hamming

Implementation of Hamming codes for detecting up to 2 errors and correcting up to 1 error in a data bitstring of arbitrary length. These are known as "SECDED" (Single Error Correction, Double Error Detection) codes and are extremely popular in computer memory for handling errors. For example, RAID-2 uses Hamming codes for its parity.

Files

hamming.py: The implementation. The two functions encode() and decode() form the main API; the rest are helper functions.

tests.py: A set of unit tests written while implementing hamming.py to verify its functionality.

Users only need import the encode and decode functions from the hamming module to make full use of it. The code has been verified to pass all 50+ unit tests in tests.py for Python 3.5+.

A brief example:

>>> from hamming import encode, decode
>>> from bitarray import bitarray
>>> data = bitarray('101010')
>>> data_with_parity = encode(data)
>>> data_with_parity[3] = not data_with_parity # data now has a single bit in error..
>>> decode(data_with_parity)                   # but Hamming codes can correct it!
bitarray('101010')