RhodeCode

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

 *

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

 *

 * Copyright (C) 2003-2009

 * 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_GRAPH_ADAPTOR_EXTENDER_H

#define LEMON_BITS_GRAPH_ADAPTOR_EXTENDER_H

#include <lemon/core.h>

#include <lemon/error.h>

namespace lemon {

  template <typename _Digraph>

  class DigraphAdaptorExtender : public _Digraph {

  public:

    typedef _Digraph Parent;

    typedef _Digraph Digraph;

    typedef DigraphAdaptorExtender Adaptor;

    // Base extensions

    typedef typename Parent::Node Node;

    typedef typename Parent::Arc Arc;

    int maxId(Node) const {

      return Parent::maxNodeId();

    }

    int maxId(Arc) const {

      return Parent::maxArcId();

    }

    Node fromId(int id, Node) const {

      return Parent::nodeFromId(id);

    }

    Arc fromId(int id, Arc) const {

      return Parent::arcFromId(id);

    }

    Node oppositeNode(const Node &n, const Arc &e) const {

      if (n == Parent::source(e))

        return Parent::target(e);

      else if(n==Parent::target(e))

        return Parent::source(e);

      else

        return INVALID;

    }

    class NodeIt : public Node {

      const Adaptor* _adaptor;

    public:

      NodeIt() {}

      NodeIt(Invalid i) : Node(i) { }

      explicit NodeIt(const Adaptor& adaptor) : _adaptor(&adaptor) {

        _adaptor->first(static_cast<Node&>(*this));

      }

      NodeIt(const Adaptor& adaptor, const Node& node)

        : Node(node), _adaptor(&adaptor) {}

      NodeIt& operator++() {

        _adaptor->next(*this);

        return *this;

      }

    };

    class ArcIt : public Arc {

      const Adaptor* _adaptor;

    public:

      ArcIt() { }

      ArcIt(Invalid i) : Arc(i) { }

      explicit ArcIt(const Adaptor& adaptor) : _adaptor(&adaptor) {

        _adaptor->first(static_cast<Arc&>(*this));

      }

      ArcIt(const Adaptor& adaptor, const Arc& e) :

        Arc(e), _adaptor(&adaptor) { }

      ArcIt& operator++() {

        _adaptor->next(*this);

        return *this;

      }

    };

    class OutArcIt : public Arc {

      const Adaptor* _adaptor;

    public:

      OutArcIt() { }

      OutArcIt(Invalid i) : Arc(i) { }

      OutArcIt(const Adaptor& adaptor, const Node& node)

        : _adaptor(&adaptor) {

        _adaptor->firstOut(*this, node);

      }

      OutArcIt(const Adaptor& adaptor, const Arc& arc)

        : Arc(arc), _adaptor(&adaptor) {}

      OutArcIt& operator++() {

        _adaptor->nextOut(*this);

        return *this;

      }

    };

    class InArcIt : public Arc {

      const Adaptor* _adaptor;

    public:

      InArcIt() { }

      InArcIt(Invalid i) : Arc(i) { }

      InArcIt(const Adaptor& adaptor, const Node& node)

        : _adaptor(&adaptor) {

        _adaptor->firstIn(*this, node);

      }

      InArcIt(const Adaptor& adaptor, const Arc& arc) :

        Arc(arc), _adaptor(&adaptor) {}

      InArcIt& operator++() {

        _adaptor->nextIn(*this);

        return *this;

      }

    };

    Node baseNode(const OutArcIt &e) const {

      return Parent::source(e);

    }

    Node runningNode(const OutArcIt &e) const {

      return Parent::target(e);

    }

    Node baseNode(const InArcIt &e) const {

      return Parent::target(e);

    }

    Node runningNode(const InArcIt &e) const {

      return Parent::source(e);

    }

  };

  template <typename _Graph>

  class GraphAdaptorExtender : public _Graph {

  public:

    typedef _Graph Parent;

    typedef _Graph Graph;

    typedef GraphAdaptorExtender Adaptor;

    typedef typename Parent::Node Node;

    typedef typename Parent::Arc Arc;

    typedef typename Parent::Edge Edge;

    // Graph extension

    int maxId(Node) const {

      return Parent::maxNodeId();

    }

    int maxId(Arc) const {

      return Parent::maxArcId();

    }

    int maxId(Edge) const {

      return Parent::maxEdgeId();

    }

    Node fromId(int id, Node) const {

      return Parent::nodeFromId(id);

    }

    Arc fromId(int id, Arc) const {

      return Parent::arcFromId(id);

