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September 2004
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2004.09.17 06:35 "Re: BigTIFF Tag Value Count issue", by Rob Tillaart
Hi, > That is indeed the case, so there is an extra option. Allow me to resume and > index all three options, then > > Option 0: stick with 4 byte tag count members (alignment, tag data <= 4 gig, > Frank's choice) > Option 1: make it an 8 byte tag count (no alignment, tag data > 4 gig allowed) > Option 2, courtesy of Bob: make it 8 byte tag count, add 4 padding bytes > (alignment, tag data > 4 gig allowed) There is another option to get 8 byte alignment, so instead of 4 padding bytes they are used for extending the first 2 fields => aligning every field to 32 bit. This might be easier to handle by processors [less complex masking] Offset - Datatype - Value -------------------------- 0 - ULONG - Tag identifying code 4 - ULONG - Datatype of tag data 8 - Unsigned Long - Number of values 8 - 4 bytes - Tag data or offset regards, rob