SQLite

    }
  }

  *pnRight = p - aOut;
}

/*
** Argument pList points to a position list nList bytes in size. This
** function checks to see if the position list contains any entries for
** a token in position 0 (of any column). If so, it writes argument iDelta
** to the output buffer pOut, followed by a position list consisting only
** of the entries from pList at position 0, and terminated by an 0x00 byte.
** The value returned is the number of bytes written to pOut (if any).



*/
int sqlite3Fts3FirstFilter(
  sqlite3_int64 iDelta,           /* Varint that may be written to pOut */
  char *pList,                    /* Position list (no 0x00 term) */
  int nList,                      /* Size of pList in bytes */
  char *pOut                      /* Write output here */
){
  int nOut = 0;
  int bWritten = 0;               /* True once iDelta has been written */
  char *p = pList;

  char *pEnd = &pList[nList];








  if( *p!=0x01 ){
    if( *p==0x02 ){
      nOut += sqlite3Fts3PutVarint(&pOut[nOut], iDelta);
      pOut[nOut++] = 0x02;
      bWritten = 1;
    }
    fts3ColumnlistCopy(0, &p);
  }

  while( p<pEnd && *p==0x01 ){
    sqlite3_int64 iCol;
    p++;
    p += sqlite3Fts3GetVarint(p, &iCol);
    if( *p==0x02 ){
      if( bWritten==0 ){
        nOut += sqlite3Fts3PutVarint(&pOut[nOut], iDelta);
        bWritten = 1;
      }
      pOut[nOut++] = 0x01;
      nOut += sqlite3Fts3PutVarint(&pOut[nOut], iCol);
      pOut[nOut++] = 0x02;
    }
    fts3ColumnlistCopy(0, &p);
  }
  if( bWritten ){
    pOut[nOut++] = 0x00;
  }





  return nOut;

}


/*
** Merge all doclists in the TermSelect.aaOutput[] array into a single
** doclist stored in TermSelect.aaOutput[0]. If successful, delete all
** other doclists (except the aaOutput[0] one) and return SQLITE_OK.

  Fts3SegFilter filter;           /* Segment term filter configuration */

  pSegcsr = pTok->pSegcsr;
  memset(&tsc, 0, sizeof(TermSelect));

  filter.flags = FTS3_SEGMENT_IGNORE_EMPTY | FTS3_SEGMENT_REQUIRE_POS
        | (pTok->isPrefix ? FTS3_SEGMENT_PREFIX : 0)
        | (pTok->bFirst ? FTS3_SEGMENT_FIRST : 0)
        | (iColumn<p->nColumn ? FTS3_SEGMENT_COLUMN_FILTER : 0);
  filter.iCol = iColumn;
  filter.zTerm = pTok->z;
  filter.nTerm = pTok->n;

  rc = sqlite3Fts3SegReaderStart(p, pSegcsr, &filter);
  while( SQLITE_OK==rc

  Fts3Phrase *p,                  /* Phrase to merge pList/nList into */
  int iToken,                     /* Token pList/nList corresponds to */
  char *pList,                    /* Pointer to doclist */
  int nList                       /* Number of bytes in pList */
){
  assert( iToken!=p->iDoclistToken );





  if( pList==0 ){
    sqlite3_free(p->doclist.aAll);
    p->doclist.aAll = 0;
    p->doclist.nAll = 0;
  }

  else if( p->iDoclistToken<0 ){

/* Flags allowed as part of the 4th argument to SegmentReaderIterate() */
#define FTS3_SEGMENT_REQUIRE_POS   0x00000001
#define FTS3_SEGMENT_IGNORE_EMPTY  0x00000002
#define FTS3_SEGMENT_COLUMN_FILTER 0x00000004
#define FTS3_SEGMENT_PREFIX        0x00000008
#define FTS3_SEGMENT_SCAN          0x00000010
#define FTS3_SEGMENT_FIRST         0x00000020

