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1// Map 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_map.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_MAP_H
58#define _STL_MAP_H 1
59
60#include <bits/functexcept.h>
61#include <bits/concept_check.h>
62#include <initializer_list>
63
64_GLIBCXX_BEGIN_NESTED_NAMESPACE(std, _GLIBCXX_STD_D)
65
66  /**
67   *  @brief A standard container made up of (key,value) pairs, which can be
68   *  retrieved based on a key, in logarithmic time.
69   *
70   *  @ingroup associative_containers
71   *
72   *  Meets the requirements of a <a href="tables.html#65">container</a>, a
73   *  <a href="tables.html#66">reversible container</a>, and an
74   *  <a href="tables.html#69">associative container</a> (using unique keys).
75   *  For a @c map<Key,T> the key_type is Key, the mapped_type is T, and the
76   *  value_type is std::pair<const Key,T>.
77   *
78   *  Maps support bidirectional iterators.
79   *
80   *  The private tree data is declared exactly the same way for map and
81   *  multimap; the distinction is made entirely in how the tree functions are
82   *  called (*_unique versus *_equal, same as the standard).
83  */
84  template <typename _Key, typename _Tp, typename _Compare = std::less<_Key>,
85            typename _Alloc = std::allocator<std::pair<const _Key, _Tp> > >
86    class map
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 map<_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
127      /// The actual tree structure.
128      _Rep_type _M_t;
129
130    public:
131      // many of these are specified differently in ISO, but the following are
132      // "functionally equivalent"
133      typedef typename _Pair_alloc_type::pointer         pointer;
134      typedef typename _Pair_alloc_type::const_pointer   const_pointer;
135      typedef typename _Pair_alloc_type::reference       reference;
136      typedef typename _Pair_alloc_type::const_reference const_reference;
137      typedef typename _Rep_type::iterator               iterator;
138      typedef typename _Rep_type::const_iterator         const_iterator;
139      typedef typename _Rep_type::size_type              size_type;
140      typedef typename _Rep_type::difference_type        difference_type;
141      typedef typename _Rep_type::reverse_iterator       reverse_iterator;
142      typedef typename _Rep_type::const_reverse_iterator const_reverse_iterator;
143
144      // [23.3.1.1] construct/copy/destroy
145      // (get_allocator() is normally listed in this section, but seems to have
146      // been accidentally omitted in the printed standard)
147      /**
148       *  @brief  Default constructor creates no elements.
149       */
150      map()
151      : _M_t() { }
152
153      /**
154       *  @brief  Creates a %map with no elements.
155       *  @param  comp  A comparison object.
156       *  @param  a  An allocator object.
157       */
158      explicit
159      map(const _Compare& __comp,
160	  const allocator_type& __a = allocator_type())
161      : _M_t(__comp, __a) { }
162
163      /**
164       *  @brief  %Map copy constructor.
165       *  @param  x  A %map of identical element and allocator types.
166       *
167       *  The newly-created %map uses a copy of the allocation object
168       *  used by @a x.
169       */
170      map(const map& __x)
171      : _M_t(__x._M_t) { }
172
173#ifdef __GXX_EXPERIMENTAL_CXX0X__
174      /**
175       *  @brief  %Map move constructor.
176       *  @param  x  A %map of identical element and allocator types.
177       *
178       *  The newly-created %map contains the exact contents of @a x.
179       *  The contents of @a x are a valid, but unspecified %map.
180       */
181      map(map&& __x)
182      : _M_t(std::forward<_Rep_type>(__x._M_t)) { }
183
184      /**
185       *  @brief  Builds a %map from an initializer_list.
186       *  @param  l  An initializer_list.
187       *  @param  comp  A comparison object.
188       *  @param  a  An allocator object.
189       *
190       *  Create a %map consisting of copies of the elements in the
191       *  initializer_list @a l.
192       *  This is linear in N if the range is already sorted, and NlogN
193       *  otherwise (where N is @a l.size()).
194       */
195      map(initializer_list<value_type> __l,
196	  const _Compare& __c = _Compare(),
197	  const allocator_type& __a = allocator_type())
198      : _M_t(__c, __a)
199      { _M_t._M_insert_unique(__l.begin(), __l.end()); }
200#endif
201
202      /**
203       *  @brief  Builds a %map from a range.
