lemon/bits/graph_extender.h
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     1 /* -*- C++ -*-
       
     2  * lemon/graph_extender.h - Part of LEMON, a generic C++ optimization library
       
     3  *
       
     4  * Copyright (C) 2005 Egervary Jeno Kombinatorikus Optimalizalasi
       
     5  * Kutatocsoport (Egervary Research Group on Combinatorial Optimization,
       
     6  * EGRES).
       
     7  *
       
     8  * Permission to use, modify and distribute this software is granted
       
     9  * provided that this copyright notice appears in all copies. For
       
    10  * precise terms see the accompanying LICENSE file.
       
    11  *
       
    12  * This software is provided "AS IS" with no warranty of any kind,
       
    13  * express or implied, and with no claim as to its suitability for any
       
    14  * purpose.
       
    15  *
       
    16  */
       
    17 
       
    18 #ifndef LEMON_GRAPH_EXTENDER_H
       
    19 #define LEMON_GRAPH_EXTENDER_H
       
    20 
       
    21 #include <lemon/invalid.h>
       
    22 
       
    23 namespace lemon {
       
    24 
       
    25   template <typename _Base>
       
    26   class GraphExtender : public _Base {
       
    27   public:
       
    28 
       
    29     typedef _Base Parent;
       
    30     typedef GraphExtender Graph;
       
    31 
       
    32     typedef typename Parent::Node Node;
       
    33     typedef typename Parent::Edge Edge;
       
    34 
       
    35     int maxId(Node) const {
       
    36       return Parent::maxNodeId();
       
    37     }
       
    38 
       
    39     int maxId(Edge) const {
       
    40       return Parent::maxEdgeId();
       
    41     }
       
    42 
       
    43     Node fromId(int id, Node) const {
       
    44       return Parent::nodeFromId(id);
       
    45     }
       
    46 
       
    47     Edge fromId(int id, Edge) const {
       
    48       return Parent::edgeFromId(id);
       
    49     }
       
    50 
       
    51     Node oppositeNode(const Node &n, const Edge &e) const {
       
    52       if (n == Parent::source(e))
       
    53 	return Parent::target(e);
       
    54       else if(n==Parent::target(e))
       
    55 	return Parent::source(e);
       
    56       else
       
    57 	return INVALID;
       
    58     }
       
    59 
       
    60   };
       
    61 
       
    62   template <typename _Base>
       
    63   class UndirGraphExtender : public _Base {
       
    64     typedef _Base Parent;
       
    65     typedef UndirGraphExtender Graph;
       
    66 
       
    67   public:
       
    68 
       
    69     typedef typename Parent::Edge UndirEdge;
       
    70     typedef typename Parent::Node Node;
       
    71 
       
    72     class Edge : public UndirEdge {
       
    73       friend class UndirGraphExtender;
       
    74 
       
    75     protected:
       
    76       // FIXME: Marci use opposite logic in his graph adaptors. It would
       
    77       // be reasonable to syncronize...
       
    78       bool forward;
       
    79 
       
    80       Edge(const UndirEdge &ue, bool _forward) :
       
    81         UndirEdge(ue), forward(_forward) {}
       
    82 
       
    83     public:
       
    84       Edge() {}
       
    85 
       
    86       /// Invalid edge constructor
       
    87       Edge(Invalid i) : UndirEdge(i), forward(true) {}
       
    88 
       
    89       bool operator==(const Edge &that) const {
       
    90 	return forward==that.forward && UndirEdge(*this)==UndirEdge(that);
       
    91       }
       
    92       bool operator!=(const Edge &that) const {
       
    93 	return forward!=that.forward || UndirEdge(*this)!=UndirEdge(that);
       
    94       }
       
    95       bool operator<(const Edge &that) const {
       
    96 	return forward<that.forward ||
       
    97 	  (!(that.forward<forward) && UndirEdge(*this)<UndirEdge(that));
       
    98       }
       
    99     };
       
   100 
       
   101 
       
   102     /// \brief Edge of opposite direction.
       
   103     ///
       
   104     /// Returns the Edge of opposite direction.
       
   105     Edge oppositeEdge(const Edge &e) const {
       
   106       return Edge(e,!e.forward);
       
   107     }
       
   108 
       
   109   public:
       
   110     /// \todo Shouldn't the "source" of an undirected edge be called "aNode"
       
   111     /// or something???
       
   112     using Parent::source;
       
   113 
       
   114     /// Source of the given Edge.
       
   115     Node source(const Edge &e) const {
       
   116       return e.forward ? Parent::source(e) : Parent::target(e);
       
   117     }
       
   118 
       
   119     /// \todo Shouldn't the "target" of an undirected edge be called "bNode"
       
   120     /// or something???
       
   121     using Parent::target;
       
   122 
       
   123     /// Target of the given Edge.
       
