klao@962: /* -*- C++ -*-
klao@962:  *
klao@962:  * src/lemon/undir_graph_extender.h - Part of LEMON, a generic C++
klao@962:  * optimization library
klao@962:  *
klao@962:  * Copyright (C) 2004 Egervary Jeno Kombinatorikus Optimalizalasi
klao@962:  * Kutatocsoport (Egervary Combinatorial Optimization Research Group,
klao@962:  * EGRES).
klao@962:  *
klao@962:  * Permission to use, modify and distribute this software is granted
klao@962:  * provided that this copyright notice appears in all copies. For
klao@962:  * precise terms see the accompanying LICENSE file.
klao@962:  *
klao@962:  * This software is provided "AS IS" with no warranty of any kind,
klao@962:  * express or implied, and with no claim as to its suitability for any
klao@962:  * purpose.
klao@962:  *
klao@962:  */
klao@962: 
klao@962: #ifndef LEMON_UNDIR_GRAPH_EXTENDER_H
klao@962: #define LEMON_UNDIR_GRAPH_EXTENDER_H
klao@962: 
klao@962: #include <lemon/invalid.h>
klao@962: 
klao@962: namespace lemon {
klao@962: 
klao@962:   template <typename _Base>
klao@962:   class UndirGraphExtender : public _Base {
klao@962:     typedef _Base Parent;
klao@962:     typedef UndirGraphExtender Graph;
klao@962: 
klao@962:   public:
klao@962: 
klao@962:     typedef typename Parent::Edge UndirEdge;
klao@962:     typedef typename Parent::Node Node;
klao@962: 
klao@962:     class Edge : public UndirEdge {
klao@978:       friend class UndirGraphExtender;
klao@962: 
klao@962:     protected:
klao@962:       // FIXME: Marci use opposite logic in his graph wrappers. It would
klao@962:       // be reasonable to syncronize...
klao@962:       bool forward;
klao@962: 
klao@962:     public:
klao@962:       Edge() {}
klao@962:       /// Construct a direct edge from undirect edge and a direction.
klao@962:       Edge(const UndirEdge &ue, bool _forward) :
klao@962: 	UndirEdge(ue), forward(_forward) {}
klao@962:       /// Invalid edge constructor
klao@962:       Edge(Invalid i) : UndirEdge(i), forward(false) {}
klao@962: 
klao@962:       bool operator==(const Edge &that) const {
klao@962: 	return forward==that.forward && UndirEdge(*this)==UndirEdge(that);
klao@962:       }
klao@962:       bool operator!=(const Edge &that) const {
klao@962: 	return forward!=that.forward || UndirEdge(*this)!=UndirEdge(that);
klao@962:       }
klao@962:       bool operator<(const Edge &that) const {
klao@962: 	return forward<that.forward ||
klao@962: 	  (!(that.forward<forward) && UndirEdge(*this)<UndirEdge(that));
klao@962:       }
klao@962:     };
klao@962: 
klao@962: 
klao@962:     /// \brief Returns the Edge of opposite direction.
klao@962:     ///
klao@962:     /// \bug Is this a good name for this? Or "reverse" is better?
klao@962:     Edge opposite(const Edge &e) const {
klao@962:       return Edge(e,!e.forward);
klao@962:     }
klao@962: 
alpar@986:     /// Source of the given Edge.
alpar@986:     Node source(const Edge &e) const {
alpar@986:       return e.forward ? Parent::source(e) : Parent::target(e);
klao@962:     }
klao@962: 
alpar@986:     /// \todo Shouldn't the "source" of an undirected edge be called "aNode"
klao@962:     /// or something???
alpar@986:     using Parent::source;
klao@962: 
alpar@986:     /// Target of the given Edge.
alpar@986:     Node target(const Edge &e) const {
alpar@986:       return e.forward ? Parent::target(e) : Parent::source(e);
klao@962:     }
klao@962: 
alpar@986:     /// \todo Shouldn't the "target" of an undirected edge be called "bNode"
klao@962:     /// or something???
