xref: /netbsd-src/external/gpl3/gcc.old/dist/libstdc++-v3/include/bits/stl_multiset.h (revision 946379e7b37692fc43f68eb0d1c10daa0a7f3b6c)
1 // Multiset implementation -*- C++ -*-
2 
3 // Copyright (C) 2001-2013 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 
64 namespace std _GLIBCXX_VISIBILITY(default)
65 {
66 _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
67 
68   /**
69    *  @brief A standard container made up of elements, which can be retrieved
70    *  in logarithmic time.
71    *
72    *  @ingroup associative_containers
73    *
74    *
75    *  @tparam _Key  Type of key objects.
76    *  @tparam _Compare  Comparison function object type, defaults to less<_Key>.
77    *  @tparam _Alloc  Allocator type, defaults to allocator<_Key>.
78    *
79    *  Meets the requirements of a <a href="tables.html#65">container</a>, a
80    *  <a href="tables.html#66">reversible container</a>, and an
81    *  <a href="tables.html#69">associative container</a> (using equivalent
82    *  keys).  For a @c multiset<Key> the key_type and value_type are Key.
83    *
84    *  Multisets support bidirectional iterators.
85    *
86    *  The private tree data is declared exactly the same way for set and
87    *  multiset; the distinction is made entirely in how the tree functions are
88    *  called (*_unique versus *_equal, same as the standard).
89   */
90   template <typename _Key, typename _Compare = std::less<_Key>,
91 	    typename _Alloc = std::allocator<_Key> >
92     class multiset
93     {
94       // concept requirements
95       typedef typename _Alloc::value_type                   _Alloc_value_type;
96       __glibcxx_class_requires(_Key, _SGIAssignableConcept)
97       __glibcxx_class_requires4(_Compare, bool, _Key, _Key,
98 				_BinaryFunctionConcept)
99       __glibcxx_class_requires2(_Key, _Alloc_value_type, _SameTypeConcept)
100 
101     public:
102       // typedefs:
103       typedef _Key     key_type;
104       typedef _Key     value_type;
105       typedef _Compare key_compare;
106       typedef _Compare value_compare;
107       typedef _Alloc   allocator_type;
108 
109     private:
110       /// This turns a red-black tree into a [multi]set.
111       typedef typename _Alloc::template rebind<_Key>::other _Key_alloc_type;
112 
113       typedef _Rb_tree<key_type, value_type, _Identity<value_type>,
114 		       key_compare, _Key_alloc_type> _Rep_type;
115       /// The actual tree structure.
116       _Rep_type _M_t;
117 
118     public:
119       typedef typename _Key_alloc_type::pointer             pointer;
120       typedef typename _Key_alloc_type::const_pointer       const_pointer;
121       typedef typename _Key_alloc_type::reference           reference;
122       typedef typename _Key_alloc_type::const_reference     const_reference;
123       // _GLIBCXX_RESOLVE_LIB_DEFECTS
124       // DR 103. set::iterator is required to be modifiable,
125       // but this allows modification of keys.
126       typedef typename _Rep_type::const_iterator            iterator;
127       typedef typename _Rep_type::const_iterator            const_iterator;
128       typedef typename _Rep_type::const_reverse_iterator    reverse_iterator;
129       typedef typename _Rep_type::const_reverse_iterator const_reverse_iterator;
130       typedef typename _Rep_type::size_type                 size_type;
131       typedef typename _Rep_type::difference_type           difference_type;
132 
133       // allocation/deallocation
134       /**
135        *  @brief  Default constructor creates no elements.
136        */
137       multiset()
138       : _M_t() { }
139 
140       /**
141        *  @brief  Creates a %multiset with no elements.
142        *  @param  __comp  Comparator to use.
143        *  @param  __a  An allocator object.
144        */
145       explicit
146       multiset(const _Compare& __comp,
147 	       const allocator_type& __a = allocator_type())
148       : _M_t(__comp, _Key_alloc_type(__a)) { }
149 
150       /**
151        *  @brief  Builds a %multiset from a range.
