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ring.h revision 1.6 
      1 /*	$NetBSD: ring.h,v 1.6 1998/02/27 10:44:14 christos Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 1988, 1993
      5  *	The Regents of the University of California.  All rights reserved.
      6  *
      7  * Redistribution and use in source and binary forms, with or without
      8  * modification, are permitted provided that the following conditions
      9  * are met:
     10  * 1. Redistributions of source code must retain the above copyright
     11  *    notice, this list of conditions and the following disclaimer.
     12  * 2. Redistributions in binary form must reproduce the above copyright
     13  *    notice, this list of conditions and the following disclaimer in the
     14  *    documentation and/or other materials provided with the distribution.
     15  * 3. All advertising materials mentioning features or use of this software
     16  *    must display the following acknowledgement:
     17  *	This product includes software developed by the University of
     18  *	California, Berkeley and its contributors.
     19  * 4. Neither the name of the University nor the names of its contributors
     20  *    may be used to endorse or promote products derived from this software
     21  *    without specific prior written permission.
     22  *
     23  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     33  * SUCH DAMAGE.
     34  *
     35  *	from: @(#)ring.h	8.1 (Berkeley) 6/6/93
     36  */
     37 
     38 #include <sys/cdefs.h>
     39 #define P __P
     40 
     41 /*
     42  * This defines a structure for a ring buffer.
     43  *
     44  * The circular buffer has two parts:
     45  *(((
     46  *	full:	[consume, supply)
     47  *	empty:	[supply, consume)
     48  *]]]
     49  *
     50  */
     51 typedef struct {
     52     unsigned char	*consume,	/* where data comes out of */
     53 			*supply,	/* where data comes in to */
     54 			*bottom,	/* lowest address in buffer */
     55 			*top,		/* highest address+1 in buffer */
     56 			*mark;		/* marker (user defined) */
     57     int		size;		/* size in bytes of buffer */
     58     u_long	consumetime,	/* help us keep straight full, empty, etc. */
     59 		supplytime;
     60 } Ring;
     61 
     62 /* Here are some functions and macros to deal with the ring buffer */
     63 
     64 /* Initialization routine */
     65 extern int
     66 	ring_init P((Ring *ring, unsigned char *buffer, int count));
     67 
     68 /* Data movement routines */
     69 extern void
     70 	ring_supply_data P((Ring *ring, unsigned char *buffer, int count));
     71 #ifdef notdef
     72 extern void
     73 	ring_consume_data P((Ring *ring, unsigned char *buffer, int count));
     74 #endif
     75 
     76 /* Buffer state transition routines */
     77 extern void
     78 	ring_supplied P((Ring *ring, int count)),
     79 	ring_consumed P((Ring *ring, int count));
     80 
     81 /* Buffer state query routines */
     82 extern int
     83 	ring_empty_count P((Ring *ring)),
     84 	ring_empty_consecutive P((Ring *ring)),
     85 	ring_full_count P((Ring *ring)),
     86 	ring_full_consecutive P((Ring *ring)),
     87 	ring_at_mark P((Ring *ring));
     88 
     89 
     90 extern void
     91 	ring_clear_mark P((Ring *ring)),
     92 	ring_mark P((Ring *ring));
     93