libstdc++
stl_multimap.h
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1 // Multimap implementation -*- C++ -*-
2 
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25 /*
26  *
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49  */
50 
51 /** @file bits/stl_multimap.h
52  * This is an internal header file, included by other library headers.
53  * Do not attempt to use it directly. @headername{map}
54  */
55 
56 #ifndef _STL_MULTIMAP_H
57 #define _STL_MULTIMAP_H 1
58 
59 #include <bits/concept_check.h>
60 #if __cplusplus >= 201103L
61 #include <initializer_list>
62 #endif
63 
64 namespace std _GLIBCXX_VISIBILITY(default)
65 {
66 _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
67 
68  /**
69  * @brief A standard container made up of (key,value) pairs, which can be
70  * retrieved based on a key, in logarithmic time.
71  *
72  * @ingroup associative_containers
73  *
74  * @tparam _Key Type of key objects.
75  * @tparam _Tp Type of mapped objects.
76  * @tparam _Compare Comparison function object type, defaults to less<_Key>.
77  * @tparam _Alloc Allocator type, defaults to
78  * allocator<pair<const _Key, _Tp>.
79  *
80  * Meets the requirements of a <a href="tables.html#65">container</a>, a
81  * <a href="tables.html#66">reversible container</a>, and an
82  * <a href="tables.html#69">associative container</a> (using equivalent
83  * keys). For a @c multimap<Key,T> the key_type is Key, the mapped_type
84  * is T, and the value_type is std::pair<const Key,T>.
85  *
86  * Multimaps support bidirectional iterators.
87  *
88  * The private tree data is declared exactly the same way for map and
89  * multimap; the distinction is made entirely in how the tree functions are
90  * called (*_unique versus *_equal, same as the standard).
91  */
92  template <typename _Key, typename _Tp,
93  typename _Compare = std::less<_Key>,
94  typename _Alloc = std::allocator<std::pair<const _Key, _Tp> > >
95  class multimap
96  {
97  public:
98  typedef _Key key_type;
99  typedef _Tp mapped_type;
101  typedef _Compare key_compare;
102  typedef _Alloc allocator_type;
103 
104  private:
105  // concept requirements
106  typedef typename _Alloc::value_type _Alloc_value_type;
107  __glibcxx_class_requires(_Tp, _SGIAssignableConcept)
108  __glibcxx_class_requires4(_Compare, bool, _Key, _Key,
109  _BinaryFunctionConcept)
110  __glibcxx_class_requires2(value_type, _Alloc_value_type, _SameTypeConcept)
111 
112  public:
113  class value_compare
114  : public std::binary_function<value_type, value_type, bool>
115  {
116  friend class multimap<_Key, _Tp, _Compare, _Alloc>;
117  protected:
118  _Compare comp;
119 
120  value_compare(_Compare __c)
121  : comp(__c) { }
122 
123  public:
124  bool operator()(const value_type& __x, const value_type& __y) const
125  { return comp(__x.first, __y.first); }
126  };
127 
128  private:
129  /// This turns a red-black tree into a [multi]map.
130  typedef typename _Alloc::template rebind<value_type>::other
131  _Pair_alloc_type;
132 
133  typedef _Rb_tree<key_type, value_type, _Select1st<value_type>,
134  key_compare, _Pair_alloc_type> _Rep_type;
135  /// The actual tree structure.
136  _Rep_type _M_t;
137 
138  public:
139  // many of these are specified differently in ISO, but the following are
140  // "functionally equivalent"
141  typedef typename _Pair_alloc_type::pointer pointer;
142  typedef typename _Pair_alloc_type::const_pointer const_pointer;
143  typedef typename _Pair_alloc_type::reference reference;
144  typedef typename _Pair_alloc_type::const_reference const_reference;
145  typedef typename _Rep_type::iterator iterator;
146  typedef typename _Rep_type::const_iterator const_iterator;
147  typedef typename _Rep_type::size_type size_type;
148  typedef typename _Rep_type::difference_type difference_type;
151 
152  // [23.3.2] construct/copy/destroy
153  // (get_allocator() is also listed in this section)
154  /**
155  * @brief Default constructor creates no elements.
156  */
158  : _M_t() { }
159 
160  /**
161  * @brief Creates a %multimap with no elements.
162  * @param __comp A comparison object.
