libstdc++
stl_map.h
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00001 // Map implementation -*- C++ -*-
00002 
00003 // Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010,
00004 // 2011 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 bits/stl_map.h
00053  *  This is an internal header file, included by other library headers.
00054  *  Do not attempt to use it directly. @headername{map}
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 #ifdef __GXX_EXPERIMENTAL_CXX0X__
00063 #include <initializer_list>
00064 #endif
00065 
00066 namespace std _GLIBCXX_VISIBILITY(default)
00067 {
00068 _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
00069 
00070   /**
00071    *  @brief A standard container made up of (key,value) pairs, which can be
00072    *  retrieved based on a key, in logarithmic time.
00073    *
00074    *  @ingroup associative_containers
00075    *
00076    *  Meets the requirements of a <a href="tables.html#65">container</a>, a
00077    *  <a href="tables.html#66">reversible container</a>, and an
00078    *  <a href="tables.html#69">associative container</a> (using unique keys).
00079    *  For a @c map<Key,T> the key_type is Key, the mapped_type is T, and the
00080    *  value_type is std::pair<const Key,T>.
00081    *
00082    *  Maps support bidirectional iterators.
00083    *
00084    *  The private tree data is declared exactly the same way for map and
00085    *  multimap; the distinction is made entirely in how the tree functions are
00086    *  called (*_unique versus *_equal, same as the standard).
00087   */
00088   template <typename _Key, typename _Tp, typename _Compare = std::less<_Key>,
00089             typename _Alloc = std::allocator<std::pair<const _Key, _Tp> > >
00090     class map
00091     {
00092     public:
00093       typedef _Key                                          key_type;
00094       typedef _Tp                                           mapped_type;
00095       typedef std::pair<const _Key, _Tp>                    value_type;
00096       typedef _Compare                                      key_compare;
00097       typedef _Alloc                                        allocator_type;
00098 
00099     private:
00100       // concept requirements
00101       typedef typename _Alloc::value_type                   _Alloc_value_type;
00102       __glibcxx_class_requires(_Tp, _SGIAssignableConcept)
00103       __glibcxx_class_requires4(_Compare, bool, _Key, _Key,
00104                 _BinaryFunctionConcept)
00105       __glibcxx_class_requires2(value_type, _Alloc_value_type, _SameTypeConcept)
00106 
00107     public:
00108       class value_compare
00109       : public std::binary_function<value_type, value_type, bool>
00110       {
00111     friend class map<_Key, _Tp, _Compare, _Alloc>;
00112       protected:
00113     _Compare comp;
00114 
00115     value_compare(_Compare __c)
00116     : comp(__c) { }
00117 
00118       public:
00119     bool operator()(const value_type& __x, const value_type& __y) const
00120     { return comp(__x.first, __y.first); }
00121       };
00122 
00123     private:
00124       /// This turns a red-black tree into a [multi]map. 
00125       typedef typename _Alloc::template rebind<value_type>::other 
00126         _Pair_alloc_type;
00127 
00128       typedef _Rb_tree<key_type, value_type, _Select1st<value_type>,
00129                key_compare, _Pair_alloc_type> _Rep_type;
00130 
00131       /// The actual tree structure.
00132       _Rep_type _M_t;
00133 
00134     public:
00135       // many of these are specified differently in ISO, but the following are
00136       // "functionally equivalent"
00137       typedef typename _Pair_alloc_type::pointer         pointer;
00138       typedef typename _Pair_alloc_type::const_pointer   const_pointer;
00139       typedef typename _Pair_alloc_type::reference       reference;
00140       typedef typename _Pair_alloc_type::const_reference const_reference;
00141       typedef typename _Rep_type::iterator               iterator;
00142       typedef typename _Rep_type::const_iterator         const_iterator;
00143       typedef typename _Rep_type::size_type              size_type;
00144       typedef typename _Rep_type::difference_type        difference_type;
00145       typedef typename _Rep_type::reverse_iterator       reverse_iterator;
00146       typedef typename _Rep_type::const_reverse_iterator const_reverse_iterator;
00147 
00148       // [23.3.1.1] construct/copy/destroy
00149       // (get_allocator() is normally listed in this section, but seems to have
00150       // been accidentally omitted in the printed standard)
00151       /**
00152        *  @brief  Default constructor creates no elements.
00153        */
00154       map()
00155       : _M_t() { }
00156 
00157       /**
00158        *  @brief  Creates a %map with no elements.
00159        *  @param  __comp  A comparison object.
