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/cvs/libev/ev_select.c
Revision: 1.2
Committed: Tue Oct 30 23:54:38 2007 UTC (16 years, 6 months ago) by root
Content type: text/plain
Branch: MAIN
Changes since 1.1: +92 -0 lines
Log Message:
implement select method

File Contents

# Content
1 /* for broken bsd's */
2 #include <sys/time.h>
3 #include <sys/types.h>
4 #include <unistd.h>
5
6 /* for unix systems */
7 #include <sys/select.h>
8
9 #include <string.h>
10 #include <inttypes.h>
11
12 static unsigned char *vec_ri, *vec_ro, *vec_wi, *vec_wo;
13 static int vec_max;
14
15 static void
16 select_modify (int fd, int oev, int nev)
17 {
18 int offs = fd >> 3;
19 int mask = 1 << (fd & 7);
20
21 if (vec_max < (fd >> 5) + 1)
22 {
23 vec_max = (fd >> 5) + 1;
24
25 vec_ri = (unsigned char *)realloc (vec_ri, vec_max * 4);
26 vec_ro = (unsigned char *)realloc (vec_ro, vec_max * 4); /* could free/malloc */
27 vec_wi = (unsigned char *)realloc (vec_wi, vec_max * 4);
28 vec_wo = (unsigned char *)realloc (vec_wo, vec_max * 4); /* could free/malloc */
29 }
30
31 vec_ri [offs] |= mask;
32 if (!(nev & EV_READ))
33 vec_ri [offs] &= ~mask;
34
35 vec_wi [offs] |= mask;
36 if (!(nev & EV_WRITE))
37 vec_wi [offs] &= ~mask;
38 }
39
40 static void select_poll (ev_tstamp timeout)
41 {
42 struct timeval tv;
43 int res;
44
45 memcpy (vec_ro, vec_ri, vec_max * 4);
46 memcpy (vec_wo, vec_wi, vec_max * 4);
47
48 tv.tv_sec = (long)timeout;
49 tv.tv_usec = (long)((timeout - (ev_tstamp)tv.tv_sec) * 1e6);
50
51 res = select (vec_max * 32, (fd_set *)vec_ro, (fd_set *)vec_wo, 0, &tv);
52
53 if (res > 0)
54 {
55 int word, offs;
56
57 for (word = vec_max; word--; )
58 {
59 if (((uint32_t *)vec_ro) [word] | ((uint32_t *)vec_wo) [word])
60 for (offs = 4; offs--; )
61 {
62 int idx = word * 4 + offs;
63 unsigned char byte_r = vec_ro [idx];
64 unsigned char byte_w = vec_wo [idx];
65 int bit;
66
67 if (byte_r | byte_w)
68 for (bit = 8; bit--; )
69 {
70 int events = 0;
71 events |= byte_r & (1 << bit) ? EV_READ : 0;
72 events |= byte_w & (1 << bit) ? EV_WRITE : 0;
73
74 if (events)
75 fd_event (idx * 8 + bit, events);
76 }
77 }
78 }
79 }
80 }
81
82 int select_init (int flags)
83 {
84 ev_method = EVMETHOD_SELECT;
85 method_fudge = 1e-2; /* needed to compensate for select returning early, very conservative */
86 method_modify = select_modify;
87 method_poll = select_poll;
88
89 return 1;
90 }
91
92