alpar@797: // -*- c++ -*- //
alpar@797: 
alpar@797: /**
alpar@797: @defgroup paths Path Structures
alpar@797: @ingroup datas
alpar@797: \brief Path structures implemented in Hugo.
alpar@797: 
alpar@797: Hugolib provides flexible data structures
alpar@797: to work with paths.
alpar@797: 
alpar@797: All of them have the same interface, especially they can be built or extended
alpar@797: using a standard Builder subclass. This make is easy to have e.g. the Dijkstra
alpar@797: algorithm to store its result in any kind of path structure.
alpar@797: 
alpar@797: */
alpar@797: 
alpar@797: ///\ingroup paths
alpar@797: ///\file
alpar@797: ///\brief Classes for representing paths in graphs.
alpar@797: 
alpar@797: #ifndef HUGO_PATH_H
alpar@797: #define HUGO_PATH_H
alpar@797: 
alpar@797: #include <deque>
alpar@797: #include <vector>
alpar@797: #include <algorithm>
alpar@797: 
alpar@797: #include <hugo/invalid.h>
alpar@797: #include <hugo/error.h>
alpar@797: #include <debug.h>
alpar@797: 
alpar@797: namespace hugo {
alpar@797: 
alpar@797:   /// \addtogroup paths
alpar@797:   /// @{
alpar@797: 
alpar@797: 
alpar@797:   //! \brief A structure for representing directed path in a graph.
alpar@797:   //!
alpar@797:   //! A structure for representing directed path in a graph.
alpar@797:   //! \param Graph The graph type in which the path is.
alpar@797:   //! \param DM DebugMode, defaults to DefaultDebugMode.
alpar@797:   //! 
alpar@797:   //! In a sense, the path can be treated as a graph, for is has \c NodeIt
alpar@797:   //! and \c EdgeIt with the same usage. These types converts to the \c Node
alpar@797:   //! and \c Edge of the original graph.
alpar@797:   //!
alpar@797:   //! \todo Thoroughfully check all the range and consistency tests.
alpar@797:   template<typename Graph, typename DM = DefaultDebugMode>
alpar@797:   class DirPath {
alpar@797:   public:
alpar@797:     /// Edge type of the underlying graph.
alpar@797:     typedef typename Graph::Edge GraphEdge; 
alpar@797:     /// Node type of the underlying graph.
alpar@797:     typedef typename Graph::Node GraphNode;
alpar@797:     class NodeIt;
alpar@797:     class EdgeIt;
alpar@797: 
alpar@797:   protected:
alpar@797:     const Graph *gr;
alpar@797:     typedef std::vector<GraphEdge> Container;
alpar@797:     Container edges;
alpar@797: 
alpar@797:   public:
alpar@797: 
alpar@797:     /// \param _G The graph in which the path is.
alpar@797:     ///
alpar@797:     DirPath(const Graph &_G) : gr(&_G) {}
alpar@797: 
alpar@797:     /// \brief Subpath constructor.
alpar@797:     ///
alpar@797:     /// Subpath defined by two nodes.
alpar@797:     /// \warning It is an error if the two edges are not in order!
alpar@797:     DirPath(const DirPath &P, const NodeIt &a, const NodeIt &b) {
alpar@797:       if( DM::range_check && (!a.valid() || !b.valid) ) {
alpar@797: 	// FIXME: this check should be more elaborate...
alpar@797: 	fault("DirPath, subpath ctor: invalid bounding nodes");
alpar@797:       }
alpar@797:       gr = P.gr;
alpar@797:       edges.insert(edges.end(), P.edges.begin()+a.idx, P.edges.begin()+b.idx);
alpar@797:     }
alpar@797: 
alpar@797:     /// \brief Subpath constructor.
alpar@797:     ///
alpar@797:     /// Subpath defined by two edges. Contains edges in [a,b)
alpar@797:     /// \warning It is an error if the two edges are not in order!
alpar@797:     DirPath(const DirPath &P, const EdgeIt &a, const EdgeIt &b) {
alpar@797:       if( DM::range_check && (!a.valid() || !b.valid) ) {
alpar@797: 	// FIXME: this check should be more elaborate...
alpar@797: 	fault("DirPath, subpath ctor: invalid bounding nodes");
alpar@797:       }
alpar@797:       gr = P.gr;
alpar@797:       edges.insert(edges.end(), P.edges.begin()+a.idx, P.edges.begin()+b.idx);
alpar@797:     }
alpar@797: 
alpar@797:     /// Length of the path.
alpar@797:     size_t length() const { return edges.size(); }
alpar@797:     /// Returns whether the path is empty.
alpar@797:     bool empty() const { return edges.empty(); }
alpar@797: 
alpar@797:     /// Resets the path to an empty path.
alpar@797:     void clear() { edges.clear(); }
alpar@797: 
alpar@797:     /// \brief Starting point of the path.
alpar@797:     ///
alpar@797:     /// Starting point of the path.
alpar@797:     /// Returns INVALID if the path is empty.
alpar@797:     GraphNode from() const {
alpar@797:       return empty() ? INVALID : gr->tail(edges[0]);
alpar@797:     }
alpar@797:     /// \brief End point of the path.
alpar@797:     ///
alpar@797:     /// End point of the path.
alpar@797:     /// Returns INVALID if the path is empty.
alpar@797:     GraphNode to() const {
alpar@797:       return empty() ? INVALID : gr->head(edges[length()-1]);
alpar@797:     }
alpar@797: 
alpar@797:     /// \brief Initializes node or edge iterator to point to the first
alpar@797:     /// node or edge.
alpar@797:     ///
alpar@797:     /// \sa nth
alpar@797:     template<typename It>
alpar@797:     It& first(It &i) const { return i=It(*this); }
alpar@797: 
alpar@797:     /// \brief Initializes node iterator to point to the node of a given index.
alpar@797:     NodeIt& nth(NodeIt &i, int n) const {
alpar@797:       if( DM::range_check && (n<0 || n>int(length())) )
alpar@797: 	fault("DirPath::nth: index out of range");
alpar@797:       return i=NodeIt(*this, n);
alpar@797:     }
alpar@797: 
alpar@797:     /// \brief Initializes edge iterator to point to the edge of a given index.
alpar@797:     EdgeIt& nth(EdgeIt &i, int n) const {
alpar@797:       if( DM::range_check && (n<0 || n>=int(length())) )
alpar@797: 	fault("DirPath::nth: index out of range");
alpar@797:       return i=EdgeIt(*this, n);
alpar@797:     }
alpar@797: 
alpar@797:     /// Checks validity of a node or edge iterator.
