add a way to check that only named parameters used by a function are …

…passed
sloriot · Jan 8, 2024 · 695246a · 695246a
1 parent 6df7424
commit 695246a
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diff --git a/STL_Extension/include/CGAL/Named_function_parameters.h b/STL_Extension/include/CGAL/Named_function_parameters.h
@@ -549,6 +549,64 @@ struct is_default_parameter
   typedef CGAL::Boolean_tag<value> type;
 };
 
+
+// code used to make sure all options passed are used by a function
+namespace authorized_parameters_impl
+{
+
+template <class ... Tag>
+struct Tag_wrapper{};
+
+template <class TagAllowed, class ... TagsAllowed, class Tag>
+constexpr
+bool is_tag_present(Tag_wrapper<TagAllowed, TagsAllowed...>, Tag)
+{
+  if (std::is_same_v<TagAllowed, Tag>)
+    return true;
+  else
+    return is_tag_present(Tag_wrapper<TagsAllowed...>(), Tag());
+}
+
+template <class Tag>
+constexpr
+bool is_tag_present(Tag_wrapper<Tag>, Tag)
+{
+  return true;
+}
+
+template <class TagAllowed, class Tag>
+constexpr
+bool is_tag_present(Tag_wrapper<TagAllowed>, Tag)
+{
+  return false;
+}
+
+template <class ... TagsAllowed, class T, class Tag>
+constexpr
+bool authorized_options_rec(const Named_function_parameters<T, Tag>&)
+{
+  return is_tag_present(Tag_wrapper<TagsAllowed...>(), Tag());
+}
+
+template <class ... TagsAllowed, class T, class Tag, class Base>
+constexpr
+bool authorized_options_rec(const Named_function_parameters<T, Tag, Base>& np)
+{
+  if (is_tag_present(Tag_wrapper<TagsAllowed...>(), Tag()))
+    return authorized_options_rec<TagsAllowed...>(static_cast<const Base&>(np));
+  return false;
+}
+
+}// impl namespace
+
+template <class ... TagsAllowed, class Named_function_parameters>
+constexpr
+bool authorized_options(const Named_function_parameters& np)
+{
+  return authorized_parameters_impl::authorized_options_rec
+    <internal_np::all_default_t, TagsAllowed...>(np);
+}
+
 } // end of parameters namespace
 
 #ifndef CGAL_NO_DEPRECATED_CODE

diff --git a/STL_Extension/test/STL_Extension/test_cgal_named_params.cpp b/STL_Extension/test/STL_Extension/test_cgal_named_params.cpp
@@ -89,6 +89,28 @@ void test_references(const NamedParameters& np)
   assert(&eim_ref==&default_value);
 }
 
+void test_authorized_options()
+{
+  auto np_ok1 = CGAL::parameters::vertex_point_map(0).edge_index_map(2).face_index_map(3);
+  auto np_ok2 = CGAL::parameters::face_index_map(3).vertex_point_map(0).edge_index_map(4);
+  auto np_ko = CGAL::parameters::face_index_map(3).vertex_point_map(0).edge_index_map(4).halfedge_index_map(4);
+  auto np_default = CGAL::parameters::default_values();
+
+
+  static_assert(CGAL::parameters::authorized_options<CGAL::internal_np::vertex_point_t,
+                                                     CGAL::internal_np::edge_index_t,
+                                                     CGAL::internal_np::face_index_t>(np_default));
+  static_assert(CGAL::parameters::authorized_options<CGAL::internal_np::vertex_point_t,
+                                                     CGAL::internal_np::edge_index_t,
+                                                     CGAL::internal_np::face_index_t>(np_ok1));
+  static_assert(CGAL::parameters::authorized_options<CGAL::internal_np::vertex_point_t,
+                                                     CGAL::internal_np::edge_index_t,
+                                                     CGAL::internal_np::face_index_t>(np_ok2));
+  static_assert(!CGAL::parameters::authorized_options<CGAL::internal_np::vertex_point_t,
+                                                      CGAL::internal_np::edge_index_t,
+                                                      CGAL::internal_np::face_index_t>(np_ko));
+}
+
 int main()
 {
   test_values_and_types(params::vertex_index_map(A<0>(0)).visitor(A<1>(1)));
@@ -111,5 +133,7 @@ int main()
   static_assert(std::is_same<decltype(d2),CGAL::parameters::Default_named_parameters>::value);
 #endif
 
+  test_authorized_options();
+
   return EXIT_SUCCESS;
 }