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1 | /* -*-c-*- |
2 | * |
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3 | * $Id: pkbuf.h,v 1.2 2001/01/20 12:06:01 mdw Exp $ |
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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 $ |
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33 | * Revision 1.2 2001/01/20 12:06:01 mdw |
34 | * Define flags with macros, to ensure unsignedness. |
35 | * |
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36 | * Revision 1.1 2000/06/17 10:39:19 mdw |
37 | * Experimental new support for packet buffering. |
38 | * |
39 | */ |
40 | |
41 | #ifndef MLIB_PKBUF_H |
42 | #define MLIB_PKBUF_H |
43 | |
44 | #ifdef __cplusplus |
45 | extern "C" { |
46 | #endif |
47 | |
48 | /*----- Header files ------------------------------------------------------*/ |
49 | |
50 | #include <stddef.h> |
51 | |
52 | #ifndef MLIB_ARENA_H |
53 | # include "arena.h" |
54 | #endif |
55 | |
56 | #ifndef MLIB_BITS_H |
57 | # include "bits.h" |
58 | #endif |
59 | |
60 | /*----- Data structures ---------------------------------------------------*/ |
61 | |
62 | typedef struct pkbuf { |
63 | size_t sz; /* Size of current buffer */ |
64 | size_t len; /* Length of data in the buffer */ |
65 | size_t want; /* Want this many bytes for packet */ |
66 | unsigned f; /* Various state flags */ |
67 | void (*func)(octet */*b*/, size_t /*sz*/, |
68 | struct pkbuf */*pk*/, size_t */*keep*/, |
69 | void */*p*/); /* Handler function */ |
70 | void *p; /* Argument for handler */ |
71 | arena *a; /* Memory allocation arena */ |
72 | octet *buf; /* Actual buffer space */ |
73 | } pkbuf; |
74 | |
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75 | #define PKBUF_ENABLE 1u /* Buffer is currently enabled */ |
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76 | |
77 | /*----- Functions provided ------------------------------------------------*/ |
78 | |
79 | /* --- @pkbuf_flush@ --- * |
80 | * |
81 | * Arguments: @pkbuf *pk@ = pointer to buffer block |
82 | * @octet *p@ = pointer to where to start searching |
83 | * @size_t len@ = length of new material added |
84 | * |
85 | * Returns: --- |
86 | * |
87 | * Use: Flushes any complete packets in a packet buffer. New |
88 | * material is assumed to have been added starting at @p@. If |
89 | * @p@ is null, then the scan starts at the beginning of the |
90 | * buffer, and the size of data already in the buffer is used in |
91 | * place of @len@. |
92 | * |
93 | * It is assumed that the buffer is initially enabled. You |
94 | * shouldn't be contributing data to a disabled buffer anyway. |
95 | * However, the buffer handler may at some point disable itself, |
96 | * and @pkbuf_flush@ can cope with this eventuality. Any |
97 | * pending data is left at the start of the buffer and can be |
98 | * flushed out by calling @pkbuf_flush(b, 0, 0)@ if the buffer |
99 | * is ever re-enabled. |
100 | */ |
101 | |
102 | extern void pkbuf_flush(pkbuf */*pk*/, octet */*p*/, size_t /*len*/); |
103 | |
104 | /* --- @pkbuf_close@ --- * |
105 | * |
106 | * Arguments: @pkbuf *pk@ = pointer to buffer block |
107 | * |
108 | * Returns: --- |
109 | * |
110 | * Use: Informs the client that no more data is likely to arrive. If |
111 | * there is a partial packet in the buffer, it is discarded. |
112 | */ |
113 | |
114 | extern void pkbuf_close(pkbuf */*pk*/); |
115 | |
116 | /* --- @pkbuf_free@ --- * |
117 | * |
118 | * Arguments: @pkbuf *pk@ = pointer to buffer block |
119 | * @octet **p@ = output pointer to free space |
120 | * |
121 | * Returns: Free buffer size. |
122 | * |
123 | * Use: Returns the free portion of a packet buffer. Data can then |
124 | * be written to this portion, and split out into packets by |
125 | * calling @pkbuf_flush@. |
126 | */ |
127 | |
128 | extern size_t pkbuf_free(pkbuf */*pk*/, octet **/*p*/); |
129 | |
130 | /* --- @pkbuf_snarf@ --- * |
131 | * |
132 | * Arguments: @pkbuf *pk@ = pointer to buffer block |
133 | * @const void *p@ = pointer to input data buffer |
134 | * @size_t sz@ = size of data in input buffer |
135 | * |
136 | * Returns: --- |
137 | * |
138 | * Use: Snarfs the data from the input buffer and spits it out as |
139 | * packets. This interface ignores the complexities of dealing |
140 | * with disablement: you should be using @pkbuf_free@ to |
141 | * contribute data if you want to cope with that. |
142 | */ |
143 | |
144 | extern void pkbuf_snarf(pkbuf */*pk*/, const void */*p*/, size_t /*sz*/); |
145 | |
146 | /* --- @pkbuf_want@ --- * |
147 | * |
148 | * Arguments: @pkbuf *pk@ = pointer to buffer block |
149 | * @size_t want@ = how many octets wanted for next packet |
150 | * |
151 | * Returns: --- |
152 | * |
153 | * Use: Sets the desired size for the next packet to be read. If |
154 | * it's larger than the current buffer, the buffer is extended. |
155 | */ |
156 | |
157 | extern void pkbuf_want(pkbuf */*pk*/, size_t /*want*/); |
158 | |
159 | /* --- @pkbuf_init@ --- * |
160 | * |
161 | * Arguments: @pkbuf *pk@ = pointer to buffer block |
162 | * @void (*func)(octet *b, size_t sz, pkbuf *pk,@ |
163 | * @size_t *keep, void *p)@ = |
164 | * handler function |
165 | * @void *p@ = argument pointer for @func@ |
166 | * |
167 | * Returns: --- |
168 | * |
169 | * Use: Initializes a packet buffer block. Any packets are passed to |
170 | * the provided function for handling. |
171 | */ |
172 | |
173 | extern void pkbuf_init(pkbuf */*pk*/, |
174 | void (*/*func*/)(octet */*b*/, size_t /*sz*/, |
175 | pkbuf */*pk*/, size_t */*keep*/, |
176 | void */*p*/), |
177 | void */*p*/); |
178 | |
179 | /* --- @pkbuf_destroy@ --- * |
180 | * |
181 | * Arguments: @pkbuf *pk@ = pointer to buffer block |
182 | * |
183 | * Returns: --- |
184 | * |
185 | * Use: Deallocates a packet buffer and frees any resources it owned. |
186 | */ |
187 | |
188 | extern void pkbuf_destroy(pkbuf */*pk*/); |
189 | |
190 | /*----- That's all, folks -------------------------------------------------*/ |
191 | |
192 | #ifdef __cplusplus |
193 | } |
194 | #endif |
195 | |
196 | #endif |