DiffFormatter::_block_header

protected DiffFormatter::_block_header($xbeg, $xlen, $ybeg, $ylen)

protected function _block_header($xbeg, $xlen, $ybeg, $ylen) {
  if ($xlen > 1) {
    $xbeg .= "," . ($xbeg + $xlen - 1);
  }
  if ($ylen > 1) {
    $ybeg .= "," . ($ybeg + $ylen - 1);
  }

  return $xbeg . ($xlen ? ($ylen ? 'c' : 'd') : 'a') . $ybeg;
}