3 * $Id: pkbuf.h,v 1.5 2004/04/08 01:36:13 mdw Exp $
5 * Simple packet buffering
7 * (c) 2000 Straylight/Edgeware
10 /*----- Licensing notice --------------------------------------------------*
12 * This file is part of the mLib utilities library.
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.
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.
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,
37 /*----- Header files ------------------------------------------------------*/
49 /*----- Data structures ---------------------------------------------------*/
53 typedef void pkbuf_func(octet */*b*/, size_t /*sz*/,
54 struct pkbuf */*pk*/, size_t */*keep*/,
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 */
62 pkbuf_func *func; /* Handler function */
63 void *p; /* Argument for handler */
64 arena *a; /* Memory allocation arena */
65 octet *buf; /* Actual buffer space */
68 #define PKBUF_ENABLE 1u /* Buffer is currently enabled */
69 #define PKBUF_CLOSE 2u /* Buffer is now closed */
71 /*----- Functions provided ------------------------------------------------*/
73 /* --- @pkbuf_flush@ --- *
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
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
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
96 extern void pkbuf_flush(pkbuf */*pk*/, octet */*p*/, size_t /*len*/);
98 /* --- @pkbuf_close@ --- *
100 * Arguments: @pkbuf *pk@ = pointer to buffer block
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.
108 extern void pkbuf_close(pkbuf */*pk*/);
110 /* --- @pkbuf_free@ --- *
112 * Arguments: @pkbuf *pk@ = pointer to buffer block
113 * @octet **p@ = output pointer to free space
115 * Returns: Free buffer size.
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@.
122 extern size_t pkbuf_free(pkbuf */*pk*/, octet **/*p*/);
124 /* --- @pkbuf_snarf@ --- *
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
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.
138 extern void pkbuf_snarf(pkbuf */*pk*/, const void */*p*/, size_t /*sz*/);
140 /* --- @pkbuf_want@ --- *
142 * Arguments: @pkbuf *pk@ = pointer to buffer block
143 * @size_t want@ = how many octets wanted for next packet
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.
151 extern void pkbuf_want(pkbuf */*pk*/, size_t /*want*/);
153 /* --- @pkbuf_init@ --- *
155 * Arguments: @pkbuf *pk@ = pointer to buffer block
156 * @pkbuf_func *func@ = handler function
157 * @void *p@ = argument pointer for @func@
161 * Use: Initializes a packet buffer block. Any packets are passed to
162 * the provided function for handling.
165 extern void pkbuf_init(pkbuf */*pk*/, pkbuf_func */*func*/, void */*p*/);
167 /* --- @pkbuf_destroy@ --- *
169 * Arguments: @pkbuf *pk@ = pointer to buffer block
173 * Use: Deallocates a packet buffer and frees any resources it owned.
176 extern void pkbuf_destroy(pkbuf */*pk*/);
178 /*----- That's all, folks -------------------------------------------------*/