Added boost header

test/external/boost/geometry/strategies/spherical/compare_circular.hpp

@@ -0,0 +1,152 @@
+// Boost.Geometry (aka GGL, Generic Geometry Library)
+
+// Copyright (c) 2007-2011 Barend Gehrels, 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_SPHERICAL_COMPARE_SPHERICAL_HPP
+#define BOOST_GEOMETRY_STRATEGIES_SPHERICAL_COMPARE_SPHERICAL_HPP
+
+#include <boost/math/constants/constants.hpp>
+
+#include <boost/geometry/core/cs.hpp>
+#include <boost/geometry/core/tags.hpp>
+#include <boost/geometry/strategies/compare.hpp>
+#include <boost/geometry/util/math.hpp>
+
+
+namespace boost { namespace geometry
+{
+
+
+namespace strategy { namespace compare
+{
+
+
+#ifndef DOXYGEN_NO_DETAIL
+namespace detail
+{
+
+template <typename Units>
+struct shift
+{
+};
+
+template <>
+struct shift<degree>
+{
+    static inline double full() { return 360.0; }
+    static inline double half() { return 180.0; }
+};
+
+template <>
+struct shift<radian>
+{
+    static inline double full() { return 2.0 * boost::math::constants::pi<double>(); }
+    static inline double half() { return boost::math::constants::pi<double>(); }
+};
+
+} // namespace detail
+#endif
+
+/*!
+\brief Compare (in one direction) strategy for spherical coordinates
+\ingroup strategies
+\tparam Point point-type
+\tparam Dimension dimension
+*/
+template <typename CoordinateType, typename Units, typename Compare>
+struct circular_comparator
+{
+    static inline CoordinateType put_in_range(CoordinateType const& c,
+            double min_border, double max_border)
+    {
+        CoordinateType value = c;
+        while (value < min_border)
+        {
+            value += detail::shift<Units>::full();
+        }
+        while (value > max_border)
+        {
+            value -= detail::shift<Units>::full();
+        }
+        return value;
+    }
+
+    inline bool operator()(CoordinateType const& c1, CoordinateType const& c2)  const
+    {
+        Compare compare;
+
+        // Check situation that one of them is e.g. std::numeric_limits.
+        static const double full = detail::shift<Units>::full();
+        double mx = 10.0 * full;
+        if (c1 < -mx || c1 > mx || c2 < -mx || c2 > mx)
+        {
+            // do normal comparison, using circular is not useful
+            return compare(c1, c2);
+        }
+
+        static const double half = full / 2.0;
+        CoordinateType v1 = put_in_range(c1, -half, half);
+        CoordinateType v2 = put_in_range(c2, -half, half);
+
+        // Two coordinates on a circle are
+        // at max <= half a circle away from each other.
+        // So if it is more, shift origin.
+        CoordinateType diff = geometry::math::abs(v1 - v2);
+        if (diff > half)
+        {
+            v1 = put_in_range(v1, 0, full);
+            v2 = put_in_range(v2, 0, full);
+        }
+
+        return compare(v1, v2);
+    }
+};
+
+}} // namespace strategy::compare
+
+#ifndef DOXYGEN_NO_STRATEGY_SPECIALIZATIONS
+
+// Specialize for the longitude (dim 0)
+template
+<
+    typename Point,
+    template<typename> class CoordinateSystem,
+    typename Units
+>
+struct strategy_compare<spherical_polar_tag, 1, Point, CoordinateSystem<Units>, 0>
+{
+    typedef typename coordinate_type<Point>::type coordinate_type;
+    typedef strategy::compare::circular_comparator
+        <
+            coordinate_type,
+            Units,
+            std::less<coordinate_type>
+        > type;
+};
+
+template
+<
+    typename Point,
+    template<typename> class CoordinateSystem,
+    typename Units
+>
+struct strategy_compare<spherical_polar_tag, -1, Point, CoordinateSystem<Units>, 0>
+{
+    typedef typename coordinate_type<Point>::type coordinate_type;
+    typedef strategy::compare::circular_comparator
+        <
+            coordinate_type,
+            Units,
+            std::greater<coordinate_type>
+        > type;
+};
+
+#endif // DOXYGEN_NO_STRATEGY_SPECIALIZATIONS
+
+}} // namespace boost::geometry
+
+#endif // BOOST_GEOMETRY_STRATEGIES_SPHERICAL_COMPARE_SPHERICAL_HPP