1 | /* -*- mode: C++; indent-tabs-mode: nil; -*- |
---|
2 | * |
---|
3 | * This file is a part of LEMON, a generic C++ optimization library. |
---|
4 | * |
---|
5 | * Copyright (C) 2003-2009 |
---|
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 concept |
---|
20 | ///\file |
---|
21 | ///\brief The concept of paths |
---|
22 | /// |
---|
23 | |
---|
24 | #ifndef LEMON_CONCEPTS_PATH_H |
---|
25 | #define LEMON_CONCEPTS_PATH_H |
---|
26 | |
---|
27 | #include <lemon/core.h> |
---|
28 | #include <lemon/concept_check.h> |
---|
29 | |
---|
30 | namespace lemon { |
---|
31 | namespace concepts { |
---|
32 | |
---|
33 | /// \addtogroup concept |
---|
34 | /// @{ |
---|
35 | |
---|
36 | /// \brief A skeleton structure for representing directed paths in |
---|
37 | /// a digraph. |
---|
38 | /// |
---|
39 | /// A skeleton structure for representing directed paths in a |
---|
40 | /// digraph. |
---|
41 | /// In a sense, a path can be treated as a list of arcs. |
---|
42 | /// LEMON path types just store this list. As a consequence, they cannot |
---|
43 | /// enumerate the nodes on the path directly and a zero length path |
---|
44 | /// cannot store its source node. |
---|
45 | /// |
---|
46 | /// The arcs of a path should be stored in the order of their directions, |
---|
47 | /// i.e. the target node of each arc should be the same as the source |
---|
48 | /// node of the next arc. This consistency could be checked using |
---|
49 | /// \ref checkPath(). |
---|
50 | /// The source and target nodes of a (consistent) path can be obtained |
---|
51 | /// using \ref pathSource() and \ref pathTarget(). |
---|
52 | /// |
---|
53 | /// A path can be constructed from another path of any type using the |
---|
54 | /// copy constructor or the assignment operator. |
---|
55 | /// |
---|
56 | /// \tparam GR The digraph type in which the path is. |
---|
57 | template <typename GR> |
---|
58 | class Path { |
---|
59 | public: |
---|
60 | |
---|
61 | /// Type of the underlying digraph. |
---|
62 | typedef GR Digraph; |
---|
63 | /// Arc type of the underlying digraph. |
---|
64 | typedef typename Digraph::Arc Arc; |
---|
65 | |
---|
66 | class ArcIt; |
---|
67 | |
---|
68 | /// \brief Default constructor |
---|
69 | Path() {} |
---|
70 | |
---|
71 | /// \brief Template copy constructor |
---|
72 | template <typename CPath> |
---|
73 | Path(const CPath& cpath) {} |
---|
74 | |
---|
75 | /// \brief Template assigment operator |
---|
76 | template <typename CPath> |
---|
77 | Path& operator=(const CPath& cpath) { |
---|
78 | ::lemon::ignore_unused_variable_warning(cpath); |
---|
79 | return *this; |
---|
80 | } |
---|
81 | |
---|
82 | /// Length of the path, i.e. the number of arcs on the path. |
---|
83 | int length() const { return 0;} |
---|
84 | |
---|
85 | /// Returns whether the path is empty. |
---|
86 | bool empty() const { return true;} |
---|
87 | |
---|
88 | /// Resets the path to an empty path. |
---|
89 | void clear() {} |
---|
90 | |
---|
91 | /// \brief LEMON style iterator for enumerating the arcs of a path. |
---|
92 | /// |
---|
93 | /// LEMON style iterator class for enumerating the arcs of a path. |
---|
94 | class ArcIt { |
---|
95 | public: |
---|
96 | /// Default constructor |
---|
97 | ArcIt() {} |
---|
98 | /// Invalid constructor |
---|
99 | ArcIt(Invalid) {} |
---|
100 | /// Sets the iterator to the first arc of the given path |
---|
101 | ArcIt(const Path &) {} |
---|
102 | |
---|
103 | /// Conversion to \c Arc |
---|
104 | operator Arc() const { return INVALID; } |
---|
105 | |
---|
106 | /// Next arc |
---|
107 | ArcIt& operator++() {return *this;} |
---|
108 | |
---|
109 | /// Comparison operator |
---|
