lemon/maps.h
author alpar
Thu, 26 May 2005 16:32:26 +0000
changeset 1439 2c43106bef85
parent 1435 8e85e6bbefdf
child 1456 5289afbdb720
permissions -rw-r--r--
Revome duplicated typedefs
     1 /* -*- C++ -*-
     2  * lemon/maps.h - Part of LEMON, a generic C++ optimization library
     3  *
     4  * Copyright (C) 2005 Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport
     5  * (Egervary Research Group on Combinatorial Optimization, 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_MAPS_H
    18 #define LEMON_MAPS_H
    19 
    20 #include <lemon/graph_utils.h>
    21 #include <lemon/utility.h>
    22 
    23 
    24 ///\file
    25 ///\ingroup maps
    26 ///\brief Miscellaneous property maps
    27 ///
    28 ///\todo This file has the same name as the concept file in concept/,
    29 /// and this is not easily detectable in docs...
    30 
    31 #include <map>
    32 
    33 namespace lemon {
    34 
    35   /// \addtogroup maps
    36   /// @{
    37 
    38   /// Base class of maps.
    39 
    40   /// Base class of maps.
    41   /// It provides the necessary <tt>typedef</tt>s required by the map concept.
    42   template<typename K, typename T>
    43   class MapBase
    44   {
    45   public:
    46     ///\e
    47     typedef K Key;
    48     ///\e
    49     typedef T Value;
    50   };
    51 
    52   /// Null map. (a.k.a. DoNothingMap)
    53 
    54   /// If you have to provide a map only for its type definitions,
    55   /// or if you have to provide a writable map, but
    56   /// data written to it will sent to <tt>/dev/null</tt>...
    57   template<typename K, typename T>
    58   class NullMap : public MapBase<K,T>
    59   {
    60   public:
    61     
    62     typedef True NeedCopy;
    63 
    64     /// Gives back a default constructed element.
    65     T operator[](const K&) const { return T(); }
    66     /// Absorbs the value.
    67     void set(const K&, const T&) {}
    68   };
    69 
    70   template <typename K, typename V> 
    71   NullMap<K, V> nullMap() {
    72     return NullMap<K, V>();
    73   }
    74 
    75 
    76   /// Constant map.
    77 
    78   /// This is a readable map which assigns a specified value to each key.
    79   /// In other aspects it is equivalent to the \ref NullMap.
    80   /// \todo set could be used to set the value.
    81   template<typename K, typename T>
    82   class ConstMap : public MapBase<K,T>
    83   {
    84     T v;
    85   public:
    86 
    87     typedef True NeedCopy;
    88 
    89     /// Default constructor
    90 
    91     /// The value of the map will be uninitialized. 
    92     /// (More exactly it will be default constructed.)
    93     ConstMap() {}
    94     ///\e
    95 
    96     /// \param _v The initial value of the map.
    97     ///
    98     ConstMap(const T &_v) : v(_v) {}
    99 
   100     T operator[](const K&) const { return v; }
   101     void set(const K&, const T&) {}
   102 
   103     template<typename T1>
   104     struct rebind {
   105       typedef ConstMap<K,T1> other;
   106     };
   107 
   108     template<typename T1>
   109     ConstMap(const ConstMap<K,T1> &, const T &_v) : v(_v) {}
   110   };
   111 
   112   ///Returns a \ref ConstMap class
   113 
   114   ///This function just returns a \ref ConstMap class.
   115   ///\relates ConstMap
   116   template<class V,class K> 
   117   inline ConstMap<V,K> constMap(const K &k) 
   118   {
   119     return ConstMap<V,K>(k);
   120   }
   121 
   122 
   123   //to document later
   124   template<typename T, T v>
   125   struct Const { };
   126   //to document later
   127   template<typename K, typename V, V v>
   128   class ConstMap<K, Const<V, v> > : public MapBase<K, V>
   129   {
   130   public:
   131     ConstMap() { }
   132     V operator[](const K&) const { return v; }
   133     void set(const K&, const V&) { }
   134   };
   135 
   136   /// \c std::map wrapper
   137 
   138   /// This is essentially a wrapper for \c std::map. With addition that
   139   /// you can specify a default value different from \c Value() .
