1// Multimap implementation -*- C++ -*-
2
3// Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010
4// Free Software Foundation, Inc.
5//
6// This file is part of the GNU ISO C++ Library.  This library is free
7// software; you can redistribute it and/or modify it under the
8// terms of the GNU General Public License as published by the
9// Free Software Foundation; either version 3, or (at your option)
10// any later version.
11
12// This library is distributed in the hope that it will be useful,
13// but WITHOUT ANY WARRANTY; without even the implied warranty of
14// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15// GNU General Public License for more details.
16
17// Under Section 7 of GPL version 3, you are granted additional
18// permissions described in the GCC Runtime Library Exception, version
19// 3.1, as published by the Free Software Foundation.
20
21// You should have received a copy of the GNU General Public License and
22// a copy of the GCC Runtime Library Exception along with this program;
23// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
24// <http://www.gnu.org/licenses/>.
25
26/*
27 *
28 * Copyright (c) 1994
29 * Hewlett-Packard Company
30 *
31 * Permission to use, copy, modify, distribute and sell this software
32 * and its documentation for any purpose is hereby granted without fee,
33 * provided that the above copyright notice appear in all copies and
34 * that both that copyright notice and this permission notice appear
35 * in supporting documentation.  Hewlett-Packard Company makes no
36 * representations about the suitability of this software for any
37 * purpose.  It is provided "as is" without express or implied warranty.
38 *
39 *
40 * Copyright (c) 1996,1997
41 * Silicon Graphics Computer Systems, Inc.
42 *
43 * Permission to use, copy, modify, distribute and sell this software
44 * and its documentation for any purpose is hereby granted without fee,
45 * provided that the above copyright notice appear in all copies and
46 * that both that copyright notice and this permission notice appear
47 * in supporting documentation.  Silicon Graphics makes no
48 * representations about the suitability of this software for any
49 * purpose.  It is provided "as is" without express or implied warranty.
50 */
51
52/** @file stl_multimap.h
53 *  This is an internal header file, included by other library headers.
54 *  You should not attempt to use it directly.
55 */
56
57#ifndef _STL_MULTIMAP_H
58#define _STL_MULTIMAP_H 1
59
60#include <bits/concept_check.h>
61#include <initializer_list>
62
63_GLIBCXX_BEGIN_NESTED_NAMESPACE(std, _GLIBCXX_STD_D)
64
65  /**
66   *  @brief A standard container made up of (key,value) pairs, which can be
67   *  retrieved based on a key, in logarithmic time.
68   *
69   *  @ingroup associative_containers
70   *
71   *  Meets the requirements of a <a href="tables.html#65">container</a>, a
72   *  <a href="tables.html#66">reversible container</a>, and an
73   *  <a href="tables.html#69">associative container</a> (using equivalent
74   *  keys).  For a @c multimap<Key,T> the key_type is Key, the mapped_type
75   *  is T, and the value_type is std::pair<const Key,T>.
76   *
77   *  Multimaps support bidirectional iterators.
78   *
79   *  The private tree data is declared exactly the same way for map and
80   *  multimap; the distinction is made entirely in how the tree functions are
81   *  called (*_unique versus *_equal, same as the standard).
82  */
83  template <typename _Key, typename _Tp,
84	    typename _Compare = std::less<_Key>,
85	    typename _Alloc = std::allocator<std::pair<const _Key, _Tp> > >
86    class multimap
87    {
88    public:
89      typedef _Key                                          key_type;
90      typedef _Tp                                           mapped_type;
91      typedef std::pair<const _Key, _Tp>                    value_type;
92      typedef _Compare                                      key_compare;
93      typedef _Alloc                                        allocator_type;
94
95    private:
96      // concept requirements
97      typedef typename _Alloc::value_type                   _Alloc_value_type;
98      __glibcxx_class_requires(_Tp, _SGIAssignableConcept)
99      __glibcxx_class_requires4(_Compare, bool, _Key, _Key,
100				_BinaryFunctionConcept)
101      __glibcxx_class_requires2(value_type, _Alloc_value_type, _SameTypeConcept)
102
103    public:
104      class value_compare
105      : public std::binary_function<value_type, value_type, bool>
106      {
107	friend class multimap<_Key, _Tp, _Compare, _Alloc>;
108      protected:
109	_Compare comp;
110
111	value_compare(_Compare __c)
112	: comp(__c) { }
113
114      public:
115	bool operator()(const value_type& __x, const value_type& __y) const
116	{ return comp(__x.first, __y.first); }
117      };
118
119    private:
120      /// This turns a red-black tree into a [multi]map.
