williamr@2: //
williamr@2: //=======================================================================
williamr@2: // Copyright 1997, 1998, 1999, 2000 University of Notre Dame.
williamr@2: // Authors: Andrew Lumsdaine, Lie-Quan Lee, Jeremy G. Siek
williamr@2: //
williamr@2: // Distributed under the Boost Software License, Version 1.0. (See
williamr@2: // accompanying file LICENSE_1_0.txt or copy at
williamr@2: // http://www.boost.org/LICENSE_1_0.txt)
williamr@2: //=======================================================================
williamr@2: //
williamr@2: #ifndef BOOST_GRAPH_DETAIL_MUTABLE_HEAP_H
williamr@2: #define BOOST_GRAPH_DETAIL_MUTABLE_HEAP_H
williamr@2: 
williamr@2: /*
williamr@2:   There are a few things wrong with this set of functions.
williamr@2: 
williamr@2:   ExternalData should be removed, it is not part of the core
williamr@2:   algorithm. It can be handled inside the tree nodes.
williamr@2: 
williamr@2:   The swap() should be replaced by assignment since its use is causing
williamr@2:   the number of memory references to double.
williamr@2: 
williamr@2:   The min_element should be replaced by a fixed length loop
williamr@2:   (fixed at d for d-heaps).
williamr@2: 
williamr@2:   The member functions of TreeNode should be changed to global
williamr@2:   functions.
williamr@2: 
williamr@2:   These functions will be replaced by those in heap_tree.h
williamr@2: 
williamr@2:  */
williamr@2: 
williamr@2: namespace boost {
williamr@2: 
williamr@2:   template <class TreeNode, class Compare, class ExternalData>
williamr@2:   inline TreeNode up_heap(TreeNode x, const Compare& comp, ExternalData& edata) {
williamr@2:     while (x.has_parent() && comp(x, x.parent()))
williamr@2:       x.swap(x.parent(), edata);
williamr@2:     return x;
williamr@2:   }
williamr@2: 
williamr@2:   template <class TreeNode, class Compare, class ExternalData>
williamr@2:   inline TreeNode down_heap(TreeNode x, const Compare& comp, ExternalData& edata) {
williamr@2:     while (x.children().size() > 0) {
williamr@2:       typename TreeNode::children_type::iterator 
williamr@2:         child_iter = std::min_element(x.children().begin(),
williamr@2:                                       x.children().end(), 
williamr@2:                                       comp);
williamr@2:       if (comp(*child_iter, x))
williamr@2:         x.swap(*child_iter, edata);
williamr@2:       else
williamr@2:         break;
williamr@2:     }
williamr@2:     return x;
williamr@2:   }
williamr@2: 
williamr@2:   template <class TreeNode, class Compare, class ExternalData>
williamr@2:   inline void update_heap(TreeNode x, const Compare& comp, ExternalData& edata) {
williamr@2:     x = down_heap(x, comp, edata);
williamr@2:     (void)up_heap(x, comp, edata);
williamr@2:   }
williamr@2: 
williamr@2: }
williamr@2: #endif