/* Copyright (C) 2001-2018 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; see the file COPYING.LIB.  If

   not, see <http://www.gnu.org/licenses/>.  */

#include <errno.h>

#include <stdlib.h>

#include <time.h>

#include "pthreadP.h"

#if HP_TIMING_AVAIL

int

__pthread_clock_gettime (clockid_t clock_id, hp_timing_t freq,

			 struct timespec *tp)

{

  hp_timing_t tsc;

  /* Get the current counter.  */

  HP_TIMING_NOW (tsc);

  /* This is the ID of the thread we are looking for.  */

  pid_t tid = ((unsigned int) clock_id) >> CLOCK_IDFIELD_SIZE;

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

  if (tid == 0 || tid == THREAD_GETMEM (THREAD_SELF, tid))

    /* Our own clock.  */

    tsc -= THREAD_GETMEM (THREAD_SELF, cpuclock_offset);

  else

    {

      /* This is more complicated.  We have to locate the thread based

	 on the ID.  This means walking the list of existing

	 threads.  */

      struct pthread *thread = __find_thread_by_id (tid);

      if (thread == NULL)

	{

	  __set_errno (EINVAL);

	  return -1;

	}

      /* There is a race here.  The thread might terminate and the stack

	 become unusable.  But this is the user's problem.  */

      tsc -= thread->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) * 1000000000ull) / freq;

  return 0;

}

#endif