avl_GetBestFit.cpp.h revision 677833bc953b6cb418c701facbdcf4aa18d6c44e
/* $Id$ */
/** @file
* kAVLGetBestFit - Get Best Fit routine for AVL trees.
* Intended specially on heaps. The tree should allow duplicate keys.
*
*/
/*
* Copyright (C) 1999-2002 knut st. osmundsen (bird-src-spam@anduin.net)
*
* This file is part of VirtualBox Open Source Edition (OSE), as
* available from http://www.virtualbox.org. This file is free software;
* you can redistribute it and/or modify it under the terms of the GNU
* General Public License as published by the Free Software Foundation,
* in version 2 as it comes in the "COPYING" file of the VirtualBox OSE
* distribution. VirtualBox OSE is distributed in the hope that it will
* be useful, but WITHOUT ANY WARRANTY of any kind.
*
* If you received this file as part of a commercial VirtualBox
* distribution, then only the terms of your commercial VirtualBox
* license agreement apply instead of the previous paragraph.
*/
#ifndef _kAVLGetBestFit_h_
#define _kAVLGetBestFit_h_
/**
* Finds the best fitting node in the tree for the given Key value.
* @returns Pointer to the best fitting node found.
* @param ppTree Pointer to Pointer to the tree root node.
* @param Key The Key of which is to be found a best fitting match for..
* @param fAbove TRUE: Returned node is have the closest key to Key from above.
* FALSE: Returned node is have the closest key to Key from below.
* @sketch The best fitting node is always located in the searchpath above you.
* >= (above): The node where you last turned left.
* <= (below): the node where you last turned right.
*/
PKAVLNODECORE KAVL_FN(GetBestFit)(PPKAVLNODECORE ppTree, KAVLKEY Key, bool fAbove)
{
register PKAVLNODECORE pNode = KAVL_GET_POINTER_NULL(ppTree);
if (pNode)
{
PKAVLNODECORE pNodeLast = NULL;
if (fAbove)
{ /* pNode->Key >= Key */
while (KAVL_NE(pNode->Key, Key))
{
if (KAVL_G(pNode->Key, Key))
{
if (pNode->pLeft != KAVL_NULL)
{
pNodeLast = pNode;
pNode = KAVL_GET_POINTER(&pNode->pLeft);
}
else
return pNode;
}
else
{
if (pNode->pRight != KAVL_NULL)
pNode = KAVL_GET_POINTER(&pNode->pRight);
else
return pNodeLast;
}
}
}
else
{ /* pNode->Key <= Key */
while (KAVL_NE(pNode->Key, Key))
{
if (KAVL_G(pNode->Key, Key))
{
if (pNode->pLeft != KAVL_NULL)
pNode = KAVL_GET_POINTER(&pNode->pLeft);
else
return pNodeLast;
}
else
{
if (pNode->pRight != KAVL_NULL)
{
pNodeLast = pNode;
pNode = KAVL_GET_POINTER(&pNode->pRight);
}
else
return pNode;
}
}
}
}
/* perfect match or nothing. */
return pNode;
}
#endif