OpenShot Library | libopenshot-audio  0.1.9
juce_MidiOutput.cpp
1 /*
2  ==============================================================================
3 
4  This file is part of the JUCE library.
5  Copyright (c) 2017 - ROLI Ltd.
6 
7  JUCE is an open source library subject to commercial or open-source
8  licensing.
9 
10  The code included in this file is provided under the terms of the ISC license
11  http://www.isc.org/downloads/software-support-policy/isc-license. Permission
12  To use, copy, modify, and/or distribute this software for any purpose with or
13  without fee is hereby granted provided that the above copyright notice and
14  this permission notice appear in all copies.
15 
16  JUCE IS PROVIDED "AS IS" WITHOUT ANY WARRANTY, AND ALL WARRANTIES, WHETHER
17  EXPRESSED OR IMPLIED, INCLUDING MERCHANTABILITY AND FITNESS FOR PURPOSE, ARE
18  DISCLAIMED.
19 
20  ==============================================================================
21 */
22 
23 namespace juce
24 {
25 
27 {
28  PendingMessage (const void* data, int len, double timeStamp)
29  : message (data, len, timeStamp)
30  {}
31 
32  MidiMessage message;
33  PendingMessage* next;
34 };
35 
36 MidiOutput::MidiOutput (const String& deviceName)
37  : Thread ("midi out"), name (deviceName)
38 {
39 }
40 
42 {
43  MidiBuffer::Iterator i (buffer);
44  MidiMessage message;
45  int samplePosition; // Note: Not actually used, so no need to initialise.
46 
47  while (i.getNextEvent (message, samplePosition))
48  sendMessageNow (message);
49 }
50 
52  double millisecondCounterToStartAt,
53  double samplesPerSecondForBuffer)
54 {
55  // You've got to call startBackgroundThread() for this to actually work..
56  jassert (isThreadRunning());
57 
58  // this needs to be a value in the future - RTFM for this method!
59  jassert (millisecondCounterToStartAt > 0);
60 
61  auto timeScaleFactor = 1000.0 / samplesPerSecondForBuffer;
62 
63  const uint8* data;
64  int len, time;
65 
66  for (MidiBuffer::Iterator i (buffer); i.getNextEvent (data, len, time);)
67  {
68  auto eventTime = millisecondCounterToStartAt + timeScaleFactor * time;
69  auto* m = new PendingMessage (data, len, eventTime);
70 
71  const ScopedLock sl (lock);
72 
73  if (firstMessage == nullptr || firstMessage->message.getTimeStamp() > eventTime)
74  {
75  m->next = firstMessage;
76  firstMessage = m;
77  }
78  else
79  {
80  auto* mm = firstMessage;
81 
82  while (mm->next != nullptr && mm->next->message.getTimeStamp() <= eventTime)
83  mm = mm->next;
84 
85  m->next = mm->next;
86  mm->next = m;
87  }
88  }
89 
90  notify();
91 }
92 
94 {
95  const ScopedLock sl (lock);
96 
97  while (firstMessage != nullptr)
98  {
99  auto* m = firstMessage;
100  firstMessage = firstMessage->next;
101  delete m;
102  }
103 }
104 
106 {
107  startThread (9);
108 }
109 
111 {
112  stopThread (5000);
113 }
114 
115 void MidiOutput::run()
116 {
117  while (! threadShouldExit())
118  {
119  uint32 now = Time::getMillisecondCounter();
120  uint32 eventTime = 0;
121  uint32 timeToWait = 500;
122 
123  PendingMessage* message;
124 
125  {
126  const ScopedLock sl (lock);
127  message = firstMessage;
128 
129  if (message != nullptr)
130  {
131  eventTime = (uint32) roundToInt (message->message.getTimeStamp());
132 
133  if (eventTime > now + 20)
134  {
135  timeToWait = eventTime - (now + 20);
136  message = nullptr;
137  }
138  else
139  {
140  firstMessage = message->next;
141  }
142  }
143  }
144 
145  if (message != nullptr)
146  {
147  std::unique_ptr<PendingMessage> messageDeleter (message);
148 
149  if (eventTime > now)
150  {
152 
153  if (threadShouldExit())
154  break;
155  }
156 
157  if (eventTime > now - 200)
158  sendMessageNow (message->message);
159  }
160  else
161  {
162  jassert (timeToWait < 1000 * 30);
163  wait ((int) timeToWait);
164  }
165  }
166 
168 }
169 
170 } // namespace juce
static void waitForMillisecondCounter(uint32 targetTime) noexcept
Waits until the getMillisecondCounter() reaches a given value.
Definition: juce_Time.cpp:252
bool stopThread(int timeOutMilliseconds)
Attempts to stop the thread running.
Encapsulates a MIDI message.
bool getNextEvent(MidiMessage &result, int &samplePosition) noexcept
Retrieves a copy of the next event from the buffer.
Thread(const String &threadName, size_t threadStackSize=0)
Creates a thread.
Definition: juce_Thread.cpp:26
void notify() const
Wakes up the thread.
The JUCE String class!
Definition: juce_String.h:42
void sendBlockOfMessages(const MidiBuffer &buffer, double millisecondCounterToStartAt, double samplesPerSecondForBuffer)
This lets you supply a block of messages that will be sent out at some point in the future...
void stopBackgroundThread()
Stops the background thread, and clears any pending midi events.
void startBackgroundThread()
Starts up a background thread so that the device can send blocks of data.
void sendMessageNow(const MidiMessage &message)
Sends out a MIDI message immediately.
void clearAllPendingMessages()
Gets rid of any midi messages that had been added by sendBlockOfMessages().
bool threadShouldExit() const
Checks whether the thread has been told to stop running.
Holds a sequence of time-stamped midi events.
bool isThreadRunning() const
Returns true if the thread is currently active.
double getTimeStamp() const noexcept
Returns the timestamp associated with this message.
Used to iterate through the events in a MidiBuffer.
Automatically locks and unlocks a mutex object.
bool wait(int timeOutMilliseconds) const
Suspends the execution of this thread until either the specified timeout period has elapsed...
void startThread()
Starts the thread running.
static uint32 getMillisecondCounter() noexcept
Returns the number of millisecs since a fixed event (usually system startup).
Definition: juce_Time.cpp:226
void sendBlockOfMessagesNow(const MidiBuffer &buffer)
Sends out a sequence of MIDI messages immediately.