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// Copyright 2008-2010 Gordon Woodhull
// 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_MSM_MPL_GRAPH_BREADTH_FIRST_SEARCH_HPP_INCLUDED
#define BOOST_MSM_MPL_GRAPH_BREADTH_FIRST_SEARCH_HPP_INCLUDED
#include <boost/msm/mpl_graph/mpl_graph.hpp>
#include <boost/mpl/has_key.hpp>
#include <boost/mpl/insert.hpp>
#include <boost/mpl/pair.hpp>
#include <boost/mpl/map.hpp>
#include <boost/mpl/has_key.hpp>
#include <boost/mpl/pop_front.hpp>
#include <boost/mpl/empty.hpp>
#include <boost/mpl/remove.hpp>
#include "search_colors.hpp"
namespace boost {
namespace msm {
namespace mpl_graph {
// bfs takes a visitor which has all the bgl-like metafunctions encapsulated in an
// "operations" member class, and also a state. the operations are expected to return a new state
struct bfs_default_visitor_operations {
template<typename Vertex, typename Graph, typename State>
struct initialize_vertex {
typedef State type;
};
template<typename Vertex, typename Graph, typename State>
struct discover_vertex {
typedef State type;
};
template<typename Vertex, typename Graph, typename State>
struct examine_vertex {
typedef State type;
};
template<typename Vertex, typename Graph, typename State>
struct examine_edge {
typedef State type;
};
template<typename Edge, typename Graph, typename State>
struct tree_edge {
typedef State type;
};
template<typename Edge, typename Graph, typename State>
struct non_tree_edge {
typedef State type;
};
template<typename Edge, typename Graph, typename State>
struct gray_target {
typedef State type;
};
template<typename Edge, typename Graph, typename State>
struct black_target {
typedef State type;
};
template<typename Vertex, typename Graph, typename State>
struct finish_vertex {
typedef State type;
};
};
namespace detail {
template<typename Graph, typename VisitorOps, typename VCQState, typename Edge>
struct bfs_run_queue_examine_edge {
typedef typename VisitorOps::template examine_edge<Edge, Graph, typename mpl::at_c<VCQState, 0>::type>::type visitor_state;
typedef typename mpl::at_c<VCQState, 1>::type color_state;
typedef typename mpl::at_c<VCQState, 2>::type vertex_queue;
typedef typename mpl::if_<typename boost::is_same<typename search_color_map_ops::template get_color<typename mpl_graph::target<Edge, Graph>::type, color_state>::type, search_colors::White>::type,
// unseen target: tree edge, discover target, paint it gray, and enqueue
mpl::vector<typename VisitorOps::template discover_vertex<typename mpl_graph::target<Edge, Graph>::type, Graph,
typename VisitorOps::template tree_edge<Edge, Graph, visitor_state>::type>::type,
typename search_color_map_ops::template set_color<typename mpl_graph::target<Edge, Graph>::type, search_colors::Gray, color_state>::type,
typename mpl::push_back<vertex_queue, typename mpl_graph::target<Edge, Graph>::type >::type >,
// seen
mpl::vector<typename mpl::if_<typename boost::is_same<typename search_color_map_ops::template get_color<mpl_graph::target<Edge, Graph>, color_state>,
search_colors::Gray>::type,
typename VisitorOps::template gray_target<Edge, Graph, visitor_state>::type,
typename VisitorOps::template black_target<Edge, Graph, visitor_state>::type>::type,
color_state,
vertex_queue>
>::type type;
};
// runs bfs on a queue, passing the new queue forward on recursion
// returns pair<visitor_state, color_state>
template<typename Graph, typename VertexQueue, typename VisitorOps, typename VisitorState, typename ColorMap>
struct bfs_run_queue {
// enter vertex
typedef typename mpl::front<VertexQueue>::type Vertex;
typedef typename mpl::pop_front<VertexQueue>::type Tail;
typedef typename VisitorOps::template examine_vertex<Vertex, Graph, VisitorState>::type examined_state;
// loop over out edges
typedef typename mpl::template
fold<typename mpl_graph::out_edges<Vertex, Graph>::type,
mpl::vector<examined_state, ColorMap, Tail>,
bfs_run_queue_examine_edge<Graph, VisitorOps, mpl::_1, mpl::_2>
>::type did_edges;
typedef typename VisitorOps::template
finish_vertex<Vertex, Graph, typename mpl::at_c<did_edges, 0>::type>::type
finished_vertex;
// does map insert always overwrite? i seem to remember this not working on msvc once
typedef typename search_color_map_ops::template
set_color<Vertex, search_colors::Black, typename mpl::at_c<did_edges, 1>::type>::type
colored_vertex;
typedef typename mpl::at_c<did_edges, 2>::type queued_targets;
typedef typename
mpl::if_<typename mpl::empty<queued_targets>::type,
mpl::pair<finished_vertex, colored_vertex>,
bfs_run_queue<Graph, queued_targets,
VisitorOps, finished_vertex,
colored_vertex> >::type::type type;
};
} // namespace detail
template<typename Graph, typename VisitorOps, typename VisitorState,
typename Vertex,
typename ColorMap = create_search_color_map::type >
struct breadth_first_search {
typedef typename VisitorOps::template
discover_vertex<Vertex, Graph, VisitorState>::type
discovered_state;
typedef typename search_color_map_ops::template
set_color<Vertex, search_colors::Gray, ColorMap>::type
discovered_colors;
typedef typename detail::
bfs_run_queue<Graph, mpl::vector<Vertex>,
VisitorOps, discovered_state,
discovered_colors>::type type;
};
template<typename Graph, typename VisitorOps, typename VisitorState,
typename FirstVertex = typename mpl::front<typename mpl_graph::vertices<Graph>::type>::type,
typename ColorMap = create_search_color_map::type>
struct breadth_first_search_all : // visit "first" first, then visit any still white
mpl::fold<typename mpl_graph::vertices<Graph>::type,
typename breadth_first_search<Graph, VisitorOps, VisitorState, FirstVertex, ColorMap>::type,
mpl::if_<boost::is_same<search_color_map_ops::template get_color<mpl::_2, mpl::second<mpl::_1> >,
search_colors::White>,
breadth_first_search<Graph, VisitorOps, mpl::first<mpl::_1>,
mpl::_2, mpl::second<mpl::_1> >,
mpl::_1> >
{};
} // namespace mpl_graph
} // namespace msm
} // namespace boost
#endif // BOOST_MSM_MPL_GRAPH_BREADTH_FIRST_SEARCH_HPP_INCLUDED