1// Multiset implementation -*- C++ -*-
2
3// Copyright (C) 2001-2014 Free Software Foundation, Inc.
4//
5// This file is part of the GNU ISO C++ Library.  This library is free
6// software; you can redistribute it and/or modify it under the
7// terms of the GNU General Public License as published by the
8// Free Software Foundation; either version 3, or (at your option)
9// any later version.
10
11// This library is distributed in the hope that it will be useful,
12// but WITHOUT ANY WARRANTY; without even the implied warranty of
13// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14// GNU General Public License for more details.
15
16// Under Section 7 of GPL version 3, you are granted additional
17// permissions described in the GCC Runtime Library Exception, version
18// 3.1, as published by the Free Software Foundation.
19
20// You should have received a copy of the GNU General Public License and
21// a copy of the GCC Runtime Library Exception along with this program;
22// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
23// <http://www.gnu.org/licenses/>.
24
25/*
26 *
27 * Copyright (c) 1994
28 * Hewlett-Packard Company
29 *
30 * Permission to use, copy, modify, distribute and sell this software
31 * and its documentation for any purpose is hereby granted without fee,
32 * provided that the above copyright notice appear in all copies and
33 * that both that copyright notice and this permission notice appear
34 * in supporting documentation.  Hewlett-Packard Company makes no
35 * representations about the suitability of this software for any
36 * purpose.  It is provided "as is" without express or implied warranty.
37 *
38 *
39 * Copyright (c) 1996
40 * Silicon Graphics Computer Systems, Inc.
41 *
42 * Permission to use, copy, modify, distribute and sell this software
43 * and its documentation for any purpose is hereby granted without fee,
44 * provided that the above copyright notice appear in all copies and
45 * that both that copyright notice and this permission notice appear
46 * in supporting documentation.  Silicon Graphics makes no
47 * representations about the suitability of this software for any
48 * purpose.  It is provided "as is" without express or implied warranty.
49 */
50
51/** @file bits/stl_multiset.h
52 *  This is an internal header file, included by other library headers.
53 *  Do not attempt to use it directly. @headername{set}
54 */
55
56#ifndef _STL_MULTISET_H
57#define _STL_MULTISET_H 1
58
59#include <bits/concept_check.h>
60#if __cplusplus >= 201103L
61#include <initializer_list>
62#endif
63
64namespace std _GLIBCXX_VISIBILITY(default)
65{
66_GLIBCXX_BEGIN_NAMESPACE_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 __gnu_cxx::__alloc_traits<_Alloc>::template
112	rebind<_Key>::other _Key_alloc_type;
113
114      typedef _Rb_tree<key_type, value_type, _Identity<value_type>,
115		       key_compare, _Key_alloc_type> _Rep_type;
116      /// The actual tree structure.
117      _Rep_type _M_t;
118
119      typedef __gnu_cxx::__alloc_traits<_Key_alloc_type> _Alloc_traits;
120
121    public:
122      typedef typename _Alloc_traits::pointer		    pointer;
123      typedef typename _Alloc_traits::const_pointer	    const_pointer;
124      typedef typename _Alloc_traits::reference		    reference;
125      typedef typename _Alloc_traits::const_reference	    const_reference;
126      // _GLIBCXX_RESOLVE_LIB_DEFECTS
127      // DR 103. set::iterator is required to be modifiable,
128      // but this allows modification of keys.
129      typedef typename _Rep_type::const_iterator            iterator;
130      typedef typename _Rep_type::const_iterator            const_iterator;
131      typedef typename _Rep_type::const_reverse_iterator    reverse_iterator;
132      typedef typename _Rep_type::const_reverse_iterator const_reverse_iterator;
133      typedef typename _Rep_type::size_type                 size_type;
134      typedef typename _Rep_type::difference_type           difference_type;
135
136      // allocation/deallocation
137      /**
138       *  @brief  Default constructor creates no elements.
139       */
140      multiset()
141      : _M_t() { }
142
143      /**
144       *  @brief  Creates a %multiset with no elements.
145       *  @param  __comp  Comparator to use.
146       *  @param  __a  An allocator object.
