RhodeCode

/* -*- mode: C++; indent-tabs-mode: nil; -*-

 *

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

 *

 * Copyright (C) 2003-2008

 * 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_CORE_H

#define LEMON_CORE_H

#include <vector>

#include <algorithm>

#include <lemon/bits/enable_if.h>

#include <lemon/bits/traits.h>

///\file

///\brief LEMON core utilities.

///

///This header file contains core utilities for LEMON.

///It is automatically included by all graph types, therefore it usually

///do not have to be included directly.

namespace lemon {

  /// \brief Dummy type to make it easier to create invalid iterators.

  ///

  /// Dummy type to make it easier to create invalid iterators.

  /// See \ref INVALID for the usage.

  struct Invalid {

  public:

    bool operator==(Invalid) { return true;  }

    bool operator!=(Invalid) { return false; }

    bool operator< (Invalid) { return false; }

  };

  /// \brief Invalid iterators.

  ///

  /// \ref Invalid is a global type that converts to each iterator

  /// in such a way that the value of the target iterator will be invalid.

#ifdef LEMON_ONLY_TEMPLATES

  const Invalid INVALID = Invalid();

#else

  extern const Invalid INVALID;

#endif

  /// \addtogroup gutils

  /// @{

  ///Create convenience typedefs for the digraph types and iterators

  ///This \c \#define creates convenient type definitions for the following

  ///types of \c Digraph: \c Node,  \c NodeIt, \c Arc, \c ArcIt, \c InArcIt,

  ///\c OutArcIt, \c BoolNodeMap, \c IntNodeMap, \c DoubleNodeMap,

  ///\c BoolArcMap, \c IntArcMap, \c DoubleArcMap.

  ///

  ///\note If the graph type is a dependent type, ie. the graph type depend

  ///on a template parameter, then use \c TEMPLATE_DIGRAPH_TYPEDEFS()

  ///macro.

#define DIGRAPH_TYPEDEFS(Digraph)                                       \

  typedef Digraph::Node Node;                                           \

  typedef Digraph::NodeIt NodeIt;                                       \

  typedef Digraph::Arc Arc;                                             \

  typedef Digraph::ArcIt ArcIt;                                         \

  typedef Digraph::InArcIt InArcIt;                                     \

  typedef Digraph::OutArcIt OutArcIt;                                   \

  typedef Digraph::NodeMap<bool> BoolNodeMap;                           \

  typedef Digraph::NodeMap<int> IntNodeMap;                             \

  typedef Digraph::NodeMap<double> DoubleNodeMap;                       \

  typedef Digraph::ArcMap<bool> BoolArcMap;                             \

  typedef Digraph::ArcMap<int> IntArcMap;                               \

  typedef Digraph::ArcMap<double> DoubleArcMap

  ///Create convenience typedefs for the digraph types and iterators

  ///\see DIGRAPH_TYPEDEFS

  ///

  ///\note Use this macro, if the graph type is a dependent type,

  ///ie. the graph type depend on a template parameter.

#define TEMPLATE_DIGRAPH_TYPEDEFS(Digraph)                              \

  typedef typename Digraph::Node Node;                                  \

  typedef typename Digraph::NodeIt NodeIt;                              \

  typedef typename Digraph::Arc Arc;                                    \

  typedef typename Digraph::ArcIt ArcIt;                                \

  typedef typename Digraph::InArcIt InArcIt;                            \

  typedef typename Digraph::OutArcIt OutArcIt;                          \

  typedef typename Digraph::template NodeMap<bool> BoolNodeMap;         \

  typedef typename Digraph::template NodeMap<int> IntNodeMap;           \

  typedef typename Digraph::template NodeMap<double> DoubleNodeMap;     \

  typedef typename Digraph::template ArcMap<bool> BoolArcMap;           \

  typedef typename Digraph::template ArcMap<int> IntArcMap;             \

  typedef typename Digraph::template ArcMap<double> DoubleArcMap

  ///Create convenience typedefs for the graph types and iterators

  ///This \c \#define creates the same convenient type definitions as defined

  ///by \ref DIGRAPH_TYPEDEFS(Graph) and six more, namely it creates

  ///\c Edge, \c EdgeIt, \c IncEdgeIt, \c BoolEdgeMap, \c IntEdgeMap,

  ///\c DoubleEdgeMap.

