/*
SoftwareSerial.h 
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.

This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

The latest version of this library can always be found at
http://arduiniana.org.
*/

#ifndef SoftwareSerial_h
#define SoftwareSerial_h

#include <inttypes.h>
#include <Stream.h>

/******************************************************************************
* Definitions
******************************************************************************/

#ifndef _SS_MAX_RX_BUFF
#define _SS_MAX_RX_BUFF 64 // RX buffer size
#endif

#ifndef GCC_VERSION
#define GCC_VERSION (__GNUC__ * 10000 + __GNUC_MINOR__ * 100 + __GNUC_PATCHLEVEL__)
#endif

class SoftwareSerial : public Stream
{
private:
  // per object data
  uint8_t _receivePin;
  uint16_t _receiveBitMask;
  uint32_t _receivePortRegister;
  uint8_t _transmitPin;
  uint16_t _transmitBitMask;
  uint32_t _transmitPortRegister;
  uint8_t _int_maskLine;

  // must never be 0!
  uint32_t _rx_delay_centering;
  uint32_t _rx_delay_intrabit;
  uint32_t _rx_delay_stopbit;
  uint32_t _tx_delay;

  uint16_t _buffer_overflow:1;
  uint16_t _inverse_logic:1;

  // static data
  static uint8_t _receive_buffer[_SS_MAX_RX_BUFF]; 
  static volatile uint8_t _receive_buffer_tail;
  static volatile uint8_t _receive_buffer_head;
  static SoftwareSerial *active_object;

  // private methods
  void recv() __attribute__((noinline, section(".ram_text")));
  uint8_t rx_pin_read();
  void setTX(uint8_t transmitPin);
  void setRX(uint8_t receivePin);
  inline void setRxIntMsk(bool enable) __attribute__((__always_inline__));

  // Return num - sub, or 1 if the result would be < 1
  static uint32_t subtract_cap(uint32_t num, uint16_t sub);

  // private static method for timing
  static void tunedDelay(uint32_t delayTicks) __attribute__((noinline, section(".ram_text")));

public:
  // public methods
  SoftwareSerial(uint8_t receivePin, uint8_t transmitPin, bool inverse_logic = false);
  ~SoftwareSerial();
  void begin(long speed);
  bool listen();
  void end();
  bool isListening() { return this == active_object; }
  bool stopListening();
  bool overflow() 
  { 
    bool ret = _buffer_overflow; 
    if (ret) 
      _buffer_overflow = false; 
    return ret; 
  }
  int peek();

  virtual size_t write(uint8_t byte) __attribute__((noinline, section(".ram_text")));
  virtual int read();
  virtual int available();
  virtual void flush();
  operator bool() { return true; }
  
  using Print::write;

  // public only for easy access by interrupt handlers
  static void handle_interrupt() __attribute__((noinline, section(".ram_text")));
};

#endif