1 | /* |
2 | * Copyright (c) 2018, Intel Corporation |
3 | * |
4 | * Redistribution and use in source and binary forms, with or without |
5 | * modification, are permitted provided that the following conditions are met: |
6 | * |
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9 | * * Redistributions in binary form must reproduce the above copyright |
10 | * notice, this list of conditions and the following disclaimer in the |
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12 | * * Neither the name of Intel Corporation nor the names of its contributors |
13 | * may be used to endorse or promote products derived from this software |
14 | * without specific prior written permission. |
15 | * |
16 | * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" |
17 | * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
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19 | * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE |
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21 | * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF |
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25 | * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE |
26 | * POSSIBILITY OF SUCH DAMAGE. |
27 | */ |
28 | |
29 | /** |
30 | * \file |
31 | * \brief Adaptor that presents an undirected view of a bidirectional BGL graph. |
32 | * |
33 | * Analogous to the reverse_graph adapter. You can construct one of these for |
34 | * bidirectional graph g with: |
35 | * |
36 | * auto ug = make_undirected_graph(g); |
37 | * |
38 | * The vertex descriptor type is the same as that of the underlying graph, but |
39 | * the edge descriptor is different. |
40 | */ |
41 | |
42 | #ifndef GRAPH_UNDIRECTED_H |
43 | #define GRAPH_UNDIRECTED_H |
44 | |
45 | #include "util/operators.h" |
46 | |
47 | #include <boost/graph/adjacency_iterator.hpp> |
48 | #include <boost/graph/graph_traits.hpp> |
49 | #include <boost/graph/properties.hpp> |
50 | #include <boost/iterator/iterator_facade.hpp> |
51 | |
52 | #include <type_traits> |
53 | #include <utility> |
54 | |
55 | namespace ue2 { |
56 | |
57 | struct undirected_graph_tag {}; |
58 | |
59 | template <class BidirectionalGraph, class GraphRef> |
60 | class undirected_graph; |
61 | |
62 | namespace undirected_detail { |
63 | |
64 | template <typename BidirectionalGraph> |
65 | class undirected_graph_edge_descriptor |
66 | : totally_ordered<undirected_graph_edge_descriptor<BidirectionalGraph>> { |
67 | using base_graph_type = BidirectionalGraph; |
68 | using base_graph_traits = typename boost::graph_traits<base_graph_type>; |
69 | using base_edge_type = typename base_graph_traits::edge_descriptor; |
70 | using base_vertex_type = typename base_graph_traits::vertex_descriptor; |
71 | |
72 | base_edge_type underlying_edge; |
73 | const base_graph_type *g; |
74 | bool reverse; // if true, reverse vertices in source() and target() |
75 | |
76 | inline std::pair<base_vertex_type, base_vertex_type> |
77 | canonical_edge() const { |
78 | auto u = std::min(source(underlying_edge, *g), |
79 | target(underlying_edge, *g)); |
80 | auto v = std::max(source(underlying_edge, *g), |
81 | target(underlying_edge, *g)); |
82 | return std::make_pair(u, v); |
83 | } |
84 | |
85 | template <class BidiGraph, class GraphRef> |
86 | friend class ::ue2::undirected_graph; |
87 | |
88 | public: |
89 | undirected_graph_edge_descriptor() = default; |
90 | |
91 | undirected_graph_edge_descriptor(base_edge_type edge, |
92 | const base_graph_type &g_in, |
93 | bool reverse_in) |
94 | : underlying_edge(std::move(edge)), g(&g_in), reverse(reverse_in) {} |