121      typedef typename _Alloc::template rebind<value_type>::other
122        _Pair_alloc_type;
123
124      typedef _Rb_tree<key_type, value_type, _Select1st<value_type>,
125		       key_compare, _Pair_alloc_type> _Rep_type;
126      /// The actual tree structure.
127      _Rep_type _M_t;
128
129    public:
130      // many of these are specified differently in ISO, but the following are
131      // "functionally equivalent"
132      typedef typename _Pair_alloc_type::pointer         pointer;
133      typedef typename _Pair_alloc_type::const_pointer   const_pointer;
134      typedef typename _Pair_alloc_type::reference       reference;
135      typedef typename _Pair_alloc_type::const_reference const_reference;
136      typedef typename _Rep_type::iterator               iterator;
137      typedef typename _Rep_type::const_iterator         const_iterator;
138      typedef typename _Rep_type::size_type              size_type;
139      typedef typename _Rep_type::difference_type        difference_type;
140      typedef typename _Rep_type::reverse_iterator       reverse_iterator;
141      typedef typename _Rep_type::const_reverse_iterator const_reverse_iterator;
142
143      // [23.3.2] construct/copy/destroy
144      // (get_allocator() is also listed in this section)
145      /**
146       *  @brief  Default constructor creates no elements.
147       */
148      multimap()
149      : _M_t() { }
150
151      /**
152       *  @brief  Creates a %multimap with no elements.
153       *  @param  comp  A comparison object.
154       *  @param  a  An allocator object.
155       */
156      explicit
157      multimap(const _Compare& __comp,
158	       const allocator_type& __a = allocator_type())
159      : _M_t(__comp, __a) { }
160
161      /**
162       *  @brief  %Multimap copy constructor.
163       *  @param  x  A %multimap of identical element and allocator types.
164       *
165       *  The newly-created %multimap uses a copy of the allocation object
166       *  used by @a x.
167       */
168      multimap(const multimap& __x)
169      : _M_t(__x._M_t) { }
170
171#ifdef __GXX_EXPERIMENTAL_CXX0X__
172      /**
173       *  @brief  %Multimap move constructor.
174       *  @param   x  A %multimap of identical element and allocator types.
175       *
176       *  The newly-created %multimap contains the exact contents of @a x.
177       *  The contents of @a x are a valid, but unspecified %multimap.
178       */
179      multimap(multimap&& __x)
180      : _M_t(std::forward<_Rep_type>(__x._M_t)) { }
181
182      /**
183       *  @brief  Builds a %multimap from an initializer_list.
184       *  @param  l  An initializer_list.
185       *  @param  comp  A comparison functor.
186       *  @param  a  An allocator object.
187       *
188       *  Create a %multimap consisting of copies of the elements from
189       *  the initializer_list.  This is linear in N if the list is already
190       *  sorted, and NlogN otherwise (where N is @a __l.size()).
191       */
192      multimap(initializer_list<value_type> __l,
193	       const _Compare& __comp = _Compare(),
194	       const allocator_type& __a = allocator_type())
195      : _M_t(__comp, __a)
196      { _M_t._M_insert_equal(__l.begin(), __l.end()); }
197#endif
198
199      /**
200       *  @brief  Builds a %multimap from a range.
201       *  @param  first  An input iterator.
202       *  @param  last  An input iterator.
203       *
204       *  Create a %multimap consisting of copies of the elements from
205       *  [first,last).  This is linear in N if the range is already sorted,
206       *  and NlogN otherwise (where N is distance(first,last)).
207       */
208      template<typename _InputIterator>
209        multimap(_InputIterator __first, _InputIterator __last)
210	: _M_t()
211        { _M_t._M_insert_equal(__first, __last); }
212
213      /**
214       *  @brief  Builds a %multimap from a range.
215       *  @param  first  An input iterator.
216       *  @param  last  An input iterator.
217       *  @param  comp  A comparison functor.
218       *  @param  a  An allocator object.
219       *
220       *  Create a %multimap consisting of copies of the elements from
221       *  [first,last).  This is linear in N if the range is already sorted,
222       *  and NlogN otherwise (where N is distance(first,last)).
