IPv6 address validation and manipulation utilities.

Source: wp-includes/Requests/src/Ipv6.php
Namespace: WpOrgRequests
Package: RequestsUtilities
Modifier: final

Overview

Provides methods to compress, uncompress, and validate IPv6 addresses. Handles the :: shorthand notation per RFC 4291 and supports IPv4-mapped IPv6 addresses (e.g., ::FFFF:129.144.52.38).

Public Methods

uncompress()

Expand an IPv6 address by replacing :: with the appropriate number of zero groups.

public static function uncompress( string|Stringable $ip ): string

Returns: string — Uncompressed IPv6 address.

Throws: InvalidArgument when the argument is not a string or stringable.

If the address does not contain exactly one ::, returns it unchanged. Accounts for IPv4-mapped addresses (presence of . in the second half).

Examples:

• FF01::101 → FF01:0:0:0:0:0:0:101
• ::1 → 0:0:0:0:0:0:0:1
• :: → 0:0:0:0:0:0:0:0

compress()

Compress an IPv6 address by replacing the longest run of consecutive zero groups with ::.

public static function compress( string $ip ): string

Returns: string — Compressed IPv6 address.

Internally calls uncompress() first, then split_v6_v4(). Strips leading zeros from each group, finds the longest sequence of zero groups, and replaces it with ::.

Examples:

• FF01:0:0:0:0:0:0:101 → FF01::101
• 0:0:0:0:0:0:0:1 → ::1

check_ipv6()

Validate an IPv6 address.

public static function check_ipv6( string $ip ): bool

Returns: bool — true if the address is valid.

Validates that:

• Pure IPv6: exactly 8 groups of 1–4 hex digits, each 0x0000–0xFFFF.
• IPv4-mapped: 6 IPv6 groups + 4 IPv4 octets (0–255, no leading zeros).
• No empty groups after uncompression.

Private Methods

split_v6_v4()

Split an IPv6 address into its IPv6 and IPv4 parts.

private static function split_v6_v4( string $ip ): string[]

Returns: Array where [0] is the IPv6 portion and [1] is the IPv4 portion (empty string if no IPv4 part).

Used by compress() and check_ipv6() to handle IPv4-mapped addresses like 0:0:0:0:0:FFFF:129.144.52.38.