Merge pull request #525 from jamesmudd/issue-523

Add Time Data Type support

Author: jamesmudd

Diff for: jhdf/src/main/java/io/jhdf/object/datatype/DataType.java

@@ -15,12 +15,15 @@
 import io.jhdf.exceptions.UnsupportedHdfException;
 import io.jhdf.storage.HdfBackingStorage;
 import io.jhdf.storage.HdfFileChannel;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 import java.nio.ByteBuffer;
 import java.util.BitSet;
 
 public abstract class DataType {
 
+	private static final Logger logger = LoggerFactory.getLogger(DataType.class);
 	private final int version;
 	private final int dataClass;
 	private final int size; // In bytes
@@ -42,7 +45,9 @@ public static DataType readDataType(ByteBuffer bb) {
 		int version = Utils.bitsToInt(classAndVersion, 4, 4);
 		int dataClass = Utils.bitsToInt(classAndVersion, 0, 4);
 
-		if (version == 0 || version > 3) {
+		if (version == 0) {
+			logger.warn("Datatype version 0 detected this is out of spec, attempting to read anyway");
+		} else if (version > 3) {
 			throw new HdfException("Unrecognized datatype version '" + version + "' detected");
 		}
 
@@ -55,8 +60,8 @@ public static DataType readDataType(ByteBuffer bb) {
 				return new FixedPoint(bb);
 			case FloatingPoint.CLASS_ID: // Floating point
 				return new FloatingPoint(bb);
-			case 2: // Time
-				throw new UnsupportedHdfException("Time data type is not yet supported");
+			case TimeDataType.CLASS_ID: // Time
+				return new TimeDataType(bb);
 			case StringData.CLASS_ID: // String
 				return new StringData(bb);
 			case BitField.CLASS_ID: // Bit field

Diff for: jhdf/src/main/java/io/jhdf/object/datatype/TimeDataType.java

@@ -0,0 +1,72 @@
+/*
+ * This file is part of jHDF. A pure Java library for accessing HDF5 files.
+ *
+ * https://jhdf.io
+ *
+ * Copyright (c) 2025 James Mudd
+ *
+ * MIT License see 'LICENSE' file
+ */
+package io.jhdf.object.datatype;
+
+import io.jhdf.storage.HdfBackingStorage;
+
+import java.lang.reflect.Array;
+import java.nio.ByteBuffer;
+import java.nio.ByteOrder;
+
+import static io.jhdf.Utils.stripLeadingIndex;
+
+public class TimeDataType extends DataType implements OrderedDataType {
+	public static final int CLASS_ID = 2;
+
+	private final ByteOrder order;
+	private final short bitPrecision;
+
+	public TimeDataType(ByteBuffer bb) {
+		super(bb);
+
+		if (classBits.get(0)) {
+			order = ByteOrder.BIG_ENDIAN;
+		} else {
+			order = ByteOrder.LITTLE_ENDIAN;
+		}
+
+		bitPrecision = bb.getShort();
+	}
+
+	@Override
+	public ByteOrder getByteOrder() {
+		return order;
+	}
+	@Override
+	public Class<?> getJavaType() {
+		return byte[].class;
+	}
+
+	@Override
+	public Object fillData(ByteBuffer buffer, int[] dimensions, HdfBackingStorage hdfBackingStorage) {
+		final Object data = Array.newInstance(getJavaType(), dimensions);
+		fillData(data, dimensions, buffer.order(getByteOrder()));
+		return data;
+	}
+
+	private void fillData(Object data, int[] dims, ByteBuffer buffer) {
+		if (dims.length > 1) {
+			for (int i = 0; i < dims[0]; i++) {
+				Object newArray = Array.get(data, i);
+				fillData(newArray, stripLeadingIndex(dims), buffer);
+			}
+		} else {
+			for (int i = 0; i < Array.getLength(data); i++) {
+				byte[] bytes = new byte[getSize()];
+				buffer.get(bytes);
+				Array.set(data, i, bytes);
+			}
+		}
+	}
+
+	public short getBitPrecision() {
+		return bitPrecision;
+	}
+}