Requests_IPv6::compress

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Summery Summery

Compresses an IPv6 address

Syntax Syntax

Requests_IPv6::compress( string $ip )

Description 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

Parameters Parameters

$ip

(string) (Required) An IPv6 address

Return Return

(string) The compressed IPv6 address

Source Source

File: 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];
		}
	}

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