From b35e34238a20a953120d2db884096b133ebae4cb Mon Sep 17 00:00:00 2001
From: Simon Giraudot <simon.giraudot@geometryfactory.com>
Date: Tue, 15 Sep 2015 17:20:25 +0200
Subject: [PATCH] Bugfix: if 2 input points are equal, avoid infinite loop and
 terminate non-empty cluster

---
 .../CGAL/hierarchy_simplify_point_set.h       | 37 ++++++++++---------
 .../hierarchy_simplification_test.cpp         | 20 ++++++----
 2 files changed, 31 insertions(+), 26 deletions(-)

diff --git a/Point_set_processing_3/include/CGAL/hierarchy_simplify_point_set.h b/Point_set_processing_3/include/CGAL/hierarchy_simplify_point_set.h
index 3388b7c202f..ac6976aae45 100644
--- a/Point_set_processing_3/include/CGAL/hierarchy_simplify_point_set.h
+++ b/Point_set_processing_3/include/CGAL/hierarchy_simplify_point_set.h
@@ -251,25 +251,26 @@ namespace CGAL {
 		++ current_cluster_size;
 	      }
 
-	    // If one of the clusters is empty, only keep the non-empty one
+	    // If one of the clusters is empty, stop to avoid infinite
+	    // loop and keep the non-empty one
 	    if (current_cluster->first.empty () || negative_side->first.empty ())
 	      {
-		cluster_iterator empty, nonempty;
-		if (current_cluster->first.empty ())
-		  {
-		    empty = current_cluster;
-		    nonempty = negative_side;
-		  }
-		else
-		  {
-		    empty = negative_side;
-		    nonempty = current_cluster;
-		  }
+		cluster_iterator nonempty = (current_cluster->first.empty ()
+					     ? negative_side : current_cluster);
 
-		nonempty->second = internal::hsps_centroid (nonempty->first.begin (), nonempty->first.end (),
-							   point_pmap, Kernel());
-
-		clusters_stack.erase (empty);
+		// Compute the centroid
+		nonempty->second = internal::hsps_centroid (nonempty->first.begin (),
+							    nonempty->first.end (),
+							    point_pmap, Kernel());
+		
+		internal::hsc_terminate_cluster (nonempty->first,
+						 points_to_keep,
+						 points_to_remove,
+						 point_pmap,
+						 nonempty->second,
+						 Kernel ());
+		clusters_stack.pop_front ();
+		clusters_stack.pop_front ();
 	      }
 	    else
 	      {
@@ -278,8 +279,8 @@ namespace CGAL {
 		
 		// Compute the first centroid
 		current_cluster->second = internal::hsps_centroid (current_cluster->first.begin (),
-								  current_cluster->first.end (),
-								  point_pmap, Kernel());
+								   current_cluster->first.end (),
+								   point_pmap, Kernel());
 
 		// The second centroid can be computed with the first and
 		// the old ones :
diff --git a/Point_set_processing_3/test/Point_set_processing_3/hierarchy_simplification_test.cpp b/Point_set_processing_3/test/Point_set_processing_3/hierarchy_simplification_test.cpp
index c996924fb3f..65cc416e5d9 100644
--- a/Point_set_processing_3/test/Point_set_processing_3/hierarchy_simplification_test.cpp
+++ b/Point_set_processing_3/test/Point_set_processing_3/hierarchy_simplification_test.cpp
@@ -16,10 +16,14 @@ typedef Kernel::Point_3 Point;
 typedef Kernel::FT FT;
 
 void test (std::vector<Point>& input,
-	   int result1 = 1, int result2 = 1, int result3 = 1, int result4 = 1)
+	   int result0 = 1, int result1 = 1, int result2 = 1, int result3 = 1, int result4 = 1)
 {
   typename std::vector<Point>::iterator it = 
-    CGAL::hierarchy_simplify_point_set (input.begin (), input.end ());
+    CGAL::hierarchy_simplify_point_set (input.begin (), input.end (), 1);
+  if (result0 > 0 && std::distance (input.begin (), it) != (result0))
+    exit (EXIT_FAILURE);
+
+  it = CGAL::hierarchy_simplify_point_set (input.begin (), input.end ());
   if (result1 > 0 && std::distance (input.begin (), it) != (result1))
     exit (EXIT_FAILURE);
 
@@ -61,25 +65,25 @@ int main(void)
   // Test 2 points
   input.push_back (Point (0., 0., 0.));
   input.push_back (Point (1., 0., 0.));
-  test (input);
+  test (input, 2);
 
   // Test line
   for (std::size_t i = 0; i < 1000; ++ i)
     input.push_back (Point (0., 0., i));
-  test (input, 128, 16, 1, 1);
+  test (input, input.size (), 128, 16, 1, 1);
   
   // Test plane
   for (std::size_t i = 0; i < 128; ++ i)
     for (std::size_t j = 0; j < 128; ++ j)
       input.push_back (Point (0., j, i));
-  test (input, 2048, 256, 32, 1);
+  test (input, input.size (), 2048, 256, 32, 1);
   
   // Test random
   for (std::size_t i = 0; i < 10000; ++ i)
     input.push_back (Point (rand() / (FT)RAND_MAX,
-			    rand() / (FT)RAND_MAX,
-			    rand() / (FT)RAND_MAX));
-  test (input, -1, -1, -1, -1);
+  			    rand() / (FT)RAND_MAX,
+  			    rand() / (FT)RAND_MAX));
+  test (input, input.size (), -1, -1, -1, -1);
   
   return EXIT_SUCCESS;
 }