/* High-resolution sleep with the specified clock.

   Copyright (C) 2000-2018 Free Software Foundation, Inc.

   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or

   modify it under the terms of the GNU Lesser General Public

   License as published by the Free Software Foundation; either

   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,

   but WITHOUT ANY WARRANTY; without even the implied warranty of

   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public

   License along with the GNU C Library; if not, see

   <http://www.gnu.org/licenses/>.  */

#include <assert.h>

#include <errno.h>

#include <time.h>

#include <hp-timing.h>

#include <sysdep-cancel.h>

#if HP_TIMING_AVAIL

# define CPUCLOCK_P(clock) \

  ((clock) == CLOCK_PROCESS_CPUTIME_ID					      \

   || ((clock) & ((1 << CLOCK_IDFIELD_SIZE) - 1)) == CLOCK_THREAD_CPUTIME_ID)

#else

# define CPUCLOCK_P(clock) 0

#endif

#ifndef INVALID_CLOCK_P

# define INVALID_CLOCK_P(cl) \

  ((cl) < CLOCK_REALTIME || (cl) > CLOCK_THREAD_CPUTIME_ID)

#endif

/* This implementation assumes that these is only a `nanosleep' system

   call.  So we have to remap all other activities.  */

int

__clock_nanosleep (clockid_t clock_id, int flags, const struct timespec *req,

		   struct timespec *rem)

{

  struct timespec now;

  if (__builtin_expect (req->tv_nsec, 0) < 0

      || __builtin_expect (req->tv_nsec, 0) >= 1000000000)

    return EINVAL;

  if (clock_id == CLOCK_THREAD_CPUTIME_ID)

    return EINVAL;		/* POSIX specifies EINVAL for this case.  */

#ifdef SYSDEP_NANOSLEEP

  SYSDEP_NANOSLEEP;

#endif

  if (CPUCLOCK_P (clock_id))

    return ENOTSUP;

  if (INVALID_CLOCK_P (clock_id))

    return EINVAL;

  /* If we got an absolute time, remap it.  */

  if (flags == TIMER_ABSTIME)

    {

      long int nsec;

      long int sec;

      /* Make sure we use safe data types.  */

      assert (sizeof (sec) >= sizeof (now.tv_sec));

      /* Get the current time for this clock.  */

      if (__builtin_expect (__clock_gettime (clock_id, &now), 0) != 0)

	return errno;

      /* Compute the difference.  */

      nsec = req->tv_nsec - now.tv_nsec;

      sec = req->tv_sec - now.tv_sec - (nsec < 0);

      if (sec < 0)

	/* The time has already elapsed.  */

	return 0;

      now.tv_sec = sec;

      now.tv_nsec = nsec + (nsec < 0 ? 1000000000 : 0);

      /* From now on this is our time.  */

      req = &now;

      /* Make sure we are not modifying the struct pointed to by REM.  */

      rem = NULL;

    }

  else if (__builtin_expect (flags, 0) != 0)

    return EINVAL;

  else if (clock_id != CLOCK_REALTIME)

    /* Not supported.  */

    return ENOTSUP;

  return __builtin_expect (__nanosleep (req, rem), 0) ? errno : 0;

}

weak_alias (__clock_nanosleep, clock_nanosleep)