00160        *  @param  __a  An allocator object.
00161        */
00162       explicit
00163       map(const _Compare& __comp,
00164       const allocator_type& __a = allocator_type())
00165       : _M_t(__comp, _Pair_alloc_type(__a)) { }
00166 
00167       /**
00168        *  @brief  %Map copy constructor.
00169        *  @param  __x  A %map of identical element and allocator types.
00170        *
00171        *  The newly-created %map uses a copy of the allocation object
00172        *  used by @a __x.
00173        */
00174       map(const map& __x)
00175       : _M_t(__x._M_t) { }
00176 
00177 #ifdef __GXX_EXPERIMENTAL_CXX0X__
00178       /**
00179        *  @brief  %Map move constructor.
00180        *  @param  __x  A %map of identical element and allocator types.
00181        *
00182        *  The newly-created %map contains the exact contents of @a __x.
00183        *  The contents of @a __x are a valid, but unspecified %map.
00184        */
00185       map(map&& __x)
00186       noexcept(is_nothrow_copy_constructible<_Compare>::value)
00187       : _M_t(std::move(__x._M_t)) { }
00188 
00189       /**
00190        *  @brief  Builds a %map from an initializer_list.
00191        *  @param  __l  An initializer_list.
00192        *  @param  __comp  A comparison object.
00193        *  @param  __a  An allocator object.
00194        *
00195        *  Create a %map consisting of copies of the elements in the
00196        *  initializer_list @a __l.
00197        *  This is linear in N if the range is already sorted, and NlogN
00198        *  otherwise (where N is @a __l.size()).
00199        */
00200       map(initializer_list<value_type> __l,
00201       const _Compare& __comp = _Compare(),
00202       const allocator_type& __a = allocator_type())
00203       : _M_t(__comp, _Pair_alloc_type(__a))
00204       { _M_t._M_insert_unique(__l.begin(), __l.end()); }
00205 #endif
00206 
00207       /**
00208        *  @brief  Builds a %map from a range.
00209        *  @param  __first  An input iterator.
00210        *  @param  __last  An input iterator.
00211        *
00212        *  Create a %map consisting of copies of the elements from
00213        *  [__first,__last).  This is linear in N if the range is
00214        *  already sorted, and NlogN otherwise (where N is
00215        *  distance(__first,__last)).
00216        */
00217       template<typename _InputIterator>
00218         map(_InputIterator __first, _InputIterator __last)
00219     : _M_t()
00220         { _M_t._M_insert_unique(__first, __last); }
00221 
00222       /**
00223        *  @brief  Builds a %map from a range.
00224        *  @param  __first  An input iterator.
00225        *  @param  __last  An input iterator.
00226        *  @param  __comp  A comparison functor.
00227        *  @param  __a  An allocator object.
00228        *
00229        *  Create a %map consisting of copies of the elements from
00230        *  [__first,__last).  This is linear in N if the range is
00231        *  already sorted, and NlogN otherwise (where N is
00232        *  distance(__first,__last)).
00233        */
00234       template<typename _InputIterator>
00235         map(_InputIterator __first, _InputIterator __last,
00236         const _Compare& __comp,
00237         const allocator_type& __a = allocator_type())
00238     : _M_t(__comp, _Pair_alloc_type(__a))
00239         { _M_t._M_insert_unique(__first, __last); }
00240 
00241       // FIXME There is no dtor declared, but we should have something
00242       // generated by Doxygen.  I don't know what tags to add to this
00243       // paragraph to make that happen:
00244       /**
00245        *  The dtor only erases the elements, and note that if the elements
00246        *  themselves are pointers, the pointed-to memory is not touched in any
00247        *  way.  Managing the pointer is the user's responsibility.
00248        */
00249 
00250       /**
00251        *  @brief  %Map assignment operator.
00252        *  @param  __x  A %map of identical element and allocator types.
00253        *
00254        *  All the elements of @a __x are copied, but unlike the copy
00255        *  constructor, the allocator object is not copied.
00256        */
00257       map&
00258       operator=(const map& __x)
00259       {
00260     _M_t = __x._M_t;
00261     return *this;
00262       }
00263 
00264 #ifdef __GXX_EXPERIMENTAL_CXX0X__
00265       /**
00266        *  @brief  %Map move assignment operator.
00267        *  @param  __x  A %map of identical element and allocator types.
00268        *
00269        *  The contents of @a __x are moved into this map (without copying).
00270        *  @a __x is a valid, but unspecified %map.
