Re: [Cbor] draft-ietf-cbor-network-addresses: tag validity; deterministic encoding

[Brian E Carpenter <[e-mail]>]

I've fixed the code, run some unit tests and exercised it thoroughly in my GRASP app, and separated the code out as https://github.com/becarpenter/graspy/blob/master/tag5254.py. It's under a BSD licence if anyone is interested.

Is there a generic place for small items of CBOR-related code? This doesn't seem to deserve a repo on its own.

Regards
    Brian
On 03-Nov-21 17:07, Brian E Carpenter wrote:
> On 15-Oct-21 17:50, Carsten Bormann wrote:
>> On 15. Oct 2021, at 06:35, Brian E Carpenter <[e-mail]> wrote:
>>>
>>> So, my ugly code is in the functions build5254() and detag5254() in https://github.com/becarpenter/graspy/blob/master/pfxm4.py
>>
>> Nice.
>>
>> After line 122, there needs to be the Python equivalent of a
>>
>> prefix.sub!(/\x00*\z/, ‘’)
> 
> 
> I took an executive decision to throw an exception for covert bits, rather than silently zero them, and in fact changed all my error returns to ValueError exceptions. I believe that's more Pythonesque.
>    
>> (Why not mix floating point calculations and a regex in the same five lines of code :-)
> 
> Because it makes my head hurt, that's why not.
>>
>> Before line 146, you’d need to check whether the size really is
> `asize`.
> 
> Yes, or that the type really is 'bytes' since Python won't check that for
> me.
> 
>> I think the while loop in 154 needs to be before 151.
> 
> I don't think it matters. Either way, the zero bytes get concatenated.
>    
>> If v[0] == 128 and prefix is 16 bytes, what does prefix[v[0]//8] yield in Python?
> 
> IndexError: index out of range
> 
> Good catch. In my app, that is a case that would never happen.
> 
> I've fixed my code, but will let my test app run for a few hours before 
I
> post the update to github.
> 
>      Brian
> 
> 
>