mirror of https://github.com/CGAL/cgal
102 lines
2.7 KiB
C++
102 lines
2.7 KiB
C++
#ifndef TRAVEL_ISOLATED_COMPONENTS_H
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#define TRAVEL_ISOLATED_COMPONENTS_H
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#include <boost/optional.hpp>
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#include <vector>
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#include "One_ring_iterators.h"
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#include <CGAL/Default.h>
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class Travel_isolated_components {
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public:
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// for transform iterator
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template<class HandleType>
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struct Get_handle {
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typedef HandleType result_type;
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template<class Iterator>
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result_type operator()(Iterator it) const
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{ return it; }
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};
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// to be used in get_minimum_isolated_component function
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struct Minimum_visitor
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{
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template<class HandleType>
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void operator()(const std::vector<HandleType>& C) {
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if(!minimum) { minimum = C.size(); }
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else { minimum = (std::min)(*minimum, C.size()); }
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}
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boost::optional<std::size_t> minimum;
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};
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// to be used in select_isolated_components function
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template<class OutputIterator>
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struct Selection_visitor
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{
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Selection_visitor(std::size_t threshold_size, OutputIterator out)
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: threshold_size(threshold_size), out(out), any_inserted(false) { }
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template<class HandleType>
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void operator()(const std::vector<HandleType>& C) {
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if(C.size() <= threshold_size) {
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any_inserted = true;
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out = std::copy(C.begin(), C.end(), out);
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}
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else {
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minimum_visitor(C);
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}
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}
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std::size_t threshold_size;
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OutputIterator out;
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bool any_inserted;
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Minimum_visitor minimum_visitor; // hold minimum of NOT inserted components
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};
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template <class Handle>
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std::size_t id(Handle h) { return h->id(); }
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std::size_t id(boost::graph_traits<Polyhedron>::edge_descriptor ed)
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{
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return ed.halfedge()->id() / 2;
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}
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// NOTE: prior to call this function, id fields should be updated
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template<class HandleType, class InputIterator, class IsSelected, class Visitor>
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void travel(InputIterator begin,
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InputIterator end,
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std::size_t size,
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const IsSelected& selection,
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Visitor& visitor)
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{
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std::vector<bool> mark(size, false);
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for(; begin != end; ++begin)
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{
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HandleType h = *begin;
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if(mark[id(h)] || selection.count(h)) { continue; }
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std::vector<HandleType> C;
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C.push_back(h);
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mark[id(h)] = true;
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std::size_t current_index = 0;
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bool neigh_to_selection = false;
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while(current_index < C.size()) {
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HandleType current = C[current_index++];
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for(One_ring_iterator<HandleType> circ(current); circ; ++circ)
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{
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HandleType nv = circ;
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neigh_to_selection |= (selection.count(nv)!=0);
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if(!mark[id(nv)] && !selection.count(nv)) {
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mark[id(nv)] = true;
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C.push_back(nv);
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}
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}
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}
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if(neigh_to_selection) { visitor(C); }
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}
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}
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};
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#endif
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