RhodeCode

/* -*- C++ -*-

 *

 * This file is a part of LEMON, a generic C++ optimization library

 *

 * Copyright (C) 2003-2007

 * 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.

 *

 */

// This file contains a modified version of the concept checking

// utility from BOOST.

// See the appropriate copyright notice below.

// (C) Copyright Jeremy Siek 2000.

// Distributed under the Boost Software License, Version 1.0. (See

// accompanying file LICENSE_1_0.txt or copy at

// http://www.boost.org/LICENSE_1_0.txt)

//

// Revision History:

//   05 May   2001: Workarounds for HP aCC from Thomas Matelich. (Jeremy Siek)

//   02 April 2001: Removed limits header altogether. (Jeremy Siek)

//   01 April 2001: Modified to use new <boost/limits.hpp> header. (JMaddock)

//

// See http://www.boost.org/libs/concept_check for documentation.

#ifndef LEMON_CONCEPT_CHECKS_H

#define LEMON_CONCEPT_CHECKS_H

namespace lemon {

  /*

    "inline" is used for ignore_unused_variable_warning()

    and function_requires() to make sure there is no

    overtarget with g++.

  */

  template <class T> inline void ignore_unused_variable_warning(const T&) { }

  template <class Concept>

  inline void function_requires()

  {

#if !defined(NDEBUG)

    void (Concept::*x)() = & Concept::constraints;

    ignore_unused_variable_warning(x);

#endif

  }

  template <typename Concept, typename Type>

  inline void checkConcept() {

#if !defined(NDEBUG)

    typedef typename Concept::template Constraints<Type> ConceptCheck;

    void (ConceptCheck::*x)() = & ConceptCheck::constraints;

    ignore_unused_variable_warning(x);

#endif

  }

#define BOOST_CLASS_REQUIRE(type_var, ns, concept) \

  typedef void (ns::concept <type_var>::* func##type_var##concept)(); \

  template <func##type_var##concept Tp1_> \

  struct concept_checking_##type_var##concept { }; \

  typedef concept_checking_##type_var##concept< \

    BOOST_FPTR ns::concept<type_var>::constraints> \

    concept_checking_typedef_##type_var##concept

#define BOOST_CLASS_REQUIRE2(type_var1, type_var2, ns, concept) \

  typedef void (ns::concept <type_var1,type_var2>::* \

     func##type_var1##type_var2##concept)(); \

  template <func##type_var1##type_var2##concept Tp1_> \

  struct concept_checking_##type_var1##type_var2##concept { }; \

  typedef concept_checking_##type_var1##type_var2##concept< \

    BOOST_FPTR ns::concept<type_var1,type_var2>::constraints> \

    concept_checking_typedef_##type_var1##type_var2##concept

#define BOOST_CLASS_REQUIRE3(tv1, tv2, tv3, ns, concept) \

  typedef void (ns::concept <tv1,tv2,tv3>::* \

     func##tv1##tv2##tv3##concept)(); \

  template <func##tv1##tv2##tv3##concept Tp1_> \

  struct concept_checking_##tv1##tv2##tv3##concept { }; \

  typedef concept_checking_##tv1##tv2##tv3##concept< \

    BOOST_FPTR ns::concept<tv1,tv2,tv3>::constraints> \

    concept_checking_typedef_##tv1##tv2##tv3##concept

#define BOOST_CLASS_REQUIRE4(tv1, tv2, tv3, tv4, ns, concept) \

  typedef void (ns::concept <tv1,tv2,tv3,tv4>::* \

     func##tv1##tv2##tv3##tv4##concept)(); \

  template <func##tv1##tv2##tv3##tv4##concept Tp1_> \

  struct concept_checking_##tv1##tv2##tv3##tv4##concept { }; \

  typedef concept_checking_##tv1##tv2##tv3##tv4##concept< \

    BOOST_FPTR ns::concept<tv1,tv2,tv3,tv4>::constraints> \

    concept_checking_typedef_##tv1##tv2##tv3##tv4##concept

} // namespace lemon

#endif // LEMON_CONCEPT_CHECKS_H

/* -*- C++ -*-

 *

 * This file is a part of LEMON, a generic C++ optimization library

 *

 * Copyright (C) 2003-2007

 * 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/bits/utility.h>

#include <lemon/concept_check.h>

///\ingroup concept

///\file

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

namespace lemon {

  namespace concepts {

    /// \addtogroup concept

    /// @{

    /// Readable map 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;

      /// Returns the value associated with a key.