95 | |
96 | bool operator==(const undirected_graph_edge_descriptor &other) const { |
97 | return canonical_edge() == other.canonical_edge(); |
98 | } |
99 | |
100 | bool operator<(const undirected_graph_edge_descriptor &other) const { |
101 | return canonical_edge() < other.canonical_edge(); |
102 | } |
103 | |
104 | base_vertex_type get_source() const { |
105 | return reverse ? target(underlying_edge, *g) |
106 | : source(underlying_edge, *g); |
107 | } |
108 | |
109 | base_vertex_type get_target() const { |
110 | return reverse ? source(underlying_edge, *g) |
111 | : target(underlying_edge, *g); |
112 | } |
113 | }; |
114 | |
115 | } // namespace undirected_detail |
116 | |
117 | template <class BidirectionalGraph, class GraphRef = const BidirectionalGraph &> |
118 | class undirected_graph { |
119 | private: |
120 | using Self = undirected_graph<BidirectionalGraph, GraphRef>; |
121 | using Traits = boost::graph_traits<BidirectionalGraph>; |
122 | |
123 | public: |
124 | using base_type = BidirectionalGraph; |
125 | using base_ref_type = GraphRef; |
126 | |
127 | explicit undirected_graph(GraphRef g_in) : g(g_in) {} |
128 | |
129 | // Graph requirements |
130 | using vertex_descriptor = typename Traits::vertex_descriptor; |
131 | using edge_descriptor = |
132 | undirected_detail::undirected_graph_edge_descriptor<base_type>; |
133 | using directed_category = boost::undirected_tag; |
134 | using edge_parallel_category = boost::disallow_parallel_edge_tag; |
135 | using traversal_category = typename Traits::traversal_category; |
136 | |
137 | // IncidenceGraph requirements |
138 | |
139 | /** |
140 | * \brief Templated iterator used for out_edge_iterator and |
141 | * in_edge_iterator, depending on the value of Reverse. |
142 | */ |
143 | template <bool Reverse> |
144 | class adj_edge_iterator |
145 | : public boost::iterator_facade< |
146 | adj_edge_iterator<Reverse>, edge_descriptor, |
147 | boost::forward_traversal_tag, edge_descriptor> { |
148 | vertex_descriptor u; |
149 | const base_type *g; |
150 | typename Traits::in_edge_iterator in_it; |
151 | typename Traits::out_edge_iterator out_it; |
152 | bool done_in = false; |
153 | public: |
154 | adj_edge_iterator() = default; |
155 | |
156 | adj_edge_iterator(vertex_descriptor u_in, const base_type &g_in, |
157 | bool end_iter) |
158 | : u(std::move(u_in)), g(&g_in) { |
159 | auto pi = in_edges(u, *g); |
160 | auto po = out_edges(u, *g); |
161 | if (end_iter) { |
162 | in_it = pi.second; |
163 | out_it = po.second; |
164 | done_in = true; |
165 | } else { |
166 | in_it = pi.first; |
167 | out_it = po.first; |
168 | if (in_it == pi.second) { |
169 | done_in = true; |
170 | find_first_valid_out(); |
171 | } |
172 | } |
173 | } |
174 | |
175 | private: |
176 | friend class boost::iterator_core_access; |
177 | |
178 | void find_first_valid_out() { |
179 | auto out_end = out_edges(u, *g).second; |
180 | for (; out_it != out_end; ++out_it) { |
181 | auto v = target(*out_it, *g); |
182 | if (!edge(v, u, *g).second) { |
183 | break; |
184 | } |
185 | } |
186 | } |
187 | |
188 | void increment() { |
189 | if (!done_in) { |
190 | auto in_end = in_edges(u, *g).second; |
191 | assert(in_it != in_end); |
192 | ++in_it; |
193 | if (in_it == in_end) { |
194 | done_in = true; |
195 | find_first_valid_out(); |
196 | } |
197 | } else { |
198 | ++out_it; |
199 | find_first_valid_out(); |
200 | } |
201 | } |
202 | bool equal(const adj_edge_iterator &other) const { |
203 | return in_it == other.in_it && out_it == other.out_it; |
204 | } |
205 | edge_descriptor dereference() const { |
206 | if (done_in) { |
