> What if unconsumed_tail is not empty but less than needed to decompress at > least one byte? We need read more data until unconsumed_tail grow enought to > be decompressed. This is possible in zlib, but not in bz2. According to the manual [1], it is perfectly OK to supply one byte at a time. For xz, I'm not sure whether this problem could occur. I had assumed that it could not, but I may be mistaken ;-). Unfortunately liblzma has no proper manual, so I'll have to dig into the implementation to find out, and I haven't had the time to do this yet. [As an aside, it would be nice if the documentation for the zlib module mentioned this problem. We can't assume that users of the Python module are familiar with the C API for zlib...] [1] http://www.bzip.org/1.0.5/bzip2-manual-1.0.5.html