152        *  @param  __first  An input iterator.
153        *  @param  __last  An input iterator.
154        *
155        *  Create a %multiset consisting of copies of the elements from
156        *  [first,last).  This is linear in N if the range is already sorted,
157        *  and NlogN otherwise (where N is distance(__first,__last)).
158        */
159       template<typename _InputIterator>
160         multiset(_InputIterator __first, _InputIterator __last)
161 	: _M_t()
162         { _M_t._M_insert_equal(__first, __last); }
163 
164       /**
165        *  @brief  Builds a %multiset from a range.
166        *  @param  __first  An input iterator.
167        *  @param  __last  An input iterator.
168        *  @param  __comp  A comparison functor.
169        *  @param  __a  An allocator object.
170        *
171        *  Create a %multiset consisting of copies of the elements from
172        *  [__first,__last).  This is linear in N if the range is already sorted,
173        *  and NlogN otherwise (where N is distance(__first,__last)).
174        */
175       template<typename _InputIterator>
176         multiset(_InputIterator __first, _InputIterator __last,
177 		 const _Compare& __comp,
178 		 const allocator_type& __a = allocator_type())
179 	: _M_t(__comp, _Key_alloc_type(__a))
180         { _M_t._M_insert_equal(__first, __last); }
181 
182       /**
183        *  @brief  %Multiset copy constructor.
184        *  @param  __x  A %multiset of identical element and allocator types.
185        *
186        *  The newly-created %multiset uses a copy of the allocation object used
187        *  by @a __x.
188        */
189       multiset(const multiset& __x)
190       : _M_t(__x._M_t) { }
191 
192 #if __cplusplus >= 201103L
193      /**
194        *  @brief  %Multiset move constructor.
195        *  @param  __x  A %multiset of identical element and allocator types.
196        *
197        *  The newly-created %multiset contains the exact contents of @a __x.
198        *  The contents of @a __x are a valid, but unspecified %multiset.
199        */
200       multiset(multiset&& __x)
201       noexcept(is_nothrow_copy_constructible<_Compare>::value)
202       : _M_t(std::move(__x._M_t)) { }
203 
204       /**
205        *  @brief  Builds a %multiset from an initializer_list.
206        *  @param  __l  An initializer_list.
207        *  @param  __comp  A comparison functor.
208        *  @param  __a  An allocator object.
209        *
210        *  Create a %multiset consisting of copies of the elements from
211        *  the list.  This is linear in N if the list is already sorted,
212        *  and NlogN otherwise (where N is @a __l.size()).
213        */
214       multiset(initializer_list<value_type> __l,
215 	       const _Compare& __comp = _Compare(),
216 	       const allocator_type& __a = allocator_type())
217       : _M_t(__comp, _Key_alloc_type(__a))
218       { _M_t._M_insert_equal(__l.begin(), __l.end()); }
219 #endif
220 
221       /**
222        *  @brief  %Multiset assignment operator.
223        *  @param  __x  A %multiset of identical element and allocator types.
224        *
225        *  All the elements of @a __x are copied, but unlike the copy
226        *  constructor, the allocator object is not copied.
227        */
228       multiset&
229       operator=(const multiset& __x)
230       {
231 	_M_t = __x._M_t;
232 	return *this;
233       }
234 
235 #if __cplusplus >= 201103L
236       /**
237        *  @brief  %Multiset move assignment operator.
238        *  @param  __x  A %multiset of identical element and allocator types.
239        *
240        *  The contents of @a __x are moved into this %multiset
241        *  (without copying).  @a __x is a valid, but unspecified
242        *  %multiset.
243        */
244       multiset&
245       operator=(multiset&& __x)
246       {
247 	// NB: DR 1204.
248 	// NB: DR 675.
249 	this->clear();
250 	this->swap(__x);
251 	return *this;
252       }
253 
254       /**
255        *  @brief  %Multiset list assignment operator.