  ///

  ///\note If the graph type is a dependent type, ie. the graph type depend

  ///on a template parameter, then use \c TEMPLATE_GRAPH_TYPEDEFS()

  ///macro.

#define GRAPH_TYPEDEFS(Graph)                                           \

  DIGRAPH_TYPEDEFS(Graph);                                              \

  typedef Graph::Edge Edge;                                             \

  typedef Graph::EdgeIt EdgeIt;                                         \

  typedef Graph::IncEdgeIt IncEdgeIt;                                   \

  typedef Graph::EdgeMap<bool> BoolEdgeMap;                             \

  typedef Graph::EdgeMap<int> IntEdgeMap;                               \

  typedef Graph::EdgeMap<double> DoubleEdgeMap

  ///Create convenience typedefs for the graph types and iterators

  ///\see GRAPH_TYPEDEFS

  ///

  ///\note Use this macro, if the graph type is a dependent type,

  ///ie. the graph type depend on a template parameter.

#define TEMPLATE_GRAPH_TYPEDEFS(Graph)                                  \

  TEMPLATE_DIGRAPH_TYPEDEFS(Graph);                                     \

  typedef typename Graph::Edge Edge;                                    \

  typedef typename Graph::EdgeIt EdgeIt;                                \

  typedef typename Graph::IncEdgeIt IncEdgeIt;                          \

  typedef typename Graph::template EdgeMap<bool> BoolEdgeMap;           \

  typedef typename Graph::template EdgeMap<int> IntEdgeMap;             \

  typedef typename Graph::template EdgeMap<double> DoubleEdgeMap

  /// \brief Function to count the items in a graph.

  ///

  /// This function counts the items (nodes, arcs etc.) in a graph.

  /// The complexity of the function is linear because

  /// it iterates on all of the items.

  template <typename Graph, typename Item>

  inline int countItems(const Graph& g) {

    typedef typename ItemSetTraits<Graph, Item>::ItemIt ItemIt;

    int num = 0;

    for (ItemIt it(g); it != INVALID; ++it) {

      ++num;

    }

    return num;

  }

  // Node counting:

  namespace _core_bits {

    template <typename Graph, typename Enable = void>

    struct CountNodesSelector {

      static int count(const Graph &g) {

        return countItems<Graph, typename Graph::Node>(g);

      }

    };

    template <typename Graph>

    struct CountNodesSelector<

      Graph, typename

      enable_if<typename Graph::NodeNumTag, void>::type>

    {

      static int count(const Graph &g) {

        return g.nodeNum();

      }

    };

  }

  /// \brief Function to count the nodes in the graph.

  ///

  /// This function counts the nodes in the graph.

  /// The complexity of the function is <em>O</em>(<em>n</em>), but for some

  /// graph structures it is specialized to run in <em>O</em>(1).

  ///

  /// \note If the graph contains a \c nodeNum() member function and a

  /// \c NodeNumTag tag then this function calls directly the member

  /// function to query the cardinality of the node set.

  template <typename Graph>

  inline int countNodes(const Graph& g) {

    return _core_bits::CountNodesSelector<Graph>::count(g);

  }

  // Arc counting:

  namespace _core_bits {

    template <typename Graph, typename Enable = void>

    struct CountArcsSelector {

      static int count(const Graph &g) {

        return countItems<Graph, typename Graph::Arc>(g);

      }

    };

    template <typename Graph>

    struct CountArcsSelector<

      Graph,

      typename enable_if<typename Graph::ArcNumTag, void>::type>

    {

      static int count(const Graph &g) {

        return g.arcNum();

      }

    };

  }

  /// \brief Function to count the arcs in the graph.

  ///

  /// This function counts the arcs in the graph.

  /// The complexity of the function is <em>O</em>(<em>m</em>), but for some

  /// graph structures it is specialized to run in <em>O</em>(1).

  ///

  /// \note If the graph contains a \c arcNum() member function and a

/* -*- mode: C++; indent-tabs-mode: nil; -*-

 *

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

 *

 * Copyright (C) 2003-2008

 * 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_DFS_H

#define LEMON_DFS_H

///\ingroup search

///\file

///\brief DFS algorithm.