alpar@797:     template<typename It>
alpar@797:     static
alpar@797:     bool valid(const It &i) { return i.valid(); }
alpar@797: 
alpar@797:     /// Steps the given node or edge iterator.
alpar@797:     template<typename It>
alpar@797:     static
alpar@797:     It& next(It &e) {
alpar@797:       if( DM::range_check && !e.valid() )
alpar@797: 	fault("DirPath::next() on invalid iterator");
alpar@797:       return ++e;
alpar@797:     }
alpar@797: 
alpar@797:     /// \brief Returns node iterator pointing to the head node of the
alpar@797:     /// given edge iterator.
alpar@797:     NodeIt head(const EdgeIt& e) const {
alpar@797:       if( DM::range_check && !e.valid() )
alpar@797: 	fault("DirPath::head() on invalid iterator");
alpar@797:       return NodeIt(*this, e.idx+1);
alpar@797:     }
alpar@797: 
alpar@797:     /// \brief Returns node iterator pointing to the tail node of the
alpar@797:     /// given edge iterator.
alpar@797:     NodeIt tail(const EdgeIt& e) const {
alpar@797:       if( DM::range_check && !e.valid() )
alpar@797: 	fault("DirPath::tail() on invalid iterator");
alpar@797:       return NodeIt(*this, e.idx);
alpar@797:     }
alpar@797: 
alpar@797: 
alpar@797:     /* Iterator classes */
alpar@797: 
alpar@797:     /**
alpar@797:      * \brief Iterator class to iterate on the edges of the paths
alpar@797:      * 
alpar@797:      * \ingroup paths
alpar@797:      * This class is used to iterate on the edges of the paths
alpar@797:      *
alpar@797:      * Of course it converts to Graph::Edge
alpar@797:      * 
alpar@797:      * \todo Its interface differs from the standard edge iterator.
alpar@797:      * Yes, it shouldn't.
alpar@797:      */
alpar@797:     class EdgeIt {
alpar@797:       friend class DirPath;
alpar@797: 
alpar@797:       int idx;
alpar@797:       const DirPath *p;
alpar@797:     public:
alpar@797:       /// Default constructor
alpar@797:       EdgeIt() {}
alpar@797:       /// Invalid constructor
alpar@797:       EdgeIt(Invalid) : idx(-1), p(0) {}
alpar@797:       /// Constructor with starting point
alpar@797:       EdgeIt(const DirPath &_p, int _idx = 0) :
alpar@797: 	idx(_idx), p(&_p) { validate(); }
alpar@797: 
alpar@797:       ///Validity check
alpar@797:       bool valid() const { return idx!=-1; }
alpar@797: 
alpar@797:       ///Conversion to Graph::Edge
alpar@797:       operator GraphEdge () const {
alpar@797: 	return valid() ? p->edges[idx] : INVALID;
alpar@797:       }
alpar@797: 
alpar@797:       /// Next edge
alpar@797:       EdgeIt& operator++() { ++idx; validate(); return *this; }
alpar@797: 
alpar@797:       /// Comparison operator
alpar@797:       bool operator==(const EdgeIt& e) const { return idx==e.idx; }
alpar@797:       /// Comparison operator
alpar@797:       bool operator!=(const EdgeIt& e) const { return idx!=e.idx; }
alpar@797:       /// Comparison operator
alpar@797:       bool operator<(const EdgeIt& e) const { return idx<e.idx; }
alpar@797: 
alpar@797:     private:
alpar@797:       // FIXME: comparison between signed and unsigned...
alpar@797:       // Jo ez igy? Vagy esetleg legyen a length() int?
alpar@797:       void validate() { if( size_t(idx) >= p->length() ) idx=-1; }
alpar@797:     };
alpar@797: 
alpar@797:     /**
alpar@797:      * \brief Iterator class to iterate on the nodes of the paths
alpar@797:      * 
alpar@797:      * \ingroup paths
alpar@797:      * This class is used to iterate on the nodes of the paths
alpar@797:      *
alpar@797:      * Of course it converts to Graph::Node
alpar@797:      * 
alpar@797:      * \todo Its interface differs from the standard node iterator.
alpar@797:      * Yes, it shouldn't.
alpar@797:      */
alpar@797:     class NodeIt {
alpar@797:       friend class DirPath;
alpar@797: 
alpar@797:       int idx;
alpar@797:       const DirPath *p;
alpar@797:     public:
alpar@797:       /// Default constructor
alpar@797:       NodeIt() {}
alpar@797:       /// Invalid constructor
alpar@797:       NodeIt(Invalid) : idx(-1), p(0) {}
alpar@797:       /// Constructor with starting point
alpar@797:       NodeIt(const DirPath &_p, int _idx = 0) :
alpar@797: 	idx(_idx), p(&_p) { validate(); }
alpar@797: 
alpar@797:       ///Validity check
alpar@797:       bool valid() const { return idx!=-1; }
alpar@797: 
alpar@797:       ///Conversion to Graph::Node
alpar@797:       operator const GraphNode& () const {
alpar@797: 	if(idx >= p->length())
alpar@797: 	  return p->to();
alpar@797: 	else if(idx >= 0)
alpar@797: 	  return p->gr->tail(p->edges[idx]);
alpar@797: 	else
alpar@797: 	  return INVALID;
alpar@797:       }
alpar@797:       /// Next node
alpar@797:       NodeIt& operator++() { ++idx; validate(); return *this; }
alpar@797: 
alpar@797:       /// Comparison operator
alpar@797:       bool operator==(const NodeIt& e) const { return idx==e.idx; }
alpar@797:       /// Comparison operator
alpar@797:       bool operator!=(const NodeIt& e) const { return idx!=e.idx; }
alpar@797:       /// Comparison operator
alpar@797:       bool operator<(const NodeIt& e) const { return idx<e.idx; }
alpar@797: 
alpar@797:     private:
alpar@797:       void validate() { if( size_t(idx) > p->length() ) idx=-1; }
alpar@797:     };
alpar@797: 
alpar@797:     friend class Builder;    
alpar@797: 
alpar@797:     /**
alpar@797:      * \brief Class to build paths
alpar@797:      * 
alpar@797:      * \ingroup paths
alpar@797:      * This class is used to fill a path with edges.
alpar@797:      *
alpar@797:      * You can push new edges to the front and to the back of the path in
alpar@797:      * arbitrary order then you should commit these changes to the graph.
alpar@797:      *
alpar@797:      * Fundamentally, for most "Paths" (classes fulfilling the
alpar@797:      * PathConcept) while the builder is active (after the first modifying
alpar@797:      * operation and until the commit()) the original Path is in a
alpar@797:      * "transitional" state (operations on it have undefined result). But
alpar@797:      * in the case of DirPath the original path remains unchanged until the
alpar@797:      * commit. However we don't recomend that you use this feature.
