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 26 // The mutable queue whose elements are indexed 27 // 28 // This adaptor provides a special kind of priority queue that has 29 // and update operation. This allows the ordering of the items to 30 // change. After the ordering criteria for item x changes, one must 31 // call the Q.update(x) 32 // 33 // In order to efficiently find x in the queue, a functor must be 34 // provided to map value_type to a unique ID, which the 35 // mutable_queue will then use to map to the location of the 36 // item. The ID's generated must be between 0 and N, where N is the 37 // value passed to the constructor of mutable_queue 38 39 template < class IndexedType, 40 class RandomAccessContainer = std::vector< IndexedType >, 41 class Comp = std::less< typename RandomAccessContainer::value_type >, 42 class ID = identity_property_map > 43 class mutable_queue 44 { 45 public: 46 typedef IndexedType value_type; 47 typedef typename RandomAccessContainer::size_type size_type; 48 49 protected: 50 typedef typename RandomAccessContainer::iterator iterator; 51 #if !defined BOOST_NO_STD_ITERATOR_TRAITS 52 typedef array_binary_tree_node< iterator, ID > Node; 53 #else 54 typedef array_binary_tree_node< iterator, value_type, ID > Node; 55 #endif 56 typedef compare_array_node< RandomAccessContainer, Comp > Compare; 57 typedef std::vector< size_type > IndexArray; 58 59 public: 60 typedef Compare value_compare; 61 typedef ID id_generator; 62 mutable_queue(size_type n,const Comp & x,const ID & _id)63 mutable_queue(size_type n, const Comp& x, const ID& _id) 64 : index_array(n), comp(x), id(_id) 65 { 66 c.reserve(n); 67 } 68 template < class ForwardIterator > mutable_queue(ForwardIterator first,ForwardIterator last,const Comp & x,const ID & _id)69 mutable_queue(ForwardIterator first, ForwardIterator last, const Comp& x, 70 const ID& _id) 71 : index_array(std::distance(first, last)), comp(x), id(_id) 72 { 73 while (first != last) 74 { 75 push(*first); 76 ++first; 77 } 78 } 79 empty() const80 bool empty() const { return c.empty(); } 81 pop()82 void pop() 83 { 84 value_type tmp = c.back(); 85 c.back() = c.front(); 86 c.front() = tmp; 87 88 size_type id_f = get(id, c.back()); 89 size_type id_b = get(id, tmp); 90 size_type i = index_array[id_b]; 91 index_array[id_b] = index_array[id_f]; 92 index_array[id_f] = i; 93 94 c.pop_back(); 95 Node node(c.begin(), c.end(), c.begin(), id); 96 down_heap(node, comp, index_array); 97 } push(const IndexedType & x)98 void push(const IndexedType& x) 99 { 100 c.push_back(x); 101 /*set index-array*/ 102 index_array[get(id, x)] = c.size() - 1; 103 Node node(c.begin(), c.end(), c.end() - 1, id); 104 up_heap(node, comp, index_array); 105 } 106 update(const IndexedType & x)107 void update(const IndexedType& x) 108 { 109 size_type current_pos = index_array[get(id, x)]; 110 c[current_pos] = x; 111 112 Node node(c.begin(), c.end(), c.begin() + current_pos, id); 113 update_heap(node, comp, index_array); 114 } 115 front()116 value_type& front() { return c.front(); } top()117 value_type& top() { return c.front(); } 118 front() const119 const value_type& front() const { return c.front(); } top() const120 const value_type& top() const { return c.front(); } 121 size() const122 size_type size() const { return c.size(); } 123 clear()124 void clear() { c.clear(); } 125 126 #if 0 127 // dwa 2003/7/11 - I don't know what compiler is supposed to 128 // be able to compile this, but is_heap is not standard!! 129 bool test() { 130 return std::is_heap(c.begin(), c.end(), Comp()); 131 } 132 #endif 133 134 protected: 135 IndexArray index_array; 136 Compare comp; 137 RandomAccessContainer c; 138 ID id; 139 }; 140 141 } 142 143 #endif // BOOST_MUTABLE_QUEUE_HPP 144