00271        */
00272       map&
00273       operator=(map&& __x)
00274       {
00275     // NB: DR 1204.
00276     // NB: DR 675.
00277     this->clear();
00278     this->swap(__x);
00279     return *this;
00280       }
00281 
00282       /**
00283        *  @brief  %Map list assignment operator.
00284        *  @param  __l  An initializer_list.
00285        *
00286        *  This function fills a %map with copies of the elements in the
00287        *  initializer list @a __l.
00288        *
00289        *  Note that the assignment completely changes the %map and
00290        *  that the resulting %map's size is the same as the number
00291        *  of elements assigned.  Old data may be lost.
00292        */
00293       map&
00294       operator=(initializer_list<value_type> __l)
00295       {
00296     this->clear();
00297     this->insert(__l.begin(), __l.end());
00298     return *this;
00299       }
00300 #endif
00301 
00302       /// Get a copy of the memory allocation object.
00303       allocator_type
00304       get_allocator() const _GLIBCXX_NOEXCEPT
00305       { return allocator_type(_M_t.get_allocator()); }
00306 
00307       // iterators
00308       /**
00309        *  Returns a read/write iterator that points to the first pair in the
00310        *  %map.
00311        *  Iteration is done in ascending order according to the keys.
00312        */
00313       iterator
00314       begin() _GLIBCXX_NOEXCEPT
00315       { return _M_t.begin(); }
00316 
00317       /**
00318        *  Returns a read-only (constant) iterator that points to the first pair
00319        *  in the %map.  Iteration is done in ascending order according to the
00320        *  keys.
00321        */
00322       const_iterator
00323       begin() const _GLIBCXX_NOEXCEPT
00324       { return _M_t.begin(); }
00325 
00326       /**
00327        *  Returns a read/write iterator that points one past the last
00328        *  pair in the %map.  Iteration is done in ascending order
00329        *  according to the keys.
00330        */
00331       iterator
00332       end() _GLIBCXX_NOEXCEPT
00333       { return _M_t.end(); }
00334 
00335       /**
00336        *  Returns a read-only (constant) iterator that points one past the last
00337        *  pair in the %map.  Iteration is done in ascending order according to
00338        *  the keys.
00339        */
00340       const_iterator
00341       end() const _GLIBCXX_NOEXCEPT
00342       { return _M_t.end(); }
00343 
00344       /**
00345        *  Returns a read/write reverse iterator that points to the last pair in
00346        *  the %map.  Iteration is done in descending order according to the
00347        *  keys.
00348        */
00349       reverse_iterator
00350       rbegin() _GLIBCXX_NOEXCEPT
00351       { return _M_t.rbegin(); }
00352 
00353       /**
00354        *  Returns a read-only (constant) reverse iterator that points to the
00355        *  last pair in the %map.  Iteration is done in descending order
00356        *  according to the keys.
00357        */
00358       const_reverse_iterator
00359       rbegin() const _GLIBCXX_NOEXCEPT
00360       { return _M_t.rbegin(); }
00361 
00362       /**
00363        *  Returns a read/write reverse iterator that points to one before the
00364        *  first pair in the %map.  Iteration is done in descending order
00365        *  according to the keys.
00366        */
00367       reverse_iterator
00368       rend() _GLIBCXX_NOEXCEPT
00369       { return _M_t.rend(); }
00370 
00371       /**
00372        *  Returns a read-only (constant) reverse iterator that points to one
00373        *  before the first pair in the %map.  Iteration is done in descending
00374        *  order according to the keys.
00375        */
00376       const_reverse_iterator
00377       rend() const _GLIBCXX_NOEXCEPT
00378       { return _M_t.rend(); }
00379 
00380 #ifdef __GXX_EXPERIMENTAL_CXX0X__
00381       /**
00382        *  Returns a read-only (constant) iterator that points to the first pair
00383        *  in the %map.  Iteration is done in ascending order according to the
00384        *  keys.
00385        */
00386       const_iterator
00387       cbegin() const noexcept
00388       { return _M_t.begin(); }
00389 
00390       /**
00391        *  Returns a read-only (constant) iterator that points one past the last
00392        *  pair in the %map.  Iteration is done in ascending order according to
00393        *  the keys.
00394        */
00395       const_iterator
00396       cend() const noexcept
00397       { return _M_t.end(); }
00398 
00399       /**
00400        *  Returns a read-only (constant) reverse iterator that points to the
00401        *  last pair in the %map.  Iteration is done in descending order
00402        *  according to the keys.
