_t.erase(__position); }
708       // @}
709 #else
710       /**
711        *  @brief Erases an element from a %multimap.
712        *  @param  __position  An iterator pointing to the element to be erased.
713        *
714        *  This function erases an element, pointed to by the given iterator,
715        *  from a %multimap.  Note that this function only erases the element,
716        *  and that if the element is itself a pointer, the pointed-to memory is
717        *  not touched in any way.  Managing the pointer is the user's
718        *  responsibility.
719        */
720       void
721       erase(iterator __position)
722       { _M_t.erase(__position); }
723 #endif
724 
725       /**
726        *  @brief Erases elements according to the provided key.
727        *  @param  __x  Key of element to be erased.
728        *  @return  The number of elements erased.
729        *
730        *  This function erases all elements located by the given key from a
731        *  %multimap.
732        *  Note that this function only erases the element, and that if
733        *  the element is itself a pointer, the pointed-to memory is not touched
734        *  in any way.  Managing the pointer is the user's responsibility.
735        */
736       size_type
737       erase(const key_type& __x)
738       { return _M_t.erase(__x); }
739 
740 #if __cplusplus >= 201103L
741       // _GLIBCXX_RESOLVE_LIB_DEFECTS
742       // DR 130. Associative erase should return an iterator.
743       /**
744        *  @brief Erases a [first,last) range of elements from a %multimap.
745        *  @param  __first  Iterator pointing to the start of the range to be
746        *                   erased.
747        *  @param __last Iterator pointing to the end of the range to be
748        *                erased .
749        *  @return The iterator @a __last.
750        *
751        *  This function erases a sequence of elements from a %multimap.
752        *  Note that this function only erases the elements, and that if
753        *  the elements themselves are pointers, the pointed-to memory is not
754        *  touched in any way.  Managing the pointer is the user's
755        *  responsibility.
756        */
757       iterator
758       erase(const_iterator __first, const_iterator __last)
759       { return _M_t.erase(__first, __last); }
760 #else
761       // _GLIBCXX_RESOLVE_LIB_DEFECTS
762       // DR 130. Associative erase should return an iterator.
763       /**
764        *  @brief Erases a [first,last) range of elements from a %multimap.
765        *  @param  __first  Iterator pointing to the start of the range to be
766        *                 erased.
767        *  @param __last Iterator pointing to the end of the range to
768        *                be erased.
769        *
770        *  This function erases a sequence of elements from a %multimap.
771        *  Note that this function only erases the elements, and that if
772        *  the elements themselves are pointers, the pointed-to memory is not
773        *  touched in any way.  Managing the pointer is the user's
774        *  responsibility.
775        */
776       void
777       erase(iterator __first, iterator __last)
778       { _M_t.erase(__first, __last); }
779 #endif
780 
781       /**
782        *  @brief  Swaps data with another %multimap.
783        *  @param  __x  A %multimap of the same element and allocator types.
784        *
785        *  This exchanges the elements between two multimaps in constant time.
786        *  (It is only swapping a pointer, an integer, and an instance of
787        *  the @c Compare type (which itself is often stateless and empty), so it
788        *  should be quite fast.)
789        *  Note that the global std::swap() function is specialized such that
790        *  std::swap(m1,m2) will feed to this function.
791        *
792        *  Whether the allocators are swapped depends on the allocator traits.
793        */
794       void
795       swap(multimap& __x)
796       _GLIBCXX_NOEXCEPT_IF(__is_nothrow_swappable<_Compare>::value)
797       { _M_t.swap(__x._M_t); }
798 
799       /**
800        *  Erases all elements in a %multimap.  Note that this function only
801        *  erases the elements, and that if the elements themselves are pointers,
802        *  the pointed-to memory is not touched in any way.  Managing the pointer
803        *  is the user's responsibility.
