[distance] perform reverse-dispatch for default strategy

include/boost/geometry/algorithms/detail/distance/default_strategies.hpp

@@ -25,6 +25,7 @@
 #include <boost/geometry/core/tag_cast.hpp>
 #include <boost/geometry/core/tags.hpp>
 #include <boost/geometry/core/point_type.hpp>
+#include <boost/geometry/core/reverse_dispatch.hpp>
 
 #include <boost/geometry/strategies/distance.hpp>
 
@@ -52,7 +53,8 @@ template
     typename Tag2 = typename tag_cast
         <
             typename tag<Geometry2>::type, pointlike_tag
-        >::type
+        >::type,
+    bool Reverse = geometry::reverse_dispatch<Geometry1, Geometry2>::type::value
 >
 struct default_strategy
     : strategy::distance::services::default_strategy
@@ -63,10 +65,24 @@ struct default_strategy
           >
 {};
 
+template
+<
+    typename Geometry1,
+    typename Geometry2,
+    typename Tag1,
+    typename Tag2
+>
+struct default_strategy<Geometry1, Geometry2, Tag1, Tag2, true>
+    : default_strategy<Geometry2, Geometry1, Tag2, Tag1, false>
+{};
+
 
 template <typename Pointlike1, typename Pointlike2>
-struct default_strategy<Pointlike1, Pointlike2, pointlike_tag, pointlike_tag>
-    : strategy::distance::services::default_strategy
+struct default_strategy
+    <
+        Pointlike1, Pointlike2,
+        pointlike_tag, pointlike_tag, false
+    > : strategy::distance::services::default_strategy
           <
               point_tag,
               typename point_type<Pointlike1>::type,
@@ -76,7 +92,7 @@ struct default_strategy<Pointlike1, Pointlike2, pointlike_tag, pointlike_tag>
 
 
 template <typename Pointlike, typename Box>
-struct default_strategy<Pointlike, Box, pointlike_tag, box_tag>
+struct default_strategy<Pointlike, Box, pointlike_tag, box_tag, false>
     : strategy::distance::services::default_strategy
           <
               point_tag,
@@ -91,7 +107,7 @@ struct default_strategy<Pointlike, Box, pointlike_tag, box_tag>
 
 
 template <typename Box1, typename Box2>
-struct default_strategy<Box1, Box2, box_tag, box_tag>
+struct default_strategy<Box1, Box2, box_tag, box_tag, false>
     : strategy::distance::services::default_strategy
           <
               box_tag,

include/boost/geometry/strategies/default_comparable_distance_result.hpp

@@ -0,0 +1,59 @@
+// Boost.Geometry (aka GGL, Generic Geometry Library)
+
+// Copyright (c) 2007-2014 Barend Gehrels, Amsterdam, the Netherlands.
+// Copyright (c) 2008-2014 Bruno Lalande, Paris, France.
+// Copyright (c) 2009-2014 Mateusz Loskot, London, UK.
+
+// This file was modified by Oracle on 2014.
+// Modifications copyright (c) 2014, Oracle and/or its affiliates.
+
+// Contributed and/or modified by Menelaos Karavelas, on behalf of Oracle
+
+// Parts of Boost.Geometry are redesigned from Geodan's Geographic Library
+// (geolib/GGL), copyright (c) 1995-2010 Geodan, Amsterdam, the Netherlands.
+
+// Use, modification and distribution is subject to the Boost Software License,
+// Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt)
+
+#ifndef BOOST_GEOMETRY_STRATEGIES_DEFAULT_COMPARABLE_DISTANCE_RESULT_HPP
+#define BOOST_GEOMETRY_STRATEGIES_DEFAULT_COMPARABLE_DISTANCE_RESULT_HPP
+
+#include <boost/geometry/core/cs.hpp>
+#include <boost/geometry/core/point_type.hpp>
+#include <boost/geometry/strategies/distance.hpp>
+
+
+#include <boost/geometry/algorithms/detail/distance/default_strategies.hpp>
+
+namespace boost { namespace geometry
+{
+
+/*!
+\brief Meta-function defining return type of comparable_distance function
+\ingroup distance
+\note The strategy defines the return-type (so this situation is different
+    from length, where distance is sqr/sqrt, but length always squared)
+ */
+template <typename Geometry1, typename Geometry2 = Geometry1>
+struct default_comparable_distance_result
+{
+    typedef typename strategy::distance::services::return_type
+        <
+            typename strategy::distance::services::comparable_type
+                <
+                    typename detail::distance::default_strategy
+                        <
+                            Geometry1, Geometry2
+                        >::type
+                >::type,
+            typename point_type<Geometry1>::type,
+            typename point_type<Geometry2>::type
+        >::type type;
+};
+
+
+}} // namespace boost::geometry
+
+
+#endif // BOOST_GEOMETRY_STRATEGIES_DEFAULT_COMPARABLE_DISTANCE_RESULT_HPP