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Game Development

boost::bind and boost::function for RPC

Based on forum suggestions I’m looking into boost::bind and boost::function to do RPC calls rather than my current assembly code based system.

I may be misunderstanding what it does, but I believe that boost::function is a way to store function pointers (regular or object member). And boost::bind allows you to bind parameters to function pointers. Using templates, you can pass complex object types on the stack. My existing assembly implementation can only pass simple structures.

If I’m correct, I can do something like this:

void DoSomething(MyObject myObject) {…}
Call(“DoSomething”, myObject);
(On the remote system)
boost::function ptrToDoSomething;
(use boost::bind to bind a stack based instance of MyObject to DoSomething)
(Somehow call DoSomething)

I’m a bit vague on the details now but if it works it will compile out to what is essentially a native function call.

Another problem with my existing implementation of RPC is I am using memcpy for the parameter list. This won’t work with complex types that have custom serialization – even including strings. But by overloading < < and >> I can add support for this.

Normal types get a general template.

template <class templateType>
BitStream& operator<<(BitStream& out, const templateType& c)
{
out.Write(c);
return out;
}
template <class templateType>
BitStream& operator>>(BitStream& in, templateType& c)
{
bool success = in.Read(c);
assert(success);
return in;
}

The user can then overload types for a particular class, just replace tempateType with the name of the relevant class.

If this all works out I will finally have the ultimate implementation of RPC calls.

1. Works with C functions and object member functions, including those that use multiple inheritance, with an arbitrary inheritance order
2. Can pass types that use complex serialization (such as my string compression).
3. Can call functions that take complex types in the parameter list, types that cannot fit in a single register.
4. I think I can even do automatic object pointer lookups within parameter lists

In other words, the ability to call any authorized function on a remote system, using any type of parameter, including referenced pointers, with any type of data. Pretty exciting 🙂

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