Chris@16: //
Chris@16: //=======================================================================
Chris@16: // Copyright 1997, 1998, 1999, 2000 University of Notre Dame.
Chris@16: // Authors: Andrew Lumsdaine, Lie-Quan Lee, Jeremy G. Siek
Chris@16: //
Chris@16: // Distributed under the Boost Software License, Version 1.0. (See
Chris@16: // accompanying file LICENSE_1_0.txt or copy at
Chris@16: // http://www.boost.org/LICENSE_1_0.txt)
Chris@16: //=======================================================================
Chris@16: //
Chris@16: #ifndef BOOST_MUTABLE_QUEUE_HPP
Chris@16: #define BOOST_MUTABLE_QUEUE_HPP
Chris@16: 
Chris@16: #include <vector>
Chris@16: #include <algorithm>
Chris@16: #include <functional>
Chris@16: #include <boost/property_map/property_map.hpp>
Chris@16: #include <boost/pending/mutable_heap.hpp>
Chris@16: #include <boost/pending/is_heap.hpp>
Chris@16: #include <boost/graph/detail/array_binary_tree.hpp>
Chris@16: #include <iterator>
Chris@16: 
Chris@16: namespace boost {
Chris@16: 
Chris@16:   // The mutable queue whose elements are indexed
Chris@16:   //
Chris@16:   // This adaptor provides a special kind of priority queue that has
Chris@16:   // and update operation. This allows the ordering of the items to
Chris@16:   // change. After the ordering criteria for item x changes, one must
Chris@16:   // call the Q.update(x)
Chris@16:   //
Chris@16:   // In order to efficiently find x in the queue, a functor must be
Chris@16:   // provided to map value_type to a unique ID, which the
Chris@16:   // mutable_queue will then use to map to the location of the
Chris@16:   // item. The ID's generated must be between 0 and N, where N is the
Chris@16:   // value passed to the constructor of mutable_queue
Chris@16: 
Chris@16:   template <class IndexedType,
Chris@16:             class RandomAccessContainer = std::vector<IndexedType>,
Chris@16:             class Comp = std::less<typename RandomAccessContainer::value_type>,
Chris@16:             class ID = identity_property_map >
Chris@16:   class mutable_queue {
Chris@16:   public:
Chris@16:     typedef IndexedType value_type;
Chris@16:     typedef typename RandomAccessContainer::size_type size_type;
Chris@16:   protected:
Chris@16:     typedef typename RandomAccessContainer::iterator iterator;
Chris@16: #if !defined BOOST_NO_STD_ITERATOR_TRAITS
Chris@16:     typedef array_binary_tree_node<iterator, ID> Node;
Chris@16: #else
Chris@16:     typedef array_binary_tree_node<iterator, value_type, ID> Node;
Chris@16: #endif
Chris@16:     typedef compare_array_node<RandomAccessContainer,Comp> Compare;
Chris@16:     typedef std::vector<size_type> IndexArray;
Chris@16:   public:
Chris@16:     typedef Compare value_compare;
Chris@16:     typedef ID id_generator;
Chris@16: 
Chris@16:     mutable_queue(size_type n, const Comp& x, const ID& _id)
Chris@16:       : index_array(n), comp(x), id(_id) {
Chris@16:       c.reserve(n);
Chris@16:     }
Chris@16:     template <class ForwardIterator>
Chris@16:     mutable_queue(ForwardIterator first, ForwardIterator last,
Chris@16:                   const Comp& x, const ID& _id)
Chris@16:       : index_array(std::distance(first, last)), comp(x), id(_id)
Chris@16:     {
Chris@16:       while( first != last ) {
Chris@16:         push(*first);
Chris@16:         ++first;
Chris@16:       }
Chris@16:     }
Chris@16: 
Chris@16:     bool empty() const { return c.empty(); }
Chris@16: 
Chris@16:     void pop() {
Chris@16:       value_type tmp = c.back();
Chris@16:       c.back() = c.front();
Chris@16:       c.front() = tmp;
Chris@16: 
Chris@16:       size_type id_f = get(id, c.back());
Chris@16:       size_type id_b = get(id, tmp);
Chris@16:       size_type i = index_array[ id_b ];
Chris@16:       index_array[ id_b ] = index_array[ id_f ];
Chris@16:       index_array[ id_f ] = i;
Chris@16: 
Chris@16:       c.pop_back();
Chris@16:       Node node(c.begin(), c.end(), c.begin(), id);
Chris@16:       down_heap(node, comp, index_array);
Chris@16:     }
Chris@16:     void push(const IndexedType& x) {
Chris@16:       c.push_back(x);
Chris@16:       /*set index-array*/
Chris@16:       index_array[ get(id, x) ] = c.size()-1;
Chris@16:       Node node(c.begin(), c.end(), c.end() - 1, id);
Chris@16:       up_heap(node, comp, index_array);
Chris@16:     }
Chris@16: 
Chris@16:     void update(const IndexedType& x) {
Chris@16:       size_type current_pos = index_array[ get(id, x) ];
Chris@16:       c[current_pos] = x;
Chris@16: 
Chris@16:       Node node(c.begin(), c.end(), c.begin()+current_pos, id);
Chris@16:       update_heap(node, comp, index_array);
Chris@16:     }
Chris@16: 
Chris@16:     value_type& front() { return c.front(); }
Chris@16:     value_type& top() { return c.front(); }
Chris@16: 
Chris@16:     const value_type& front() const { return c.front(); }
Chris@16:     const value_type& top() const { return c.front(); }
Chris@16: 
Chris@16:     size_type size() const { return c.size(); }
Chris@16: 
Chris@16:     void clear() { c.clear(); }
Chris@16: 
Chris@16: #if 0
Chris@16:         // dwa 2003/7/11 - I don't know what compiler is supposed to
Chris@16:         // be able to compile this, but is_heap is not standard!!
Chris@16:     bool test() {
Chris@16:       return std::is_heap(c.begin(), c.end(), Comp());
Chris@16:     }
Chris@16: #endif
Chris@16: 
Chris@16:    protected:
Chris@16:     IndexArray index_array;
Chris@16:     Compare comp;
Chris@16:     RandomAccessContainer c;
Chris@16:     ID id;
Chris@16:   };
Chris@16: 
Chris@16: 
Chris@16: }
Chris@16: 
Chris@16: #endif // BOOST_MUTABLE_QUEUE_HPP