From 15c674d5c91a985f3bb1cbf970f590ca113ccae0 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Mael=20Rouxel-Labb=C3=A9?=
 <mael.rouxel.labbe@geometryfactory.com>
Date: Tue, 14 Feb 2023 14:59:10 +0100
Subject: [PATCH] Move helper classes to SLS_aux.h

---
 .../Straight_skeleton_2/Polygon_iterators.h   |  6 +-
 .../Straight_skeleton_aux.h                   | 65 +++++++++++++++++++
 .../include/CGAL/create_offset_polygons_2.h   | 61 +----------------
 .../CGAL/create_weighted_offset_polygons_2.h  |  4 +-
 4 files changed, 70 insertions(+), 66 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 09b8caec5bc..01328936363 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
@@ -13,7 +13,8 @@
 
 #include <CGAL/license/Straight_skeleton_2.h>
 
-#include <boost/mpl/has_xxx.hpp>
+#include <CGAL/Straight_skeleton_2/Straight_skeleton_aux.h>
+
 #include <boost/shared_ptr.hpp>
 
 #include <type_traits>
@@ -21,9 +22,6 @@
 namespace CGAL {
 namespace CGAL_SS_i {
 
-// to distinguish between SequenceContainers of points, and GeneralPolygonWithHoles_2
-BOOST_MPL_HAS_XXX_TRAIT_DEF(Hole_const_iterator)
-
 // Polygon_2-type container
 template <typename Poly>
 inline typename Poly::const_iterator
diff --git a/Straight_skeleton_2/include/CGAL/Straight_skeleton_2/Straight_skeleton_aux.h b/Straight_skeleton_2/include/CGAL/Straight_skeleton_2/Straight_skeleton_aux.h
index 8a2ad91ab86..05e220c3968 100644
--- a/Straight_skeleton_2/include/CGAL/Straight_skeleton_2/Straight_skeleton_aux.h
+++ b/Straight_skeleton_2/include/CGAL/Straight_skeleton_2/Straight_skeleton_aux.h
@@ -17,6 +17,9 @@
 #include <CGAL/Straight_skeleton_2/debug.h>
 #include <CGAL/Straight_skeleton_2/test.h>
 
+#include <CGAL/Polygon_with_holes_2.h>
+
+#include <boost/mpl/has_xxx.hpp>
 #include <boost/mpl/if.hpp>
 #include <boost/mpl/or.hpp>
 #include <boost/none.hpp>
@@ -171,6 +174,68 @@ private:
   Handle mE[3];
 } ;
 
+template<class U, class V>
+struct Is_same_type { typedef Tag_false type ; } ;
+
+template<class U>
+struct Is_same_type<U,U> { typedef Tag_true type ; } ;
+
+// to distinguish between SequenceContainers of points, and GeneralPolygonWithHoles_2
+BOOST_MPL_HAS_XXX_TRAIT_DEF(Hole_const_iterator)
+
+// The return type of create_(weighted)_interior/exterior_skeleton_and_offset_polygons_2:
+// - if polygon input is a model of 'GeneralPolygonWithHoles_2', the return type
+//   should be the internal (hole-less) polygon type GeneralPolygonWithHoles_2::Polygon_2
+// - if polygon input is just a sequence container of points (e.g. Polygon_2), then the same type
+//   is expected in output
+template <typename Polygon, typename OfK,
+          bool has_holes = CGAL_SS_i::has_Hole_const_iterator<Polygon>::value>
+struct Default_return_polygon_type // Polygon type supports holes
+{
+  typedef typename std::conditional<std::is_same<
+                                      typename Kernel_traits<typename boost::range_value<
+                                        typename Polygon::Polygon_2>::type>::Kernel,
+                                      OfK>::value,
+                                    typename Polygon::Polygon_2, // correct kernel
+                                    CGAL::Polygon_2<OfK> /*incorrect kernel*/ >::type type;
+};
+
+template <typename Polygon, typename OfK>
+struct Default_return_polygon_type<Polygon, OfK, false> // Polygon type does NOT support holes
+{
+  typedef typename std::conditional<std::is_same<
+                                      typename Kernel_traits<typename boost::range_value<Polygon>::type>::Kernel,
+                                      OfK>::value,
+                                    Polygon, // correct kernel
+                                    CGAL::Polygon_2<OfK> /*incorrect kernel*/ >::type type;
+};
+
+// The return type of create_interior/exterior_skeleton_and_offset_polygons_with_holes_2:
+// - if polygon input is a model of 'GeneralPolygonWithHoles_2', the return type should be the same
+// - if polygon input is just a sequence container of points (e.g. Polygon_2), then use
+//   General_polygon_with_holes_2<Polygon>
+template <typename Polygon, typename OfK,
+          bool has_holes = CGAL_SS_i::has_Hole_const_iterator<Polygon>::value>
+struct Default_return_polygon_with_holes_type // Polygon type supports holes
+{
+  typedef typename std::conditional<std::is_same<
+                                      typename Kernel_traits<typename boost::range_value<
+                                        typename Polygon::Polygon_2>::type>::Kernel,
+                                      OfK>::value,
+                                    Polygon, // correct kernel
+                                    CGAL::Polygon_with_holes_2<OfK> /*incorrect kernel*/ >::type type;
+};
+
+template <typename Polygon, typename OfK>
+struct Default_return_polygon_with_holes_type<Polygon, OfK, false> // Polygon type does NOT support holes
+{
+  // Maybe on paper the `conditional<true>` should be `General_polygon_with_holes_2<Polygon>`...
+  typedef typename std::conditional<std::is_same<
+                                      typename Kernel_traits<typename boost::range_value<Polygon>::type>::Kernel,
+                                      OfK>::value,
+                                    CGAL::Polygon_with_holes_2<OfK>, // correct kernel but no holes
+                                    CGAL::Polygon_with_holes_2<OfK> /*incorrect kernel*/ >::type type;
+};
 