804        */
805       void
806       clear() _GLIBCXX_NOEXCEPT
807       { _M_t.clear(); }
808 
809       // observers
810       /**
811        *  Returns the key comparison object out of which the %multimap
812        *  was constructed.
813        */
814       key_compare
815       key_comp() const
816       { return _M_t.key_comp(); }
817 
818       /**
819        *  Returns a value comparison object, built from the key comparison
820        *  object out of which the %multimap was constructed.
821        */
822       value_compare
823       value_comp() const
824       { return value_compare(_M_t.key_comp()); }
825 
826       // multimap operations
827 
828       //@{
829       /**
830        *  @brief Tries to locate an element in a %multimap.
831        *  @param  __x  Key of (key, value) pair to be located.
832        *  @return  Iterator pointing to sought-after element,
833        *           or end() if not found.
834        *
835        *  This function takes a key and tries to locate the element with which
836        *  the key matches.  If successful the function returns an iterator
837        *  pointing to the sought after %pair.  If unsuccessful it returns the
838        *  past-the-end ( @c end() ) iterator.
839        */
840       iterator
841       find(const key_type& __x)
842       { return _M_t.find(__x); }
843 
844 #if __cplusplus > 201103L
845       template<typename _Kt>
846 	auto
847 	find(const _Kt& __x) -> decltype(_M_t._M_find_tr(__x))
848 	{ return _M_t._M_find_tr(__x); }
849 #endif
850       //@}
851 
852       //@{
853       /**
854        *  @brief Tries to locate an element in a %multimap.
855        *  @param  __x  Key of (key, value) pair to be located.
856        *  @return  Read-only (constant) iterator pointing to sought-after
857        *           element, or end() if not found.
858        *
859        *  This function takes a key and tries to locate the element with which
860        *  the key matches.  If successful the function returns a constant
861        *  iterator pointing to the sought after %pair.  If unsuccessful it
862        *  returns the past-the-end ( @c end() ) iterator.
863        */
864       const_iterator
865       find(const key_type& __x) const
866       { return _M_t.find(__x); }
867 
868 #if __cplusplus > 201103L
869       template<typename _Kt>
870 	auto
871 	find(const _Kt& __x) const -> decltype(_M_t._M_find_tr(__x))
872 	{ return _M_t._M_find_tr(__x); }
873 #endif
874       //@}
875 
876       //@{
877       /**
878        *  @brief Finds the number of elements with given key.
879        *  @param  __x  Key of (key, value) pairs to be located.
880        *  @return Number of elements with specified key.
881        */
882       size_type
883       count(const key_type& __x) const
884       { return _M_t.count(__x); }
885 
886 #if __cplusplus > 201103L
887       template<typename _Kt>
888 	auto
889 	count(const _Kt& __x) const -> decltype(_M_t._M_count_tr(__x))
890 	{ return _M_t._M_count_tr(__x); }
891 #endif
892       //@}
893 
894       //@{
895       /**
896        *  @brief Finds the beginning of a subsequence matching given key.
897        *  @param  __x  Key of (key, value) pair to be located.
898        *  @return  Iterator pointing to first element equal to or greater
899        *           than key, or end().
900        *
901        *  This function returns the first element of a subsequence of elements
902        *  that matches the given key.  If unsuccessful it returns an iterator
903        *  pointing to the first element that has a greater value than given key
904        *  or end() if no such element exists.
905        */
906       iterator
907       lower_bound(const key_type& __x)
908       { return _M_t.lower_bound(__x); }
909 
910 #if __cplusplus > 201103L
911       template<typename _Kt>
912 	auto
913 	lower_bound(const _Kt& __x)
914 	-> decltype(iterator(_M_t._M_lower_bound_tr(__x)))
915 	{ return iterator(_M_t._M_lower_bound_tr(__x)); }
916 #endif
917       //@}
918 
919       //@{
920       /**
921        *  @brief Finds the beginning of a subsequence matching given key.
922        *  @param  __x  Key of (key, value) pair to be located.
