src/lemon/bits/map_iterator.h
author athos
Mon, 11 Apr 2005 15:46:14 +0000
changeset 1339 26a88d12d1a6
parent 1271 40e5d0d44a65
child 1359 1581f961cfaa
permissions -rw-r--r--
A little has been done. Some important questions arised.
     1 /* -*- C++ -*-
     2  * src/lemon/map_iterator.h - Part of LEMON, a generic C++ optimization library
     3  *
     4  * Copyright (C) 2005 Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport
     5  * (Egervary Combinatorial Optimization Research Group, EGRES).
     6  *
     7  * Permission to use, modify and distribute this software is granted
     8  * provided that this copyright notice appears in all copies. For
     9  * precise terms see the accompanying LICENSE file.
    10  *
    11  * This software is provided "AS IS" with no warranty of any kind,
    12  * express or implied, and with no claim as to its suitability for any
    13  * purpose.
    14  *
    15  */
    16 
    17 #ifndef LEMON_MAP_ITERATOR_H
    18 #define LEMON_MAP_ITERATOR_H
    19 
    20 #include <iterator>
    21 
    22 #include <lemon/bits/extended_pair.h>
    23 #include <lemon/map_utils.h>
    24 
    25 ///\ingroup graphmaps
    26 ///\file
    27 ///\brief Iterators on the maps.
    28 
    29 namespace lemon {
    30 
    31   /// \addtogroup graphmaps
    32   /// @{
    33 
    34   /** The base class all of the map iterators.
    35    *  The class defines the typedefs of the iterators,
    36    *  simple step functions and equality operators.
    37    */ 
    38 
    39   template <
    40     typename _Graph,
    41     typename _Item>
    42   class MapIteratorBase {
    43 
    44   protected:
    45 
    46     /// The key type of the iterator.
    47     typedef typename ItemSetTraits<_Graph, _Item>::ItemIt ItemIt;
    48 
    49     ItemIt it;
    50 
    51     /// Default constructor.
    52     MapIteratorBase() {}
    53 
    54     /// ItemIt initialized MapIteratorBase constructor.
    55     MapIteratorBase(const ItemIt _it) : it(_it) {}
    56 
    57   public:
    58 
    59     /// Stepping forward in the map.   
    60     void increment() { 
    61       ++it; 
    62     }
    63 
    64     /// The equality operator of the map.
    65     bool operator==(const MapIteratorBase& _it) const {
    66       return _it.it == it;
    67     }
    68 	
    69     /// The not-equality operator of the map.
    70     bool operator!=(const MapIteratorBase& _it) const {
    71       return !(*this == _it);
    72     }
    73   };
    74 
    75 
    76   template <
    77     typename _Graph,
    78     typename _Item,
    79     typename _Map>
    80   class MapConstIterator;
    81 
    82   /** Compatible iterator with the stl maps' iterators.
    83    * It iterates on pairs of a key and a value.
    84    */
    85   template <
    86     typename _Graph,
    87     typename _Item,
    88     typename _Map>
    89   class MapIterator : public MapIteratorBase<_Graph, _Item> {
    90 
    91     friend class MapConstIterator<_Graph, _Item, _Map>;
    92 
    93 
    94   public:
    95 
    96     /// The iterator base class.
    97     typedef MapIteratorBase<_Graph, _Item> Parent;
    98 
    99     typedef _Item Item;
   100     typedef _Map Map;
   101     typedef _Graph Graph;
   102 
   103   protected:
   104 
   105     typedef typename Parent::ItemIt ItemIt;
   106 
   107     typedef typename ReferenceMapTraits<_Map>::Value MapValue;
   108     typedef typename ReferenceMapTraits<_Map>::Reference MapReference;
   109     
   110   public:
   111 
   112     /// The value type of the iterator.
   113     typedef extended_pair<Item, const Item&,
   114       MapValue, const MapValue&> Value;
   115 
   116     /// The reference type of the iterator. 
