SQLite

  ** expression that appear in the current row. If such a fragment of text
  ** cannot be found, the second iteration of the loop attempts to locate
  ** a pair of fragments, and so on.
  */
  int nSnippet = 0;               /* Number of fragments in this snippet */
  SnippetFragment aSnippet[4];    /* Maximum of 4 fragments per snippet */
  int nFToken = -1;               /* Number of tokens in each fragment */

  if( !pCsr->pExpr ){
    sqlite3_result_text(pCtx, "", 0, SQLITE_STATIC);
    return;
  }

  for(nSnippet=1; 1; nSnippet++){

    int iSnip;                    /* Loop counter 0..nSnippet-1 */
    u64 mCovered = 0;             /* Bitmask of phrases covered by snippet */
    u64 mSeen = 0;                /* Bitmask of phrases seen by BestSnippet() */

  const char *ZDUMMY;             /* Dummy argument used with xNext() */
  int NDUMMY;                     /* Dummy argument used with xNext() */
  int rc;                         /* Return Code */
  int nToken;                     /* Number of tokens in query */
  int iCol;                       /* Column currently being processed */
  StrBuffer res = {0, 0, 0};      /* Result string */
  TermOffsetCtx sCtx;             /* Context for fts3ExprTermOffsetInit() */

  if( !pCsr->pExpr ){
    sqlite3_result_text(pCtx, "", 0, SQLITE_STATIC);
    return;
  }

  memset(&sCtx, 0, sizeof(sCtx));
  assert( pCsr->isRequireSeek==0 );

  /* Count the number of terms in the query */
  rc = fts3ExprLoadDoclists(pCsr, 0, &nToken);
  if( rc!=SQLITE_OK ) goto offsets_out;

  return;
}

/*
** Implementation of matchinfo() function.
*/
void sqlite3Fts3Matchinfo(sqlite3_context *pContext, Fts3Cursor *pCsr){
  int rc;
  if( !pCsr->pExpr ){
    sqlite3_result_blob(pContext, "", 0, SQLITE_STATIC);
    return;
  }
  rc = fts3GetMatchinfo(pCsr);
  if( rc!=SQLITE_OK ){
    sqlite3_result_error_code(pContext, rc);
  }else{
    Fts3Table *pTab = (Fts3Table*)pCsr->base.pVtab;
    int n = sizeof(u32)*(2+pCsr->aMatchinfo[0]*pCsr->aMatchinfo[1]*3);
    if( pTab->bHasDocsize ){
      n += sizeof(u32)*(1 + 2*pTab->nColumn);
    }
    sqlite3_result_blob(pContext, pCsr->aMatchinfo, n, SQLITE_TRANSIENT);
  }
}

#endif

    {2 2 1 3 3 1 6 3 0 0 0 0 3 2}
    {2 2 1 3 3 1 6 3 0 0 0 0 3 2}
    {2 2 1 3 3 2 6 3 0 0 0 1 3 2}
    {2 2 1 3 3 2 6 3 0 0 0 1 3 2}
    {2 2 1 3 3 3 6 3 0 0 0 2 3 2}          
    {2 2 1 3 3 3 6 3 0 0 0 2 3 2}
  }]

  # EVIDENCE-OF: R-56101-59725 If used within a SELECT that uses the
  # "query by rowid" or "linear scan" strategies, then the snippet and
  # offsets both return an an empty string, and the matchinfo function
  # returns a blob value zero bytes in size.
  #
  set r 1000000                   ;# A rowid that exists in table ft
  do_select_test $T.10.0 { SELECT rowid FROM ft WHERE rowid = $r } $r
  do_select_test $T.10.1 {
    SELECT length(offsets(ft)), typeof(offsets(ft)) FROM ft;
  } {0 text 0 text 0 text}
  do_select_test $T.10.2 {
    SELECT length(offsets(ft)), typeof(offsets(ft)) FROM ft WHERE rowid = $r
  } {0 text}
  do_select_test $T.10.3 {
    SELECT length(snippet(ft)), typeof(snippet(ft)) FROM ft;
  } {0 text 0 text 0 text}
  do_select_test $T.10.4 {
    SELECT length(snippet(ft)), typeof(snippet(ft)) FROM ft WHERE rowid = $r;
  } {0 text}
  do_select_test $T.10.5 {
    SELECT length(matchinfo(ft)), typeof(matchinfo(ft)) FROM ft;
  } {0 blob 0 blob 0 blob}
  do_select_test $T.10.6 {
    SELECT length(matchinfo(ft)), typeof(matchinfo(ft)) FROM ft WHERE rowid = $r
  } {0 blob}
}


set sqlite_fts3_enable_parentheses 0
finish_test