256        *  @param  __l  An initializer_list.
257        *
258        *  This function fills a %multiset with copies of the elements in the
259        *  initializer list @a __l.
260        *
261        *  Note that the assignment completely changes the %multiset and
262        *  that the resulting %multiset's size is the same as the number
263        *  of elements assigned.  Old data may be lost.
264        */
265       multiset&
266       operator=(initializer_list<value_type> __l)
267       {
268 	this->clear();
269 	this->insert(__l.begin(), __l.end());
270 	return *this;
271       }
272 #endif
273 
274       // accessors:
275 
276       ///  Returns the comparison object.
277       key_compare
278       key_comp() const
279       { return _M_t.key_comp(); }
280       ///  Returns the comparison object.
281       value_compare
282       value_comp() const
283       { return _M_t.key_comp(); }
284       ///  Returns the memory allocation object.
285       allocator_type
286       get_allocator() const _GLIBCXX_NOEXCEPT
287       { return allocator_type(_M_t.get_allocator()); }
288 
289       /**
290        *  Returns a read-only (constant) iterator that points to the first
291        *  element in the %multiset.  Iteration is done in ascending order
292        *  according to the keys.
293        */
294       iterator
295       begin() const _GLIBCXX_NOEXCEPT
296       { return _M_t.begin(); }
297 
298       /**
299        *  Returns a read-only (constant) iterator that points one past the last
300        *  element in the %multiset.  Iteration is done in ascending order
301        *  according to the keys.
302        */
303       iterator
304       end() const _GLIBCXX_NOEXCEPT
305       { return _M_t.end(); }
306 
307       /**
308        *  Returns a read-only (constant) reverse iterator that points to the
309        *  last element in the %multiset.  Iteration is done in descending order
310        *  according to the keys.
311        */
312       reverse_iterator
313       rbegin() const _GLIBCXX_NOEXCEPT
314       { return _M_t.rbegin(); }
315 
316       /**
317        *  Returns a read-only (constant) reverse iterator that points to the
318        *  last element in the %multiset.  Iteration is done in descending order
319        *  according to the keys.
320        */
321       reverse_iterator
322       rend() const _GLIBCXX_NOEXCEPT
323       { return _M_t.rend(); }
324 
325 #if __cplusplus >= 201103L
326       /**
327        *  Returns a read-only (constant) iterator that points to the first
328        *  element in the %multiset.  Iteration is done in ascending order
329        *  according to the keys.
330        */
331       iterator
332       cbegin() const noexcept
333       { return _M_t.begin(); }
334 
335       /**
336        *  Returns a read-only (constant) iterator that points one past the last
337        *  element in the %multiset.  Iteration is done in ascending order
338        *  according to the keys.
339        */
340       iterator
341       cend() const noexcept
342       { return _M_t.end(); }
343 
344       /**
345        *  Returns a read-only (constant) reverse iterator that points to the
346        *  last element in the %multiset.  Iteration is done in descending order
347        *  according to the keys.
348        */
349       reverse_iterator
350       crbegin() const noexcept
351       { return _M_t.rbegin(); }
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       crend() const noexcept
360       { return _M_t.rend(); }
361 #endif
362 
363       ///  Returns true if the %set is empty.
364       bool
365       empty() const _GLIBCXX_NOEXCEPT
366       { return _M_t.empty(); }
367 
368       ///  Returns the size of the %set.
369       size_type
370       size() const _GLIBCXX_NOEXCEPT
371       { return _M_t.size(); }
372 
373       ///  Returns the maximum size of the %set.
374       size_type
375       max_size() const _GLIBCXX_NOEXCEPT
376       { return _M_t.max_size(); }
377 
378       /**
379        *  @brief  Swaps data with another %multiset.
380        *  @param  __x  A %multiset of the same element and allocator types.
381        *
382        *  This exchanges the elements between two multisets in constant time.
