From: "Jon Smirl" <jonsmirl@gmail.com>
To: git <git@vger.kernel.org>
Subject: Compression and dictionaries
Date: Sun, 13 Aug 2006 23:37:21 -0400 [thread overview]
Message-ID: <9e4733910608132037t4297c3bbq9b0cd6ebaa03b979@mail.gmail.com> (raw)
>From what I remember from long ago most compression schemes build
dictionaries as a way of achieving significant compression. If so,
since we zlib compress each entry in a pack individually, are there
many copies of very similar dictionaries in the pack?
Some compression schemes support being initialized with a fixed
dictionary and sharing it over all entries. A fixed dictionary could
be built by analysing a large pack file. Sharing a compression
dictionary would probably be a win for me since I have 1M+ entries in
a pack.
Poking around in the zlib it appears that zlib supports precomputed
dictionaries.
http://www.zlib.net/manual.html
int deflateSetDictionary (z_streamp strm, const Bytef *dictionary,
uInt dictLength);
--
Jon Smirl
jonsmirl@gmail.com
next reply other threads:[~2006-08-14 3:37 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-08-14 3:37 Jon Smirl [this message]
2006-08-14 3:56 ` Compression and dictionaries Shawn Pearce
2006-08-14 4:07 ` Jon Smirl
2006-08-14 4:17 ` Shawn Pearce
2006-08-14 7:48 ` Alex Riesen
2006-08-14 10:06 ` Erik Mouw
2006-08-14 12:33 ` Johannes Schindelin
2006-08-14 14:08 ` Jon Smirl
2006-08-14 14:45 ` Johannes Schindelin
2006-08-14 16:15 ` Jon Smirl
2006-08-14 16:32 ` David Lang
2006-08-14 16:55 ` Jakub Narebski
2006-08-14 17:15 ` Jeff Garzik
2006-08-14 17:34 ` David Lang
2006-08-14 17:50 ` Jeff Garzik
2006-08-14 18:48 ` Jon Smirl
2006-08-14 19:08 ` David Lang
2006-08-14 19:38 ` Johannes Schindelin
2006-08-14 15:14 ` Alex Riesen
2006-08-14 15:26 ` Johannes Schindelin
-- strict thread matches above, loose matches on Subject: below --
2006-08-15 8:33 linux
2006-08-15 13:29 ` Jon Smirl
2006-08-15 14:55 ` Jon Smirl
2006-08-16 0:37 ` linux
[not found] ` <4b73d43f0608152243i15b37036x7aa50aa3afc2b02f@mail.gmail.com>
2006-08-16 5:50 ` Jon Smirl
2006-08-16 6:33 ` Johannes Schindelin
2006-08-16 6:55 ` Shawn Pearce
2006-08-16 7:09 ` Johannes Schindelin
2006-08-16 14:43 ` Jon Smirl
2006-08-17 22:33 ` linux
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