diff -r d8475431bbbb -r 8e85e6bbefdf lemon/bits/undir_graph_extender.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/lemon/bits/undir_graph_extender.h	Mon May 23 04:48:14 2005 +0000
@@ -0,0 +1,278 @@
+/* -*- C++ -*-
+ *
+ * lemon/undir_graph_extender.h - Part of LEMON, a generic C++
+ * optimization library
+ *
+ * Copyright (C) 2005 Egervary Jeno Kombinatorikus Optimalizalasi
+ * Kutatocsoport (Egervary Research Group on Combinatorial Optimization,
+ * EGRES).
+ *
+ * Permission to use, modify and distribute this software is granted
+ * provided that this copyright notice appears in all copies. For
+ * precise terms see the accompanying LICENSE file.
+ *
+ * This software is provided "AS IS" with no warranty of any kind,
+ * express or implied, and with no claim as to its suitability for any
+ * purpose.
+ *
+ */
+
+#ifndef LEMON_UNDIR_GRAPH_EXTENDER_H
+#define LEMON_UNDIR_GRAPH_EXTENDER_H
+
+#include <lemon/invalid.h>
+
+namespace lemon {
+
+  template <typename _Base>
+  class UndirGraphExtender : public _Base {
+    typedef _Base Parent;
+    typedef UndirGraphExtender Graph;
+
+  public:
+
+    typedef typename Parent::Edge UndirEdge;
+    typedef typename Parent::Node Node;
+
+    class Edge : public UndirEdge {
+      friend class UndirGraphExtender;
+
+    protected:
+      // FIXME: Marci use opposite logic in his graph adaptors. It would
+      // be reasonable to syncronize...
+      bool forward;
+
+    public:
+      Edge() {}
+
+      /// \brief Directed edge from undirected edge and a direction.
+      ///
+      /// This constructor is not a part of the concept interface of
+      /// undirected graph, so please avoid using it if possible!
+      Edge(const UndirEdge &ue, bool _forward) :
+        UndirEdge(ue), forward(_forward) {}
+
+      /// \brief Directed edge from undirected edge and a source node.
+      ///
+      /// Constructs a directed edge from undirected edge and a source node.
+      ///
+      /// \note You have to specify the graph for this constructor.
+      Edge(const Graph &g, const UndirEdge &ue, const Node &n) :
+	UndirEdge(ue) { forward = (g.source(ue) == n); }
+
+      /// Invalid edge constructor
+      Edge(Invalid i) : UndirEdge(i), forward(true) {}
+
+      bool operator==(const Edge &that) const {
+	return forward==that.forward && UndirEdge(*this)==UndirEdge(that);
+      }
+      bool operator!=(const Edge &that) const {
+	return forward!=that.forward || UndirEdge(*this)!=UndirEdge(that);
+      }
+      bool operator<(const Edge &that) const {
+	return forward<that.forward ||
+	  (!(that.forward<forward) && UndirEdge(*this)<UndirEdge(that));
+      }
+    };
+
+
+    /// \brief Edge of opposite direction.
+    ///
+    /// Returns the Edge of opposite direction.
+    Edge opposite(const Edge &e) const {
+      return Edge(e,!e.forward);
+    }
+
+  protected:
+
+    template <typename E>
+    Node _dirSource(const E &e) const {
+      return e.forward ? Parent::source(e) : Parent::target(e);
+    }
+
+    template <typename E>
+    Node _dirTarget(const E &e) const {
+      return e.forward ? Parent::target(e) : Parent::source(e);
+    }
+
+  public:
+    /// \todo Shouldn't the "source" of an undirected edge be called "aNode"
+    /// or something???
+    using Parent::source;
+
+    /// Source of the given Edge.
+    Node source(const Edge &e) const {
+      return _dirSource(e);
+    }
+
+    /// \todo Shouldn't the "target" of an undirected edge be called "bNode"
+    /// or something???
+    using Parent::target;
+
+    /// Target of the given Edge.
+    Node target(const Edge &e) const {
+      return _dirTarget(e);
+    }
+
+    /// Returns whether the given directed edge is same orientation as the
+    /// corresponding undirected edge.
