Added thirdparty: boost library

thirdparty/include/boost/graph/property_maps/constant_property_map.hpp

@@ -0,0 +1,89 @@
+// (C) Copyright 2007-2009 Andrew Sutton
+//
+// 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_CONSTANT_PROPERTY_HPP
+#define BOOST_GRAPH_CONSTANT_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 constant property is one, that regardless of the edge or vertex given,
+ * will always return a constant value.
+ */
+template < typename Key, typename Value >
+struct constant_property_map : public boost::put_get_helper< const Value&,
+                                   constant_property_map< Key, Value > >
+{
+    typedef Key key_type;
+    typedef Value value_type;
+    typedef const Value& reference;
+    typedef boost::readable_property_map_tag category;
+
+    constant_property_map() : m_value() {}
+
+    constant_property_map(const value_type& value) : m_value(value) {}
+
+    constant_property_map(const constant_property_map& copy)
+    : m_value(copy.m_value)
+    {
+    }
+
+    inline reference operator[](const key_type&) const { return m_value; }
+
+    value_type m_value;
+};
+
+template < typename Key, typename Value >
+inline constant_property_map< Key, Value > make_constant_property(
+    const Value& value)
+{
+    return constant_property_map< Key, Value >(value);
+}
+
+/**
+ * Same as above, but pretends to be writable as well.
+ */
+template < typename Key, typename Value > struct constant_writable_property_map
+{
+    typedef Key key_type;
+    typedef Value value_type;
+    typedef Value& reference;
+    typedef boost::read_write_property_map_tag category;
+
+    constant_writable_property_map() : m_value() {}
+
+    constant_writable_property_map(const value_type& value) : m_value(value) {}
+
+    constant_writable_property_map(const constant_writable_property_map& copy)
+    : m_value(copy.m_value)
+    {
+    }
+
+    friend Value get(const constant_writable_property_map& me, Key)
+    {
+        return me.m_value;
+    }
+    friend void put(const constant_writable_property_map&, Key, Value) {}
+
+    value_type m_value;
+};
+
+template < typename Key, typename Value >
+inline constant_writable_property_map< Key, Value >
+make_constant_writable_property(const Value& value)
+{
+    return constant_writable_property_map< Key, Value >(value);
+}
+
+} /* namespace boost */
+
+#endif