   124     Node target(const Edge &e) const {
       
   125       return e.forward ? Parent::target(e) : Parent::source(e);
       
   126     }
       
   127 
       
   128     Node oppositeNode(const Node &n, const UndirEdge &e) const {
       
   129       if( n == Parent::source(e))
       
   130 	return Parent::target(e);
       
   131       else if( n == Parent::target(e))
       
   132 	return Parent::source(e);
       
   133       else
       
   134 	return INVALID;
       
   135     }
       
   136 
       
   137     /// \brief Directed edge from an undirected edge and a source node.
       
   138     ///
       
   139     /// Returns a (directed) Edge corresponding to the specified UndirEdge
       
   140     /// and source Node.
       
   141     ///
       
   142     Edge direct(const UndirEdge &ue, const Node &s) const {
       
   143       return Edge(ue, s == source(ue));
       
   144     }
       
   145 
       
   146     /// \brief Directed edge from an undirected edge.
       
   147     ///
       
   148     /// Returns a directed edge corresponding to the specified UndirEdge.
       
   149     /// If the given bool is true the given undirected edge and the
       
   150     /// returned edge have the same source node.
       
   151     Edge direct(const UndirEdge &ue, bool d) const {
       
   152       return Edge(ue, d);
       
   153     }
       
   154 
       
   155     /// Returns whether the given directed edge is same orientation as the
       
   156     /// corresponding undirected edge.
       
   157     ///
       
   158     /// \todo reference to the corresponding point of the undirected graph
       
   159     /// concept. "What does the direction of an undirected edge mean?"
       
   160     bool direction(const Edge &e) const { return e.forward; }
       
   161 
       
   162 
       
   163     using Parent::first;
       
   164     void first(Edge &e) const {
       
   165       Parent::first(e);
       
   166       e.forward=true;
       
   167     }
       
   168 
       
   169     using Parent::next;
       
   170     void next(Edge &e) const {
       
   171       if( e.forward ) {
       
   172 	e.forward = false;
       
   173       }
       
   174       else {
       
   175 	Parent::next(e);
       
   176 	e.forward = true;
       
   177       }
       
   178     }
       
   179 
       
   180   public:
       
   181 
       
   182     void firstOut(Edge &e, const Node &n) const {
       
   183       Parent::firstIn(e,n);
       
   184       if( UndirEdge(e) != INVALID ) {
       
   185 	e.forward = false;
       
   186       }
       
   187       else {
       
   188 	Parent::firstOut(e,n);
       
   189 	e.forward = true;
       
   190       }
       
   191     }
       
   192     void nextOut(Edge &e) const {
       
   193       if( ! e.forward ) {
       
   194 	Node n = Parent::target(e);
       
   195 	Parent::nextIn(e);
       
   196 	if( UndirEdge(e) == INVALID ) {
       
   197 	  Parent::firstOut(e, n);
       
   198 	  e.forward = true;
       
   199 	}
       
   200       }
       
   201       else {
       
   202 	Parent::nextOut(e);
       
   203       }
       
   204     }
       
   205 
       
   206     void firstIn(Edge &e, const Node &n) const {
       
   207       Parent::firstOut(e,n);
       
   208       if( UndirEdge(e) != INVALID ) {
       
   209 	e.forward = false;
       
   210       }
       
   211       else {
       
   212 	Parent::firstIn(e,n);
       
   213 	e.forward = true;
       
   214       }
       
   215     }
       
   216     void nextIn(Edge &e) const {
       
   217       if( ! e.forward ) {
       
   218 	Node n = Parent::source(e);
       
   219 	Parent::nextOut(e);
       
   220 	if( UndirEdge(e) == INVALID ) {
       
   221 	  Parent::firstIn(e, n);
       
   222 	  e.forward = true;
       
   223 	}
       
   224       }
       
   225       else {
       
   226 	Parent::nextIn(e);
       
   227       }
       
   228     }
       
   229 
       
   230     void firstInc(UndirEdge &e, const Node &n) const {
       
   231       Parent::firstOut(e, n);
       
   232       if (e != INVALID) return;
       
   233       Parent::firstIn(e, n);
       
   234     }
       
   235     void nextInc(UndirEdge &e, const Node &n) const {
       
   236       if (Parent::source(e) == n) {
       
   237 	Parent::nextOut(e);
       
   238 	if (e != INVALID) return;
       
   239 	Parent::firstIn(e, n);
       
   240       } else {
       
   241 	Parent::nextIn(e);
       
   242       }
       
   243     }
       
   244 
       
   245     void firstInc(UndirEdge &e, bool &d, const Node &n) const {
       
   246       d = true;
       
   247       Parent::firstOut(e, n);
       
   248       if (e != INVALID) return;
       
   249       d = false;
       
   250       Parent::firstIn(e, n);
       
   251     }
       
   252     void nextInc(UndirEdge &e, bool &d) const {
       
   253       if (d) {
       
   254 	Node s = Parent::source(e);
       
   255 	Parent::nextOut(e);
       
   256 	if (e != INVALID) return;
       
   257 	d = false;
       
   258 	Parent::firstIn(e, s);
       
   259       } else {
       
   260 	Parent::nextIn(e);
       
   261       }
       
   262     }
       
   263 
       
   264     // Miscellaneous stuff:
       
   265 
       
   266     /// \todo these methods (id, maxEdgeId) should be moved into separate
       
   267     /// Extender
       
   268 
       
   269     // using Parent::id;
       
   270     // Using "using" is not a good idea, cause it could be that there is
       
   271     // no "id" in Parent...
       
