85 lines
2.2 KiB
C
85 lines
2.2 KiB
C
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/*
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** 2008 September 1
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**
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** The author disclaims copyright to this source code. In place of
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** a legal notice, here is a blessing:
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**
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** May you do good and not evil.
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** May you find forgiveness for yourself and forgive others.
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** May you share freely, never taking more than you give.
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**
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*************************************************************************
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**
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** The code in this file contains sample implementations of the
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** sqlite3_wsd_init() and sqlite3_wsd_find() functions required if the
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** SQLITE_OMIT_WSD symbol is defined at build time.
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*/
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#if defined(SQLITE_OMIT_WSD) && defined(SQLITE_TEST)
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#include "sqliteInt.h"
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#define PLS_HASHSIZE 43
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typedef struct ProcessLocalStorage ProcessLocalStorage;
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typedef struct ProcessLocalVar ProcessLocalVar;
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struct ProcessLocalStorage {
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ProcessLocalVar *aData[PLS_HASHSIZE];
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int nFree;
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u8 *pFree;
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};
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struct ProcessLocalVar {
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void *pKey;
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ProcessLocalVar *pNext;
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};
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static ProcessLocalStorage *pGlobal = 0;
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int sqlite3_wsd_init(int N, int J){
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if( !pGlobal ){
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int nMalloc = N + sizeof(ProcessLocalStorage) + J*sizeof(ProcessLocalVar);
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pGlobal = (ProcessLocalStorage *)malloc(nMalloc);
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if( pGlobal ){
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memset(pGlobal, 0, sizeof(ProcessLocalStorage));
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pGlobal->nFree = nMalloc - sizeof(ProcessLocalStorage);
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pGlobal->pFree = (u8 *)&pGlobal[1];
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}
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}
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return pGlobal ? SQLITE_OK : SQLITE_NOMEM;
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}
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void *sqlite3_wsd_find(void *K, int L){
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int i;
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int iHash = 0;
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ProcessLocalVar *pVar;
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/* Calculate a hash of K */
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for(i=0; i<sizeof(void*); i++){
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iHash = (iHash<<3) + ((unsigned char *)&K)[i];
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}
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iHash = iHash%PLS_HASHSIZE;
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/* Search the hash table for K. */
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for(pVar=pGlobal->aData[iHash]; pVar && pVar->pKey!=K; pVar=pVar->pNext);
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/* If no entry for K was found, create and populate a new one. */
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if( !pVar ){
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int nByte = ROUND8(sizeof(ProcessLocalVar) + L);
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assert( pGlobal->nFree>=nByte );
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pVar = (ProcessLocalVar *)pGlobal->pFree;
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pVar->pKey = K;
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pVar->pNext = pGlobal->aData[iHash];
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pGlobal->aData[iHash] = pVar;
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pGlobal->nFree -= nByte;
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pGlobal->pFree += nByte;
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memcpy(&pVar[1], K, L);
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}
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return (void *)&pVar[1];
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}
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#endif
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