hegyi@815: #define SKELETON
hegyi@815: // -*- c++ -*- //
hegyi@815: 
hegyi@815: ///\ingroup skeletons
hegyi@815: ///\file
hegyi@815: ///\brief Classes for representing paths in graphs.
hegyi@815: 
alpar@921: #ifndef LEMON_PATH_H
alpar@921: #define LEMON_PATH_H
hegyi@815: 
alpar@921: #include <lemon/invalid.h>
hegyi@815: 
alpar@921: namespace lemon {
hegyi@815:   namespace skeleton {
hegyi@815:     /// \addtogroup skeletons
hegyi@815:     /// @{
hegyi@815:     
hegyi@815:     
hegyi@815:     //! \brief A skeletom structure for representing directed paths in a graph.
hegyi@815:     //!
hegyi@815:     //! A skeleton structure for representing directed paths in a graph.
hegyi@815:     //! \param GR The graph type in which the path is.
hegyi@815:     //! 
hegyi@815:     //! In a sense, the path can be treated as a graph, for is has \c NodeIt
hegyi@815:     //! and \c EdgeIt with the same usage. These types converts to the \c Node
hegyi@815:     //! and \c Edge of the original graph.
hegyi@815:     template<typename GR>
hegyi@815:     class Path {
hegyi@815:     public:
hegyi@815:       
hegyi@815:       /// Type of the underlying graph.
hegyi@815:       typedef /*typename*/ GR Graph;
hegyi@815:       /// Edge type of the underlying graph.
hegyi@815:       typedef typename Graph::Edge GraphEdge; 
hegyi@815:       /// Node type of the underlying graph.
hegyi@815:      typedef typename Graph::Node GraphNode;
hegyi@815:       class NodeIt;
hegyi@815:       class EdgeIt;
hegyi@815:       
hegyi@815:       /// \param _G The graph in which the path is.
hegyi@815:       ///
hegyi@815:       Path(const Graph &_G) {}
hegyi@815:       
hegyi@815:       /// Length of the path.
hegyi@815:       size_t length() const {}
hegyi@815:       /// Returns whether the path is empty.
hegyi@815:       bool empty() const {}
hegyi@815:       
hegyi@815:       /// Resets the path to an empty path.
hegyi@815:       void clear() {}
hegyi@815: 
hegyi@815:       /// \brief Starting point of the path.
hegyi@815:       ///
hegyi@815:       /// Starting point of the path.
hegyi@815:       /// Returns INVALID if the path is empty.
hegyi@815:       GraphNode head() const {}
hegyi@815:       /// \brief End point of the path.
hegyi@815:       ///
hegyi@815:       /// End point of the path.
hegyi@815:       /// Returns INVALID if the path is empty.
hegyi@815:       GraphNode tail() const {}
hegyi@815: 
hegyi@815:       /// \brief First NodeIt/EdgeIt.
hegyi@815:       ///
hegyi@815:       /// Initializes node or edge iterator to point to the first
hegyi@815:       /// node or edge.
hegyi@815:       template<typename It>
hegyi@815:       It& first(It &i) const { return i=It(*this); }
hegyi@815: 
hegyi@815:       /// \brief The head of an edge.
hegyi@815:       ///
hegyi@815:       /// Returns node iterator pointing to the head node of the
hegyi@815:       /// given edge iterator.
hegyi@815:       NodeIt head(const EdgeIt& e) const {}
hegyi@815: 
hegyi@815:       /// \brief The tail of an edge.
hegyi@815:       ///
hegyi@815:       /// Returns node iterator pointing to the tail node of the
hegyi@815:       /// given edge iterator.
hegyi@815:       NodeIt tail(const EdgeIt& e) const {}
hegyi@815: 
hegyi@815: 
hegyi@815:       /* Iterator classes */
hegyi@815: 
hegyi@815:       /**
hegyi@815:        * \brief Iterator class to iterate on the edges of the paths
hegyi@815:        * 
hegyi@815:        * \ingroup skeletons
hegyi@815:        * This class is used to iterate on the edges of the paths
hegyi@815:        *
hegyi@815:        * Of course it converts to Graph::Edge
hegyi@815:        * 
hegyi@815:        */
hegyi@815:       class EdgeIt {
hegyi@815:       public:
hegyi@815: 	/// Default constructor
hegyi@815: 	EdgeIt() {}
hegyi@815: 	/// Invalid constructor
hegyi@815: 	EdgeIt(Invalid) {}
hegyi@815: 	/// Constructor with starting point
hegyi@815: 	EdgeIt(const Path &_p) {}
hegyi@815: 
hegyi@815: 	operator GraphEdge () const {}
hegyi@815: 
hegyi@815: 	/// Next edge
hegyi@815: 	EdgeIt& operator++() {}
hegyi@815: 
hegyi@815: 	/// Comparison operator
hegyi@815: 	bool operator==(const EdgeIt& e) const {}
hegyi@815: 	/// Comparison operator
hegyi@815: 	bool operator!=(const EdgeIt& e) const {}
hegyi@815: // 	/// Comparison operator
hegyi@815: //      /// \todo It is not clear what is the "natural" ordering.
