A bitwise inversion of a Bignum sometimes yields odd results. As tested
ruby 1.8.5 (2006-08-25) [i686-linux]
./ruby -e 'a= “7fffff00”.hex ; b= “ffffff00”.hex ; printf “%b => %b\n”,
a, ~a ;
printf “%b => %b\n”, b, ~b’
1111111111111111111111100000000 => …10000000000000000000000011111111
11111111111111111111111100000000 => …1
In the first case, the ‘…1’ is expected, as per the documentation, but
annoying. Generally when I need to invert a number, I expect a result of
the same length as the original. Since ruby number classes are
inherently variable length I could not rely on the non-significant bits
even if I wanted to. Is it possible to put in a vote for a Bignum ~
operation to return a value of the same length as the largest argument?
The second case is just bizzare. Is this a bug?