00403        */
00404       const_reverse_iterator
00405       crbegin() const noexcept
00406       { return _M_t.rbegin(); }
00407 
00408       /**
00409        *  Returns a read-only (constant) reverse iterator that points to one
00410        *  before the first pair in the %map.  Iteration is done in descending
00411        *  order according to the keys.
00412        */
00413       const_reverse_iterator
00414       crend() const noexcept
00415       { return _M_t.rend(); }
00416 #endif
00417 
00418       // capacity
00419       /** Returns true if the %map is empty.  (Thus begin() would equal
00420        *  end().)
00421       */
00422       bool
00423       empty() const _GLIBCXX_NOEXCEPT
00424       { return _M_t.empty(); }
00425 
00426       /** Returns the size of the %map.  */
00427       size_type
00428       size() const _GLIBCXX_NOEXCEPT
00429       { return _M_t.size(); }
00430 
00431       /** Returns the maximum size of the %map.  */
00432       size_type
00433       max_size() const _GLIBCXX_NOEXCEPT
00434       { return _M_t.max_size(); }
00435 
00436       // [23.3.1.2] element access
00437       /**
00438        *  @brief  Subscript ( @c [] ) access to %map data.
00439        *  @param  __k  The key for which data should be retrieved.
00440        *  @return  A reference to the data of the (key,data) %pair.
00441        *
00442        *  Allows for easy lookup with the subscript ( @c [] )
00443        *  operator.  Returns data associated with the key specified in
00444        *  subscript.  If the key does not exist, a pair with that key
00445        *  is created using default values, which is then returned.
00446        *
00447        *  Lookup requires logarithmic time.
00448        */
00449       mapped_type&
00450       operator[](const key_type& __k)
00451       {
00452     // concept requirements
00453     __glibcxx_function_requires(_DefaultConstructibleConcept<mapped_type>)
00454 
00455     iterator __i = lower_bound(__k);
00456     // __i->first is greater than or equivalent to __k.
00457     if (__i == end() || key_comp()(__k, (*__i).first))
00458           __i = insert(__i, value_type(__k, mapped_type()));
00459     return (*__i).second;
00460       }
00461 
00462 #ifdef __GXX_EXPERIMENTAL_CXX0X__
00463       mapped_type&
00464       operator[](key_type&& __k)
00465       {
00466     // concept requirements
00467     __glibcxx_function_requires(_DefaultConstructibleConcept<mapped_type>)
00468 
00469     iterator __i = lower_bound(__k);
00470     // __i->first is greater than or equivalent to __k.
00471     if (__i == end() || key_comp()(__k, (*__i).first))
00472           __i = insert(__i, std::make_pair(std::move(__k), mapped_type()));
00473     return (*__i).second;
00474       }
00475 #endif
00476 
00477       // _GLIBCXX_RESOLVE_LIB_DEFECTS
00478       // DR 464. Suggestion for new member functions in standard containers.
00479       /**
00480        *  @brief  Access to %map data.
00481        *  @param  __k  The key for which data should be retrieved.
00482        *  @return  A reference to the data whose key is equivalent to @a __k, if
00483        *           such a data is present in the %map.
00484        *  @throw  std::out_of_range  If no such data is present.
00485        */
00486       mapped_type&
00487       at(const key_type& __k)
00488       {
00489     iterator __i = lower_bound(__k);
00490     if (__i == end() || key_comp()(__k, (*__i).first))
00491       __throw_out_of_range(__N("map::at"));
00492     return (*__i).second;
00493       }
00494 
00495       const mapped_type&
00496       at(const key_type& __k) const
00497       {
00498     const_iterator __i = lower_bound(__k);
00499     if (__i == end() || key_comp()(__k, (*__i).first))
00500       __throw_out_of_range(__N("map::at"));
00501     return (*__i).second;
00502       }
00503 
00504       // modifiers
00505       /**
00506        *  @brief Attempts to insert a std::pair into the %map.
00507 
00508        *  @param __x Pair to be inserted (see std::make_pair for easy
00509        *         creation of pairs).
00510        *
00511        *  @return  A pair, of which the first element is an iterator that 
00512        *           points to the possibly inserted pair, and the second is 
00513        *           a bool that is true if the pair was actually inserted.
00514        *
00515        *  This function attempts to insert a (key, value) %pair into the %map.
00516        *  A %map relies on unique keys and thus a %pair is only inserted if its
00517        *  first element (the key) is not already present in the %map.
