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/cvs/libev/ev_select.c
Revision: 1.6
Committed: Wed Oct 31 20:46:44 2007 UTC (16 years, 6 months ago) by root
Content type: text/plain
Branch: MAIN
Changes since 1.5: +4 -3 lines
Log Message:
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File Contents

# User Rev Content
1 root 1.4 /*
2     * Copyright (c) 2007 Marc Alexander Lehmann <libev@schmorp.de>
3     * All rights reserved.
4     *
5     * Redistribution and use in source and binary forms, with or without
6     * modification, are permitted provided that the following conditions are
7     * met:
8     *
9     * * Redistributions of source code must retain the above copyright
10     * notice, this list of conditions and the following disclaimer.
11     *
12     * * Redistributions in binary form must reproduce the above
13     * copyright notice, this list of conditions and the following
14     * disclaimer in the documentation and/or other materials provided
15     * with the distribution.
16     *
17     * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
18     * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
19     * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
20     * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
21     * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
22     * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
23     * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
24     * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
25     * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
26     * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
27     * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28     */
29    
30 root 1.2 /* for broken bsd's */
31     #include <sys/time.h>
32     #include <sys/types.h>
33     #include <unistd.h>
34    
35     /* for unix systems */
36     #include <sys/select.h>
37    
38     #include <string.h>
39     #include <inttypes.h>
40    
41     static unsigned char *vec_ri, *vec_ro, *vec_wi, *vec_wo;
42     static int vec_max;
43    
44     static void
45     select_modify (int fd, int oev, int nev)
46     {
47     int offs = fd >> 3;
48     int mask = 1 << (fd & 7);
49    
50     if (vec_max < (fd >> 5) + 1)
51     {
52 root 1.5 int new_max = (fd >> 5) + 1;
53 root 1.2
54 root 1.5 vec_ri = (unsigned char *)realloc (vec_ri, new_max * 4);
55     vec_ro = (unsigned char *)realloc (vec_ro, new_max * 4); /* could free/malloc */
56     vec_wi = (unsigned char *)realloc (vec_wi, new_max * 4);
57     vec_wo = (unsigned char *)realloc (vec_wo, new_max * 4); /* could free/malloc */
58    
59     for (; vec_max < new_max; ++vec_max)
60     ((uint32_t *)vec_ri)[vec_max] =
61     ((uint32_t *)vec_wi)[vec_max] = 0;
62 root 1.2 }
63    
64     vec_ri [offs] |= mask;
65     if (!(nev & EV_READ))
66     vec_ri [offs] &= ~mask;
67    
68     vec_wi [offs] |= mask;
69     if (!(nev & EV_WRITE))
70     vec_wi [offs] &= ~mask;
71     }
72    
73 root 1.6 static void
74     select_poll (ev_tstamp timeout)
75 root 1.2 {
76     struct timeval tv;
77     int res;
78    
79     memcpy (vec_ro, vec_ri, vec_max * 4);
80     memcpy (vec_wo, vec_wi, vec_max * 4);
81    
82     tv.tv_sec = (long)timeout;
83     tv.tv_usec = (long)((timeout - (ev_tstamp)tv.tv_sec) * 1e6);
84    
85     res = select (vec_max * 32, (fd_set *)vec_ro, (fd_set *)vec_wo, 0, &tv);
86    
87     if (res > 0)
88     {
89     int word, offs;
90    
91     for (word = vec_max; word--; )
92     {
93     if (((uint32_t *)vec_ro) [word] | ((uint32_t *)vec_wo) [word])
94     for (offs = 4; offs--; )
95     {
96     int idx = word * 4 + offs;
97     unsigned char byte_r = vec_ro [idx];
98     unsigned char byte_w = vec_wo [idx];
99     int bit;
100    
101     if (byte_r | byte_w)
102     for (bit = 8; bit--; )
103     {
104     int events = 0;
105     events |= byte_r & (1 << bit) ? EV_READ : 0;
106     events |= byte_w & (1 << bit) ? EV_WRITE : 0;
107    
108     if (events)
109     fd_event (idx * 8 + bit, events);
110     }
111     }
112     }
113     }
114 root 1.5 else if (res < 0)
115     {
116     if (errno == EBADF)
117     fd_recheck ();
118     }
119 root 1.2 }
120    
121 root 1.6 static void
122     select_init (int flags)
123 root 1.2 {
124 root 1.3 ev_method = EVMETHOD_SELECT;
125 root 1.2 method_fudge = 1e-2; /* needed to compensate for select returning early, very conservative */
126     method_modify = select_modify;
127     method_poll = select_poll;
128     }
129