//=======================================================================

 // Copyright 1997, 1998, 1999, 2000 University of Notre Dame.

 // Authors: Andrew Lumsdaine, Lie-Quan Lee, Jeremy G. Siek

 //

 // Distributed under the Boost Software License, Version 1.0. (See

 // accompanying file LICENSE_1_0.txt or copy at

 // http://www.boost.org/LICENSE_1_0.txt)

 //=======================================================================

 //

 // Revision History:

 //   01 April 2001: Modified to use new <boost/limits.hpp> header. (JMaddock)

 //

 #ifndef BOOST_GRAPH_GRAPH_SEARCH_VISITORS_HPP

 #define BOOST_GRAPH_GRAPH_SEARCH_VISITORS_HPP

 #include <iosfwd>

 #include <boost/config.hpp>

 #include <boost/property_map.hpp>

 #include <boost/graph/graph_traits.hpp>

 #include <boost/limits.hpp>

 #include <boost/graph/detail/is_same.hpp>

 namespace boost {

   // This is a bit more convenient than std::numeric_limits because

   // you don't have to explicitly provide type T.

   template <class T>

   inline T numeric_limits_max(T) { return (std::numeric_limits<T>::max)(); }

   //========================================================================

   // Event Tags

   namespace detail {

     // For partial specialization workaround

     enum event_visitor_enum

     { on_no_event_num,

       on_initialize_vertex_num, on_start_vertex_num,

       on_discover_vertex_num, on_finish_vertex_num, on_examine_vertex_num,

       on_examine_edge_num, on_tree_edge_num, on_non_tree_edge_num,

       on_gray_target_num, on_black_target_num,

       on_forward_or_cross_edge_num, on_back_edge_num,

       on_edge_relaxed_num, on_edge_not_relaxed_num,

       on_edge_minimized_num, on_edge_not_minimized_num

     };

     template<typename Event, typename Visitor>

     struct functor_to_visitor : Visitor

     {

       typedef Event event_filter;

       functor_to_visitor(const Visitor& visitor) : Visitor(visitor) {}

     };

   } // namespace detail

   struct on_no_event { enum { num = detail::on_no_event_num }; };

   struct on_initialize_vertex {

     enum { num = detail::on_initialize_vertex_num }; };

   struct on_start_vertex { enum { num = detail::on_start_vertex_num }; };

   struct on_discover_vertex { enum { num = detail::on_discover_vertex_num }; };

   struct on_examine_vertex { enum { num = detail::on_examine_vertex_num }; };

   struct on_finish_vertex { enum { num = detail::on_finish_vertex_num }; };

   struct on_examine_edge { enum { num = detail::on_examine_edge_num }; };

   struct on_tree_edge { enum { num = detail::on_tree_edge_num }; };

   struct on_non_tree_edge { enum { num = detail::on_non_tree_edge_num }; };

   struct on_gray_target { enum { num = detail::on_gray_target_num }; };

   struct on_black_target { enum { num = detail::on_black_target_num }; };

   struct on_forward_or_cross_edge {

     enum { num = detail::on_forward_or_cross_edge_num }; };

   struct on_back_edge { enum { num = detail::on_back_edge_num }; };

   struct on_edge_relaxed { enum { num = detail::on_edge_relaxed_num }; };

   struct on_edge_not_relaxed {

     enum { num = detail::on_edge_not_relaxed_num }; };

   struct on_edge_minimized { enum { num = detail::on_edge_minimized_num }; };

   struct on_edge_not_minimized {

     enum { num = detail::on_edge_not_minimized_num }; };

   struct true_tag { enum { num = true }; };

   struct false_tag { enum { num = false }; };

   //========================================================================

   // base_visitor and null_visitor

   // needed for MSVC workaround

   template <class Visitor>

   struct base_visitor {

     typedef on_no_event event_filter;

     template <class T, class Graph>

     void operator()(T, Graph&) { }

   };

   struct null_visitor : public base_visitor<null_visitor> {

     typedef on_no_event event_filter;

     template <class T, class Graph>

     void operator()(T, Graph&) { }

   };

   //========================================================================

   // The invoke_visitors() function

   namespace detail {

     template <class Visitor, class T, class Graph>

     inline void

     invoke_dispatch(Visitor& v, T x, Graph& g, true_tag) {

        v(x, g);

     }

     template <class Visitor, class T, class Graph>

     inline void

     invoke_dispatch(Visitor&, T, Graph&, false_tag) { }

   } // namespace detail

   template <class Visitor, class Rest, class T, class Graph, class Tag>

   inline void

   invoke_visitors(std::pair<Visitor, Rest>& vlist, T x, Graph& g, Tag tag) {

     typedef typename Visitor::event_filter Category;

     typedef typename graph_detail::is_same<Category, Tag>::is_same_tag

       IsSameTag;

     detail::invoke_dispatch(vlist.first, x, g, IsSameTag());

     invoke_visitors(vlist.second, x, g, tag);

   }

 #if defined(BOOST_MSVC) && BOOST_MSVC <= 1300

   template <class Visitor, class T, class Graph, class Tag>

   inline void

   invoke_visitors(base_visitor<Visitor>& vis, T x, Graph& g, Tag) {

     typedef typename Visitor::event_filter Category;

     typedef typename graph_detail::is_same<Category, Tag>::is_same_tag

       IsSameTag;