207 | return edge_descriptor(*out_it, *g, Reverse); |
208 | } else { |
209 | return edge_descriptor(*in_it, *g, !Reverse); |
210 | } |
211 | } |
212 | }; |
213 | |
214 | using out_edge_iterator = adj_edge_iterator<false>; |
215 | using in_edge_iterator = adj_edge_iterator<true>; |
216 | |
217 | using degree_size_type = typename Traits::degree_size_type; |
218 | |
219 | // AdjacencyGraph requirements |
220 | using adjacency_iterator = |
221 | typename boost::adjacency_iterator_generator<Self, vertex_descriptor, |
222 | out_edge_iterator>::type; |
223 | using inv_adjacency_iterator = |
224 | typename boost::inv_adjacency_iterator_generator< |
225 | Self, vertex_descriptor, in_edge_iterator>::type; |
226 | |
227 | // VertexListGraph requirements |
228 | using vertex_iterator = typename Traits::vertex_iterator; |
229 | |
230 | // EdgeListGraph requirements |
231 | enum { |
232 | is_edge_list = std::is_convertible<traversal_category, |
233 | boost::edge_list_graph_tag>::value |
234 | }; |
235 | |
236 | /** \brief Iterator used for edges(). */ |
237 | class edge_iterator |
238 | : public boost::iterator_facade<edge_iterator, edge_descriptor, |
239 | boost::forward_traversal_tag, |
240 | edge_descriptor> { |
241 | const base_type *g; |
242 | typename Traits::edge_iterator it; |
243 | public: |
244 | edge_iterator() = default; |
245 | |
246 | edge_iterator(typename Traits::edge_iterator it_in, |
247 | const base_type &g_in) |
248 | : g(&g_in), it(std::move(it_in)) { |
249 | find_first_valid_edge(); |
250 | } |
251 | |
252 | private: |
253 | friend class boost::iterator_core_access; |
254 | |
255 | void find_first_valid_edge() { |
256 | const auto end = edges(*g).second; |
257 | for (; it != end; ++it) { |
258 | const auto &u = source(*it, *g); |
259 | const auto &v = target(*it, *g); |
260 | if (!edge(v, u, *g).second) { |
261 | break; // No reverse edge, we must visit this one |
262 | } |
263 | if (u <= v) { |
264 | // We have a reverse edge, but we'll return this one (and |
265 | // skip the other). Note that (u, u) shouldn't be skipped. |
266 | break; |
267 | } |
268 | } |
269 | } |
270 | |
271 | void increment() { |
272 | assert(it != edges(*g).second); |
273 | ++it; |
274 | find_first_valid_edge(); |
275 | } |
276 | bool equal(const edge_iterator &other) const { |
277 | return it == other.it; |
278 | } |
279 | edge_descriptor dereference() const { |
280 | return edge_descriptor(*it, *g, false); |
281 | } |
282 | }; |
283 | |
284 | using vertices_size_type = typename Traits::vertices_size_type; |
285 | using edges_size_type = typename Traits::edges_size_type; |
286 | |
287 | using graph_tag = undirected_graph_tag; |
288 | |
289 | using vertex_bundle_type = |
290 | typename boost::vertex_bundle_type<base_type>::type; |
291 | using edge_bundle_type = typename boost::edge_bundle_type<base_type>::type; |
292 | |
293 | vertex_bundle_type &operator[](const vertex_descriptor &d) { |
294 | return const_cast<base_type &>(g)[d]; |
295 | } |
296 | const vertex_bundle_type &operator[](const vertex_descriptor &d) const { |
297 | return g[d]; |
298 | } |
299 | |
300 | edge_bundle_type &operator[](const edge_descriptor &d) { |
301 | return const_cast<base_type &>(g)[d.underlying_edge]; |
302 | } |
303 | const edge_bundle_type &operator[](const edge_descriptor &d) const { |
304 | return g[d.underlying_edge]; |
305 | } |
306 | |
307 | static vertex_descriptor null_vertex() { return Traits::null_vertex(); } |
308 | |
309 | // Accessor free functions follow |
310 | |
311 | friend std::pair<vertex_iterator, vertex_iterator> |
