RhodeCode

  /// it could be the base of a real visitor class.

  template <typename _Digraph>

  struct BfsVisitor {

    typedef _Digraph Digraph;

    typedef typename Digraph::Arc Arc;

    typedef typename Digraph::Node Node;

    /// \brief Called for the source node(s) of the BFS.

    ///

    /// This function is called for the source node(s) of the BFS.

    void start(const Node& node) {}

    /// \brief Called when a node is reached first time.

    ///

    /// This function is called when a node is reached first time.

    void reach(const Node& node) {}

    /// \brief Called when a node is processed.

    ///

    /// This function is called when a node is processed.

    void process(const Node& node) {}

    /// \brief Called when an arc reaches a new node.

    ///

    /// This function is called when the BFS finds an arc whose target node

    /// is not reached yet.

    void discover(const Arc& arc) {}

    /// \brief Called when an arc is examined but its target node is

    /// already discovered.

    ///

    /// This function is called when an arc is examined but its target node is

    /// already discovered.

    void examine(const Arc& arc) {}

  };

#else

  template <typename _Digraph>

  struct BfsVisitor {

    typedef _Digraph Digraph;

    typedef typename Digraph::Arc Arc;

    typedef typename Digraph::Node Node;

    void start(const Node&) {}

    void reach(const Node&) {}

    void process(const Node&) {}

    void discover(const Arc&) {}

    void examine(const Arc&) {}

    template <typename _Visitor>

    struct Constraints {

      void constraints() {

        Arc arc;

        Node node;

        visitor.start(node);

        visitor.reach(node);

        visitor.process(node);

        visitor.discover(arc);

        visitor.examine(arc);

      }

      _Visitor& visitor;

    };

  };

#endif

  /// \brief Default traits class of BfsVisit class.

  ///

  /// Default traits class of BfsVisit class.

  /// \tparam _Digraph The type of the digraph the algorithm runs on.

  template<class _Digraph>

  struct BfsVisitDefaultTraits {

    /// \brief The type of the digraph the algorithm runs on.

    typedef _Digraph Digraph;

    /// \brief The type of the map that indicates which nodes are reached.

    ///

    /// The type of the map that indicates which nodes are reached.

    /// It must meet the \ref concepts::ReadWriteMap "ReadWriteMap" concept.

    typedef typename Digraph::template NodeMap<bool> ReachedMap;

    /// \brief Instantiates a \ref ReachedMap.

    ///

    /// This function instantiates a \ref ReachedMap.

    /// \param digraph is the digraph, to which

    /// we would like to define the \ref ReachedMap.

    static ReachedMap *createReachedMap(const Digraph &digraph) {

      return new ReachedMap(digraph);

    }

  };

  /// \ingroup search

  ///

  /// \brief %BFS algorithm class with visitor interface.

  ///

  /// This class provides an efficient implementation of the %BFS algorithm

  /// with visitor interface.

  ///

  /// The %BfsVisit class provides an alternative interface to the Bfs

  /// class. It works with callback mechanism, the BfsVisit object calls

  /// the member functions of the \c Visitor class on every BFS event.

  ///

  /// \tparam _Digraph The type of the digraph the algorithm runs on.

  /// The default value is

  /// \ref ListDigraph. The value of _Digraph is not used directly by

  /// \ref BfsVisit, it is only passed to \ref BfsVisitDefaultTraits.

  /// \tparam _Visitor The Visitor type that is used by the algorithm.

  /// \ref BfsVisitor "BfsVisitor<_Digraph>" is an empty visitor, which

  /// does not observe the BFS events. If you want to observe the BFS

  /// events, you should implement your own visitor class.

  /// \tparam _Traits Traits class to set various data types used by the

  /// algorithm. The default traits class is

  /// \ref BfsVisitDefaultTraits "BfsVisitDefaultTraits<_Digraph>".

  /// See \ref BfsVisitDefaultTraits for the documentation of

  /// a BFS visit traits class.

#ifdef DOXYGEN

  template <typename _Digraph, typename _Visitor, typename _Traits>

#else

  template <typename _Digraph = ListDigraph,

            typename _Visitor = BfsVisitor<_Digraph>,

            typename _Traits = BfsDefaultTraits<_Digraph> >

#endif

  class BfsVisit {

  public:

    /// \brief \ref Exception for uninitialized parameters.

