2004.05.27 01:15 "[Tiff] large TIFF - two alternatives", by Steve Carlsen
- 2004.05.27 07:30 "Re: [Tiff] large TIFF - two alternatives", by Andrey Kiselev
- 2004.05.27 09:25 "Re: [Tiff] large TIFF - two alternatives", by Rob van den Tillaart
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2004.05.27 10:43 "Re: [Tiff] large TIFF - two alternatives", by John Aldridge
- 2004.05.27 12:49 "Re: [Tiff] large TIFF - two alternatives", by Andrey Kiselev
- 2004.05.27 13:05 "Re: [Tiff] large TIFF - two alternatives", by Frank Warmerdam
- 2004.05.27 18:31 "Re: [Tiff] large TIFF - two alternatives", by Chris Cox
- 2004.06.01 11:50 "Re: [Tiff] large TIFF - two alternatives", by John Aldridge
- 2004.05.27 16:37 "Re: [Tiff] large TIFF - two alternatives", by Frank Warmerdam
- 2004.06.04 13:31 "RE: [Tiff] large TIFF - two alternatives", by Ed Grissom
- 2004.06.09 20:33 "[Tiff] Re: large TIFF - two alternatives", by Steve Carlsen
2004.06.09 20:33 "[Tiff] Re: large TIFF - two alternatives", by Steve Carlsen
It seems like the prevailing opinion is for making "Large TIFF" be mostly just like existing TIFF except for supporting 8-byte addresses.
Making the "Alternative 1" proposal a bit more concrete, then, and adding some 8-byte alignment language and a hook for future expansion:
============================= 8-Byte TIFF =======================
- The ID, in header bytes 2-3, formerly decimal 42, now changes to 0x4242. ( I really like the '42', and this seems like a nice way to have my cake and eat it, too.)
- Header bytes 4-5 contain the decimal number 8. (If there is some other number here, a reader should give up.) (to provide a nice way to move to 16-byte pointers some day.)'
- Header bytes 6-7 are reserved and must be zero. (If they're not, a reader should give up.)
- Header bytes 8-15 contain the 8-byte offset to the 0th IFD.
- Value/Offset fields are 8 bytes long, and take up bytes 8-15 in an IFD entry. (If the value is <= 8 bytes, it must be stored in the field.) (All values must begin at an 8-byte-aligned address.)
- 8-byte offset to the Next_IFD, at the end of an IFD.
- to keep IFD entries 8-byte-aligned, we begin with an 8-byte (instead of 2-byte) count of the number of directory entries.
- add TIFFTypes of LONG8 (= 13), an 8 byte (unsigned) int, and SLONG8 (= 14).
- StripOffsets and TileOffsets and ByteCounts can be LONG8.
- The extension is ".tf8", and the format is called "8-Byte TIFF".
Otherwise, it's just like "original TIFF." ("TIFF Classic?")
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Are we close to general agreement? Am I missing something?
Regards,
Steve Carlsen