#include <lemon/list_graph.h>

#include <lemon/bits/path_dump.h>

#include <lemon/core.h>

#include <lemon/error.h>

#include <lemon/maps.h>

#include <lemon/path.h>

namespace lemon {

  ///Default traits class of Dfs class.

  ///Default traits class of Dfs class.

  ///\tparam GR Digraph type.

  template<class GR>

  struct DfsDefaultTraits

  {

    ///The type of the digraph the algorithm runs on.

    typedef GR Digraph;

    ///\brief The type of the map that stores the predecessor

    ///arcs of the %DFS paths.

    ///

    ///The type of the map that stores the predecessor

    ///arcs of the %DFS paths.

    ///It must meet the \ref concepts::WriteMap "WriteMap" concept.

    typedef typename Digraph::template NodeMap<typename Digraph::Arc> PredMap;

    ///Instantiates a PredMap.

    ///This function instantiates a PredMap.

    ///\param g is the digraph, to which we would like to define the

    ///PredMap.

    static PredMap *createPredMap(const Digraph &g)

    {

      return new PredMap(g);

    }

    ///The type of the map that indicates which nodes are processed.

    ///The type of the map that indicates which nodes are processed.

    ///It must meet the \ref concepts::WriteMap "WriteMap" concept.

    typedef NullMap<typename Digraph::Node,bool> ProcessedMap;

    ///Instantiates a ProcessedMap.

    ///This function instantiates a ProcessedMap.

    ///\param g is the digraph, to which

    ///we would like to define the ProcessedMap

#ifdef DOXYGEN

    static ProcessedMap *createProcessedMap(const Digraph &g)

#else

    static ProcessedMap *createProcessedMap(const Digraph &)

#endif

    {

      return new ProcessedMap();

    }

    ///The type of the map that indicates which nodes are reached.

    ///The type of the map that indicates which nodes are reached.

    ///It must meet the \ref concepts::ReadWriteMap "ReadWriteMap" concept.

    typedef typename Digraph::template NodeMap<bool> ReachedMap;

    ///Instantiates a ReachedMap.

    ///This function instantiates a ReachedMap.

    ///\param g is the digraph, to which

    ///we would like to define the ReachedMap.

    static ReachedMap *createReachedMap(const Digraph &g)

    {

      return new ReachedMap(g);

    }

    ///The type of the map that stores the distances of the nodes.

    ///The type of the map that stores the distances of the nodes.

    ///It must meet the \ref concepts::WriteMap "WriteMap" concept.

    typedef typename Digraph::template NodeMap<int> DistMap;

    ///Instantiates a DistMap.

    ///This function instantiates a DistMap.

    ///\param g is the digraph, to which we would like to define the

    ///DistMap.

    static DistMap *createDistMap(const Digraph &g)

    {

      return new DistMap(g);

    }

  };

  ///%DFS algorithm class.

  ///\ingroup search

  ///This class provides an efficient implementation of the %DFS algorithm.

  ///

  ///There is also a \ref dfs() "function-type interface" for the DFS

  ///algorithm, which is convenient in the simplier cases and it can be

  ///used easier.

  ///

  ///\tparam GR The type of the digraph the algorithm runs on.

  ///The default value is \ref ListDigraph. The value of GR is not used

  ///directly by \ref Dfs, it is only passed to \ref DfsDefaultTraits.

  ///\tparam TR Traits class to set various data types used by the algorithm.

  ///The default traits class is

  ///\ref DfsDefaultTraits "DfsDefaultTraits<GR>".

  ///See \ref DfsDefaultTraits for the documentation of

  ///a Dfs traits class.

#ifdef DOXYGEN

  template <typename GR,

            typename TR>

#else

  template <typename GR=ListDigraph,

            typename TR=DfsDefaultTraits<GR> >

#endif

  class Dfs {

  public:

    ///The type of the digraph the algorithm runs on.

    typedef typename TR::Digraph Digraph;

    ///\brief The type of the map that stores the predecessor arcs of the

    ///DFS paths.

    typedef typename TR::PredMap PredMap;

    ///The type of the map that stores the distances of the nodes.

    typedef typename TR::DistMap DistMap;

    ///The type of the map that indicates which nodes are reached.

    typedef typename TR::ReachedMap ReachedMap;

    ///The type of the map that indicates which nodes are processed.

    typedef typename TR::ProcessedMap ProcessedMap;

    ///The type of the paths.

    typedef PredMapPath<Digraph, PredMap> Path;

    ///The traits class.

    typedef TR Traits;

  private:

    typedef typename Digraph::Node Node;

    typedef typename Digraph::NodeIt NodeIt;

    typedef typename Digraph::Arc Arc;

    typedef typename Digraph::OutArcIt OutArcIt;

    //Pointer to the underlying digraph.

    const Digraph *G;

    //Pointer to the map of predecessor arcs.

