Rozwiązanie zadania "CRC" #24

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s426211 wants to merge 8 commits from (deleted):zad3 into master

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main.py Normal file
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import sys
import platform
def encode(m):
m = bytearray(m, "ascii")
message = format(int.from_bytes(m, "big"), "b")
generator = "10001000000100001"
gen_deg = len(generator)
message += "0" * (gen_deg - 1)
while len(message) % 8 != 0:
message = "0" + message
swapped = list(message)
for i in range(gen_deg - 1):
if swapped[i] == "0":
swapped[i] = "1"
else:
swapped[i] = "0"
message = "".join(swapped)
while True:
if message[0] == "0":
message = message[1:]
else:
chunk = message[:gen_deg]
if len(chunk) < gen_deg:
while len(chunk) % 8 != 0:
chunk = "0" + chunk
fb = str(hex(int(chunk[:8], 2)))[2:]
if len(fb) == 1:
fb = "0" + fb
sb = str(hex(int(chunk[8:], 2)))[2:]
if len(sb) == 1:
sb = "0" + sb
m += b"\\x" + bytes(fb, "ascii")
m += b"\\x" + bytes(sb, "ascii")
return m
remainder = format(int(chunk, 2) ^ int(generator, 2), "b")
message = remainder + message[gen_deg:]
def decode(n):
if platform.system() == "Windows":
n = n.split("\\\\x")
else:
n = n.split("\\x")
msg = n[0]
message = ""
for ch in msg:
ch = bin(ord(ch))[2:]
while len(ch) < 8:
ch = "0" + ch
message += str(ch)
fb = bin(int(n[1], 16))[2:]
while len(fb) < 8:
fb = "0" + fb
sb = bin(int(n[2], 16))[2:]
while len(sb) < 8:
sb = "0" + sb
message += fb + sb
generator = "10001000000100001"
gen_deg = len(generator)
while len(message) % 8 != 0:
message = "0" + message
swapped = list(message)
for i in range(gen_deg - 1):
if swapped[i] == "0":
swapped[i] = "1"
else:
swapped[i] = "0"
message = "".join(swapped)
while True:
if '1' not in message:
return True
if message[0] == "0":
message = message[1:]
else:
chunk = message[:gen_deg]
if len(chunk) < gen_deg:
return False
remainder = format(int(chunk, 2) ^ int(generator, 2), "b")
message = remainder + message[gen_deg:]
if __name__ == "__main__":
if len(sys.argv) < 2:
print("Proszę wprowadzić jedną z flag:\n")
print(" -e, --encode\tZakoduj <wiadomość>")
print(" -d, --decode\tDekoduj <wiadomość_z_ramką>\n")
print("Przykład:")
print("python main.py -e abc")
print("python main.py -d abc\\\\x51\\\\x4a")
else:
if sys.argv[1] == "-e" or sys.argv[1] == "--encode":
print(encode(sys.argv[2]))
elif sys.argv[1] == "-d" or sys.argv[1] == "--decode":
print(decode(sys.argv[2]))