Move most of the 2D block loading to loaders.

This change allows us to save memory on loading, by skipping one copy
step. Also loading is a bit faster. Next-up is 1D row vector loading.

src/main/java/azgracompress/io/loader/IPlaneLoader.java

 package azgracompress.io.loader;
 
 import azgracompress.data.Range;
+import azgracompress.data.V2i;
 import azgracompress.data.V3i;
 
 import java.io.IOException;
@@ -9,6 +10,13 @@ import java.io.IOException;
  * Interface for dataset loaders.
  */
 public interface IPlaneLoader {
+    /**
+     * Get dimensions of the image, for which the loader was created.
+     *
+     * @return Image of the loader image.
+     */
+    V3i getImageDimensions();
+
     /**
      * Load specified plane data.
      *
@@ -36,6 +44,27 @@ public interface IPlaneLoader {
      */
     int[] loadAllPlanesU16Data() throws IOException;
 
+    /**
+     * Load blocks from the entire dataset.
+     *
+     * @param blockDim Dimensions of the 2D block. (Matrix)
+     * @return Block data from the entire dataset.
+     * @throws IOException When fails to load plane data.
+     */
+    default int[][] loadBlocks(final V2i blockDim) throws IOException {
+        return loadBlocks(blockDim, new Range<>(0, getImageDimensions().getZ()));
+    }
+
+    /**
+     * Load blocks from specified plane range in the dataset.
+     *
+     * @param blockDim   Dimensions of the 2D block. (Matrix)
+     * @param planeRange Source plane range.
+     * @return Block data from the specified plane range.
+     * @throws IOException When fails to load plane data.
+     */
+    int[][] loadBlocks(final V2i blockDim, final Range<Integer> planeRange) throws IOException;
+
     /**
      * Load voxels from entire dataset.
      *
@@ -43,15 +72,17 @@ public interface IPlaneLoader {
      * @return Voxel data from the entire dataset.
      * @throws IOException when fails to load plane data.
      */
-    int[][] loadVoxels(final V3i voxelDim) throws IOException;
+    default int[][] loadVoxels(final V3i voxelDim) throws IOException {
+        return loadVoxels(voxelDim, new Range<>(0, getImageDimensions().getZ()));
+    }
 
     /**
-     * Load voxels from specified plane range in the datasIet.
+     * Load voxels from specified plane range in the dataset.
      * Plane range should be divisible by `voxelDim.getZ()`
      *
      * @param voxelDim   Voxel dimensions.
-     * @param planeRange Source voxel dimensions.
-     * @return Voxel data from the entire dataset.
+     * @param planeRange Source plane range.
+     * @return Voxel data from the specified plane range.
      * @throws IOException when fails to load plane data.
      */
     int[][] loadVoxels(final V3i voxelDim, final Range<Integer> planeRange) throws IOException;

src/main/java/azgracompress/io/loader/ImageJBufferLoader.java

 package azgracompress.io.loader;
 
 import azgracompress.data.Range;
+import azgracompress.data.V2i;
 import azgracompress.data.V3i;
 import azgracompress.io.BufferInputData;
 import azgracompress.io.InputData;
@@ -87,8 +88,8 @@ public final class ImageJBufferLoader extends BasicLoader implements IPlaneLoade
     }
 
     @Override
-    public int[][] loadVoxels(final V3i voxelDim) throws IOException {
-        return loadVoxels(voxelDim, new Range<>(0, bufferInputData.getDimensions().getZ()));
+    public int[][] loadBlocks(V2i blockDim, Range<Integer> planeRange) throws IOException {
+        return loadBlocksImplByValueAt(blockDim, planeRange);
     }
 
     @Override

src/main/java/azgracompress/io/loader/RawDataLoader.java

 package azgracompress.io.loader;
 
 import azgracompress.data.Range;
+import azgracompress.data.V2i;
 import azgracompress.data.V3i;
 import azgracompress.io.FileInputData;
 import azgracompress.utilities.TypeConverter;
@@ -117,8 +118,8 @@ public final class RawDataLoader extends BasicLoader implements IPlaneLoader {
     }
 
     @Override
-    public int[][] loadVoxels(final V3i voxelDim) throws IOException {
-        return loadVoxels(voxelDim, new Range<>(0, inputDataInfo.getDimensions().getZ()));
+    public int[][] loadBlocks(V2i blockDim, Range<Integer> planeRange) throws IOException {
+        return loadBlocksImplLoadPlaneData(blockDim, planeRange);
     }
 
     @Override

src/main/java/azgracompress/io/loader/SCIFIOLoader.java

@@ -2,6 +2,7 @@ package azgracompress.io.loader;
 
 import azgracompress.ScifioWrapper;
 import azgracompress.data.Range;
+import azgracompress.data.V2i;
 import azgracompress.data.V3i;
 import azgracompress.io.FileInputData;
 import azgracompress.utilities.TypeConverter;
@@ -12,10 +13,13 @@ import java.io.IOException;
 import java.util.Arrays;
 
 public final class SCIFIOLoader extends BasicLoader implements IPlaneLoader {
-
     private final FileInputData inputDataInfo;
     private final Reader reader;
 
+    // Current plane buffer
+    private int currentPlaneIndex = -1;
+    private int[] currentPlaneData;
+
     /**
      * Create SCIFIO reader from input file.
      *
@@ -29,6 +33,26 @@ public final class SCIFIOLoader extends BasicLoader implements IPlaneLoader {
         this.reader = ScifioWrapper.getReader(this.inputDataInfo.getFilePath());
     }
 
+//    @Override
+//    protected int valueAt(int plane, int offset) {
+//        // TODO(Moravec): Measure if caching the current plane byte buffer make any sense.
+//        if (plane != currentPlaneIndex) {
+//            currentPlaneIndex = plane;
+//            try {
+//                currentPlaneData = TypeConverter.unsignedShortBytesToIntArray(reader.openPlane(0, currentPlaneIndex).getBytes());
+//            } catch (FormatException e) {
+//                System.err.println(e.toString());
+//                e.printStackTrace();
+//                assert (false) : "FormatException in SCIFIOLoader::valueAt()";
+//            } catch (IOException e) {
+//                System.err.println(e.toString());
+//                e.printStackTrace();
+//                assert (false) : "IOException in SCIFIOLoader::valueAt()";
+//            }
+//        }
+//        return currentPlaneData[offset];
+//    }
+
     @Override
     public int[] loadPlaneData(final int plane) throws IOException {
         byte[] planeBytes;
@@ -106,8 +130,8 @@ public final class SCIFIOLoader extends BasicLoader implements IPlaneLoader {
     }
 
     @Override
-    public int[][] loadVoxels(final V3i voxelDim) throws IOException {
-        return loadVoxels(voxelDim, new Range<>(0, inputDataInfo.getDimensions().getZ()));
+    public int[][] loadBlocks(V2i blockDim, Range<Integer> planeRange) throws IOException {
+        return loadBlocksImplLoadPlaneData(blockDim, planeRange);
     }
 
     @Override