Online PHP editor | refs for oNbev

<?php function createStringFromMap($map) { $chars = array('C*'); end($map); $last = key($map); for ($i = $j = $char = 0; $i <= $last; $i++) { $char |= ($map[$i] << (7 - $j)); if (++$j === 8) { $chars[] = $char; $j = $char = 0; } } return call_user_func_array('pack', $chars); } $map = array(); $map[1] = 1; $map[9] = 1; $map[17] = 1; $map[25] = 1; echo createStringFromMap($map);