From e294cd8fe9542944dd6113fb2211fd5ecf4779cf Mon Sep 17 00:00:00 2001
From: Laurent Rineau <laurent.rineau@cgal.org>
Date: Tue, 9 May 2017 17:47:18 +0200
Subject: [PATCH] Fix new (recycled) time stamps when a TDS is copied

---
 Mesh_3/test/Mesh_3/test_meshing_utilities.h   | 29 +++++++++++++++++++
 STL_Extension/include/CGAL/Time_stamper.h     |  8 ++++-
 .../STL_Extension/test_Compact_container.cpp  | 19 ++++++++++++
 3 files changed, 55 insertions(+), 1 deletion(-)

diff --git a/Mesh_3/test/Mesh_3/test_meshing_utilities.h b/Mesh_3/test/Mesh_3/test_meshing_utilities.h
index ca657b17288..580cc66b454 100644
--- a/Mesh_3/test/Mesh_3/test_meshing_utilities.h
+++ b/Mesh_3/test/Mesh_3/test_meshing_utilities.h
@@ -54,6 +54,34 @@
 struct Bissection_tag {};
 struct Polyhedral_tag {};
 
+// Verify that the time stamps of vertices and cells are strictly
+// increasing
+template <typename C3t3>
+void verify_time_stamps(const C3t3& c3t3, CGAL::Sequential_tag) {
+  typedef typename C3t3::Triangulation::Triangulation_data_structure TDS;
+  const TDS& tds = c3t3.triangulation().tds();
+  {
+    typename TDS::Vertex_iterator prev = tds.vertices_begin();
+    assert(0 == prev->time_stamp());
+    typename TDS::Vertex_iterator vit = prev;
+    ++vit;
+    for(; vit != tds.vertices_end(); ++vit, ++prev) {
+      assert(prev->time_stamp() < vit->time_stamp());
+    }
+  }
+  {
+    typename TDS::Cell_iterator prev = tds.cells_begin();
+    typename TDS::Cell_iterator cit = prev;
+    ++cit;
+    for(; cit != tds.cells_end(); ++cit, ++prev) {
+      assert(prev->time_stamp() < cit->time_stamp());
+    }
+  }
+}
+
+// Do not verify time stamps in parallel mode
+template <typename C3t3>
+void verify_time_stamps(const C3t3&, CGAL::Parallel_tag) {}
 
 template <typename K>
 struct Tester
@@ -180,6 +208,7 @@ struct Tester
                    const std::size_t min_cells_expected = 0,
                    const std::size_t max_cells_expected = STD_SIZE_T_MAX ) const
   {
+    verify_time_stamps(c3t3, typename C3t3::Concurrency_tag());
     //-------------------------------------------------------
     // Verifications
     //-------------------------------------------------------
diff --git a/STL_Extension/include/CGAL/Time_stamper.h b/STL_Extension/include/CGAL/Time_stamper.h
index 57c58f5ce58..a35f29a2e30 100644
--- a/STL_Extension/include/CGAL/Time_stamper.h
+++ b/STL_Extension/include/CGAL/Time_stamper.h
@@ -39,7 +39,13 @@ struct Time_stamper
   void set_time_stamp(T* pt) {
     if(pt->time_stamp() == std::size_t(-1))
       pt->set_time_stamp(time_stamp_++);
-    // else: the time stamp is re-used
+    else {
+      // else: the time stamp is re-used
+
+      // Enforces that the time stamp is greater than the current value.
+      // That is used when a TDS_3 is copied.
+      time_stamp_ = (std::max)(time_stamp_, pt->time_stamp() + 1);
+    }
   }
 
 
diff --git a/STL_Extension/test/STL_Extension/test_Compact_container.cpp b/STL_Extension/test/STL_Extension/test_Compact_container.cpp
index 567e78c872f..19d40d71549 100644
--- a/STL_Extension/test/STL_Extension/test_Compact_container.cpp
+++ b/STL_Extension/test/STL_Extension/test_Compact_container.cpp
@@ -19,6 +19,7 @@ template <typename Has_timestamp_ = CGAL::Tag_true>
 struct Node_1
 : public CGAL::Compact_container_base
 {
+  Node_1() {} // // it is important `time_stamp_` is not initialized
   bool operator==(const Node_1 &) const { return true; }
   bool operator!=(const Node_1 &) const { return false; }
   bool operator< (const Node_1 &) const { return false; }
@@ -273,6 +274,22 @@ void test_index(const Cont &C)
   }
 }
 
+template < class Cont >
+void test_time_stamps() {
+  Cont c1;
+  for (std::size_t i = 0 ; i < 10 ; ++i)
+    c1.emplace();
+  typename Cont::iterator it = c1.begin();
+  for (std::size_t i = 0 ; i < 10 ; ++i) {
+    assert(i == it++->time_stamp());
+  }
+  Cont c2(c1);
+  it = c2.begin();
+  for (std::size_t i = 0 ; i < 10 ; ++i) {
+    assert(i == it++->time_stamp());
+  }
+}
+
 struct Incomplete_struct;
 
 int main()
@@ -298,6 +315,8 @@ int main()
   C3 c3;  test(c3);
   C4 c4;  test(c4);
 
+  test_time_stamps<C4>();
+
   // Check the time stamper policies
   if(! boost::is_base_of<CGAL::Time_stamper<T1>,
      C1::Time_stamper_impl>::value)