Tidied a little, started working towards supporting speaker output.

SignalProcessing/Stepper.hpp

@@ -0,0 +1,46 @@
+//
+//  Stepper.hpp
+//  Clock Signal
+//
+//  Created by Thomas Harte on 12/01/2016.
+//  Copyright © 2016 Thomas Harte. All rights reserved.
+//
+
+#ifndef Stepper_hpp
+#define Stepper_hpp
+
+#include <stdint.h>
+
+namespace SignalProcessing {
+
+class Stepper
+{
+	public:
+		Stepper(uint64_t input_rate, uint64_t output_rate)
+		{
+			whole_step_ = output_rate / input_rate;
+			adjustment_up_ = (int64_t)(output_rate % input_rate) << 1;
+			adjustment_down_ = (int64_t)input_rate << 1;
+		}
+
+		inline uint64_t update()
+		{
+			uint64_t update = whole_step_;
+			accumulated_error_ += adjustment_up_;
+			if(accumulated_error_ > 0)
+			{
+				update++;
+				accumulated_error_ -= adjustment_down_;
+			}
+			return update;
+		}
+
+	private:
+		uint64_t whole_step_;
+		int64_t adjustment_up_, adjustment_down_;
+		int64_t accumulated_error_;
+};
+
+}
+
+#endif /* Stepper_hpp */