stl_map.h

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00001 // Map implementation -*- C++ -*-
00002 
00003 // Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009
00004 // Free Software Foundation, Inc.
00005 //
00006 // This file is part of the GNU ISO C++ Library.  This library is free
00007 // software; you can redistribute it and/or modify it under the
00008 // terms of the GNU General Public License as published by the
00009 // Free Software Foundation; either version 3, or (at your option)
00010 // any later version.
00011 
00012 // This library is distributed in the hope that it will be useful,
00013 // but WITHOUT ANY WARRANTY; without even the implied warranty of
00014 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
00015 // GNU General Public License for more details.
00016 
00017 // Under Section 7 of GPL version 3, you are granted additional
00018 // permissions described in the GCC Runtime Library Exception, version
00019 // 3.1, as published by the Free Software Foundation.
00020 
00021 // You should have received a copy of the GNU General Public License and
00022 // a copy of the GCC Runtime Library Exception along with this program;
00023 // see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
00024 // <http://www.gnu.org/licenses/>.
00025 
00026 /*
00027  *
00028  * Copyright (c) 1994
00029  * Hewlett-Packard Company
00030  *
00031  * Permission to use, copy, modify, distribute and sell this software
00032  * and its documentation for any purpose is hereby granted without fee,
00033  * provided that the above copyright notice appear in all copies and
00034  * that both that copyright notice and this permission notice appear
00035  * in supporting documentation.  Hewlett-Packard Company makes no
00036  * representations about the suitability of this software for any
00037  * purpose.  It is provided "as is" without express or implied warranty.
00038  *
00039  *
00040  * Copyright (c) 1996,1997
00041  * Silicon Graphics Computer Systems, Inc.
00042  *
00043  * Permission to use, copy, modify, distribute and sell this software
00044  * and its documentation for any purpose is hereby granted without fee,
00045  * provided that the above copyright notice appear in all copies and
00046  * that both that copyright notice and this permission notice appear
00047  * in supporting documentation.  Silicon Graphics makes no
00048  * representations about the suitability of this software for any
00049  * purpose.  It is provided "as is" without express or implied warranty.
00050  */
00051 
00052 /** @file stl_map.h
00053  *  This is an internal header file, included by other library headers.
00054  *  You should not attempt to use it directly.
00055  */
00056 
00057 #ifndef _STL_MAP_H
00058 #define _STL_MAP_H 1
00059 
00060 #include <bits/functexcept.h>
00061 #include <bits/concept_check.h>
00062 #include <initializer_list>
00063 
00064 _GLIBCXX_BEGIN_NESTED_NAMESPACE(std, _GLIBCXX_STD_D)
00065 
00066   /**
00067    *  @brief A standard container made up of (key,value) pairs, which can be
00068    *  retrieved based on a key, in logarithmic time.
00069    *
00070    *  @ingroup associative_containers
00071    *
00072    *  Meets the requirements of a <a href="tables.html#65">container</a>, a
00073    *  <a href="tables.html#66">reversible container</a>, and an
00074    *  <a href="tables.html#69">associative container</a> (using unique keys).
00075    *  For a @c map<Key,T> the key_type is Key, the mapped_type is T, and the
00076    *  value_type is std::pair<const Key,T>.
00077    *
00078    *  Maps support bidirectional iterators.
00079    *
00080    *  The private tree data is declared exactly the same way for map and
00081    *  multimap; the distinction is made entirely in how the tree functions are
00082    *  called (*_unique versus *_equal, same as the standard).
00083   */
00084   template <typename _Key, typename _Tp, typename _Compare = std::less<_Key>,
00085             typename _Alloc = std::allocator<std::pair<const _Key, _Tp> > >
00086     class map
00087     {
00088     public:
00089       typedef _Key                                          key_type;
00090       typedef _Tp                                           mapped_type;
00091       typedef std::pair<const _Key, _Tp>                    value_type;
00092       typedef _Compare                                      key_compare;
00093       typedef _Alloc                                        allocator_type;
00094 
00095     private:
00096       // concept requirements
00097       typedef typename _Alloc::value_type                   _Alloc_value_type;
00098       __glibcxx_class_requires(_Tp, _SGIAssignableConcept)
00099       __glibcxx_class_requires4(_Compare, bool, _Key, _Key,
00100                 _BinaryFunctionConcept)
00101       __glibcxx_class_requires2(value_type, _Alloc_value_type, _SameTypeConcept)
00102 
00103     public:
00104       class value_compare
00105       : public std::binary_function<value_type, value_type, bool>
00106       {
00107     friend class map<_Key, _Tp, _Compare, _Alloc>;
00108       protected:
00109     _Compare comp;
00110 
00111     value_compare(_Compare __c)
00112     : comp(__c) { }
00113 
00114       public:
00115     bool operator()(const value_type& __x, const value_type& __y) const
00116     { return comp(__x.first, __y.first); }
00117       };
00118 
00119     private:
00120       /// This turns a red-black tree into a [multi]map. 