923        *  @return  Read-only (constant) iterator pointing to first element
924        *           equal to or greater than key, or end().
925        *
926        *  This function returns the first element of a subsequence of
927        *  elements that matches the given key.  If unsuccessful the
928        *  iterator will point to the next greatest element or, if no
929        *  such greater element exists, to end().
930        */
931       const_iterator
932       lower_bound(const key_type& __x) const
933       { return _M_t.lower_bound(__x); }
934 
935 #if __cplusplus > 201103L
936       template<typename _Kt>
937 	auto
938 	lower_bound(const _Kt& __x) const
939 	-> decltype(const_iterator(_M_t._M_lower_bound_tr(__x)))
940 	{ return const_iterator(_M_t._M_lower_bound_tr(__x)); }
941 #endif
942       //@}
943 
944       //@{
945       /**
946        *  @brief Finds the end of a subsequence matching given key.
947        *  @param  __x  Key of (key, value) pair to be located.
948        *  @return Iterator pointing to the first element
949        *          greater than key, or end().
950        */
951       iterator
952       upper_bound(const key_type& __x)
953       { return _M_t.upper_bound(__x); }
954 
955 #if __cplusplus > 201103L
956       template<typename _Kt>
957 	auto
958 	upper_bound(const _Kt& __x)
959 	-> decltype(iterator(_M_t._M_upper_bound_tr(__x)))
960 	{ return iterator(_M_t._M_upper_bound_tr(__x)); }
961 #endif
962       //@}
963 
964       //@{
965       /**
966        *  @brief Finds the end of a subsequence matching given key.
967        *  @param  __x  Key of (key, value) pair to be located.
968        *  @return  Read-only (constant) iterator pointing to first iterator
969        *           greater than key, or end().
970        */
971       const_iterator
972       upper_bound(const key_type& __x) const
973       { return _M_t.upper_bound(__x); }
974 
975 #if __cplusplus > 201103L
976       template<typename _Kt>
977 	auto
978 	upper_bound(const _Kt& __x) const
979 	-> decltype(const_iterator(_M_t._M_upper_bound_tr(__x)))
980 	{ return const_iterator(_M_t._M_upper_bound_tr(__x)); }
981 #endif
982       //@}
983 
984       //@{
985       /**
986        *  @brief Finds a subsequence matching given key.
987        *  @param  __x  Key of (key, value) pairs to be located.
988        *  @return  Pair of iterators that possibly points to the subsequence
989        *           matching given key.
990        *
991        *  This function is equivalent to
992        *  @code
993        *    std::make_pair(c.lower_bound(val),
994        *                   c.upper_bound(val))
995        *  @endcode
996        *  (but is faster than making the calls separately).
997        */
998       std::pair<iterator, iterator>
999       equal_range(const key_type& __x)
1000       { return _M_t.equal_range(__x); }
1001 
1002 #if __cplusplus > 201103L
1003       template<typename _Kt>
1004 	auto
1005 	equal_range(const _Kt& __x)
1006 	-> decltype(pair<iterator, iterator>(_M_t._M_equal_range_tr(__x)))
1007 	{ return pair<iterator, iterator>(_M_t._M_equal_range_tr(__x)); }
1008 #endif
1009       //@}
1010 
1011       //@{
1012       /**
1013        *  @brief Finds a subsequence matching given key.
1014        *  @param  __x  Key of (key, value) pairs to be located.
1015        *  @return  Pair of read-only (constant) iterators that possibly points
1016        *           to the subsequence matching given key.
1017        *
1018        *  This function is equivalent to
1019        *  @code
1020        *    std::make_pair(c.lower_bound(val),
1021        *                   c.upper_bound(val))
1022        *  @endcode
1023        *  (but is faster than making the calls separately).
