| 1 | /* $Id: strspace.cpp 4071 2007-08-07 17:07:59Z vboxsync $ */
|
|---|
| 2 | /** @file
|
|---|
| 3 | * innotek Portable Runtime - Unique String Spaces.
|
|---|
| 4 | */
|
|---|
| 5 |
|
|---|
| 6 | /*
|
|---|
| 7 | * Copyright (C) 2006-2007 innotek GmbH
|
|---|
| 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 as published by the Free Software Foundation,
|
|---|
| 13 | * in version 2 as it comes in the "COPYING" file of the VirtualBox OSE
|
|---|
| 14 | * distribution. VirtualBox OSE is distributed in the hope that it will
|
|---|
| 15 | * be useful, but WITHOUT ANY WARRANTY of any kind.
|
|---|
| 16 | */
|
|---|
| 17 |
|
|---|
| 18 |
|
|---|
| 19 | /*******************************************************************************
|
|---|
| 20 | * Header Files *
|
|---|
| 21 | *******************************************************************************/
|
|---|
| 22 | #include <iprt/string.h>
|
|---|
| 23 | #include <iprt/assert.h>
|
|---|
| 24 |
|
|---|
| 25 |
|
|---|
| 26 | /*******************************************************************************
|
|---|
| 27 | * Defined Constants And Macros *
|
|---|
| 28 | *******************************************************************************/
|
|---|
| 29 | /*
|
|---|
| 30 | * AVL configuration.
|
|---|
| 31 | */
|
|---|
| 32 | #define KAVL_FN(a) rtstrspace##a
|
|---|
| 33 | #define KAVL_MAX_STACK 27 /* Up to 2^24 nodes. */
|
|---|
| 34 | #define KAVL_EQUAL_ALLOWED 1
|
|---|
| 35 | #define KAVLNODECORE RTSTRSPACECORE
|
|---|
| 36 | #define PKAVLNODECORE PRTSTRSPACECORE
|
|---|
| 37 | #define PPKAVLNODECORE PPRTSTRSPACECORE
|
|---|
| 38 | #define KAVLKEY uint32_t
|
|---|
| 39 | #define PKAVLKEY uint32_t *
|
|---|
| 40 |
|
|---|
| 41 | #define PKAVLCALLBACK PFNRTSTRSPACECALLBACK
|
|---|
| 42 |
|
|---|
| 43 | /*
|
|---|
| 44 | * AVL Compare macros
|
|---|
| 45 | */
|
|---|
| 46 | #define KAVL_G(key1, key2) (key1 > key2)
|
|---|
| 47 | #define KAVL_E(key1, key2) (key1 == key2)
|
|---|
| 48 | #define KAVL_NE(key1, key2) (key1 != key2)
|
|---|
| 49 |
|
|---|
| 50 |
|
|---|
| 51 | /*
|
|---|
| 52 | * Include the code.
|
|---|
| 53 | */
|
|---|
| 54 | #define SSToDS(ptr) ptr
|
|---|
| 55 | #define KMAX RT_MAX
|
|---|
| 56 | #define kASSERT Assert
|
|---|
| 57 | #include "table/avl_Base.cpp.h"
|
|---|
| 58 | #include "table/avl_Get.cpp.h"
|
|---|
| 59 | #include "table/avl_DoWithAll.cpp.h"
|
|---|
| 60 | #include "table/avl_Destroy.cpp.h"
|
|---|
| 61 |
|
|---|
| 62 |
|
|---|
| 63 |
|
|---|
| 64 | /* sdbm:
|
|---|
| 65 | This algorithm was created for sdbm (a public-domain reimplementation of
|
|---|
| 66 | ndbm) database library. it was found to do well in scrambling bits,
|
|---|
| 67 | causing better distribution of the keys and fewer splits. it also happens
|
|---|
| 68 | to be a good general hashing function with good distribution. the actual
|
|---|
| 69 | function is hash(i) = hash(i - 1) * 65599 + str[i]; what is included below
|
|---|
| 70 | is the faster version used in gawk. [there is even a faster, duff-device
|
|---|
| 71 | version] the magic constant 65599 was picked out of thin air while
|
|---|
| 72 | experimenting with different constants, and turns out to be a prime.
