/*	$OpenBSD: lib_twait.c,v 1.3 1997/12/03 05:21:38 millert Exp $	*/


/***************************************************************************
*                            COPYRIGHT NOTICE                              *
****************************************************************************
*                ncurses is copyright (C) 1992-1995                        *
*                          Zeyd M. Ben-Halim                               *
*                          zmbenhal@netcom.com                             *
*                          Eric S. Raymond                                 *
*                          esr@snark.thyrsus.com                           *
*                                                                          *
*        Permission is hereby granted to reproduce and distribute ncurses  *
*        by any means and for any fee, whether alone or as part of a       *
*        larger distribution, in source or in binary form, PROVIDED        *
*        this notice is included with any such distribution, and is not    *
*        removed from any of its header files. Mention of ncurses in any   *
*        applications linked with it is highly appreciated.                *
*                                                                          *
*        ncurses comes AS IS with no warranty, implied or expressed.       *
*                                                                          *
***************************************************************************/

/*
**	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).
*/

#include <curses.priv.h>

#if USE_FUNC_POLL
#include <stropts.h>
#include <poll.h>
#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 1.26 1997/11/30 01:09:23 tom Exp $")

/*
 * We want to define GOOD_SELECT if the last argument of select(2) is
 * modified to indicate time left.  The code will deal gracefully with
 * the other case, this is just an optimization to reduce the number
 * of system calls per input event.
 *
 * In general, expect System-V-like UNIXes to have this behavior and BSD-like
 * ones to not have it.  Check your manual page.  If it doesn't explicitly
 * say the last argument is modified, assume it's not.
 *
 * (We'd really like configure to autodetect this, but writing a proper test
 * turns out to be hard.)
 */

#if HAVE_GETTIMEOFDAY
#if (defined(TRACE) && !HAVE_USLEEP) || ! GOOD_SELECT
static void _nc_gettime(struct timeval *tp)
{
	gettimeofday(tp, (struct timezone *)0);
	T(("time: %ld.%06ld", (long) tp->tv_sec, (long) tp->tv_usec));
}
#endif
#endif

#if !HAVE_USLEEP
int _nc_usleep(unsigned int usec)
{
int code;
struct timeval tval;

#if defined(TRACE) && HAVE_GETTIMEOFDAY
	_nc_gettime(&tval);
#endif
#if USE_FUNC_POLL
	{
	struct pollfd fds[1];
	code = poll(fds, 0, usec / 1000);
	}
#elif HAVE_SELECT
	tval.tv_sec = usec / 1000000;
	tval.tv_usec = usec % 1000000;
	code = select(0, NULL, NULL, NULL, &tval);
#endif

#if defined(TRACE) && HAVE_GETTIMEOFDAY
	_nc_gettime(&tval);
#endif
	return code;
}
#endif /* !HAVE_USLEEP */

/*
 * 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 = 0;
long	whole_secs = milliseconds / 1000;
long	micro_secs = (milliseconds % 1000) * 1000;

int result = 0;
struct timeval ntimeout;

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

#if !GOOD_SELECT && HAVE_GETTIMEOFDAY
struct timeval starttime, returntime;
long delta;

	_nc_gettime(&starttime);
#endif

	if (milliseconds >= 0) {
		ntimeout.tv_sec  = whole_secs;
		ntimeout.tv_usec = micro_secs;
	} else {
		ntimeout.tv_sec  = 0;
		ntimeout.tv_usec = 0;
	}

	T(("start twait: %lu.%06lu secs", (long) ntimeout.tv_sec, (long) ntimeout.tv_usec));

#ifdef HIDE_EINTR
	/*
	 * The do loop tries to make it look like we have restarting signals,
	 * even if we don't.
	 */
	do {
#endif /* HIDE_EINTR */
#if !GOOD_SELECT && HAVE_GETTIMEOFDAY
	retry:
#endif
		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 HAVE_SELECT
		/*
		 * Some systems modify 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;
		}

		errno = 0;
		result = select(count, &set, NULL, NULL, milliseconds >= 0 ? &ntimeout : 0);
#endif

#if !GOOD_SELECT && HAVE_GETTIMEOFDAY
		_nc_gettime(&returntime);

		/* The contents of ntimeout aren't guaranteed after return from
		 * 'select()', so we disregard its contents.  Also, note that
		 * on some systems, tv_sec and tv_usec are unsigned.
		 */
		ntimeout.tv_sec  = whole_secs;
		ntimeout.tv_usec = micro_secs;

#define DELTA(f) (long)ntimeout.f - (long)returntime.f + (long)starttime.f

		delta = DELTA(tv_sec);
		if (delta < 0)
			delta = 0;
		ntimeout.tv_sec = delta;

		delta = DELTA(tv_usec);
		while (delta < 0 && ntimeout.tv_sec != 0) {
			ntimeout.tv_sec--;
			delta += 1000000;
		}
		ntimeout.tv_usec = delta;
		if (delta < 0)
			ntimeout.tv_sec = ntimeout.tv_usec = 0;

		/*
		 * 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
		 && (ntimeout.tv_sec != 0 || ntimeout.tv_usec > 100000)) {
			napms(100);
			goto retry;
		}
#endif
#ifdef HIDE_EINTR
	} while (result == -1 && errno == EINTR);
#endif

	/* return approximate time left on the ntimeout, in milliseconds */
	if (timeleft)
		*timeleft = (ntimeout.tv_sec * 1000) + (ntimeout.tv_usec / 1000);

	T(("end twait: returned %d (%d), remaining time %lu.%06lu secs (%d msec)",
		result, errno,
		(long) ntimeout.tv_sec, (long) ntimeout.tv_usec,
		timeleft ? *timeleft : -1));

	/*
	 * 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);
					count++;
				}
			}
#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);
}