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Java > Open Source Codes > com > jcorporate > expresso > core > misc > ByteArrayCounter


1 /* ====================================================================
2  * The Jcorporate Apache Style Software License, Version 1.2 05-07-2002
3  *
4  * Copyright (c) 1995-2002 Jcorporate Ltd. All rights reserved.
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19  * if any, must include the following acknowledgment:
20  * "This product includes software developed by Jcorporate Ltd.
21  * (http://www.jcorporate.com/)."
22  * Alternately, this acknowledgment may appear in the software itself,
23  * if and wherever such third-party acknowledgments normally appear.
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59  * <http://www.jcorporate.com/>.
60  *
61  * Portions of this software are based upon other open source
62  * products and are subject to their respective licenses.
63  */
64
65 package com.jcorporate.expresso.core.misc;
66
67 /**
68  * ByteArrayCounter.java
69  * <p/>
70  * Copyright 2000, 2001 Jcorporate Ltd.<p>
71  */
72
73 public class ByteArrayCounter {
74
75     private byte theArray[];
76
77     /* Begin Test Program
78
79     public static void main(String argv[]) throws Exception {
80 int i;
81 ByteArrayCounter counter = new ByteArrayCounter(1);
82
83 //Test Overflow
84 for (i = 0; i < 514; i++)
85 {
86 counter.increment();
87 System.out.print(new String(counter.getBytes()));
88 }
89
90 counter = null;
91 //Test multi-byte arrays
92 counter = new ByteArrayCounter(4);
93 for (i = 0; i < 1025; i++)
94 {
95 counter.increment();
96 System.out.print(new String(counter.getBytes()));
97 }
98
99     }
100
101
102 // End Test Program */
103
104
105     /**
106      * ByteArrayCounter: Initialize a counter that uses an array of bytes
107      *
108      * @param arraySize the number of bytes the counter array is supposed
109      * to take eg 4 or 8
110      */
111     public ByteArrayCounter(int arraySize) {
112         theArray = new byte[arraySize];
113     } /* ByteArrayCounter(int) */
114
115
116     /**
117      * getBytes: Return a copy of the byte array.
118      *
119      * @return Return a copy of the byte array
120      */
121     public byte[] getBytes() {
122         return (new String JavaDoc(theArray)).getBytes();
123     } /* getBytes() */
124
125
126     /**
127      * increment: Increment the value stored in the byte array
128      */
129     public synchronized void increment() {
130         int i;
131         byte carry = 0;
132         for (i = theArray.length - 1; i >= 0; i--) {
133 //Carry condition
134 if (theArray[i] == 127 || (theArray[i] == 126 && carry == 1)) {
135                 if (i == 0) //Hit overflow condition
136 {
137                     int j;
138                     for (j = 0; j < theArray.length; j++) {
139                         theArray[j] = 0;
140                     }
141                     break;
142                 } else {
143                     carry = 1;
144                     theArray[i] = 0;
145                 }
146             } else {
147 //No Carry needed
148 theArray[i]++;
149                 break;
150             }
151         }
152     } /* increment() */
153
154 } /* ByteArrayCounter */
155
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