163  * @param __a An allocator object.
164  */
165  explicit
166  multimap(const _Compare& __comp,
167  const allocator_type& __a = allocator_type())
168  : _M_t(__comp, _Pair_alloc_type(__a)) { }
169 
170  /**
171  * @brief %Multimap copy constructor.
172  * @param __x A %multimap of identical element and allocator types.
173  *
174  * The newly-created %multimap uses a copy of the allocation object
175  * used by @a __x.
176  */
177  multimap(const multimap& __x)
178  : _M_t(__x._M_t) { }
179 
180 #if __cplusplus >= 201103L
181  /**
182  * @brief %Multimap move constructor.
183  * @param __x A %multimap of identical element and allocator types.
184  *
185  * The newly-created %multimap contains the exact contents of @a __x.
186  * The contents of @a __x are a valid, but unspecified %multimap.
187  */
189  noexcept(is_nothrow_copy_constructible<_Compare>::value)
190  : _M_t(std::move(__x._M_t)) { }
191 
192  /**
193  * @brief Builds a %multimap from an initializer_list.
194  * @param __l An initializer_list.
195  * @param __comp A comparison functor.
196  * @param __a An allocator object.
197  *
198  * Create a %multimap consisting of copies of the elements from
199  * the initializer_list. This is linear in N if the list is already
200  * sorted, and NlogN otherwise (where N is @a __l.size()).
201  */
203  const _Compare& __comp = _Compare(),
204  const allocator_type& __a = allocator_type())
205  : _M_t(__comp, _Pair_alloc_type(__a))
206  { _M_t._M_insert_equal(__l.begin(), __l.end()); }
207 #endif
208 
209  /**
210  * @brief Builds a %multimap from a range.
211  * @param __first An input iterator.
212  * @param __last An input iterator.
213  *
214  * Create a %multimap consisting of copies of the elements from
215  * [__first,__last). This is linear in N if the range is already sorted,
216  * and NlogN otherwise (where N is distance(__first,__last)).
217  */
218  template<typename _InputIterator>
219  multimap(_InputIterator __first, _InputIterator __last)
220  : _M_t()
221  { _M_t._M_insert_equal(__first, __last); }
222 
223  /**
224  * @brief Builds a %multimap from a range.
225  * @param __first An input iterator.
226  * @param __last An input iterator.
227  * @param __comp A comparison functor.
228  * @param __a An allocator object.
229  *
230  * Create a %multimap consisting of copies of the elements from
231  * [__first,__last). This is linear in N if the range is already sorted,
232  * and NlogN otherwise (where N is distance(__first,__last)).
233  */
234  template<typename _InputIterator>
235  multimap(_InputIterator __first, _InputIterator __last,
236  const _Compare& __comp,
237  const allocator_type& __a = allocator_type())
238  : _M_t(__comp, _Pair_alloc_type(__a))
239  { _M_t._M_insert_equal(__first, __last); }
240 
241  // FIXME There is no dtor declared, but we should have something generated
242  // by Doxygen. I don't know what tags to add to this paragraph to make
243  // that happen:
244  /**
245  * The dtor only erases the elements, and note that if the elements
246  * themselves are pointers, the pointed-to memory is not touched in any
247  * way. Managing the pointer is the user's responsibility.
248  */
249 
250  /**
251  * @brief %Multimap assignment operator.
252  * @param __x A %multimap of identical element and allocator types.
253  *
254  * All the elements of @a __x are copied, but unlike the copy
255  * constructor, the allocator object is not copied.
256  */
257  multimap&
258  operator=(const multimap& __x)
259  {
260  _M_t = __x._M_t;
261  return *this;
262  }
263 
264 #if __cplusplus >= 201103L
265  /**
266  * @brief %Multimap move assignment operator.
267  * @param __x A %multimap of identical element and allocator types.
268  *
269  * The contents of @a __x are moved into this multimap (without copying).
270  * @a __x is a valid, but unspecified multimap.
271  */
272  multimap&
274  {
275  // NB: DR 1204.
276  // NB: DR 675.
277  this->clear();
278  this->swap(__x);
279  return *this;
280  }
281 
282  /**
283  * @brief %Multimap list assignment operator.
284  * @param __l An initializer_list.
285  *
286  * This function fills a %multimap with copies of the elements
287  * in the initializer list @a __l.
