1 // 2 //======================================================================= 3 // Copyright 1997, 1998, 1999, 2000 University of Notre Dame. 4 // Authors: Andrew Lumsdaine, Lie-Quan Lee, Jeremy G. Siek 5 // 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 //======================================================================= 10 // 11 #ifndef BOOST_MUTABLE_QUEUE_HPP 12 #define BOOST_MUTABLE_QUEUE_HPP 13 14 #include <vector> 15 #include <algorithm> 16 #include <functional> 17 #include <boost/property_map/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> 21 #include <iterator> 22 23 namespace boost { 24 25 // The mutable queue whose elements are indexed 26 // 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) 31 // 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 37 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 > 42 class mutable_queue { 43 public: 44 typedef IndexedType value_type; 45 typedef typename RandomAccessContainer::size_type size_type; 46 protected: 47 typedef typename RandomAccessContainer::iterator iterator; 48 #if !defined BOOST_NO_STD_ITERATOR_TRAITS 49 typedef array_binary_tree_node<iterator, ID> Node; 50 #else 51 typedef array_binary_tree_node<iterator, value_type, ID> Node; 52 #endif 53 typedef compare_array_node<RandomAccessContainer,Comp> Compare; 54 typedef std::vector<size_type> IndexArray; 55 public: 56 typedef Compare value_compare; 57 typedef ID id_generator; 58 mutable_queue(size_type n,const Comp & x,const ID & _id)59 mutable_queue(size_type n, const Comp& x, const ID& _id) 60 : index_array(n), comp(x), id(_id) { 61 c.reserve(n); 62 } 63 template <class ForwardIterator> mutable_queue(ForwardIterator first,ForwardIterator last,const Comp & x,const ID & _id)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) 67 { 68 while( first != last ) { 69 push(*first); 70 ++first; 71 } 72 } 73 empty() const74 bool empty() const { return c.empty(); } 75 pop()76 void pop() { 77 value_type tmp = c.back(); 78 c.back() = c.front(); 79 c.front() = tmp; 80 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; 86 87 c.pop_back(); 88 Node node(c.begin(), c.end(), c.begin(), id); 89 down_heap(node, comp, index_array); 90 } push(const IndexedType & x)91 void push(const IndexedType& x) { 92 c.push_back(x); 93 /*set index-array*/ 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); 97 } 98 update(const IndexedType & x)99 void update(const IndexedType& x) { 100 size_type current_pos = index_array[ get(id, x) ]; 101 c[current_pos] = x; 102 103 Node node(c.begin(), c.end(), c.begin()+current_pos, id); 104 update_heap(node, comp, index_array); 105 } 106 front()107 value_type& front() { return c.front(); } top()108 value_type& top() { return c.front(); } 109 front() const110 const value_type& front() const { return c.front(); } top() const111 const value_type& top() const { return c.front(); } 112 size() const113 size_type size() const { return c.size(); } 114 clear()115 void clear() { c.clear(); } 116 117 #if 0 118 // 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!! 120 bool test() { 121 return std::is_heap(c.begin(), c.end(), Comp()); 122 } 123 #endif 124 125 protected: 126 IndexArray index_array; 127 Compare comp; 128 RandomAccessContainer c; 129 ID id; 130 }; 131 132 133 } 134 135 #endif // BOOST_MUTABLE_QUEUE_HPP 136