1 //=======================================================================
2 // Copyright 1997, 1998, 1999, 2000 University of Notre Dame.
3 // Authors: Andrew Lumsdaine, Lie-Quan Lee, Jeremy G. Siek
4 //
5 // Distributed under the Boost Software License, Version 1.0. (See
6 // accompanying file LICENSE_1_0.txt or copy at
7 // http://www.boost.org/LICENSE_1_0.txt)
8 //=======================================================================
9 //
10 // Revision History:
11 //   01 April 2001: Modified to use new <boost/limits.hpp> header. (JMaddock)
12 //
13 #ifndef BOOST_GRAPH_GRAPH_SEARCH_VISITORS_HPP
14 #define BOOST_GRAPH_GRAPH_SEARCH_VISITORS_HPP
15 
16 #include <iosfwd>
17 #include <boost/config.hpp>
18 #include <boost/type_traits/is_same.hpp>
19 #include <boost/mpl/bool.hpp>
20 #include <boost/property_map/property_map.hpp>
21 #include <boost/graph/graph_traits.hpp>
22 #include <boost/limits.hpp>
23 
24 namespace boost {
25 
26   // This is a bit more convenient than std::numeric_limits because
27   // you don't have to explicitly provide type T.
28   template <class T>
numeric_limits_max(T)29   inline T numeric_limits_max(T) { return (std::numeric_limits<T>::max)(); }
30 
31   //========================================================================
32   // Event Tags
33 
34   namespace detail {
35     // For partial specialization workaround
36     enum event_visitor_enum
37     { on_no_event_num,
38       on_initialize_vertex_num, on_start_vertex_num,
39       on_discover_vertex_num, on_finish_vertex_num, on_examine_vertex_num,
40       on_examine_edge_num, on_tree_edge_num, on_non_tree_edge_num,
41       on_gray_target_num, on_black_target_num,
42       on_forward_or_cross_edge_num, on_back_edge_num, on_finish_edge_num,
43       on_edge_relaxed_num, on_edge_not_relaxed_num,
44       on_edge_minimized_num, on_edge_not_minimized_num
45     };
46 
47     template<typename Event, typename Visitor>
48     struct functor_to_visitor : Visitor
49     {
50       typedef Event event_filter;
functor_to_visitorboost::detail::functor_to_visitor51       functor_to_visitor(const Visitor& visitor) : Visitor(visitor) {}
52     };
53 
54   } // namespace detail
55 
56   struct on_no_event { enum { num = detail::on_no_event_num }; };
57 
58   struct on_initialize_vertex {
59     enum { num = detail::on_initialize_vertex_num }; };
60   struct on_start_vertex { enum { num = detail::on_start_vertex_num }; };
61   struct on_discover_vertex { enum { num = detail::on_discover_vertex_num }; };
62   struct on_examine_vertex { enum { num = detail::on_examine_vertex_num }; };
63   struct on_finish_vertex { enum { num = detail::on_finish_vertex_num }; };
64 
65   struct on_examine_edge { enum { num = detail::on_examine_edge_num }; };
66   struct on_tree_edge { enum { num = detail::on_tree_edge_num }; };
67   struct on_non_tree_edge { enum { num = detail::on_non_tree_edge_num }; };
68   struct on_gray_target { enum { num = detail::on_gray_target_num }; };
69   struct on_black_target { enum { num = detail::on_black_target_num }; };
70   struct on_forward_or_cross_edge {
71     enum { num = detail::on_forward_or_cross_edge_num }; };
72   struct on_back_edge { enum { num = detail::on_back_edge_num }; };
73   struct on_finish_edge { enum { num = detail::on_finish_edge_num }; };
74 
75   struct on_edge_relaxed { enum { num = detail::on_edge_relaxed_num }; };
76   struct on_edge_not_relaxed {
77     enum { num = detail::on_edge_not_relaxed_num }; };
78   struct on_edge_minimized { enum { num = detail::on_edge_minimized_num }; };
79   struct on_edge_not_minimized {
80     enum { num = detail::on_edge_not_minimized_num }; };
81 
82   //========================================================================
83   // base_visitor and null_visitor
84 
85   // needed for MSVC workaround
86   template <class Visitor>
87   struct base_visitor {
88     typedef on_no_event event_filter;
89     template <class T, class Graph>
operator ()boost::base_visitor90     void operator()(T, Graph&) { }
91   };
92 
93   struct null_visitor : public base_visitor<null_visitor> {
94     typedef on_no_event event_filter;
95     template <class T, class Graph>
operator ()boost::null_visitor96     void operator()(T, Graph&) { }
97   };
98 
99   //========================================================================
100   // The invoke_visitors() function
