mirror of https://github.com/CGAL/cgal
91 lines
2.6 KiB
C++
91 lines
2.6 KiB
C++
#ifndef ONE_RING_ITERATORS_H
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#define ONE_RING_ITERATORS_H
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#include "Polyhedron_type.h"
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/***************************************************************/
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/* For iterating on one ring neighbor, sample usage:
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Halfedge_handle h; //or Vertex_handle or Facet_handle
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for(One_ring_iterator<Halfedge_handle> circ(h); circ; ++circ) {
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Halfedge_handle h_neighbor = circ;
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}
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*/
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template<class T>
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struct One_ring_iterator;
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template<>
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struct One_ring_iterator<Polyhedron::Vertex_handle> {
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One_ring_iterator(Polyhedron::Vertex_handle v)
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: circ(v->vertex_begin()), end(circ), first(true) { }
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operator bool() const { return first || circ != end; }
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operator Polyhedron::Vertex_handle() const { return circ->opposite()->vertex(); }
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One_ring_iterator& operator++() {
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first = false;
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++circ;
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return *this;
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}
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Polyhedron::Halfedge_around_vertex_circulator circ;
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Polyhedron::Halfedge_around_vertex_circulator end;
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bool first;
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// to be used in One_ring_iterator<Halfedge_handle>
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operator Polyhedron::Halfedge_handle() const {
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if ( &*circ < &*circ->opposite() ) return circ;
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return circ->opposite();
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}
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};
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template<>
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struct One_ring_iterator<Polyhedron::Facet_handle> {
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One_ring_iterator(Polyhedron::Facet_handle f)
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: circ(f->facet_begin()), end(circ), first(true)
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{
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iterate_to_non_border(); // move it to valid location
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}
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operator bool() const { return first || circ != end; }
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operator Polyhedron::Facet_handle() const {
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CGAL_assertion(!circ->opposite()->is_border());
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return circ->opposite()->facet();
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}
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One_ring_iterator& operator++() {
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first = false;
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++circ;
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if(circ != end) { iterate_to_non_border(); }
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return *this;
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}
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void iterate_to_non_border() {
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while(circ->opposite()->is_border()) {
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first = false;
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++circ;
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if(circ == end) { break; }
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}
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}
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Polyhedron::Halfedge_around_facet_circulator circ;
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Polyhedron::Halfedge_around_facet_circulator end;
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bool first;
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};
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template<>
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struct One_ring_iterator<boost::graph_traits<Polyhedron>::edge_descriptor> {
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One_ring_iterator(boost::graph_traits<Polyhedron>::edge_descriptor h)
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: it_1(h.halfedge()->vertex()), it_2(h.halfedge()->opposite()->vertex())
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{ }
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operator bool() const { return it_1 || it_2; }
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operator boost::graph_traits<Polyhedron>::edge_descriptor() const {
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Polyhedron tmp;
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if(it_1) { return edge(it_1, tmp); }
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return edge(it_2, tmp);
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}
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One_ring_iterator& operator++() {
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it_1 ? ++it_1 : ++it_2;
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return *this;
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}
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One_ring_iterator<Polyhedron::Vertex_handle> it_1;
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One_ring_iterator<Polyhedron::Vertex_handle> it_2;
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};
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#endif
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