SQLite

  if( pCur->pFullScan ){
    *pRowid = sqlite3_column_int64(pCur->pFullScan, 4);
  }else{
    *pRowid = pCur->a[pCur->iRow].iRowid;
  }
  return SQLITE_OK;
}

/*
** This function is called by the xUpdate() method. It returns a string
** containing the conflict mode that xUpdate() should use for the current
** operation. One of: "ROLLBACK", "IGNORE", "ABORT" or "REPLACE".
*/
static const char *spellfix1GetConflict(sqlite3 *db){
  static const char *azConflict[] = {
    /* Note: Instead of "FAIL" - "ABORT". */
    "ROLLBACK", "IGNORE", "ABORT", "ABORT", "REPLACE"
  };
  int eConflict = sqlite3_vtab_on_conflict(db);

  assert( eConflict==SQLITE_ROLLBACK || eConflict==SQLITE_IGNORE
       || eConflict==SQLITE_FAIL || eConflict==SQLITE_ABORT
       || eConflict==SQLITE_REPLACE
  );
  assert( SQLITE_ROLLBACK==1 );
  assert( SQLITE_IGNORE==2 );
  assert( SQLITE_FAIL==3 );
  assert( SQLITE_ABORT==4 );
  assert( SQLITE_REPLACE==5 );

  return azConflict[eConflict-1];
}

/*
** The xUpdate() method.
*/
static int spellfix1Update(
  sqlite3_vtab *pVTab,
  int argc,

    int iRank = sqlite3_value_int(argv[SPELLFIX_COL_RANK+2]);
    const unsigned char *zSoundslike =
           sqlite3_value_text(argv[SPELLFIX_COL_SOUNDSLIKE+2]);
    int nSoundslike = sqlite3_value_bytes(argv[SPELLFIX_COL_SOUNDSLIKE+2]);
    char *zK1, *zK2;
    int i;
    char c;
    const char *zConflict = spellfix1GetConflict(db);

    if( zWord==0 ){
      /* Inserts of the form:  INSERT INTO table(command) VALUES('xyzzy');
      ** cause zWord to be NULL, so we look at the "command" column to see
      ** what special actions to take */
      const char *zCmd = 
         (const char*)sqlite3_value_text(argv[SPELLFIX_COL_COMMAND+2]);

               "VALUES(%d,%d,%Q,%Q,%Q)",
               p->zDbName, p->zTableName,
               iRank, iLang, zWord, zK1, zK2
        );
      }else{
        newRowid = sqlite3_value_int64(argv[1]);
        spellfix1DbExec(&rc, db,
            "INSERT OR %s INTO \"%w\".\"%w_vocab\"(id,rank,langid,word,k1,k2) "
            "VALUES(%lld,%d,%d,%Q,%Q,%Q)",
            zConflict, p->zDbName, p->zTableName,
            newRowid, iRank, iLang, zWord, zK1, zK2
        );
      }
      *pRowid = sqlite3_last_insert_rowid(db);
    }else{
      rowid = sqlite3_value_int64(argv[0]);
      newRowid = *pRowid = sqlite3_value_int64(argv[1]);
      spellfix1DbExec(&rc, db,
             "UPDATE OR %s \"%w\".\"%w_vocab\" SET id=%lld, rank=%d, langid=%d,"
             " word=%Q, k1=%Q, k2=%Q WHERE id=%lld",
             zConflict, p->zDbName, p->zTableName, newRowid, iRank, iLang,
             zWord, zK1, zK2, rowid
      );
    }
    sqlite3_free(zK1);
    sqlite3_free(zK2);
  }
  return rc;

*/
static void invalidateIncrblobCursors(
  Btree *pBtree,          /* The database file to check */
  i64 iRow,               /* The rowid that might be changing */
  int isClearTable        /* True if all rows are being deleted */
){
  BtCursor *p;
  if( pBtree->hasIncrblobCur==0 ) return;
  assert( sqlite3BtreeHoldsMutex(pBtree) );
  pBtree->hasIncrblobCur = 0;
  for(p=pBtree->pBt->pCursor; p; p=p->pNext){
    if( (p->curFlags & BTCF_Incrblob)!=0 ){
      pBtree->hasIncrblobCur = 1;
      if( isClearTable || p->info.nKey==iRow ){

        p->eState = CURSOR_INVALID;
      }
    }
  }
}

#else
  /* Stub function when INCRBLOB is omitted */
  #define invalidateIncrblobCursors(x,y,z)

** the page, 1 means the second cell, and so forth) return a pointer
** to the cell content.
**
** This routine works only for pages that do not contain overflow cells.
*/
#define findCell(P,I) \
  ((P)->aData + ((P)->maskPage & get2byte(&(P)->aCellIdx[2*(I)])))























/*
** This is common tail processing for btreeParseCellPtr() and
** btreeParseCellPtrIndex() for the case when the cell does not fit entirely
** on a single B-tree page.  Make necessary adjustments to the CellInfo
** structure.
*/

** from the free-list.
**
** If no suitable space can be found on the free-list, return NULL.
**
** This function may detect corruption within pPg.  If corruption is
** detected then *pRc is set to SQLITE_CORRUPT and NULL is returned.
**
** Slots on the free list that are between 1 and 3 bytes larger than nByte
** will be ignored if adding the extra space to the fragmentation count
** causes the fragmentation count to exceed 60.

*/
static u8 *pageFindSlot(MemPage *pPg, int nByte, int *pRc){
  const int hdr = pPg->hdrOffset;
  u8 * const aData = pPg->aData;
  int iAddr = hdr + 1;
  int pc = get2byte(&aData[iAddr]);
  int x;
  int usableSize = pPg->pBt->usableSize;


  assert( pc>0 );
  do{
    int size;            /* Size of the free slot */
    /* EVIDENCE-OF: R-06866-39125 Freeblocks are always connected in order of
    ** increasing offset. */
    if( pc>usableSize-4 || pc<iAddr+4 ){
      *pRc = SQLITE_CORRUPT_BKPT;
      return 0;
    }
    /* EVIDENCE-OF: R-22710-53328 The third and fourth bytes of each
    ** freeblock form a big-endian integer which is the size of the freeblock
    ** in bytes, including the 4-byte header. */
    size = get2byte(&aData[pc+2]);

    if( (x = size - nByte)>=0 ){
      testcase( x==4 );
      testcase( x==3 );
      if( pc < pPg->cellOffset+2*pPg->nCell || size+pc > usableSize ){
        *pRc = SQLITE_CORRUPT_BKPT;
        return 0;
      }else if( x<4 ){
        /* EVIDENCE-OF: R-11498-58022 In a well-formed b-tree page, the total
        ** number of bytes in fragments may not exceed 60. */
        if( aData[hdr+7]>57 ) return 0;



        /* Remove the slot from the free-list. Update the number of
        ** fragmented bytes within the page. */
        memcpy(&aData[iAddr], &aData[pc], 2);
        aData[hdr+7] += (u8)x;
      }else{
        /* The slot remains on the free-list. Reduce its size to account
         ** for the portion used by the new allocation. */
        put2byte(&aData[pc+2], x);
      }
      return &aData[pc + x];
    }
    iAddr = pc;
    pc = get2byte(&aData[pc]);
  }while( pc );

  return 0;
}

/*
** Allocate nByte bytes of space from within the B-Tree page passed
** as the first argument. Write into *pIdx the index into pPage->aData[]

  gap = pPage->cellOffset + 2*pPage->nCell;
  assert( gap<=65536 );
  /* EVIDENCE-OF: R-29356-02391 If the database uses a 65536-byte page size
  ** and the reserved space is zero (the usual value for reserved space)
  ** then the cell content offset of an empty page wants to be 65536.
  ** However, that integer is too large to be stored in a 2-byte unsigned
  ** integer, so a value of 0 is used in its place. */
  top = get2byte(&data[hdr+5]);
  assert( top<=pPage->pBt->usableSize ); /* Prevent by getAndInitPage() */
  if( gap>top ){

    if( top==0 && pPage->pBt->usableSize==65536 ){
      top = 65536;
    }else{
      return SQLITE_CORRUPT_BKPT;
    }
  }

  /* If there is enough space between gap and top for one more cell pointer
  ** array entry offset, and if the freelist is not empty, then search the
  ** freelist looking for a free slot big enough to satisfy the request.
  */
  testcase( gap+2==top );
  testcase( gap+1==top );
  testcase( gap==top );
  if( (data[hdr+2] || data[hdr+1]) && gap+2<=top ){

    u8 *pSpace = pageFindSlot(pPage, nByte, &rc);


    if( pSpace ){
      assert( pSpace>=data && (pSpace - data)<65536 );
      *pIdx = (int)(pSpace - data);
      return SQLITE_OK;
    }else if( rc ){
      return rc;
    }
  }

