base32.py (b32c.py improved)

#!/usr/bin/env python2

from sys import argv
from sys import exit

def add(a, b):
    return a + b

def lmodpad(str, n, ch):
    while len(str) % n > 0:
        str = ch + str

    return str

def int8_bin(n):
    return "".join(map(lambda power: "1" if n & 2**power else "0", xrange(7, -1, -1)))

def bin_b32(str):
    power_values = map(lambda power: int(str[4 - power]) * 2**power, xrange(4, -1, -1))

    return "0123456789ABCDEFGHIJKLMNOPQRSTUV"[reduce(add, power_values)]

def ascii_b32(str):
    binstr = lmodpad("".join(map(int8_bin, map(ord, str))), 5, "0")
    b32chars = map(lambda start: bin_b32(binstr[start : start + 5]), xrange(0, len(binstr), 5))

    return reduce(add, b32chars, "")

def b32_ascii(str):
    hexstr = "%02x" % int(str, 32)
    asciichars = map(lambda start: chr(int(hexstr[start : start + 2], 16)), xrange(0, len(hexstr), 2))

    return reduce(add, asciichars, "")

def usage():
    print "base32.py - encode and decode base32"
    print "usage: base32.py {-e|-d} string"
    print ""
    print "  -e  encode ascii to base32"
    print "  -d  decode base32 to ascii"
    exit(1)

def main():
    if len(argv) < 2:
        usage()

    if argv[1] == "-e":
        print ascii_b32(argv[2])

    elif argv[1] == "-d":
        print b32_ascii(argv[2])

    else:
        usage()

if __name__ == "__main__":
    main()