223       */
224      template<typename _InputIterator>
225        multimap(_InputIterator __first, _InputIterator __last,
226		 const _Compare& __comp,
227		 const allocator_type& __a = allocator_type())
228        : _M_t(__comp, __a)
229        { _M_t._M_insert_equal(__first, __last); }
230
231      // FIXME There is no dtor declared, but we should have something generated
232      // by Doxygen.  I don't know what tags to add to this paragraph to make
233      // that happen:
234      /**
235       *  The dtor only erases the elements, and note that if the elements
236       *  themselves are pointers, the pointed-to memory is not touched in any
237       *  way.  Managing the pointer is the user's responsibility.
238       */
239
240      /**
241       *  @brief  %Multimap assignment operator.
242       *  @param  x  A %multimap of identical element and allocator types.
243       *
244       *  All the elements of @a x are copied, but unlike the copy constructor,
245       *  the allocator object is not copied.
246       */
247      multimap&
248      operator=(const multimap& __x)
249      {
250	_M_t = __x._M_t;
251	return *this;
252      }
253
254#ifdef __GXX_EXPERIMENTAL_CXX0X__
255      /**
256       *  @brief  %Multimap move assignment operator.
257       *  @param  x  A %multimap of identical element and allocator types.
258       *
259       *  The contents of @a x are moved into this multimap (without copying).
260       *  @a x is a valid, but unspecified multimap.
261       */
262      multimap&
263      operator=(multimap&& __x)
264      {
265	// NB: DR 1204.
266	// NB: DR 675.
267	this->clear();
268	this->swap(__x);
269	return *this;
270      }
271
272      /**
273       *  @brief  %Multimap list assignment operator.
274       *  @param  l  An initializer_list.
275       *
276       *  This function fills a %multimap with copies of the elements
277       *  in the initializer list @a l.
278       *
279       *  Note that the assignment completely changes the %multimap and
280       *  that the resulting %multimap's size is the same as the number
281       *  of elements assigned.  Old data may be lost.
282       */
283      multimap&
284      operator=(initializer_list<value_type> __l)
285      {
286	this->clear();
287	this->insert(__l.begin(), __l.end());
288	return *this;
289      }
290#endif
291
292      /// Get a copy of the memory allocation object.
293      allocator_type
294      get_allocator() const
295      { return _M_t.get_allocator(); }
296
297      // iterators
298      /**
299       *  Returns a read/write iterator that points to the first pair in the
300       *  %multimap.  Iteration is done in ascending order according to the
301       *  keys.
302       */
303      iterator
304      begin()
305      { return _M_t.begin(); }
306
307      /**
308       *  Returns a read-only (constant) iterator that points to the first pair
309       *  in the %multimap.  Iteration is done in ascending order according to
310       *  the keys.
311       */
312      const_iterator
313      begin() const
314      { return _M_t.begin(); }
315
316      /**
317       *  Returns a read/write iterator that points one past the last pair in
318       *  the %multimap.  Iteration is done in ascending order according to the
319       *  keys.
320       */
321      iterator
322      end()
323      { return _M_t.end(); }
324
325      /**
326       *  Returns a read-only (constant) iterator that points one past the last
327       *  pair in the %multimap.  Iteration is done in ascending order according
328       *  to the keys.
329       */
330      const_iterator
331      end() const
332      { return _M_t.end(); }
333
334      /**
335       *  Returns a read/write reverse iterator that points to the last pair in
336       *  the %multimap.  Iteration is done in descending order according to the
337       *  keys.
338       */
339      reverse_iterator
340      rbegin()
341      { return _M_t.rbegin(); }
342
343      /**
344       *  Returns a read-only (constant) reverse iterator that points to the
345       *  last pair in the %multimap.  Iteration is done in descending order
346       *  according to the keys.
347       */
348      const_reverse_iterator
349      rbegin() const
350      { return _M_t.rbegin(); }
351
352      /**
353       *  Returns a read/write reverse iterator that points to one before the
354       *  first pair in the %multimap.  Iteration is done in descending order
355       *  according to the keys.
356       */
357      reverse_iterator
358      rend()
359      { return _M_t.rend(); }
360
361      /**
362       *  Returns a read-only (constant) reverse iterator that points to one
363       *  before the first pair in the %multimap.  Iteration is done in
364       *  descending order according to the keys.
