1 files changed, 61 insertions, 7 deletions

diff --git a/core/os/midi_driver.h b/core/os/midi_driver.h
index cad3d8189e..ddce63f9c8 100644
--- a/core/os/midi_driver.h
+++ b/core/os/midi_driver.h
@@ -42,19 +42,73 @@ class MIDIDriver {
 	static MIDIDriver *singleton;
 	static uint8_t last_received_message;
 
+protected:
+	// Categories of message for parser logic.
+	enum class MessageCategory {
+		Data,
+		Voice,
+		SysExBegin,
+		SystemCommon, // excluding System Exclusive Begin/End
+		SysExEnd,
+		RealTime,
+	};
+
+	// Convert midi data to InputEventMIDI and send it to Input.
+	// p_data_len is the length of the buffer passed at p_data, this must be
+	// at least equal to the data required by the passed message type, but
+	// may be larger. Only the required data will be read.
+	static void send_event(int p_device_index, uint8_t p_status,
+			const uint8_t *p_data = nullptr, size_t p_data_len = 0);
+
+	class Parser {
+	public:
+		Parser() = default;
+		Parser(int p_device_index) :
+				device_index{ p_device_index } {}
+		virtual ~Parser() = default;
+
+		// Push a byte of MIDI stream. Any completed messages will be
+		// forwarded to MIDIDriver::send_event.
+		void parse_fragment(uint8_t p_fragment);
+
+		static MessageCategory category(uint8_t p_midi_fragment);
+
+		// If the byte is a Voice Message status byte return the contained
+		// channel number, otherwise zero.
+		static uint8_t channel(uint8_t p_status_byte);
+
+		// If the byte is a status byte for a message with a fixed number of
+		// additional data bytes, return the number expected, otherwise zero.
+		static size_t expected_data(uint8_t p_status_byte);
+		static size_t expected_data(MIDIMessage p_msg_type);
+
+		// If the fragment is a status byte return the message type
+		// represented, otherwise MIDIMessage::NONE.
+		static MIDIMessage status_to_msg_enum(uint8_t p_status_byte);
+
+	private:
+		int device_index = 0;
+
+		static constexpr size_t DATA_BUFFER_SIZE = 2;
+
+		uint8_t status_byte = 0;
+		uint8_t data_buffer[DATA_BUFFER_SIZE] = { 0 };
+		size_t received_data_len = 0;
+		bool skipping_sys_ex = false;
+	};
+
+	PackedStringArray connected_input_names;
+
 public:
 	static MIDIDriver *get_singleton();
-	void set_singleton();
+
+	MIDIDriver();
+	virtual ~MIDIDriver() = default;
 
 	virtual Error open() = 0;
 	virtual void close() = 0;
 
-	virtual PackedStringArray get_connected_inputs();
-
-	static void receive_input_packet(int device_index, uint64_t timestamp, uint8_t *data, uint32_t length);
-
-	MIDIDriver();
-	virtual ~MIDIDriver() {}
+	PackedStringArray get_connected_inputs() const;
 };
 
 #endif // MIDI_DRIVER_H