dust3d/thirdparty/cgal/CGAL-5.1/include/CGAL/internal/boost/mutable_queue.hpp

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//
//=======================================================================
// Copyright 1997, 1998, 1999, 2000 University of Notre Dame.
// Authors: Andrew Lumsdaine, Lie-Quan Lee, Jeremy G. Siek
//
// Distributed under the Boost Software License, Version 1.0. (See
// accompanying file LICENSE_1_0.txt or copy at
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// https://www.boost.org/LICENSE_1_0.txt)
//=======================================================================
//
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// $URL: https://github.com/CGAL/cgal/blob/v5.1/STL_Extension/include/CGAL/internal/boost/mutable_queue.hpp $
// $Id: mutable_queue.hpp 590612a 2020-03-26T13:25:16+01:00 Sébastien Loriot
// SPDX-License-Identifier: BSL-1.0
//
// NOTE: this file have been taken from boost 1.46.1 for using
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// with Modificable_priority_queue (to enhance the
// non-documented mutable_queue).
// original file is <boost/pending/mutable_queue.hpp>
//
#ifndef CGAL_INTERNAL_BOOST_MUTABLE_QUEUE_HPP
#define CGAL_INTERNAL_BOOST_MUTABLE_QUEUE_HPP
#include <vector>
#include <algorithm>
#include <functional>
#include <CGAL/property_map.h>
#include <CGAL/internal/boost/mutable_heap.hpp>
#include <CGAL/internal/boost/array_binary_tree.hpp>
#include <iterator>
namespace CGAL { namespace internal {
namespace boost_ {
// The mutable queue whose elements are indexed
//
// This adaptor provides a special kind of priority queue that has
// and update operation. This allows the ordering of the items to
// change. After the ordering criteria for item x changes, one must
// call the Q.update(x)
//
// In order to efficiently find x in the queue, a functor must be
// provided to map value_type to a unique ID, which the
// mutable_queue will then use to map to the location of the
// item. The ID's generated must be between 0 and N, where N is the
// value passed to the constructor of mutable_queue
template <class IndexedType,
class RandomAccessContainer = std::vector<IndexedType>,
class Comp = std::less<typename RandomAccessContainer::value_type>,
class ID = ::boost::identity_property_map >
class mutable_queue {
public:
typedef IndexedType value_type;
typedef typename RandomAccessContainer::size_type size_type;
protected:
typedef typename RandomAccessContainer::iterator iterator;
#if !defined BOOST_NO_STD_ITERATOR_TRAITS
typedef array_binary_tree_node<iterator, ID> Node;
#else
typedef array_binary_tree_node<iterator, value_type, ID> Node;
#endif
typedef compare_array_node<RandomAccessContainer,Comp> Compare;
typedef std::vector<size_type> IndexArray;
public:
typedef Compare value_compare;
typedef ID id_generator;
mutable_queue(size_type n, const Comp& x, const ID& _id)
: index_array(n), comp(x), id(_id) {
c.reserve(n);
}
//SL: added this constructor so that index_array is filled with
// indices equals to n. Maintaining this property in pop allows
// to have a method to detect if an element is in the queue
mutable_queue(size_type n, const Comp& x, const ID& _id,bool)
: index_array(n,n), comp(x), id(_id) {
c.reserve(n);
}
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template <class ForwardIterator>
mutable_queue(ForwardIterator first, ForwardIterator last,
const Comp& x, const ID& _id)
: index_array(std::distance(first, last)), comp(x), id(_id)
{
while( first != last ) {
push(*first);
++first;
}
}
bool empty() const { return c.empty(); }
//SL: modified this function so that the element popped from the queue
// has its index set to the max number of element. That way we know
// that an element is not in the tree if its index is the max number
// of elements.
void pop() {
value_type tmp = c.back();
c.back() = c.front();
c.front() = tmp;
size_type id_f = get(id, c.back());
size_type id_b = get(id, tmp);
//SL was: size_type i = index_array[ id_b ];
index_array[ id_b ] = index_array[ id_f ];
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//SL was: index_array[ id_f ] = i;
index_array[ id_f ] = index_array.size(); /*SL added*/
c.pop_back();
Node node(c.begin(), c.end(), c.begin(), id);
down_heap(node, comp, index_array);
}
void push(const IndexedType& x) {
c.push_back(x);
/*set index-array*/
index_array[ get(id, x) ] = c.size()-1;
Node node(c.begin(), c.end(), c.end() - 1, id);
up_heap(node, comp, index_array);
}
void update(const IndexedType& x) {
size_type current_pos = index_array[ get(id, x) ];
c[current_pos] = x;
Node node(c.begin(), c.end(), c.begin()+current_pos, id);
update_heap(node, comp, index_array);
}
value_type& front() { return c.front(); }
value_type& top() { return c.front(); }
const value_type& front() const { return c.front(); }
const value_type& top() const { return c.front(); }
size_type size() const { return c.size(); }
void clear() { c.clear(); }
#if 0
// dwa 2003/7/11 - I don't know what compiler is supposed to
// be able to compile this, but is_heap is not standard!!
bool test() {
return std::is_heap(c.begin(), c.end(), Comp());
}
#endif
protected:
IndexArray index_array;
Compare comp;
RandomAccessContainer c;
ID id;
};
} } } //namespace CGAL::internal::boost_
#endif // CGAL_INTERNAL_BOOST_MUTABLE_QUEUE_HPP