/* -*- C++ -*-

  *

  * This file is a part of LEMON, a generic C++ optimization library

  *

  * Copyright (C) 2003-2006

  * 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_BITS_PRED_MAP_PATH_H

 #define LEMON_BITS_PRED_MAP_PATH_H

 namespace lemon {

   template <typename _Graph, typename _PredMap>

   class PredMapPath {

   public:

     typedef True RevPathTag;

     typedef _Graph Graph;

     typedef typename Graph::Edge Edge;

     typedef _PredMap PredMap;

     PredMapPath(const Graph& _graph, const PredMap& _predMap,

                 typename Graph::Node _target)

       : graph(_graph), predMap(_predMap), target(_target) {}

     int length() const {

       int len = 0;

       typename Graph::Node node = target;

       typename Graph::Edge edge;

       while ((edge = predMap[node]) != INVALID) {

         node = graph.source(edge);

         ++len;

       }

       return len;

     }

     bool empty() const {

       return predMap[target] != INVALID;

     }

     class RevIt {

     public:

       RevIt() {}

       RevIt(Invalid) : path(0), current(INVALID) {}

       RevIt(const PredMapPath& _path) 

         : path(&_path), current(_path.target) {}

       operator const typename Graph::Edge() const {

         return path->predMap[current];

       }

       RevIt& operator++() {

         current = path->graph.source(path->predMap[current]);

         if (path->predMap[current] == INVALID) current = INVALID;

         return *this;

       }

       bool operator==(const RevIt& e) const { 

         return current == e.current; 

       }

       bool operator!=(const RevIt& e) const {

         return current != e.current; 

       }

       bool operator<(const RevIt& e) const { 

         return current < e.current; 

       }

     private:

       const PredMapPath* path;

       typename Graph::Node current;

     };

   private:

     const Graph& graph;

     const PredMap& predMap;

     typename Graph::Node target;

   };

   template <typename _Graph, typename _PredMatrixMap>

   class PredMatrixMapPath {

   public:

     typedef True RevPathTag;

     typedef _Graph Graph;

     typedef typename Graph::Edge Edge;

     typedef _PredMatrixMap PredMatrixMap;

     PredMatrixMapPath(const Graph& _graph, 

                       const PredMatrixMap& _predMatrixMap,

                       typename Graph::Node _source, 

                       typename Graph::Node _target)

       : graph(_graph), predMatrixMap(_predMatrixMap), 

         source(_source), target(_target) {}

     int length() const {

       int len = 0;

       typename Graph::Node node = target;

       typename Graph::Edge edge;

       while ((edge = predMatrixMap(source, node)) != INVALID) {

         node = graph.source(edge);

         ++len;

       }

       return len;

     }

     bool empty() const {

       return source != target;

     }

     class RevIt {

     public:

       RevIt() {}

       RevIt(Invalid) : path(0), current(INVALID) {}

       RevIt(const PredMatrixMapPath& _path) 

         : path(&_path), current(_path.target) {}

       operator const typename Graph::Edge() const {

         return path->predMatrixMap(path->source, current);

       }

       RevIt& operator++() {

         current = 

           path->graph.source(path->predMatrixMap(path->source, current));

         if (path->predMatrixMap(path->source, current) == INVALID) 

           current = INVALID;

         return *this;

       }

       bool operator==(const RevIt& e) const { 

         return current == e.current; 

       }

       bool operator!=(const RevIt& e) const {

         return current != e.current; 

       }

       bool operator<(const RevIt& e) const { 

         return current < e.current; 

       }

     private:

       const PredMatrixMapPath* path;

       typename Graph::Node current;

     };

   private:

     const Graph& graph;

     const PredMatrixMap& predMatrixMap;

     typename Graph::Node source;

     typename Graph::Node target;

   };

 }

 #endif