    ///

    /// This error represents problems in the initialization

    /// of the parameters of the algorithm.

    class UninitializedParameter : public lemon::UninitializedParameter {

    public:

      virtual const char* what() const throw()

      {

        return "lemon::BfsVisit::UninitializedParameter";

      }

    };

    ///The traits class.

    typedef _Traits Traits;

    ///The type of the digraph the algorithm runs on.

    typedef typename Traits::Digraph Digraph;

    ///The visitor type used by the algorithm.

    typedef _Visitor Visitor;

    ///The type of the map that indicates which nodes are reached.

    typedef typename Traits::ReachedMap ReachedMap;

  private:

    typedef typename Digraph::Node Node;

    typedef typename Digraph::NodeIt NodeIt;

    typedef typename Digraph::Arc Arc;

    typedef typename Digraph::OutArcIt OutArcIt;

    //Pointer to the underlying digraph.

    const Digraph *_digraph;

    //Pointer to the visitor object.

    Visitor *_visitor;

    //Pointer to the map of reached status of the nodes.

    ReachedMap *_reached;

    //Indicates if _reached is locally allocated (true) or not.

    bool local_reached;

    std::vector<typename Digraph::Node> _list;

    int _list_front, _list_back;

    ///Creates the maps if necessary.

    ///\todo Better memory allocation (instead of new).

    void create_maps() {

      if(!_reached) {

        local_reached = true;

        _reached = Traits::createReachedMap(*_digraph);

      }

    }

  protected:

    BfsVisit() {}

  public:

    typedef BfsVisit Create;

    /// \name Named template parameters

    ///@{

    template <class T>

    struct DefReachedMapTraits : public Traits {

      typedef T ReachedMap;

      static ReachedMap *createReachedMap(const Digraph &digraph) {

        throw UninitializedParameter();

      }

    };

    /// \brief \ref named-templ-param "Named parameter" for setting

    /// ReachedMap type.

    ///

    /// This function is called when the source node is leaved.

    void stop(const Node& node) {}

    /// \brief Called when a node is reached first time.

    ///

    /// This function is called when a node is reached first time.

    void reach(const Node& node) {}

    /// \brief Called when an arc reaches a new node.

    ///

    /// This function is called when the DFS finds an arc whose target node

    /// is not reached yet.

    void discover(const Arc& arc) {}

    /// \brief Called when an arc is examined but its target node is

    /// already discovered.

    ///

    /// This function is called when an arc is examined but its target node is

    /// already discovered.

    void examine(const Arc& arc) {}

    /// \brief Called when the DFS steps back from a node.

    ///

    /// This function is called when the DFS steps back from a node.

    void leave(const Node& node) {}

    /// \brief Called when the DFS steps back on an arc.

    ///

    /// This function is called when the DFS steps back on an arc.

    void backtrack(const Arc& arc) {}

  };

#else

  template <typename _Digraph>

  struct DfsVisitor {

    typedef _Digraph Digraph;

    typedef typename Digraph::Arc Arc;

    typedef typename Digraph::Node Node;

    void start(const Node&) {}

    void stop(const Node&) {}

    void reach(const Node&) {}

    void discover(const Arc&) {}

    void examine(const Arc&) {}

    void leave(const Node&) {}

    void backtrack(const Arc&) {}

    template <typename _Visitor>

    struct Constraints {

      void constraints() {

        Arc arc;

        Node node;

        visitor.start(node);

        visitor.stop(arc);

        visitor.reach(node);

        visitor.discover(arc);

        visitor.examine(arc);

        visitor.leave(node);

        visitor.backtrack(arc);

      }

      _Visitor& visitor;

    };

  };

#endif

  /// \brief Default traits class of DfsVisit class.

  ///

  /// Default traits class of DfsVisit class.

  /// \tparam _Digraph The type of the digraph the algorithm runs on.

  template<class _Digraph>

  struct DfsVisitDefaultTraits {

    /// \brief The type of the digraph the algorithm runs on.

    typedef _Digraph Digraph;

    /// \brief The type of the map that indicates which nodes are reached.