147       */
148      explicit
149      multiset(const _Compare& __comp,
150	       const allocator_type& __a = allocator_type())
151      : _M_t(__comp, _Key_alloc_type(__a)) { }
152
153      /**
154       *  @brief  Builds a %multiset from a range.
155       *  @param  __first  An input iterator.
156       *  @param  __last  An input iterator.
157       *
158       *  Create a %multiset consisting of copies of the elements from
159       *  [first,last).  This is linear in N if the range is already sorted,
160       *  and NlogN otherwise (where N is distance(__first,__last)).
161       */
162      template<typename _InputIterator>
163        multiset(_InputIterator __first, _InputIterator __last)
164	: _M_t()
165        { _M_t._M_insert_equal(__first, __last); }
166
167      /**
168       *  @brief  Builds a %multiset from a range.
169       *  @param  __first  An input iterator.
170       *  @param  __last  An input iterator.
171       *  @param  __comp  A comparison functor.
172       *  @param  __a  An allocator object.
173       *
174       *  Create a %multiset consisting of copies of the elements from
175       *  [__first,__last).  This is linear in N if the range is already sorted,
176       *  and NlogN otherwise (where N is distance(__first,__last)).
177       */
178      template<typename _InputIterator>
179        multiset(_InputIterator __first, _InputIterator __last,
180		 const _Compare& __comp,
181		 const allocator_type& __a = allocator_type())
182	: _M_t(__comp, _Key_alloc_type(__a))
183        { _M_t._M_insert_equal(__first, __last); }
184
185      /**
186       *  @brief  %Multiset copy constructor.
187       *  @param  __x  A %multiset of identical element and allocator types.
188       *
189       *  The newly-created %multiset uses a copy of the allocation object used
190       *  by @a __x.
191       */
192      multiset(const multiset& __x)
193      : _M_t(__x._M_t) { }
194
195#if __cplusplus >= 201103L
196     /**
197       *  @brief  %Multiset move constructor.
198       *  @param  __x  A %multiset of identical element and allocator types.
199       *
200       *  The newly-created %multiset contains the exact contents of @a __x.
201       *  The contents of @a __x are a valid, but unspecified %multiset.
202       */
203      multiset(multiset&& __x)
204      noexcept(is_nothrow_copy_constructible<_Compare>::value)
205      : _M_t(std::move(__x._M_t)) { }
206
207      /**
208       *  @brief  Builds a %multiset from an initializer_list.
209       *  @param  __l  An initializer_list.
210       *  @param  __comp  A comparison functor.
211       *  @param  __a  An allocator object.
212       *
213       *  Create a %multiset consisting of copies of the elements from
214       *  the list.  This is linear in N if the list is already sorted,
215       *  and NlogN otherwise (where N is @a __l.size()).
216       */
217      multiset(initializer_list<value_type> __l,
218	       const _Compare& __comp = _Compare(),
219	       const allocator_type& __a = allocator_type())
220      : _M_t(__comp, _Key_alloc_type(__a))
221      { _M_t._M_insert_equal(__l.begin(), __l.end()); }
222
223      /// Allocator-extended default constructor.
224      explicit
225      multiset(const allocator_type& __a)
226      : _M_t(_Compare(), _Key_alloc_type(__a)) { }
227
228      /// Allocator-extended copy constructor.
229      multiset(const multiset& __m, const allocator_type& __a)
230      : _M_t(__m._M_t, _Key_alloc_type(__a)) { }
231
232      /// Allocator-extended move constructor.
233      multiset(multiset&& __m, const allocator_type& __a)
234      noexcept(is_nothrow_copy_constructible<_Compare>::value
235	       && _Alloc_traits::_S_always_equal())
236      : _M_t(std::move(__m._M_t), _Key_alloc_type(__a)) { }
237
238      /// Allocator-extended initialier-list constructor.
239      multiset(initializer_list<value_type> __l, const allocator_type& __a)
240      : _M_t(_Compare(), _Key_alloc_type(__a))
241      { _M_t._M_insert_equal(__l.begin(), __l.end()); }
242
243      /// Allocator-extended range constructor.
244      template<typename _InputIterator>
245        multiset(_InputIterator __first, _InputIterator __last,
246		 const allocator_type& __a)
247	: _M_t(_Compare(), _Key_alloc_type(__a))
248        { _M_t._M_insert_equal(__first, __last); }
249#endif
250
251      /**
252       *  @brief  %Multiset assignment operator.