  /* The request could not be fulfilled using a freelist slot.  Check
  ** to see if defragmentation is necessary.
  */
  testcase( gap+2+nByte==top );
  if( gap+2+nByte>top ){

    assert( pPage->nCell>0 || CORRUPT_DB );
    rc = defragmentPage(pPage);
    if( rc ) return rc;
    top = get2byteNotZero(&data[hdr+5]);
    assert( gap+nByte<=top );
  }

  if( n>=mxPage ){
    return SQLITE_CORRUPT_BKPT;
  }
  if( n>0 ){
    /* There are pages on the freelist.  Reuse one of those pages. */
    Pgno iTrunk;
    u8 searchList = 0; /* If the free-list must be searched for 'nearby' */
    u32 nSearch = 0;   /* Count of the number of search attempts */
    
    /* If eMode==BTALLOC_EXACT and a query of the pointer-map
    ** shows that the page 'nearby' is somewhere on the free-list, then
    ** the entire-list will be searched for that page.
    */
#ifndef SQLITE_OMIT_AUTOVACUUM
    if( eMode==BTALLOC_EXACT ){

      }else{
        /* EVIDENCE-OF: R-59841-13798 The 4-byte big-endian integer at offset 32
        ** stores the page number of the first page of the freelist, or zero if
        ** the freelist is empty. */
        iTrunk = get4byte(&pPage1->aData[32]);
      }
      testcase( iTrunk==mxPage );
      if( iTrunk>mxPage || nSearch++ > n ){
        rc = SQLITE_CORRUPT_BKPT;
      }else{
        rc = btreeGetUnusedPage(pBt, iTrunk, &pTrunk, 0);
      }
      if( rc ){
        pTrunk = 0;
        goto end_allocate_page;

  int sz,           /* Bytes of content in pCell */
  u8 *pTemp,        /* Temp storage space for pCell, if needed */
  Pgno iChild,      /* If non-zero, replace first 4 bytes with this value */
  int *pRC          /* Read and write return code from here */
){
  int idx = 0;      /* Where to write new cell content in data[] */
  int j;            /* Loop counter */



  u8 *data;         /* The content of the whole page */
  u8 *pIns;         /* The point in pPage->aCellIdx[] where no cell inserted */

  if( *pRC ) return;

  assert( i>=0 && i<=pPage->nCell+pPage->nOverflow );
  assert( MX_CELL(pPage->pBt)<=10921 );
  assert( pPage->nCell<=MX_CELL(pPage->pBt) || CORRUPT_DB );
  assert( pPage->nOverflow<=ArraySize(pPage->apOvfl) );

    if( iChild ){
      put4byte(pCell, iChild);
    }
    j = pPage->nOverflow++;
    assert( j<(int)(sizeof(pPage->apOvfl)/sizeof(pPage->apOvfl[0])) );
    pPage->apOvfl[j] = pCell;
    pPage->aiOvfl[j] = (u16)i;

    /* When multiple overflows occur, they are always sequential and in
    ** sorted order.  This invariants arise because multiple overflows can
    ** only occur when inserting divider cells into the parent page during
    ** balancing, and the dividers are adjacent and sorted.
    */
    assert( j==0 || pPage->aiOvfl[j-1]<(u16)i ); /* Overflows in sorted order */
    assert( j==0 || i==pPage->aiOvfl[j-1]+1 );   /* Overflows are sequential */
  }else{
    int rc = sqlite3PagerWrite(pPage->pDbPage);
    if( rc!=SQLITE_OK ){
      *pRC = rc;
      return;
    }
    assert( sqlite3PagerIswriteable(pPage->pDbPage) );
    data = pPage->aData;
    assert( &data[pPage->cellOffset]==pPage->aCellIdx );


    rc = allocateSpace(pPage, sz, &idx);
    if( rc ){ *pRC = rc; return; }
    /* The allocateSpace() routine guarantees the following properties
    ** if it returns successfully */
    assert( idx >= 0 );
    assert( idx >= pPage->cellOffset+2*pPage->nCell+2 || CORRUPT_DB );
    assert( idx+sz <= (int)pPage->pBt->usableSize );

    pPage->nFree -= (u16)(2 + sz);
    memcpy(&data[idx], pCell, sz);
    if( iChild ){
      put4byte(&data[idx], iChild);
    }
    pIns = pPage->aCellIdx + i*2;
    memmove(pIns+2, pIns, 2*(pPage->nCell - i));
    put2byte(pIns, idx);
    pPage->nCell++;
    /* increment the cell count */
    if( (++data[pPage->hdrOffset+4])==0 ) data[pPage->hdrOffset+3]++;
    assert( get2byte(&data[pPage->hdrOffset+3])==pPage->nCell );
#ifndef SQLITE_OMIT_AUTOVACUUM
    if( pPage->pBt->autoVacuum ){
      /* The cell may contain a pointer to an overflow page. If so, write
      ** the entry for the overflow page into the pointer map.
      */
      ptrmapPutOvflPtr(pPage, pCell, pRC);
    }
#endif
  }
}

/*
** A CellArray object contains a cache of pointers and sizes for a
** consecutive sequence of cells that might be held multiple pages.
*/
typedef struct CellArray CellArray;
struct CellArray {
  int nCell;              /* Number of cells in apCell[] */
  MemPage *pRef;          /* Reference page */
  u8 **apCell;            /* All cells begin balanced */
  u16 *szCell;            /* Local size of all cells in apCell[] */
};

/*
** Make sure the cell sizes at idx, idx+1, ..., idx+N-1 have been
** computed.
*/
static void populateCellCache(CellArray *p, int idx, int N){
  assert( idx>=0 && idx+N<=p->nCell );
  while( N>0 ){
    assert( p->apCell[idx]!=0 );
    if( p->szCell[idx]==0 ){
      p->szCell[idx] = p->pRef->xCellSize(p->pRef, p->apCell[idx]);
    }else{
      assert( CORRUPT_DB ||
              p->szCell[idx]==p->pRef->xCellSize(p->pRef, p->apCell[idx]) );
    }
    idx++;
    N--;
  }
}

/*
** Return the size of the Nth element of the cell array
*/
static SQLITE_NOINLINE u16 computeCellSize(CellArray *p, int N){
  assert( N>=0 && N<p->nCell );
  assert( p->szCell[N]==0 );
  p->szCell[N] = p->pRef->xCellSize(p->pRef, p->apCell[N]);
  return p->szCell[N];
}
static u16 cachedCellSize(CellArray *p, int N){
  assert( N>=0 && N<p->nCell );
  if( p->szCell[N] ) return p->szCell[N];
  return computeCellSize(p, N);
}

/*
** Array apCell[] contains pointers to nCell b-tree page cells. The 
** szCell[] array contains the size in bytes of each cell. This function
** replaces the current contents of page pPg with the contents of the cell
** array.
**
** Some of the cells in apCell[] may currently be stored in pPg. This
** function works around problems caused by this by making a copy of any 
** such cells before overwriting the page data.
**
** The MemPage.nFree field is invalidated by this function. It is the 
** responsibility of the caller to set it correctly.
*/
static int rebuildPage(
  MemPage *pPg,                   /* Edit this page */
  int nCell,                      /* Final number of cells on page */
  u8 **apCell,                    /* Array of cells */
  u16 *szCell                     /* Array of cell sizes */
){
  const int hdr = pPg->hdrOffset;          /* Offset of header on pPg */
  u8 * const aData = pPg->aData;           /* Pointer to data for pPg */

  pData = pEnd;
  for(i=0; i<nCell; i++){
    u8 *pCell = apCell[i];
    if( pCell>aData && pCell<pEnd ){
      pCell = &pTmp[pCell - aData];
    }
    pData -= szCell[i];

    put2byte(pCellptr, (pData - aData));
    pCellptr += 2;
    if( pData < pCellptr ) return SQLITE_CORRUPT_BKPT;
    memcpy(pData, pCell, szCell[i]);
    assert( szCell[i]==pPg->xCellSize(pPg, pCell) || CORRUPT_DB );
    testcase( szCell[i]!=pPg->xCellSize(pPg,pCell) );
  }

  /* The pPg->nFree field is now set incorrectly. The caller will fix it. */
  pPg->nCell = nCell;
  pPg->nOverflow = 0;

  put2byte(&aData[hdr+1], 0);
  put2byte(&aData[hdr+3], pPg->nCell);
  put2byte(&aData[hdr+5], pData - aData);
  aData[hdr+7] = 0x00;
  return SQLITE_OK;
}