288  *
289  * Note that the assignment completely changes the %multimap and
290  * that the resulting %multimap's size is the same as the number
291  * of elements assigned. Old data may be lost.
292  */
293  multimap&
295  {
296  this->clear();
297  this->insert(__l.begin(), __l.end());
298  return *this;
299  }
300 #endif
301 
302  /// Get a copy of the memory allocation object.
303  allocator_type
304  get_allocator() const _GLIBCXX_NOEXCEPT
305  { return allocator_type(_M_t.get_allocator()); }
306 
307  // iterators
308  /**
309  * Returns a read/write iterator that points to the first pair in the
310  * %multimap. Iteration is done in ascending order according to the
311  * keys.
312  */
313  iterator
314  begin() _GLIBCXX_NOEXCEPT
315  { return _M_t.begin(); }
316 
317  /**
318  * Returns a read-only (constant) iterator that points to the first pair
319  * in the %multimap. Iteration is done in ascending order according to
320  * the keys.
321  */
322  const_iterator
323  begin() const _GLIBCXX_NOEXCEPT
324  { return _M_t.begin(); }
325 
326  /**
327  * Returns a read/write iterator that points one past the last pair in
328  * the %multimap. Iteration is done in ascending order according to the
329  * keys.
330  */
331  iterator
332  end() _GLIBCXX_NOEXCEPT
333  { return _M_t.end(); }
334 
335  /**
336  * Returns a read-only (constant) iterator that points one past the last
337  * pair in the %multimap. Iteration is done in ascending order according
338  * to the keys.
339  */
340  const_iterator
341  end() const _GLIBCXX_NOEXCEPT
342  { return _M_t.end(); }
343 
344  /**
345  * Returns a read/write reverse iterator that points to the last pair in
346  * the %multimap. Iteration is done in descending order according to the
347  * keys.
348  */
350  rbegin() _GLIBCXX_NOEXCEPT
351  { return _M_t.rbegin(); }
352 
353  /**
354  * Returns a read-only (constant) reverse iterator that points to the
355  * last pair in the %multimap. Iteration is done in descending order
356  * according to the keys.
357  */
358  const_reverse_iterator
359  rbegin() const _GLIBCXX_NOEXCEPT
360  { return _M_t.rbegin(); }
361 
362  /**
363  * Returns a read/write reverse iterator that points to one before the
364  * first pair in the %multimap. Iteration is done in descending order
365  * according to the keys.
366  */
368  rend() _GLIBCXX_NOEXCEPT
369  { return _M_t.rend(); }
370 
371  /**
372  * Returns a read-only (constant) reverse iterator that points to one
373  * before the first pair in the %multimap. Iteration is done in
374  * descending order according to the keys.
375  */
376  const_reverse_iterator
377  rend() const _GLIBCXX_NOEXCEPT
378  { return _M_t.rend(); }
379 
380 #if __cplusplus >= 201103L
381  /**
382  * Returns a read-only (constant) iterator that points to the first pair
383  * in the %multimap. Iteration is done in ascending order according to
384  * the keys.
385  */
386  const_iterator
387  cbegin() const noexcept
388  { return _M_t.begin(); }
389 
390  /**
391  * Returns a read-only (constant) iterator that points one past the last
392  * pair in the %multimap. Iteration is done in ascending order according
393  * to the keys.
394  */
395  const_iterator
396  cend() const noexcept
397  { return _M_t.end(); }
398 
399  /**
400  * Returns a read-only (constant) reverse iterator that points to the
401  * last pair in the %multimap. Iteration is done in descending order
402  * according to the keys.
403  */
404  const_reverse_iterator
405  crbegin() const noexcept
406  { return _M_t.rbegin(); }
407 
408  /**
409  * Returns a read-only (constant) reverse iterator that points to one
410  * before the first pair in the %multimap. Iteration is done in
411  * descending order according to the keys.
412  */
413  const_reverse_iterator
414  crend() const noexcept
415  { return _M_t.rend(); }
416 #endif
417 
418  // capacity
419  /** Returns true if the %multimap is empty. */
420  bool
421  empty() const _GLIBCXX_NOEXCEPT
422  { return _M_t.empty(); }
423 
424  /** Returns the size of the %multimap. */
425  size_type
426  size() const _GLIBCXX_NOEXCEPT
427  { return _M_t.size(); }
428 
429  /** Returns the maximum size of the %multimap. */
430  size_type
431  max_size() const _GLIBCXX_NOEXCEPT
432  { return _M_t.max_size(); }
433 
434  // modifiers
435 #if __cplusplus >= 201103L
436  /**
437  * @brief Build and insert a std::pair into the %multimap.