383        *  (It is only swapping a pointer, an integer, and an instance of the @c
384        *  Compare type (which itself is often stateless and empty), so it should
385        *  be quite fast.)
386        *  Note that the global std::swap() function is specialized such that
387        *  std::swap(s1,s2) will feed to this function.
388        */
389       void
390       swap(multiset& __x)
391       { _M_t.swap(__x._M_t); }
392 
393       // insert/erase
394 #if __cplusplus >= 201103L
395       /**
396        *  @brief Builds and inserts an element into the %multiset.
397        *  @param  __args  Arguments used to generate the element instance to be
398        *                 inserted.
399        *  @return An iterator that points to the inserted element.
400        *
401        *  This function inserts an element into the %multiset.  Contrary
402        *  to a std::set the %multiset does not rely on unique keys and thus
403        *  multiple copies of the same element can be inserted.
404        *
405        *  Insertion requires logarithmic time.
406        */
407       template<typename... _Args>
408 	iterator
409 	emplace(_Args&&... __args)
410 	{ return _M_t._M_emplace_equal(std::forward<_Args>(__args)...); }
411 
412       /**
413        *  @brief Builds and inserts an element into the %multiset.
414        *  @param  __pos  An iterator that serves as a hint as to where the
415        *                element should be inserted.
416        *  @param  __args  Arguments used to generate the element instance to be
417        *                 inserted.
418        *  @return An iterator that points to the inserted element.
419        *
420        *  This function inserts an element into the %multiset.  Contrary
421        *  to a std::set the %multiset does not rely on unique keys and thus
422        *  multiple copies of the same element can be inserted.
423        *
424        *  Note that the first parameter is only a hint and can potentially
425        *  improve the performance of the insertion process.  A bad hint would
426        *  cause no gains in efficiency.
427        *
428        *  See http://gcc.gnu.org/onlinedocs/libstdc++/manual/bk01pt07ch17.html
429        *  for more on @a hinting.
430        *
431        *  Insertion requires logarithmic time (if the hint is not taken).
432        */
433       template<typename... _Args>
434 	iterator
435 	emplace_hint(const_iterator __pos, _Args&&... __args)
436 	{
437 	  return _M_t._M_emplace_hint_equal(__pos,
438 					    std::forward<_Args>(__args)...);
439 	}
440 #endif
441 
442       /**
443        *  @brief Inserts an element into the %multiset.
444        *  @param  __x  Element to be inserted.
445        *  @return An iterator that points to the inserted element.
446        *
447        *  This function inserts an element into the %multiset.  Contrary
448        *  to a std::set the %multiset does not rely on unique keys and thus
449        *  multiple copies of the same element can be inserted.
450        *
451        *  Insertion requires logarithmic time.
452        */
453       iterator
454       insert(const value_type& __x)
455       { return _M_t._M_insert_equal(__x); }
456 
457 #if __cplusplus >= 201103L
458       iterator
459       insert(value_type&& __x)
460       { return _M_t._M_insert_equal(std::move(__x)); }
461 #endif
462 
463       /**
464        *  @brief Inserts an element into the %multiset.
465        *  @param  __position  An iterator that serves as a hint as to where the
466        *                    element should be inserted.
467        *  @param  __x  Element to be inserted.
468        *  @return An iterator that points to the inserted element.
469        *
470        *  This function inserts an element into the %multiset.  Contrary
471        *  to a std::set the %multiset does not rely on unique keys and thus
472        *  multiple copies of the same element can be inserted.
473        *
474        *  Note that the first parameter is only a hint and can potentially
475        *  improve the performance of the insertion process.  A bad hint would
476        *  cause no gains in efficiency.
477        *
478        *  See http://gcc.gnu.org/onlinedocs/libstdc++/manual/bk01pt07ch17.html
479        *  for more on @a hinting.
480        *
481        *  Insertion requires logarithmic time (if the hint is not taken).
