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Java > Open Source Codes > org > apache > tools > zip > ZipShort


1 /*
2  * Licensed to the Apache Software Foundation (ASF) under one or more
3  * contributor license agreements. See the NOTICE file distributed with
4  * this work for additional information regarding copyright ownership.
5  * The ASF licenses this file to You under the Apache License, Version 2.0
6  * (the "License"); you may not use this file except in compliance with
7  * the License. You may obtain a copy of the License at
8  *
9  * http://www.apache.org/licenses/LICENSE-2.0
10  *
11  * Unless required by applicable law or agreed to in writing, software
12  * distributed under the License is distributed on an "AS IS" BASIS,
13  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14  * See the License for the specific language governing permissions and
15  * limitations under the License.
16  *
17  */
18
19 package org.apache.tools.zip;
20
21 /**
22  * Utility class that represents a two byte integer with conversion
23  * rules for the big endian byte order of ZIP files.
24  *
25  */
26 public final class ZipShort implements Cloneable JavaDoc {
27
28     private int value;
29
30     /**
31      * Create instance from a number.
32      * @param value the int to store as a ZipShort
33      * @since 1.1
34      */
35     public ZipShort (int value) {
36         this.value = value;
37     }
38
39     /**
40      * Create instance from bytes.
41      * @param bytes the bytes to store as a ZipShort
42      * @since 1.1
43      */
44     public ZipShort (byte[] bytes) {
45         this(bytes, 0);
46     }
47
48     /**
49      * Create instance from the two bytes starting at offset.
50      * @param bytes the bytes to store as a ZipShort
51      * @param offset the offset to start
52      * @since 1.1
53      */
54     public ZipShort (byte[] bytes, int offset) {
55         value = ZipShort.getValue(bytes, offset);
56     }
57
58     /**
59      * Get value as two bytes in big endian byte order.
60      * @return the value as a a two byte array in big endian byte order
61      * @since 1.1
62      */
63     public byte[] getBytes() {
64         byte[] result = new byte[2];
65         result[0] = (byte) (value & 0xFF);
66         result[1] = (byte) ((value & 0xFF00) >> 8);
67         return result;
68     }
69
70     /**
71      * Get value as Java int.
72      * @return value as a Java int
73      * @since 1.1
74      */
75     public int getValue() {
76         return value;
77     }
78
79     /**
80      * Get value as two bytes in big endian byte order.
81      * @param value the Java int to convert to bytes
82      * @return the converted int as a byte array in big endian byte order
83      */
84     public static byte[] getBytes(int value) {
85         byte[] result = new byte[2];
86         result[0] = (byte) (value & 0xFF);
87         result[1] = (byte) ((value & 0xFF00) >> 8);
88         return result;
89     }
90
91     /**
92      * Helper method to get the value as a java int from two bytes starting at given array offset
93      * @param bytes the array of bytes
94      * @param offset the offset to start
95      * @return the correspondanding java int value
96      */
97     public static int getValue(byte[] bytes, int offset) {
98         int value = (bytes[offset + 1] << 8) & 0xFF00;
99         value += (bytes[offset] & 0xFF);
100         return value;
101     }
102
103     /**
104      * Helper method to get the value as a java int from a two-byte array
105      * @param bytes the array of bytes
106      * @return the correspondanding java int value
107      */
108     public static int getValue(byte[] bytes) {
109         return getValue(bytes, 0);
110     }
111
112     /**
113      * Override to make two instances with same value equal.
114      * @param o an object to compare
115      * @return true if the objects are equal
116      * @since 1.1
117      */
118     public boolean equals(Object JavaDoc o) {
119         if (o == null || !(o instanceof ZipShort)) {
120             return false;
121         }
122         return value == ((ZipShort) o).getValue();
123     }
124
125     /**
126      * Override to make two instances with same value equal.
127      * @return the value stored in the ZipShort
128      * @since 1.1
129      */
130     public int hashCode() {
131         return value;
132     }
133 }
134
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