253       *  @param  __x  A %multiset of identical element and allocator types.
254       *
255       *  All the elements of @a __x are copied, but unlike the copy
256       *  constructor, the allocator object is not copied.
257       */
258      multiset&
259      operator=(const multiset& __x)
260      {
261	_M_t = __x._M_t;
262	return *this;
263      }
264
265#if __cplusplus >= 201103L
266      /**
267       *  @brief  %Multiset move assignment operator.
268       *  @param  __x  A %multiset of identical element and allocator types.
269       *
270       *  The contents of @a __x are moved into this %multiset (without
271       *  copying if the allocators compare equal or get moved on assignment).
272       *  Afterwards @a __x is in a valid, but unspecified state.
273       */
274      multiset&
275      operator=(multiset&& __x) noexcept(_Alloc_traits::_S_nothrow_move())
276      {
277	if (!_M_t._M_move_assign(__x._M_t))
278	  {
279	    // The rvalue's allocator cannot be moved and is not equal,
280	    // so we need to individually move each element.
281	    clear();
282	    insert(std::__make_move_if_noexcept_iterator(__x._M_t.begin()),
283		   std::__make_move_if_noexcept_iterator(__x._M_t.end()));
284	    __x.clear();
285	  }
286	return *this;
287      }
288
289      /**
290       *  @brief  %Multiset list assignment operator.
291       *  @param  __l  An initializer_list.
292       *
293       *  This function fills a %multiset with copies of the elements in the
294       *  initializer list @a __l.
295       *
296       *  Note that the assignment completely changes the %multiset and
297       *  that the resulting %multiset's size is the same as the number
298       *  of elements assigned.  Old data may be lost.
299       */
300      multiset&
301      operator=(initializer_list<value_type> __l)
302      {
303	this->clear();
304	this->insert(__l.begin(), __l.end());
305	return *this;
306      }
307#endif
308
309      // accessors:
310
311      ///  Returns the comparison object.
312      key_compare
313      key_comp() const
314      { return _M_t.key_comp(); }
315      ///  Returns the comparison object.
316      value_compare
317      value_comp() const
318      { return _M_t.key_comp(); }
319      ///  Returns the memory allocation object.
320      allocator_type
321      get_allocator() const _GLIBCXX_NOEXCEPT
322      { return allocator_type(_M_t.get_allocator()); }
323
324      /**
325       *  Returns a read-only (constant) iterator that points to the first
326       *  element in the %multiset.  Iteration is done in ascending order
327       *  according to the keys.
328       */
329      iterator
330      begin() const _GLIBCXX_NOEXCEPT
331      { return _M_t.begin(); }
332
333      /**
334       *  Returns a read-only (constant) iterator that points one past the last
335       *  element in the %multiset.  Iteration is done in ascending order
336       *  according to the keys.
337       */
338      iterator
339      end() const _GLIBCXX_NOEXCEPT
340      { return _M_t.end(); }
341
342      /**
343       *  Returns a read-only (constant) reverse iterator that points to the
344       *  last element in the %multiset.  Iteration is done in descending order
345       *  according to the keys.
346       */
347      reverse_iterator
348      rbegin() const _GLIBCXX_NOEXCEPT
349      { return _M_t.rbegin(); }
350
351      /**
352       *  Returns a read-only (constant) reverse iterator that points to the
353       *  last element in the %multiset.  Iteration is done in descending order
354       *  according to the keys.
355       */
356      reverse_iterator
357      rend() const _GLIBCXX_NOEXCEPT
358      { return _M_t.rend(); }
359
360#if __cplusplus >= 201103L
361      /**
362       *  Returns a read-only (constant) iterator that points to the first
363       *  element in the %multiset.  Iteration is done in ascending order
364       *  according to the keys.
365       */
366      iterator
367      cbegin() const noexcept
368      { return _M_t.begin(); }
369
370      /**
371       *  Returns a read-only (constant) iterator that points one past the last
372       *  element in the %multiset.  Iteration is done in ascending order
373       *  according to the keys.
