crcengine

0.4.0.post1 verified Sat May 09 auth: no python

A library for CRC calculation and code generation in Python. Current version 0.4.0.post1. Supports many CRC algorithms and can generate CRC code. Release cadence is sporadic.

pip install crcengine

Common errors

error AttributeError: module 'crcengine' has no attribute 'CrcParams' ↓

cause Using crcengine version <0.4.0 which does not have CrcParams.

fix

Upgrade crcengine: pip install --upgrade crcengine

error TypeError: new() got an unexpected keyword argument 'polynomial' ↓

cause Passing separate polynomial/seed arguments is deprecated in v0.4.0+ and removed in some versions? Actually it's deprecated but still works in 0.4.0. Might be removed later.

fix

Use CrcParams object: from crcengine import CrcParams; crcengine.new(CrcParams(...))

Warnings

deprecated Passing separate polynomial and seed arguments to crcengine.new() is deprecated since v0.4.0. Use CrcParams instead. ↓

fix Use from crcengine import CrcParams; params = CrcParams(...); crc = crcengine.new(params)

gotcha CRC polynomials under 8 bits wide caused an invalid shift and Exception before v0.4.0. Fixed in v0.4.0. ↓

fix Upgrade to v0.4.0+ or avoid polynomials <8 bits width.

gotcha Function crcengine.new() returns a callable that takes bytes, not a class instance. Do not attempt to create instances. ↓

fix Call the returned function directly: crc = crcengine.new('crc32'); crc(b'data')

Imports

crcengine
```
import crcengine
```

Quickstart

Compute CRC using predefined or custom parameters.

import crcengine

# Predefined algorithms available
crc = crcengine.new('crc32c')
data = b'hello world'
checksum = crc(data)
print(hex(checksum))  # e.g. 0x...

# Using CrcParams for custom CRC (v0.4.0+)
from crcengine import CrcParams
params = CrcParams(width=16, polynomial=0x8005, seed=0x0000, reflect_input=False, reflect_output=False, xor_out=0x0000)
crc16 = crcengine.new(params)
print(hex(crc16(b'test')))