/* -*- 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_CONCEPTS_DIGRAPH_H

 #define LEMON_CONCEPTS_DIGRAPH_H

 ///\ingroup graph_concepts

 ///\file

 ///\brief The concept of directed graphs.

 #include <lemon/core.h>

 #include <lemon/concepts/maps.h>

 #include <lemon/concept_check.h>

 #include <lemon/concepts/graph_components.h>

 namespace lemon {

   namespace concepts {

     /// \ingroup graph_concepts

     ///

     /// \brief Class describing the concept of directed graphs.

     ///

     /// This class describes the common interface of all directed

     /// graphs (digraphs).

     ///

     /// Like all concept classes, it only provides an interface

     /// without any sensible implementation. So any general algorithm for

     /// directed graphs should compile with this class, but it will not

     /// run properly, of course.

     /// An actual digraph implementation like \ref ListDigraph or

     /// \ref SmartDigraph may have additional functionality.

     ///

     /// \sa Graph

     class Digraph {

     private:

       /// Diraphs are \e not copy constructible. Use DigraphCopy instead.

       Digraph(const Digraph &) {}

       /// \brief Assignment of a digraph to another one is \e not allowed.

       /// Use DigraphCopy instead.

       void operator=(const Digraph &) {}

     public:

       /// Default constructor.

       Digraph() { }

       /// The node type of the digraph

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

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

       /// thus they convert to this type.

       class Node {

       public:

         /// Default constructor

         /// Default constructor.

         /// \warning It sets the object to an undefined value.

         Node() { }

         /// Copy constructor.

         /// Copy constructor.

         ///

         Node(const Node&) { }

         /// %Invalid constructor \& conversion.

         /// Initializes the object to be invalid.

         /// \sa Invalid for more details.

         Node(Invalid) { }

         /// Equality operator

         /// Equality operator.

         ///

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

         /// same object or both are \c INVALID.

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

         /// Inequality operator

         /// Inequality operator.

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

         /// Artificial ordering operator.

         /// Artificial ordering operator.

         ///

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

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

         /// ordering of the nodes.

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

       };

       /// Iterator class for the nodes.

       /// This iterator goes through each node of the digraph.

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

       /// of nodes in a 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

         /// Default constructor.

         /// \warning It sets the iterator to an undefined value.

         NodeIt() { }

         /// Copy constructor.

         /// Copy constructor.

         ///

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

         /// %Invalid constructor \& conversion.

         /// Initializes 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 the given digraph.

         ///

         explicit NodeIt(const Digraph&) { }

         /// Sets the iterator to the given node.

         /// Sets the iterator to the given node of the given digraph.

         ///

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

         /// Next node.

         /// Assign the iterator to the next node.

         ///

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

       };

       /// The arc type 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

         /// Default constructor.

         /// \warning It sets the object to an undefined value.

         Arc() { }

         /// Copy constructor.

         /// Copy constructor.

         ///

         Arc(const Arc&) { }

         /// %Invalid constructor \& conversion.

         /// Initializes the object to be invalid.

         /// \sa Invalid for more details.

         Arc(Invalid) { }

         /// Equality operator

         /// Equality operator.

         ///

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

         /// same object or both are \c INVALID.

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

         /// Inequality operator

         /// Inequality operator.

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

         /// Artificial ordering operator.

         /// Artificial ordering operator.

         ///

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

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

         /// ordering of the arcs.

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

       };

       /// Iterator class for 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 a digraph \c g of type \c %Digraph as follows.

       ///\code

       /// int count=0;

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

       ///\endcode

       class OutArcIt : public Arc {

       public:

         /// Default constructor

         /// Default constructor.

         /// \warning It sets the iterator to an undefined value.

         OutArcIt() { }

         /// Copy constructor.

         /// Copy constructor.

         ///

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

         /// %Invalid constructor \& conversion.

         /// Initializes the iterator to be invalid.

         /// \sa Invalid for more details.

         OutArcIt(Invalid) { }

         /// Sets the iterator to the first outgoing arc.

         /// Sets the iterator to the first outgoing arc of the given node.

         ///

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

         /// Sets the iterator to the given arc.

         /// Sets the iterator to the given arc of the given digraph.

         ///

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

         /// Next outgoing arc

         /// Assign the iterator to the next

         /// outgoing arc of the corresponding node.

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

       };

       /// Iterator class for 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 incoming arcs of a node \c n

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

       ///\code

       /// int count=0;

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

       ///\endcode

       class InArcIt : public Arc {

       public:

         /// Default constructor

         /// Default constructor.

         /// \warning It sets the iterator to an undefined value.

         InArcIt() { }

         /// Copy constructor.

         /// Copy constructor.

         ///

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

         /// %Invalid constructor \& conversion.

         /// Initializes the iterator to be invalid.

         /// \sa Invalid for more details.

         InArcIt(Invalid) { }

         /// Sets the iterator to the first incoming arc.

