/* -*- C++ -*-

  * src/lemon/maps.h - Part of LEMON, a generic C++ optimization library

  *

  * Copyright (C) 2004 Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport

  * (Egervary Combinatorial Optimization Research Group, EGRES).

  *

  * Permission to use, modify and distribute this software is granted

  * provided that this copyright notice appears in all copies. For

  * precise terms see the accompanying LICENSE file.

  *

  * This software is provided "AS IS" with no warranty of any kind,

  * express or implied, and with no claim as to its suitability for any

  * purpose.

  *

  */

 #ifndef LEMON_MAPS_H

 #define LEMON_MAPS_H

 ///\file

 ///\brief Miscellaneous property maps

 ///

 ///\todo This file has the same name as the concept file in concept/,

 /// and this is not easily detectable in docs...

 #include <map>

 namespace lemon {

   /// Base class of maps.

   /// Base class of maps.

   /// It provides the necessary <tt>typedef</tt>s required by the map concept.

   template<typename K, typename T>

   class MapBase

   {

   public:

     ///\e

     typedef K Key;

     ///\e

     typedef T Value;

   };

   /// Null map. (a.k.a. DoNothingMap)

   /// If you have to provide a map only for its type definitions,

   /// or if you have to provide a writable map, but

   /// data written to it will sent to <tt>/dev/null</tt>...

   template<typename K, typename T>

   class NullMap : public MapBase<K,T>

   {

   public:

     /// Gives back a default constructed element.

     T operator[](const K&) const { return T(); }

     /// Absorbs the value.

     void set(const K&, const T&) {}

   };

   /// Constant map.

   /// This is a readable map which assigns a specified value to each key.

   /// In other aspects it is equivalent to the \ref NullMap.

   /// \todo set could be used to set the value.

   template<typename K, typename T>

   class ConstMap : public MapBase<K,T>

   {

     T v;

   public:

     /// Default constructor

     /// The value of the map will be uninitialized. 

     /// (More exactly it will be default constructed.)

     ConstMap() {}

     ///\e

     /// \param _v The initial value of the map.

     ///

     ConstMap(const T &_v) : v(_v) {}

     T operator[](const K&) const { return v; }

     void set(const K&, const T&) {}

     template<typename T1>

     struct rebind {

       typedef ConstMap<K,T1> other;

     };

     template<typename T1>

     ConstMap(const ConstMap<K,T1> &, const T &_v) : v(_v) {}

   };

   //to document later

   template<typename T, T v>

   struct Const { };

   //to document later

   template<typename K, typename V, V v>

   class ConstMap<K, Const<V, v> > : public MapBase<K, V>

   {

   public:

     ConstMap() { }

     V operator[](const K&) const { return v; }

     void set(const K&, const V&) { }

   };

   /// \c std::map wrapper

   /// This is essentially a wrapper for \c std::map. With addition that

   /// you can specify a default value different from \c Value() .

   ///

   /// \todo Provide allocator parameter...

   template <typename K, typename T, typename Compare = std::less<K> >

   class StdMap : public std::map<K,T,Compare> {

     typedef std::map<K,T,Compare> parent;

     T v;

     typedef typename parent::value_type PairType;

   public:

     typedef K Key;

     typedef T Value;

     typedef T& Reference;

     typedef const T& ConstReference;

     StdMap() : v() {}

     /// Constructor with specified default value

     StdMap(const T& _v) : v(_v) {}

     /// \brief Constructs the map from an appropriate std::map.

     ///

     /// \warning Inefficient: copies the content of \c m !

     StdMap(const parent &m) : parent(m) {}

     /// \brief Constructs the map from an appropriate std::map, and explicitly

     /// specifies a default value.

     ///

     /// \warning Inefficient: copies the content of \c m !

     StdMap(const parent &m, const T& _v) : parent(m), v(_v) {}

     template<typename T1, typename Comp1>

     StdMap(const StdMap<Key,T1,Comp1> &m, const T &_v) { 

       //FIXME; 

     }

     Reference operator[](const Key &k) {

       return insert(PairType(k,v)).first -> second;

     }

     ConstReference operator[](const Key &k) const {

       typename parent::iterator i = lower_bound(k);

       if (i == parent::end() || parent::key_comp()(k, (*i).first))

 	return v;

       return (*i).second;

     }

     void set(const Key &k, const T &t) {

       parent::operator[](k) = t;

     }

     /// Changes the default value of the map.

     /// \return Returns the previous default value.

     ///

     /// \warning The value of some keys (which has already been queried, but

     /// the value has been unchanged from the default) may change!

     T setDefault(const T &_v) { T old=v; v=_v; return old; }

     template<typename T1>

     struct rebind {

       typedef StdMap<Key,T1,Compare> other;

     };

   };

 }

 #endif // LEMON_MAPS_H