438  *
439  * @param __args Arguments used to generate a new pair instance (see
440  * std::piecewise_contruct for passing arguments to each
441  * part of the pair constructor).
442  *
443  * @return An iterator that points to the inserted (key,value) pair.
444  *
445  * This function builds and inserts a (key, value) %pair into the
446  * %multimap.
447  * Contrary to a std::map the %multimap does not rely on unique keys and
448  * thus multiple pairs with the same key can be inserted.
449  *
450  * Insertion requires logarithmic time.
451  */
452  template<typename... _Args>
453  iterator
454  emplace(_Args&&... __args)
455  { return _M_t._M_emplace_equal(std::forward<_Args>(__args)...); }
456 
457  /**
458  * @brief Builds and inserts a std::pair into the %multimap.
459  *
460  * @param __pos An iterator that serves as a hint as to where the pair
461  * should be inserted.
462  * @param __args Arguments used to generate a new pair instance (see
463  * std::piecewise_contruct for passing arguments to each
464  * part of the pair constructor).
465  * @return An iterator that points to the inserted (key,value) pair.
466  *
467  * This function inserts a (key, value) pair into the %multimap.
468  * Contrary to a std::map the %multimap does not rely on unique keys and
469  * thus multiple pairs with the same key can be inserted.
470  * Note that the first parameter is only a hint and can potentially
471  * improve the performance of the insertion process. A bad hint would
472  * cause no gains in efficiency.
473  *
474  * For more on @a hinting, see:
475  * http://gcc.gnu.org/onlinedocs/libstdc++/manual/bk01pt07ch17.html
476  *
477  * Insertion requires logarithmic time (if the hint is not taken).
478  */
479  template<typename... _Args>
480  iterator
481  emplace_hint(const_iterator __pos, _Args&&... __args)
482  {
483  return _M_t._M_emplace_hint_equal(__pos,
484  std::forward<_Args>(__args)...);
485  }
486 #endif
487 
488  /**
489  * @brief Inserts a std::pair into the %multimap.
490  * @param __x Pair to be inserted (see std::make_pair for easy creation
491  * of pairs).
492  * @return An iterator that points to the inserted (key,value) pair.
493  *
494  * This function inserts a (key, value) pair into the %multimap.
495  * Contrary to a std::map the %multimap does not rely on unique keys and
496  * thus multiple pairs with the same key can be inserted.
497  *
498  * Insertion requires logarithmic time.
499  */
500  iterator
501  insert(const value_type& __x)
502  { return _M_t._M_insert_equal(__x); }
503 
504 #if __cplusplus >= 201103L
505  template<typename _Pair, typename = typename
507  _Pair&&>::value>::type>
508  iterator
509  insert(_Pair&& __x)
510  { return _M_t._M_insert_equal(std::forward<_Pair>(__x)); }
511 #endif
512 
513  /**
514  * @brief Inserts a std::pair into the %multimap.
515  * @param __position An iterator that serves as a hint as to where the
516  * pair should be inserted.
517  * @param __x Pair to be inserted (see std::make_pair for easy creation
518  * of pairs).
519  * @return An iterator that points to the inserted (key,value) pair.
520  *
521  * This function inserts a (key, value) pair into the %multimap.
522  * Contrary to a std::map the %multimap does not rely on unique keys and
523  * thus multiple pairs with the same key can be inserted.
524  * Note that the first parameter is only a hint and can potentially
525  * improve the performance of the insertion process. A bad hint would
526  * cause no gains in efficiency.
527  *
528  * For more on @a hinting, see:
529  * http://gcc.gnu.org/onlinedocs/libstdc++/manual/bk01pt07ch17.html
530  *
531  * Insertion requires logarithmic time (if the hint is not taken).
