Question

In the game I’m making, I nee to be able to send std::vectors of integer over a network.

A packet seems to be made up entirely of a string. Since enet, the network libray im using takes care of endian, my first idea on solving this is to send a messsage where the first byte is the message id, as usual, the next 4 bytes would be an integer indicating the length of the array, and all subsequent bytes would be the ints in the array. On the client side I can then push these back into a vector.

Is this how it is usually done or am I missing something critical? Is there a better way to do it?

Thanks

Answer 1

In general, there are two approaches to solving this problem which can be combined. One is to put the length of the array before the actual array. The other involves including some framing to mark the end (or beginning) of your message. There are advantages and disadvantages to each.

Putting the length before the array is simplest. However, if there should ever be a bug where the length does not match the number of integers, there is no way to detect this or recover from it.

Using a framing byte(s) to mark the end of the message has the advantage of more robustness and the ability to recover from an improperly formatted message at the cost of complexity. The complexity comes in the fact that if your framing bytes appear in your array of integers, you must escape the bytes (i.e. prepend and escape character). Also, your code to read messages from the network becomes a little more complicated.

Of course, this all assumes that you are dealing stream and not a datagram. If your messages are clearly packetized already, then the length should be enough.