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git-svn-id: svn+ssh://svn.gna.org/svn/gnustep/libs/base/trunk@940 72102866-910b-0410-8b05-ffd578937521
101 lines
2.7 KiB
Objective-C
101 lines
2.7 KiB
Objective-C
/* Implementation for Objective-C SplayTree collection object
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Copyright (C) 1993, 1994, 1996 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/SplayTree.h>
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#include <objects/IndexedCollectionPrivate.h>
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@implementation SplayTree
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/* Make this a function ? */
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- (void) _doSplayOperationOnNode: aNode
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{
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id parent = [aNode parentNode];
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id parentRightChild =
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((parent == [self nilNode]) ? [self nilNode] : [parent rightNode]);
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if (aNode == _contents_root || aNode == [self nilNode])
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{
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return;
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}
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else if (aNode == parentRightChild)
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{
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if (parent == _contents_root)
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{
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[self leftRotateAroundNode:parent];
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}
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else if (NODE_IS_RIGHTCHILD(parent))
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{
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[self leftRotateAroundNode:[parent parentNode]];
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[self leftRotateAroundNode:parent];
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}
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else
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/* NODE_IS_LEFTCHILD(parent) */
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{
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[self leftRotateAroundNode:parent];
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[self rightRotateAroundNode:[aNode parentNode]];
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}
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}
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else
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/* aNode == parentLeftChild */
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{
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if (parent == _contents_root)
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{
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[self rightRotateAroundNode:parent];
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}
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else if (NODE_IS_LEFTCHILD(parent))
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{
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[self rightRotateAroundNode:[parent parentNode]];
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[self rightRotateAroundNode:parent];
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}
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else
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/* NODE_IS_RIGHTCHILD(parent) */
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{
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[self rightRotateAroundNode:parent];
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[self leftRotateAroundNode:[aNode parentNode]];
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}
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}
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}
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- (void) splayNode: aNode
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{
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while (aNode != _contents_root)
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[self _doSplayOperationOnNode:aNode];
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}
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/* We could make this a little more efficient by doing the splay as
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we search down the tree for the correct insertion point. */
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- (void) sortAddObject: newObject
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{
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[super sortAddObject: newObject];
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[self splayNode: newObject];
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}
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- (void) removeObject: anObject
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{
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id parent = [anObject parentNode];
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[super removeObject: anObject];
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if (parent && parent != [self nilNode])
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[self splayNode:parent];
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}
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@end
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