    }

    Edge fromId(int id, Edge) const {

      return Parent::edgeFromId(id);

    }

    Node oppositeNode(const Node &n, const Edge &e) const {

      if( n == Parent::u(e))

        return Parent::v(e);

      else if( n == Parent::v(e))

        return Parent::u(e);

      else

        return INVALID;

    }

    Arc oppositeArc(const Arc &a) const {

      return Parent::direct(a, !Parent::direction(a));

    }

    using Parent::direct;

    Arc direct(const Edge &e, const Node &s) const {

      return Parent::direct(e, Parent::u(e) == s);

    }

    class NodeIt : public Node {

      const Adaptor* _adaptor;

    public:

      NodeIt() {}

      NodeIt(Invalid i) : Node(i) { }

      explicit NodeIt(const Adaptor& adaptor) : _adaptor(&adaptor) {

        _adaptor->first(static_cast<Node&>(*this));

      }

      NodeIt(const Adaptor& adaptor, const Node& node)

        : Node(node), _adaptor(&adaptor) {}

      NodeIt& operator++() {

        _adaptor->next(*this);

        return *this;

      }

    };

    class ArcIt : public Arc {

      const Adaptor* _adaptor;

    public:

      ArcIt() { }

      ArcIt(Invalid i) : Arc(i) { }

      explicit ArcIt(const Adaptor& adaptor) : _adaptor(&adaptor) {

        _adaptor->first(static_cast<Arc&>(*this));

      }

      ArcIt(const Adaptor& adaptor, const Arc& e) :

        Arc(e), _adaptor(&adaptor) { }

      ArcIt& operator++() {

        _adaptor->next(*this);

        return *this;

      }

    };

    class OutArcIt : public Arc {

      const Adaptor* _adaptor;

    public:

      OutArcIt() { }

      OutArcIt(Invalid i) : Arc(i) { }

      OutArcIt(const Adaptor& adaptor, const Node& node)

        : _adaptor(&adaptor) {

        _adaptor->firstOut(*this, node);

      }

      OutArcIt(const Adaptor& adaptor, const Arc& arc)

        : Arc(arc), _adaptor(&adaptor) {}

      OutArcIt& operator++() {

        _adaptor->nextOut(*this);

        return *this;

      }

    };

    class InArcIt : public Arc {

      const Adaptor* _adaptor;

    public:

      InArcIt() { }

      InArcIt(Invalid i) : Arc(i) { }

      InArcIt(const Adaptor& adaptor, const Node& node)

        : _adaptor(&adaptor) {

        _adaptor->firstIn(*this, node);

      }

      InArcIt(const Adaptor& adaptor, const Arc& arc) :

        Arc(arc), _adaptor(&adaptor) {}

      InArcIt& operator++() {

        _adaptor->nextIn(*this);

        return *this;

      }

    };

    class EdgeIt : public Parent::Edge {

      const Adaptor* _adaptor;

    public:

      EdgeIt() { }

      EdgeIt(Invalid i) : Edge(i) { }

      explicit EdgeIt(const Adaptor& adaptor) : _adaptor(&adaptor) {

        _adaptor->first(static_cast<Edge&>(*this));

      }

      EdgeIt(const Adaptor& adaptor, const Edge& e) :

        Edge(e), _adaptor(&adaptor) { }

      EdgeIt& operator++() {

        _adaptor->next(*this);

        return *this;

      }

    };

    class IncEdgeIt : public Edge {

      friend class GraphAdaptorExtender;

      const Adaptor* _adaptor;

      bool direction;

    public:

      IncEdgeIt() { }

      IncEdgeIt(Invalid i) : Edge(i), direction(false) { }

      IncEdgeIt(const Adaptor& adaptor, const Node &n) : _adaptor(&adaptor) {

        _adaptor->firstInc(static_cast<Edge&>(*this), direction, n);

      }

      IncEdgeIt(const Adaptor& adaptor, const Edge &e, const Node &n)

        : _adaptor(&adaptor), Edge(e) {

        direction = (_adaptor->u(e) == n);

      }

      IncEdgeIt& operator++() {

        _adaptor->nextInc(*this, direction);

        return *this;

      }

    };

    Node baseNode(const OutArcIt &a) const {

      return Parent::source(a);

    }

    Node runningNode(const OutArcIt &a) const {

      return Parent::target(a);

    }

    Node baseNode(const InArcIt &a) const {

      return Parent::target(a);

