2012.10.11 23:04 "Re: [Tiff] TIFFTAG_EXIFIFD tag type change in libTIFF 4.0.x?", by Andrew Pangborn

Without even looking into this issue, I should mention that due to libtiff 4 supporting the new BigTIFF format (supports huge files via 64-bit offsets), offsets are now produced/consumed as 64-bit unsigned types.

Thanks for pointing that out Bob. It looks like our code was already using toff_t for the offset value passed to TIFFSetField for this tag, which is now a uint64, so I think we are okay there.

I agree that a 64-bit offset is required for offsets in a BigTIFF file, but I'm concerned with writing a 32-bit offset for classic tiff.

I found the following in tif_dirwrite.c

    if( TIFFDataWidth(in_datatype) == 8 && !(tif->tif_flags&TIFF_BIGTIFF) )
    {
        if( in_datatype == TIFF_LONG8 )
            datatype = TIFF_LONG;
        else if( in_datatype == TIFF_SLONG8 )
            datatype = TIFF_SLONG;
        else if( in_datatype == TIFF_IFD8 )
            datatype = TIFF_IFD;
        else
            datatype = in_datatype;
    }

I think if I add an additional entry to tif_dirinfo.c with TIFF_LONG8 instead of TIFF_IFD8 it should work for both classic tiff and BigTIFF?

Thanks,
-Andrew