PHP Function Number to Roman and Roman to Number

class konversi{
function roman2number($roman){
$conv = array(
array("letter" => 'I', "number" => 1),
array("letter" => 'V', "number" => 5),
array("letter" => 'X', "number" => 10),
array("letter" => 'L', "number" => 50),
array("letter" => 'C', "number" => 100),
array("letter" => 'D', "number" => 500),
array("letter" => 'M', "number" => 1000),
array("letter" => 0, "number" => 0)
);
$arabic = 0;
$state = 0;
$sidx = 0;
$len = strlen($roman);

while ($len >= 0) {
$i = 0;
$sidx = $len;

while ($conv[$i]['number'] > 0) {
if (strtoupper($roman[$sidx]) == $conv[$i]['letter']) {
if ($state > $conv[$i]['number']) {
$arabic -= $conv[$i]['number'];
} else {
$arabic += $conv[$i]['number'];
$state = $conv[$i]['number'];
}
}
$i++;
}

$len--;
}

return($arabic);
}


function number2roman($num,$isUpper=true) {
$n = intval($num);
$res = '';

/*** roman_numerals array ***/
$roman_numerals = 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);

foreach ($roman_numerals as $roman => $number)
{
/*** divide to get matches ***/
$matches = intval($n / $number);

/*** assign the roman char * $matches ***/
$res .= str_repeat($roman, $matches);

/*** substract from the number ***/
$n = $n % $number;
}

/*** return the res ***/
if($isUpper) return $res;
else return strtolower($res);
}
}