Huffpy

Huffpy is a simple and efficient Huffman coding library for Python. It was written for a school project but I've since developed it further into a proper robust Python library.

What is Huffman coding?

Huffman coding is a lossless compression algorithm used for text which works by performing a frequency analysis and assigning bit patterns to each character based on how frequently it appears. You can find a better description on the Huffman coding Wikipedia page.

How do I install it?

Simply clone the repo and run python setup.py install to install the package. It has no dependencies, so there's no need to install any!

Example Programs

Here's a very simple program to demonstrate how easy it is to use Huffman coding with Huffpy.

import huffpy

coder = huffpy.HuffmanCoder()
stringToEncode = "Hello from Huffpy!"

huffmanString, tree = coder.encode(stringToEncode)
huffmanBytes = coder.toBytes(huffmanString, tree)

decodedHuffmanString, decodedTree = coder.fromBytes(huffmanBytes)
decodedString = coder.decode(decodedHuffmanString, decodedTree)

assert stringToEncode == decodedString

There's also a shortcuts module for common combinations of commands, so the above program could be written as follows:

import huffpy.shortcuts

stringToEncode = "Hello from Huffpy!"

huffmanBytes = huffpy.shortcuts.stringToHuffmanBytes(stringToEncode)
decodedString = huffpy.shortcuts.huffmanBytesToString(huffmanBytes)

assert stringToEncode == decodedString

Documentation

huffman.py

HuffmanCoder class

• encode(string, showOutput=False): encodes a regular string using Huffman coding, returning both the Huffman-coded string and its tree, in that order. If showOutput is true, show the percentage completed every 20000 characters.
• decode(string, tree): decodes a Huffman-coded string and its tree, returning the original uncompressed string.
• toBytes(string, tree): converts the Huffman-coded string and its tree into bytes, ready to be written to a file.
• fromBytes(_bytes): converts the bytes from toBytes back into a string and a tree, ready to be decoded.

shortcuts.py

• stringToHuffmanBytes(string): converts a regular string into Huffman-coded bytes, the equivalent of running encode followed by toBytes.
• huffmanBytesToString(_bytes): converts the Huffman-coded bytes back into a regular string, the equivalent of running fromBytes followed by decode.