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/*
* Copyright (c) 1997, 2019, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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*/
package java.util.jar;
import java.util.zip.*;
import java.io.*;
/**
* The {@code JarOutputStream} class is used to write the contents
* of a JAR file to any output stream. It extends the class
* {@code java.util.zip.ZipOutputStream} with support
* for writing an optional {@code Manifest} entry. The
* {@code Manifest} can be used to specify meta-information about
* the JAR file and its entries.
*
* @author David Connelly
* @see Manifest
* @see java.util.zip.ZipOutputStream
* @since 1.2
*/
public class JarOutputStream extends ZipOutputStream {
private static final int JAR_MAGIC = 0xCAFE;
/**
* Creates a new {@code JarOutputStream} with the specified
* {@code Manifest}. The manifest is written as the first
* entry to the output stream.
*
* @param out the actual output stream
* @param man the optional {@code Manifest}
* @throws IOException if an I/O error has occurred
*/
public JarOutputStream(OutputStream out, Manifest man) throws IOException {
super(out);
if (man == null) {
throw new NullPointerException("man");
}
ZipEntry e = new ZipEntry(JarFile.MANIFEST_NAME);
putNextEntry(e);
man.write(new BufferedOutputStream(this));
closeEntry();
}
/**
* Creates a new {@code JarOutputStream} with no manifest.
* @param out the actual output stream
* @throws IOException if an I/O error has occurred
*/
public JarOutputStream(OutputStream out) throws IOException {
super(out);
}
/**
* Begins writing a new JAR file entry and positions the stream
* to the start of the entry data. This method will also close
* any previous entry.
*
* The default compression method will be used if no compression
* method was specified for the entry. When writing a compressed
* (DEFLATED) entry, and the compressed size has not been explicitly
* set with the {@link ZipEntry#setCompressedSize(long)} method,
* then the compressed size will be set to the actual compressed
* size after deflation.
*
* The current time will be used if the entry has no set modification
* time.
*
* @param ze the ZIP/JAR entry to be written
* @throws ZipException if a ZIP error has occurred
* @throws IOException if an I/O error has occurred
*/
public void putNextEntry(ZipEntry ze) throws IOException {
if (firstEntry) {
// Make sure that extra field data for first JAR
// entry includes JAR magic number id.
byte[] edata = ze.getExtra();
if (edata == null || !hasMagic(edata)) {
if (edata == null) {
edata = new byte[4];
} else {
// Prepend magic to existing extra data
byte[] tmp = new byte[edata.length + 4];
System.arraycopy(edata, 0, tmp, 4, edata.length);
edata = tmp;
}
set16(edata, 0, JAR_MAGIC); // extra field id
set16(edata, 2, 0); // extra field size
ze.setExtra(edata);
}
firstEntry = false;
}
super.putNextEntry(ze);
}
private boolean firstEntry = true;
/*
* Returns true if specified byte array contains the
* jar magic extra field id.
*/
private static boolean hasMagic(byte[] edata) {
try {
int i = 0;
while (i < edata.length) {
if (get16(edata, i) == JAR_MAGIC) {
return true;
}
i += get16(edata, i + 2) + 4;
}
} catch (ArrayIndexOutOfBoundsException e) {
// Invalid extra field data
}
return false;
}
/*
* Fetches unsigned 16-bit value from byte array at specified offset.
* The bytes are assumed to be in Intel (little-endian) byte order.
*/
private static int get16(byte[] b, int off) {
return Byte.toUnsignedInt(b[off]) | ( Byte.toUnsignedInt(b[off+1]) << 8);
}
/*
* Sets 16-bit value at specified offset. The bytes are assumed to
* be in Intel (little-endian) byte order.
*/
private static void set16(byte[] b, int off, int value) {
b[off+0] = (byte)value;
b[off+1] = (byte)(value >> 8);
}
}