alpar@797:      */
alpar@797:     class Builder {
alpar@797:       DirPath &P;
alpar@797:       Container front, back;
alpar@797: 
alpar@797:     public:
alpar@797:       ///\param _P the path you want to fill in.
alpar@797:       ///
alpar@797:       Builder(DirPath &_P) : P(_P) {}
alpar@797: 
alpar@797:       /// Sets the starting node of the path.
alpar@797:       
alpar@797:       /// Sets the starting node of the path. Edge added to the path
alpar@797:       /// afterwards have to be incident to this node.
alpar@797:       /// It should be called iff the path is empty and before any call to
alpar@797:       /// \ref pushFront() or \ref pushBack()
alpar@797:       void setStart(const GraphNode &) {}
alpar@797: 
alpar@797:       ///Push a new edge to the front of the path
alpar@797: 
alpar@797:       ///Push a new edge to the front of the path.
alpar@797:       ///\sa setStart
alpar@797:       void pushFront(const GraphEdge& e) {
alpar@797: 	if( DM::consistensy_check && !empty() && P.gr->head(e)!=from() ) {
alpar@797: 	  fault("DirPath::Builder::pushFront: nonincident edge");
alpar@797: 	}
alpar@797: 	front.push_back(e);
alpar@797:       }
alpar@797: 
alpar@797:       ///Push a new edge to the back of the path
alpar@797: 
alpar@797:       ///Push a new edge to the back of the path.
alpar@797:       ///\sa setStart
alpar@797:       void pushBack(const GraphEdge& e) {
alpar@797: 	if( DM::consistensy_check && !empty() && P.gr->tail(e)!=to() ) {
alpar@797: 	  fault("DirPath::Builder::pushBack: nonincident edge");
alpar@797: 	}
alpar@797: 	back.push_back(e);
alpar@797:       }
alpar@797: 
alpar@797:       ///Commit the changes to the path.
alpar@797:       void commit() {
alpar@797: 	if( !(front.empty() && back.empty()) ) {
alpar@797: 	  Container tmp;
alpar@797: 	  tmp.reserve(front.size()+back.size()+P.length());
alpar@797: 	  tmp.insert(tmp.end(), front.rbegin(), front.rend());
alpar@797: 	  tmp.insert(tmp.end(), P.edges.begin(), P.edges.end());
alpar@797: 	  tmp.insert(tmp.end(), back.begin(), back.end());
alpar@797: 	  P.edges.swap(tmp);
alpar@797: 	  front.clear();
alpar@797: 	  back.clear();
alpar@797: 	}
alpar@797:       }
alpar@797: 
alpar@797:       // FIXME: Hmm, pontosan hogy is kene ezt csinalni?
alpar@797:       // Hogy kenyelmes egy ilyet hasznalni?
alpar@797:   
alpar@797:       ///Reserve storage in advance for the builder
alpar@797: 
alpar@797:       ///If you know an reasonable upper bound of the number of the edges
alpar@797:       ///to add, using this function you can speed up the building.
alpar@797:       void reserve(size_t r) {
alpar@797: 	front.reserve(r);
alpar@797: 	back.reserve(r);
alpar@797:       }
alpar@797: 
alpar@797:     private:
alpar@797:       bool empty() {
alpar@797: 	return front.empty() && back.empty() && P.empty();
alpar@797:       }
alpar@797: 
alpar@797:       GraphNode from() const {
alpar@797: 	if( ! front.empty() )
alpar@797: 	  return P.gr->tail(front[front.size()-1]);
alpar@797: 	else if( ! P.empty() )
alpar@797: 	  return P.gr->tail(P.edges[0]);
alpar@797: 	else if( ! back.empty() )
alpar@797: 	  return P.gr->tail(back[0]);
alpar@797: 	else
alpar@797: 	  return INVALID;
alpar@797:       }
alpar@797:       GraphNode to() const {
alpar@797: 	if( ! back.empty() )
alpar@797: 	  return P.gr->head(back[back.size()-1]);
alpar@797: 	else if( ! P.empty() )
alpar@797: 	  return P.gr->head(P.edges[P.length()-1]);
alpar@797: 	else if( ! front.empty() )
alpar@797: 	  return P.gr->head(front[0]);
alpar@797: 	else
alpar@797: 	  return INVALID;
alpar@797:       }
alpar@797: 
alpar@797:     };
alpar@797: 
alpar@797:   };
alpar@797: 
alpar@797: 
alpar@797: 
alpar@797: 
alpar@797: 
alpar@797: 
alpar@797: 
alpar@797: 
alpar@797: 
alpar@797: 
alpar@797:   /**********************************************************************/
alpar@797: 
alpar@797: 
alpar@797:   //! \brief A structure for representing undirected path in a graph.
alpar@797:   //!
alpar@797:   //! A structure for representing undirected path in a graph. Ie. this is
alpar@797:   //! a path in a \e directed graph but the edges should not be directed
alpar@797:   //! forward.
alpar@797:   //!
alpar@797:   //! \param Graph The graph type in which the path is.
alpar@797:   //! \param DM DebugMode, defaults to DefaultDebugMode.
alpar@797:   //! 
alpar@797:   //! In a sense, the path can be treated as a graph, for is has \c NodeIt
alpar@797:   //! and \c EdgeIt with the same usage. These types converts to the \c Node
alpar@797:   //! and \c Edge of the original graph.
alpar@797:   //!
alpar@797:   //! \todo Thoroughfully check all the range and consistency tests.
alpar@797:   template<typename Graph, typename DM = DefaultDebugMode>
alpar@797:   class UndirPath {
alpar@797:   public:
alpar@797:     /// Edge type of the underlying graph.
alpar@797:     typedef typename Graph::Edge GraphEdge;
alpar@797:      /// Node type of the underlying graph.
alpar@797:    typedef typename Graph::Node GraphNode;
alpar@797:     class NodeIt;
alpar@797:     class EdgeIt;
alpar@797: 
alpar@797:   protected:
alpar@797:     const Graph *gr;
alpar@797:     typedef std::vector<GraphEdge> Container;
alpar@797:     Container edges;
alpar@797: 
alpar@797:   public:
alpar@797: 
alpar@797:     /// \param _G The graph in which the path is.
alpar@797:     ///
alpar@797:     UndirPath(const Graph &_G) : gr(&_G) {}
alpar@797: 
alpar@797:     /// \brief Subpath constructor.
alpar@797:     ///
alpar@797:     /// Subpath defined by two nodes.
alpar@797:     /// \warning It is an error if the two edges are not in order!
