libev/ev_select.c

/*
 * libev select fd activity backend
 *
 * 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 */
#ifndef WIN32
# include <sys/select.h>
#endif

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

static void
select_modify (EV_P_ 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_P_ 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 (EV_A_ idx * 8 + bit, events);
                    }
              }
        }
    }
  else if (res < 0)
    {
      if (errno == EBADF)
        fd_ebadf (EV_A);
      else if (errno == ENOMEM)
        fd_enomem (EV_A);
    }
}

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

  return EVMETHOD_SELECT;
}

Revision:	1.11
Committed:	Sun Nov 4 00:24:17 2007 UTC (16 years, 6 months ago) by root
Content type:	text/plain
Branch:	MAIN
Changes since 1.10:	+3 -3 lines
Log Message:	wow the event api is broken
#	User	Rev	Content
1	root	1.4	/*
2	root	1.7	* libev select fd activity backend
3			*
4	root	1.4	* Copyright (c) 2007 Marc Alexander Lehmann <libev@schmorp.de>
5			* All rights reserved.
6			*
7			* Redistribution and use in source and binary forms, with or without
8			* modification, are permitted provided that the following conditions are
9			* met:
10			*
11			* * Redistributions of source code must retain the above copyright
12			* notice, this list of conditions and the following disclaimer.
13			*
14			* * Redistributions in binary form must reproduce the above
15			* copyright notice, this list of conditions and the following
16			* disclaimer in the documentation and/or other materials provided
17			* with the distribution.
18			*
19			* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
20			* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
21			* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
22			* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
23			* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
24			* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
25			* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
26			* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
27			* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
28			* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
29			* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
30			*/
31
32	root	1.2	/* for broken bsd's */
33			#include <sys/time.h>
34			#include <sys/types.h>
35			#include <unistd.h>
36
37			/* for unix systems */
38	root	1.9	#ifndef WIN32
39			# include <sys/select.h>
40			#endif
41	root	1.2
42			#include <string.h>
43			#include <inttypes.h>
44
45			static void
46	root	1.10	select_modify (EV_P_ int fd, int oev, int nev)
47	root	1.2	{
48			int offs = fd >> 3;
49			int mask = 1 << (fd & 7);
50
51			if (vec_max < (fd >> 5) + 1)
52			{
53	root	1.5	int new_max = (fd >> 5) + 1;
54	root	1.2
55	root	1.5	vec_ri = (unsigned char )realloc (vec_ri, new_max 4);
56			vec_ro = (unsigned char )realloc (vec_ro, new_max 4); /* could free/malloc */
57			vec_wi = (unsigned char )realloc (vec_wi, new_max 4);
58			vec_wo = (unsigned char )realloc (vec_wo, new_max 4); /* could free/malloc */
59
60			for (; vec_max < new_max; ++vec_max)
61			((uint32_t *)vec_ri)[vec_max] =
62			((uint32_t *)vec_wi)[vec_max] = 0;
63	root	1.2	}
64
65			vec_ri [offs] \|= mask;
66			if (!(nev & EV_READ))
67			vec_ri [offs] &= ~mask;
68
69			vec_wi [offs] \|= mask;
70			if (!(nev & EV_WRITE))
71			vec_wi [offs] &= ~mask;
72			}
73
74	root	1.6	static void
75	root	1.10	select_poll (EV_P_ ev_tstamp timeout)
76	root	1.2	{
77			struct timeval tv;
78			int res;
79
80			memcpy (vec_ro, vec_ri, vec_max * 4);
81			memcpy (vec_wo, vec_wi, vec_max * 4);
82
83			tv.tv_sec = (long)timeout;
84			tv.tv_usec = (long)((timeout - (ev_tstamp)tv.tv_sec) * 1e6);
85
86			res = select (vec_max * 32, (fd_set )vec_ro, (fd_set )vec_wo, 0, &tv);
87
88			if (res > 0)
89			{
90			int word, offs;
91
92			for (word = vec_max; word--; )
93			{
94			if (((uint32_t )vec_ro) [word] \| ((uint32_t )vec_wo) [word])
95			for (offs = 4; offs--; )
96			{
97			int idx = word * 4 + offs;
98			unsigned char byte_r = vec_ro [idx];
99			unsigned char byte_w = vec_wo [idx];
100			int bit;
101
102			if (byte_r \| byte_w)
103			for (bit = 8; bit--; )
104			{
105			int events = 0;
106			events \|= byte_r & (1 << bit) ? EV_READ : 0;
107			events \|= byte_w & (1 << bit) ? EV_WRITE : 0;
108
109			if (events)
110	root	1.11	fd_event (EV_A_ idx * 8 + bit, events);
111	root	1.2	}
112			}
113			}
114			}
115	root	1.5	else if (res < 0)
116			{
117			if (errno == EBADF)
118	root	1.11	fd_ebadf (EV_A);
119	root	1.8	else if (errno == ENOMEM)
120	root	1.11	fd_enomem (EV_A);
121	root	1.5	}
122	root	1.2	}
123
124	root	1.10	static int
125			select_init (EV_P_ int flags)
126	root	1.2	{
127			method_fudge = 1e-2; /* needed to compensate for select returning early, very conservative */
128			method_modify = select_modify;
129			method_poll = select_poll;
130	root	1.10
131			return EVMETHOD_SELECT;
132	root	1.2	}
133