Re: [Cbor] Benjamin Kaduk's No Objection on draft-ietf-cbor-network-addresses-09: (with COMMENT)

Michael Richardson <mcr+ietf@sandelman.ca> Thu, 07 October 2021 18:56 UTC

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From: Michael Richardson <mcr+ietf@sandelman.ca>
To: Benjamin Kaduk <kaduk@mit.edu>
cc: Carsten Bormann <cabo@tzi.org>, draft-ietf-cbor-network-addresses@ietf.org, Barry Leiba <barryleiba@computer.org>, cbor@ietf.org, The IESG <iesg@ietf.org>, cbor-chairs@ietf.org
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Date: Thu, 07 Oct 2021 14:55:55 -0400
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Subject: Re: [Cbor] Benjamin Kaduk's No Objection on draft-ietf-cbor-network-addresses-09: (with COMMENT)
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Benjamin Kaduk <kaduk@mit.edu> wrote:
    > On Wed, Oct 06, 2021 at 04:41:40PM -0400, Michael Richardson wrote:
    >>
    >> Carsten Bormann <cabo@tzi.org> wrote:
    >> >> unused_bits = (8 - (prefix_length_in_bits & 7)) % 8;
    >>
    >> > Well, I for one don’t like making the “simply” more complicated (*).
    >>
    >> I have no strong preference.
    >> If I didn't have to read/write C again in my life, that would be fine.

    > I'm sure many share that sentiment :)

okay, so
  unused_bits = (8 - (prefix_length_in_bits % 8);

produces the wrong answer (8) when it's a multiple of 8 and the answer should
be 0.

  unused_bits = (8 - (prefix_length_in_bits % 8) % 8;

gives the right answer.  Can I use that?

--
Michael Richardson <mcr+IETF@sandelman.ca>   . o O ( IPv6 IøT consulting )
           Sandelman Software Works Inc, Ottawa and Worldwide