/*
** Array apCell[] contains nCell pointers to b-tree cells. Array szCell
** contains the size in bytes of each such cell. This function attempts to 
** add the cells stored in the array to page pPg. If it cannot (because 
** the page needs to be defragmented before the cells will fit), non-zero

** cells in apCell[], then the cells do not fit and non-zero is returned.
*/
static int pageInsertArray(
  MemPage *pPg,                   /* Page to add cells to */
  u8 *pBegin,                     /* End of cell-pointer array */
  u8 **ppData,                    /* IN/OUT: Page content -area pointer */
  u8 *pCellptr,                   /* Pointer to cell-pointer area */
  int iFirst,                     /* Index of first cell to add */
  int nCell,                      /* Number of cells to add to pPg */
  CellArray *pCArray              /* Array of cells */

){
  int i;
  u8 *aData = pPg->aData;
  u8 *pData = *ppData;
  int iEnd = iFirst + nCell;
  assert( CORRUPT_DB || pPg->hdrOffset==0 );    /* Never called on page 1 */
  for(i=iFirst; i<iEnd; i++){
    int sz, rc;

    u8 *pSlot;
    sz = cachedCellSize(pCArray, i);
    if( (aData[1]==0 && aData[2]==0) || (pSlot = pageFindSlot(pPg,sz,&rc))==0 ){
      pData -= sz;
      if( pData<pBegin ) return 1;
      pSlot = pData;
    }
    memcpy(pSlot, pCArray->apCell[i], sz);
    put2byte(pCellptr, (pSlot - aData));
    pCellptr += 2;
  }
  *ppData = pData;
  return 0;
}

/*
** Array apCell[] contains nCell pointers to b-tree cells. Array szCell 
** contains the size in bytes of each such cell. This function adds the
** space associated with each cell in the array that is currently stored 
** within the body of pPg to the pPg free-list. The cell-pointers and other
** fields of the page are not updated.
**
** This function returns the total number of cells added to the free-list.
*/
static int pageFreeArray(
  MemPage *pPg,                   /* Page to edit */
  int iFirst,                     /* First cell to delete */
  int nCell,                      /* Cells to delete */
  CellArray *pCArray              /* Array of cells */

){
  u8 * const aData = pPg->aData;
  u8 * const pEnd = &aData[pPg->pBt->usableSize];
  u8 * const pStart = &aData[pPg->hdrOffset + 8 + pPg->childPtrSize];
  int nRet = 0;
  int i;
  int iEnd = iFirst + nCell;
  u8 *pFree = 0;
  int szFree = 0;

  for(i=iFirst; i<iEnd; i++){
    u8 *pCell = pCArray->apCell[i];
    if( pCell>=pStart && pCell<pEnd ){
      int sz;
      /* No need to use cachedCellSize() here.  The sizes of all cells that
      ** are to be freed have already been computing while deciding which
      ** cells need freeing */
      sz = pCArray->szCell[i];  assert( sz>0 );
      if( pFree!=(pCell + sz) ){
        if( pFree ){
          assert( pFree>aData && (pFree - aData)<65536 );
          freeSpace(pPg, (u16)(pFree - aData), szFree);
        }
        pFree = pCell;
        szFree = sz;

**
** This routine makes the necessary adjustments to pPg so that it contains
** the correct cells after being balanced.
**
** The pPg->nFree field is invalid when this function returns. It is the
** responsibility of the caller to set it correctly.
*/
static int editPage(
  MemPage *pPg,                   /* Edit this page */
  int iOld,                       /* Index of first cell currently on page */
  int iNew,                       /* Index of new first cell on page */
  int nNew,                       /* Final number of cells on page */
  CellArray *pCArray              /* Array of cells and sizes */

){
  u8 * const aData = pPg->aData;
  const int hdr = pPg->hdrOffset;
  u8 *pBegin = &pPg->aCellIdx[nNew * 2];
  int nCell = pPg->nCell;       /* Cells stored on pPg */
  u8 *pData;
  u8 *pCellptr;
  int i;
  int iOldEnd = iOld + pPg->nCell + pPg->nOverflow;
  int iNewEnd = iNew + nNew;

#ifdef SQLITE_DEBUG
  u8 *pTmp = sqlite3PagerTempSpace(pPg->pBt->pPager);
  memcpy(pTmp, aData, pPg->pBt->usableSize);
#endif

  /* Remove cells from the start and end of the page */
  if( iOld<iNew ){
    int nShift = pageFreeArray(pPg, iOld, iNew-iOld, pCArray);


    memmove(pPg->aCellIdx, &pPg->aCellIdx[nShift*2], nCell*2);
    nCell -= nShift;
  }
  if( iNewEnd < iOldEnd ){
    nCell -= pageFreeArray(pPg, iNewEnd, iOldEnd - iNewEnd, pCArray);


  }

  pData = &aData[get2byteNotZero(&aData[hdr+5])];
  if( pData<pBegin ) goto editpage_fail;

  /* Add cells to the start of the page */
  if( iNew<iOld ){
    int nAdd = MIN(nNew,iOld-iNew);
    assert( (iOld-iNew)<nNew || nCell==0 || CORRUPT_DB );
    pCellptr = pPg->aCellIdx;
    memmove(&pCellptr[nAdd*2], pCellptr, nCell*2);
    if( pageInsertArray(
          pPg, pBegin, &pData, pCellptr,
          iNew, nAdd, pCArray
    ) ) goto editpage_fail;
    nCell += nAdd;
  }

  /* Add any overflow cells */
  for(i=0; i<pPg->nOverflow; i++){
    int iCell = (iOld + pPg->aiOvfl[i]) - iNew;
    if( iCell>=0 && iCell<nNew ){
      pCellptr = &pPg->aCellIdx[iCell * 2];
      memmove(&pCellptr[2], pCellptr, (nCell - iCell) * 2);
      nCell++;
      if( pageInsertArray(
            pPg, pBegin, &pData, pCellptr,
            iCell+iNew, 1, pCArray
      ) ) goto editpage_fail;
    }
  }

  /* Append cells to the end of the page */
  pCellptr = &pPg->aCellIdx[nCell*2];
  if( pageInsertArray(
        pPg, pBegin, &pData, pCellptr,
        iNew+nCell, nNew-nCell, pCArray
  ) ) goto editpage_fail;

  pPg->nCell = nNew;
  pPg->nOverflow = 0;

  put2byte(&aData[hdr+3], pPg->nCell);
  put2byte(&aData[hdr+5], pData - aData);

#ifdef SQLITE_DEBUG
  for(i=0; i<nNew && !CORRUPT_DB; i++){
    u8 *pCell = pCArray->apCell[i+iNew];
    int iOff = get2byte(&pPg->aCellIdx[i*2]);
    if( pCell>=aData && pCell<&aData[pPg->pBt->usableSize] ){
      pCell = &pTmp[pCell - aData];
    }
    assert( 0==memcmp(pCell, &aData[iOff],
            pCArray->pRef->xCellSize(pCArray->pRef, pCArray->apCell[i+iNew])) );
  }
#endif

  return SQLITE_OK;
 editpage_fail:
  /* Unable to edit this page. Rebuild it from scratch instead. */
  populateCellCache(pCArray, iNew, nNew);
  return rebuildPage(pPg, nNew, &pCArray->apCell[iNew], &pCArray->szCell[iNew]);
}

/*
** The following parameters determine how many adjacent pages get involved
** in a balancing operation.  NN is the number of neighbors on either side
** of the page that participate in the balancing operation.  NB is the
** total number of pages that participate, including the target page and

    u8 *pCell = pPage->apOvfl[0];
    u16 szCell = pPage->xCellSize(pPage, pCell);
    u8 *pStop;

    assert( sqlite3PagerIswriteable(pNew->pDbPage) );
    assert( pPage->aData[0]==(PTF_INTKEY|PTF_LEAFDATA|PTF_LEAF) );
    zeroPage(pNew, PTF_INTKEY|PTF_LEAFDATA|PTF_LEAF);
    rc = rebuildPage(pNew, 1, &pCell, &szCell);
    if( NEVER(rc) ) return rc;
    pNew->nFree = pBt->usableSize - pNew->cellOffset - 2 - szCell;

    /* If this is an auto-vacuum database, update the pointer map
    ** with entries for the new page, and any pointer from the 
    ** cell on the page to an overflow page. If either of these
    ** operations fails, the return code is set, but the contents
    ** of the parent page are still manipulated by thh code below.

