LZ4-frame library for Python (via C bindings)
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lz4
lz4framed Changes for 0.12.0 Jul 2, 2018
.gitignore Additional pypi packaging fixes Jan 25, 2016
CHANGELOG Changes for 0.13.0 Oct 22, 2018
CONTRIBUTING.md
LICENSE Licensing information update Feb 16, 2016
MANIFEST.in Include CHANGELOG in MANIFEST.in Feb 14, 2016
NOTICE
README.md
ez_setup.py
flake8.cfg Initial commit Oct 8, 2015
pylint.rc Updated to lz4 v1.8.0 Sep 5, 2017
setup.py
test.py

README.md

Overview

This is an LZ4-frame compression library for Python v3.2+ (and 2.7+), bound to Yann Collet's LZ4 C implementation.

Installing / packaging

# To get from PyPI
pip3 install py-lz4framed

# To only build extension modules inline (e.g. in repository)
python3 setup.py build_ext -i

# To build & install globally
python3 setup.py install

Notes

Usage

Single-function operation:

import lz4framed

compressed = lz4framed.compress(b'binary data')

uncompressed = lz4framed.decompress(compressed)

To iteratively compress (to a file or e.g. BytesIO instance):

with open('myFile', 'wb') as f:
    # Context automatically finalises frame on completion, unless an exception occurs
    with Compressor(f) as c:
        try:
            while (...):
               c.update(moreData)
        except Lz4FramedNoDataError:
            pass

To decompress from a file-like object:

with open('myFile', 'rb') as f:
    try:
        for chunk in Decompressor(f):
           decoded.append(chunk)
    except Lz4FramedNoDataError:
        # Compress frame data incomplete - error case
        ...

See also lz4framed/__main__.py for example usage.

Documentation

import lz4framed
print(lz4framed.__version__, lz4framed.LZ4_VERSION, lz4framed.LZ4F_VERSION)
help(lz4framed)

Command-line utility

python3 -mlz4framed
USAGE: lz4framed (compress|decompress) (INFILE|-) [OUTFILE]

(De)compresses an lz4 frame. Input is read from INFILE unless set to '-', in
which case stdin is used. If OUTFILE is not specified, output goes to stdout.

Tests

Static

This library has been checked using flake8 and pylint, using a modified configuration - see pylint.rc and flake8.cfg.

Unit

python3 -m unittest discover -v .

Why?

The only existing lz4-frame interoperable implementation I was aware of at the time of writing (lz4tools) had the following limitations:

  • Incomplete implementation in terms of e.g. reference & memory leaks on failure
  • Lack of unit tests
  • Not thread safe
  • Does not release GIL during low level (de)compression operations
  • Did not address the requirements for an external project