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99 lines
2.5 KiB
Mathematica
99 lines
2.5 KiB
Mathematica
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/* Implementation for Objective-C Heap object
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Copyright (C) 1993,1994 Free Software Foundation, Inc.
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Written by: R. Andrew McCallum <mccallum@gnu.ai.mit.edu>
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Date: May 1993
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This file is part of the GNU Objective C Class Library.
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This library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Library General Public
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License as published by the Free Software Foundation; either
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version 2 of the License, or (at your option) any later version.
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This library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Library General Public License for more details.
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You should have received a copy of the GNU Library General Public
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License along with this library; if not, write to the Free
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Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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#include <objects/Heap.h>
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#include <objects/ArrayPrivate.h>
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#define HEAP_PARENT(i) (i/2)
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#define HEAP_LEFT(i) (2 * i)
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#define HEAP_RIGHT(i) ((2 * i) + 1)
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@implementation Heap
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/* We could take out the recursive call to make it a little more efficient */
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- heapifyFromIndex: (unsigned)index
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{
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unsigned right, left, largest;
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elt tmp;
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right = HEAP_RIGHT(index);
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left = HEAP_LEFT(index);
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if (left <= _count
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&& COMPARE_ELEMENTS(_contents_array[left],_contents_array[index]) > 0)
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largest = left;
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else
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largest = index;
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if (right <= _count
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&& COMPARE_ELEMENTS(_contents_array[right],_contents_array[largest]) > 0)
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largest = right;
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if (largest != index)
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{
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tmp = _contents_array[index];
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_contents_array[index] = _contents_array[largest];
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_contents_array[largest] = tmp;
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[self heapifyFromIndex:largest];
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}
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return self;
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}
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- heapify
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{
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int i;
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// could use objc_msg_lookup here;
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for (i = _count / 2; i >= 1; i--)
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[self heapifyFromIndex:i];
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return self;
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}
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- (elt) removeFirstElement
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{
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elt ret;
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if (_count == 0)
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NO_ELEMENT_FOUND_ERROR();
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ret = _contents_array[0];
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_contents_array[0] = _contents_array[_count-1];
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decrementCount(self);
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[self heapifyFromIndex:0];
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return ret;
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}
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- addElement: (elt)newElement
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{
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int i;
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incrementCount(self);
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for (i = _count-1;
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i > 0
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&& COMPARE_ELEMENTS(_contents_array[HEAP_PARENT(i)], newElement) < 0;
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i = HEAP_PARENT(i))
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{
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_contents_array[i] = _contents_array[HEAP_PARENT(i)];
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}
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_contents_array[i] = newElement;
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return self;
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}
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@end
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