Implement il2cpp initialize method

lib/src/il2cpp-init.cpp

@@ -0,0 +1,45 @@
+#include "pch.h"
+
+#include "il2cpp-init.h"
+
+#define DO_API(r, n, p) r (*n) p
+#include "il2cpp-api-functions.h"
+#undef DO_API
+
+#define DO_APP_FUNC(a, r, n, p) r (*n) p
+namespace Genshin {
+#include "il2cpp-functions.h"
+}
+#undef DO_APP_FUNC
+
+using std::string;
+
+ull GetAddressByExports(HMODULE base, const char* name) {
+	ull funcAddr = reinterpret_cast<ull>(GetProcAddress(base, name));
+	return funcAddr == 0 ? 0 : funcAddr;
+}
+
+ull milliseconds_now() {
+	static LARGE_INTEGER s_frequency;
+	static BOOL s_use_qpc = QueryPerformanceFrequency(&s_frequency);
+	if (s_use_qpc) {
+		LARGE_INTEGER now;
+		QueryPerformanceCounter(&now);
+		return (1000LL * now.QuadPart) / s_frequency.QuadPart;
+	} else {
+		return GetTickCount64();
+	}
+}
+
+void InitIL2CPP() {
+	auto start = milliseconds_now();
+	auto hBase = GetModuleHandle("UserAssembly.dll");
+	auto bAddr = (ull)hBase;
+	#define DO_API(r, n, p) n = (r (*) p) GetAddressByExports(hBase, #n);
+	#include "il2cpp-api-functions.h"
+	#undef DO_API
+	#define DO_APP_FUNC(a, r, n, p) n = (r (*) p)(bAddr + a)
+	#include "il2cpp-functions.h"
+	#undef DO_APP_FUNC
+	printf("Initialized in %llu ms.\n", milliseconds_now() - start);
+}