[Cbor] Simple values 24..31 (was Re: List of not-well-formed CBOR and test vectors)

Laurence Lundblade <lgl@island-resort.com> Thu, 01 August 2019 03:01 UTC

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From: Laurence Lundblade <lgl@island-resort.com>
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Subject: [Cbor] Simple values 24..31 (was Re: List of not-well-formed CBOR and test vectors)
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On Jul 30, 2019, at 2:23 AM, Carsten Bormann <cabo@tzi.org>; wrote:
> 
> Why are you testing only 25 of the 32 impermissible SIMPLE cases?

Because I’m confused about unassigned vs reserved in this table (just realized I was confused):

                       +---------+-----------------+
                       | Value   | Semantics       |
                       +---------+-----------------+
                       | 0..19   | (Unassigned)    |
                       |         |                 |
                       | 20      | False           |
                       |         |                 |
                       | 21      | True            |
                       |         |                 |
                       | 22      | Null            |
                       |         |                 |
                       | 23      | Undefined value |
                       |         |                 |
                       | 24..31  | (Reserved)      |
                       |         |                 |
                       | 32..255 | (Unassigned)    |
                       +---------+-----------------+

Neither sections 7.1 nor 9.2 mention 24..31. 

These of course can’t be represented by the single byte 0xf8 through 0xff because those are float and such, but there seems to be no trouble representing the with 0xf8 0x18 through 0xf8 0x1f.

Why wouldn’t 24 through 255 be considered unassigned and encoded 0xf8 0x18 through 0xf8 0xff?

LL