00121       typedef typename _Alloc::template rebind<value_type>::other 
00122         _Pair_alloc_type;
00123 
00124       typedef _Rb_tree<key_type, value_type, _Select1st<value_type>,
00125                key_compare, _Pair_alloc_type> _Rep_type;
00126 
00127       /// The actual tree structure.
00128       _Rep_type _M_t;
00129 
00130     public:
00131       // many of these are specified differently in ISO, but the following are
00132       // "functionally equivalent"
00133       typedef typename _Pair_alloc_type::pointer         pointer;
00134       typedef typename _Pair_alloc_type::const_pointer   const_pointer;
00135       typedef typename _Pair_alloc_type::reference       reference;
00136       typedef typename _Pair_alloc_type::const_reference const_reference;
00137       typedef typename _Rep_type::iterator               iterator;
00138       typedef typename _Rep_type::const_iterator         const_iterator;
00139       typedef typename _Rep_type::size_type              size_type;
00140       typedef typename _Rep_type::difference_type        difference_type;
00141       typedef typename _Rep_type::reverse_iterator       reverse_iterator;
00142       typedef typename _Rep_type::const_reverse_iterator const_reverse_iterator;
00143 
00144       // [23.3.1.1] construct/copy/destroy
00145       // (get_allocator() is normally listed in this section, but seems to have
00146       // been accidentally omitted in the printed standard)
00147       /**
00148        *  @brief  Default constructor creates no elements.
00149        */
00150       map()
00151       : _M_t() { }
00152 
00153       /**
00154        *  @brief  Creates a %map with no elements.
00155        *  @param  comp  A comparison object.
00156        *  @param  a  An allocator object.
00157        */
00158       explicit
00159       map(const _Compare& __comp,
00160       const allocator_type& __a = allocator_type())
00161       : _M_t(__comp, __a) { }
00162 
00163       /**
00164        *  @brief  %Map copy constructor.
00165        *  @param  x  A %map of identical element and allocator types.
00166        *
00167        *  The newly-created %map uses a copy of the allocation object
00168        *  used by @a x.
00169        */
00170       map(const map& __x)
00171       : _M_t(__x._M_t) { }
00172 
00173 #ifdef __GXX_EXPERIMENTAL_CXX0X__
00174       /**
00175        *  @brief  %Map move constructor.
00176        *  @param  x  A %map of identical element and allocator types.
00177        *
00178        *  The newly-created %map contains the exact contents of @a x.
00179        *  The contents of @a x are a valid, but unspecified %map.
00180        */
00181       map(map&& __x)
00182       : _M_t(std::forward<_Rep_type>(__x._M_t)) { }
00183 
00184       /**
00185        *  @brief  Builds a %map from an initializer_list.
00186        *  @param  l  An initializer_list.
00187        *  @param  comp  A comparison object.
00188        *  @param  a  An allocator object.
00189        *
00190        *  Create a %map consisting of copies of the elements in the
00191        *  initializer_list @a l.
00192        *  This is linear in N if the range is already sorted, and NlogN
00193        *  otherwise (where N is @a l.size()).
00194        */
00195       map(initializer_list<value_type> __l,
00196       const _Compare& __c = _Compare(),
00197       const allocator_type& __a = allocator_type())
00198       : _M_t(__c, __a)
00199       { _M_t._M_insert_unique(__l.begin(), __l.end()); }
00200 #endif
00201 
00202       /**
00203        *  @brief  Builds a %map from a range.
00204        *  @param  first  An input iterator.
00205        *  @param  last  An input iterator.
