Python: unsigned 32 bit bitwise arithmetic

Question

Trying to answer to another post whose solution deals with IP addresses and netmasks, I got stuck with plain bitwise arithmetic.

Is there a standard way, in Python,

Answer 1

You can use ctypes and its c_uint32:

>>> import ctypes
>>> m = 0xFFFFFF00
>>> ctypes.c_uint32(~m).value
255L

So what I did here was casting ~m to a C 32-bit unsigned integer and retrieving its value back in Python format.

Answer 2

You can mask everything by 0xFFFFFFFF:

>>> m = 0xFFFFFF00
>>> allf = 0xFFFFFFFF
>>> ~m & allf
255L

Answer 3

This is a module that I created a long time ago, and it might be of help to you:

IPv4Utils

It provides at least a CIDR class with subnet arithmetic. Check the test cases at the end of the module for examples.

Answer 4

from numpy import uint32

Answer 5

You could also xor with 0xFFFFFFFF, which is equivalent to the "unsigned complement".

>>> 0xFFFFFF00 ^ 0xFFFFFFFF
255