Fix for AudioFormatReader::read when passing buffers with > 2 channels.

modules/juce_audio_formats/format/juce_AudioFormatReader.cpp

@@ -100,6 +100,18 @@ bool AudioFormatReader::read (int* const* destSamples,
     return true;
 }
 
+static void readChannels (AudioFormatReader& reader,
+                          int** const chans, AudioSampleBuffer* const buffer,
+                          const int startSample, const int numSamples,
+                          const int64 readerStartSample, const int numTargetChannels)
+{
+    for (int j = 0; j < numTargetChannels; ++j)
+        chans[j] = reinterpret_cast<int*> (buffer->getSampleData (j, startSample));
+
+    chans[numTargetChannels] = nullptr;
+    reader.read (chans, numTargetChannels, readerStartSample, numSamples, true);
+}
+
 void AudioFormatReader::read (AudioSampleBuffer* buffer,
                               int startSample,
                               int numSamples,
@@ -113,49 +125,51 @@ void AudioFormatReader::read (AudioSampleBuffer* buffer,
     if (numSamples > 0)
     {
         const int numTargetChannels = buffer->getNumChannels();
-        int* chans[3];
 
-        if (useReaderLeftChan == useReaderRightChan)
+        if (numTargetChannels <= 2)
         {
-            chans[0] = reinterpret_cast<int*> (buffer->getSampleData (0, startSample));
-            chans[1] = (numChannels > 1 && numTargetChannels > 1) ? reinterpret_cast<int*> (buffer->getSampleData (1, startSample)) : nullptr;
-        }
-        else if (useReaderLeftChan || (numChannels == 1))
-        {
-            chans[0] = reinterpret_cast<int*> (buffer->getSampleData (0, startSample));
-            chans[1] = nullptr;
-        }
-        else if (useReaderRightChan)
-        {
-            chans[0] = nullptr;
-            chans[1] = reinterpret_cast<int*> (buffer->getSampleData (0, startSample));
-        }
+            int* const dest0 = reinterpret_cast<int*> (buffer->getSampleData (0, startSample));
+            int* const dest1 = reinterpret_cast<int*> (numTargetChannels > 1 ? buffer->getSampleData (1, startSample) : nullptr);
+            int* chans[3];
 
-        chans[2] = nullptr;
+            if (useReaderLeftChan == useReaderRightChan)
+            {
+                chans[0] = dest0;
+                chans[1] = numChannels > 1 ? dest1 : nullptr;
+            }
+            else if (useReaderLeftChan || (numChannels == 1))
+            {
+                chans[0] = dest0;
+                chans[1] = nullptr;
+            }
+            else if (useReaderRightChan)
+            {
+                chans[0] = nullptr;
+                chans[1] = dest0;
+            }
 
-        read (chans, 2, readerStartSample, numSamples, true);
+            chans[2] = nullptr;
+            read (chans, 2, readerStartSample, numSamples, true);
 
-        if (! usesFloatingPointData)
+            // if the target's stereo and the source is mono, dupe the first channel..
+            if (numTargetChannels > 1 && (chans[0] == nullptr || chans[1] == nullptr))
+                memcpy (dest1, dest0, sizeof (float) * (size_t) numSamples);
+        }
+        else if (numTargetChannels <= 64)
         {
-            for (int j = 0; j < 2; ++j)
-            {
-                if (float* const d = reinterpret_cast <float*> (chans[j]))
-                {
-                    const float multiplier = 1.0f / 0x7fffffff;
-
-                    for (int i = 0; i < numSamples; ++i)
-                        d[i] = *reinterpret_cast<int*> (d + i) * multiplier;
-                }
-            }
+            int* chans[65];
+            readChannels (*this, chans, buffer, startSample, numSamples, readerStartSample, numTargetChannels);
         }
-
-        if (numTargetChannels > 1 && (chans[0] == nullptr || chans[1] == nullptr))
+        else
         {
-            // if this is a stereo buffer and the source was mono, dupe the first channel..
-            memcpy (buffer->getSampleData (1, startSample),
-                    buffer->getSampleData (0, startSample),
-                    sizeof (float) * (size_t) numSamples);
+            HeapBlock<int*> chans (numTargetChannels);
+            readChannels (*this, chans, buffer, startSample, numSamples, readerStartSample, numTargetChannels);
         }
+
+        if (! usesFloatingPointData)
+            for (int j = 0; j < numTargetChannels; ++j)
+                if (float* const d = buffer->getSampleData (j, startSample))
+                    FloatVectorOperations::convertFixedToFloat (d, reinterpret_cast<const int*> (d), 1.0f / 0x7fffffff, numSamples);
     }
 }