/*
 * mutex.c
 *
 * Description:
 * This translation unit implements mutual exclusion (mutex) primitives.
 */

#include "pthread.h"

static int
insert_attr(pthread_mutexattr_t *attr)
{
  /* Add this attribute object to a list. */

  /* FIXME: implement using some dynamic scheme. */
  return 0;
}

static int
is_attr(pthread_mutexattr_t *attr)
{
  /* Return 0 if present, 1 otherwise. */

  /* FIXME: implement. For now, pretend the attribute is always okay, unless
     it is NULL. */

  return (attr == NULL) ? 1 : 0;
}

static int
remove_attr(pthread_mutexattr_t *attr)
{
  /* Remove this attribute object from the list. */

  /* FIXME: implement. */
  return 0;
}

int
pthread_mutexattr_init(pthread_mutexattr_t *attr)
{
  if (attr == NULL)
    {
      /* This is disallowed. */
      return EINVAL;
    }

  attr->ptr = malloc(sizeof(_pthread_mutexattr_t));
  if (attr->ptr == NULL)
    {
      return ENOMEM;
    }
  
  (_pthread_mutexattr_t *) (attr->ptr).proc_shared = PTHREAD_PROCESS_PRIVATE;
  
  return 0;
}

int
pthread_mutexattr_destroy(pthread_mutexattr_t *attr)
{
  if (is_attr(attr) != 0)
    {
      return EINVAL;
    }
  else
    {
      free(attr->ptr);
      return 0;
    }
}

int
pthread_mutexattr_setpshared(pthread_mutexattr_t *attr, int process_shared)
{
  /* Ensure the value for this attribute is within the legal range. */
  if ((process_shared != PTHREAD_PROCESS_PRIVATE) ||
      (process_shared != PTHREAD_PROCESS_SHARED))
    {
      return EINVAL;
    }

  /* Ensure attr points to a valid attribute object. */
  if (is_attr(attr) != 0)
    {
      return EINVAL;
    }

  /* Everything is okay. */
  (_pthread_mutexattr_t *) (attr->ptr)->proc_shared = process_shared;
  return 0;
}

int
pthread_mutexattr_getpshared(const pthread_mutexattr_t *attr,
			     int *process_shared)
{
  if (is_attr(attr) != 0)
    {
      return EINVAL;
    }

  /* Everything is okay. */
  *process_shared = (_pthread_mutexattr_t *) (attr->ptr)->proc_shared;
  return 0;
}
  
int
pthread_mutexattr_setprotocol(pthread_mutexattr_t *attr,
			      int protocol)
{
  /* This function is not supported. */
  return ENOSYS;
}

int
pthread_mutexattr_getprotocol(const pthread_mutexattr_t *attr,
			     int *protocol)
{
  /* This function is not supported. */
  return ENOSYS;
}

int
pthread_mutexattr_setprioceiling(pthread_mutexattr_t *attr,
				 int ceiling)
{
  /* This function is not supported. */
  return ENOSYS;
}

int
pthread_mutexattr_getprioceiling(const pthread_mutexattr_t *attr,
				 int *ceiling)
{
  /* This function is not supported. */
  return ENOSYS;
}