Zaktualizuj 'hw3.py'
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hw3.py
348
hw3.py
@ -1,173 +1,177 @@
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from sys import argv
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from fractions import gcd
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class Polynomial():
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def __init__(self, lst, mod):
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self.poly = list(map(lambda x: x % mod, lst))
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self.mod = mod
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self.normalize()
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def normalize(self):
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while self.poly and self.poly[-1] == 0:
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self.poly.pop()
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#zwraca jednomian stopnia n
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@staticmethod
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def Monomial(n, c, mod):
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zeros = [0]*n
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zeros.append(c)
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return Polynomial(zeros, mod)
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def __add__(self, p2):
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p1 = self
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len_p1, len_p2= len(p1.poly), len(p2.poly)
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res = [0] * max(len_p1, len_p2)
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if len_p1 > len_p2:
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for _ in range(len_p1-len_p2):
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p2.poly.append(0)
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else:
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for _ in range(len_p2-len_p1):
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p1.poly.append(0)
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for i in range(len(res)):
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res[i] = (p1.poly[i] + p2.poly[i]) % self.mod
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return Polynomial(res, self.mod)
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def __sub__(self, p2):
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p1 = self
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res = []
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len_p2 = len(p2.poly)
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for i in range(len(p1.poly)):
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if i < len_p2:
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res.append(p1.poly[i] - p2.poly[i] % self.mod)
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else:
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res.append(p1.poly[i])
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return Polynomial(res, self.mod)
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def __mul__(self, p2):
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res = [0]*(len(self.poly)+len(p2.poly)-1)
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for i, x1 in enumerate(self.poly):
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for j, x2 in enumerate(p2.poly):
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res[i+j] += x1 * x2 % self.mod
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return Polynomial(res, self.mod)
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def __truediv__(self, p2):
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p1 = self
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m = self.mod
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if len(p1.poly) < len(p2.poly):
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return p1
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if len(p2.poly) == 0:
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raise ZeroDivisionError
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divisor_coeff = p2.poly[-1]
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divisor_exp = len(p2.poly) - 1
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while len(p1.poly) >= len(p2.poly):
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max_coeff_p1 = p1.poly[-1] #wspolczynnik przy najwyzszej potedze
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try:
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tmp_coeff = modDiv(max_coeff_p1, divisor_coeff, m)
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except ZeroDivisionError as e:
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raise e
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tmp_exp = len(p1.poly)-1 - divisor_exp
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tmp = [0] * tmp_exp
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tmp.append(tmp_coeff)
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sub = Polynomial(tmp, m) * p2
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p1 = p1 - sub
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p1.normalize()
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return Polynomial(p1.poly, m)
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def modDiv(a, b, m): # a*b^-1 (mod m)
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if gcd(b, m) != 1:
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raise ZeroDivisionError
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else:
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return (a * modinv(b, m)) % m
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#rozszerzony algorytm euklidesa
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def egcd(a, b):
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if a == 0:
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return (b, 0, 1)
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else:
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g, y, x = egcd(b % a, a)
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return (g, x - (b // a) * y, y)
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def modinv(a, m):
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g, x, y = egcd(a, m)
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return x % m
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#lista stringow binarnych -> lista intow 0/1
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def bin_str_to_list(lst):
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res = []
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for elem in lst:
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for ch in elem:
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res.append(int(ch))
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return res
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def mod8format(lst):
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while len(lst) % 8 != 0:
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lst.append(0)
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return lst
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def to_bin(x):
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data = bin(ord(x)).replace('b', '')
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while len(data) != 8:
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if len(data) < 8:
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data = str(0) + data
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else:
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data.replace(data[0], '')
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return data
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def to_ascii_val(lst):
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sum = 0
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for i in range(len(lst)):
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if lst[i] == 1:
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sum += 2**(7-i)
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return chr(sum)
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def data():
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p = bin_str_to_list(list(map(lambda x: to_bin(x), m)))
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p.reverse()
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Lx = Polynomial([1] * 16, 2) #L(x)
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X16 = Polynomial.Monomial(16, 1, 2) #X^16
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Gx = Polynomial([1,0,0,0,0,1,0,0,0,0,0,0,1,0,0,0,1], 2) #G(x)
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return (p, Lx, X16, Gx)
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def fcs(m):
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p, Lx, X16, Gx = data()
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Mx = Polynomial(p, 2) #M(x) #X^16
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Xnsub16 = Polynomial.Monomial(len(m)*8, 1, 2) #X^(n-16)
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rhs = Xnsub16 * Lx
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lhs = X16 * Mx
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xor = lhs + rhs
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fcs = xor/Gx
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#algorytm dzielenia ucina zera, trzeba dopelnic do 16 bitow
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for i in range(16 - len(fcs.poly)):
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fcs.poly.append(0)
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fcs.poly.reverse()
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return fcs.poly
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def check(m):
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p, Lx, X16, Gx = data()
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Xn = Polynomial.Monomial(len(p), 1, 2) #X^n
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Cx = Polynomial(p, 2)
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Cx = X16 * Cx
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Cx.poly = mod8format(Cx.poly)
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Sx = (Cx + Xn * Lx) / Gx
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if Sx.poly == []:
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return True
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return False
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def main():
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global m
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m = list(argv[1])
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mode = argv[2] # flagi -e -d (encode, decode)
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if mode == '-e':
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res = fcs(m)
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fcs_ch1 = to_ascii_val(res[:8])
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fcs_ch2 = to_ascii_val(res[8:])
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m.append(fcs_ch1)
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m.append(fcs_ch2)
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print(''.join(m))
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elif mode == '-d':
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print(check(m))
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if __name__ == '__main__':
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from sys import argv
