williamr@2: // williamr@2: //======================================================================= williamr@2: // Copyright 1997, 1998, 1999, 2000 University of Notre Dame. williamr@2: // Authors: Andrew Lumsdaine, Lie-Quan Lee, Jeremy G. Siek williamr@2: // williamr@2: // Distributed under the Boost Software License, Version 1.0. (See williamr@2: // accompanying file LICENSE_1_0.txt or copy at williamr@2: // http://www.boost.org/LICENSE_1_0.txt) williamr@2: //======================================================================= williamr@2: // williamr@2: #ifndef BOOST_GRAPH_BREADTH_FIRST_SEARCH_HPP williamr@2: #define BOOST_GRAPH_BREADTH_FIRST_SEARCH_HPP williamr@2: williamr@2: /* williamr@2: Breadth First Search Algorithm (Cormen, Leiserson, and Rivest p. 470) williamr@2: */ williamr@2: #include williamr@2: #include williamr@2: #include williamr@2: #include williamr@2: #include williamr@2: #include williamr@2: #include williamr@2: williamr@2: namespace boost { williamr@2: williamr@2: template williamr@2: struct BFSVisitorConcept { williamr@2: void constraints() { williamr@2: function_requires< CopyConstructibleConcept >(); williamr@2: vis.initialize_vertex(u, g); williamr@2: vis.discover_vertex(u, g); williamr@2: vis.examine_vertex(u, g); williamr@2: vis.examine_edge(e, g); williamr@2: vis.tree_edge(e, g); williamr@2: vis.non_tree_edge(e, g); williamr@2: vis.gray_target(e, g); williamr@2: vis.black_target(e, g); williamr@2: vis.finish_vertex(u, g); williamr@2: } williamr@2: Visitor vis; williamr@2: Graph g; williamr@2: typename graph_traits::vertex_descriptor u; williamr@2: typename graph_traits::edge_descriptor e; williamr@2: }; williamr@2: williamr@2: williamr@2: template williamr@2: void breadth_first_visit williamr@2: (const IncidenceGraph& g, williamr@2: typename graph_traits::vertex_descriptor s, williamr@2: Buffer& Q, BFSVisitor vis, ColorMap color) williamr@2: { williamr@2: function_requires< IncidenceGraphConcept >(); williamr@2: typedef graph_traits GTraits; williamr@2: typedef typename GTraits::vertex_descriptor Vertex; williamr@2: typedef typename GTraits::edge_descriptor Edge; williamr@2: function_requires< BFSVisitorConcept >(); williamr@2: function_requires< ReadWritePropertyMapConcept >(); williamr@2: typedef typename property_traits::value_type ColorValue; williamr@2: typedef color_traits Color; williamr@2: typename GTraits::out_edge_iterator ei, ei_end; williamr@2: williamr@2: put(color, s, Color::gray()); vis.discover_vertex(s, g); williamr@2: Q.push(s); williamr@2: while (! Q.empty()) { williamr@2: Vertex u = Q.top(); Q.pop(); vis.examine_vertex(u, g); williamr@2: for (tie(ei, ei_end) = out_edges(u, g); ei != ei_end; ++ei) { williamr@2: Vertex v = target(*ei, g); vis.examine_edge(*ei, g); williamr@2: ColorValue v_color = get(color, v); williamr@2: if (v_color == Color::white()) { vis.tree_edge(*ei, g); williamr@2: put(color, v, Color::gray()); vis.discover_vertex(v, g); williamr@2: Q.push(v); williamr@2: } else { vis.non_tree_edge(*ei, g); williamr@2: if (v_color == Color::gray()) vis.gray_target(*ei, g); williamr@2: else vis.black_target(*ei, g); williamr@2: } williamr@2: } // end for williamr@2: put(color, u, Color::black()); vis.finish_vertex(u, g); williamr@2: } // end while williamr@2: } // breadth_first_visit williamr@2: williamr@2: williamr@2: template williamr@2: void breadth_first_search williamr@2: (const VertexListGraph& g, williamr@2: typename graph_traits::vertex_descriptor s, williamr@2: Buffer& Q, BFSVisitor vis, ColorMap color) williamr@2: { williamr@2: // Initialization williamr@2: typedef typename property_traits::value_type ColorValue; williamr@2: typedef color_traits Color; williamr@2: typename boost::graph_traits::vertex_iterator i, i_end; williamr@2: for (tie(i, i_end) = vertices(g); i != i_end; ++i) { williamr@2: vis.initialize_vertex(*i, g); williamr@2: put(color, *i, Color::white()); williamr@2: } williamr@2: breadth_first_visit(g, s, Q, vis, color); williamr@2: } williamr@2: williamr@2: williamr@2: template williamr@2: class bfs_visitor { williamr@2: public: williamr@2: bfs_visitor() { } williamr@2: bfs_visitor(Visitors vis) : m_vis(vis) { } williamr@2: williamr@2: template williamr@2: void initialize_vertex(Vertex u, Graph& g) { williamr@2: invoke_visitors(m_vis, u, g, ::boost::on_initialize_vertex()); williamr@2: } williamr@2: template williamr@2: void discover_vertex(Vertex u, Graph& g) { williamr@2: invoke_visitors(m_vis, u, g, ::boost::on_discover_vertex()); williamr@2: } williamr@2: template williamr@2: void examine_vertex(Vertex u, Graph& g) { williamr@2: invoke_visitors(m_vis, u, g, ::boost::on_examine_vertex()); williamr@2: } williamr@2: template williamr@2: void examine_edge(Edge e, Graph& g) { williamr@2: invoke_visitors(m_vis, e, g, ::boost::on_examine_edge()); williamr@2: } williamr@2: template williamr@2: void tree_edge(Edge e, Graph& g) { williamr@2: invoke_visitors(m_vis, e, g, ::boost::on_tree_edge()); williamr@2: } williamr@2: template williamr@2: void non_tree_edge(Edge e, Graph& g) { williamr@2: invoke_visitors(m_vis, e, g, ::boost::on_non_tree_edge()); williamr@2: } williamr@2: template williamr@2: void gray_target(Edge e, Graph& g) { williamr@2: invoke_visitors(m_vis, e, g, ::boost::on_gray_target()); williamr@2: } williamr@2: template williamr@2: void black_target(Edge e, Graph& g) { williamr@2: invoke_visitors(m_vis, e, g, ::boost::on_black_target()); williamr@2: } williamr@2: template williamr@2: void finish_vertex(Vertex u, Graph& g) { williamr@2: invoke_visitors(m_vis, u, g, ::boost::on_finish_vertex()); williamr@2: } williamr@2: williamr@2: BOOST_GRAPH_EVENT_STUB(on_initialize_vertex,bfs) williamr@2: BOOST_GRAPH_EVENT_STUB(on_discover_vertex,bfs) williamr@2: BOOST_GRAPH_EVENT_STUB(on_examine_vertex,bfs) williamr@2: BOOST_GRAPH_EVENT_STUB(on_examine_edge,bfs) williamr@2: BOOST_GRAPH_EVENT_STUB(on_tree_edge,bfs) williamr@2: BOOST_GRAPH_EVENT_STUB(on_non_tree_edge,bfs) williamr@2: BOOST_GRAPH_EVENT_STUB(on_gray_target,bfs) williamr@2: BOOST_GRAPH_EVENT_STUB(on_black_target,bfs) williamr@2: BOOST_GRAPH_EVENT_STUB(on_finish_vertex,bfs) williamr@2: williamr@2: protected: williamr@2: Visitors m_vis; williamr@2: }; williamr@2: template williamr@2: bfs_visitor williamr@2: make_bfs_visitor(Visitors vis) { williamr@2: return bfs_visitor(vis); williamr@2: } williamr@2: typedef bfs_visitor<> default_bfs_visitor; williamr@2: williamr@2: williamr@2: namespace detail { williamr@2: williamr@2: template williamr@2: void bfs_helper williamr@2: (VertexListGraph& g, williamr@2: typename graph_traits::vertex_descriptor s, williamr@2: ColorMap color, williamr@2: BFSVisitor vis, williamr@2: const bgl_named_params& params) williamr@2: { williamr@2: typedef graph_traits Traits; williamr@2: // Buffer default williamr@2: typedef typename Traits::vertex_descriptor Vertex; williamr@2: typedef boost::queue queue_t; williamr@2: queue_t Q; williamr@2: detail::wrap_ref Qref(Q); williamr@2: breadth_first_search williamr@2: (g, s, williamr@2: choose_param(get_param(params, buffer_param_t()), Qref).ref, williamr@2: vis, color); williamr@2: } williamr@2: williamr@2: //------------------------------------------------------------------------- williamr@2: // Choose between default color and color parameters. Using