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

      ///

      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

    /// 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

    /// 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

    /// 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 concepts

} //namespace lemon

#endif // LEMON_CONCEPT_MAPS_H

/* -*- C++ -*-

 *

 * This file is a part of LEMON, a generic C++ optimization library

 *

 * Copyright (C) 2003-2007

 * 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_MAPS_H

#define LEMON_MAPS_H

#include <iterator>

#include <functional>

#include <vector>

#include <lemon/bits/utility.h>

// #include <lemon/bits/traits.h>

///\file

///\ingroup maps

///\brief Miscellaneous property maps

///

#include <map>

namespace lemon {

  /// \addtogroup maps

  /// @{

  /// 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)

  /// This map can be used 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 is not required (i.e. it will be sent to 

  /// <tt>/dev/null</tt>).

  template<typename K, typename T>

  class NullMap : public MapBase<K, T> {

  public:

    typedef MapBase<K, T> Parent;

    typedef typename Parent::Key Key;

    typedef typename Parent::Value Value;

    /// Gives back a default constructed element.

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

    /// Absorbs the value.

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

  };

  ///Returns a \c NullMap class

  ///This function just returns a \c NullMap class.

  ///\relates NullMap

  template <typename K, typename V> 

  NullMap<K, V> nullMap() {

    return NullMap<K, V>();

  }

  /// Constant map.

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

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

  template<typename K, typename T>

  class ConstMap : public MapBase<K, T> {

  private:

    T v;

  public:

    typedef MapBase<K, T> Parent;

    typedef typename Parent::Key Key;

    typedef typename Parent::Value Value;

    /// Default constructor

    /// Default constructor.

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

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

    ConstMap() {}

    /// Constructor with specified initial value

    /// Constructor with specified initial value.

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

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

    ///\e

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

    ///\e

    void setAll(const T &t) {

      v = t;

    }    

    template<typename T1>

    struct rebind {

      typedef ConstMap<K, T1> other;

    };

    template<typename T1>

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

  };

  ///Returns a \c ConstMap class

  ///This function just returns a \c ConstMap class.

  ///\relates ConstMap

  template<typename K, typename V> 

  inline ConstMap<K, V> constMap(const V &v) {

    return ConstMap<K, V>(v);

  }

  template<typename T, T v>

  struct Const { };

  /// Constant map with inlined constant value.

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

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

  template<typename K, typename V, V v>

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

  public:

    typedef MapBase<K, V> Parent;

    typedef typename Parent::Key Key;

    typedef typename Parent::Value Value;

    ConstMap() { }

    ///\e

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

    ///\e

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

  };

  ///Returns a \c ConstMap class

  ///This function just returns a \c ConstMap class with inlined value.

  ///\relates ConstMap

  template<typename K, typename V, V v> 

  inline ConstMap<K, Const<V, v> > constMap() {

    return ConstMap<K, Const<V, v> >();

  }

  ///Map based on std::map

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

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

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

  class StdMap {

    template <typename K1, typename T1, typename C1>

    friend class StdMap;

  public:

    typedef True ReferenceMapTag;

    ///\e

    typedef K Key;

    ///\e

    typedef T Value;

    ///\e

    typedef T& Reference;

    ///\e

    typedef const T& ConstReference;

  private:

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

    Value _value;

    Map _map;

  public:

    /// Constructor with specified default value

    StdMap(const T& value = T()) : _value(value) {}

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

    /// specifies a default value.

    template <typename T1, typename Comp1>

    StdMap(const std::map<Key, T1, Comp1> &map, const T& value = T()) 

      : _map(map.begin(), map.end()), _value(value) {}

    /// \brief Constructs a map from an other StdMap.

    template<typename T1, typename Comp1>

    StdMap(const StdMap<Key, T1, Comp1> &c) 

      : _map(c._map.begin(), c._map.end()), _value(c._value) {}

  private:

    StdMap& operator=(const StdMap&);

  public:

    ///\e

    Reference operator[](const Key &k) {

      typename Map::iterator it = _map.lower_bound(k);

      if (it != _map.end() && !_map.key_comp()(k, it->first))

	return it->second;

      else

	return _map.insert(it, std::make_pair(k, _value))->second;

    }

    /// \e 

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

      typename Map::const_iterator it = _map.find(k);

      if (it != _map.end())

	return it->second;

      else

	return _value;

