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      1 /*	$NetBSD: ring.h,v 1.11 2018/12/13 09:07:53 maya 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. Neither the name of the University nor the names of its contributors
     16  *    may be used to endorse or promote products derived from this software
     17  *    without specific prior written permission.
     18  *
     19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     29  * SUCH DAMAGE.
     30  *
     31  *	from: @(#)ring.h	8.1 (Berkeley) 6/6/93
     32  */
     33 
     34 #include <sys/cdefs.h>
     35 
     36 /*
     37  * This defines a structure for a ring buffer.
     38  *
     39  * The circular buffer has two parts:
     40  *(((
     41  *	full:	[consume, supply)
     42  *	empty:	[supply, consume)
     43  *]]]
     44  *
     45  */
     46 typedef struct {
     47     unsigned char	*consume,	/* where data comes out of */
     48 			*supply,	/* where data comes in to */
     49 			*bottom,	/* lowest address in buffer */
     50 			*top,		/* highest address+1 in buffer */
     51 			*mark;		/* marker (user defined) */
     52 #ifdef	ENCRYPTION
     53     unsigned char	*clearto;	/* Data to this point is clear text */
     54     unsigned char	*encryyptedto;	/* Data is encrypted to here */
     55 #endif	/* ENCRYPTION */
     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 /* Ring buffer structures which are shared */
     62 
     63 extern Ring
     64     netoring,
     65     netiring,
     66     ttyoring,
     67     ttyiring;
     68 
     69 /* Here are some functions and macros to deal with the ring buffer */
     70 
     71 /* Initialization routine */
     72 extern int
     73 	ring_init(Ring *ring, unsigned char *buffer, int count);
     74 
     75 /* Data movement routines */
     76 extern void
     77 	ring_supply_data(Ring *ring, unsigned char *buffer, int count);
     78 
     79 /* Buffer state transition routines */
     80 extern void
     81 	ring_supplied(Ring *ring, int count),
     82 	ring_consumed(Ring *ring, int count);
     83 
     84 /* Buffer state query routines */
     85 extern int
     86 	ring_empty_count(Ring *ring),
     87 	ring_empty_consecutive(Ring *ring),
     88 	ring_full_count(Ring *ring),
     89 	ring_full_consecutive(Ring *ring),
     90 	ring_at_mark(Ring *ring);
     91 
     92 #ifdef	ENCRYPTION
     93 extern void
     94 	ring_encrypt(Ring *ring, void (*func)(unsigned char *, int)),
     95 	ring_clearto(Ring *ring);
     96 #endif	/* ENCRYPTION */
     97 
     98 extern void
     99 	ring_clear_mark(Ring *ring),
    100 	ring_mark(Ring *ring);
    101