00518        *
00519        *  Insertion requires logarithmic time.
00520        */
00521       std::pair<iterator, bool>
00522       insert(const value_type& __x)
00523       { return _M_t._M_insert_unique(__x); }
00524 
00525 #ifdef __GXX_EXPERIMENTAL_CXX0X__
00526       template<typename _Pair, typename = typename
00527            std::enable_if<std::is_convertible<_Pair,
00528                           value_type>::value>::type>
00529         std::pair<iterator, bool>
00530         insert(_Pair&& __x)
00531         { return _M_t._M_insert_unique(std::forward<_Pair>(__x)); }
00532 #endif
00533 
00534 #ifdef __GXX_EXPERIMENTAL_CXX0X__
00535       /**
00536        *  @brief Attempts to insert a list of std::pairs into the %map.
00537        *  @param  __list  A std::initializer_list<value_type> of pairs to be
00538        *                  inserted.
00539        *
00540        *  Complexity similar to that of the range constructor.
00541        */
00542       void
00543       insert(std::initializer_list<value_type> __list)
00544       { insert(__list.begin(), __list.end()); }
00545 #endif
00546 
00547       /**
00548        *  @brief Attempts to insert a std::pair into the %map.
00549        *  @param  __position  An iterator that serves as a hint as to where the
00550        *                    pair should be inserted.
00551        *  @param  __x  Pair to be inserted (see std::make_pair for easy creation
00552        *               of pairs).
00553        *  @return An iterator that points to the element with key of
00554        *           @a __x (may or may not be the %pair passed in).
00555        *
00556 
00557        *  This function is not concerned about whether the insertion
00558        *  took place, and thus does not return a boolean like the
00559        *  single-argument insert() does.  Note that the first
00560        *  parameter is only a hint and can potentially improve the
00561        *  performance of the insertion process.  A bad hint would
00562        *  cause no gains in efficiency.
00563        *
00564        *  See
00565        *  http://gcc.gnu.org/onlinedocs/libstdc++/manual/bk01pt07ch17.html
00566        *  for more on @a hinting.
00567        *
00568        *  Insertion requires logarithmic time (if the hint is not taken).
00569        */
00570       iterator
00571 #ifdef __GXX_EXPERIMENTAL_CXX0X__
00572       insert(const_iterator __position, const value_type& __x)
00573 #else
00574       insert(iterator __position, const value_type& __x)
00575 #endif
00576       { return _M_t._M_insert_unique_(__position, __x); }
00577 
00578 #ifdef __GXX_EXPERIMENTAL_CXX0X__
00579       template<typename _Pair, typename = typename
00580            std::enable_if<std::is_convertible<_Pair,
00581                           value_type>::value>::type>
00582         iterator
00583         insert(const_iterator __position, _Pair&& __x)
00584         { return _M_t._M_insert_unique_(__position,
00585                     std::forward<_Pair>(__x)); }
00586 #endif
00587 
00588       /**
00589        *  @brief Template function that attempts to insert a range of elements.
00590        *  @param  __first  Iterator pointing to the start of the range to be
00591        *                   inserted.
00592        *  @param  __last  Iterator pointing to the end of the range.
00593        *
00594        *  Complexity similar to that of the range constructor.
00595        */
00596       template<typename _InputIterator>
00597         void
00598         insert(_InputIterator __first, _InputIterator __last)
00599         { _M_t._M_insert_unique(__first, __last); }
00600 
00601 #ifdef __GXX_EXPERIMENTAL_CXX0X__
00602       // _GLIBCXX_RESOLVE_LIB_DEFECTS
00603       // DR 130. Associative erase should return an iterator.
00604       /**
00605        *  @brief Erases an element from a %map.
00606        *  @param  __position  An iterator pointing to the element to be erased.
00607        *  @return An iterator pointing to the element immediately following
00608        *          @a position prior to the element being erased. If no such 
00609        *          element exists, end() is returned.
00610        *
00611        *  This function erases an element, pointed to by the given
00612        *  iterator, from a %map.  Note that this function only erases
00613        *  the element, and that if the element is itself a pointer,
00614        *  the pointed-to memory is not touched in any way.  Managing
00615        *  the pointer is the user's responsibility.
00616        */
00617       iterator
00618       erase(const_iterator __position)
00619       { return _M_t.erase(__position); }
00620 
00621       // LWG 2059.
