Requests_IPv6::compress() │ public static │ WP 1.0

Compresses an IPv6 address

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

{} It's a method of the class: Requests_IPv6{}

No Hooks.

Return

String. The compressed IPv6 address

Usage

$result = Requests_IPv6::compress( $ip );
$ip(string) (required)
An IPv6 address

Notes

  • See: uncompress()

Code of Requests_IPv6::compress() WP 6.0

wp-includes/Requests/IPv6.php 
public static function compress($ip) {
	// Prepare the IP to be compressed
	$ip       = self::uncompress($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];
	}
}