source: lemon-0.x/src/hugo/skeletons/graph.h @ 872:c010b38ea35b

// -*- c++ -*-
#ifndef HUGO_SKELETON_GRAPH_H
#define HUGO_SKELETON_GRAPH_H

///\ingroup skeletons
///\file
///\brief Declaration of GraphSkeleton.

#include <hugo/invalid.h>
#include <hugo/skeletons/maps.h>

/// The namespace of HugoLib
namespace hugo {
  namespace skeleton {
    
    /// \addtogroup skeletons
    /// @{

    /// An empty static graph class.
  
    /// This class provides all the common features of a graph structure,
    /// however completely without implementations and real data structures
    /// behind the interface.
    /// All graph algorithms should compile with this class, but it will not
    /// run properly, of course.
    ///
    /// It can be used for checking the interface compatibility,
    /// or it can serve as a skeleton of a new graph structure.
    /// 
    /// Also, you will find here the full documentation of a certain graph
    /// feature, the documentation of a real graph imlementation
    /// like @ref ListGraph or
    /// @ref SmartGraph will just refer to this structure.
    class StaticGraphSkeleton
    {
    public:
      /// Defalult constructor.

      /// Defalult constructor.
      ///
      StaticGraphSkeleton() { }
      ///Copy consructor.

//       ///\todo It is not clear, what we expect from a copy constructor.
//       ///E.g. How to assign the nodes/edges to each other? What about maps?
//       StaticGraphSkeleton(const StaticGraphSkeleton& g) { }

      /// The base type of node iterators, 
      /// or in other words, the trivial node iterator.

      /// This is the base type of each node iterator,
      /// thus each kind of node iterator converts to this.
      /// More precisely each kind of node iterator should be inherited 
      /// from the trivial node iterator.
      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 \ref operator==(Node n)
        ///
        bool operator!=(Node) const { return true; }

        ///Comparison operator.

        ///This is a strict ordering between the nodes.
        ///
        ///This ordering can be different from the order in which NodeIt
        ///goes through the nodes.
        ///\todo Possibly we don't need it.
        bool operator<(Node) const { return true; }
      };
    
      /// 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 graph \c g of type \c Graph like this:
      /// \code
      /// int count=0;
      /// for (Graph::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&) { }
        /// 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 StaticGraphSkeleton& g) { }
        /// Node -> NodeIt conversion.

        /// Sets the iterator to the node of \c g pointed by the trivial 
        /// iterator n.
        /// This feature necessitates that each time we 
        /// iterate the edge-set, the iteration order is the same.
        NodeIt(const StaticGraphSkeleton& g, const Node& n) { }
        /// Next node.

        /// Assign the iterator to the next node.
        ///
        NodeIt& operator++() { return *this; }
      };
    
    
      /// The base type of the edge iterators.

      /// The base type of the edge iterators.
      ///
      class Edge {
      public:
        /// Default constructor

        /// @warning The default constructor sets the iterator
        /// to an undefined value.
        Edge() { }
        /// Copy constructor.

        /// Copy constructor.
        ///
        Edge(const Edge&) { }
        /// Initialize the iterator to be invalid.

        /// Initialize the iterator to be invalid.
        ///
        Edge(Invalid) { }
        /// Equality operator

        /// Two iterators are equal if and only if they point to the
        /// same object or both are invalid.
        bool operator==(Edge) const { return true; }
        /// Inequality operator

        /// \sa \ref operator==(Node n)
        ///
        bool operator!=(Edge) const { return true; }
        ///Comparison operator.

        ///This is a strict ordering between the nodes.
        ///
        ///This ordering can be different from the order in which NodeIt
        ///goes through the nodes.
        ///\todo Possibly we don't need it.
        bool operator<(Edge) const { return true; }
      };
    
      /// This iterator goes trough the outgoing edges of a node.

      /// This iterator goes trough the \e outgoing edges of a certain node
      /// of a graph.
      /// Its usage is quite simple, for example you can count the number
      /// of outgoing edges of a node \c n
      /// in graph \c g of type \c Graph as follows.
      /// \code
      /// int count=0;
      /// for (Graph::OutEdgeIt e(g, n); e!=INVALID; ++e) ++count;
      /// \endcode
    
      class OutEdgeIt : public Edge {
      public:
        /// Default constructor

        /// @warning The default constructor sets the iterator
        /// to an undefined value.
        OutEdgeIt() { }
        /// Copy constructor.