204       *  @param  first  An input iterator.
205       *  @param  last  An input iterator.
206       *
207       *  Create a %map consisting of copies of the elements from [first,last).
208       *  This is linear in N if the range is already sorted, and NlogN
209       *  otherwise (where N is distance(first,last)).
210       */
211      template<typename _InputIterator>
212        map(_InputIterator __first, _InputIterator __last)
213	: _M_t()
214        { _M_t._M_insert_unique(__first, __last); }
215
216      /**
217       *  @brief  Builds a %map from a range.
218       *  @param  first  An input iterator.
219       *  @param  last  An input iterator.
220       *  @param  comp  A comparison functor.
221       *  @param  a  An allocator object.
222       *
223       *  Create a %map consisting of copies of the elements from [first,last).
224       *  This is linear in N if the range is already sorted, and NlogN
225       *  otherwise (where N is distance(first,last)).
226       */
227      template<typename _InputIterator>
228        map(_InputIterator __first, _InputIterator __last,
229	    const _Compare& __comp,
230	    const allocator_type& __a = allocator_type())
231	: _M_t(__comp, __a)
232        { _M_t._M_insert_unique(__first, __last); }
233
234      // FIXME There is no dtor declared, but we should have something
235      // generated by Doxygen.  I don't know what tags to add to this
236      // paragraph to make that happen:
237      /**
238       *  The dtor only erases the elements, and note that if the elements
239       *  themselves are pointers, the pointed-to memory is not touched in any
240       *  way.  Managing the pointer is the user's responsibility.
241       */
242
243      /**
244       *  @brief  %Map assignment operator.
245       *  @param  x  A %map of identical element and allocator types.
246       *
247       *  All the elements of @a x are copied, but unlike the copy constructor,
248       *  the allocator object is not copied.
249       */
250      map&
251      operator=(const map& __x)
252      {
253	_M_t = __x._M_t;
254	return *this;
255      }
256
257#ifdef __GXX_EXPERIMENTAL_CXX0X__
258      /**
259       *  @brief  %Map move assignment operator.
260       *  @param  x  A %map of identical element and allocator types.
261       *
262       *  The contents of @a x are moved into this map (without copying).
263       *  @a x is a valid, but unspecified %map.
264       */
265      map&
266      operator=(map&& __x)
267      {
268	// NB: DR 1204.
269	// NB: DR 675.
270	this->clear();
271	this->swap(__x);
272	return *this;
273      }
274
275      /**
276       *  @brief  %Map list assignment operator.
277       *  @param  l  An initializer_list.
278       *
279       *  This function fills a %map with copies of the elements in the
280       *  initializer list @a l.
281       *
282       *  Note that the assignment completely changes the %map and
283       *  that the resulting %map's size is the same as the number
284       *  of elements assigned.  Old data may be lost.
285       */
286      map&
287      operator=(initializer_list<value_type> __l)
288      {
289	this->clear();
290	this->insert(__l.begin(), __l.end());
291	return *this;
292      }
293#endif
294
295      /// Get a copy of the memory allocation object.
296      allocator_type
297      get_allocator() const
298      { return _M_t.get_allocator(); }
299
300      // iterators
301      /**
302       *  Returns a read/write iterator that points to the first pair in the
303       *  %map.
304       *  Iteration is done in ascending order according to the keys.
305       */
306      iterator
307      begin()
308      { return _M_t.begin(); }
309
310      /**
311       *  Returns a read-only (constant) iterator that points to the first pair
312       *  in the %map.  Iteration is done in ascending order according to the
313       *  keys.
314       */
315      const_iterator
316      begin() const
317      { return _M_t.begin(); }
318
319      /**
320       *  Returns a read/write iterator that points one past the last
321       *  pair in the %map.  Iteration is done in ascending order
322       *  according to the keys.
323       */
324      iterator
325      end()
326      { return _M_t.end(); }
327
328      /**
329       *  Returns a read-only (constant) iterator that points one past the last
330       *  pair in the %map.  Iteration is done in ascending order according to
331       *  the keys.