hegyi@815: // 	bool operator<(const EdgeIt& e) const {}
hegyi@815: 
hegyi@815:       };
hegyi@815: 
hegyi@815:       /**
hegyi@815:        * \brief Iterator class to iterate on the nodes of the paths
hegyi@815:        * 
hegyi@815:        * \ingroup skeletons
hegyi@815:        * This class is used to iterate on the nodes of the paths
hegyi@815:        *
hegyi@815:        * Of course it converts to Graph::Node.
hegyi@815:        * 
hegyi@815:        */
hegyi@815:       class NodeIt {
hegyi@815:       public:
hegyi@815: 	/// Default constructor
hegyi@815: 	NodeIt() {}
hegyi@815: 	/// Invalid constructor
hegyi@815: 	NodeIt(Invalid) {}
hegyi@815: 	/// Constructor with starting point
hegyi@815: 	NodeIt(const Path &_p) {}
hegyi@815: 
hegyi@815: 	///Conversion to Graph::Node
hegyi@815: 	operator const GraphNode& () const {}
hegyi@815: 	/// Next node
hegyi@815: 	NodeIt& operator++() {}
hegyi@815: 
hegyi@815: 	/// Comparison operator
hegyi@815: 	bool operator==(const NodeIt& e) const {}
hegyi@815: 	/// Comparison operator
hegyi@815: 	bool operator!=(const NodeIt& e) const {}
hegyi@815: // 	/// Comparison operator
hegyi@815: //      /// \todo It is not clear what is the "natural" ordering.
hegyi@815: // 	bool operator<(const NodeIt& e) const {}
hegyi@815: 
hegyi@815:       };
hegyi@815: 
hegyi@815:       friend class Builder;    
hegyi@815: 
hegyi@815:       /**
hegyi@815:        * \brief Class to build paths
hegyi@815:        * 
hegyi@815:        * \ingroup skeletons
hegyi@815:        * This class is used to fill a path with edges.
hegyi@815:        *
hegyi@815:        * You can push new edges to the front and to the back of the path in
hegyi@815:        * arbitrary order then you should commit these changes to the graph.
hegyi@815:        *
hegyi@815:        * While the builder is active (after the first modifying
hegyi@815:        * operation and until the call of \ref commit())
hegyi@815:        * the underlining Path is in a
hegyi@815:        * "transitional" state (operations on it have undefined result).
hegyi@815:        */
hegyi@815:       class Builder {
hegyi@815:       public:
hegyi@815: 
hegyi@815:         Path &P;
hegyi@815: 
hegyi@815: 	///\param _P the path you want to fill in.
hegyi@815: 	///
hegyi@815: 	Builder(Path &_P) : P(_P) {}
hegyi@815: 
hegyi@815: 	/// Sets the starting node of the path.
hegyi@815:       
hegyi@815: 	/// Sets the starting node of the path. Edge added to the path
hegyi@815: 	/// afterwards have to be incident to this node.
hegyi@815: 	/// You \em must start building an empry path with this functions.
hegyi@815: 	/// (And you \em must \em not use it later).
hegyi@815: 	/// \sa pushFront()
hegyi@815: 	/// \sa pushBack()
hegyi@815: 	void setStartNode(const GraphNode &) {}
hegyi@815: 
hegyi@815: 	///Push a new edge to the front of the path
hegyi@815: 
hegyi@815: 	///Push a new edge to the front of the path.
hegyi@815: 	///If the path is empty, you \em must call \ref setStartNode() before
hegyi@815: 	///the first use of \ref pushFront().
hegyi@815: 	void pushFront(const GraphEdge& e) {}
hegyi@815: 
hegyi@815: 	///Push a new edge to the back of the path
hegyi@815: 
hegyi@815: 	///Push a new edge to the back of the path.
hegyi@815: 	///If the path is empty, you \em must call \ref setStartNode() before
hegyi@815: 	///the first use of \ref pushBack().
hegyi@815: 	void pushBack(const GraphEdge& e) {}
hegyi@815: 
hegyi@815: 	///Commit the changes to the path.
hegyi@815: 	void commit() {}
hegyi@815: 
hegyi@815: 	///Reserve (front) storage for the builder in advance.
hegyi@815: 
hegyi@815: 	///If you know an reasonable upper bound of the number of the edges
hegyi@815: 	///to add to the front of the path,
hegyi@815: 	///using this function you may speed up the building.
hegyi@815: 	void reserveFront(size_t r) {}
hegyi@815: 	///Reserve (back) storage for the builder in advance.
hegyi@815: 
hegyi@815: 	///If you know an reasonable upper bound of the number of the edges
hegyi@815: 	///to add to the back of the path,
hegyi@815: 	///using this function you may speed up the building.
hegyi@815: 	void reserveBack(size_t r) {}
hegyi@815:       };
hegyi@815:     };
hegyi@815: 
hegyi@815:   ///@}
hegyi@815:   }
hegyi@815:   
alpar@921: } // namespace lemon
hegyi@815: 
alpar@921: #endif // LEMON_PATH_H