   140   ///
   141   /// \todo Provide allocator parameter...
   142   template <typename K, typename T, typename Compare = std::less<K> >
   143   class StdMap : public std::map<K,T,Compare> {
   144     typedef std::map<K,T,Compare> parent;
   145     T v;
   146     typedef typename parent::value_type PairType;
   147 
   148   public:
   149     typedef K Key;
   150     typedef T Value;
   151     typedef T& Reference;
   152     typedef const T& ConstReference;
   153 
   154 
   155     StdMap() : v() {}
   156     /// Constructor with specified default value
   157     StdMap(const T& _v) : v(_v) {}
   158 
   159     /// \brief Constructs the map from an appropriate std::map.
   160     ///
   161     /// \warning Inefficient: copies the content of \c m !
   162     StdMap(const parent &m) : parent(m) {}
   163     /// \brief Constructs the map from an appropriate std::map, and explicitly
   164     /// specifies a default value.
   165     ///
   166     /// \warning Inefficient: copies the content of \c m !
   167     StdMap(const parent &m, const T& _v) : parent(m), v(_v) {}
   168     
   169     template<typename T1, typename Comp1>
   170     StdMap(const StdMap<Key,T1,Comp1> &m, const T &_v) { 
   171       //FIXME; 
   172     }
   173 
   174     Reference operator[](const Key &k) {
   175       return insert(PairType(k,v)).first -> second;
   176     }
   177     ConstReference operator[](const Key &k) const {
   178       typename parent::iterator i = lower_bound(k);
   179       if (i == parent::end() || parent::key_comp()(k, (*i).first))
   180 	return v;
   181       return (*i).second;
   182     }
   183     void set(const Key &k, const T &t) {
   184       parent::operator[](k) = t;
   185     }
   186 
   187     /// Changes the default value of the map.
   188     /// \return Returns the previous default value.
   189     ///
   190     /// \warning The value of some keys (which has already been queried, but
   191     /// the value has been unchanged from the default) may change!
   192     T setDefault(const T &_v) { T old=v; v=_v; return old; }
   193 
   194     template<typename T1>
   195     struct rebind {
   196       typedef StdMap<Key,T1,Compare> other;
   197     };
   198   };
   199 
   200   /// @}
   201 
   202   /// \addtogroup map_adaptors
   203   /// @{
   204 
   205 
   206   ///Convert the \c Value of a maps to another type.
   207 
   208   ///This \ref concept::ReadMap "read only map"
   209   ///converts the \c Value of a maps to type \c T.
   210   ///Its \c Value is inherited from \c M.
   211   ///
   212   ///Actually,
   213   ///\code
   214   ///  ConvertMap<X> sh(x,v);
   215   ///\endcode
   216   ///it is equivalent with
   217   ///\code
   218   ///  ConstMap<X::Key, X::Value> c_tmp(v);
   219   ///  AddMap<X, ConstMap<X::Key, X::Value> > sh(x,v);
   220   ///\endcode
   221   ///\bug wrong documentation
   222   template<class M, class T> 
   223   class ConvertMap {
   224     typename SmartConstReference<M>::Type m;
   225   public:
   226 
   227     typedef True NeedCopy;
   228 
   229     typedef typename M::Key Key;
   230     typedef T Value;
   231 
   232     ///Constructor
   233 
   234     ///Constructor
   235     ///\param _m is the undelying map
   236     ///\param _v is the convert value
   237     ConvertMap(const M &_m) : m(_m) {};
   238 
   239     /// \brief The subscript operator.
   240     ///
   241     /// The subscript operator.
   242     /// \param edge The edge 
   243     /// \return The target of the edge 
   244     Value operator[](Key k) const {return m[k];}
   245   };
   246   
   247   ///Returns an \ref ConvertMap class
   248 
   249   ///This function just returns an \ref ConvertMap class.
   250   ///\relates ConvertMap
   251   ///\todo The order of the template parameters are changed.
   252   template<class T, class M>
   253   inline ConvertMap<M,T> convertMap(const M &m) 
   254   {
   255     return ConvertMap<M,T>(m);
   256   }
   257 
   258   ///Sum of two maps
   259 
   260   ///This \ref concept::ReadMap "read only map" returns the sum of the two
   261   ///given maps. Its \c Key and \c Value will be inherited from \c M1.
