Re: Proposed replacement for 14.4 and C6.2 (interchange encodings)
Dima (Dmitry Nadezhin) replied to my post:
> 1) This text uses the word Endianess, but without definition.
> We might imagine four mappings of binary64 bits into a sequence of bytes:
We can add "Endianness" to the glossary in Chapter 2:
Endianness denotes one of two common byte orders for common multibyte
objects such as integers or IEEE 754-2008 formats, called Big-Endian
and Little-Endian. (There used to be a greater variety of byte orders,
but for 754 formats the world appears to have settled on just two.)
So I think we can avoid the complication of other permutations. By the
way, bit numbering is ALSO suspect without further information!
> 2) There are still other useful encodings that are not defined by
> this header. For example, it is possible to write vector of
> length L of infsup_b64 decorated intervals.
The signature is NOT A HEADER! It can be a component of a header, and
it is thus useful for it to have a standard representation from which
relevant platform-dependent parameters can be derived. Applications
typically need to know much more about the structure of imported data,
but that knowledge is APPLICATION-specific. The intent of the signature
is simply to capture PLATFORM dependencies.
> 3) There may be a lot of header defined encodings,
See above.
I also realised that whether an application exports decorated or bare
intervals is also an application property, and therefore need not be
encoded in the signature. What we can add to my description is that
the same signature can also be used to describe bare intervals, which
can indeed be useful in bulk interchange.
This also gives an application the opportunity to export an array of
bare intervals followed by an array of decorations. How it describes
this arrangement is not our business, but we can make sure that such a
description can be understood universally across different platforms.
> 4) There is a contention about level 4 encoding.
That's precisely what I'm trying to resolve.
Michel.
---Sent: 2014-06-22 22:07:00 UTC