   272 
       
   273     int id(const Node &n) const {
       
   274       return Parent::id(n);
       
   275     }
       
   276 
       
   277     int id(const UndirEdge &e) const {
       
   278       return Parent::id(e);
       
   279     }
       
   280 
       
   281     int id(const Edge &e) const {
       
   282       return 2 * Parent::id(e) + int(e.forward);
       
   283     }
       
   284 
       
   285     int maxNodeId() const {
       
   286       return Parent::maxNodeId();
       
   287     }
       
   288 
       
   289     int maxEdgeId() const {
       
   290       return 2 * Parent::maxEdgeId() + 1;
       
   291     }
       
   292 
       
   293     int maxUndirEdgeId() const {
       
   294       return Parent::maxEdgeId();
       
   295     }
       
   296 
       
   297     int maxId(Node) const {
       
   298       return maxNodeId();
       
   299     }
       
   300 
       
   301     int maxId(Edge) const {
       
   302       return maxEdgeId();
       
   303     }
       
   304     int maxId(UndirEdge) const {
       
   305       return maxUndirEdgeId();
       
   306     }
       
   307 
       
   308     int edgeNum() const {
       
   309       return 2 * Parent::edgeNum();
       
   310     }
       
   311 
       
   312     int undirEdgeNum() const {
       
   313       return Parent::edgeNum();
       
   314     }
       
   315 
       
   316     Node nodeFromId(int id) const {
       
   317       return Parent::nodeFromId(id);
       
   318     }
       
   319 
       
   320     Edge edgeFromId(int id) const {
       
   321       return direct(Parent::edgeFromId(id >> 1), bool(id & 1));
       
   322     }
       
   323 
       
   324     UndirEdge undirEdgeFromId(int id) const {
       
   325       return Parent::edgeFromId(id >> 1);
       
   326     }
       
   327 
       
   328     Node fromId(int id, Node) const {
       
   329       return nodeFromId(id);
       
   330     }
       
   331 
       
   332     Edge fromId(int id, Edge) const {
       
   333       return edgeFromId(id);
       
   334     }
       
   335 
       
   336     UndirEdge fromId(int id, UndirEdge) const {
       
   337       return undirEdgeFromId(id);
       
   338     }
       
   339 
       
   340 
       
   341     Edge findEdge(Node source, Node target, Edge prev) const {
       
   342       if (prev == INVALID) {
       
   343 	UndirEdge edge = Parent::findEdge(source, target);
       
   344 	if (edge != INVALID) return direct(edge, true);
       
   345 	edge = Parent::findEdge(target, source);
       
   346 	if (edge != INVALID) return direct(edge, false);
       
   347       } else if (direction(prev)) {
       
   348 	UndirEdge edge = Parent::findEdge(source, target, prev);
       
   349 	if (edge != INVALID) return direct(edge, true);
       
   350 	edge = Parent::findEdge(target, source);
       
   351 	if (edge != INVALID) return direct(edge, false);	
       
   352       } else {
       
   353 	UndirEdge edge = Parent::findEdge(target, source, prev);
       
   354 	if (edge != INVALID) return direct(edge, false);	      
       
   355       }
       
   356       return INVALID;
       
   357     }
       
   358 
       
   359     UndirEdge findUndirEdge(Node source, Node target, UndirEdge prev) const {
       
   360       if (prev == INVALID) {
       
   361 	UndirEdge edge = Parent::findEdge(source, target);
       
   362 	if (edge != INVALID) return edge;
       
   363 	edge = Parent::findEdge(target, source);
       
   364 	if (edge != INVALID) return edge;
       
   365       } else if (Parent::source(prev) == source) {
       
   366 	UndirEdge edge = Parent::findEdge(source, target, prev);
       
   367 	if (edge != INVALID) return edge;
       
   368 	edge = Parent::findEdge(target, source);
       
   369 	if (edge != INVALID) return edge;	
       
   370       } else {
       
   371 	UndirEdge edge = Parent::findEdge(target, source, prev);
       
   372 	if (edge != INVALID) return edge;	      
       
   373       }
       
   374       return INVALID;
       
   375     }
       
   376 
       
   377   };
       
   378 
       
   379 }
       
   380 
       
   381 #endif // LEMON_UNDIR_GRAPH_EXTENDER_H