Jack2: JackMidiAsyncWaitQueue.cpp Source File

Jack2 1.9.12

JackMidiAsyncWaitQueue.cpp
1 /*
2 Copyright (C) 2010 Devin Anderson
3
4 This program is free software; you can redistribute it and/or modify
5 it under the terms of the GNU Lesser General Public License as published by
6 the Free Software Foundation; either version 2.1 of the License, or
7 (at your option) any later version.
8
9 This program is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 GNU Lesser General Public License for more details.
13
14 You should have received a copy of the GNU Lesser General Public License
15 along with this program; if not, write to the Free Software
16 Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
17
18 */
19
20 #include <new>
21
22 #include "JackMidiAsyncWaitQueue.h"
23 #include "JackMidiUtil.h"
24 #include "JackTime.h"
25
26 using Jack::JackMidiAsyncWaitQueue;
27
28 JackMidiAsyncWaitQueue::JackMidiAsyncWaitQueue(size_t max_bytes,
29 size_t max_messages):
30 JackMidiAsyncQueue(max_bytes, max_messages)
31 {
32 if (semaphore.Allocate("JackMidiAsyncWaitQueue", "midi-thread", 0)) {
33 throw std::bad_alloc();
34 }
35 }
36
37 JackMidiAsyncWaitQueue::~JackMidiAsyncWaitQueue()
38 {
39 semaphore.Destroy();
40 }
41
42 jack_midi_event_t *
43 JackMidiAsyncWaitQueue::DequeueEvent()
44 {
45 return DequeueEvent((long) 0);
46 }
47
48 jack_midi_event_t *
49 JackMidiAsyncWaitQueue::DequeueEvent(jack_nframes_t frame)
50 {
51
52 // XXX: I worry about timer resolution on Solaris and Windows. When the
53 // resolution for the `JackSynchro` object is milliseconds, the worst-case
54 // scenario for processor objects is that the wait time becomes less than a
55 // millisecond, and the processor object continually calls this method,
56 // expecting to wait a certain amount of microseconds, and ends up not
57 // waiting at all each time, essentially busy-waiting until the current
58 // frame is reached. Perhaps there should be a #define that indicates the
59 // wait time resolution for `JackSynchro` objects so that we can wait a
60 // little longer if necessary.
61
62 jack_time_t frame_time = GetTimeFromFrames(frame);
63 jack_time_t current_time = GetMicroSeconds();
64 return DequeueEvent((frame_time < current_time) ? 0 :
65 (long) (frame_time - current_time));
66 }
67
68 jack_midi_event_t *
69 JackMidiAsyncWaitQueue::DequeueEvent(long usec)
70 {
71 return ((usec < 0) ? semaphore.Wait() : semaphore.TimedWait(usec)) ?
72 JackMidiAsyncQueue::DequeueEvent() : 0;
73 }
74
75 Jack::JackMidiWriteQueue::EnqueueResult
76 JackMidiAsyncWaitQueue::EnqueueEvent(jack_nframes_t time, size_t size,
77 jack_midi_data_t *buffer)
78 {
79 EnqueueResult result = JackMidiAsyncQueue::EnqueueEvent(time, size,
80 buffer);
81 if (result == OK) {
82 semaphore.Signal();
83 }
84 return result;
85 }
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