 } // namespace CGAL_SS_i
 
diff --git a/Straight_skeleton_2/include/CGAL/create_offset_polygons_2.h b/Straight_skeleton_2/include/CGAL/create_offset_polygons_2.h
index 20c5c85ab42..3903767cf07 100644
--- a/Straight_skeleton_2/include/CGAL/create_offset_polygons_2.h
+++ b/Straight_skeleton_2/include/CGAL/create_offset_polygons_2.h
@@ -14,6 +14,7 @@
 
 #include <CGAL/license/Straight_skeleton_2.h>
 
+#include <CGAL/Straight_skeleton_2/Straight_skeleton_aux.h>
 #include <CGAL/create_straight_skeleton_2.h>
 #include <CGAL/compute_outer_frame_margin.h>
 #include <CGAL/Polygon_offset_builder_2.h>
@@ -42,66 +43,6 @@ namespace CGAL {
 
 namespace CGAL_SS_i {
 
-template<class U, class V>
-struct Is_same_type { typedef Tag_false type ; } ;
-
-template<class U>
-struct Is_same_type<U,U> { typedef Tag_true type ; } ;
-
-// The return type of create_interior/exterior_skeleton_and_offset_polygons_2:
-// - if polygon input is a model of 'GeneralPolygonWithHoles_2', the return type
-//   should be the internal (hole-less) polygon type GeneralPolygonWithHoles_2::Polygon_2
-// - if polygon input is just a sequence container of points (e.g. Polygon_2), then the same type
-//   is expected in output
-template <typename Polygon, typename OfK,
-          bool has_holes = CGAL_SS_i::has_Hole_const_iterator<Polygon>::value>
-struct Default_return_polygon_type // Polygon type supports holes
-{
-  typedef typename std::conditional<std::is_same<
-                                      typename Kernel_traits<typename boost::range_value<
-                                        typename Polygon::Polygon_2>::type>::Kernel,
-                                      OfK>::value,
-                                    typename Polygon::Polygon_2, // correct kernel
-                                    CGAL::Polygon_2<OfK> /*incorrect kernel*/ >::type type;
-};
-
-template <typename Polygon, typename OfK>
-struct Default_return_polygon_type<Polygon, OfK, false> // Polygon type does NOT support holes
-{
-  typedef typename std::conditional<std::is_same<
-                                      typename Kernel_traits<typename boost::range_value<Polygon>::type>::Kernel,
-                                      OfK>::value,
-                                    Polygon, // correct kernel
-                                    CGAL::Polygon_2<OfK> /*incorrect kernel*/ >::type type;
-};
-
-// The return type of create_interior/exterior_skeleton_and_offset_polygons_with_holes_2:
-// - if polygon input is a model of 'GeneralPolygonWithHoles_2', the return type should be the same
-// - if polygon input is just a sequence container of points (e.g. Polygon_2), then use
-//   General_polygon_with_holes_2<Polygon>
-template <typename Polygon, typename OfK,
-          bool has_holes = CGAL_SS_i::has_Hole_const_iterator<Polygon>::value>
-struct Default_return_polygon_with_holes_type // Polygon type supports holes
-{
-  typedef typename std::conditional<std::is_same<
-                                      typename Kernel_traits<typename boost::range_value<
-                                        typename Polygon::Polygon_2>::type>::Kernel,
-                                      OfK>::value,
-                                    Polygon, // correct kernel
-                                    CGAL::Polygon_with_holes_2<OfK> /*incorrect kernel*/ >::type type;
-};
-
-template <typename Polygon, typename OfK>
-struct Default_return_polygon_with_holes_type<Polygon, OfK, false> // Polygon type does NOT support holes
-{
-  // Maybe on paper the `conditional<true>` should be `General_polygon_with_holes_2<Polygon>`...
-  typedef typename std::conditional<std::is_same<
-                                      typename Kernel_traits<typename boost::range_value<Polygon>::type>::Kernel,
-                                      OfK>::value,
-                                    CGAL::Polygon_with_holes_2<OfK>, // correct kernel but no holes
-                                    CGAL::Polygon_with_holes_2<OfK> /*incorrect kernel*/ >::type type;
-};
-
 template<class FT, class PointIterator, class HoleIterator, class K>
 boost::shared_ptr< Straight_skeleton_2<K> >
 create_partial_interior_straight_skeleton_2 ( FT const&     aMaxTime
diff --git a/Straight_skeleton_2/include/CGAL/create_weighted_offset_polygons_2.h b/Straight_skeleton_2/include/CGAL/create_weighted_offset_polygons_2.h
index 007766940d9..fe5d369186e 100644
--- a/Straight_skeleton_2/include/CGAL/create_weighted_offset_polygons_2.h
+++ b/Straight_skeleton_2/include/CGAL/create_weighted_offset_polygons_2.h
@@ -14,8 +14,8 @@
 
 #include <CGAL/license/Straight_skeleton_2.h>
 
-#include <CGAL/create_straight_skeleton_2.h>
-#include <CGAL/create_weighted_offset_polygons_2.h>
+#include <CGAL/Straight_skeleton_2/Straight_skeleton_aux.h>
+#include <CGAL/create_offset_polygons_2.h>
 #include <CGAL/compute_outer_frame_margin.h>
 #include <CGAL/Polygon_offset_builder_2.h>
 #include <CGAL/Straight_skeleton_converter_2.h>