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TIFF and LibTiff Mail List Archive

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2001.09.08 20:43 "workaround for TIFF file limit size ?", by
2001.09.10 15:28 "Re: workaround for TIFF file limit size ?", by Joel Schumacher

2001.09.10 15:28 "Re: workaround for TIFF file limit size ?", by Joel Schumacher

Does anyone know a workaround for TIFF file limit size of 4 GB (Tiff compression is not useful for me)? A patch for libtiff? Another tiff library? Other tip?

Probably the reason for a 4GB limit is that Tiff files have 32-bit pointers to places within the file. And the limits of a 32-bit number are 4,294,967,295.

I suppose the quickest approach would be to make yourself a 64-bit pointer and adjust libtiff to handle that. Probably need to define your own 64-bit data type also, because I'm pretty sure some of the tag values will probably need more room if you go beyond 4gb also.

But at that point, it really doesn't become a TIFF anymore - at least not something anything else will read. This is a fundamentally different change than, say, adding your own new compression type in the TIFF wrapper. That's something some viewer might not be able to handle and can report that. But what you're proposing is changing the TIFF wrapper itself, making it unrecognizable as a TIFF file. Or causing unpredictable results because the viewer is only looking at half the address pointer.

So I kind of have to question the point of trying to use TIFF or modify libtiff. Especially when you say TIFF compression isn't useful for you.

Using a standard format would be best, but if you can't find one, why not compress it how you want to and store it in some new format of your own creation?

______________________________________________________________________
Joel Schumacher                    JCPenney Co. - UNIX Network Systems
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