  MemPage *pParent,               /* Parent page of siblings being balanced */
  int iParentIdx,                 /* Index of "the page" in pParent */
  u8 *aOvflSpace,                 /* page-size bytes of space for parent ovfl */
  int isRoot,                     /* True if pParent is a root-page */
  int bBulk                       /* True if this call is part of a bulk load */
){
  BtShared *pBt;               /* The whole database */

  int nMaxCells = 0;           /* Allocated size of apCell, szCell, aFrom. */
  int nNew = 0;                /* Number of pages in apNew[] */
  int nOld;                    /* Number of pages in apOld[] */
  int i, j, k;                 /* Loop counters */
  int nxDiv;                   /* Next divider slot in pParent->aCell[] */
  int rc = SQLITE_OK;          /* The return code */
  u16 leafCorrection;          /* 4 if pPage is a leaf.  0 if not */
  int leafData;                /* True if pPage is a leaf of a LEAFDATA tree */
  int usableSpace;             /* Bytes in pPage beyond the header */
  int pageFlags;               /* Value of pPage->aData[0] */

  int iSpace1 = 0;             /* First unused byte of aSpace1[] */
  int iOvflSpace = 0;          /* First unused byte of aOvflSpace[] */
  int szScratch;               /* Size of scratch memory requested */
  MemPage *apOld[NB];          /* pPage and up to two siblings */
  MemPage *apNew[NB+2];        /* pPage and up to NB siblings after balancing */
  u8 *pRight;                  /* Location in parent of right-sibling pointer */
  u8 *apDiv[NB-1];             /* Divider cells in pParent */
  int cntNew[NB+2];            /* Index in b.paCell[] of cell after i-th page */
  int cntOld[NB+2];            /* Old index in b.apCell[] */
  int szNew[NB+2];             /* Combined size of cells placed on i-th page */


  u8 *aSpace1;                 /* Space for copies of dividers cells */
  Pgno pgno;                   /* Temp var to store a page number in */
  u8 abDone[NB+2];             /* True after i'th new page is populated */
  Pgno aPgno[NB+2];            /* Page numbers of new pages before shuffling */
  Pgno aPgOrder[NB+2];         /* Copy of aPgno[] used for sorting pages */
  u16 aPgFlags[NB+2];          /* flags field of new pages before shuffling */
  CellArray b;                  /* Parsed information on cells being balanced */

  memset(abDone, 0, sizeof(abDone));
  b.nCell = 0;
  b.apCell = 0;
  pBt = pParent->pBt;
  assert( sqlite3_mutex_held(pBt->mutex) );
  assert( sqlite3PagerIswriteable(pParent->pDbPage) );

#if 0
  TRACE(("BALANCE: begin page %d child of %d\n", pPage->pgno, pParent->pgno));
#endif

  ** alignment */
  nMaxCells = (nMaxCells + 3)&~3;

  /*
  ** Allocate space for memory structures
  */
  szScratch =
       nMaxCells*sizeof(u8*)                       /* b.apCell */
     + nMaxCells*sizeof(u16)                       /* b.szCell */
     + pBt->pageSize;                              /* aSpace1 */

  /* EVIDENCE-OF: R-28375-38319 SQLite will never request a scratch buffer
  ** that is more than 6 times the database page size. */
  assert( szScratch<=6*(int)pBt->pageSize );
  b.apCell = sqlite3ScratchMalloc( szScratch ); 
  if( b.apCell==0 ){
    rc = SQLITE_NOMEM;
    goto balance_cleanup;
  }
  b.szCell = (u16*)&b.apCell[nMaxCells];
  aSpace1 = (u8*)&b.szCell[nMaxCells];
  assert( EIGHT_BYTE_ALIGNMENT(aSpace1) );

  /*
  ** Load pointers to all cells on sibling pages and the divider cells
  ** into the local b.apCell[] array.  Make copies of the divider cells
  ** into space obtained from aSpace1[]. The divider cells have already
  ** been removed from pParent.
  **
  ** If the siblings are on leaf pages, then the child pointers of the
  ** divider cells are stripped from the cells before they are copied
  ** into aSpace1[].  In this way, all cells in b.apCell[] are without
  ** child pointers.  If siblings are not leaves, then all cell in
  ** b.apCell[] include child pointers.  Either way, all cells in b.apCell[]
  ** are alike.
  **
  ** leafCorrection:  4 if pPage is a leaf.  0 if pPage is not a leaf.
  **       leafData:  1 if pPage holds key+data and pParent holds only keys.
  */
  b.pRef = apOld[0];
  leafCorrection = b.pRef->leaf*4;
  leafData = b.pRef->intKeyLeaf;
  for(i=0; i<nOld; i++){

    MemPage *pOld = apOld[i];
    int limit = pOld->nCell;
    u8 *aData = pOld->aData;
    u16 maskPage = pOld->maskPage;
    u8 *piCell = aData + pOld->cellOffset;
    u8 *piEnd;

    /* Verify that all sibling pages are of the same "type" (table-leaf,
    ** table-interior, index-leaf, or index-interior).
    */
    if( pOld->aData[0]!=apOld[0]->aData[0] ){
      rc = SQLITE_CORRUPT_BKPT;
      goto balance_cleanup;
    }

    /* Load b.apCell[] with pointers to all cells in pOld.  If pOld
    ** constains overflow cells, include them in the b.apCell[] array
    ** in the correct spot.
    **
    ** Note that when there are multiple overflow cells, it is always the
    ** case that they are sequential and adjacent.  This invariant arises
    ** because multiple overflows can only occurs when inserting divider
    ** cells into a parent on a prior balance, and divider cells are always
    ** adjacent and are inserted in order.  There is an assert() tagged
    ** with "NOTE 1" in the overflow cell insertion loop to prove this
    ** invariant.
    **
    ** This must be done in advance.  Once the balance starts, the cell
    ** offset section of the btree page will be overwritten and we will no
    ** long be able to find the cells if a pointer to each cell is not saved
    ** first.
    */
    memset(&b.szCell[b.nCell], 0, sizeof(b.szCell[0])*limit);
    if( pOld->nOverflow>0 ){
      memset(&b.szCell[b.nCell+limit], 0, sizeof(b.szCell[0])*pOld->nOverflow);
      limit = pOld->aiOvfl[0];
      for(j=0; j<limit; j++){
        b.apCell[b.nCell] = aData + (maskPage & get2byte(piCell));
        piCell += 2;
        b.nCell++;
      }
      for(k=0; k<pOld->nOverflow; k++){
        assert( k==0 || pOld->aiOvfl[k-1]+1==pOld->aiOvfl[k] );/* NOTE 1 */
        b.apCell[b.nCell] = pOld->apOvfl[k];
        b.nCell++;
      }



    }
    piEnd = aData + pOld->cellOffset + 2*pOld->nCell;

    while( piCell<piEnd ){
      assert( b.nCell<nMaxCells );
      b.apCell[b.nCell] = aData + (maskPage & get2byte(piCell));
      piCell += 2;
      b.nCell++;
    }

    cntOld[i] = b.nCell;
    if( i<nOld-1 && !leafData){
      u16 sz = (u16)szNew[i];
      u8 *pTemp;
      assert( b.nCell<nMaxCells );
      b.szCell[b.nCell] = sz;
      pTemp = &aSpace1[iSpace1];
      iSpace1 += sz;
      assert( sz<=pBt->maxLocal+23 );
      assert( iSpace1 <= (int)pBt->pageSize );
      memcpy(pTemp, apDiv[i], sz);
      b.apCell[b.nCell] = pTemp+leafCorrection;
      assert( leafCorrection==0 || leafCorrection==4 );
      b.szCell[b.nCell] = b.szCell[b.nCell] - leafCorrection;
      if( !pOld->leaf ){
        assert( leafCorrection==0 );
        assert( pOld->hdrOffset==0 );
        /* The right pointer of the child page pOld becomes the left
        ** pointer of the divider cell */
        memcpy(b.apCell[b.nCell], &pOld->aData[8], 4);
      }else{
        assert( leafCorrection==4 );
        while( b.szCell[b.nCell]<4 ){
          /* Do not allow any cells smaller than 4 bytes. If a smaller cell
          ** does exist, pad it with 0x00 bytes. */
          assert( b.szCell[b.nCell]==3 || CORRUPT_DB );
          assert( b.apCell[b.nCell]==&aSpace1[iSpace1-3] || CORRUPT_DB );
          aSpace1[iSpace1++] = 0x00;
          b.szCell[b.nCell]++;
        }
      }
      b.nCell++;
    }
  }

