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/*
Copyright (C) 2010 Devin Anderson
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 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 Lesser General Public License for more details.
You should have received a copy of the GNU Lesser 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 __JackMidiAsyncQueue__
#define __JackMidiAsyncQueue__
#include "JackMidiPort.h"
#include "JackMidiReadQueue.h"
#include "JackMidiWriteQueue.h"
#include "ringbuffer.h"
namespace Jack {
/**
* This is a MIDI message queue designed to allow one thread to pass MIDI
* messages to another thread (though it can also be used to buffer events
* internally). This is especially useful if the MIDI API you're
* attempting to interface with doesn't provide the ability to schedule
* MIDI events ahead of time and/or has blocking send/receive calls, as it
* allows a separate thread to handle input/output while the JACK process
* thread copies events from a MIDI buffer to this queue, or vice versa.
*/
class SERVER_EXPORT JackMidiAsyncQueue:
public JackMidiReadQueue, public JackMidiWriteQueue {
private:
static const size_t INFO_SIZE =
sizeof(jack_nframes_t) + sizeof(size_t);
jack_ringbuffer_t *byte_ring;
jack_midi_data_t *data_buffer;
jack_midi_event_t dequeue_event;
jack_ringbuffer_t *info_ring;
size_t max_bytes;
public:
using JackMidiWriteQueue::EnqueueEvent;
/**
* Creates a new asynchronous MIDI message queue. The queue can store
* up to `max_messages` MIDI messages and up to `max_bytes` of MIDI
* data before it starts rejecting messages.
*/
JackMidiAsyncQueue(size_t max_bytes=4096, size_t max_messages=1024);
virtual
~JackMidiAsyncQueue();
/**
* Dequeues and returns a MIDI event. Returns '0' if there are no MIDI
* events available. This method may be overridden.
*/
virtual jack_midi_event_t *
DequeueEvent();
/**
* Enqueues the MIDI event specified by the arguments. The return
* value indicates whether or not the event was successfully enqueued.
* This method may be overridden.
*/
virtual EnqueueResult
EnqueueEvent(jack_nframes_t time, size_t size,
jack_midi_data_t *buffer);
/**
* Returns the maximum size event that can be enqueued right *now*.
*/
size_t
GetAvailableSpace();
};
}
#endif
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