/*
 * Copyright (c) 2015, Aleksey Demakov
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * * Redistributions of source code must retain the above copyright notice, this
 *   list of conditions and the following disclaimer.
 *
 * * Redistributions in binary form must reproduce the above copyright notice,
 *   this list of conditions and the following disclaimer in the documentation
 *   and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#include "pthread_barrier.h"

#include <errno.h>

#ifdef __APPLE__

#define __unused __attribute__((unused))

int pthread_barrierattr_init(pthread_barrierattr_t *attr __unused) { return 0; }

int pthread_barrierattr_destroy(pthread_barrierattr_t *attr __unused) {
  return 0;
}

int pthread_barrierattr_getpshared(
    const pthread_barrierattr_t *__restrict attr __unused,
    int *__restrict pshared) {
  *pshared = PTHREAD_PROCESS_PRIVATE;
  return 0;
}

int pthread_barrierattr_setpshared(pthread_barrierattr_t *attr __unused,
                                   int pshared) {
  if (pshared != PTHREAD_PROCESS_PRIVATE) {
    errno = EINVAL;
    return -1;
  }
  return 0;
}

int pthread_barrier_init(pthread_barrier_t *__restrict barrier,
                         const pthread_barrierattr_t *__restrict attr __unused,
                         unsigned count) {
  if (count == 0) {
    errno = EINVAL;
    return -1;
  }

  if (pthread_mutex_init(&barrier->mutex, 0) < 0) {
    return -1;
  }
  if (pthread_cond_init(&barrier->cond, 0) < 0) {
    int errno_save = errno;
    pthread_mutex_destroy(&barrier->mutex);
    errno = errno_save;
    return -1;
  }

  barrier->limit = count;
  barrier->count = 0;
  barrier->phase = 0;

  return 0;
}

int pthread_barrier_destroy(pthread_barrier_t *barrier) {
  pthread_mutex_destroy(&barrier->mutex);
  pthread_cond_destroy(&barrier->cond);
  return 0;
}

int pthread_barrier_wait(pthread_barrier_t *barrier) {
  pthread_mutex_lock(&barrier->mutex);
  barrier->count++;
  if (barrier->count >= barrier->limit) {
    barrier->phase++;
    barrier->count = 0;
    pthread_cond_broadcast(&barrier->cond);
    pthread_mutex_unlock(&barrier->mutex);
    return PTHREAD_BARRIER_SERIAL_THREAD;
  } else {
    unsigned phase = barrier->phase;
    do
      pthread_cond_wait(&barrier->cond, &barrier->mutex);
    while (phase == barrier->phase);
    pthread_mutex_unlock(&barrier->mutex);
    return 0;
  }
}

#endif /* __APPLE__ */