sub packwitharray {
    my $string = shift;
    return pack 'Cb*', length($string), join('', unpack '(b7)*', $string);
}

sub unpackwitharray {
    my ($length, $bits) = unpack 'Cb*', shift;
    my @chars = $bits =~ /.{7}/g;
    $#chars = $length - 1;
    return pack '(b7)*', @chars;
}