Re: [certi-dev] Problem with VariableLengthData

[Eric Noulard]

2011/6/16 Christoph Laesche <address@hidden>:
> Hi,
>
> I am using several own datatypes which I serialize to a
> VariableLengthData object to transfer it using CERTI (w/ rti1516). I
> noticed that the transfered data does not arrive correctly. The
> VariableLengthData object which I receive in the other federate does not
> have the correct size.
>
> I tracked down the problem and found out that it occurs when the data
> contains a byte of the value 0. It seems as if the problem is the usage
> of string as ParameterValue_t because the .size() call will return the
> string length and therefore will take a 0 byte as an \0, thus ending the
> string (although there is data behind it).

Pretty right we should have something like:
typedef std::vector<char> ParameterValue_t;

(this has to be done for AttributeValue_t as well)
unfortunately doing this unique change in certi.hh
currently leads to multiple compile errors just now.

This is fixable but this require some work inside the message
management of CERTI
because generated files ([N]M_Classes.[hh|cc]) assumes AttributeValue_t
and ParameterValue_t are string.

> Is this a known problem and is there a fix for it?

I guess the string usage is a bad historical habit,
and we all just have been lucky because we did not face this issue [yet]
so basically this is not a known issue :-(.

> How have you serialized your data objects without having a 0 in it?

We don't do anything special, but may be the HLA 1.3 interface does not
exhibit the same issue and we currenlty use it more than the 1516 one.

I guess you may be blocked with this issue.
Are you willing to provide a patch that works for you?

-- 
Erk
Membre de l'April - « promouvoir et défendre le logiciel libre » -
http://www.april.org