diff -r 836adbf7a2cd -r 3317bb8137f4 jdk/src/java.base/share/classes/java/util/zip/CRC32.java --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/jdk/src/java.base/share/classes/java/util/zip/CRC32.java Sun Aug 17 15:54:13 2014 +0100 @@ -0,0 +1,139 @@ +/* + * Copyright (c) 1996, 2013, 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; +import sun.nio.ch.DirectBuffer; + +/** + * A class that can be used to compute the CRC-32 of a data stream. + * + *

Passing a {@code null} argument to a method in this class will cause + * a {@link NullPointerException} to be thrown. + * + * @see Checksum + * @author David Connelly + */ +public +class CRC32 implements Checksum { + private int crc; + + /** + * Creates a new CRC32 object. + */ + public CRC32() { + } + + + /** + * Updates the CRC-32 checksum with the specified byte (the low + * eight bits of the argument b). + * + * @param b the byte to update the checksum with + */ + public void update(int b) { + crc = update(crc, b); + } + + /** + * Updates the CRC-32 checksum with the specified array of bytes. + * + * @throws ArrayIndexOutOfBoundsException + * if {@code off} is negative, or {@code len} is negative, + * or {@code off+len} is greater than the length of the + * array {@code b} + */ + public void update(byte[] b, int off, int len) { + if (b == null) { + throw new NullPointerException(); + } + if (off < 0 || len < 0 || off > b.length - len) { + throw new ArrayIndexOutOfBoundsException(); + } + crc = updateBytes(crc, b, off, len); + } + + /** + * Updates the CRC-32 checksum with the specified array of bytes. + * + * @param b the array of bytes to update the checksum with + */ + public void update(byte[] b) { + crc = updateBytes(crc, b, 0, b.length); + } + + /** + * Updates the checksum with the bytes from the specified buffer. + * + * The checksum is updated using + * buffer.{@link java.nio.Buffer#remaining() remaining()} + * bytes starting at + * buffer.{@link java.nio.Buffer#position() position()} + * Upon return, the buffer's position will + * be updated to its limit; its limit will not have been changed. + * + * @param buffer the ByteBuffer to update the checksum with + * @since 1.8 + */ + 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 instanceof DirectBuffer) { + crc = updateByteBuffer(crc, ((DirectBuffer)buffer).address(), pos, rem); + } else if (buffer.hasArray()) { + crc = updateBytes(crc, buffer.array(), pos + buffer.arrayOffset(), rem); + } else { + byte[] b = new byte[rem]; + buffer.get(b); + crc = updateBytes(crc, b, 0, b.length); + } + buffer.position(limit); + } + + /** + * Resets CRC-32 to initial value. + */ + public void reset() { + crc = 0; + } + + /** + * Returns CRC-32 value. + */ + public long getValue() { + return (long)crc & 0xffffffffL; + } + + private native static int update(int crc, int b); + private native static int updateBytes(int crc, byte[] b, int off, int len); + + private native static int updateByteBuffer(int adler, long addr, + int off, int len); +}