/*
* Copyright (c) 2000, 2007, 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.
*/
/*
*
* (C) Copyright IBM Corp. 1999 All Rights Reserved.
* Copyright 1997 The Open Group Research Institute. All rights reserved.
*/
package sun.security.krb5.internal;
import sun.security.krb5.Confounder;
public class LocalSeqNumber implements SeqNumber {
private int lastSeqNumber;
public LocalSeqNumber() {
randInit();
}
public LocalSeqNumber(int start) {
init(start);
}
public LocalSeqNumber(Integer start) {
init(start.intValue());
}
public synchronized void randInit() {
/*
* Sequence numbers fall in the range 0 through 2^32 - 1 and wrap
* to zero following the value 2^32 - 1.
* Previous implementations used signed sequence numbers.
* Workaround implementation incompatibilities by not generating
* initial sequence numbers greater than 2^30, as done
* in MIT distribution.
*/
// get the random confounder
byte[] data = Confounder.bytes(4);
data[0] = (byte)(data[0] & 0x3f);
int result = ((data[3] & 0xff) |
((data[2] & 0xff) << 8) |
((data[1] & 0xff) << 16) |
((data[0] & 0xff) << 24));
if (result == 0) {
result = 1;
}
lastSeqNumber = result;
}
public synchronized void init(int start) {
lastSeqNumber = start;
}
public synchronized int current() {
return lastSeqNumber;
}
public synchronized int next() {
return lastSeqNumber + 1;
}
public synchronized int step() {
return ++lastSeqNumber;
}
}