482        */
483       iterator
484       insert(const_iterator __position, const value_type& __x)
485       { return _M_t._M_insert_equal_(__position, __x); }
486 
487 #if __cplusplus >= 201103L
488       iterator
489       insert(const_iterator __position, value_type&& __x)
490       { return _M_t._M_insert_equal_(__position, std::move(__x)); }
491 #endif
492 
493       /**
494        *  @brief A template function that tries to insert a range of elements.
495        *  @param  __first  Iterator pointing to the start of the range to be
496        *                   inserted.
497        *  @param  __last  Iterator pointing to the end of the range.
498        *
499        *  Complexity similar to that of the range constructor.
500        */
501       template<typename _InputIterator>
502         void
503         insert(_InputIterator __first, _InputIterator __last)
504         { _M_t._M_insert_equal(__first, __last); }
505 
506 #if __cplusplus >= 201103L
507       /**
508        *  @brief Attempts to insert a list of elements into the %multiset.
509        *  @param  __l  A std::initializer_list<value_type> of elements
510        *               to be inserted.
511        *
512        *  Complexity similar to that of the range constructor.
513        */
514       void
515       insert(initializer_list<value_type> __l)
516       { this->insert(__l.begin(), __l.end()); }
517 #endif
518 
519 #if __cplusplus >= 201103L
520       // _GLIBCXX_RESOLVE_LIB_DEFECTS
521       // DR 130. Associative erase should return an iterator.
522       /**
523        *  @brief Erases an element from a %multiset.
524        *  @param  __position  An iterator pointing to the element to be erased.
525        *  @return An iterator pointing to the element immediately following
526        *          @a position prior to the element being erased. If no such
527        *          element exists, end() is returned.
528        *
529        *  This function erases an element, pointed to by the given iterator,
530        *  from a %multiset.  Note that this function only erases the element,
531        *  and that if the element is itself a pointer, the pointed-to memory is
532        *  not touched in any way.  Managing the pointer is the user's
533        *  responsibility.
534        */
535       _GLIBCXX_ABI_TAG_CXX11
536       iterator
537       erase(const_iterator __position)
538       { return _M_t.erase(__position); }
539 #else
540       /**
541        *  @brief Erases an element from a %multiset.
542        *  @param  __position  An iterator pointing to the element to be erased.
543        *
544        *  This function erases an element, pointed to by the given iterator,
545        *  from a %multiset.  Note that this function only erases the element,
546        *  and that if the element is itself a pointer, the pointed-to memory is
547        *  not touched in any way.  Managing the pointer is the user's
548        *  responsibility.
549        */
550       void
551       erase(iterator __position)
552       { _M_t.erase(__position); }
553 #endif
554 
555       /**
556        *  @brief Erases elements according to the provided key.
557        *  @param  __x  Key of element to be erased.
558        *  @return  The number of elements erased.
559        *
560        *  This function erases all elements located by the given key from a
561        *  %multiset.
562        *  Note that this function only erases the element, and that if
563        *  the element is itself a pointer, the pointed-to memory is not touched
564        *  in any way.  Managing the pointer is the user's responsibility.
565        */
566       size_type
567       erase(const key_type& __x)
568       { return _M_t.erase(__x); }
569 
570 #if __cplusplus >= 201103L
571       // _GLIBCXX_RESOLVE_LIB_DEFECTS
572       // DR 130. Associative erase should return an iterator.
573       /**
574        *  @brief Erases a [first,last) range of elements from a %multiset.
575        *  @param  __first  Iterator pointing to the start of the range to be
576        *                   erased.
577        *  @param __last Iterator pointing to the end of the range to
578        *                be erased.
579        *  @return The iterator @a last.
580        *
581        *  This function erases a sequence of elements from a %multiset.
582        *  Note that this function only erases the elements, and that if
583        *  the elements themselves are pointers, the pointed-to memory is not
584        *  touched in any way.  Managing the pointer is the user's
585        *  responsibility.