101 
102   namespace detail {
103     template <class Visitor, class T, class Graph>
invoke_dispatch(Visitor & v,T x,Graph & g,mpl::true_)104     inline void invoke_dispatch(Visitor& v, T x, Graph& g, mpl::true_) {
105        v(x, g);
106     }
107 
108     template <class Visitor, class T, class Graph>
invoke_dispatch(Visitor &,T,Graph &,mpl::false_)109     inline void invoke_dispatch(Visitor&, T, Graph&, mpl::false_)
110     { }
111   } // namespace detail
112 
113   template <class Visitor, class Rest, class T, class Graph, class Tag>
114   inline void
invoke_visitors(std::pair<Visitor,Rest> & vlist,T x,Graph & g,Tag tag)115   invoke_visitors(std::pair<Visitor, Rest>& vlist, T x, Graph& g, Tag tag) {
116     typedef typename Visitor::event_filter Category;
117     typedef typename is_same<Category, Tag>::type IsSameTag;
118     detail::invoke_dispatch(vlist.first, x, g, IsSameTag());
119     invoke_visitors(vlist.second, x, g, tag);
120   }
121   template <class Visitor, class T, class Graph, class Tag>
122   inline void
invoke_visitors(Visitor & v,T x,Graph & g,Tag)123   invoke_visitors(Visitor& v, T x, Graph& g, Tag) {
124     typedef typename Visitor::event_filter Category;
125     typedef typename is_same<Category, Tag>::type IsSameTag;
126     detail::invoke_dispatch(v, x, g, IsSameTag());
127   }
128 
129   //========================================================================
130   // predecessor_recorder
131 
132   template <class PredecessorMap, class Tag>
133   struct predecessor_recorder
134     : public base_visitor<predecessor_recorder<PredecessorMap, Tag> >
135   {
136     typedef Tag event_filter;
predecessor_recorderboost::predecessor_recorder137     predecessor_recorder(PredecessorMap pa) : m_predecessor(pa) { }
138     template <class Edge, class Graph>
operator ()boost::predecessor_recorder139     void operator()(Edge e, const Graph& g) {
140       put(m_predecessor, target(e, g), source(e, g));
141     }
142     PredecessorMap m_predecessor;
143   };
144   template <class PredecessorMap, class Tag>
145   predecessor_recorder<PredecessorMap, Tag>
record_predecessors(PredecessorMap pa,Tag)146   record_predecessors(PredecessorMap pa, Tag) {
147     return predecessor_recorder<PredecessorMap, Tag> (pa);
148   }
149 
150   //========================================================================
151   // edge_predecessor_recorder
152 
153   template <class PredEdgeMap, class Tag>
154   struct edge_predecessor_recorder
155     : public base_visitor<edge_predecessor_recorder<PredEdgeMap, Tag> >
156   {
157     typedef Tag event_filter;
edge_predecessor_recorderboost::edge_predecessor_recorder158     edge_predecessor_recorder(PredEdgeMap pa) : m_predecessor(pa) { }
159     template <class Edge, class Graph>
operator ()boost::edge_predecessor_recorder160     void operator()(Edge e, const Graph& g) {
161       put(m_predecessor, target(e, g), e);
162     }
163     PredEdgeMap m_predecessor;
164   };
165   template <class PredEdgeMap, class Tag>
166   edge_predecessor_recorder<PredEdgeMap, Tag>
record_edge_predecessors(PredEdgeMap pa,Tag)167   record_edge_predecessors(PredEdgeMap pa, Tag) {
168     return edge_predecessor_recorder<PredEdgeMap, Tag> (pa);
169   }
170 
171   //========================================================================
172   // distance_recorder
173 
174   template <class DistanceMap, class Tag>
175   struct distance_recorder
176     : public base_visitor<distance_recorder<DistanceMap, Tag> >
177   {
178     typedef Tag event_filter;
distance_recorderboost::distance_recorder179     distance_recorder(DistanceMap pa) : m_distance(pa) { }
180     template <class Edge, class Graph>
operator ()boost::distance_recorder181     void operator()(Edge e, const Graph& g) {
182       typename graph_traits<Graph>::vertex_descriptor
183         u = source(e, g), v = target(e, g);
184       put(m_distance, v, get(m_distance, u) + 1);
185     }
186     DistanceMap m_distance;
187   };
188   template <class DistanceMap, class Tag>
189   distance_recorder<DistanceMap, Tag>
record_distances(DistanceMap pa,Tag)190   record_distances(DistanceMap pa, Tag) {
191     return distance_recorder<DistanceMap, Tag> (pa);
192   }
193 
194   //========================================================================
195   // time_stamper
196 
197 