00206        *
00207        *  Create a %map consisting of copies of the elements from [first,last).
00208        *  This is linear in N if the range is already sorted, and NlogN
00209        *  otherwise (where N is distance(first,last)).
00210        */
00211       template<typename _InputIterator>
00212         map(_InputIterator __first, _InputIterator __last)
00213     : _M_t()
00214         { _M_t._M_insert_unique(__first, __last); }
00215 
00216       /**
00217        *  @brief  Builds a %map from a range.
00218        *  @param  first  An input iterator.
00219        *  @param  last  An input iterator.
00220        *  @param  comp  A comparison functor.
00221        *  @param  a  An allocator object.
00222        *
00223        *  Create a %map consisting of copies of the elements from [first,last).
00224        *  This is linear in N if the range is already sorted, and NlogN
00225        *  otherwise (where N is distance(first,last)).
00226        */
00227       template<typename _InputIterator>
00228         map(_InputIterator __first, _InputIterator __last,
00229         const _Compare& __comp,
00230         const allocator_type& __a = allocator_type())
00231     : _M_t(__comp, __a)
00232         { _M_t._M_insert_unique(__first, __last); }
00233 
00234       // FIXME There is no dtor declared, but we should have something
00235       // generated by Doxygen.  I don't know what tags to add to this
00236       // paragraph to make that happen:
00237       /**
00238        *  The dtor only erases the elements, and note that if the elements
00239        *  themselves are pointers, the pointed-to memory is not touched in any
00240        *  way.  Managing the pointer is the user's responsibility.
00241        */
00242 
00243       /**
00244        *  @brief  %Map assignment operator.
00245        *  @param  x  A %map of identical element and allocator types.
00246        *
00247        *  All the elements of @a x are copied, but unlike the copy constructor,
00248        *  the allocator object is not copied.
00249        */
00250       map&
00251       operator=(const map& __x)
00252       {
00253     _M_t = __x._M_t;
00254     return *this;
00255       }
00256 
00257 #ifdef __GXX_EXPERIMENTAL_CXX0X__
00258       /**
00259        *  @brief  %Map move assignment operator.
00260        *  @param  x  A %map of identical element and allocator types.
00261        *
00262        *  The contents of @a x are moved into this map (without copying).
00263        *  @a x is a valid, but unspecified %map.
00264        */
00265       map&
00266       operator=(map&& __x)
00267       {
00268     // NB: DR 675.
00269     this->clear();
00270     this->swap(__x); 
00271     return *this;
00272       }
00273 
00274       /**
00275        *  @brief  %Map list assignment operator.
00276        *  @param  l  An initializer_list.
00277        *
00278        *  This function fills a %map with copies of the elements in the
00279        *  initializer list @a l.
00280        *
00281        *  Note that the assignment completely changes the %map and
00282        *  that the resulting %map's size is the same as the number
00283        *  of elements assigned.  Old data may be lost.
00284        */
00285       map&
00286       operator=(initializer_list<value_type> __l)
00287       {
00288     this->clear();
00289     this->insert(__l.begin(), __l.end());
00290     return *this;
00291       }
00292 #endif
00293 
00294       /// Get a copy of the memory allocation object.
00295       allocator_type
00296       get_allocator() const
00297       { return _M_t.get_allocator(); }
00298 
00299       // iterators
00300       /**
00301        *  Returns a read/write iterator that points to the first pair in the
00302        *  %map.
00303        *  Iteration is done in ascending order according to the keys.
00304        */
00305       iterator
00306       begin()
00307       { return _M_t.begin(); }
00308 
00309       /**
00310        *  Returns a read-only (constant) iterator that points to the first pair
00311        *  in the %map.  Iteration is done in ascending order according to the
00312        *  keys.
00313        */
00314       const_iterator
00315       begin() const
00316       { return _M_t.begin(); }
00317 
00318       /**
00319        *  Returns a read/write iterator that points one past the last
00320        *  pair in the %map.  Iteration is done in ascending order
00321        *  according to the keys.
00322        */
00323       iterator
00324       end()
00325       { return _M_t.end(); }
00326 
00327       /**
00328        *  Returns a read-only (constant) iterator that points one past the last
00329        *  pair in the %map.  Iteration is done in ascending order according to
00330        *  the keys.