alpar@797:     UndirPath(const UndirPath &P, const NodeIt &a, const NodeIt &b) {
alpar@797:       if( DM::range_check && (!a.valid() || !b.valid) ) {
alpar@797: 	// FIXME: this check should be more elaborate...
alpar@797: 	fault("UndirPath, subpath ctor: invalid bounding nodes");
alpar@797:       }
alpar@797:       gr = P.gr;
alpar@797:       edges.insert(edges.end(), P.edges.begin()+a.idx, P.edges.begin()+b.idx);
alpar@797:     }
alpar@797: 
alpar@797:     /// \brief Subpath constructor.
alpar@797:     ///
alpar@797:     /// Subpath defined by two edges. Contains edges in [a,b)
alpar@797:     /// \warning It is an error if the two edges are not in order!
alpar@797:     UndirPath(const UndirPath &P, const EdgeIt &a, const EdgeIt &b) {
alpar@797:       if( DM::range_check && (!a.valid() || !b.valid) ) {
alpar@797: 	// FIXME: this check should be more elaborate...
alpar@797: 	fault("UndirPath, subpath ctor: invalid bounding nodes");
alpar@797:       }
alpar@797:       gr = P.gr;
alpar@797:       edges.insert(edges.end(), P.edges.begin()+a.idx, P.edges.begin()+b.idx);
alpar@797:     }
alpar@797: 
alpar@797:     /// Length of the path.
alpar@797:     size_t length() const { return edges.size(); }
alpar@797:     /// Returns whether the path is empty.
alpar@797:     bool empty() const { return edges.empty(); }
alpar@797: 
alpar@797:     /// Resets the path to an empty path.
alpar@797:     void clear() { edges.clear(); }
alpar@797: 
alpar@797:     /// \brief Starting point of the path.
alpar@797:     ///
alpar@797:     /// Starting point of the path.
alpar@797:     /// Returns INVALID if the path is empty.
alpar@797:     GraphNode from() const {
alpar@797:       return empty() ? INVALID : gr->tail(edges[0]);
alpar@797:     }
alpar@797:     /// \brief End point of the path.
alpar@797:     ///
alpar@797:     /// End point of the path.
alpar@797:     /// Returns INVALID if the path is empty.
alpar@797:     GraphNode to() const {
alpar@797:       return empty() ? INVALID : gr->head(edges[length()-1]);
alpar@797:     }
alpar@797: 
alpar@797:     /// \brief Initializes node or edge iterator to point to the first
alpar@797:     /// node or edge.
alpar@797:     ///
alpar@797:     /// \sa nth
alpar@797:     template<typename It>
alpar@797:     It& first(It &i) const { return i=It(*this); }
alpar@797: 
alpar@797:     /// \brief Initializes node iterator to point to the node of a given index.
alpar@797:     NodeIt& nth(NodeIt &i, int n) const {
alpar@797:       if( DM::range_check && (n<0 || n>int(length())) )
alpar@797: 	fault("UndirPath::nth: index out of range");
alpar@797:       return i=NodeIt(*this, n);
alpar@797:     }
alpar@797: 
alpar@797:     /// \brief Initializes edge iterator to point to the edge of a given index.
alpar@797:     EdgeIt& nth(EdgeIt &i, int n) const {
alpar@797:       if( DM::range_check && (n<0 || n>=int(length())) )
alpar@797: 	fault("UndirPath::nth: index out of range");
alpar@797:       return i=EdgeIt(*this, n);
alpar@797:     }
alpar@797: 
alpar@797:     /// Checks validity of a node or edge iterator.
alpar@797:     template<typename It>
alpar@797:     static
alpar@797:     bool valid(const It &i) { return i.valid(); }
alpar@797: 
alpar@797:     /// Steps the given node or edge iterator.
alpar@797:     template<typename It>
alpar@797:     static
alpar@797:     It& next(It &e) {
alpar@797:       if( DM::range_check && !e.valid() )
alpar@797: 	fault("UndirPath::next() on invalid iterator");
alpar@797:       return ++e;
alpar@797:     }
alpar@797: 
alpar@797:     /// \brief Returns node iterator pointing to the head node of the
alpar@797:     /// given edge iterator.
alpar@797:     NodeIt head(const EdgeIt& e) const {
alpar@797:       if( DM::range_check && !e.valid() )
alpar@797: 	fault("UndirPath::head() on invalid iterator");
alpar@797:       return NodeIt(*this, e.idx+1);
alpar@797:     }
alpar@797: 
alpar@797:     /// \brief Returns node iterator pointing to the tail node of the
alpar@797:     /// given edge iterator.
alpar@797:     NodeIt tail(const EdgeIt& e) const {
alpar@797:       if( DM::range_check && !e.valid() )
alpar@797: 	fault("UndirPath::tail() on invalid iterator");
alpar@797:       return NodeIt(*this, e.idx);
alpar@797:     }
alpar@797: 
alpar@797: 
alpar@797: 
alpar@797:     /**
alpar@797:      * \brief Iterator class to iterate on the edges of the paths
alpar@797:      * 
alpar@797:      * \ingroup paths
alpar@797:      * This class is used to iterate on the edges of the paths
alpar@797:      *
alpar@797:      * Of course it converts to Graph::Edge
alpar@797:      * 
alpar@797:      * \todo Its interface differs from the standard edge iterator.
alpar@797:      * Yes, it shouldn't.
alpar@797:      */
alpar@797:     class EdgeIt {
alpar@797:       friend class UndirPath;
alpar@797: 
alpar@797:       int idx;
alpar@797:       const UndirPath *p;
alpar@797:     public:
alpar@797:       /// Default constructor
alpar@797:       EdgeIt() {}
alpar@797:       /// Invalid constructor
alpar@797:       EdgeIt(Invalid) : idx(-1), p(0) {}
alpar@797:       /// Constructor with starting point
alpar@797:       EdgeIt(const UndirPath &_p, int _idx = 0) :
alpar@797: 	idx(_idx), p(&_p) { validate(); }
alpar@797: 
alpar@797:       ///Validity check
alpar@797:       bool valid() const { return idx!=-1; }
alpar@797: 
alpar@797:       ///Conversion to Graph::Edge
alpar@797:       operator GraphEdge () const {
alpar@797: 	return valid() ? p->edges[idx] : INVALID;
alpar@797:       }
alpar@797:       /// Next edge
alpar@797:      EdgeIt& operator++() { ++idx; validate(); return *this; }
alpar@797: 
alpar@797:       /// Comparison operator
alpar@797:       bool operator==(const EdgeIt& e) const { return idx==e.idx; }
alpar@797:       /// Comparison operator
alpar@797:       bool operator!=(const EdgeIt& e) const { return idx!=e.idx; }
alpar@797:       /// Comparison operator
alpar@797:       bool operator<(const EdgeIt& e) const { return idx<e.idx; }
alpar@797: 
alpar@797:     private:
alpar@797:       // FIXME: comparison between signed and unsigned...
