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#if USE_POLL

struct rb_pollfdset {

int n_fds;

struct pollfd *fds;

};

static void

pollfdset_init(struct rb_pollfdset *pollfdset)

{

memset(pollfdset, 0, sizeof(*pollfdset));

}

static void

pollfdset_term(struct rb_pollfdset *pollfdset)

{

pollfdset->fds = xrealloc(pollfdset->fds, 0);

pollfdset->n_fds = 0;

}

static void

pollfdset_inc(struct rb_pollfdset *pollfdset)

{

pollfdset->fds = xrealloc(pollfdset->fds,sizeof(*pollfdset->fds) * (pollfdset->n_fds + 1));

memset(&pollfdset->fds[pollfdset->n_fds], 0, sizeof(*pollfdset->fds));

pollfdset->n_fds++;

}

static int

pollfdset_get_index(struct rb_pollfdset *pollfdset, int fd)

{

int i;

for (i = 0; i < pollfdset->n_fds ; i++)

if (pollfdset->fds[i].fd == fd)

return i;

return -1;

}

static int

pollfdset_index(struct rb_pollfdset *pollfdset, int fd)

{

int ret = pollfdset_get_index(pollfdset, fd);

if (ret < 0) {

ret = pollfdset->n_fds;

pollfdset_inc(pollfdset);

pollfdset->fds[ret].fd = fd;

}

return ret;

}

static void

pollfdset_set_flags(struct rb_pollfdset *pollfdset, int fd, int flags)

{

/* this is tricky - fds might get reallocated as a sideeffect of obtaining the index */

int idx = pollfdset_index(pollfdset, fd);

pollfdset->fds[idx].events |= flags;

}

static void

pollfdset_add(struct rb_pollfdset *pollfdset, rb_fdset_t *fds, int flags)

{

int i;

for (i = 0; i < fds->maxfd ; i++)

if (rb_fd_isset(i, fds))

pollfdset_set_flags(pollfdset, i, flags);

}

static void

pollfdset_extract(struct rb_pollfdset *pollfdset, rb_fdset_t *fds, int flags)

{

int i;

rb_fd_zero(fds);

for (i = 0; i < pollfdset->n_fds; i++)

if (pollfdset->fds[i].revents & (flags | POLLERR_SET))

rb_fd_set(pollfdset->fds[i].fd, fds);

}

int

rb_fd_select(int n, rb_fdset_t *readfds, rb_fdset_t *writefds, rb_fdset_t *exceptfds, rb_fdset_t *errorfds, struct timeval *timeout)

{

struct rb_pollfdset pollfdset;

int timeout_ms = timeout ? timeout->tv_sec * 1000 + timeout->tv_usec / 1000 : -1;

int ret;

pollfdset_init(&pollfdset);

if (readfds) pollfdset_add(&pollfdset, readfds, POLLIN_SET);

if (writefds) pollfdset_add(&pollfdset, writefds, POLLOUT_SET);

if (exceptfds) pollfdset_add(&pollfdset, exceptfds, POLLEX_SET);

if (errorfds) pollfdset_add(&pollfdset, errorfds, POLLERR_SET);

ret = poll(pollfdset.fds, pollfdset.n_fds, timeout_ms);

if (readfds) pollfdset_extract(&pollfdset, readfds, POLLIN_SET);

if (writefds) pollfdset_extract(&pollfdset, writefds, POLLOUT_SET);

if (exceptfds) pollfdset_extract(&pollfdset, exceptfds, POLLEX_SET);

if (errorfds) pollfdset_extract(&pollfdset, errorfds, POLLERR_SET);

pollfdset_term(&pollfdset);

return ret;

}

#else /* USE_POLL */

#endif /* USE_POLL */