#ifndef FIFO__H
#define FIFO__H

#define FIFO( size )\
  struct {\
    unsigned char buf[size];\
    unsigned char tail;\
    unsigned char head;\
  }
#define FIFO_IS_FULL(fifo)   ((fifo.head-fifo.tail)==sizeof(fifo.buf))
#define FIFO_IS_EMPTY(fifo)  (fifo.tail==fifo.head)
#define FIFO_COUNT(fifo)     (fifo.head-fifo.tail)
#define FIFO_SIZE(fifo)      ((sizeof(fifo.buf)))
#define FIFO_SPACE(fifo)     (FIFO_SIZE(fifo)-FIFO_COUNT(fifo))
#define FIFO_PUSH(fifo, byte) \
  {\
    fifo.buf[fifo.head & (sizeof(fifo.buf)-1)]=byte;\
    fifo.head++;\
  }
#define FIFO_FRONT(fifo) (fifo.buf[(fifo).tail & (sizeof(fifo.buf)-1)])
#define FIFO_POP(fifo)   \
{\
      fifo.tail++; \
}
#define FIFO_FLUSH(fifo)   \
  {\
    fifo.tail=0;\
    fifo.head=0;\
  } 
 
#endif