3 * $Id: pkbuf.h,v 1.4 2002/01/13 13:33:51 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,
30 /*----- Revision history --------------------------------------------------*
33 * Revision 1.4 2002/01/13 13:33:51 mdw
34 * Packet handler functions now have a @typedef@ name.
36 * Revision 1.3 2001/02/03 16:23:33 mdw
37 * Bug fix: handle a disable during a close-induced flush without dumping
40 * Revision 1.2 2001/01/20 12:06:01 mdw
41 * Define flags with macros, to ensure unsignedness.
43 * Revision 1.1 2000/06/17 10:39:19 mdw
44 * Experimental new support for packet buffering.
55 /*----- Header files ------------------------------------------------------*/
67 /*----- Data structures ---------------------------------------------------*/
71 typedef void pkbuf_func(octet */
*b*/
, size_t /*sz*/,
72 struct pkbuf */
*pk*/
, size_t */
*keep*/
,
75 typedef struct pkbuf
{
76 size_t sz
; /* Size of current buffer */
77 size_t len
; /* Length of data in the buffer */
78 size_t want
; /* Want this many bytes for packet */
79 unsigned f
; /* Various state flags */
80 pkbuf_func
*func
; /* Handler function */
81 void *p
; /* Argument for handler */
82 arena
*a
; /* Memory allocation arena */
83 octet
*buf
; /* Actual buffer space */
86 #define PKBUF_ENABLE 1u /* Buffer is currently enabled */
87 #define PKBUF_CLOSE 2u /* Buffer is now closed */
89 /*----- Functions provided ------------------------------------------------*/
91 /* --- @pkbuf_flush@ --- *
93 * Arguments: @pkbuf *pk@ = pointer to buffer block
94 * @octet *p@ = pointer to where to start searching
95 * @size_t len@ = length of new material added
99 * Use: Flushes any complete packets in a packet buffer. New
100 * material is assumed to have been added starting at @p@. If
101 * @p@ is null, then the scan starts at the beginning of the
102 * buffer, and the size of data already in the buffer is used in
105 * It is assumed that the buffer is initially enabled. You
106 * shouldn't be contributing data to a disabled buffer anyway.
107 * However, the buffer handler may at some point disable itself,
108 * and @pkbuf_flush@ can cope with this eventuality. Any
109 * pending data is left at the start of the buffer and can be
110 * flushed out by calling @pkbuf_flush(b, 0, 0)@ if the buffer
111 * is ever re-enabled.
114 extern void pkbuf_flush(pkbuf */
*pk*/
, octet */
*p*/
, size_t /*len*/);
116 /* --- @pkbuf_close@ --- *
118 * Arguments: @pkbuf *pk@ = pointer to buffer block
122 * Use: Informs the client that no more data is likely to arrive. If
123 * there is a partial packet in the buffer, it is discarded.
126 extern void pkbuf_close(pkbuf */
*pk*/
);
128 /* --- @pkbuf_free@ --- *
130 * Arguments: @pkbuf *pk@ = pointer to buffer block
131 * @octet **p@ = output pointer to free space
133 * Returns: Free buffer size.
135 * Use: Returns the free portion of a packet buffer. Data can then
136 * be written to this portion, and split out into packets by
137 * calling @pkbuf_flush@.
140 extern size_t pkbuf_free(pkbuf */
*pk*/
, octet
**/
*p*/
);
142 /* --- @pkbuf_snarf@ --- *
144 * Arguments: @pkbuf *pk@ = pointer to buffer block
145 * @const void *p@ = pointer to input data buffer
146 * @size_t sz@ = size of data in input buffer
150 * Use: Snarfs the data from the input buffer and spits it out as
151 * packets. This interface ignores the complexities of dealing
152 * with disablement: you should be using @pkbuf_free@ to
153 * contribute data if you want to cope with that.
156 extern void pkbuf_snarf(pkbuf */
*pk*/
, const void */
*p*/
, size_t /*sz*/);
158 /* --- @pkbuf_want@ --- *
160 * Arguments: @pkbuf *pk@ = pointer to buffer block
161 * @size_t want@ = how many octets wanted for next packet
165 * Use: Sets the desired size for the next packet to be read. If
166 * it's larger than the current buffer, the buffer is extended.
169 extern void pkbuf_want(pkbuf */
*pk*/
, size_t /*want*/);
171 /* --- @pkbuf_init@ --- *
173 * Arguments: @pkbuf *pk@ = pointer to buffer block
174 * @pkbuf_func *func@ = handler function
175 * @void *p@ = argument pointer for @func@
179 * Use: Initializes a packet buffer block. Any packets are passed to
180 * the provided function for handling.
183 extern void pkbuf_init(pkbuf */
*pk*/
, pkbuf_func */
*func*/
, void */
*p*/
);
185 /* --- @pkbuf_destroy@ --- *
187 * Arguments: @pkbuf *pk@ = pointer to buffer block
191 * Use: Deallocates a packet buffer and frees any resources it owned.
194 extern void pkbuf_destroy(pkbuf */
*pk*/
);
196 /*----- That's all, folks -------------------------------------------------*/