SQLite

  int iIndex = 0;

  UNUSED_PARAMETER(pCtx);
  if( argc==5 ){
    iIndex = atoi(argv[4]);
    argc--;
  }
  
  *ppVtab = 0;

  /* The user should specify a single argument - the name of an fts3 table. */
  if( argc!=4 ){
    sqlite3Fts3ErrMsg(pzErr,
        "wrong number of arguments to fts4term constructor"
    );
    return SQLITE_ERROR;
  }

  zDb = argv[1]; 
  nDb = (int)strlen(zDb);
  zFts3 = argv[3];
  nFts3 = (int)strlen(zFts3);

  rc = sqlite3_declare_vtab(db, FTS3_TERMS_SCHEMA);
  if( rc!=SQLITE_OK ) return rc;

  nByte = sizeof(Fts3termTable);
  p = (Fts3termTable *)sqlite3Fts3MallocZero(nByte);
  if( !p ) return SQLITE_NOMEM;


  p->pFts3Tab = (Fts3Table*)sqlite3Fts3MallocZero(
      sizeof(Fts3Table) + nDb + nFts3 + 2
  );
  if( p->pFts3Tab==0 ){
    sqlite3_free(p);
    return SQLITE_NOMEM;
  }
  p->pFts3Tab->zDb = (char *)&p->pFts3Tab[1];
  p->pFts3Tab->zName = &p->pFts3Tab->zDb[nDb+1];
  p->pFts3Tab->db = db;
  p->pFts3Tab->nIndex = iIndex+1;
  p->iIndex = iIndex;

  memcpy((char *)p->pFts3Tab->zDb, zDb, nDb);

  int i;

  /* Free any prepared statements held */
  for(i=0; i<SizeofArray(pFts3->aStmt); i++){
    sqlite3_finalize(pFts3->aStmt[i]);
  }
  sqlite3_free(pFts3->zSegmentsTbl);
  sqlite3_free(pFts3);
  sqlite3_free(p);
  return SQLITE_OK;
}

#define FTS4AUX_EQ_CONSTRAINT 1
#define FTS4AUX_GE_CONSTRAINT 2
#define FTS4AUX_LE_CONSTRAINT 4

#define MAX(x,y) (((x) > (y)) ? (x) : (y))

/*
** Constants for the largest and smallest possible 64-bit signed integers.
*/
# define LARGEST_INT64  (0xffffffff|(((i64)0x7fffffff)<<32))
# define SMALLEST_INT64 (((i64)-1) - LARGEST_INT64)

/* The uptr type is an unsigned integer large enough to hold a pointer
*/
#if defined(HAVE_STDINT_H)
  typedef uintptr_t uptr;
#elif SQLITE_PTRSIZE==4
  typedef u32 uptr;
#else
  typedef u64 uptr;
#endif

#ifdef SQLITE_4_BYTE_ALIGNED_MALLOC
# define EIGHT_BYTE_ALIGNMENT(X)   ((((uptr)(X) - (uptr)0)&3)==0)
#else
# define EIGHT_BYTE_ALIGNMENT(X)   ((((uptr)(X) - (uptr)0)&7)==0)
#endif

#endif

/* Truncate very long tokens to this many bytes. Hard limit is 
** (65536-1-1-4-9)==65521 bytes. The limiting factor is the 16-bit offset
** field that occurs at the start of each leaf page (see fts5_index.c). */
#define FTS5_MAX_TOKEN_SIZE 32768

