PHP处理IP

/**
* Converts a printable IP into an unpacked binary string
*
* @author Mike Mackintosh - mike@bakeryphp.com
* @link http://www.highonphp.com/5-tips-for-working-with-ipv6-in-php
* @param string $ip
* @return string $bin
*/
public static function compressIp($ip)
{
    if (filter_var($ip, FILTER_VALIDATE_IP, FILTER_FLAG_IPV4)) {
        return current(unpack('A4', inet_pton($ip)));
    }
    elseif (filter_var($ip, FILTER_VALIDATE_IP, FILTER_FLAG_IPV6)) {
        return current(unpack('A16', inet_pton($ip)));
    }
    return false;
}

/**
* Converts an unpacked binary string into a printable IP
*
* @author Mike Mackintosh - mike@bakeryphp.com
* @link http://www.highonphp.com/5-tips-for-working-with-ipv6-in-php
* @param string $str
* @return string $ip
*/
public static function expandIp($str)
{
    if (strlen($str) == 16 OR strlen($str) == 4) {
        return inet_ntop(pack("A".strlen($str), $str));
    }
    return false;
}