/*
  HardwareSerial.h - Hardware serial library for Wiring
  Copyright (c) 2006 Nicholas Zambetti.  All right reserved.

  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

  Modified 28 September 2010 by Mark Sproul
*/

#ifndef MarlinSerial_h
#define MarlinSerial_h

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


// Define constants and variables for buffering incoming serial data.  We're
// using a ring buffer (I think), in which rx_buffer_head is the index of the
// location to which to write the next incoming character and rx_buffer_tail
// is the index of the location from which to read.
#define RX_BUFFER_SIZE 128


struct ring_buffer
{
  unsigned char buffer[RX_BUFFER_SIZE];
  int head;
  int tail;
};

#if defined(UBRRH) || defined(UBRR0H)
  extern ring_buffer rx_buffer;
#endif

class MarlinSerial //: public Stream
{
  private:
    volatile uint8_t *_ubrrh;
    volatile uint8_t *_ubrrl;
    volatile uint8_t *_ucsra;
    volatile uint8_t *_ucsrb;
    volatile uint8_t *_udr;
    uint8_t _rxen;
    uint8_t _txen;
    uint8_t _rxcie;
    uint8_t _udre;
    uint8_t _u2x;
  public:
    MarlinSerial(
      volatile uint8_t *ubrrh, volatile uint8_t *ubrrl,
      volatile uint8_t *ucsra, volatile uint8_t *ucsrb,
      volatile uint8_t *udr,
      uint8_t rxen, uint8_t txen, uint8_t rxcie, uint8_t udre, uint8_t u2x);
    void begin(long);
    void end();
    inline int available(void)
    {
      return (unsigned int)(RX_BUFFER_SIZE + rx_buffer.head - rx_buffer.tail) % RX_BUFFER_SIZE;
    }
    int peek(void);
    int read(void);
    void flush(void);
    inline void write(uint8_t c)
    {
      while (!((*_ucsra) & (1 << _udre)))
        ;

      *_udr = c;
    }
    
    
    inline void checkRx(void)
    {
      if((UCSR0A & (1<<RXC0)) != 0) {
        unsigned char c  =  UDR0;
        int i = (unsigned int)(rx_buffer.head + 1) % RX_BUFFER_SIZE;

        // if we should be storing the received character into the location
        // just before the tail (meaning that the head would advance to the
        // current location of the tail), we're about to overflow the buffer
        // and so we don't write the character or advance the head.
        if (i != rx_buffer.tail) {
          rx_buffer.buffer[rx_buffer.head] = c;
          rx_buffer.head = i;
        }
      }
    }
    
    
    private:
    void printNumber(unsigned long, uint8_t);
    void printFloat(double, uint8_t);
    
    
  public:
    void write(const char *str);
    void write( const uint8_t *buffer, size_t size);
    
    void print(const String &);
    void print(const char[]);
    void print(char, int = BYTE);
    void print(unsigned char, int = BYTE);
    void print(int, int = DEC);
    void print(unsigned int, int = DEC);
    void print(long, int = DEC);
    void print(unsigned long, int = DEC);
    void print(double, int = 2);

    void println(const String &s);
    void println(const char[]);
    void println(char, int = BYTE);
    void println(unsigned char, int = BYTE);
    void println(int, int = DEC);
    void println(unsigned int, int = DEC);
    void println(long, int = DEC);
    void println(unsigned long, int = DEC);
    void println(double, int = 2);
    void println(void);
};

#if defined(UBRRH) || defined(UBRR0H)
  extern MarlinSerial MSerial;
#endif

#endif