110 | bool operator==(const ArcIt&) const {return true;} |
---|
111 | /// Comparison operator |
---|
112 | bool operator!=(const ArcIt&) const {return true;} |
---|
113 | /// Comparison operator |
---|
114 | bool operator<(const ArcIt&) const {return false;} |
---|
115 | |
---|
116 | }; |
---|
117 | |
---|
118 | template <typename _Path> |
---|
119 | struct Constraints { |
---|
120 | void constraints() { |
---|
121 | Path<Digraph> pc; |
---|
122 | _Path p, pp(pc); |
---|
123 | int l = p.length(); |
---|
124 | int e = p.empty(); |
---|
125 | p.clear(); |
---|
126 | |
---|
127 | p = pc; |
---|
128 | |
---|
129 | typename _Path::ArcIt id, ii(INVALID), i(p); |
---|
130 | |
---|
131 | ++i; |
---|
132 | typename Digraph::Arc ed = i; |
---|
133 | |
---|
134 | e = (i == ii); |
---|
135 | e = (i != ii); |
---|
136 | e = (i < ii); |
---|
137 | |
---|
138 | ::lemon::ignore_unused_variable_warning(l); |
---|
139 | ::lemon::ignore_unused_variable_warning(pp); |
---|
140 | ::lemon::ignore_unused_variable_warning(e); |
---|
141 | ::lemon::ignore_unused_variable_warning(id); |
---|
142 | ::lemon::ignore_unused_variable_warning(ii); |
---|
143 | ::lemon::ignore_unused_variable_warning(ed); |
---|
144 | } |
---|
145 | }; |
---|
146 | |
---|
147 | }; |
---|
148 | |
---|
149 | namespace _path_bits { |
---|
150 | |
---|
151 | template <typename _Digraph, typename _Path, typename RevPathTag = void> |
---|
152 | struct PathDumperConstraints { |
---|
153 | void constraints() { |
---|
154 | int l = p.length(); |
---|
155 | int e = p.empty(); |
---|
156 | |
---|
157 | typename _Path::ArcIt id, i(p); |
---|
158 | |
---|
159 | ++i; |
---|
160 | typename _Digraph::Arc ed = i; |
---|
161 | |
---|
162 | e = (i == INVALID); |
---|
163 | e = (i != INVALID); |
---|
164 | |
---|
165 | ::lemon::ignore_unused_variable_warning(l); |
---|
166 | ::lemon::ignore_unused_variable_warning(e); |
---|
167 | ::lemon::ignore_unused_variable_warning(id); |
---|
168 | ::lemon::ignore_unused_variable_warning(ed); |
---|
169 | } |
---|
170 | _Path& p; |
---|
171 | PathDumperConstraints() {} |
---|
172 | }; |
---|
173 | |
---|
174 | template <typename _Digraph, typename _Path> |
---|
175 | struct PathDumperConstraints< |
---|
176 | _Digraph, _Path, |
---|
177 | typename enable_if<typename _Path::RevPathTag, void>::type |
---|
178 | > { |
---|
179 | void constraints() { |
---|
180 | int l = p.length(); |
---|
181 | int e = p.empty(); |
---|
182 | |
---|
183 | typename _Path::RevArcIt id, i(p); |
---|
184 | |
---|
185 | ++i; |
---|
186 | typename _Digraph::Arc ed = i; |
---|
187 | |
---|
188 | e = (i == INVALID); |
---|
189 | e = (i != INVALID); |
---|
190 | |
---|
191 | ::lemon::ignore_unused_variable_warning(l); |
---|
192 | ::lemon::ignore_unused_variable_warning(e); |
---|
193 | ::lemon::ignore_unused_variable_warning(id); |
---|
194 | ::lemon::ignore_unused_variable_warning(ed); |
---|
195 | } |
---|
196 | _Path& p; |
---|
197 | PathDumperConstraints() {} |
---|
198 | }; |
---|
199 | |
---|
200 | } |
---|
201 | |
---|
202 | |
---|
203 | /// \brief A skeleton structure for path dumpers. |
---|
204 | /// |
---|
205 | /// A skeleton structure for path dumpers. The path dumpers are |
---|
206 | /// the generalization of the paths, they can enumerate the arcs |
---|
207 | /// of the path either in forward or in backward order. |
---|
208 | /// These classes are typically not used directly, they are rather |
---|
209 | /// used to be assigned to a real path type. |
---|
210 | /// |
---|
211 | /// The main purpose of this concept is that the shortest path |
---|
212 | /// algorithms can enumerate the arcs easily in reverse order. |
---|
213 | /// In LEMON, such algorithms give back a (reverse) path dumper that |
