juce/source/src/audio/audio_file_formats/juce_AudioSubsectionReader.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_AUDIOSUBSECTIONREADER_JUCEHEADER__
  27 #define __JUCE_AUDIOSUBSECTIONREADER_JUCEHEADER__
  28
  29 #include "juce_AudioFormatReader.h"
  30
  31
  32 //==============================================================================
  33 /**
  34     This class is used to wrap an AudioFormatReader and only read from a
  35     subsection of the file.
  36
  37     So if you have a reader which can read a 1000 sample file, you could wrap it
  38     in one of these to only access, e.g. samples 100 to 200, and any samples
  39     outside that will come back as 0. Accessing sample 0 from this reader will
  40     actually read the first sample from the other's subsection, which might
  41     be at a non-zero position.
  42
  43     @see AudioFormatReader
  44 */
  45 class JUCE_API  AudioSubsectionReader  : public AudioFormatReader
  46 {
  47 public:
  48     //==============================================================================
  49     /** Creates a AudioSubsectionReader for a given data source.
  50
  51         @param sourceReader             the source reader from which we'll be taking data
  52         @param subsectionStartSample    the sample within the source reader which will be
  53                                         mapped onto sample 0 for this reader.
  54         @param subsectionLength         the number of samples from the source that will
  55                                         make up the subsection. If this reader is asked for
  56                                         any samples beyond this region, it will return zero.
  57         @param deleteSourceWhenDeleted  if true, the sourceReader object will be deleted when
  58                                         this object is deleted.
  59     */
  60     AudioSubsectionReader (AudioFormatReader* sourceReader,
  61                            int64 subsectionStartSample,
  62                            int64 subsectionLength,
  63                            bool deleteSourceWhenDeleted);
  64
  65     /** Destructor. */
  66     ~AudioSubsectionReader();
  67
  68
  69     //==============================================================================
  70     bool readSamples (int** destSamples, int numDestChannels, int startOffsetInDestBuffer,
  71                       int64 startSampleInFile, int numSamples);
  72
  73     void readMaxLevels (int64 startSample,
  74                         int64 numSamples,
  75                         float& lowestLeft,
  76                         float& highestLeft,
  77                         float& lowestRight,
  78                         float& highestRight);
  79
  80
  81 private:
  82     //==============================================================================
  83     AudioFormatReader* const source;
  84     int64 startSample, length;
  85     const bool deleteSourceWhenDeleted;
  86
  87     JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (AudioSubsectionReader);
  88 };
  89
  90 #endif   // __JUCE_AUDIOSUBSECTIONREADER_JUCEHEADER__