Winzip compression - version 9 format change

[Nomadin]

I noticed that the beta of Winzip 9 has a new compression algorithm.

WinZip 9.0 supports the "enhanced deflate" compression method. This compression method provides greater compression and reduces the size of your Zip files, saving you data transmission time and valuable disk space.
http://www.winzip.com/whatsnew90.htm

I know that Total Commander is using an Open Source version of Zip (Info-Zip). How long does it take for changes such as these to be incorporated into a project such as Info-Zip? Can changes like this actually be incorporated into Info-Zip or are the changes being made by WinZip proprietary in nature?

I also noticed that the Info-Zip project seems to be a little stale. Here is a quote from their site:

Future Plans
There may never be another major release of UnZip. Aside from the fact that Info-ZIP is slowly calcifying, so is the zipfile format itself. It badly needs a major upgrade to support large files, large file systems, and real timestamps.

Will Total Commander continue to rely on the older Zip format for its internal default data compression format?

Sorry for so many questions on one post. Thanks in advance for any information.

Jeff

[pdavit]

…or the biggest rival and the mother of zip: http://www.pkware.com

This http://www.pkware.com/products/developers/index.html?src=home can be a start although I would like the project to be implemented by the Info-Zip team to take some of the load off, of Christian.

Just in case Christian is willing to do the task:
DELPHI20.ZIP (ftp://ftp.pkware.com/delphi20.zip) - Borland Delphi v2.0 example for the PKWARE Data Compression Library for Win32 on Intel

Of course, we shouldn’t expect this to come for free you know guys.

[Maxwish]

If the format is not compatible then this can turn into a mess...

It's just like the RAR 2.x - RAR 3.x thing, but then 1000 times worse because ZIP compression is used in much more software. All older software will instantly become obsolete if it isn't updated to support the new compression format.

I vote they change the extension for their new format from .ZIP to .ZIP3 or something...

[djk]

I vote they change the extension for their new format from .ZIP to .ZIP3 or something...

You are right.
I got lot of .rar files in my company and... new format made a lot of problems to some of my friedns and clients It would be easier if it had changed extension (by default).

[Black Dog]

[face=courier]On 13-05-2003 22:58:54 +0000 MaxWish wrote:

M> It's just like the RAR 2.x - RAR 3.x thing, but then 1000
M> times worse

RAR/WinRAR v.2.90 support new format version UNpacking. So it wasn't a problem, actually...[/face]

[R.Nausedat]

Actually, the "enhanced deflate" compression method is not new and it is supported by quite a lot of zip readers (btw, not by WinRAR 3.x). Pkware (the stewart of the zip format) introduced this method with PKZIPW 4.0 two or three years ago.

However, the above is not the point. Winzip Computing introduced with Winzip 9 Beta a new encryption method for zip files, and this method is compatible to nothing else but Winzip. Since Winzip seems to have a rather large user base I'm just curious how many vendors are going to support this method.

R.Nausedat

[ghisler(Author)]

It seems that info-zip's unzip now supports this new deflate64 decompression method too! So I will probably add support for it.

Regarding the encryption, I will have to find a solution like with the current external unzip library. AES is a standard and well documented, so it should be possible to find out how it is implemented in Winzip.

[pdavit]

It seems that info-zip's unzip now supports this new deflate64 decompression method too! So I will probably add support for it.

Regarding the encryption, I will have to find a solution like with the current external unzip library. AES is a standard and well documented, so it should be possible to find out how it is implemented in Winzip.

Will the update include a solution to the 2GB barrier also? Is (will) that (be) supported by Info-Zip or by you Christian?

[JackFoo]

This is taken verbatim from winzip site:

Greater capacity
In addition to supporting the original Zip file format, WinZip 9.0 also supports the 64-bit extensions to the Zip file format. The extended format lets you store all the data you need in Zip files of virtually unlimited size.
The original Zip file format limited the number of member files in a Zip file to 65,535, and the maximum size of both the Zip file itself and any member file to 4 gigabytes. For all practical purposes, the 64-bit extended format eliminates all these restrictions. Using the extended format, the member file size, Zip file size, and number of member files you can add to a Zip file are limited only by your system's resources.

WinZip remains fully compatible with the original file format and uses the original format whenever possible. WinZip uses the 64-bit extended format only when the limits of the original format are exceeded.

This should probably answer your questions;

Cheers.

[pdavit]

No, no, no! I’ve read the details of the link about WinZip; I clearly mentioned if InfoZip will support that coz Christian in his post said: “…info-zip's unzip now supports this new deflate64 decompression method..”

By the use of the word “now” I assumed that InfoZip is constantly updated and since Christian is making use of it for TC I just wanted to know if the capability of having zip files over 2GBs has been encapsulated within the latest version of InfoZip and as a result of that if we are going to see this build within TC.

[R.Nausedat]

I just wanted to know if the capability of having zip files over 2GBs has been encapsulated within the latest version of InfoZip

No, it is not. Also, zip64 (archives > 4GB) is far different from deflate64, which is basically another compression method.

Actually, zip 2.04 archives are limited to 4 GB due to internal structures which describes fileoffsets etc. with 4 byte values. Some archivers are treating these values as signed values, so for those is the limit 2 GB.

zip64 was introduced by Pkware with PKZIPW 4.5 to overcome the 4 GB limit, and this is the only way to create compatible zip archives > 4 GB.

By the use of the word “now” I assumed that InfoZip is constantly updated

The support for zip64 has beed discussed at the Info-Zip Group, but so far there is no code for this available. Even more, the good folks at Info-Zip are maintaining zip and unzip in their free time, and zip and unzip are supporing a ton of different OS's. It would be for sure impossible to add any new feature to them just after a vendor announced a new extension to the zip format.

R.Nausedat

[ghisler(Author)]

I'm considering to support zip files > 4 GB when Winzip supports them. Currently it makes no sense, because almost no unzip tools can handle them, so they would be incompatible. Since Winzip is the quasi-standard, I will only support what Winzip supports.

[Cobra]

Please add support for "deflate64" and "bzip2" methods of _ZIP_ compression. Both are suppoorted by 7-zip. www.7-zip.org

To make such archives in 7-zip, just type (in GUI) for additional parameters "m=deflate64" or "m=bzip2" w/o ""

[oblomov]

Please add support for "deflate64" and "bzip2" methods of _ZIP_ compression. Both are suppoorted by 7-zip. www.7-zip.org

To make such archives in 7-zip, just type (in GUI) for additional parameters "m=deflate64" or "m=bzip2" w/o ""

I would actually push the suggestion a little further. I would suggest to build 7-zip support in Total Commander as the default packer, since it can handle both .zip and .7z formats (TC could provide an option to let the user choose the default format, of course). This would allow TC to provide a comfortable interface to handle all the 7-zip options, which would be very nice.

[Hacker]

I would suggest to build 7-zip support in Total Commander as the default packer, since it can handle both .zip and .7z formats

That's not a very good point - RAR can handle both .zip and .rar formats, too. 7z is just "another incompatible format" and there is no reason to support it more or less than any other archiver supported by MultiArc.

Roman