Chris@16: // (C) Copyright 2007-2009 Andrew Sutton
Chris@16: //
Chris@16: // Use, modification and distribution are subject to the
Chris@16: // Boost Software License, Version 1.0 (See accompanying file
Chris@16: // LICENSE_1_0.txt or http://www.boost.org/LICENSE_1_0.txt)
Chris@16: 
Chris@16: #ifndef BOOST_GRAPH_MATRIX_PROPERTY_MAP_HPP
Chris@16: #define BOOST_GRAPH_MATRIX_PROPERTY_MAP_HPP
Chris@16: 
Chris@16: #include <boost/graph/property_maps/container_property_map.hpp>
Chris@16: 
Chris@16: namespace boost
Chris@16: {
Chris@16:     // This property map is built specifically for property maps over
Chris@16:     // matrices. Like the basic property map over a container, this builds
Chris@16:     // the property abstraction over a matrix (usually a vector of vectors)
Chris@16:     // and returns property maps over the nested containers.
Chris@16:     template <typename Graph, typename Key, typename Matrix>
Chris@16:     struct matrix_property_map
Chris@16:         : boost::put_get_helper<
Chris@16:                 container_property_map<Graph, Key, typename Matrix::value_type>,
Chris@16:                 matrix_property_map<Graph, Key, Matrix> >
Chris@16:     {
Chris@16:         // abstract the indexing keys
Chris@16:         typedef typename detail::choose_indexer<Graph, Key>::indexer_type indexer_type;
Chris@16: 
Chris@16:         // aliases for the nested container and its corresponding map
Chris@16:         typedef typename Matrix::value_type container_type;
Chris@16:         typedef container_property_map<Graph, Key, container_type> map_type;
Chris@16: 
Chris@16:         typedef Key key_type;
Chris@16: 
Chris@16:         // This property map doesn't really provide access to nested containers,
Chris@16:         // but returns property maps over them. Since property maps are all
Chris@16:         // copy-constructible (or should be anyways), we never return references.
Chris@16:         // As such, this property is only readable, but not writable. Curiously,
Chris@16:         // the inner property map is actually an lvalue pmap.
Chris@16:         typedef map_type value_type;
Chris@16:         typedef map_type reference;
Chris@16:         typedef readable_property_map_tag category;
Chris@16: 
Chris@16:         matrix_property_map()
Chris@16:             : m_matrix(0), m_graph(0)
Chris@16:         { }
Chris@16: 
Chris@16:         matrix_property_map(Matrix& m, const Graph& g)
Chris@16:             : m_matrix(&m), m_graph(const_cast<Graph*>(&g))
Chris@16:         { }
Chris@16: 
Chris@16:         matrix_property_map(const matrix_property_map& x)
Chris@16:             : m_matrix(x.m_matrix), m_graph(x.m_graph)
Chris@16:         { }
Chris@16: 
Chris@16:         inline reference operator [](key_type k) const
Chris@16:         {
Chris@16:             typedef typename indexer_type::value_type Index;
Chris@16:             Index x = indexer_type::index(k, *m_graph);
Chris@16:             return map_type((*m_matrix)[x], *m_graph);
Chris@16:         }
Chris@16: 
Chris@16:     private:
Chris@16:         mutable Matrix* m_matrix;
Chris@16:         mutable Graph* m_graph;
Chris@16:     };
Chris@16: }
Chris@16: 
Chris@16: #endif