// ============================================================================
//
// Copyright (c) 1997 The CGAL Consortium
//
// This software and related documentation is part of an INTERNAL release
// of the Computational Geometry Algorithms Library (CGAL). It is not
// intended for general use.
//
// ----------------------------------------------------------------------------
//
// release       : $CGAL_Revision: $
// release_date  : $CGAL_Date: $
//
// file          : include/CGAL/HalfedgeDS_halfedge_min_base.h
// package       : HalfedgeDS 3.3 (27 Sep 2000)
// chapter       : Halfedge Data Structures
//
// revision      : $Revision$
// revision_date : $Date$
//
// author(s)     : Lutz Kettner  <kettner@mpi-sb.mpg.de>
// maintainer    :
// coordinator   : MPI Saarbruecken
//
// Halfedge Data Structure Minimal Base Class for Vertices.
// ============================================================================

#ifndef CGAL_HALFEDGEDS_HALFEDGE_MIN_BASE_H
#define CGAL_HALFEDGEDS_HALFEDGE_MIN_BASE_H 1

#ifndef CGAL_BASIC_H
#include <CGAL/basic.h>
#endif

CGAL_BEGIN_NAMESPACE

template < class Refs>
struct HalfedgeDS_halfedge_min_base_base {
    // Base_base will be used to access set_opposite(), which is
    // made private in the normal halfedge bases. Since halfedges
    // come always in pairs, managed by the HDS, the set_opposite()
    // member function is protected from the user.
    typedef Refs                                 HalfedgeDS;
    typedef HalfedgeDS_halfedge_min_base_base<Refs> Base_base;
    typedef Tag_false                            Supports_halfedge_prev;
    typedef Tag_false                            Supports_halfedge_vertex;
    typedef Tag_false                            Supports_halfedge_face;
    typedef typename Refs::Vertex_handle         Vertex_handle;
    typedef typename Refs::Vertex_const_handle   Vertex_const_handle;
    typedef typename Refs::Halfedge_handle       Halfedge_handle;
    typedef typename Refs::Halfedge_const_handle Halfedge_const_handle;
    typedef typename Refs::Face_handle           Face_handle;
    typedef typename Refs::Face_const_handle     Face_const_handle;
    typedef typename Refs::Vertex                Vertex;
    typedef typename Refs::Face                  Face;
private:
    Halfedge_handle  opp;
    Halfedge_handle  nxt;
public:
    Halfedge_handle       opposite()                        { return opp;}
    Halfedge_const_handle opposite() const                  { return opp;}
    void                  set_opposite( Halfedge_handle h)  { opp = h;}
    Halfedge_handle       next()                            { return nxt;}
    Halfedge_const_handle next() const                      { return nxt;}
    void                  set_next( Halfedge_handle h)      { nxt = h;}

    bool is_border() const { return false;}
        // is always false as long as faces are not supported.
};

template < class Refs>
class HalfedgeDS_halfedge_min_base
    : public HalfedgeDS_halfedge_min_base_base< Refs>
{
public:
    typedef typename Refs::Halfedge_handle Halfedge_handle;
    typedef HalfedgeDS_halfedge_min_base<Refs>       Base;
    typedef HalfedgeDS_halfedge_min_base_base<Refs>  Base_base;
private:
    void  set_opposite( Halfedge_handle h)  { Base_base::set_opposite(h);}
};

CGAL_END_NAMESPACE

#endif // CGAL_HALFEDGEDS_HALFEDGE_MIN_BASE_H //
// EOF //