alpar@797:       // Jo ez igy? Vagy esetleg legyen a length() int?
alpar@797:       void validate() { if( size_t(idx) >= p->length() ) idx=-1; }
alpar@797:     };
alpar@797: 
alpar@797:     /**
alpar@797:      * \brief Iterator class to iterate on the nodes of the paths
alpar@797:      * 
alpar@797:      * \ingroup paths
alpar@797:      * This class is used to iterate on the nodes of the paths
alpar@797:      *
alpar@797:      * Of course it converts to Graph::Node
alpar@797:      * 
alpar@797:      * \todo Its interface differs from the standard node iterator.
alpar@797:      * Yes, it shouldn't.
alpar@797:      */
alpar@797:     class NodeIt {
alpar@797:       friend class UndirPath;
alpar@797: 
alpar@797:       int idx;
alpar@797:       const UndirPath *p;
alpar@797:     public:
alpar@797:       /// Default constructor
alpar@797:       NodeIt() {}
alpar@797:       /// Invalid constructor
alpar@797:       NodeIt(Invalid) : idx(-1), p(0) {}
alpar@797:       /// Constructor with starting point
alpar@797:       NodeIt(const UndirPath &_p, int _idx = 0) :
alpar@797: 	idx(_idx), p(&_p) { validate(); }
alpar@797: 
alpar@797:       ///Validity check
alpar@797:       bool valid() const { return idx!=-1; }
alpar@797: 
alpar@797:       ///Conversion to Graph::Node
alpar@797:       operator const GraphNode& () const {
alpar@797: 	if(idx >= p->length())
alpar@797: 	  return p->to();
alpar@797: 	else if(idx >= 0)
alpar@797: 	  return p->gr->tail(p->edges[idx]);
alpar@797: 	else
alpar@797: 	  return INVALID;
alpar@797:       }
alpar@797:       /// Next node
alpar@797:       NodeIt& operator++() { ++idx; validate(); return *this; }
alpar@797: 
alpar@797:       /// Comparison operator
alpar@797:       bool operator==(const NodeIt& e) const { return idx==e.idx; }
alpar@797:       /// Comparison operator
alpar@797:       bool operator!=(const NodeIt& e) const { return idx!=e.idx; }
alpar@797:        /// Comparison operator
alpar@797:      bool operator<(const NodeIt& e) const { return idx<e.idx; }
alpar@797: 
alpar@797:     private:
alpar@797:       void validate() { if( size_t(idx) > p->length() ) idx=-1; }
alpar@797:     };
alpar@797: 
alpar@797:     friend class Builder;    
alpar@797: 
alpar@797:     /**
alpar@797:      * \brief Class to build paths
alpar@797:      * 
alpar@797:      * \ingroup paths
alpar@797:      * This class is used to fill a path with edges.
alpar@797:      *
alpar@797:      * You can push new edges to the front and to the back of the path in
alpar@797:      * arbitrary order then you should commit these changes to the graph.
alpar@797:      *
alpar@797:      * Fundamentally, for most "Paths" (classes fulfilling the
alpar@797:      * PathConcept) while the builder is active (after the first modifying
alpar@797:      * operation and until the commit()) the original Path is in a
alpar@797:      * "transitional" state (operations ot it have undefined result). But
alpar@797:      * in the case of UndirPath the original path is unchanged until the
alpar@797:      * commit. However we don't recomend that you use this feature.
alpar@797:      */
alpar@797:     class Builder {
alpar@797:       UndirPath &P;
alpar@797:       Container front, back;
alpar@797: 
alpar@797:     public:
alpar@797:       ///\param _P the path you want to fill in.
alpar@797:       ///
alpar@797:       Builder(UndirPath &_P) : P(_P) {}
alpar@797: 
alpar@797:       /// Sets the starting node of the path.
alpar@797:       
alpar@797:       /// Sets the starting node of the path. Edge added to the path
alpar@797:       /// afterwards have to be incident to this node.
alpar@797:       /// It should be called iff the path is empty and before any call to
alpar@797:       /// \ref pushFront() or \ref pushBack()
alpar@797:       void setStart(const GraphNode &) {}
alpar@797: 
alpar@797:       ///Push a new edge to the front of the path
alpar@797: 
alpar@797:       ///Push a new edge to the front of the path.
alpar@797:       ///\sa setStart
alpar@797:       void pushFront(const GraphEdge& e) {
alpar@797: 	if( DM::consistensy_check && !empty() && P.gr->head(e)!=from() ) {
alpar@797: 	  fault("UndirPath::Builder::pushFront: nonincident edge");
alpar@797: 	}
alpar@797: 	front.push_back(e);
alpar@797:       }
alpar@797: 
alpar@797:       ///Push a new edge to the back of the path
alpar@797: 
alpar@797:       ///Push a new edge to the back of the path.
alpar@797:       ///\sa setStart
alpar@797:       void pushBack(const GraphEdge& e) {
alpar@797: 	if( DM::consistensy_check && !empty() && P.gr->tail(e)!=to() ) {
alpar@797: 	  fault("UndirPath::Builder::pushBack: nonincident edge");
alpar@797: 	}
alpar@797: 	back.push_back(e);
alpar@797:       }
alpar@797: 
alpar@797:       ///Commit the changes to the path.
alpar@797:       void commit() {
alpar@797: 	if( !(front.empty() && back.empty()) ) {
alpar@797: 	  Container tmp;
alpar@797: 	  tmp.reserve(front.size()+back.size()+P.length());
alpar@797: 	  tmp.insert(tmp.end(), front.rbegin(), front.rend());
alpar@797: 	  tmp.insert(tmp.end(), P.edges.begin(), P.edges.end());
alpar@797: 	  tmp.insert(tmp.end(), back.begin(), back.end());
alpar@797: 	  P.edges.swap(tmp);
alpar@797: 	  front.clear();
alpar@797: 	  back.clear();
alpar@797: 	}
alpar@797:       }
alpar@797: 
alpar@797:       // FIXME: Hmm, pontosan hogy is kene ezt csinalni?
alpar@797:       // Hogy kenyelmes egy ilyet hasznalni?
alpar@797: 
alpar@797:       ///Reserve storage in advance for the builder
alpar@797: 
alpar@797:       ///If you know an reasonable upper bound of the number of the edges
alpar@797:       ///to add, using this function you can speed up the building.