    PredMap *_pred;

    //Indicates if _pred is locally allocated (true) or not.

    bool local_pred;

    //Pointer to the map of distances.

    DistMap *_dist;

    //Indicates if _dist is locally allocated (true) or not.

    bool local_dist;

    //Pointer to the map of reached status of the nodes.

    ReachedMap *_reached;

    //Indicates if _reached is locally allocated (true) or not.

    bool local_reached;

    //Pointer to the map of processed status of the nodes.

    ProcessedMap *_processed;

    //Indicates if _processed is locally allocated (true) or not.

    bool local_processed;

    std::vector<typename Digraph::OutArcIt> _stack;

    int _stack_head;

    //Creates the maps if necessary.

    void create_maps()

    {

      if(!_pred) {

        local_pred = true;

        _pred = Traits::createPredMap(*G);

      }

      if(!_dist) {

        local_dist = true;

        _dist = Traits::createDistMap(*G);

      }

      if(!_reached) {

        local_reached = true;

        _reached = Traits::createReachedMap(*G);

      }

      if(!_processed) {

        local_processed = true;

        _processed = Traits::createProcessedMap(*G);

      }

    }

  protected:

    Dfs() {}

  public:

    typedef Dfs Create;

    ///\name Named template parameters

    ///@{

    template <class T>

    struct SetPredMapTraits : public Traits {

      typedef T PredMap;

/* -*- mode: C++; indent-tabs-mode: nil; -*-

 *

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

 *

 * Copyright (C) 2003-2008

 * 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.

 *

 */

///\ingroup lemon_io

///\file

///\brief \ref lgf-format "LEMON Graph Format" reader.

#ifndef LEMON_LGF_READER_H

#define LEMON_LGF_READER_H

#include <iostream>

#include <fstream>

#include <sstream>

#include <set>

#include <map>

#include <lemon/core.h>

#include <lemon/lgf_writer.h>

#include <lemon/concept_check.h>

#include <lemon/concepts/maps.h>

namespace lemon {

  namespace _reader_bits {

    template <typename Value>

    struct DefaultConverter {

      Value operator()(const std::string& str) {

        std::istringstream is(str);

        Value value;

        if (!(is >> value)) {

          throw FormatError("Cannot read token");

        }

        char c;

        if (is >> std::ws >> c) {

          throw FormatError("Remaining characters in token");

        }

        return value;

      }

    };

    template <>

    struct DefaultConverter<std::string> {

      std::string operator()(const std::string& str) {

        return str;

      }

    };

    template <typename _Item>

    class MapStorageBase {

    public:

      typedef _Item Item;

    public:

      MapStorageBase() {}

      virtual ~MapStorageBase() {}

      virtual void set(const Item& item, const std::string& value) = 0;

    };

    template <typename _Item, typename _Map,

              typename _Converter = DefaultConverter<typename _Map::Value> >

    class MapStorage : public MapStorageBase<_Item> {

    public:

      typedef _Map Map;

      typedef _Converter Converter;

      typedef _Item Item;

    private:

      Map& _map;

      Converter _converter;

    public:

      MapStorage(Map& map, const Converter& converter = Converter())

        : _map(map), _converter(converter) {}

      virtual ~MapStorage() {}

      virtual void set(const Item& item ,const std::string& value) {

        _map.set(item, _converter(value));

      }

    };

    template <typename _Graph, bool _dir, typename _Map,

              typename _Converter = DefaultConverter<typename _Map::Value> >

    class GraphArcMapStorage : public MapStorageBase<typename _Graph::Edge> {

    public:

      typedef _Map Map;

      typedef _Converter Converter;

      typedef _Graph Graph;

      typedef typename Graph::Edge Item;

      static const bool dir = _dir;

    private:

      const Graph& _graph;

      Map& _map;

      Converter _converter;

    public:

