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Diffstat (limited to 'src/lib/kStuff/include/k/kRbTmpl/kRbRemove2.h')
| -rw-r--r-- | src/lib/kStuff/include/k/kRbTmpl/kRbRemove2.h | 133 |
1 files changed, 133 insertions, 0 deletions
diff --git a/src/lib/kStuff/include/k/kRbTmpl/kRbRemove2.h b/src/lib/kStuff/include/k/kRbTmpl/kRbRemove2.h new file mode 100644 index 0000000..deed81d --- /dev/null +++ b/src/lib/kStuff/include/k/kRbTmpl/kRbRemove2.h @@ -0,0 +1,133 @@ +/* $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 +} + |