001: /* ====================================================================
002: * The Jcorporate Apache Style Software License, Version 1.2 05-07-2002
003: *
004: * Copyright (c) 1995-2002 Jcorporate Ltd. All rights reserved.
005: *
006: * Redistribution and use in source and binary forms, with or without
007: * modification, are permitted provided that the following conditions
008: * are met:
009: *
010: * 1. Redistributions of source code must retain the above copyright
011: * notice, this list of conditions and the following disclaimer.
012: *
013: * 2. Redistributions in binary form must reproduce the above copyright
014: * notice, this list of conditions and the following disclaimer in
015: * the documentation and/or other materials provided with the
016: * distribution.
017: *
018: * 3. The end-user documentation included with the redistribution,
019: * if any, must include the following acknowledgment:
020: * "This product includes software developed by Jcorporate Ltd.
021: * (http://www.jcorporate.com/)."
022: * Alternately, this acknowledgment may appear in the software itself,
023: * if and wherever such third-party acknowledgments normally appear.
024: *
025: * 4. "Jcorporate" and product names such as "Expresso" must
026: * not be used to endorse or promote products derived from this
027: * software without prior written permission. For written permission,
028: * please contact info@jcorporate.com.
029: *
030: * 5. Products derived from this software may not be called "Expresso",
031: * or other Jcorporate product names; nor may "Expresso" or other
032: * Jcorporate product names appear in their name, without prior
033: * written permission of Jcorporate Ltd.
034: *
035: * 6. No product derived from this software may compete in the same
036: * market space, i.e. framework, without prior written permission
037: * of Jcorporate Ltd. For written permission, please contact
038: * partners@jcorporate.com.
039: *
040: * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
041: * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
042: * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
043: * DISCLAIMED. IN NO EVENT SHALL JCORPORATE LTD OR ITS CONTRIBUTORS
044: * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
045: * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
046: * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
047: * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
048: * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
049: * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
050: * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
051: * SUCH DAMAGE.
052: * ====================================================================
053: *
054: * This software consists of voluntary contributions made by many
055: * individuals on behalf of the Jcorporate Ltd. Contributions back
056: * to the project(s) are encouraged when you make modifications.
057: * Please send them to support@jcorporate.com. For more information
058: * on Jcorporate Ltd. and its products, please see
059: * <http://www.jcorporate.com/>.
060: *
061: * Portions of this software are based upon other open source
062: * products and are subject to their respective licenses.
063: */
064:
065: package com.jcorporate.expresso.core.misc;
066:
067: /**
068: * ByteArrayCounter.java
069: * <p/>
070: * Copyright 2000, 2001 Jcorporate Ltd.<p>
071: */
072:
073: public class ByteArrayCounter {
074:
075: private byte theArray[];
076:
077: /* Begin Test Program
078:
079: public static void main(String argv[]) throws Exception {
080: int i;
081: ByteArrayCounter counter = new ByteArrayCounter(1);
082:
083: //Test Overflow
084: for (i = 0; i < 514; i++)
085: {
086: counter.increment();
087: System.out.print(new String(counter.getBytes()));
088: }
089:
090: counter = null;
091: //Test multi-byte arrays
092: counter = new ByteArrayCounter(4);
093: for (i = 0; i < 1025; i++)
094: {
095: counter.increment();
096: System.out.print(new String(counter.getBytes()));
097: }
098:
099: }
100:
101:
102: // End Test Program */
103:
104: /**
105: * ByteArrayCounter: Initialize a counter that uses an array of bytes
106: *
107: * @param arraySize the number of bytes the counter array is supposed
108: * to take eg 4 or 8
109: */
110: public ByteArrayCounter(int arraySize) {
111: theArray = new byte[arraySize];
112: } /* ByteArrayCounter(int) */
113:
114: /**
115: * getBytes: Return a copy of the byte array.
116: *
117: * @return Return a copy of the byte array
118: */
119: public byte[] getBytes() {
120: return (new String(theArray)).getBytes();
121: } /* getBytes() */
122:
123: /**
124: * increment: Increment the value stored in the byte array
125: */
126: public synchronized void increment() {
127: int i;
128: byte carry = 0;
129: for (i = theArray.length - 1; i >= 0; i--) {
130: //Carry condition
131: if (theArray[i] == 127
132: || (theArray[i] == 126 && carry == 1)) {
133: if (i == 0) //Hit overflow condition
134: {
135: int j;
136: for (j = 0; j < theArray.length; j++) {
137: theArray[j] = 0;
138: }
139: break;
140: } else {
141: carry = 1;
142: theArray[i] = 0;
143: }
144: } else {
145: //No Carry needed
146: theArray[i]++;
147: break;
148: }
149: }
150: } /* increment() */
151:
152: } /* ByteArrayCounter */
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