198   template <class TimeMap, class TimeT, class Tag>
199   struct time_stamper
200     : public base_visitor<time_stamper<TimeMap, TimeT, Tag> >
201   {
202     typedef Tag event_filter;
time_stamperboost::time_stamper203     time_stamper(TimeMap pa, TimeT& t) : m_time_pa(pa), m_time(t) { }
204     template <class Vertex, class Graph>
operator ()boost::time_stamper205     void operator()(Vertex u, const Graph&) {
206       put(m_time_pa, u, ++m_time);
207     }
208     TimeMap m_time_pa;
209     TimeT& m_time;
210   };
211   template <class TimeMap, class TimeT, class Tag>
212   time_stamper<TimeMap, TimeT, Tag>
stamp_times(TimeMap pa,TimeT & time_counter,Tag)213   stamp_times(TimeMap pa, TimeT& time_counter, Tag) {
214     return time_stamper<TimeMap, TimeT, Tag>(pa, time_counter);
215   }
216 
217   //========================================================================
218   // property_writer
219 
220   template <class PA, class OutputIterator, class Tag>
221   struct property_writer
222     : public base_visitor<property_writer<PA, OutputIterator, Tag> >
223   {
224     typedef Tag event_filter;
225 
property_writerboost::property_writer226     property_writer(PA pa, OutputIterator out) : m_pa(pa), m_out(out) { }
227 
228     template <class T, class Graph>
operator ()boost::property_writer229     void operator()(T x, Graph&) { *m_out++ = get(m_pa, x); }
230     PA m_pa;
231     OutputIterator m_out;
232   };
233   template <class PA, class OutputIterator, class Tag>
234   property_writer<PA, OutputIterator, Tag>
write_property(PA pa,OutputIterator out,Tag)235   write_property(PA pa, OutputIterator out, Tag) {
236     return property_writer<PA, OutputIterator, Tag>(pa, out);
237   }
238 
239   //========================================================================
240   // property_put
241 
242     /**
243      * Functor which just sets a given value to a vertex or edge in a property map.
244      */
245 
246   template <typename PropertyMap, typename EventTag>
247   struct property_put
248   {
249     typedef EventTag event_filter;
250 
property_putboost::property_put251     property_put (PropertyMap property_map,
252                   typename property_traits <PropertyMap>::value_type value) :
253       property_map_ (property_map), value_ (value)
254     {}
255 
256     template <typename VertexOrEdge, typename Graph>
operator ()boost::property_put257     void operator() (VertexOrEdge v, const Graph&)
258     {
259       put (property_map_, v, value_);
260     }
261 
262   private:
263     PropertyMap property_map_;
264     typename property_traits <PropertyMap>::value_type value_;
265   };
266 
267   /**
268    * Creates a property_put functor which just sets a given value to a vertex or edge.
269    *
270    * @param property_map Given writeable property map
271    * @param value Fixed value of the map
272    * @param tag Event Filter
273    * @return The functor.
274    */
275 
276     template <typename PropertyMap, typename EventTag>
277     inline property_put <PropertyMap, EventTag>
put_property(PropertyMap property_map,typename property_traits<PropertyMap>::value_type value,EventTag)278     put_property (PropertyMap property_map,
279                   typename property_traits <PropertyMap>::value_type value,
280                   EventTag)
281     {
282       return property_put <PropertyMap, EventTag> (property_map, value);
283     }
284 
285 #define BOOST_GRAPH_EVENT_STUB(Event,Kind)                                 \
286     typedef ::boost::Event Event##_type;                                   \
287     template<typename Visitor>                                             \
288     Kind##_visitor<std::pair<detail::functor_to_visitor<Event##_type,      \
289                                                      Visitor>, Visitors> > \
290     do_##Event(Visitor visitor)                                            \
291     {                                                                      \
292       typedef std::pair<detail::functor_to_visitor<Event##_type, Visitor>, \
293                         Visitors> visitor_list;                            \
294       typedef Kind##_visitor<visitor_list> result_type;                    \
295       return result_type(visitor_list(visitor, m_vis));                    \
296     }
297 
298 } /* namespace boost */
299 
300 #endif
301