boost/graph/neighbor_bfs.hpp
// //======================================================================= // 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) //======================================================================= // #ifndef BOOST_GRAPH_NEIGHBOR_BREADTH_FIRST_SEARCH_HPP #define BOOST_GRAPH_NEIGHBOR_BREADTH_FIRST_SEARCH_HPP /* Neighbor Breadth First Search Like BFS, but traverses in-edges as well as out-edges. (for directed graphs only. use normal BFS for undirected graphs) */ #include <boost/config.hpp> #include <boost/ref.hpp> #include <vector> #include <boost/pending/queue.hpp> #include <boost/graph/graph_traits.hpp> #include <boost/graph/graph_concepts.hpp> #include <boost/graph/visitors.hpp> #include <boost/graph/named_function_params.hpp> #include <boost/concept/assert.hpp> namespace boost { template < class Visitor, class Graph > struct NeighborBFSVisitorConcept { void constraints() { BOOST_CONCEPT_ASSERT((CopyConstructibleConcept< Visitor >)); vis.initialize_vertex(u, g); vis.discover_vertex(u, g); vis.examine_vertex(u, g); vis.examine_out_edge(e, g); vis.examine_in_edge(e, g); vis.tree_out_edge(e, g); vis.tree_in_edge(e, g); vis.non_tree_out_edge(e, g); vis.non_tree_in_edge(e, g); vis.gray_target(e, g); vis.black_target(e, g); vis.gray_source(e, g); vis.black_source(e, g); vis.finish_vertex(u, g); } Visitor vis; Graph g; typename graph_traits< Graph >::vertex_descriptor u; typename graph_traits< Graph >::edge_descriptor e; }; template < class Visitors = null_visitor > class neighbor_bfs_visitor { public: neighbor_bfs_visitor(Visitors vis = Visitors()) : m_vis(vis) {} template < class Vertex, class Graph > void initialize_vertex(Vertex u, Graph& g) { invoke_visitors(m_vis, u, g, on_initialize_vertex()); } template < class Vertex, class Graph > void discover_vertex(Vertex u, Graph& g) { invoke_visitors(m_vis, u, g, on_discover_vertex()); } template < class Vertex, class Graph > void examine_vertex(Vertex u, Graph& g) { invoke_visitors(m_vis, u, g, on_examine_vertex()); } template < class Edge, class Graph > void examine_out_edge(Edge e, Graph& g) { invoke_visitors(m_vis, e, g, on_examine_edge()); } template < class Edge, class Graph > void tree_out_edge(Edge e, Graph& g) { invoke_visitors(m_vis, e, g, on_tree_edge()); } template < class Edge, class Graph > void non_tree_out_edge(Edge e, Graph& g) { invoke_visitors(m_vis, e, g, on_non_tree_edge()); } template < class Edge, class Graph > void gray_target(Edge e, Graph& g) { invoke_visitors(m_vis, e, g, on_gray_target()); } template < class Edge, class Graph > void black_target(Edge e, Graph& g) { invoke_visitors(m_vis, e, g, on_black_target()); } template < class Edge, class Graph > void examine_in_edge(Edge e, Graph& g) { invoke_visitors(m_vis, e, g, on_examine_edge()); } template < class Edge, class Graph > void tree_in_edge(Edge e, Graph& g) { invoke_visitors(m_vis, e, g, on_tree_edge()); } template < class Edge, class Graph > void non_tree_in_edge(Edge e, Graph& g) { invoke_visitors(m_vis, e, g, on_non_tree_edge()); } template < class Edge, class Graph > void gray_source(Edge e, Graph& g) { invoke_visitors(m_vis, e, g, on_gray_target()); } template < class Edge, class Graph > void black_source(Edge e, Graph& g) { invoke_visitors(m_vis, e, g, on_black_target()); } template < class Vertex, class Graph > void finish_vertex(Vertex u, Graph& g) { invoke_visitors(m_vis, u, g, on_finish_vertex()); } protected: Visitors m_vis; }; template < class Visitors > neighbor_bfs_visitor< Visitors > make_neighbor_bfs_visitor(Visitors vis) { return neighbor_bfs_visitor< Visitors >(vis); } namespace detail { template < class BidirectionalGraph, class Buffer, class BFSVisitor, class ColorMap > void neighbor_bfs_impl(const BidirectionalGraph& g, typename graph_traits< BidirectionalGraph >::vertex_descriptor s, Buffer& Q, BFSVisitor vis, ColorMap color) { BOOST_CONCEPT_ASSERT((BidirectionalGraphConcept< BidirectionalGraph >)); typedef graph_traits< BidirectionalGraph > GTraits; typedef typename GTraits::vertex_descriptor Vertex; typedef typename GTraits::edge_descriptor Edge; BOOST_CONCEPT_ASSERT( (NeighborBFSVisitorConcept< BFSVisitor, BidirectionalGraph >)); BOOST_CONCEPT_ASSERT((ReadWritePropertyMapConcept< ColorMap, Vertex >)); typedef typename property_traits< ColorMap >::value_type ColorValue; typedef color_traits< ColorValue > Color; put(color, s, Color::gray()); vis.discover_vertex(s, g); Q.push(s); while (!Q.empty()) { Vertex u = Q.top(); Q.pop(); // pop before push to avoid problem if Q is priority_queue. vis.examine_vertex(u, g); typename GTraits::out_edge_iterator ei, ei_end; for (boost::tie(ei, ei_end) = out_edges(u, g); ei != ei_end; ++ei) { Edge e = *ei; vis.examine_out_edge(e, g); Vertex v = target(e, g); ColorValue v_color = get(color, v); if (v_color == Color::white()) { vis.tree_out_edge(e, g); put(color, v, Color::gray()); vis.discover_vertex(v, g); Q.push(v); } else { vis.non_tree_out_edge(e, g); if (v_color == Color::gray()) vis.gray_target(e, g); else vis.black_target(e, g); } } // for out-edges typename GTraits::in_edge_iterator in_ei, in_ei_end; for (boost::tie(in_ei, in_ei_end) = in_edges(u, g); in_ei != in_ei_end; ++in_ei) { Edge e = *in_ei; vis.examine_in_edge(e, g); Vertex v = source(e, g); ColorValue v_color = get(color, v); if (v_color == Color::white()) { vis.tree_in_edge(e, g); put(color, v, Color::gray()); vis.discover_vertex(v, g); Q.push(v); } else { vis.non_tree_in_edge(e, g); if (v_color == Color::gray()) vis.gray_source(e, g); else vis.black_source(e, g); } } // for in-edges put(color, u, Color::black()); vis.finish_vertex(u, g); } // while } template < class VertexListGraph, class ColorMap, class BFSVisitor, class P, class T, class R > void neighbor_bfs_helper(VertexListGraph& g, typename graph_traits< VertexListGraph >::vertex_descriptor s, ColorMap color, BFSVisitor vis, const bgl_named_params< P, T, R >& params) { typedef graph_traits< VertexListGraph > Traits; // Buffer default typedef typename Traits::vertex_descriptor Vertex; typedef boost::queue< Vertex > queue_t; queue_t Q; // Initialization typedef typename property_traits< ColorMap >::value_type ColorValue; typedef color_traits< ColorValue > Color; typename boost::graph_traits< VertexListGraph >::vertex_iterator i, i_end; for (boost::tie(i, i_end) = vertices(g); i != i_end; ++i) { put(color, *i, Color::white()); vis.initialize_vertex(*i, g); } neighbor_bfs_impl(g, s, choose_param(get_param(params, buffer_param_t()), boost::ref(Q)) .get(), vis, color); } //------------------------------------------------------------------------- // Choose between default color and color parameters. Using // function dispatching so that we don't require vertex index if // the color default is not being used. template < class ColorMap > struct neighbor_bfs_dispatch { template < class VertexListGraph, class P, class T, class R > static void apply(VertexListGraph& g, typename graph_traits< VertexListGraph >::vertex_descriptor s, const bgl_named_params< P, T, R >& params, ColorMap color) { neighbor_bfs_helper(g, s, color, choose_param(get_param(params, graph_visitor), make_neighbor_bfs_visitor(null_visitor())), params); } }; template <> struct neighbor_bfs_dispatch< param_not_found > { template < class VertexListGraph, class P, class T, class R > static void apply(VertexListGraph& g, typename graph_traits< VertexListGraph >::vertex_descriptor s, const bgl_named_params< P, T, R >& params, param_not_found) { std::vector< default_color_type > color_vec(num_vertices(g)); null_visitor null_vis; neighbor_bfs_helper(g, s, make_iterator_property_map(color_vec.begin(), choose_const_pmap( get_param(params, vertex_index), g, vertex_index), color_vec[0]), choose_param(get_param(params, graph_visitor), make_neighbor_bfs_visitor(null_vis)), params); } }; } // namespace detail // Named Parameter Variant template < class VertexListGraph, class P, class T, class R > void neighbor_breadth_first_search(const VertexListGraph& g, typename graph_traits< VertexListGraph >::vertex_descriptor s, const bgl_named_params< P, T, R >& params) { // The graph is passed by *const* reference so that graph adaptors // (temporaries) can be passed into this function. However, the // graph is not really const since we may write to property maps // of the graph. VertexListGraph& ng = const_cast< VertexListGraph& >(g); typedef typename get_param_type< vertex_color_t, bgl_named_params< P, T, R > >::type C; detail::neighbor_bfs_dispatch< C >::apply( ng, s, params, get_param(params, vertex_color)); } // This version does not initialize colors, user has to. template < class IncidenceGraph, class P, class T, class R > void neighbor_breadth_first_visit(IncidenceGraph& g, typename graph_traits< IncidenceGraph >::vertex_descriptor s, const bgl_named_params< P, T, R >& params) { typedef graph_traits< IncidenceGraph > Traits; // Buffer default typedef boost::queue< typename Traits::vertex_descriptor > queue_t; queue_t Q; detail::neighbor_bfs_impl(g, s, choose_param(get_param(params, buffer_param_t()), boost::ref(Q)).get(), choose_param(get_param(params, graph_visitor), make_neighbor_bfs_visitor(null_visitor())), choose_pmap(get_param(params, vertex_color), g, vertex_color)); } } // namespace boost #endif // BOOST_GRAPH_NEIGHBOR_BREADTH_FIRST_SEARCH_HPP