   117     typedef extended_pair<const Item&, const Item&, 
   118       MapReference, MapReference> Reference;
   119 
   120     /// Default constructor. 
   121     MapIterator() {}
   122 
   123     /// Constructor to initalize the iterators returned 
   124     /// by the begin() and end().
   125     MapIterator(Map& _map, const ItemIt& _it) 
   126       : Parent(_it), map(&_map) {}
   127 
   128     /// Dereference operator for the iterator.
   129     Reference operator*() {
   130       return Reference(Parent::it, (*map)[Parent::it]);
   131     }
   132 
   133     /// The pointer type of the iterator.
   134     class Pointer {
   135       friend class MapIterator;
   136     protected:
   137       Reference data;
   138       Pointer(const Item& item, MapReference val) 
   139 	: data(item, val) {}
   140     public:
   141       Reference* operator->() {return &data;}
   142     };
   143 
   144     /// Arrow operator for the iterator.
   145     Pointer operator->() {
   146       return Pointer(Parent::it, (*map)[Parent::it]); 
   147     }
   148 	
   149     /// The pre increment operator of the iterator.
   150     MapIterator& operator++() { 
   151       Parent::increment(); 
   152       return *this; 
   153     }
   154 
   155     /// The post increment operator of the iterator.
   156     MapIterator operator++(int) { 
   157       MapIterator tmp(*this); 
   158       Parent::increment(); 
   159       return tmp; 
   160     }
   161 
   162   protected:
   163 
   164     Map* map;
   165 
   166   public:
   167     // STL  compatibility typedefs.
   168     typedef std::forward_iterator_tag iterator_category;
   169     typedef int difference_type;
   170     typedef Value value_type;
   171     typedef Reference reference;
   172     typedef Pointer pointer;
   173   };
   174 
   175   /** Compatible iterator with the stl maps' iterators.
   176    *  It iterates on pairs of a key and a value.
   177    */
   178   template <
   179     typename _Graph,
   180     typename _Item,
   181     typename _Map>
   182   class MapConstIterator : public MapIteratorBase<_Graph, _Item> {
   183 
   184   public:
   185 
   186     /// The iterator base class.
   187     typedef MapIteratorBase<_Graph, _Item> Parent;
   188 
   189     typedef _Graph Graph;
   190     typedef _Item Item;
   191     typedef _Map Map;
   192 
   193   protected:
   194 
   195     typedef typename Parent::ItemIt ItemIt;
   196 
   197     typedef typename ReferenceMapTraits<_Map>::Value MapValue;
   198     typedef typename ReferenceMapTraits<_Map>::ConstReference
   199     MapReference;
   200     
   201   public:
   202 
   203     /// The value type of the iterator.
   204     typedef extended_pair<Item, const Item&,
   205       MapValue, const MapValue&> Value;
   206 
   207     /// The reference type of the iterator. 
   208     typedef extended_pair<const Item&, const Item&, 
   209       MapReference, MapReference> Reference;
   210 
   211     /// Default constructor. 
   212     MapConstIterator() {}
   213 
   214     /// Constructor to initalize the iterators returned 
   215     /// by the begin() and end().
   216     MapConstIterator(const Map& _map, const ItemIt& _it) 
   217       : Parent(_it), map(&_map) {}
   218 
   219     /// Dereference operator for the iterator.
   220     Reference operator*() {
   221       return Reference(Parent::it, (*map)[Parent::it]);
   222     }
   223 
   224     /// The pointer type of the iterator.
   225     class Pointer {
   226       friend class MapConstIterator;
   227     protected:
   228       Reference data;
   229       Pointer(const Item& item, MapReference val) 
   230 	: data(item, val) {}
   231     public:
   232       Reference* operator->() {return &data;}
   233     };
   234 
   235     /// Arrow operator for the iterator.
   236     Pointer operator->() {
   237       return Pointer(Parent::it, ((*map)[Parent::it])); 
   238     }
   239 	
   240     /// The pre increment operator of the iterator.
