src/java.base/share/classes/java/util/zip/Checksum.java

@@ -1,7 +1,7 @@
 /*
- * Copyright (c) 1996, 1999, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1996, 2014, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License version 2 only, as
  * published by the Free Software Foundation.  Oracle designates this

@@ -20,37 +20,113 @@
  *
  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  * or visit www.oracle.com if you need additional information or have any
  * questions.
  */
-
 package java.util.zip;
 
+import java.nio.ByteBuffer;
+
 /**
  * An interface representing a data checksum.
  *
  * @author      David Connelly
  */
-public
-interface Checksum {
+public interface Checksum {
+
     /**
      * Updates the current checksum with the specified byte.
      *
      * @param b the byte to update the checksum with
      */
     public void update(int b);
 
     /**
      * Updates the current checksum with the specified array of bytes.
+     *
+     * @implSpec This default implementation is equal to calling
+     * {@code update(b, 0, b.length)}.
+     *
+     * @param b the array of bytes to update the checksum with
+     * 
+     * @throws NullPointerException
+     *         if {@code b} is {@code null}
+     * 
+     * @since 1.9
+     */
+    default public void update(byte[] b) {
+        update(b, 0, b.length);
+    }
+
+    /**
+     * Updates the current checksum with the specified array of bytes.
+     *
      * @param b the byte array to update the checksum with
      * @param off the start offset of the data
      * @param len the number of bytes to use for the update
      */
     public void update(byte[] b, int off, int len);
 
     /**
+     * Updates the current checksum with the bytes from the specified buffer.
+     *
+     * The checksum is updated with the remaining bytes in the buffer, starting
+     * at the buffer's position. Upon return, the buffer's position will be
+     * updated to its limit; its limit will not have been changed.
+     *
+     * @apiNote For best performance with DirectByteBuffer and other ByteBuffer
+     * implementations without a backing array implementers of this interface
+     * should override this method.
+     *
+     * @implSpec The default implementation has the following behavior.<br>
+     * For ByteBuffers backed by an accessible byte array.      
+     * <pre>{@code
+     * update(buffer.array(),
+     *        buffer.position() + buffer.arrayOffset(),
+     *        buffer.remaining());
+     * }</pre>
+     * For ByteBuffers not backed by an accessible byte array.
+     * <pre>{@code
+     * byte[] b = new byte[Math.min(buffer.remaining(), 4096)];
+     * while (buffer.hasRemaining()) {
+     *     int length = Math.min(buffer.remaining(), b.length);
+     *     buffer.get(b, 0, length);
+     *     update(b, 0, length);
+     * }
+     * }</pre>
+     *
+     * @param buffer the ByteBuffer to update the checksum with
+     * 
+     * @throws NullPointerException
+     *         if {@code buffer} is {@code null}
+     * 
+     * @since 1.9
+     */
+    default public void update(ByteBuffer buffer) {
+        int pos = buffer.position();
+        int limit = buffer.limit();
+        assert (pos <= limit);
+        int rem = limit - pos;
+        if (rem <= 0) {
+            return;
+        }
+        if (buffer.hasArray()) {
+            update(buffer.array(), pos + buffer.arrayOffset(), rem);
+        } else {
+            byte[] b = new byte[Math.min(buffer.remaining(), 4096)];
+            while (buffer.hasRemaining()) {
+                int length = Math.min(buffer.remaining(), b.length);
+                buffer.get(b, 0, length);
+                update(b, 0, length);                
+            }
+        }
+        buffer.position(limit);
+    }
+
+    /**
      * Returns the current checksum value.
+     *
      * @return the current checksum value
      */
     public long getValue();
 
     /**