532  */
533  iterator
534 #if __cplusplus >= 201103L
535  insert(const_iterator __position, const value_type& __x)
536 #else
537  insert(iterator __position, const value_type& __x)
538 #endif
539  { return _M_t._M_insert_equal_(__position, __x); }
540 
541 #if __cplusplus >= 201103L
542  template<typename _Pair, typename = typename
544  _Pair&&>::value>::type>
545  iterator
546  insert(const_iterator __position, _Pair&& __x)
547  { return _M_t._M_insert_equal_(__position,
548  std::forward<_Pair>(__x)); }
549 #endif
550 
551  /**
552  * @brief A template function that attempts to insert a range
553  * of elements.
554  * @param __first Iterator pointing to the start of the range to be
555  * inserted.
556  * @param __last Iterator pointing to the end of the range.
557  *
558  * Complexity similar to that of the range constructor.
559  */
560  template<typename _InputIterator>
561  void
562  insert(_InputIterator __first, _InputIterator __last)
563  { _M_t._M_insert_equal(__first, __last); }
564 
565 #if __cplusplus >= 201103L
566  /**
567  * @brief Attempts to insert a list of std::pairs into the %multimap.
568  * @param __l A std::initializer_list<value_type> of pairs to be
569  * inserted.
570  *
571  * Complexity similar to that of the range constructor.
572  */
573  void
575  { this->insert(__l.begin(), __l.end()); }
576 #endif
577 
578 #if __cplusplus >= 201103L
579  // _GLIBCXX_RESOLVE_LIB_DEFECTS
580  // DR 130. Associative erase should return an iterator.
581  /**
582  * @brief Erases an element from a %multimap.
583  * @param __position An iterator pointing to the element to be erased.
584  * @return An iterator pointing to the element immediately following
585  * @a position prior to the element being erased. If no such
586  * element exists, end() is returned.
587  *
588  * This function erases an element, pointed to by the given iterator,
589  * from a %multimap. Note that this function only erases the element,
590  * and that if the element is itself a pointer, the pointed-to memory is
591  * not touched in any way. Managing the pointer is the user's
592  * responsibility.
593  */
594  iterator
595  erase(const_iterator __position)
596  { return _M_t.erase(__position); }
597 
598  // LWG 2059.
599  iterator
600  erase(iterator __position)
601  { return _M_t.erase(__position); }
602 #else
603  /**
604  * @brief Erases an element from a %multimap.
605  * @param __position An iterator pointing to the element to be erased.
606  *
607  * This function erases an element, pointed to by the given iterator,
608  * from a %multimap. Note that this function only erases the element,
609  * and that if the element is itself a pointer, the pointed-to memory is
610  * not touched in any way. Managing the pointer is the user's
611  * responsibility.
612  */
613  void
614  erase(iterator __position)
615  { _M_t.erase(__position); }
616 #endif
617 
618  /**
619  * @brief Erases elements according to the provided key.
620  * @param __x Key of element to be erased.
621  * @return The number of elements erased.
622  *
623  * This function erases all elements located by the given key from a
624  * %multimap.
625  * Note that this function only erases the element, and that if
626  * the element is itself a pointer, the pointed-to memory is not touched
627  * in any way. Managing the pointer is the user's responsibility.
628  */
629  size_type
630  erase(const key_type& __x)
631  { return _M_t.erase(__x); }
632 
633 #if __cplusplus >= 201103L
634  // _GLIBCXX_RESOLVE_LIB_DEFECTS
635  // DR 130. Associative erase should return an iterator.
636  /**
637  * @brief Erases a [first,last) range of elements from a %multimap.
638  * @param __first Iterator pointing to the start of the range to be
639  * erased.
640  * @param __last Iterator pointing to the end of the range to be
641  * erased .
642  * @return The iterator @a __last.
643  *
644  * This function erases a sequence of elements from a %multimap.
645  * Note that this function only erases the elements, and that if
646  * the elements themselves are pointers, the pointed-to memory is not
647  * touched in any way. Managing the pointer is the user's
648  * responsibility.
649  */
650  iterator
651  erase(const_iterator __first, const_iterator __last)
652  { return _M_t.erase(__first, __last); }
653 #else
654  // _GLIBCXX_RESOLVE_LIB_DEFECTS
655  // DR 130. Associative erase should return an iterator.
656  /**
657  * @brief Erases a [first,last) range of elements from a %multimap.
658  * @param __first Iterator pointing to the start of the range to be
659  * erased.
660  * @param __last Iterator pointing to the end of the range to
661  * be erased.
