JackMidiAsyncWaitQueue.cpp
/*
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.
*/
#include <new>
#include "JackMidiAsyncWaitQueue.h"
#include "JackMidiUtil.h"
#include "JackTime.h"
using Jack::JackMidiAsyncWaitQueue;
JackMidiAsyncWaitQueue::JackMidiAsyncWaitQueue(size_t max_bytes,
size_t max_messages):
JackMidiAsyncQueue(max_bytes, max_messages)
{
if (semaphore.Allocate("JackMidiAsyncWaitQueue", "midi-thread", 0)) {
throw std::bad_alloc();
}
}
JackMidiAsyncWaitQueue::~JackMidiAsyncWaitQueue()
{
semaphore.Destroy();
}
jack_midi_event_t *
JackMidiAsyncWaitQueue::DequeueEvent()
{
return DequeueEvent((long) 0);
}
jack_midi_event_t *
JackMidiAsyncWaitQueue::DequeueEvent(jack_nframes_t frame)
{
// XXX: I worry about timer resolution on Solaris and Windows. When the
// resolution for the `JackSynchro` object is milliseconds, the worst-case
// scenario for processor objects is that the wait time becomes less than a
// millisecond, and the processor object continually calls this method,
// expecting to wait a certain amount of microseconds, and ends up not
// waiting at all each time, essentially busy-waiting until the current
// frame is reached. Perhaps there should be a #define that indicates the
// wait time resolution for `JackSynchro` objects so that we can wait a
// little longer if necessary.
jack_time_t frame_time = GetTimeFromFrames(frame);
jack_time_t current_time = GetMicroSeconds();
return DequeueEvent((frame_time < current_time) ? 0 :
(long) (frame_time - current_time));
}
jack_midi_event_t *
JackMidiAsyncWaitQueue::DequeueEvent(long usec)
{
return ((usec < 0) ? semaphore.Wait() : semaphore.TimedWait(usec)) ?
JackMidiAsyncQueue::DequeueEvent() : 0;
}
Jack::JackMidiWriteQueue::EnqueueResult
JackMidiAsyncWaitQueue::EnqueueEvent(jack_nframes_t time, size_t size,
jack_midi_data_t *buffer)
{
EnqueueResult result = JackMidiAsyncQueue::EnqueueEvent(time, size,
buffer);
if (result == OK) {
semaphore.Signal();
}
return result;
}
Jack::JackMidiAsyncWaitQueue::EnqueueEvent
EnqueueResult EnqueueEvent(jack_nframes_t time, size_t size, jack_midi_data_t *buffer)
Definition: JackMidiAsyncWaitQueue.cpp:76
Jack::JackMidiAsyncQueue
Definition: JackMidiAsyncQueue.h:40
jack_midi_event_t
Definition: JackMidiPort.h:33
Jack::JackMidiAsyncWaitQueue::DequeueEvent
jack_midi_event_t * DequeueEvent()
Definition: JackMidiAsyncWaitQueue.cpp:43
Jack::JackMidiAsyncQueue::DequeueEvent
virtual jack_midi_event_t * DequeueEvent()
Definition: JackMidiAsyncQueue.cpp:53
Jack::JackMidiAsyncWaitQueue
Definition: JackMidiAsyncWaitQueue.h:39
Jack::JackMidiAsyncQueue::EnqueueEvent
virtual EnqueueResult EnqueueEvent(jack_nframes_t time, size_t size, jack_midi_data_t *buffer)
Definition: JackMidiAsyncQueue.cpp:72