00331        */
00332       const_iterator
00333       end() const
00334       { return _M_t.end(); }
00335 
00336       /**
00337        *  Returns a read/write reverse iterator that points to the last pair in
00338        *  the %map.  Iteration is done in descending order according to the
00339        *  keys.
00340        */
00341       reverse_iterator
00342       rbegin()
00343       { return _M_t.rbegin(); }
00344 
00345       /**
00346        *  Returns a read-only (constant) reverse iterator that points to the
00347        *  last pair in the %map.  Iteration is done in descending order
00348        *  according to the keys.
00349        */
00350       const_reverse_iterator
00351       rbegin() const
00352       { return _M_t.rbegin(); }
00353 
00354       /**
00355        *  Returns a read/write reverse iterator that points to one before the
00356        *  first pair in the %map.  Iteration is done in descending order
00357        *  according to the keys.
00358        */
00359       reverse_iterator
00360       rend()
00361       { return _M_t.rend(); }
00362 
00363       /**
00364        *  Returns a read-only (constant) reverse iterator that points to one
00365        *  before the first pair in the %map.  Iteration is done in descending
00366        *  order according to the keys.
00367        */
00368       const_reverse_iterator
00369       rend() const
00370       { return _M_t.rend(); }
00371 
00372 #ifdef __GXX_EXPERIMENTAL_CXX0X__
00373       /**
00374        *  Returns a read-only (constant) iterator that points to the first pair
00375        *  in the %map.  Iteration is done in ascending order according to the
00376        *  keys.
00377        */
00378       const_iterator
00379       cbegin() const
00380       { return _M_t.begin(); }
00381 
00382       /**
00383        *  Returns a read-only (constant) iterator that points one past the last
00384        *  pair in the %map.  Iteration is done in ascending order according to
00385        *  the keys.
00386        */
00387       const_iterator
00388       cend() const
00389       { return _M_t.end(); }
00390 
00391       /**
00392        *  Returns a read-only (constant) reverse iterator that points to the
00393        *  last pair in the %map.  Iteration is done in descending order
00394        *  according to the keys.
00395        */
00396       const_reverse_iterator
00397       crbegin() const
00398       { return _M_t.rbegin(); }
00399 
00400       /**
00401        *  Returns a read-only (constant) reverse iterator that points to one
00402        *  before the first pair in the %map.  Iteration is done in descending
00403        *  order according to the keys.
00404        */
00405       const_reverse_iterator
00406       crend() const
00407       { return _M_t.rend(); }
00408 #endif
00409 
00410       // capacity
00411       /** Returns true if the %map is empty.  (Thus begin() would equal
00412        *  end().)
00413       */
00414       bool
00415       empty() const
00416       { return _M_t.empty(); }
00417 
00418       /** Returns the size of the %map.  */
00419       size_type
00420       size() const
00421       { return _M_t.size(); }
00422 
00423       /** Returns the maximum size of the %map.  */
00424       size_type
00425       max_size() const
00426       { return _M_t.max_size(); }
00427 
00428       // [23.3.1.2] element access
00429       /**
00430        *  @brief  Subscript ( @c [] ) access to %map data.
00431        *  @param  k  The key for which data should be retrieved.
00432        *  @return  A reference to the data of the (key,data) %pair.
00433        *
00434        *  Allows for easy lookup with the subscript ( @c [] )
00435        *  operator.  Returns data associated with the key specified in
00436        *  subscript.  If the key does not exist, a pair with that key
00437        *  is created using default values, which is then returned.
00438        *
00439        *  Lookup requires logarithmic time.
00440        */
00441       mapped_type&
00442       operator[](const key_type& __k)
00443       {
00444     // concept requirements
00445     __glibcxx_function_requires(_DefaultConstructibleConcept<mapped_type>)
00446 
00447     iterator __i = lower_bound(__k);
00448     // __i->first is greater than or equivalent to __k.
00449     if (__i == end() || key_comp()(__k, (*__i).first))
00450           __i = insert(__i, value_type(__k, mapped_type()));
00451     return (*__i).second;
00452       }
00453 
00454       // _GLIBCXX_RESOLVE_LIB_DEFECTS
00455       // DR 464. Suggestion for new member functions in standard containers.