312 | vertices(const undirected_graph &ug) { |
313 | return vertices(ug.g); |
314 | } |
315 | |
316 | friend std::pair<edge_iterator, edge_iterator> |
317 | edges(const undirected_graph &ug) { |
318 | auto e = edges(ug.g); |
319 | return std::make_pair(edge_iterator(e.first, ug.g), |
320 | edge_iterator(e.second, ug.g)); |
321 | } |
322 | |
323 | friend std::pair<out_edge_iterator, out_edge_iterator> |
324 | out_edges(const vertex_descriptor &u, const undirected_graph &ug) { |
325 | return std::make_pair(out_edge_iterator(u, ug.g, false), |
326 | out_edge_iterator(u, ug.g, true)); |
327 | } |
328 | |
329 | friend vertices_size_type num_vertices(const undirected_graph &ug) { |
330 | return num_vertices(ug.g); |
331 | } |
332 | |
333 | friend edges_size_type num_edges(const undirected_graph &ug) { |
334 | auto p = edges(ug); |
335 | return std::distance(p.first, p.second); |
336 | } |
337 | |
338 | friend degree_size_type out_degree(const vertex_descriptor &u, |
339 | const undirected_graph &ug) { |
340 | return degree(u, ug); |
341 | } |
342 | |
343 | friend vertex_descriptor vertex(vertices_size_type n, |
344 | const undirected_graph &ug) { |
345 | return vertex(n, ug.g); |
346 | } |
347 | |
348 | friend std::pair<edge_descriptor, bool> edge(const vertex_descriptor &u, |
349 | const vertex_descriptor &v, |
350 | const undirected_graph &ug) { |
351 | auto e = edge(u, v, ug.g); |
352 | if (e.second) { |
353 | return std::make_pair(edge_descriptor(e.first, ug.g, false), true); |
354 | } |
355 | auto e_rev = edge(v, u, ug.g); |
356 | if (e_rev.second) { |
357 | return std::make_pair(edge_descriptor(e_rev.first, ug.g, true), |
358 | true); |
359 | } |
360 | return std::make_pair(edge_descriptor(), false); |
361 | } |
362 | |
363 | friend std::pair<in_edge_iterator, in_edge_iterator> |
364 | in_edges(const vertex_descriptor &v, const undirected_graph &ug) { |
365 | return std::make_pair(in_edge_iterator(v, ug.g, false), |
366 | in_edge_iterator(v, ug.g, true)); |
367 | } |
368 | |
369 | friend std::pair<adjacency_iterator, adjacency_iterator> |
370 | adjacent_vertices(const vertex_descriptor &u, const undirected_graph &ug) { |
371 | out_edge_iterator oi, oe; |
372 | std::tie(oi, oe) = out_edges(u, ug); |
373 | return std::make_pair(adjacency_iterator(oi, &ug), |
374 | adjacency_iterator(oe, &ug)); |
375 | } |
376 | |
377 | friend std::pair<inv_adjacency_iterator, inv_adjacency_iterator> |
378 | inv_adjacent_vertices(const vertex_descriptor &v, |
379 | const undirected_graph &ug) { |
380 | in_edge_iterator ei, ee; |
381 | std::tie(ei, ee) = in_edges(v, ug); |
382 | return std::make_pair(inv_adjacency_iterator(ei, &ug), |
383 | inv_adjacency_iterator(ee, &ug)); |
384 | } |
385 | |
386 | friend degree_size_type in_degree(const vertex_descriptor &v, |
387 | const undirected_graph &ug) { |
388 | return degree(v, ug); |
389 | } |
390 | |
391 | friend vertex_descriptor source(const edge_descriptor &e, |
392 | const undirected_graph &) { |
393 | return e.get_source(); |
394 | } |
395 | |
396 | friend vertex_descriptor target(const edge_descriptor &e, |
397 | const undirected_graph &) { |
398 | return e.get_target(); |
399 | } |
400 | |
401 | friend degree_size_type degree(const vertex_descriptor &u, |
402 | const undirected_graph &ug) { |
403 | auto p = out_edges(u, ug); |
404 | return std::distance(p.first, p.second); |
405 | } |
406 | |
407 | // Property accessors. |
408 | |
409 | template <typename Property> |
410 | using prop_map = typename boost::property_map<undirected_graph, Property>; |
411 | |
412 | template <typename Property> |
413 | friend typename prop_map<Property>::type |
