UDP data + circular buffer

jsulm

@Chanchan You will need to implement the circular buffer by yourself or find existing one. As far as I know Qt does not have such a container.

J.Hilk

@jsulm actually, I quick google search resulted in this surprise class

https://doc.qt.io/archives/qt-5.5/qt3d-qcircularbuffer.html#details

it's part of qt3d, which would explain, why I haven't heard of it before.

jsulm

@J.Hilk Yes, I saw it.
But I'm not sure why it is part of Qt3D module?! And is it still there in recent versions?

Chanchan

@J.Hilk
Yes I saw this page, I tried to implement it to my example but I didn't succeed :/

J.Hilk

@jsulm said in UDP data + circular buffer:

And is it still there in recent versions

that's a god point, I can't find it in the 5.12 docs. Therefore I don't think so ?

Anyway a basic circular buff is like 40 lines. One should be able to do create on fairly easily with based on e.g. QVector.

Chanchan

Ok, I will try found it and integrate to my code
I have another problem but I prefer to open another thread for it ^^
Thank you :)

Kent-Dorfman

Ring buffers are only applicable in specialized situations where you need a container of constant memory footprint and quick deque access of elements (such as hardware device I/O. I can see such a thing being in the 3d graphics modules, but its utility in the general framework is very limited. The buffering of incoming UDP is such a case where its utility is valid. There are many online references describing how to implement the ring buffer container.

EDIT: a gotcha that the op needs to be aware of is that you CANNOT create a ring buffer of n characters and expect to access sequences of those characters. each element must be explicitly accessed as a single operation. The reason is that when the head/tail loops back to element n[0] the sequence of characters is no longer contiguous.

aha_1980

@Chanchan and @J-Hilk: I might be wrong, but isn't QQueue exactly what you want?

aha_1980

@jsulm said in UDP data + circular buffer:

@Chanchan You will need to implement the circular buffer by yourself or find existing one. As far as I know Qt does not have such a container.

As said above, there is QQueue.

J.Hilk

@aha_1980 It's probably a better starting point, but the QQueue is not limited in size -> No circular buffer, right?

aha_1980

@J.Hilk said in UDP data + circular buffer:

QQueue is not limited in size

Correct. If you need this behavior, you have to check size() before enqueue().

Chanchan

Actually my case is :
I receive a lot of UDP data, I have to implement a process function to transfert these data to the good function, this function will implement datas, etc...
For this I need a circular buffer, I will take a look on your tips, thank you :)