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/* This file is part of the Gudhi Library. The Gudhi library
* (Geometric Understanding in Higher Dimensions) is a generic C++
* library for computational topology.
*
* Author(s): Siargey Kachanovich
*
* Copyright (C) 2016 Inria
*
* Modification(s):
* - YYYY/MM Author: Description of the modification
*/
#ifndef ACTIVE_WITNESS_ACTIVE_WITNESS_ITERATOR_H_
#define ACTIVE_WITNESS_ACTIVE_WITNESS_ITERATOR_H_
#include <boost/iterator/iterator_facade.hpp>
#include <list>
namespace Gudhi {
namespace witness_complex {
/* \brief Iterator in the nearest landmark list.
* \details After the iterator reaches the end of the list,
* the list is augmented by a (nearest landmark, distance) pair if possible.
* If all the landmarks are present in the list, iterator returns the specific end value
* of the corresponding 'Active_witness' object.
*/
template< typename Active_witness,
typename Id_distance_pair,
typename INS_iterator >
class Active_witness_iterator
: public boost::iterator_facade< Active_witness_iterator <Active_witness, Id_distance_pair, INS_iterator>,
Id_distance_pair const,
boost::forward_traversal_tag,
Id_distance_pair const> {
friend class boost::iterator_core_access;
typedef typename std::list<Id_distance_pair>::iterator Pair_iterator;
typedef typename Gudhi::witness_complex::Active_witness_iterator<Active_witness,
Id_distance_pair,
INS_iterator> Iterator;
Active_witness *aw_;
Pair_iterator lh_; // landmark handle
bool is_end_; // true only if the pointer is end and there are no more neighbors to add
public:
Active_witness_iterator(Active_witness* aw)
: aw_(aw), lh_(aw_->nearest_landmark_table_.end()), is_end_(true) {
}
Active_witness_iterator(Active_witness* aw, const Pair_iterator& lh)
: aw_(aw), lh_(lh) {
is_end_ = false;
if (lh_ == aw_->nearest_landmark_table_.end()) {
if (aw_->iterator_next_ == aw_->iterator_end_) {
is_end_ = true;
} else {
aw_->nearest_landmark_table_.push_back(*aw_->iterator_next_);
lh_ = --aw_->nearest_landmark_table_.end();
++(aw_->iterator_next_);
}
}
}
private :
Id_distance_pair& dereference() const {
return *lh_;
}
bool equal(const Iterator& other) const {
return (is_end_ == other.is_end_) || (lh_ == other.lh_);
}
void increment() {
// the neighbor search can't be at the end iterator of a list
GUDHI_CHECK(!is_end_ && lh_ != aw_->nearest_landmark_table_.end(),
std::logic_error("Wrong active witness increment."));
// if the id of the current landmark is the same as the last one
lh_++;
if (lh_ == aw_->nearest_landmark_table_.end()) {
if (aw_->iterator_next_ == aw_->iterator_end_) {
is_end_ = true;
} else {
aw_->nearest_landmark_table_.push_back(*aw_->iterator_next_);
lh_ = std::prev(aw_->nearest_landmark_table_.end());
++(aw_->iterator_next_);
}
}
}
};
} // namespace witness_complex
} // namespace Gudhi
#endif // ACTIVE_WITNESS_ACTIVE_WITNESS_ITERATOR_H_
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