001/*
002 *  Licensed to the Apache Software Foundation (ASF) under one or more
003 *  contributor license agreements.  See the NOTICE file distributed with
004 *  this work for additional information regarding copyright ownership.
005 *  The ASF licenses this file to You under the Apache License, Version 2.0
006 *  (the "License"); you may not use this file except in compliance with
007 *  the License.  You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 *  Unless required by applicable law or agreed to in writing, software
012 *  distributed under the License is distributed on an "AS IS" BASIS,
013 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 *  See the License for the specific language governing permissions and
015 *  limitations under the License.
016 */
017package org.apache.commons.compress.archivers.zip;
018
019import java.io.Serializable;
020
021import org.apache.commons.compress.utils.ByteUtils;
022
023/**
024 * Utility class that represents a two byte integer with conversion rules for the little-endian byte order of ZIP files.
025 *
026 * @Immutable
027 */
028public final class ZipShort implements Cloneable, Serializable {
029    /**
030     * ZipShort with a value of 0.
031     *
032     * @since 1.14
033     */
034    public static final ZipShort ZERO = new ZipShort(0);
035
036    private static final long serialVersionUID = 1L;
037
038    /**
039     * Gets value as two bytes in big-endian byte order.
040     *
041     * @param value the Java int to convert to bytes
042     * @return the converted int as a byte array in big-endian byte order
043     */
044    public static byte[] getBytes(final int value) {
045        final byte[] result = new byte[2];
046        putShort(value, result, 0);
047        return result;
048    }
049
050    /**
051     * Helper method to get the value as a Java int from a two-byte array
052     *
053     * @param bytes the array of bytes
054     * @return the corresponding Java int value
055     */
056    public static int getValue(final byte[] bytes) {
057        return getValue(bytes, 0);
058    }
059
060    /**
061     * Helper method to get the value as a Java int from two bytes starting at given array offset
062     *
063     * @param bytes  the array of bytes
064     * @param offset the offset to start
065     * @return the corresponding Java int value
066     */
067    public static int getValue(final byte[] bytes, final int offset) {
068        return (int) ByteUtils.fromLittleEndian(bytes, offset, 2);
069    }
070
071    /**
072     * put the value as two bytes in big-endian byte order.
073     *
074     * @param value  the Java int to convert to bytes
075     * @param buf    the output buffer
076     * @param offset The offset within the output buffer of the first byte to be written. must be non-negative and no larger than {@code buf.length-2}
077     */
078    public static void putShort(final int value, final byte[] buf, final int offset) {
079        ByteUtils.toLittleEndian(buf, value, offset, 2);
080    }
081
082    private final int value;
083
084    /**
085     * Constructs a new instance from bytes.
086     *
087     * @param bytes the bytes to store as a ZipShort
088     */
089    public ZipShort(final byte[] bytes) {
090        this(bytes, 0);
091    }
092
093    /**
094     * Constructs a new instance from the two bytes starting at offset.
095     *
096     * @param bytes  the bytes to store as a ZipShort
097     * @param offset the offset to start
098     */
099    public ZipShort(final byte[] bytes, final int offset) {
100        value = getValue(bytes, offset);
101    }
102
103    /**
104     * Constructs a new instance from a number.
105     *
106     * @param value the int to store as a ZipShort
107     */
108    public ZipShort(final int value) {
109        this.value = value;
110    }
111
112    @Override
113    public Object clone() {
114        try {
115            return super.clone();
116        } catch (final CloneNotSupportedException cnfe) {
117            // impossible
118            throw new UnsupportedOperationException(cnfe); // NOSONAR
119        }
120    }
121
122    /**
123     * Override to make two instances with same value equal.
124     *
125     * @param o an object to compare
126     * @return true if the objects are equal
127     */
128    @Override
129    public boolean equals(final Object o) {
130        if (!(o instanceof ZipShort)) {
131            return false;
132        }
133        return value == ((ZipShort) o).getValue();
134    }
135
136    /**
137     * Gets value as two bytes in big-endian byte order.
138     *
139     * @return the value as a two byte array in big-endian byte order
140     */
141    public byte[] getBytes() {
142        final byte[] result = new byte[2];
143        ByteUtils.toLittleEndian(result, value, 0, 2);
144        return result;
145    }
146
147    /**
148     * Gets value as Java int.
149     *
150     * @return value as a Java int
151     */
152    public int getValue() {
153        return value;
154    }
155
156    /**
157     * Override to make two instances with same value equal.
158     *
159     * @return the value stored in the ZipShort
160     */
161    @Override
162    public int hashCode() {
163        return value;
164    }
165
166    @Override
167    public String toString() {
168        return "ZipShort value: " + value;
169    }
170}