Using c++17 standard library (#7526)

use std::shared_ptr, std::optional, std::variant, ...

These are important changes since they appear in the CGAL API and thus
are breaking changes.

includes #7416

AABB_tree/doc/AABB_tree/Concepts/AABBGeomTraits.h

@@ -47,7 +47,7 @@ Provides the operator:
 `return_type operator()(const Query& q, const Primitive::Datum& d)`,
 
 which computes the intersection between `q` and `d`. The type of the returned object
-must be a `boost::optional` of a `boost::variant` of the possible intersection types.
+must be a `std::optional` of a `std::variant` of the possible intersection types.
 */
 typedef unspecified_type Intersect_3;
 

AABB_tree/doc/AABB_tree/Concepts/AABBRayIntersectionTraits.h

@@ -25,15 +25,15 @@ class AABBRayIntersectionTraits {
   /*!
     A functor object to compute the distance between the source of a ray and its
     closest intersection point between the ray and a primitive or a bounding box.
-    An empty `boost::optional` is returned, if there is no intersection.
+    An empty `std::optional` is returned, if there is no intersection.
     When there is an intersection, an object of type `FT` is returned such that
     if `i1` and `i2` are two intersection points, then `i1` is closer to the source
     of the ray than `i2` iff `n1 < n2`, `n1` and `n2` being the numbers returned for `i1` and `i2`
     respectively.
 
     Provides the operators:
-    `boost::optional<FT> operator()(const Ray_3& r, const Bounding_box& bbox)`.
-    `boost::optional<std::pair<FT, Intersection_and_primitive_id<Ray_3>::%Type > >
+    `std::optional<FT> operator()(const Ray_3& r, const Bounding_box& bbox)`.
+    `std::optional<std::pair<FT, Intersection_and_primitive_id<Ray_3>::%Type > >
      operator()(const Ray_3& r, const Primitive& primitive)`.
 
     A common algorithm to compute the intersection between a bounding box and a ray is <A

AABB_tree/doc/AABB_tree/Concepts/AABBTraits.h

@@ -119,10 +119,10 @@ typedef unspecified_type Do_intersect;
 
 /*!
 A functor object to compute the intersection of a query and a primitive. Provides the operator:
-`boost::optional<Intersection_and_primitive_id<Query>::%Type > operator()(const Query & q, const Primitive& primitive);` which returns the intersection as a pair composed of an object and a primitive id, iff the query intersects the primitive.
+`std::optional<Intersection_and_primitive_id<Query>::%Type > operator()(const Query & q, const Primitive& primitive);` which returns the intersection as a pair composed of an object and a primitive id, iff the query intersects the primitive.
 
 \cgalHeading{Note on Backward Compatibility}
-Before the release 4.3 of \cgal, the return type of this function used to be `boost::optional<Object_and_primitive_id>`.
+Before the release 4.3 of \cgal, the return type of this function used to be `std::optional<Object_and_primitive_id>`.
 */
 typedef unspecified_type Intersection;
 

AABB_tree/examples/AABB_tree/AABB_polyhedron_facet_intersection_example.cpp

@@ -19,8 +19,8 @@ typedef CGAL::Polyhedron_3<K> Polyhedron;
 typedef CGAL::AABB_face_graph_triangle_primitive<Polyhedron> Primitive;
 typedef CGAL::AABB_traits<K, Primitive> Traits;
 typedef CGAL::AABB_tree<Traits> Tree;
-typedef boost::optional< Tree::Intersection_and_primitive_id<Segment>::Type > Segment_intersection;
-typedef boost::optional< Tree::Intersection_and_primitive_id<Plane>::Type > Plane_intersection;
+typedef std::optional< Tree::Intersection_and_primitive_id<Segment>::Type > Segment_intersection;
+typedef std::optional< Tree::Intersection_and_primitive_id<Plane>::Type > Plane_intersection;
 typedef Tree::Primitive_id Primitive_id;
 
 int main()
@@ -57,7 +57,7 @@ int main()
     if(intersection)
     {
         // gets intersection object
-      const Point* p = boost::get<Point>(&(intersection->first));
+      const Point* p = std::get_if<Point>(&(intersection->first));
       if(p)
         std::cout << "intersection object is a point " << *p << std::endl;
 