  /*
  ** Figure out the number of pages needed to hold all b.nCell cells.
  ** Store this number in "k".  Also compute szNew[] which is the total
  ** size of all cells on the i-th page and cntNew[] which is the index
  ** in b.apCell[] of the cell that divides page i from page i+1.  
  ** cntNew[k] should equal b.nCell.
  **
  ** Values computed by this block:
  **
  **           k: The total number of sibling pages
  **    szNew[i]: Spaced used on the i-th sibling page.
  **   cntNew[i]: Index in b.apCell[] and b.szCell[] for the first cell to
  **              the right of the i-th sibling page.
  ** usableSpace: Number of bytes of space available on each sibling.
  ** 
  */
  usableSpace = pBt->usableSize - 12 + leafCorrection;
  for(i=0; i<nOld; i++){
    MemPage *p = apOld[i];
    szNew[i] = usableSpace - p->nFree;
    if( szNew[i]<0 ){ rc = SQLITE_CORRUPT_BKPT; goto balance_cleanup; }
    for(j=0; j<p->nOverflow; j++){
      szNew[i] += 2 + p->xCellSize(p, p->apOvfl[j]);
    }
    cntNew[i] = cntOld[i];
  }
  k = nOld;
  for(i=0; i<k; i++){
    int sz;
    while( szNew[i]>usableSpace ){
      if( i+1>=k ){
        k = i+2;
        if( k>NB+2 ){ rc = SQLITE_CORRUPT_BKPT; goto balance_cleanup; }
        szNew[k-1] = 0;
        cntNew[k-1] = b.nCell;
      }
      sz = 2 + cachedCellSize(&b, cntNew[i]-1);
      szNew[i] -= sz;
      if( !leafData ){
        if( cntNew[i]<b.nCell ){
          sz = 2 + cachedCellSize(&b, cntNew[i]);
        }else{
          sz = 0;


        }
      }
      szNew[i+1] += sz;
      cntNew[i]--;
    }
    while( cntNew[i]<b.nCell ){
      sz = 2 + cachedCellSize(&b, cntNew[i]);
      if( szNew[i]+sz>usableSpace ) break;
      szNew[i] += sz;
      cntNew[i]++;
      if( !leafData ){
        if( cntNew[i]<b.nCell ){
          sz = 2 + cachedCellSize(&b, cntNew[i]);
        }else{
          sz = 0;
        }
      }
      szNew[i+1] -= sz;
    }
    if( cntNew[i]>=b.nCell ){
      k = i+1;
    }else if( cntNew[i] <= (i>0 ? cntNew[i-1] : 0) ){
      rc = SQLITE_CORRUPT_BKPT;
      goto balance_cleanup;
    }
  }

  /*
  ** The packing computed by the previous block is biased toward the siblings
  ** on the left side (siblings with smaller keys). The left siblings are
  ** always nearly full, while the right-most sibling might be nearly empty.
  ** The next block of code attempts to adjust the packing of siblings to
  ** get a better balance.
  **
  ** This adjustment is more than an optimization.  The packing above might
  ** be so out of balance as to be illegal.  For example, the right-most
  ** sibling might be completely empty.  This adjustment is not optional.
  */
  for(i=k-1; i>0; i--){
    int szRight = szNew[i];  /* Size of sibling on the right */
    int szLeft = szNew[i-1]; /* Size of sibling on the left */
    int r;              /* Index of right-most cell in left sibling */
    int d;              /* Index of first cell to the left of right sibling */

    r = cntNew[i-1] - 1;
    d = r + 1 - leafData;
    (void)cachedCellSize(&b, d);
    do{
      assert( d<nMaxCells );
      assert( r<nMaxCells );
      (void)cachedCellSize(&b, r);
      if( szRight!=0
       && (bBulk || szRight+b.szCell[d]+2 > szLeft-(b.szCell[r]+2)) ){

        break;
      }
      szRight += b.szCell[d] + 2;
      szLeft -= b.szCell[r] + 2;
      cntNew[i-1] = r;


      r--;
      d--;
    }while( r>=0 );
    szNew[i] = szRight;
    szNew[i-1] = szLeft;
    if( cntNew[i-1] <= (i>1 ? cntNew[i-2] : 0) ){
      rc = SQLITE_CORRUPT_BKPT;
      goto balance_cleanup;
    }
  }

  /* Sanity check:  For a non-corrupt database file one of the follwing
  ** must be true:
  **    (1) We found one or more cells (cntNew[0])>0), or
  **    (2) pPage is a virtual root page.  A virtual root page is when
  **        the real root page is page 1 and we are the only child of

    }else{
      assert( i>0 );
      rc = allocateBtreePage(pBt, &pNew, &pgno, (bBulk ? 1 : pgno), 0);
      if( rc ) goto balance_cleanup;
      zeroPage(pNew, pageFlags);
      apNew[i] = pNew;
      nNew++;
      cntOld[i] = b.nCell;

      /* Set the pointer-map entry for the new sibling page. */
      if( ISAUTOVACUUM ){
        ptrmapPut(pBt, pNew->pgno, PTRMAP_BTREE, pParent->pgno, &rc);
        if( rc!=SQLITE_OK ){
          goto balance_cleanup;
        }

    MemPage *pNew = apNew[0];
    u8 *aOld = pNew->aData;
    int cntOldNext = pNew->nCell + pNew->nOverflow;
    int usableSize = pBt->usableSize;
    int iNew = 0;
    int iOld = 0;

    for(i=0; i<b.nCell; i++){
      u8 *pCell = b.apCell[i];
      if( i==cntOldNext ){
        MemPage *pOld = (++iOld)<nNew ? apNew[iOld] : apOld[iOld];
        cntOldNext += pOld->nCell + pOld->nOverflow + !leafData;
        aOld = pOld->aData;
      }
      if( i==cntNew[iNew] ){
        pNew = apNew[++iNew];

       || pNew->pgno!=aPgno[iOld]
       || pCell<aOld
       || pCell>=&aOld[usableSize]
      ){
        if( !leafCorrection ){
          ptrmapPut(pBt, get4byte(pCell), PTRMAP_BTREE, pNew->pgno, &rc);
        }
        if( cachedCellSize(&b,i)>pNew->minLocal ){
          ptrmapPutOvflPtr(pNew, pCell, &rc);
        }
        if( rc ) goto balance_cleanup;
      }
    }
  }

  /* Insert new divider cells into pParent. */
  for(i=0; i<nNew-1; i++){
    u8 *pCell;
    u8 *pTemp;
    int sz;
    MemPage *pNew = apNew[i];
    j = cntNew[i];

    assert( j<nMaxCells );
    assert( b.apCell[j]!=0 );
    pCell = b.apCell[j];
    sz = b.szCell[j] + leafCorrection;
    pTemp = &aOvflSpace[iOvflSpace];
    if( !pNew->leaf ){
      memcpy(&pNew->aData[8], pCell, 4);
    }else if( leafData ){
      /* If the tree is a leaf-data tree, and the siblings are leaves, 
      ** then there is no divider cell in b.apCell[]. Instead, the divider 
      ** cell consists of the integer key for the right-most cell of 
      ** the sibling-page assembled above only.
      */
      CellInfo info;
      j--;
      pNew->xParseCell(pNew, b.apCell[j], &info);
      pCell = pTemp;
      sz = 4 + putVarint(&pCell[4], info.nKey);
      pTemp = 0;
    }else{
      pCell -= 4;
      /* Obscure case for non-leaf-data trees: If the cell at pCell was
      ** previously stored on a leaf node, and its reported size was 4
      ** bytes, then it may actually be smaller than this 
      ** (see btreeParseCellPtr(), 4 bytes is the minimum size of
      ** any cell). But it is important to pass the correct size to 
      ** insertCell(), so reparse the cell now.
      **
      ** Note that this can never happen in an SQLite data file, as all
      ** cells are at least 4 bytes. It only happens in b-trees used
      ** to evaluate "IN (SELECT ...)" and similar clauses.
      */
      if( b.szCell[j]==4 ){
        assert(leafCorrection==4);
        sz = pParent->xCellSize(pParent, pCell);
      }
    }
    iOvflSpace += sz;
    assert( sz<=pBt->maxLocal+23 );
    assert( iOvflSpace <= (int)pBt->pageSize );

