COIN-OR::LEMON - Graph Library

source: lemon/lemon/path_utils.h @ 96:b55e501a90ee

Last change on this file since 96:b55e501a90ee was 96:b55e501a90ee, checked in by Alpar Juttner <alpar@…>, 11 years ago

Path related files ported from svn -r3435
but ItemReader/Writer? for Path (originally belonging to path_utils.h)
hasn't ported yet.

File size: 5.8 KB
Line 
1/* -*- C++ -*-
2 *
3 * This file is a part of LEMON, a generic C++ optimization library
4 *
5 * Copyright (C) 2003-2008
6 * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport
7 * (Egervary Research Group on Combinatorial Optimization, EGRES).
8 *
9 * Permission to use, modify and distribute this software is granted
10 * provided that this copyright notice appears in all copies. For
11 * precise terms see the accompanying LICENSE file.
12 *
13 * This software is provided "AS IS" with no warranty of any kind,
14 * express or implied, and with no claim as to its suitability for any
15 * purpose.
16 *
17 */
18
19///\ingroup paths
20///\file
21///\brief Classes for representing paths in digraphs.
22///
23
24#ifndef LEMON_PATH_UTILS_H
25#define LEMON_PATH_UTILS_H
26
27#include <lemon/concepts/path.h>
28
29namespace lemon {
30
31  namespace _path_bits {
32
33    template <typename Path, typename Enable = void>
34    struct RevTagIndicator {
35      static const bool value = false;
36    };
37
38    template <typename Digraph>
39    struct RevTagIndicator<
40      Digraph,
41      typename enable_if<typename Digraph::RevTag, void>::type
42    > {
43      static const bool value = true;
44    };
45
46    template <typename Target, typename Source,
47              typename BuildEnable = void, typename RevEnable = void>
48    struct PathCopySelector {
49      static void copy(Target& target, const Source& source) {
50        target.clear();
51        for (typename Source::ArcIt it(source); it != INVALID; ++it) {
52          target.addBack(it);
53        }
54      }
55    };
56
57    template <typename Target, typename Source, typename BuildEnable>
58    struct PathCopySelector<
59      Target, Source, BuildEnable,
60      typename enable_if<typename Source::RevPathTag, void>::type> {
61      static void copy(Target& target, const Source& source) {
62        target.clear();
63        for (typename Source::RevArcIt it(source); it != INVALID; ++it) {
64          target.addFront(it);
65        }
66      }
67    };
68
69    template <typename Target, typename Source, typename RevEnable>
70    struct PathCopySelector<
71      Target, Source,
72      typename enable_if<typename Target::BuildTag, void>::type, RevEnable> {
73      static void copy(Target& target, const Source& source) {
74        target.clear();
75        target.build(source);
76      }
77    };
78
79    template <typename Target, typename Source>
80    struct PathCopySelector<
81      Target, Source,
82      typename enable_if<typename Target::BuildTag, void>::type,
83      typename enable_if<typename Source::RevPathTag, void>::type> {
84      static void copy(Target& target, const Source& source) {
85        target.clear();
86        target.buildRev(source);
87      }
88    };
89
90  }
91
92
93  /// \brief Make of copy of a path.
94  ///
95  ///  Make of copy of a path.
96  template <typename Target, typename Source>
97  void copyPath(Target& target, const Source& source) {
98    checkConcept<concepts::PathDumper<typename Source::Digraph>, Source>();
99    _path_bits::PathCopySelector<Target, Source>::copy(target, source);
100  }
101
102  /// \brief Checks the path's consistency.
103  ///
104  /// Checks that each arc's target is the next's source.
105  ///
106  template <typename Digraph, typename Path>
107  bool checkPath(const Digraph& digraph, const Path& path) {
108    typename Path::ArcIt it(path);
109    if (it == INVALID) return true;
110    typename Digraph::Node node = digraph.target(it);
111    ++it;
112    while (it != INVALID) {
113      if (digraph.source(it) != node) return false;
114      node = digraph.target(it);
115      ++it;
116    }
117    return true;
118  }
119
120  /// \brief Gives back the source of the path
121  ///
122  /// Gives back the source of the path.
123  template <typename Digraph, typename Path>
124  typename Digraph::Node pathSource(const Digraph& digraph, const Path& path) {
125    return digraph.source(path.front());
126  }
127
128  /// \brief Gives back the target of the path
129  ///
130  /// Gives back the target of the path.
131  template <typename Digraph, typename Path>
132  typename Digraph::Node pathTarget(const Digraph& digraph, const Path& path) {
133    return digraph.target(path.back());
134  }
135
136  /// \brief Class which helps to iterate the nodes of a path
137  ///
138  /// In a sense, the path can be treated as a list of arcs. The
139  /// lemon path type stores just this list. As a consequence it
140  /// cannot enumerate the nodes in the path and the zero length paths
141  /// cannot store the node.
142  ///
143  /// This class implements the node iterator of a path structure. To
144  /// provide this feature, the underlying digraph should be given to
145  /// the constructor of the iterator.
146  template <typename Path>
147  class PathNodeIt {
148  private:
149    const typename Path::Digraph *_digraph;
150    typename Path::ArcIt _it;
151    typename Path::Digraph::Node _nd;
152
153  public:
154
155    typedef typename Path::Digraph Digraph;
156    typedef typename Digraph::Node Node;
157   
158    /// Default constructor
159    PathNodeIt() {}
160    /// Invalid constructor
161    PathNodeIt(Invalid)
162      : _digraph(0), _it(INVALID), _nd(INVALID) {}
163    /// Constructor
164    PathNodeIt(const Digraph& digraph, const Path& path)
165      : _digraph(&digraph), _it(path) {
166      _nd = (_it != INVALID ? _digraph->source(_it) : INVALID);
167    }
168    /// Constructor
169    PathNodeIt(const Digraph& digraph, const Path& path, const Node& src)
170      : _digraph(&digraph), _it(path), _nd(src) {}
171
172    ///Conversion to Digraph::Node
173    operator Node() const {
174      return _nd;
175    }
176
177    /// Next node
178    PathNodeIt& operator++() {
179      if (_it == INVALID) _nd = INVALID;
180      else {
181        _nd = _digraph->target(_it);
182        ++_it;
183      }
184      return *this;
185    }
186
187    /// Comparison operator
188    bool operator==(const PathNodeIt& n) const {
189      return _it == n._it && _nd == n._nd;
190    }
191    /// Comparison operator
192    bool operator!=(const PathNodeIt& n) const {
193      return _it != n._it || _nd != n._nd;
194    }
195    /// Comparison operator
196    bool operator<(const PathNodeIt& n) const {
197      return (_it < n._it && _nd != INVALID);
198    }
199   
200  };
201 
202}
203
204#endif
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