juce/source/src/audio/audio_sources/juce_AudioTransportSource.h

   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 #ifndef __JUCE_AUDIOTRANSPORTSOURCE_JUCEHEADER__
  27 #define __JUCE_AUDIOTRANSPORTSOURCE_JUCEHEADER__
  28
  29 #include "juce_BufferingAudioSource.h"
  30 #include "juce_ResamplingAudioSource.h"
  31 #include "../../events/juce_ChangeBroadcaster.h"
  32
  33
  34 //==============================================================================
  35 /**
  36     An AudioSource that takes a PositionableAudioSource and allows it to be
  37     played, stopped, started, etc.
  38
  39     This can also be told use a buffer and background thread to read ahead, and
  40     if can correct for different sample-rates.
  41
  42     You may want to use one of these along with an AudioSourcePlayer and AudioIODevice
  43     to control playback of an audio file.
  44
  45     @see AudioSource, AudioSourcePlayer
  46 */
  47 class JUCE_API  AudioTransportSource  : public PositionableAudioSource,
  48                                         public ChangeBroadcaster
  49 {
  50 public:
  51     //==============================================================================
  52     /** Creates an AudioTransportSource.
  53
  54         After creating one of these, use the setSource() method to select an input source.
  55     */
  56     AudioTransportSource();
  57
  58     /** Destructor. */
  59     ~AudioTransportSource();
  60
  61     //==============================================================================
  62     /** Sets the reader that is being used as the input source.
  63
  64         This will stop playback, reset the position to 0 and change to the new reader.
  65
  66         The source passed in will not be deleted by this object, so must be managed by
  67         the caller.
  68
  69         @param newSource                        the new input source to use. This may be zero
  70         @param readAheadBufferSize              a size of buffer to use for reading ahead. If this
  71                                                 is zero, no reading ahead will be done; if it's
  72                                                 greater than zero, a BufferingAudioSource will be used
  73                                                 to do the reading-ahead
  74         @param sourceSampleRateToCorrectFor     if this is non-zero, it specifies the sample
  75                                                 rate of the source, and playback will be sample-rate
  76                                                 adjusted to maintain playback at the correct pitch. If
  77                                                 this is 0, no sample-rate adjustment will be performed
  78         @param maxNumChannels                   the maximum number of channels that may need to be played
  79     */
  80     void setSource (PositionableAudioSource* newSource,
  81                     int readAheadBufferSize = 0,
  82                     double sourceSampleRateToCorrectFor = 0.0,
  83                     int maxNumChannels = 2);
  84
  85     //==============================================================================
  86     /** Changes the current playback position in the source stream.
  87
  88         The next time the getNextAudioBlock() method is called, this
  89         is the time from which it'll read data.
  90
  91         @see getPosition
  92     */
  93     void setPosition (double newPosition);
  94
  95     /** Returns the position that the next data block will be read from
  96
  97         This is a time in seconds.
  98     */
  99     double getCurrentPosition() const;
 100
 101     /** Returns the stream's length in seconds. */
 102     double getLengthInSeconds() const;
 103
 104     /** Returns true if the player has stopped because its input stream ran out of data.
 105     */
 106     bool hasStreamFinished() const noexcept             { return inputStreamEOF; }
 107
 108     //==============================================================================
 109     /** Starts playing (if a source has been selected).
 110
 111         If it starts playing, this will send a message to any ChangeListeners
 112         that are registered with this object.
 113     */
 114     void start();
 115
 116     /** Stops playing.
 117
 118         If it's actually playing, this will send a message to any ChangeListeners
 119         that are registered with this object.
 120     */
 121     void stop();
 122
 123     /** Returns true if it's currently playing. */
 124     bool isPlaying() const noexcept     { return playing; }
 125
 126     //==============================================================================
 127     /** Changes the gain to apply to the output.
 128
 129         @param newGain  a factor by which to multiply the outgoing samples,
 130                         so 1.0 = 0dB, 0.5 = -6dB, 2.0 = 6dB, etc.
 131     */
 132     void setGain (float newGain) noexcept;
 133
 134     /** Returns the current gain setting.
 135
 136         @see setGain
 137     */
 138     float getGain() const noexcept      { return gain; }
 139
 140
 141     //==============================================================================
 142     /** Implementation of the AudioSource method. */
 143     void prepareToPlay (int samplesPerBlockExpected, double sampleRate);
 144
 145     /** Implementation of the AudioSource method. */
 146     void releaseResources();
 147
 148     /** Implementation of the AudioSource method. */
 149     void getNextAudioBlock (const AudioSourceChannelInfo& bufferToFill);
 150
 151     //==============================================================================
 152     /** Implements the PositionableAudioSource method. */
 153     void setNextReadPosition (int64 newPosition);
 154
 155     /** Implements the PositionableAudioSource method. */
 156     int64 getNextReadPosition() const;
 157
 158     /** Implements the PositionableAudioSource method. */
 159     int64 getTotalLength() const;
 160
 161     /** Implements the PositionableAudioSource method. */
 162     bool isLooping() const;
 163
 164 private:
 165     //==============================================================================
 166     PositionableAudioSource* source;
 167     ResamplingAudioSource* resamplerSource;
 168     BufferingAudioSource* bufferingSource;
 169     PositionableAudioSource* positionableSource;
 170     AudioSource* masterSource;
 171
 172     CriticalSection callbackLock;
 173     float volatile gain, lastGain;
 174     bool volatile playing, stopped;
 175     double sampleRate, sourceSampleRate;
 176     int blockSize, readAheadBufferSize;
 177     bool isPrepared, inputStreamEOF;
 178
 179     void releaseMasterResources();
 180
 181     JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (AudioTransportSource);
 182 };
 183
 184
 185 #endif   // __JUCE_AUDIOTRANSPORTSOURCE_JUCEHEADER__