xref: /freebsd/contrib/telnet/telnet/ring.h (revision e4e9813eb92cd7c4d4b819a8fbed5cbd3d92f5d8)
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  * $FreeBSD$
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 #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 */
75 extern int
76 	ring_init(Ring *ring, unsigned char *buffer, int count);
77 
78 /* Data movement routines */
79 extern void
80 	ring_supply_data(Ring *ring, unsigned char *buffer, int count);
81 #ifdef notdef
82 extern void
83 	ring_consume_data(Ring *ring, unsigned char *buffer, int count);
84 #endif
85 
86 /* Buffer state transition routines */
87 extern void
88 	ring_supplied(Ring *ring, int count),
89 	ring_consumed(Ring *ring, int count);
90 
91 /* Buffer state query routines */
92 extern 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
100 extern void
101 	ring_encrypt(Ring *ring, void (*func)(unsigned char *, int)),
102 	ring_clearto(Ring *ring);
103 #endif	/* ENCRYPTION */
104 
105 extern void
106 	ring_clear_mark(Ring *),
107 	ring_mark(Ring *);
108