1024        */
1025       std::pair<const_iterator, const_iterator>
1026       equal_range(const key_type& __x) const
1027       { return _M_t.equal_range(__x); }
1028 
1029 #if __cplusplus > 201103L
1030       template<typename _Kt>
1031 	auto
1032 	equal_range(const _Kt& __x) const
1033 	-> decltype(pair<const_iterator, const_iterator>(
1034 	      _M_t._M_equal_range_tr(__x)))
1035 	{
1036 	  return pair<const_iterator, const_iterator>(
1037 	      _M_t._M_equal_range_tr(__x));
1038 	}
1039 #endif
1040       //@}
1041 
1042       template<typename _K1, typename _T1, typename _C1, typename _A1>
1043 	friend bool
1044 	operator==(const multimap<_K1, _T1, _C1, _A1>&,
1045 		   const multimap<_K1, _T1, _C1, _A1>&);
1046 
1047       template<typename _K1, typename _T1, typename _C1, typename _A1>
1048 	friend bool
1049 	operator<(const multimap<_K1, _T1, _C1, _A1>&,
1050 		  const multimap<_K1, _T1, _C1, _A1>&);
1051   };
1052 
1053 #if __cpp_deduction_guides >= 201606
1054 
1055   template<typename _InputIterator,
1056 	   typename _Compare = less<__iter_key_t<_InputIterator>>,
1057 	   typename _Allocator = allocator<__iter_to_alloc_t<_InputIterator>>,
1058 	   typename = _RequireInputIter<_InputIterator>,
1059 	   typename = _RequireAllocator<_Allocator>>
1060     multimap(_InputIterator, _InputIterator,
1061 	     _Compare = _Compare(), _Allocator = _Allocator())
1062     -> multimap<__iter_key_t<_InputIterator>, __iter_val_t<_InputIterator>,
1063 		_Compare, _Allocator>;
1064 
1065   template<typename _Key, typename _Tp, typename _Compare = less<_Key>,
1066 	   typename _Allocator = allocator<pair<const _Key, _Tp>>,
1067 	   typename = _RequireAllocator<_Allocator>>
1068     multimap(initializer_list<pair<_Key, _Tp>>,
1069 	     _Compare = _Compare(), _Allocator = _Allocator())
1070     -> multimap<_Key, _Tp, _Compare, _Allocator>;
1071 
1072   template<typename _InputIterator, typename _Allocator,
1073 	   typename = _RequireInputIter<_InputIterator>,
1074 	   typename = _RequireAllocator<_Allocator>>
1075     multimap(_InputIterator, _InputIterator, _Allocator)
1076     -> multimap<__iter_key_t<_InputIterator>, __iter_val_t<_InputIterator>,
1077 		less<__iter_key_t<_InputIterator>>, _Allocator>;
1078 
1079   template<typename _Key, typename _Tp, typename _Allocator,
1080 	   typename = _RequireAllocator<_Allocator>>
1081     multimap(initializer_list<pair<_Key, _Tp>>, _Allocator)
1082     -> multimap<_Key, _Tp, less<_Key>, _Allocator>;
1083 
1084 #endif
1085 
1086   /**
1087    *  @brief  Multimap equality comparison.
1088    *  @param  __x  A %multimap.
1089    *  @param  __y  A %multimap of the same type as @a __x.
1090    *  @return  True iff the size and elements of the maps are equal.
1091    *
1092    *  This is an equivalence relation.  It is linear in the size of the
1093    *  multimaps.  Multimaps are considered equivalent if their sizes are equal,
1094    *  and if corresponding elements compare equal.
1095   */
1096   template<typename _Key, typename _Tp, typename _Compare, typename _Alloc>
1097     inline bool
1098     operator==(const multimap<_Key, _Tp, _Compare, _Alloc>& __x,
1099 	       const multimap<_Key, _Tp, _Compare, _Alloc>& __y)
1100     { return __x._M_t == __y._M_t; }
1101 
1102   /**
1103    *  @brief  Multimap ordering relation.
1104    *  @param  __x  A %multimap.