374       */
375      iterator
376      cend() const noexcept
377      { return _M_t.end(); }
378
379      /**
380       *  Returns a read-only (constant) reverse iterator that points to the
381       *  last element in the %multiset.  Iteration is done in descending order
382       *  according to the keys.
383       */
384      reverse_iterator
385      crbegin() const noexcept
386      { return _M_t.rbegin(); }
387
388      /**
389       *  Returns a read-only (constant) reverse iterator that points to the
390       *  last element in the %multiset.  Iteration is done in descending order
391       *  according to the keys.
392       */
393      reverse_iterator
394      crend() const noexcept
395      { return _M_t.rend(); }
396#endif
397
398      ///  Returns true if the %set is empty.
399      bool
400      empty() const _GLIBCXX_NOEXCEPT
401      { return _M_t.empty(); }
402
403      ///  Returns the size of the %set.
404      size_type
405      size() const _GLIBCXX_NOEXCEPT
406      { return _M_t.size(); }
407
408      ///  Returns the maximum size of the %set.
409      size_type
410      max_size() const _GLIBCXX_NOEXCEPT
411      { return _M_t.max_size(); }
412
413      /**
414       *  @brief  Swaps data with another %multiset.
415       *  @param  __x  A %multiset of the same element and allocator types.
416       *
417       *  This exchanges the elements between two multisets in constant time.
418       *  (It is only swapping a pointer, an integer, and an instance of the @c
419       *  Compare type (which itself is often stateless and empty), so it should
420       *  be quite fast.)
421       *  Note that the global std::swap() function is specialized such that
422       *  std::swap(s1,s2) will feed to this function.
423       */
424      void
425      swap(multiset& __x)
426#if __cplusplus >= 201103L
427      noexcept(_Alloc_traits::_S_nothrow_swap())
428#endif
429      { _M_t.swap(__x._M_t); }
430
431      // insert/erase
432#if __cplusplus >= 201103L
433      /**
434       *  @brief Builds and inserts an element into the %multiset.
435       *  @param  __args  Arguments used to generate the element instance to be
436       *                 inserted.
437       *  @return An iterator that points to the inserted element.
438       *
439       *  This function inserts an element into the %multiset.  Contrary
440       *  to a std::set the %multiset does not rely on unique keys and thus
441       *  multiple copies of the same element can be inserted.
442       *
443       *  Insertion requires logarithmic time.
444       */
445      template<typename... _Args>
446	iterator
447	emplace(_Args&&... __args)
448	{ return _M_t._M_emplace_equal(std::forward<_Args>(__args)...); }
449
450      /**
451       *  @brief Builds and inserts an element into the %multiset.
452       *  @param  __pos  An iterator that serves as a hint as to where the
453       *                element should be inserted.
454       *  @param  __args  Arguments used to generate the element instance to be
455       *                 inserted.
456       *  @return An iterator that points to the inserted element.
457       *
458       *  This function inserts an element into the %multiset.  Contrary
459       *  to a std::set the %multiset does not rely on unique keys and thus
460       *  multiple copies of the same element can be inserted.
461       *
462       *  Note that the first parameter is only a hint and can potentially
463       *  improve the performance of the insertion process.  A bad hint would
464       *  cause no gains in efficiency.
465       *
466       *  See http://gcc.gnu.org/onlinedocs/libstdc++/manual/bk01pt07ch17.html
467       *  for more on @a hinting.
468       *
469       *  Insertion requires logarithmic time (if the hint is not taken).
470       */
471      template<typename... _Args>
472	iterator
473	emplace_hint(const_iterator __pos, _Args&&... __args)
474	{
475	  return _M_t._M_emplace_hint_equal(__pos,
476					    std::forward<_Args>(__args)...);
477	}
478#endif
479
480      /**
481       *  @brief Inserts an element into the %multiset.
482       *  @param  __x  Element to be inserted.
483       *  @return An iterator that points to the inserted element.
484       *
485       *  This function inserts an element into the %multiset.  Contrary
486       *  to a std::set the %multiset does not rely on unique keys and thus
487       *  multiple copies of the same element can be inserted.
488       *
489       *  Insertion requires logarithmic time.