|
|---|
| 73 | this is one of the algorithms used in berkeley db (see sleepycat) and
|
|---|
| 74 | elsewhere. */
|
|---|
| 75 | inline uint32_t sdbm(const char *str, size_t *pcch)
|
|---|
| 76 | {
|
|---|
| 77 | uint8_t *pu8 = (uint8_t *)str;
|
|---|
| 78 | uint32_t hash = 0;
|
|---|
| 79 | int c;
|
|---|
| 80 |
|
|---|
| 81 | while ((c = *pu8++))
|
|---|
| 82 | hash = c + (hash << 6) + (hash << 16) - hash;
|
|---|
| 83 |
|
|---|
| 84 | *pcch = (uintptr_t)pu8 - (uintptr_t)str;
|
|---|
| 85 | return hash;
|
|---|
| 86 | }
|
|---|
| 87 |
|
|---|
| 88 |
|
|---|
| 89 | /**
|
|---|
| 90 | * Inserts a string into a unique string space.
|
|---|
| 91 | *
|
|---|
| 92 | * @returns true on success.
|
|---|
| 93 | * @returns false if the string collieded with an existing string.
|
|---|
| 94 | * @param pStrSpace The space to insert it into.
|
|---|
| 95 | * @param pStr The string node.
|
|---|
| 96 | */
|
|---|
| 97 | RTDECL(bool) RTStrSpaceInsert(PRTSTRSPACE pStrSpace, PRTSTRSPACECORE pStr)
|
|---|
| 98 | {
|
|---|
| 99 | pStr->Key = sdbm(pStr->pszString, &pStr->cchString);
|
|---|
| 100 | PRTSTRSPACECORE pMatch = KAVL_FN(Get)(pStrSpace, pStr->Key);
|
|---|
| 101 | if (!pMatch)
|
|---|
| 102 | return KAVL_FN(Insert)(pStrSpace, pStr);
|
|---|
| 103 |
|
|---|
| 104 | /* Check for clashes. */
|
|---|
| 105 | for (PRTSTRSPACECORE pCur = pMatch; pCur; pCur = pCur->pList)
|
|---|
| 106 | if ( pCur->cchString == pStr->cchString
|
|---|
| 107 | && !memcmp(pCur->pszString, pStr->pszString, pStr->cchString))
|
|---|
| 108 | return false;
|
|---|
| 109 | pStr->pList = pMatch->pList;
|
|---|
| 110 | pMatch->pList = pStr;
|
|---|
| 111 | return false;
|
|---|
| 112 | }
|
|---|
| 113 |
|
|---|
| 114 |
|
|---|
| 115 | /**
|
|---|
| 116 | * Removes a string from a unique string space.
|
|---|
| 117 | *
|
|---|
| 118 | * @returns Pointer to the removed string node.
|
|---|
| 119 | * @returns NULL if the string was not found in the string space.
|
|---|
| 120 | * @param pStrSpace The space to insert it into.
|
|---|
| 121 | * @param pszString The string to remove.
|
|---|
| 122 | */
|
|---|
| 123 | RTDECL(PRTSTRSPACECORE) RTStrSpaceRemove(PRTSTRSPACE pStrSpace, const char *pszString)
|
|---|
| 124 | {
|
|---|
| 125 | size_t cchString;
|
|---|
| 126 | KAVLKEY Key = sdbm(pszString, &cchString);
|
|---|
| 127 | PRTSTRSPACECORE pCur = KAVL_FN(Get)(pStrSpace, Key);
|
|---|
| 128 | if (!pCur)
|
|---|
| 129 | return NULL;
|
|---|
| 130 |
|
|---|
| 131 | /* find the right one. */
|
|---|
| 132 | PRTSTRSPACECORE pPrev = NULL;
|
|---|
| 133 | for (; pCur; pPrev = pCur, pCur = pCur->pList)
|
|---|
| 134 | if ( pCur->cchString == cchString
|
|---|
| 135 | && !memcmp(pCur->pszString, pszString, cchString))
|
|---|
| 136 | break;
|
|---|
| 137 | if (pCur)
|
|---|
| 138 | {
|
|---|
| 139 | if (pPrev)
|
|---|
| 140 | /* simple, it's in the linked list. */
|
|---|
| 141 | pPrev->pList = pCur->pList;
|
|---|
| 142 | else
|
|---|
| 143 | {
|
|---|
| 144 | /* in the tree. remove and reinsert list head. */
|
|---|
| 145 | PRTSTRSPACECORE pInsert = pCur->pList;
|
|---|
| 146 | pCur->pList = NULL;
|
|---|
| 147 | pCur = KAVL_FN(Remove)(pStrSpace, Key);
|
|---|
| 148 | Assert(pCur);
|
|---|
| 149 | if (pInsert)
|
|---|
| 150 | {
|
|---|
| 151 | PRTSTRSPACECORE pList = pInsert->pList;
|
|---|
| 152 | bool fRc = KAVL_FN(Insert)(pStrSpace, pInsert);
|
|---|
| 153 | Assert(fRc); NOREF(fRc);
|
|---|
| 154 | pInsert->pList = pList;
|
|---|
| 155 | }
|
|---|
| 156 | }
|
|---|
| 157 | }
|
|---|
| 158 |
|
|---|
| 159 | return pCur;
|
|---|
| 160 | }
|
|---|
| 161 |
|
|---|
| 162 |
|
|---|
| 163 | /**
|
|---|
| 164 | * Gets a string from a unique string space.
