jack2/common/JackMidiAsyncWaitQueue.cpp at develop · jackaudio/jack2 · GitHub

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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;

}

jack2/common/JackMidiAsyncWaitQueue.cpp at develop · jackaudio/jack2 · GitHub

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