332       */
333      const_iterator
334      end() const
335      { return _M_t.end(); }
336
337      /**
338       *  Returns a read/write reverse iterator that points to the last pair in
339       *  the %map.  Iteration is done in descending order according to the
340       *  keys.
341       */
342      reverse_iterator
343      rbegin()
344      { return _M_t.rbegin(); }
345
346      /**
347       *  Returns a read-only (constant) reverse iterator that points to the
348       *  last pair in the %map.  Iteration is done in descending order
349       *  according to the keys.
350       */
351      const_reverse_iterator
352      rbegin() const
353      { return _M_t.rbegin(); }
354
355      /**
356       *  Returns a read/write reverse iterator that points to one before the
357       *  first pair in the %map.  Iteration is done in descending order
358       *  according to the keys.
359       */
360      reverse_iterator
361      rend()
362      { return _M_t.rend(); }
363
364      /**
365       *  Returns a read-only (constant) reverse iterator that points to one
366       *  before the first pair in the %map.  Iteration is done in descending
367       *  order according to the keys.
368       */
369      const_reverse_iterator
370      rend() const
371      { return _M_t.rend(); }
372
373#ifdef __GXX_EXPERIMENTAL_CXX0X__
374      /**
375       *  Returns a read-only (constant) iterator that points to the first pair
376       *  in the %map.  Iteration is done in ascending order according to the
377       *  keys.
378       */
379      const_iterator
380      cbegin() const
381      { return _M_t.begin(); }
382
383      /**
384       *  Returns a read-only (constant) iterator that points one past the last
385       *  pair in the %map.  Iteration is done in ascending order according to
386       *  the keys.
387       */
388      const_iterator
389      cend() const
390      { return _M_t.end(); }
391
392      /**
393       *  Returns a read-only (constant) reverse iterator that points to the
394       *  last pair in the %map.  Iteration is done in descending order
395       *  according to the keys.
396       */
397      const_reverse_iterator
398      crbegin() const
399      { return _M_t.rbegin(); }
400
401      /**
402       *  Returns a read-only (constant) reverse iterator that points to one
403       *  before the first pair in the %map.  Iteration is done in descending
404       *  order according to the keys.
405       */
406      const_reverse_iterator
407      crend() const
408      { return _M_t.rend(); }
409#endif
410
411      // capacity
412      /** Returns true if the %map is empty.  (Thus begin() would equal
413       *  end().)
414      */
415      bool
416      empty() const
417      { return _M_t.empty(); }
418
419      /** Returns the size of the %map.  */
420      size_type
421      size() const
422      { return _M_t.size(); }
423
424      /** Returns the maximum size of the %map.  */
425      size_type
426      max_size() const
427      { return _M_t.max_size(); }
428
429      // [23.3.1.2] element access
430      /**
431       *  @brief  Subscript ( @c [] ) access to %map data.
432       *  @param  k  The key for which data should be retrieved.
433       *  @return  A reference to the data of the (key,data) %pair.
434       *
435       *  Allows for easy lookup with the subscript ( @c [] )
436       *  operator.  Returns data associated with the key specified in
437       *  subscript.  If the key does not exist, a pair with that key
438       *  is created using default values, which is then returned.
439       *
440       *  Lookup requires logarithmic time.
441       */
442      mapped_type&
443      operator[](const key_type& __k)
444      {
445	// concept requirements
446	__glibcxx_function_requires(_DefaultConstructibleConcept<mapped_type>)
447
448	iterator __i = lower_bound(__k);
449	// __i->first is greater than or equivalent to __k.
450	if (__i == end() || key_comp()(__k, (*__i).first))
451          __i = insert(__i, value_type(__k, mapped_type()));
452	return (*__i).second;
453      }
454
455      // _GLIBCXX_RESOLVE_LIB_DEFECTS
456      // DR 464. Suggestion for new member functions in standard containers.
457      /**
458       *  @brief  Access to %map data.
459       *  @param  k  The key for which data should be retrieved.
460       *  @return  A reference to the data whose key is equivalent to @a k, if
461       *           such a data is present in the %map.
