Initial public release of rem-essentials

2026-08-11 16:48:50 +02:00
commit d611924a5e
161 changed files with 9792 additions and 0 deletions
@@ -0,0 +1,76 @@
+#pragma once
+
+#include <windows.h>
+
+#include <cassert>
+#include <cstring>
+#include <initializer_list>
+
+namespace rem
+{
+    void Patch(DWORD address, const void* data, UINT length);
+    void PatchBytes(DWORD address, std::initializer_list<BYTE> bytes);
+    void Nop(DWORD address, UINT length);
+    void ReadWriteProtect(DWORD address, DWORD size);
+
+    template <typename Type>
+    inline void Patch(DWORD address, Type value)
+    {
+        Patch(address, &value, sizeof(Type));
+    }
+
+    template <typename Type>
+    inline Type& ValueAt(DWORD address)
+    {
+        ReadWriteProtect(address, sizeof(Type));
+        return *reinterpret_cast<Type*>(address);
+    }
+
+    template <typename Func>
+    inline Func FunctionAt(DWORD address)
+    {
+        return reinterpret_cast<Func>(address);
+    }
+
+    template <typename Func>
+    Func SetRelPointer(DWORD location, Func hook)
+    {
+        DWORD& relative = ValueAt<DWORD>(location);
+        DWORD original = location + relative + 4;
+        DWORD hookAddress = *reinterpret_cast<DWORD*>(&hook);
+        relative = hookAddress - (location + 4);
+        return FunctionAt<Func>(original);
+    }
+
+    template <typename Func>
+    void Hook(DWORD address, Func hook, UINT instructionLength, bool jump = false)
+    {
+        assert(instructionLength >= 5);
+        Patch<BYTE>(address, jump ? 0xE9 : 0xE8);
+        SetRelPointer(address + 1, hook);
+
+        if (instructionLength > 5)
+            Nop(address + 5, instructionLength - 5);
+    }
+
+    template <typename Func>
+    Func Trampoline(DWORD address, Func hook, UINT instructionLength)
+    {
+        BYTE* gateway = static_cast<BYTE*>(
+            VirtualAlloc(nullptr, instructionLength + 5, MEM_COMMIT | MEM_RESERVE, PAGE_EXECUTE_READWRITE));
+
+        ReadWriteProtect(address, instructionLength);
+        memcpy(gateway, reinterpret_cast<void*>(address), instructionLength);
+
+        Hook(address, hook, instructionLength, true);
+        Hook(reinterpret_cast<DWORD>(gateway + instructionLength), FunctionAt<Func>(address + instructionLength), 5, true);
+
+        return FunctionAt<Func>(reinterpret_cast<DWORD>(gateway));
+    }
+
+    template <typename Func>
+    void CleanupTrampoline(Func trampoline)
+    {
+        VirtualFree(reinterpret_cast<void*>(*reinterpret_cast<DWORD*>(&trampoline)), 0, MEM_RELEASE);
+    }
+}