alpar@797:        void reserve(size_t r) {
alpar@797: 	front.reserve(r);
alpar@797: 	back.reserve(r);
alpar@797:       }
alpar@797: 
alpar@797:     private:
alpar@797:       bool empty() {
alpar@797: 	return front.empty() && back.empty() && P.empty();
alpar@797:       }
alpar@797: 
alpar@797:       GraphNode from() const {
alpar@797: 	if( ! front.empty() )
alpar@797: 	  return P.gr->tail(front[front.size()-1]);
alpar@797: 	else if( ! P.empty() )
alpar@797: 	  return P.gr->tail(P.edges[0]);
alpar@797: 	else if( ! back.empty() )
alpar@797: 	  return P.gr->tail(back[0]);
alpar@797: 	else
alpar@797: 	  return INVALID;
alpar@797:       }
alpar@797:       GraphNode to() const {
alpar@797: 	if( ! back.empty() )
alpar@797: 	  return P.gr->head(back[back.size()-1]);
alpar@797: 	else if( ! P.empty() )
alpar@797: 	  return P.gr->head(P.edges[P.length()-1]);
alpar@797: 	else if( ! front.empty() )
alpar@797: 	  return P.gr->head(front[0]);
alpar@797: 	else
alpar@797: 	  return INVALID;
alpar@797:       }
alpar@797: 
alpar@797:     };
alpar@797: 
alpar@797:   };
alpar@797: 
alpar@797: 
alpar@797: 
alpar@797: 
alpar@797: 
alpar@797: 
alpar@797: 
alpar@797: 
alpar@797: 
alpar@797: 
alpar@797:   /**********************************************************************/
alpar@797: 
alpar@797: 
alpar@797:   /* Ennek az allocatorosdinak sokkal jobban utana kene nezni a hasznalata
alpar@797:      elott. Eleg bonyinak nez ki, ahogyan azokat az STL-ben hasznaljak. */
alpar@797: 
alpar@797:   template<typename Graph>
alpar@797:   class DynamicPath {
alpar@797: 
alpar@797:   public:
alpar@797:     typedef typename Graph::Edge GraphEdge;
alpar@797:     typedef typename Graph::Node GraphNode;
alpar@797:     class NodeIt;
alpar@797:     class EdgeIt;
alpar@797: 
alpar@797:   protected:
alpar@797:     Graph& G;
alpar@797:     // FIXME: ehelyett eleg lenne tarolni ket boolt: a ket szelso el
alpar@797:     // iranyitasat:
alpar@797:     GraphNode _first, _last;
alpar@797:     typedef std::deque<GraphEdge> Container;
alpar@797:     Container edges;
alpar@797: 
alpar@797:   public:
alpar@797: 
alpar@797:     DynamicPath(Graph &_G) : G(_G), _first(INVALID), _last(INVALID) {}
alpar@797: 
alpar@797:     /// Subpath defined by two nodes.
alpar@797:     /// Nodes may be in reversed order, then
alpar@797:     /// we contstruct the reversed path.
alpar@797:     DynamicPath(const DynamicPath &P, const NodeIt &a, const NodeIt &b);
alpar@797:     /// Subpath defined by two edges. Contains edges in [a,b)
alpar@797:     /// It is an error if the two edges are not in order!
alpar@797:     DynamicPath(const DynamicPath &P, const EdgeIt &a, const EdgeIt &b);
alpar@797:     
alpar@797:     size_t length() const { return edges.size(); }
alpar@797:     GraphNode from() const { return _first; }
alpar@797:     GraphNode to() const { return _last; }
alpar@797: 
alpar@797:     NodeIt& first(NodeIt &n) const { return nth(n, 0); }
alpar@797:     EdgeIt& first(EdgeIt &e) const { return nth(e, 0); }
alpar@797:     template<typename It>
alpar@797:     It first() const { 
alpar@797:       It e;
alpar@797:       first(e);
alpar@797:       return e; 
alpar@797:     }
alpar@797: 
alpar@797:     NodeIt& nth(NodeIt &, size_t) const;
alpar@797:     EdgeIt& nth(EdgeIt &, size_t) const;
alpar@797:     template<typename It>
alpar@797:     It nth(size_t n) const { 
alpar@797:       It e;
alpar@797:       nth(e, n);
alpar@797:       return e; 
alpar@797:     }
alpar@797: 
alpar@797:     bool valid(const NodeIt &n) const { return n.idx <= length(); }
alpar@797:     bool valid(const EdgeIt &e) const { return e.it < edges.end(); }
alpar@797: 
alpar@797:     bool isForward(const EdgeIt &e) const { return e.forw; }
alpar@797: 
alpar@797:     /// index of a node on the path. Returns length+2 for the invalid NodeIt
alpar@797:     int index(const NodeIt &n) const { return n.idx; }
alpar@797:     /// index of an edge on the path. Returns length+1 for the invalid EdgeIt
alpar@797:     int index(const EdgeIt &e) const { return e.it - edges.begin(); }
alpar@797: 
alpar@797:     EdgeIt& next(EdgeIt &e) const;
alpar@797:     NodeIt& next(NodeIt &n) const;
alpar@797:     template <typename It>
alpar@797:     It getNext(It it) const {
alpar@797:       It tmp(it); return next(tmp);
alpar@797:     }
alpar@797: 
alpar@797:     // A path is constructed using the following four functions.
alpar@797:     // They return false if the requested operation is inconsistent
alpar@797:     // with the path constructed so far.
alpar@797:     // If your path has only one edge you MUST set either "from" or "to"!
alpar@797:     // So you probably SHOULD call it in any case to be safe (and check the
alpar@797:     // returned value to check if your path is consistent with your idea).
alpar@797:     bool pushFront(const GraphEdge &e);
alpar@797:     bool pushBack(const GraphEdge &e);
alpar@797:     bool setFrom(const GraphNode &n);
alpar@797:     bool setTo(const GraphNode &n);
alpar@797: 
alpar@797:     // WARNING: these two functions return the head/tail of an edge with
alpar@797:     // respect to the direction of the path!
alpar@797:     // So G.head(P.graphEdge(e)) == P.graphNode(P.head(e)) holds only if 
alpar@797:     // P.forward(e) is true (or the edge is a loop)!
alpar@797:     NodeIt head(const EdgeIt& e) const;
alpar@797:     NodeIt tail(const EdgeIt& e) const;
alpar@797: 
alpar@797:     // FIXME: ezeknek valami jobb nev kellene!!!
alpar@797:     GraphEdge graphEdge(const EdgeIt& e) const;
alpar@797:     GraphNode graphNode(const NodeIt& n) const;
alpar@797: 
alpar@797: 
alpar@797:     /*** Iterator classes ***/
alpar@797:     class EdgeIt {
alpar@797:       friend class DynamicPath;
alpar@797: 
alpar@797:       typename Container::const_iterator it;
alpar@797:       bool forw;
alpar@797:     public:
alpar@797:       // FIXME: jarna neki ilyen is...
