| 1 | /* $Id: avl_GetBestFit.cpp.h 402 2007-01-28 08:44:20Z vboxsync $ */
|
|---|
| 2 | /** @file
|
|---|
| 3 | * kAVLGetBestFit - Get Best Fit routine for AVL trees.
|
|---|
| 4 | * Intended specially on heaps. The tree should allow duplicate keys.
|
|---|
| 5 | *
|
|---|
| 6 | */
|
|---|
| 7 |
|
|---|
| 8 | /*
|
|---|
| 9 | * Copyright (C) 1999-2002 knut st. osmundsen ([email protected])
|
|---|
| 10 | *
|
|---|
| 11 | * This file is part of VirtualBox Open Source Edition (OSE), as
|
|---|
| 12 | * available from http://www.virtualbox.org. This file is free software;
|
|---|
| 13 | * you can redistribute it and/or modify it under the terms of the GNU
|
|---|
| 14 | * General Public License as published by the Free Software Foundation,
|
|---|
| 15 | * in version 2 as it comes in the "COPYING" file of the VirtualBox OSE
|
|---|
| 16 | * distribution. VirtualBox OSE is distributed in the hope that it will
|
|---|
| 17 | * be useful, but WITHOUT ANY WARRANTY of any kind.
|
|---|
| 18 | *
|
|---|
| 19 | * If you received this file as part of a commercial VirtualBox
|
|---|
| 20 | * distribution, then only the terms of your commercial VirtualBox
|
|---|
| 21 | * license agreement apply instead of the previous paragraph.
|
|---|
| 22 | */
|
|---|
| 23 |
|
|---|
| 24 | #ifndef _kAVLGetBestFit_h_
|
|---|
| 25 | #define _kAVLGetBestFit_h_
|
|---|
| 26 |
|
|---|
| 27 |
|
|---|
| 28 | /**
|
|---|
| 29 | * Finds the best fitting node in the tree for the given Key value.
|
|---|
| 30 | * @returns Pointer to the best fitting node found.
|
|---|
| 31 | * @param ppTree Pointer to Pointer to the tree root node.
|
|---|
| 32 | * @param Key The Key of which is to be found a best fitting match for..
|
|---|
| 33 | * @param fAbove TRUE: Returned node is have the closest key to Key from above.
|
|---|
| 34 | * FALSE: Returned node is have the closest key to Key from below.
|
|---|
| 35 | * @sketch The best fitting node is always located in the searchpath above you.
|
|---|
| 36 | * >= (above): The node where you last turned left.
|
|---|
| 37 | * <= (below): the node where you last turned right.
|
|---|
| 38 | */
|
|---|
| 39 | RTDECL(PKAVLNODECORE) KAVL_FN(GetBestFit)(PPKAVLNODECORE ppTree, KAVLKEY Key, bool fAbove)
|
|---|
| 40 | {
|
|---|
| 41 | register PKAVLNODECORE pNode = KAVL_GET_POINTER_NULL(ppTree);
|
|---|
| 42 | if (pNode)
|
|---|
| 43 | {
|
|---|
| 44 | PKAVLNODECORE pNodeLast = NULL;
|
|---|
| 45 | if (fAbove)
|
|---|
| 46 | { /* pNode->Key >= Key */
|
|---|
| 47 | while (KAVL_NE(pNode->Key, Key))
|
|---|
| 48 | {
|
|---|
| 49 | if (KAVL_G(pNode->Key, Key))
|
|---|
| 50 | {
|
|---|
| 51 | if (pNode->pLeft != KAVL_NULL)
|
|---|
| 52 | {
|
|---|
| 53 | pNodeLast = pNode;
|
|---|
| 54 | pNode = KAVL_GET_POINTER(&pNode->pLeft);
|
|---|
| 55 | }
|
|---|
| 56 | else
|
|---|
| 57 | return pNode;
|
|---|
| 58 | }
|
|---|
| 59 | else
|
|---|
| 60 | {
|
|---|
| 61 | if (pNode->pRight != KAVL_NULL)
|
|---|
| 62 | pNode = KAVL_GET_POINTER(&pNode->pRight);
|
|---|
| 63 | else
|
|---|
| 64 | return pNodeLast;
|
|---|
| 65 | }
|
|---|
| 66 | }
|
|---|
| 67 | }
|
|---|
| 68 | else
|
|---|
| 69 | { /* pNode->Key <= Key */
|
|---|
| 70 | while (KAVL_NE(pNode->Key, Key))
|
|---|
| 71 | {
|
|---|
| 72 | if (KAVL_G(pNode->Key, Key))
|
|---|
| 73 | {
|
|---|
| 74 | if (pNode->pLeft != KAVL_NULL)
|
|---|
| 75 | pNode = KAVL_GET_POINTER(&pNode->pLeft);
|
|---|
| 76 | else
|
|---|
| 77 | return pNodeLast;
|
|---|
| 78 | }
|
|---|
| 79 | else
|
|---|
| 80 | {
|
|---|
| 81 | if (pNode->pRight != KAVL_NULL)
|
|---|
| 82 | {
|
|---|
| 83 | pNodeLast = pNode;
|
|---|
| 84 | pNode = KAVL_GET_POINTER(&pNode->pRight);
|
|---|
| 85 | }
|
|---|
| 86 | else
|
|---|
| 87 | return pNode;
|
|---|
| 88 | }
|
|---|
| 89 | }
|
|---|
| 90 | }
|
|---|
| 91 | }
|
|---|
| 92 |
|
|---|
| 93 | /* perfect match or nothing. */
|
|---|
| 94 | return pNode;
|
|---|
| 95 | }
|
|---|
| 96 |
|
|---|
| 97 |
|
|---|
| 98 | #endif
|
|---|
