1 files changed, 83 insertions, 0 deletions
diff --git a/src/engine/QueuedEventSource.h b/src/engine/QueuedEventSource.h
new file mode 100644
index 00000000..002fc642
--- /dev/null
+++ b/src/engine/QueuedEventSource.h
@@ -0,0 +1,83 @@
+/* This file is part of Om.  Copyright (C) 2006 Dave Robillard.
+ * 
+ * Om 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.
+ * 
+ * Om 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 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
+ */
+
+#ifndef QUEUEDEVENTSOURCE_H
+#define QUEUEDEVENTSOURCE_H
+
+#include <cstdlib>
+#include <pthread.h>
+#include "util/types.h"
+#include "util/Semaphore.h"
+#include "EventSource.h"
+
+namespace Om {
+
+class Event;
+class QueuedEvent;
+
+
+/** Queue of events that need processing before reaching the audio thread.
+ *
+ * Implemented as a deque (ringbuffer) in a circular array.  Pushing and
+ * popping are threadsafe, as long as a single thread pushes and a single
+ * thread pops (ie this data structure is threadsafe, but the push and pop
+ * methods themselves are not).
+ */
+class QueuedEventSource : public EventSource
+{
+public:
+	QueuedEventSource(size_t size);
+	~QueuedEventSource();
+
+	Event* pop_earliest_event_before(const samplecount time);
+
+	void unblock();
+
+	void start();
+	void stop();
+
+protected:
+	void push(QueuedEvent* const ev);
+
+private:
+	// Prevent copies (undefined)
+	QueuedEventSource(const QueuedEventSource&);
+	QueuedEventSource& operator=(const QueuedEventSource&);
+	
+	// Note that it's crucially important which functions access which of these
+	// variables, to maintain threadsafeness.
+	
+	size_t      m_front;         ///< Front of queue
+	size_t      m_back;          ///< Back of entire queue (1 past index of back element)
+	size_t      m_prepared_back; ///< Back of prepared section (1 past index of back prepared element)
+	const size_t m_size;
+	QueuedEvent**  m_events;
+	
+	bool            m_thread_exists;
+	bool            m_prepare_thread_exit_flag;
+	pthread_t       m_prepare_thread;
+	Semaphore       m_semaphore; ///< Counting semaphor for driving prepare thread
+	pthread_mutex_t m_blocking_mutex;
+	pthread_cond_t  m_blocking_cond;
+
+	static void* prepare_loop(void* q) { return ((QueuedEventSource*)q)->m_prepare_loop(); }
+	void* m_prepare_loop();
+};
+
+
+} // namespace Om
+
+#endif // QUEUEDEVENTSOURCE_H