| /* |
| * 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 |
| * particular file as subject to the "Classpath" exception as provided |
| * by Oracle in the LICENSE file that accompanied this code. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * 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 { |
| |
| /** |
| * 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 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 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(); |
| |
| /** |
| * Resets the checksum to its initial value. |
| */ |
| public void reset(); |
| } |