| 1 | /* $Id: kAvlDestroy.h 2 2007-11-16 16:07:14Z bird $ */
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| 2 | /** @file
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| 3 | * kAvlTmpl - Templated AVL Trees, Destroy the tree.
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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 kStuff.
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| 10 | *
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| 11 | * kStuff is free software; you can redistribute it and/or
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| 12 | * modify it under the terms of the GNU Lesser General Public
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| 13 | * License as published by the Free Software Foundation; either
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| 14 | * version 2.1 of the License, or (at your option) any later version.
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| 15 | *
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| 16 | * kStuff is distributed in the hope that it will be useful,
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| 17 | * but WITHOUT ANY WARRANTY; without even the implied warranty of
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| 18 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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| 19 | * Lesser General Public License for more details.
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| 20 | *
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| 21 | * You should have received a copy of the GNU Lesser General Public
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| 22 | * License along with kStuff; if not, write to the Free Software
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| 23 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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| 24 | *
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| 25 | *
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| 26 | * As a special exception, since this is a source file and not a header
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| 27 | * file, you are granted permission to #include this file as you wish
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| 28 | * without this in itself causing the resulting program or whatever to be
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| 29 | * covered by the LGPL license. This exception does not however invalidate
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| 30 | * any other reasons why the resulting program/whatever should not be
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| 31 | * covered the LGPL or GPL.
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| 32 | */
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| 33 |
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| 34 |
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| 35 | /**
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| 36 | * Destroys the specified tree, starting with the root node and working our way down.
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| 37 | *
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| 38 | * @returns 0 on success.
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| 39 | * @returns Return value from callback on failure. On failure, the tree will be in
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| 40 | * an unbalanced condition and only further calls to the Destroy should be
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| 41 | * made on it. Note that the node we fail on will be considered dead and
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| 42 | * no action is taken to link it back into the tree.
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| 43 | * @param ppTree Pointer to the AVL-tree root node pointer.
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| 44 | * @param pfnCallBack Pointer to callback function.
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| 45 | * @param pvUser User parameter passed on to the callback function.
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| 46 | */
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| 47 | KAVL_DECL(int) KAVL_FN(Destroy)(KAVLTREEPTR *ppTree, KAVL_TYPE(PFN,CALLBACK) pfnCallBack, void *pvUser)
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| 48 | {
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| 49 | unsigned cEntries;
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| 50 | KAVLNODE *apEntries[KAVL_MAX_STACK];
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| 51 | int rc;
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| 52 |
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| 53 | if (*ppTree == KAVL_NULL)
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| 54 | return 0;
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| 55 |
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| 56 | cEntries = 1;
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| 57 | apEntries[0] = KAVL_GET_POINTER(ppTree);
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| 58 | while (cEntries > 0)
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| 59 | {
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| 60 | /*
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| 61 | * Process the subtrees first.
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| 62 | */
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| 63 | KAVLNODE *pNode = apEntries[cEntries - 1];
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| 64 | if (pNode->mpLeft != KAVL_NULL)
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| 65 | apEntries[cEntries++] = KAVL_GET_POINTER(&pNode->mpLeft);
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| 66 | else if (pNode->mpRight != KAVL_NULL)
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| 67 | apEntries[cEntries++] = KAVL_GET_POINTER(&pNode->mpRight);
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| 68 | else
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| 69 | {
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| 70 | #ifdef KAVL_EQUAL_ALLOWED
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| 71 | /*
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| 72 | * Process nodes with the same key.
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| 73 | */
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| 74 | while (pNode->pList != KAVL_NULL)
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| 75 | {
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| 76 | KAVLNODE *pEqual = KAVL_GET_POINTER(&pNode->pList);
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| 77 | KAVL_SET_POINTER(&pNode->pList, KAVL_GET_POINTER_NULL(&pEqual->pList));
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| 78 | pEqual->pList = KAVL_NULL;
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| 79 |
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| 80 | rc = pfnCallBack(pEqual, pvUser);
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| 81 | if (rc)
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| 82 | return rc;
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| 83 | }
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| 84 | #endif
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| 85 |
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| 86 | /*
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| 87 | * Unlink the node.
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| 88 | */
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| 89 | if (--cEntries > 0)
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| 90 | {
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| 91 | KAVLNODE *pParent = apEntries[cEntries - 1];
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| 92 | if (KAVL_GET_POINTER(&pParent->mpLeft) == pNode)
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| 93 | pParent->mpLeft = KAVL_NULL;
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| 94 | else
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| 95 | pParent->mpRight = KAVL_NULL;
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| 96 | }
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| 97 | else
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| 98 | *ppTree = KAVL_NULL;
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| 99 |
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| 100 | kHlpAssert(pNode->mpLeft == KAVL_NULL);
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| 101 | kHlpAssert(pNode->mpRight == KAVL_NULL);
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| 102 | rc = pfnCallBack(pNode, pvUser);
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| 103 | if (rc)
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| 104 | return rc;
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| 105 | }
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| 106 | } /* while */
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| 107 | kHlpAssert(*ppTree == KAVL_NULL);
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| 108 |
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| 109 | return 0;
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| 110 | }
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| 111 |
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