source: NonGTP/Boost/boost/graph/depth_first_search.hpp @ 857

Revision 857, 13.2 KB checked in by igarcia, 19 years ago (diff)
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1//=======================================================================
2// Copyright 1997, 1998, 1999, 2000 University of Notre Dame.
3// Copyright 2003 Bruce Barr
4// Authors: Andrew Lumsdaine, Lie-Quan Lee, Jeremy G. Siek
5//
6// Distributed under the Boost Software License, Version 1.0. (See
7// accompanying file LICENSE_1_0.txt or copy at
8// http://www.boost.org/LICENSE_1_0.txt)
9//=======================================================================
10
11// Nonrecursive implementation of depth_first_visit_impl submitted by
12// Bruce Barr, schmoost <at> yahoo.com, May/June 2003.
13#ifndef BOOST_GRAPH_RECURSIVE_DFS_HPP
14#define BOOST_GRAPH_RECURSIVE_DFS_HPP
15
16#include <boost/config.hpp>
17#include <boost/graph/graph_traits.hpp>
18#include <boost/graph/graph_concepts.hpp>
19#include <boost/graph/properties.hpp>
20#include <boost/graph/visitors.hpp>
21#include <boost/graph/named_function_params.hpp>
22
23#include <boost/ref.hpp>
24#include <boost/implicit_cast.hpp>
25
26#include <vector>
27#include <utility>
28
29namespace boost {
30
31  template <class Visitor, class Graph>
32  class DFSVisitorConcept {
33  public:
34    void constraints() {
35      function_requires< CopyConstructibleConcept<Visitor> >();
36      vis.initialize_vertex(u, g);
37      vis.start_vertex(u, g);
38      vis.discover_vertex(u, g);
39      vis.examine_edge(e, g);
40      vis.tree_edge(e, g);
41      vis.back_edge(e, g);
42      vis.forward_or_cross_edge(e, g);
43      vis.finish_vertex(u, g);
44    }
45  private:
46    Visitor vis;
47    Graph g;
48    typename graph_traits<Graph>::vertex_descriptor u;
49    typename graph_traits<Graph>::edge_descriptor e;
50  };
51
52  namespace detail {
53
54    struct nontruth2 {
55      template<class T, class T2>
56      bool operator()(const T&, const T2&) const { return false; }
57    };
58
59
60// Define BOOST_RECURSIVE_DFS to use older, recursive version.
61// It is retained for a while in order to perform performance
62// comparison.
63#ifndef BOOST_RECURSIVE_DFS
64
65    // If the vertex u and the iterators ei and ei_end are thought of as the
66    // context of the algorithm, each push and pop from the stack could
67    // be thought of as a context shift.
68    // Each pass through "while (ei != ei_end)" may refer to the out-edges of
69    // an entirely different vertex, because the context of the algorithm
70    // shifts every time a white adjacent vertex is discovered.
71    // The corresponding context shift back from the adjacent vertex occurs
72    // after all of its out-edges have been examined.
73    //
74    // See http://lists.boost.org/MailArchives/boost/msg48752.php for FAQ.
75
76    template <class IncidenceGraph, class DFSVisitor, class ColorMap,
77            class TerminatorFunc>
78    void depth_first_visit_impl
79      (const IncidenceGraph& g,
80       typename graph_traits<IncidenceGraph>::vertex_descriptor u,
81       DFSVisitor& vis,
82       ColorMap color, TerminatorFunc func = TerminatorFunc())
83    {
84      function_requires<IncidenceGraphConcept<IncidenceGraph> >();
85      function_requires<DFSVisitorConcept<DFSVisitor, IncidenceGraph> >();
86      typedef typename graph_traits<IncidenceGraph>::vertex_descriptor Vertex;
87      function_requires< ReadWritePropertyMapConcept<ColorMap, Vertex> >();
88      typedef typename property_traits<ColorMap>::value_type ColorValue;
89      function_requires< ColorValueConcept<ColorValue> >();
90      typedef color_traits<ColorValue> Color;
91      typedef typename graph_traits<IncidenceGraph>::out_edge_iterator Iter;
92      typedef std::pair<Vertex, std::pair<Iter, Iter> > VertexInfo;
93
94      Iter ei, ei_end;
95      std::vector<VertexInfo> stack;
96
97      // Possible optimization for vector
98      //stack.reserve(num_vertices(g));
99
100      typedef typename unwrap_reference<TerminatorFunc>::type TF;
101
102      put(color, u, Color::gray());
103      vis.discover_vertex(u, g);
104      tie(ei, ei_end) = out_edges(u, g);
105      // Variable is needed to workaround a borland bug.