00622       iterator
00623       erase(iterator __position)
00624       { return _M_t.erase(__position); }
00625 #else
00626       /**
00627        *  @brief Erases an element from a %map.
00628        *  @param  __position  An iterator pointing to the element to be erased.
00629        *
00630        *  This function erases an element, pointed to by the given
00631        *  iterator, from a %map.  Note that this function only erases
00632        *  the element, and that if the element is itself a pointer,
00633        *  the pointed-to memory is not touched in any way.  Managing
00634        *  the pointer is the user's responsibility.
00635        */
00636       void
00637       erase(iterator __position)
00638       { _M_t.erase(__position); }
00639 #endif
00640 
00641       /**
00642        *  @brief Erases elements according to the provided key.
00643        *  @param  __x  Key of element to be erased.
00644        *  @return  The number of elements erased.
00645        *
00646        *  This function erases all the elements located by the given key from
00647        *  a %map.
00648        *  Note that this function only erases the element, and that if
00649        *  the element is itself a pointer, the pointed-to memory is not touched
00650        *  in any way.  Managing the pointer is the user's responsibility.
00651        */
00652       size_type
00653       erase(const key_type& __x)
00654       { return _M_t.erase(__x); }
00655 
00656 #ifdef __GXX_EXPERIMENTAL_CXX0X__
00657       // _GLIBCXX_RESOLVE_LIB_DEFECTS
00658       // DR 130. Associative erase should return an iterator.
00659       /**
00660        *  @brief Erases a [first,last) range of elements from a %map.
00661        *  @param  __first  Iterator pointing to the start of the range to be
00662        *                   erased.
00663        *  @param __last Iterator pointing to the end of the range to
00664        *                be erased.
00665        *  @return The iterator @a __last.
00666        *
00667        *  This function erases a sequence of elements from a %map.
00668        *  Note that this function only erases the element, and that if
00669        *  the element is itself a pointer, the pointed-to memory is not touched
00670        *  in any way.  Managing the pointer is the user's responsibility.
00671        */
00672       iterator
00673       erase(const_iterator __first, const_iterator __last)
00674       { return _M_t.erase(__first, __last); }
00675 #else
00676       /**
00677        *  @brief Erases a [__first,__last) range of elements from a %map.
00678        *  @param  __first  Iterator pointing to the start of the range to be
00679        *                   erased.
00680        *  @param __last Iterator pointing to the end of the range to
00681        *                be erased.
00682        *
00683        *  This function erases a sequence of elements from a %map.
00684        *  Note that this function only erases the element, and that if
00685        *  the element is itself a pointer, the pointed-to memory is not touched
00686        *  in any way.  Managing the pointer is the user's responsibility.
00687        */
00688       void
00689       erase(iterator __first, iterator __last)
00690       { _M_t.erase(__first, __last); }
00691 #endif
00692 
00693       /**
00694        *  @brief  Swaps data with another %map.
00695        *  @param  __x  A %map of the same element and allocator types.
00696        *
00697        *  This exchanges the elements between two maps in constant
00698        *  time.  (It is only swapping a pointer, an integer, and an
00699        *  instance of the @c Compare type (which itself is often
00700        *  stateless and empty), so it should be quite fast.)  Note
00701        *  that the global std::swap() function is specialized such
00702        *  that std::swap(m1,m2) will feed to this function.
00703        */
00704       void
00705       swap(map& __x)
00706       { _M_t.swap(__x._M_t); }
00707 
00708       /**
00709        *  Erases all elements in a %map.  Note that this function only
00710        *  erases the elements, and that if the elements themselves are
00711        *  pointers, the pointed-to memory is not touched in any way.
00712        *  Managing the pointer is the user's responsibility.
00713        */
00714       void
00715       clear() _GLIBCXX_NOEXCEPT
00716       { _M_t.clear(); }
00717 
00718       // observers
00719       /**
00720        *  Returns the key comparison object out of which the %map was
00721        *  constructed.
00722        */
00723       key_compare
00724       key_comp() const
00725       { return _M_t.key_comp(); }
00726 
00727       /**
00728        *  Returns a value comparison object, built from the key comparison
00729        *  object out of which the %map was constructed.
00730        */
00731       value_compare
00732       value_comp() const
00733       { return value_compare(_M_t.key_comp()); }
00734 
00735       // [23.3.1.3] map operations
00736       /**
00737        *  @brief Tries to locate an element in a %map.
00738        *  @param  __x  Key of (key, value) %pair to be located.
00739        *  @return  Iterator pointing to sought-after element, or end() if not
00740        *           found.
