diff -r 5bc1c83257f8 -r b72b36a25170 src/work/klao/path.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/work/klao/path.h	Sun Mar 21 16:16:08 2004 +0000
@@ -0,0 +1,383 @@
+// -*- c++ -*- //
+
+/**
+ *
+ * Class for representing paths in graphs.
+ *
+ */
+
+#ifndef HUGO_PATH_H
+#define HUGO_PATH_H
+
+#include <deque>
+
+#include <invalid.h>
+
+namespace hugo {
+
+  /* Ennek az allocatorosdinak sokkal jobban utana kene nezni a hasznalata
+     elott. Eleg bonyinak nez ki, ahogyan azokat az STL-ben hasznaljak. */
+
+  template<typename Graph>
+  class Path {
+
+  public:
+    typedef typename Graph::Edge GraphEdge;
+    typedef typename Graph::Node GraphNode;
+    class NodeIt;
+    class EdgeIt;
+
+  protected:
+    Graph& G;
+    // FIXME: ehelyett eleg lenne tarolni ket boolt: a ket szelso el
+    // iranyitasat:
+    GraphNode _first, _last;
+    typedef std::deque<GraphEdge> Container;
+    Container edges;
+
+  public:
+
+    Path(Graph &_G) : G(_G), _first(INVALID), _last(INVALID) {}
+
+    /// Subpath defined by two nodes
+    Path(Path const& P, NodeIt a, NodeIt b) { FIXME; }
+    /// Subpath defined by tow edges. Contains edges in [a,b)
+    Path(Path const& P, EdgeIt a, EdgeIt b) { FIXME; }
+    
+    size_t length() const { return edges.size(); }
+    GraphNode from() const { return _first; }
+    GraphNode to() const { return _last; }
+
+    NodeIt& first(NodeIt &n) const { return nth(n, 0); }
+    EdgeIt& first(EdgeIt &e) const { return nth(e, 0); }
+    template<typename It>
+    It first() const { 
+      It e;
+      first(e);
+      return e; 
+    }
+
+    NodeIt& nth(NodeIt &, size_t) const;
+    EdgeIt& nth(EdgeIt &, size_t) const;
+    template<typename It>
+    It nth(size_t n) const { 
+      It e;
+      nth(e, n);
+      return e; 
+    }
+
+    bool valid(const NodeIt &n) const { return n.idx <= length(); }
+    bool valid(const EdgeIt &e) const { return e.it < edges.end(); }
+
+    bool isForward(const EdgeIt &e) const { return e.forw; }
+
+    EdgeIt& next(EdgeIt &e) const;
+    NodeIt& next(NodeIt &n) const;
+    template <typename It>
+    It getNext(It it) const {
+      It tmp(it); return next(tmp);
+    }
+
+    // A path is constructed using the following four functions.
+    // They return false if the requested operation is inconsistent
+    // with the path constructed so far.
+    // If your path has only one edge you MUST set either "from" or "to"!
+    // So you probably SHOULD call it in any case to be safe (and check the
+    // returned value to check if your path is consistent with your idea).
+    bool pushFront(const GraphEdge &e);
+    bool pushBack(const GraphEdge &e);
+    bool setFrom(const GraphNode &n);
+    bool setTo(const GraphNode &n);
+
+    // WARNING: these two functions return the head/tail of an edge with
+    // respect to the direction of the path!
+    // So G.head(P.graphEdge(e)) == P.graphNode(P.head(e)) holds only if 
+    // P.forward(e) is true (or the edge is a loop)!
+    NodeIt head(const EdgeIt& e) const;
+    NodeIt tail(const EdgeIt& e) const;
+
+    // FIXME: ezeknek valami jobb nev kellene!!!
+    GraphEdge graphEdge(const EdgeIt& e) const;
+    GraphNode graphNode(const NodeIt& n) const;
+
+
+    /*** Iterator classes ***/
+    class EdgeIt {
+      friend class Path;
+
+      typename Container::const_iterator it;
+      bool forw;
+    public:
+      // FIXME: jarna neki ilyen is...
