ZipEightByteInteger.java
/*
* 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 static org.apache.commons.compress.archivers.zip.ZipConstants.BYTE_MASK;
import java.io.Serializable;
import java.math.BigInteger;
/**
* 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;
public static final ZipEightByteInteger ZERO = new ZipEightByteInteger(0);
/**
* Gets 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;
}
/**
* Gets 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));
}
/**
* 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 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 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);
}
/**
* 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;
}
private final BigInteger value;
/**
* Constructs a new instance from a number.
*
* @param value the BigInteger to store as a ZipEightByteInteger
*/
public ZipEightByteInteger(final BigInteger value) {
this.value = value;
}
/**
* Constructs a new instance from bytes.
*
* @param bytes the bytes to store as a ZipEightByteInteger
*/
public ZipEightByteInteger(final byte[] bytes) {
this(bytes, 0);
}
/**
* Constructs a new 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 = getValue(bytes, offset);
}
/**
* Constructs a new instance from a number.
*
* @param value the long to store as a ZipEightByteInteger
*/
public ZipEightByteInteger(final long value) {
this(BigInteger.valueOf(value));
}
/**
* 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 instanceof ZipEightByteInteger)) {
return false;
}
return value.equals(((ZipEightByteInteger) o).getValue());
}
/**
* Gets value as eight bytes in big-endian byte order.
*
* @return value as eight bytes in big-endian order
*/
public byte[] getBytes() {
return getBytes(value);
}
/**
* Gets value as Java long.
*
* @return value as a long
*/
public long getLongValue() {
return value.longValue();
}
/**
* Gets value as Java BigInteger.
*
* @return value as a BigInteger
*/
public BigInteger getValue() {
return value;
}
/**
* Override to make two instances with same value equal.
*
* @return the hash code of the value stored in the ZipEightByteInteger
*/
@Override
public int hashCode() {
return value.hashCode();
}
@Override
public String toString() {
return "ZipEightByteInteger value: " + value;
}
}