alpar@797:       // EdgeIt(Invalid);
alpar@797: 
alpar@797:       bool forward() const { return forw; }
alpar@797: 
alpar@797:       bool operator==(const EdgeIt& e) const { return it==e.it; }
alpar@797:       bool operator!=(const EdgeIt& e) const { return it!=e.it; }
alpar@797:       bool operator<(const EdgeIt& e) const { return it<e.it; }
alpar@797:     };
alpar@797: 
alpar@797:     class NodeIt {
alpar@797:       friend class DynamicPath;
alpar@797: 
alpar@797:       size_t idx;
alpar@797:       bool tail;  // Is this node the tail of the edge with same idx?
alpar@797: 
alpar@797:     public:
alpar@797:       // FIXME: jarna neki ilyen is...
alpar@797:       // NodeIt(Invalid);
alpar@797: 
alpar@797:       bool operator==(const NodeIt& n) const { return idx==n.idx; }
alpar@797:       bool operator!=(const NodeIt& n) const { return idx!=n.idx; }
alpar@797:       bool operator<(const NodeIt& n) const { return idx<n.idx; }
alpar@797:     };
alpar@797: 
alpar@797:   private:
alpar@797:     bool edgeIncident(const GraphEdge &e, const GraphNode &a,
alpar@797: 		      GraphNode &b);
alpar@797:     bool connectTwoEdges(const GraphEdge &e, const GraphEdge &f);
alpar@797:   };
alpar@797: 
alpar@797:   template<typename Gr>
alpar@797:   typename DynamicPath<Gr>::EdgeIt&
alpar@797:   DynamicPath<Gr>::next(DynamicPath::EdgeIt &e) const {
alpar@797:     if( e.it == edges.end() ) 
alpar@797:       return e;
alpar@797: 
alpar@797:     GraphNode common_node = ( e.forw ? G.head(*e.it) : G.tail(*e.it) );
alpar@797:     ++e.it;
alpar@797: 
alpar@797:     // Invalid edgeit is always forward :)
alpar@797:     if( e.it == edges.end() ) {
alpar@797:       e.forw = true;
alpar@797:       return e;
alpar@797:     }
alpar@797: 
alpar@797:     e.forw = ( G.tail(*e.it) == common_node );
alpar@797:     return e;
alpar@797:   }
alpar@797: 
alpar@797:   template<typename Gr>
alpar@797:   typename DynamicPath<Gr>::NodeIt& DynamicPath<Gr>::next(NodeIt &n) const {
alpar@797:     if( n.idx >= length() ) {
alpar@797:       // FIXME: invalid
alpar@797:       n.idx = length()+1;
alpar@797:       return n;
alpar@797:     }
alpar@797: 
alpar@797:     
alpar@797:     GraphNode next_node = ( n.tail ? G.head(edges[n.idx]) :
alpar@797: 			      G.tail(edges[n.idx]) );
alpar@797:     ++n.idx;
alpar@797:     if( n.idx < length() ) {
alpar@797:       n.tail = ( next_node == G.tail(edges[n.idx]) );
alpar@797:     }
alpar@797:     else {
alpar@797:       n.tail = true;
alpar@797:     }
alpar@797: 
alpar@797:     return n;
alpar@797:   }
alpar@797: 
alpar@797:   template<typename Gr>
alpar@797:   bool DynamicPath<Gr>::edgeIncident(const GraphEdge &e, const GraphNode &a,
alpar@797: 			  GraphNode &b) {
alpar@797:     if( G.tail(e) == a ) {
alpar@797:       b=G.head(e);
alpar@797:       return true;
alpar@797:     }
alpar@797:     if( G.head(e) == a ) {
alpar@797:       b=G.tail(e);
alpar@797:       return true;
alpar@797:     }
alpar@797:     return false;
alpar@797:   }
alpar@797: 
alpar@797:   template<typename Gr>
alpar@797:   bool DynamicPath<Gr>::connectTwoEdges(const GraphEdge &e,
alpar@797: 			     const GraphEdge &f) {
alpar@797:     if( edgeIncident(f, G.tail(e), _last) ) {
alpar@797:       _first = G.head(e);
alpar@797:       return true;
alpar@797:     }
alpar@797:     if( edgeIncident(f, G.head(e), _last) ) {
alpar@797:       _first = G.tail(e);
alpar@797:       return true;
alpar@797:     }
alpar@797:     return false;
alpar@797:   }
alpar@797: 
alpar@797:   template<typename Gr>
alpar@797:   bool DynamicPath<Gr>::pushFront(const GraphEdge &e) {
alpar@797:     if( G.valid(_first) ) {
alpar@797: 	if( edgeIncident(e, _first, _first) ) {
alpar@797: 	  edges.push_front(e);
alpar@797: 	  return true;
alpar@797: 	}
alpar@797: 	else
alpar@797: 	  return false;
alpar@797:     }
alpar@797:     else if( length() < 1 || connectTwoEdges(e, edges[0]) ) {
alpar@797:       edges.push_front(e);
alpar@797:       return true;
alpar@797:     }
alpar@797:     else
alpar@797:       return false;
alpar@797:   }
alpar@797: 
alpar@797:   template<typename Gr>
alpar@797:   bool DynamicPath<Gr>::pushBack(const GraphEdge &e) {
alpar@797:     if( G.valid(_last) ) {
alpar@797: 	if( edgeIncident(e, _last, _last) ) {
alpar@797: 	  edges.push_back(e);
alpar@797: 	  return true;
alpar@797: 	}
alpar@797: 	else
alpar@797: 	  return false;
alpar@797:     }
alpar@797:     else if( length() < 1 || connectTwoEdges(edges[0], e) ) {
alpar@797:       edges.push_back(e);
alpar@797:       return true;
alpar@797:     }
alpar@797:     else
alpar@797:       return false;
alpar@797:   }
alpar@797: 
alpar@797: 
alpar@797:   template<typename Gr>
alpar@797:   bool DynamicPath<Gr>::setFrom(const GraphNode &n) {
alpar@797:     if( G.valid(_first) ) {
alpar@797:       return _first == n;
alpar@797:     }
alpar@797:     else {
alpar@797:       if( length() > 0) {
alpar@797: 	if( edgeIncident(edges[0], n, _last) ) {
alpar@797: 	  _first = n;
alpar@797: 	  return true;
alpar@797: 	}
alpar@797: 	else return false;
alpar@797:       }
alpar@797:       else {
alpar@797: 	_first = _last = n;
