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