Libungif license not clear

[warmerdam]

The license of the libungif library code is unclear from the contents of gdal/frmts/gif/libungif. This needs to be researched and documented (in the README for instance) as part of the GDAL provenance review (update PROVENANCE.TXT when resolved).

Mateusz, could you dig around to work this out?

[Even Rouault]

Apparently, from ​http://sourceforge.net/projects/libungif, we can read : "License: MIT License "

There's also a COPYING in the CVS that reads :

    1 The GIFLIB distribution is Copyright (c) 1997  Eric S. Raymond
    2 
    3 Permission is hereby granted, free of charge, to any person obtaining a copy
    4 of this software and associated documentation files (the "Software"), to deal
    5 in the Software without restriction, including without limitation the rights
    6 to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
    7 copies of the Software, and to permit persons to whom the Software is
    8 furnished to do so, subject to the following conditions:
    9 
   10 The above copyright notice and this permission notice shall be included in
   11 all copies or substantial portions of the Software.
   12 
   13 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   14 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
   15 FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
   16 AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
   17 LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
   18 OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
   19 THE SOFTWARE.

However, the code is not exactly the same. ​http://libungif.cvs.sourceforge.net/libungif/libungif/lib/gif_lib.h?revision=1.1.1.1&view=markup rgives #define GIF_LIB_VERSION " Version 4.1, " whereas GDAL internal version give #define GIF_LIB_VERSION " Version 4.0, ". Other files are a bit different too (a bit longer in the libungif CVS repository)

Maybe we should update GDAL version from upstream CVS ?

Fedora Core 4 has a libunfig-4.1.3-3.fc4.2.i386.rpm package. Licence is also advertised as MIT: ​http://rpmfind.net//linux/RPM/fedora/updates/4/i386/libungif-4.1.3-3.fc4.2.i386.html

[Mateusz Łoskot]

Perhaps, the solution is not so simple.

Originally, Gershon Elber is the author of version 1.0 of the libungif, a part of GIFLIB package, released in 1989.

AFAIK, between 1990-1992, Eric S. Raymond became the maintainer of GIFLIB package and since then the package is available under terms of MIT license. On the linux.com, you can find a few interesting notes about the history of this package: ​Microsoft using Eric S. Raymond's code

The original GIFLIB package was included in MSDOS and compilers like Turbo C. I found an interesting note in an older version of its source code file - ​GIFRSIZE.C - check the VersionStr value:

static char *VersionStr =
        "Gif library module,\t\tGershon Elber\n\
        (C) Copyright 1989 Gershon Elber, Non commercial use only.\n";

Perhaps, it would be reasonable to contact Eric S. Raymond and ask him for clarifications of the status of old and new GIFLIB sources. What do you think?

Anyway, I updated README and added COPYING file to libungif package and included what we know so far (r12132).

[warmerdam]

The COPYING update looks good.

I think we can assume that Eric applied the MIT/X license with proper permissions from the original author. Please file a seperate ticket with no milestone to look into updating the code, potentially to use libgif (instead of libungif) if the "lzw patent risk" is clearly past history.

[Mateusz Łoskot]

The update task ticket is #1825