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ring.h revision 1.4 
      1 /*
      2  * Copyright (c) 1988, 1993
      3  *	The Regents of the University of California.  All rights reserved.
      4  *
      5  * Redistribution and use in source and binary forms, with or without
      6  * modification, are permitted provided that the following conditions
      7  * are met:
      8  * 1. Redistributions of source code must retain the above copyright
      9  *    notice, this list of conditions and the following disclaimer.
     10  * 2. Redistributions in binary form must reproduce the above copyright
     11  *    notice, this list of conditions and the following disclaimer in the
     12  *    documentation and/or other materials provided with the distribution.
     13  * 3. All advertising materials mentioning features or use of this software
     14  *    must display the following acknowledgement:
     15  *	This product includes software developed by the University of
     16  *	California, Berkeley and its contributors.
     17  * 4. Neither the name of the University nor the names of its contributors
     18  *    may be used to endorse or promote products derived from this software
     19  *    without specific prior written permission.
     20  *
     21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     31  * SUCH DAMAGE.
     32  *
     33  *	from: @(#)ring.h	8.1 (Berkeley) 6/6/93
     34  *	$NetBSD: ring.h,v 1.4 1996/02/24 01:18:45 jtk Exp $
     35  */
     36 
     37 #include <sys/cdefs.h>
     38 #define P __P
     39 
     40 /*
     41  * This defines a structure for a ring buffer.
     42  *
     43  * The circular buffer has two parts:
     44  *(((
     45  *	full:	[consume, supply)
     46  *	empty:	[supply, consume)
     47  *]]]
     48  *
     49  */
     50 typedef struct {
     51     unsigned char	*consume,	/* where data comes out of */
     52 			*supply,	/* where data comes in to */
     53 			*bottom,	/* lowest address in buffer */
     54 			*top,		/* highest address+1 in buffer */
     55 			*mark;		/* marker (user defined) */
     56     int		size;		/* size in bytes of buffer */
     57     u_long	consumetime,	/* help us keep straight full, empty, etc. */
     58 		supplytime;
     59 } Ring;
     60 
     61 /* Here are some functions and macros to deal with the ring buffer */
     62 
     63 /* Initialization routine */
     64 extern int
     65 	ring_init P((Ring *ring, unsigned char *buffer, int count));
     66 
     67 /* Data movement routines */
     68 extern void
     69 	ring_supply_data P((Ring *ring, unsigned char *buffer, int count));
     70 #ifdef notdef
     71 extern void
     72 	ring_consume_data P((Ring *ring, unsigned char *buffer, int count));
     73 #endif
     74 
     75 /* Buffer state transition routines */
     76 extern void
     77 	ring_supplied P((Ring *ring, int count)),
     78 	ring_consumed P((Ring *ring, int count));
     79 
     80 /* Buffer state query routines */
     81 extern int
     82 	ring_empty_count P((Ring *ring)),
     83 	ring_empty_consecutive P((Ring *ring)),
     84 	ring_full_count P((Ring *ring)),
     85 	ring_full_consecutive P((Ring *ring));
     86 
     87 
     88 extern void
     89     ring_clear_mark(),
     90     ring_mark();
     91