    }

    /// \e 

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

      typename Map::iterator it = _map.lower_bound(k);

      if (it != _map.end() && !_map.key_comp()(k, it->first))

	it->second = t;

      else

	_map.insert(it, std::make_pair(k, t));

    }

    /// \e

    void setAll(const T &t) {

      _value = t;

      _map.clear();

    }    

    template <typename T1, typename C1 = std::less<T1> >

    struct rebind {

      typedef StdMap<Key, T1, C1> other;

    };

  };

  /// \brief Map for storing values for the range \c [0..size-1] range keys

  ///

  /// The current map has the \c [0..size-1] keyset and the values

  /// are stored in a \c std::vector<T>  container. It can be used with

  /// some data structures, for example \c UnionFind, \c BinHeap, when 

  /// the used items are small integer numbers. 

  ///

  /// \todo Revise its name

  template <typename T>

  class IntegerMap {

    template <typename T1>

    friend class IntegerMap;

  public:

    typedef True ReferenceMapTag;

    ///\e

    typedef int Key;

    ///\e

    typedef T Value;

    ///\e

    typedef T& Reference;

    ///\e

    typedef const T& ConstReference;

  private:

    typedef std::vector<T> Vector;

    Vector _vector;

  public:

    /// Constructor with specified default value

    IntegerMap(int size = 0, const T& value = T()) : _vector(size, value) {}

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

    template <typename T1>

    IntegerMap(const std::vector<T1>& vector) 

      : _vector(vector.begin(), vector.end()) {}

    /// \brief Constructs a map from an other IntegerMap.

    template <typename T1>

    IntegerMap(const IntegerMap<T1> &c) 

      : _vector(c._vector.begin(), c._vector.end()) {}

    /// \brief Resize the container

    void resize(int size, const T& value = T()) {

      _vector.resize(size, value);

    }

  private:

    IntegerMap& operator=(const IntegerMap&);

  public:

    ///\e

    Reference operator[](Key k) {

      return _vector[k];

    }

    /// \e 

    ConstReference operator[](Key k) const {

      return _vector[k];

    }

    /// \e 

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

      _vector[k] = t;

    }

  };

  /// @}

  /// \addtogroup map_adaptors

  /// @{

  /// \brief Identity map.

  ///

  /// This map gives back the given key as value without any

  /// modification. 

  template <typename T>

  class IdentityMap : public MapBase<T, T> {

  public:

    typedef MapBase<T, T> Parent;

    typedef typename Parent::Key Key;

    typedef typename Parent::Value Value;

    /// \e

    const T& operator[](const T& t) const {

      return t;

    }

  };

  ///Returns an \c IdentityMap class

  ///This function just returns an \c IdentityMap class.

  ///\relates IdentityMap

  template<typename T>

  inline IdentityMap<T> identityMap() {

    return IdentityMap<T>();

  }

  ///\brief Convert the \c Value of a map to another type using

  ///the default conversion.

  ///

  ///This \c concepts::ReadMap "read only map"

  ///converts the \c Value of a map to type \c T.

  ///Its \c Key is inherited from \c M.

  template <typename M, typename T> 

  class ConvertMap : public MapBase<typename M::Key, T> {

    const M& m;

  public:

    typedef MapBase<typename M::Key, T> Parent;

    typedef typename Parent::Key Key;

    typedef typename Parent::Value Value;

    ///Constructor

    ///Constructor.

    ///\param _m is the underlying map.

    ConvertMap(const M &_m) : m(_m) {};

    /// \brief The subscript operator.

    ///

    /// The subscript operator.

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

  };

  ///Returns a \c ConvertMap class

  ///This function just returns a \c ConvertMap class.

  ///\relates ConvertMap

  template<typename T, typename M>

  inline ConvertMap<M, T> convertMap(const M &m) {

    return ConvertMap<M, T>(m);

  }

  ///Simple wrapping of a map

  ///This \c concepts::ReadMap "read only map" returns the simple

  ///wrapping of the given map. Sometimes the reference maps cannot be

  ///combined with simple read maps. This map adaptor wraps the given

  ///map to simple read map.

  ///

  ///\sa SimpleWriteMap

  ///

  /// \todo Revise the misleading name 

  template<typename M> 

  class SimpleMap : public MapBase<typename M::Key, typename M::Value> {

    const M& m;

  public:

    typedef MapBase<typename M::Key, typename M::Value> Parent;

    typedef typename Parent::Key Key;

    typedef typename Parent::Value Value;

    ///Constructor

    SimpleMap(const M &_m) : m(_m) {};

    ///\e

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

  };

  ///Simple writable wrapping of the map

  ///This \c concepts::WriteMap "write map" returns the simple

  ///wrapping of the given map. Sometimes the reference maps cannot be

  ///combined with simple read-write maps. This map adaptor wraps the

  ///given map to simple read-write map.