      ** only after iPg+1 has already been updated. */
      assert( cntNew[iPg]>=cntOld[iPg] || abDone[iPg+1] );

      if( iPg==0 ){
        iNew = iOld = 0;
        nNewCell = cntNew[0];
      }else{
        iOld = iPg<nOld ? (cntOld[iPg-1] + !leafData) : b.nCell;
        iNew = cntNew[iPg-1] + !leafData;
        nNewCell = cntNew[iPg] - iNew;
      }

      rc = editPage(apNew[iPg], iOld, iNew, nNewCell, &b);
      if( rc ) goto balance_cleanup;
      abDone[iPg]++;
      apNew[iPg]->nFree = usableSpace-szNew[iPg];
      assert( apNew[iPg]->nOverflow==0 );
      assert( apNew[iPg]->nCell==nNewCell );
    }
  }

      u32 key = get4byte(&apNew[i]->aData[8]);
      ptrmapPut(pBt, key, PTRMAP_BTREE, apNew[i]->pgno, &rc);
    }
  }

  assert( pParent->isInit );
  TRACE(("BALANCE: finished: old=%d new=%d cells=%d\n",
          nOld, nNew, b.nCell));

  /* Free any old pages that were not reused as new pages.
  */
  for(i=nNew; i<nOld; i++){
    freePage(apOld[i], &rc);
  }

  }
#endif

  /*
  ** Cleanup before returning.
  */
balance_cleanup:
  sqlite3ScratchFree(b.apCell);
  for(i=0; i<nOld; i++){
    releasePage(apOld[i]);
  }
  for(i=0; i<nNew; i++){
    releasePage(apNew[i]);
  }

}

/* 
** Mark this cursor as an incremental blob cursor.
*/
void sqlite3BtreeIncrblobCursor(BtCursor *pCur){
  pCur->curFlags |= BTCF_Incrblob;
  pCur->pBtree->hasIncrblobCur = 1;
}
#endif

/*
** Set both the "read version" (single byte at byte offset 18) and 
** "write version" (single byte at byte offset 19) fields in the database
** header to iVersion.

*/
struct Btree {
  sqlite3 *db;       /* The database connection holding this btree */
  BtShared *pBt;     /* Sharable content of this btree */
  u8 inTrans;        /* TRANS_NONE, TRANS_READ or TRANS_WRITE */
  u8 sharable;       /* True if we can share pBt with another db */
  u8 locked;         /* True if db currently has pBt locked */
  u8 hasIncrblobCur; /* True if there are one or more Incrblob cursors */
  int wantToLock;    /* Number of nested calls to sqlite3BtreeEnter() */
  int nBackup;       /* Number of backup operations reading this btree */
  u32 iDataVersion;  /* Combines with pBt->pPager->iDataVersion */
  Btree *pNext;      /* List of other sharable Btrees from the same db */
  Btree *pPrev;      /* Back pointer of the same list */
#ifndef SQLITE_OMIT_SHARED_CACHE
  BtLock lock;       /* Object used to lock page 1 */

      assert( pTab && pExpr->pTab==pTab );
      if( pS ){
        /* The "table" is actually a sub-select or a view in the FROM clause
        ** of the SELECT statement. Return the declaration type and origin
        ** data for the result-set column of the sub-select.
        */
        if( iCol>=0 && ALWAYS(iCol<pS->pEList->nExpr) ){
          /* If iCol is less than zero, then the expression requests the
          ** rowid of the sub-select or view. This expression is legal (see 
          ** test case misc2.2.2) - it always evaluates to NULL.
          **
          ** The ALWAYS() is because iCol>=pS->pEList->nExpr will have been
          ** caught already by name resolution.
          */
          NameContext sNC;
          Expr *p = pS->pEList->a[iCol].pExpr;
          sNC.pSrcList = pS->pSrc;
          sNC.pNext = pNC;
          sNC.pParse = pNC->pParse;
          zType = columnType(&sNC, p,&zOrigDb,&zOrigTab,&zOrigCol, &estWidth); 

  CollSeq *pRet;
  if( p->pPrior ){
    pRet = multiSelectCollSeq(pParse, p->pPrior, iCol);
  }else{
    pRet = 0;
  }
  assert( iCol>=0 );
  /* iCol must be less than p->pEList->nExpr.  Otherwise an error would
  ** have been thrown during name resolution and we would not have gotten
  ** this far */
  if( pRet==0 && ALWAYS(iCol<p->pEList->nExpr) ){
    pRet = sqlite3ExprCollSeq(pParse, p->pEList->a[iCol].pExpr);
  }
  return pRet;
}

/*
** The select statement passed as the second parameter is a compound SELECT

  ** collation.
  */
  aPermute = sqlite3DbMallocRaw(db, sizeof(int)*nOrderBy);
  if( aPermute ){
    struct ExprList_item *pItem;
    for(i=0, pItem=pOrderBy->a; i<nOrderBy; i++, pItem++){
      assert( pItem->u.x.iOrderByCol>0 );
      assert( pItem->u.x.iOrderByCol<=p->pEList->nExpr );


      aPermute[i] = pItem->u.x.iOrderByCol - 1;
    }
    pKeyMerge = multiSelectOrderByKeyInfo(pParse, p, 1);
  }else{
    pKeyMerge = 0;
  }

    if( isAgg || (p->selFlags & SF_Distinct)!=0 || pSrc->nSrc!=1 ){
      return 0;
    }
    for(pSub1=pSub; pSub1; pSub1=pSub1->pPrior){
      testcase( (pSub1->selFlags & (SF_Distinct|SF_Aggregate))==SF_Distinct );
      testcase( (pSub1->selFlags & (SF_Distinct|SF_Aggregate))==SF_Aggregate );
      assert( pSub->pSrc!=0 );
      assert( pSub->pEList->nExpr==pSub1->pEList->nExpr );
      if( (pSub1->selFlags & (SF_Distinct|SF_Aggregate))!=0
       || (pSub1->pPrior && pSub1->op!=TK_ALL) 
       || pSub1->pSrc->nSrc<1

      ){
        return 0;
      }
      testcase( pSub1->pSrc->nSrc>1 );
    }

    /* Restriction 18. */

  assert( p->explain==0 );
  p->pResultSet = 0;
  db->busyHandler.nBusy = 0;
  if( db->u1.isInterrupted ) goto abort_due_to_interrupt;
  sqlite3VdbeIOTraceSql(p);
#ifndef SQLITE_OMIT_PROGRESS_CALLBACK
  if( db->xProgress ){
    u32 iPrior = p->aCounter[SQLITE_STMTSTATUS_VM_STEP];
    assert( 0 < db->nProgressOps );


    nProgressLimit = db->nProgressOps - (iPrior % db->nProgressOps);



  }
#endif
#ifdef SQLITE_DEBUG
  sqlite3BeginBenignMalloc();
  if( p->pc==0
   && (p->db->flags & (SQLITE_VdbeListing|SQLITE_VdbeEQP|SQLITE_VdbeTrace))!=0
  ){

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdarg.h>
#include <ctype.h>
#include "sqlite3.h"

#ifdef __unix__
# include <signal.h>
# include <unistd.h>
#endif

/*
** Files in the virtual file system.
*/
typedef struct VFile VFile;
struct VFile {
  char *zFilename;        /* Filename.  NULL for delete-on-close. From malloc() */
  int sz;                 /* Size of the file in bytes */

  va_start(ap, zFormat);
  vfprintf(stderr, zFormat, ap);
  va_end(ap);
  fprintf(stderr, "\n");
  exit(1);
}

/*
** Timeout handler
*/
#ifdef __unix__
static void timeoutHandler(int NotUsed){
  (void)NotUsed;
  fatalError("timeout\n");
}
#endif

/*
** Set the an alarm to go off after N seconds.  Disable the alarm
** if N==0
*/
static void setAlarm(int N){
#ifdef __unix__
  alarm(N);
#else
  (void)N;
#endif
}

#ifndef SQLITE_OMIT_PROGRESS_CALLBACK
/*
** This an SQL progress handler.  After an SQL statement has run for
** many steps, we want to interrupt it.  This guards against infinite
** loops from recursive common table expressions.
**
** *pVdbeLimitFlag is true if the --limit-vdbe command-line option is used.
** In that case, hitting the progress handler is a fatal error.
*/
static int progressHandler(void *pVdbeLimitFlag){
  if( *(int*)pVdbeLimitFlag ) fatalError("too many VDBE cycles");
  return 1;
}
#endif

/*
** Reallocate memory.  Show and error and quit if unable.
*/
static void *safe_realloc(void *pOld, int szNew){
  void *pNew = realloc(pOld, szNew);
  if( pNew==0 ) fatalError("unable to realloc for %d bytes", szNew);
  return pNew;