@@ -81,7 +81,7 @@ int main()
     if(plane_intersection)
     {
 
-      if(boost::get<Segment>(&(plane_intersection->first)))
+      if(std::get_if<Segment>(&(plane_intersection->first)))
             std::cout << "intersection object is a segment" << std::endl;
     }
 

AABB_tree/examples/AABB_tree/AABB_ray_shooting_example.cpp

@@ -23,7 +23,7 @@ typedef boost::graph_traits<Mesh>::halfedge_descriptor halfedge_descriptor;
 typedef CGAL::AABB_face_graph_triangle_primitive<Mesh> Primitive;
 typedef CGAL::AABB_traits<K, Primitive> Traits;
 typedef CGAL::AABB_tree<Traits> Tree;
-typedef boost::optional<Tree::Intersection_and_primitive_id<Ray>::Type> Ray_intersection;
+typedef std::optional<Tree::Intersection_and_primitive_id<Ray>::Type> Ray_intersection;
 
 struct Skip
 {
@@ -70,8 +70,8 @@ int main(int argc, char* argv[])
     Ray_intersection intersection = tree.first_intersection(ray, skip);
     if(intersection)
     {
-      if(boost::get<Point>(&(intersection->first))){
-        const Point* p =  boost::get<Point>(&(intersection->first) );
+      if(std::get_if<Point>(&(intersection->first))){
+        const Point* p =  std::get_if<Point>(&(intersection->first) );
         std::cout <<  *p << std::endl;
       }
     }

AABB_tree/include/CGAL/AABB_traits.h

@@ -27,7 +27,7 @@
 #include <CGAL/Kernel_23/internal/Has_boolean_tags.h>
 
 
-#include <boost/optional.hpp>
+#include <optional>
 
 /// \file AABB_traits.h
 
@@ -39,7 +39,7 @@ template <class T>
 struct Remove_optional  { typedef T type; };
 
 template <class T>
-struct Remove_optional< ::boost::optional<T> >  { typedef T type; };
+struct Remove_optional< ::std::optional<T> >  { typedef T type; };
 
 //helper controlling whether extra data should be stored in the AABB_tree traits class
 template <class Primitive, bool has_shared_data=Has_nested_type_Shared_data<Primitive>::value>
@@ -85,7 +85,7 @@ struct AABB_traits_base_2<GeomTraits,true>{
   typedef typename CGAL::Bbox_3      Bounding_box;
 
   struct Intersection_distance {
-    boost::optional<FT> operator()(const Ray_3& ray, const Bounding_box& bbox) const {
+    std::optional<FT> operator()(const Ray_3& ray, const Bounding_box& bbox) const {
       FT t_near = -DBL_MAX; // std::numeric_limits<FT>::lowest(); C++1903
       FT t_far = DBL_MAX;
 
@@ -101,7 +101,7 @@ struct AABB_traits_base_2<GeomTraits,true>{
       for(int i = 0; i < 3; ++i, ++source_iter, ++direction_iter) {
         if(*direction_iter == 0) {
           if((*source_iter < (bbox.min)(i)) || (*source_iter > (bbox.max)(i))) {
-            return boost::none;
+            return std::nullopt;
           }
         } else {
           FT t1 = ((bbox.min)(i) - *source_iter) / *direction_iter;
@@ -118,7 +118,7 @@ struct AABB_traits_base_2<GeomTraits,true>{
           //   t_far = t2;
 
           if(t_near > t_far || t_far < FT(0.))
-            return boost::none;
+            return std::nullopt;
         }
       }
 