586        */
587       _GLIBCXX_ABI_TAG_CXX11
588       iterator
589       erase(const_iterator __first, const_iterator __last)
590       { return _M_t.erase(__first, __last); }
591 #else
592       /**
593        *  @brief Erases a [first,last) range of elements from a %multiset.
594        *  @param  first  Iterator pointing to the start of the range to be
595        *                 erased.
596        *  @param  last  Iterator pointing to the end of the range to be erased.
597        *
598        *  This function erases a sequence of elements from a %multiset.
599        *  Note that this function only erases the elements, and that if
600        *  the elements themselves are pointers, the pointed-to memory is not
601        *  touched in any way.  Managing the pointer is the user's
602        *  responsibility.
603        */
604       void
605       erase(iterator __first, iterator __last)
606       { _M_t.erase(__first, __last); }
607 #endif
608 
609       /**
610        *  Erases all elements in a %multiset.  Note that this function only
611        *  erases the elements, and that if the elements themselves are pointers,
612        *  the pointed-to memory is not touched in any way.  Managing the pointer
613        *  is the user's responsibility.
614        */
615       void
616       clear() _GLIBCXX_NOEXCEPT
617       { _M_t.clear(); }
618 
619       // multiset operations:
620 
621       /**
622        *  @brief Finds the number of elements with given key.
623        *  @param  __x  Key of elements to be located.
624        *  @return Number of elements with specified key.
625        */
626       size_type
627       count(const key_type& __x) const
628       { return _M_t.count(__x); }
629 
630       // _GLIBCXX_RESOLVE_LIB_DEFECTS
631       // 214.  set::find() missing const overload
632       //@{
633       /**
634        *  @brief Tries to locate an element in a %set.
635        *  @param  __x  Element to be located.
636        *  @return  Iterator pointing to sought-after element, or end() if not
637        *           found.
638        *
639        *  This function takes a key and tries to locate the element with which
640        *  the key matches.  If successful the function returns an iterator
641        *  pointing to the sought after element.  If unsuccessful it returns the
642        *  past-the-end ( @c end() ) iterator.
643        */
644       iterator
645       find(const key_type& __x)
646       { return _M_t.find(__x); }
647 
648       const_iterator
649       find(const key_type& __x) const
650       { return _M_t.find(__x); }
651       //@}
652 
653       //@{
654       /**
655        *  @brief Finds the beginning of a subsequence matching given key.
656        *  @param  __x  Key to be located.
657        *  @return  Iterator pointing to first element equal to or greater
658        *           than key, or end().
659        *
660        *  This function returns the first element of a subsequence of elements
661        *  that matches the given key.  If unsuccessful it returns an iterator
662        *  pointing to the first element that has a greater value than given key
663        *  or end() if no such element exists.
664        */
665       iterator
666       lower_bound(const key_type& __x)
667       { return _M_t.lower_bound(__x); }
668 
669       const_iterator
670       lower_bound(const key_type& __x) const
671       { return _M_t.lower_bound(__x); }
672       //@}
673 
674       //@{
675       /**
676        *  @brief Finds the end of a subsequence matching given key.
677        *  @param  __x  Key to be located.
678        *  @return Iterator pointing to the first element
679        *          greater than key, or end().
680        */
681       iterator
682       upper_bound(const key_type& __x)
683       { return _M_t.upper_bound(__x); }
684 
685       const_iterator
686       upper_bound(const key_type& __x) const
687       { return _M_t.upper_bound(__x); }
688       //@}
689 
690       //@{
691       /**
692        *  @brief Finds a subsequence matching given key.
693        *  @param  __x  Key to be located.
694        *  @return  Pair of iterators that possibly points to the subsequence
695        *           matching given key.
696        *
697        *  This function is equivalent to
698        *  @code
699        *    std::make_pair(c.lower_bound(val),
700        *                   c.upper_bound(val))
701        *  @endcode
702        *  (but is faster than making the calls separately).
703        *
704        *  This function probably only makes sense for multisets.
