2004.09.17 15:55 "RE: [Tiff] BigTIFF Tag Value Count issue", by Fernando Loygorri

Some possible implementation languages do not even support unsigned types.

That's what I meant: Java is one of them.

Is there an alternative to using unsigned 64-bit values to access large data?

There is a standard class, BigInteger, that is of arbitrary size. Unfortunately, using objects like BigInteger instead of primitives like long is slower and clumsier.

By using unsigned 64-bit values in BigTIFF instead of unsigned 32-bit values in TIFF, we increase the range by a factor of 2^32.

By using signed 64-bit values in BigTIFF, which are equivalent to unsigned 63-bit values, the range would increase by a factor of 2^31, still a very respectable value.

Just to clarify, I'm not proposing that negative 64-bit values should have any meaning. They should be outlawed by the spec. I'm proposing that the spec outlaw values with the most-significant bit set, and this only to accommodate languages like Java that have a 64-bit signed type but no 64-bit unsigned type.

Regards,

FGL