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hex-in / libscrc

libscrc is a library for calculating CRC3 CRC4 CRC5 CRC6 CRC7 CRC8 CRC10 CRC11 CRC12 CRC15 CRC16 CRC24 CRC30 CRC31 CRC32 CRC64 CRC82
GNU General Public License v3.0
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Update _crc16module.c #12

Closed Tobi823 closed 1 year ago

Tobi823 commented 1 year ago

Thanks for your hard work. Your library helped me a lot and it much faster than my own C code :)

I spot a small error in the documentation for CRC-16/DNP.

According to this https://reveng.sourceforge.io/crc-catalogue/16.htm it should be Refin=True Refout=True. And it seems that libscrc.dnp already uses refin and refout.

import libscrc
import numpy as np

b1 = 0x82
b2 = 0xea

data = np.array([0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39, b1, b2], np.uint8)

# width=16 poly=0x3d65 init=0x0000 refin=true refout=true xorout=0xffff check=0xea82 residue=0x66c5 name="CRC-16/DNP"
val1 = libscrc.dnp(data)
val2 = libscrc.hacker16(data, poly=0x3d65, init=0x0000, refin=True, refout=True, xorout=0xffff, reinit=False)

print((val1 ^ 0xffff) == 0x66c5) # is True
print(val1 == val2) # is True