00456       /**
00457        *  @brief  Access to %map data.
00458        *  @param  k  The key for which data should be retrieved.
00459        *  @return  A reference to the data whose key is equivalent to @a k, if
00460        *           such a data is present in the %map.
00461        *  @throw  std::out_of_range  If no such data is present.
00462        */
00463       mapped_type&
00464       at(const key_type& __k)
00465       {
00466     iterator __i = lower_bound(__k);
00467     if (__i == end() || key_comp()(__k, (*__i).first))
00468       __throw_out_of_range(__N("map::at"));
00469     return (*__i).second;
00470       }
00471 
00472       const mapped_type&
00473       at(const key_type& __k) const
00474       {
00475     const_iterator __i = lower_bound(__k);
00476     if (__i == end() || key_comp()(__k, (*__i).first))
00477       __throw_out_of_range(__N("map::at"));
00478     return (*__i).second;
00479       }
00480 
00481       // modifiers
00482       /**
00483        *  @brief Attempts to insert a std::pair into the %map.
00484 
00485        *  @param  x  Pair to be inserted (see std::make_pair for easy creation 
00486        *         of pairs).
00487 
00488        *  @return  A pair, of which the first element is an iterator that 
00489        *           points to the possibly inserted pair, and the second is 
00490        *           a bool that is true if the pair was actually inserted.
00491        *
00492        *  This function attempts to insert a (key, value) %pair into the %map.
00493        *  A %map relies on unique keys and thus a %pair is only inserted if its
00494        *  first element (the key) is not already present in the %map.
00495        *
00496        *  Insertion requires logarithmic time.
00497        */
00498       std::pair<iterator, bool>
00499       insert(const value_type& __x)
00500       { return _M_t._M_insert_unique(__x); }
00501 
00502 #ifdef __GXX_EXPERIMENTAL_CXX0X__
00503       /**
00504        *  @brief Attempts to insert a list of std::pairs into the %map.
00505        *  @param  list  A std::initializer_list<value_type> of pairs to be
00506        *                inserted.
00507        *
00508        *  Complexity similar to that of the range constructor.
00509        */
00510       void
00511       insert(std::initializer_list<value_type> __list)
00512       { insert (__list.begin(), __list.end()); }
00513 #endif
00514 
00515       /**
00516        *  @brief Attempts to insert a std::pair into the %map.
00517        *  @param  position  An iterator that serves as a hint as to where the
00518        *                    pair should be inserted.
00519        *  @param  x  Pair to be inserted (see std::make_pair for easy creation
00520        *             of pairs).
00521        *  @return  An iterator that points to the element with key of @a x (may
00522        *           or may not be the %pair passed in).
00523        *
00524 
00525        *  This function is not concerned about whether the insertion
00526        *  took place, and thus does not return a boolean like the
00527        *  single-argument insert() does.  Note that the first
00528        *  parameter is only a hint and can potentially improve the
00529        *  performance of the insertion process.  A bad hint would
00530        *  cause no gains in efficiency.
00531        *
00532        *  See
00533        *  http://gcc.gnu.org/onlinedocs/libstdc++/manual/bk01pt07ch17.html
00534        *  for more on "hinting".
00535        *
00536        *  Insertion requires logarithmic time (if the hint is not taken).
00537        */
00538       iterator
00539       insert(iterator __position, const value_type& __x)
00540       { return _M_t._M_insert_unique_(__position, __x); }
00541 
00542       /**
00543        *  @brief Template function that attempts to insert a range of elements.
00544        *  @param  first  Iterator pointing to the start of the range to be
00545        *                 inserted.
00546        *  @param  last  Iterator pointing to the end of the range.
00547        *
00548        *  Complexity similar to that of the range constructor.
00549        */
00550       template<typename _InputIterator>
00551         void
00552         insert(_InputIterator __first, _InputIterator __last)
00553         { _M_t._M_insert_unique(__first, __last); }
00554 
00555       /**
00556        *  @brief Erases an element from a %map.
00557        *  @param  position  An iterator pointing to the element to be erased.
00558        *
00559        *  This function erases an element, pointed to by the given
00560        *  iterator, from a %map.  Note that this function only erases
00561        *  the element, and that if the element is itself a pointer,
00562        *  the pointed-to memory is not touched in any way.  Managing
00563        *  the pointer is the user's responsibility.
00564        */
00565       void
00566       erase(iterator __position)
00567       { _M_t.erase(__position); }
00568 
00569       /**
00570        *  @brief Erases elements according to the provided key.
00571        *  @param  x  Key of element to be erased.
00572        *  @return  The number of elements erased.
00573        *
00574        *  This function erases all the elements located by the given key from
00575        *  a %map.
00576        *  Note that this function only erases the element, and that if
00577        *  the element is itself a pointer, the pointed-to memory is not touched
00578        *  in any way.  Managing the pointer is the user's responsibility.
00579        */
00580       size_type
00581       erase(const key_type& __x)
00582       { return _M_t.erase(__x); }
00583 
00584       /**
00585        *  @brief Erases a [first,last) range of elements from a %map.
00586        *  @param  first  Iterator pointing to the start of the range to be
00587        *                 erased.
00588        *  @param  last  Iterator pointing to the end of the range to be erased.
00589        *
00590        *  This function erases a sequence of elements from a %map.
00591        *  Note that this function only erases the element, and that if
00592        *  the element is itself a pointer, the pointed-to memory is not touched
00593        *  in any way.  Managing the pointer is the user's responsibility.
00594        */
00595       void
00596       erase(iterator __first, iterator __last)
00597       { _M_t.erase(__first, __last); }
00598 
00599       /**
00600        *  @brief  Swaps data with another %map.
00601        *  @param  x  A %map of the same element and allocator types.
00602        *
00603        *  This exchanges the elements between two maps in constant
00604        *  time.  (It is only swapping a pointer, an integer, and an
00605        *  instance of the @c Compare type (which itself is often
00606        *  stateless and empty), so it should be quite fast.)  Note
00607        *  that the global std::swap() function is specialized such
00608        *  that std::swap(m1,m2) will feed to this function.
00609        */
00610       void
00611 #ifdef __GXX_EXPERIMENTAL_CXX0X__
00612       swap(map&& __x)
00613 #else
00614       swap(map& __x)
00615 #endif
00616       { _M_t.swap(__x._M_t); }
00617 
00618       /**
00619        *  Erases all elements in a %map.  Note that this function only
00620        *  erases the elements, and that if the elements themselves are
00621        *  pointers, the pointed-to memory is not touched in any way.
00622        *  Managing the pointer is the user's responsibility.
00623        */
00624       void
00625       clear()
00626       { _M_t.clear(); }
00627 
00628       // observers
00629       /**
00630        *  Returns the key comparison object out of which the %map was
00631        *  constructed.
00632        */
00633       key_compare
00634       key_comp() const
00635       { return _M_t.key_comp(); }
00636 
00637       /**
00638        *  Returns a value comparison object, built from the key comparison
00639        *  object out of which the %map was constructed.
00640        */
00641       value_compare
00642       value_comp() const
00643       { return value_compare(_M_t.key_comp()); }
00644 
00645       // [23.3.1.3] map operations
00646       /**
00647        *  @brief Tries to locate an element in a %map.
00648        *  @param  x  Key of (key, value) %pair to be located.
00649        *  @return  Iterator pointing to sought-after element, or end() if not
00650        *           found.
00651        *
00652        *  This function takes a key and tries to locate the element with which
00653        *  the key matches.  If successful the function returns an iterator
00654        *  pointing to the sought after %pair.  If unsuccessful it returns the
00655        *  past-the-end ( @c end() ) iterator.
00656        */
00657       iterator
00658       find(const key_type& __x)
00659       { return _M_t.find(__x); }
00660 
00661       /**
00662        *  @brief Tries to locate an element in a %map.
00663        *  @param  x  Key of (key, value) %pair to be located.
00664        *  @return  Read-only (constant) iterator pointing to sought-after
00665        *           element, or end() if not found.
00666        *
00667        *  This function takes a key and tries to locate the element with which
00668        *  the key matches.  If successful the function returns a constant
00669        *  iterator pointing to the sought after %pair. If unsuccessful it
00670        *  returns the past-the-end ( @c end() ) iterator.
00671        */
00672       const_iterator
00673       find(const key_type& __x) const
00674       { return _M_t.find(__x); }
00675 
00676       /**
00677        *  @brief  Finds the number of elements with given key.
