/*
 * Copyright (c) 1988 Regents of the University of California.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms are permitted
 * provided that this notice is preserved and that due credit is given
 * to the University of California at Berkeley. The name of the University
 * may not be used to endorse or promote products derived from this
 * software without specific prior written permission. This software
 * is provided ``as is'' without express or implied warranty.
 *
 *	@(#)ring.h	1.6 (Berkeley) 3/8/88
 */

/*
 * This defines a structure for a ring buffer.
 *
 * The circular buffer has two parts:
 *(((
 *	full:	[consume, supply)
 *	empty:	[supply, consume)
 *]]]
 *
 */
typedef struct {
    char	*consume,	/* where data comes out of */
    		*supply,	/* where data comes in to */
		*bottom,	/* lowest address in buffer */
		*top,		/* highest address+1 in buffer */
		*mark;		/* marker (user defined) */
    int		size;		/* size in bytes of buffer */
    u_long	consumetime,	/* help us keep straight full, empty, etc. */
		supplytime;
} Ring;

/* Here are some functions and macros to deal with the ring buffer */


#if	defined(LINT_ARGS)

/* Initialization routine */
extern int
	ring_init(Ring *ring, char *buffer, int count);

/* Data movement routines */
extern void
	ring_supply_data(Ring *ring, char *buffer, int count),
	ring_consume_data(Ring *ring, char *buffer, int count);

/* Buffer state transition routines */
extern void
	ring_supplied(Ring *ring, int count),
	ring_consumed(Ring *ring, int count);

/* Buffer state query routines */
extern int
	ring_empty_count(Ring *ring),
	ring_empty_consecutive(Ring *ring),
	ring_full_count(Ring *ring),
	ring_full_consecutive(Ring *ring);

#endif	/* defined(LINT_ARGS) */