This is the README file for lzw, small, low level, pure python module for simple, stream-friendly data compression, built around iterators. Please see the accompanying LICENSE.txt file for license terms.
lzw currently requires python 2.7 or python 3.4 to run.
Before going on, potential users are advised to take a look at the gzip, zlib, bz2, zipfile, and tarfile modules available in the python standard library, which are dynamite-fast, mature, well supported, and generally awesome.
Seriously, check them out! You've already got them!
This software is in Pre-Alpha release, any bug reports (or even stories about ways you use the software, or wish you could use the software) are appreciated! Mail joerbowers@joe-bowers.com with your info.
INSTALLING
you should be able to install this package with
python setup.py install
Ok, moving on.
The easiest way to use lzw is probably something like this
import lzw
infile = lzw.readbytes("My Uncompressed File.txt") compressed = lzw.compress(infile) lzw.writebytes("My Compressed File.lzw", compressed)
Then later (or elsewhere)
infile = lzw.readbytes("My Compressed File.lzw", compressed) uncompressed = lzw.decompress(infile) for bt in uncompressed: do_something_awesome_with_this_byte(bt)
See the module documentation for more details.
The underlying compression algorithm for this module is as expressed in section 13 of the TIFF 6.0 specification, pages 58 to 62, available at the time of this writing on-line at
http://partners.adobe.com/public/developer/en/tiff/TIFF6.pdfWherever possible, I've tried to adhere to the algorithm and conventions that are described (in exhaustive and yet very readable detail!) in that document, even when it gets a bit Tiff specific. Where there are differences, they are likely bugs in this code.
Current dev priorities:
For now