[Boost-commit] svn:boost r82484 - in trunk: boost/geometry/algorithms libs/geometry/test/algorithms

Subject: [Boost-commit] svn:boost r82484 - in trunk: boost/geometry/algorithms libs/geometry/test/algorithms
From: bruno.lalande_at_[hidden]
Date: 2013-01-13 18:09:28

Author: bruno.lalande
Date: 2013-01-13 18:09:27 EST (Sun, 13 Jan 2013)
New Revision: 82484
URL: http://svn.boost.org/trac/boost/changeset/82484

Log:
Made the length algorithm variant-aware.
Text files modified: 
   trunk/boost/geometry/algorithms/length.hpp          |    86 +++++++++++++++++++++++++++++++++++++-- 
   trunk/libs/geometry/test/algorithms/test_length.hpp |     5 +                                       
   2 files changed, 84 insertions(+), 7 deletions(-)

Modified: trunk/boost/geometry/algorithms/length.hpp
==============================================================================
--- trunk/boost/geometry/algorithms/length.hpp	(original)
+++ trunk/boost/geometry/algorithms/length.hpp	2013-01-13 18:09:27 EST (Sun, 13 Jan 2013)
@@ -18,7 +18,14 @@
 
 #include <boost/range.hpp>
 
+#include <boost/mpl/fold.hpp>
+#include <boost/mpl/greater.hpp>
 #include <boost/mpl/if.hpp>
+#include <boost/mpl/insert.hpp>
+#include <boost/mpl/int.hpp>
+#include <boost/mpl/set.hpp>
+#include <boost/mpl/size.hpp>
+#include <boost/mpl/transform.hpp>
 #include <boost/type_traits.hpp>
 
 #include <boost/geometry/core/cs.hpp>
@@ -33,6 +40,10 @@
 #include <boost/geometry/strategies/distance.hpp>
 #include <boost/geometry/strategies/default_length_result.hpp>
 
+#include <boost/variant/apply_visitor.hpp>
+#include <boost/variant/static_visitor.hpp>
+#include <boost/variant/variant_fwd.hpp>
+
 
 namespace boost { namespace geometry
 {
@@ -136,6 +147,69 @@
 {};
 
 
+template <typename Geometry>
+struct devarianted_length
+{
+    typedef typename default_length_result<Geometry>::type result_type;
+
+    template <typename Strategy>
+    static inline result_type apply(Geometry const& geometry,
+                                    Strategy const& strategy)
+    {
+        return length<Geometry>::apply(geometry, strategy);
+    }
+};
+
+template <BOOST_VARIANT_ENUM_PARAMS(typename T)>
+struct devarianted_length<variant<BOOST_VARIANT_ENUM_PARAMS(T)> >
+{
+    typedef typename mpl::fold<
+                typename mpl::transform<
+                    typename variant<BOOST_VARIANT_ENUM_PARAMS(T)>::types,
+                    default_length_result<mpl::_>
+                >::type,
+                mpl::set0<>,
+                mpl::insert<mpl::_1, mpl::_2>
+            >::type possible_result_types;
+
+    typedef typename mpl::if_<
+                mpl::greater<
+                    mpl::size<possible_result_types>,
+                    mpl::int_<1>
+                >,
+                typename make_variant_over<possible_result_types>::type,
+                typename mpl::front<possible_result_types>::type
+            >::type result_type;
+
+    template <typename Strategy>
+    struct visitor
+        : static_visitor<result_type>
+    {
+        Strategy const& m_strategy;
+
+        visitor(Strategy const& strategy)
+            : m_strategy(strategy)
+        {}
+
+        template <typename Geometry>
+        inline typename devarianted_length<Geometry>::result_type
+        operator()(Geometry const& geometry) const
+        {
+            return devarianted_length<Geometry>::apply(geometry, m_strategy);
+        }
+    };
+
+    template <typename Strategy>
+    static inline result_type apply(
+        variant<BOOST_VARIANT_ENUM_PARAMS(T)> const& geometry,
+        Strategy const& strategy
+    )
+    {
+        return apply_visitor(visitor<Strategy>(strategy), geometry);
+    }
+};
+
+
 } // namespace dispatch
 #endif // DOXYGEN_NO_DISPATCH
 
@@ -152,8 +226,8 @@
 \qbk{[length] [length_output]}
  */
 template<typename Geometry>
-inline typename default_length_result<Geometry>::type length(
-        Geometry const& geometry)
+inline typename dispatch::devarianted_length<Geometry>::result_type
+length(Geometry const& geometry)
 {
     concept::check<Geometry const>();
 
@@ -164,7 +238,7 @@
             point_tag, typename point_type<Geometry>::type
         >::type strategy_type;
 
-    return dispatch::length<Geometry>::apply(geometry, strategy_type());
+    return dispatch::devarianted_length<Geometry>::apply(geometry, strategy_type());
 }
 
 
@@ -183,14 +257,14 @@
 \qbk{[length_with_strategy] [length_with_strategy_output]}
  */
 template<typename Geometry, typename Strategy>
-inline typename default_length_result<Geometry>::type length(
-        Geometry const& geometry, Strategy const& strategy)
+inline typename dispatch::devarianted_length<Geometry>::result_type
+length(Geometry const& geometry, Strategy const& strategy)
 {
     concept::check<Geometry const>();
 
     // detail::throw_on_empty_input(geometry);
     
-    return dispatch::length<Geometry>::apply(geometry, strategy);
+    return dispatch::devarianted_length<Geometry>::apply(geometry, strategy);
 }
 
 

Modified: trunk/libs/geometry/test/algorithms/test_length.hpp
==============================================================================
--- trunk/libs/geometry/test/algorithms/test_length.hpp	(original)
+++ trunk/libs/geometry/test/algorithms/test_length.hpp	2013-01-13 18:09:27 EST (Sun, 13 Jan 2013)
@@ -14,12 +14,14 @@
 #include <boost/geometry/algorithms/length.hpp>
 #include <boost/geometry/io/wkt/read.hpp>
 #include <boost/geometry/strategies/strategies.hpp>
+#include <boost/typeof/typeof.hpp>
+#include <boost/variant/variant.hpp>
 
 
 template <typename Geometry>
 void test_length(Geometry const& geometry, long double expected_length)
 {
-    typename bg::default_length_result<Geometry>::type length = bg::length(geometry);
+    BOOST_AUTO(length, bg::length(geometry));
 
 #ifdef GEOMETRY_TEST_DEBUG
     std::ostringstream out;
@@ -42,6 +44,7 @@
     Geometry geometry;
     bg::read_wkt(wkt, geometry);
     test_length(geometry, expected_length);
+    test_length(boost::variant<Geometry>(geometry), expected_length);
 }
 
 template <typename Geometry>