Detour and Generic Hook Class

MS Detours lacks OOP, so this wraps and manages a detour. You could also derive from the IHook class and define your own hooking mechanisms or use different libraries. MS Detours can be found at https://github.com/microsoft/Detours

Usage:

Suppose you want to hook a function with the signature int foo(Object* object, int count) located at address void* Target.

IMPORTANT PREFACE: When constructing a Detour (or any IHook) object with a lambda, you must leave the capture clause (the [] at the beginning of a lambda) empty. This prevents it from becoming a context-dependent std::function. I'll eventually get around to making a formal template constraint.

Replacement

To replace the original function, do something like this:

		 Detour<int, Object*, int> a_detour(Target, [](Object* object, int count){
						 ... code
						 return 20; //dummy value
		 });

Because it returns to the original function's caller, the original function is effectively replaced.

Detour/Hook

To call the original function at any point, do:

static_cast<int(__fastcall*)(Object*, int)>(a_detour.GetTarget())(object, count)

within your hook function. Do it before your code, return it as a closure, throw it in the middle, whatever you want.