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/*
* ring.h:
*
* Copyright (c) 2008 James McKenzie <james@fishsoup.dhs.org>,
* All rights reserved.
*
*/
/*
* $Id$
*/
/*
* $Log$
* Revision 1.2 2008/02/12 22:36:46 james
* *** empty log message ***
*
* Revision 1.1 2008/02/08 15:06:42 james
* *** empty log message ***
*
*/
#ifndef __RING_H__
#define __RING_H__
typedef struct
{
uint8_t *ring;
int wptr;
int rptr;
int size;
} Ring;
#define RING_NEXT(r,a) (((a)+1) % ((r)->size))
#define RING_NEXT_R(r) RING_NEXT(r,r->rptr)
#define RING_NEXT_W(r) RING_NEXT(r,r->wptr)
#define RING_EMPTY(r) (((r)->wptr) == ((r)->rptr))
#define RING_FULL(r) (RING_NEXT_W(r) == ((r)->rptr))
static inline int
ring_write_one (Ring * r, uint8_t * c)
{
if (RING_FULL (r))
return 0;
r->ring[r->wptr++] = *c;
if (r->wptr == r->size)
r->wptr = 0;
return 1;
}
static inline int
ring_read_one (Ring * r, uint8_t * c)
{
if (RING_EMPTY (r))
return 0;
*c = r->ring[r->rptr++];
if (r->rptr == r->size)
r->rptr = 0;
return 1;
}
#endif /* __RING_H__ */
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