    }

    Node runningNode(const InArcIt &a) const {

      return Parent::source(a);

    }

    Node baseNode(const IncEdgeIt &e) const {

      return e.direction ? Parent::u(e) : Parent::v(e);

    }

    Node runningNode(const IncEdgeIt &e) const {

      return e.direction ? Parent::v(e) : Parent::u(e);

    }

  };

}

#endif

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

 *

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

 *

 * Copyright (C) 2003-2009

 * 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_MAP_EXTENDER_H

#define LEMON_BITS_MAP_EXTENDER_H

#include <iterator>

#include <lemon/bits/traits.h>

#include <lemon/concept_check.h>

#include <lemon/concepts/maps.h>

//\file

//\brief Extenders for iterable maps.

namespace lemon {

  // \ingroup graphbits

  //

  // \brief Extender for maps

  template <typename _Map>

  class MapExtender : public _Map {

  public:

    typedef _Map Parent;

    typedef MapExtender Map;

    typedef typename Parent::Graph Graph;

    typedef typename Parent::Key Item;

    typedef typename Parent::Key Key;

    typedef typename Parent::Value Value;

    class MapIt;

    class ConstMapIt;

    friend class MapIt;

    friend class ConstMapIt;

  public:

    MapExtender(const Graph& graph)

      : Parent(graph) {}

    MapExtender(const Graph& graph, const Value& value)

      : Parent(graph, value) {}

  private:

    MapExtender& operator=(const MapExtender& cmap) {

      return operator=<MapExtender>(cmap);

    }

    template <typename CMap>

    MapExtender& operator=(const CMap& cmap) {

      Parent::operator=(cmap);

      return *this;

    }

  public:

    class MapIt : public Item {

    public:

      typedef Item Parent;

      typedef typename Map::Value Value;

      MapIt() {}

      MapIt(Invalid i) : Parent(i) { }

      explicit MapIt(Map& _map) : map(_map) {

        map.notifier()->first(*this);

      }

      MapIt(const Map& _map, const Item& item)

        : Parent(item), map(_map) {}

      MapIt& operator++() {

        map.notifier()->next(*this);

        return *this;

      }

      typename MapTraits<Map>::ConstReturnValue operator*() const {

        return map[*this];

      }

      typename MapTraits<Map>::ReturnValue operator*() {

        return map[*this];

      }

      void set(const Value& value) {

        map.set(*this, value);

      }

    protected:

      Map& map;

    };

    class ConstMapIt : public Item {

    public:

      typedef Item Parent;

      typedef typename Map::Value Value;

      ConstMapIt() {}

      ConstMapIt(Invalid i) : Parent(i) { }

      explicit ConstMapIt(Map& _map) : map(_map) {

        map.notifier()->first(*this);

      }

      ConstMapIt(const Map& _map, const Item& item)

        : Parent(item), map(_map) {}

      ConstMapIt& operator++() {

        map.notifier()->next(*this);

        return *this;

      }

      typename MapTraits<Map>::ConstReturnValue operator*() const {

        return map[*this];

      }

    protected:

      const Map& map;

    };

    class ItemIt : public Item {

    public:

      typedef Item Parent;

      ItemIt() {}

      ItemIt(Invalid i) : Parent(i) { }

      explicit ItemIt(Map& _map) : map(_map) {

        map.notifier()->first(*this);

      }

      ItemIt(const Map& _map, const Item& item)

        : Parent(item), map(_map) {}

      ItemIt& operator++() {

        map.notifier()->next(*this);

        return *this;

      }

    protected:

      const Map& map;

    };

  };

  // \ingroup graphbits

  //

  // \brief Extender for maps which use a subset of the items.

  template <typename _Graph, typename _Map>

  class SubMapExtender : public _Map {

  public:

    typedef _Map Parent;

    typedef SubMapExtender Map;

    typedef _Graph Graph;

    typedef typename Parent::Key Item;

    typedef typename Parent::Key Key;

    typedef typename Parent::Value Value;

    class MapIt;

    class ConstMapIt;

    friend class MapIt;

    friend class ConstMapIt;

  public:

    SubMapExtender(const Graph& _graph)

      : Parent(_graph), graph(_graph) {}

    SubMapExtender(const Graph& _graph, const Value& _value)

      : Parent(_graph, _value), graph(_graph) {}

  private:

    SubMapExtender& operator=(const SubMapExtender& cmap) {

      return operator=<MapExtender>(cmap);

    }

    template <typename CMap>

    SubMapExtender& operator=(const CMap& cmap) {

      checkConcept<concepts::ReadMap<Key, Value>, CMap>();

