From e431c4e481e11fb4b933010d759f7d4373c8f220 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?S=C3=A9bastien=20Loriot?= <sebastien.loriot@cgal.org>
Date: Tue, 14 Feb 2023 14:16:22 +0100
Subject: [PATCH 1/2] early exit if the mesh is empty

---
 .../include/CGAL/Polygon_mesh_processing/orientation.h       | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/orientation.h b/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/orientation.h
index f5b5f9392a75..01e5cdd5268a 100644
--- a/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/orientation.h
+++ b/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/orientation.h
@@ -1364,6 +1364,9 @@ void orient_to_bound_a_volume(TriangleMesh& tm,
   typedef typename GetGeomTraits<TriangleMesh, NamedParameters>::type              GT;
   typedef typename GetInitializedFaceIndexMap<TriangleMesh, NamedParameters>::type FaceIndexMap;
 
+  std::size_t nbf = num_faces(tm);
+  if (nbf == 0) return;
+
   CGAL_precondition(is_closed(tm));
   CGAL_precondition(is_triangle_mesh(tm));
 
@@ -1377,7 +1380,7 @@ void orient_to_bound_a_volume(TriangleMesh& tm,
   GT gt = choose_parameter<GT>(get_parameter(np, internal_np::geom_traits));
   FaceIndexMap fid_map = CGAL::get_initialized_face_index_map(tm, np);
 
-  std::vector<std::size_t> face_cc(num_faces(tm), std::size_t(-1));
+  std::vector<std::size_t> face_cc(nbf, std::size_t(-1));
   std::vector<std::size_t> nesting_levels;
   std::vector<bool> is_cc_outward_oriented;
   Constant_property_map<face_descriptor, std::size_t> vidmap(0); // dummy map not used

From 0c37af1be9b2fce2c1f4fa09d86565b7068b288b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?S=C3=A9bastien=20Loriot?= <sebastien.loriot@cgal.org>
Date: Thu, 16 Feb 2023 14:36:58 +0100
Subject: [PATCH 2/2] num_faces is not tight

---
 .../include/CGAL/Polygon_mesh_processing/orientation.h       | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/orientation.h b/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/orientation.h
index 01e5cdd5268a..b54f44995696 100644
--- a/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/orientation.h
+++ b/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/orientation.h
@@ -1364,8 +1364,7 @@ void orient_to_bound_a_volume(TriangleMesh& tm,
   typedef typename GetGeomTraits<TriangleMesh, NamedParameters>::type              GT;
   typedef typename GetInitializedFaceIndexMap<TriangleMesh, NamedParameters>::type FaceIndexMap;
 
-  std::size_t nbf = num_faces(tm);
-  if (nbf == 0) return;
+  if (is_empty(tm)) return;
 
   CGAL_precondition(is_closed(tm));
   CGAL_precondition(is_triangle_mesh(tm));
@@ -1380,7 +1379,7 @@ void orient_to_bound_a_volume(TriangleMesh& tm,
   GT gt = choose_parameter<GT>(get_parameter(np, internal_np::geom_traits));
   FaceIndexMap fid_map = CGAL::get_initialized_face_index_map(tm, np);
 
-  std::vector<std::size_t> face_cc(nbf, std::size_t(-1));
+  std::vector<std::size_t> face_cc(num_faces(tm), std::size_t(-1));
   std::vector<std::size_t> nesting_levels;
   std::vector<bool> is_cc_outward_oriented;
   Constant_property_map<face_descriptor, std::size_t> vidmap(0); // dummy map not used