la putain

#pragma once
#include <stdint.h>
#include <Windows.h>

namespace asmjs
{
    class VMTHook
    {
        static int Unprotect(void* region)
        {
            MEMORY_BASIC_INFORMATION mbi;
            VirtualQuery((LPCVOID)region, &mbi, sizeof(mbi));
            VirtualProtect(mbi.BaseAddress, mbi.RegionSize, PAGE_READWRITE, &mbi.Protect);
            return mbi.Protect;
        }

        static void Protect(void* region, int protection)
        {
            MEMORY_BASIC_INFORMATION mbi;
            VirtualQuery((LPCVOID)region, &mbi, sizeof(mbi));
            VirtualProtect(mbi.BaseAddress, mbi.RegionSize, protection, &mbi.Protect);
        }

        public:

        /*
        * pObjectInstance: pointer to an pObjectInstance of a class
        * hookFn: function to overwrite with
        * methodOffset: 0 = method 1, 1 = method 2 etc...
        * return: original function
        */

        static void* Install(void* pObjectInstance, void* hookFn, int methodOffset)
        {
            intptr_t vtable = *((intptr_t*)pObjectInstance);
            intptr_t entry = vtable + sizeof(intptr_t) * methodOffset;
            intptr_t original = *((intptr_t*)entry);

            int originalProtection = Unprotect((void*)entry);
            *((intptr_t*)entry) = (intptr_t)hookFn;
            Protect((void*)entry, originalProtection);

            return (void*)original;
        }
    };
}