williamr@2: // function dispatching so that we don't require vertex index if williamr@2: // the color default is not being used. williamr@2: williamr@2: template williamr@2: struct bfs_dispatch { williamr@2: template williamr@2: static void apply williamr@2: (VertexListGraph& g, williamr@2: typename graph_traits::vertex_descriptor s, williamr@2: const bgl_named_params& params, williamr@2: ColorMap color) williamr@2: { williamr@2: bfs_helper williamr@2: (g, s, color, williamr@2: choose_param(get_param(params, graph_visitor), williamr@2: make_bfs_visitor(null_visitor())), williamr@2: params); williamr@2: } williamr@2: }; williamr@2: williamr@2: template <> williamr@2: struct bfs_dispatch { williamr@2: template williamr@2: static void apply williamr@2: (VertexListGraph& g, williamr@2: typename graph_traits::vertex_descriptor s, williamr@2: const bgl_named_params& params, williamr@2: detail::error_property_not_found) williamr@2: { williamr@2: std::vector color_vec(num_vertices(g)); williamr@2: default_color_type c = white_color; williamr@2: null_visitor null_vis; williamr@2: williamr@2: bfs_helper williamr@2: (g, s, williamr@2: make_iterator_property_map williamr@2: (color_vec.begin(), williamr@2: choose_const_pmap(get_param(params, vertex_index), williamr@2: g, vertex_index), c), williamr@2: choose_param(get_param(params, graph_visitor), williamr@2: make_bfs_visitor(null_vis)), williamr@2: params); williamr@2: } williamr@2: }; williamr@2: williamr@2: } // namespace detail williamr@2: williamr@2: williamr@2: // Named Parameter Variant williamr@2: template williamr@2: void breadth_first_search williamr@2: (const VertexListGraph& g, williamr@2: typename graph_traits::vertex_descriptor s, williamr@2: const bgl_named_params& params) williamr@2: { williamr@2: // The graph is passed by *const* reference so that graph adaptors williamr@2: // (temporaries) can be passed into this function. However, the williamr@2: // graph is not really const since we may write to property maps williamr@2: // of the graph. williamr@2: VertexListGraph& ng = const_cast(g); williamr@2: typedef typename property_value< bgl_named_params, williamr@2: vertex_color_t>::type C; williamr@2: detail::bfs_dispatch::apply(ng, s, params, williamr@2: get_param(params, vertex_color)); williamr@2: } williamr@2: williamr@2: williamr@2: // This version does not initialize colors, user has to. williamr@2: williamr@2: template williamr@2: void breadth_first_visit williamr@2: (const IncidenceGraph& g, williamr@2: typename graph_traits::vertex_descriptor s, williamr@2: const bgl_named_params& params) williamr@2: { williamr@2: // The graph is passed by *const* reference so that graph adaptors williamr@2: // (temporaries) can be passed into this function. However, the williamr@2: // graph is not really const since we may write to property maps williamr@2: // of the graph. williamr@2: IncidenceGraph& ng = const_cast(g); williamr@2: williamr@2: typedef graph_traits Traits; williamr@2: // Buffer default williamr@2: typedef typename Traits::vertex_descriptor vertex_descriptor; williamr@2: typedef boost::queue queue_t; williamr@2: queue_t Q; williamr@2: detail::wrap_ref Qref(Q); williamr@2: williamr@2: breadth_first_visit williamr@2: (ng, s, williamr@2: choose_param(get_param(params, buffer_param_t()), Qref).ref, williamr@2: choose_param(get_param(params, graph_visitor), williamr@2: make_bfs_visitor(null_visitor())), williamr@2: choose_pmap(get_param(params, vertex_color), ng, vertex_color) williamr@2: ); williamr@2: } williamr@2: williamr@2: } // namespace boost williamr@2: williamr@2: #endif // BOOST_GRAPH_BREADTH_FIRST_SEARCH_HPP williamr@2: