[Boost-commit] svn:boost r38600 - sandbox/SOC/2007/graphs/boost/graph

From: asutton_at_[hidden]
Date: 2007-08-11 11:50:35

Author: asutton
Date: 2007-08-11 11:50:34 EDT (Sat, 11 Aug 2007)
New Revision: 38600
URL: http://svn.boost.org/trac/boost/changeset/38600

Log:
Added a matrix property map as an abstract property map over
other containers

Added:
   sandbox/SOC/2007/graphs/boost/graph/matrix_property_map.hpp   (contents, props changed)

Added: sandbox/SOC/2007/graphs/boost/graph/matrix_property_map.hpp
==============================================================================
--- (empty file)
+++ sandbox/SOC/2007/graphs/boost/graph/matrix_property_map.hpp	2007-08-11 11:50:34 EDT (Sat, 11 Aug 2007)
@@ -0,0 +1,67 @@
+// (C) Copyright Andrew Sutton 2007
+//
+// Use, modification and distribution are subject to the
+// Boost Software License, Version 1.0 (See accompanying file
+// LICENSE_1_0.txt or http://www.boost.org/LICENSE_1_0.txt)
+
+#ifndef BOOST_GRAPH_MATRIX_PROPERTY_MAP_HXX
+#define BOOST_GRAPH_MATRIX_PROPERTY_MAP_HXX
+
+#include <boost/graph/container_property_map.hpp>
+
+namespace boost
+{
+    // This property map is built specifically for property maps over
+    // matrices. Like the basic property map over a container, this builds
+    // the property abstraction over a matrix (usually a vector of vectors)
+    // and returns property maps over the nested containers.
+    template <typename Graph, typename Key, typename Matrix>
+    struct matrix_property_map
+        : boost::put_get_helper<
+                container_property_map<Graph, Key, typename Matrix::value_type>,
+                matrix_property_map<Graph, Key, Matrix> >
+    {
+        // abstract the indexing keys
+        typedef typename detail::choose_indexer<Graph, Key>::indexer_type indexer_type;
+
+        // aliases for the nested container and its corresponding map
+        typedef typename Matrix::value_type container_type;
+        typedef container_property_map<Graph, Key, container_type> map_type;
+
+        typedef Key key_type;
+
+        // This property map doesn't really provide access to nested containers,
+        // but returns property maps over them. Since property maps are all
+        // copy-constructible (or should be anyways), we never return references.
+        // As such, this property is only readable, but not writable. Curiously,
+        // the inner property map is actually an lvalue pmap.
+        typedef map_type value_type;
+        typedef map_type reference;
+        typedef readable_property_map_tag category;
+
+        matrix_property_map()
+            : m_matrix(0), m_graph(0)
+        { }
+
+        matrix_property_map(Matrix& m, const Graph& g)
+            : m_matrix(&m), m_graph(const_cast<Graph*>(&g))
+        { }
+
+        matrix_property_map(const matrix_property_map& x)
+            : m_matrix(x.m_matrix), m_graph(x.m_graph)
+        { }
+
+        inline reference operator [](key_type k) const
+        {
+            typedef typename indexer_type::value_type Index;
+            Index x = indexer_type::index(k, *m_graph);
+            return map_type((*m_matrix)[x], *m_graph);
+        }
+
+    private:
+        mutable Matrix* m_matrix;
+        mutable Graph* m_graph;
+    };
+}
+
+#endif