$str = '1000000000000100000000000000100';

    while (($pos = index($str, '1', ($pos ? $pos + 1 : 0)))
            >= 0)
    {
        push(@length, length($str) - $pos - 1);
        $pos++;
    }

    for (1 .. @length)
    {
        print "\$var$_ would get $length[$_-1] bits\n";
    }