From a3d5fed181a9bf750f740faebf400615014e7703 Mon Sep 17 00:00:00 2001
From: Menelaos Karavelas <menelaos.karavelas@gmail.com>
Date: Mon, 13 Oct 2014 12:16:56 +0300
Subject: [PATCH] [algorithms][distance] add generic implementation for
 distance computation between a linear and a linear/areal geometry

---
 .../distance/linear_or_areal_to_areal.hpp     | 159 ++++++++++++++++++
 1 file changed, 159 insertions(+)
 create mode 100644 include/boost/geometry/algorithms/detail/distance/linear_or_areal_to_areal.hpp

diff --git a/include/boost/geometry/algorithms/detail/distance/linear_or_areal_to_areal.hpp b/include/boost/geometry/algorithms/detail/distance/linear_or_areal_to_areal.hpp
new file mode 100644
index 000000000..bd6bbfa5d
--- /dev/null
+++ b/include/boost/geometry/algorithms/detail/distance/linear_or_areal_to_areal.hpp
@@ -0,0 +1,159 @@
+// Boost.Geometry (aka GGL, Generic Geometry Library)
+
+// Copyright (c) 2014, Oracle and/or its affiliates.
+
+// Contributed and/or modified by Menelaos Karavelas, on behalf of Oracle
+
+// Licensed under the Boost Software License version 1.0.
+// http://www.boost.org/users/license.html
+
+#ifndef BOOST_GEOMETRY_ALGORITHMS_DETAIL_DISTANCE_LINEAR_OR_AREAL_TO_AREAL_HPP
+#define BOOST_GEOMETRY_ALGORITHMS_DETAIL_DISTANCE_LINEAR_OR_AREAL_TO_AREAL_HPP
+
+#include <boost/geometry/core/point_type.hpp>
+
+#include <boost/geometry/strategies/distance.hpp>
+
+#include <boost/geometry/algorithms/intersects.hpp>
+
+#include <boost/geometry/algorithms/detail/distance/linear_to_linear.hpp>
+
+
+namespace boost { namespace geometry
+{
+
+#ifndef DOXYGEN_NO_DETAIL
+namespace detail { namespace distance
+{
+
+
+template
+<
+    typename Linear,
+    typename Areal,
+    typename Strategy,
+    bool UseRTreeOfSegments = true
+>
+struct linear_to_areal
+{
+    typedef typename strategy::distance::services::return_type
+        <
+            Strategy,
+            typename point_type<Linear>::type,
+            typename point_type<Areal>::type
+        >::type return_type;
+
+    static inline return_type apply(Linear const& linear,
+                                    Areal const& areal,
+                                    Strategy const& strategy)
+    {
+        if ( geometry::intersects(linear, areal) )
+        {
+            return 0;
+        }
+
+        return linear_to_linear
+            <
+                Linear, Areal, Strategy, UseRTreeOfSegments
+            >::apply(linear, areal, strategy, false);
+    }
+
+
+    static inline return_type apply(Areal const& areal,
+                                    Linear const& linear,
+                                    Strategy const& strategy)
+    {
+        return apply(linear, areal, strategy);
+    }
+};
+
+
+template
+<
+    typename Areal1,
+    typename Areal2,
+    typename Strategy,
+    bool UseRTreeOfSegments = true
+>
+struct areal_to_areal
+{
+    typedef typename strategy::distance::services::return_type
+        <
+            Strategy,
+            typename point_type<Areal1>::type,
+            typename point_type<Areal2>::type
+        >::type return_type;
+
+    static inline return_type apply(Areal1 const& areal1,
+                                    Areal2 const& areal2,
+                                    Strategy const& strategy)
+    {
+        if ( geometry::intersects(areal1, areal2) )
+        {
+            return 0;
+        }
+
+        return linear_to_linear
+            <
+                Areal1, Areal2, Strategy, UseRTreeOfSegments
+            >::apply(areal1, areal2, strategy, false);
+    }
+};
+
+
+}} // namespace detail::distance
+#endif // DOXYGEN_NO_DETAIL
+
+
+#ifndef DOXYGEN_NO_DISPATCH
+namespace dispatch
+{
+
+template <typename Linear, typename Areal, typename Strategy>
+struct distance
+    <
+        Linear, Areal, Strategy,
+        linear_tag, areal_tag, 
+        strategy_tag_distance_point_segment, false
+    >
+    : detail::distance::linear_to_areal
+        <
+            Linear, Areal, Strategy
+        >
+{};
+
+
+template <typename Areal, typename Linear, typename Strategy>
+struct distance
+    <
+        Areal, Linear, Strategy,
+        areal_tag, linear_tag, 
+        strategy_tag_distance_point_segment, false
+    >
+    : detail::distance::linear_to_areal
+        <
+            Linear, Areal, Strategy
+        >
+{};
+
+
+template <typename Areal1, typename Areal2, typename Strategy>
+struct distance
+    <
+        Areal1, Areal2, Strategy,
+        areal_tag, areal_tag, 
+        strategy_tag_distance_point_segment, false
+    >
+    : detail::distance::areal_to_areal
+        <
+            Areal1, Areal2, Strategy
+        >
+{};
+
+
+} // namespace dispatch
+#endif // DOXYGEN_NO_DISPATCH
+
+}} // namespace boost::geometry
+
+#endif // BOOST_GEOMETRY_ALGORITHMS_DETAIL_DISTANCE_LINEAR_OR_AREAL_TO_AREAL_HPP