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/* -*- mode: C++; indent-tabs-mode: nil; -*-
 *
 * This file is a part of LEMON, a generic C++ optimization library.
 *
 * Copyright (C) 2003-2009
 * 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_CONCEPTS_MAPS_H
#define LEMON_CONCEPTS_MAPS_H

#include <lemon/core.h>
#include <lemon/concept_check.h>

///\ingroup map_concepts
///\file
///\brief The concept of maps.

namespace lemon {

  namespace concepts {

    /// \addtogroup map_concepts
    /// @{

    /// Readable map concept

    /// Readable map concept.
    ///
    template<typename K, typename T>
    class ReadMap
    {
    public:
      /// The key type of the map.
      typedef K Key;
      /// \brief The value type of the map.
      /// (The type of objects associated with the keys).
      typedef T Value;

      /// Returns the value associated with the given key.
      Value operator[](const Key &) const {
        return *static_cast<Value *>(0);
      }

      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(key);
          ignore_unused_variable_warning(val);
          ignore_unused_variable_warning(own_key);
          ignore_unused_variable_warning(own_val);
        }
        const Key& key;
        const typename _ReadMap::Key& own_key;
        const _ReadMap& m;
        Constraints() {}
      };

    };


    /// Writable map concept

    /// Writable map concept.
    ///
    template<typename K, typename T>
    class WriteMap
    {
    public:
      /// The key type of the map.
      typedef K Key;
      /// \brief The value type of the map.
      /// (The type of objects associated with the keys).
      typedef T Value;

      /// Sets the value associated with the given key.
      void set(const Key &, const Value &) {}

      /// Default constructor.
      WriteMap() {}

      template <typename _WriteMap>
      struct Constraints {
        void constraints() {
          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);
        }
        const Key& key;
        const Value& val;
        const typename _WriteMap::Key& own_key;
        const typename _WriteMap::Value& own_val;
        _WriteMap& m;
        Constraints() {}
      };
    };

    /// Read/writable map concept

    /// Read/writable map concept.
    ///
    template<typename K, typename T>
    class ReadWriteMap : public ReadMap<K,T>,
                         public WriteMap<K,T>
    {
    public:
      /// The key type of the map.
      typedef K Key;
      /// \brief The value type of the map.
      /// (The type of objects associated with the keys).
      typedef T Value;

      /// Returns the value associated with the given key.
      Value operator[](const Key &) const {
        Value *r = 0;
        return *r;
      }

      /// Sets the value associated with the given 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

    /// 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;
      /// The key type of the map.
      typedef K Key;
      /// \brief The value type of the map.
      /// (The type of objects associated with the keys).
      typedef T Value;
      /// The reference type of the map.
      typedef R Reference;
      /// The const reference type of the map.
      typedef CR ConstReference;

    public:

      /// Returns a reference to the value associated with the given key.
      Reference operator[](const Key &) {
        Value *r = 0;
        return *r;
      }

      /// Returns a const reference to the value associated with the given key.
      ConstReference operator[](const Key &) const {
        Value *r = 0;
        return *r;
      }

      /// Sets the value associated with the given key.
      void set(const Key &k,const Value &t) { operator[](k)=t; }

      template<typename _ReferenceMap>
      struct Constraints {
        typename enable_if<typename _ReferenceMap::ReferenceMapTag, void>::type
        constraints() {
          checkConcept<ReadWriteMap<K, T>, _ReferenceMap >();
          ref = m[key];
          m[key] = val;
          m[key] = ref;
          m[key] = cref;
          own_ref = m[own_key];
          m[own_key] = own_val;
          m[own_key] = own_ref;
          m[own_key] = own_cref;
          m[key] = m[own_key];
          m[own_key] = m[key];
        }
        const Key& key;
        Value& val;
        Reference ref;
        ConstReference cref;
        const typename _ReferenceMap::Key& own_key;
        typename _ReferenceMap::Value& own_val;
        typename _ReferenceMap::Reference own_ref;
        typename _ReferenceMap::ConstReference own_cref;
        _ReferenceMap& m;
        Constraints() {}
      };
    };

    // @}

  } //namespace concepts

} //namespace lemon

#endif