1105    *  @param  __y  A %multimap of the same type as @a __x.
1106    *  @return  True iff @a x is lexicographically less than @a y.
1107    *
1108    *  This is a total ordering relation.  It is linear in the size of the
1109    *  multimaps.  The elements must be comparable with @c <.
1110    *
1111    *  See std::lexicographical_compare() for how the determination is made.
1112   */
1113   template<typename _Key, typename _Tp, typename _Compare, typename _Alloc>
1114     inline bool
1115     operator<(const multimap<_Key, _Tp, _Compare, _Alloc>& __x,
1116 	      const multimap<_Key, _Tp, _Compare, _Alloc>& __y)
1117     { return __x._M_t < __y._M_t; }
1118 
1119   /// Based on operator==
1120   template<typename _Key, typename _Tp, typename _Compare, typename _Alloc>
1121     inline bool
1122     operator!=(const multimap<_Key, _Tp, _Compare, _Alloc>& __x,
1123 	       const multimap<_Key, _Tp, _Compare, _Alloc>& __y)
1124     { return !(__x == __y); }
1125 
1126   /// Based on operator<
1127   template<typename _Key, typename _Tp, typename _Compare, typename _Alloc>
1128     inline bool
1129     operator>(const multimap<_Key, _Tp, _Compare, _Alloc>& __x,
1130 	      const multimap<_Key, _Tp, _Compare, _Alloc>& __y)
1131     { return __y < __x; }
1132 
1133   /// Based on operator<
1134   template<typename _Key, typename _Tp, typename _Compare, typename _Alloc>
1135     inline bool
1136     operator<=(const multimap<_Key, _Tp, _Compare, _Alloc>& __x,
1137 	       const multimap<_Key, _Tp, _Compare, _Alloc>& __y)
1138     { return !(__y < __x); }
1139 
1140   /// Based on operator<
1141   template<typename _Key, typename _Tp, typename _Compare, typename _Alloc>
1142     inline bool
1143     operator>=(const multimap<_Key, _Tp, _Compare, _Alloc>& __x,
1144 	       const multimap<_Key, _Tp, _Compare, _Alloc>& __y)
1145     { return !(__x < __y); }
1146 
1147   /// See std::multimap::swap().
1148   template<typename _Key, typename _Tp, typename _Compare, typename _Alloc>
1149     inline void
1150     swap(multimap<_Key, _Tp, _Compare, _Alloc>& __x,
1151 	 multimap<_Key, _Tp, _Compare, _Alloc>& __y)
1152     _GLIBCXX_NOEXCEPT_IF(noexcept(__x.swap(__y)))
1153     { __x.swap(__y); }
1154 
1155 _GLIBCXX_END_NAMESPACE_CONTAINER
1156 
1157 #if __cplusplus > 201402L
1158   // Allow std::multimap access to internals of compatible maps.
1159   template<typename _Key, typename _Val, typename _Cmp1, typename _Alloc,
1160 	   typename _Cmp2>
1161     struct
1162     _Rb_tree_merge_helper<_GLIBCXX_STD_C::multimap<_Key, _Val, _Cmp1, _Alloc>,
1163 			  _Cmp2>
1164     {
1165     private:
1166       friend class _GLIBCXX_STD_C::multimap<_Key, _Val, _Cmp1, _Alloc>;
1167 
1168       static auto&
1169       _S_get_tree(_GLIBCXX_STD_C::map<_Key, _Val, _Cmp2, _Alloc>& __map)
1170       { return __map._M_t; }
1171 
1172       static auto&
1173       _S_get_tree(_GLIBCXX_STD_C::multimap<_Key, _Val, _Cmp2, _Alloc>& __map)
1174       { return __map._M_t; }
1175     };
1176 #endif // C++17
1177 
1178 _GLIBCXX_END_NAMESPACE_VERSION
1179 } // namespace std
1180 
1181 #endif /* _STL_MULTIMAP_H */
1182