RhodeCode

      /// \brief Gives back an item by its id.

      ///

      /// Gives back an item by its id.

      Item operator[](int id) const { return _graph->fromId(id, Item());}

    private:

      const Graph* _graph;

    };

    /// \brief Gives back the inverse of the map.

    ///

    /// Gives back the inverse of the IdMap.

    InverseMap inverse() const { return InverseMap(*_graph);}

  };

  /// \brief General cross reference graph map type.

  /// This class provides simple invertable graph maps.

  /// It wraps a standard graph map (\c NodeMap, \c ArcMap or \c EdgeMap)

  /// and if a key is set to a new value, then stores it in the inverse map.

  /// The graph items can be accessed by their values either using

  /// \c InverseMap or \c operator()(), and the values of the map can be

  /// accessed with an STL compatible forward iterator (\c ValueIt).

  /// 

  /// This map is intended to be used when all associated values are

  /// different (the map is actually invertable) or there are only a few

  /// items with the same value.

  /// Otherwise consider to use \c IterableValueMap, which is more 

  /// suitable and more efficient for such cases. It provides iterators

  /// to traverse the items with the same associated value, however

      unsigned int size() const {

        return _inverted.size();

      }

    private:

      const RangeIdMap& _inverted;

    };

    /// \brief Gives back the inverse of the map.

    ///

    /// Gives back the inverse of the RangeIdMap.

    const InverseMap inverse() const {

      return InverseMap(*this);

    }

  };

  /// \brief Dynamic iterable \c bool map.

  ///

  /// This class provides a special graph map type which can store a

  /// \c bool value for graph items (\c Node, \c Arc or \c Edge).

  /// For both \c true and \c false values it is possible to iterate on

  /// the keys mapped to the value.

  ///

  /// This type is a reference map, so it can be modified with the

  /// subscript operator.

  ///

  /// \tparam GR The graph type.

  /// \tparam K The key type of the map (\c GR::Node, \c GR::Arc or

  /// \c GR::Edge).

  ///

  /// \see IterableIntMap, IterableValueMap

  /// \see CrossRefMap