+      // EdgeIt(Invalid);
+
+      bool forward() const { return forw; }
+
+      bool operator==(const EdgeIt& e) const { return it==e.it; }
+      bool operator!=(const EdgeIt& e) const { return it!=e.it; }
+      bool operator<(const EdgeIt& e) const { return it<e.it; }
+    };
+
+    class NodeIt {
+      friend class Path;
+      friend class EdgeIt;
+
+      int idx;
+      bool tail;  // Is this node the tail of the edge with same idx?
+
+    public:
+      // FIXME: jarna neki ilyen is...
+      // NodeIt(Invalid);
+
+      bool operator==(const NodeIt& n) const { return idx==n.idx; }
+      bool operator!=(const NodeIt& n) const { return idx!=n.idx; }
+      bool operator<(const NodeIt& n) const { return idx<n.idx; }
+    };
+
+  private:
+    bool edgeIncident(const GraphEdge &e, const GraphNode &a,
+		      GraphNode &b);
+    bool connectTwoEdges(const GraphEdge &e, const GraphEdge &f);
+  };
+
+  template<typename Gr>
+  typename Path<Gr>::EdgeIt&
+  Path<Gr>::next(Path::EdgeIt &e) const {
+    if( e.it == edges.end() ) 
+      return e;
+
+    GraphNode common_node = ( e.forw ? G.head(*e.it) : G.tail(*e.it) );
+    ++e.it;
+
+    // Invalid edgeit is always forward :)
+    if( e.it == edges.end() ) {
+      e.forw = true;
+      return e;
+    }
+
+    e.forw = ( G.tail(*e.it) == common_node );
+    return e;
+  }
+
+  template<typename Gr>
+  typename Path<Gr>::NodeIt& Path<Gr>::next(NodeIt &n) const {
+    if( n.idx >= length() ) {
+      // FIXME: invalid
+      n.idx = length()+1;
+      return n;
+    }
+
+    
+    GraphNode next_node = ( n.tail ? G.head(edges[n.idx]) :
+			      G.tail(edges[n.idx]) );
+    ++n.idx;
+    if( n.idx < length() ) {
+      n.tail = ( next_node == G.tail(edges[n.idx]) );
+    }
+    else {
+      n.tail = true;
+    }
+
+    return n;
+  }
+
+  template<typename Gr>
+  bool Path<Gr>::edgeIncident(const GraphEdge &e, const GraphNode &a,
+			  GraphNode &b) {
+    if( G.tail(e) == a ) {
+      b=G.head(e);
+      return true;
+    }
+    if( G.head(e) == a ) {
+      b=G.tail(e);
+      return true;
+    }
+    return false;
+  }
+
+  template<typename Gr>
+  bool Path<Gr>::connectTwoEdges(const GraphEdge &e,
+			     const GraphEdge &f) {
+    if( edgeIncident(f, G.tail(e), _last) ) {
+      _first = G.head(e);
+      return true;
+    }
+    if( edgeIncident(f, G.head(e), _last) ) {
+      _first = G.tail(e);
+      return true;
+    }
+    return false;
+  }
+
+  template<typename Gr>
+  bool Path<Gr>::pushFront(const GraphEdge &e) {
+    if( G.valid(_first) ) {
+	if( edgeIncident(e, _first, _first) ) {
+	  edges.push_front(e);
+	  return true;
+	}
+	else
+	  return false;
+    }
+    else if( length() < 1 || connectTwoEdges(e, edges[0]) ) {
+      edges.push_front(e);
+      return true;
+    }
+    else
+      return false;
+  }
+
+  template<typename Gr>
+  bool Path<Gr>::pushBack(const GraphEdge &e) {
+    if( G.valid(_last) ) {
+	if( edgeIncident(e, _last, _last) ) {
