SQLite

/*************************************************************************
** Start of highlight() implementation.
*/
typedef struct HighlightContext HighlightContext;
struct HighlightContext {
  /* Constant parameters to fts5HighlightCb() */

  int iRangeStart;                /* First token to include */
  int iRangeEnd;                  /* If non-zero, last token to include */
  const char *zOpen;              /* Opening highlight */
  const char *zClose;             /* Closing highlight */
  const char *zIn;                /* Input text */
  int nIn;                        /* Size of input text in bytes */

  /* Variables modified by fts5HighlightCb() */
  CInstIter iter;                 /* Coalesced Instance Iterator */
  int iPos;                       /* Current token offset in zIn[] */
  int iOff;                       /* Have copied up to this offset in zIn[] */
  int bOpen;                      /* True if highlight is open */
  char *zOut;                     /* Output value */
};

/*
** Append text to the HighlightContext output string - p->zOut. Argument
** z points to a buffer containing n bytes of text to append. If n is 
** negative, everything up until the first '\0' is appended to the output.

** Tokenizer callback used by implementation of highlight() function.
*/
static int fts5HighlightCb(
  void *pContext,                 /* Pointer to HighlightContext object */
  int tflags,                     /* Mask of FTS5_TOKEN_* flags */
  const char *pToken,             /* Buffer containing token */
  int nToken,                     /* Size of token in bytes */
  int iStartOff,                  /* Start byte offset of token */
  int iEndOff                     /* End byte offset of token */
){
  HighlightContext *p = (HighlightContext*)pContext;
  int rc = SQLITE_OK;
  int iPos;

  UNUSED_PARAM2(pToken, nToken);

  if( tflags & FTS5_TOKEN_COLOCATED ) return SQLITE_OK;
  iPos = p->iPos++;

  if( p->iRangeEnd>=0 ){
    if( iPos<p->iRangeStart || iPos>p->iRangeEnd ) return SQLITE_OK;
    if( p->iRangeStart && iPos==p->iRangeStart ) p->iOff = iStartOff;
  }

  /* If the parenthesis is open, and this token is not part of the current
  ** phrase, and the starting byte offset of this token is past the point
  ** that has currently been copied into the output buffer, close the
  ** parenthesis. */
  if( p->bOpen 
   && (iPos<=p->iter.iStart || p->iter.iStart<0)
   && iStartOff>p->iOff 
  ){
    fts5HighlightAppend(&rc, p, p->zClose, -1);
    p->bOpen = 0;
  }

  /* If this is the start of a new phrase, and the highlight is not open:
  **
  **   * copy text from the input up to the start of the phrase, and
  **   * open the highlight.
  */
  if( iPos==p->iter.iStart && p->bOpen==0 ){
    fts5HighlightAppend(&rc, p, &p->zIn[p->iOff], iStartOff - p->iOff);
    fts5HighlightAppend(&rc, p, p->zOpen, -1);
    p->iOff = iStartOff;
    p->bOpen = 1;
  }

  if( iPos==p->iter.iEnd ){
    if( p->bOpen==0 ){
      assert( p->iRangeEnd>=0 );
      fts5HighlightAppend(&rc, p, p->zOpen, -1);
      p->bOpen = 1;
    }
    fts5HighlightAppend(&rc, p, &p->zIn[p->iOff], iEndOff - p->iOff);

    p->iOff = iEndOff;

    if( rc==SQLITE_OK ){
      rc = fts5CInstIterNext(&p->iter);
    }
  }

  if( iPos==p->iRangeEnd ){
    fts5HighlightAppend(&rc, p, &p->zIn[p->iOff], iEndOff - p->iOff);
    p->iOff = iEndOff;



  }

  return rc;
}

/*
** Implementation of highlight() function.

    if( rc==SQLITE_OK ){
      rc = fts5CInstIterInit(pApi, pFts, iCol, &ctx.iter);
    }

    if( rc==SQLITE_OK ){
      rc = pApi->xTokenize(pFts, ctx.zIn, ctx.nIn, (void*)&ctx,fts5HighlightCb);
    }
    if( ctx.bOpen ){
      fts5HighlightAppend(&rc, &ctx, ctx.zClose, -1);
    }
    fts5HighlightAppend(&rc, &ctx, &ctx.zIn[ctx.iOff], ctx.nIn - ctx.iOff);

    if( rc==SQLITE_OK ){
      sqlite3_result_text(pCtx, (const char*)ctx.zOut, -1, SQLITE_TRANSIENT);
    }
    sqlite3_free(ctx.zOut);
  }

    while( ctx.iter.iStart>=0 && ctx.iter.iStart<iBestStart && rc==SQLITE_OK ){
      rc = fts5CInstIterNext(&ctx.iter);
    }

    if( rc==SQLITE_OK ){
      rc = pApi->xTokenize(pFts, ctx.zIn, ctx.nIn, (void*)&ctx,fts5HighlightCb);
    }
    if( ctx.bOpen ){
      fts5HighlightAppend(&rc, &ctx, ctx.zClose, -1);
    }
    if( ctx.iRangeEnd>=(nColSize-1) ){
      fts5HighlightAppend(&rc, &ctx, &ctx.zIn[ctx.iOff], ctx.nIn - ctx.iOff);
    }else{
      fts5HighlightAppend(&rc, &ctx, zEllips, -1);
    }
  }
  if( rc==SQLITE_OK ){

do_execsql_test 7.1 {
  SELECT rowid FROM f WHERE +filename GLOB '*ир*';
} {20}
do_execsql_test 7.2 {
  SELECT rowid FROM f WHERE filename GLOB '*ир*';
} {20}


#-------------------------------------------------------------------------
reset_db
do_execsql_test 8.0 {
  CREATE VIRTUAL TABLE t1 USING fts5(y, tokenize=trigram);
  INSERT INTO t1 VALUES('abcdefghijklm');
}

foreach {tn match res} {
  1 "abc ghi"         "(abc)def(ghi)jklm"
  2 "def ghi"         "abc(defghi)jklm"
  3 "efg ghi"         "abcd(efghi)jklm"
  4 "efghi"           "abcd(efghi)jklm"
  5 "abcd jklm"       "(abcd)efghi(jklm)"
  6 "ijkl jklm"       "abcdefgh(ijklm)"
  7 "ijk ijkl hijk"   "abcdefg(hijkl)m"

} {
  do_execsql_test 8.1.$tn {
    SELECT highlight(t1, 0, '(', ')') FROM t1($match)
  } $res
}

do_execsql_test 8.2 {
  CREATE VIRTUAL TABLE ft2 USING fts5(a, tokenize="trigram");
  INSERT INTO ft2 VALUES('abc x cde');
  INSERT INTO ft2 VALUES('abc cde');
  INSERT INTO ft2 VALUES('abcde');
}

do_execsql_test 8.3 {
  SELECT highlight(ft2, 0, '[', ']') FROM ft2 WHERE ft2 MATCH 'abc AND cde';
} {
  {[abc] x [cde]}
  {[abc] [cde]}
  {[abcde]}
}

finish_test