Mirror of :pserver:anonymous@cvs.schmorp.de/schmorpforge libev http://software.schmorp.de/pkg/libev.html
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/*
* 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 (oev == nev)
return;
if (vec_max < (fd >> 5) + 1)
{
int new_max = (fd >> 5) + 1;
vec_ri = (unsigned char *)ev_realloc (vec_ri, new_max * 4);
vec_ro = (unsigned char *)ev_realloc (vec_ro, new_max * 4); /* could free/malloc */
vec_wi = (unsigned char *)ev_realloc (vec_wi, new_max * 4);
vec_wo = (unsigned char *)ev_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)
{
int word, offs;
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)
{
if (errno == EBADF)
fd_ebadf (EV_A);
else if (errno == ENOMEM && !syserr_cb)
fd_enomem (EV_A);
else if (errno != EINTR)
syserr ("(libev) select");
return;
}
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);
}
}
}
}
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;
vec_max = 0;
vec_ri = 0;
vec_ri = 0;
vec_wo = 0;
vec_wo = 0;
return EVMETHOD_SELECT;
}
static void
select_destroy (EV_P)
{
ev_free (vec_ri);
ev_free (vec_ro);
ev_free (vec_wi);
ev_free (vec_wo);
}