+    ///
+    /// \todo reference to the corresponding point of the undirected graph
+    /// concept. "What does the direction of an undirected edge mean?"
+    bool forward(const Edge &e) const { return e.forward; }
+
+    Node oppositeNode(const Node &n, const UndirEdge &e) const {
+      if( n == Parent::source(e))
+	return Parent::target(e);
+      else if( n == Parent::target(e))
+	return Parent::source(e);
+      else
+	return INVALID;
+    }
+
+    /// Directed edge from an undirected edge and a source node.
+    ///
+    /// Returns a (directed) Edge corresponding to the specified UndirEdge
+    /// and source Node.
+    ///
+    ///\todo Do we need this?
+    ///
+    ///\todo Better name...
+    Edge edgeWithSource(const UndirEdge &ue, const Node &s) const {
+      return Edge(*this, ue, s);
+    }
+
+    using Parent::first;
+    void first(Edge &e) const {
+      Parent::first(e);
+      e.forward=true;
+    }
+
+    using Parent::next;
+    void next(Edge &e) const {
+      if( e.forward ) {
+	e.forward = false;
+      }
+      else {
+	Parent::next(e);
+	e.forward = true;
+      }
+    }
+
+    
+  protected:
+
+    template <typename E>
+    void _dirFirstOut(E &e, const Node &n) const {
+      Parent::firstIn(e,n);
+      if( UndirEdge(e) != INVALID ) {
+	e.forward = false;
+      }
+      else {
+	Parent::firstOut(e,n);
+	e.forward = true;
+      }
+    }
+    template <typename E>
+    void _dirFirstIn(E &e, const Node &n) const {
+      Parent::firstOut(e,n);
+      if( UndirEdge(e) != INVALID ) {
+	e.forward = false;
+      }
+      else {
+	Parent::firstIn(e,n);
+	e.forward = true;
+      }
+    }
+
+    template <typename E>
+    void _dirNextOut(E &e) const {
+      if( ! e.forward ) {
+	Node n = Parent::target(e);
+	Parent::nextIn(e);
+	if( UndirEdge(e) == INVALID ) {
+	  Parent::firstOut(e, n);
+	  e.forward = true;
+	}
+      }
+      else {
+	Parent::nextOut(e);
+      }
+    }
+    template <typename E>
+    void _dirNextIn(E &e) const {
+      if( ! e.forward ) {
+	Node n = Parent::source(e);
+	Parent::nextOut(e);
+	if( UndirEdge(e) == INVALID ) {
+	  Parent::firstIn(e, n);
+	  e.forward = true;
+	}
+      }
+      else {
+	Parent::nextIn(e);
+      }
+    }
+
+  public:
+
+    void firstOut(Edge &e, const Node &n) const {
+      _dirFirstOut(e, n);
+    }
+    void firstIn(Edge &e, const Node &n) const {
+      _dirFirstIn(e, n);
+    }
+
+    void nextOut(Edge &e) const {
+      _dirNextOut(e);
+    }
+    void nextIn(Edge &e) const {
+      _dirNextIn(e);
+    }
+
+    // Miscellaneous stuff:
+
+    /// \todo these methods (id, maxEdgeId) should be moved into separate
+    /// Extender
+
+    // using Parent::id;
+    // Using "using" is not a good idea, cause it could be that there is
+    // no "id" in Parent...
+
+    int id(const Node &n) const {
+      return Parent::id(n);
+    }
+
+    int id(const UndirEdge &e) const {
+      return Parent::id(e);
+    }
+
+    int id(const Edge &e) const {
+      return 2 * Parent::id(e) + int(e.forward);
+    }
+
+
+    int maxId(Node) const {
+      return Parent::maxId(Node());
+    }
+
+    int maxId(Edge) const {
+      return 2 * Parent::maxId(typename Parent::Edge()) + 1;
+    }
+    int maxId(UndirEdge) const {
+      return Parent::maxId(typename Parent::Edge());
+    }
+
+
+    int edgeNum() const {
+      return 2 * Parent::edgeNum();
+    }
+    int undirEdgeNum() const {
+      return Parent::edgeNum();
+    }
+
+  };
+
+}
+
+#endif // LEMON_UNDIR_GRAPH_EXTENDER_H