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Python bindings to zopfli
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zopfli @ 1ca477e


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cPython bindings for zopfli.


pyzopfli is a straight forward wrapper around zopfli's ZlibCompress method.

from zopfli.zlib import compress
from zlib import decompress
s = 'Hello World'
print decompress(compress(s))

pyzopfli also wraps GzipCompress, but the API point does not try to mimic the gzip module.

from zopfli.gzip import compress
from StringIO import StringIO
from gzip import GzipFile
print GzipFile(fileobj=StringIO(compress("Hello World!"))).read()

Both zopfli.zlib.compress and zopfli.gzip.compress support the following keyword arguments. All values should be integers; boolean parmaters are treated as expected, 0 and >0 as false and true.

  • verbose dumps zopfli debugging data to stderr
  • numiterations Maximum amount of times to rerun forward and backward pass to optimize LZ77 compression cost. Good values: 10, 15 for small files, 5 for files over several MB in size or it will be too slow.
  • blocksplitting If true, splits the data in multiple deflate blocks with optimal choice for the block boundaries. Block splitting gives better compression. Default: true (1).
  • blocksplittinglast If true, chooses the optimal block split points only after doing the iterative LZ77 compression. If false, chooses the block split points first, then does iterative LZ77 on each individual block. Depending on the file, either first or last gives the best compression. Default: false (0).
  • blocksplittingmax Maximum amount of blocks to split into (0 for unlimited, but this can give extreme results that hurt compression on some files). Default value: 15.


  • Stop reading the entire file into memory and support streaming
  • Monkey patch zlib and gzip so code with an overly tight binding can be easily modified to use zopfli.
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