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/* $Id: avl_GetBestFit.cpp.h $ */
/** @file
* kAVLGetBestFit - Get Best Fit routine for AVL trees.
* Intended specially on heaps. The tree should allow duplicate keys.
*
*/
/*
* Copyright (C) 2006-2023 Oracle and/or its affiliates.
*
* This file is part of VirtualBox base platform packages, as
* available from https://www.virtualbox.org.
*
* This program 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 3 of the
* License.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, see <https://www.gnu.org/licenses>.
*
* The contents of this file may alternatively be used under the terms
* of the Common Development and Distribution License Version 1.0
* (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
* in the VirtualBox distribution, in which case the provisions of the
* CDDL are applicable instead of those of the GPL.
*
* You may elect to license modified versions of this file under the
* terms and conditions of either the GPL or the CDDL or both.
*
* SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
*/
#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.
*/
KAVL_DECL(PKAVLNODECORE) KAVL_FN(GetBestFit)(PPKAVLNODECORE ppTree, KAVLKEY Key, bool fAbove)
{
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
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