          }
        }
      }         
      sqlite3_finalize(pStmt);
    }
  }
}

/*
** Rebuild the database file.
**
**    (1)  Remove duplicate entries
**    (2)  Put all entries in order
**    (3)  Vacuum
*/
static void rebuild_database(sqlite3 *db){
  int rc;
  rc = sqlite3_exec(db, 
     "BEGIN;\n"
     "CREATE TEMP TABLE dbx AS SELECT DISTINCT dbcontent FROM db;\n"
     "DELETE FROM db;\n"
     "INSERT INTO db(dbid, dbcontent) SELECT NULL, dbcontent FROM dbx ORDER BY 2;\n"
     "DROP TABLE dbx;\n"
     "CREATE TEMP TABLE sx AS SELECT DISTINCT sqltext FROM xsql;\n"
     "DELETE FROM xsql;\n"
     "INSERT INTO xsql(sqlid,sqltext) SELECT NULL, sqltext FROM sx ORDER BY 2;\n"
     "DROP TABLE sx;\n"
     "COMMIT;\n"
     "PRAGMA page_size=1024;\n"
     "VACUUM;\n", 0, 0, 0);
  if( rc ) fatalError("cannot rebuild: %s", sqlite3_errmsg(db));
}

/*
** Print sketchy documentation for this utility program
*/
static void showHelp(void){
  printf("Usage: %s [options] SOURCE-DB ?ARGS...?\n", g.zArgv0);
  printf(
"Read databases and SQL scripts from SOURCE-DB and execute each script against\n"
"each database, checking for crashes and memory leaks.\n"
"Options:\n"
"  --cell-size-check     Set the PRAGMA cell_size_check=ON\n"
"  --dbid N              Use only the database where dbid=N\n"
"  --help                Show this help text\n"
"  -q                    Reduced output\n"
"  --quiet               Reduced output\n"
"  --limit-vdbe          Panic if an sync SQL runs for more than 100,000 cycles\n"
"  --load-sql ARGS...    Load SQL scripts fro files into SOURCE-DB\n"
"  --load-db ARGS...     Load template databases from files into SOURCE_DB\n"
"  -m TEXT               Add a description to the database\n"
"  --native-vfs          Use the native VFS for initially empty database files\n"
"  --rebuild             Rebuild and vacuum the database file\n"
"  --result-trace        Show the results of each SQL command\n"
"  --sqlid N             Use only SQL where sqlid=N\n"
"  --timeline N          Abort if any single test case needs more than N seconds\n"
"  -v                    Increased output\n"
"  --verbose             Increased output\n"
  );
}

int main(int argc, char **argv){
  sqlite3_int64 iBegin;        /* Start time of this program */
  int quietFlag = 0;           /* True if --quiet or -q */
  int verboseFlag = 0;         /* True if --verbose or -v */
  char *zInsSql = 0;           /* SQL statement for --load-db or --load-sql */
  int iFirstInsArg = 0;        /* First argv[] to use for --load-db or --load-sql */
  sqlite3 *db = 0;             /* The open database connection */
  sqlite3_stmt *pStmt;         /* A prepared statement */
  int rc;                      /* Result code from SQLite interface calls */
  Blob *pSql;                  /* For looping over SQL scripts */
  Blob *pDb;                   /* For looping over template databases */
  int i;                       /* Loop index for the argv[] loop */
  int onlySqlid = -1;          /* --sqlid */
  int onlyDbid = -1;           /* --dbid */
  int nativeFlag = 0;          /* --native-vfs */
  int rebuildFlag = 0;         /* --rebuild */
  int vdbeLimitFlag = 0;       /* --limit-vdbe */
  int timeoutTest = 0;         /* undocumented --timeout-test flag */
  int runFlags = 0;            /* Flags sent to runSql() */
  char *zMsg = 0;              /* Add this message */
  int nSrcDb = 0;              /* Number of source databases */
  char **azSrcDb = 0;          /* Array of source database names */
  int iSrcDb;                  /* Loop over all source databases */
  int nTest = 0;               /* Total number of tests performed */
  char *zDbName = "";          /* Appreviated name of a source database */
  const char *zFailCode = 0;   /* Value of the TEST_FAILURE environment variable */
  int cellSzCkFlag = 0;        /* --cell-size-check */
  int sqlFuzz = 0;             /* True for SQL fuzz testing. False for DB fuzz */
  int iTimeout = 120;          /* Default 120-second timeout */

  iBegin = timeOfDay();
#ifdef __unix__
  signal(SIGALRM, timeoutHandler);
#endif
  g.zArgv0 = argv[0];
  zFailCode = getenv("TEST_FAILURE");
  for(i=1; i<argc; i++){
    const char *z = argv[i];
    if( z[0]=='-' ){
      z++;
      if( z[0]=='-' ) z++;
      if( strcmp(z,"cell-size-check")==0 ){
        cellSzCkFlag = 1;
      }else
      if( strcmp(z,"dbid")==0 ){
        if( i>=argc-1 ) fatalError("missing arguments on %s", argv[i]);
        onlyDbid = atoi(argv[++i]);
      }else
      if( strcmp(z,"help")==0 ){
        showHelp();
        return 0;
      }else
      if( strcmp(z,"limit-vdbe")==0 ){
        vdbeLimitFlag = 1;
      }else
      if( strcmp(z,"load-sql")==0 ){
        zInsSql = "INSERT INTO xsql(sqltext) VALUES(CAST(readfile(?1) AS text))";
        iFirstInsArg = i+1;
        break;
      }else
      if( strcmp(z,"load-db")==0 ){

      }else
      if( strcmp(z,"native-vfs")==0 ){
        nativeFlag = 1;
      }else
      if( strcmp(z,"quiet")==0 || strcmp(z,"q")==0 ){
        quietFlag = 1;
        verboseFlag = 0;
      }else
      if( strcmp(z,"rebuild")==0 ){
        rebuildFlag = 1;
      }else
      if( strcmp(z,"result-trace")==0 ){
        runFlags |= SQL_OUTPUT;
      }else
      if( strcmp(z,"sqlid")==0 ){
        if( i>=argc-1 ) fatalError("missing arguments on %s", argv[i]);
        onlySqlid = atoi(argv[++i]);
      }else
      if( strcmp(z,"timeout")==0 ){
        if( i>=argc-1 ) fatalError("missing arguments on %s", argv[i]);
        iTimeout = atoi(argv[++i]);
      }else
      if( strcmp(z,"timeout-test")==0 ){
        timeoutTest = 1;
#ifndef __unix__
        fatalError("timeout is not available on non-unix systems");
#endif
      }else
      if( strcmp(z,"verbose")==0 || strcmp(z,"v")==0 ){
        quietFlag = 0;
        verboseFlag = 1;
        runFlags |= SQL_TRACE;
      }else
      {

  /* Process each source database separately */
  for(iSrcDb=0; iSrcDb<nSrcDb; iSrcDb++){
    rc = sqlite3_open(azSrcDb[iSrcDb], &db);
    if( rc ){
      fatalError("cannot open source database %s - %s",
      azSrcDb[iSrcDb], sqlite3_errmsg(db));
    }
    rc = sqlite3_exec(db,
       "CREATE TABLE IF NOT EXISTS db(\n"
       "  dbid INTEGER PRIMARY KEY, -- database id\n"
       "  dbcontent BLOB            -- database disk file image\n"
       ");\n"
       "CREATE TABLE IF NOT EXISTS xsql(\n"
       "  sqlid INTEGER PRIMARY KEY,   -- SQL script id\n"
       "  sqltext TEXT                 -- Text of SQL statements to run\n"

        sqlite3_step(pStmt);
        rc = sqlite3_reset(pStmt);
        if( rc ) fatalError("insert failed for %s", argv[i]);
      }
      sqlite3_finalize(pStmt);
      rc = sqlite3_exec(db, "COMMIT", 0, 0, 0);
      if( rc ) fatalError("cannot commit the transaction: %s", sqlite3_errmsg(db));
      rebuild_database(db);
      sqlite3_close(db);
      return 0;
    }
  
    /* Load all SQL script content and all initial database images from the
    ** source db
    */
    blobListLoadFromDb(db, "SELECT sqlid, sqltext FROM xsql", onlySqlid,
                           &g.nSql, &g.pFirstSql);
    if( g.nSql==0 ) fatalError("need at least one SQL script");
    blobListLoadFromDb(db, "SELECT dbid, dbcontent FROM db", onlyDbid,
                       &g.nDb, &g.pFirstDb);
    if( g.nDb==0 ){
      g.pFirstDb = safe_realloc(0, sizeof(Blob));
      memset(g.pFirstDb, 0, sizeof(Blob));
      g.pFirstDb->id = 1;
      g.pFirstDb->seq = 0;
      g.nDb = 1;
      sqlFuzz = 1;
    }
  
