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1 | /* -*-c-*- |
2 | * |
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3 | * $Id: pkbuf.h,v 1.5 2004/04/08 01:36:13 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 | |
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30 | #ifndef MLIB_PKBUF_H |
31 | #define MLIB_PKBUF_H |
32 | |
33 | #ifdef __cplusplus |
34 | extern "C" { |
35 | #endif |
36 | |
37 | /*----- Header files ------------------------------------------------------*/ |
38 | |
39 | #include <stddef.h> |
40 | |
41 | #ifndef MLIB_ARENA_H |
42 | # include "arena.h" |
43 | #endif |
44 | |
45 | #ifndef MLIB_BITS_H |
46 | # include "bits.h" |
47 | #endif |
48 | |
49 | /*----- Data structures ---------------------------------------------------*/ |
50 | |
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51 | struct pkbuf; |
52 | |
53 | typedef void pkbuf_func(octet */*b*/, size_t /*sz*/, |
54 | struct pkbuf */*pk*/, size_t */*keep*/, |
55 | void */*p*/); |
56 | |
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57 | typedef struct pkbuf { |
58 | size_t sz; /* Size of current buffer */ |
59 | size_t len; /* Length of data in the buffer */ |
60 | size_t want; /* Want this many bytes for packet */ |
61 | unsigned f; /* Various state flags */ |
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62 | pkbuf_func *func; /* Handler function */ |
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63 | void *p; /* Argument for handler */ |
64 | arena *a; /* Memory allocation arena */ |
65 | octet *buf; /* Actual buffer space */ |
66 | } pkbuf; |
67 | |
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68 | #define PKBUF_ENABLE 1u /* Buffer is currently enabled */ |
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69 | #define PKBUF_CLOSE 2u /* Buffer is now closed */ |
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70 | |
71 | /*----- Functions provided ------------------------------------------------*/ |
72 | |
73 | /* --- @pkbuf_flush@ --- * |
74 | * |
75 | * Arguments: @pkbuf *pk@ = pointer to buffer block |
76 | * @octet *p@ = pointer to where to start searching |
77 | * @size_t len@ = length of new material added |
78 | * |
79 | * Returns: --- |
80 | * |
81 | * Use: Flushes any complete packets in a packet buffer. New |
82 | * material is assumed to have been added starting at @p@. If |
83 | * @p@ is null, then the scan starts at the beginning of the |
84 | * buffer, and the size of data already in the buffer is used in |
85 | * place of @len@. |
86 | * |
87 | * It is assumed that the buffer is initially enabled. You |
88 | * shouldn't be contributing data to a disabled buffer anyway. |
89 | * However, the buffer handler may at some point disable itself, |
90 | * and @pkbuf_flush@ can cope with this eventuality. Any |
91 | * pending data is left at the start of the buffer and can be |
92 | * flushed out by calling @pkbuf_flush(b, 0, 0)@ if the buffer |
93 | * is ever re-enabled. |
94 | */ |
95 | |
96 | extern void pkbuf_flush(pkbuf */*pk*/, octet */*p*/, size_t /*len*/); |
97 | |
98 | /* --- @pkbuf_close@ --- * |
99 | * |
100 | * Arguments: @pkbuf *pk@ = pointer to buffer block |
101 | * |
102 | * Returns: --- |
103 | * |
104 | * Use: Informs the client that no more data is likely to arrive. If |
105 | * there is a partial packet in the buffer, it is discarded. |
106 | */ |
107 | |
108 | extern void pkbuf_close(pkbuf */*pk*/); |
109 | |
110 | /* --- @pkbuf_free@ --- * |
111 | * |
112 | * Arguments: @pkbuf *pk@ = pointer to buffer block |
113 | * @octet **p@ = output pointer to free space |
114 | * |
115 | * Returns: Free buffer size. |
116 | * |
117 | * Use: Returns the free portion of a packet buffer. Data can then |
118 | * be written to this portion, and split out into packets by |
119 | * calling @pkbuf_flush@. |
120 | */ |
121 | |
122 | extern size_t pkbuf_free(pkbuf */*pk*/, octet **/*p*/); |
123 | |
124 | /* --- @pkbuf_snarf@ --- * |
125 | * |
126 | * Arguments: @pkbuf *pk@ = pointer to buffer block |
127 | * @const void *p@ = pointer to input data buffer |
128 | * @size_t sz@ = size of data in input buffer |
129 | * |
130 | * Returns: --- |
131 | * |
132 | * Use: Snarfs the data from the input buffer and spits it out as |
133 | * packets. This interface ignores the complexities of dealing |
134 | * with disablement: you should be using @pkbuf_free@ to |
135 | * contribute data if you want to cope with that. |
136 | */ |
137 | |
138 | extern void pkbuf_snarf(pkbuf */*pk*/, const void */*p*/, size_t /*sz*/); |
139 | |
140 | /* --- @pkbuf_want@ --- * |
141 | * |
142 | * Arguments: @pkbuf *pk@ = pointer to buffer block |
143 | * @size_t want@ = how many octets wanted for next packet |
144 | * |
145 | * Returns: --- |
146 | * |
147 | * Use: Sets the desired size for the next packet to be read. If |
148 | * it's larger than the current buffer, the buffer is extended. |
149 | */ |
150 | |
151 | extern void pkbuf_want(pkbuf */*pk*/, size_t /*want*/); |
152 | |
153 | /* --- @pkbuf_init@ --- * |
154 | * |
155 | * Arguments: @pkbuf *pk@ = pointer to buffer block |
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156 | * @pkbuf_func *func@ = handler function |
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157 | * @void *p@ = argument pointer for @func@ |
158 | * |
159 | * Returns: --- |
160 | * |
161 | * Use: Initializes a packet buffer block. Any packets are passed to |
162 | * the provided function for handling. |
163 | */ |
164 | |
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165 | extern void pkbuf_init(pkbuf */*pk*/, pkbuf_func */*func*/, void */*p*/); |
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166 | |
167 | /* --- @pkbuf_destroy@ --- * |
168 | * |
169 | * Arguments: @pkbuf *pk@ = pointer to buffer block |
170 | * |
171 | * Returns: --- |
172 | * |
173 | * Use: Deallocates a packet buffer and frees any resources it owned. |
174 | */ |
175 | |
176 | extern void pkbuf_destroy(pkbuf */*pk*/); |
177 | |
178 | /*----- That's all, folks -------------------------------------------------*/ |
179 | |
180 | #ifdef __cplusplus |
181 | } |
182 | #endif |
183 | |
184 | #endif |