   262   ///The \c Key and \c Value of M2 must be convertible to those of \c M1.
   263 
   264   template<class M1,class M2> 
   265   class AddMap
   266   {
   267     typename SmartConstReference<M1>::Type m1;
   268     typename SmartConstReference<M2>::Type m2;
   269 
   270   public:
   271 
   272     typedef True NeedCopy;
   273 
   274     typedef typename M1::Key Key;
   275     typedef typename M1::Value Value;
   276 
   277     ///Constructor
   278 
   279     ///\e
   280     ///
   281     AddMap(const M1 &_m1,const M2 &_m2) : m1(_m1), m2(_m2) {};
   282     Value operator[](Key k) const {return m1[k]+m2[k];}
   283   };
   284   
   285   ///Returns an \ref AddMap class
   286 
   287   ///This function just returns an \ref AddMap class.
   288   ///\todo How to call these type of functions?
   289   ///
   290   ///\relates AddMap
   291   ///\todo Wrong scope in Doxygen when \c \\relates is used
   292   template<class M1,class M2> 
   293   inline AddMap<M1,M2> addMap(const M1 &m1,const M2 &m2) 
   294   {
   295     return AddMap<M1,M2>(m1,m2);
   296   }
   297 
   298   ///Shift a maps with a constant.
   299 
   300   ///This \ref concept::ReadMap "read only map" returns the sum of the
   301   ///given map and a constant value.
   302   ///Its \c Key and \c Value is inherited from \c M.
   303   ///
   304   ///Actually,
   305   ///\code
   306   ///  ShiftMap<X> sh(x,v);
   307   ///\endcode
   308   ///it is equivalent with
   309   ///\code
   310   ///  ConstMap<X::Key, X::Value> c_tmp(v);
   311   ///  AddMap<X, ConstMap<X::Key, X::Value> > sh(x,v);
   312   ///\endcode
   313   template<class M> 
   314   class ShiftMap
   315   {
   316     typename SmartConstReference<M>::Type m;
   317     typename M::Value v;
   318   public:
   319 
   320     typedef True NeedCopy;
   321     typedef typename M::Key Key;
   322     typedef typename M::Value Value;
   323 
   324     ///Constructor
   325 
   326     ///Constructor
   327     ///\param _m is the undelying map
   328     ///\param _v is the shift value
   329     ShiftMap(const M &_m,const Value &_v ) : m(_m), v(_v) {};
   330     Value operator[](Key k) const {return m[k]+v;}
   331   };
   332   
   333   ///Returns an \ref ShiftMap class
   334 
   335   ///This function just returns an \ref ShiftMap class.
   336   ///\relates ShiftMap
   337   ///\todo A better name is required.
   338   template<class M> 
   339   inline ShiftMap<M> shiftMap(const M &m,const typename M::Value &v) 
   340   {
   341     return ShiftMap<M>(m,v);
   342   }
   343 
   344   ///Difference of two maps
   345 
   346   ///This \ref concept::ReadMap "read only map" returns the difference
   347   ///of the values returned by the two
   348   ///given maps. Its \c Key and \c Value will be inherited from \c M1.
   349   ///The \c Key and \c Value of \c M2 must be convertible to those of \c M1.
   350 
   351   template<class M1,class M2> 
   352   class SubMap
   353   {
   354     typename SmartConstReference<M1>::Type m1;
   355     typename SmartConstReference<M2>::Type m2;
   356   public:
   357 
   358     typedef True NeedCopy;
   359     typedef typename M1::Key Key;
   360     typedef typename M1::Value Value;
   361 
   362     ///Constructor
   363 
   364     ///\e
   365     ///
   366     SubMap(const M1 &_m1,const M2 &_m2) : m1(_m1), m2(_m2) {};
   367     Value operator[](Key k) const {return m1[k]-m2[k];}
   368   };
   369   
   370   ///Returns a \ref SubMap class
   371 
   372   ///This function just returns a \ref SubMap class.