+	  edges.push_back(e);
+	  return true;
+	}
+	else
+	  return false;
+    }
+    else if( length() < 1 || connectTwoEdges(edges[0], e) ) {
+      edges.push_back(e);
+      return true;
+    }
+    else
+      return false;
+  }
+
+
+  template<typename Gr>
+  bool Path<Gr>::setFrom(const GraphNode &n) {
+    if( G.valid(_first) ) {
+      return _first == n;
+    }
+    else {
+      if( length() > 0) {
+	if( edgeIncident(edges[0], n, _last) ) {
+	  _first = n;
+	  return true;
+	}
+	else return false;
+      }
+      else {
+	_first = _last = n;
+	return true;
+      }
+    }
+  }
+
+  template<typename Gr>
+  bool Path<Gr>::setTo(const GraphNode &n) {
+    if( G.valid(_last) ) {
+      return _last == n;
+    }
+    else {
+      if( length() > 0) {
+	if( edgeIncident(edges[0], n, _first) ) {
+	  _last = n;
+	  return true;
+	}
+	else return false;
+      }
+      else {
+	_first = _last = n;
+	return true;
+      }
+    }
+  }
+
+
+  template<typename Gr>
+  typename Path<Gr>::NodeIt
+  Path<Gr>::tail(const EdgeIt& e) const {
+    NodeIt n;
+
+    if( e.it == edges.end() ) {
+      // FIXME: invalid-> invalid
+      n.idx = length() + 1;
+      n.tail = true;
+      return n;
+    }
+
+    n.idx = e.it-edges.begin();
+    n.tail = e.forw;
+  }
+
+  template<typename Gr>
+  typename Path<Gr>::NodeIt
+  Path<Gr>::head(const EdgeIt& e) const {
+    if( e.it == edges.end()-1 ) {
+      return _last;
+    }
+
+    EdgeIt next_edge = e;
+    next(next_edge);
+    return tail(next_edge);
+  }
+      
+  template<typename Gr>
+  typename Path<Gr>::GraphEdge
+  Path<Gr>::graphEdge(const EdgeIt& e) const {
+    if( e.it != edges.end() ) {
+      return *e.it;
+    }
+    else {
+      return INVALID;
+    }
+  }
+  
+  template<typename Gr>
+  typename Path<Gr>::GraphNode
+  Path<Gr>::graphNode(const NodeIt& n) const {
+    if( n.idx < length() ) {
+      return n.tail ? G.tail(edges[n.idx]) : G.head(edges[n.idx]);
+    }
+    else if( n.idx == length() ) {
+      return _last;
+    }
+    else {
+      return INVALID;
+    }
+  }
+
+  template<typename Gr>
+  typename Path<Gr>::EdgeIt& Path<Gr>::nth(EdgeIt &e, size_t k) const {
+    if( k<0 || k>=length() ) {
+      // FIXME: invalid EdgeIt
+      e.it = edges.end();
+      e.forw = true;
+      return e;
+    }
+
+    e.it = edges.begin()+k;
+    if(k==0) {
+      e.forw = ( G.tail(*e.it) == _first );
+    }
+    else {
+      e.forw = ( G.tail(*e.it) == G.tail(edges[k-1]) ||
+		 G.tail(*e.it) == G.head(edges[k-1]) );
+    }
+    return e;
+  }
+    
+  template<typename Gr>
+  typename Path<Gr>::NodeIt& Path<Gr>::nth(NodeIt &n, size_t k) const {
+    if( k<0 || k>length() ) {
+      // FIXME: invalid NodeIt
+      n.idx = length()+1;
+      n.tail = true;
+      return n;
+    }
+    if( k==length() ) {
+      n.idx = length();
+      n.tail = true;
+      return n;
+    }
+    n = tail(nth<EdgeIt>(k));
+    return n;
+  }
+
+
+} // namespace hugo
+
+#endif // HUGO_PATH_H