490       */
491      iterator
492      insert(const value_type& __x)
493      { return _M_t._M_insert_equal(__x); }
494
495#if __cplusplus >= 201103L
496      iterator
497      insert(value_type&& __x)
498      { return _M_t._M_insert_equal(std::move(__x)); }
499#endif
500
501      /**
502       *  @brief Inserts an element into the %multiset.
503       *  @param  __position  An iterator that serves as a hint as to where the
504       *                    element should be inserted.
505       *  @param  __x  Element to be inserted.
506       *  @return An iterator that points to the inserted element.
507       *
508       *  This function inserts an element into the %multiset.  Contrary
509       *  to a std::set the %multiset does not rely on unique keys and thus
510       *  multiple copies of the same element can be inserted.
511       *
512       *  Note that the first parameter is only a hint and can potentially
513       *  improve the performance of the insertion process.  A bad hint would
514       *  cause no gains in efficiency.
515       *
516       *  See http://gcc.gnu.org/onlinedocs/libstdc++/manual/bk01pt07ch17.html
517       *  for more on @a hinting.
518       *
519       *  Insertion requires logarithmic time (if the hint is not taken).
520       */
521      iterator
522      insert(const_iterator __position, const value_type& __x)
523      { return _M_t._M_insert_equal_(__position, __x); }
524
525#if __cplusplus >= 201103L
526      iterator
527      insert(const_iterator __position, value_type&& __x)
528      { return _M_t._M_insert_equal_(__position, std::move(__x)); }
529#endif
530
531      /**
532       *  @brief A template function that tries to insert a range of elements.
533       *  @param  __first  Iterator pointing to the start of the range to be
534       *                   inserted.
535       *  @param  __last  Iterator pointing to the end of the range.
536       *
537       *  Complexity similar to that of the range constructor.
538       */
539      template<typename _InputIterator>
540        void
541        insert(_InputIterator __first, _InputIterator __last)
542        { _M_t._M_insert_equal(__first, __last); }
543
544#if __cplusplus >= 201103L
545      /**
546       *  @brief Attempts to insert a list of elements into the %multiset.
547       *  @param  __l  A std::initializer_list<value_type> of elements
548       *               to be inserted.
549       *
550       *  Complexity similar to that of the range constructor.
551       */
552      void
553      insert(initializer_list<value_type> __l)
554      { this->insert(__l.begin(), __l.end()); }
555#endif
556
557#if __cplusplus >= 201103L
558      // _GLIBCXX_RESOLVE_LIB_DEFECTS
559      // DR 130. Associative erase should return an iterator.
560      /**
561       *  @brief Erases an element from a %multiset.
562       *  @param  __position  An iterator pointing to the element to be erased.
563       *  @return An iterator pointing to the element immediately following
564       *          @a position prior to the element being erased. If no such
565       *          element exists, end() is returned.
566       *
567       *  This function erases an element, pointed to by the given iterator,
568       *  from a %multiset.  Note that this function only erases the element,
569       *  and that if the element is itself a pointer, the pointed-to memory is
570       *  not touched in any way.  Managing the pointer is the user's
571       *  responsibility.
572       */
573      _GLIBCXX_ABI_TAG_CXX11
574      iterator
575      erase(const_iterator __position)
576      { return _M_t.erase(__position); }
577#else
578      /**
579       *  @brief Erases an element from a %multiset.
580       *  @param  __position  An iterator pointing to the element to be erased.
581       *
582       *  This function erases an element, pointed to by the given iterator,
583       *  from a %multiset.  Note that this function only erases the element,
584       *  and that if the element is itself a pointer, the pointed-to memory is
585       *  not touched in any way.  Managing the pointer is the user's
586       *  responsibility.
587       */
588      void
589      erase(iterator __position)
590      { _M_t.erase(__position); }
591#endif
592
593      /**
594       *  @brief Erases elements according to the provided key.
595       *  @param  __x  Key of element to be erased.
596       *  @return  The number of elements erased.
597       *
598       *  This function erases all elements located by the given key from a
599       *  %multiset.
600       *  Note that this function only erases the element, and that if
601       *  the element is itself a pointer, the pointed-to memory is not touched
602       *  in any way.  Managing the pointer is the user's responsibility.
