Added boost header

test/external/boost/geometry/strategies/cartesian/centroid_weighted_length.hpp

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+// Boost.Geometry (aka GGL, Generic Geometry Library)
+
+// Copyright (c) 2009-2011 Mateusz Loskot, London, UK.
+// Copyright (c) 2009-2011 Barend Gehrels, Amsterdam, the Netherlands.
+
+// 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_CARTESIAN_CENTROID_WEIGHTED_LENGTH_HPP
+#define BOOST_GEOMETRY_STRATEGIES_CARTESIAN_CENTROID_WEIGHTED_LENGTH_HPP
+
+#include <boost/geometry/algorithms/distance.hpp>
+#include <boost/geometry/arithmetic/arithmetic.hpp>
+#include <boost/geometry/util/select_most_precise.hpp>
+#include <boost/geometry/strategies/centroid.hpp>
+#include <boost/geometry/strategies/default_distance_result.hpp>
+
+// Helper geometry
+#include <boost/geometry/geometries/point.hpp>
+
+
+namespace boost { namespace geometry
+{
+
+namespace strategy { namespace centroid
+{
+
+namespace detail
+{
+
+template <typename Type, std::size_t DimensionCount>
+struct weighted_length_sums
+{
+    typedef typename geometry::model::point
+        <
+            Type, DimensionCount,
+            cs::cartesian
+        > work_point;
+
+    Type length;
+    work_point average_sum;
+
+    inline weighted_length_sums()
+        : length(Type())
+    {
+        geometry::assign_zero(average_sum);
+    }
+};
+}
+
+template
+<
+    typename Point,
+    typename PointOfSegment = Point
+>
+class weighted_length
+{
+private :
+    typedef typename select_most_precise
+        <
+            typename default_distance_result<Point>::type,
+            typename default_distance_result<PointOfSegment>::type
+        >::type distance_type;
+
+public :
+    typedef detail::weighted_length_sums
+        <
+            distance_type,
+            geometry::dimension<Point>::type::value
+        > state_type;
+
+    static inline void apply(PointOfSegment const& p1,
+            PointOfSegment const& p2, state_type& state)
+    {
+        distance_type const d = geometry::distance(p1, p2);
+        state.length += d;
+
+        typename state_type::work_point weighted_median;
+        geometry::assign_zero(weighted_median);
+        geometry::add_point(weighted_median, p1);
+        geometry::add_point(weighted_median, p2);
+        geometry::multiply_value(weighted_median, d/2);
+        geometry::add_point(state.average_sum, weighted_median);
+    }
+
+    static inline bool result(state_type const& state, Point& centroid)
+    {
+        distance_type const zero = distance_type();
+        if (! geometry::math::equals(state.length, zero))
+        {
+            assign_zero(centroid);
+            add_point(centroid, state.average_sum);
+            divide_value(centroid, state.length);
+            return true;
+        }
+
+        return false;
+    }
+
+};
+
+#ifndef DOXYGEN_NO_STRATEGY_SPECIALIZATIONS
+
+namespace services
+{
+
+
+// Register this strategy for linear geometries, in all dimensions
+
+template <std::size_t N, typename Point, typename Geometry>
+struct default_strategy
+<
+    cartesian_tag,
+    linear_tag,
+    N,
+    Point,
+    Geometry
+>
+{
+    typedef weighted_length
+        <
+            Point,
+            typename point_type<Geometry>::type
+        > type;
+};
+
+
+} // namespace services
+
+
+#endif // DOXYGEN_NO_STRATEGY_SPECIALIZATIONS
+
+
+}} // namespace strategy::centroid
+
+
+}} // namespace boost::geometry
+
+
+#endif // BOOST_GEOMETRY_STRATEGIES_CARTESIAN_CENTROID_WEIGHTED_LENGTH_HPP