DIS7 - SetDataPdu - Access to _variableDatums

[quonn77]

How can I access to the raw data inside the variable datum? Looking at the code I am a little confused. I mean SetDataPdu contains a std::vector<VariableDatum> and I can access to it but inside the VariableDatum I found the following

 /** Type of variable datum to be transmitted. 32 bit enumeration defined in EBV */
  unsigned int _variableDatumID; 

  /** Length, in bits, of the variable datum. */
  unsigned int _variableDatumLength; 

  /** Variable datum. This can be any number of bits long, depending on the datum. */
  unsigned int _variableDatumBits; 

  /** padding to put the record on a 64 bit boundary */
  unsigned int _padding; 

  // Variable Data
  std::vector<EightByteChunk> _variableDatums;

Looking on the standard, AFAIK or let me say as far as I understand, I don't see reference to EightByteChunk _variableDatums even if you marshal and unmarshall it, but no accessor method are provided.... Am I missing something? How does it is supposed to be used? For Java impl a getVariableData method exist, here (c++) how can I access the same data?

Also the getMarshalledSize seems to be wrong.

C++ looks like:

marshalSize = marshalSize + 4;  // _variableDatumID
marshalSize = marshalSize + 4;  // _variableDatumLength
marshalSize = marshalSize + 4;  // _variableDatumBits
marshalSize = marshalSize + 4;  // _padding

Java looks like:

marshalSize = marshalSize + 4;  // variableDatumID
marshalSize = marshalSize + 4;  // variableDatumLength
marshalSize = marshalSize + payload.length; // payload length
marshalSize = marshalSize + padding.length; // padding

For c++ seems we can add only 4 bytes.... Regards

[quonn77]

I would like to inform that I am working on a fork trying to fix those issues I found with DIS7. When I will be ready i will ask for a merge request.

[leif81]

@quonn77 I think you're on the right track. Quite a bit of work was done to improve the Java and C++ language implementations, but this may be one of those cases where an improvement was done in one language and not the other yet. If that's the case here, I suggest trying to backport the change done to the Java SetDataPdu into the C++ SetDataPdu. And yes a pull request would be very welcome!

It seems like you've found your way around already, but for my own sake I'll leave a few links here as references.

1. The C++ SetDataPdu class - https://github.com/open-dis/open-dis-cpp/blob/master/src/dis6/SetDataPdu.cpp
2. The Java SetDataPdu class - https://github.com/open-dis/open-dis-java/blob/master/src/main/java/edu/nps/moves/dis/SetDataPdu.java
3. The Java SetDataPdu unit test - https://github.com/open-dis/open-dis-java/blob/master/src/test/java/edu/nps/moves/dis/SetDataPduTest.java

[quonn77]

@leif81 I will take definitively a look into it, I am working on a fork repo to fix those issues. So as soon I have terminated the development I will get in touch with you to let review my changes.

[quonn77]

@leif81 I would just like to inform you, that I have started again to work on the Open-dis-cpp about aligning the DIS7 PDU with the IEEE Std 1278.1-2012 specification. I have switched, until now, to another project so sorry for the late delay. I have some working code for the SetData, StartResume and StopFreeze Pdu, as soon as I will do some code cleanup i will share my work on the forked repo