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I need to extend my application to unzip .zipx files. This appears to be the latest and greatest zip compression from WinZip.

Does anyone know of a library that will do this?

Thanks

Ori Nachum
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Daniel Mitchell
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3 Answers3

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One thing I would suggest is looking here.

it seems they are open to developers.

http://www.winzip.com/comp_info.htm

Daniel A. White
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  • is right. In Download section, you can get the command line, which you can run from C# http://www.winzip.com/downcl.html – Ori Nachum Jan 19 '17 at 15:02
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According to Wikipedia WinZip uses .zipx as extension for Zip archives that use compression methods newer than deflate. Deflate is perhaps the minimum standard of Zip which everyone can compress or extract but newer algorithms like bzip2, LZMA or PPMd+ are also defined by the standard.

As for libraries which are able to handle newer compression algorithms you may have luck with SharpZipLib which implements at least bzip2 compression. There is also DotNetZip but it seems to be a little low on newer features.

Joey
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  • DotNetZip does DEFLATE. Does not currently do bzip2, LZMA or PPMd. – Cheeso Jul 30 '09 at 00:59
  • That was my fear. Didn't find much definitive info on their page, though. – Joey Jul 30 '09 at 01:07
  • (I wrote DotNetZip). I guess it would be possible to produce an LZMA and PPMd capability but never got a formal request. I looked at the LZMA SDK but my head spins when I see the code. Feasible, but it will take some effort. – Cheeso Jul 30 '09 at 04:34
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As Johannes Rossel mentioned SharpZipLib is a decent compression library written in C# and has source code available. This library is used in various projects as well and seems to have decent support. The only negative aspect is that I don't think they currently support WinZip's new zipx format. In fact I haven't found any other application or library that currently supports this new format other than WinZip. If you need a library for their new format probably the first place to start checking is with the WinZip support department to see if they have a native library available that could be wrapped or some specifications on the new format. If this file format is a closed spec then unfortunately you may not have many options.

jpierson
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    It's still the old format. It's just a kind of marker that the archive uses newer compression algorithms than deflate. – Joey Jul 30 '09 at 01:08