text: // Copyright (c) 1999-2006  INRIA Sophia-Antipolis (France).
  // All rights reserved.
  //
  // This file is part of CGAL (www.cgal.org).
  //
  // $URL$
  // $Id$
  // SPDX-License-Identifier: GPL-3.0-or-later OR LicenseRef-Commercial
  //
  // Author(s)     : Monique Teillaud <Monique.Teillaud@sophia.inria.fr>
  //                 Sylvain Pion
  
  // cell of a triangulation of any dimension <=3,
  // storing its circumcenter lazily.
  
  #ifndef CGAL_REGULAR_TRIANGULATION_CELL_BASE_WITH_CIRCUMCENTER_3_H
  #define CGAL_REGULAR_TRIANGULATION_CELL_BASE_WITH_CIRCUMCENTER_3_H
  
  #include <CGAL/license/Triangulation_3.h>
  
  #include <CGAL/basic.h>
  #include <CGAL/triangulation_assertions.h>
  #include <CGAL/Regular_triangulation_cell_base_3.h>
  
  #include <boost/mpl/if.hpp>
  #include <boost/mpl/identity.hpp>
  
  namespace CGAL {
  
  template < typename GT, typename Cb = Regular_triangulation_cell_base_3<GT> >
  class Regular_triangulation_cell_base_with_weighted_circumcenter_3
    : public Cb
  {
    typedef typename GT::Point_3                Point_3;
    typedef typename GT::Weighted_point_3       Point;
  
    mutable Point_3* weighted_circumcenter_;
  
  public:
    void invalidate_weighted_circumcenter_cache()
    {
        if (weighted_circumcenter_) {
            delete weighted_circumcenter_;
            weighted_circumcenter_ = nullptr;
        }
    }
  
  public:
    typedef typename Cb::Vertex_handle                   Vertex_handle;
    typedef typename Cb::Cell_handle                     Cell_handle;
  
    typedef GT                                           Geom_traits;
  
    template < typename TDS2 >
    struct Rebind_TDS {
      typedef typename Cb::template Rebind_TDS<TDS2>::Other         Cb2;
      typedef
        Regular_triangulation_cell_base_with_weighted_circumcenter_3<GT, Cb2>
        Other;
    };
  
    Regular_triangulation_cell_base_with_weighted_circumcenter_3()
      : Cb(), weighted_circumcenter_(nullptr) {}
  
    Regular_triangulation_cell_base_with_weighted_circumcenter_3
          (const Regular_triangulation_cell_base_with_weighted_circumcenter_3 &c)
      : Cb(c),
        weighted_circumcenter_(c.weighted_circumcenter_ != nullptr ?
                               new Point_3(*(c.weighted_circumcenter_)) :
                               nullptr)
    {}
  
    Regular_triangulation_cell_base_with_weighted_circumcenter_3&
    operator=
      (const Regular_triangulation_cell_base_with_weighted_circumcenter_3 &c)
    {
        Regular_triangulation_cell_base_with_weighted_circumcenter_3 tmp=c;
        tmp.swap(*this);
        return *this;
    }
  
    Regular_triangulation_cell_base_with_weighted_circumcenter_3(
                              Vertex_handle v0, Vertex_handle v1,
                              Vertex_handle v2, Vertex_handle v3)
      : Cb(v0, v1, v2, v3), weighted_circumcenter_(nullptr) {}
  
    Regular_triangulation_cell_base_with_weighted_circumcenter_3(
                              Vertex_handle v0, Vertex_handle v1,
                              Vertex_handle v2, Vertex_handle v3,
                              Cell_handle   n0, Cell_handle   n1,
                              Cell_handle   n2, Cell_handle   n3)
      : Cb(v0, v1, v2, v3, n0, n1, n2, n3), weighted_circumcenter_(nullptr) {}
  
    ~Regular_triangulation_cell_base_with_weighted_circumcenter_3()
    {
        delete weighted_circumcenter_;
    }
  
    // We must override the functions that modify the vertices.
    // And if the point inside a vertex is modified, we fail,
    // but there's not much we can do for this now.
    void set_vertex(int i, Vertex_handle v)
    {
        invalidate_weighted_circumcenter_cache();
        Cb::set_vertex(i, v);
    }
  
    void set_vertices()
    {
        invalidate_weighted_circumcenter_cache();
        Cb::set_vertices();
    }
  
    void set_vertices(Vertex_handle v0, Vertex_handle v1,
                      Vertex_handle v2, Vertex_handle v3)
    {
        invalidate_weighted_circumcenter_cache();
        Cb::set_vertices(v0, v1, v2, v3);
    }
  
    const Point_3 &
    weighted_circumcenter(const Geom_traits& gt = Geom_traits()) const
    {
        if (weighted_circumcenter_ == nullptr) {
                weighted_circumcenter_
              = new Point_3(this->Cb::weighted_circumcenter(gt));
        } else {
          CGAL_expensive_assertion(
            this->Cb::weighted_circumcenter(gt) == *weighted_circumcenter_);
        }
  
        return *weighted_circumcenter_;
    }
  
    void swap (Regular_triangulation_cell_base_with_weighted_circumcenter_3& other) noexcept
    {
      std::swap(static_cast<Cb&>(*this), static_cast<Cb&>(other));
      std::swap(weighted_circumcenter_, other.weighted_circumcenter_);
    }
  };
  
  } //namespace CGAL
  
  #endif // CGAL_REGULAR_TRIANGULATION_CELL_BASE_WITH_CIRCUMCENTER_3_H
  