Fix voxel stream decompression.

Decompression of image from voxels in stream mode was flawed.
The base offset, which was used to copy decompressed data to result
array, was wrong. We used quantization voxel plane dimensions to
calculate it, instead of dataset plane dimensions.

src/main/java/azgracompress/compression/CompressionOptions.java

@@ -63,7 +63,7 @@ public class CompressionOptions {
     private boolean verbose = false;
 
     public CompressionOptions() {
-        int cores = Runtime.getRuntime().availableProcessors();
+        final int cores = Runtime.getRuntime().availableProcessors();
         this.workerCount = (cores / 2);
     }
 

src/main/java/azgracompress/compression/VQImageDecompressor.java

@@ -412,19 +412,23 @@ public class VQImageDecompressor extends CompressorDecompressorBase implements I
     @Override
     public short[] decompressStreamMode(final DataInputStream compressedStream,
                                         final QCMPFileHeader header) throws ImageDecompressionException {
-
         final short[] buffer = new short[(int) header.getImageDims().multiplyTogether()];
         if (header.getQuantizationType() == QuantizationType.Vector3D) {
             final V3i voxelDim = new V3i(header.getVectorSizeX(), header.getVectorSizeY(), header.getVectorSizeZ());
 
             decompressVoxelsStreamModeImpl(compressedStream, header, (voxel, voxelData, planeOffset) -> {
-                final ImageU16Dataset currentVoxelLayer = voxel.reconstructFromVoxelsToDataset(voxelDim, voxelData);
-                int offset = planeOffset * (voxelDim.getX() * voxelDim.getY());
 
-                for (int layer = 0; layer < voxel.getDims().getZ(); layer++) {
-                    final short[] voxelLayerData = currentVoxelLayer.getPlaneData(layer);
-                    System.arraycopy(voxelLayerData, 0, buffer, offset, voxelLayerData.length);
-                    offset += voxelLayerData.length;
+                final ImageU16Dataset decompressedVoxel = voxel.reconstructFromVoxelsToDataset(voxelDim, voxelData);
+                assert (decompressedVoxel.getPlaneCount() == voxel.getDims().getZ());
+                final int expectedVoxelPlaneSize = header.getImageSizeX() * header.getImageSizeY();
+
+                final int baseOffset = planeOffset * expectedVoxelPlaneSize;
+
+                for (int voxelLayerIndex = 0; voxelLayerIndex < decompressedVoxel.getPlaneCount(); voxelLayerIndex++) {
+                    final short[] voxelLayerData = decompressedVoxel.getPlaneData(voxelLayerIndex);
+                    assert (voxelLayerData.length == expectedVoxelPlaneSize);
+                    final int bufferPos = baseOffset + (voxelLayerIndex * expectedVoxelPlaneSize);
+                    System.arraycopy(voxelLayerData, 0, buffer, bufferPos, voxelLayerData.length);
                 }
             });
             return buffer;