AWARE SYSTEMS
TIFF and LibTiff Mail List Archive

Thread

2012.05.18 13:23 "[Tiff] TIFFGetField: count should be uint32_t (Bug in documentation)", by Sandro Mani
2012.05.18 14:27 "Re: [Tiff] TIFFGetField: count should be uint32_t (Bug in documentation)", by Bob Friesenhahn
2012.06.27 15:12 "[Tiff] variable sized tags and passcount", by David Hoese

2012.05.18 14:27 "Re: [Tiff] TIFFGetField: count should be uint32_t (Bug in documentation)", by Bob Friesenhahn

according to [1], when querying multi-valued fields with TiffGetField, count should be of a 16-bit unsigned integer. However, in various places in the source libtiff source code, a 32-bit unsigned integer is used. Indeed, a nasty bug I encountered was caused by count being 16 bits wide:

[ stuff removed ]

If my analysis is correct, I guess the documentation should be fixed.

I believe that your analysis must be correct. In my own application code, the working support for "unsupported" tags does pass a uint32 pointer for the 'count' field.

The interface is definitely confusing. Supported tags use different/varying interface definitions.

Bob
--
Bob Friesenhahn
bfriesen@simple.dallas.tx.us, http://www.simplesystems.org/users/bfriesen/
GraphicsMagick Maintainer, http://www.GraphicsMagick.org/