/**
* Convert an IP address to a binary character string (i.e. "01111111000000000000000000000001")
*
* @param IPAddress $ip address object
*
* @return string
*/
protected function asBinaryString(IPAddress $ip)
{
$length = 4 === $ip->ipVersion() ? 4 : 16;
$binaryIp = $ip->asBinary();
$bits = '';
for ($i = 0; $i < $length; $i++) {
$byte = decbin(ord($binaryIp[$i]));
$bits .= substr("00000000" . $byte, -8);
}
return $bits;
}