     Visitor& v = static_cast<Visitor&>(vis);

     detail::invoke_dispatch(v, x, g, IsSameTag());

   }

 #else

   template <class Visitor, class T, class Graph, class Tag>

   inline void

   invoke_visitors(Visitor& v, T x, Graph& g, Tag) {

     typedef typename Visitor::event_filter Category;

     typedef typename graph_detail::is_same<Category, Tag>::is_same_tag

       IsSameTag;

     detail::invoke_dispatch(v, x, g, IsSameTag());

   }

 #endif

   //========================================================================

   // predecessor_recorder

   template <class PredecessorMap, class Tag>

   struct predecessor_recorder

     : public base_visitor<predecessor_recorder<PredecessorMap, Tag> >

   {

     typedef Tag event_filter;

     predecessor_recorder(PredecessorMap pa) : m_predecessor(pa) { }

     template <class Edge, class Graph>

     void operator()(Edge e, const Graph& g) {

       put(m_predecessor, target(e, g), source(e, g));

     }

     PredecessorMap m_predecessor;

   };

   template <class PredecessorMap, class Tag>

   predecessor_recorder<PredecessorMap, Tag>

   record_predecessors(PredecessorMap pa, Tag) {

     return predecessor_recorder<PredecessorMap, Tag> (pa);

   }

   //========================================================================

   // edge_predecessor_recorder

   template <class PredEdgeMap, class Tag>

   struct edge_predecessor_recorder

     : public base_visitor<edge_predecessor_recorder<PredEdgeMap, Tag> >

   {

     typedef Tag event_filter;

     edge_predecessor_recorder(PredEdgeMap pa) : m_predecessor(pa) { }

     template <class Edge, class Graph>

     void operator()(Edge e, const Graph& g) {

       put(m_predecessor, target(e, g), e);

     }

     PredEdgeMap m_predecessor;

   };

   template <class PredEdgeMap, class Tag>

   edge_predecessor_recorder<PredEdgeMap, Tag>

   record_edge_predecessors(PredEdgeMap pa, Tag) {

     return edge_predecessor_recorder<PredEdgeMap, Tag> (pa);

   }

   //========================================================================

   // distance_recorder

   template <class DistanceMap, class Tag>

   struct distance_recorder

     : public base_visitor<distance_recorder<DistanceMap, Tag> >

   {

     typedef Tag event_filter;

     distance_recorder(DistanceMap pa) : m_distance(pa) { }

     template <class Edge, class Graph>

     void operator()(Edge e, const Graph& g) {

       typename graph_traits<Graph>::vertex_descriptor

         u = source(e, g), v = target(e, g);

       put(m_distance, v, get(m_distance, u) + 1);

     }

     DistanceMap m_distance;

   };

   template <class DistanceMap, class Tag>

   distance_recorder<DistanceMap, Tag>

   record_distances(DistanceMap pa, Tag) {

     return distance_recorder<DistanceMap, Tag> (pa);

   }

   //========================================================================

   // time_stamper

   template <class TimeMap, class TimeT, class Tag>

   struct time_stamper

     : public base_visitor<time_stamper<TimeMap, TimeT, Tag> >

   {

     typedef Tag event_filter;

     time_stamper(TimeMap pa, TimeT& t) : m_time_pa(pa), m_time(t) { }

     template <class Vertex, class Graph>

     void operator()(Vertex u, const Graph&) {

       put(m_time_pa, u, ++m_time);

     }

     TimeMap m_time_pa;

     TimeT& m_time;

   };

   template <class TimeMap, class TimeT, class Tag>

   time_stamper<TimeMap, TimeT, Tag>

   stamp_times(TimeMap pa, TimeT& time_counter, Tag) {

     return time_stamper<TimeMap, TimeT, Tag>(pa, time_counter);

   }

   //========================================================================

   // property_writer

   template <class PA, class OutputIterator, class Tag>

   struct property_writer

     : public base_visitor<property_writer<PA, OutputIterator, Tag> >

   {

     typedef Tag event_filter;

     property_writer(PA pa, OutputIterator out) : m_pa(pa), m_out(out) { }

     template <class T, class Graph>

     void operator()(T x, Graph&) { *m_out++ = get(m_pa, x); }

     PA m_pa;

     OutputIterator m_out;

   };

   template <class PA, class OutputIterator, class Tag>

   property_writer<PA, OutputIterator, Tag>

   write_property(PA pa, OutputIterator out, Tag) {

     return property_writer<PA, OutputIterator, Tag>(pa, out);

   }

 #define BOOST_GRAPH_EVENT_STUB(Event,Kind)                                 \

     typedef ::boost::Event Event##_type;                                   \

     template<typename Visitor>                                             \

     Kind##_visitor<std::pair<detail::functor_to_visitor<Event##_type,      \

                                                      Visitor>, Visitors> > \

     do_##Event(Visitor visitor)                                            \

     {                                                                      \

       typedef std::pair<detail::functor_to_visitor<Event##_type, Visitor>, \

                         Visitors> visitor_list;                            \

       typedef Kind##_visitor<visitor_list> result_type;                    \

       return result_type(visitor_list(visitor, m_vis));                    \

     }

 } /* namespace boost */

 #endif