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 * $FreeBSD: src/contrib/telnet/telnet/ring.h,v 1.4 2001/11/30 22:28:07 markm 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 */
57typedef 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#ifdef	ENCRYPTION
64    unsigned char	*clearto;	/* Data to this point is clear text */
65    unsigned char	*encryyptedto;	/* Data is encrypted to here */
66#endif	/* ENCRYPTION */
67    int		size;		/* size in bytes of buffer */
68    u_long	consumetime,	/* help us keep straight full, empty, etc. */
69		supplytime;
70} Ring;
71
72/* Here are some functions and macros to deal with the ring buffer */
73
74/* Initialization routine */
75extern int
76	ring_init(Ring *ring, unsigned char *buffer, int count);
77
78/* Data movement routines */
79extern void
80	ring_supply_data(Ring *ring, unsigned char *buffer, int count);
81#ifdef notdef
82extern void
83	ring_consume_data(Ring *ring, unsigned char *buffer, int count);
84#endif
85
86/* Buffer state transition routines */
87extern void
88	ring_supplied(Ring *ring, int count),
89	ring_consumed(Ring *ring, int count);
90
91/* Buffer state query routines */
92extern int
93	ring_at_mark(Ring *),
94	ring_empty_count(Ring *ring),
95	ring_empty_consecutive(Ring *ring),
96	ring_full_count(Ring *ring),
97	ring_full_consecutive(Ring *ring);
98
99#ifdef	ENCRYPTION
100extern void
101	ring_encrypt(Ring *ring, void (*func)(unsigned char *, int)),
102	ring_clearto(Ring *ring);
103#endif	/* ENCRYPTION */
104
105extern void
106	ring_clear_mark(Ring *),
107	ring_mark(Ring *);
108