Re: [Cbor] [netmod] CBOR YANG encoding of union & bits [draft-ietf-core-yang-cbor-12]

[Kio Smallwood <[e-mail]>]

Hi Carsten, 

Yes I agree, requiring an array makes more sense. I would prefer a byte
offset instead of a bit offset then you don't need to worry about the
divisible by eight constraint. 

Therefore the specification would be: 

- A tagged array containing: 

- An unsigned integer byte offset 

- followed by one or more contiguous bytes containing set bits 

- the next offset (must be strictly larger than the offset + length of
previous data item) 

- the next byte(s) 

- etc. 

e.g. 

2020([0, h'0107', 500000000, h'15']) 

The following example should result in an error: 

2020([0, h'0107', 1, h'01']) 

A case should be made that each offset+byte pair should have at least
one set bit. So this would be a valid bitfield that's all zeros: 

2020([]) 

Cheers, 

Kio 

On 2020-05-08 7:48, Carsten Bormann wrote:

> If we go for this, as I'm proposing in <https://mailarchive.ietf.org/arch/msg/netmod/hRMjLIIpOyTNtmkv4yd3gyjd_gA>:
> 
> I think we should require that
> 
> -- the offsets are (unsigned and) divisible by 8;
> -- the byte strings do not overlap.
> 
> I'm also not sure we wouldn't want to require the offset/bitstring pairs to be in order, which would need an array instead of a map (as maps are not ordered).
> 
> Grüße, Carsten