COIN-OR::LEMON - Graph Library

source: lemon-0.x/src/lemon/smart_graph.h @ 986:e997802b855c

Last change on this file since 986:e997802b855c was 986:e997802b855c, checked in by Alpar Juttner, 16 years ago

Naming changes:

  • head -> target
  • tail -> source
File size: 8.8 KB
Line 
1/* -*- C++ -*-
2 * src/lemon/smart_graph.h - Part of LEMON, a generic C++ optimization library
3 *
4 * Copyright (C) 2004 Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport
5 * (Egervary Combinatorial Optimization Research Group, EGRES).
6 *
7 * Permission to use, modify and distribute this software is granted
8 * provided that this copyright notice appears in all copies. For
9 * precise terms see the accompanying LICENSE file.
10 *
11 * This software is provided "AS IS" with no warranty of any kind,
12 * express or implied, and with no claim as to its suitability for any
13 * purpose.
14 *
15 */
16
17#ifndef LEMON_SMART_GRAPH_H
18#define LEMON_SMART_GRAPH_H
19
20///\ingroup graphs
21///\file
22///\brief SmartGraph and SymSmartGraph classes.
23
24#include <vector>
25
26#include <lemon/invalid.h>
27
28#include <lemon/clearable_graph_extender.h>
29#include <lemon/extendable_graph_extender.h>
30#include <lemon/iterable_graph_extender.h>
31#include <lemon/alteration_observer_registry.h>
32#include <lemon/default_map.h>
33
34#include <lemon/utility.h>
35
36namespace lemon {
37
38  /// \addtogroup graphs
39  /// @{
40
41  class SmartGraph;
42  ///Base of SmartGraph
43
44  ///Base of SmartGraph
45  ///
46  class SmartGraphBase {
47
48    friend class SmatGraph;
49
50  protected:
51    struct NodeT
52    {
53      int first_in,first_out;     
54      NodeT() : first_in(-1), first_out(-1) {}
55    };
56    struct EdgeT
57    {
58      int target, source, next_in, next_out;     
59      //FIXME: is this necessary?
60      EdgeT() : next_in(-1), next_out(-1) {} 
61    };
62
63    std::vector<NodeT> nodes;
64
65    std::vector<EdgeT> edges;
66   
67   
68  public:
69
70    typedef SmartGraphBase Graph;
71
72    class Node;
73    class Edge;
74
75   
76  public:
77
78    SmartGraphBase() : nodes(), edges() { }
79    SmartGraphBase(const SmartGraphBase &_g) : nodes(_g.nodes), edges(_g.edges) { }
80   
81    typedef True NodeNumTag;
82    typedef True EdgeNumTag;
83
84    ///Number of nodes.
85    int nodeNum() const { return nodes.size(); }
86    ///Number of edges.
87    int edgeNum() const { return edges.size(); }
88
89    /// Maximum node ID.
90   
91    /// Maximum node ID.
92    ///\sa id(Node)
93    int maxId(Node = INVALID) const { return nodes.size()-1; }
94    /// Maximum edge ID.
95   
96    /// Maximum edge ID.
97    ///\sa id(Edge)
98    int maxId(Edge = INVALID) const { return edges.size()-1; }
99
100    Node source(Edge e) const { return edges[e.n].source; }
101    Node target(Edge e) const { return edges[e.n].target; }
102
103    /// Node ID.
104   
105    /// The ID of a valid Node is a nonnegative integer not greater than
106    /// \ref maxNodeId(). The range of the ID's is not surely continuous
107    /// and the greatest node ID can be actually less then \ref maxNodeId().
108    ///
109    /// The ID of the \ref INVALID node is -1.
110    ///\return The ID of the node \c v.
111    static int id(Node v) { return v.n; }
112    /// Edge ID.
113   
114    /// The ID of a valid Edge is a nonnegative integer not greater than
115    /// \ref maxEdgeId(). The range of the ID's is not surely continuous
116    /// and the greatest edge ID can be actually less then \ref maxEdgeId().
117    ///
118    /// The ID of the \ref INVALID edge is -1.
119    ///\return The ID of the edge \c e.
120    static int id(Edge e) { return e.n; }
121
122    Node addNode() {
123      Node n; n.n=nodes.size();
124      nodes.push_back(NodeT()); //FIXME: Hmmm...
125      return n;
126    }
127   
128    Edge addEdge(Node u, Node v) {
129      Edge e; e.n=edges.size(); edges.push_back(EdgeT()); //FIXME: Hmmm...
130      edges[e.n].source=u.n; edges[e.n].target=v.n;
131      edges[e.n].next_out=nodes[u.n].first_out;
132      edges[e.n].next_in=nodes[v.n].first_in;
133      nodes[u.n].first_out=nodes[v.n].first_in=e.n;
134
135      return e;
136    }
137
138    void clear() {
139      edges.clear();
140      nodes.clear();
141    }
142
143
144    class Node {
145      friend class SmartGraphBase;
146      friend class SmartGraph;
147
148    protected:
149      int n;
150      ///\todo It should be removed (or at least define a setToId() instead).
151      ///
152      Node(int nn) {n=nn;}
153    public:
154      Node() {}
155      Node (Invalid) { n=-1; }
156      bool operator==(const Node i) const {return n==i.n;}
157      bool operator!=(const Node i) const {return n!=i.n;}
158      bool operator<(const Node i) const {return n<i.n;}
159    };
160   
161
162    class Edge {
163      friend class SmartGraphBase;
164      friend class SmartGraph;
165
166    protected:
167      int n;
168      ///\todo It should be removed (or at least define a setToId() instead).
169      ///
170      Edge(int nn) {n=nn;}
171    public:
172      Edge() { }
