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Re: [Cbor] CBOR magic number, file format and tags

Josef 'Jeff' Sipek <jeffpc@josefsipek.net> Thu, 21 January 2021 02:19 UTC

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Date: Wed, 20 Jan 2021 21:19:07 -0500
From: Josef 'Jeff' Sipek <jeffpc@josefsipek.net>
To: Michael Richardson <mcr+ietf@sandelman.ca>
Cc: cbor@ietf.org, cose <cose@ietf.org>
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Subject: Re: [Cbor] CBOR magic number, file format and tags
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On Wed, Jan 20, 2021 at 21:11:49 -0500, Michael Richardson wrote:
> 
> Josef 'Jeff' Sipek <jeffpc@josefsipek.net> wrote:
>     > Recently, I was thinking about the fun fact that the Unicode string
>     > "bor" and the byte string "BOR" end up getting encoded as "cbor" and
>     > "CBOR", respectively.
> 
> obiwan-[work/richardson/cbor-file-magic](2.6.6) mcr 10355 %echo -n cbor | cbor2diag.rb
> "bor"
> 
> obiwan-[work/richardson/cbor-file-magic](2.6.6) mcr 10356 %echo -n CBOR | cbor2diag.rb
> h'424F52'

Which is hex for 'B' 'O' 'R'. :)

I'm guessing cbor2diag.rb sees the raw data and hexdumps it to be helpful.
Here's what python has to say:

In [1]: import cbor

In [2]: cbor.loads(b'cbor')
Out[2]: 'bor'

In [3]: cbor.loads(b'CBOR')
Out[3]: b'BOR'

Note the difference in return type - the first is unicode string the second
is a byte string.

Jeff.

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