@@ -193,7 +193,7 @@ class AABB_traits
 
   /// `Intersection_and_primitive_id<Query>::%Type::first_type` is found according to
   /// the result type of `GeomTraits::Intersect_3::operator()`. If it is
-  /// `boost::optional<T>` then it is `T`, and the result type otherwise.
+  /// `std::optional<T>` then it is `T`, and the result type otherwise.
   template<typename Query>
   struct Intersection_and_primitive_id {
     typedef decltype(
@@ -364,12 +364,12 @@ class AABB_traits
     Intersection(const AABB_traits<GeomTraits,AABBPrimitive,BboxMap>& traits)
       :m_traits(traits) {}
     template<typename Query>
-    boost::optional< typename Intersection_and_primitive_id<Query>::Type >
+    std::optional< typename Intersection_and_primitive_id<Query>::Type >
     operator()(const Query& query, const typename AT::Primitive& primitive) const {
       auto inter_res = GeomTraits().intersect_3_object()(query, internal::Primitive_helper<AT>::get_datum(primitive,m_traits));
       if (!inter_res)
-        return boost::none;
-      return boost::make_optional( std::make_pair(*inter_res, primitive.id()) );
+        return std::nullopt;
+      return std::make_optional( std::make_pair(*inter_res, primitive.id()) );
     }
   };
 

AABB_tree/include/CGAL/AABB_tree.h

@@ -26,7 +26,7 @@
 #include <CGAL/AABB_tree/internal/AABB_search_tree.h>
 #include <CGAL/AABB_tree/internal/Has_nested_type_Shared_data.h>
 #include <CGAL/AABB_tree/internal/Primitive_helper.h>
-#include <boost/optional.hpp>
+#include <optional>
 
 #ifdef CGAL_HAS_THREADS
 #include <CGAL/mutex.h>
@@ -270,7 +270,7 @@ namespace CGAL {
     /// \tparam Query must be a type for which `Do_intersect` operators are
     ///               defined in the traits class `AABBTraits`.
     template <typename Query>
-    boost::optional<Primitive_id> any_intersected_primitive(const Query& query) const;
+    std::optional<Primitive_id> any_intersected_primitive(const Query& query) const;
     ///@}
 
     /// \name Intersections
@@ -293,7 +293,7 @@ namespace CGAL {
     /// \tparam Query must be a type for which `Do_intersect` and `Intersection` operators are
     ///               defined in the traits class `AABBTraits`.
     template <typename Query>
-    boost::optional< typename Intersection_and_primitive_id<Query>::Type >
+    std::optional< typename Intersection_and_primitive_id<Query>::Type >
     any_intersection(const Query& query) const;
 
 
@@ -317,12 +317,12 @@ namespace CGAL {
     /// `AABBTraits` must be a model of `AABBRayIntersectionTraits` to
     /// call this member function.
     template<typename Ray, typename SkipFunctor>
-    boost::optional< typename Intersection_and_primitive_id<Ray>::Type >
+    std::optional< typename Intersection_and_primitive_id<Ray>::Type >
     first_intersection(const Ray& query, const SkipFunctor& skip) const;
 
     /// \cond
     template<typename Ray>
-    boost::optional< typename Intersection_and_primitive_id<Ray>::Type >
+    std::optional< typename Intersection_and_primitive_id<Ray>::Type >
     first_intersection(const Ray& query) const
     {
       return first_intersection(query, [](Primitive_id){ return false; });
@@ -342,12 +342,12 @@ namespace CGAL {
     /// `AABBTraits` must be a model of `AABBRayIntersectionTraits` to
     /// call this member function.
     template<typename Ray, typename SkipFunctor>
-    boost::optional<Primitive_id>
+    std::optional<Primitive_id>
     first_intersected_primitive(const Ray& query, const SkipFunctor& skip) const;
 