    ** table, missing row, non-blob/text in block column - indicate 
    ** backing store corruption.  */
    if( rc==SQLITE_ERROR ) rc = FTS5_CORRUPT;

    if( rc==SQLITE_OK ){
      u8 *aOut = 0;               /* Read blob data into this buffer */
      int nByte = sqlite3_blob_bytes(p->pReader);
      int szData = (sizeof(Fts5Data) + 7) & ~7;
      sqlite3_int64 nAlloc = szData + nByte + FTS5_DATA_PADDING;
      pRet = (Fts5Data*)sqlite3_malloc64(nAlloc);
      if( pRet ){
        pRet->nn = nByte;
        aOut = pRet->p = (u8*)pRet + szData;
      }else{
        rc = SQLITE_NOMEM;
      }

      if( rc==SQLITE_OK ){
        rc = sqlite3_blob_read(p->pReader, aOut, nByte, 0);
      }

      }
    }
    p->rc = rc;
    p->nRead++;
  }

  assert( (pRet==0)==(p->rc!=SQLITE_OK) );
  assert( pRet==0 || EIGHT_BYTE_ALIGNMENT( pRet->p ) );
  return pRet;
}


/*
** Release a reference to data record returned by an earlier call to
** fts5DataRead().

    pIdx->aSample = sqlite3DbMallocZero(db, nByte);
    if( pIdx->aSample==0 ){
      sqlite3_finalize(pStmt);
      return SQLITE_NOMEM_BKPT;
    }
    pSpace = (tRowcnt*)&pIdx->aSample[nSample];
    assert( EIGHT_BYTE_ALIGNMENT( pSpace ) );
    pIdx->aAvgEq = pSpace; pSpace += nIdxCol;
    pIdx->pTable->tabFlags |= TF_HasStat4;
    for(i=0; i<nSample; i++){
      pIdx->aSample[i].anEq = pSpace; pSpace += nIdxCol;
      pIdx->aSample[i].anLt = pSpace; pSpace += nIdxCol;
      pIdx->aSample[i].anDLt = pSpace; pSpace += nIdxCol;
    }

  }else{
    *ppPage = p = (PgHdr *)sqlite3MallocZero(sizeof(PgHdr) + pPager->nExtra);
    if( p==0 ){
      sqlite3OsUnfetch(pPager->fd, (i64)(pgno-1) * pPager->pageSize, pData);
      return SQLITE_NOMEM_BKPT;
    }
    p->pExtra = (void *)&p[1];
    assert( EIGHT_BYTE_ALIGNMENT( p->pExtra ) );
    p->flags = PGHDR_MMAP;
    p->nRef = 1;
    p->pPager = pPager;
  }

  assert( p->pExtra==(void *)&p[1] );
  assert( p->pPage==0 );

  pPgHdr = (PgHdr*)pPage->pExtra;
  assert( pPgHdr->pPage==0 );
  memset(&pPgHdr->pDirty, 0, sizeof(PgHdr) - offsetof(PgHdr,pDirty));
  pPgHdr->pPage = pPage;
  pPgHdr->pData = pPage->pBuf;
  pPgHdr->pExtra = (void *)&pPgHdr[1];
  memset(pPgHdr->pExtra, 0, 8);
  assert( EIGHT_BYTE_ALIGNMENT( pPgHdr->pExtra ) );
  pPgHdr->pCache = pCache;
  pPgHdr->pgno = pgno;
  pPgHdr->flags = PGHDR_CLEAN;
  return sqlite3PcacheFetchFinish(pCache,pgno,pPage);
}

/*

  zBulk = pCache->pBulk = sqlite3Malloc( szBulk );
  sqlite3EndBenignMalloc();
  if( zBulk ){
    int nBulk = sqlite3MallocSize(zBulk)/pCache->szAlloc;
    do{
      PgHdr1 *pX = (PgHdr1*)&zBulk[pCache->szPage];
      pX->page.pBuf = zBulk;
      pX->page.pExtra = (u8*)pX + ROUND8(sizeof(*pX));
      assert( EIGHT_BYTE_ALIGNMENT( pX->page.pExtra ) );
      pX->isBulkLocal = 1;
      pX->isAnchor = 0;
      pX->pNext = pCache->pFree;
      pX->pLruPrev = 0;           /* Initializing this saves a valgrind error */
      pCache->pFree = pX;
      zBulk += pCache->szAlloc;
    }while( --nBulk );

