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[mLib] / selpk.c
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436fddaa 1/* -*-c-*-
2 *
8656dc50 3 * $Id: selpk.c,v 1.3 2004/04/08 01:36:13 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
436fddaa 30/*----- Header files ------------------------------------------------------*/
31
32#include <errno.h>
33#include <stdio.h>
34#include <stdlib.h>
35#include <string.h>
36
37#include <sys/types.h>
38#include <sys/time.h>
39#include <unistd.h>
40
41#include "pkbuf.h"
42#include "sel.h"
43#include "selpk.h"
44
45/*----- Main code ---------------------------------------------------------*/
46
47/* --- @selpk_enable@ --- *
48 *
49 * Arguments: @selpk *pk@ = pointer to buffer block
50 *
51 * Returns: ---
52 *
53 * Use: Enables a buffer for reading, and emits any queued packets
54 * to the buffer's owner.
55 */
56
57void selpk_enable(selpk *pk)
58{
59 if (!(pk->pk.f & PKBUF_ENABLE)) {
60 pk->pk.f |= PKBUF_ENABLE;
61 sel_addfile(&pk->reader);
62 pkbuf_flush(&pk->pk, 0, 0);
63 }
64}
65
66/* --- @selpk_disable@ --- *
67 *
68 * Arguments: @selpk *pk@ = pointer to a buffer block
69 *
70 * Returns: ---
71 *
72 * Use: Disables a buffer. It won't be read from until it's
73 * enabled again.
74 */
75
76void selpk_disable(selpk *pk)
77{
78 if (pk->pk.f & PKBUF_ENABLE) {
79 pk->pk.f &= ~PKBUF_ENABLE;
80 sel_rmfile(&pk->reader);
81 }
82}
83
84/* --- @selpk_read@ --- *
85 *
86 * Arguments: @int fd@ = file descriptor to read from
87 * @int mode@ = what we can do to the file
88 * @void *vp@ = pointer to buffer context
89 *
90 * Returns: ---
91 *
92 * Use: Acts on the result of a @select@ call.
93 */
94
95static void selpk_read(int fd, unsigned mode, void *vp)
96{
97 selpk *pk = vp;
98 octet *p;
99 size_t sz;
100 int n;
101
102 sz = pkbuf_free(&pk->pk, &p);
103 n = read(fd, p, sz);
104 if (n == 0)
105 pkbuf_close(&pk->pk);
106 else if (n > 0)
107 pkbuf_flush(&pk->pk, p, n);
108 else switch (errno) {
109 case EINTR:
110 case EAGAIN:
111#if EAGAIN != EWOULDBLOCK
112 case EWOULDBLOCK:
113#endif
114 return;
115 default:
116 pkbuf_close(&pk->pk);
117 }
118}
119
120/* --- @selpk_want@ --- *
121 *
122 * Arguments: @selpk *pk@ = pointer to buffer block
123 * @size_t sz@ = size of buffer
124 *
125 * Returns: ---
126 *
127 * Use: Sets the size of the packet to be read next.
128 */
129
130void selpk_want(selpk *pk, size_t sz)
131{
132 pkbuf_want(&pk->pk, sz);
133}
134
135/* --- @selpk_init@ --- *
136 *
137 * Arguments: @selpk *pk@ = pointer to buffer block
138 * @sel_state *s@ = pointer to select state to attach to
139 * @int fd@ = file descriptor to listen to
0daaeb18 140 * @pkbuf_func *func@ = function to call
436fddaa 141 * @void *p@ = argument for function
142 *
143 * Returns: ---
144 *
145 * Use: Initializes a buffer block.
146 */
147
0daaeb18 148void selpk_init(selpk *pk, sel_state *s, int fd, pkbuf_func *func, void *p)
436fddaa 149{
150 pkbuf_init(&pk->pk, func, p);
151 pk->pk.f &= ~PKBUF_ENABLE;
152 sel_initfile(s, &pk->reader, fd, SEL_READ, selpk_read, pk);
153 selpk_enable(pk);
154}
155
156/* --- @selpk_destroy@ --- *
157 *
158 * Arguments: @selpk *pk@ = pointer to buffer block
159 *
160 * Returns: ---
161 *
162 * Use: Deallocates a packet buffer and frees any resources it owned.
163 */
164
165void selpk_destroy(selpk *pk)
166{
167 selpk_disable(pk);
168 pkbuf_destroy(&pk->pk);
169}
170
171/*----- That's all, folks -------------------------------------------------*/