packascii.py

#!/usr/bin/env python

def pack(s):
    binary_string = ''
    for c in s:
        binary_string += '{:07b}'.format(ord(c))
    binary_string += '0'*((8 - len(binary_string)) % 8)
    byte_string = ''
    for i in range(0, len(binary_string), 8):
        byte_string += chr(int(binary_string[i:i+8], 2))
    return byte_string
    
def unpack(s):
    binary_string = ''
    for c in s:
        binary_string += '{:08b}'.format(ord(c))
    binary_string = binary_string[:-(len(binary_string) % 7)]
    original_string = ''
    for i in range(0, len(binary_string), 7):
        original_string += chr(int(binary_string[i:i+7], 2))
    return original_string