alpar@797: 	return true;
alpar@797:       }
alpar@797:     }
alpar@797:   }
alpar@797: 
alpar@797:   template<typename Gr>
alpar@797:   bool DynamicPath<Gr>::setTo(const GraphNode &n) {
alpar@797:     if( G.valid(_last) ) {
alpar@797:       return _last == n;
alpar@797:     }
alpar@797:     else {
alpar@797:       if( length() > 0) {
alpar@797: 	if( edgeIncident(edges[0], n, _first) ) {
alpar@797: 	  _last = n;
alpar@797: 	  return true;
alpar@797: 	}
alpar@797: 	else return false;
alpar@797:       }
alpar@797:       else {
alpar@797: 	_first = _last = n;
alpar@797: 	return true;
alpar@797:       }
alpar@797:     }
alpar@797:   }
alpar@797: 
alpar@797: 
alpar@797:   template<typename Gr>
alpar@797:   typename DynamicPath<Gr>::NodeIt
alpar@797:   DynamicPath<Gr>::tail(const EdgeIt& e) const {
alpar@797:     NodeIt n;
alpar@797: 
alpar@797:     if( e.it == edges.end() ) {
alpar@797:       // FIXME: invalid-> invalid
alpar@797:       n.idx = length() + 1;
alpar@797:       n.tail = true;
alpar@797:       return n;
alpar@797:     }
alpar@797: 
alpar@797:     n.idx = e.it-edges.begin();
alpar@797:     n.tail = e.forw;
alpar@797:     return n;
alpar@797:   }
alpar@797: 
alpar@797:   template<typename Gr>
alpar@797:   typename DynamicPath<Gr>::NodeIt
alpar@797:   DynamicPath<Gr>::head(const EdgeIt& e) const {
alpar@797:     if( e.it == edges.end()-1 ) {
alpar@797:       return _last;
alpar@797:     }
alpar@797: 
alpar@797:     EdgeIt next_edge = e;
alpar@797:     next(next_edge);
alpar@797:     return tail(next_edge);
alpar@797:   }
alpar@797:       
alpar@797:   template<typename Gr>
alpar@797:   typename DynamicPath<Gr>::GraphEdge
alpar@797:   DynamicPath<Gr>::graphEdge(const EdgeIt& e) const {
alpar@797:     if( e.it != edges.end() ) {
alpar@797:       return *e.it;
alpar@797:     }
alpar@797:     else {
alpar@797:       return INVALID;
alpar@797:     }
alpar@797:   }
alpar@797:   
alpar@797:   template<typename Gr>
alpar@797:   typename DynamicPath<Gr>::GraphNode
alpar@797:   DynamicPath<Gr>::graphNode(const NodeIt& n) const {
alpar@797:     if( n.idx < length() ) {
alpar@797:       return n.tail ? G.tail(edges[n.idx]) : G.head(edges[n.idx]);
alpar@797:     }
alpar@797:     else if( n.idx == length() ) {
alpar@797:       return _last;
alpar@797:     }
alpar@797:     else {
alpar@797:       return INVALID;
alpar@797:     }
alpar@797:   }
alpar@797: 
alpar@797:   template<typename Gr>
alpar@797:   typename DynamicPath<Gr>::EdgeIt&
alpar@797:   DynamicPath<Gr>::nth(EdgeIt &e, size_t k) const {
alpar@797:     if( k>=length() ) {
alpar@797:       // FIXME: invalid EdgeIt
alpar@797:       e.it = edges.end();
alpar@797:       e.forw = true;
alpar@797:       return e;
alpar@797:     }
alpar@797: 
alpar@797:     e.it = edges.begin()+k;
alpar@797:     if(k==0) {
alpar@797:       e.forw = ( G.tail(*e.it) == _first );
alpar@797:     }
alpar@797:     else {
alpar@797:       e.forw = ( G.tail(*e.it) == G.tail(edges[k-1]) ||
alpar@797: 		 G.tail(*e.it) == G.head(edges[k-1]) );
alpar@797:     }
alpar@797:     return e;
alpar@797:   }
alpar@797:     
alpar@797:   template<typename Gr>
alpar@797:   typename DynamicPath<Gr>::NodeIt&
alpar@797:   DynamicPath<Gr>::nth(NodeIt &n, size_t k) const {
alpar@797:     if( k>length() ) {
alpar@797:       // FIXME: invalid NodeIt
alpar@797:       n.idx = length()+1;
alpar@797:       n.tail = true;
alpar@797:       return n;
alpar@797:     }
alpar@797:     if( k==length() ) {
alpar@797:       n.idx = length();
alpar@797:       n.tail = true;
alpar@797:       return n;
alpar@797:     }
alpar@797:     n = tail(nth<EdgeIt>(k));
alpar@797:     return n;
alpar@797:   }
alpar@797: 
alpar@797:   // Reszut konstruktorok:
alpar@797: 
alpar@797: 
alpar@797:   template<typename Gr>
alpar@797:   DynamicPath<Gr>::DynamicPath(const DynamicPath &P, const EdgeIt &a,
alpar@797: 			       const EdgeIt &b) :
alpar@797:     G(P.G), edges(a.it, b.it)    // WARNING: if b.it < a.it this will blow up! 
alpar@797:   {
alpar@797:     if( G.valid(P._first) && a.it < P.edges.end() ) {
alpar@797:       _first = ( a.forw ? G.tail(*a.it) : G.head(*a.it) );
alpar@797:       if( b.it < P.edges.end() ) {
alpar@797: 	_last = ( b.forw ? G.tail(*b.it) : G.head(*b.it) );
alpar@797:       }
alpar@797:       else {
alpar@797: 	_last = P._last;
alpar@797:       }
alpar@797:     }
alpar@797:   }
alpar@797: 
alpar@797:   template<typename Gr>
alpar@797:   DynamicPath<Gr>::DynamicPath(const DynamicPath &P, const NodeIt &a,
alpar@797: 			       const NodeIt &b) : G(P.G)
alpar@797:   {
alpar@797:     if( !P.valid(a) || !P.valid(b) )
alpar@797:       return;
alpar@797: 
alpar@797:     int ai = a.idx, bi = b.idx;
alpar@797:     if( bi<ai )
alpar@797:       std::swap(ai,bi);
alpar@797:     
alpar@797:     edges.resize(bi-ai);
alpar@797:     copy(P.edges.begin()+ai, P.edges.begin()+bi, edges.begin());
alpar@797: 
alpar@797:     _first = P.graphNode(a);
alpar@797:     _last = P.graphNode(b);
alpar@797:   }
alpar@797: 
alpar@797:   ///@}
alpar@797: 
alpar@797: } // namespace hugo
alpar@797: 
alpar@797: #endif // HUGO_PATH_H