SynchronizedQueue: optional upper bound

git-svn-id: https://www4.informatik.uni-erlangen.de/i4svn/danceos/trunk/devel/fail@1944 8c4709b5-6ec9-48aa-a5cd-a96041d1645a

src/core/util/SynchronizedQueue.hpp

@@ -17,11 +17,15 @@ template <typename T>
 class SynchronizedQueue { // Adapted from: http://www.quantnet.com/cplusplus-multithreading-boost/
 private:
 	std::queue<T> m_queue; //!< Use STL queue to store data
+	unsigned capacity;
 #ifndef __puma
 	boost::mutex m_mutex; //!< The mutex to synchronise on
 	boost::condition_variable m_cond; //!< The condition to wait for
+	boost::condition_variable m_cond_capacity; //!< Another condition to wait for
 #endif
 public:
+	SynchronizedQueue() : capacity(0) {}
+	SynchronizedQueue(unsigned capacity) : capacity(capacity) {}
 	int Size()
 	{
 #ifndef __puma
@@ -36,6 +40,13 @@ public:
 #ifndef __puma
 		boost::unique_lock<boost::mutex> lock(m_mutex);
 #endif
+
+		while (capacity != 0 && m_queue.size() >= capacity) {
+#ifndef __puma
+			m_cond_capacity.wait(lock);
+#endif
+		}
+
 			// Add the data to the queue
 		m_queue.push(data);
 			// Notify others that data is ready
@@ -62,6 +73,13 @@ public:
 #endif
 		// Retrieve the data from the queue
 		T result=m_queue.front(); m_queue.pop();
+
+		// Notify others that we have free slots
+#ifndef __puma
+		if (m_queue.size() < capacity) {
+			m_cond_capacity.notify_one();
+		}
+#endif
 		return result;
 	} // Lock is automatically released here
 
@@ -84,7 +102,13 @@ public:
 		if (m_queue.size() > 0) {
 			// Retrieve the data from the queue
 			d = m_queue.front(); m_queue.pop();
-		return true;
+			// Notify others that we have free slots
+#ifndef __puma
+			if (m_queue.size() < capacity) {
+				m_cond_capacity.notify_one();
+			}
+#endif
+			return true;
 		} else {
 			return false;
 		}