def retrieve(key, path):
epub = Epub()
epub.expand(path)
space = Space(epub)
line_order = LineOrder(key, len(space))
def read_int(bit_size):
bit_buffer = ''
for i in range(bit_size):
if space[line_order.next()]:
bit_buffer += '1'
else:
bit_buffer += '0'
return int(bit_buffer, 2)
header_size = read_int(HEADER_BIT_SIZE)
message_size = read_int(header_size)
message = ''
for i in range(0, message_size, CHAR_BIT_SIZE):
message += chr(read_int(CHAR_BIT_SIZE))
epub.cleanup()
return message
def store(key, message, in_path, out_path):
epub = Epub()
epub.expand(in_path)
space = Space(epub)
binary_message = ''.join([format(ord(x), '0'+str(CHAR_BIT_SIZE)+'b') for x in message])
message_size = format(len(binary_message), 'b')
header_size = format(len(message_size), '0'+str(HEADER_BIT_SIZE)+'b')
bits_to_write = header_size + message_size + binary_message
if (len(space)) < len(bits_to_write):
print 'Error, not enough space on the epub file'
line_order = LineOrder(key, len(space))
add_noise(space)
for bit in bits_to_write:
space[line_order.next()] = (bit == '1')
space.commit()
epub.contract(out_path)
