vigenere_ascii (PHP)

/// vigenere_ascii(in,key,mode)
//
//  Returns the given string enciphered or deciphered
//  using a simple Vigenere style cipher, and filtering
//  out non-printable characters.
//
//      in          input, string
//      key         enciphering key, string
//      mode        0 = decipher, 1 = encipher
//
/// GMLscripts.com/license
function vigenere_ascii($in, $key, $mode)
{
    $out = "";
    $inLen = strlen($in);
    $keyLen = strlen($key);
    $loVal = 32;
    $hiVal = 126;
    $span = ($hiVal - $loVal) + 1;
    for ($pos=0; $pos<$inLen; $pos+=1) {
        $inChar = substr($in, $pos, 1);
        $keyChar = substr($key, $pos % $keyLen, 1);
        $inVal = min(max($loVal, ord($inChar)), $hiVal) - $loVal;
        $keyVal = min(max($loVal, ord($keyChar)), $hiVal) - $loVal;
        if ($mode) {
            $outVal = (($inVal + $keyVal) % $span) + $loVal;
        }else{
            $outVal = (($span + $inVal - $keyVal) % $span) + $loVal;
        }
        $outChar = chr($outVal);
        $out = $out . $outChar;
    }
    return $out;
}