2 //=======================================================================
3 // Copyright 1997, 1998, 1999, 2000 University of Notre Dame.
4 // Authors: Andrew Lumsdaine, Lie-Quan Lee, Jeremy G. Siek
6 // Distributed under the Boost Software License, Version 1.0. (See
7 // accompanying file LICENSE_1_0.txt or copy at
8 // http://www.boost.org/LICENSE_1_0.txt)
9 //=======================================================================
11 #ifndef BOOST_MUTABLE_QUEUE_HPP
12 #define BOOST_MUTABLE_QUEUE_HPP
17 #include <boost/property_map.hpp>
18 #include <boost/pending/mutable_heap.hpp>
19 #include <boost/pending/is_heap.hpp>
20 #include <boost/graph/detail/array_binary_tree.hpp>
25 // The mutable queue whose elements are indexed
27 // This adaptor provides a special kind of priority queue that has
28 // and update operation. This allows the ordering of the items to
29 // change. After the ordering criteria for item x changes, one must
30 // call the Q.update(x)
32 // In order to efficiently find x in the queue, a functor must be
33 // provided to map value_type to a unique ID, which the
34 // mutable_queue will then use to map to the location of the
35 // item. The ID's generated must be between 0 and N, where N is the
36 // value passed to the constructor of mutable_queue
38 template <class IndexedType,
39 class RandomAccessContainer = std::vector<IndexedType>,
40 class Comp = std::less<typename RandomAccessContainer::value_type>,
41 class ID = identity_property_map >
44 typedef IndexedType value_type;
45 typedef typename RandomAccessContainer::size_type size_type;
47 typedef typename RandomAccessContainer::iterator iterator;
48 #if !defined BOOST_NO_STD_ITERATOR_TRAITS
49 typedef adstl::array_binary_tree_node<iterator, ID> Node;
51 typedef adstl::array_binary_tree_node<iterator, value_type, ID> Node;
53 typedef adstl::compare_array_node<RandomAccessContainer,Comp> Compare;
54 typedef std::vector<size_type> IndexArray;
56 typedef Compare value_compare;
57 typedef ID id_generator;
59 mutable_queue(size_type n, const Comp& x, const ID& _id)
60 : index_array(n), comp(x), id(_id) {
63 template <class ForwardIterator>
64 mutable_queue(ForwardIterator first, ForwardIterator last,
65 const Comp& x, const ID& _id)
66 : index_array(std::distance(first, last)), comp(x), id(_id)
68 while( first != last ) {
74 bool empty() const { return c.empty(); }
77 value_type tmp = c.back();
81 size_type id_f = get(id, c.back());
82 size_type id_b = get(id, tmp);
83 size_type i = index_array[ id_b ];
84 index_array[ id_b ] = index_array[ id_f ];
85 index_array[ id_f ] = i;
88 Node node(c.begin(), c.end(), c.begin(), id);
89 down_heap(node, comp, index_array);
91 void push(const IndexedType& x) {
94 index_array[ get(id, x) ] = c.size()-1;
95 Node node(c.begin(), c.end(), c.end() - 1, id);
96 up_heap(node, comp, index_array);
99 void update(const IndexedType& x) {
100 size_type current_pos = index_array[ get(id, x) ];
103 Node node(c.begin(), c.end(), c.begin()+current_pos, id);
104 update_heap(node, comp, index_array);
107 value_type& front() { return c.front(); }
108 value_type& top() { return c.front(); }
110 const value_type& front() const { return c.front(); }
111 const value_type& top() const { return c.front(); }
113 size_type size() const { return c.size(); }
115 void clear() { c.clear(); }
118 // dwa 2003/7/11 - I don't know what compiler is supposed to
119 // be able to compile this, but is_heap is not standard!!
121 return std::is_heap(c.begin(), c.end(), Comp());
126 IndexArray index_array;
128 RandomAccessContainer c;
135 #endif // BOOST_MUTABLE_QUEUE_HPP