text: // Copyright (c) 2014  GeometryFactory (France). All rights reserved.
  //
  // This file is part of CGAL (www.cgal.org).
  // You can redistribute it and/or modify it under the terms of the GNU
  // General Public License as published by the Free Software Foundation,
  // either version 3 of the License, or (at your option) any later version.
  //
  // Licensees holding a valid commercial license may use this file in
  // accordance with the commercial license agreement provided with the software.
  //
  // This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
  // WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  //
  // $URL$
  // $Id$
  //
  // Author(s)     : Sebastien Loriot <sebastien.loriot@cgal.org>
  //
  #ifndef CGAL_SURFACE_MESH_SIMPLIFICATION_POLICIES_CONSTRAINED_PLACEMENT_H
  #define CGAL_SURFACE_MESH_SIMPLIFICATION_POLICIES_CONSTRAINED_PLACEMENT_H
  
  #include <CGAL/Surface_mesh_simplification/Detail/Common.h>
  #include <CGAL/Surface_mesh_simplification/Policies/Edge_collapse/Edge_profile.h>
  
  namespace CGAL {
  
  namespace Surface_mesh_simplification
  {
  
  template<class BasePlacement, class EdgeIsConstrainedMap>
  class Constrained_placement : public BasePlacement
  {
  public:
  
    EdgeIsConstrainedMap Edge_is_constrained_map;
  
  public:
    Constrained_placement(
      EdgeIsConstrainedMap map=EdgeIsConstrainedMap(),
      BasePlacement base=BasePlacement() )
    : BasePlacement(base)
    , Edge_is_constrained_map(map)
    {}
  
    template <typename Profile> 
    optional<typename Profile::Point> operator()( Profile const& aProfile ) const
    {
      typedef typename Profile::ECM                                ECM;
      typedef typename CGAL::Halfedge_around_target_iterator<ECM>  in_edge_iterator;
  
      in_edge_iterator eb, ee ;
      for ( boost::tie(eb,ee) = halfedges_around_target(aProfile.v0(),aProfile.surface_mesh());
        eb != ee ; ++ eb )
      {
        if( get(Edge_is_constrained_map, edge(*eb,aProfile.surface_mesh())) )
          return get(aProfile.vertex_point_map(),
                     aProfile.v0());
      }
      for ( boost::tie(eb,ee) = halfedges_around_target(aProfile.v1(),aProfile.surface_mesh());
        eb != ee ; ++ eb )
      {
        if( get(Edge_is_constrained_map, edge(*eb,aProfile.surface_mesh())) )
          return get(aProfile.vertex_point_map(),
                     aProfile.v1());
      }
  
      return static_cast<const BasePlacement*>(this)->operator()(aProfile);
    }
  };
  
  } // namespace Surface_mesh_simplification
  
  } //namespace CGAL
  
  #endif // CGAL_SURFACE_MESH_SIMPLIFICATION_POLICIES_CONSTRAINED_PLACEMENT_H
  