bug 225:

Thread-safe queue.

Appl/CEP/CS1/CS1_Interface/include/CS1_Interface/Queue.h

+//# Queue.h:
+//#
+//#  Copyright (C) 2007
+//#  ASTRON (Netherlands Foundation for Research in Astronomy)
+//#  P.O.Box 2, 7990 AA Dwingeloo, The Netherlands, seg@astron.nl
+//#
+//#  This program 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 of the License, or
+//#  (at your option) any later version.
+//#
+//#  This program 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 this program; if not, write to the Free Software
+//#  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+//#
+//#  $Id$
+
+#ifndef LOFAR_CS1_INTERFACE_QUEUE_H
+#define LOFAR_CS1_INTERFACE_QUEUE_H
+
+#include <pthread.h>
+#include <list>
+
+
+namespace LOFAR {
+namespace CS1 {
+
+template <typename T> class Queue
+{
+  public:
+	 Queue();
+	 ~Queue();
+
+    void append(T);
+    T    remove();
+
+  private:
+    pthread_mutex_t mutex;
+    pthread_cond_t  newElementAppended;
+    std::list<T>    queue;
+};
+
+
+template <typename T> inline Queue<T>::Queue()
+{
+  pthread_mutex_init(&mutex, 0);
+  pthread_cond_init(&newElementAppended, 0);
+}
+
+
+template <typename T> inline Queue<T>::~Queue()
+{
+  pthread_mutex_destroy(&mutex);
+  pthread_cond_destroy(&newElementAppended);
+}
+
+
+template <typename T> inline void Queue<T>::append(T element)
+{
+  pthread_mutex_lock(&mutex);
+  queue.push_back(element);
+  pthread_cond_signal(&newElementAppended);
+  pthread_mutex_unlock(&mutex);
+}
+
+
+template <typename T> inline T Queue<T>::remove()
+{
+  pthread_mutex_lock(&mutex);
+
+  while (queue.empty())
+    pthread_cond_wait(&newElementAppended, &mutex);
+
+  T element = queue.front();
+  queue.pop_front();
+  pthread_mutex_unlock(&mutex);
+
+  return element;
+}
+
+} // namespace CS1
+} // namespace LOFAR
+
+#endif