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/* $Id: kAvlGetBestFit.h 29 2009-07-01 20:30:29Z bird $ */
/** @file
* kAvlTmpl - Templated AVL Trees, Get Best Fitting Node.
*/
/*
* Copyright (c) 1999-2009 Knut St. Osmundsen <bird-kStuff-spamix@anduin.net>
*
* Permission is hereby granted, free of charge, to any person
* obtaining a copy of this software and associated documentation
* files (the "Software"), to deal in the Software without
* restriction, including without limitation the rights to use,
* copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following
* conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
* OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
* HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
* WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
* OTHER DEALINGS IN THE SOFTWARE.
*/
/**
* Finds the best fitting node in the tree for the given Key value.
*
* @returns Pointer to the best fitting node found.
* @param pRoot Pointer to the AVL-tree root structure.
* @param Key The Key of which is to be found a best fitting match for..
* @param fAbove K_TRUE: Returned node is have the closest key to Key from above.
* K_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(KAVLNODE *) KAVL_FN(GetBestFit)(KAVLROOT *pRoot, KAVLKEY Key, KBOOL fAbove)
{
register KAVLNODE *pNode;
KAVLNODE *pNodeLast;
KAVL_READ_LOCK(pLook);
if (pRoot->mpRoot == KAVL_NULL)
{
KAVL_READ_UNLOCK(pLook);
return NULL;
}
pNode = KAVL_GET_POINTER(&pRoot->mpRoot);
pNodeLast = NULL;
if (fAbove)
{ /* pNode->mKey >= Key */
while (KAVL_NE(pNode->mKey, Key))
{
if (KAVL_G(pNode->mKey, Key))
{
if (pNode->mpLeft == KAVL_NULL)
{
KAVL_READ_UNLOCK(pLook);
return pNode;
}
pNodeLast = pNode;
pNode = KAVL_GET_POINTER(&pNode->mpLeft);
}
else
{
if (pNode->mpRight == KAVL_NULL)
{
KAVL_READ_UNLOCK(pLook);
return pNodeLast;
}
pNode = KAVL_GET_POINTER(&pNode->mpRight);
}
}
}
else
{ /* pNode->mKey <= Key */
while (KAVL_NE(pNode->mKey, Key))
{
if (KAVL_G(pNode->mKey, Key))
{
if (pNode->mpLeft == KAVL_NULL)
{
KAVL_READ_UNLOCK(pLook);
return pNodeLast;
}
pNode = KAVL_GET_POINTER(&pNode->mpLeft);
}
else
{
if (pNode->mpRight == KAVL_NULL)
{
KAVL_READ_UNLOCK(pLook);
return pNode;
}
pNodeLast = pNode;
pNode = KAVL_GET_POINTER(&pNode->mpRight);
}
}
}
/* perfect match or nothing. */
KAVL_READ_UNLOCK(pLook);
return pNode;
}
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