106      TF& fn = static_cast<TF&>(func);
107      if (fn(u, g)) {
108          // If this vertex terminates the search, we push empty range
109          stack.push_back(std::make_pair(u, std::make_pair(ei_end, ei_end)));
110      } else {
111          stack.push_back(std::make_pair(u, std::make_pair(ei, ei_end)));
112      }
113      while (!stack.empty()) {
114        VertexInfo& back = stack.back();
115        u = back.first;
116        tie(ei, ei_end) = back.second;
117        stack.pop_back();
118        while (ei != ei_end) {
119          Vertex v = target(*ei, g);
120          vis.examine_edge(*ei, g);
121          ColorValue v_color = get(color, v);
122          if (v_color == Color::white()) {
123            vis.tree_edge(*ei, g);
124            stack.push_back(std::make_pair(u, std::make_pair(++ei, ei_end)));
125            u = v;
126            put(color, u, Color::gray());
127            vis.discover_vertex(u, g);
128            tie(ei, ei_end) = out_edges(u, g);
129            if (fn(u, g)) {
130                ei = ei_end;
131            }
132          } else if (v_color == Color::gray()) {
133            vis.back_edge(*ei, g);
134            ++ei;
135          } else {
136            vis.forward_or_cross_edge(*ei, g);
137            ++ei;
138          }
139        }
140        put(color, u, Color::black());
141        vis.finish_vertex(u, g);
142      }
143    }
144
145#else // BOOST_RECURSIVE_DFS is defined
146
147    template <class IncidenceGraph, class DFSVisitor, class ColorMap,
148              class TerminatorFunc>
149    void depth_first_visit_impl
150      (const IncidenceGraph& g,
151       typename graph_traits<IncidenceGraph>::vertex_descriptor u,
152       DFSVisitor& vis,  // pass-by-reference here, important!
153       ColorMap color, TerminatorFunc func)
154    {
155      function_requires<IncidenceGraphConcept<IncidenceGraph> >();
156      function_requires<DFSVisitorConcept<DFSVisitor, IncidenceGraph> >();
157      typedef typename graph_traits<IncidenceGraph>::vertex_descriptor Vertex;
158      function_requires< ReadWritePropertyMapConcept<ColorMap, Vertex> >();
159      typedef typename property_traits<ColorMap>::value_type ColorValue;
160      function_requires< ColorValueConcept<ColorValue> >();
161      typedef color_traits<ColorValue> Color;
162      typename graph_traits<IncidenceGraph>::out_edge_iterator ei, ei_end;
163
164      put(color, u, Color::gray());          vis.discover_vertex(u, g);
165
166      typedef typename unwrap_reference<TerminatorFunc>::type TF;
167      // Variable is needed to workaround a borland bug.
