function deflate_rle()

in TestApplications/JDIChromePlugin/DevPanel/libs/jszip/jszip.js [4812:4901]

• 64 lines of code
• 28 McCabe index (conditional complexity)

function deflate_rle(s, flush) {
  var bflush;            /* set if current block must be flushed */
  var prev;              /* byte at distance one to match */
  var scan, strend;      /* scan goes up to strend for length of run */

  var _win = s.window;

  for (;;) {
    /* Make sure that we always have enough lookahead, except
     * at the end of the input file. We need MAX_MATCH bytes
     * for the longest run, plus one for the unrolled loop.
     */
    if (s.lookahead <= MAX_MATCH) {
      fill_window(s);
      if (s.lookahead <= MAX_MATCH && flush === Z_NO_FLUSH) {
        return BS_NEED_MORE;
      }
      if (s.lookahead === 0) { break; } /* flush the current block */
    }

    /* See how many times the previous byte repeats */
    s.match_length = 0;
    if (s.lookahead >= MIN_MATCH && s.strstart > 0) {
      scan = s.strstart - 1;
      prev = _win[scan];
      if (prev === _win[++scan] && prev === _win[++scan] && prev === _win[++scan]) {
        strend = s.strstart + MAX_MATCH;
        do {
          /*jshint noempty:false*/
        } while (prev === _win[++scan] && prev === _win[++scan] &&
                 prev === _win[++scan] && prev === _win[++scan] &&
                 prev === _win[++scan] && prev === _win[++scan] &&
                 prev === _win[++scan] && prev === _win[++scan] &&
                 scan < strend);
        s.match_length = MAX_MATCH - (strend - scan);
        if (s.match_length > s.lookahead) {
          s.match_length = s.lookahead;
        }
      }
      //Assert(scan <= s->window+(uInt)(s->window_size-1), "wild scan");
    }

    /* Emit match if have run of MIN_MATCH or longer, else emit literal */
    if (s.match_length >= MIN_MATCH) {
      //check_match(s, s.strstart, s.strstart - 1, s.match_length);

      /*** _tr_tally_dist(s, 1, s.match_length - MIN_MATCH, bflush); ***/
      bflush = trees._tr_tally(s, 1, s.match_length - MIN_MATCH);

      s.lookahead -= s.match_length;
      s.strstart += s.match_length;
      s.match_length = 0;
    } else {
      /* No match, output a literal byte */
      //Tracevv((stderr,"%c", s->window[s->strstart]));
      /*** _tr_tally_lit(s, s.window[s.strstart], bflush); ***/
      bflush = trees._tr_tally(s, 0, s.window[s.strstart]);

      s.lookahead--;
      s.strstart++;
    }
    if (bflush) {
      /*** FLUSH_BLOCK(s, 0); ***/
      flush_block_only(s, false);
      if (s.strm.avail_out === 0) {
        return BS_NEED_MORE;
      }
      /***/
    }
  }
  s.insert = 0;
  if (flush === Z_FINISH) {
    /*** FLUSH_BLOCK(s, 1); ***/
    flush_block_only(s, true);
    if (s.strm.avail_out === 0) {
      return BS_FINISH_STARTED;
    }
    /***/
    return BS_FINISH_DONE;
  }
  if (s.last_lit) {
    /*** FLUSH_BLOCK(s, 0); ***/
    flush_block_only(s, false);
    if (s.strm.avail_out === 0) {
      return BS_NEED_MORE;
    }
    /***/
  }
  return BS_BLOCK_DONE;
}