From b51b4d87130682ea726cda7641b33fe150f0906e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Mael=20Rouxel-Labb=C3=A9?=
 <mael.rouxel.labbe@geometryfactory.com>
Date: Mon, 13 Feb 2023 16:04:33 +0100
Subject: [PATCH] Fix SLS iterators to actually handle all possible models

---
 .../Straight_skeleton_2/Polygon_iterators.h   | 95 +++++++++----------
 1 file changed, 44 insertions(+), 51 deletions(-)

diff --git a/Straight_skeleton_2/include/CGAL/Straight_skeleton_2/Polygon_iterators.h b/Straight_skeleton_2/include/CGAL/Straight_skeleton_2/Polygon_iterators.h
index 4740194987b..8e63332b913 100644
--- a/Straight_skeleton_2/include/CGAL/Straight_skeleton_2/Polygon_iterators.h
+++ b/Straight_skeleton_2/include/CGAL/Straight_skeleton_2/Polygon_iterators.h
@@ -13,72 +13,65 @@
 
 #include <CGAL/license/Straight_skeleton_2.h>
 
-#include <CGAL/Polygon_with_holes_2.h>
-
 #include <boost/shared_ptr.hpp>
 
+#include <type_traits>
+
 namespace CGAL {
 namespace CGAL_SS_i {
 
 // to distinguish between SequenceContainers of points, and GeneralPolygonWithHoles_2
 BOOST_MPL_HAS_XXX_TRAIT_DEF(Hole_const_iterator)
 
-// Generic container
-template<class Poly>
-inline typename Poly::const_iterator vertices_begin ( Poly const& aPoly )
-{ return aPoly.begin() ; }
+// Polygon_2-type container
+template <typename Poly>
+inline typename Poly::const_iterator
+vertices_begin(const Poly& aPoly,
+               std::enable_if_t<!has_Hole_const_iterator<Poly>::value>* = nullptr)
+{ return aPoly.begin(); }
 
-template<class Poly>
-inline typename Poly::const_iterator vertices_end ( Poly const& aPoly )
-{ return aPoly.end() ; }
+template <typename Poly>
+inline typename Poly::const_iterator
+vertices_end(const Poly& aPoly,
+             std::enable_if_t<!has_Hole_const_iterator<Poly>::value>* = nullptr)
+{ return aPoly.end(); }
 
-template<class Poly>
-inline typename Poly::const_iterator vertices_begin ( boost::shared_ptr<Poly> const& aPoly )
-{ return aPoly->begin() ; }
+template <typename Poly>
+inline typename Poly::const_iterator
+vertices_begin(const boost::shared_ptr<Poly>& aPoly,
+               std::enable_if_t<!has_Hole_const_iterator<Poly>::value>* = nullptr)
+{ return aPoly->begin(); }
 
-template<class Poly>
-inline typename Poly::const_iterator vertices_end ( boost::shared_ptr<Poly> const& aPoly )
-{ return aPoly->end() ; }
+template <typename Poly>
+inline typename Poly::const_iterator
+vertices_end(const boost::shared_ptr<Poly> & aPoly,
+             std::enable_if_t<!has_Hole_const_iterator<Poly>::value>* = nullptr)
+{ return aPoly->end(); }
 
-// Polygon_2
-template<class K, class C>
-inline typename Polygon_2<K,C>::Vertex_const_iterator
-vertices_begin ( Polygon_2<K,C> const& aPoly )
-{ return aPoly.vertices_begin() ; }
+// Polygon_with_holes_2-type container
+template <typename PolyWithHoles>
+inline typename PolyWithHoles::Polygon_2::const_iterator
+vertices_begin(const PolyWithHoles& aPoly,
+               std::enable_if_t<has_Hole_const_iterator<PolyWithHoles>::value>* = nullptr)
+{ return aPoly.outer_boundary().begin(); }
 
-template<class K, class C>
-inline typename Polygon_2<K,C>::Vertex_const_iterator
-vertices_end( Polygon_2<K,C> const& aPoly )
-{ return aPoly.vertices_end() ; }
+template <typename PolyWithHoles>
+inline typename PolyWithHoles::Polygon_2::const_iterator
+vertices_end(const PolyWithHoles& aPoly,
+             std::enable_if_t<has_Hole_const_iterator<PolyWithHoles>::value>* = nullptr)
+{ return aPoly.outer_boundary().end(); }
 
-template<class K, class C>
-inline typename Polygon_2<K,C>::Vertex_const_iterator vertices_begin ( boost::shared_ptr<Polygon_2<K,C> > const& aPoly )
-{ return aPoly->vertices_begin() ; }
+template <typename PolyWithHoles>
+inline typename PolyWithHoles::Polygon_2::const_iterator
+vertices_begin(const boost::shared_ptr<PolyWithHoles>& aPoly,
+               std::enable_if_t<has_Hole_const_iterator<PolyWithHoles>::value>* = nullptr)
+{ return aPoly->outer_boundary().begin(); }
 
-template<class K, class C>
-inline typename Polygon_2<K,C>::Vertex_const_iterator vertices_end( boost::shared_ptr<Polygon_2<K,C> > const& aPoly )
-{ return aPoly->vertices_end() ; }
-
-// Polygon_with_holes_2
-template<class K, class C>
-inline typename Polygon_with_holes_2<K,C>::Polygon_2::Vertex_const_iterator
-vertices_begin ( Polygon_with_holes_2<K,C> const& aPoly )
-{ return aPoly.outer_boundary().vertices_begin() ; }
-
-template<class K, class C>
-inline typename Polygon_with_holes_2<K,C>::Polygon_2::Vertex_const_iterator
-vertices_end( Polygon_with_holes_2<K,C> const& aPoly )
-{ return aPoly.outer_boundary().vertices_end() ; }
-
-template<class K, class C>
-inline typename Polygon_with_holes_2<K,C>::Polygon_2::Vertex_const_iterator
-vertices_begin ( boost::shared_ptr<Polygon_with_holes_2<K,C> > const& aPoly )
-{ return aPoly->outer_boundary().vertices_begin() ; }
-
-template<class K, class C>
-inline typename Polygon_with_holes_2<K,C>::Polygon_2::Vertex_const_iterator
-vertices_end( boost::shared_ptr<Polygon_with_holes_2<K,C> > const& aPoly )
-{ return aPoly->outer_boundary().vertices_end() ; }
+template <typename PolyWithHoles>
+inline typename PolyWithHoles::Polygon_2::const_iterator
+vertices_end(const boost::shared_ptr<PolyWithHoles>& aPoly,
+             std::enable_if_t<has_Hole_const_iterator<PolyWithHoles>::value>* = nullptr)
+{ return aPoly->outer_boundary().end(); }
 
 } // namespace CGAL_SS_i
 } // namespace CGAL