   373   ///
   374   ///\relates SubMap
   375   template<class M1,class M2> 
   376   inline SubMap<M1,M2> subMap(const M1 &m1,const M2 &m2) 
   377   {
   378     return SubMap<M1,M2>(m1,m2);
   379   }
   380 
   381   ///Product of two maps
   382 
   383   ///This \ref concept::ReadMap "read only map" returns the product of the
   384   ///values returned by the two
   385   ///given
   386   ///maps. Its \c Key and \c Value will be inherited from \c M1.
   387   ///The \c Key and \c Value of \c M2 must be convertible to those of \c M1.
   388 
   389   template<class M1,class M2> 
   390   class MulMap
   391   {
   392     typename SmartConstReference<M1>::Type m1;
   393     typename SmartConstReference<M2>::Type m2;
   394   public:
   395 
   396     typedef True NeedCopy;
   397     typedef typename M1::Key Key;
   398     typedef typename M1::Value Value;
   399 
   400     ///Constructor
   401 
   402     ///\e
   403     ///
   404     MulMap(const M1 &_m1,const M2 &_m2) : m1(_m1), m2(_m2) {};
   405     Value operator[](Key k) const {return m1[k]*m2[k];}
   406   };
   407   
   408   ///Returns a \ref MulMap class
   409 
   410   ///This function just returns a \ref MulMap class.
   411   ///\relates MulMap
   412   template<class M1,class M2> 
   413   inline MulMap<M1,M2> mulMap(const M1 &m1,const M2 &m2) 
   414   {
   415     return MulMap<M1,M2>(m1,m2);
   416   }
   417  
   418   ///Scale a maps with a constant.
   419 
   420   ///This \ref concept::ReadMap "read only map" returns the value of the
   421   ///given map multipied with a constant value.
   422   ///Its \c Key and \c Value is inherited from \c M.
   423   ///
   424   ///Actually,
   425   ///\code
   426   ///  ScaleMap<X> sc(x,v);
   427   ///\endcode
   428   ///it is equivalent with
   429   ///\code
   430   ///  ConstMap<X::Key, X::Value> c_tmp(v);
   431   ///  MulMap<X, ConstMap<X::Key, X::Value> > sc(x,v);
   432   ///\endcode
   433   template<class M> 
   434   class ScaleMap
   435   {
   436     typename SmartConstReference<M>::Type m;
   437     typename M::Value v;
   438   public:
   439 
   440     typedef True NeedCopy;
   441     typedef typename M::Key Key;
   442     typedef typename M::Value Value;
   443 
   444     ///Constructor
   445 
   446     ///Constructor
   447     ///\param _m is the undelying map
   448     ///\param _v is the scaling value
   449     ScaleMap(const M &_m,const Value &_v ) : m(_m), v(_v) {};
   450     Value operator[](Key k) const {return m[k]*v;}
   451   };
   452   
   453   ///Returns an \ref ScaleMap class
   454 
   455   ///This function just returns an \ref ScaleMap class.
   456   ///\relates ScaleMap
   457   ///\todo A better name is required.
   458   template<class M> 
   459   inline ScaleMap<M> scaleMap(const M &m,const typename M::Value &v) 
   460   {
   461     return ScaleMap<M>(m,v);
   462   }
   463 
   464   ///Quotient of two maps
   465 
   466   ///This \ref concept::ReadMap "read only map" returns the quotient of the
   467   ///values returned by the two
   468   ///given maps. Its \c Key and \c Value will be inherited from \c M1.
   469   ///The \c Key and \c Value of \c M2 must be convertible to those of \c M1.
   470 
   471   template<class M1,class M2> 
   472   class DivMap
   473   {
   474     typename SmartConstReference<M1>::Type m1;
   475     typename SmartConstReference<M2>::Type m2;
   476   public:
   477 
   478     typedef True NeedCopy;
   479     typedef typename M1::Key Key;
   480     typedef typename M1::Value Value;
   481 
   482     ///Constructor
   483 
   484     ///\e
   485     ///
   486     DivMap(const M1 &_m1,const M2 &_m2) : m1(_m1), m2(_m2) {};
   487     Value operator[](Key k) const {return m1[k]/m2[k];}
   488   };
   489   
   490   ///Returns a \ref DivMap class
   491 
   492   ///This function just returns a \ref DivMap class.