   241     MapConstIterator& operator++() { 
   242       Parent::increment(); 
   243       return *this; 
   244     }
   245 
   246     /// The post increment operator of the iterator.
   247     MapConstIterator operator++(int) { 
   248       MapConstIterator tmp(*this); 
   249       Parent::increment(); 
   250       return tmp; 
   251     }
   252 
   253   protected:
   254     const Map* map;
   255 
   256   public:
   257     // STL  compatibility typedefs.
   258     typedef std::forward_iterator_tag iterator_category;
   259     typedef int difference_type;
   260     typedef Value value_type;
   261     typedef Reference reference;
   262     typedef Pointer pointer;
   263   };
   264  
   265   /** The class makes the ItemIt to an stl compatible iterator
   266    *  with dereferencing operator.
   267    */
   268   template <
   269     typename _Graph,
   270     typename _Item>
   271   class MapConstKeyIterator : public MapIteratorBase<_Graph, _Item> {
   272 
   273   public:
   274 
   275     /// The iterator base class.
   276     typedef MapIteratorBase<_Graph, _Item> Parent;
   277  
   278     typedef _Graph Graph;
   279     typedef _Item Item;
   280 
   281   protected:
   282     /// The iterator to iterate on the keys.
   283     typedef typename Parent::ItemIt ItemIt;
   284 
   285   public:
   286 
   287     typedef Item Value;
   288     typedef const Item& Reference;
   289     typedef const Item* Pointer;
   290 
   291     /// Default constructor.
   292     MapConstKeyIterator() {}
   293 
   294     /// ItemIt initialized iterator.
   295     MapConstKeyIterator(const ItemIt& pit) : Parent(pit) {}
   296 
   297     /// The pre increment operator of the iterator.
   298     MapConstKeyIterator& operator++() {
   299       Parent::increment(); 
   300       return *this; 
   301     }
   302 
   303     /// The post increment operator of the iterator.
   304     MapConstKeyIterator operator++(int) {
   305       MapConstKeyIterator tmp(*this);
   306       Parent::increment();
   307       return tmp;
   308     }
   309 
   310     /// The dereferencing operator of the iterator.
   311     Item operator*() const {
   312       return static_cast<Item>(Parent::it);
   313     }
   314 
   315   public:
   316     // STL  compatibility typedefs.
   317     typedef std::input_iterator_tag iterator_category;
   318     typedef int difference_type;
   319     typedef Value value_type;
   320     typedef Reference reference;
   321     typedef Pointer pointer;
   322   };
   323 
   324   template <
   325     typename _Graph, 
   326     typename _Item,
   327     typename _Map>
   328   class MapConstValueIterator;
   329 
   330   /** MapValueIterator creates an stl compatible iterator
   331    *  for the values.
   332    */
   333   template <
   334     typename _Graph,
   335     typename _Item,
   336     typename _Map>
   337   class MapValueIterator : public MapIteratorBase<_Graph, _Item> {
   338 
   339     friend class MapConstValueIterator<_Graph, _Item, _Map>;
   340 
   341   public:
   342 
   343     /// The iterator base class.
   344     typedef MapIteratorBase<_Graph, _Item> Parent;
   345 
   346     typedef _Graph Graph;
   347     typedef _Item Item;
   348     typedef _Map Map;
   349 
   350   protected:
   351 
   352     /// The iterator to iterate on the keys.
   353     typedef typename Parent::ItemIt ItemIt;
   354 
   355     /// The value type of the iterator.
   356     typedef typename ReferenceMapTraits<Map>::Value MapValue;
   357     /// The reference type of the iterator.
   358     typedef typename ReferenceMapTraits<Map>::Reference MapReference;
   359     /// The pointer type of the iterator.
   360     typedef typename ReferenceMapTraits<Map>::Pointer MapPointer;
   361 
   362   public:
   363 
   364     typedef MapValue Value;
   365     typedef MapReference Reference;
   366     typedef MapPointer Pointer;
   367 
   368     /// Default constructor.