462       *  @throw  std::out_of_range  If no such data is present.
463       */
464      mapped_type&
465      at(const key_type& __k)
466      {
467	iterator __i = lower_bound(__k);
468	if (__i == end() || key_comp()(__k, (*__i).first))
469	  __throw_out_of_range(__N("map::at"));
470	return (*__i).second;
471      }
472
473      const mapped_type&
474      at(const key_type& __k) const
475      {
476	const_iterator __i = lower_bound(__k);
477	if (__i == end() || key_comp()(__k, (*__i).first))
478	  __throw_out_of_range(__N("map::at"));
479	return (*__i).second;
480      }
481
482      // modifiers
483      /**
484       *  @brief Attempts to insert a std::pair into the %map.
485
486       *  @param  x  Pair to be inserted (see std::make_pair for easy creation
487       *	     of pairs).
488
489       *  @return  A pair, of which the first element is an iterator that
490       *           points to the possibly inserted pair, and the second is
491       *           a bool that is true if the pair was actually inserted.
492       *
493       *  This function attempts to insert a (key, value) %pair into the %map.
494       *  A %map relies on unique keys and thus a %pair is only inserted if its
495       *  first element (the key) is not already present in the %map.
496       *
497       *  Insertion requires logarithmic time.
498       */
499      std::pair<iterator, bool>
500      insert(const value_type& __x)
501      { return _M_t._M_insert_unique(__x); }
502
503#ifdef __GXX_EXPERIMENTAL_CXX0X__
504      /**
505       *  @brief Attempts to insert a list of std::pairs into the %map.
506       *  @param  list  A std::initializer_list<value_type> of pairs to be
507       *                inserted.
508       *
509       *  Complexity similar to that of the range constructor.
510       */
511      void
512      insert(std::initializer_list<value_type> __list)
513      { insert (__list.begin(), __list.end()); }
514#endif
515
516      /**
517       *  @brief Attempts to insert a std::pair into the %map.
518       *  @param  position  An iterator that serves as a hint as to where the
519       *                    pair should be inserted.
520       *  @param  x  Pair to be inserted (see std::make_pair for easy creation
521       *             of pairs).
522       *  @return  An iterator that points to the element with key of @a x (may
523       *           or may not be the %pair passed in).
524       *
525
526       *  This function is not concerned about whether the insertion
527       *  took place, and thus does not return a boolean like the
528       *  single-argument insert() does.  Note that the first
529       *  parameter is only a hint and can potentially improve the
530       *  performance of the insertion process.  A bad hint would
531       *  cause no gains in efficiency.
532       *
533       *  See
534       *  http://gcc.gnu.org/onlinedocs/libstdc++/manual/bk01pt07ch17.html
535       *  for more on @a hinting.
536       *
537       *  Insertion requires logarithmic time (if the hint is not taken).
538       */
539      iterator
540      insert(iterator __position, const value_type& __x)
541      { return _M_t._M_insert_unique_(__position, __x); }
542
543      /**
544       *  @brief Template function that attempts to insert a range of elements.
545       *  @param  first  Iterator pointing to the start of the range to be
546       *                 inserted.
547       *  @param  last  Iterator pointing to the end of the range.
548       *
549       *  Complexity similar to that of the range constructor.
550       */
551      template<typename _InputIterator>
552        void
553        insert(_InputIterator __first, _InputIterator __last)
554        { _M_t._M_insert_unique(__first, __last); }
555
556#ifdef __GXX_EXPERIMENTAL_CXX0X__
557      // _GLIBCXX_RESOLVE_LIB_DEFECTS
558      // DR 130. Associative erase should return an iterator.
559      /**
560       *  @brief Erases an element from a %map.
561       *  @param  position  An iterator pointing to the element to be erased.
562       *  @return An iterator pointing to the element immediately following
563       *          @a position prior to the element being erased. If no such
564       *          element exists, end() is returned.
565       *
566       *  This function erases an element, pointed to by the given
567       *  iterator, from a %map.  Note that this function only erases
568       *  the element, and that if the element is itself a pointer,
569       *  the pointed-to memory is not touched in any way.  Managing
570       *  the pointer is the user's responsibility.
