chiark / gitweb /
Experimental new support for packet buffering.
[mLib] / pkbuf.h
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436fddaa 1/* -*-c-*-
2 *
3 * $Id: pkbuf.h,v 1.1 2000/06/17 10:39:19 mdw Exp $
4 *
5 * Simple packet buffering
6 *
7 * (c) 2000 Straylight/Edgeware
8 */
9
10/*----- Licensing notice --------------------------------------------------*
11 *
12 * This file is part of the mLib utilities library.
13 *
14 * mLib is free software; you can redistribute it and/or modify
15 * it under the terms of the GNU Library General Public License as
16 * published by the Free Software Foundation; either version 2 of the
17 * License, or (at your option) any later version.
18 *
19 * mLib is distributed in the hope that it will be useful,
20 * but WITHOUT ANY WARRANTY; without even the implied warranty of
21 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
22 * GNU Library General Public License for more details.
23 *
24 * You should have received a copy of the GNU Library General Public
25 * License along with mLib; if not, write to the Free
26 * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
27 * MA 02111-1307, USA.
28 */
29
30/*----- Revision history --------------------------------------------------*
31 *
32 * $Log: pkbuf.h,v $
33 * Revision 1.1 2000/06/17 10:39:19 mdw
34 * Experimental new support for packet buffering.
35 *
36 */
37
38#ifndef MLIB_PKBUF_H
39#define MLIB_PKBUF_H
40
41#ifdef __cplusplus
42 extern "C" {
43#endif
44
45/*----- Header files ------------------------------------------------------*/
46
47#include <stddef.h>
48
49#ifndef MLIB_ARENA_H
50# include "arena.h"
51#endif
52
53#ifndef MLIB_BITS_H
54# include "bits.h"
55#endif
56
57/*----- Data structures ---------------------------------------------------*/
58
59typedef struct pkbuf {
60 size_t sz; /* Size of current buffer */
61 size_t len; /* Length of data in the buffer */
62 size_t want; /* Want this many bytes for packet */
63 unsigned f; /* Various state flags */
64 void (*func)(octet */*b*/, size_t /*sz*/,
65 struct pkbuf */*pk*/, size_t */*keep*/,
66 void */*p*/); /* Handler function */
67 void *p; /* Argument for handler */
68 arena *a; /* Memory allocation arena */
69 octet *buf; /* Actual buffer space */
70} pkbuf;
71
72enum {
73 PKBUF_ENABLE = 1 /* Buffer is currently enabled */
74};
75
76/*----- Functions provided ------------------------------------------------*/
77
78/* --- @pkbuf_flush@ --- *
79 *
80 * Arguments: @pkbuf *pk@ = pointer to buffer block
81 * @octet *p@ = pointer to where to start searching
82 * @size_t len@ = length of new material added
83 *
84 * Returns: ---
85 *
86 * Use: Flushes any complete packets in a packet buffer. New
87 * material is assumed to have been added starting at @p@. If
88 * @p@ is null, then the scan starts at the beginning of the
89 * buffer, and the size of data already in the buffer is used in
90 * place of @len@.
91 *
92 * It is assumed that the buffer is initially enabled. You
93 * shouldn't be contributing data to a disabled buffer anyway.
94 * However, the buffer handler may at some point disable itself,
95 * and @pkbuf_flush@ can cope with this eventuality. Any
96 * pending data is left at the start of the buffer and can be
97 * flushed out by calling @pkbuf_flush(b, 0, 0)@ if the buffer
98 * is ever re-enabled.
99 */
100
101extern void pkbuf_flush(pkbuf */*pk*/, octet */*p*/, size_t /*len*/);
102
103/* --- @pkbuf_close@ --- *
104 *
105 * Arguments: @pkbuf *pk@ = pointer to buffer block
106 *
107 * Returns: ---
108 *
109 * Use: Informs the client that no more data is likely to arrive. If
110 * there is a partial packet in the buffer, it is discarded.
111 */
112
113extern void pkbuf_close(pkbuf */*pk*/);
114
115/* --- @pkbuf_free@ --- *
116 *
117 * Arguments: @pkbuf *pk@ = pointer to buffer block
118 * @octet **p@ = output pointer to free space
119 *
120 * Returns: Free buffer size.
121 *
122 * Use: Returns the free portion of a packet buffer. Data can then
123 * be written to this portion, and split out into packets by
124 * calling @pkbuf_flush@.
125 */
126
127extern size_t pkbuf_free(pkbuf */*pk*/, octet **/*p*/);
128
129/* --- @pkbuf_snarf@ --- *
130 *
131 * Arguments: @pkbuf *pk@ = pointer to buffer block
132 * @const void *p@ = pointer to input data buffer
133 * @size_t sz@ = size of data in input buffer
134 *
135 * Returns: ---
136 *
137 * Use: Snarfs the data from the input buffer and spits it out as
138 * packets. This interface ignores the complexities of dealing
139 * with disablement: you should be using @pkbuf_free@ to
140 * contribute data if you want to cope with that.
141 */
142
143extern void pkbuf_snarf(pkbuf */*pk*/, const void */*p*/, size_t /*sz*/);
144
145/* --- @pkbuf_want@ --- *
146 *
147 * Arguments: @pkbuf *pk@ = pointer to buffer block
148 * @size_t want@ = how many octets wanted for next packet
149 *
150 * Returns: ---
151 *
152 * Use: Sets the desired size for the next packet to be read. If
153 * it's larger than the current buffer, the buffer is extended.
154 */
155
156extern void pkbuf_want(pkbuf */*pk*/, size_t /*want*/);
157
158/* --- @pkbuf_init@ --- *
159 *
160 * Arguments: @pkbuf *pk@ = pointer to buffer block
161 * @void (*func)(octet *b, size_t sz, pkbuf *pk,@
162 * @size_t *keep, void *p)@ =
163 * handler function
164 * @void *p@ = argument pointer for @func@
165 *
166 * Returns: ---
167 *
168 * Use: Initializes a packet buffer block. Any packets are passed to
169 * the provided function for handling.
170 */
171
172extern void pkbuf_init(pkbuf */*pk*/,
173 void (*/*func*/)(octet */*b*/, size_t /*sz*/,
174 pkbuf */*pk*/, size_t */*keep*/,
175 void */*p*/),
176 void */*p*/);
177
178/* --- @pkbuf_destroy@ --- *
179 *
180 * Arguments: @pkbuf *pk@ = pointer to buffer block
181 *
182 * Returns: ---
183 *
184 * Use: Deallocates a packet buffer and frees any resources it owned.
185 */
186
187extern void pkbuf_destroy(pkbuf */*pk*/);
188
189/*----- That's all, folks -------------------------------------------------*/
190
191#ifdef __cplusplus
192 }
193#endif
194
195#endif