365       */
366      const_reverse_iterator
367      rend() const
368      { return _M_t.rend(); }
369
370#ifdef __GXX_EXPERIMENTAL_CXX0X__
371      /**
372       *  Returns a read-only (constant) iterator that points to the first pair
373       *  in the %multimap.  Iteration is done in ascending order according to
374       *  the keys.
375       */
376      const_iterator
377      cbegin() const
378      { return _M_t.begin(); }
379
380      /**
381       *  Returns a read-only (constant) iterator that points one past the last
382       *  pair in the %multimap.  Iteration is done in ascending order according
383       *  to the keys.
384       */
385      const_iterator
386      cend() const
387      { return _M_t.end(); }
388
389      /**
390       *  Returns a read-only (constant) reverse iterator that points to the
391       *  last pair in the %multimap.  Iteration is done in descending order
392       *  according to the keys.
393       */
394      const_reverse_iterator
395      crbegin() const
396      { return _M_t.rbegin(); }
397
398      /**
399       *  Returns a read-only (constant) reverse iterator that points to one
400       *  before the first pair in the %multimap.  Iteration is done in
401       *  descending order according to the keys.
402       */
403      const_reverse_iterator
404      crend() const
405      { return _M_t.rend(); }
406#endif
407
408      // capacity
409      /** Returns true if the %multimap is empty.  */
410      bool
411      empty() const
412      { return _M_t.empty(); }
413
414      /** Returns the size of the %multimap.  */
415      size_type
416      size() const
417      { return _M_t.size(); }
418
419      /** Returns the maximum size of the %multimap.  */
420      size_type
421      max_size() const
422      { return _M_t.max_size(); }
423
424      // modifiers
425      /**
426       *  @brief Inserts a std::pair into the %multimap.
427       *  @param  x  Pair to be inserted (see std::make_pair for easy creation
428       *             of pairs).
429       *  @return An iterator that points to the inserted (key,value) pair.
430       *
431       *  This function inserts a (key, value) pair into the %multimap.
432       *  Contrary to a std::map the %multimap does not rely on unique keys and
433       *  thus multiple pairs with the same key can be inserted.
434       *
435       *  Insertion requires logarithmic time.
436       */
437      iterator
438      insert(const value_type& __x)
439      { return _M_t._M_insert_equal(__x); }
440
441      /**
442       *  @brief Inserts a std::pair into the %multimap.
443       *  @param  position  An iterator that serves as a hint as to where the
444       *                    pair should be inserted.
445       *  @param  x  Pair to be inserted (see std::make_pair for easy creation
446       *             of pairs).
447       *  @return An iterator that points to the inserted (key,value) pair.
448       *
449       *  This function inserts a (key, value) pair into the %multimap.
450       *  Contrary to a std::map the %multimap does not rely on unique keys and
451       *  thus multiple pairs with the same key can be inserted.
452       *  Note that the first parameter is only a hint and can potentially
453       *  improve the performance of the insertion process.  A bad hint would
454       *  cause no gains in efficiency.
455       *
456       *  For more on @a hinting, see:
457       *  http://gcc.gnu.org/onlinedocs/libstdc++/manual/bk01pt07ch17.html
458       *
459       *  Insertion requires logarithmic time (if the hint is not taken).
460       */
461      iterator
462      insert(iterator __position, const value_type& __x)
463      { return _M_t._M_insert_equal_(__position, __x); }
464
465      /**
466       *  @brief A template function that attempts to insert a range
467       *  of elements.
468       *  @param  first  Iterator pointing to the start of the range to be
469       *                 inserted.
470       *  @param  last  Iterator pointing to the end of the range.
471       *
472       *  Complexity similar to that of the range constructor.
473       */
474      template<typename _InputIterator>
475        void
476        insert(_InputIterator __first, _InputIterator __last)
477        { _M_t._M_insert_equal(__first, __last); }
478
479#ifdef __GXX_EXPERIMENTAL_CXX0X__
480      /**
481       *  @brief Attempts to insert a list of std::pairs into the %multimap.
482       *  @param  list  A std::initializer_list<value_type> of pairs to be
483       *                inserted.
484       *
485       *  Complexity similar to that of the range constructor.
486       */
487      void
488      insert(initializer_list<value_type> __l)
489      { this->insert(__l.begin(), __l.end()); }
490#endif
491
492#ifdef __GXX_EXPERIMENTAL_CXX0X__
493      // _GLIBCXX_RESOLVE_LIB_DEFECTS
494      // DR 130. Associative erase should return an iterator.