  ///

  ///\sa SimpleMap

  ///

  /// \todo Revise the misleading name

  template<typename M> 

  class SimpleWriteMap : public MapBase<typename M::Key, typename M::Value> {

    M& m;

  public:

    typedef MapBase<typename M::Key, typename M::Value> Parent;

    typedef typename Parent::Key Key;

    typedef typename Parent::Value Value;

    ///Constructor

    SimpleWriteMap(M &_m) : m(_m) {};

    ///\e

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

    ///\e

    void set(Key k, const Value& c) { m.set(k, c); }

  };

  ///Sum of two maps

  ///This \c concepts::ReadMap "read only map" returns the sum of the two

  ///given maps.

  ///Its \c Key and \c Value are inherited from \c M1.

  ///The \c Key and \c Value of M2 must be convertible to those of \c M1.

  template<typename M1, typename M2> 

  class AddMap : public MapBase<typename M1::Key, typename M1::Value> {

    const M1& m1;

    const M2& m2;

  public:

    typedef MapBase<typename M1::Key, typename M1::Value> Parent;

    typedef typename Parent::Key Key;

    typedef typename Parent::Value Value;

    ///Constructor

    AddMap(const M1 &_m1,const M2 &_m2) : m1(_m1), m2(_m2) {};

    ///\e

    Value operator[](Key k) const {return m1[k]+m2[k];}

  };

  ///Returns an \c AddMap class

  ///This function just returns an \c AddMap class.

  ///\todo How to call these type of functions?

  ///

  ///\relates AddMap

  template<typename M1, typename M2> 

  inline AddMap<M1, M2> addMap(const M1 &m1,const M2 &m2) {

    return AddMap<M1, M2>(m1,m2);

  }

  ///Shift a map with a constant.

  ///This \c concepts::ReadMap "read only map" returns the sum of the

  ///given map and a constant value.

  ///Its \c Key and \c Value are inherited from \c M.

  ///

  ///Actually,

  ///\code

  ///  ShiftMap<X> sh(x,v);

  ///\endcode

  ///is equivalent to

  ///\code

  ///  ConstMap<X::Key, X::Value> c_tmp(v);

  ///  AddMap<X, ConstMap<X::Key, X::Value> > sh(x,v);

  ///\endcode

  ///

  ///\sa ShiftWriteMap

  template<typename M, typename C = typename M::Value> 

  class ShiftMap : public MapBase<typename M::Key, typename M::Value> {

    const M& m;

    C v;

  public:

    typedef MapBase<typename M::Key, typename M::Value> Parent;

    typedef typename Parent::Key Key;

    typedef typename Parent::Value Value;

    ///Constructor

    ///Constructor.

    ///\param _m is the undelying map.

    ///\param _v is the shift value.

    ShiftMap(const M &_m, const C &_v ) : m(_m), v(_v) {};

    ///\e

    Value operator[](Key k) const {return m[k] + v;}

  };

  ///Shift a map with a constant (ReadWrite version).

  ///This \c concepts::ReadWriteMap "read-write map" returns the sum of the

  ///given map and a constant value. It makes also possible to write the map.

  ///Its \c Key and \c Value are inherited from \c M.

  ///

  ///\sa ShiftMap

  template<typename M, typename C = typename M::Value> 

  class ShiftWriteMap : public MapBase<typename M::Key, typename M::Value> {

    M& m;

    C v;

  public:

    typedef MapBase<typename M::Key, typename M::Value> Parent;

    typedef typename Parent::Key Key;

    typedef typename Parent::Value Value;

    ///Constructor

    ///Constructor.

    ///\param _m is the undelying map.

    ///\param _v is the shift value.

    ShiftWriteMap(M &_m, const C &_v ) : m(_m), v(_v) {};

    /// \e

    Value operator[](Key k) const {return m[k] + v;}

    /// \e

    void set(Key k, const Value& c) { m.set(k, c - v); }

  };

  ///Returns a \c ShiftMap class

  ///This function just returns a \c ShiftMap class.

  ///\relates ShiftMap

  template<typename M, typename C> 

  inline ShiftMap<M, C> shiftMap(const M &m,const C &v) {

    return ShiftMap<M, C>(m,v);

  }

  ///Returns a \c ShiftWriteMap class

  ///This function just returns a \c ShiftWriteMap class.