---|
214 | /// can be assigned to a real path. The dumpers can be implemented as |
---|
215 | /// an adaptor class to the predecessor map. |
---|
216 | /// |
---|
217 | /// \tparam GR The digraph type in which the path is. |
---|
218 | template <typename GR> |
---|
219 | class PathDumper { |
---|
220 | public: |
---|
221 | |
---|
222 | /// Type of the underlying digraph. |
---|
223 | typedef GR Digraph; |
---|
224 | /// Arc type of the underlying digraph. |
---|
225 | typedef typename Digraph::Arc Arc; |
---|
226 | |
---|
227 | /// Length of the path, i.e. the number of arcs on the path. |
---|
228 | int length() const { return 0;} |
---|
229 | |
---|
230 | /// Returns whether the path is empty. |
---|
231 | bool empty() const { return true;} |
---|
232 | |
---|
233 | /// \brief Forward or reverse dumping |
---|
234 | /// |
---|
235 | /// If this tag is defined to be \c True, then reverse dumping |
---|
236 | /// is provided in the path dumper. In this case, \c RevArcIt |
---|
237 | /// iterator should be implemented instead of \c ArcIt iterator. |
---|
238 | typedef False RevPathTag; |
---|
239 | |
---|
240 | /// \brief LEMON style iterator for enumerating the arcs of a path. |
---|
241 | /// |
---|
242 | /// LEMON style iterator class for enumerating the arcs of a path. |
---|
243 | class ArcIt { |
---|
244 | public: |
---|
245 | /// Default constructor |
---|
246 | ArcIt() {} |
---|
247 | /// Invalid constructor |
---|
248 | ArcIt(Invalid) {} |
---|
249 | /// Sets the iterator to the first arc of the given path |
---|
250 | ArcIt(const PathDumper&) {} |
---|
251 | |
---|
252 | /// Conversion to \c Arc |
---|
253 | operator Arc() const { return INVALID; } |
---|
254 | |
---|
255 | /// Next arc |
---|
256 | ArcIt& operator++() {return *this;} |
---|
257 | |
---|
258 | /// Comparison operator |
---|
259 | bool operator==(const ArcIt&) const {return true;} |
---|
260 | /// Comparison operator |
---|
261 | bool operator!=(const ArcIt&) const {return true;} |
---|
262 | /// Comparison operator |
---|
263 | bool operator<(const ArcIt&) const {return false;} |
---|
264 | |
---|
265 | }; |
---|
266 | |
---|
267 | /// \brief LEMON style iterator for enumerating the arcs of a path |
---|
268 | /// in reverse direction. |
---|
269 | /// |
---|
270 | /// LEMON style iterator class for enumerating the arcs of a path |
---|
271 | /// in reverse direction. |
---|
272 | class RevArcIt { |
---|
273 | public: |
---|
274 | /// Default constructor |
---|
275 | RevArcIt() {} |
---|
276 | /// Invalid constructor |
---|
277 | RevArcIt(Invalid) {} |
---|
278 | /// Sets the iterator to the last arc of the given path |
---|
279 | RevArcIt(const PathDumper &) {} |
---|
280 | |
---|
281 | /// Conversion to \c Arc |
---|
282 | operator Arc() const { return INVALID; } |
---|
283 | |
---|
284 | /// Next arc |
---|
285 | RevArcIt& operator++() {return *this;} |
---|
286 | |
---|
287 | /// Comparison operator |
---|
288 | bool operator==(const RevArcIt&) const {return true;} |
---|
289 | /// Comparison operator |
---|
290 | bool operator!=(const RevArcIt&) const {return true;} |
---|
291 | /// Comparison operator |
---|
292 | bool operator<(const RevArcIt&) const {return false;} |
---|
293 | |
---|
294 | }; |
---|
295 | |
---|
296 | template <typename _Path> |
---|
297 | struct Constraints { |
---|
298 | void constraints() { |
---|
299 | function_requires<_path_bits:: |
---|
300 | PathDumperConstraints<Digraph, _Path> >(); |
---|
301 | } |
---|
302 | }; |
---|
303 | |
---|
304 | }; |
---|
305 | |
---|
306 | |
---|
307 | ///@} |
---|
308 | } |
---|
309 | |
---|
310 | } // namespace lemon |
---|
311 | |
---|
312 | #endif |
---|