00678        *  @param  x  Key of (key, value) pairs to be located.
00679        *  @return  Number of elements with specified key.
00680        *
00681        *  This function only makes sense for multimaps; for map the result will
00682        *  either be 0 (not present) or 1 (present).
00683        */
00684       size_type
00685       count(const key_type& __x) const
00686       { return _M_t.find(__x) == _M_t.end() ? 0 : 1; }
00687 
00688       /**
00689        *  @brief Finds the beginning of a subsequence matching given key.
00690        *  @param  x  Key of (key, value) pair to be located.
00691        *  @return  Iterator pointing to first element equal to or greater
00692        *           than key, or end().
00693        *
00694        *  This function returns the first element of a subsequence of elements
00695        *  that matches the given key.  If unsuccessful it returns an iterator
00696        *  pointing to the first element that has a greater value than given key
00697        *  or end() if no such element exists.
00698        */
00699       iterator
00700       lower_bound(const key_type& __x)
00701       { return _M_t.lower_bound(__x); }
00702 
00703       /**
00704        *  @brief Finds the beginning of a subsequence matching given key.
00705        *  @param  x  Key of (key, value) pair to be located.
00706        *  @return  Read-only (constant) iterator pointing to first element
00707        *           equal to or greater than key, or end().
00708        *
00709        *  This function returns the first element of a subsequence of elements
00710        *  that matches the given key.  If unsuccessful it returns an iterator
00711        *  pointing to the first element that has a greater value than given key
00712        *  or end() if no such element exists.
00713        */
00714       const_iterator
00715       lower_bound(const key_type& __x) const
00716       { return _M_t.lower_bound(__x); }
00717 
00718       /**
00719        *  @brief Finds the end of a subsequence matching given key.
00720        *  @param  x  Key of (key, value) pair to be located.
00721        *  @return Iterator pointing to the first element
00722        *          greater than key, or end().
00723        */
00724       iterator
00725       upper_bound(const key_type& __x)
00726       { return _M_t.upper_bound(__x); }
00727 
00728       /**
00729        *  @brief Finds the end of a subsequence matching given key.
00730        *  @param  x  Key of (key, value) pair to be located.
00731        *  @return  Read-only (constant) iterator pointing to first iterator
00732        *           greater than key, or end().
00733        */
00734       const_iterator
00735       upper_bound(const key_type& __x) const
00736       { return _M_t.upper_bound(__x); }
00737 
00738       /**
00739        *  @brief Finds a subsequence matching given key.
00740        *  @param  x  Key of (key, value) pairs to be located.
00741        *  @return  Pair of iterators that possibly points to the subsequence
00742        *           matching given key.
00743        *
00744        *  This function is equivalent to
00745        *  @code
00746        *    std::make_pair(c.lower_bound(val),
00747        *                   c.upper_bound(val))
00748        *  @endcode
00749        *  (but is faster than making the calls separately).
00750        *
00751        *  This function probably only makes sense for multimaps.
00752        */
00753       std::pair<iterator, iterator>
00754       equal_range(const key_type& __x)
00755       { return _M_t.equal_range(__x); }
00756 
00757       /**
00758        *  @brief Finds a subsequence matching given key.
00759        *  @param  x  Key of (key, value) pairs to be located.
00760        *  @return  Pair of read-only (constant) iterators that possibly points
00761        *           to the subsequence matching given key.
00762        *
00763        *  This function is equivalent to
00764        *  @code
00765        *    std::make_pair(c.lower_bound(val),
00766        *                   c.upper_bound(val))
00767        *  @endcode
00768        *  (but is faster than making the calls separately).
00769        *
00770        *  This function probably only makes sense for multimaps.
00771        */
00772       std::pair<const_iterator, const_iterator>
00773       equal_range(const key_type& __x) const
00774       { return _M_t.equal_range(__x); }
00775 
00776       template<typename _K1, typename _T1, typename _C1, typename _A1>
00777         friend bool
00778         operator==(const map<_K1, _T1, _C1, _A1>&,
00779            const map<_K1, _T1, _C1, _A1>&);
00780 
00781       template<typename _K1, typename _T1, typename _C1, typename _A1>
00782         friend bool
00783         operator<(const map<_K1, _T1, _C1, _A1>&,
00784           const map<_K1, _T1, _C1, _A1>&);
00785     };
00786 
00787   /**
00788    *  @brief  Map equality comparison.
