    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 *
    017 */
    018package org.apache.commons.compress.archivers.zip;
    019
    020import java.io.Serializable;
    021
    022import static org.apache.commons.compress.archivers.zip.ZipConstants.BYTE_MASK;
    023import static org.apache.commons.compress.archivers.zip.ZipConstants.WORD;
    024
    025/**
    026 * Utility class that represents a four byte integer with conversion
    027 * rules for the big endian byte order of ZIP files.
    028 * @Immutable
    029 */
    030public final class ZipLong implements Cloneable, Serializable {
    031    private static final long serialVersionUID = 1L;
    032
    033    //private static final int BYTE_BIT_SIZE = 8;
    034
    035    private static final int BYTE_1 = 1;
    036    private static final int BYTE_1_MASK = 0xFF00;
    037    private static final int BYTE_1_SHIFT = 8;
    038
    039    private static final int BYTE_2 = 2;
    040    private static final int BYTE_2_MASK = 0xFF0000;
    041    private static final int BYTE_2_SHIFT = 16;
    042
    043    private static final int BYTE_3 = 3;
    044    private static final long BYTE_3_MASK = 0xFF000000L;
    045    private static final int BYTE_3_SHIFT = 24;
    046
    047    private final long value;
    048
    049    /** Central File Header Signature */
    050    public static final ZipLong CFH_SIG = new ZipLong(0X02014B50L);
    051
    052    /** Local File Header Signature */
    053    public static final ZipLong LFH_SIG = new ZipLong(0X04034B50L);
    054
    055    /**
    056     * Data Descriptor signature.
    057     *
    058     * <p>Actually, PKWARE uses this as marker for split/spanned
    059     * archives and other archivers have started to use it as Data
    060     * Descriptor signature (as well).</p>
    061     * @since 1.1
    062     */
    063    public static final ZipLong DD_SIG = new ZipLong(0X08074B50L);
    064
    065    /**
    066     * Value stored in size and similar fields if ZIP64 extensions are
    067     * used.
    068     * @since 1.3
    069     */
    070    static final ZipLong ZIP64_MAGIC = new ZipLong(ZipConstants.ZIP64_MAGIC);
    071
    072    /**
    073     * Marks ZIP archives that were supposed to be split or spanned
    074     * but only needed a single segment in then end (so are actually
    075     * neither split nor spanned).
    076     *
    077     * <p>This is the "PK00" prefix found in some archives.</p>
    078     * @since 1.5
    079     */
    080    public static final ZipLong SINGLE_SEGMENT_SPLIT_MARKER =
    081        new ZipLong(0X30304B50L);
    082
    083    /**
    084     * Archive extra data record signature.
    085     * @since 1.5
    086     */
    087    public static final ZipLong AED_SIG = new ZipLong(0X08064B50L);
    088
    089    /**
    090     * Create instance from a number.
    091     * @param value the long to store as a ZipLong
    092     */
    093    public ZipLong(final long value) {
    094        this.value = value;
    095    }
    096
    097    /**
    098     * Create instance from bytes.
    099     * @param bytes the bytes to store as a ZipLong
    100     */
    101    public ZipLong (final byte[] bytes) {
    102        this(bytes, 0);
    103    }
    104
    105    /**
    106     * Create instance from the four bytes starting at offset.
    107     * @param bytes the bytes to store as a ZipLong
    108     * @param offset the offset to start
    109     */
    110    public ZipLong (final byte[] bytes, final int offset) {
    111        value = ZipLong.getValue(bytes, offset);
    112    }
    113
    114    /**
    115     * Get value as four bytes in big endian byte order.
    116     * @return value as four bytes in big endian order
    117     */
    118    public byte[] getBytes() {
    119        return ZipLong.getBytes(value);
    120    }
    121
    122    /**
    123     * Get value as Java long.
    124     * @return value as a long
    125     */
    126    public long getValue() {
    127        return value;
    128    }
    129
    130    /**
    131     * Get value as four bytes in big endian byte order.
    132     * @param value the value to convert
    133     * @return value as four bytes in big endian byte order
    134     */
    135    public static byte[] getBytes(final long value) {
    136        final byte[] result = new byte[WORD];
    137        putLong(value, result, 0);
    138        return result;
    139    }
    140
    141    /**
    142     * put the value as four bytes in big endian byte order.
    143     * @param value the Java long to convert to bytes
    144     * @param buf the output buffer
    145     * @param  offset
    146     *         The offset within the output buffer of the first byte to be written.
    147     *         must be non-negative and no larger than <tt>buf.length-4</tt>
    148     */
    149
    150    public static void putLong(final long value, final byte[] buf, int offset) {
    151        buf[offset++] = (byte) ((value & BYTE_MASK));
    152        buf[offset++] = (byte) ((value & BYTE_1_MASK) >> BYTE_1_SHIFT);
    153        buf[offset++] = (byte) ((value & BYTE_2_MASK) >> BYTE_2_SHIFT);
    154        buf[offset] = (byte) ((value & BYTE_3_MASK) >> BYTE_3_SHIFT);
    155    }
    156
    157    public void putLong(final byte[] buf, final int offset) {
    158        putLong(value, buf, offset);
    159    }
    160
    161    /**
    162     * Helper method to get the value as a Java long from four bytes starting at given array offset
    163     * @param bytes the array of bytes
    164     * @param offset the offset to start
    165     * @return the corresponding Java long value
    166     */
    167    public static long getValue(final byte[] bytes, final int offset) {
    168        long value = (bytes[offset + BYTE_3] << BYTE_3_SHIFT) & BYTE_3_MASK;
    169        value += (bytes[offset + BYTE_2] << BYTE_2_SHIFT) & BYTE_2_MASK;
    170        value += (bytes[offset + BYTE_1] << BYTE_1_SHIFT) & BYTE_1_MASK;
    171        value += (bytes[offset] & BYTE_MASK);
    172        return value;
    173    }
    174
    175    /**
    176     * Helper method to get the value as a Java long from a four-byte array
    177     * @param bytes the array of bytes
    178     * @return the corresponding Java long value
    179     */
    180    public static long getValue(final byte[] bytes) {
    181        return getValue(bytes, 0);
    182    }
    183
    184    /**
    185     * Override to make two instances with same value equal.
    186     * @param o an object to compare
    187     * @return true if the objects are equal
    188     */
    189    @Override
    190    public boolean equals(final Object o) {
    191        if (o == null || !(o instanceof ZipLong)) {
    192            return false;
    193        }
    194        return value == ((ZipLong) o).getValue();
    195    }
    196
    197    /**
    198     * Override to make two instances with same value equal.
    199     * @return the value stored in the ZipLong
    200     */
    201    @Override
    202    public int hashCode() {
    203        return (int) value;
    204    }
    205
    206    @Override
    207    public Object clone() {
    208        try {
    209            return super.clone();
    210        } catch (final CloneNotSupportedException cnfe) {
    211            // impossible
    212            throw new RuntimeException(cnfe); //NOSONAR
    213        }
    214    }
    215
    216    @Override
    217    public String toString() {
    218        return "ZipLong value: " + value;
    219    }
    220}