| 1 | /* $Id: avl_Destroy.cpp.h 28800 2010-04-27 08:22:32Z vboxsync $ */
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| 2 | /** @file
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| 3 | * kAVLDestroy - Walk the tree calling a callback to destroy all the nodes.
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| 4 | */
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| 5 |
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| 6 | /*
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| 7 | * Copyright (C) 1999-2007 knut st. osmundsen (bird-src-spam@anduin.net)
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| 8 | *
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| 9 | * This file is part of VirtualBox Open Source Edition (OSE), as
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| 10 | * available from http://www.virtualbox.org. This file is free software;
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| 11 | * you can redistribute it and/or modify it under the terms of the GNU
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| 12 | * General Public License (GPL) as published by the Free Software
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| 13 | * Foundation, in version 2 as it comes in the "COPYING" file of the
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| 14 | * VirtualBox OSE distribution. VirtualBox OSE is distributed in the
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| 15 | * hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
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| 16 | *
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| 17 | * The contents of this file may alternatively be used under the terms
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| 18 | * of the Common Development and Distribution License Version 1.0
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| 19 | * (CDDL) only, as it comes in the "COPYING.CDDL" file of the
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| 20 | * VirtualBox OSE distribution, in which case the provisions of the
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| 21 | * CDDL are applicable instead of those of the GPL.
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| 22 | *
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| 23 | * You may elect to license modified versions of this file under the
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| 24 | * terms and conditions of either the GPL or the CDDL or both.
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| 25 | */
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| 26 |
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| 27 | #ifndef _kAVLDestroy_h_
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| 28 | #define _kAVLDestroy_h_
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| 29 |
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| 30 |
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| 31 | /**
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| 32 | * Destroys the specified tree, starting with the root node and working our way down.
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| 33 | *
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| 34 | * @returns 0 on success.
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| 35 | * @returns Return value from callback on failure. On failure, the tree will be in
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| 36 | * an unbalanced condition and only further calls to the Destroy should be
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| 37 | * made on it. Note that the node we fail on will be considered dead and
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| 38 | * no action is taken to link it back into the tree.
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| 39 | * @param ppTree Pointer to the AVL-tree root node pointer.
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| 40 | * @param pfnCallBack Pointer to callback function.
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| 41 | * @param pvUser User parameter passed on to the callback function.
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| 42 | */
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| 43 | RTDECL(int) KAVL_FN(Destroy)(PPKAVLNODECORE ppTree, PKAVLCALLBACK pfnCallBack, void *pvUser)
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| 44 | {
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| 45 | unsigned cEntries;
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| 46 | PKAVLNODECORE apEntries[KAVL_MAX_STACK];
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| 47 | int rc;
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| 48 |
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| 49 | if (*ppTree == KAVL_NULL)
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| 50 | return 0;
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| 51 |
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| 52 | cEntries = 1;
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| 53 | apEntries[0] = KAVL_GET_POINTER(ppTree);
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| 54 | while (cEntries > 0)
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| 55 | {
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| 56 | /*
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| 57 | * Process the subtrees first.
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| 58 | */
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| 59 | PKAVLNODECORE pNode = apEntries[cEntries - 1];
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| 60 | if (pNode->pLeft != KAVL_NULL)
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| 61 | apEntries[cEntries++] = KAVL_GET_POINTER(&pNode->pLeft);
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| 62 | else if (pNode->pRight != KAVL_NULL)
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| 63 | apEntries[cEntries++] = KAVL_GET_POINTER(&pNode->pRight);
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| 64 | else
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| 65 | {
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| 66 | #ifdef KAVL_EQUAL_ALLOWED
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| 67 | /*
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| 68 | * Process nodes with the same key.
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| 69 | */
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| 70 | while (pNode->pList != KAVL_NULL)
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| 71 | {
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| 72 | PKAVLNODECORE pEqual = KAVL_GET_POINTER(&pNode->pList);
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| 73 | KAVL_SET_POINTER(&pNode->pList, KAVL_GET_POINTER_NULL(&pEqual->pList));
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| 74 | pEqual->pList = KAVL_NULL;
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| 75 |
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| 76 | rc = pfnCallBack(pEqual, pvUser);
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| 77 | if (rc)
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| 78 | return rc;
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| 79 | }
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| 80 | #endif
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| 81 |
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| 82 | /*
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| 83 | * Unlink the node.
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| 84 | */
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| 85 | if (--cEntries > 0)
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| 86 | {
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| 87 | PKAVLNODECORE pParent = apEntries[cEntries - 1];
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| 88 | if (KAVL_GET_POINTER(&pParent->pLeft) == pNode)
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| 89 | pParent->pLeft = KAVL_NULL;
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| 90 | else
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| 91 | pParent->pRight = KAVL_NULL;
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| 92 | }
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| 93 | else
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| 94 | *ppTree = KAVL_NULL;
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| 95 |
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| 96 | kASSERT(pNode->pLeft == KAVL_NULL);
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| 97 | kASSERT(pNode->pRight == KAVL_NULL);
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| 98 | rc = pfnCallBack(pNode, pvUser);
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| 99 | if (rc)
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| 100 | return rc;
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| 101 | }
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| 102 | } /* while */
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| 103 |
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| 104 | kASSERT(*ppTree == KAVL_NULL);
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| 105 |
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| 106 | return 0;
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| 107 | }
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| 108 |
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| 109 | #endif
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| 110 |
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