| 1 | /* $Id: kAvlDestroy.h 29 2009-07-01 20:30:29Z 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) 1999-2009 Knut St. Osmundsen <bird-kStuff-spamix@anduin.net>
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| 8 | *
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| 9 | * Permission is hereby granted, free of charge, to any person
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| 10 | * obtaining a copy of this software and associated documentation
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| 11 | * files (the "Software"), to deal in the Software without
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| 12 | * restriction, including without limitation the rights to use,
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| 13 | * copy, modify, merge, publish, distribute, sublicense, and/or sell
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| 14 | * copies of the Software, and to permit persons to whom the
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| 15 | * Software is furnished to do so, subject to the following
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| 16 | * conditions:
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| 17 | *
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| 18 | * The above copyright notice and this permission notice shall be
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| 19 | * included in all copies or substantial portions of the Software.
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| 20 | *
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| 21 | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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| 22 | * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
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| 23 | * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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| 24 | * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
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| 25 | * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
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| 26 | * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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| 27 | * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
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| 28 | * OTHER DEALINGS IN THE SOFTWARE.
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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 pRoot Pointer to the AVL-tree root structure.
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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 | KAVL_DECL(int) KAVL_FN(Destroy)(KAVLROOT *pRoot, KAVL_TYPE(PFN,CALLBACK) pfnCallBack, void *pvUser)
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| 44 | {
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| 45 | #ifdef KAVL_LOOKTHRU
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| 46 | unsigned i;
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| 47 | #endif
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| 48 | unsigned cEntries;
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| 49 | KAVLNODE *apEntries[KAVL_MAX_STACK];
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| 50 | int rc;
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| 51 |
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| 52 | KAVL_WRITE_LOCK(pRoot);
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| 53 | if (pRoot->mpRoot == KAVL_NULL)
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| 54 | {
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| 55 | KAVL_WRITE_UNLOCK(pRoot);
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| 56 | return 0;
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| 57 | }
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| 58 |
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| 59 | #ifdef KAVL_LOOKTHRU
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| 60 | /*
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| 61 | * Kill the lookthru cache.
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| 62 | */
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| 63 | for (i = 0; i < (KAVL_LOOKTHRU); i++)
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| 64 | pRoot->maLookthru[i] = KAVL_NULL;
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| 65 | #endif
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| 66 |
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| 67 | cEntries = 1;
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| 68 | apEntries[0] = KAVL_GET_POINTER(&pRoot->mpRoot);
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| 69 | while (cEntries > 0)
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| 70 | {
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| 71 | /*
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| 72 | * Process the subtrees first.
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| 73 | */
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| 74 | KAVLNODE *pNode = apEntries[cEntries - 1];
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| 75 | if (pNode->mpLeft != KAVL_NULL)
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| 76 | apEntries[cEntries++] = KAVL_GET_POINTER(&pNode->mpLeft);
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| 77 | else if (pNode->mpRight != KAVL_NULL)
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| 78 | apEntries[cEntries++] = KAVL_GET_POINTER(&pNode->mpRight);
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| 79 | else
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| 80 | {
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| 81 | #ifdef KAVL_EQUAL_ALLOWED
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| 82 | /*
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| 83 | * Process nodes with the same key.
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| 84 | */
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| 85 | while (pNode->pList != KAVL_NULL)
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| 86 | {
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| 87 | KAVLNODE *pEqual = KAVL_GET_POINTER(&pNode->pList);
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| 88 | KAVL_SET_POINTER(&pNode->pList, KAVL_GET_POINTER_NULL(&pEqual->pList));
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| 89 | pEqual->pList = KAVL_NULL;
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| 90 |
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| 91 | rc = pfnCallBack(pEqual, pvUser);
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| 92 | if (rc)
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| 93 | {
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| 94 | KAVL_WRITE_UNLOCK(pRoot);
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| 95 | return rc;
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| 96 | }
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| 97 | }
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| 98 | #endif
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| 99 |
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| 100 | /*
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| 101 | * Unlink the node.
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| 102 | */
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| 103 | if (--cEntries > 0)
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| 104 | {
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| 105 | KAVLNODE *pParent = apEntries[cEntries - 1];
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| 106 | if (KAVL_GET_POINTER(&pParent->mpLeft) == pNode)
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| 107 | pParent->mpLeft = KAVL_NULL;
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| 108 | else
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| 109 | pParent->mpRight = KAVL_NULL;
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| 110 | }
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| 111 | else
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| 112 | pRoot->mpRoot = KAVL_NULL;
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| 113 |
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| 114 | kHlpAssert(pNode->mpLeft == KAVL_NULL);
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| 115 | kHlpAssert(pNode->mpRight == KAVL_NULL);
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| 116 | rc = pfnCallBack(pNode, pvUser);
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| 117 | if (rc)
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| 118 | {
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| 119 | KAVL_WRITE_UNLOCK(pRoot);
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| 120 | return rc;
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| 121 | }
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| 122 | }
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| 123 | } /* while */
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| 124 | kHlpAssert(pRoot->mpRoot == KAVL_NULL);
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| 125 |
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| 126 | KAVL_WRITE_UNLOCK(pRoot);
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| 127 | return 0;
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| 128 | }
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| 129 |
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