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sqlite3

    1: /*
    2: ** 2008 September 1
    3: **
    4: ** The author disclaims copyright to this source code.  In place of
    5: ** a legal notice, here is a blessing:
    6: **
    7: **    May you do good and not evil.
    8: **    May you find forgiveness for yourself and forgive others.
    9: **    May you share freely, never taking more than you give.
   10: **
   11: *************************************************************************
   12: **
   13: ** The code in this file contains sample implementations of the 
   14: ** sqlite3_wsd_init() and sqlite3_wsd_find() functions required if the
   15: ** SQLITE_OMIT_WSD symbol is defined at build time.
   16: */
   17: 
   18: #if defined(SQLITE_OMIT_WSD) && defined(SQLITE_TEST)
   19: 
   20: #include "sqliteInt.h"
   21: 
   22: #define PLS_HASHSIZE 43
   23: 
   24: typedef struct ProcessLocalStorage ProcessLocalStorage;
   25: typedef struct ProcessLocalVar ProcessLocalVar;
   26: 
   27: struct ProcessLocalStorage {
   28:   ProcessLocalVar *aData[PLS_HASHSIZE];
   29:   int nFree;
   30:   u8 *pFree;
   31: };
   32: 
   33: struct ProcessLocalVar {
   34:   void *pKey;
   35:   ProcessLocalVar *pNext;
   36: };
   37: 
   38: static ProcessLocalStorage *pGlobal = 0;
   39: 
   40: int sqlite3_wsd_init(int N, int J){
   41:   if( !pGlobal ){
   42:     int nMalloc = N + sizeof(ProcessLocalStorage) + J*sizeof(ProcessLocalVar);
   43:     pGlobal = (ProcessLocalStorage *)malloc(nMalloc);
   44:     if( pGlobal ){
   45:       memset(pGlobal, 0, sizeof(ProcessLocalStorage));
   46:       pGlobal->nFree = nMalloc - sizeof(ProcessLocalStorage);
   47:       pGlobal->pFree = (u8 *)&pGlobal[1];
   48:     }
   49:   }
   50: 
   51:   return pGlobal ? SQLITE_OK : SQLITE_NOMEM;
   52: }
   53: 
   54: void *sqlite3_wsd_find(void *K, int L){
   55:   int i;
   56:   int iHash = 0;
   57:   ProcessLocalVar *pVar;
   58: 
   59:   /* Calculate a hash of K */
   60:   for(i=0; i<sizeof(void*); i++){
   61:     iHash = (iHash<<3) + ((unsigned char *)&K)[i];
   62:   }
   63:   iHash = iHash%PLS_HASHSIZE;
   64: 
   65:   /* Search the hash table for K. */
   66:   for(pVar=pGlobal->aData[iHash]; pVar && pVar->pKey!=K; pVar=pVar->pNext);
   67: 
   68:   /* If no entry for K was found, create and populate a new one. */
   69:   if( !pVar ){
   70:     int nByte = ROUND8(sizeof(ProcessLocalVar) + L);
   71:     assert( pGlobal->nFree>=nByte );
   72:     pVar = (ProcessLocalVar *)pGlobal->pFree;
   73:     pVar->pKey = K;
   74:     pVar->pNext = pGlobal->aData[iHash];
   75:     pGlobal->aData[iHash] = pVar;
   76:     pGlobal->nFree -= nByte;
   77:     pGlobal->pFree += nByte;
   78:     memcpy(&pVar[1], K, L);
   79:   }
   80: 
   81:   return (void *)&pVar[1];
   82: }
   83: 
   84: #endif