705        */
706       std::pair<iterator, iterator>
707       equal_range(const key_type& __x)
708       { return _M_t.equal_range(__x); }
709 
710       std::pair<const_iterator, const_iterator>
711       equal_range(const key_type& __x) const
712       { return _M_t.equal_range(__x); }
713       //@}
714 
715       template<typename _K1, typename _C1, typename _A1>
716         friend bool
717         operator==(const multiset<_K1, _C1, _A1>&,
718 		   const multiset<_K1, _C1, _A1>&);
719 
720       template<typename _K1, typename _C1, typename _A1>
721         friend bool
722         operator< (const multiset<_K1, _C1, _A1>&,
723 		   const multiset<_K1, _C1, _A1>&);
724     };
725 
726   /**
727    *  @brief  Multiset equality comparison.
728    *  @param  __x  A %multiset.
729    *  @param  __y  A %multiset of the same type as @a __x.
730    *  @return  True iff the size and elements of the multisets are equal.
731    *
732    *  This is an equivalence relation.  It is linear in the size of the
733    *  multisets.
734    *  Multisets are considered equivalent if their sizes are equal, and if
735    *  corresponding elements compare equal.
736   */
737   template<typename _Key, typename _Compare, typename _Alloc>
738     inline bool
739     operator==(const multiset<_Key, _Compare, _Alloc>& __x,
740 	       const multiset<_Key, _Compare, _Alloc>& __y)
741     { return __x._M_t == __y._M_t; }
742 
743   /**
744    *  @brief  Multiset ordering relation.
745    *  @param  __x  A %multiset.
746    *  @param  __y  A %multiset of the same type as @a __x.
747    *  @return  True iff @a __x is lexicographically less than @a __y.
748    *
749    *  This is a total ordering relation.  It is linear in the size of the
750    *  maps.  The elements must be comparable with @c <.
751    *
752    *  See std::lexicographical_compare() for how the determination is made.
753   */
754   template<typename _Key, typename _Compare, typename _Alloc>
755     inline bool
756     operator<(const multiset<_Key, _Compare, _Alloc>& __x,
757 	      const multiset<_Key, _Compare, _Alloc>& __y)
758     { return __x._M_t < __y._M_t; }
759 
760   ///  Returns !(x == y).
761   template<typename _Key, typename _Compare, typename _Alloc>
762     inline bool
763     operator!=(const multiset<_Key, _Compare, _Alloc>& __x,
764 	       const multiset<_Key, _Compare, _Alloc>& __y)
765     { return !(__x == __y); }
766 
767   ///  Returns y < x.
768   template<typename _Key, typename _Compare, typename _Alloc>
769     inline bool
770     operator>(const multiset<_Key,_Compare,_Alloc>& __x,
771 	      const multiset<_Key,_Compare,_Alloc>& __y)
772     { return __y < __x; }
773 
774   ///  Returns !(y < x)
775   template<typename _Key, typename _Compare, typename _Alloc>
776     inline bool
777     operator<=(const multiset<_Key, _Compare, _Alloc>& __x,
778 	       const multiset<_Key, _Compare, _Alloc>& __y)
779     { return !(__y < __x); }
780 
781   ///  Returns !(x < y)
782   template<typename _Key, typename _Compare, typename _Alloc>
783     inline bool
784     operator>=(const multiset<_Key, _Compare, _Alloc>& __x,
785 	       const multiset<_Key, _Compare, _Alloc>& __y)
786     { return !(__x < __y); }
787 
788   /// See std::multiset::swap().
789   template<typename _Key, typename _Compare, typename _Alloc>
790     inline void
791     swap(multiset<_Key, _Compare, _Alloc>& __x,
792 	 multiset<_Key, _Compare, _Alloc>& __y)
793     { __x.swap(__y); }
794 
795 _GLIBCXX_END_NAMESPACE_CONTAINER
796 } // namespace std
797 
798 #endif /* _STL_MULTISET_H */
799