    if( benignMalloc ){ sqlite3EndBenignMalloc(); }
#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
    pcache1EnterMutex(pCache->pGroup);
#endif
    if( pPg==0 ) return 0;
    p = (PgHdr1 *)&((u8 *)pPg)[pCache->szPage];
    p->page.pBuf = pPg;
    p->page.pExtra = (u8*)p + ROUND8(sizeof(*p));
    assert( EIGHT_BYTE_ALIGNMENT( p->page.pExtra ) );
    p->isBulkLocal = 0;
    p->isAnchor = 0;
    p->pLruPrev = 0;           /* Initializing this saves a valgrind error */
  }
  (*pCache->pnPurgeable)++;
  return p;
}

#define TESTPCACHE_CLEAR  0xd42670d4

/*
** Private implementation of a page cache.
*/
typedef struct testpcache testpcache;
struct testpcache {
  sqlite3_int64 szPage;     /* Size of each page.  Multiple of 8. */
  int szExtra;              /* Size of extra data that accompanies each page */
  int bPurgeable;           /* True if the page cache is purgeable */
  int nFree;                /* Number of unused slots in a[] */
  int nPinned;              /* Number of pinned slots in a[] */
  unsigned iRand;           /* State of the PRNG */
  unsigned iMagic;          /* Magic number for sanity checking */
  struct testpcachePage {

){
  int nMem;
  char *x;
  testpcache *p;
  int i;
  assert( testpcacheGlobal.pDummy!=0 );
  szPage = (szPage+7)&~7;
  szExtra = (szPage+7)&~7;
  nMem = sizeof(testpcache) + TESTPCACHE_NPAGE*(szPage+szExtra);
  p = sqlite3_malloc( nMem );
  if( p==0 ) return 0;
  x = (char*)&p[1];
  p->szPage = szPage;
  p->szExtra = szExtra;
  p->nFree = TESTPCACHE_NPAGE;

** sqlite3_context only happens once, instead of on each call to the
** step function.
*/
case OP_AggInverse:
case OP_AggStep: {
  int n;
  sqlite3_context *pCtx;
  u64 nAlloc;

  assert( pOp->p4type==P4_FUNCDEF );
  n = pOp->p5;
  assert( pOp->p3>0 && pOp->p3<=(p->nMem+1 - p->nCursor) );
  assert( n==0 || (pOp->p2>0 && pOp->p2+n<=(p->nMem+1 - p->nCursor)+1) );
  assert( pOp->p3<pOp->p2 || pOp->p3>=pOp->p2+n );

  /* Allocate space for (a) the context object and (n-1) extra pointers
  ** to append to the sqlite3_context.argv[1] array, and (b) a memory
  ** cell in which to store the accumulation. Be careful that the memory
  ** cell is 8-byte aligned, even on platforms where a pointer is 32-bits.
  **
  ** Note: We could avoid this by using a regular memory cell from aMem[] for 
  ** the accumulator, instead of allocating one here. */
  nAlloc = ROUND8P( sizeof(pCtx[0]) + (n-1)*sizeof(sqlite3_value*) );
  pCtx = sqlite3DbMallocRawNN(db, nAlloc + sizeof(Mem));

  if( pCtx==0 ) goto no_mem;

  pCtx->pOut = (Mem*)((u8*)pCtx + nAlloc);
  assert( EIGHT_BYTE_ALIGNMENT(pCtx->pOut) );

  sqlite3VdbeMemInit(pCtx->pOut, db, MEM_Null);
  pCtx->pMem = 0;
  pCtx->pFunc = pOp->p4.pFunc;
  pCtx->iOp = (int)(pOp - aOp);
  pCtx->pVdbe = p;
  pCtx->skipFlag = 0;
  pCtx->isError = 0;
  pCtx->enc = encoding;
  pCtx->argc = n;