Compresses an IPv6 address
Description
RFC 4291 allows you to compress consecutive zero pieces in an address to ‘::’. This method expects a valid IPv6 address and compresses consecutive zero pieces to ‘::’.
Example: FF01:0:0:0:0:0:0:101 -> FF01::101 0:0:0:0:0:0:0:1 -> ::1
See also
Parameters
$ip
stringrequired- An IPv6 address
Source
public static function compress($ip) {
// Prepare the IP to be compressed.
// Note: Input validation is handled in the `uncompress()` method, which is the first call made in this method.
$ip = self::uncompress($ip);
$ip_parts = self::split_v6_v4($ip);
// Replace all leading zeros
$ip_parts[0] = preg_replace('/(^|:)0+([0-9])/', '\1\2', $ip_parts[0]);
// Find bunches of zeros
if (preg_match_all('/(?:^|:)(?:0(?::|$))+/', $ip_parts[0], $matches, PREG_OFFSET_CAPTURE)) {
$max = 0;
$pos = null;
foreach ($matches[0] as $match) {
if (strlen($match[0]) > $max) {
$max = strlen($match[0]);
$pos = $match[1];
}
}
$ip_parts[0] = substr_replace($ip_parts[0], '::', $pos, $max);
}
if ($ip_parts[1] !== '') {
return implode(':', $ip_parts);
} else {
return $ip_parts[0];
}
}
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