    ///

    /// The type of the map that indicates which nodes are reached.

    /// It must meet the \ref concepts::ReadWriteMap "ReadWriteMap" concept.

    typedef typename Digraph::template NodeMap<bool> ReachedMap;

    /// \brief Instantiates a \ref ReachedMap.

    ///

    /// This function instantiates a \ref ReachedMap.

    /// \param digraph is the digraph, to which

    /// we would like to define the \ref ReachedMap.

    static ReachedMap *createReachedMap(const Digraph &digraph) {

      return new ReachedMap(digraph);

    }

  };

  /// \ingroup search

  ///

  /// \brief %DFS algorithm class with visitor interface.

  ///

  /// This class provides an efficient implementation of the %DFS algorithm

  /// with visitor interface.

  ///

  /// The %DfsVisit class provides an alternative interface to the Dfs

  /// class. It works with callback mechanism, the DfsVisit object calls

  /// the member functions of the \c Visitor class on every DFS event.

  ///

  /// \tparam _Digraph The type of the digraph the algorithm runs on.

  /// The default value is

  /// \ref ListDigraph. The value of _Digraph is not used directly by

  /// \ref DfsVisit, it is only passed to \ref DfsVisitDefaultTraits.

  /// \tparam _Visitor The Visitor type that is used by the algorithm.

  /// \ref DfsVisitor "DfsVisitor<_Digraph>" is an empty visitor, which

  /// does not observe the DFS events. If you want to observe the DFS

  /// events, you should implement your own visitor class.

  /// \tparam _Traits Traits class to set various data types used by the

  /// algorithm. The default traits class is

  /// \ref DfsVisitDefaultTraits "DfsVisitDefaultTraits<_Digraph>".

  /// See \ref DfsVisitDefaultTraits for the documentation of

  /// a DFS visit traits class.

#ifdef DOXYGEN

  template <typename _Digraph, typename _Visitor, typename _Traits>

#else

  template <typename _Digraph = ListDigraph,

            typename _Visitor = DfsVisitor<_Digraph>,

            typename _Traits = DfsDefaultTraits<_Digraph> >

#endif

  class DfsVisit {

  public:

    /// \brief \ref Exception for uninitialized parameters.

    ///

    /// This error represents problems in the initialization

    /// of the parameters of the algorithm.

    class UninitializedParameter : public lemon::UninitializedParameter {

    public:

      virtual const char* what() const throw()

      {

        return "lemon::DfsVisit::UninitializedParameter";

      }

    };

    ///The traits class.

    typedef _Traits Traits;

    ///The type of the digraph the algorithm runs on.

    typedef typename Traits::Digraph Digraph;

    ///The visitor type used by the algorithm.

    typedef _Visitor Visitor;

    ///The type of the map that indicates which nodes are reached.

    typedef typename Traits::ReachedMap ReachedMap;

  private:

    typedef typename Digraph::Node Node;

    typedef typename Digraph::NodeIt NodeIt;

    typedef typename Digraph::Arc Arc;

    typedef typename Digraph::OutArcIt OutArcIt;

    //Pointer to the underlying digraph.

    const Digraph *_digraph;

    //Pointer to the visitor object.

    Visitor *_visitor;

    //Pointer to the map of reached status of the nodes.

    ReachedMap *_reached;

    //Indicates if _reached is locally allocated (true) or not.

    bool local_reached;

    std::vector<typename Digraph::Arc> _stack;

    int _stack_head;

    ///Creates the maps if necessary.

    ///\todo Better memory allocation (instead of new).

    void create_maps() {

      if(!_reached) {

        local_reached = true;

        _reached = Traits::createReachedMap(*_digraph);

      }

    }

  protected:

    DfsVisit() {}

  public:

    typedef DfsVisit Create;

    /// \name Named template parameters

    ///@{

    template <class T>

    struct DefReachedMapTraits : public Traits {

      typedef T ReachedMap;

      static ReachedMap *createReachedMap(const Digraph &digraph) {

        throw UninitializedParameter();

      }

    };

    /// \brief \ref named-templ-param "Named parameter" for setting

    /// ReachedMap type.

    ///