        /// Copy constructor.
        ///
        OutEdgeIt(const OutEdgeIt&) { }
        /// Initialize the iterator to be invalid.

        /// Initialize the iterator to be invalid.
        ///
        OutEdgeIt(Invalid) { }
        /// This constructor sets the iterator to first outgoing edge.
    
        /// This constructor set the iterator to the first outgoing edge of
        /// node
        ///@param n the node
        ///@param g the graph
        OutEdgeIt(const StaticGraphSkeleton& g, const Node& n) { }
        /// Edge -> OutEdgeIt conversion

        /// Sets the iterator to the value of the trivial iterator \c e.
        /// This feature necessitates that each time we 
        /// iterate the edge-set, the iteration order is the same.
        OutEdgeIt(const StaticGraphSkeleton& g, const Edge& e) { }
        ///Next outgoing edge
        
        /// Assign the iterator to the next 
        /// outgoing edge of the corresponding node.
        OutEdgeIt& operator++() { return *this; }
      };

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

      /// This iterator goes trough the \e incoming edges of a certain node
      /// of a graph.
      /// Its usage is quite simple, for example you can count the number
      /// of outgoing edges of a node \c n
      /// in graph \c g of type \c Graph as follows.
      /// \code
      /// int count=0;
      /// for(Graph::InEdgeIt e(g, n); e!=INVALID; ++e) ++count;
      /// \endcode

      class InEdgeIt : public Edge {
      public:
        /// Default constructor

        /// @warning The default constructor sets the iterator
        /// to an undefined value.
        InEdgeIt() { }
        /// Copy constructor.

        /// Copy constructor.
        ///
        InEdgeIt(const InEdgeIt&) { }
        /// Initialize the iterator to be invalid.

        /// Initialize the iterator to be invalid.
        ///
        InEdgeIt(Invalid) { }
        /// This constructor sets the iterator to first incoming edge.
    
        /// This constructor set the iterator to the first incoming edge of
        /// node
        ///@param n the node
        ///@param g the graph
        InEdgeIt(const StaticGraphSkeleton& g, const Node& n) { }
        /// Edge -> InEdgeIt conversion

        /// Sets the iterator to the value of the trivial iterator \c e.
        /// This feature necessitates that each time we 
        /// iterate the edge-set, the iteration order is the same.
        InEdgeIt(const StaticGraphSkeleton& g, const Edge& n) { }
        /// Next incoming edge

        /// Assign the iterator to the next inedge of the corresponding node.
        ///
        InEdgeIt& operator++() { return *this; }
      };
      /// This iterator goes through each edge.

      /// This iterator goes through each edge of a graph.
      /// Its usage is quite simple, for example you can count the number
      /// of edges in a graph \c g of type \c Graph as follows:
      /// \code
      /// int count=0;
      /// for(Graph::EdgeIt e(g); e!=INVALID; ++e) ++count;
      /// \endcode
      class EdgeIt : public Edge {
      public:
        /// Default constructor

        /// @warning The default constructor sets the iterator
        /// to an undefined value.
        EdgeIt() { }
        /// Copy constructor.

        /// Copy constructor.
        ///
        EdgeIt(const EdgeIt&) { }
        /// Initialize the iterator to be invalid.

        /// Initialize the iterator to be invalid.
        ///
        EdgeIt(Invalid) { }
        /// This constructor sets the iterator to first edge.
    
        /// This constructor set the iterator to the first edge of
        /// node
        ///@param g the graph
        EdgeIt(const StaticGraphSkeleton& g) { }
        /// Edge -> EdgeIt conversion

        /// Sets the iterator to the value of the trivial iterator \c e.
        /// This feature necessitates that each time we 
        /// iterate the edge-set, the iteration order is the same.
        EdgeIt(const StaticGraphSkeleton&, const Edge&) { } 
        ///Next edge
        
        /// Assign the iterator to the next 
        /// edge of the corresponding node.
        EdgeIt& operator++() { return *this; }
      };

      /// First node of the graph.

      /// \retval i the first node.
      /// \return the first node.
      ///
      NodeIt& first(NodeIt& i) const { return i; }

      /// The first incoming edge.

