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 java.io.Serializable;
import java.math.BigInteger;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;
/**
* 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 {
/**
* The number of bytes used to represent an instance in binary form.
*/
static final int BYTES = 8;
private static final long serialVersionUID = 1L;
/**
* Constant for a value of zero.
*/
public static final ZipEightByteInteger ZERO = new ZipEightByteInteger(0);
private static final BigInteger HIGHEST_BIT = BigInteger.ONE.shiftLeft(63);
/**
* 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) {
return getBytes(value.longValue());
}
/**
* 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 ByteBuffer.allocate(BYTES).order(ByteOrder.LITTLE_ENDIAN).putLong(value).array();
}
/**
* Gets 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);
}
/**
* Gets 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 ByteBuffer.wrap(bytes).order(ByteOrder.LITTLE_ENDIAN).getLong(offset);
}
/**
* Gets 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);
}
/**
* Gets 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) {
return toUnsignedBigInteger(getLongValue(bytes, offset));
}
/**
* package private for tests only.
*/
static BigInteger toUnsignedBigInteger(final long value) {
if (value >= 0L) {
return BigInteger.valueOf(value);
}
return BigInteger.valueOf(value & Long.MAX_VALUE).add(HIGHEST_BIT);
}
/**
* The value is treated as unsigned.
*/
private final long 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.longValue();
}
/**
* 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) {
this.value = getLongValue(bytes, offset);
}
/**
* Constructs a new instance from a number.
*
* @param value the long to store as a ZipEightByteInteger.
*/
public ZipEightByteInteger(final long value) {
this.value = 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 == ((ZipEightByteInteger) o).value;
}
/**
* 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;
}
/**
* Gets value as Java BigInteger.
*
* @return value as a BigInteger.
*/
public BigInteger getValue() {
return toUnsignedBigInteger(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 Long.hashCode(value);
}
@Override
public String toString() {
return Long.toUnsignedString(value);
}
}