Codechange: [WIN32] Add a wrapper around GetProcAddress()

src/os/windows/win32.h

@@ -13,8 +13,47 @@
 #include <windows.h>
 bool MyShowCursor(bool show, bool toggle = false);
 
-typedef void (*Function)(int);
-bool LoadLibraryList(Function proc[], const char *dll);
+class DllLoader {
+public:
+	explicit DllLoader(LPCTSTR filename)
+	{
+		this->hmodule = ::LoadLibrary(filename);
+		if (this->hmodule == nullptr) this->success = false;
+	}
+
+
+	~DllLoader()
+	{
+		::FreeLibrary(this->hmodule);
+	}
+
+	bool Success() { return this->success; }
+
+	class ProcAddress {
+	public:
+		explicit ProcAddress(void *p) : p(p) {}
+
+		template <typename T, typename = std::enable_if_t<std::is_function_v<T>>>
+		operator T *() const
+		{
+			return reinterpret_cast<T *>(this->p);
+		}
+
+	private:
+		void *p;
+	};
+
+	ProcAddress GetProcAddress(const char *proc_name)
+	{
+		void *p = reinterpret_cast<void *>(::GetProcAddress(this->hmodule, proc_name));
+		if (p == nullptr) this->success = false;
+		return ProcAddress(p);
+	}
+
+private:
+	HMODULE hmodule = nullptr;
+	bool success = true;
+};
 
 char *convert_from_fs(const wchar_t *name, char *utf8_buf, size_t buflen);
 wchar_t *convert_to_fs(const char *name, wchar_t *utf16_buf, size_t buflen);