From 378e266bc3d484aa653e65cd7a03bd26ddc74181 Mon Sep 17 00:00:00 2001
From: Barend Gehrels <barend@xs4all.nl>
Date: Wed, 27 Apr 2016 14:27:39 +0200
Subject: [PATCH] [cluster] move open_count to cluster_info itself to avoid
 calculating it multiple times. Rename assign_startable... to
 gather_cluster_properties

---
 .../geometry/algorithms/detail/overlay/cluster_info.hpp  | 4 ++++
 .../detail/overlay/enrich_intersection_points.hpp        | 2 +-
 .../algorithms/detail/overlay/handle_colocations.hpp     | 7 +++++--
 .../geometry/algorithms/detail/overlay/traversal.hpp     | 9 ++-------
 4 files changed, 12 insertions(+), 10 deletions(-)

diff --git a/include/boost/geometry/algorithms/detail/overlay/cluster_info.hpp b/include/boost/geometry/algorithms/detail/overlay/cluster_info.hpp
index 4e757e7d1..5b460919f 100644
--- a/include/boost/geometry/algorithms/detail/overlay/cluster_info.hpp
+++ b/include/boost/geometry/algorithms/detail/overlay/cluster_info.hpp
@@ -28,8 +28,12 @@ struct cluster_info
 
     bool switch_source; // For clusters with a touch, conform turn_info uu
 
+    //! Number of open spaces (e.g. 2 for touch)
+    std::size_t open_count;
+
     inline cluster_info()
         : switch_source(false)
+        , open_count(0)
     {}
 };
 
diff --git a/include/boost/geometry/algorithms/detail/overlay/enrich_intersection_points.hpp b/include/boost/geometry/algorithms/detail/overlay/enrich_intersection_points.hpp
index c79c9cf50..021a07e74 100644
--- a/include/boost/geometry/algorithms/detail/overlay/enrich_intersection_points.hpp
+++ b/include/boost/geometry/algorithms/detail/overlay/enrich_intersection_points.hpp
@@ -328,7 +328,7 @@ inline void enrich_intersection_points(Turns& turns,
 
     if (has_colocations)
     {
-        detail::overlay::assign_startable_in_clusters<Reverse1, Reverse2>(
+        detail::overlay::gather_cluster_properties<Reverse1, Reverse2>(
                 clusters, turns, for_operation, geometry1, geometry2);
     }
 
diff --git a/include/boost/geometry/algorithms/detail/overlay/handle_colocations.hpp b/include/boost/geometry/algorithms/detail/overlay/handle_colocations.hpp
index b16260b0b..242f0de00 100644
--- a/include/boost/geometry/algorithms/detail/overlay/handle_colocations.hpp
+++ b/include/boost/geometry/algorithms/detail/overlay/handle_colocations.hpp
@@ -15,6 +15,7 @@
 #include <vector>
 
 #include <boost/range.hpp>
+#include <boost/geometry/algorithms/detail/overlay/cluster_info.hpp>
 #include <boost/geometry/algorithms/detail/overlay/overlay_type.hpp>
 #include <boost/geometry/algorithms/detail/overlay/sort_by_side.hpp>
 #include <boost/geometry/algorithms/detail/overlay/turn_info.hpp>
@@ -498,7 +499,7 @@ template
     typename Geometry1,
     typename Geometry2
 >
-inline void assign_startable_in_clusters(Clusters& clusters, Turns& turns,
+inline void gather_cluster_properties(Clusters& clusters, Turns& turns,
         operation_type for_operation,
         Geometry1 const& geometry1, Geometry2 const& geometry2)
 {
@@ -516,7 +517,8 @@ inline void assign_startable_in_clusters(Clusters& clusters, Turns& turns,
     for (typename Clusters::iterator mit = clusters.begin();
          mit != clusters.end(); ++mit)
     {
-        std::set<signed_size_type> const& ids = mit->second.turn_indices;
+        cluster_info& cinfo = mit->second;
+        std::set<signed_size_type> const& ids = cinfo.turn_indices;
         if (ids.empty())
         {
             continue;
@@ -570,6 +572,7 @@ inline void assign_startable_in_clusters(Clusters& clusters, Turns& turns,
             }
         }
 
+        cinfo.open_count = sbs.open_count(turns);
     }
 }
 
diff --git a/include/boost/geometry/algorithms/detail/overlay/traversal.hpp b/include/boost/geometry/algorithms/detail/overlay/traversal.hpp
index 51f014cd9..00d31c370 100644
--- a/include/boost/geometry/algorithms/detail/overlay/traversal.hpp
+++ b/include/boost/geometry/algorithms/detail/overlay/traversal.hpp
@@ -493,13 +493,8 @@ struct traversal
 
         sbs.apply(turn.point);
 
-        std::size_t open_count = 0;
-        if (is_union) //  && ! cinfo.switch_source)
-        {
-            open_count = sbs.open_count(m_turns);
-        }
-
-        is_touching = open_count > 1;
+        // TODO: use also cinfo.switch_source
+        is_touching = is_union && cinfo.open_count > 1;
         if (is_touching)
         {
             sbs.reverse();