/* Type passed as 4th argument to SegmentReaderIterate() */
struct Fts3SegFilter {
  const char *zTerm;
  int nTerm;
  int iCol;
  int flags;

/* fts3.c */
int sqlite3Fts3PutVarint(char *, sqlite3_int64);
int sqlite3Fts3GetVarint(const char *, sqlite_int64 *);
int sqlite3Fts3GetVarint32(const char *, int *);
int sqlite3Fts3VarintLen(sqlite3_uint64);
void sqlite3Fts3Dequote(char *);
void sqlite3Fts3DoclistPrev(int,char*,int,char**,sqlite3_int64*,int*,u8*);

int sqlite3Fts3EvalPhraseStats(Fts3Cursor *, Fts3Expr *, u32 *);
int sqlite3Fts3FirstFilter(sqlite3_int64, char *, int, char *);

/* fts3_tokenizer.c */
const char *sqlite3Fts3NextToken(const char *, int *);
int sqlite3Fts3InitHashTable(sqlite3 *, Fts3Hash *, const char *);
int sqlite3Fts3InitTokenizer(Fts3Hash *pHash, const char *, 
    sqlite3_tokenizer **, char **
);

  int rc = SQLITE_OK;

  int isIgnoreEmpty =  (pCsr->pFilter->flags & FTS3_SEGMENT_IGNORE_EMPTY);
  int isRequirePos =   (pCsr->pFilter->flags & FTS3_SEGMENT_REQUIRE_POS);
  int isColFilter =    (pCsr->pFilter->flags & FTS3_SEGMENT_COLUMN_FILTER);
  int isPrefix =       (pCsr->pFilter->flags & FTS3_SEGMENT_PREFIX);
  int isScan =         (pCsr->pFilter->flags & FTS3_SEGMENT_SCAN);
  int isFirst =        (pCsr->pFilter->flags & FTS3_SEGMENT_FIRST);

  Fts3SegReader **apSegment = pCsr->apSegment;
  int nSegment = pCsr->nSegment;
  Fts3SegFilter *pFilter = pCsr->pFilter;
  int (*xCmp)(Fts3SegReader *, Fts3SegReader *) = (
    p->bDescIdx ? fts3SegReaderDoclistCmpRev : fts3SegReaderDoclistCmp
  );

    ){
      nMerge++;
    }

    assert( isIgnoreEmpty || (isRequirePos && !isColFilter) );
    if( nMerge==1 
     && !isIgnoreEmpty 
     && !isFirst 
     && (p->bDescIdx==0 || fts3SegReaderIsPending(apSegment[0])==0)
    ){
      pCsr->nDoclist = apSegment[0]->nDoclist;
      if( fts3SegReaderIsPending(apSegment[0]) ){
        rc = fts3MsrBufferData(pCsr, apSegment[0]->aDoclist, pCsr->nDoclist);
        pCsr->aDoclist = pCsr->aBuffer;
      }else{

            pCsr->nBuffer = (nDoclist+nByte)*2;
            aNew = sqlite3_realloc(pCsr->aBuffer, pCsr->nBuffer);
            if( !aNew ){
              return SQLITE_NOMEM;
            }
            pCsr->aBuffer = aNew;
          }

          if( isFirst ){
            char *a = &pCsr->aBuffer[nDoclist];
            int nWrite;
           
            nWrite = sqlite3Fts3FirstFilter(iDelta, pList, nList, a);
            if( nWrite ){
              iPrev = iDocid;
              nDoclist += nWrite;
            }
          }else{
            nDoclist += sqlite3Fts3PutVarint(&pCsr->aBuffer[nDoclist], iDelta);
            iPrev = iDocid;
            if( isRequirePos ){
              memcpy(&pCsr->aBuffer[nDoclist], pList, nList);
              nDoclist += nList;
              pCsr->aBuffer[nDoclist++] = '\0';
            }
          }
        }

        fts3SegReaderSort(apSegment, nMerge, j, xCmp);
      }
      if( nDoclist>0 ){
        pCsr->aDoclist = pCsr->aBuffer;