603       */
604      size_type
605      erase(const key_type& __x)
606      { return _M_t.erase(__x); }
607
608#if __cplusplus >= 201103L
609      // _GLIBCXX_RESOLVE_LIB_DEFECTS
610      // DR 130. Associative erase should return an iterator.
611      /**
612       *  @brief Erases a [first,last) range of elements from a %multiset.
613       *  @param  __first  Iterator pointing to the start of the range to be
614       *                   erased.
615       *  @param __last Iterator pointing to the end of the range to
616       *                be erased.
617       *  @return The iterator @a last.
618       *
619       *  This function erases a sequence of elements from a %multiset.
620       *  Note that this function only erases the elements, and that if
621       *  the elements themselves are pointers, the pointed-to memory is not
622       *  touched in any way.  Managing the pointer is the user's
623       *  responsibility.
624       */
625      _GLIBCXX_ABI_TAG_CXX11
626      iterator
627      erase(const_iterator __first, const_iterator __last)
628      { return _M_t.erase(__first, __last); }
629#else
630      /**
631       *  @brief Erases a [first,last) range of elements from a %multiset.
632       *  @param  first  Iterator pointing to the start of the range to be
633       *                 erased.
634       *  @param  last  Iterator pointing to the end of the range to be erased.
635       *
636       *  This function erases a sequence of elements from a %multiset.
637       *  Note that this function only erases the elements, and that if
638       *  the elements themselves are pointers, the pointed-to memory is not
639       *  touched in any way.  Managing the pointer is the user's
640       *  responsibility.
641       */
642      void
643      erase(iterator __first, iterator __last)
644      { _M_t.erase(__first, __last); }
645#endif
646
647      /**
648       *  Erases all elements in a %multiset.  Note that this function only
649       *  erases the elements, and that if the elements themselves are pointers,
650       *  the pointed-to memory is not touched in any way.  Managing the pointer
651       *  is the user's responsibility.
652       */
653      void
654      clear() _GLIBCXX_NOEXCEPT
655      { _M_t.clear(); }
656
657      // multiset operations:
658
659      /**
660       *  @brief Finds the number of elements with given key.
661       *  @param  __x  Key of elements to be located.
662       *  @return Number of elements with specified key.
663       */
664      size_type
665      count(const key_type& __x) const
666      { return _M_t.count(__x); }
667
668      // _GLIBCXX_RESOLVE_LIB_DEFECTS
669      // 214.  set::find() missing const overload
670      //@{
671      /**
672       *  @brief Tries to locate an element in a %set.
673       *  @param  __x  Element to be located.
674       *  @return  Iterator pointing to sought-after element, or end() if not
675       *           found.
676       *
677       *  This function takes a key and tries to locate the element with which
678       *  the key matches.  If successful the function returns an iterator
679       *  pointing to the sought after element.  If unsuccessful it returns the
680       *  past-the-end ( @c end() ) iterator.
681       */
682      iterator
683      find(const key_type& __x)
684      { return _M_t.find(__x); }
685
686      const_iterator
687      find(const key_type& __x) const
688      { return _M_t.find(__x); }
689      //@}
690
691      //@{
692      /**
693       *  @brief Finds the beginning of a subsequence matching given key.
694       *  @param  __x  Key to be located.
695       *  @return  Iterator pointing to first element equal to or greater
696       *           than key, or end().
697       *
698       *  This function returns the first element of a subsequence of elements
699       *  that matches the given key.  If unsuccessful it returns an iterator
700       *  pointing to the first element that has a greater value than given key
701       *  or end() if no such element exists.
702       */
703      iterator
704      lower_bound(const key_type& __x)
705      { return _M_t.lower_bound(__x); }
706
707      const_iterator
708      lower_bound(const key_type& __x) const
709      { return _M_t.lower_bound(__x); }
710      //@}
711
712      //@{
713      /**
714       *  @brief Finds the end of a subsequence matching given key.
715       *  @param  __x  Key to be located.
716       *  @return Iterator pointing to the first element
717       *          greater than key, or end().
718       */
719      iterator
720      upper_bound(const key_type& __x)
721      { return _M_t.upper_bound(__x); }
722
723      const_iterator
724      upper_bound(const key_type& __x) const
725      { return _M_t.upper_bound(__x); }
726      //@}
727
728      //@{
729      /**
730       *  @brief Finds a subsequence matching given key.
