hideMessage_textstego4.py

#-*- coding: windows-1251 -*-
# Todo: пока работает только с маленькими o

import sys
import os

def to_binary_string(s):
    binary_s = ''
    for c in s:
        binary_s += '{:08b}'.format(ord(c))
    return binary_s

def main():
    if len(sys.argv) != 4:
        print 'Usage: python %s <input-file> <message> <output-file>' % sys.argv[0]
        exit(1)

    input_file   = sys.argv[1]
    message      = sys.argv[2]
    output_file  = sys.argv[3]

    if not os.path.exists(input_file):
        print 'File "%s" does not exist' % input_file
        exit(1)

    message_binary = to_binary_string(message)
    print 'message_binary', message_binary

    with open(input_file) as f:
        container = f.read()

    assert(container.count('o') >= len(message_binary))

    indices = []
    for idx, c in enumerate(container):
        if c == 'o':
            indices.append(idx)

    container_lst = list(container)
    for idx, bit in enumerate(message_binary):
        if bit == '1':
            container_lst[indices[idx]] = ' # russian



    with open(output_file, 'w') as f:
        f.write(''.join(container_lst))

if __name__ == '__main__':
    main()