      Item it;

      for (graph.first(it); it != INVALID; graph.next(it)) {

        Parent::set(it, cmap[it]);

      }

      return *this;

    }

  public:

    class MapIt : public Item {

    public:

      typedef Item Parent;

      typedef typename Map::Value Value;

      MapIt() {}

      MapIt(Invalid i) : Parent(i) { }

      explicit MapIt(Map& _map) : map(_map) {

        map.graph.first(*this);

      }

      MapIt(const Map& _map, const Item& item)

        : Parent(item), map(_map) {}

      MapIt& operator++() {

        map.graph.next(*this);

        return *this;

      }

      typename MapTraits<Map>::ConstReturnValue operator*() const {

        return map[*this];

      }

      typename MapTraits<Map>::ReturnValue operator*() {

        return map[*this];

      }

      void set(const Value& value) {

        map.set(*this, value);

      }

    protected:

      Map& map;

    };

    class ConstMapIt : public Item {

    public:

      typedef Item Parent;

      typedef typename Map::Value Value;

      ConstMapIt() {}

      ConstMapIt(Invalid i) : Parent(i) { }

      explicit ConstMapIt(Map& _map) : map(_map) {

        map.graph.first(*this);

      }

      ConstMapIt(const Map& _map, const Item& item)

        : Parent(item), map(_map) {}

      ConstMapIt& operator++() {

        map.graph.next(*this);

        return *this;

      }

      typename MapTraits<Map>::ConstReturnValue operator*() const {

        return map[*this];

      }

    protected:

      const Map& map;

    };

    class ItemIt : public Item {

    public:

      typedef Item Parent;

      ItemIt() {}

      ItemIt(Invalid i) : Parent(i) { }

      explicit ItemIt(Map& _map) : map(_map) {

        map.graph.first(*this);

      }

      ItemIt(const Map& _map, const Item& item)

        : Parent(item), map(_map) {}

      ItemIt& operator++() {

        map.graph.next(*this);

        return *this;

      }

    protected:

      const Map& map;

    };

  private:

    const Graph& graph;

  };

}

#endif

    ///

    /// Note that actual digraph implementation like @ref ListDigraph or

    /// @ref SmartDigraph may have several additional functionality.

    ///

    /// \sa concept

    class Digraph {

    private:

      ///Digraphs are \e not copy constructible. Use DigraphCopy() instead.

      ///Digraphs are \e not copy constructible. Use DigraphCopy() instead.

      ///

      Digraph(const Digraph &) {};

      ///\brief Assignment of \ref Digraph "Digraph"s to another ones are

      ///\e not allowed. Use DigraphCopy() instead.

      ///Assignment of \ref Digraph "Digraph"s to another ones are

      ///\e not allowed.  Use DigraphCopy() instead.

      void operator=(const Digraph &) {}

    public:

      ///\e

      /// Defalult constructor.

      /// Defalult constructor.

      ///

      Digraph() { }

      /// Class for identifying a node of the digraph

      /// This class identifies a node of the digraph. It also serves

      /// as a base class of the node iterators,

      /// thus they will convert to this type.

      class Node {

      public:

        /// Default constructor

        /// @warning The default constructor sets the iterator

        /// to an undefined value.

        Node() { }

        /// Copy constructor.

        /// Copy constructor.

        ///

        Node(const Node&) { }

        /// Invalid constructor \& conversion.

        /// This constructor initializes the iterator to be invalid.

        /// \sa Invalid for more details.

        Node(Invalid) { }

        /// Equality operator

        /// Two iterators are equal if and only if they point to the

        /// same object or both are invalid.

        bool operator==(Node) const { return true; }

        /// Inequality operator

        /// \sa operator==(Node n)

        ///

        bool operator!=(Node) const { return true; }

        /// Artificial ordering operator.

        /// To allow the use of digraph descriptors as key type in std::map or

        /// similar associative container we require this.

        ///

        /// \note This operator only have to define some strict ordering of

        /// the items; this order has nothing to do with the iteration

        /// ordering of the items.

        bool operator<(Node) const { return false; }

      };

      /// This iterator goes through each node.

      /// This iterator goes through each node.

      /// Its usage is quite simple, for example you can count the number

      /// of nodes in digraph \c g of type \c Digraph like this:

      ///\code

      /// int count=0;

      /// for (Digraph::NodeIt n(g); n!=INVALID; ++n) ++count;

      ///\endcode

      class NodeIt : public Node {

      public:

        /// Default constructor

        /// @warning The default constructor sets the iterator

        /// to an undefined value.