00741        *
00742        *  This function takes a key and tries to locate the element with which
00743        *  the key matches.  If successful the function returns an iterator
00744        *  pointing to the sought after %pair.  If unsuccessful it returns the
00745        *  past-the-end ( @c end() ) iterator.
00746        */
00747       iterator
00748       find(const key_type& __x)
00749       { return _M_t.find(__x); }
00750 
00751       /**
00752        *  @brief Tries to locate an element in a %map.
00753        *  @param  __x  Key of (key, value) %pair to be located.
00754        *  @return  Read-only (constant) iterator pointing to sought-after
00755        *           element, or end() if not found.
00756        *
00757        *  This function takes a key and tries to locate the element with which
00758        *  the key matches.  If successful the function returns a constant
00759        *  iterator pointing to the sought after %pair. If unsuccessful it
00760        *  returns the past-the-end ( @c end() ) iterator.
00761        */
00762       const_iterator
00763       find(const key_type& __x) const
00764       { return _M_t.find(__x); }
00765 
00766       /**
00767        *  @brief  Finds the number of elements with given key.
00768        *  @param  __x  Key of (key, value) pairs to be located.
00769        *  @return  Number of elements with specified key.
00770        *
00771        *  This function only makes sense for multimaps; for map the result will
00772        *  either be 0 (not present) or 1 (present).
00773        */
00774       size_type
00775       count(const key_type& __x) const
00776       { return _M_t.find(__x) == _M_t.end() ? 0 : 1; }
00777 
00778       /**
00779        *  @brief Finds the beginning of a subsequence matching given key.
00780        *  @param  __x  Key of (key, value) pair to be located.
00781        *  @return  Iterator pointing to first element equal to or greater
00782        *           than key, or end().
00783        *
00784        *  This function returns the first element of a subsequence of elements
00785        *  that matches the given key.  If unsuccessful it returns an iterator
00786        *  pointing to the first element that has a greater value than given key
00787        *  or end() if no such element exists.
00788        */
00789       iterator
00790       lower_bound(const key_type& __x)
00791       { return _M_t.lower_bound(__x); }
00792 
00793       /**
00794        *  @brief Finds the beginning of a subsequence matching given key.
00795        *  @param  __x  Key of (key, value) pair to be located.
00796        *  @return  Read-only (constant) iterator pointing to first element
00797        *           equal to or greater than key, or end().
00798        *
00799        *  This function returns the first element of a subsequence of elements
00800        *  that matches the given key.  If unsuccessful it returns an iterator
00801        *  pointing to the first element that has a greater value than given key
00802        *  or end() if no such element exists.
00803        */
00804       const_iterator
00805       lower_bound(const key_type& __x) const
00806       { return _M_t.lower_bound(__x); }
00807 
00808       /**
00809        *  @brief Finds the end of a subsequence matching given key.
00810        *  @param  __x  Key of (key, value) pair to be located.
00811        *  @return Iterator pointing to the first element
00812        *          greater than key, or end().
00813        */
00814       iterator
00815       upper_bound(const key_type& __x)
00816       { return _M_t.upper_bound(__x); }
00817 
00818       /**
00819        *  @brief Finds the end of a subsequence matching given key.
00820        *  @param  __x  Key of (key, value) pair to be located.
00821        *  @return  Read-only (constant) iterator pointing to first iterator
00822        *           greater than key, or end().
00823        */
00824       const_iterator
00825       upper_bound(const key_type& __x) const
00826       { return _M_t.upper_bound(__x); }
00827 
00828       /**
00829        *  @brief Finds a subsequence matching given key.
00830        *  @param  __x  Key of (key, value) pairs to be located.
00831        *  @return  Pair of iterators that possibly points to the subsequence
00832        *           matching given key.
00833        *
00834        *  This function is equivalent to
00835        *  @code
00836        *    std::make_pair(c.lower_bound(val),
00837        *                   c.upper_bound(val))
00838        *  @endcode
00839        *  (but is faster than making the calls separately).
00840        *
00841        *  This function probably only makes sense for multimaps.
00842        */
00843       std::pair<iterator, iterator>
00844       equal_range(const key_type& __x)
00845       { return _M_t.equal_range(__x); }
00846 
00847       /**
00848        *  @brief Finds a subsequence matching given key.
00849        *  @param  __x  Key of (key, value) pairs to be located.
00850        *  @return  Pair of read-only (constant) iterators that possibly points
00851        *           to the subsequence matching given key.
