IPv6::uncompress( string $ip ): string

41    public static function uncompress(string $ip)42    {43        $c1 = -1;44        $c2 = -1;45        if (substr_count($ip, '::') === 1) {46            [$ip1, $ip2] = explode('::', $ip);47            if ($ip1 === '') {48                $c1 = -1;49            } else {50                $c1 = substr_count($ip1, ':');51            }52            if ($ip2 === '') {53                $c2 = -1;54            } else {55                $c2 = substr_count($ip2, ':');56            }57            if (strpos($ip2, '.') !== false) {58                $c2++;59            }60            // ::61            if ($c1 === -1 && $c2 === -1) {62                $ip = '0:0:0:0:0:0:0:0';63            }64            // ::xxx65            elseif ($c1 === -1) {66                $fill = str_repeat('0:', 7 - $c2);67                $ip = str_replace('::', $fill, $ip);68            }69            // xxx::70            elseif ($c2 === -1) {71                $fill = str_repeat(':0', 7 - $c1);72                $ip = str_replace('::', $fill, $ip);73            }74            // xxx::xxx75            else {76                $fill = ':' . str_repeat('0:', 6 - $c2 - $c1);77                $ip = str_replace('::', $fill, $ip);78            }79        }80        return $ip;81    }