ncursesw-morphos/ncurses/tty/lib_twait.c

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/****************************************************************************
 *  Author: Zeyd M. Ben-Halim <zmbenhal@netcom.com> 1992,1995               *
 *     and: Eric S. Raymond <esr@snark.thyrsus.com>                         *
 ****************************************************************************/

/*
**	lib_twait.c
**
**	The routine _nc_timed_wait().
**
**	(This file was originally written by Eric Raymond; however except for
**	comments, none of the original code remains - T.Dickey).
*/

#ifdef __BEOS__
#include <OS.h>
#endif

#include <curses.priv.h>

#if USE_FUNC_POLL
# if HAVE_SYS_TIME_H
#  include <sys/time.h>
# endif
#elif HAVE_SELECT
# if HAVE_SYS_TIME_H && HAVE_SYS_TIME_SELECT
#  include <sys/time.h>
# endif
# if HAVE_SYS_SELECT_H
#  include <sys/select.h>
# endif
#endif

MODULE_ID("$Id: lib_twait.c,v 1.37 2000/06/29 23:03:09 tom Exp $")

static long _nc_gettime(bool first)
{
	long res;

#if HAVE_GETTIMEOFDAY
# define PRECISE_GETTIME 1
	static struct timeval t0;
	struct timeval t1;
	gettimeofday(&t1, (struct timezone *)0);
	if (first) {
		t0 = t1;
	}
	res = (t1.tv_sec  - t0.tv_sec)  * 1000
	    + (t1.tv_usec - t0.tv_usec) / 1000;
#else
# define PRECISE_GETTIME 0
	static time_t t0;
	time_t t1 = time((time_t*)0);
	if (first) {
		t0 = t1;
	}
	res = (t1 - t0) * 1000;
#endif
	T(("%s time: %ld msec", first ? "get" : "elapsed", res));
	return res;
}

/*
 * Wait a specified number of milliseconds, returning nonzero if the timer
 * didn't expire before there is activity on the specified file descriptors.
 * The file-descriptors are specified by the mode:
 *	0 - none (absolute time)
 *	1 - ncurses' normal input-descriptor
 *	2 - mouse descriptor, if any
 *	3 - either input or mouse.
 * We return a mask that corresponds to the mode (e.g., 2 for mouse activity).
 *
 * If the milliseconds given are -1, the wait blocks until activity on the
 * descriptors.
 */
int _nc_timed_wait(int mode, int milliseconds, int *timeleft)
{
int	fd;
int	count;

int result;

#if USE_FUNC_POLL
struct pollfd fds[2];
#elif defined(__BEOS__)
#elif HAVE_SELECT
static fd_set set;
#endif

long starttime, returntime;

	T(("start twait: %d milliseconds, mode: %d", milliseconds, mode));

#if PRECISE_GETTIME
retry:
#endif
	starttime = _nc_gettime(TRUE);

	count = 0;

#if USE_FUNC_POLL
	if (mode & 1) {
		fds[count].fd     = SP->_ifd;
		fds[count].events = POLLIN;
		count++;
	}
	if ((mode & 2)
	 && (fd = SP->_mouse_fd) >= 0) {
		fds[count].fd     = fd;
		fds[count].events = POLLIN;
		count++;
	}
	result = poll(fds, count, milliseconds);

#elif defined(__BEOS__)
	/*
	 * BeOS's select() is declared in socket.h, so the configure script does
	 * not see it.  That's just as well, since that function works only for
	 * sockets.  This (using snooze and ioctl) was distilled from Be's patch
	 * for ncurses which uses a separate thread to simulate select().
	 *
	 * FIXME: the return values from the ioctl aren't very clear if we get
	 * interrupted.
	 */
	result = 0;
	if (mode & 1) {
		bigtime_t d;
		bigtime_t useconds = milliseconds * 1000;
		int n, howmany;

		if (useconds == 0) /* we're here to go _through_ the loop */
			useconds = 1;

		for (d = 0; d < useconds; d += 5000) {
			n = 0;
			howmany = ioctl(0, 'ichr', &n);
			if (howmany >= 0 && n > 0) {
				result = 1;
				break;
			}
			if (useconds > 1)
				snooze(5000);
			milliseconds -= 5;
		}
	} else if (milliseconds > 0) {
		snooze(milliseconds * 1000);
		milliseconds = 0;
	}
#elif HAVE_SELECT
	/*
	 * select() modifies the fd_set arguments; do this in the
	 * loop.
	 */
	FD_ZERO(&set);

	if (mode & 1) {
		FD_SET(SP->_ifd, &set);
		count = SP->_ifd + 1;
	}
	if ((mode & 2)
	 && (fd = SP->_mouse_fd) >= 0) {
		FD_SET(fd, &set);
		count = max(fd, count) + 1;
	}

	if (milliseconds >= 0) {
		struct timeval ntimeout;
		ntimeout.tv_sec  = milliseconds / 1000;
		ntimeout.tv_usec = (milliseconds % 1000) * 1000;
		result = select(count, &set, NULL, NULL, &ntimeout);
	} else {
		result = select(count, &set, NULL, NULL, NULL);
	}
#endif

	returntime = _nc_gettime(FALSE);

	if (milliseconds >= 0)
		milliseconds -= (returntime - starttime);

#if PRECISE_GETTIME
	/*
	 * If the timeout hasn't expired, and we've gotten no data,
	 * this is probably a system where 'select()' needs to be left
	 * alone so that it can complete.  Make this process sleep,
	 * then come back for more.
	 */
	if (result == 0 && milliseconds > 100) {
		napms(100);
		milliseconds -= 100;
		goto retry;
	}
#endif

	/* return approximate time left in milliseconds */
	if (timeleft)
		*timeleft = milliseconds;

	T(("end twait: returned %d (%d), remaining time %d msec",
		result, errno, milliseconds));

	/*
	 * Both 'poll()' and 'select()' return the number of file descriptors
	 * that are active.  Translate this back to the mask that denotes which
	 * file-descriptors, so that we don't need all of this system-specific
	 * code everywhere.
	 */
	if (result != 0) {
		if (result > 0) {
			result = 0;
#if USE_FUNC_POLL
			for (count = 0; count < 2; count++) {
				if ((mode & (1 << count))
				 && (fds[count].revents & POLLIN)) {
					result |= (1 << count);
				}
			}
#elif defined(__BEOS__)
			result = 1;	/* redundant, but simple */
#elif HAVE_SELECT
			if ((mode & 2)
			 && (fd = SP->_mouse_fd) >= 0
			 && FD_ISSET(fd, &set))
				result |= 2;
			if ((mode & 1)
			 && FD_ISSET(SP->_ifd, &set))
				result |= 1;
#endif
		}
		else
			result = 0;
	}

	return (result);
}