src/test_wsd.c

   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