Simple decimal subnet mask calculator.

prefmask.py

#! /usr/bin/env python
# -*- coding: utf-8 -*-

# Simple decimal subnet mask calculator.
#
# How to use:
#   python prefmask.py <number>
#   i.e.: python prefmask.py 17
#
#
# (c) 2012 Moisés Cachay Tello
# This software can be distributed under the terms of the BSD License
#

import sys

def prefix_mask(number):
    mask_bin = ('1' * number) + ('0' * (32 - number))
    segments = [mask_bin[i:i+8] for i in range(0, 32, 8)]
    segments_dec = map(lambda n: str(int(n, 2)), segments)
    return '.'.join(segments_dec)

def main():
    if len(sys.argv) != 2 or \
        not (sys.argv[1].isdigit() and 0 < int(sys.argv[1]) < 33):
        print 'Usage: prefmask <number in range 1-32>'
        return

    prefix = int(sys.argv[1])

    print 'The decimal subnet mask for prefix /%s is %s' % \
        (prefix, prefix_mask(prefix))

if __name__ == '__main__':
    main()

setup.py

# -*- coding: utf-8 -*-
from distutils.core import setup
import py2exe

setup(
    name='Simple decimal subnet mask calculator.',
    version='0.1b',
    description='A simple console-driven decimal subnet mask calculator.',
    author=u'Moisés Cachay',
    author_email='mcachayt@gmail.com',
    license='BSD',
    scripts=['prefmask.py'],
    console=['prefmask.py'],
    options={'py2exe': {'bundle_files': 1}},
    zipfile=None
)