Create no-op byte data impl

Author: Col-E

src/main/java/software/coley/lljzip/util/ByteDataUtil.java

@@ -298,8 +298,8 @@ public static byte[] readArray(ByteData data, int start, int len) {
 	 */
 	public static ByteBuffer sliceExact(ByteBuffer data, int start, int end) {
 		ByteBuffer slice = data.slice();
-		slice = ((ByteBuffer) ((Buffer)slice).position(start)).slice();
-		((Buffer)slice).limit(end - start);
+		slice = ((ByteBuffer) ((Buffer) slice).position(start)).slice();
+		((Buffer) slice).limit(end - start);
 		return slice.order(data.order());
 	}
 

src/main/java/software/coley/lljzip/util/NoopByteData.java

@@ -0,0 +1,66 @@
+package software.coley.lljzip.util;
+
+import java.io.OutputStream;
+
+/**
+ * Empty file that yields {@code 0} for everything.
+ *
+ * @author Matt Coley
+ */
+public class NoopByteData implements ByteData {
+	/**
+	 * Shared instance.
+	 */
+	public static final NoopByteData INSTANCE = new NoopByteData();
+
+	private NoopByteData() {
+		// deny construction
+	}
+
+	@Override
+	public boolean isClosed() {
+		return false;
+	}
+
+	@Override
+	public int getInt(long position) {
+		return 0;
+	}
+
+	@Override
+	public long getLong(long position) {
+		return 0;
+	}
+
+	@Override
+	public short getShort(long position) {
+		return 0;
+	}
+
+	@Override
+	public byte get(long position) {
+		return 0;
+	}
+
+	@Override
+	public void get(long position, byte[] buffer, int off, int len) {
+	}
+
+	@Override
+	public void transferTo(OutputStream out, byte[] buffer) {
+	}
+
+	@Override
+	public ByteData slice(long startIndex, long endIndex) {
+		return this;
+	}
+
+	@Override
+	public long length() {
+		return 0;
+	}
+
+	@Override
+	public void close() {
+	}
+}