HLE DSP: Implement AAC audio decoder

include/audio/aac_decoder.hpp

@@ -0,0 +1,24 @@
+#pragma once
+#include <functional>
+
+#include "audio/aac.hpp"
+#include "helpers.hpp"
+
+struct AAC_DECODER_INSTANCE;
+
+namespace Audio::AAC {
+	class Decoder {
+		using DecoderHandle = AAC_DECODER_INSTANCE*;
+		using PaddrCallback = std::function<u8*(u32)>;
+
+		DecoderHandle decoderHandle = nullptr;
+
+		bool isInitialized() { return decoderHandle != nullptr; }
+		void initialize();
+
+	  public:
+		// Decode function. Takes in a reference to the AAC response & request, and a callback for paddr -> pointer conversions
+		void decode(AAC::Message& response, const AAC::Message& request, PaddrCallback paddrCallback);
+		~Decoder();
+	};
+}  // namespace Audio::AAC