/*
* Copyright (c) 1994, 1995, 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 sun.misc;
/**
* The CRC-16 class calculates a 16 bit cyclic redundancy check of a set
* of bytes. This error detecting code is used to determine if bit rot
* has occured in a byte stream.
*/
public class CRC16 {
/** value contains the currently computed CRC, set it to 0 initally */
public int value;
public CRC16() {
value = 0;
}
/** update CRC with byte b */
public void update(byte aByte) {
int a, b;
a = (int) aByte;
for (int count = 7; count >=0; count--) {
a = a << 1;
b = (a >>> 8) & 1;
if ((value & 0x8000) != 0) {
value = ((value << 1) + b) ^ 0x1021;
} else {
value = (value << 1) + b;
}
}
value = value & 0xffff;
return;
}
/** reset CRC value to 0 */
public void reset() {
value = 0;
}
}