     /// \cond
     template<typename Ray>
-    boost::optional<Primitive_id>
+    std::optional<Primitive_id>
     first_intersected_primitive(const Ray& query) const
     {
       return first_intersected_primitive(query, [](Primitive_id){ return false; });
@@ -963,7 +963,7 @@ namespace CGAL {
 
   template <typename Tr>
   template <typename Query>
-  boost::optional< typename AABB_tree<Tr>::template Intersection_and_primitive_id<Query>::Type >
+  std::optional< typename AABB_tree<Tr>::template Intersection_and_primitive_id<Query>::Type >
     AABB_tree<Tr>::any_intersection(const Query& query) const
   {
     using namespace CGAL::internal::AABB_tree;
@@ -975,7 +975,7 @@ namespace CGAL {
 
   template <typename Tr>
   template <typename Query>
-  boost::optional<typename AABB_tree<Tr>::Primitive_id>
+  std::optional<typename AABB_tree<Tr>::Primitive_id>
     AABB_tree<Tr>::any_intersected_primitive(const Query& query) const
   {
     using namespace CGAL::internal::AABB_tree;

AABB_tree/include/CGAL/AABB_tree/internal/AABB_ray_intersection.h

@@ -19,8 +19,7 @@
 
 #include <functional>
 #include <type_traits>
-#include <boost/optional.hpp>
-#include <boost/variant/apply_visitor.hpp>
+#include <optional>
 #  if defined(BOOST_MSVC)
 #    pragma warning(push)
 #    pragma warning(disable: 4996)
@@ -43,7 +42,7 @@ class AABB_ray_intersection {
 public:
   AABB_ray_intersection(const AABBTree& tree) : tree_(tree) {}
 
-  boost::optional< Ray_intersection_and_primitive_id >
+  std::optional< Ray_intersection_and_primitive_id >
   ray_intersection(const Ray& query, SkipFunctor skip) const {
     // We hit the root, now continue on the children. Keep track of
     // nb_primitives through a variable in each Node on the stack. In
@@ -63,7 +62,7 @@ class AABB_ray_intersection {
 
     Heap_type pq;
     // pq.reserve(tree_.size() / 2);
-    boost::optional< Ray_intersection_and_primitive_id >
+    std::optional< Ray_intersection_and_primitive_id >
       intersection, /* the temporary for calculating the result */
       p; /* the current best intersection */
 
@@ -84,7 +83,7 @@ class AABB_ray_intersection {
         if(!skip(current.node->left_data().id()) /* && do_intersect_obj(query, current.node->left_data()) */) {
           intersection = intersection_obj(query, current.node->left_data());
           if(intersection) {
-            FT ray_distance = boost::apply_visitor(param_visitor, intersection->first);
+            FT ray_distance = std::visit(param_visitor, intersection->first);
             if(ray_distance < t) {
               t = ray_distance;
               p = intersection;
@@ -96,7 +95,7 @@ class AABB_ray_intersection {
         if(!skip(current.node->right_data().id()) /* && do_intersect_obj(query, current.node->right_data()) */) {
           intersection = intersection_obj(query, current.node->right_data());
           if(intersection) {
-            FT ray_distance = boost::apply_visitor(param_visitor, intersection->first);
+            FT ray_distance = std::visit(param_visitor, intersection->first);
             if(ray_distance < t) {
               t = ray_distance;
               p = intersection;
@@ -111,7 +110,7 @@ class AABB_ray_intersection {
         if(!skip(current.node->left_data().id()) /* && do_intersect_obj(query, current.node->left_data()) */) {
           intersection = intersection_obj(query, current.node->left_data());
           if(intersection) {
-            FT ray_distance = boost::apply_visitor(param_visitor, intersection->first);
+            FT ray_distance = std::visit(param_visitor, intersection->first);
             if(ray_distance < t) {
               t = ray_distance;
               p = intersection;
@@ -121,7 +120,7 @@ class AABB_ray_intersection {
 
         // right child
         const Node* child = &(current.node->right_child());
-        boost::optional< FT > dist = intersection_distance_obj(query, child->bbox());
+        std::optional< FT > dist = intersection_distance_obj(query, child->bbox());
         if(dist)
           pq.push(Node_ptr_with_ft(child, *dist, 2));
 
