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LOCKS (code)

Lock::Lock(const char* debugName) {
  name = debugName;
  s = new Semaphore(name,1);
  locked = true;
  owner = NULL;
}

Lock::~Lock() {
  delete s;
  delete owner;
}

void Lock::Acquire() {
  s->P();
  locked = true;
  owner = currentThread;
}

bool Lock::isHeldByCurrentThread() {
  return(owner == currentThread);
}

void Lock::Release() {
  if(locked && isHeldByCurrentThread()) {
    locked = false;
    owner = NULL;
    s->V();
  }
}

CONDITIONAL VARIABLES (code)

Condition::Condition(const char* debugName, Lock* conditionLock) {
  name = debugName;
  l = conditionLock;
  queue = new List;
}

Condition::~Condition() {
  delete l;
  delete queue;
}

void Condition::Wait() {
  Semaphore *temp;
  
  if(l->isHeldByCurrentThread()) {
    temp = new Semaphore("condition", 0);
    queue->Append(temp);
    l->Release();
    temp->P();
    l->Acquire();
    delete temp;
  }
}

void Condition::Signal() {
  Semaphore *temp;
  
  if(l->isHeldByCurrentThread()) {
    if(!queue->IsEmpty()) {
      temp = queue->Remove();
      temp->V();
    }
  }
}

void Condition::Broadcast() {
  while(!queue->IsEmpty()) {
    Signal();
  }
}