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import poly

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This commit is contained in:
Szymon Wojciechowski 2018-06-27 17:38:32 +00:00
parent bc3dcdaabe
commit f76cc9e06d
1 changed files with 2 additions and 68 deletions
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70
crc16.py
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@ -1,74 +1,8 @@
from poly import Polynomial
import sys import sys
import ast import ast
class Polynomial: Polynomial.n = 2
def __init__(self, coef_list):
self.degree = len(coef_list) - 1
self.coefficients = coef_list
@staticmethod
def add(p1, p2):
result = []
f = p1.coefficients
g = p2.coefficients
if len(f) >= len(g):
result = f
for i in range(0, len(g)):
result[i] = f[i] + g[i]
else:
result = g
for i in range(0, len(f)):
result[i] = f[i] + g[i]
result = [x % int(n) for x in result]
return Polynomial(result)
@staticmethod
def multiply(p1, p2):
result = [0] * (p1.degree + p2.degree + 1)
f = p1.coefficients
g = p2.coefficients
for i in range(0, len(f)):
for j in range(0, len(g)):
result[i+j] += f[i] * g[j]
result = [x % int(n) for x in result]
return Polynomial(result)
@staticmethod
def divide(p1, p2):
def inverse(x):
for i in range(1, int(n)):
r = (i * x) % int(n)
if r == 1:
break
else:
raise ZeroDivisionError
return i
if p1.degree < p2.degree:
return p1
f = p1.coefficients
g = p2.coefficients
g_lead_coef = g[-1]
g_deg = p2.degree
while len(f) >= len(g):
f_lead_coef = f[-1]
tmp_coef = f_lead_coef * inverse(g_lead_coef)
tmp_exp = len(f) - 1 - g_deg
tmp = []
for _ in range(tmp_exp):
tmp.append(0)
tmp.append(tmp_coef)
tmp_poly = Polynomial(tmp)
sub = Polynomial.multiply(p2, tmp_poly)
f = [x - y for x, y in zip(f, sub.coefficients)]
f = [x % int(n) for x in f]
while f and f[-1] == 0:
f.pop()
return Polynomial(f)
n = 2
def normalize_byte(data): def normalize_byte(data):
while len(data) != 8: while len(data) != 8: