#ifndef __FIFO_H__
#define __FIFO_H__

#define CONCAT3(str1, str2, str3) str1 ## str2 ## str3
#define CONCAT4(str1, str2, str3, str4) str1 ## str2 ## str3 ## str4

#define FIFO_TYPE char
#define FIFO_T(type) CONCAT3(fifo_, type, _t)
#define FIFO_METHOD(type, name) CONCAT4(fifo_, type, _, name)

#ifndef FIFO_SIZE_T
#define FIFO_SIZE_T unsigned char
#endif

typedef struct {
	FIFO_TYPE *buffer;
	FIFO_SIZE_T size;
	FIFO_TYPE *prius;
	FIFO_TYPE *follower;
} FIFO_T(FIFO_TYPE);

/* The mechanizm of the ring buffer.
 * 1) The "follower" can reach the "prius" , but not overtake it. 
 * 2) The "prius" can not reach the "follower" more than overtake it.
 */

FIFO_SIZE_T FIFO_METHOD(FIFO_TYPE, write) (FIFO_T(FIFO_TYPE) *fifo, FIFO_TYPE *values, FIFO_SIZE_T size);
FIFO_SIZE_T FIFO_METHOD(FIFO_TYPE, put) (FIFO_T(FIFO_TYPE) *fifo, FIFO_TYPE *value);
FIFO_SIZE_T FIFO_METHOD(FIFO_TYPE, read) (FIFO_T(FIFO_TYPE) *fifo, FIFO_TYPE *buffer, FIFO_SIZE_T size);
FIFO_SIZE_T FIFO_METHOD(FIFO_TYPE, get) (FIFO_T(FIFO_TYPE) *fifo, FIFO_TYPE *buffer);
FIFO_SIZE_T FIFO_METHOD(FIFO_TYPE, size) (FIFO_T(FIFO_TYPE) *fifo);
FIFO_SIZE_T FIFO_METHOD(FIFO_TYPE, margin) (FIFO_T(FIFO_TYPE) *fifo);
FIFO_T(FIFO_TYPE) * FIFO_METHOD(FIFO_TYPE,init) (FIFO_T(FIFO_TYPE) *fifo, FIFO_TYPE *buffer, FIFO_SIZE_T size);

#ifndef NULL
#define NULL 0
#endif

#endif /* __FIFO_H__ */