xdelta3-python

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Fast delta encoding in python using xdelta3.

Requirements

• Python 3.5 or 3.6 - it's 2017, you should be using python 3.6 by now anyway.
• linux - compilation only tested on ubuntu, might work on other platform.

Installation

.. code:: shell

pip install xdelta3

Usage

.. code:: python

import xdelta3
value_one = b'wonderful string to demonstrate xdelta3, much of these two strings is the same.'
value_two = b'different string to demonstrate xdelta3, much of these two strings is the same.'
delta = xdelta3.encode(value_one, value_two)
# delta is an unreadable byte string: b'\xd6\xc3 ... \x01different\n\x13F\x00'

print(f'New string length: {len(value_two)}, delta length: {len(delta)}')
value_two_rebuilt = xdelta3.decode(value_one, delta)
if value_two_rebuilt == value_two:
    print('Boo Ya! Delta encoding successful.')

(with xdelta3 installed this code should run "as is", just copy it into ipython or a file and run)

How fast?

xdelta3-python is a thin wrapper around xdelta 3.1.1 <https://github.com/jmacd/xdelta/> which is a highly optimised c library for delta calculation and compression. It can encode a delta and decode it again for 5 small changes in a 5.5 million character string (the complete works of shakespeare) in around 10ms (or 30ms with the highest compression level). Boom. See performance.py <https://github.com/samuelcolvin/xdelta3-python/blob/master/performance.py>.

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