ubuntu/vbox/vboxguest/common/table/avl_Destroy.cpp.h

   1 /* $Id: avl_Destroy.cpp.h $ */
   2 /** @file
   3  * kAVLDestroy - Walk the tree calling a callback to destroy all the nodes.
   4  */
   5
   6 /*
   7  * Copyright (C) 2006-2017 Oracle Corporation
   8  *
   9  * This file is part of VirtualBox Open Source Edition (OSE), as
  10  * available from http://www.virtualbox.org. This file is free software;
  11  * you can redistribute it and/or modify it under the terms of the GNU
  12  * General Public License (GPL) as published by the Free Software
  13  * Foundation, in version 2 as it comes in the "COPYING" file of the
  14  * VirtualBox OSE distribution. VirtualBox OSE is distributed in the
  15  * hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
  16  *
  17  * The contents of this file may alternatively be used under the terms
  18  * of the Common Development and Distribution License Version 1.0
  19  * (CDDL) only, as it comes in the "COPYING.CDDL" file of the
  20  * VirtualBox OSE distribution, in which case the provisions of the
  21  * CDDL are applicable instead of those of the GPL.
  22  *
  23  * You may elect to license modified versions of this file under the
  24  * terms and conditions of either the GPL or the CDDL or both.
  25  */
  26
  27 #ifndef _kAVLDestroy_h_
  28 #define _kAVLDestroy_h_
  29
  30
  31 /**
  32  * Destroys the specified tree, starting with the root node and working our way down.
  33  *
  34  * @returns 0 on success.
  35  * @returns Return value from callback on failure. On failure, the tree will be in
  36  *          an unbalanced condition and only further calls to the Destroy should be
  37  *          made on it. Note that the node we fail on will be considered dead and
  38  *          no action is taken to link it back into the tree.
  39  * @param   ppTree          Pointer to the AVL-tree root node pointer.
  40  * @param   pfnCallBack     Pointer to callback function.
  41  * @param   pvUser          User parameter passed on to the callback function.
  42  */
  43 KAVL_DECL(int) KAVL_FN(Destroy)(PPKAVLNODECORE ppTree, PKAVLCALLBACK pfnCallBack, void *pvUser)
  44 {
  45     unsigned        cEntries;
  46     PKAVLNODECORE   apEntries[KAVL_MAX_STACK];
  47     int             rc;
  48
  49     if (*ppTree == KAVL_NULL)
  50         return VINF_SUCCESS;
  51
  52     cEntries = 1;
  53     apEntries[0] = KAVL_GET_POINTER(ppTree);
  54     while (cEntries > 0)
  55     {
  56         /*
  57          * Process the subtrees first.
  58          */
  59         PKAVLNODECORE pNode = apEntries[cEntries - 1];
  60         if (pNode->pLeft != KAVL_NULL)
  61             apEntries[cEntries++] = KAVL_GET_POINTER(&pNode->pLeft);
  62         else if (pNode->pRight != KAVL_NULL)
  63             apEntries[cEntries++] = KAVL_GET_POINTER(&pNode->pRight);
  64         else
  65         {
  66 #ifdef KAVL_EQUAL_ALLOWED
  67             /*
  68              * Process nodes with the same key.
  69              */
  70             while (pNode->pList != KAVL_NULL)
  71             {
  72                 PKAVLNODECORE pEqual = KAVL_GET_POINTER(&pNode->pList);
  73                 KAVL_SET_POINTER(&pNode->pList, KAVL_GET_POINTER_NULL(&pEqual->pList));
  74                 pEqual->pList = KAVL_NULL;
  75
  76                 rc = pfnCallBack(pEqual, pvUser);
  77                 if (rc != VINF_SUCCESS)
  78                     return rc;
  79             }
  80 #endif
  81
  82             /*
  83              * Unlink the node.
  84              */
  85             if (--cEntries > 0)
  86             {
  87                 PKAVLNODECORE pParent = apEntries[cEntries - 1];
  88                 if (KAVL_GET_POINTER(&pParent->pLeft) == pNode)
  89                     pParent->pLeft = KAVL_NULL;
  90                 else
  91                     pParent->pRight = KAVL_NULL;
  92             }
  93             else
  94                 *ppTree = KAVL_NULL;
  95
  96             kASSERT(pNode->pLeft == KAVL_NULL);
  97             kASSERT(pNode->pRight == KAVL_NULL);
  98             rc = pfnCallBack(pNode, pvUser);
  99             if (rc != VINF_SUCCESS)
 100                 return rc;
 101         }
 102     } /* while */
 103
 104     kASSERT(*ppTree == KAVL_NULL);
 105
 106     return VINF_SUCCESS;
 107 }
 108
 109 #endif
 110