662  *
663  * This function erases a sequence of elements from a %multimap.
664  * Note that this function only erases the elements, and that if
665  * the elements themselves are pointers, the pointed-to memory is not
666  * touched in any way. Managing the pointer is the user's
667  * responsibility.
668  */
669  void
670  erase(iterator __first, iterator __last)
671  { _M_t.erase(__first, __last); }
672 #endif
673 
674  /**
675  * @brief Swaps data with another %multimap.
676  * @param __x A %multimap of the same element and allocator types.
677  *
678  * This exchanges the elements between two multimaps in constant time.
679  * (It is only swapping a pointer, an integer, and an instance of
680  * the @c Compare type (which itself is often stateless and empty), so it
681  * should be quite fast.)
682  * Note that the global std::swap() function is specialized such that
683  * std::swap(m1,m2) will feed to this function.
684  */
685  void
687  { _M_t.swap(__x._M_t); }
688 
689  /**
690  * Erases all elements in a %multimap. Note that this function only
691  * erases the elements, and that if the elements themselves are pointers,
692  * the pointed-to memory is not touched in any way. Managing the pointer
693  * is the user's responsibility.
694  */
695  void
696  clear() _GLIBCXX_NOEXCEPT
697  { _M_t.clear(); }
698 
699  // observers
700  /**
701  * Returns the key comparison object out of which the %multimap
702  * was constructed.
703  */
704  key_compare
705  key_comp() const
706  { return _M_t.key_comp(); }
707 
708  /**
709  * Returns a value comparison object, built from the key comparison
710  * object out of which the %multimap was constructed.
711  */
712  value_compare
713  value_comp() const
714  { return value_compare(_M_t.key_comp()); }
715 
716  // multimap operations
717  /**
718  * @brief Tries to locate an element in a %multimap.
719  * @param __x Key of (key, value) pair to be located.
720  * @return Iterator pointing to sought-after element,
721  * or end() if not found.
722  *
723  * This function takes a key and tries to locate the element with which
724  * the key matches. If successful the function returns an iterator
725  * pointing to the sought after %pair. If unsuccessful it returns the
726  * past-the-end ( @c end() ) iterator.
727  */
728  iterator
729  find(const key_type& __x)
730  { return _M_t.find(__x); }
731 
732  /**
733  * @brief Tries to locate an element in a %multimap.
734  * @param __x Key of (key, value) pair to be located.
735  * @return Read-only (constant) iterator pointing to sought-after
736  * element, or end() if not found.
737  *
738  * This function takes a key and tries to locate the element with which
739  * the key matches. If successful the function returns a constant
740  * iterator pointing to the sought after %pair. If unsuccessful it
741  * returns the past-the-end ( @c end() ) iterator.
742  */
743  const_iterator
744  find(const key_type& __x) const
745  { return _M_t.find(__x); }
746 
747  /**
748  * @brief Finds the number of elements with given key.
749  * @param __x Key of (key, value) pairs to be located.
750  * @return Number of elements with specified key.
751  */
752  size_type
753  count(const key_type& __x) const
754  { return _M_t.count(__x); }
755 
756  /**
757  * @brief Finds the beginning of a subsequence matching given key.
758  * @param __x Key of (key, value) pair to be located.
759  * @return Iterator pointing to first element equal to or greater
760  * than key, or end().
761  *
762  * This function returns the first element of a subsequence of elements
763  * that matches the given key. If unsuccessful it returns an iterator
764  * pointing to the first element that has a greater value than given key
765  * or end() if no such element exists.
766  */
767  iterator
768  lower_bound(const key_type& __x)
769  { return _M_t.lower_bound(__x); }
770 
771  /**
772  * @brief Finds the beginning of a subsequence matching given key.
773  * @param __x Key of (key, value) pair to be located.
774  * @return Read-only (constant) iterator pointing to first element
775  * equal to or greater than key, or end().
776  *
777  * This function returns the first element of a subsequence of
778  * elements that matches the given key. If unsuccessful the
779  * iterator will point to the next greatest element or, if no
780  * such greater element exists, to end().
781  */
782  const_iterator
783  lower_bound(const key_type& __x) const
784  { return _M_t.lower_bound(__x); }
785 
786  /**
787  * @brief Finds the end of a subsequence matching given key.
788  * @param __x Key of (key, value) pair to be located.
