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. Neither the name of the University nor the names of its contributors
14 *    may be used to endorse or promote products derived from this software
15 *    without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 *
29 *	@(#)ring.h	8.1 (Berkeley) 6/6/93
30 * $FreeBSD: stable/11/contrib/telnet/telnet/ring.h 351432 2019-08-23 17:40:47Z emaste $
31 */
32
33#if defined(P)
34# undef P
35#endif
36
37#if defined(__STDC__) || defined(LINT_ARGS)
38# define	P(x)	x
39#else
40# define	P(x)	()
41#endif
42
43/*
44 * This defines a structure for a ring buffer.
45 *
46 * The circular buffer has two parts:
47 *(((
48 *	full:	[consume, supply)
49 *	empty:	[supply, consume)
50 *]]]
51 *
52 */
53typedef struct {
54    unsigned char	*consume,	/* where data comes out of */
55			*supply,	/* where data comes in to */
56			*bottom,	/* lowest address in buffer */
57			*top,		/* highest address+1 in buffer */
58			*mark;		/* marker (user defined) */
59#ifdef	ENCRYPTION
60    unsigned char	*clearto;	/* Data to this point is clear text */
61    unsigned char	*encryyptedto;	/* Data is encrypted to here */
62#endif	/* ENCRYPTION */
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 */
71extern int
72	ring_init(Ring *ring, unsigned char *buffer, int count);
73
74/* Data movement routines */
75extern void
76	ring_supply_data(Ring *ring, unsigned char *buffer, int count);
77#ifdef notdef
78extern void
79	ring_consume_data(Ring *ring, unsigned char *buffer, int count);
80#endif
81
82/* Buffer state transition routines */
83extern void
84	ring_supplied(Ring *ring, int count),
85	ring_consumed(Ring *ring, int count);
86
87/* Buffer state query routines */
88extern int
89	ring_at_mark(Ring *),
90	ring_empty_count(Ring *ring),
91	ring_empty_consecutive(Ring *ring),
92	ring_full_count(Ring *ring),
93	ring_full_consecutive(Ring *ring);
94
95#ifdef	ENCRYPTION
96extern void
97	ring_encrypt(Ring *ring, void (*func)(unsigned char *, int)),
98	ring_clearto(Ring *ring);
99#endif	/* ENCRYPTION */
100
101extern void
102	ring_clear_mark(Ring *),
103	ring_mark(Ring *);
104