414 | get(Property p, undirected_graph &ug) { |
415 | return get(p, ug.g); |
416 | } |
417 | |
418 | template <typename Property> |
419 | friend typename prop_map<Property>::const_type |
420 | get(Property p, const undirected_graph &ug) { |
421 | return get(p, ug.g); |
422 | } |
423 | |
424 | template <typename Property, typename Key> |
425 | friend typename boost::property_traits< |
426 | typename prop_map<Property>::const_type>::value_type |
427 | get(Property p, const undirected_graph &ug, const Key &k) { |
428 | return get(p, ug.g, get_underlying_descriptor(k)); |
429 | } |
430 | |
431 | template <typename Property, typename Value, typename Key> |
432 | friend void put(Property p, const undirected_graph &ug, |
433 | const Key &k, const Value &val) { |
434 | put(p, const_cast<BidirectionalGraph &>(ug.g), |
435 | get_underlying_descriptor(k), val); |
436 | } |
437 | |
438 | private: |
439 | // Accessors are here because our free friend functions (above) cannot see |
440 | // edge_descriptor's private members. |
441 | static typename base_type::vertex_descriptor |
442 | get_underlying_descriptor(const vertex_descriptor &v) { |
443 | return v; |
444 | } |
445 | static typename base_type::edge_descriptor |
446 | get_underlying_descriptor(const edge_descriptor &e) { |
447 | return e.underlying_edge; |
448 | } |
449 | |
450 | // Reference to underlying bidirectional graph |
451 | GraphRef g; |
452 | }; |
453 | |
454 | template <class BidirectionalGraph> |
455 | undirected_graph<BidirectionalGraph> |
456 | make_undirected_graph(const BidirectionalGraph &g) { |
457 | return undirected_graph<BidirectionalGraph>(g); |
458 | } |
459 | |
460 | } // namespace ue2 |
461 | |
462 | namespace boost { |
463 | |
464 | /* Derive all the property map specializations from the underlying |
465 | * bidirectional graph. */ |
466 | |
467 | template <typename BidirectionalGraph, typename GraphRef, typename Property> |
468 | struct property_map<ue2::undirected_graph<BidirectionalGraph, GraphRef>, |
469 | Property> { |
470 | using base_map_type = property_map<BidirectionalGraph, Property>; |
471 | using type = typename base_map_type::type; |
472 | using const_type = typename base_map_type::const_type; |
473 | }; |
474 | |
475 | template <class BidirectionalGraph, class GraphRef> |
476 | struct vertex_property_type<ue2::undirected_graph<BidirectionalGraph, GraphRef>> |
477 | : vertex_property_type<BidirectionalGraph> {}; |
478 | |
479 | template <class BidirectionalGraph, class GraphRef> |
480 | struct edge_property_type<ue2::undirected_graph<BidirectionalGraph, GraphRef>> |
481 | : edge_property_type<BidirectionalGraph> {}; |
482 | |
483 | template <class BidirectionalGraph, class GraphRef> |
484 | struct graph_property_type<ue2::undirected_graph<BidirectionalGraph, GraphRef>> |
485 | : graph_property_type<BidirectionalGraph> {}; |
486 | |
487 | template <typename BidirectionalGraph, typename GraphRef> |
488 | struct vertex_bundle_type<ue2::undirected_graph<BidirectionalGraph, GraphRef>> |
489 | : vertex_bundle_type<BidirectionalGraph> {}; |
490 | |
491 | template <typename BidirectionalGraph, typename GraphRef> |
492 | struct edge_bundle_type<ue2::undirected_graph<BidirectionalGraph, GraphRef>> |
493 | : edge_bundle_type<BidirectionalGraph> {}; |
494 | |
495 | template <typename BidirectionalGraph, typename GraphRef> |
496 | struct graph_bundle_type<ue2::undirected_graph<BidirectionalGraph, GraphRef>> |
497 | : graph_bundle_type<BidirectionalGraph> {}; |
498 | |
499 | } // namespace boost |
500 | |
501 | #endif // GRAPH_UNDIRECTED_H |
502 | |