priv_key to wif (bitcoin)

<form method="post">
<input type="text" name="key" value="" />
<input type="submit" name="submit" value="Go" />
</form>
<?php
define("ADDRESSVERSION","80"); //this is a hex byte
if(isset($_POST))
{
    echo hash160ToAddress(trim(strtoupper($_POST['key'])));
}

function hash160ToAddress($hash160,$addressversion=null)
{
        if($addressversion === null)
        {
            $addressversion = ADDRESSVERSION;
        }
        $hash160=$addressversion.$hash160;
        $check=pack("H*" , $hash160);
        $check=hash("sha256",hash("sha256",$check,true));
        $check=substr($check,0,8);
        $hash160=strtoupper($hash160.$check);
        return encodeBase58($hash160);
}