[csharp] use IDirectBuffer implementation from Agrona.NET

[bpb1]

It would be nice if Aeron.NET and the generated c# from sbe referred to the same IDirectBuffer interface. I guess this is dependent on AdaptiveConsulting/Aeron.NET#57

[mjpt777]

@JPWatson Should anything be done on this?

[swimtver]

Hello,
Do you have any plans to implement it?
Or could you give me some tips how properly manipulate bytes from Agrona IDirectBuffer to DirectBuffer from this package.

Thanks for advance.

[mjpt777]

@swimtver I hear that @JPWatson plans to push a C# generator that uses this.

[JPWatson]

Yes, I have been working on it. We've got an early stage generator for SBE that uses .NET implementation of Agrona.

For the time being, there is a workaround. You can use the pointers to wrap the same underlying memory.

public static unsafe void Wrap(this DirectBuffer target, UnsafeBuffer source, int length)
{
   target.Wrap((byte*) source.BufferPointer.ToPointer(), length);
}

[swimtver]

@mjpt777 , @JPWatson thank you very much!

[juddgaddie]

@JPWatson Any update on how you are getting along with this?

[JPWatson]

We have been incubating a generator that mirrors the Java generator and uses the Agrona.NET interfaces. Would be happy to share that if you're interested?

[juddgaddie]

That would be much appreciated.

[JPWatson]

@juddgaddie Feel free to have a place around with this:
https://github.com/JPWatson/sbe-generators

[JPWatson]

Eventually, I hope to get this into the main repository once it has some tests around it.

[JPWatson]

I also use this generator in Aeron.NET to generate the Archive/Cluster codecs.
https://github.com/AdaptiveConsulting/Aeron.NET/blob/master/scripts/generate-archive-codecs.bat

Source for this build of the JAR is here:
https://github.com/JPWatson/simple-binary-encoding/commits/csharp-update

[juddgaddie]

Thanks for sharing, @JPWatson which version of CSharpGenerator is more up to date https://github.com/JPWatson/sbe-generators or https://github.com/JPWatson/simple-binary-encoding/commits/csharp-update ?

[JPWatson]

AFAIR there isn't any difference between the generators themselves.

[juddgaddie]

@JPWatson is the bounds checking not implemented simply because you didn't get around to it or is there any technical reason?

[JPWatson]

@juddgaddie There is bound checking code in UnsafeBuffer but it's set at compile time rather than runtime. From what I remember, there just wasn't an obvious way to mirror the same behaviour as the java version.

[juddgaddie]

Like Java, C# (unlike c/c++) is typically not compiled from sources for that reason I think the bounds checking would be better served with a runtime toggle we could use system environment variables (the same approach as c or c++ code uses for runtime configuration)

I also would think the default build that goes to Nuget should have bounds checking enabled by default.
@JPWatson thoughts ?

Happy to send PRs

[juddgaddie]

@JPWatson Example of what I mean here: https://gist.github.com/juddgaddie/eeafbbb195a332bf72808748cdcd4336