00789    *  @param  x  A %map.
00790    *  @param  y  A %map of the same type as @a x.
00791    *  @return  True iff the size and elements of the maps are equal.
00792    *
00793    *  This is an equivalence relation.  It is linear in the size of the
00794    *  maps.  Maps are considered equivalent if their sizes are equal,
00795    *  and if corresponding elements compare equal.
00796   */
00797   template<typename _Key, typename _Tp, typename _Compare, typename _Alloc>
00798     inline bool
00799     operator==(const map<_Key, _Tp, _Compare, _Alloc>& __x,
00800                const map<_Key, _Tp, _Compare, _Alloc>& __y)
00801     { return __x._M_t == __y._M_t; }
00802 
00803   /**
00804    *  @brief  Map ordering relation.
00805    *  @param  x  A %map.
00806    *  @param  y  A %map of the same type as @a x.
00807    *  @return  True iff @a x is lexicographically less than @a y.
00808    *
00809    *  This is a total ordering relation.  It is linear in the size of the
00810    *  maps.  The elements must be comparable with @c <.
00811    *
00812    *  See std::lexicographical_compare() for how the determination is made.
00813   */
00814   template<typename _Key, typename _Tp, typename _Compare, typename _Alloc>
00815     inline bool
00816     operator<(const map<_Key, _Tp, _Compare, _Alloc>& __x,
00817               const map<_Key, _Tp, _Compare, _Alloc>& __y)
00818     { return __x._M_t < __y._M_t; }
00819 
00820   /// Based on operator==
00821   template<typename _Key, typename _Tp, typename _Compare, typename _Alloc>
00822     inline bool
00823     operator!=(const map<_Key, _Tp, _Compare, _Alloc>& __x,
00824                const map<_Key, _Tp, _Compare, _Alloc>& __y)
00825     { return !(__x == __y); }
00826 
00827   /// Based on operator<
00828   template<typename _Key, typename _Tp, typename _Compare, typename _Alloc>
00829     inline bool
00830     operator>(const map<_Key, _Tp, _Compare, _Alloc>& __x,
00831               const map<_Key, _Tp, _Compare, _Alloc>& __y)
00832     { return __y < __x; }
00833 
00834   /// Based on operator<
00835   template<typename _Key, typename _Tp, typename _Compare, typename _Alloc>
00836     inline bool
00837     operator<=(const map<_Key, _Tp, _Compare, _Alloc>& __x,
00838                const map<_Key, _Tp, _Compare, _Alloc>& __y)
00839     { return !(__y < __x); }
00840 
00841   /// Based on operator<
00842   template<typename _Key, typename _Tp, typename _Compare, typename _Alloc>
00843     inline bool
00844     operator>=(const map<_Key, _Tp, _Compare, _Alloc>& __x,
00845                const map<_Key, _Tp, _Compare, _Alloc>& __y)
00846     { return !(__x < __y); }
00847 
00848   /// See std::map::swap().
00849   template<typename _Key, typename _Tp, typename _Compare, typename _Alloc>
00850     inline void
00851     swap(map<_Key, _Tp, _Compare, _Alloc>& __x,
00852      map<_Key, _Tp, _Compare, _Alloc>& __y)
00853     { __x.swap(__y); }
00854 
00855 #ifdef __GXX_EXPERIMENTAL_CXX0X__
00856   template<typename _Key, typename _Tp, typename _Compare, typename _Alloc>
00857     inline void
00858     swap(map<_Key, _Tp, _Compare, _Alloc>&& __x,
00859      map<_Key, _Tp, _Compare, _Alloc>& __y)
00860     { __x.swap(__y); }
00861 
00862   template<typename _Key, typename _Tp, typename _Compare, typename _Alloc>
00863     inline void
00864     swap(map<_Key, _Tp, _Compare, _Alloc>& __x,
00865      map<_Key, _Tp, _Compare, _Alloc>&& __y)
00866     { __x.swap(__y); }
00867 #endif
00868 
00869 _GLIBCXX_END_NESTED_NAMESPACE
00870 
00871 #endif /* _STL_MAP_H */

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