   369     MapValueIterator() {}
   370 
   371     /// Map and ItemIt initialized iterator.
   372     MapValueIterator(Map& _map, const ItemIt& _it) 
   373       : Parent(_it), map(&_map) {}
   374     
   375 
   376     /// The pre increment operator of the iterator.
   377     MapValueIterator& operator++() {
   378       Parent::increment(); 
   379       return *this; 
   380     }
   381 
   382     /// The post increment operator of the iterator.
   383     MapValueIterator operator++(int) {
   384       MapValueIterator tmp(*this);
   385       Parent::increment();
   386       return tmp;
   387     }
   388 
   389     /// The dereferencing operator of the iterator.
   390     Reference operator*() const {
   391       return (*map)[Parent::it];
   392     }
   393 
   394     /// The arrow operator of the iterator.
   395     Pointer operator->() const {
   396       return &(operator*());
   397     }
   398 
   399   protected:
   400 
   401     Map* map;
   402 
   403   public:
   404     // STL  compatibility typedefs.
   405     typedef std::forward_iterator_tag iterator_category;
   406     typedef int difference_type;
   407     typedef Value value_type;
   408     typedef Reference reference;
   409     typedef Pointer pointer;
   410   };
   411 
   412   /** MapValueIterator creates an stl compatible iterator
   413    *  for the values.
   414    */
   415   template <
   416     typename _Graph,
   417     typename _Item,
   418     typename _Map>
   419   class MapConstValueIterator : public MapIteratorBase<_Graph, _Item> {
   420 
   421   public:
   422 
   423     /// The iterator base class.
   424     typedef MapIteratorBase<_Graph, _Item> Parent;
   425 
   426     typedef _Graph Graph;
   427     typedef _Item Item;
   428     typedef _Map Map;
   429 
   430   protected:
   431 
   432     /// The iterator to iterate on the keys.
   433     typedef typename Parent::ItemIt ItemIt;
   434 
   435     /// The value type of the iterator.
   436     typedef typename ReferenceMapTraits<Map>::Value MapValue;
   437     /// The reference type of the iterator.
   438     typedef typename ReferenceMapTraits<Map>::ConstReference MapReference;
   439     /// The pointer type of the iterator.
   440     typedef typename ReferenceMapTraits<Map>::ConstPointer MapPointer;
   441 
   442   public:
   443 
   444     typedef MapValue Value;
   445     typedef MapReference Reference;
   446     typedef MapPointer Pointer;
   447 
   448     /// Default constructor.
   449     MapConstValueIterator() {}
   450 
   451     /// Map and ItemIt initialized iterator.
   452     MapConstValueIterator(const Map& _map, const ItemIt& _it) 
   453       : Parent(_it), map(&_map) {}
   454     
   455 
   456     /// The pre increment operator of the iterator.
   457     MapConstValueIterator& operator++() {
   458       Parent::increment(); 
   459       return *this; 
   460     }
   461 
   462     /// The post increment operator of the iterator.
   463     MapConstValueIterator operator++(int) {
   464       MapConstValueIterator tmp(*this);
   465       Parent::increment();
   466       return tmp;
   467     }
   468 
   469     /// The dereferencing operator of the iterator.
   470     Reference operator*() const {
   471       return (*map)[Parent::it];
   472     }
   473 
   474     /// The arrow operator of the iterator.
   475     Pointer operator->() const {
   476       return &(operator*());
   477     }
   478 
   479   protected:
   480 
   481     const Map* map;
   482 
   483   public:
   484     // STL  compatibility typedefs.
   485     typedef std::forward_iterator_tag iterator_category;
   486     typedef int difference_type;
   487     typedef Value value_type;
   488     typedef Reference reference;
   489     typedef Pointer pointer;
   490   };
   491 
   492 
   493   /** This class makes from a map an iteratable set
   494    *  which contains all the keys of the map.