   493   ///\relates DivMap
   494   template<class M1,class M2> 
   495   inline DivMap<M1,M2> divMap(const M1 &m1,const M2 &m2) 
   496   {
   497     return DivMap<M1,M2>(m1,m2);
   498   }
   499   
   500   ///Composition of two maps
   501 
   502   ///This \ref concept::ReadMap "read only map" returns the composition of
   503   ///two
   504   ///given maps. That is to say, if \c m1 is of type \c M1 and \c m2 is
   505   ///of \c M2,
   506   ///then for
   507   ///\code
   508   ///  ComposeMap<M1,M2> cm(m1,m2);
   509   ///\endcode
   510   /// <tt>cm[x]</tt> will be equal to <tt>m1[m2[x]]</tt>
   511   ///
   512   ///Its \c Key is inherited from \c M2 and its \c Value is from
   513   ///\c M1.
   514   ///The \c M2::Value must be convertible to \c M1::Key.
   515   ///\todo Check the requirements.
   516 
   517   template<class M1,class M2> 
   518   class ComposeMap
   519   {
   520     typename SmartConstReference<M1>::Type m1;
   521     typename SmartConstReference<M2>::Type m2;
   522   public:
   523 
   524     typedef True NeedCopy;
   525     typedef typename M2::Key Key;
   526     typedef typename M1::Value Value;
   527 
   528     ///Constructor
   529 
   530     ///\e
   531     ///
   532     ComposeMap(const M1 &_m1,const M2 &_m2) : m1(_m1), m2(_m2) {};
   533     Value operator[](Key k) const {return m1[m2[k]];}
   534   };
   535   ///Returns a \ref ComposeMap class
   536 
   537   ///This function just returns a \ref ComposeMap class.
   538   ///
   539   ///\relates ComposeMap
   540   template<class M1,class M2> 
   541   inline ComposeMap<M1,M2> composeMap(const M1 &m1,const M2 &m2) 
   542   {
   543     return ComposeMap<M1,M2>(m1,m2);
   544   }
   545   
   546   ///Combine of two maps using an STL (binary) functor.
   547 
   548   ///Combine of two maps using an STL (binary) functor.
   549   ///
   550   ///
   551   ///This \ref concept::ReadMap "read only map" takes to maps and a
   552   ///binary functor and returns the composition of
   553   ///two
   554   ///given maps unsing the functor. 
   555   ///That is to say, if \c m1 and \c m2 is of type \c M1 and \c M2
   556   ///and \c f is of \c F,
   557   ///then for
   558   ///\code
   559   ///  CombineMap<M1,M2,F,V> cm(m1,m2,f);
   560   ///\endcode
   561   /// <tt>cm[x]</tt> will be equal to <tt>f(m1[x],m2[x])</tt>
   562   ///
   563   ///Its \c Key is inherited from \c M1 and its \c Value is \c V.
   564   ///The \c M2::Value and \c M1::Value must be convertible to the corresponding
   565   ///input parameter of \c F and the return type of \c F must be convertible
   566   ///to \c V.
   567   ///\todo Check the requirements.
   568 
   569   template<class M1,class M2,class F,class V = typename F::result_type> 
   570   class CombineMap
   571   {
   572     typename SmartConstReference<M1>::Type m1;
   573     typename SmartConstReference<M2>::Type m2;
   574     F f;
   575   public:
   576 
   577     typedef True NeedCopy;
   578     typedef typename M1::Key Key;
   579     typedef V Value;
   580 
   581     ///Constructor
   582 
   583     ///\e
   584     ///
   585     CombineMap(const M1 &_m1,const M2 &_m2,const F &_f)
   586       : m1(_m1), m2(_m2), f(_f) {};
   587     Value operator[](Key k) const {return f(m1[k],m2[k]);}
   588   };
   589   
   590   ///Returns a \ref CombineMap class
   591 
   592   ///This function just returns a \ref CombineMap class.
   593   ///
   594   ///Only the first template parameter (the value type) must be given.