      GraphArcMapStorage(const Graph& graph, Map& map,

                         const Converter& converter = Converter())

        : _graph(graph), _map(map), _converter(converter) {}

      virtual ~GraphArcMapStorage() {}

      virtual void set(const Item& item ,const std::string& value) {

        _map.set(_graph.direct(item, dir), _converter(value));

      }

    };

    class ValueStorageBase {

    public:

      ValueStorageBase() {}

      virtual ~ValueStorageBase() {}

      virtual void set(const std::string&) = 0;

    };

    template <typename _Value, typename _Converter = DefaultConverter<_Value> >

    class ValueStorage : public ValueStorageBase {

    public:

      typedef _Value Value;

      typedef _Converter Converter;

    private:

      Value& _value;

      Converter _converter;

    public:

      ValueStorage(Value& value, const Converter& converter = Converter())

        : _value(value), _converter(converter) {}

      virtual void set(const std::string& value) {

        _value = _converter(value);

      }

    };

    template <typename Value>

    struct MapLookUpConverter {

      const std::map<std::string, Value>& _map;

      MapLookUpConverter(const std::map<std::string, Value>& map)

        : _map(map) {}

      Value operator()(const std::string& str) {

        typename std::map<std::string, Value>::const_iterator it =

          _map.find(str);

        if (it == _map.end()) {

          std::ostringstream msg;

          msg << "Item not found: " << str;

          throw FormatError(msg.str());

        }

        return it->second;

      }

    };

    template <typename Graph>

    struct GraphArcLookUpConverter {

      const Graph& _graph;

      const std::map<std::string, typename Graph::Edge>& _map;

      GraphArcLookUpConverter(const Graph& graph,

                              const std::map<std::string,

                                             typename Graph::Edge>& map)

        : _graph(graph), _map(map) {}

      typename Graph::Arc operator()(const std::string& str) {

        if (str.empty() || (str[0] != '+' && str[0] != '-')) {

          throw FormatError("Item must start with '+' or '-'");

        }

        typename std::map<std::string, typename Graph::Edge>

          ::const_iterator it = _map.find(str.substr(1));

        if (it == _map.end()) {

          throw FormatError("Item not found");

        }

        return _graph.direct(it->second, str[0] == '+');

      }

    };

    inline bool isWhiteSpace(char c) {

      return c == ' ' || c == '\t' || c == '\v' ||

        c == '\n' || c == '\r' || c == '\f';

    }

    inline bool isOct(char c) {

      return '0' <= c && c <='7';

    }

    inline int valueOct(char c) {

      LEMON_ASSERT(isOct(c), "The character is not octal.");

      return c - '0';

    }

    inline bool isHex(char c) {

      return ('0' <= c && c <= '9') ||

        ('a' <= c && c <= 'z') ||

        ('A' <= c && c <= 'Z');

    }

    inline int valueHex(char c) {

      LEMON_ASSERT(isHex(c), "The character is not hexadecimal.");

      if ('0' <= c && c <= '9') return c - '0';

      if ('a' <= c && c <= 'z') return c - 'a' + 10;

      return c - 'A' + 10;

    }

/* -*- mode: C++; indent-tabs-mode: nil; -*-

 *

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

 *

 * Copyright (C) 2003-2008

 * 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.

 *

 */

///\ingroup lemon_io

///\file

///\brief \ref lgf-format "LEMON Graph Format" writer.

#ifndef LEMON_LGF_WRITER_H

#define LEMON_LGF_WRITER_H

#include <iostream>

#include <fstream>

#include <sstream>

#include <algorithm>

#include <vector>

#include <functional>

#include <lemon/core.h>

#include <lemon/maps.h>

#include <lemon/concept_check.h>

#include <lemon/concepts/maps.h>

namespace lemon {

  namespace _writer_bits {

    template <typename Value>

    struct DefaultConverter {

      std::string operator()(const Value& value) {

        std::ostringstream os;

        os << value;

        return os.str();

      }

    };

    template <typename T>

    bool operator<(const T&, const T&) {

      throw FormatError("Label map is not comparable");

    }

    template <typename _Map>

    class MapLess {

    public:

      typedef _Map Map;

      typedef typename Map::Key Item;

    private:

      const Map& _map;

    public:

      MapLess(const Map& map) : _map(map) {}

      bool operator()(const Item& left, const Item& right) {

        return _map[left] < _map[right];