495      /**
496       *  @brief Erases an element from a %multimap.
497       *  @param  position  An iterator pointing to the element to be erased.
498       *  @return An iterator pointing to the element immediately following
499       *          @a position prior to the element being erased. If no such
500       *          element exists, end() is returned.
501       *
502       *  This function erases an element, pointed to by the given iterator,
503       *  from a %multimap.  Note that this function only erases the element,
504       *  and that if the element is itself a pointer, the pointed-to memory is
505       *  not touched in any way.  Managing the pointer is the user's
506       *  responsibility.
507       */
508      iterator
509      erase(iterator __position)
510      { return _M_t.erase(__position); }
511#else
512      /**
513       *  @brief Erases an element from a %multimap.
514       *  @param  position  An iterator pointing to the element to be erased.
515       *
516       *  This function erases an element, pointed to by the given iterator,
517       *  from a %multimap.  Note that this function only erases the element,
518       *  and that if the element is itself a pointer, the pointed-to memory is
519       *  not touched in any way.  Managing the pointer is the user's
520       *  responsibility.
521       */
522      void
523      erase(iterator __position)
524      { _M_t.erase(__position); }
525#endif
526
527      /**
528       *  @brief Erases elements according to the provided key.
529       *  @param  x  Key of element to be erased.
530       *  @return  The number of elements erased.
531       *
532       *  This function erases all elements located by the given key from a
533       *  %multimap.
534       *  Note that this function only erases the element, and that if
535       *  the element is itself a pointer, the pointed-to memory is not touched
536       *  in any way.  Managing the pointer is the user's responsibility.
537       */
538      size_type
539      erase(const key_type& __x)
540      { return _M_t.erase(__x); }
541
542#ifdef __GXX_EXPERIMENTAL_CXX0X__
543      // _GLIBCXX_RESOLVE_LIB_DEFECTS
544      // DR 130. Associative erase should return an iterator.
545      /**
546       *  @brief Erases a [first,last) range of elements from a %multimap.
547       *  @param  first  Iterator pointing to the start of the range to be
548       *                 erased.
549       *  @param  last  Iterator pointing to the end of the range to be erased.
550       *  @return The iterator @a last.
551       *
552       *  This function erases a sequence of elements from a %multimap.
553       *  Note that this function only erases the elements, and that if
554       *  the elements themselves are pointers, the pointed-to memory is not
555       *  touched in any way.  Managing the pointer is the user's responsibility.
556       */
557      iterator
558      erase(iterator __first, iterator __last)
559      { return _M_t.erase(__first, __last); }
560#else
561      // _GLIBCXX_RESOLVE_LIB_DEFECTS
562      // DR 130. Associative erase should return an iterator.
563      /**
564       *  @brief Erases a [first,last) range of elements from a %multimap.
565       *  @param  first  Iterator pointing to the start of the range to be
566       *                 erased.
567       *  @param  last  Iterator pointing to the end of the range to be erased.
568       *
569       *  This function erases a sequence of elements from a %multimap.
570       *  Note that this function only erases the elements, and that if
571       *  the elements themselves are pointers, the pointed-to memory is not
572       *  touched in any way.  Managing the pointer is the user's responsibility.
573       */
574      void
575      erase(iterator __first, iterator __last)
576      { _M_t.erase(__first, __last); }
577#endif
578
579      /**
580       *  @brief  Swaps data with another %multimap.
581       *  @param  x  A %multimap of the same element and allocator types.
582       *
583       *  This exchanges the elements between two multimaps in constant time.
584       *  (It is only swapping a pointer, an integer, and an instance of
585       *  the @c Compare type (which itself is often stateless and empty), so it
586       *  should be quite fast.)
587       *  Note that the global std::swap() function is specialized such that
588       *  std::swap(m1,m2) will feed to this function.
589       */
590      void
591      swap(multimap& __x)
592      { _M_t.swap(__x._M_t); }
593
594      /**
595       *  Erases all elements in a %multimap.  Note that this function only
596       *  erases the elements, and that if the elements themselves are pointers,
597       *  the pointed-to memory is not touched in any way.  Managing the pointer
598       *  is the user's responsibility.
599       */
600      void
601      clear()
602      { _M_t.clear(); }
603
604      // observers
605      /**
606       *  Returns the key comparison object out of which the %multimap
607       *  was constructed.