   595   ///
   596   ///For example if \c m1 and \c m2 are both \c double valued maps, then 
   597   ///\code
   598   ///combineMap<double>(m1,m2,std::plus<double>)
   599   ///\endcode
   600   ///is equivalent with
   601   ///\code
   602   ///addMap(m1,m2)
   603   ///\endcode
   604   ///
   605   ///\relates CombineMap
   606   template<class M1,class M2,class F> 
   607   inline CombineMap<M1,M2,F> combineMap(const M1 &m1,const M2 &m2,const F &f) 
   608   {
   609     return CombineMap<M1,M2,F>(m1,m2,f);
   610   }
   611 
   612   ///Negative value of a map
   613 
   614   ///This \ref concept::ReadMap "read only map" returns the negative
   615   ///value of the
   616   ///value returned by the
   617   ///given map. Its \c Key and \c Value will be inherited from \c M.
   618   ///The unary \c - operator must be defined for \c Value, of course.
   619 
   620   template<class M> 
   621   class NegMap
   622   {
   623     typename SmartConstReference<M>::Type m;
   624   public:
   625 
   626     typedef True NeedCopy;
   627     typedef typename M::Key Key;
   628     typedef typename M::Value Value;
   629 
   630     ///Constructor
   631 
   632     ///\e
   633     ///
   634     NegMap(const M &_m) : m(_m) {};
   635     Value operator[](Key k) const {return -m[k];}
   636   };
   637   
   638   ///Returns a \ref NegMap class
   639 
   640   ///This function just returns a \ref NegMap class.
   641   ///\relates NegMap
   642   template<class M> 
   643   inline NegMap<M> negMap(const M &m) 
   644   {
   645     return NegMap<M>(m);
   646   }
   647 
   648 
   649   ///Absolute value of a map
   650 
   651   ///This \ref concept::ReadMap "read only map" returns the absolute value
   652   ///of the
   653   ///value returned by the
   654   ///given map. Its \c Key and \c Value will be inherited
   655   ///from <tt>M</tt>. <tt>Value</tt>
   656   ///must be comparable to <tt>0</tt> and the unary <tt>-</tt>
   657   ///operator must be defined for it, of course.
   658   ///
   659   ///\bug We need a unified way to handle the situation below:
   660   ///\code
   661   ///  struct _UnConvertible {};
   662   ///  template<class A> inline A t_abs(A a) {return _UnConvertible();}
   663   ///  template<> inline int t_abs<>(int n) {return abs(n);}
   664   ///  template<> inline long int t_abs<>(long int n) {return labs(n);}
   665   ///  template<> inline long long int t_abs<>(long long int n) {return ::llabs(n);}
   666   ///  template<> inline float t_abs<>(float n) {return fabsf(n);}
   667   ///  template<> inline double t_abs<>(double n) {return fabs(n);}
   668   ///  template<> inline long double t_abs<>(long double n) {return fabsl(n);}
   669   ///\endcode
   670   
   671 
   672   template<class M> 
   673   class AbsMap
   674   {
   675     typename SmartConstReference<M>::Type m;
   676   public:
   677 
   678     typedef True NeedCopy;
   679     typedef typename M::Key Key;
   680     typedef typename M::Value Value;
   681 
   682     ///Constructor
   683 
   684     ///\e
   685     ///
   686     AbsMap(const M &_m) : m(_m) {};
   687     Value operator[](Key k) const {Value tmp=m[k]; return tmp>=0?tmp:-tmp;}
   688   };
   689   
   690   ///Returns a \ref AbsMap class
   691 
   692   ///This function just returns a \ref AbsMap class.
   693   ///\relates AbsMap
   694   template<class M> 
   695   inline AbsMap<M> absMap(const M &m) 
   696   {
   697     return AbsMap<M>(m);
   698   }
   699 
   700   ///Converts an STL style functor to a map
   701 
   702   ///This \ref concept::ReadMap "read only map" returns the value
   703   ///of a
   704   ///given map.
   705   ///
   706   ///Template parameters \c K and \c V will become its
   707   ///\c Key and \c Value. They must be given explicitely
   708   ///because a functor does not provide such typedefs.
   709   ///
   710   ///Parameter \c F is the type of the used functor.
