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Diffstat (limited to 'src/lib/kStuff/include/k/kAvlTmpl/kAvlEnum.h')
| -rw-r--r-- | src/lib/kStuff/include/k/kAvlTmpl/kAvlEnum.h | 187 |
1 files changed, 187 insertions, 0 deletions
diff --git a/src/lib/kStuff/include/k/kAvlTmpl/kAvlEnum.h b/src/lib/kStuff/include/k/kAvlTmpl/kAvlEnum.h new file mode 100644 index 0000000..da151d1 --- /dev/null +++ b/src/lib/kStuff/include/k/kAvlTmpl/kAvlEnum.h @@ -0,0 +1,187 @@ +/* $Id: kAvlEnum.h 29 2009-07-01 20:30:29Z bird $ */ +/** @file + * kAvlTmpl - Templated AVL Trees, Node Enumeration. + */ + +/* + * Copyright (c) 1999-2009 Knut St. Osmundsen <bird-kStuff-spamix@anduin.net> + * + * Permission is hereby granted, free of charge, to any person + * obtaining a copy of this software and associated documentation + * files (the "Software"), to deal in the Software without + * restriction, including without limitation the rights to use, + * copy, modify, merge, publish, distribute, sublicense, and/or sell + * copies of the Software, and to permit persons to whom the + * Software is furnished to do so, subject to the following + * conditions: + * + * The above copyright notice and this permission notice shall be + * included in all copies or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, + * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES + * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND + * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT + * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, + * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING + * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR + * OTHER DEALINGS IN THE SOFTWARE. + */ + +/******************************************************************************* +* Structures and Typedefs * +*******************************************************************************/ +/** + * Enumeration control data. + * + * This is initialized by BeginEnum and used by GetNext to figure out what + * to do next. + */ +typedef struct KAVL_TYPE(,ENUMDATA) +{ + KBOOL fFromLeft; + KI8 cEntries; + KU8 achFlags[KAVL_MAX_STACK]; + KAVLNODE * aEntries[KAVL_MAX_STACK]; +} KAVL_TYPE(,ENUMDATA), *KAVL_TYPE(P,ENUMDATA); + + +/** + * Ends an enumeration. + * + * The purpose of this function is to unlock the tree should the + * AVL implementation include locking. It's good practice to call + * it anyway even if the tree doesn't do any locking. + * + * @param pEnumData Pointer to enumeration control data. + */ +KAVL_DECL(void) KAVL_FN(EndEnum)(KAVL_TYPE(,ENUMDATA) *pEnumData) +{ + KAVLROOT pRoot = pEnumData->pRoot; + pEnumData->pRoot = NULL; + if (pRoot) + KAVL_READ_UNLOCK(pEnumData->pRoot); +} + + +/** + * Get the next node in the tree enumeration. + * + * The current implementation of this function willl not walk the mpList + * chain like the DoWithAll function does. This may be changed later. + * + * @returns Pointer to the next node in the tree. + * NULL is returned when the end of the tree has been reached, + * it is not necessary to call EndEnum in this case. + * @param pEnumData Pointer to enumeration control data. + */ +KAVL_DECL(KAVLNODE *) KAVL_FN(GetNext)(KAVL_TYPE(,ENUMDATA) *pEnumData) +{ + if (pEnumData->fFromLeft) + { /* from left */ + while (pEnumData->cEntries > 0) + { + KAVLNODE *pNode = pEnumData->aEntries[pEnumData->cEntries - 1]; + + /* left */ + if (pEnumData->achFlags[pEnumData->cEntries - 1] == 0) + { + pEnumData->achFlags[pEnumData->cEntries - 1]++; + if (pNode->mpLeft != KAVL_NULL) + { + pEnumData->achFlags[pEnumData->cEntries] = 0; /* 0 left, 1 center, 2 right */ + pEnumData->aEntries[pEnumData->cEntries++] = KAVL_GET_POINTER(&pNode->mpLeft); + continue; + } + } + + /* center */ + if (pEnumData->achFlags[pEnumData->cEntries - 1] == 1) + { + pEnumData->achFlags[pEnumData->cEntries - 1]++; + return pNode; + } + + /* right */ + pEnumData->cEntries--; + if (pNode->mpRight != KAVL_NULL) + { + pEnumData->achFlags[pEnumData->cEntries] = 0; + pEnumData->aEntries[pEnumData->cEntries++] = KAVL_GET_POINTER(&pNode->mpRight); + } + } /* while */ + } + else + { /* from right */ + while (pEnumData->cEntries > 0) + { + KAVLNODE *pNode = pEnumData->aEntries[pEnumData->cEntries - 1]; + + /* right */ + if (pEnumData->achFlags[pEnumData->cEntries - 1] == 0) + { + pEnumData->achFlags[pEnumData->cEntries - 1]++; + if (pNode->mpRight != KAVL_NULL) + { + pEnumData->achFlags[pEnumData->cEntries] = 0; /* 0 right, 1 center, 2 left */ + pEnumData->aEntries[pEnumData->cEntries++] = KAVL_GET_POINTER(&pNode->mpRight); + continue; + } + } + + /* center */ + if (pEnumData->achFlags[pEnumData->cEntries - 1] == 1) + { + pEnumData->achFlags[pEnumData->cEntries - 1]++; + return pNode; + } + + /* left */ + pEnumData->cEntries--; + if (pNode->mpLeft != KAVL_NULL) + { + pEnumData->achFlags[pEnumData->cEntries] = 0; + pEnumData->aEntries[pEnumData->cEntries++] = KAVL_GET_POINTER(&pNode->mpLeft); + } + } /* while */ + } + + /* + * Call EndEnum. + */ + KAVL_FN(EndEnum)(pEnumData); + return NULL; +} + + +/** + * Starts an enumeration of all nodes in the given AVL tree. + * + * The current implementation of this function will not walk the mpList + * chain like the DoWithAll function does. This may be changed later. + * + * @returns Pointer to the first node in the enumeration. + * If NULL is returned the tree is empty calling EndEnum isn't + * strictly necessary (although it will do no harm). + * @param pRoot Pointer to the AVL-tree root structure. + * @param pEnumData Pointer to enumeration control data. + * @param fFromLeft K_TRUE: Left to right. + * K_FALSE: Right to left. + */ +KAVL_DECL(KAVLNODE *) KAVL_FN(BeginEnum)(KAVLROOT *pRoot, KAVL_TYPE(,ENUMDATA) *pEnumData, KBOOL fFromLeft) +{ + KAVL_READ_LOCK(pRoot); + pEnumData->pRoot = pRoot; + if (pRoot->mpRoot != KAVL_NULL) + { + pEnumData->fFromLeft = fFromLeft; + pEnumData->cEntries = 1; + pEnumData->aEntries[0] = KAVL_GET_POINTER(pRoot->mpRoot); + pEnumData->achFlags[0] = 0; + } + else + pEnumData->cEntries = 0; + + return KAVL_FN(GetNext)(pEnumData); +} + |