[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: More (de)compress?
From: |
Paul Eggert |
Subject: |
Re: More (de)compress? |
Date: |
Mon, 19 Aug 2013 09:41:49 -0700 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130803 Thunderbird/17.0.8 |
Thanks for taking this on. Some comments on the patch,
in addition to Eli's:
* It can be faster to compress using an external program,
since the compression can be done in parallel. Have you
timed your compression approach on a multicore platform,
and compared its real time to doing it with external
compression? (Similarly for decompression, though I
expect there we won't find the external program faster.)
You might try "pigz" for compression, since it's multicore
internally.
* There seems to be quite a bit of repetition in configure.ac
and in the C code -- each compression package does pretty
much the same thing with respect to allocating buffers,
saving point, etc. Could this be factored out to simplify
the code and make it easier to add future compression
algorithms?
* bzlib_detect and lzm_detect mishandle the case where the
buffer gap is located very near the start of the buffer.
* If the buffer contains random garbage,
(decompress-region nil 1 100000)
signals "Unsupported decompression method", which
isn't very clear. It should signal something like
"Unknown compression format".
* The functions compress-region and decompress-region
should be defined on all platforms, even those that
lack all compression libraries. They'll simply return
nil on such platforms, since they can't compress or
decompress anything. This simplifies the C code and
will simplify Lisp code too.