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/* Copyright (C) 2005, 2006, 2009 Free Software Foundation, Inc.

   Contributed by Richard Henderson <rth@redhat.com>.

   This file is part of the GNU OpenMP Library (libgomp).

   Libgomp is free software; you can redistribute it and/or modify it

   under the terms of the GNU General Public License as published by

   the Free Software Foundation; either version 3, or (at your option)

   any later version.

   Libgomp 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 General Public License for

   more details.

   Under Section 7 of GPL version 3, you are granted additional

   permissions described in the GCC Runtime Library Exception, version

   3.1, as published by the Free Software Foundation.

   You should have received a copy of the GNU General Public License and

   a copy of the GCC Runtime Library Exception along with this program;

   see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see

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

/* This is the default POSIX 1003.1b implementation of a semaphore

   synchronization mechanism for libgomp.  This type is private to

   the library.

   This is a bit heavy weight for what we need, in that we're not

   interested in sem_wait as a cancelation point, but it's not too

   bad for a default.  */

#include "libgomp.h"

#ifdef HAVE_BROKEN_POSIX_SEMAPHORES

#include <stdlib.h>

void gomp_sem_init (gomp_sem_t *sem, int value)

{

  int ret;

  ret = pthread_mutex_init (&sem->mutex, NULL);

  if (ret)

    return;

  ret = pthread_cond_init (&sem->cond, NULL);

  if (ret)

    return;

  sem->value = value;

}

void gomp_sem_wait (gomp_sem_t *sem)

{

  int ret;

  ret = pthread_mutex_lock (&sem->mutex);

  if (ret)

    return;

  if (sem->value > 0)

    {

      sem->value--;

      ret = pthread_mutex_unlock (&sem->mutex);

      return;

    }

  while (sem->value <= 0)

    {

      ret = pthread_cond_wait (&sem->cond, &sem->mutex);

      if (ret)

        {

          pthread_mutex_unlock (&sem->mutex);

          return;

        }

    }

  sem->value--;

  ret = pthread_mutex_unlock (&sem->mutex);

  return;

}

void gomp_sem_post (gomp_sem_t *sem)

{

  int ret;

  ret = pthread_mutex_lock (&sem->mutex);

  if (ret)

    return;

  sem->value++;

  ret = pthread_mutex_unlock (&sem->mutex);

  if (ret)

    return;

  ret = pthread_cond_signal (&sem->cond);

  return;

}

void gomp_sem_destroy (gomp_sem_t *sem)

{

  int ret;

  ret = pthread_mutex_destroy (&sem->mutex);

  if (ret)

    return;

  ret = pthread_cond_destroy (&sem->cond);

  return;

}

#else /* HAVE_BROKEN_POSIX_SEMAPHORES  */

void

gomp_sem_wait (gomp_sem_t *sem)

{

  /* With POSIX, the wait can be canceled by signals.  We don't want that.

     It is expected that the return value here is -1 and errno is EINTR.  */

  while (sem_wait (sem) != 0)

    continue;

}

#endif