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[mLib] / selpk.c
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436fddaa 1/* -*-c-*-
2 *
0daaeb18 3 * $Id: selpk.c,v 1.2 2002/01/13 13:33:51 mdw Exp $
436fddaa 4 *
5 * Packet-buffering select handler
6 *
7 * (c) 1999 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: selpk.c,v $
0daaeb18 33 * Revision 1.2 2002/01/13 13:33:51 mdw
34 * Packet handler functions now have a @typedef@ name.
35 *
436fddaa 36 * Revision 1.1 2000/06/17 10:39:19 mdw
37 * Experimental new support for packet buffering.
38 *
39 */
40
41/*----- Header files ------------------------------------------------------*/
42
43#include <errno.h>
44#include <stdio.h>
45#include <stdlib.h>
46#include <string.h>
47
48#include <sys/types.h>
49#include <sys/time.h>
50#include <unistd.h>
51
52#include "pkbuf.h"
53#include "sel.h"
54#include "selpk.h"
55
56/*----- Main code ---------------------------------------------------------*/
57
58/* --- @selpk_enable@ --- *
59 *
60 * Arguments: @selpk *pk@ = pointer to buffer block
61 *
62 * Returns: ---
63 *
64 * Use: Enables a buffer for reading, and emits any queued packets
65 * to the buffer's owner.
66 */
67
68void selpk_enable(selpk *pk)
69{
70 if (!(pk->pk.f & PKBUF_ENABLE)) {
71 pk->pk.f |= PKBUF_ENABLE;
72 sel_addfile(&pk->reader);
73 pkbuf_flush(&pk->pk, 0, 0);
74 }
75}
76
77/* --- @selpk_disable@ --- *
78 *
79 * Arguments: @selpk *pk@ = pointer to a buffer block
80 *
81 * Returns: ---
82 *
83 * Use: Disables a buffer. It won't be read from until it's
84 * enabled again.
85 */
86
87void selpk_disable(selpk *pk)
88{
89 if (pk->pk.f & PKBUF_ENABLE) {
90 pk->pk.f &= ~PKBUF_ENABLE;
91 sel_rmfile(&pk->reader);
92 }
93}
94
95/* --- @selpk_read@ --- *
96 *
97 * Arguments: @int fd@ = file descriptor to read from
98 * @int mode@ = what we can do to the file
99 * @void *vp@ = pointer to buffer context
100 *
101 * Returns: ---
102 *
103 * Use: Acts on the result of a @select@ call.
104 */
105
106static void selpk_read(int fd, unsigned mode, void *vp)
107{
108 selpk *pk = vp;
109 octet *p;
110 size_t sz;
111 int n;
112
113 sz = pkbuf_free(&pk->pk, &p);
114 n = read(fd, p, sz);
115 if (n == 0)
116 pkbuf_close(&pk->pk);
117 else if (n > 0)
118 pkbuf_flush(&pk->pk, p, n);
119 else switch (errno) {
120 case EINTR:
121 case EAGAIN:
122#if EAGAIN != EWOULDBLOCK
123 case EWOULDBLOCK:
124#endif
125 return;
126 default:
127 pkbuf_close(&pk->pk);
128 }
129}
130
131/* --- @selpk_want@ --- *
132 *
133 * Arguments: @selpk *pk@ = pointer to buffer block
134 * @size_t sz@ = size of buffer
135 *
136 * Returns: ---
137 *
138 * Use: Sets the size of the packet to be read next.
139 */
140
141void selpk_want(selpk *pk, size_t sz)
142{
143 pkbuf_want(&pk->pk, sz);
144}
145
146/* --- @selpk_init@ --- *
147 *
148 * Arguments: @selpk *pk@ = pointer to buffer block
149 * @sel_state *s@ = pointer to select state to attach to
150 * @int fd@ = file descriptor to listen to
0daaeb18 151 * @pkbuf_func *func@ = function to call
436fddaa 152 * @void *p@ = argument for function
153 *
154 * Returns: ---
155 *
156 * Use: Initializes a buffer block.
157 */
158
0daaeb18 159void selpk_init(selpk *pk, sel_state *s, int fd, pkbuf_func *func, void *p)
436fddaa 160{
161 pkbuf_init(&pk->pk, func, p);
162 pk->pk.f &= ~PKBUF_ENABLE;
163 sel_initfile(s, &pk->reader, fd, SEL_READ, selpk_read, pk);
164 selpk_enable(pk);
165}
166
167/* --- @selpk_destroy@ --- *
168 *
169 * Arguments: @selpk *pk@ = pointer to buffer block
170 *
171 * Returns: ---
172 *
173 * Use: Deallocates a packet buffer and frees any resources it owned.
174 */
175
176void selpk_destroy(selpk *pk)
177{
178 selpk_disable(pk);
179 pkbuf_destroy(&pk->pk);
180}
181
182/*----- That's all, folks -------------------------------------------------*/