juce/source/src/audio/audio_file_formats/juce_AudioSubsectionReader.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_AudioSubsectionReader.h"
  31
  32
  33 //==============================================================================
  34 AudioSubsectionReader::AudioSubsectionReader (AudioFormatReader* const source_,
  35                                               const int64 startSample_,
  36                                               const int64 length_,
  37                                               const bool deleteSourceWhenDeleted_)
  38    : AudioFormatReader (0, source_->getFormatName()),
  39      source (source_),
  40      startSample (startSample_),
  41      deleteSourceWhenDeleted (deleteSourceWhenDeleted_)
  42 {
  43     length = jmin (jmax ((int64) 0, source->lengthInSamples - startSample), length_);
  44
  45     sampleRate = source->sampleRate;
  46     bitsPerSample = source->bitsPerSample;
  47     lengthInSamples = length;
  48     numChannels = source->numChannels;
  49     usesFloatingPointData = source->usesFloatingPointData;
  50 }
  51
  52 AudioSubsectionReader::~AudioSubsectionReader()
  53 {
  54     if (deleteSourceWhenDeleted)
  55         delete source;
  56 }
  57
  58 //==============================================================================
  59 bool AudioSubsectionReader::readSamples (int** destSamples, int numDestChannels, int startOffsetInDestBuffer,
  60                                          int64 startSampleInFile, int numSamples)
  61 {
  62     if (startSampleInFile + numSamples > length)
  63     {
  64         for (int i = numDestChannels; --i >= 0;)
  65             if (destSamples[i] != nullptr)
  66                 zeromem (destSamples[i], sizeof (int) * numSamples);
  67
  68         numSamples = jmin (numSamples, (int) (length - startSampleInFile));
  69
  70         if (numSamples <= 0)
  71             return true;
  72     }
  73
  74     return source->readSamples (destSamples, numDestChannels, startOffsetInDestBuffer,
  75                                 startSampleInFile + startSample, numSamples);
  76 }
  77
  78 void AudioSubsectionReader::readMaxLevels (int64 startSampleInFile,
  79                                            int64 numSamples,
  80                                            float& lowestLeft,
  81                                            float& highestLeft,
  82                                            float& lowestRight,
  83                                            float& highestRight)
  84 {
  85     startSampleInFile = jmax ((int64) 0, startSampleInFile);
  86     numSamples = jmax ((int64) 0, jmin (numSamples, length - startSampleInFile));
  87
  88     source->readMaxLevels (startSampleInFile + startSample, numSamples,
  89                            lowestLeft, highestLeft,
  90                            lowestRight, highestRight);
  91 }
  92
  93 END_JUCE_NAMESPACE