571       */
572      iterator
573      erase(iterator __position)
574      { return _M_t.erase(__position); }
575#else
576      /**
577       *  @brief Erases an element from a %map.
578       *  @param  position  An iterator pointing to the element to be erased.
579       *
580       *  This function erases an element, pointed to by the given
581       *  iterator, from a %map.  Note that this function only erases
582       *  the element, and that if the element is itself a pointer,
583       *  the pointed-to memory is not touched in any way.  Managing
584       *  the pointer is the user's responsibility.
585       */
586      void
587      erase(iterator __position)
588      { _M_t.erase(__position); }
589#endif
590
591      /**
592       *  @brief Erases elements according to the provided key.
593       *  @param  x  Key of element to be erased.
594       *  @return  The number of elements erased.
595       *
596       *  This function erases all the elements located by the given key from
597       *  a %map.
598       *  Note that this function only erases the element, and that if
599       *  the element is itself a pointer, the pointed-to memory is not touched
600       *  in any way.  Managing the pointer is the user's responsibility.
601       */
602      size_type
603      erase(const key_type& __x)
604      { return _M_t.erase(__x); }
605
606#ifdef __GXX_EXPERIMENTAL_CXX0X__
607      // _GLIBCXX_RESOLVE_LIB_DEFECTS
608      // DR 130. Associative erase should return an iterator.
609      /**
610       *  @brief Erases a [first,last) range of elements from a %map.
611       *  @param  first  Iterator pointing to the start of the range to be
612       *                 erased.
613       *  @param  last  Iterator pointing to the end of the range to be erased.
614       *  @return The iterator @a last.
615       *
616       *  This function erases a sequence of elements from a %map.
617       *  Note that this function only erases the element, and that if
618       *  the element is itself a pointer, the pointed-to memory is not touched
619       *  in any way.  Managing the pointer is the user's responsibility.
620       */
621      iterator
622      erase(iterator __first, iterator __last)
623      { return _M_t.erase(__first, __last); }
624#else
625      /**
626       *  @brief Erases a [first,last) range of elements from a %map.
627       *  @param  first  Iterator pointing to the start of the range to be
628       *                 erased.
629       *  @param  last  Iterator pointing to the end of the range to be erased.
630       *
631       *  This function erases a sequence of elements from a %map.
632       *  Note that this function only erases the element, and that if
633       *  the element is itself a pointer, the pointed-to memory is not touched
634       *  in any way.  Managing the pointer is the user's responsibility.
635       */
636      void
637      erase(iterator __first, iterator __last)
638      { _M_t.erase(__first, __last); }
639#endif
640
641      /**
642       *  @brief  Swaps data with another %map.
643       *  @param  x  A %map of the same element and allocator types.
644       *
645       *  This exchanges the elements between two maps in constant
646       *  time.  (It is only swapping a pointer, an integer, and an
647       *  instance of the @c Compare type (which itself is often
648       *  stateless and empty), so it should be quite fast.)  Note
649       *  that the global std::swap() function is specialized such
650       *  that std::swap(m1,m2) will feed to this function.
651       */
652      void
653      swap(map& __x)
654      { _M_t.swap(__x._M_t); }
655
656      /**
657       *  Erases all elements in a %map.  Note that this function only
658       *  erases the elements, and that if the elements themselves are
659       *  pointers, the pointed-to memory is not touched in any way.
660       *  Managing the pointer is the user's responsibility.
661       */
662      void
663      clear()
664      { _M_t.clear(); }
665
666      // observers
667      /**
668       *  Returns the key comparison object out of which the %map was
669       *  constructed.
670       */
671      key_compare
672      key_comp() const
673      { return _M_t.key_comp(); }
674
675      /**
676       *  Returns a value comparison object, built from the key comparison
677       *  object out of which the %map was constructed.
678       */
679      value_compare
680      value_comp() const
681      { return value_compare(_M_t.key_comp()); }
682
683      // [23.3.1.3] map operations
684      /**
685       *  @brief Tries to locate an element in a %map.
686       *  @param  x  Key of (key, value) %pair to be located.
687       *  @return  Iterator pointing to sought-after element, or end() if not
688       *           found.