alpar@986:     using Parent::target;
klao@962: 
klao@962:     /// Returns whether the given directed edge is same orientation as the
klao@962:     /// corresponding undirected edge.
klao@962:     ///
klao@962:     /// \todo reference to the corresponding point of the undirected graph
klao@962:     /// concept. "What does the direction of an undirected edge mean?"
klao@962:     bool forward(const Edge &e) const { return e.forward; }
klao@962: 
klao@962:     Node oppsiteNode(const Node &n, const Edge &e) const {
alpar@986:       if( n == Parent::source(e))
alpar@986: 	return Parent::target(e);
alpar@986:       else if( n == Parent::target(e))
alpar@986: 	return Parent::source(e);
klao@962:       else
klao@962: 	return INVALID;
klao@962:     }
klao@962: 
klao@962: 
klao@962:     using Parent::first;
klao@962:     void first(Edge &e) const {
klao@962:       Parent::first(e);
klao@962:       e.forward=true;
klao@962:     }
klao@962: 
klao@962:     using Parent::next;
klao@962:     void next(Edge &e) const {
klao@962:       if( e.forward ) {
klao@962: 	e.forward = false;
klao@962:       }
klao@962:       else {
klao@962: 	Parent::next(e);
klao@962: 	e.forward = true;
klao@962:       }
klao@962:     }
klao@962: 
klao@962:     void firstOut(Edge &e, const Node &n) const {
klao@962:       Parent::firstOut(e,n);
klao@962:       if( UndirEdge(e) != INVALID ) {
klao@962: 	e.forward = true;
klao@962:       }
klao@962:       else {
klao@962: 	Parent::firstIn(e,n);
klao@962: 	e.forward = false;
klao@962:       }
klao@962:     }
klao@962:     void firstIn(Edge &e, const Node &n) const {
klao@962:       Parent::firstIn(e,n);
klao@962:       if( UndirEdge(e) != INVALID ) {
klao@962: 	e.forward = true;
klao@962:       }
klao@962:       else {
klao@962: 	Parent::firstOut(e,n);
klao@962: 	e.forward = false;
klao@962:       }
klao@962:     }
klao@962: 
klao@962:     void nextOut(Edge &e) const {
klao@962:       if( e.forward ) {
klao@962: 	Parent::nextOut(e);
klao@962: 	if( UndirEdge(e) == INVALID ) {
alpar@986: 	  Parent::firstIn(e, Parent::source(e));
klao@962: 	  e.forward = false;
klao@962: 	}
klao@962:       }
klao@962:       else {
klao@962: 	Parent::nextIn(e);
klao@962:       }
klao@962:     }
klao@962:     void nextIn(Edge &e) const {
klao@962:       if( e.forward ) {
klao@962: 	Parent::nextIn(e);
klao@962: 	if( UndirEdge(e) == INVALID ) {
alpar@986: 	  Parent::firstOut(e, Parent::target(e));
klao@962: 	  e.forward = false;
klao@962: 	}
klao@962:       }
klao@962:       else {
klao@962: 	Parent::nextOut(e);
klao@962:       }
klao@962:     }
klao@962: 
klao@962:     // Miscellaneous stuff:
klao@962: 
klao@962:     /// \todo these methods (id, maxEdgeId) should be moved into separate
klao@962:     /// Extender
klao@962: 
klao@962:     using Parent::id;
klao@962: 
klao@962:     int id(const Edge &e) const {
deba@981:       return 2 * Parent::id(e) + int(e.forward);
klao@962:     }
klao@962: 
deba@981:     int maxId(Edge = INVALID) const {
deba@981:       return 2 * Parent::maxId(typename Parent::Edge()) + 1;
klao@962:     }
deba@981:     int maxId(UndirEdge = INVALID) const {
deba@981:       return Parent::maxId(typename Parent::Edge());
klao@962:     }
klao@962: 
klao@962:   };
klao@962: 
klao@962: }
klao@962: 
klao@962: #endif // LEMON_UNDIR_GRAPH_EXTENDER_H