ceph/src/boost/boost/graph/property_maps/matrix_property_map.hpp

   1 // (C) Copyright 2007-2009 Andrew Sutton
   2 //
   3 // Use, modification and distribution are subject to the
   4 // Boost Software License, Version 1.0 (See accompanying file
   5 // LICENSE_1_0.txt or http://www.boost.org/LICENSE_1_0.txt)
   6
   7 #ifndef BOOST_GRAPH_MATRIX_PROPERTY_MAP_HPP
   8 #define BOOST_GRAPH_MATRIX_PROPERTY_MAP_HPP
   9
  10 #include <boost/graph/property_maps/container_property_map.hpp>
  11
  12 namespace boost
  13 {
  14     // This property map is built specifically for property maps over
  15     // matrices. Like the basic property map over a container, this builds
  16     // the property abstraction over a matrix (usually a vector of vectors)
  17     // and returns property maps over the nested containers.
  18     template <typename Graph, typename Key, typename Matrix>
  19     struct matrix_property_map
  20         : boost::put_get_helper<
  21                 container_property_map<Graph, Key, typename Matrix::value_type>,
  22                 matrix_property_map<Graph, Key, Matrix> >
  23     {
  24         // abstract the indexing keys
  25         typedef typename detail::choose_indexer<Graph, Key>::indexer_type indexer_type;
  26
  27         // aliases for the nested container and its corresponding map
  28         typedef typename Matrix::value_type container_type;
  29         typedef container_property_map<Graph, Key, container_type> map_type;
  30
  31         typedef Key key_type;
  32
  33         // This property map doesn't really provide access to nested containers,
  34         // but returns property maps over them. Since property maps are all
  35         // copy-constructible (or should be anyways), we never return references.
  36         // As such, this property is only readable, but not writable. Curiously,
  37         // the inner property map is actually an lvalue pmap.
  38         typedef map_type value_type;
  39         typedef map_type reference;
  40         typedef readable_property_map_tag category;
  41
  42         matrix_property_map()
  43             : m_matrix(0), m_graph(0)
  44         { }
  45
  46         matrix_property_map(Matrix& m, const Graph& g)
  47             : m_matrix(&m), m_graph(const_cast<Graph*>(&g))
  48         { }
  49
  50         matrix_property_map(const matrix_property_map& x)
  51             : m_matrix(x.m_matrix), m_graph(x.m_graph)
  52         { }
  53
  54         inline reference operator [](key_type k) const
  55         {
  56             typedef typename indexer_type::value_type Index;
  57             Index x = indexer_type::index(k, *m_graph);
  58             return map_type((*m_matrix)[x], *m_graph);
  59         }
  60
  61     private:
  62         mutable Matrix* m_matrix;
  63         mutable Graph* m_graph;
  64     };
  65 }
  66
  67 #endif