//
|
//=======================================================================
|
// 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_TOPOLOGICAL_SORT_HPP
|
#define BOOST_GRAPH_TOPOLOGICAL_SORT_HPP
|
|
#include <boost/config.hpp>
|
#include <boost/property_map/property_map.hpp>
|
#include <boost/graph/depth_first_search.hpp>
|
#include <boost/graph/visitors.hpp>
|
#include <boost/graph/exception.hpp>
|
#include <boost/throw_exception.hpp>
|
|
namespace boost
|
{
|
|
// Topological sort visitor
|
//
|
// This visitor merely writes the linear ordering into an
|
// OutputIterator. The OutputIterator could be something like an
|
// ostream_iterator, or it could be a back/front_insert_iterator.
|
// Note that if it is a back_insert_iterator, the recorded order is
|
// the reverse topological order. On the other hand, if it is a
|
// front_insert_iterator, the recorded order is the topological
|
// order.
|
//
|
template < typename OutputIterator >
|
struct topo_sort_visitor : public dfs_visitor<>
|
{
|
topo_sort_visitor(OutputIterator _iter) : m_iter(_iter) {}
|
|
template < typename Edge, typename Graph >
|
void back_edge(const Edge&, Graph&)
|
{
|
BOOST_THROW_EXCEPTION(not_a_dag());
|
}
|
|
template < typename Vertex, typename Graph >
|
void finish_vertex(const Vertex& u, Graph&)
|
{
|
*m_iter++ = u;
|
}
|
|
OutputIterator m_iter;
|
};
|
|
// Topological Sort
|
//
|
// The topological sort algorithm creates a linear ordering
|
// of the vertices such that if edge (u,v) appears in the graph,
|
// then u comes before v in the ordering. The graph must
|
// be a directed acyclic graph (DAG). The implementation
|
// consists mainly of a call to depth-first search.
|
//
|
|
template < typename VertexListGraph, typename OutputIterator, typename P,
|
typename T, typename R >
|
void topological_sort(VertexListGraph& g, OutputIterator result,
|
const bgl_named_params< P, T, R >& params)
|
{
|
typedef topo_sort_visitor< OutputIterator > TopoVisitor;
|
depth_first_search(g, params.visitor(TopoVisitor(result)));
|
}
|
|
template < typename VertexListGraph, typename OutputIterator >
|
void topological_sort(VertexListGraph& g, OutputIterator result)
|
{
|
topological_sort(
|
g, result, bgl_named_params< int, buffer_param_t >(0)); // bogus
|
}
|
|
} // namespace boost
|
|
#endif /*BOOST_GRAPH_TOPOLOGICAL_SORT_H*/
|
