/Src/Dependencies/Boost/boost/graph/property_maps/null_property_map.hpp
http://hadesmem.googlecode.com/ · C++ Header · 41 lines · 21 code · 8 blank · 12 comment · 0 complexity · 0690499e7955d3f4e590d70b3a137283 MD5 · raw file
- // (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_NULL_PROPERTY_HPP
- #define BOOST_GRAPH_NULL_PROPERTY_HPP
- #include <boost/property_map/property_map.hpp>
- // TODO: This should really be part of the property maps library rather than
- // the Boost.Graph library.
- namespace boost
- {
- // A null property is somewhat like the inverse of the constant
- // property map except that instead of returning a single value,
- // this eats any writes and cannot be read from.
- template <typename Key, typename Value>
- struct null_property_map
- {
- typedef Key key_type;
- typedef Value value_type;
- typedef void reference;
- typedef boost::writable_property_map_tag category;
- };
- // The null_property_map<K,V> only has a put() function.
- template <typename K, typename V>
- void put(null_property_map<K,V>& pm, const K& key, const V& value)
- { }
- // A helper function for intantiating null property maps.
- template <typename Key, typename Value>
- inline null_property_map<Key, Value> make_null_property()
- { return null_property_map<Key, Value>(); }
- }
- #endif