org.apache.tools.zip.ZipLong Maven / Gradle / Ivy
/*
* 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.tools.zip;
import static org.apache.tools.zip.ZipConstants.BYTE_MASK;
import static org.apache.tools.zip.ZipConstants.WORD;
/**
* Utility class that represents a four byte integer with conversion
* rules for the big endian byte order of ZIP files.
*
*/
public final class ZipLong implements Cloneable {
//private static final int BYTE_BIT_SIZE = 8;
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 final long value;
/** Central File Header Signature */
public static final ZipLong CFH_SIG = new ZipLong(0X02014B50L);
/** Local File Header Signature */
public static final ZipLong LFH_SIG = new ZipLong(0X04034B50L);
/**
* Data Descriptor signature
*/
public static final ZipLong DD_SIG = new ZipLong(0X08074B50L);
/**
* Value stored in size and similar fields if ZIP64 extensions are
* used.
*/
static final ZipLong ZIP64_MAGIC = new ZipLong(ZipConstants.ZIP64_MAGIC);
/**
* Create instance from a number.
* @param value the long to store as a ZipLong
* @since 1.1
*/
public ZipLong(long value) {
this.value = value;
}
/**
* Create instance from bytes.
* @param bytes the bytes to store as a ZipLong
* @since 1.1
*/
public ZipLong (byte[] bytes) {
this(bytes, 0);
}
/**
* Create instance from the four bytes starting at offset.
* @param bytes the bytes to store as a ZipLong
* @param offset the offset to start
* @since 1.1
*/
public ZipLong (byte[] bytes, int offset) {
value = ZipLong.getValue(bytes, offset);
}
/**
* Get value as four bytes in big endian byte order.
* @since 1.1
* @return value as four bytes in big endian order
*/
public byte[] getBytes() {
return ZipLong.getBytes(value);
}
/**
* Get value as Java long.
* @since 1.1
* @return value as a long
*/
public long getValue() {
return value;
}
/**
* Get value as four bytes in big endian byte order.
* @param value the value to convert
* @return value as four bytes in big endian byte order
*/
public static byte[] getBytes(long value) {
byte[] result = new byte[WORD];
putLong(value, result, 0);
return result;
}
/**
* put the value as four bytes in big endian byte order.
* @param value the Java long to convert to bytes
* @param buf the output buffer
* @param offset
* The offset within the output buffer of the first byte to be written.
* must be non-negative and no larger than buf.length-4
*/
public static void putLong(long value, byte[] buf, int offset) {
buf[offset++] = (byte) ((value & BYTE_MASK));
buf[offset++] = (byte) ((value & BYTE_1_MASK) >> BYTE_1_SHIFT);
buf[offset++] = (byte) ((value & BYTE_2_MASK) >> BYTE_2_SHIFT);
buf[offset] = (byte) ((value & BYTE_3_MASK) >> BYTE_3_SHIFT);
}
public void putLong(byte[] buf, int offset) {
putLong(value, buf, offset);
}
/**
* Helper method to get the value as a Java long from four 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 getValue(byte[] bytes, int offset) {
long value = (bytes[offset + BYTE_3] << BYTE_3_SHIFT) & BYTE_3_MASK;
value += (bytes[offset + BYTE_2] << BYTE_2_SHIFT) & BYTE_2_MASK;
value += (bytes[offset + BYTE_1] << BYTE_1_SHIFT) & BYTE_1_MASK;
value += (bytes[offset] & BYTE_MASK);
return value;
}
/**
* Helper method to get the value as a Java long from a four-byte array
* @param bytes the array of bytes
* @return the corresponding Java long value
*/
public static long getValue(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
* @since 1.1
*/
@Override
public boolean equals(Object o) {
if (o == null || !(o instanceof ZipLong)) {
return false;
}
return value == ((ZipLong) o).getValue();
}
/**
* Override to make two instances with same value equal.
* @return the value stored in the ZipLong
* @since 1.1
*/
@Override
public int hashCode() {
return (int) value;
}
@Override
public Object clone() {
try {
return super.clone();
} catch (CloneNotSupportedException cnfe) {
// impossible
throw new RuntimeException(cnfe);
}
}
@Override
public String toString() {
return "ZipLong value: " + value;
}
}