84 lines
2.5 KiB
C++
84 lines
2.5 KiB
C++
/* This file is part of Om. Copyright (C) 2006 Dave Robillard.
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*
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* Om is free software; you can redistribute it and/or modify it under the
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* terms of the GNU General Public License as published by the Free Software
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* Foundation; either version 2 of the License, or (at your option) any later
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* version.
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*
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* Om is distributed in the hope that it will be useful, but WITHOUT ANY
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* WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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* FOR A PARTICULAR PURPOSE. See the GNU General Public License for details.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program; if not, write to the Free Software Foundation, Inc.,
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* 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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#ifndef QUEUEDEVENTSOURCE_H
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#define QUEUEDEVENTSOURCE_H
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#include <cstdlib>
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#include <pthread.h>
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#include "util/types.h"
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#include "util/Semaphore.h"
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#include "EventSource.h"
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namespace Om {
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class Event;
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class QueuedEvent;
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/** Queue of events that need processing before reaching the audio thread.
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*
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* Implemented as a deque (ringbuffer) in a circular array. Pushing and
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* popping are threadsafe, as long as a single thread pushes and a single
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* thread pops (ie this data structure is threadsafe, but the push and pop
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* methods themselves are not).
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*/
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class QueuedEventSource : public EventSource
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{
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public:
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QueuedEventSource(size_t size);
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~QueuedEventSource();
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Event* pop_earliest_event_before(const samplecount time);
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void unblock();
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void start();
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void stop();
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protected:
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void push(QueuedEvent* const ev);
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private:
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// Prevent copies (undefined)
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QueuedEventSource(const QueuedEventSource&);
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QueuedEventSource& operator=(const QueuedEventSource&);
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// Note that it's crucially important which functions access which of these
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// variables, to maintain threadsafeness.
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size_t m_front; ///< Front of queue
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size_t m_back; ///< Back of entire queue (1 past index of back element)
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size_t m_prepared_back; ///< Back of prepared section (1 past index of back prepared element)
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const size_t m_size;
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QueuedEvent** m_events;
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bool m_thread_exists;
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bool m_prepare_thread_exit_flag;
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pthread_t m_prepare_thread;
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Semaphore m_semaphore; ///< Counting semaphor for driving prepare thread
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pthread_mutex_t m_blocking_mutex;
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pthread_cond_t m_blocking_cond;
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static void* prepare_loop(void* q) { return ((QueuedEventSource*)q)->m_prepare_loop(); }
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void* m_prepare_loop();
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};
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} // namespace Om
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#endif // QUEUEDEVENTSOURCE_H
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