convert Numbers to Roman Numbers with PHP

/**
 * @param int $number
 * @return string
 */
function numberToRomanRepresentation($number) {
    $map = array('M' => 1000, 'CM' => 900, 'D' => 500, 'CD' => 400, 'C' => 100, 'XC' => 90, 'L' => 50, 'XL' => 40, 'X' => 10, 'IX' => 9, 'V' => 5, 'IV' => 4, 'I' => 1);
    $returnValue = '';
    while ($number > 0) {
        foreach ($map as $roman => $int) {
            if($number >= $int) {
                $number -= $int;
                $returnValue .= $roman;
                break;
            }
        }
    }
    return $returnValue;
}

function romanNumber($n)
{
    // support for numbers greater than a thousand
    $ret1 = '';
    while ($n >= 1000) {
        $ret1 .= 'M';
        $n -= 1000;
    }

    $ret = '';
    if ($n > 0) {
        $n = (string) $n;
        $l = 'IVXLCDM';
        $j = 0; // goes by roman letters
        for ($i = strlen($n)-1; $i >= 0; --$i) { // goes by decimal number
            switch ($n[$i]) {
                case 0: $s = ''; break;
                case 1: $s = $l[$j]; break;
                case 2: $s = $l[$j].$l[$j]; break;
                case 3: $s = $l[$j].$l[$j].$l[$j]; break;
                case 4: $s = $l[$j].$l[$j+1]; break;
                case 5: $s = $l[$j+1]; break;
                case 6: $s = $l[$j+1].$l[$j]; break;
                case 7: $s = $l[$j+1].$l[$j].$l[$j]; break;
                case 8: $s = $l[$j+1].$l[$j].$l[$j].$l[$j]; break;
                case 9: $s = $l[$j].$l[$j+2]; break;
            }
            $j += 2;
            $ret = $s.$ret;
        }
    }

    return $ret1.$ret;
}