   711   
   712 
   713   template<class K,class V,class F> 
   714   class FunctorMap
   715   {
   716     const F &f;
   717   public:
   718 
   719     typedef True NeedCopy;
   720     typedef K Key;
   721     typedef V Value;
   722 
   723     ///Constructor
   724 
   725     ///\e
   726     ///
   727     FunctorMap(const F &_f) : f(_f) {};
   728     Value operator[](Key k) const {return f(k);}
   729   };
   730   
   731   ///Returns a \ref FunctorMap class
   732 
   733   ///This function just returns a \ref FunctorMap class.
   734   ///
   735   ///The third template parameter isn't necessary to be given.
   736   ///\relates FunctorMap
   737   template<class K,class V, class F>
   738   inline FunctorMap<K,V,F> functorMap(const F &f) 
   739   {
   740     return FunctorMap<K,V,F>(f);
   741   }
   742 
   743   ///Converts a map to an STL style (unary) functor
   744 
   745   ///This class Converts a map to an STL style (unary) functor.
   746   ///that is it provides an <tt>operator()</tt> to read its values.
   747   ///
   748   ///For the sake of convenience it also works as
   749   ///a ususal \ref concept::ReadMap "readable map", i.e
   750   ///<tt>operator[]</tt> and the \c Key and \c Value typedefs also exist.
   751 
   752   template<class M> 
   753   class MapFunctor
   754   {
   755     typename SmartConstReference<M>::Type m;
   756   public:
   757 
   758     typedef True NeedCopy;
   759     typedef typename M::Key argument_type;
   760     typedef typename M::Value result_type;
   761     typedef typename M::Key Key;
   762     typedef typename M::Value Value;
   763 
   764     ///Constructor
   765 
   766     ///\e
   767     ///
   768     MapFunctor(const M &_m) : m(_m) {};
   769     ///Returns a value of the map
   770     
   771     ///\e
   772     ///
   773     Value operator()(Key k) const {return m[k];}
   774     ///\e
   775     ///
   776     Value operator[](Key k) const {return m[k];}
   777   };
   778   
   779   ///Returns a \ref MapFunctor class
   780 
   781   ///This function just returns a \ref MapFunctor class.
   782   ///\relates MapFunctor
   783   template<class M> 
   784   inline MapFunctor<M> mapFunctor(const M &m) 
   785   {
   786     return MapFunctor<M>(m);
   787   }
   788 
   789 
   790   ///Apply all map setting operations to two maps
   791 
   792   ///This map has two \ref concept::WriteMap "writable map"
   793   ///parameters and each write request will be passed to both of them.
   794   ///If \c M1 is also \ref concept::ReadMap "readable",
   795   ///then the read operations will return the
   796   ///corresponding values of \c M1.
   797   ///
   798   ///The \c Key and \c Value will be inherited from \c M1.
   799   ///The \c Key and \c Value of M2 must be convertible from those of \c M1.
   800 
   801   template<class M1,class M2> 
   802   class ForkMap
   803   {
   804     typename SmartConstReference<M1>::Type m1;
   805     typename SmartConstReference<M2>::Type m2;
   806   public:
   807 
   808     typedef True NeedCopy;
   809     typedef typename M1::Key Key;
   810     typedef typename M1::Value Value;
   811 
   812     ///Constructor
   813 
   814     ///\e
   815     ///
   816     ForkMap(const M1 &_m1,const M2 &_m2) : m1(_m1), m2(_m2) {};
   817     Value operator[](Key k) const {return m1[k];}
   818     void set(Key k,const Value &v) {m1.set(k,v); m2.set(k,v);}
   819   };
   820   
   821   ///Returns an \ref ForkMap class
   822 
   823   ///This function just returns an \ref ForkMap class.
   824   ///\todo How to call these type of functions?
   825   ///
   826   ///\relates ForkMap
   827   ///\todo Wrong scope in Doxygen when \c \\relates is used
   828   template<class M1,class M2> 
   829   inline ForkMap<M1,M2> forkMap(const M1 &m1,const M2 &m2) 
   830   {
   831     return ForkMap<M1,M2>(m1,m2);
   832   }
   833 
   834   /// @}
   835   
   836 }
   837 
   838 
   839 #endif // LEMON_MAPS_H