rar 7z for dired-compress-file-suffixes and dired-compress-files-alist

rar 7z for dired-compress-file-suffixes and dired-compress-files-alist

[Uwe Brauer]

Hi

I was forced to generate 7z and rar archives for Windows users and
noticed that dired-compress-file-suffixes and dired-compress-files-alist
do not support these formats completely.


I have set these variables for me in order to support these formats
(provided that the relevant rar and 7z programs are installed)
accordingly and I could provide a patch. But I would like to know,
whether there are copyright issues, when adding these external programs.

Thanks and regards 

Uwe Brauer

Re: rar 7z for dired-compress-file-suffixes and dired-compress-files-alist

[Eli Zaretskii]

> From: Uwe Brauer <oub@mat.ucm.es>
> Date: Tue, 12 Jun 2018 17:09:36 +0200
> 
> I have set these variables for me in order to support these formats
> (provided that the relevant rar and 7z programs are installed)
> accordingly and I could provide a patch. But I would like to know,
> whether there are copyright issues, when adding these external programs.

Yes, AFAIK the full-featured versions that run on Windows are not Free
Software, and the Free variants are not capable of opening archives
one finds nowadays.

But I think you could use bsdtar (from libarchive) which is Free
Software, at least for 7z.  (I never tried, so I don't know how
capable it is.)

Re: rar 7z for dired-compress-file-suffixes and dired-compress-files-alist

[Uwe Brauer]

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>>> "Eli" == Eli Zaretskii <eliz@gnu.org> writes:

   >> From: Uwe Brauer <oub@mat.ucm.es>
   >> Date: Tue, 12 Jun 2018 17:09:36 +0200
   >> 
   >> I have set these variables for me in order to support these formats
   >> (provided that the relevant rar and 7z programs are installed)
   >> accordingly and I could provide a patch. But I would like to know,
   >> whether there are copyright issues, when adding these external programs.

   > Yes, AFAIK the full-featured versions that run on Windows are not Free
   > Software, and the Free variants are not capable of opening archives
   > one finds nowadays.

   > But I think you could use bsdtar (from libarchive) which is Free
   > Software, at least for 7z.  (I never tried, so I don't know how
   > capable it is.)

I tested the free tools (on Ubuntu 16.06) which generated and extracted
rar abd 7z files. I did not test their compatibility with the latest
version on windows.

Bsdtar indeed openes these formats as well, but as far as I can see,
does not generate these formats.

So it seems, that given the difficulties concerning technical and
copyright issues, that these formats should not be added officially.


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Re: rar 7z for dired-compress-file-suffixes and dired-compress-files-alist

[Óscar Fuentes]

Eli Zaretskii <eliz@gnu.org> writes:

>> I have set these variables for me in order to support these formats
>> (provided that the relevant rar and 7z programs are installed)
>> accordingly and I could provide a patch. But I would like to know,
>> whether there are copyright issues, when adding these external programs.
>
> Yes, AFAIK the full-featured versions that run on Windows are not Free
> Software, and the Free variants are not capable of opening archives
> one finds nowadays.

7z is LGPL/public domain.

Re: rar 7z for dired-compress-file-suffixes and dired-compress-files-alist

[Eli Zaretskii]

> From: Óscar Fuentes <ofv@wanadoo.es>
> Date: Tue, 12 Jun 2018 18:05:31 +0200
> 
> > Yes, AFAIK the full-featured versions that run on Windows are not Free
> > Software, and the Free variants are not capable of opening archives
> > one finds nowadays.
> 
> 7z is LGPL/public domain.

AFAIK, not all of the code that went into the Windows binary was under
that license.  But maybe my information is stale, I simply avoid these
tools altogether, given the wealth of good formats supported by
bsdtar.

Re: rar 7z for dired-compress-file-suffixes and dired-compress-files-alist

[Noam Postavsky]

On 12 June 2018 at 12:42, Eli Zaretskii <eliz@gnu.org> wrote:
>> From: Óscar Fuentes <ofv@wanadoo.es>
>> Date: Tue, 12 Jun 2018 18:05:31 +0200
>>
>> > Yes, AFAIK the full-featured versions that run on Windows are not Free
>> > Software, and the Free variants are not capable of opening archives
>> > one finds nowadays.
>>
>> 7z is LGPL/public domain.
>
> AFAIK, not all of the code that went into the Windows binary was under
> that license.  But maybe my information is stale

https://www.7-zip.org/license.txt says:

  7-Zip Copyright (C) 1999-2018 Igor Pavlov.

  The licenses for files are:

    1) 7z.dll:
         - The "GNU LGPL" as main license for most of the code
         - The "GNU LGPL" with "unRAR license restriction" for some code
         - The "BSD 3-clause License" for some code
    2) All other files: the "GNU LGPL".

[...]

  unRAR license restriction
  -------------------------

    The decompression engine for RAR archives was developed using source
    code of unRAR program.
    All copyrights to original unRAR code are owned by Alexander Roshal.

    The license for original unRAR code has the following restriction:

      The unRAR sources cannot be used to re-create the RAR
compression algorithm,
      which is proprietary. Distribution of modified unRAR sources in
separate form
      or as a part of other software is permitted, provided that it is clearly
      stated in the documentation and source comments that the code may
      not be used to develop a RAR (WinRAR) compatible archiver.