tvsleep.c   [plain text]

/***********************************************************************
*                                                                      *
*               This software is part of the ast package               *
*          Copyright (c) 1985-2007 AT&T Intellectual Property          *
*                      and is licensed under the                       *
*                  Common Public License, Version 1.0                  *
*                    by AT&T Intellectual Property                     *
*                                                                      *
*                A copy of the License is available at                 *
*            http://www.opensource.org/licenses/cpl1.0.txt             *
*         (with md5 checksum 059e8cd6165cb4c31e351f2b69388fd9)         *
*                                                                      *
*              Information and Software Systems Research               *
*                            AT&T Research                             *
*                           Florham Park NJ                            *
*                                                                      *
*                 Glenn Fowler <gsf@research.att.com>                  *
*                  David Korn <dgk@research.att.com>                   *
*                   Phong Vo <kpv@research.att.com>                    *
*                                                                      *
***********************************************************************/
#pragma prototyped

#include <tv.h>
#include <tm.h>

#include "FEATURE/tvlib"

#if !_lib_nanosleep
# if _lib_select
#  if _sys_select
#   include <sys/select.h>
#  else
#   include <sys/socket.h>
#  endif
# else
#  if !_lib_usleep
#   if _lib_poll_notimer
#    undef _lib_poll
#   endif
#   if _lib_poll
#    include <poll.h>
#   endif
#  endif
# endif
#endif

/*
 * sleep for tv
 * non-zero exit if sleep did not complete
 * with remaining time in rv
 */

int
tvsleep(register const Tv_t* tv, register Tv_t* rv)
{

#if _lib_nanosleep

	struct timespec	stv;
	struct timespec	srv;
	int		r;

	stv.tv_sec = tv->tv_sec;
	stv.tv_nsec = tv->tv_nsec;
	if ((r = nanosleep(&stv, &srv)) && rv)
	{
		rv->tv_sec = srv.tv_sec;
		rv->tv_nsec = srv.tv_nsec;
	}
	return r;

#else

#if _lib_select

	struct timeval	stv;

	stv.tv_sec = tv->tv_sec;
	stv.tv_usec = tv->tv_nsec / 1000;
	if (select(0, NiL, NiL, NiL, &stv) < 0)
	{
		if (rv)
			*rv = *tv;
		return -1;
	}
	if (rv)
	{
		rv->tv_sec = stv.tv_sec;
		rv->tv_nsec = stv.tv_usec * 1000;
	}
	return 0;

#else

	unsigned int		s = tv->tv_sec;
	uint32_t		n = tv->tv_nsec;

#if _lib_usleep


	unsigned long		t;

	if (t = (n + 999L) / 1000L)
	{
		usleep(t);
		s -= t / 1000000L;
		n = 0;
	}

#else

#if _lib_poll

	struct pollfd		pfd;
	int			t;

	if ((t = (n + 999999L) / 1000000L) > 0)
	{
		poll(&pfd, 0, t);
		s -= t / 1000L;
		n = 0;
	}

#endif

#endif

	if ((s += (n + 999999999L) / 1000000000L) && (s = sleep(s)))
	{
		if (rv)
		{
			rv->tv_sec = s;
			rv->tv_nsec = 0;
		}
		return -1;
	}
	return 0;

#endif

#endif

}