Re: [CORE] GPL Source and Copyright Questions

Thomas Lockhart <lockhart@fourpalms.org> writes:
>> This code seems to have been inserted by Tom Lockhart on 1997-07-29
>> (geo_ops.c rev 1.13).  Tom, any info on the copyright status?

> None, beyond the info you already resurrected. I vaguely recall that I 
> did take the LJ letter as an invitation to reuse algorithms. I would 
> guess that I had possible licensing conflicts in mind so would have 
> tried to avoid them, but it would probably be best for someone to 
> evaluate that from the current code bases. I may have preserved the 
> Franks info for attribution of concepts to a specific person and version.

Thanks for answering, Tom.  Charles, since you were the one interested,
maybe you could compare the geo_ops.c code to the Franks code and see
if it looks like Tom borrowed code or just the algorithms?

> My (also vague) recollection is that the original Postgres algorithm was 
> just broken.

Yeah, I saw while tracing the CVS history that the code you replaced
defined "overlaps" as "bounding boxes overlap", which is surely not good
enough for polygons ;-)

> I would suggest looking at the code, contacting J. Franks 
> if there are questions or a need for license clarification or 
> authorization, and finding an alternative algorithm if necessary.

The algorithms are probably public-domain, but we might need a
clean-room implementation :-(

			regards, tom lane