   495    */
   496   template <typename _Graph, typename _Item>
   497   class MapConstKeySet {
   498 
   499   public:
   500 
   501     typedef _Graph Graph;
   502     /// The key type of the iterator.
   503     typedef _Item Item;
   504     /// The iterator to iterate on the keys.
   505 
   506   protected:
   507 
   508     typedef typename ItemSetTraits<_Graph, _Item>::ItemIt ItemIt;
   509 
   510   public:
   511 
   512     /// The map initialized const key set.
   513     MapConstKeySet(const Graph& _graph) : graph(&_graph) {}
   514 
   515     /// The const iterator of the set.
   516     typedef MapConstKeyIterator<_Graph, _Item> ConstIterator;
   517 
   518     typedef typename ConstIterator::Value Value;
   519     /// The reference type of the iterator.
   520     typedef typename ConstIterator::Reference ConstReference;
   521     /// The pointer type of the iterator.
   522     typedef typename ConstIterator::Pointer ConstPointer;
   523 
   524     /// It gives back the const iterator pointed to the first element.
   525     ConstIterator begin() const {
   526       return ConstIterator(ItemIt(*graph));
   527     }
   528             
   529     /// It gives back the const iterator pointed to the first ivalid element.
   530     ConstIterator end() const {
   531       return ConstIterator(ItemIt(INVALID));
   532     }
   533 
   534   protected:
   535 
   536     const Graph* graph;
   537  
   538   public:
   539     // STL  compatibility typedefs.
   540     typedef Value value_type;
   541     typedef ConstIterator const_iterator;
   542     typedef ConstReference const_reference;
   543     typedef ConstPointer const_pointer;
   544     typedef int difference_type;
   545   };
   546 
   547   /** This class makes from a map an iteratable set
   548    *  which contains all the values of the map.
   549    *  The values cannot be modified.
   550    */
   551   template <typename _Graph, typename _Item, typename _Map>
   552   class MapConstValueSet {
   553 
   554   public:
   555     
   556     typedef _Graph Graph;
   557     typedef _Item Item;
   558     typedef _Map Map;
   559 
   560   protected:
   561 
   562     /// The iterator to iterate on the keys.
   563     typedef typename ItemSetTraits<Graph, Item>::ItemIt ItemIt;
   564 
   565   public:
   566 
   567     /// The map initialized const value set.
   568     MapConstValueSet(const Graph& _graph, const Map& _map) 
   569       : graph(&_graph), map(&_map) {}
   570 
   571     /// The const iterator of the set.
   572     typedef MapConstValueIterator<_Graph, _Item, _Map> ConstIterator;
   573 
   574     typedef typename ConstIterator::Value Value;
   575     typedef typename ConstIterator::Reference ConstReference;
   576     typedef typename ConstIterator::Pointer ConstPointer;
   577 
   578     /// It gives back the const iterator pointed to the first element.
   579     ConstIterator begin() const {
   580       return ConstIterator(*map, ItemIt(*graph));
   581     }
   582 
   583     /// It gives back the const iterator pointed to the first invalid element.
   584     ConstIterator end() const {
   585       return ConstIterator(*map, ItemIt(INVALID));
   586     }
   587 
   588   protected:
   589     
   590     const Map* map;
   591     const Graph * graph;
   592 
   593   public:
   594     // STL  compatibility typedefs.
   595     typedef Value value_type;
   596     typedef ConstIterator const_iterator;
   597     typedef ConstReference const_reference;
   598     typedef ConstPointer const_pointer;
   599     typedef int difference_type;
   600   };
   601 
   602 
   603   /** This class makes from a map an iteratable set
   604    *  which contains all the values of the map.
   605    *  The values can be modified.
   606    */
   607   template <typename _Graph, typename _Item, typename _Map>
   608   class MapValueSet {
   609 
   610   public:
   611     
   612     typedef _Graph Graph;
   613     typedef _Item Item;
   614     typedef _Map Map;
   615 
   616   protected:
   617 
   618     /// The iterator to iterate on the keys.
