#ifndef BUFFER_H
#define BUFFER_H

#include <stdlib.h>
#include <math.h>
#include <oulib.h>

/**
   Buffer structure.  Implementation of a circular byte buffer.

*/
typedef struct  {
  /** Pointer to the storage space. */
  char *buffer;
   /** Total number of bytes available for storage.  */
  uint16_t size;
  /** Current index of the next byte to be removed. */
  volatile int16_t front;
  /** Current index of the next location to receive a byte.  */
  volatile int16_t back;   
} BUFFER;  


extern BUFFER* buffer_create(uint16_t size);
extern void buffer_add(BUFFER* buf, char c);
extern char buffer_remove(BUFFER* buf);
extern int8_t buffer_state(BUFFER* buf);
extern void buffer_reset(BUFFER* buf, uint16_t front, uint16_t back);
extern uint16_t buffer_nbytes(BUFFER* buf);
extern void buffer_flush(BUFFER* buf);

/**
   Indicate whether the buffer is full

   <P>
   @param buf A pointer to an existing and initialized BUFFER structure.
   @return 1 if the buffer is full (with size-1 bytes), or <BR>
   0 if the buffer is not full

   @author Andrew H. Fagg (fagg@cs.ou.edu)

   \ingroup buffer
 */

#define BUFFER_FULL(buf) (buffer_nbytes(buf) == ((buf)->size - 1))

/**
   Indicate whether the buffer is empty

   <P>
   @param buf A pointer to an existing and initialized BUFFER structure.
   @return 1 if the buffer is empty (with 0 bytes), or <BR>
   0 if the buffer is not empty

   @author Andrew H. Fagg (fagg@cs.ou.edu)

   \ingroup buffer
 */

#define BUFFER_EMPTY(buf) ((buf)->front == (buf)->back)


#endif