  ///\relates ShiftWriteMap

  template<typename M, typename C> 

  inline ShiftWriteMap<M, C> shiftMap(M &m,const C &v) {

    return ShiftWriteMap<M, C>(m,v);

  }

  ///Difference of two maps

  ///This \c concepts::ReadMap "read only map" returns the difference

  ///of the values of the two given maps.

  ///Its \c Key and \c Value are inherited from \c M1.

  ///The \c Key and \c Value of \c M2 must be convertible to those of \c M1.

  ///

  /// \todo Revise the misleading name

  template<typename M1, typename M2> 

  class SubMap : public MapBase<typename M1::Key, typename M1::Value> {

    const M1& m1;

    const M2& m2;

  public:

    typedef MapBase<typename M1::Key, typename M1::Value> Parent;

    typedef typename Parent::Key Key;

    typedef typename Parent::Value Value;

    ///Constructor

    SubMap(const M1 &_m1,const M2 &_m2) : m1(_m1), m2(_m2) {};

    /// \e

    Value operator[](Key k) const {return m1[k]-m2[k];}

  };

  ///Returns a \c SubMap class

  ///This function just returns a \c SubMap class.

  ///

  ///\relates SubMap

  template<typename M1, typename M2> 

  inline SubMap<M1, M2> subMap(const M1 &m1, const M2 &m2) {

    return SubMap<M1, M2>(m1, m2);

  }

  ///Product of two maps

  ///This \c concepts::ReadMap "read only map" returns the product of the

  ///values of the two given maps.

  ///Its \c Key and \c Value are inherited from \c M1.

  ///The \c Key and \c Value of \c M2 must be convertible to those of \c M1.

  template<typename M1, typename M2> 

  class MulMap : public MapBase<typename M1::Key, typename M1::Value> {

    const M1& m1;

    const M2& m2;

  public:

    typedef MapBase<typename M1::Key, typename M1::Value> Parent;

    typedef typename Parent::Key Key;

    typedef typename Parent::Value Value;

    ///Constructor

    MulMap(const M1 &_m1,const M2 &_m2) : m1(_m1), m2(_m2) {};

    /// \e

    Value operator[](Key k) const {return m1[k]*m2[k];}

  };

  ///Returns a \c MulMap class

  ///This function just returns a \c MulMap class.

  ///\relates MulMap

  template<typename M1, typename M2> 

  inline MulMap<M1, M2> mulMap(const M1 &m1,const M2 &m2) {

    return MulMap<M1, M2>(m1,m2);

  }

  ///Scales a map with a constant.

  ///This \c concepts::ReadMap "read only map" returns the value of the

  ///given map multiplied from the left side with a constant value.

  ///Its \c Key and \c Value are inherited from \c M.

  ///

  ///Actually,

  ///\code

  ///  ScaleMap<X> sc(x,v);

  ///\endcode

  ///is equivalent to

  ///\code

  ///  ConstMap<X::Key, X::Value> c_tmp(v);

  ///  MulMap<X, ConstMap<X::Key, X::Value> > sc(x,v);

  ///\endcode

  ///

  ///\sa ScaleWriteMap

  template<typename M, typename C = typename M::Value> 

  class ScaleMap : public MapBase<typename M::Key, typename M::Value> {

    const M& m;

    C v;

  public:

    typedef MapBase<typename M::Key, typename M::Value> Parent;

    typedef typename Parent::Key Key;

    typedef typename Parent::Value Value;

    ///Constructor

    ///Constructor.

    ///\param _m is the undelying map.

    ///\param _v is the scaling value.

    ScaleMap(const M &_m, const C &_v ) : m(_m), v(_v) {};

    /// \e

    Value operator[](Key k) const {return v * m[k];}

  };

  ///Scales a map with a constant (ReadWrite version).

  ///This \c concepts::ReadWriteMap "read-write map" returns the value of the

  ///given map multiplied from the left side with a constant value. It can

  ///also be used as write map if the \c / operator is defined between

  ///\c Value and \c C and the given multiplier is not zero.

  ///Its \c Key and \c Value are inherited from \c M.

  ///

  ///\sa ScaleMap

  template<typename M, typename C = typename M::Value> 

  class ScaleWriteMap : public MapBase<typename M::Key, typename M::Value> {

    M& m;

    C v;

  public:

    typedef MapBase<typename M::Key, typename M::Value> Parent;

    typedef typename Parent::Key Key;

    typedef typename Parent::Value Value;

    ///Constructor

    ///Constructor.

