35 lines
808 B
Python
35 lines
808 B
Python
# -*- coding: utf-8 -*-
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class ChkSum:
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def __init__(self):
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self.chksum = 0
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self.chksum_without_last = 0
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self.last_byte = 0xff
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def add(self, data):
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for c in data[:-1]:
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self.chksum += c
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self.chksum_without_last = self.chksum
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self.chksum_without_last &= 0xff
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self.last_byte = data[-1]
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self.chksum += self.last_byte
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self.chksum &= 0xff
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def get(self):
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remainder = ( 0x100 - self.chksum ) & 0xff
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return remainder
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def get_sum(self):
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return self.chksum
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def is_valid(self):
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return (self.chksum == 0)
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def get_expected(self):
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expected = ( 0x100 - self.chksum_without_last ) & 0xff
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return expected
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def get_last_byte(self):
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return self.last_byte
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