/*
* @(#)CRC16.java 1.6 95/09/06 Chuck McManis
*
* Copyright (c) 1994 Sun Microsystems, Inc. All Rights Reserved.
*
* Permission to use, copy, modify, and distribute this software
* and its documentation for NON-COMMERCIAL purposes and without
* fee is hereby granted provided that this copyright notice
* appears in all copies. Please refer to the file "copyright.html"
* for further important copyright and licensing information.
*
* SUN MAKES NO REPRESENTATIONS OR WARRANTIES ABOUT THE SUITABILITY OF
* THE SOFTWARE, EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED
* TO THE IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
* PARTICULAR PURPOSE, OR NON-INFRINGEMENT. SUN SHALL NOT BE LIABLE FOR
* ANY DAMAGES SUFFERED BY LICENSEE AS A RESULT OF USING, MODIFYING OR
* DISTRIBUTING THIS SOFTWARE OR ITS DERIVATIVES.
*/
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;
}
}