IPv6::check_ipv6( string $ip ): bool

161    public static function check_ipv6(string $ip)162    {163        $ip = self::uncompress($ip);164        [$ipv6, $ipv4] = self::split_v6_v4($ip);165        $ipv6 = explode(':', $ipv6);166        $ipv4 = explode('.', $ipv4);167        if (count($ipv6) === 8 && count($ipv4) === 1 || count($ipv6) === 6 && count($ipv4) === 4) {168            foreach ($ipv6 as $ipv6_part) {169                // The section can't be empty170                if ($ipv6_part === '') {171                    return false;172                }173 174                // Nor can it be over four characters175                if (strlen($ipv6_part) > 4) {176                    return false;177                }178 179                // Remove leading zeros (this is safe because of the above)180                $ipv6_part = ltrim($ipv6_part, '0');181                if ($ipv6_part === '') {182                    $ipv6_part = '0';183                }184 185                // Check the value is valid186                $value = hexdec($ipv6_part);187                if ($value < 0 || $value > 0xFFFF) {188                    return false;189                }190                assert(is_int($value), 'For PHPStan: $value is only float when $ipv6_part > PHP_INT_MAX');191                if (dechex($value) !== strtolower($ipv6_part)) {192                    return false;193                }194            }195            if (count($ipv4) === 4) {196                foreach ($ipv4 as $ipv4_part) {197                    $value = (int) $ipv4_part;198                    if ((string) $value !== $ipv4_part || $value < 0 || $value > 0xFF) {199                        return false;200                    }201                }202            }203            return true;204        }205 206        return false;207    }