35 lines
890 B
Plaintext
35 lines
890 B
Plaintext
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def check_value(data: bytes) -> int:
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# 初始化crc为0xFFFF
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crc = 0xFFFF
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# 循环处理每个数据字节
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for byte in data:
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# 将每个数据字节与crc进行异或操作
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crc ^= byte
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# 对crc的每一位进行处理
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for _ in range(8):
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# 如果最低位为1，则右移一位并执行异或0xA001操作(即0x8005按位颠倒后的结果)
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if crc & 0x0001:
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crc = (crc >> 1) ^ 0xA001
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# 如果最低位为0，则仅将crc右移一位
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else:
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crc = crc >> 1
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retH = int(crc / 256)
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retL = int(crc % 256)
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return retL * 256 + retH
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def check(data: bytes) -> int:
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if len(data) < 2:
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return False
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crc = check_value(data[:-2])
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crc_in_frame = data[-1] + data[-2] * 256
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if crc == crc_in_frame:
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return True
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return False
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