168      TF& fn = static_cast<TF&>(func);
169      if (!fn(u, g))
170        for (tie(ei, ei_end) = out_edges(u, g); ei != ei_end; ++ei) {
171          Vertex v = target(*ei, g);           vis.examine_edge(*ei, g);
172          ColorValue v_color = get(color, v);
173          if (v_color == Color::white()) {     vis.tree_edge(*ei, g);
174          depth_first_visit_impl(g, v, vis, color, func);
175          } else if (v_color == Color::gray()) vis.back_edge(*ei, g);
176          else                                 vis.forward_or_cross_edge(*ei, g);
177        }
178      put(color, u, Color::black());         vis.finish_vertex(u, g);
179    }
180
181#endif
182
183  } // namespace detail
184
185  template <class VertexListGraph, class DFSVisitor, class ColorMap>
186  void
187  depth_first_search(const VertexListGraph& g, DFSVisitor vis, ColorMap color,
188                     typename graph_traits<VertexListGraph>::vertex_descriptor start_vertex)
189  {
190    typedef typename graph_traits<VertexListGraph>::vertex_descriptor Vertex;
191    function_requires<DFSVisitorConcept<DFSVisitor, VertexListGraph> >();
192    typedef typename property_traits<ColorMap>::value_type ColorValue;
193    typedef color_traits<ColorValue> Color;
194
195    typename graph_traits<VertexListGraph>::vertex_iterator ui, ui_end;
196    for (tie(ui, ui_end) = vertices(g); ui != ui_end; ++ui) {
197      put(color, *ui, Color::white());       vis.initialize_vertex(*ui, g);
198    }
199
200    if (start_vertex != implicit_cast<Vertex>(*vertices(g).first)){ vis.start_vertex(start_vertex, g);
201      detail::depth_first_visit_impl(g, start_vertex, vis, color,
202                                     detail::nontruth2());
203    }
204
205    for (tie(ui, ui_end) = vertices(g); ui != ui_end; ++ui) {
206      ColorValue u_color = get(color, *ui);
207      if (u_color == Color::white()) {       vis.start_vertex(*ui, g);
208        detail::depth_first_visit_impl(g, *ui, vis, color, detail::nontruth2());
209      }
210    }
211  }
212
213  template <class VertexListGraph, class DFSVisitor, class ColorMap>
214  void
215  depth_first_search(const VertexListGraph& g, DFSVisitor vis, ColorMap color)
216  {
217    depth_first_search(g, vis, color, *vertices(g).first);
218  }
219
220  namespace detail {
221    template <class ColorMap>
222    struct dfs_dispatch {
223
224      template <class VertexListGraph, class Vertex, class DFSVisitor,
225                class P, class T, class R>
226      static void
227      apply(const VertexListGraph& g, DFSVisitor vis, Vertex start_vertex,
228            const bgl_named_params<P, T, R>&,
229            ColorMap color)
230      {
231        depth_first_search(g, vis, color, start_vertex);
232      }
233    };
234
235    template <>
236    struct dfs_dispatch<detail::error_property_not_found> {
237      template <class VertexListGraph, class Vertex, class DFSVisitor,
238                class P, class T, class R>
239      static void
240      apply(const VertexListGraph& g, DFSVisitor vis, Vertex start_vertex,
241            const bgl_named_params<P, T, R>& params,
242            detail::error_property_not_found)
243      {
244        std::vector<default_color_type> color_vec(num_vertices(g));
245        default_color_type c = white_color; // avoid warning about un-init
246        depth_first_search
247          (g, vis, make_iterator_property_map
248           (color_vec.begin(),
249            choose_const_pmap(get_param(params, vertex_index),
250                              g, vertex_index), c),
251           start_vertex);
252      }
253    };
254  } // namespace detail
255
256
257  template <class Visitors = null_visitor>
258  class dfs_visitor {
259  public:
260    dfs_visitor() { }
261    dfs_visitor(Visitors vis) : m_vis(vis) { }
262
263    template <class Vertex, class Graph>
264    void initialize_vertex(Vertex u, const Graph& g) {
265      invoke_visitors(m_vis, u, g, ::boost::on_initialize_vertex());
266    }
267    template <class Vertex, class Graph>
268    void start_vertex(Vertex u, const Graph& g) {
269      invoke_visitors(m_vis, u, g, ::boost::on_start_vertex());
270    }
271    template <class Vertex, class Graph>
272    void discover_vertex(Vertex u, const Graph& g) {
273      invoke_visitors(m_vis, u, g, ::boost::on_discover_vertex());
274    }
275    template <class Edge, class Graph>
276    void examine_edge(Edge u, const Graph& g) {
277      invoke_visitors(m_vis, u, g, ::boost::on_examine_edge());
278    }
279    template <class Edge, class Graph>
280    void tree_edge(Edge u, const Graph& g) {
281      invoke_visitors(m_vis, u, g, ::boost::on_tree_edge());
282    }
283    template <class Edge, class Graph>
284    void back_edge(Edge u, const Graph& g) {
285      invoke_visitors(m_vis, u, g, ::boost::on_back_edge());
286    }
287    template <class Edge, class Graph>
288    void forward_or_cross_edge(Edge u, const Graph& g) {
289      invoke_visitors(m_vis, u, g, ::boost::on_forward_or_cross_edge());
290    }
291    template <class Vertex, class Graph>
292    void finish_vertex(Vertex u, const Graph& g) {
293      invoke_visitors(m_vis, u, g, ::boost::on_finish_vertex());
294    }
295
296    BOOST_GRAPH_EVENT_STUB(on_initialize_vertex,dfs)
297    BOOST_GRAPH_EVENT_STUB(on_start_vertex,dfs)
298    BOOST_GRAPH_EVENT_STUB(on_discover_vertex,dfs)
299    BOOST_GRAPH_EVENT_STUB(on_examine_edge,dfs)
300    BOOST_GRAPH_EVENT_STUB(on_tree_edge,dfs)
301    BOOST_GRAPH_EVENT_STUB(on_back_edge,dfs)
302    BOOST_GRAPH_EVENT_STUB(on_forward_or_cross_edge,dfs)
303    BOOST_GRAPH_EVENT_STUB(on_finish_vertex,dfs)
304
305  protected:
306    Visitors m_vis;
307  };
308  template <class Visitors>
309  dfs_visitor<Visitors>
310  make_dfs_visitor(Visitors vis) {
311    return dfs_visitor<Visitors>(vis);
312  }
313  typedef dfs_visitor<> default_dfs_visitor;
314
315
316  // Named Parameter Variant
317  template <class VertexListGraph, class P, class T, class R>
318  void
319  depth_first_search(const VertexListGraph& g,
320                     const bgl_named_params<P, T, R>& params)
321  {
322    typedef typename property_value< bgl_named_params<P, T, R>,
323      vertex_color_t>::type C;
324    detail::dfs_dispatch<C>::apply
325      (g,
326       choose_param(get_param(params, graph_visitor),
327                    make_dfs_visitor(null_visitor())),
328       choose_param(get_param(params, root_vertex_t()),
329                    *vertices(g).first),
330       params,
331       get_param(params, vertex_color)
332       );
333  }
334
335  template <class IncidenceGraph, class DFSVisitor, class ColorMap>
336  void depth_first_visit
337    (const IncidenceGraph& g,
338     typename graph_traits<IncidenceGraph>::vertex_descriptor u,
339     DFSVisitor vis, ColorMap color)
340  {
341    vis.start_vertex(u, g);
342    detail::depth_first_visit_impl(g, u, vis, color, detail::nontruth2());
343  }
344
345  template <class IncidenceGraph, class DFSVisitor, class ColorMap,
346            class TerminatorFunc>
347  void depth_first_visit
348    (const IncidenceGraph& g,
349     typename graph_traits<IncidenceGraph>::vertex_descriptor u,
350     DFSVisitor vis, ColorMap color, TerminatorFunc func = TerminatorFunc())
351  {
352    vis.start_vertex(u, g);
353    detail::depth_first_visit_impl(g, u, vis, color, func);
354  }
355
356
357} // namespace boost
358
359
360#endif
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