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from fractions import gcd
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from ast import literal_eval
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class Polynomial():
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def __init__(self, lst, mod):
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self.poly = list(map(lambda x: x % mod, lst))
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self.mod = mod
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self.normalize()
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def normalize(self):
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while self.poly and self.poly[-1] == 0:
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self.poly.pop()
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#zwraca jednomian stopnia n
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@staticmethod
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def Monomial(n, c, mod):
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zeros = [0]*n
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zeros.append(c)
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return Polynomial(zeros, mod)
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def __add__(self, p2):
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p1 = self
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len_p1, len_p2= len(p1.poly), len(p2.poly)
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res = [0] * max(len_p1, len_p2)
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if len_p1 > len_p2:
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for _ in range(len_p1-len_p2):
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p2.poly.append(0)
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else:
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for _ in range(len_p2-len_p1):
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p1.poly.append(0)
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for i in range(len(res)):
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res[i] = (p1.poly[i] + p2.poly[i]) % self.mod
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return Polynomial(res, self.mod)
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def __sub__(self, p2):
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p1 = self
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res = []
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len_p2 = len(p2.poly)
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for i in range(len(p1.poly)):
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if i < len_p2:
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res.append(p1.poly[i] - p2.poly[i] % self.mod)
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else:
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res.append(p1.poly[i])
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return Polynomial(res, self.mod)
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def __mul__(self, p2):
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res = [0]*(len(self.poly)+len(p2.poly)-1)
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for i, x1 in enumerate(self.poly):
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for j, x2 in enumerate(p2.poly):
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res[i+j] += x1 * x2 % self.mod
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return Polynomial(res, self.mod)
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def __truediv__(self, p2):
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p1 = self
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m = self.mod
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if len(p1.poly) < len(p2.poly):
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return p1
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if len(p2.poly) == 0:
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raise ZeroDivisionError
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divisor_coeff = p2.poly[-1]
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divisor_exp = len(p2.poly) - 1
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while len(p1.poly) >= len(p2.poly):
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max_coeff_p1 = p1.poly[-1] #wspolczynnik przy najwyzszej potedze
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try:
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tmp_coeff = modDiv(max_coeff_p1, divisor_coeff, m)
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except ZeroDivisionError as e:
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raise e
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tmp_exp = len(p1.poly)-1 - divisor_exp
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tmp = [0] * tmp_exp
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tmp.append(tmp_coeff)
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sub = Polynomial(tmp, m) * p2
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p1 = p1 - sub
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p1.normalize()
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return Polynomial(p1.poly, m)
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def modDiv(a, b, m): # a*b^-1 (mod m)
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if gcd(b, m) != 1:
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raise ZeroDivisionError
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else:
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return (a * modinv(b, m)) % m
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#rozszerzony algorytm euklidesa
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def egcd(a, b):
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if a == 0:
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return (b, 0, 1)
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else:
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g, y, x = egcd(b % a, a)
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return (g, x - (b // a) * y, y)
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def modinv(a, m):
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g, x, y = egcd(a, m)
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return x % m
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#lista stringow binarnych -> lista intow 0/1
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def bin_str_to_list(lst):
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res = []
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for elem in lst:
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for ch in elem:
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res.append(int(ch))
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return res
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def mod8format(lst):
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while len(lst) % 8 != 0:
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lst.append(0)
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return lst
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def to_bin(x):
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data = bin(ord(x)).replace('b', '')
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while len(data) != 8:
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if len(data) < 8:
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data = str(0) + data
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else:
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data = data[1:]
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return data
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def to_ascii_val(lst):
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sum = 0
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for i in range(len(lst)):
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if lst[i] == 1:
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sum += 2**(7-i)
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return chr(sum)
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def data():
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p = bin_str_to_list(list(map(lambda x: to_bin(x), m)))
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p.reverse()
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Lx = Polynomial([1] * 16, 2) #L(x)
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X16 = Polynomial.Monomial(16, 1, 2) #X^16
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Gx = Polynomial([1,0,0,0,0,1,0,0,0,0,0,0,1,0,0,0,1], 2) #G(x)
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return (p, Lx, X16, Gx)
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def fcs(m):
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p, Lx, X16, Gx = data()
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Mx = Polynomial(p, 2) #M(x) #X^16
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Xnsub16 = Polynomial.Monomial(len(m)*8, 1, 2) #X^(n-16)
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rhs = Xnsub16 * Lx
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lhs = X16 * Mx
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xor = lhs + rhs
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fcs = xor/Gx
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#algorytm dzielenia ucina zera, trzeba dopelnic do 16 bitow
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for i in range(16 - len(fcs.poly)):
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fcs.poly.append(0)
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fcs.poly.reverse()
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return fcs.poly
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def check(m):
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p, Lx, X16, Gx = data()
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Xn = Polynomial.Monomial(len(p), 1, 2) #X^n
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Cx = Polynomial(p, 2)
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Cx = X16 * Cx
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Cx.poly = mod8format(Cx.poly)
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Sx = (Cx + Xn * Lx) / Gx
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if Sx.poly == []:
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return True
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return False
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def main():
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global m
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m = list(argv[2])
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mode = argv[1] # flagi -e -d (encode, decode)
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if mode == '-e':
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res = fcs(m)
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fcs_ch1 = to_ascii_val(res[:8])
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fcs_ch2 = to_ascii_val(res[8:])
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m.append(fcs_ch1)
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m.append(fcs_ch2)
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print(m)
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elif mode == '-d':
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to_check = literal_eval(argv[3])
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m += to_check
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print(check(m))
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if __name__ == '__main__':
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main()
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