789  * @return Iterator pointing to the first element
790  * greater than key, or end().
791  */
792  iterator
793  upper_bound(const key_type& __x)
794  { return _M_t.upper_bound(__x); }
795 
796  /**
797  * @brief Finds the end of a subsequence matching given key.
798  * @param __x Key of (key, value) pair to be located.
799  * @return Read-only (constant) iterator pointing to first iterator
800  * greater than key, or end().
801  */
802  const_iterator
803  upper_bound(const key_type& __x) const
804  { return _M_t.upper_bound(__x); }
805 
806  /**
807  * @brief Finds a subsequence matching given key.
808  * @param __x Key of (key, value) pairs to be located.
809  * @return Pair of iterators that possibly points to the subsequence
810  * matching given key.
811  *
812  * This function is equivalent to
813  * @code
814  * std::make_pair(c.lower_bound(val),
815  * c.upper_bound(val))
816  * @endcode
817  * (but is faster than making the calls separately).
818  */
820  equal_range(const key_type& __x)
821  { return _M_t.equal_range(__x); }
822 
823  /**
824  * @brief Finds a subsequence matching given key.
825  * @param __x Key of (key, value) pairs to be located.
826  * @return Pair of read-only (constant) iterators that possibly points
827  * to the subsequence matching given key.
828  *
829  * This function is equivalent to
830  * @code
831  * std::make_pair(c.lower_bound(val),
832  * c.upper_bound(val))
833  * @endcode
834  * (but is faster than making the calls separately).
835  */
837  equal_range(const key_type& __x) const
838  { return _M_t.equal_range(__x); }
839 
840  template<typename _K1, typename _T1, typename _C1, typename _A1>
841  friend bool
842  operator==(const multimap<_K1, _T1, _C1, _A1>&,
844 
845  template<typename _K1, typename _T1, typename _C1, typename _A1>
846  friend bool
847  operator<(const multimap<_K1, _T1, _C1, _A1>&,
849  };
850 
851  /**
852  * @brief Multimap equality comparison.
853  * @param __x A %multimap.
854  * @param __y A %multimap of the same type as @a __x.
855  * @return True iff the size and elements of the maps are equal.
856  *
857  * This is an equivalence relation. It is linear in the size of the
858  * multimaps. Multimaps are considered equivalent if their sizes are equal,
859  * and if corresponding elements compare equal.
860  */
861  template<typename _Key, typename _Tp, typename _Compare, typename _Alloc>
862  inline bool
865  { return __x._M_t == __y._M_t; }
866 
867  /**
868  * @brief Multimap ordering relation.
869  * @param __x A %multimap.
870  * @param __y A %multimap of the same type as @a __x.
871  * @return True iff @a x is lexicographically less than @a y.
872  *
873  * This is a total ordering relation. It is linear in the size of the
874  * multimaps. The elements must be comparable with @c <.
875  *
876  * See std::lexicographical_compare() for how the determination is made.
877  */
878  template<typename _Key, typename _Tp, typename _Compare, typename _Alloc>
879  inline bool
880  operator<(const multimap<_Key, _Tp, _Compare, _Alloc>& __x,
882  { return __x._M_t < __y._M_t; }
883 
884  /// Based on operator==
885  template<typename _Key, typename _Tp, typename _Compare, typename _Alloc>
886  inline bool
889  { return !(__x == __y); }
890 
891  /// Based on operator<
892  template<typename _Key, typename _Tp, typename _Compare, typename _Alloc>
893  inline bool
896  { return __y < __x; }
897 
898  /// Based on operator<
899  template<typename _Key, typename _Tp, typename _Compare, typename _Alloc>
900  inline bool
901  operator<=(const multimap<_Key, _Tp, _Compare, _Alloc>& __x,
903  { return !(__y < __x); }
904 
905  /// Based on operator<
906  template<typename _Key, typename _Tp, typename _Compare, typename _Alloc>
907  inline bool
910  { return !(__x < __y); }
911 
912  /// See std::multimap::swap().
913  template<typename _Key, typename _Tp, typename _Compare, typename _Alloc>
914  inline void
917  { __x.swap(__y); }
918 
919 _GLIBCXX_END_NAMESPACE_CONTAINER
920 } // namespace std
921 
922 #endif /* _STL_MULTIMAP_H */