      }

    };

    template <typename _Graph, bool _dir, typename _Map>

    class GraphArcMapLess {

    public:

      typedef _Map Map;

      typedef _Graph Graph;

      typedef typename Graph::Edge Item;

    private:

      const Graph& _graph;

      const Map& _map;

    public:

      GraphArcMapLess(const Graph& graph, const Map& map)

        : _graph(graph), _map(map) {}

      bool operator()(const Item& left, const Item& right) {

        return _map[_graph.direct(left, _dir)] <

          _map[_graph.direct(right, _dir)];

      }

    };

    template <typename _Item>

    class MapStorageBase {

    public:

      typedef _Item Item;

    public:

      MapStorageBase() {}

      virtual ~MapStorageBase() {}

      virtual std::string get(const Item& item) = 0;

      virtual void sort(std::vector<Item>&) = 0;

    };

    template <typename _Item, typename _Map,

              typename _Converter = DefaultConverter<typename _Map::Value> >

    class MapStorage : public MapStorageBase<_Item> {

    public:

      typedef _Map Map;

      typedef _Converter Converter;

      typedef _Item Item;

    private:

      const Map& _map;

      Converter _converter;

    public:

      MapStorage(const Map& map, const Converter& converter = Converter())

        : _map(map), _converter(converter) {}

      virtual ~MapStorage() {}

      virtual std::string get(const Item& item) {

        return _converter(_map[item]);

      }

      virtual void sort(std::vector<Item>& items) {

        MapLess<Map> less(_map);

        std::sort(items.begin(), items.end(), less);

      }

    };

    template <typename _Graph, bool _dir, typename _Map,

              typename _Converter = DefaultConverter<typename _Map::Value> >

    class GraphArcMapStorage : public MapStorageBase<typename _Graph::Edge> {

    public:

      typedef _Map Map;

      typedef _Converter Converter;

      typedef _Graph Graph;

      typedef typename Graph::Edge Item;

      static const bool dir = _dir;

    private:

      const Graph& _graph;

      const Map& _map;

      Converter _converter;

    public:

      GraphArcMapStorage(const Graph& graph, const Map& map,

                         const Converter& converter = Converter())

        : _graph(graph), _map(map), _converter(converter) {}

      virtual ~GraphArcMapStorage() {}

      virtual std::string get(const Item& item) {

        return _converter(_map[_graph.direct(item, dir)]);

      }

      virtual void sort(std::vector<Item>& items) {

        GraphArcMapLess<Graph, dir, Map> less(_graph, _map);

        std::sort(items.begin(), items.end(), less);

      }

    };

    class ValueStorageBase {

    public:

      ValueStorageBase() {}

      virtual ~ValueStorageBase() {}

      virtual std::string get() = 0;

    };

    template <typename _Value, typename _Converter = DefaultConverter<_Value> >

    class ValueStorage : public ValueStorageBase {

    public:

      typedef _Value Value;

      typedef _Converter Converter;

    private:

      const Value& _value;

      Converter _converter;

    public:

      ValueStorage(const Value& value, const Converter& converter = Converter())

        : _value(value), _converter(converter) {}

      virtual std::string get() {

        return _converter(_value);

      }

    };

    template <typename Value>

    struct MapLookUpConverter {

      const std::map<Value, std::string>& _map;

      MapLookUpConverter(const std::map<Value, std::string>& map)

        : _map(map) {}

      std::string operator()(const Value& str) {

        typename std::map<Value, std::string>::const_iterator it =

          _map.find(str);

        if (it == _map.end()) {

          throw FormatError("Item not found");

        }

        return it->second;

      }

    };

    template <typename Graph>

    struct GraphArcLookUpConverter {

      const Graph& _graph;

      const std::map<typename Graph::Edge, std::string>& _map;

      GraphArcLookUpConverter(const Graph& graph,

                              const std::map<typename Graph::Edge,

                                             std::string>& map)

        : _graph(graph), _map(map) {}

      std::string operator()(const typename Graph::Arc& val) {

        typename std::map<typename Graph::Edge, std::string>

          ::const_iterator it = _map.find(val);

        if (it == _map.end()) {

          throw FormatError("Item not found");

        }

        return (_graph.direction(val) ? '+' : '-') + it->second;