    /* Print the description, if there is one */
    if( !quietFlag ){
      int i;
      zDbName = azSrcDb[iSrcDb];
      i = strlen(zDbName) - 1;
      while( i>0 && zDbName[i-1]!='/' && zDbName[i-1]!='\\' ){ i--; }
      zDbName += i;
      sqlite3_prepare_v2(db, "SELECT msg FROM readme", -1, &pStmt, 0);
      if( pStmt && sqlite3_step(pStmt)==SQLITE_ROW ){
        printf("%s: %s\n", zDbName, sqlite3_column_text(pStmt,0));
      }
      sqlite3_finalize(pStmt);
    }

    /* Rebuild the database, if requested */
    if( rebuildFlag ){
      if( !quietFlag ){
        printf("%s: rebuilding... ", zDbName);
        fflush(stdout);
      }
      rebuild_database(db);
      if( !quietFlag ) printf("done\n");
    }
  
    /* Close the source database.  Verify that no SQLite memory allocations are
    ** outstanding.
    */
    sqlite3_close(db);
    if( sqlite3_memory_used()>0 ){
      fatalError("SQLite has memory in use before the start of testing");

        if( nativeFlag && pDb->sz==0 ){
          openFlags |= SQLITE_OPEN_MEMORY;
          zVfs = 0;
        }
        rc = sqlite3_open_v2("main.db", &db, openFlags, zVfs);
        if( rc ) fatalError("cannot open inmem database");
        if( cellSzCkFlag ) runSql(db, "PRAGMA cell_size_check=ON", runFlags);
        setAlarm(iTimeout);
#ifndef SQLITE_OMIT_PROGRESS_CALLBACK
        if( sqlFuzz || vdbeLimitFlag ){
          sqlite3_progress_handler(db, 100000, progressHandler, &vdbeLimitFlag);
        }
#endif
        do{
          runSql(db, (char*)pSql->a, runFlags);
        }while( timeoutTest );
        setAlarm(0);
        sqlite3_close(db);
        if( sqlite3_memory_used()>0 ) fatalError("memory leak");
        reformatVfs();
        nTest++;
        g.zTestName[0] = 0;

        /* Simulate an error if the TEST_FAILURE environment variable is "5".

    SELECT * FROM abc;
  }
  execsql {
    SELECT * FROM sqlite_master;
    BEGIN;
    SELECT * FROM def;
  } db2
  value_in_range [expr $::pgalloc*2] 0.99 [sqlite3_release_memory]
} [value_in_range [expr $::pgalloc * 2] 0.99]
do_test malloc5-3.2 {
  concat \
    [execsql {SELECT * FROM abc; COMMIT}] \
    [execsql {SELECT * FROM def; COMMIT} db2]
} {1 2 3 4 5 6 7 8 9 10 11 12}

db2 close

  do_tracesql_test 6.2.3 {
    SELECT word, distance FROM t3 WHERE rowid = 10 AND word MATCH 'kiiner';
  } {keener 300
    {SELECT id, word, rank, k1  FROM "main"."t3_vocab" WHERE langid=0 AND k2>=?1 AND k2<?2}
  }
}

#------------------------------------------------------------------------- 
# Test that the spellfix1 table supports conflict handling (OR REPLACE 
# and so on).
#
do_execsql_test 7.1 {
  CREATE VIRTUAL TABLE t4 USING spellfix1;
  PRAGMA table_info = t4;
} {
  0 word {} 0 {} 0 
  1 rank {} 0 {} 0 
  2 distance {} 0 {} 0 
  3 langid {} 0 {} 0 
  4 score {} 0 {} 0 
  5 matchlen {} 0 {} 0
}

do_execsql_test 7.2.1 {
  INSERT INTO t4(rowid, word) VALUES(1, 'Archilles');
  INSERT INTO t4(rowid, word) VALUES(2, 'Pluto');
  INSERT INTO t4(rowid, word) VALUES(3, 'Atrides');
  INSERT OR REPLACE INTO t4(rowid, word) VALUES(2, 'Apollo');
  SELECT rowid, word FROM t4;
} {
  1 Archilles   2 Apollo   3 Atrides
}
do_catchsql_test 7.2.2 {
  INSERT OR ABORT INTO t4(rowid, word) VALUES(1, 'Leto');
} {1 {constraint failed}}
do_catchsql_test 7.2.3 {
  INSERT OR ROLLBACK INTO t4(rowid, word) VALUES(3, 'Zeus');
} {1 {constraint failed}}
do_catchsql_test 7.2.4 {
  INSERT OR FAIL INTO t4(rowid, word) VALUES(3, 'Zeus');
} {1 {constraint failed}}
do_execsql_test 7.2.5 {
  INSERT OR IGNORE INTO t4(rowid, word) VALUES(3, 'Zeus');
  SELECT rowid, word FROM t4;
} {
  1 Archilles   2 Apollo   3 Atrides
}

do_execsql_test 7.3.1 {
  UPDATE OR REPLACE t4 SET rowid=3 WHERE rowid=1;
  SELECT rowid, word FROM t4;
} {2 Apollo 3 Archilles}
do_catchsql_test 7.3.2 {
  UPDATE OR ABORT t4 SET rowid=3 WHERE rowid=2;
} {1 {constraint failed}}
do_catchsql_test 7.3.3 {
  UPDATE OR ROLLBACK t4 SET rowid=3 WHERE rowid=2;
} {1 {constraint failed}}
do_catchsql_test 7.3.4 {
  UPDATE OR FAIL t4 SET rowid=3 WHERE rowid=2;
} {1 {constraint failed}}
do_execsql_test 7.3.5 {
  UPDATE OR IGNORE t4 SET rowid=3 WHERE rowid=2;
  SELECT rowid, word FROM t4;
} {2 Apollo  3 Archilles}

do_execsql_test 7.4.1 {
  DELETE FROM t4;
  INSERT INTO t4(rowid, word) VALUES(10, 'Agamemnon');
  INSERT INTO t4(rowid, word) VALUES(20, 'Patroclus');
  INSERT INTO t4(rowid, word) VALUES(30, 'Chryses');

  CREATE TABLE t5(i, w);
  INSERT INTO t5 VALUES(5,  'Poseidon');
  INSERT INTO t5 VALUES(20, 'Chronos');
  INSERT INTO t5 VALUES(30, 'Hera');
}

db_save_and_close
foreach {tn conflict err bRollback res} {
  0 ""            {1 {constraint failed}} 0
                  {10 Agamemnon 20 Patroclus 30 Chryses}
  1 "OR REPLACE"  {0 {}} 0
                  {5 Poseidon 10 Agamemnon 20 Chronos 30 Hera}
  2 "OR ABORT"    {1 {constraint failed}} 0
                  {10 Agamemnon 20 Patroclus 30 Chryses}
  3 "OR ROLLBACK" {1 {constraint failed}} 1
                  {10 Agamemnon 20 Patroclus 30 Chryses}
  5 "OR IGNORE"   {0 {}} 0
                  {5 Poseidon 10 Agamemnon 20 Patroclus 30 Chryses}
} {
  db_restore_and_reopen
  load_static_extension db spellfix nextchar

  execsql BEGIN
  set sql "INSERT $conflict INTO t4(rowid, word) SELECT i, w FROM t5"
  do_catchsql_test 7.4.2.$tn.1 $sql $err
  do_execsql_test 7.4.2.$tn.2 { SELECT rowid, word FROM t4 } $res

  do_test 7.4.2.$tn.3 { sqlite3_get_autocommit db } $bRollback
  catchsql ROLLBACK
}

foreach {tn conflict err bRollback res} {
  0 ""            {1 {constraint failed}} 0
                  {10 Agamemnon 20 Patroclus 30 Chryses}
  1 "OR REPLACE"  {0 {}} 0
                  {15 Agamemnon 45 Chryses}
  2 "OR ABORT"    {1 {constraint failed}} 0
                  {10 Agamemnon 20 Patroclus 30 Chryses}
  3 "OR ROLLBACK" {1 {constraint failed}} 1
                  {10 Agamemnon 20 Patroclus 30 Chryses}
  5 "OR IGNORE"   {0 {}} 0
                  {15 Agamemnon 20 Patroclus 45 Chryses}
} {
  db_restore_and_reopen
  load_static_extension db spellfix nextchar

  execsql BEGIN
  set sql "UPDATE $conflict t4 SET rowid=rowid + (rowid/2)"
  do_catchsql_test 7.5.2.$tn.1 $sql $err
  do_execsql_test 7.5.2.$tn.2 { SELECT rowid, word FROM t4 } $res
  do_test 7.5.2.$tn.3 { sqlite3_get_autocommit db } $bRollback
  catchsql ROLLBACK
}

finish_test