<?php
function Rot47($string)
{
	$return_string = '';
	$chars = preg_split('//', $string, -1, PREG_SPLIT_NO_EMPTY);
	foreach ($chars AS $char)
	{
		$return_string .= Rot47_char($char);
	}
	return $return_string;
}

function Rot47_char($char)
{
	if ($char == ' ')
		return ' ';

	$ascii = ord($char);
	$ascii += 47;
	if ($ascii > 126) $ascii -= 94;
	if ($ascii < 33) $ascii += 94;

	return chr($ascii);
}

var_dump(Rot47("Mooo"));

?>