@@ -130,7 +129,7 @@ class AABB_ray_intersection {
       default: // Children both inner nodes
       {
         const Node* child = &(current.node->left_child());
-        boost::optional<FT> dist = intersection_distance_obj(query, child->bbox());
+        std::optional<FT> dist = intersection_distance_obj(query, child->bbox());
         if(dist)
           pq.push(Node_ptr_with_ft(child, *dist, current.nb_primitives/2));
 
@@ -198,7 +197,7 @@ class AABB_ray_intersection {
 
 template<typename AABBTraits>
 template<typename Ray, typename SkipFunctor>
-boost::optional< typename AABB_tree<AABBTraits>::template Intersection_and_primitive_id<Ray>::Type >
+std::optional< typename AABB_tree<AABBTraits>::template Intersection_and_primitive_id<Ray>::Type >
 AABB_tree<AABBTraits>::first_intersection(const Ray& query,
                                           const SkipFunctor& skip) const {
   static_assert(std::is_same<Ray, typename AABBTraits::Ray_3>::value,
@@ -219,22 +218,22 @@ AABB_tree<AABBTraits>::first_intersection(const Ray& query,
       break;
     }
   }
-  return boost::none;
+  return std::nullopt;
 }
 
 template<typename AABBTraits>
 template<typename Ray, typename SkipFunctor>
-boost::optional<typename AABB_tree<AABBTraits>::Primitive_id>
+std::optional<typename AABB_tree<AABBTraits>::Primitive_id>
 AABB_tree<AABBTraits>::first_intersected_primitive(const Ray& query,
                             const SkipFunctor& skip) const
 {
-  boost::optional<
+  std::optional<
     typename AABB_tree<AABBTraits>::
       template Intersection_and_primitive_id<Ray>::Type > res =
         first_intersection(query, skip);
   if ( (bool) res )
-    return boost::make_optional( res->second );
-  return boost::none;
+    return std::make_optional( res->second );
+  return std::nullopt;
 }
 
 }

AABB_tree/include/CGAL/AABB_tree/internal/AABB_traversal_traits.h

@@ -17,7 +17,7 @@
 
 
 #include <CGAL/AABB_tree/internal/AABB_node.h>
-#include <boost/optional.hpp>
+#include <optional>
 
 namespace CGAL {
 
@@ -69,7 +69,7 @@ class First_intersection_traits
 
 public:
   typedef
-  boost::optional< typename AABBTraits::template Intersection_and_primitive_id<Query>::Type >
+  std::optional< typename AABBTraits::template Intersection_and_primitive_id<Query>::Type >
   Result;
 public:
   First_intersection_traits(const AABBTraits& traits)
@@ -124,7 +124,7 @@ class Listing_intersection_traits
 
   void intersection(const Query& query, const Primitive& primitive)
   {
-    boost::optional< typename AABBTraits::template Intersection_and_primitive_id<Query>::Type >
+    std::optional< typename AABBTraits::template Intersection_and_primitive_id<Query>::Type >
     intersection = m_traits.intersection_object()(query, primitive);
 
     if(intersection)
@@ -211,7 +211,7 @@ class First_primitive_traits
   {
     if( m_traits.do_intersect_object()(query, primitive) )
     {
-      m_result = boost::optional<typename Primitive::Id>(primitive.id());
+      m_result = std::optional<typename Primitive::Id>(primitive.id());
       m_is_found = true;
     }
   }
@@ -221,12 +221,12 @@ class First_primitive_traits
     return m_traits.do_intersect_object()(query, node.bbox());
   }
 
-  boost::optional<typename Primitive::Id> result() const { return m_result; }
+  std::optional<typename Primitive::Id> result() const { return m_result; }
   bool is_intersection_found() const { return m_is_found; }
 
 private:
   bool m_is_found;
-  boost::optional<typename Primitive::Id> m_result;
+  std::optional<typename Primitive::Id> m_result;
   const AABBTraits& m_traits;
 };