howeyc / crc16

Implements the 16-bit cyclic redundancy check, or CRC-16, checksum

CRC16

A Go package implementing the 16-bit Cyclic Redundancy Check, or CRC-16, checksum.

Usage

To generate the hash of a byte slice, use the crc16.Checksum() function:

import "github.com/howeyc/crc16"

data := byte("test")
checksum := crc16.Checksum(data, crc16.IBMTable)

The package provides the following hashing tables. For each of these tables, a shorthand can be used.

// This is the same as crc16.Checksum(data, crc16.IBMTable)
checksum := crc16.ChecksumIBM(data)

Using the hash.Hash interface also works.

h := crc16.New(crc16.IBMTable)
data := byte("test")
data2 := byte("data")
h.Write(data)
h.Write(data2)
checksum := h.Sum(nil)

Changelog

• 2017.03.27 - Added MBus checksum
• 2017.05.27 - Added checksum function without XOR
• 2017.12.08 - Implement encoding.BinaryMarshaler and encoding.BinaryUnmarshaler to allow saving and recreating their internal state.

crc16's Issues

How do I perform a ARK (aka CRC-16, CRC-IBM)?

It seems like it should be the IBM checksum, but I cannot get the library to produce sane values. I am comparing with results from here:
https://www.lammertbies.nl/comm/info/crc-calculation.html
and here:
http://www.zorc.breitbandkatze.de/crc.html

Easiest to compare is the "check" value from the description here:
http://reveng.sourceforge.net/crc-catalogue/all.htm

ascii string "123456789" should checksum to 0xbb3d

crc16 modbus seems to be wrong

http://crccalc.com/?crc=0x01%200x03%200x00%200x85%200x00%200x01&method=crc16&datatype=hex

It should be CRC-16/MODBUS = 0xE395 but it's not. I tried all the tables. What am I missing?

crc16 modbus giving wrong result

I tried getting crc for hex string 08000001 using crc16.ChecksumIBM. But instead of 84C3 it is giving me 3226. This is my code:
data := []byte("08000001")
checksum := crc16.ChecksumIBM(data)
fmt.Println("\n checksum:", checksum)

ChecksumCCITT wrong results

Hello,

I just tested the library and got Strange results:
for the "payloads" I have expected values for
[]byte{0x04} -> expected 0x40, 0x84 -> Result B6 5C
[]byte{0x08, 0x00, 0x00, 0x01, 0xF4} -> expected 0x9E, 0x87 -> Result 3D 24

I have double checked my expectations https://www.lammertbies.nl/comm/info/crc-calculation.html

I different crc implemention proofed my results.

Here my sample:

package main

import (
"fmt"

"github.com/howeyc/crc16"

)

func main() {
payload := []byte{0x04}
cs := crc16.ChecksumCCITT(payload)
fmt.Printf("Checksum: %x", cs)

}