[IGSTK-Developers] Re: SerialCommunicationSimulator data file format

[Hee-su Kim]

Hi David:

You're right.

I know it doesn't support the binary stream yet.

I planned to use the number of bytes in the stream file but I missed the 
point with the std::string.

I'll go to a VTK course in this week, so I'll make modification next week or 
you can do that in this week.

Another issue is how to treat different responses with the same request.

One option is to maintain a list of different responses for each request. 
Responses could be returned sequentially.

Regards,
Hee-Su

----- Original Message ----- 
From: "David Gobbi" <dgobbi at atamai.com>
To: "Hee-su Kim" <hkim at isis.imac.georgetown.edu>
Cc: "IGSTK-developers" <igstk-developers at public.kitware.com>
Sent: Tuesday, July 19, 2005 7:58 PM
Subject: SerialCommunicationSimulator data file format


> Hi Hee-Su,
>
> I've taken a look at the simulator data file and it the 
> SerialCommunicationSimulator and it misses one of the requirements: it 
> isn't able to handle binary data streams.
>
> The difference between an ASCII data stream and a binary data stream is 
> that the bytes in an ASCII stream only contains ASCII characters, that is, 
> the byte values are always in the range [1,127].
>
> The bytes in a binary stream can have any value in the range [0,255].  A 
> binary stream can contain zeros, but an ASCII stream cannot.
> A chunk of binary data cannot be stored in a C++ string, because a C++ 
> string cannot contain a zero byte, except at the very end.
>
> The reason that this is important is that virtually all tracking systems 
> do at least some communication using binary data, for example we cannot 
> support the Aurora's BX "binary transform" command unless we can 
> communicate with binary data, and tracking systems like the Flock of Birds 
> always communicate transforms with binary data.
>
> In summary:
>
> The Communication classes cannot store their input or data in C++ strings. 
> The data must either be stored in a char array e.g. char data[1024], or in 
> a C++ vector.  Or perhaps, going along with Luis' philosophy on these 
> things, we should define our own data container type for this purpose.
>
> The file format for the CommunicationSimulator data file will also have to 
> be adjusted, because it doesn't support binary data either.  On my wiki 
> design page for SerialCommunicationSimulator I specified a file format 
> that stored the number of bytes used by every sent and received data 
> record, but the file format used by the simulator doesn't appear to follow 
> that design.
>
> - David
>