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/* $Id: kRbRemove2.h 35 2009-11-08 19:39:03Z bird $ */
/** @file
* kRbTmpl - Templated Red-Black Trees, Remove A Specific 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.
*/
/**
* Removes the specified node from the tree.
*
* @returns Pointer to the removed node (NULL if not in the tree)
* @param pRoot Pointer to the Red-Back tree's root structure.
* @param Key The Key of which is to be found a best fitting match for..
*
* @remark This implementation isn't the most efficient, but this short and
* easier to manage.
*/
KRB_DECL(KRBNODE *) KRB_FN(Remove2)(KRBROOT *pRoot, KRBNODE *pNode)
{
#ifdef KRB_EQUAL_ALLOWED
/*
* Find the right node by key and see if it's what we want.
*/
KRBNODE *pParent;
KRBNODE *pCurNode = KRB_FN(GetWithParent)(pRoot, pNode->mKey, &pParent);
if (!pCurNode)
return NULL;
KRB_WRITE_LOCK(pRoot); /** @todo the locking here isn't 100% sane. The only way to archive that is by no calling worker functions. */
if (pCurNode != pNode)
{
/*
* It's not the one we want, but it could be in the duplicate list.
*/
while (pCurNode->mpList != KRB_NULL)
{
KRBNODE *pNext = KRB_GET_POINTER(&pCurNode->mpList);
if (pNext == pNode)
{
KRB_SET_POINTER_NULL(&pCurNode->mpList, KRB_GET_POINTER_NULL(&pNode->mpList));
pNode->mpList = KRB_NULL;
KRB_CACHE_INVALIDATE_NODE(pRoot, pNode, pNode->mKey);
KRB_WRITE_UNLOCK(pRoot);
return pNode;
}
pCurNode = pNext;
}
KRB_WRITE_UNLOCK(pRoot);
return NULL;
}
/*
* Ok, it's the one we want alright.
*
* Simply remove it if it's the only one with they Key,
* if there are duplicates we'll have to unlink it and
* insert the first duplicate in our place.
*/
if (pNode->mpList == KRB_NULL)
{
KRB_WRITE_UNLOCK(pRoot);
KRB_FN(Remove)(pRoot, pNode->mKey);
}
else
{
KRBNODE *pNewUs = KRB_GET_POINTER(&pNode->mpList);
pNewUs->mHeight = pNode->mHeight;
if (pNode->mpLeft != KRB_NULL)
KRB_SET_POINTER(&pNewUs->mpLeft, KRB_GET_POINTER(&pNode->mpLeft))
else
pNewUs->mpLeft = KRB_NULL;
if (pNode->mpRight != KRB_NULL)
KRB_SET_POINTER(&pNewUs->mpRight, KRB_GET_POINTER(&pNode->mpRight))
else
pNewUs->mpRight = KRB_NULL;
if (pParent)
{
if (KRB_GET_POINTER_NULL(&pParent->mpLeft) == pNode)
KRB_SET_POINTER(&pParent->mpLeft, pNewUs);
else
KRB_SET_POINTER(&pParent->mpRight, pNewUs);
}
else
KRB_SET_POINTER(&pRoot->mpRoot, pNewUs);
KRB_CACHE_INVALIDATE_NODE(pRoot, pNode, pNode->mKey);
KRB_WRITE_UNLOCK(pRoot);
}
return pNode;
#else
/*
* Delete it, if we got the wrong one, reinsert it.
*
* This ASSUMS that the caller is NOT going to hand us a lot
* of wrong nodes but just uses this API for his convenience.
*/
KRBNODE *pRemovedNode = KRB_FN(Remove)(pRoot, pNode->mKey);
if (pRemovedNode == pNode)
return pRemovedNode;
KRB_FN(Insert)(pRoot, pRemovedNode);
return NULL;
#endif
}
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