         /// Sets the iterator to the first incoming arc of the given node.

         ///

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

         /// Sets the iterator to the given arc.

         /// Sets the iterator to the given arc of the given digraph.

         ///

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

         /// Next incoming arc

         /// Assign the iterator to the next

         /// incoming arc of the corresponding node.

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

       };

       /// Iterator class for the arcs.

       /// This iterator goes through each arc of the 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 a(g); a!=INVALID; ++a) ++count;

       ///\endcode

       class ArcIt : public Arc {

       public:

         /// Default constructor

         /// Default constructor.

         /// \warning It sets the iterator to an undefined value.

         ArcIt() { }

         /// Copy constructor.

         /// Copy constructor.

         ///

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

         /// %Invalid constructor \& conversion.

         /// Initializes the iterator to be invalid.

         /// \sa Invalid for more details.

         ArcIt(Invalid) { }

         /// Sets the iterator to the first arc.

         /// Sets the iterator to the first arc of the given digraph.

         ///

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

         /// Sets the iterator to the given arc.

         /// Sets the iterator to the given arc of the given digraph.

         ///

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

         /// Next arc

         /// Assign the iterator to the next arc.

         ///

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

       };

       /// \brief The source node of the arc.

       ///

       /// Returns the source node of the given arc.

       Node source(Arc) const { return INVALID; }

       /// \brief The target node of the arc.

       ///

       /// Returns the target node of the given arc.

       Node target(Arc) const { return INVALID; }

       /// \brief The ID of the node.

       ///

       /// Returns the ID of the given node.

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

       /// \brief The ID of the arc.

       ///

       /// Returns the ID of the given arc.

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

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

       ///

       /// Returns the node with the given ID.

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

       Node nodeFromId(int) const { return INVALID; }

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

       ///

       /// Returns the arc with the given ID.

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

       Arc arcFromId(int) const { return INVALID; }

       /// \brief An upper bound on the node IDs.

       ///

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

       int maxNodeId() const { return -1; }

       /// \brief An upper bound on the arc IDs.

       ///

       /// 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 opposite node on the arc.

       ///

       /// Returns the opposite node on the given arc.

       Node oppositeNode(Node, Arc) const { return INVALID; }

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

       ///

       /// Returns the base node of the given outgoing arc iterator

       /// (i.e. the source node of the corresponding arc).

       Node baseNode(OutArcIt) const { return INVALID; }

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

       ///

       /// Returns the running node of the given outgoing arc iterator

       /// (i.e. the target node of the corresponding arc).

       Node runningNode(OutArcIt) const { return INVALID; }

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

       ///

       /// Returns the base node of the given incomming arc iterator

       /// (i.e. the target node of the corresponding arc).

       Node baseNode(InArcIt) const { return INVALID; }

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

       ///

       /// Returns the running node of the given incomming arc iterator

       /// (i.e. the source node of the corresponding arc).

       Node runningNode(InArcIt) const { return INVALID; }

       /// \brief Standard graph map type for the nodes.

       ///

       /// Standard graph map type for the nodes.

       /// It conforms to the ReferenceMap concept.

       template<class T>

       class NodeMap : public ReferenceMap<Node, T, T&, const T&> {

       public:

         /// Constructor

         explicit NodeMap(const Digraph&) { }

         /// Constructor with given initial value

         NodeMap(const Digraph&, T) { }

       private:

         ///Copy constructor

         NodeMap(const NodeMap& nm) : 

           ReferenceMap<Node, T, T&, const T&>(nm) { }

         ///Assignment operator

         template <typename CMap>

         NodeMap& operator=(const CMap&) {

           checkConcept<ReadMap<Node, T>, CMap>();

           return *this;

         }

       };

       /// \brief Standard graph map type for the arcs.

       ///

       /// Standard graph map type for the arcs.

       /// It conforms to the ReferenceMap concept.

       template<class T>

       class ArcMap : public ReferenceMap<Arc, T, T&, const T&> {

       public:

         /// Constructor

         explicit ArcMap(const Digraph&) { }

         /// Constructor with given initial value

         ArcMap(const Digraph&, T) { }

       private:

         ///Copy constructor

         ArcMap(const ArcMap& em) :

           ReferenceMap<Arc, T, T&, const T&>(em) { }

         ///Assignment operator

         template <typename CMap>

         ArcMap& operator=(const CMap&) {

           checkConcept<ReadMap<Arc, T>, CMap>();

           return *this;

         }

       };

       template <typename _Digraph>

       struct Constraints {

         void constraints() {

           checkConcept<BaseDigraphComponent, _Digraph>();

           checkConcept<IterableDigraphComponent<>, _Digraph>();

           checkConcept<IDableDigraphComponent<>, _Digraph>();

           checkConcept<MappableDigraphComponent<>, _Digraph>();

         }

       };

     };

   } //namespace concepts

 } //namespace lemon

 #endif