text: /* GNU Objective C Runtime Thread Interface
     Copyright (C) 1996, 1997 Free Software Foundation, Inc.
     Contributed by Galen C. Hunt (gchunt@cs.rochester.edu)
     Conditions added by Mircea Oancea (mircea@first.elcom.pub.ro)
        
  This file is part of GCC.
  
  GCC 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 2, or (at your option) any later version.
  
  GCC 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.
  
  You should have received a copy of the GNU General Public License along with
  GCC; see the file COPYING.  If not, write to the Free Software
  Foundation, 59 Temple Place - Suite 330,
  Boston, MA 02111-1307, USA.  */
  
  /* As a special exception, if you link this library with files compiled with
     GCC to produce an executable, this does not cause the resulting executable
     to be covered by the GNU General Public License. This exception does not
     however invalidate any other reasons why the executable file might be
     covered by the GNU General Public License.  */
  
  #include <objc/thr.h>
  #include "runtime.h"
  
  #include <thread.h>
  #include <synch.h>
  #include <errno.h>
  
  /* Key structure for maintaining thread specific storage */
  static thread_key_t     __objc_thread_data_key;
  
  /* Backend initialization functions */
  
  /* Initialize the threads subsystem. */
  int
  __objc_init_thread_system(void)
  {
    /* Initialize the thread storage key */
    if (thr_keycreate(&__objc_thread_data_key, NULL) == 0)
      return 0;
    else
      return -1;
  }
  
  /* Close the threads subsystem. */
  int
  __objc_close_thread_system(void)
  {
    return 0;
  }
  
  /* Backend thread functions */
  
  /* Create a new thread of execution. */
  objc_thread_t
  __objc_thread_detach(void (*func)(void *arg), void *arg)
  {
    objc_thread_t thread_id;
    thread_t new_thread_id = 0;
  
    if (thr_create(NULL, 0, (void *)func, arg,
                   THR_DETACHED | THR_NEW_LWP,
                   &new_thread_id) == 0)
      thread_id = *(objc_thread_t *)&new_thread_id;
    else
      thread_id = NULL;
    
    return thread_id;
  }
  
  /* Set the current thread's priority. */
  int
  __objc_thread_set_priority(int priority)
  {
    int sys_priority = 0;
  
    switch (priority)
      {
      case OBJC_THREAD_INTERACTIVE_PRIORITY:
        sys_priority = 300;
        break;
      default:
      case OBJC_THREAD_BACKGROUND_PRIORITY:
        sys_priority = 200;
        break;
      case OBJC_THREAD_LOW_PRIORITY:
        sys_priority = 1000;
        break;
      }
  
    /* Change priority */
    if (thr_setprio(thr_self(), sys_priority) == 0)
      return 0;
    else
      return -1;
  }
  
  /* Return the current thread's priority. */
  int
  __objc_thread_get_priority(void)
  {
    int sys_priority;
                                                     
    if (thr_getprio(thr_self(), &sys_priority) == 0)
      {
        if (sys_priority >= 250)
  	return OBJC_THREAD_INTERACTIVE_PRIORITY;
        else if (sys_priority >= 150)
  	return OBJC_THREAD_BACKGROUND_PRIORITY;
        return OBJC_THREAD_LOW_PRIORITY;
      }
  
    /* Couldn't get priority. */
    return -1;
  }
  
  /* Yield our process time to another thread. */
  void
  __objc_thread_yield(void)
  {
    thr_yield();
  }
  
  /* Terminate the current thread. */
  int
  __objc_thread_exit(void)
  {
    /* exit the thread */
    thr_exit(&__objc_thread_exit_status);
  
    /* Failed if we reached here */
    return -1;
  }
  
  /* Returns an integer value which uniquely describes a thread. */
  objc_thread_t
  __objc_thread_id(void)
  {
    return (objc_thread_t)thr_self();
  }
  
  /* Sets the thread's local storage pointer. */
  int
  __objc_thread_set_data(void *value)
  {
    if (thr_setspecific(__objc_thread_data_key, value) == 0)
      return 0;
    else
      return -1;
  }
  
  /* Returns the thread's local storage pointer. */
  void *
  __objc_thread_get_data(void)
  {
    void *value = NULL;
  
    if (thr_getspecific(__objc_thread_data_key, &value) == 0)
      return value;
  
    return NULL;
  }
  
  /* Backend mutex functions */
  
  /* Allocate a mutex. */
  int
  __objc_mutex_allocate(objc_mutex_t mutex)
  {
    if (mutex_init( (mutex_t *)(&(mutex->backend)), USYNC_THREAD, 0))
      return -1;
    else
      return 0;
  }
  
  
  /* Deallocate a mutex. */
  int
  __objc_mutex_deallocate(objc_mutex_t mutex)
  {
    mutex_destroy((mutex_t *)(&(mutex->backend)));
    return 0;
  }
  
  /* Grab a lock on a mutex. */
  int
  __objc_mutex_lock(objc_mutex_t mutex)
  {
    if (mutex_lock((mutex_t *)(&(mutex->backend))) != 0)
      return -1;
    else
      return 0;
  }
  
  /* Try to grab a lock on a mutex. */
  int
  __objc_mutex_trylock(objc_mutex_t mutex)
  {
    if (mutex_trylock((mutex_t *)(&(mutex->backend))) != 0)
      return -1;
    else
      return 0;
  }
  
  /* Unlock the mutex */
  int
  __objc_mutex_unlock(objc_mutex_t mutex)
  {
    if (mutex_unlock((mutex_t *)(&(mutex->backend))) != 0)
      return -1;
    else
      return 0;
  }
  
  /* Backend condition mutex functions */
  
  /* Allocate a condition. */
  int
  __objc_condition_allocate(objc_condition_t condition)
  {
    return cond_init((cond_t *)(&(condition->backend)), USYNC_THREAD, NULL);
  }
  
  /* Deallocate a condition. */
  int
  __objc_condition_deallocate(objc_condition_t condition)
  {
    return cond_destroy((cond_t *)(&(condition->backend)));
  }
  
  /* Wait on the condition */
  int
  __objc_condition_wait(objc_condition_t condition, objc_mutex_t mutex)
  {
    return cond_wait((cond_t *)(&(condition->backend)),
  		   (mutex_t *)(&(mutex->backend)));
  }
  
  /* Wake up all threads waiting on this condition. */
  int
  __objc_condition_broadcast(objc_condition_t condition)
  {
    return cond_broadcast((cond_t *)(&(condition->backend)));
  }
  
  /* Wake up one thread waiting on this condition. */
  int
  __objc_condition_signal(objc_condition_t condition)
  {
    return cond_signal((cond_t *)(&(condition->backend)));
  }
  
  /* End of File */
  