53204685c0
it's speed optimization as the inner code also checks that previous hash value is not same as new hash value. Essentially those two checks together makes the compression a little more efficient as it can remember matches further apart. As far as I remember from my tests, the secondary path was triggered only twice in very long uncompressed file, but the gain in compression rate was still noticeable. |
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|---|---|---|
| arch | ||
| doc | ||
| test | ||
| tools | ||
| win32 | ||
| .gitattributes | ||
| .gitignore | ||
| .travis.yml | ||
| adler32.c | ||
| ChangeLog.zlib | ||
| CMakeLists.txt | ||
| compress.c | ||
| configure | ||
| crc32.c | ||
| crc32.h | ||
| deflate_fast.c | ||
| deflate_medium.c | ||
| deflate_p.h | ||
| deflate_slow.c | ||
| deflate.c | ||
| deflate.h | ||
| FAQ.zlib | ||
| gzclose.c | ||
| gzguts.h | ||
| gzlib.c | ||
| gzread.c | ||
| gzwrite.c | ||
| INDEX | ||
| infback.c | ||
| inffast.c | ||
| inffast.h | ||
| inffixed.h | ||
| inflate.c | ||
| inflate.h | ||
| inftrees.c | ||
| inftrees.h | ||
| LICENSE.md | ||
| Makefile.in | ||
| match.c | ||
| match.h | ||
| README | ||
| README.md | ||
| README.zlib | ||
| treebuild.xml | ||
| trees.c | ||
| trees.h | ||
| uncompr.c | ||
| zconf.h.in | ||
| zlib.3 | ||
| zlib.3.pdf | ||
| zlib.h | ||
| zlib.map | ||
| zlib.pc.cmakein | ||
| zlib.pc.in | ||
| zutil.c | ||
| zutil.h | ||
Travis CI: 
zlib-ng - zlib for the next generation systems
Maintained by Hans Kristian Rosbach aka Dead2 (zlib-ng àt circlestorm dót org)
Fork Motivation and History
The motivation for this fork was due to seeing several 3rd party contributions containing new optimizations not getting implemented into the official zlib repository.
Mark Adler has been maintaining zlib for a very long time, and he has done a great job and hopefully he will continue for a long time yet. The idea of zlib-ng is not to replace zlib, but to co-exist as a drop-in replacement with a lower threshold for code change.
zlib has a long history and is incredibly portable, even supporting lots of systems that predate the Internet. This is great, but it does complicate further development and maintainability. The zlib code has to make numerous workarounds for old compilers that do not understand ANSI-C or to accommodate systems with limitations such as operating in a 16-bit environment.
Many of these workarounds are only maintenance burdens, some of them are pretty huge code-wise. For example, the [v]s[n]printf workaround code has a whopping 8 different implementations just to cater to various old compilers. With this many workarounds cluttered throughout the code, new programmers with an idea/interest for zlib will need to take some time to figure out why all of these seemingly strange things are used, and how to work within those confines.
So I decided to make a fork, merge all the Intel optimizations, merge the Cloudflare optimizations that did not conflict, plus a couple of other smaller patches. Then I started cleaning out workarounds, various dead code, all contrib and example code as there is little point in having those in this fork for different reasons.
Lastly I have been cleaning up the handling of different arches, so that it will be easier to implement arch-specific code without cluttering up the main code too much.
Now, there is still a lot to do and I am sure there are better ways of doing several of the changes I have done. And I would be delighted to receive patches, preferably as pull requests on github. Just remember that any code you submit must be your own and it must be zlib licensed.
Please read LICENSE.md, it is very simple and very liberal.
Acknowledgments
Big thanks to Raske Sider AS / raskesider.no for sponsoring my maintainership of zlib-ng.
The deflate format used by zlib was defined by Phil Katz. The deflate and zlib specifications were written by L. Peter Deutsch.
zlib was originally created by Jean-loup Gailly (compression) and Mark Adler (decompression).