   619     typedef typename ItemSetTraits<Graph, Item>::ItemIt ItemIt;
   620 
   621   public:
   622 
   623     /// The map initialized const value set.
   624     MapValueSet(const Graph& _graph, Map& _map) 
   625       : map(&_map), graph(&_graph) {}
   626 
   627     /// The const iterator of the set.
   628     typedef MapValueIterator<_Graph, _Item, _Map> Iterator;
   629     /// The const iterator of the set.
   630     typedef MapConstValueIterator<_Graph, _Item, _Map> ConstIterator;
   631 
   632     typedef typename ConstIterator::Value Value;
   633     typedef typename Iterator::Reference Reference;
   634     typedef typename Iterator::Pointer Pointer;
   635     typedef typename ConstIterator::Reference ConstReference;
   636     typedef typename ConstIterator::Pointer ConstPointer;
   637 
   638     /// It gives back the const iterator pointed to the first element.
   639     ConstIterator begin() const {
   640       return ConstIterator(*map, ItemIt(*graph));
   641     }
   642 
   643     /// It gives back the const iterator pointed to the first invalid element.
   644     ConstIterator end() const {
   645       return ConstIterator(*map, ItemIt(INVALID));
   646     }
   647 
   648     /// It gives back the iterator pointed to the first element.
   649     Iterator begin() {
   650       return Iterator(*map, ItemIt(*graph));
   651     }
   652 
   653     /// It gives back the iterator pointed to the first invalid element.
   654     Iterator end() {
   655       return Iterator(*map, ItemIt(INVALID));
   656     }
   657 
   658   protected:
   659     
   660     Map* map;
   661     const Graph * graph;
   662 
   663   public:
   664     // STL  compatibility typedefs.
   665     typedef Value value_type;
   666     typedef Iterator iterator;
   667     typedef ConstIterator const_iterator;
   668     typedef Reference reference;
   669     typedef ConstReference const_reference;
   670     typedef Pointer pointer;
   671     typedef ConstPointer const_pointer;
   672     typedef int difference_type;
   673 
   674   };
   675 
   676   /** This class makes from a map an iteratable set
   677    *  which contains all the values of the map.
   678    *  The values can be modified.
   679    */
   680   template <
   681     typename _Graph, 
   682     typename _Item,
   683     typename _Map
   684     >
   685   class MapSet {
   686   public:    
   687 
   688     typedef _Graph Graph;
   689     typedef _Item Item;
   690     typedef _Map Map;
   691 
   692   protected:
   693 
   694     typedef typename ItemSetTraits<_Graph, _Item>::ItemIt ItemIt;
   695 
   696   public:
   697 
   698     /// The map initialized value set.
   699     MapSet(const Graph& _graph, Map& _map) : graph(&_graph), map(&_map) {}
   700 
   701     /// The const iterator of the set.
   702     typedef MapIterator<_Graph, _Item, _Map> Iterator;
   703     typedef MapConstIterator<_Graph, _Item, _Map> ConstIterator;
   704 
   705     typedef typename ConstIterator::Value Value;
   706     typedef typename Iterator::Reference Reference;
   707     typedef typename Iterator::Pointer Pointer;
   708     typedef typename ConstIterator::Reference ConstReference;
   709     typedef typename ConstIterator::Pointer ConstPointer;
   710 
   711 
   712     /// It gives back the const iterator pointed to the first element.
   713     ConstIterator begin() const {
   714       return ConstIterator(*map, ItemIt(*graph));
   715     }
   716 
   717     /// It gives back the const iterator pointed to the first invalid element.
   718     ConstIterator end() const {
   719       return ConstIterator(*map, ItemIt(INVALID));
   720     }
   721 
   722     /// The iterator of the set.
   723 
   724     /// It gives back the iterator pointed to the first element.
   725     Iterator begin() {
   726       return Iterator(*map, ItemIt(*graph));
   727     }
   728 
   729     /// It gives back the iterator pointed to the first invalid element.
