libev/ev_select.c

/*
 * Copyright (c) 2007 Marc Alexander Lehmann <libev@schmorp.de>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 *
 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *
 *     * Redistributions in binary form must reproduce the above
 *       copyright notice, this list of conditions and the following
 *       disclaimer in the documentation and/or other materials provided
 *       with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/* for broken bsd's */
#include <sys/time.h>
#include <sys/types.h>
#include <unistd.h>

/* for unix systems */
#include <sys/select.h>

#include <string.h>
#include <inttypes.h>

static unsigned char *vec_ri, *vec_ro, *vec_wi, *vec_wo;
static int vec_max;

static void
select_modify (int fd, int oev, int nev)
{
  int offs = fd >> 3;
  int mask = 1 << (fd & 7);

  if (vec_max < (fd >> 5) + 1)
    {
      int new_max = (fd >> 5) + 1;

      vec_ri = (unsigned char *)realloc (vec_ri, new_max * 4);
      vec_ro = (unsigned char *)realloc (vec_ro, new_max * 4); /* could free/malloc */
      vec_wi = (unsigned char *)realloc (vec_wi, new_max * 4);
      vec_wo = (unsigned char *)realloc (vec_wo, new_max * 4); /* could free/malloc */

      for (; vec_max < new_max; ++vec_max)
        ((uint32_t *)vec_ri)[vec_max] =
        ((uint32_t *)vec_wi)[vec_max] = 0;
    }

  vec_ri [offs] |= mask;
  if (!(nev & EV_READ))
    vec_ri [offs] &= ~mask;

  vec_wi [offs] |= mask;
  if (!(nev & EV_WRITE))
    vec_wi [offs] &= ~mask;
}

static void select_poll (ev_tstamp timeout)
{
  struct timeval tv;
  int res;

  memcpy (vec_ro, vec_ri, vec_max * 4);
  memcpy (vec_wo, vec_wi, vec_max * 4);

  tv.tv_sec  = (long)timeout;
  tv.tv_usec = (long)((timeout - (ev_tstamp)tv.tv_sec) * 1e6);

  res = select (vec_max * 32, (fd_set *)vec_ro, (fd_set *)vec_wo, 0, &tv);

  if (res > 0)
    {
      int word, offs;

      for (word = vec_max; word--; )
        {
          if (((uint32_t *)vec_ro) [word] | ((uint32_t *)vec_wo) [word])
            for (offs = 4; offs--; )
              {
                int idx = word * 4 + offs;
                unsigned char byte_r = vec_ro [idx];
                unsigned char byte_w = vec_wo [idx];
                int bit;

                if (byte_r | byte_w)
                  for (bit = 8; bit--; )
                    {
                      int events = 0;
                      events |= byte_r & (1 << bit) ? EV_READ  : 0;
                      events |= byte_w & (1 << bit) ? EV_WRITE : 0;

                      if (events)
                        fd_event (idx * 8 + bit, events);
                    }
              }
        }
    }
  else if (res < 0)
    {
      if (errno == EBADF)
        fd_recheck ();
    }
}

void select_init (int flags)
{
  ev_method     = EVMETHOD_SELECT;
  method_fudge  = 1e-2; /* needed to compensate for select returning early, very conservative */
  method_modify = select_modify;
  method_poll   = select_poll;
}


Revision:	1.5
Committed:	Wed Oct 31 17:55:55 2007 UTC (16 years, 6 months ago) by root
Content type:	text/plain
Branch:	MAIN
Changes since 1.4:	+14 -5 lines
Log Message:	beginners mistake
#	Content
1	/*
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	/* 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	int new_max = (fd >> 5) + 1;
53
54	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	}
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	static void select_poll (ev_tstamp timeout)
74	{
75	struct timeval tv;
76	int res;
77
78	memcpy (vec_ro, vec_ri, vec_max * 4);
79	memcpy (vec_wo, vec_wi, vec_max * 4);
80
81	tv.tv_sec = (long)timeout;
82	tv.tv_usec = (long)((timeout - (ev_tstamp)tv.tv_sec) * 1e6);
83
84	res = select (vec_max * 32, (fd_set )vec_ro, (fd_set )vec_wo, 0, &tv);
85
86	if (res > 0)
87	{
88	int word, offs;
89
90	for (word = vec_max; word--; )
91	{
92	if (((uint32_t )vec_ro) [word] \| ((uint32_t )vec_wo) [word])
93	for (offs = 4; offs--; )
94	{
95	int idx = word * 4 + offs;
96	unsigned char byte_r = vec_ro [idx];
97	unsigned char byte_w = vec_wo [idx];
98	int bit;
99
100	if (byte_r \| byte_w)
101	for (bit = 8; bit--; )
102	{
103	int events = 0;
104	events \|= byte_r & (1 << bit) ? EV_READ : 0;
105	events \|= byte_w & (1 << bit) ? EV_WRITE : 0;
106
107	if (events)
108	fd_event (idx * 8 + bit, events);
109	}
110	}
111	}
112	}
113	else if (res < 0)
114	{
115	if (errno == EBADF)
116	fd_recheck ();
117	}
118	}
119
120	void select_init (int flags)
121	{
122	ev_method = EVMETHOD_SELECT;
123	method_fudge = 1e-2; /* needed to compensate for select returning early, very conservative */
124	method_modify = select_modify;
125	method_poll = select_poll;
126	}
127
128