608       */
609      key_compare
610      key_comp() const
611      { return _M_t.key_comp(); }
612
613      /**
614       *  Returns a value comparison object, built from the key comparison
615       *  object out of which the %multimap was constructed.
616       */
617      value_compare
618      value_comp() const
619      { return value_compare(_M_t.key_comp()); }
620
621      // multimap operations
622      /**
623       *  @brief Tries to locate an element in a %multimap.
624       *  @param  x  Key of (key, value) pair to be located.
625       *  @return  Iterator pointing to sought-after element,
626       *           or end() if not found.
627       *
628       *  This function takes a key and tries to locate the element with which
629       *  the key matches.  If successful the function returns an iterator
630       *  pointing to the sought after %pair.  If unsuccessful it returns the
631       *  past-the-end ( @c end() ) iterator.
632       */
633      iterator
634      find(const key_type& __x)
635      { return _M_t.find(__x); }
636
637      /**
638       *  @brief Tries to locate an element in a %multimap.
639       *  @param  x  Key of (key, value) pair to be located.
640       *  @return  Read-only (constant) iterator pointing to sought-after
641       *           element, or end() if not found.
642       *
643       *  This function takes a key and tries to locate the element with which
644       *  the key matches.  If successful the function returns a constant
645       *  iterator pointing to the sought after %pair.  If unsuccessful it
646       *  returns the past-the-end ( @c end() ) iterator.
647       */
648      const_iterator
649      find(const key_type& __x) const
650      { return _M_t.find(__x); }
651
652      /**
653       *  @brief Finds the number of elements with given key.
654       *  @param  x  Key of (key, value) pairs to be located.
655       *  @return Number of elements with specified key.
656       */
657      size_type
658      count(const key_type& __x) const
659      { return _M_t.count(__x); }
660
661      /**
662       *  @brief Finds the beginning of a subsequence matching given key.
663       *  @param  x  Key of (key, value) pair to be located.
664       *  @return  Iterator pointing to first element equal to or greater
665       *           than key, or end().
666       *
667       *  This function returns the first element of a subsequence of elements
668       *  that matches the given key.  If unsuccessful it returns an iterator
669       *  pointing to the first element that has a greater value than given key
670       *  or end() if no such element exists.
671       */
672      iterator
673      lower_bound(const key_type& __x)
674      { return _M_t.lower_bound(__x); }
675
676      /**
677       *  @brief Finds the beginning of a subsequence matching given key.
678       *  @param  x  Key of (key, value) pair to be located.
679       *  @return  Read-only (constant) iterator pointing to first element
680       *           equal to or greater than key, or end().
681       *
682       *  This function returns the first element of a subsequence of elements
683       *  that matches the given key.  If unsuccessful the iterator will point
684       *  to the next greatest element or, if no such greater element exists, to
685       *  end().
686       */
687      const_iterator
688      lower_bound(const key_type& __x) const
689      { return _M_t.lower_bound(__x); }
690
691      /**
692       *  @brief Finds the end of a subsequence matching given key.
693       *  @param  x  Key of (key, value) pair to be located.
694       *  @return Iterator pointing to the first element
695       *          greater than key, or end().
696       */
697      iterator
698      upper_bound(const key_type& __x)
699      { return _M_t.upper_bound(__x); }
700
701      /**
702       *  @brief Finds the end of a subsequence matching given key.
703       *  @param  x  Key of (key, value) pair to be located.
704       *  @return  Read-only (constant) iterator pointing to first iterator
705       *           greater than key, or end().
706       */
707      const_iterator
708      upper_bound(const key_type& __x) const
709      { return _M_t.upper_bound(__x); }
710
711      /**
712       *  @brief Finds a subsequence matching given key.
713       *  @param  x  Key of (key, value) pairs to be located.
714       *  @return  Pair of iterators that possibly points to the subsequence
715       *           matching given key.
716       *
717       *  This function is equivalent to
718       *  @code
719       *    std::make_pair(c.lower_bound(val),
720       *                   c.upper_bound(val))
721       *  @endcode
722       *  (but is faster than making the calls separately).
723       */
724      std::pair<iterator, iterator>
725      equal_range(const key_type& __x)
726      { return _M_t.equal_range(__x); }
727
728      /**
729       *  @brief Finds a subsequence matching given key.
