Unique_hash_map can not be specialized by Face_handle?

[xuanjueheshang]

I got a problem.

I made a voronoi diagram with the voronoi library. Then I wanted to bind some data to "some special faces". A Face_handle can be created for me when I use the "locate" methed, Then, what should i do to bind data to it? Or is there a method to convert Face_handle to Face_iterator?

Unique_hash_map can not be specialized by Face_handle. Face_iterator works well. ==! Or there is a special skill?

Sorry for my poor English.

Environment

• Operating system (Windows/Mac/Linux, 32/64 bits): Win 10
• Compiler: MSVC
• Release or debug mode: Release/Debug
• CGAL version:5.3
• Boost version:1.76

[lrineau]

1. You can modify the "face" type of the diagram to add new data members to it.
2. I am surprised by your statement "Unique_hash_map can not be specialized by Face_handle". You can please share you code and show us what does not work at you wish?

[xuanjueheshang]

thanks.
here is the code.
main.zip

[lrineau]

I get it.

The compilation error is:

.../Hash_map/include/CGAL/Handle_hash_function.h:37:11: error: no type named ‘value_type’ in ‘struct std::iterator_traits<CGAL::VoronoiDiagram_2::Internal::Handle_adaptor<CGAL::VoronoiDiagram_2::Internal::Face<CGAL::Voronoi_diagram_2<CGAL::Delaunay_triangulation_2<CGAL::Epick>, CGAL::Delaunay_triangulation_adaptation_traits_2<CGAL::Delaunay_triangulation_2<CGAL::Epick> >, CGAL::Delaunay_triangulation_caching_degeneracy_removal_policy_2<CGAL::Delaunay_triangulation_2<CGAL::Epick> > > > > >’
   37 |           sizeof( typename std::iterator_traits<H>::value_type);
      |           ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

The issue is that CGAL::VoronoiDiagram_2::Internal::Handle_adaptor<T> is not a correct model of our Handle concept. Here is a patch to fix that:

diff --git a/Voronoi_diagram_2/include/CGAL/Voronoi_diagram_2/Handle_adaptor.h b/Voronoi_diagram_2/include/CGAL/Voronoi_diagram_2/Handle_adaptor.h
index 91b5be76f09..8ed30759595 100644
--- a/Voronoi_diagram_2/include/CGAL/Voronoi_diagram_2/Handle_adaptor.h
+++ b/Voronoi_diagram_2/include/CGAL/Voronoi_diagram_2/Handle_adaptor.h
@@ -33,6 +33,8 @@ class Handle_adaptor
   typedef T&     reference;
   typedef const T*  const_pointer;
   typedef const T&  const_reference;
+  typedef void iterator_category;
+  typedef std::ptrdiff_t difference_type;
 
  public:
   Handle_adaptor() : t() {}

Submitted as pull-request #5981.

[xuanjueheshang]

Thanks