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Apache Commons Compress defines an API for working with
compression and archive formats. These include bzip2, gzip, pack200,
LZMA, XZ, Snappy, traditional Unix Compress, DEFLATE, DEFLATE64, LZ4,
Brotli, Zstandard and ar, cpio, jar, tar, zip, dump, 7z, arj.
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
*/
package org.apache.commons.compress.archivers.zip;
import java.io.Serializable;
import java.math.BigInteger;
import static org.apache.commons.compress.archivers.zip.ZipConstants.BYTE_MASK;
/**
* Utility class that represents an eight byte integer with conversion
* rules for the little endian byte order of ZIP files.
* @Immutable
*
* @since 1.2
*/
public final class ZipEightByteInteger implements Serializable {
private static final long serialVersionUID = 1L;
private static final int BYTE_1 = 1;
private static final int BYTE_1_MASK = 0xFF00;
private static final int BYTE_1_SHIFT = 8;
private static final int BYTE_2 = 2;
private static final int BYTE_2_MASK = 0xFF0000;
private static final int BYTE_2_SHIFT = 16;
private static final int BYTE_3 = 3;
private static final long BYTE_3_MASK = 0xFF000000L;
private static final int BYTE_3_SHIFT = 24;
private static final int BYTE_4 = 4;
private static final long BYTE_4_MASK = 0xFF00000000L;
private static final int BYTE_4_SHIFT = 32;
private static final int BYTE_5 = 5;
private static final long BYTE_5_MASK = 0xFF0000000000L;
private static final int BYTE_5_SHIFT = 40;
private static final int BYTE_6 = 6;
private static final long BYTE_6_MASK = 0xFF000000000000L;
private static final int BYTE_6_SHIFT = 48;
private static final int BYTE_7 = 7;
private static final long BYTE_7_MASK = 0x7F00000000000000L;
private static final int BYTE_7_SHIFT = 56;
private static final int LEFTMOST_BIT_SHIFT = 63;
private static final byte LEFTMOST_BIT = (byte) 0x80;
private final BigInteger value;
public static final ZipEightByteInteger ZERO = new ZipEightByteInteger(0);
/**
* Create instance from a number.
* @param value the long to store as a ZipEightByteInteger
*/
public ZipEightByteInteger(final long value) {
this(BigInteger.valueOf(value));
}
/**
* Create instance from a number.
* @param value the BigInteger to store as a ZipEightByteInteger
*/
public ZipEightByteInteger(final BigInteger value) {
this.value = value;
}
/**
* Create instance from bytes.
* @param bytes the bytes to store as a ZipEightByteInteger
*/
public ZipEightByteInteger (final byte[] bytes) {
this(bytes, 0);
}
/**
* Create instance from the eight bytes starting at offset.
* @param bytes the bytes to store as a ZipEightByteInteger
* @param offset the offset to start
*/
public ZipEightByteInteger (final byte[] bytes, final int offset) {
value = ZipEightByteInteger.getValue(bytes, offset);
}
/**
* Get value as eight bytes in big endian byte order.
* @return value as eight bytes in big endian order
*/
public byte[] getBytes() {
return ZipEightByteInteger.getBytes(value);
}
/**
* Get value as Java long.
* @return value as a long
*/
public long getLongValue() {
return value.longValue();
}
/**
* Get value as Java long.
* @return value as a long
*/
public BigInteger getValue() {
return value;
}
/**
* Get value as eight bytes in big endian byte order.
* @param value the value to convert
* @return value as eight bytes in big endian byte order
*/
public static byte[] getBytes(final long value) {
return getBytes(BigInteger.valueOf(value));
}
/**
* Get value as eight bytes in big endian byte order.
* @param value the value to convert
* @return value as eight bytes in big endian byte order
*/
public static byte[] getBytes(final BigInteger value) {
final byte[] result = new byte[8];
final long val = value.longValue();
result[0] = (byte) ((val & BYTE_MASK));
result[BYTE_1] = (byte) ((val & BYTE_1_MASK) >> BYTE_1_SHIFT);
result[BYTE_2] = (byte) ((val & BYTE_2_MASK) >> BYTE_2_SHIFT);
result[BYTE_3] = (byte) ((val & BYTE_3_MASK) >> BYTE_3_SHIFT);
result[BYTE_4] = (byte) ((val & BYTE_4_MASK) >> BYTE_4_SHIFT);
result[BYTE_5] = (byte) ((val & BYTE_5_MASK) >> BYTE_5_SHIFT);
result[BYTE_6] = (byte) ((val & BYTE_6_MASK) >> BYTE_6_SHIFT);
result[BYTE_7] = (byte) ((val & BYTE_7_MASK) >> BYTE_7_SHIFT);
if (value.testBit(LEFTMOST_BIT_SHIFT)) {
result[BYTE_7] |= LEFTMOST_BIT;
}
return result;
}
/**
* Helper method to get the value as a Java long from eight bytes
* starting at given array offset
* @param bytes the array of bytes
* @param offset the offset to start
* @return the corresponding Java long value
*/
public static long getLongValue(final byte[] bytes, final int offset) {
return getValue(bytes, offset).longValue();
}
/**
* Helper method to get the value as a Java BigInteger from eight
* bytes starting at given array offset
* @param bytes the array of bytes
* @param offset the offset to start
* @return the corresponding Java BigInteger value
*/
public static BigInteger getValue(final byte[] bytes, final int offset) {
long value = ((long) bytes[offset + BYTE_7] << BYTE_7_SHIFT) & BYTE_7_MASK;
value += ((long) bytes[offset + BYTE_6] << BYTE_6_SHIFT) & BYTE_6_MASK;
value += ((long) bytes[offset + BYTE_5] << BYTE_5_SHIFT) & BYTE_5_MASK;
value += ((long) bytes[offset + BYTE_4] << BYTE_4_SHIFT) & BYTE_4_MASK;
value += ((long) bytes[offset + BYTE_3] << BYTE_3_SHIFT) & BYTE_3_MASK;
value += ((long) bytes[offset + BYTE_2] << BYTE_2_SHIFT) & BYTE_2_MASK;
value += ((long) bytes[offset + BYTE_1] << BYTE_1_SHIFT) & BYTE_1_MASK;
value += ((long) bytes[offset] & BYTE_MASK);
final BigInteger val = BigInteger.valueOf(value);
return (bytes[offset + BYTE_7] & LEFTMOST_BIT) == LEFTMOST_BIT
? val.setBit(LEFTMOST_BIT_SHIFT) : val;
}
/**
* Helper method to get the value as a Java long from an eight-byte array
* @param bytes the array of bytes
* @return the corresponding Java long value
*/
public static long getLongValue(final byte[] bytes) {
return getLongValue(bytes, 0);
}
/**
* Helper method to get the value as a Java long from an eight-byte array
* @param bytes the array of bytes
* @return the corresponding Java BigInteger value
*/
public static BigInteger getValue(final byte[] bytes) {
return getValue(bytes, 0);
}
/**
* Override to make two instances with same value equal.
* @param o an object to compare
* @return true if the objects are equal
*/
@Override
public boolean equals(final Object o) {
if (o == null || !(o instanceof ZipEightByteInteger)) {
return false;
}
return value.equals(((ZipEightByteInteger) o).getValue());
}
/**
* Override to make two instances with same value equal.
* @return the hashCode of the value stored in the ZipEightByteInteger
*/
@Override
public int hashCode() {
return value.hashCode();
}
@Override
public String toString() {
return "ZipEightByteInteger value: " + value;
}
}
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