graph/include/boost/pending/mutable_queue.hpp
K. Noel Belcourt 7f94230dca Revert "removed an unused function (#39)"
This reverts commit 655ce30eb3.
2016-07-16 16:16:59 -06:00

136 lines
4.1 KiB
C++

//
//=======================================================================
// 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
// http://www.boost.org/LICENSE_1_0.txt)
//=======================================================================
//
#ifndef BOOST_MUTABLE_QUEUE_HPP
#define BOOST_MUTABLE_QUEUE_HPP
#include <vector>
#include <algorithm>
#include <functional>
#include <boost/property_map/property_map.hpp>
#include <boost/pending/mutable_heap.hpp>
#include <boost/pending/is_heap.hpp>
#include <boost/graph/detail/array_binary_tree.hpp>
#include <iterator>
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 = 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);
}
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(); }
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);
size_type i = index_array[ id_b ];
index_array[ id_b ] = index_array[ id_f ];
index_array[ id_f ] = i;
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;
};
}
#endif // BOOST_MUTABLE_QUEUE_HPP