From e2d11a0fc5b384fd65bdaec27b4ed9d5c0212a59 Mon Sep 17 00:00:00 2001
From: Laurent Rineau <laurent.rineau@cgal.org>
Date: Wed, 18 Dec 2024 13:44:54 +0100
Subject: [PATCH] allow a range as parameter

The preview implementation enforced the use of a full container.
---
 Mesh_3/include/CGAL/make_mesh_3.h                |  6 +++---
 .../Mesh_3/test_meshing_unit_tetrahedron.cpp     | 12 ++++++++++++
 .../STL_Extension/internal/mesh_option_classes.h | 16 ++++++++++++----
 3 files changed, 27 insertions(+), 7 deletions(-)

diff --git a/Mesh_3/include/CGAL/make_mesh_3.h b/Mesh_3/include/CGAL/make_mesh_3.h
index 04de44c7d73..8563c016e41 100644
--- a/Mesh_3/include/CGAL/make_mesh_3.h
+++ b/Mesh_3/include/CGAL/make_mesh_3.h
@@ -88,11 +88,11 @@ add_points_from_generator(C3T3& c3t3,
       }
     };
 
+  auto output_it = boost::make_function_output_iterator(push_initial_point);
   if (nb_initial_points > 0)
-    generator(boost::make_function_output_iterator(push_initial_point), nb_initial_points);
+    generator(output_it, nb_initial_points);
   else
-    generator(boost::make_function_output_iterator(push_initial_point));
-
+    generator(output_it);
 
   // Insert points and set their index and dimension
   for (const auto& [wpoint, dimension, index] : initial_points)
diff --git a/Mesh_3/test/Mesh_3/test_meshing_unit_tetrahedron.cpp b/Mesh_3/test/Mesh_3/test_meshing_unit_tetrahedron.cpp
index e8e9268e323..6276758bfcc 100644
--- a/Mesh_3/test/Mesh_3/test_meshing_unit_tetrahedron.cpp
+++ b/Mesh_3/test/Mesh_3/test_meshing_unit_tetrahedron.cpp
@@ -10,6 +10,14 @@
 
 #include <sstream>
 
+template <typename Range> class Non_copyable_range_view {
+  Range& r;
+public:
+  Non_copyable_range_view(Range& r) : r(r) {}
+  auto begin() const { return r.begin(); }
+  auto end() const { return r.end(); }
+};
+
 template <typename K, typename Concurrency_tag = CGAL::Sequential_tag>
 struct Polyhedron_tester : public Tester<K>
 {
@@ -78,6 +86,10 @@ struct Polyhedron_tester : public Tester<K>
     std::vector<Initial_point> initial_points = { Initial_point{ Weighted_point(.5, .5, .5), 3, Index{}} };
     c3t3 = CGAL::make_mesh_3<C3t3>(domain, criteria, CGAL::parameters::initial_points(initial_points));
 
+    // test initial_points with a non-copyable range
+    Non_copyable_range_view initial_points_view{ initial_points };
+    c3t3 = CGAL::make_mesh_3<C3t3>(domain, criteria, CGAL::parameters::initial_points(initial_points_view));
+
     // test initial_points_generator with a generator generating tuple-like object
     auto initial_points_generator = [](auto oit, const int) {
       *oit++ = Initial_point{ Weighted_point(.5, .5, .5), 3, Index{} };
diff --git a/STL_Extension/include/CGAL/STL_Extension/internal/mesh_option_classes.h b/STL_Extension/include/CGAL/STL_Extension/internal/mesh_option_classes.h
index b017dac3111..6061a523675 100644
--- a/STL_Extension/include/CGAL/STL_Extension/internal/mesh_option_classes.h
+++ b/STL_Extension/include/CGAL/STL_Extension/internal/mesh_option_classes.h
@@ -196,8 +196,16 @@ struct Initialization_options
   using Initial_points_range
           = typename CGAL::Default::Get<InitialPointsRange, std::vector<Default_initial_point_type>>::type;
 
-  using Initial_points_const_iterator = typename Initial_points_range::const_iterator;
-  using Initial_point = typename std::iterator_traits<Initial_points_const_iterator>::value_type;
+  template <typename Range>
+  static auto cbegin(Range&& range) {
+    return std::cbegin(std::forward<Range>(range));
+  }
+
+  template <typename Range>
+  static auto cend(Range&& range) {
+    return std::cend(std::forward<Range>(range));
+  }
+  using Initial_points_const_iterator = decltype(cbegin(std::declval<Initial_points_range>()));
 
   Initialization_options()
   {}
@@ -205,8 +213,8 @@ struct Initialization_options
   Initialization_options(const Initial_points_generator& generator,
                          const Initial_points_range& initial_points)
     : initial_points_generator_(generator)
-    , begin_it(initial_points.begin())
-    , end_it(initial_points.end())
+    , begin_it(cbegin(initial_points))
+    , end_it(cend(initial_points))
   {}
 
   template<typename OutputIterator>