/usr/include/CGAL/halfedgeDS_cut_component.h is in libcgal-dev 4.7-4.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 | // Copyright (c) 1997
// Utrecht University (The Netherlands),
// ETH Zurich (Switzerland),
// INRIA Sophia-Antipolis (France),
// Max-Planck-Institute Saarbruecken (Germany),
// and Tel-Aviv University (Israel). 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 Lesser 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) : Lutz Kettner <kettner@mpi-sb.mpg.de>
// Cuts out a piece of a halfedge data structure defined by a predicate.
#ifndef CGAL_HALFEDGEDS_CUT_COMPONENT_H
#define CGAL_HALFEDGEDS_CUT_COMPONENT_H 1
#include <CGAL/basic.h>
#include <CGAL/HalfedgeDS_decorator.h>
namespace CGAL {
template < class HDS, class Predicate >
typename HDS::Halfedge_handle
halfedgeDS_cut_component( HDS& hds,
typename HDS::Halfedge_handle h,
Predicate pred,
typename HDS::Halfedge_handle& cut_piece)
// Cuts out a piece of a halfedge data structure for which the predicate
// `pred' is true for the vertices.
// The edge-vertex graph of the piece has to be a connected component.
// The remaining piece gets a new boundary. Returns a border halfedge of
// the new boundary on the remaining piece. Assigns a halfedge of the
// cut outpiece to `cut_piece'.
// The geometry for the vertices
// on the boundary and the hole have to be taken care of after this
// function call. The cut-out piece can be deleted with the member
// function erase_connected_component of the decorator class. It can
// technically happen that only an isolated vertex would remain in the
// cut out piece, in which case a dummy halfedge pair and vertex will be
// created to keep this vertex representable in the halfedge data structure.
// Precondition: pred( h->vertex()) && ! pred( h->opposite()->vertex()).
{
typedef typename HDS::Vertex_handle Vertex_handle;
typedef typename HDS::Halfedge_handle Halfedge_handle;
typedef typename HDS::Face_handle Face_handle;
typedef typename HDS::Vertex Vertex;
typedef typename HDS::Halfedge Halfedge;
typedef typename HDS::Face Face;
CGAL::HalfedgeDS_decorator<HDS> D(hds);
CGAL_precondition( D.is_valid(false,3));
CGAL_precondition( pred( h->vertex()));
CGAL_precondition( ! pred( h->opposite()->vertex()));
Halfedge_handle start = h;
Halfedge_handle hnew;
Halfedge_handle hlast;
while (true) {
// search re-entry point
Halfedge_handle g = h;
while ( pred( g->next()->vertex())) {
g = g->next();
// create border edges around cap
D.set_face( g, Face_handle());
}
if ( hnew == Halfedge_handle()) {
// first edge, special case
CGAL_assertion( g->next() != h && g->next()->opposite() != h);
Halfedge_handle gnext = g->next()->opposite();
D.remove_tip( g);
Vertex_handle v = D.vertices_push_back( Vertex());
D.close_tip( gnext, v);
hnew = hds.edges_push_back( Halfedge(), Halfedge());
hlast = hnew->opposite();
D.insert_tip( hlast, gnext);
D.set_face( hnew, D.get_face( gnext));
D.set_face_halfedge( hnew);
h = g;
D.set_vertex_halfedge( h);
} else { // general case and last case
Halfedge_handle gnext = g->next()->opposite();
if ( gnext == start && gnext == g) {
// last edge, special case of isolated vertex.
// Create dummy edge and dummy vertex and attach it to g
g = hds.edges_push_back( Halfedge(), Halfedge());
D.insert_tip( g, gnext);
D.close_tip(g->opposite(), D.vertices_push_back(Vertex()));
D.set_vertex_halfedge( g);
D.set_vertex_halfedge( g->opposite());
}
D.remove_tip( g);
Vertex_handle v = D.vertices_push_back( Vertex());
D.close_tip( hnew, v);
D.insert_tip( gnext, hnew);
hnew = hds.edges_push_back( Halfedge(), Halfedge());
D.insert_tip( hnew->opposite(), gnext);
D.set_face( hnew, D.get_face( gnext));
D.set_face_halfedge( hnew);
h = g;
D.set_vertex_halfedge( h);
if ( gnext == start) {
// last edge, special
D.insert_tip( hnew, hlast);
break;
}
}
} // while(true)
Face_handle fnew = D.faces_push_back( Face());
D.set_face_in_face_loop( hlast, fnew);
D.set_face_halfedge( hlast);
cut_piece = h;
CGAL_postcondition( D.is_valid(false,3));
return hlast;
}
template < class HDS, class Predicate >
typename HDS::Halfedge_handle
halfedgeDS_cut_component( HDS& hds,
typename HDS::Halfedge_handle h,
Predicate pred)
// Same function as above, but deletes the cut out piece immediately.
{
typedef typename HDS::Halfedge_handle Halfedge_handle;
CGAL::HalfedgeDS_decorator<HDS> D(hds);
CGAL_precondition( D.is_valid(false,3));
CGAL_precondition( pred( h->vertex()));
CGAL_precondition( ! pred( h->opposite()->vertex()));
Halfedge_handle cut_piece;
Halfedge_handle hnew = halfedgeDS_cut_component( hds, h, pred, cut_piece);
D.erase_connected_component( cut_piece);
CGAL_postcondition( D.is_valid(false,3));
return hnew;
}
} //namespace CGAL
#endif // CGAL_HALFEDGEDS_CUT_COMPONENT_H //
// EOF //
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