    ///\param _m is the undelying map.

    ///\param _v is the scaling value.

    ScaleWriteMap(M &_m, const C &_v ) : m(_m), v(_v) {};

    /// \e

    Value operator[](Key k) const {return v * m[k];}

    /// \e

    void set(Key k, const Value& c) { m.set(k, c / v);}

  };

  ///Returns a \c ScaleMap class

  ///This function just returns a \c ScaleMap class.

  ///\relates ScaleMap

  template<typename M, typename C> 

  inline ScaleMap<M, C> scaleMap(const M &m,const C &v) {

    return ScaleMap<M, C>(m,v);

  }

  ///Returns a \c ScaleWriteMap class

  ///This function just returns a \c ScaleWriteMap class.

  ///\relates ScaleWriteMap

  template<typename M, typename C> 

  inline ScaleWriteMap<M, C> scaleMap(M &m,const C &v) {

    return ScaleWriteMap<M, C>(m,v);

  }

  ///Quotient of two maps

  ///This \c concepts::ReadMap "read only map" returns the quotient of the

  ///values of the two given maps.

  ///Its \c Key and \c Value are inherited from \c M1.

  ///The \c Key and \c Value of \c M2 must be convertible to those of \c M1.

  template<typename M1, typename M2> 

  class DivMap : public MapBase<typename M1::Key, typename M1::Value> {

    const M1& m1;

    const M2& m2;

  public:

    typedef MapBase<typename M1::Key, typename M1::Value> Parent;

    typedef typename Parent::Key Key;

    typedef typename Parent::Value Value;

    ///Constructor

    DivMap(const M1 &_m1,const M2 &_m2) : m1(_m1), m2(_m2) {};

    /// \e

    Value operator[](Key k) const {return m1[k]/m2[k];}

  };

  ///Returns a \c DivMap class

  ///This function just returns a \c DivMap class.

  ///\relates DivMap

  template<typename M1, typename M2> 

  inline DivMap<M1, M2> divMap(const M1 &m1,const M2 &m2) {

    return DivMap<M1, M2>(m1,m2);

  }

  ///Composition of two maps

  ///This \c concepts::ReadMap "read only map" returns the composition of

  ///two given maps.

  ///That is to say, if \c m1 is of type \c M1 and \c m2 is of \c M2,

  ///then for

  ///\code

  ///  ComposeMap<M1, M2> cm(m1,m2);

  ///\endcode

  /// <tt>cm[x]</tt> will be equal to <tt>m1[m2[x]]</tt>.

  ///

  ///Its \c Key is inherited from \c M2 and its \c Value is from \c M1.

  ///\c M2::Value must be convertible to \c M1::Key.

  ///

  ///\sa CombineMap

  ///

  ///\todo Check the requirements.

  template <typename M1, typename M2> 

  class ComposeMap : public MapBase<typename M2::Key, typename M1::Value> {

    const M1& m1;

    const M2& m2;

  public:

    typedef MapBase<typename M2::Key, typename M1::Value> Parent;

    typedef typename Parent::Key Key;

    typedef typename Parent::Value Value;

    ///Constructor

    ComposeMap(const M1 &_m1,const M2 &_m2) : m1(_m1), m2(_m2) {};

    /// \e

    /// \todo Use the  MapTraits once it is ported.

    ///

    //typename MapTraits<M1>::ConstReturnValue

    typename M1::Value

    operator[](Key k) const {return m1[m2[k]];}

  };

  ///Returns a \c ComposeMap class

  ///This function just returns a \c ComposeMap class.

  ///\relates ComposeMap

  template <typename M1, typename M2> 

  inline ComposeMap<M1, M2> composeMap(const M1 &m1,const M2 &m2) {

    return ComposeMap<M1, M2>(m1,m2);

  }

  ///Combine of two maps using an STL (binary) functor.

  ///Combine of two maps using an STL (binary) functor.

  ///

  ///This \c concepts::ReadMap "read only map" takes two maps and a

  ///binary functor and returns the composition of the two

  ///given maps unsing the functor. 

  ///That is to say, if \c m1 and \c m2 is of type \c M1 and \c M2

  ///and \c f is of \c F, then for

  ///\code

  ///  CombineMap<M1,M2,F,V> cm(m1,m2,f);

  ///\endcode