Index: src/work/klao/path.h
===================================================================
--- src/work/klao/path.h	(revision 607)
+++ src/work/klao/path.h	(revision 619)
@@ -24,4 +24,5 @@
   //! \brief A structure for representing directed path in a graph.
   //!
+  //! A structure for representing directed path in a graph.
   //! \param Graph The graph type in which the path is.
   //! \param DM DebugMode, defaults to DefaultDebugMode.
@@ -55,12 +56,25 @@
     /// Subpath defined by two nodes.
     /// \warning It is an error if the two edges are not in order!
-    /// \todo Implement!
-    DirPath(const DirPath &P, const NodeIt &a, const NodeIt &b);
+    DirPath(const DirPath &P, const NodeIt &a, const NodeIt &b) {
+      if( DM::range_check && (!a.valid() || !b.valid) ) {
+	// FIXME: this check should be more elaborate...
+	fault("DirPath, subpath ctor: invalid bounding nodes");
+      }
+      gr = P.gr;
+      edges.insert(edges.end(), P.edges.begin()+a.idx, P.edges.begin()+b.idx);
+    }
+
     /// \brief Subpath constructor.
     ///
     /// Subpath defined by two edges. Contains edges in [a,b)
     /// \warning It is an error if the two edges are not in order!
-    /// \todo Implement!
-    DirPath(const DirPath &P, const EdgeIt &a, const EdgeIt &b);
+    DirPath(const DirPath &P, const EdgeIt &a, const EdgeIt &b) {
+      if( DM::range_check && (!a.valid() || !b.valid) ) {
+	// FIXME: this check should be more elaborate...
+	fault("DirPath, subpath ctor: invalid bounding nodes");
+      }
+      gr = P.gr;
+      edges.insert(edges.end(), P.edges.begin()+a.idx, P.edges.begin()+b.idx);
+    }
 
     /// Length of the path.
@@ -94,21 +108,27 @@
     It& first(It &i) const { return i=It(*this); }
 
-    /// \brief Initializes node or edge iterator to point to the node or edge
-    /// of a given index.
-    template<typename It>
-    It& nth(It &i, int n) const {
-      // FIXME: this test should be different for NodeIt and EdgeIt:
+    /// \brief Initializes node iterator to point to the node of a given index.
+    NodeIt& nth(NodeIt &i, int n) const {
       if( DM::range_check && (n<0 || n>int(length())) )
 	fault("DirPath::nth: index out of range");
-      return i=It(*this, n);
+      return i=NodeIt(*this, n);
+    }
+
+    /// \brief Initializes edge iterator to point to the edge of a given index.
+    EdgeIt& nth(EdgeIt &i, int n) const {
+      if( DM::range_check && (n<0 || n>=int(length())) )
+	fault("DirPath::nth: index out of range");
+      return i=EdgeIt(*this, n);
     }
 
     /// Checks validity of a node or edge iterator.
     template<typename It>
-    bool valid(const It &i) const { return i.valid(); }
+    static
+    bool valid(const It &i) { return i.valid(); }
 
     /// Steps the given node or edge iterator.
     template<typename It>
-    It& next(It &e) const {
+    static
+    It& next(It &e) {
       if( DM::range_check && !e.valid() )
 	fault("DirPath::next() on invalid iterator");
@@ -119,4 +139,6 @@
     /// given edge iterator.
     NodeIt head(const EdgeIt& e) const {
+      if( DM::range_check && !e.valid() )
+	fault("DirPath::head() on invalid iterator");
       return NodeIt(*this, e.idx+1);
     }
@@ -125,4 +147,6 @@
     /// given edge iterator.
     NodeIt tail(const EdgeIt& e) const {
+      if( DM::range_check && !e.valid() )
+	fault("DirPath::tail() on invalid iterator");
       return NodeIt(*this, e.idx);
     }
@@ -171,5 +195,5 @@
       bool valid() const { return idx!=-1; }
 
-      operator const GraphEdge& () const {
+      operator const GraphNode& () const {
 	if(idx >= p->length())
 	  return p->to();
@@ -198,5 +222,5 @@
      *
      * You can push new edges to the front and to the back of the path in
-     * arbitrary order the you can commit these changes to the graph.
+     * arbitrary order then you should commit these changes to the graph.
      *
      * Fundamentally, for most "Paths" (classes fulfilling the
@@ -216,22 +240,16 @@
       Builder(DirPath &_P) : P(_P) {}
 
-      ///Sets the first node of the path.
+      /// Sets the starting node of the path.
       
