text: //
  //  Acorn.hpp
  //  Clock Signal
  //
  //  Created by Thomas Harte on 06/11/2016.
  //  Copyright 2016 Thomas Harte. All rights reserved.
  //
  
  #ifndef Storage_Tape_Parsers_Acorn_hpp
  #define Storage_Tape_Parsers_Acorn_hpp
  
  #include "TapeParser.hpp"
  #include "../../../NumberTheory/CRC.hpp"
  #include "../../Disk/DPLL/DigitalPhaseLockedLoop.hpp"
  
  namespace Storage {
  namespace Tape {
  namespace Acorn {
  
  class Shifter: public Storage::DigitalPhaseLockedLoop::Delegate {
  	public:
  		Shifter();
  
  		void process_pulse(const Storage::Tape::Tape::Pulse &pulse);
  
  		class Delegate {
  			public:
  				virtual void acorn_shifter_output_bit(int value) = 0;
  		};
  		void set_delegate(Delegate *delegate) {
  			delegate_ = delegate;
  		}
  
  		void digital_phase_locked_loop_output_bit(int value);
  
  	private:
  		Storage::DigitalPhaseLockedLoop pll_;
  		bool was_high_;
  
  		unsigned int input_pattern_;
  		unsigned int input_bit_counter_;
  
  		Delegate *delegate_;
  };
  
  enum class SymbolType {
  	One, Zero
  };
  
  class Parser: public Storage::Tape::Parser<SymbolType>, public Shifter::Delegate  {
  	public:
  		Parser();
  
  		int get_next_bit(const std::shared_ptr<Storage::Tape::Tape> &tape);
  		int get_next_byte(const std::shared_ptr<Storage::Tape::Tape> &tape);
  		unsigned int get_next_short(const std::shared_ptr<Storage::Tape::Tape> &tape);
  		unsigned int get_next_word(const std::shared_ptr<Storage::Tape::Tape> &tape);
  		void reset_crc();
  		uint16_t get_crc();
  
  		void acorn_shifter_output_bit(int value);
  		void process_pulse(const Storage::Tape::Tape::Pulse &pulse);
  
  	private:
  		bool did_update_shifter(int new_value, int length);
  		CRC::Generator<uint16_t, 0x0000, 0x0000, false, false> crc_;
  		Shifter shifter_;
  };
  
  }
  }
  }
  
  #endif /* Acorn_hpp */
  