diff options
Diffstat (limited to 'src/VBox/Runtime/common/table/avl_RemoveNode.cpp.h')
| -rw-r--r-- | src/VBox/Runtime/common/table/avl_RemoveNode.cpp.h | 153 |
1 files changed, 153 insertions, 0 deletions
diff --git a/src/VBox/Runtime/common/table/avl_RemoveNode.cpp.h b/src/VBox/Runtime/common/table/avl_RemoveNode.cpp.h new file mode 100644 index 00000000..16e851cf --- /dev/null +++ b/src/VBox/Runtime/common/table/avl_RemoveNode.cpp.h @@ -0,0 +1,153 @@ +/* $Id: avl_RemoveNode.cpp.h $ */ +/** @file + * kAVLRemove2 - Remove specific node (by pointer) from an AVL tree. + */ + +/* + * 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 + */ + + +/** + * Removes the specified node from the tree. + * + * @returns Pointer to the removed node (NULL if not in the tree) + * @param ppTree Pointer to the AVL-tree root structure. + * @param pNode Pointer to the node to be removed. + * + * @remark This implementation isn't the most efficient, but it's relatively + * short and easier to manage. + */ +KAVL_DECL(PKAVLNODECORE) KAVL_FN(RemoveNode)(PPKAVLNODECORE ppTree, PKAVLNODECORE pNode) +{ +#ifdef KAVL_EQUAL_ALLOWED + /* + * Find the right node by key together with the parent node. + */ + KAVLKEY const Key = pNode->Key; + PKAVLNODECORE pParent = NULL; + PKAVLNODECORE pCurNode = KAVL_GET_POINTER_NULL(ppTree); + if (!pCurNode) + return NULL; + while (KAVL_NE(pCurNode->Key, Key)) + { + pParent = pCurNode; + if (KAVL_G(pCurNode->Key, Key)) + { + if (pCurNode->pLeft != KAVL_NULL) + pCurNode = KAVL_GET_POINTER(&pCurNode->pLeft); + else + return NULL; + } + else + { + if (pCurNode->pRight != KAVL_NULL) + pCurNode = KAVL_GET_POINTER(&pCurNode->pRight); + else + return NULL; + } + } + + if (pCurNode != pNode) + { + /* + * It's not the one we want, but it could be in the duplicate list. + */ + while (pCurNode->pList != KAVL_NULL) + { + PKAVLNODECORE pNext = KAVL_GET_POINTER(&pCurNode->pList); + if (pNext == pNode) + { + if (pNode->pList != KAVL_NULL) + KAVL_SET_POINTER(&pCurNode->pList, KAVL_GET_POINTER(&pNode->pList)); + else + pCurNode->pList = KAVL_NULL; + pNode->pList = KAVL_NULL; + return pNode; + } + pCurNode = pNext; + } + 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->pList == KAVL_NULL) + KAVL_FN(Remove)(ppTree, pNode->Key); + else + { + PKAVLNODECORE pNewUs = KAVL_GET_POINTER(&pNode->pList); + + pNewUs->uchHeight = pNode->uchHeight; + + if (pNode->pLeft != KAVL_NULL) + KAVL_SET_POINTER(&pNewUs->pLeft, KAVL_GET_POINTER(&pNode->pLeft)); + else + pNewUs->pLeft = KAVL_NULL; + + if (pNode->pRight != KAVL_NULL) + KAVL_SET_POINTER(&pNewUs->pRight, KAVL_GET_POINTER(&pNode->pRight)); + else + pNewUs->pRight = KAVL_NULL; + + if (pParent) + { + if (KAVL_GET_POINTER_NULL(&pParent->pLeft) == pNode) + KAVL_SET_POINTER(&pParent->pLeft, pNewUs); + else + KAVL_SET_POINTER(&pParent->pRight, pNewUs); + } + else + KAVL_SET_POINTER(ppTree, pNewUs); + } + + 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. + */ + KAVLNODE *pRemovedNode = KAVL_FN(Remove)(pRoot, pNode->Key); + if (pRemovedNode == pNode) + return pRemovedNode; + + KAVL_FN(Insert)(pRoot, pRemovedNode); + return NULL; +#endif +} + |