if( pCur->pKeyInfo==0 ){
    assert( pX->pKey==0 );
    /* If this is an insert into a table b-tree, invalidate any incrblob 
    ** cursors open on the row being replaced */
    invalidateIncrblobCursors(p, pCur->pgnoRoot, pX->nKey, 0);

    /* If BTREE_SAVEPOSITION is set, the cursor must already be pointing 
    ** to a row with the same key as the new entry being inserted.  */


    assert( (flags & BTREE_SAVEPOSITION)==0 || 

            ((pCur->curFlags&BTCF_ValidNKey)!=0 && pX->nKey==pCur->info.nKey) );



    /* If the cursor is currently on the last row and we are appending a
    ** new row onto the end, set the "loc" to avoid an unnecessary
    ** btreeMoveto() call */






    if( (pCur->curFlags&BTCF_ValidNKey)!=0 && pX->nKey==pCur->info.nKey ){
      /* The current is currently pointing to the entry that is to be
      ** overwritten */
      assert( pX->nData>=0 && pX->nZero>=0 );
      if( pCur->info.nSize!=0
       && pCur->info.nPayload==(u32)pX->nData+pX->nZero
      ){

        return btreeOverwriteCell(pCur, pX);
      }
      loc = 0;

    }else if( loc==0 ){




      rc = sqlite3BtreeMovetoUnpacked(pCur, 0, pX->nKey, flags!=0, &loc);
      if( rc ) return rc;
    }













  }else if( loc==0 && (flags & BTREE_SAVEPOSITION)==0 ){
    if( pX->nMem ){
      UnpackedRecord r;
      r.pKeyInfo = pCur->pKeyInfo;
      r.aMem = pX->aMem;
      r.nField = pX->nMem;
      r.default_rc = 0;
      r.errCode = 0;
      r.r1 = 0;
      r.r2 = 0;
      r.eqSeen = 0;
      rc = sqlite3BtreeMovetoUnpacked(pCur, &r, 0, flags!=0, &loc);
    }else{
      rc = btreeMoveto(pCur, pX->pKey, pX->nKey, flags!=0, &loc);
    }
    if( rc ) return rc;

  }
  assert( pCur->eState==CURSOR_VALID || (pCur->eState==CURSOR_INVALID && loc) );

  pPage = pCur->pPage;
  assert( pPage->intKey || pX->nKey>=0 );
  assert( pPage->leaf || !pPage->intKey );

  if( pCur->pKeyInfo==0 ){
    assert( pX->pKey==0 );
    /* If this is an insert into a table b-tree, invalidate any incrblob 
    ** cursors open on the row being replaced */
    invalidateIncrblobCursors(p, pCur->pgnoRoot, pX->nKey, 0);

    /* If BTREE_SAVEPOSITION is set, the cursor must already be pointing 
    ** to a row with the same key as the new entry being inserted.
    */
#ifdef SQLITE_DEBUG
    if( flags & BTREE_SAVEPOSITION ){
      assert( pCur->curFlags & BTCF_ValidNKey );
      assert( pX->nKey==pCur->info.nKey );
      assert( pCur->info.nSize!=0 );
      assert( loc==0 );
    }



#endif

    /* On the other hand, BTREE_SAVEPOSITION==0 does not imply
    ** that the cursor is not pointing to a row to be overwritten.
    ** So do a complete check.
    */
    if( (pCur->curFlags&BTCF_ValidNKey)!=0 && pX->nKey==pCur->info.nKey ){
      /* The cursor is pointing to the entry that is to be
      ** overwritten */
      assert( pX->nData>=0 && pX->nZero>=0 );
      if( pCur->info.nSize!=0
       && pCur->info.nPayload==(u32)pX->nData+pX->nZero
      ){
        /* New entry is the same size as the old.  Do an overwrite */
        return btreeOverwriteCell(pCur, pX);
      }

      assert( loc==0 );
    }else if( loc==0 ){
      /* The cursor is *not* pointing to the cell to be overwritten, nor
      ** to an adjacent cell.  Move the cursor so that it is pointing either
      ** to the cell to be overwritten or an adjacent cell.
      */
      rc = sqlite3BtreeMovetoUnpacked(pCur, 0, pX->nKey, flags!=0, &loc);
      if( rc ) return rc;
    }
  }else{
    /* This is an index or a WITHOUT ROWID table */

    /* If BTREE_SAVEPOSITION is set, the cursor must already be pointing 
    ** to a row with the same key as the new entry being inserted.
    */
    assert( (flags & BTREE_SAVEPOSITION)==0 || loc==0 );

    /* If the cursor is not already pointing either to the cell to be
    ** overwritten, or if a new cell is being inserted, if the cursor is
    ** not pointing to an immediately adjacent cell, then move the cursor
    ** so that it does.
    */
    if( loc==0 && (flags & BTREE_SAVEPOSITION)==0 ){
      if( pX->nMem ){
        UnpackedRecord r;
        r.pKeyInfo = pCur->pKeyInfo;
        r.aMem = pX->aMem;
        r.nField = pX->nMem;
        r.default_rc = 0;
        r.errCode = 0;
        r.r1 = 0;
        r.r2 = 0;
        r.eqSeen = 0;
        rc = sqlite3BtreeMovetoUnpacked(pCur, &r, 0, flags!=0, &loc);
      }else{
        rc = btreeMoveto(pCur, pX->pKey, pX->nKey, flags!=0, &loc);
      }
      if( rc ) return rc;
    }
  }
  assert( pCur->eState==CURSOR_VALID || (pCur->eState==CURSOR_INVALID && loc) );

  pPage = pCur->pPage;
  assert( pPage->intKey || pX->nKey>=0 );
  assert( pPage->leaf || !pPage->intKey );