730       *  @param  x  Key of (key, value) pairs to be located.
731       *  @return  Pair of read-only (constant) iterators that possibly points
732       *           to the subsequence matching given key.
733       *
734       *  This function is equivalent to
735       *  @code
736       *    std::make_pair(c.lower_bound(val),
737       *                   c.upper_bound(val))
738       *  @endcode
739       *  (but is faster than making the calls separately).
740       */
741      std::pair<const_iterator, const_iterator>
742      equal_range(const key_type& __x) const
743      { return _M_t.equal_range(__x); }
744
745      template<typename _K1, typename _T1, typename _C1, typename _A1>
746        friend bool
747        operator==(const multimap<_K1, _T1, _C1, _A1>&,
748		   const multimap<_K1, _T1, _C1, _A1>&);
749
750      template<typename _K1, typename _T1, typename _C1, typename _A1>
751        friend bool
752        operator<(const multimap<_K1, _T1, _C1, _A1>&,
753		  const multimap<_K1, _T1, _C1, _A1>&);
754  };
755
756  /**
757   *  @brief  Multimap equality comparison.
758   *  @param  x  A %multimap.
759   *  @param  y  A %multimap of the same type as @a x.
760   *  @return  True iff the size and elements of the maps are equal.
761   *
762   *  This is an equivalence relation.  It is linear in the size of the
763   *  multimaps.  Multimaps are considered equivalent if their sizes are equal,
764   *  and if corresponding elements compare equal.
765  */
766  template<typename _Key, typename _Tp, typename _Compare, typename _Alloc>
767    inline bool
768    operator==(const multimap<_Key, _Tp, _Compare, _Alloc>& __x,
769               const multimap<_Key, _Tp, _Compare, _Alloc>& __y)
770    { return __x._M_t == __y._M_t; }
771
772  /**
773   *  @brief  Multimap ordering relation.
774   *  @param  x  A %multimap.
775   *  @param  y  A %multimap of the same type as @a x.
776   *  @return  True iff @a x is lexicographically less than @a y.
777   *
778   *  This is a total ordering relation.  It is linear in the size of the
779   *  multimaps.  The elements must be comparable with @c <.
780   *
781   *  See std::lexicographical_compare() for how the determination is made.
782  */
783  template<typename _Key, typename _Tp, typename _Compare, typename _Alloc>
784    inline bool
785    operator<(const multimap<_Key, _Tp, _Compare, _Alloc>& __x,
786              const multimap<_Key, _Tp, _Compare, _Alloc>& __y)
787    { return __x._M_t < __y._M_t; }
788
789  /// Based on operator==
790  template<typename _Key, typename _Tp, typename _Compare, typename _Alloc>
791    inline bool
792    operator!=(const multimap<_Key, _Tp, _Compare, _Alloc>& __x,
793               const multimap<_Key, _Tp, _Compare, _Alloc>& __y)
794    { return !(__x == __y); }
795
796  /// Based on operator<
797  template<typename _Key, typename _Tp, typename _Compare, typename _Alloc>
798    inline bool
799    operator>(const multimap<_Key, _Tp, _Compare, _Alloc>& __x,
800              const multimap<_Key, _Tp, _Compare, _Alloc>& __y)
801    { return __y < __x; }
802
803  /// Based on operator<
804  template<typename _Key, typename _Tp, typename _Compare, typename _Alloc>
805    inline bool
806    operator<=(const multimap<_Key, _Tp, _Compare, _Alloc>& __x,
807               const multimap<_Key, _Tp, _Compare, _Alloc>& __y)
808    { return !(__y < __x); }
809
810  /// Based on operator<
811  template<typename _Key, typename _Tp, typename _Compare, typename _Alloc>
812    inline bool
813    operator>=(const multimap<_Key, _Tp, _Compare, _Alloc>& __x,
814               const multimap<_Key, _Tp, _Compare, _Alloc>& __y)
815    { return !(__x < __y); }
816
817  /// See std::multimap::swap().
818  template<typename _Key, typename _Tp, typename _Compare, typename _Alloc>
819    inline void
820    swap(multimap<_Key, _Tp, _Compare, _Alloc>& __x,
821         multimap<_Key, _Tp, _Compare, _Alloc>& __y)
822    { __x.swap(__y); }
823
824_GLIBCXX_END_NESTED_NAMESPACE
825
826#endif /* _STL_MULTIMAP_H */
827