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ring.h revision 1.3 
      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  *	$Id: ring.h,v 1.3 1994/02/25 03:00:36 cgd Exp $
     35  */
     36 
     37 #if defined(P)
     38 # undef P
     39 #endif
     40 
     41 #if defined(__STDC__) || defined(LINT_ARGS)
     42 # define	P(x)	x
     43 #else
     44 # define	P(x)	()
     45 #endif
     46 
     47 /*
     48  * This defines a structure for a ring buffer.
     49  *
     50  * The circular buffer has two parts:
     51  *(((
     52  *	full:	[consume, supply)
     53  *	empty:	[supply, consume)
     54  *]]]
     55  *
     56  */
     57 typedef struct {
     58     unsigned char	*consume,	/* where data comes out of */
     59 			*supply,	/* where data comes in to */
     60 			*bottom,	/* lowest address in buffer */
     61 			*top,		/* highest address+1 in buffer */
     62 			*mark;		/* marker (user defined) */
     63     int		size;		/* size in bytes of buffer */
     64     u_long	consumetime,	/* help us keep straight full, empty, etc. */
     65 		supplytime;
     66 } Ring;
     67 
     68 /* Here are some functions and macros to deal with the ring buffer */
     69 
     70 /* Initialization routine */
     71 extern int
     72 	ring_init P((Ring *ring, unsigned char *buffer, int count));
     73 
     74 /* Data movement routines */
     75 extern void
     76 	ring_supply_data P((Ring *ring, unsigned char *buffer, int count));
     77 #ifdef notdef
     78 extern void
     79 	ring_consume_data P((Ring *ring, unsigned char *buffer, int count));
     80 #endif
     81 
     82 /* Buffer state transition routines */
     83 extern void
     84 	ring_supplied P((Ring *ring, int count)),
     85 	ring_consumed P((Ring *ring, int count));
     86 
     87 /* Buffer state query routines */
     88 extern int
     89 	ring_empty_count P((Ring *ring)),
     90 	ring_empty_consecutive P((Ring *ring)),
     91 	ring_full_count P((Ring *ring)),
     92 	ring_full_consecutive P((Ring *ring));
     93 
     94 
     95 extern void
     96     ring_clear_mark(),
     97     ring_mark();
     98