TMP.py

import ast

def encode(input_file, output_file):
	payloads = [x.rstrip() for x in open(input_file)]

	# Append char count
	payloads_with_char_count = []
	for pl in payloads:
		payload_with_char_count = str(len(pl) + 2) + pl
		payloads_with_char_count.append(payload_with_char_count)

	# Convert to binary
	payloads_bin = []
	for pl in payloads_with_char_count:
		payloads_bin.append(ascii_to_binary(pl))

	# Calculate parity
	final_payloads = []
	for pl in payloads_bin:
		pl.append(calc_even_parity(pl))
		final_payloads.append(pl)

	print(final_payloads)

	with open(output_file, "w") as file:
		for i in final_payloads:
			st = ""
			for j in i:
				st += ("[\'" + j + "\'], ")

			st = '[' + st[:-2] + ']'
			
			file.write(st + '\n')


def calc_even_parity(chars_list):
	res = int('0b' + chars_list[0], 2)

	i = 0
	# apply xoring
	for c in chars_list:
		i += 1

		if i == 1:
			continue
		else:
			res ^= int('0b' + c, 2)

	bin_str = bin(res)[2:]
	bin_str = '0' * (8 - len(bin_str)) + bin_str

	return bin_str

def ascii_to_binary(str):
	bin_list = []
	for c in str:
		bin_str = bin(int.from_bytes(c.encode(), 'big'))[2:]
		bin_str = '0' * (8 - len(bin_str)) + bin_str

		bin_list.append(bin_str)

	return bin_list

def decode(input_file, output_file):
	# Decoding.
	file = open(output_file, "w")
	for line in open(input_file):
		# Get the frame
		pay_load = ast.literal_eval(line)

		# Get the number of characters as ascii int and in absolute.
		n = int('0b' + pay_load[0][0], 2)
		count = n - ord('0')

		# Validate the number of bytes is the same.
		if (count is not len(pay_load)):
			print("ERROR, BYTE COUNT MISMATCH")
			continue

		# Get the parity.
		parity = 0
		pay_load_bin = []
		for i in range(0 , count - 1):
			# print (int('0b' + pay_load[i][0], 2), pay_load[i], i)
			parity = parity ^ int('0b' + pay_load[i][0], 2)
			# print(parity)
			pay_load_bin.append(int('0b' + pay_load[i][0], 2))	

		if int ('0b' + pay_load[count - 1][0], 2) is not parity:
			print ("ERROR, PARITY MISMATCH")
			file.write("ERROR, PARITY MISMATCH")
			
		else :
			pay_load_string = ''
			for i in range(1, len(pay_load_bin)):
				pay_load_string += pay_load_bin[i].to_bytes((n.bit_length() + 7) // 8, 'big').decode()
			file.write(pay_load_string + '\n')
			print (pay_load_string)
	file.close()

encode("payloads.txt", "encode_outputfile.txt")
decode("encode_outputfile.txt", "decode_outputfile.txt")