173      Edge (Invalid) { n=-1; }
174      bool operator==(const Edge i) const {return n==i.n;}
175      bool operator!=(const Edge i) const {return n!=i.n;}
176      bool operator<(const Edge i) const {return n<i.n;}
177    };
178
179    void first(Node& node) const {
180      node.n = nodes.size() - 1;
181    }
182
183    static void next(Node& node) {
184      --node.n;
185    }
186
187    void first(Edge& edge) const {
188      edge.n = edges.size() - 1;
189    }
190
191    static void next(Edge& edge) {
192      --edge.n;
193    }
194
195    void firstOut(Edge& edge, const Node& node) const {
196      edge.n = nodes[node.n].first_out;
197    }
198
199    void nextOut(Edge& edge) const {
200      edge.n = edges[edge.n].next_out;
201    }
202
203    void firstIn(Edge& edge, const Node& node) const {
204      edge.n = nodes[node.n].first_in;
205    }
206   
207    void nextIn(Edge& edge) const {
208      edge.n = edges[edge.n].next_in;
209    }
210
211    Edge _findEdge(Node u,Node v, Edge prev = INVALID)
212    {
213      int e = (prev.n==-1)? nodes[u.n].first_out : edges[prev.n].next_out;
214      while(e!=-1 && edges[e].source!=v.n) e = edges[e].next_out;
215      prev.n=e;
216      return prev;
217    }
218
219  };
220
221  typedef AlterableGraphExtender<SmartGraphBase> AlterableSmartGraphBase;
222  typedef IterableGraphExtender<AlterableSmartGraphBase> IterableSmartGraphBase;
223  typedef DefaultMappableGraphExtender<IterableSmartGraphBase> MappableSmartGraphBase;
224  typedef ExtendableGraphExtender<MappableSmartGraphBase> ExtendableSmartGraphBase;
225  typedef ClearableGraphExtender<ExtendableSmartGraphBase> ClearableSmartGraphBase;
226
227  ///A smart graph class.
228
229  ///This is a simple and fast graph implementation.
230  ///It is also quite memory efficient, but at the price
231  ///that <b> it does support only limited (only stack-like)
232  ///node and edge deletions</b>.
233  ///It conforms to
234  ///the \ref concept::ExtendableGraph "ExtendableGraph" concept.
235  ///\sa concept::ExtendableGraph.
236  ///
237  ///\todo Some member functions could be \c static.
238  ///
239  ///\author Alpar Juttner
240  class SmartGraph : public ClearableSmartGraphBase {
241  public:
242    /// Finds an edge between two nodes.
243   
244    /// Finds an edge from node \c u to node \c v.
245    ///
246    /// If \c prev is \ref INVALID (this is the default value), then
247    /// it finds the first edge from \c u to \c v. Otherwise it looks for
248    /// the next edge from \c u to \c v after \c prev.
249    /// \return The found edge or \ref INVALID if there is no such an edge.
250    ///
251    /// Thus you can iterate through each edge from \c u to \c v as it follows.
252    /// \code
253    /// for(Edge e=G.findEdge(u,v);e!=INVALID;e=G.findEdge(u,v,e)) {
254    ///   ...
255    /// }
256    /// \endcode
257    /// \todo Possibly it should be a global function.
258    Edge findEdge(Node u,Node v, Edge prev = INVALID)
259    {
260      return _findEdge(u,v,prev);
261    }
262   
263    ///Internal data structure to store snapshots
264   
265    ///\ingroup graphs
266    ///\sa makeSnapShot()
267    ///\sa rollBack()
268    struct SnapShot
269    {
270      unsigned int node_num;
271      unsigned int edge_num;
272    };
273   
274    ///Make a snapshot of the graph.
275
276    ///Make a snapshot of the graph.
277    ///
278    ///The newly added nodes and edges can be removed using the
279    ///rollBack() function.
280    ///
281    ///\return An stucture SnapShot describing the pesent state of the
282    ///graph.
283    ///\note After you rolled back to a state, you cannot roll "back" to
284    ///a later state, in other word you cannot add again the edges deleted
285    ///by rollBack().
286    ///\todo This function might be called saveState() or getState().
287    SnapShot makeSnapShot()
288    {
289      SnapShot s;
290      s.node_num=nodes.size();
291      s.edge_num=edges.size();
292      return s;
293    }
294   
295    ///Undo the changes until a snapshot.
296
297    ///Undo the changes until a snapshot created by makeSnapShot().
298    ///
299    ///\param s an internal stucture given back by makeSnapShot()
300    ///\note After you rolled back to a state, you cannot "roll forward" to
301    ///a later state, in other word you cannot add again the edges deleted
302    ///by rollBack().
303    ///
304    ///\todo This function might be called undo().
305   
306    void rollBack(const SnapShot &s)
307    {
308      while(s.edge_num>edges.size()) {
309        edge_observers.erase(Edge(edges.size()-1));
310        nodes[edges.back().target].first_in=edges.back().next_in;
311        nodes[edges.back().source].first_out=edges.back().next_out;
312        edges.pop_back();
313      }
314      //nodes.resize(s.nodes_num);
315      while(s.node_num>nodes.size()) {
316        node_observers.erase(Node(nodes.size()-1));
317        nodes.pop_back();
318      }
319    }
320  };
321 
322  /// @} 
323} //namespace lemon
324
325
326#endif //LEMON_SMART_GRAPH_H
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