689       *
690       *  This function takes a key and tries to locate the element with which
691       *  the key matches.  If successful the function returns an iterator
692       *  pointing to the sought after %pair.  If unsuccessful it returns the
693       *  past-the-end ( @c end() ) iterator.
694       */
695      iterator
696      find(const key_type& __x)
697      { return _M_t.find(__x); }
698
699      /**
700       *  @brief Tries to locate an element in a %map.
701       *  @param  x  Key of (key, value) %pair to be located.
702       *  @return  Read-only (constant) iterator pointing to sought-after
703       *           element, or end() if not found.
704       *
705       *  This function takes a key and tries to locate the element with which
706       *  the key matches.  If successful the function returns a constant
707       *  iterator pointing to the sought after %pair. If unsuccessful it
708       *  returns the past-the-end ( @c end() ) iterator.
709       */
710      const_iterator
711      find(const key_type& __x) const
712      { return _M_t.find(__x); }
713
714      /**
715       *  @brief  Finds the number of elements with given key.
716       *  @param  x  Key of (key, value) pairs to be located.
717       *  @return  Number of elements with specified key.
718       *
719       *  This function only makes sense for multimaps; for map the result will
720       *  either be 0 (not present) or 1 (present).
721       */
722      size_type
723      count(const key_type& __x) const
724      { return _M_t.find(__x) == _M_t.end() ? 0 : 1; }
725
726      /**
727       *  @brief Finds the beginning of a subsequence matching given key.
728       *  @param  x  Key of (key, value) pair to be located.
729       *  @return  Iterator pointing to first element equal to or greater
730       *           than key, or end().
731       *
732       *  This function returns the first element of a subsequence of elements
733       *  that matches the given key.  If unsuccessful it returns an iterator
734       *  pointing to the first element that has a greater value than given key
735       *  or end() if no such element exists.
736       */
737      iterator
738      lower_bound(const key_type& __x)
739      { return _M_t.lower_bound(__x); }
740
741      /**
742       *  @brief Finds the beginning of a subsequence matching given key.
743       *  @param  x  Key of (key, value) pair to be located.
744       *  @return  Read-only (constant) iterator pointing to first element
745       *           equal to or greater than key, or end().
746       *
747       *  This function returns the first element of a subsequence of elements
748       *  that matches the given key.  If unsuccessful it returns an iterator
749       *  pointing to the first element that has a greater value than given key
750       *  or end() if no such element exists.
751       */
752      const_iterator
753      lower_bound(const key_type& __x) const
754      { return _M_t.lower_bound(__x); }
755
756      /**
757       *  @brief Finds the end of a subsequence matching given key.
758       *  @param  x  Key of (key, value) pair to be located.
759       *  @return Iterator pointing to the first element
760       *          greater than key, or end().
761       */
762      iterator
763      upper_bound(const key_type& __x)
764      { return _M_t.upper_bound(__x); }
765
766      /**
767       *  @brief Finds the end of a subsequence matching given key.
768       *  @param  x  Key of (key, value) pair to be located.
769       *  @return  Read-only (constant) iterator pointing to first iterator
770       *           greater than key, or end().
771       */
772      const_iterator
773      upper_bound(const key_type& __x) const
774      { return _M_t.upper_bound(__x); }
775
776      /**
777       *  @brief Finds a subsequence matching given key.
778       *  @param  x  Key of (key, value) pairs to be located.
779       *  @return  Pair of iterators that possibly points to the subsequence
780       *           matching given key.
781       *
782       *  This function is equivalent to
783       *  @code
784       *    std::make_pair(c.lower_bound(val),
785       *                   c.upper_bound(val))
786       *  @endcode
787       *  (but is faster than making the calls separately).
788       *
789       *  This function probably only makes sense for multimaps.
790       */
791      std::pair<iterator, iterator>
792      equal_range(const key_type& __x)
793      { return _M_t.equal_range(__x); }
794
795      /**
796       *  @brief Finds a subsequence matching given key.
797       *  @param  x  Key of (key, value) pairs to be located.
798       *  @return  Pair of read-only (constant) iterators that possibly points
799       *           to the subsequence matching given key.
