Potential licensing issue with szip.dll

[surban]

HDF.PInvoke ships with SZIP in native/HDF5 1.10/bin64/szip.dll. According to https://portal.hdfgroup.org/display/HDF5/Szip+Compression+in+HDF+Products the SZIP library is licensed restrictively, only allowing non-commercial use without a paid license.

However, the COPYING file in the repository root does not state that restriction and the license of the NuGet package states:

HDF5 is available with the SZIP compression library but SZIP is not part of HDF5 and has separate copyright and license terms. See “Szip Compression in HDF Products” (https://support.hdfgroup.org/doc_resource/SZIP/) for further details.

Thus by solely reading the licensing terms, I would believe that the HDF.PInvoke NuGet package is free to use both for commercial and non-commercial products, which is indeed not the case due to the SZIP restrictions.

[gheber]

I believe the SZIP restriction applies only to the encoder part of SZIP (writing). There are no restrictions on reading (decoding). I also seem to remember that there is a compatible unrestricted implementation (https://www.dkrz.de/redmine/projects/aec/wiki/SZIP). We might need some clarification here. Thanks for bringing this up.

[epourmal]

Two points:

Free SZIP mentioned above is fully compatible with the SZIP library supported by The HDF Group and should be used instead of it.

It was my understanding that SZIP license terms only affect commercial distribution of encoded data. Everyone, including commercial organization, can use SZIP encoder and decoder internally.