731       *  @param  __x  Key to be located.
732       *  @return  Pair of iterators that possibly points to the subsequence
733       *           matching given key.
734       *
735       *  This function is equivalent to
736       *  @code
737       *    std::make_pair(c.lower_bound(val),
738       *                   c.upper_bound(val))
739       *  @endcode
740       *  (but is faster than making the calls separately).
741       *
742       *  This function probably only makes sense for multisets.
743       */
744      std::pair<iterator, iterator>
745      equal_range(const key_type& __x)
746      { return _M_t.equal_range(__x); }
747
748      std::pair<const_iterator, const_iterator>
749      equal_range(const key_type& __x) const
750      { return _M_t.equal_range(__x); }
751      //@}
752
753      template<typename _K1, typename _C1, typename _A1>
754        friend bool
755        operator==(const multiset<_K1, _C1, _A1>&,
756		   const multiset<_K1, _C1, _A1>&);
757
758      template<typename _K1, typename _C1, typename _A1>
759        friend bool
760        operator< (const multiset<_K1, _C1, _A1>&,
761		   const multiset<_K1, _C1, _A1>&);
762    };
763
764  /**
765   *  @brief  Multiset equality comparison.
766   *  @param  __x  A %multiset.
767   *  @param  __y  A %multiset of the same type as @a __x.
768   *  @return  True iff the size and elements of the multisets are equal.
769   *
770   *  This is an equivalence relation.  It is linear in the size of the
771   *  multisets.
772   *  Multisets are considered equivalent if their sizes are equal, and if
773   *  corresponding elements compare equal.
774  */
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 __x._M_t == __y._M_t; }
780
781  /**
782   *  @brief  Multiset ordering relation.
783   *  @param  __x  A %multiset.
784   *  @param  __y  A %multiset of the same type as @a __x.
785   *  @return  True iff @a __x is lexicographically less than @a __y.
786   *
787   *  This is a total ordering relation.  It is linear in the size of the
788   *  sets.  The elements must be comparable with @c <.
789   *
790   *  See std::lexicographical_compare() for how the determination is made.
791  */
792  template<typename _Key, typename _Compare, typename _Alloc>
793    inline bool
794    operator<(const multiset<_Key, _Compare, _Alloc>& __x,
795	      const multiset<_Key, _Compare, _Alloc>& __y)
796    { return __x._M_t < __y._M_t; }
797
798  ///  Returns !(x == y).
799  template<typename _Key, typename _Compare, typename _Alloc>
800    inline bool
801    operator!=(const multiset<_Key, _Compare, _Alloc>& __x,
802	       const multiset<_Key, _Compare, _Alloc>& __y)
803    { return !(__x == __y); }
804
805  ///  Returns y < x.
806  template<typename _Key, typename _Compare, typename _Alloc>
807    inline bool
808    operator>(const multiset<_Key,_Compare,_Alloc>& __x,
809	      const multiset<_Key,_Compare,_Alloc>& __y)
810    { return __y < __x; }
811
812  ///  Returns !(y < x)
813  template<typename _Key, typename _Compare, typename _Alloc>
814    inline bool
815    operator<=(const multiset<_Key, _Compare, _Alloc>& __x,
816	       const multiset<_Key, _Compare, _Alloc>& __y)
817    { return !(__y < __x); }
818
819  ///  Returns !(x < y)
820  template<typename _Key, typename _Compare, typename _Alloc>
821    inline bool
822    operator>=(const multiset<_Key, _Compare, _Alloc>& __x,
823	       const multiset<_Key, _Compare, _Alloc>& __y)
824    { return !(__x < __y); }
825
826  /// See std::multiset::swap().
827  template<typename _Key, typename _Compare, typename _Alloc>
828    inline void
829    swap(multiset<_Key, _Compare, _Alloc>& __x,
830	 multiset<_Key, _Compare, _Alloc>& __y)
831    { __x.swap(__y); }
832
833_GLIBCXX_END_NAMESPACE_CONTAINER
834} // namespace std
835
836#endif /* _STL_MULTISET_H */
837