| 1 | /* $Id: kAvlGetBestFit.h 29 2009-07-01 20:30:29Z bird $ */
|
|---|
| 2 | /** @file
|
|---|
| 3 | * kAvlTmpl - Templated AVL Trees, Get Best Fitting Node.
|
|---|
| 4 | */
|
|---|
| 5 |
|
|---|
| 6 | /*
|
|---|
| 7 | * Copyright (c) 1999-2009 Knut St. Osmundsen <bird-kStuff-spamix@anduin.net>
|
|---|
| 8 | *
|
|---|
| 9 | * Permission is hereby granted, free of charge, to any person
|
|---|
| 10 | * obtaining a copy of this software and associated documentation
|
|---|
| 11 | * files (the "Software"), to deal in the Software without
|
|---|
| 12 | * restriction, including without limitation the rights to use,
|
|---|
| 13 | * copy, modify, merge, publish, distribute, sublicense, and/or sell
|
|---|
| 14 | * copies of the Software, and to permit persons to whom the
|
|---|
| 15 | * Software is furnished to do so, subject to the following
|
|---|
| 16 | * conditions:
|
|---|
| 17 | *
|
|---|
| 18 | * The above copyright notice and this permission notice shall be
|
|---|
| 19 | * included in all copies or substantial portions of the Software.
|
|---|
| 20 | *
|
|---|
| 21 | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
|
|---|
| 22 | * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
|
|---|
| 23 | * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
|
|---|
| 24 | * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
|
|---|
| 25 | * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
|
|---|
| 26 | * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
|
|---|
| 27 | * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
|
|---|
| 28 | * OTHER DEALINGS IN THE SOFTWARE.
|
|---|
| 29 | */
|
|---|
| 30 |
|
|---|
| 31 | /**
|
|---|
| 32 | * Finds the best fitting node in the tree for the given Key value.
|
|---|
| 33 | *
|
|---|
| 34 | * @returns Pointer to the best fitting node found.
|
|---|
| 35 | * @param pRoot Pointer to the AVL-tree root structure.
|
|---|
| 36 | * @param Key The Key of which is to be found a best fitting match for..
|
|---|
| 37 | * @param fAbove K_TRUE: Returned node is have the closest key to Key from above.
|
|---|
| 38 | * K_FALSE: Returned node is have the closest key to Key from below.
|
|---|
| 39 | * @sketch The best fitting node is always located in the searchpath above you.
|
|---|
| 40 | * >= (above): The node where you last turned left.
|
|---|
| 41 | * <= (below): the node where you last turned right.
|
|---|
| 42 | */
|
|---|
| 43 | KAVL_DECL(KAVLNODE *) KAVL_FN(GetBestFit)(KAVLROOT *pRoot, KAVLKEY Key, KBOOL fAbove)
|
|---|
| 44 | {
|
|---|
| 45 | register KAVLNODE *pNode;
|
|---|
| 46 | KAVLNODE *pNodeLast;
|
|---|
| 47 |
|
|---|
| 48 | KAVL_READ_LOCK(pLook);
|
|---|
| 49 | if (pRoot->mpRoot == KAVL_NULL)
|
|---|
| 50 | {
|
|---|
| 51 | KAVL_READ_UNLOCK(pLook);
|
|---|
| 52 | return NULL;
|
|---|
| 53 | }
|
|---|
| 54 |
|
|---|
| 55 | pNode = KAVL_GET_POINTER(&pRoot->mpRoot);
|
|---|
| 56 | pNodeLast = NULL;
|
|---|
| 57 | if (fAbove)
|
|---|
| 58 | { /* pNode->mKey >= Key */
|
|---|
| 59 | while (KAVL_NE(pNode->mKey, Key))
|
|---|
| 60 | {
|
|---|
| 61 | if (KAVL_G(pNode->mKey, Key))
|
|---|
| 62 | {
|
|---|
| 63 | if (pNode->mpLeft == KAVL_NULL)
|
|---|
| 64 | {
|
|---|
| 65 | KAVL_READ_UNLOCK(pLook);
|
|---|
| 66 | return pNode;
|
|---|
| 67 | }
|
|---|
| 68 | pNodeLast = pNode;
|
|---|
| 69 | pNode = KAVL_GET_POINTER(&pNode->mpLeft);
|
|---|
| 70 | }
|
|---|
| 71 | else
|
|---|
| 72 | {
|
|---|
| 73 | if (pNode->mpRight == KAVL_NULL)
|
|---|
| 74 | {
|
|---|
| 75 | KAVL_READ_UNLOCK(pLook);
|
|---|
| 76 | return pNodeLast;
|
|---|
| 77 | }
|
|---|
| 78 | pNode = KAVL_GET_POINTER(&pNode->mpRight);
|
|---|
| 79 | }
|
|---|
| 80 | }
|
|---|
| 81 | }
|
|---|
| 82 | else
|
|---|
| 83 | { /* pNode->mKey <= Key */
|
|---|
| 84 | while (KAVL_NE(pNode->mKey, Key))
|
|---|
| 85 | {
|
|---|
| 86 | if (KAVL_G(pNode->mKey, Key))
|
|---|
| 87 | {
|
|---|
| 88 | if (pNode->mpLeft == KAVL_NULL)
|
|---|
| 89 | {
|
|---|
| 90 | KAVL_READ_UNLOCK(pLook);
|
|---|
| 91 | return pNodeLast;
|
|---|
| 92 | }
|
|---|
| 93 | pNode = KAVL_GET_POINTER(&pNode->mpLeft);
|
|---|
| 94 | }
|
|---|
| 95 | else
|
|---|
| 96 | {
|
|---|
| 97 | if (pNode->mpRight == KAVL_NULL)
|
|---|
| 98 | {
|
|---|
| 99 | KAVL_READ_UNLOCK(pLook);
|
|---|
| 100 | return pNode;
|
|---|
| 101 | }
|
|---|
| 102 | pNodeLast = pNode;
|
|---|
| 103 | pNode = KAVL_GET_POINTER(&pNode->mpRight);
|
|---|
| 104 | }
|
|---|
| 105 | }
|
|---|
| 106 | }
|
|---|
| 107 |
|
|---|
| 108 | /* perfect match or nothing. */
|
|---|
| 109 | KAVL_READ_UNLOCK(pLook);
|
|---|
| 110 | return pNode;
|
|---|
| 111 | }
|
|---|
| 112 |
|
|---|
