williamr@2: //=======================================================================
williamr@2: // Copyright 1997, 1998, 1999, 2000 University of Notre Dame.
williamr@2: // Copyright 2003 Bruce Barr
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: // Nonrecursive implementation of depth_first_visit_impl submitted by
williamr@2: // Bruce Barr, schmoost <at> yahoo.com, May/June 2003.
williamr@2: #ifndef BOOST_GRAPH_RECURSIVE_DFS_HPP
williamr@2: #define BOOST_GRAPH_RECURSIVE_DFS_HPP
williamr@2: 
williamr@2: #include <boost/config.hpp>
williamr@2: #include <boost/graph/graph_traits.hpp>
williamr@2: #include <boost/graph/graph_concepts.hpp>
williamr@2: #include <boost/graph/properties.hpp>
williamr@2: #include <boost/graph/visitors.hpp>
williamr@2: #include <boost/graph/named_function_params.hpp>
williamr@2: 
williamr@2: #include <boost/ref.hpp>
williamr@2: #include <boost/implicit_cast.hpp>
williamr@2: 
williamr@2: #include <vector>
williamr@2: #include <utility>
williamr@2: 
williamr@2: namespace boost {
williamr@2: 
williamr@2:   template <class Visitor, class Graph>
williamr@2:   class DFSVisitorConcept {
williamr@2:   public:
williamr@2:     void constraints() {
williamr@2:       function_requires< CopyConstructibleConcept<Visitor> >();
williamr@2:       vis.initialize_vertex(u, g);
williamr@2:       vis.start_vertex(u, g);
williamr@2:       vis.discover_vertex(u, g);
williamr@2:       vis.examine_edge(e, g);
williamr@2:       vis.tree_edge(e, g);
williamr@2:       vis.back_edge(e, g);
williamr@2:       vis.forward_or_cross_edge(e, g);
williamr@2:       vis.finish_vertex(u, g);
williamr@2:     }
williamr@2:   private:
williamr@2:     Visitor vis;
williamr@2:     Graph g;
williamr@2:     typename graph_traits<Graph>::vertex_descriptor u;
williamr@2:     typename graph_traits<Graph>::edge_descriptor e;
williamr@2:   };
williamr@2: 
williamr@2:   namespace detail {
williamr@2: 
williamr@2:     struct nontruth2 {
williamr@2:       template<class T, class T2>
williamr@2:       bool operator()(const T&, const T2&) const { return false; }
williamr@2:     };
williamr@2: 
williamr@2: 
williamr@2: // Define BOOST_RECURSIVE_DFS to use older, recursive version.
williamr@2: // It is retained for a while in order to perform performance
williamr@2: // comparison.
williamr@2: #ifndef BOOST_RECURSIVE_DFS
williamr@2: 
williamr@2:     // If the vertex u and the iterators ei and ei_end are thought of as the
williamr@2:     // context of the algorithm, each push and pop from the stack could
williamr@2:     // be thought of as a context shift.
williamr@2:     // Each pass through "while (ei != ei_end)" may refer to the out-edges of
williamr@2:     // an entirely different vertex, because the context of the algorithm
williamr@2:     // shifts every time a white adjacent vertex is discovered.
williamr@2:     // The corresponding context shift back from the adjacent vertex occurs
williamr@2:     // after all of its out-edges have been examined.
williamr@2:     //
williamr@2:     // See http://lists.boost.org/MailArchives/boost/msg48752.php for FAQ.
williamr@2: 
williamr@2:     template <class IncidenceGraph, class DFSVisitor, class ColorMap,
williamr@2:             class TerminatorFunc>
williamr@2:     void depth_first_visit_impl
williamr@2:       (const IncidenceGraph& g,
williamr@2:        typename graph_traits<IncidenceGraph>::vertex_descriptor u,
williamr@2:        DFSVisitor& vis,
williamr@2:        ColorMap color, TerminatorFunc func = TerminatorFunc())
williamr@2:     {
williamr@2:       function_requires<IncidenceGraphConcept<IncidenceGraph> >();
williamr@2:       function_requires<DFSVisitorConcept<DFSVisitor, IncidenceGraph> >();
williamr@2:       typedef typename graph_traits<IncidenceGraph>::vertex_descriptor Vertex;
williamr@2:       function_requires< ReadWritePropertyMapConcept<ColorMap, Vertex> >();
williamr@2:       typedef typename property_traits<ColorMap>::value_type ColorValue;
williamr@2:       function_requires< ColorValueConcept<ColorValue> >();
williamr@2:       typedef color_traits<ColorValue> Color;
williamr@2:       typedef typename graph_traits<IncidenceGraph>::out_edge_iterator Iter;
williamr@2:       typedef std::pair<Vertex, std::pair<Iter, Iter> > VertexInfo;
williamr@2: 
williamr@2:       Iter ei, ei_end;
williamr@2:       std::vector<VertexInfo> stack;
williamr@2: 
williamr@2:       // Possible optimization for vector
williamr@2:       //stack.reserve(num_vertices(g));
williamr@2: 
williamr@2:       typedef typename unwrap_reference<TerminatorFunc>::type TF;
williamr@2: 
williamr@2:       put(color, u, Color::gray());
williamr@2:       vis.discover_vertex(u, g);
williamr@2:       tie(ei, ei_end) = out_edges(u, g);
williamr@2:       // Variable is needed to workaround a borland bug.
williamr@2:       TF& fn = static_cast<TF&>(func);
williamr@2:       if (fn(u, g)) {
williamr@2:           // If this vertex terminates the search, we push empty range
williamr@2:           stack.push_back(std::make_pair(u, std::make_pair(ei_end, ei_end)));
williamr@2:       } else {
williamr@2:           stack.push_back(std::make_pair(u, std::make_pair(ei, ei_end)));
williamr@2:       }
williamr@2:       while (!stack.empty()) {
williamr@2:         VertexInfo& back = stack.back();
williamr@2:         u = back.first;
williamr@2:         tie(ei, ei_end) = back.second;
williamr@2:         stack.pop_back();
williamr@2:         while (ei != ei_end) {
williamr@2:           Vertex v = target(*ei, g);
williamr@2:           vis.examine_edge(*ei, g);
williamr@2:           ColorValue v_color = get(color, v);
williamr@2:           if (v_color == Color::white()) {
williamr@2:             vis.tree_edge(*ei, g);
williamr@2:             stack.push_back(std::make_pair(u, std::make_pair(++ei, ei_end)));
williamr@2:             u = v;
williamr@2:             put(color, u, Color::gray());
williamr@2:             vis.discover_vertex(u, g);
williamr@2:             tie(ei, ei_end) = out_edges(u, g);
williamr@2:             if (fn(u, g)) {
williamr@2:                 ei = ei_end;
williamr@2:             }
williamr@2:           } else if (v_color == Color::gray()) {
williamr@2:             vis.back_edge(*ei, g);
williamr@2:             ++ei;
williamr@2:           } else {
williamr@2:             vis.forward_or_cross_edge(*ei, g);
williamr@2:             ++ei;
williamr@2:           }
williamr@2:         }
williamr@2:         put(color, u, Color::black());
williamr@2:         vis.finish_vertex(u, g);
williamr@2:       }
williamr@2:     }
williamr@2: 
williamr@2: #else // BOOST_RECURSIVE_DFS is defined
williamr@2: 
williamr@2:     template <class IncidenceGraph, class DFSVisitor, class ColorMap,
williamr@2:               class TerminatorFunc>
williamr@2:     void depth_first_visit_impl
williamr@2:       (const IncidenceGraph& g,
williamr@2:        typename graph_traits<IncidenceGraph>::vertex_descriptor u,
williamr@2:        DFSVisitor& vis,  // pass-by-reference here, important!
williamr@2:        ColorMap color, TerminatorFunc func)
williamr@2:     {
williamr@2:       function_requires<IncidenceGraphConcept<IncidenceGraph> >();
williamr@2:       function_requires<DFSVisitorConcept<DFSVisitor, IncidenceGraph> >();
williamr@2:       typedef typename graph_traits<IncidenceGraph>::vertex_descriptor Vertex;
williamr@2:       function_requires< ReadWritePropertyMapConcept<ColorMap, Vertex> >();
williamr@2:       typedef typename property_traits<ColorMap>::value_type ColorValue;
williamr@2:       function_requires< ColorValueConcept<ColorValue> >();
williamr@2:       typedef color_traits<ColorValue> Color;
williamr@2:       typename graph_traits<IncidenceGraph>::out_edge_iterator ei, ei_end;
williamr@2: 
williamr@2:       put(color, u, Color::gray());          vis.discover_vertex(u, g);
williamr@2: 
williamr@2:       typedef typename unwrap_reference<TerminatorFunc>::type TF;
williamr@2:       // Variable is needed to workaround a borland bug.
williamr@2:       TF& fn = static_cast<TF&>(func);
williamr@2:       if (!fn(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:           depth_first_visit_impl(g, v, vis, color, func);
williamr@2:           } else if (v_color == Color::gray()) vis.back_edge(*ei, g);
williamr@2:           else                                 vis.forward_or_cross_edge(*ei, g);
williamr@2:         }
williamr@2:       put(color, u, Color::black());         vis.finish_vertex(u, g);
williamr@2:     }
williamr@2: 
williamr@2: #endif
williamr@2: 
williamr@2:   } // namespace detail
williamr@2: 
williamr@2:   template <class VertexListGraph, class DFSVisitor, class ColorMap>
williamr@2:   void
williamr@2:   depth_first_search(const VertexListGraph& g, DFSVisitor vis, ColorMap color,
williamr@2:                      typename graph_traits<VertexListGraph>::vertex_descriptor start_vertex)
williamr@2:   {
williamr@2:     typedef typename graph_traits<VertexListGraph>::vertex_descriptor Vertex;
williamr@2:     function_requires<DFSVisitorConcept<DFSVisitor, VertexListGraph> >();
williamr@2:     typedef typename property_traits<ColorMap>::value_type ColorValue;
williamr@2:     typedef color_traits<ColorValue> Color;
williamr@2: 
williamr@2:     typename graph_traits<VertexListGraph>::vertex_iterator ui, ui_end;
williamr@2:     for (tie(ui, ui_end) = vertices(g); ui != ui_end; ++ui) {
williamr@2:       put(color, *ui, Color::white());       vis.initialize_vertex(*ui, g);
williamr@2:     }
williamr@2: 
williamr@2:     if (start_vertex != implicit_cast<Vertex>(*vertices(g).first)){ vis.start_vertex(start_vertex, g);
williamr@2:       detail::depth_first_visit_impl(g, start_vertex, vis, color,
williamr@2:                                      detail::nontruth2());
williamr@2:     }
williamr@2: 
williamr@2:     for (tie(ui, ui_end) = vertices(g); ui != ui_end; ++ui) {
williamr@2:       ColorValue u_color = get(color, *ui);
williamr@2:       if (u_color == Color::white()) {       vis.start_vertex(*ui, g);
williamr@2:         detail::depth_first_visit_impl(g, *ui, vis, color, detail::nontruth2());
williamr@2:       }
williamr@2:     }
williamr@2:   }
williamr@2: 
williamr@2:   template <class VertexListGraph, class DFSVisitor, class ColorMap>
williamr@2:   void
williamr@2:   depth_first_search(const VertexListGraph& g, DFSVisitor vis, ColorMap color)
williamr@2:   {
williamr@2:     if (vertices(g).first == vertices(g).second)
williamr@2:       return;
williamr@2: 
williamr@2:     depth_first_search(g, vis, color, *vertices(g).first);
williamr@2:   }
williamr@2: 
williamr@2:   namespace detail {
williamr@2:     template <class ColorMap>
williamr@2:     struct dfs_dispatch {
williamr@2: 
williamr@2:       template <class VertexListGraph, class Vertex, class DFSVisitor,
williamr@2:                 class P, class T, class R>
williamr@2:       static void
williamr@2:       apply(const VertexListGraph& g, DFSVisitor vis, Vertex start_vertex,
williamr@2:             const bgl_named_params<P, T, R>&,
williamr@2:             ColorMap color)
williamr@2:       {
williamr@2:         depth_first_search(g, vis, color, start_vertex);
williamr@2:       }
williamr@2:     };
williamr@2: 
williamr@2:     template <>
williamr@2:     struct dfs_dispatch<detail::error_property_not_found> {
williamr@2:       template <class VertexListGraph, class Vertex, class DFSVisitor,
williamr@2:                 class P, class T, class R>
williamr@2:       static void
williamr@2:       apply(const VertexListGraph& g, DFSVisitor vis, Vertex start_vertex,
williamr@2:             const bgl_named_params<P, T, R>& params,
williamr@2:             detail::error_property_not_found)
williamr@2:       {
williamr@2:         std::vector<default_color_type> color_vec(num_vertices(g));
williamr@2:         default_color_type c = white_color; // avoid warning about un-init
williamr@2:         depth_first_search
williamr@2:           (g, vis, 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:            start_vertex);
williamr@2:       }
williamr@2:     };
williamr@2:   } // namespace detail
williamr@2: 
williamr@2: 
williamr@2:   template <class Visitors = null_visitor>
williamr@2:   class dfs_visitor {
williamr@2:   public:
williamr@2:     dfs_visitor() { }
williamr@2:     dfs_visitor(Visitors vis) : m_vis(vis) { }
williamr@2: 
williamr@2:     template <class Vertex, class Graph>
williamr@2:     void initialize_vertex(Vertex u, const Graph& g) {
williamr@2:       invoke_visitors(m_vis, u, g, ::boost::on_initialize_vertex());
williamr@2:     }
williamr@2:     template <class Vertex, class Graph>
williamr@2:     void start_vertex(Vertex u, const Graph& g) {
williamr@2:       invoke_visitors(m_vis, u, g, ::boost::on_start_vertex());
williamr@2:     }
williamr@2:     template <class Vertex, class Graph>
williamr@2:     void discover_vertex(Vertex u, const Graph& g) {
williamr@2:       invoke_visitors(m_vis, u, g, ::boost::on_discover_vertex());
williamr@2:     }
williamr@2:     template <class Edge, class Graph>
williamr@2:     void examine_edge(Edge u, const Graph& g) {
williamr@2:       invoke_visitors(m_vis, u, g, ::boost::on_examine_edge());
williamr@2:     }
williamr@2:     template <class Edge, class Graph>
williamr@2:     void tree_edge(Edge u, const Graph& g) {
williamr@2:       invoke_visitors(m_vis, u, g, ::boost::on_tree_edge());
williamr@2:     }
williamr@2:     template <class Edge, class Graph>
williamr@2:     void back_edge(Edge u, const Graph& g) {
williamr@2:       invoke_visitors(m_vis, u, g, ::boost::on_back_edge());
williamr@2:     }
williamr@2:     template <class Edge, class Graph>
williamr@2:     void forward_or_cross_edge(Edge u, const Graph& g) {
williamr@2:       invoke_visitors(m_vis, u, g, ::boost::on_forward_or_cross_edge());
williamr@2:     }
williamr@2:     template <class Vertex, class Graph>
williamr@2:     void finish_vertex(Vertex u, const 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,dfs)
williamr@2:     BOOST_GRAPH_EVENT_STUB(on_start_vertex,dfs)
williamr@2:     BOOST_GRAPH_EVENT_STUB(on_discover_vertex,dfs)
williamr@2:     BOOST_GRAPH_EVENT_STUB(on_examine_edge,dfs)
williamr@2:     BOOST_GRAPH_EVENT_STUB(on_tree_edge,dfs)
williamr@2:     BOOST_GRAPH_EVENT_STUB(on_back_edge,dfs)
williamr@2:     BOOST_GRAPH_EVENT_STUB(on_forward_or_cross_edge,dfs)
williamr@2:     BOOST_GRAPH_EVENT_STUB(on_finish_vertex,dfs)
williamr@2: 
williamr@2:   protected:
williamr@2:     Visitors m_vis;
williamr@2:   };
williamr@2:   template <class Visitors>
williamr@2:   dfs_visitor<Visitors>
williamr@2:   make_dfs_visitor(Visitors vis) {
williamr@2:     return dfs_visitor<Visitors>(vis);
williamr@2:   }
williamr@2:   typedef dfs_visitor<> default_dfs_visitor;
williamr@2: 
williamr@2: 
williamr@2:   // Named Parameter Variant
williamr@2:   template <class VertexListGraph, class P, class T, class R>
williamr@2:   void
williamr@2:   depth_first_search(const VertexListGraph& g,
williamr@2:                      const bgl_named_params<P, T, R>& params)
williamr@2:   {
williamr@2:     typedef typename property_value< bgl_named_params<P, T, R>,
williamr@2:       vertex_color_t>::type C;
williamr@2:     if (vertices(g).first == vertices(g).second)
williamr@2:       return;
williamr@2:     detail::dfs_dispatch<C>::apply
williamr@2:       (g,
williamr@2:        choose_param(get_param(params, graph_visitor),
williamr@2:                     make_dfs_visitor(null_visitor())),
williamr@2:        choose_param(get_param(params, root_vertex_t()),
williamr@2:                     *vertices(g).first),
williamr@2:        params,
williamr@2:        get_param(params, vertex_color)
williamr@2:        );
williamr@2:   }
williamr@2: 
williamr@2:   template <class IncidenceGraph, class DFSVisitor, class ColorMap>
williamr@2:   void depth_first_visit
williamr@2:     (const IncidenceGraph& g,
williamr@2:      typename graph_traits<IncidenceGraph>::vertex_descriptor u,
williamr@2:      DFSVisitor vis, ColorMap color)
williamr@2:   {
williamr@2:     vis.start_vertex(u, g);
williamr@2:     detail::depth_first_visit_impl(g, u, vis, color, detail::nontruth2());
williamr@2:   }
williamr@2: 
williamr@2:   template <class IncidenceGraph, class DFSVisitor, class ColorMap,
williamr@2:             class TerminatorFunc>
williamr@2:   void depth_first_visit
williamr@2:     (const IncidenceGraph& g,
williamr@2:      typename graph_traits<IncidenceGraph>::vertex_descriptor u,
williamr@2:      DFSVisitor vis, ColorMap color, TerminatorFunc func = TerminatorFunc())
williamr@2:   {
williamr@2:     vis.start_vertex(u, g);
williamr@2:     detail::depth_first_visit_impl(g, u, vis, color, func);
williamr@2:   }
williamr@2: 
williamr@2: 
williamr@2: } // namespace boost
williamr@2: 
williamr@2: 
williamr@2: #endif