-      ///Sets the first node of the path. If the path is empty, this
-      ///function or setTo() have to be called before any call to \ref
-      ///pushFront() or \ref pushBack()
-      void setFrom(const GraphNode &) {}
-      
-      ///Sets the last node of the path.
-      
-      ///Sets the last node of the path. If the path is empty, this
-      ///function or setFrom() have to be called before any call of \ref
-      ///pushFront() or \ref pushBack()
-      void setTo(const GraphNode &) {}
-      
+      /// Sets the starting node of the path. Edge added to the path
+      /// afterwards have to be incident to this node.
+      /// It should be called iff the path is empty and before any call to
+      /// \ref pushFront() or \ref pushBack()
+      void setStart(const GraphNode &) {}
+
       ///Push a new edge to the front of the path
 
       ///Push a new edge to the front of the path.
-      ///\sa setTo
+      ///\sa setStart
       void pushFront(const GraphEdge& e) {
 	if( DM::consistensy_check && !empty() && P.gr->head(e)!=from() ) {
@@ -244,5 +262,5 @@
 
       ///Push a new edge to the back of the path.
-      ///\sa setFrom
+      ///\sa setStart
       void pushBack(const GraphEdge& e) {
 	if( DM::consistensy_check && !empty() && P.gr->tail(e)!=to() ) {
@@ -266,11 +284,317 @@
       }
 
-//       ///Desctuctor
-
-//       ///The desctuctor.
-//       ///It commit also commit the changes.
-//       ///\todo Is this what we want?
-//  Nope. Let's use commit() explicitly.
-//       ~Builder() { commit(); }
+      // FIXME: Hmm, pontosan hogy is kene ezt csinalni?
+      // Hogy kenyelmes egy ilyet hasznalni?
+      void reserve(size_t r) {
+	front.reserve(r);
+	back.reserve(r);
+      }
+
+    private:
+      bool empty() {
+	return front.empty() && back.empty() && P.empty();
+      }
+
+      GraphNode from() const {
+	if( ! front.empty() )
+	  return P.gr->tail(front[front.size()-1]);
+	else if( ! P.empty() )
+	  return P.gr->tail(P.edges[0]);
+	else if( ! back.empty() )
+	  return P.gr->tail(back[0]);
+	else
+	  return INVALID;
+      }
+      GraphNode to() const {
+	if( ! back.empty() )
+	  return P.gr->head(back[back.size()-1]);
+	else if( ! P.empty() )
+	  return P.gr->head(P.edges[P.length()-1]);
+	else if( ! front.empty() )
+	  return P.gr->head(front[0]);
+	else
+	  return INVALID;
+      }
+
+    };
+
+  };
+
+
+
+
+
+
+
+
+
+
+  /**********************************************************************/
+
+
+  //! \brief A structure for representing undirected path in a graph.
+  //!
+  //! A structure for representing undirected path in a graph. Ie. this is
+  //! a path in a \e directed graph but the edges should not be directed
+  //! forward.
+  //!
+  //! \param Graph The graph type in which the path is.
+  //! \param DM DebugMode, defaults to DefaultDebugMode.
+  //! 
+  //! In a sense, the path can be treated as a graph, for is has \c NodeIt
+  //! and \c EdgeIt with the same usage. These types converts to the \c Node
+  //! and \c Edge of the original graph.
+  //!
+  //! \todo Thoroughfully check all the range and consistency tests.
+  template<typename Graph, typename DM = DefaultDebugMode>
+  class UndirPath {
+  public:
+    typedef typename Graph::Edge GraphEdge;
+    typedef typename Graph::Node GraphNode;
+    class NodeIt;
+    class EdgeIt;
+
+  protected:
+    const Graph *gr;
+    typedef std::vector<GraphEdge> Container;
+    Container edges;
+
+  public:
+
+    /// \param _G The graph in which the path is.
+    ///
+    UndirPath(const Graph &_G) : gr(&_G) {}
+
+    /// \brief Subpath constructor.
+    ///
+    /// Subpath defined by two nodes.
+    /// \warning It is an error if the two edges are not in order!
+    UndirPath(const UndirPath &P, const NodeIt &a, const NodeIt &b) {
+      if( DM::range_check && (!a.valid() || !b.valid) ) {
+	// FIXME: this check should be more elaborate...
+	fault("UndirPath, subpath ctor: invalid bounding nodes");
+      }
+      gr = P.gr;
+      edges.insert(edges.end(), P.edges.begin()+a.idx, P.edges.begin()+b.idx);
+    }
+
+    /// \brief Subpath constructor.
+    ///
+    /// Subpath defined by two edges. Contains edges in [a,b)
+    /// \warning It is an error if the two edges are not in order!
+    UndirPath(const UndirPath &P, const EdgeIt &a, const EdgeIt &b) {
+      if( DM::range_check && (!a.valid() || !b.valid) ) {
+	// FIXME: this check should be more elaborate...
+	fault("UndirPath, subpath ctor: invalid bounding nodes");
+      }
+      gr = P.gr;
+      edges.insert(edges.end(), P.edges.begin()+a.idx, P.edges.begin()+b.idx);
+    }
+
+    /// Length of the path.
+    size_t length() const { return edges.size(); }
+    /// Returns whether the path is empty.
+    bool empty() const { return edges.empty(); }
+
+    /// Resets the path to an empty path.
+    void clear() { edges.clear(); }
+
+    /// \brief Starting point of the path.
+    ///
+    /// Starting point of the path.
+    /// Returns INVALID if the path is empty.
+    GraphNode from() const {
+      return empty() ? INVALID : gr->tail(edges[0]);
+    }
+    /// \brief End point of the path.
+    ///
+    /// End point of the path.
+    /// Returns INVALID if the path is empty.
+    GraphNode to() const {
+      return empty() ? INVALID : gr->head(edges[length()-1]);
+    }
+
+    /// \brief Initializes node or edge iterator to point to the first
+    /// node or edge.
+    ///
+    /// \sa nth
+    template<typename It>
+    It& first(It &i) const { return i=It(*this); }
+
+    /// \brief Initializes node iterator to point to the node of a given index.
+    NodeIt& nth(NodeIt &i, int n) const {
+      if( DM::range_check && (n<0 || n>int(length())) )
+	fault("UndirPath::nth: index out of range");
+      return i=NodeIt(*this, n);
+    }
+
+    /// \brief Initializes edge iterator to point to the edge of a given index.
+    EdgeIt& nth(EdgeIt &i, int n) const {
+      if( DM::range_check && (n<0 || n>=int(length())) )
+	fault("UndirPath::nth: index out of range");
+      return i=EdgeIt(*this, n);
+    }
+
+    /// Checks validity of a node or edge iterator.
+    template<typename It>
+    static
+    bool valid(const It &i) { return i.valid(); }
+
+    /// Steps the given node or edge iterator.
+    template<typename It>
+    static
+    It& next(It &e) {
+      if( DM::range_check && !e.valid() )
+	fault("UndirPath::next() on invalid iterator");
+      return ++e;
+    }
+
+    /// \brief Returns node iterator pointing to the head node of the
+    /// given edge iterator.
+    NodeIt head(const EdgeIt& e) const {
+      if( DM::range_check && !e.valid() )
+	fault("UndirPath::head() on invalid iterator");
+      return NodeIt(*this, e.idx+1);
+    }
+
+    /// \brief Returns node iterator pointing to the tail node of the
+    /// given edge iterator.
+    NodeIt tail(const EdgeIt& e) const {
+      if( DM::range_check && !e.valid() )
+	fault("UndirPath::tail() on invalid iterator");
+      return NodeIt(*this, e.idx);
+    }
+
+
+    /*** Iterator classes ***/
+    class EdgeIt {
+      friend class UndirPath;
+
+      int idx;
+      const UndirPath *p;
+    public:
+      EdgeIt() {}
+      EdgeIt(Invalid) : idx(-1), p(0) {}
+      EdgeIt(const UndirPath &_p, int _idx = 0) :
+	idx(_idx), p(&_p) { validate(); }
+
+      bool valid() const { return idx!=-1; }
+
+      operator GraphEdge () const {
+	return valid() ? p->edges[idx] : INVALID;
+      }
+      EdgeIt& operator++() { ++idx; validate(); return *this; }
+
+      bool operator==(const EdgeIt& e) const { return idx==e.idx; }
+      bool operator!=(const EdgeIt& e) const { return idx!=e.idx; }
+      bool operator<(const EdgeIt& e) const { return idx<e.idx; }
+
+    private:
+      // FIXME: comparison between signed and unsigned...
+      // Jo ez igy? Vagy esetleg legyen a length() int?
+      void validate() { if( size_t(idx) >= p->length() ) idx=-1; }
+    };
+
+    class NodeIt {
+      friend class UndirPath;
+
+      int idx;
+      const UndirPath *p;
+    public:
+      NodeIt() {}
+      NodeIt(Invalid) : idx(-1), p(0) {}
+      NodeIt(const UndirPath &_p, int _idx = 0) :
+	idx(_idx), p(&_p) { validate(); }
+
+      bool valid() const { return idx!=-1; }
+
+      operator const GraphNode& () const {
+	if(idx >= p->length())
+	  return p->to();
+	else if(idx >= 0)
+	  return p->gr->tail(p->edges[idx]);
+	else
+	  return INVALID;
+      }
+      NodeIt& operator++() { ++idx; validate(); return *this; }
+
+      bool operator==(const NodeIt& e) const { return idx==e.idx; }
+      bool operator!=(const NodeIt& e) const { return idx!=e.idx; }
+      bool operator<(const NodeIt& e) const { return idx<e.idx; }
+
+    private:
+      void validate() { if( size_t(idx) > p->length() ) idx=-1; }
+    };
+
+    friend class Builder;    
+
+    /**
+     * \brief Class to build paths
+     * 
+     * \ingroup datas
+     * This class is used to fill a path with edges.
+     *
+     * You can push new edges to the front and to the back of the path in
+     * arbitrary order then you should commit these changes to the graph.
+     *
+     * Fundamentally, for most "Paths" (classes fulfilling the
+     * PathConcept) while the builder is active (after the first modifying
+     * operation and until the commit()) the original Path is in a
+     * "transitional" state (operations ot it have undefined result). But
+     * in the case of UndirPath the original path is unchanged until the
+     * commit. However we don't recomend that you use this feature.
+     */
+    class Builder {
+      UndirPath &P;
+      Container front, back;
+
+    public:
+      ///\param _P the path you want to fill in.
+      ///
+      Builder(UndirPath &_P) : P(_P) {}
+
+      /// Sets the starting node of the path.
+      
+      /// Sets the starting node of the path. Edge added to the path
+      /// afterwards have to be incident to this node.
+      /// It should be called iff the path is empty and before any call to
+      /// \ref pushFront() or \ref pushBack()
+      void setStart(const GraphNode &) {}
+
+      ///Push a new edge to the front of the path
+
+      ///Push a new edge to the front of the path.
+      ///\sa setStart
+      void pushFront(const GraphEdge& e) {
+	if( DM::consistensy_check && !empty() && P.gr->head(e)!=from() ) {
+	  fault("UndirPath::Builder::pushFront: nonincident edge");
+	}
+	front.push_back(e);
+      }
+
+      ///Push a new edge to the back of the path
+
+      ///Push a new edge to the back of the path.
+      ///\sa setStart
+      void pushBack(const GraphEdge& e) {
+	if( DM::consistensy_check && !empty() && P.gr->tail(e)!=to() ) {
+	  fault("UndirPath::Builder::pushBack: nonincident edge");
+	}
+	back.push_back(e);
+      }
+
+      ///Commit the changes to the path.
+      void commit() {
+	if( !(front.empty() && back.empty()) ) {
+	  Container tmp;
+	  tmp.reserve(front.size()+back.size()+P.length());
+	  tmp.insert(tmp.end(), front.rbegin(), front.rend());
+	  tmp.insert(tmp.end(), P.edges.begin(), P.edges.end());
+	  tmp.insert(tmp.end(), back.begin(), back.end());
+	  P.edges.swap(tmp);
+	  front.clear();
+	  back.clear();
+	}
+      }
 
       // FIXME: Hmm, pontosan hogy is kene ezt csinalni?
