sclass FastCollab is ICollab {
  settable bool useMainThread = true;
  volatile settable bool done;
  int coresToUse;
  FastCollabWorker[] workers;
  AtomicReferenceArray<Runnable> workArray;
  
  *(int coresToUse) {
    this.coresToUse = max(1, coresToUse);
    workArray = new AtomicReferenceArray(this.coresToUse);
  }
  
  public void addWork(Runnable work) {
    if (work == null) ret;
    for (int i = 0; i < workArray.length(); i++)
      if (workArray.compareAndSet(i, null, work))
        ret;
        
    // Everyone is busy - do the work ourselves
    work.run();
  }
  
  // returns null => sleep
  // returns done => all work done
  public Runnable grabWork(int workerIndex) {
    if (done) ret DONE;
    Runnable work = workArray.get(workerIndex);
    if (work != null)
      workArray.set(workerIndex, null);
    ret work;
  }
  
  toString { ret "FastCollab*" + n2(coresToUse); }
  
  run {
    workers = new FastCollabWorker[coresToUse];
    for i to coresToUse: 
      workers[i] = new FastCollabWorker(this, i);
      
    for (int i = useMainThread ? 1 : 0; i < coresToUse; i++)
      startThread(workers[i]);
    if (useMainThread)
      workers[0].run();
  }
}