DDSI-RTPS 2.6 RTF Avatar
  1. OMG Issue

DDSIRTP26 — Inconsistent notation used to represent bit positions pictorially

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  • Key: DDSIRTP26-4
  • Status: open  
  • Source: Real-Time Innovations ( Dr. Gerardo Pardo-Castellote, Ph.D.)
  • Summary:

    The spec uses two numbering schemes for bits:

    For example 9.4.1 (Overall Structure)

    0...2...........7...............15.............23. .............31
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

    But then in 9.4.4 (Mapping of the RTPS Header)

    0...2...........8...............16.............24.............. 32
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

    It should be consistent. The more correct scheme appears to be:

    0...2...........8...............16.............24. .............32 
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

    With this scheme the number represents the number of bits that appear before the number (the "." positions). The other scheme seems inconsistent. "0" is placed ahead of the bit of that order, but '7' and the rest are placed after.
  • Reported: DDSI-RTPS 2.5 — Thu, 10 Jun 2021 22:20 GMT
  • Updated: Tue, 15 Nov 2022 22:10 GMT