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[Cbor] Re: Early allocation for packed CBOR (Re: Reminder: CBOR WG Virtual Meeting on 2024-12-11)

Carsten Bormann <cabo@tzi.org> Wed, 11 December 2024 06:03 UTC

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From: Carsten Bormann <cabo@tzi.org>
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Date: Wed, 11 Dec 2024 07:02:50 +0100
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Subject: [Cbor] Re: Early allocation for packed CBOR (Re: Reminder: CBOR WG Virtual Meeting on 2024-12-11)
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>> What would be the right size then? 250 million?  220 million?
> 
> A typical draft allocating tags allocates a number that you can count on one hand.  Each such tag has a human-readable description of its purpose in the registry so people know what to use them for.

I don’t follow.
The description given in some of our registrations is for a range and is exactly as readable as it would be for a single tag.

> I'd suggest that a reasonable maximum number of tags for a draft to allocate for its purposes is on the order of ten.
> 
> If that's not possible for this draft to achieve that, then I suspect that the draft is somehow abusing the tag mechanism to achieve something other than the normal purpose of tags.

I explained this in a previous message; this is a space-saving device (which of course is doubly appropriate for a packing mechanism).

This approach is just an idiom that has evolved in how tags are being used in CBOR.
Compare RFC 9277 for another example [1].
I don’t think that this way of dealing with the unary (single-content) nature of tags is going away for any reason.

Grüße, Carsten

[1]: https://www.rfc-editor.org/rfc/rfc9277#name-cbor-tags-for-coap-content-

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