CODEWITHSUNDEEP
c#
Dan
Dan

Reputation: 10538

Calling function in response to network code

I was wondering, how can I avoid a giant switch statement when trying to handle code received from a network source? The message comes in with an opcode (int), with the function to be called depending on aforementioned opcode (not my design, and I can't influence it).

I need to call a function in response to the opcode, but I don't necessarily want to have to hard-code the opcode to function mapping using a switch statement, because that would make it rigid and hard to fix if the network schema changes.

tldr how can I tie an int to a function - noting that the functions may be distributed across the entire solution (each message may require different state information/may belong to a different class) Right now I have marked functions with attributes, but is there a better way of doing this?

Upvotes: 3

Views: 68

Answers (3)

poy
poy

Reputation: 10507

There are definately a few different ways to handle it... However, as usually, the hard-code will actually provide the FASTEST output.

But, if you can handle a little extra latency (and I definately mean a little...) you could try a Dictionary<int, TMessage>.

I would recommend that the type TMessage have a method that would be able to read it's self in. Meaning the code would first read the "op code", use it to pick out the TMessage, and then have the message read the rest in.

If you wanted to get fancy... you could use reflection to populate the dictionary, so you don't have to hardcode ANYTHING.

Upvotes: 0

Dirk
Dirk

Reputation: 10958

Assuming all your functions have the same signature MyFunctionDelegate you can use a Dictionary<int, MyFunctionDelegate> which maps ints to the methods.

If the opcodes range from 0 to N with no gap you can also use a simple array or list.

Upvotes: 1

Sean
Sean

Reputation: 62482

Use a Dictionary to map the int to a handler:

var handlers=new Dictionary<int,Action<NetworkData>>();
handlers[Opcode.Foo]=HandleFoo;
handlers[Opcode.Bar]=HandleBar;

void HandleFoo(NetworkData data)
{
  // Whatever
}

void HandleBar(NetworkData data)
{
  // Whatever
}

Upvotes: 3

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