        NodeIt() { }

        /// Copy constructor.

        /// Copy constructor.

        ///

        NodeIt(const NodeIt& n) : Node(n) { }

        /// Invalid constructor \& conversion.

        /// Initialize the iterator to be invalid.

        /// \sa Invalid for more details.

        NodeIt(Invalid) { }

        /// Sets the iterator to the first node.

        /// Sets the iterator to the first node of \c g.

        ///

        NodeIt(const Digraph&) { }

        /// Node -> NodeIt conversion.

        /// Sets the iterator to the node of \c the digraph pointed by

        /// the trivial iterator.

        /// This feature necessitates that each time we

        /// iterate the arc-set, the iteration order is the same.

        NodeIt(const Digraph&, const Node&) { }

        /// Next node.

        /// Assign the iterator to the next node.

        ///

        NodeIt& operator++() { return *this; }

      };

      /// Class for identifying an arc of the digraph

      /// This class identifies an arc of the digraph. It also serves

      /// as a base class of the arc iterators,

      /// thus they will convert to this type.

      class Arc {

      public:

        /// Default constructor

        /// @warning The default constructor sets the iterator

        /// to an undefined value.

        Arc() { }

        /// Copy constructor.

        /// Copy constructor.

        ///

        Arc(const Arc&) { }

        /// Initialize the iterator to be invalid.

        /// Initialize the iterator to be invalid.

        ///

        Arc(Invalid) { }

        /// Equality operator

        /// Two iterators are equal if and only if they point to the

        /// same object or both are invalid.

        bool operator==(Arc) const { return true; }

        /// Inequality operator

        /// \sa operator==(Arc n)

        ///

        bool operator!=(Arc) const { return true; }

        /// Artificial ordering operator.

        /// To allow the use of digraph descriptors as key type in std::map or

        /// similar associative container we require this.

        ///

        /// \note This operator only have to define some strict ordering of

        /// the items; this order has nothing to do with the iteration

        /// ordering of the items.

        bool operator<(Arc) const { return false; }

      };

      /// This iterator goes trough the outgoing arcs of a node.

      /// This iterator goes trough the \e outgoing arcs of a certain node

      /// of a digraph.

      /// Its usage is quite simple, for example you can count the number

      /// of outgoing arcs of a node \c n

      /// in digraph \c g of type \c Digraph as follows.

      ///\code

      /// int count=0;

      /// for (Digraph::OutArcIt e(g, n); e!=INVALID; ++e) ++count;

      ///\endcode

      class OutArcIt : public Arc {

      public:

        /// Default constructor

        /// @warning The default constructor sets the iterator

        /// to an undefined value.

        OutArcIt() { }

        /// Copy constructor.

        /// Copy constructor.

        ///

        OutArcIt(const OutArcIt& e) : Arc(e) { }

        /// Initialize the iterator to be invalid.

        /// Initialize the iterator to be invalid.

        ///

        OutArcIt(Invalid) { }

        /// This constructor sets the iterator to the first outgoing arc.

        /// This constructor sets the iterator to the first outgoing arc of

        /// the node.

        OutArcIt(const Digraph&, const Node&) { }

        /// Arc -> OutArcIt conversion

        /// Sets the iterator to the value of the trivial iterator.

        /// This feature necessitates that each time we

        /// iterate the arc-set, the iteration order is the same.

        OutArcIt(const Digraph&, const Arc&) { }

        ///Next outgoing arc

        /// Assign the iterator to the next

        /// outgoing arc of the corresponding node.

        OutArcIt& operator++() { return *this; }

      };

      /// This iterator goes trough the incoming arcs of a node.

      /// This iterator goes trough the \e incoming arcs of a certain node

      /// of a digraph.

      /// Its usage is quite simple, for example you can count the number

      /// of outgoing arcs of a node \c n

      /// in digraph \c g of type \c Digraph as follows.

      ///\code

      /// int count=0;

      /// for(Digraph::InArcIt e(g, n); e!=INVALID; ++e) ++count;

      ///\endcode

      class InArcIt : public Arc {

      public:

        /// Default constructor

        /// @warning The default constructor sets the iterator

        /// to an undefined value.

        InArcIt() { }

        /// Copy constructor.

        /// Copy constructor.

        ///

        InArcIt(const InArcIt& e) : Arc(e) { }

        /// Initialize the iterator to be invalid.

