BigInt always gives me the wiggins when I try to use it. I don't know whether this is going to explode, or work perfectly.

snippet.pl

sub as_n128 {
    my $self = shift;
    my $rv;
    {
        use Math::BigInt try => 'GMP,Pari,Calc';
        my $accum = Math::BigInt->new('0');
        my $factor = Math::BigInt->new('1')->blsft(Math::BigInt->new('32'));
        for my $i (map { $_ * 4 } 0 .. 3) {
            $accum->bmul($factor);
            $accum->badd(Math::Bigint->new('' . unpack 'N32', substr($self->{ address }, $i, 4)));
        }
        $rv = "$accum";
        no Math::BigInt;
    }
    return $rv;
}