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 *	@(#)ring.h	8.1 (Berkeley) 6/6/93
34 */
35
36/* $Id$ */
37
38/*
39 * This defines a structure for a ring buffer.
40 *
41 * The circular buffer has two parts:
42 *(((
43 *	full:	[consume, supply)
44 *	empty:	[supply, consume)
45 *]]]
46 *
47 */
48typedef struct {
49    unsigned char	*consume,	/* where data comes out of */
50			*supply,	/* where data comes in to */
51			*bottom,	/* lowest address in buffer */
52			*top,		/* highest address+1 in buffer */
53			*mark;		/* marker (user defined) */
54#if	defined(ENCRYPTION)
55    unsigned char	*clearto;	/* Data to this point is clear text */
56    unsigned char	*encryyptedto;	/* Data is encrypted to here */
57#endif
58    int		size;		/* size in bytes of buffer */
59    u_long	consumetime,	/* help us keep straight full, empty, etc. */
60		supplytime;
61} Ring;
62
63/* Here are some functions and macros to deal with the ring buffer */
64
65/* Initialization routine */
66extern int
67	ring_init (Ring *ring, unsigned char *buffer, int count);
68
69/* Data movement routines */
70extern void
71	ring_supply_data (Ring *ring, unsigned char *buffer, int count);
72#ifdef notdef
73extern void
74	ring_consume_data (Ring *ring, unsigned char *buffer, int count);
75#endif
76
77/* Buffer state transition routines */
78extern void
79	ring_supplied (Ring *ring, int count),
80	ring_consumed (Ring *ring, int count);
81
82/* Buffer state query routines */
83extern int
84	ring_empty_count (Ring *ring),
85	ring_empty_consecutive (Ring *ring),
86	ring_full_count (Ring *ring),
87	ring_full_consecutive (Ring *ring);
88
89#if	defined(ENCRYPTION)
90extern void
91	ring_encrypt (Ring *ring, void (*func)(unsigned char *, int)),
92	ring_clearto (Ring *ring);
93#endif
94
95extern int ring_at_mark(Ring *ring);
96
97extern void
98    ring_clear_mark(Ring *ring),
99    ring_mark(Ring *ring);
100