800       *
801       *  This function is equivalent to
802       *  @code
803       *    std::make_pair(c.lower_bound(val),
804       *                   c.upper_bound(val))
805       *  @endcode
806       *  (but is faster than making the calls separately).
807       *
808       *  This function probably only makes sense for multimaps.
809       */
810      std::pair<const_iterator, const_iterator>
811      equal_range(const key_type& __x) const
812      { return _M_t.equal_range(__x); }
813
814      template<typename _K1, typename _T1, typename _C1, typename _A1>
815        friend bool
816        operator==(const map<_K1, _T1, _C1, _A1>&,
817		   const map<_K1, _T1, _C1, _A1>&);
818
819      template<typename _K1, typename _T1, typename _C1, typename _A1>
820        friend bool
821        operator<(const map<_K1, _T1, _C1, _A1>&,
822		  const map<_K1, _T1, _C1, _A1>&);
823    };
824
825  /**
826   *  @brief  Map equality comparison.
827   *  @param  x  A %map.
828   *  @param  y  A %map of the same type as @a x.
829   *  @return  True iff the size and elements of the maps are equal.
830   *
831   *  This is an equivalence relation.  It is linear in the size of the
832   *  maps.  Maps are considered equivalent if their sizes are equal,
833   *  and if corresponding elements compare equal.
834  */
835  template<typename _Key, typename _Tp, typename _Compare, typename _Alloc>
836    inline bool
837    operator==(const map<_Key, _Tp, _Compare, _Alloc>& __x,
838               const map<_Key, _Tp, _Compare, _Alloc>& __y)
839    { return __x._M_t == __y._M_t; }
840
841  /**
842   *  @brief  Map ordering relation.
843   *  @param  x  A %map.
844   *  @param  y  A %map of the same type as @a x.
845   *  @return  True iff @a x is lexicographically less than @a y.
846   *
847   *  This is a total ordering relation.  It is linear in the size of the
848   *  maps.  The elements must be comparable with @c <.
849   *
850   *  See std::lexicographical_compare() for how the determination is made.
851  */
852  template<typename _Key, typename _Tp, typename _Compare, typename _Alloc>
853    inline bool
854    operator<(const map<_Key, _Tp, _Compare, _Alloc>& __x,
855              const map<_Key, _Tp, _Compare, _Alloc>& __y)
856    { return __x._M_t < __y._M_t; }
857
858  /// Based on operator==
859  template<typename _Key, typename _Tp, typename _Compare, typename _Alloc>
860    inline bool
861    operator!=(const map<_Key, _Tp, _Compare, _Alloc>& __x,
862               const map<_Key, _Tp, _Compare, _Alloc>& __y)
863    { return !(__x == __y); }
864
865  /// Based on operator<
866  template<typename _Key, typename _Tp, typename _Compare, typename _Alloc>
867    inline bool
868    operator>(const map<_Key, _Tp, _Compare, _Alloc>& __x,
869              const map<_Key, _Tp, _Compare, _Alloc>& __y)
870    { return __y < __x; }
871
872  /// Based on operator<
873  template<typename _Key, typename _Tp, typename _Compare, typename _Alloc>
874    inline bool
875    operator<=(const map<_Key, _Tp, _Compare, _Alloc>& __x,
876               const map<_Key, _Tp, _Compare, _Alloc>& __y)
877    { return !(__y < __x); }
878
879  /// Based on operator<
880  template<typename _Key, typename _Tp, typename _Compare, typename _Alloc>
881    inline bool
882    operator>=(const map<_Key, _Tp, _Compare, _Alloc>& __x,
883               const map<_Key, _Tp, _Compare, _Alloc>& __y)
884    { return !(__x < __y); }
885
886  /// See std::map::swap().
887  template<typename _Key, typename _Tp, typename _Compare, typename _Alloc>
888    inline void
889    swap(map<_Key, _Tp, _Compare, _Alloc>& __x,
890	 map<_Key, _Tp, _Compare, _Alloc>& __y)
891    { __x.swap(__y); }
892
893_GLIBCXX_END_NESTED_NAMESPACE
894
895#endif /* _STL_MAP_H */
896