|
|---|
| 165 | *
|
|---|
| 166 | * @returns Pointer to the string node.
|
|---|
| 167 | * @returns NULL if the string was not found in the string space.
|
|---|
| 168 | * @param pStrSpace The space to insert it into.
|
|---|
| 169 | * @param pszString The string to get.
|
|---|
| 170 | */
|
|---|
| 171 | RTDECL(PRTSTRSPACECORE) RTStrSpaceGet(PRTSTRSPACE pStrSpace, const char *pszString)
|
|---|
| 172 | {
|
|---|
| 173 | size_t cchString;
|
|---|
| 174 | KAVLKEY Key = sdbm(pszString, &cchString);
|
|---|
| 175 | PRTSTRSPACECORE pCur = KAVL_FN(Get)(pStrSpace, Key);
|
|---|
| 176 | if (!pCur)
|
|---|
| 177 | return NULL;
|
|---|
| 178 |
|
|---|
| 179 | /* Linear search. */
|
|---|
| 180 | for (; pCur; pCur = pCur->pList)
|
|---|
| 181 | if ( pCur->cchString == cchString
|
|---|
| 182 | && !memcmp(pCur->pszString, pszString, cchString))
|
|---|
| 183 | return pCur;
|
|---|
| 184 | return NULL;
|
|---|
| 185 | }
|
|---|
| 186 |
|
|---|
| 187 |
|
|---|
| 188 |
|
|---|
| 189 | /**
|
|---|
| 190 | * Enumerates the string space.
|
|---|
| 191 | * The caller supplies a callback which will be called for each of
|
|---|
| 192 | * the string nodes.
|
|---|
| 193 | *
|
|---|
| 194 | * @returns 0 or what ever non-zero return value pfnCallback returned
|
|---|
| 195 | * when aborting the destruction.
|
|---|
| 196 | * @param pStrSpace The space to insert it into.
|
|---|
| 197 | * @param pfnCallback The callback.
|
|---|
| 198 | * @param pvUser The user argument.
|
|---|
| 199 | */
|
|---|
| 200 | RTDECL(int) RTStrSpaceEnumerate(PRTSTRSPACE pStrSpace, PFNRTSTRSPACECALLBACK pfnCallback, void *pvUser)
|
|---|
| 201 | {
|
|---|
| 202 | return KAVL_FN(DoWithAll)(pStrSpace, true, pfnCallback, pvUser);
|
|---|
| 203 | }
|
|---|
| 204 |
|
|---|
| 205 |
|
|---|
| 206 | /**
|
|---|
| 207 | * Destroys the string space.
|
|---|
| 208 | * The caller supplies a callback which will be called for each of
|
|---|
| 209 | * the string nodes in for freeing their memory and other resources.
|
|---|
| 210 | *
|
|---|
| 211 | * @returns 0 or what ever non-zero return value pfnCallback returned
|
|---|
| 212 | * when aborting the destruction.
|
|---|
| 213 | * @param pStrSpace The space to insert it into.
|
|---|
| 214 | * @param pfnCallback The callback.
|
|---|
| 215 | * @param pvUser The user argument.
|
|---|
| 216 | */
|
|---|
| 217 | RTDECL(int) RTStrSpaceDestroy(PRTSTRSPACE pStrSpace, PFNRTSTRSPACECALLBACK pfnCallback, void *pvUser)
|
|---|
| 218 | {
|
|---|
| 219 | return KAVL_FN(Destroy)(pStrSpace, pfnCallback, pvUser);
|
|---|
| 220 | }
|
|---|
| 221 |
|
|---|