        /// Initialize the iterator to be invalid.

        ///

        InArcIt(Invalid) { }

        /// This constructor sets the iterator to first incoming arc.

        /// This constructor set the iterator to the first incoming arc of

        /// the node.

        InArcIt(const Digraph&, const Node&) { }

        /// Arc -> InArcIt conversion

        /// Sets the iterator to the value of the trivial iterator \c e.

        /// This feature necessitates that each time we

        /// iterate the arc-set, the iteration order is the same.

        InArcIt(const Digraph&, const Arc&) { }

        /// Next incoming arc

        /// Assign the iterator to the next inarc of the corresponding node.

        ///

        InArcIt& operator++() { return *this; }

      };

      /// This iterator goes through each arc.

      /// This iterator goes through each arc of a digraph.

      /// Its usage is quite simple, for example you can count the number

      /// of arcs in a digraph \c g of type \c Digraph as follows:

      ///\code

      /// int count=0;

      /// for(Digraph::ArcIt e(g); e!=INVALID; ++e) ++count;

      ///\endcode

      class ArcIt : public Arc {

      public:

        /// Default constructor

        /// @warning The default constructor sets the iterator

        /// to an undefined value.

        ArcIt() { }

        /// Copy constructor.

        /// Copy constructor.

        ///

        ArcIt(const ArcIt& e) : Arc(e) { }

        /// Initialize the iterator to be invalid.

        /// Initialize the iterator to be invalid.

        ///

        ArcIt(Invalid) { }

        /// This constructor sets the iterator to the first arc.

        /// This constructor sets the iterator to the first arc of \c g.

        ///@param g the digraph

        ArcIt(const Digraph& g) { ignore_unused_variable_warning(g); }

        /// Arc -> ArcIt conversion

        /// Sets the iterator to the value of the trivial iterator \c e.

        /// This feature necessitates that each time we

        /// iterate the arc-set, the iteration order is the same.

        ArcIt(const Digraph&, const Arc&) { }

        ///Next arc

        /// Assign the iterator to the next arc.

        ArcIt& operator++() { return *this; }

      };

      ///Gives back the target node of an arc.

      ///Gives back the target node of an arc.

      ///

      Node target(Arc) const { return INVALID; }

      ///Gives back the source node of an arc.

      ///Gives back the source node of an arc.

      ///

      Node source(Arc) const { return INVALID; }

      /// \brief Returns the ID of the node.

      int id(Node) const { return -1; }

      /// \brief Returns the ID of the arc.

      int id(Arc) const { return -1; }

      /// \brief Returns the node with the given ID.

      ///

      /// \pre The argument should be a valid node ID in the graph.

      Node nodeFromId(int) const { return INVALID; }

      /// \brief Returns the arc with the given ID.

      ///

      /// \pre The argument should be a valid arc ID in the graph.

      Arc arcFromId(int) const { return INVALID; }

      /// \brief Returns an upper bound on the node IDs.

      int maxNodeId() const { return -1; }

      /// \brief Returns an upper bound on the arc IDs.

      int maxArcId() const { return -1; }

      void first(Node&) const {}

      void next(Node&) const {}

      void first(Arc&) const {}

      void next(Arc&) const {}

      void firstIn(Arc&, const Node&) const {}

      void nextIn(Arc&) const {}

      void firstOut(Arc&, const Node&) const {}

      void nextOut(Arc&) const {}

      // The second parameter is dummy.

      Node fromId(int, Node) const { return INVALID; }

      // The second parameter is dummy.

      Arc fromId(int, Arc) const { return INVALID; }

      // Dummy parameter.

      int maxId(Node) const { return -1; }

      // Dummy parameter.

      int maxId(Arc) const { return -1; }

      /// \brief The base node of the iterator.

      ///

      /// Gives back the base node of the iterator.

      /// It is always the target of the pointed arc.

      Node baseNode(const InArcIt&) const { return INVALID; }

      /// \brief The running node of the iterator.

      ///

      /// Gives back the running node of the iterator.

      /// It is always the source of the pointed arc.

      Node runningNode(const InArcIt&) const { return INVALID; }

      /// \brief The base node of the iterator.

      ///

      /// Gives back the base node of the iterator.

      /// It is always the source of the pointed arc.

      Node baseNode(const OutArcIt&) const { return INVALID; }

      /// \brief The running node of the iterator.

      ///

      /// Gives back the running node of the iterator.

      /// It is always the target of the pointed arc.

      Node runningNode(const OutArcIt&) const { return INVALID; }