361   unsigned char *aData;  in openTransaction()  local
366   aData = sqlite3_malloc(pMain->nPagesize);  in openTransaction()
371   if( !pMain->pWritable || !pMain->aCksum || !aData ){  in openTransaction()
383     rc = sqlite3OsRead(p, aData, pMain->nPagesize, 0);  in openTransaction()
385       u32 nDbsize = decodeUint32(&aData[28]);  in openTransaction()
386       if( nDbsize>0 && memcmp(&aData[24], &aData[92], 4)==0 ){  in openTransaction()
393     iTrunk = decodeUint32(&aData[32]);  in openTransaction()
398       rc = sqlite3OsRead(p, aData, pMain->nPagesize, iOff);  in openTransaction()
399       nLeaf = decodeUint32(&aData[4]);  in openTransaction()
401         u32 pgno = decodeUint32(&aData[8+4*iLeaf]);  in openTransaction()
404       iTrunk = decodeUint32(aData);  in openTransaction()
413         rc = sqlite3OsRead(pMain->pReal, aData, pMain->nPagesize, iOff);  in openTransaction()
414         pMain->aCksum[ii] = genCksum(aData, pMain->nPagesize);  in openTransaction()
424   sqlite3_free(aData);  in openTransaction()