00852        *
00853        *  This function is equivalent to
00854        *  @code
00855        *    std::make_pair(c.lower_bound(val),
00856        *                   c.upper_bound(val))
00857        *  @endcode
00858        *  (but is faster than making the calls separately).
00859        *
00860        *  This function probably only makes sense for multimaps.
00861        */
00862       std::pair<const_iterator, const_iterator>
00863       equal_range(const key_type& __x) const
00864       { return _M_t.equal_range(__x); }
00865 
00866       template<typename _K1, typename _T1, typename _C1, typename _A1>
00867         friend bool
00868         operator==(const map<_K1, _T1, _C1, _A1>&,
00869            const map<_K1, _T1, _C1, _A1>&);
00870 
00871       template<typename _K1, typename _T1, typename _C1, typename _A1>
00872         friend bool
00873         operator<(const map<_K1, _T1, _C1, _A1>&,
00874           const map<_K1, _T1, _C1, _A1>&);
00875     };
00876 
00877   /**
00878    *  @brief  Map equality comparison.
00879    *  @param  __x  A %map.
00880    *  @param  __y  A %map of the same type as @a x.
00881    *  @return  True iff the size and elements of the maps are equal.
00882    *
00883    *  This is an equivalence relation.  It is linear in the size of the
00884    *  maps.  Maps are considered equivalent if their sizes are equal,
00885    *  and if corresponding elements compare equal.
00886   */
00887   template<typename _Key, typename _Tp, typename _Compare, typename _Alloc>
00888     inline bool
00889     operator==(const map<_Key, _Tp, _Compare, _Alloc>& __x,
00890                const map<_Key, _Tp, _Compare, _Alloc>& __y)
00891     { return __x._M_t == __y._M_t; }
00892 
00893   /**
00894    *  @brief  Map ordering relation.
00895    *  @param  __x  A %map.
00896    *  @param  __y  A %map of the same type as @a x.
00897    *  @return  True iff @a x is lexicographically less than @a y.
00898    *
00899    *  This is a total ordering relation.  It is linear in the size of the
00900    *  maps.  The elements must be comparable with @c <.
00901    *
00902    *  See std::lexicographical_compare() for how the determination is made.
00903   */
00904   template<typename _Key, typename _Tp, typename _Compare, typename _Alloc>
00905     inline bool
00906     operator<(const map<_Key, _Tp, _Compare, _Alloc>& __x,
00907               const map<_Key, _Tp, _Compare, _Alloc>& __y)
00908     { return __x._M_t < __y._M_t; }
00909 
00910   /// Based on operator==
00911   template<typename _Key, typename _Tp, typename _Compare, typename _Alloc>
00912     inline bool
00913     operator!=(const map<_Key, _Tp, _Compare, _Alloc>& __x,
00914                const map<_Key, _Tp, _Compare, _Alloc>& __y)
00915     { return !(__x == __y); }
00916 
00917   /// Based on operator<
00918   template<typename _Key, typename _Tp, typename _Compare, typename _Alloc>
00919     inline bool
00920     operator>(const map<_Key, _Tp, _Compare, _Alloc>& __x,
00921               const map<_Key, _Tp, _Compare, _Alloc>& __y)
00922     { return __y < __x; }
00923 
00924   /// Based on operator<
00925   template<typename _Key, typename _Tp, typename _Compare, typename _Alloc>
00926     inline bool
00927     operator<=(const map<_Key, _Tp, _Compare, _Alloc>& __x,
00928                const map<_Key, _Tp, _Compare, _Alloc>& __y)
00929     { return !(__y < __x); }
00930 
00931   /// Based on operator<
00932   template<typename _Key, typename _Tp, typename _Compare, typename _Alloc>
00933     inline bool
00934     operator>=(const map<_Key, _Tp, _Compare, _Alloc>& __x,
00935                const map<_Key, _Tp, _Compare, _Alloc>& __y)
00936     { return !(__x < __y); }
00937 
00938   /// See std::map::swap().
00939   template<typename _Key, typename _Tp, typename _Compare, typename _Alloc>
00940     inline void
00941     swap(map<_Key, _Tp, _Compare, _Alloc>& __x,
00942      map<_Key, _Tp, _Compare, _Alloc>& __y)
00943     { __x.swap(__y); }
00944 
00945 _GLIBCXX_END_NAMESPACE_CONTAINER
00946 } // namespace std
00947 
00948 #endif /* _STL_MAP_H */