   730     Iterator end() {
   731       return Iterator(*map, ItemIt(INVALID));
   732     }
   733 
   734   protected:
   735     
   736     const Graph* graph;
   737     Map* map;
   738             
   739   public:
   740     // STL  compatibility typedefs.
   741     typedef Value value_type;
   742     typedef Iterator iterator;
   743     typedef ConstIterator const_iterator;
   744     typedef Reference reference;
   745     typedef ConstReference const_reference;
   746     typedef Pointer pointer;
   747     typedef ConstPointer const_pointer;
   748     typedef int difference_type;
   749 
   750   };
   751 
   752   template <
   753     typename _Graph, 
   754     typename _Item,
   755     typename _Map
   756     >
   757   class ConstMapSet {
   758     
   759     typedef _Graph Graph;
   760     typedef _Map Map;
   761 
   762     const Graph* graph;
   763     const Map* map;
   764 
   765   public:
   766 
   767     typedef typename ItemSetTraits<_Graph, _Item>::ItemIt ItemIt;
   768 
   769 
   770     /// The map initialized value set.
   771     ConstMapSet(const Graph& _graph, const Map& _map) 
   772       : graph(&_graph), map(&_map) {}
   773 
   774     /// The const iterator of the set.
   775     typedef MapConstIterator<_Graph, _Item, _Map> ConstIterator;
   776 
   777     typedef typename ConstIterator::Value Value;
   778     typedef typename ConstIterator::Reference ConstReference;
   779     typedef typename ConstIterator::Pointer ConstPointer;
   780 
   781 
   782     /// It gives back the const iterator pointed to the first element.
   783     ConstIterator begin() const {
   784       return ConstIterator(*map, ItemIt(*graph));
   785     }
   786 
   787     /// It gives back the const iterator pointed to the first invalid element.
   788     ConstIterator end() const {
   789       return ConstIterator(*map, ItemIt(INVALID));
   790     }
   791             
   792   public:
   793     // STL  compatibility typedefs.
   794     typedef Value value_type;
   795     typedef ConstIterator const_iterator;
   796     typedef ConstReference const_reference;
   797     typedef ConstPointer const_pointer;
   798     typedef int difference_type;
   799 
   800   };
   801 
   802   template <typename _Map>
   803   class IterableMapExtender : public _Map {
   804   public:
   805 
   806     typedef _Map Parent;
   807     typedef Parent Map;
   808     typedef typename Map::Graph Graph;
   809     typedef typename Map::Key Item;
   810     typedef typename Map::Value Value;
   811 
   812     typedef MapSet<Graph, Item, Map> MapSet;
   813 
   814     IterableMapExtender() : Parent() {}
   815 
   816     IterableMapExtender(const Graph& graph) : Parent(graph) {}
   817 
   818     IterableMapExtender(const Graph& graph, const Value& value) 
   819       : Parent(graph, value) {}
   820 
   821     MapSet mapSet() { 
   822       return MapSet(*Parent::getGraph(), *this); 
   823     }
   824 
   825     typedef ConstMapSet<Graph, Item, Map> ConstMapSet;
   826 
   827     ConstMapSet mapSet() const { 
   828       return ConstMapSet(*Parent::getGraph(), *this); 
   829     }
   830 
   831     typedef MapConstKeySet<Graph, Item> ConstKeySet;
   832  
   833     ConstKeySet keySet() const {
   834       return ConstKeySet(*Parent::getGraph());
   835     }
   836 
   837     typedef MapValueSet<Graph, Item, Map> ValueSet;
   838  
   839     ValueSet valueSet() {
   840       return ValueSet(*Parent::getGraph(), *this);
   841     }
   842 
   843     typedef MapConstValueSet<Graph, Item, Map> ConstValueSet;
   844  
   845     ConstValueSet valueSet() const {
   846       return ConstValueSet(*Parent::getGraph(), *this);
   847     }
   848 
   849   };
   850 
   851   /// @}
   852 
   853 }
   854 
   855 #endif