/* clock_gettime -- Get the current time from a POSIX clockid_t.  Unix version.

   Copyright (C) 1999-2018 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 <errno.h>

#include <stdint.h>

#include <time.h>

#include <sys/time.h>

#include <libc-internal.h>

#include <ldsodefs.h>

#if HP_TIMING_AVAIL

/* Clock frequency of the processor.  We make it a 64-bit variable

   because some jokers are already playing with processors with more

   than 4GHz.  */

static hp_timing_t freq;

/* This function is defined in the thread library.  */

extern int __pthread_clock_gettime (clockid_t clock_id, hp_timing_t freq,

				    struct timespec *tp)

     __attribute__ ((__weak__));

static int

hp_timing_gettime (clockid_t clock_id, struct timespec *tp)

{

  hp_timing_t tsc;

  if (__glibc_unlikely (freq == 0))

    {

      /* This can only happen if we haven't initialized the `freq'

	 variable yet.  Do this now. We don't have to protect this

	 code against multiple execution since all of them should

	 lead to the same result.  */

      freq = __get_clockfreq ();

      if (__glibc_unlikely (freq == 0))

	/* Something went wrong.  */

	return -1;

    }

  if (clock_id != CLOCK_PROCESS_CPUTIME_ID

      && __pthread_clock_gettime != NULL)

    return __pthread_clock_gettime (clock_id, freq, tp);

  /* Get the current counter.  */

  HP_TIMING_NOW (tsc);

  /* Compute the offset since the start time of the process.  */

  tsc -= GL(dl_cpuclock_offset);

  /* Compute the seconds.  */

  tp->tv_sec = tsc / freq;

  /* And the nanoseconds.  This computation should be stable until

     we get machines with about 16GHz frequency.  */

  tp->tv_nsec = ((tsc % freq) * UINT64_C (1000000000)) / freq;

  return 0;

}

#endif

static inline int

realtime_gettime (struct timespec *tp)

{

  struct timeval tv;

  int retval = __gettimeofday (&tv, NULL);

  if (retval == 0)

    /* Convert into `timespec'.  */

    TIMEVAL_TO_TIMESPEC (&tv, tp);

  return retval;

}

/* Get current value of CLOCK and store it in TP.  */

int

__clock_gettime (clockid_t clock_id, struct timespec *tp)

{

  int retval = -1;

  switch (clock_id)

    {

#ifdef SYSDEP_GETTIME

      SYSDEP_GETTIME;

#endif

#ifndef HANDLED_REALTIME

    case CLOCK_REALTIME:

      {

	struct timeval tv;

	retval = __gettimeofday (&tv, NULL);

	if (retval == 0)

	  TIMEVAL_TO_TIMESPEC (&tv, tp);

      }

      break;

#endif

    default:

#ifdef SYSDEP_GETTIME_CPU

      SYSDEP_GETTIME_CPU (clock_id, tp);

#endif

#if HP_TIMING_AVAIL

      if ((clock_id & ((1 << CLOCK_IDFIELD_SIZE) - 1))

	  == CLOCK_THREAD_CPUTIME_ID)

	retval = hp_timing_gettime (clock_id, tp);

      else

#endif

	__set_errno (EINVAL);

      break;

#if HP_TIMING_AVAIL && !defined HANDLED_CPUTIME

    case CLOCK_PROCESS_CPUTIME_ID:

      retval = hp_timing_gettime (clock_id, tp);

      break;

#endif

    }

  return retval;

}

weak_alias (__clock_gettime, clock_gettime)

libc_hidden_def (__clock_gettime)