SQLite

  fts5BufferZero(&pPage->buf);
  fts5BufferAppendBlob(&p->rc, &pPage->buf, 4, zero);
  pPage->pgno++;

  /* Increase the leaves written counter */
  pWriter->nLeafWritten++;

  /* The new leaf holds no terms or rowids */
  pWriter->bFirstTermInPage = 1;
  pWriter->bFirstRowidInPage = 1;
}

/*
** Append term pTerm/nTerm to the segment being written by the writer passed
** as the second argument.
**
** If an error occurs, set the Fts5Index.rc error code. If an error has 

  pWriter->bFirstRowidInPage = 0;
  pWriter->bFirstRowidInDoclist = 1;

  /* If the current leaf page is full, flush it to disk. */
  if( pPage->buf.n>=p->pConfig->pgsz ){
    fts5WriteFlushLeaf(p, pWriter);

  }
}

/*
** Append a docid and position-list size field to the writers output. 
*/
static void fts5WriteAppendRowid(

    pWriter->bFirstRowidInDoclist = 0;
    pWriter->bFirstRowidInPage = 0;

    fts5BufferAppendVarint(&p->rc, &pPage->buf, nPos);

    if( pPage->buf.n>=p->pConfig->pgsz ){
      fts5WriteFlushLeaf(p, pWriter);

    }
  }
}

static void fts5WriteAppendPoslistInt(
  Fts5Index *p, 
  Fts5SegWriter *pWriter,
  int iVal
){
  if( p->rc==SQLITE_OK ){
    Fts5PageWriter *pPage = &pWriter->aWriter[0];
    fts5BufferAppendVarint(&p->rc, &pPage->buf, iVal);
    if( pPage->buf.n>=p->pConfig->pgsz ){
      fts5WriteFlushLeaf(p, pWriter);

    }
  }
}

static void fts5WriteAppendPoslistData(
  Fts5Index *p, 
  Fts5SegWriter *pWriter, 

      i64 dummy;
      nCopy += getVarint(&a[nCopy], (u64*)&dummy);
    }
    fts5BufferAppendBlob(&p->rc, &pPage->buf, nCopy, a);
    a += nCopy;
    n -= nCopy;
    fts5WriteFlushLeaf(p, pWriter);

  }
  if( n>0 ){
    fts5BufferAppendBlob(&p->rc, &pPage->buf, n, a);
  }
}

static void fts5WriteAppendZerobyte(Fts5Index *p, Fts5SegWriter *pWriter){

      if( pgsz>=(pBuf->n + nDoclist + 1) ){
        /* The entire doclist will fit on the current leaf. */
        fts5BufferSafeAppendBlob(pBuf, pDoclist, nDoclist);
      }else{
        i64 iRowid = 0;
        i64 iDelta = 0;
        int iOff = 0;

        writer.bFirstRowidInPage = 0;

        /* The entire doclist will not fit on this leaf. The following 
        ** loop iterates through the poslists that make up the current 
        ** doclist.  */
        while( iOff<nDoclist ){
          int nPos;
          int nCopy;
          int bDummy;
          iOff += getVarint(&pDoclist[iOff], (u64*)&iDelta);
          nCopy = fts5GetPoslistSize(&pDoclist[iOff], &nPos, &bDummy);
          nCopy += nPos;
          iRowid += iDelta;
          
          if( writer.bFirstRowidInPage ){
            fts5PutU16(&pBuf->p[0], pBuf->n);   /* first docid on page */
            pBuf->n += sqlite3PutVarint(&pBuf->p[pBuf->n], iRowid);
            writer.bFirstRowidInPage = 0;
            fts5WriteDlidxAppend(p, &writer, iRowid);
          }else{
            pBuf->n += sqlite3PutVarint(&pBuf->p[pBuf->n], iDelta);
          }
          assert( pBuf->n<=pBuf->nSpace );

          if( (pBuf->n + nCopy) <= pgsz ){

            while( 1 ){
              int nSpace = pgsz - pBuf->n;
              int n = 0;
              if( (nCopy - iPos)<=nSpace ){
                n = nCopy - iPos;
              }else{
                n = fts5PoslistPrefix(&pPoslist[iPos], nSpace);

              }
              assert( n>0 );
              fts5BufferSafeAppendBlob(pBuf, &pPoslist[iPos], n);
              iPos += n;
              if( pBuf->n>=pgsz ){
                fts5WriteFlushLeaf(p, &writer);
                pBuf = &writer.aWriter[0].buf;
              }
              if( iPos>=nCopy ) break;
            }

          }
          iOff += nCopy;
        }
      }

      pBuf->p[pBuf->n++] = '\0';
      assert( pBuf->n<=pBuf->nSpace );

}

do_execsql_test 1.0 { 
  CREATE VIRTUAL TABLE t1 USING fts5(x);
  INSERT INTO t1(t1, rank) VALUES('pgsz', 32);
}

# This test populates the FTS5 table containing $nEntry entries. Rows are 
# numbered from 0 to ($nEntry-1). The rowid for row $i is:
#
#   ($iFirst + $i*$nStep)
#
# Each document is of the form "a b c a b c a b c...". If the row number ($i)
# is an integer multiple of $spc1, then an "x" token is appended to the
# document. If it is *also* a multiple of $spc2, a "y" token is also appended.
#
proc do_dlidx_test1 {tn spc1 spc2 nEntry iFirst nStep} {



  do_execsql_test $tn.0 { DELETE FROM t1 }

  set xdoc [list]
  set ydoc [list]

  execsql BEGIN
  for {set i 0} {$i < $nEntry} {incr i} {
    set rowid [expr $i * $nStep]
    set doc [string trim [string repeat "a b c " 100]]
    if {($i % $spc1)==0} {
      lappend xdoc $rowid
      append doc " x" 
      if {($i % $spc2)==0} { 
        lappend ydoc $rowid
        append doc " y" 
      }
    }
    execsql { INSERT INTO t1(rowid, x) VALUES($rowid, $doc) }
  }
  execsql COMMIT

  do_test $tn.1 {
    execsql { INSERT INTO t1(t1) VALUES('integrity-check') }
  } {}
  


  do_fb_test $tn.3.1 { SELECT rowid FROM t1 WHERE t1 MATCH 'a AND x' } $xdoc
  do_fb_test $tn.3.2 { SELECT rowid FROM t1 WHERE t1 MATCH 'x AND a' } $xdoc
  
  do_fb_test $tn.4.1 { SELECT rowid FROM t1 WHERE t1 MATCH 'a AND y' } $ydoc
  do_fb_test $tn.4.2 { SELECT rowid FROM t1 WHERE t1 MATCH 'y AND a' } $ydoc
  
  do_fb_test $tn.5.1 { 
    SELECT rowid FROM t1 WHERE t1 MATCH 'a + b + c + x' } $xdoc
  do_fb_test $tn.5.2 { 
    SELECT rowid FROM t1 WHERE t1 MATCH 'b + c + x + y' } $ydoc
}


do_dlidx_test1 1.1     10 100 10000 0 1000
do_dlidx_test1 1.2     10 10  10000 0 128
do_dlidx_test1 1.3     10 10  100   0 36028797018963970
do_dlidx_test1 1.3     10 10  50    0 150000000000000000



finish_test