      /// The first incoming edge.
      ///
      InEdgeIt& first(InEdgeIt &i, Node) const { return i; }
      /// The first outgoing edge.

      /// The first outgoing edge.
      ///
      OutEdgeIt& first(OutEdgeIt& i, Node) const { return i; }
      /// The first edge of the Graph.

      /// The first edge of the Graph.
      ///
      EdgeIt& first(EdgeIt& i) const { return i; }

      ///Gives back the head node of an edge.

      ///Gives back the head node of an edge.
      ///
      Node head(Edge) const { return INVALID; }
      ///Gives back the tail node of an edge.

      ///Gives back the tail node of an edge.
      ///
      Node tail(Edge) const { return INVALID; }
  
      ///Gives back the \e id of a node.

      ///\warning Not all graph structures provide this feature.
      ///
      ///\todo Should each graph provide \c id?
      int id(const Node&) const { return 0; }
      ///Gives back the \e id of an edge.

      ///\warning Not all graph structures provide this feature.
      ///
      ///\todo Should each graph provide \c id?
      int id(const Edge&) const { return 0; }

      /// .
      
      ///\todo What is this?
      ///
      int nodeNum() const { return 0; }
      /// .
      ///\todo What is this?
      ///
      int edgeNum() const { return 0; }


      ///Reference map of the nodes to type \c T.

      ///Reference map of the nodes to type \c T.
      /// \sa ReferenceSkeleton
      /// \warning Making maps that can handle bool type (NodeMap<bool>)
      /// needs some extra attention!
      template<class T> class NodeMap: public ReferenceMap< Node, T >
      {
      public:

        /// .
        NodeMap(const StaticGraphSkeleton&) { }
        /// .
        NodeMap(const StaticGraphSkeleton&, T) { }

        ///Copy constructor
        template<typename TT> NodeMap(const NodeMap<TT>&) { }
        ///Assignment operator
        template<typename TT> NodeMap& operator=(const NodeMap<TT>&)
        { return *this; }
      };

      ///Reference map of the edges to type \c T.

      ///Reference map of the edges to type \c T.
      /// \sa ReferenceSkeleton
      /// \warning Making maps that can handle bool type (EdgeMap<bool>)
      /// needs some extra attention!
      template<class T> class EdgeMap
        : public ReferenceMap<Edge,T>
      {
      public:

        /// .
        EdgeMap(const StaticGraphSkeleton&) { }
        /// .
        EdgeMap(const StaticGraphSkeleton&, T) { }
    
        ///Copy constructor
        template<typename TT> EdgeMap(const EdgeMap<TT>&) { }
        ///Assignment operator
        template<typename TT> EdgeMap &operator=(const EdgeMap<TT>&)
        { return *this; }
      };
    };


  
    /// An empty non-static graph class.

    /// This class provides everything that \c StaticGraphSkeleton
    /// with additional functionality which enables to build a
    /// graph from scratch.
    class GraphSkeleton : public StaticGraphSkeleton
    {
    public:
      /// Defalult constructor.

      /// Defalult constructor.
      ///
      GraphSkeleton() { }
      ///Add a new node to the graph.

      /// \return the new node.
      ///
      Node addNode() { return INVALID; }
      ///Add a new edge to the graph.

      ///Add a new edge to the graph with tail node \c tail
      ///and head node \c head.
      ///\return the new edge.
      Edge addEdge(Node, Node) { return INVALID; }
    
      /// Resets the graph.

      /// This function deletes all edges and nodes of the graph.
      /// It also frees the memory allocated to store them.
      /// \todo It might belong to \c ErasableGraphSkeleton.
      void clear() { }
    };

    /// An empty erasable graph class.
  
    /// This class is an extension of \c GraphSkeleton. It also makes it
    /// possible to erase edges or nodes.
    class ErasableGraphSkeleton : public GraphSkeleton
    {
    public:
      /// Defalult constructor.

      /// Defalult constructor.
      ///
      ErasableGraphSkeleton() { }
      /// Deletes a node.

      /// Deletes node \c n node.
      ///
      void erase(Node n) { }
      /// Deletes an edge.

      /// Deletes edge \c e edge.
      ///
      void erase(Edge e) { }
    };

    // @}
  } //namespace skeleton  
} //namespace hugo



#endif // HUGO_SKELETON_GRAPH_H