juce/source/src/audio/midi/juce_MidiOutput.cpp

   1 /*
   2   ==============================================================================
   3
   4    This file is part of the JUCE library - "Jules' Utility Class Extensions"
   5    Copyright 2004-11 by Raw Material Software Ltd.
   6
   7   ------------------------------------------------------------------------------
   8
   9    JUCE can be redistributed and/or modified under the terms of the GNU General
  10    Public License (Version 2), as published by the Free Software Foundation.
  11    A copy of the license is included in the JUCE distribution, or can be found
  12    online at www.gnu.org/licenses.
  13
  14    JUCE is distributed in the hope that it will be useful, but WITHOUT ANY
  15    WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
  16    A PARTICULAR PURPOSE.  See the GNU General Public License for more details.
  17
  18   ------------------------------------------------------------------------------
  19
  20    To release a closed-source product which uses JUCE, commercial licenses are
  21    available: visit www.rawmaterialsoftware.com/juce for more information.
  22
  23   ==============================================================================
  24 */
  25
  26 #include "../../core/juce_StandardHeader.h"
  27
  28 BEGIN_JUCE_NAMESPACE
  29
  30 #include "juce_MidiOutput.h"
  31 #include "../../core/juce_Time.h"
  32
  33
  34 //==============================================================================
  35 struct MidiOutput::PendingMessage
  36 {
  37     PendingMessage (const void* const data, const int len, const double timeStamp)
  38         : message (data, len, timeStamp)
  39     {}
  40
  41     MidiMessage message;
  42     PendingMessage* next;
  43 };
  44
  45 MidiOutput::MidiOutput()
  46     : Thread ("midi out"),
  47       internal (nullptr),
  48       firstMessage (nullptr)
  49 {
  50 }
  51
  52 void MidiOutput::sendBlockOfMessages (const MidiBuffer& buffer,
  53                                       const double millisecondCounterToStartAt,
  54                                       double samplesPerSecondForBuffer)
  55 {
  56     // You've got to call startBackgroundThread() for this to actually work..
  57     jassert (isThreadRunning());
  58
  59     // this needs to be a value in the future - RTFM for this method!
  60     jassert (millisecondCounterToStartAt > 0);
  61
  62     const double timeScaleFactor = 1000.0 / samplesPerSecondForBuffer;
  63
  64     MidiBuffer::Iterator i (buffer);
  65
  66     const uint8* data;
  67     int len, time;
  68
  69     while (i.getNextEvent (data, len, time))
  70     {
  71         const double eventTime = millisecondCounterToStartAt + timeScaleFactor * time;
  72
  73         PendingMessage* const m = new PendingMessage (data, len, eventTime);
  74
  75         const ScopedLock sl (lock);
  76
  77         if (firstMessage == nullptr || firstMessage->message.getTimeStamp() > eventTime)
  78         {
  79             m->next = firstMessage;
  80             firstMessage = m;
  81         }
  82         else
  83         {
  84             PendingMessage* mm = firstMessage;
  85
  86             while (mm->next != nullptr && mm->next->message.getTimeStamp() <= eventTime)
  87                 mm = mm->next;
  88
  89             m->next = mm->next;
  90             mm->next = m;
  91         }
  92     }
  93
  94     notify();
  95 }
  96
  97 void MidiOutput::clearAllPendingMessages()
  98 {
  99     const ScopedLock sl (lock);
 100
 101     while (firstMessage != nullptr)
 102     {
 103         PendingMessage* const m = firstMessage;
 104         firstMessage = firstMessage->next;
 105         delete m;
 106     }
 107 }
 108
 109 void MidiOutput::startBackgroundThread()
 110 {
 111     startThread (9);
 112 }
 113
 114 void MidiOutput::stopBackgroundThread()
 115 {
 116     stopThread (5000);
 117 }
 118
 119 void MidiOutput::run()
 120 {
 121     while (! threadShouldExit())
 122     {
 123         uint32 now = Time::getMillisecondCounter();
 124         uint32 eventTime = 0;
 125         uint32 timeToWait = 500;
 126
 127         PendingMessage* message;
 128
 129         {
 130             const ScopedLock sl (lock);
 131             message = firstMessage;
 132
 133             if (message != nullptr)
 134             {
 135                 eventTime = roundToInt (message->message.getTimeStamp());
 136
 137                 if (eventTime > now + 20)
 138                 {
 139                     timeToWait = eventTime - (now + 20);
 140                     message = nullptr;
 141                 }
 142                 else
 143                 {
 144                     firstMessage = message->next;
 145                 }
 146             }
 147         }
 148
 149         if (message != nullptr)
 150         {
 151             if (eventTime > now)
 152             {
 153                 Time::waitForMillisecondCounter (eventTime);
 154
 155                 if (threadShouldExit())
 156                     break;
 157             }
 158
 159             if (eventTime > now - 200)
 160                 sendMessageNow (message->message);
 161
 162             delete message;
 163         }
 164         else
 165         {
 166             jassert (timeToWait < 1000 * 30);
 167             wait (timeToWait);
 168         }
 169     }
 170
 171     clearAllPendingMessages();
 172 }
 173
 174
 175 END_JUCE_NAMESPACE