From c5b3acb70cf96aab7652e1a25c697ade82b7c51b Mon Sep 17 00:00:00 2001
From: Samuel Debionne <samuel.debionne@ujf-grenoble.fr>
Date: Wed, 21 May 2014 21:02:53 +0200
Subject: [PATCH] [expand] Add variant support

---
 include/boost/geometry/algorithms/expand.hpp | 48 +++++++++++++++++++-
 test/algorithms/expand.cpp                   |  1 +
 2 files changed, 48 insertions(+), 1 deletion(-)

diff --git a/include/boost/geometry/algorithms/expand.hpp b/include/boost/geometry/algorithms/expand.hpp
index 2e1531bf0..f29fd4a40 100644
--- a/include/boost/geometry/algorithms/expand.hpp
+++ b/include/boost/geometry/algorithms/expand.hpp
@@ -28,6 +28,9 @@
 #include <boost/geometry/strategies/compare.hpp>
 #include <boost/geometry/policies/compare.hpp>
 
+#include <boost/variant/static_visitor.hpp>
+#include <boost/variant/apply_visitor.hpp>
+
 
 namespace boost { namespace geometry
 {
@@ -249,6 +252,49 @@ struct expand<Box, Segment, StrategyLess, StrategyGreater, box_tag, segment_tag>
 #endif // DOXYGEN_NO_DISPATCH
 
 
+namespace resolve_variant {
+    
+template <typename Geometry>
+struct expand
+{
+    template <typename Box>
+    static inline void apply(Box& box, Geometry const& geometry)
+    {
+        concept::check_concepts_and_equal_dimensions<Box, Geometry const>();
+        
+        dispatch::expand<Box, Geometry>::apply(box, geometry);
+    }
+};
+
+template <BOOST_VARIANT_ENUM_PARAMS(typename T)>
+struct expand<boost::variant<BOOST_VARIANT_ENUM_PARAMS(T)> >
+{
+    template <typename Box>
+    struct visitor: boost::static_visitor<void>
+    {
+        Box& m_box;
+        
+        visitor(Box& box) : m_box(box) {}
+        
+        template <typename Geometry>
+        void operator()(Geometry const& geometry) const
+        {
+            return expand<Geometry>::apply(m_box, geometry);
+        }
+    };
+    
+    template <class Box>
+    static inline void
+    apply(Box& box,
+          boost::variant<BOOST_VARIANT_ENUM_PARAMS(T)> const& geometry)
+    {
+        return boost::apply_visitor(visitor<Box>(box), geometry);
+    }
+};
+    
+} // namespace resolve_variant
+    
+    
 /***
 *!
 \brief Expands a box using the extend (envelope) of another geometry (box, point)
@@ -292,7 +338,7 @@ inline void expand(Box& box, Geometry const& geometry)
 {
     concept::check_concepts_and_equal_dimensions<Box, Geometry const>();
 
-    dispatch::expand<Box, Geometry>::apply(box, geometry);
+    resolve_variant::expand<Geometry>::apply(box, geometry);
 }
 
 }} // namespace boost::geometry
diff --git a/test/algorithms/expand.cpp b/test/algorithms/expand.cpp
index 213e0b1d9..a1322b87b 100644
--- a/test/algorithms/expand.cpp
+++ b/test/algorithms/expand.cpp
@@ -21,6 +21,7 @@
 #include <boost/geometry/geometries/adapted/c_array.hpp>
 #include <boost/geometry/geometries/adapted/boost_tuple.hpp>
 #include <boost/geometry/geometries/adapted/std_pair_as_segment.hpp>
+#include <boost/variant/variant.hpp>
 #include <test_common/test_point.hpp>
 
 BOOST_GEOMETRY_REGISTER_C_ARRAY_CS(cs::cartesian)