Re: [Cbor] Self Described CBOR - Little Endian

Carsten Bormann <cabo@tzi.org> Wed, 24 March 2021 20:27 UTC

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From: Carsten Bormann <cabo@tzi.org>
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Date: Wed, 24 Mar 2021 21:27:01 +0100
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To: Joe Hildebrand <hildjj@cursive.net>
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Subject: Re: [Cbor] Self Described CBOR - Little Endian
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On 2021-03-24, at 21:09, Joe Hildebrand <hildjj@cursive.net> wrote:
> 
> The `s390x/node` docker image emulates big endian (slowly), and includes Perl 5.24.1
> 
> I test with "docker run --rm -it -v ${PWD}:/root/cbor -w /root/cbor s390x/node npm test”

I used to have an iBook (PowerPC CPU, run as big-endian) set up as a CI system…

But to answer the original question, CBOR is big-endian because IETF protocols generally are.  Creating a little-endian fork of CBOR wouldn’t really help that much.  (Turns out my (endian-independent) code is usually shorter for big-endian transfer than it is for little-endian — remember that you'll have to byte-shift the numbers anyway to maintain alignment on the decoded side, so it’s not that much more effort to arrange them.)  And it would hurt a lot; even with a magic number in front of it (see [1] for our current view of how magic numbers for CBOR-based file encodings should look like).

Grüße, Carsten

[1]: https://www.ietf.org/archive/id/draft-ietf-cbor-file-magic-00.html