/* -*- C++ -*-

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

  *

  * Copyright (C) 2005 Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport

  * (Egervary Research Group on Combinatorial Optimization, 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_CONCEPT_MAPS_H

 #define LEMON_CONCEPT_MAPS_H

 #include <lemon/utility.h>

 #include <lemon/concept_check.h>

 ///\ingroup concept

 ///\file

 ///\brief Map concepts checking classes for testing and documenting.

 namespace lemon {

   namespace concept {

     /// \addtogroup concept

     /// @{

     /// Readable map concept

     template<typename K, typename T>

     class ReadMap

     {

     public:

       /// Map's key type.

       typedef K Key;    

       /// Map's value type. (The type of objects associated with the keys).

       typedef T Value;

       // \bug Value don't need to be default constructible.

       /// Returns the value associated with a key.

       Value operator[](const Key &) const {return Value();}

       template<typename _ReadMap>

       struct Constraints {

 	void constraints() {

 	  Value val = m[key];

 	  val = m[key];

 	  typename _ReadMap::Value own_val = m[own_key]; 

 	  own_val = m[own_key]; 

 	  ignore_unused_variable_warning(val);

 	  ignore_unused_variable_warning(own_val);

 	  ignore_unused_variable_warning(key);

 	}

 	Key& key;

 	typename _ReadMap::Key& own_key;

 	_ReadMap& m;

       };

     };

     /// Writable map concept

     template<typename K, typename T>

     class WriteMap

     {

     public:

       /// Map's key type.

       typedef K Key;    

       /// Map's value type. (The type of objects associated with the keys).

       typedef T Value;

       /// Sets the value associated with a key.

       void set(const Key &,const Value &) {}

       ///Default constructor

       WriteMap() {}

       template <typename _WriteMap>

       struct Constraints {

 	void constraints() {

 	  // No constraints for constructor.

 	  m.set(key, val);

 	  m.set(own_key, own_val);

 	  ignore_unused_variable_warning(key);

 	  ignore_unused_variable_warning(val);

 	  ignore_unused_variable_warning(own_key);

 	  ignore_unused_variable_warning(own_val);

 	}

 	Value& val;

 	typename _WriteMap::Value own_val;

 	Key& key;

 	typename _WriteMap::Key& own_key;

 	_WriteMap& m;

       };

     };

     ///Read/Writable map concept

     template<typename K, typename T>

     class ReadWriteMap : public ReadMap<K,T>,

 			    public WriteMap<K,T>

     {

     public:

       /// Map's key type.

       typedef K Key;    

       /// Map's value type. (The type of objects associated with the keys).

       typedef T Value;

       /// Returns the value associated with a key.

       Value operator[](const Key &) const {return Value();}

       /// Sets the value associated with a key.

       void set(const Key & ,const Value &) {}

       template<typename _ReadWriteMap>

       struct Constraints {

 	void constraints() {

 	  checkConcept<ReadMap<K, T>, _ReadWriteMap >();

 	  checkConcept<WriteMap<K, T>, _ReadWriteMap >();

 	}

       };

     };

     ///Dereferable map concept

     template<typename K, typename T, typename R, typename CR>

     class ReferenceMap : public ReadWriteMap<K,T>

     {

     public:

       /// Tag for reference maps.

       typedef True ReferenceMapTag;

       /// Map's key type.

       typedef K Key;    

       /// Map's value type. (The type of objects associated with the keys).

       typedef T Value;

       /// Map's reference type.

       typedef R Reference;

       /// Map's const reference type.

       typedef CR ConstReference;

     protected:

       Value tmp;

     public:

       ///Returns a reference to the value associated to a key.

       Reference operator[](const Key &) { return tmp; }

       ///Returns a const reference to the value associated to a key.

       ConstReference operator[](const Key &) const

       { return tmp; }

       /// Sets the value associated with a key.

       void set(const Key &k,const Value &t) { operator[](k)=t; }

       // \todo rethink this concept

       template<typename _ReferenceMap>

       struct ReferenceMapConcept {

 	void constraints() {

 	  checkConcept<ReadWriteMap, _ReferenceMap >();

 	  m[key] = val;

 	  val  = m[key];

 	  m[key] = ref;

 	  ref = m[key];

 	  m[own_key] = own_val;

 	  own_val  = m[own_key];

 	  m[own_key] = own_ref;

 	  own_ref = m[own_key];	  	  

 	}

 	typename _ReferenceMap::Key& own_key;

 	typename _ReferenceMap::Value& own_val;

 	typename _ReferenceMap::Reference& own_ref;

 	Key& key;

 	Value& val;

 	Reference& ref;

 	_ReferenceMap& m;

       };

     };

     // @}

   } //namespace concept

 } //namespace lemon

 #endif // LEMON_CONCEPT_MAPS_H