239 lines
8.7 KiB
Java
239 lines
8.7 KiB
Java
|
/*
|
||
|
|
* Copyright (c) 1996, 2021, 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
|
||
|
|
* or visit www.oracle.com if you need additional information or have any
|
||
|
|
* questions.
|
||
|
|
*/
|
||
|
|
|
||
|
|
package java.util.zip;
|
||
|
|
|
||
|
|
import java.io.OutputStream;
|
||
|
|
import java.io.IOException;
|
||
|
|
|
||
|
|
/**
|
||
|
|
* This class implements a stream filter for writing compressed data in
|
||
|
|
* the GZIP file format.
|
||
|
|
* @author David Connelly
|
||
|
|
* @since 1.1
|
||
|
|
*
|
||
|
|
*/
|
||
|
|
public class GZIPOutputStream extends DeflaterOutputStream {
|
||
|
|
/**
|
||
|
|
* CRC-32 of uncompressed data.
|
||
|
|
*/
|
||
|
|
protected CRC32 crc = new CRC32();
|
||
|
|
|
||
|
|
/*
|
||
|
|
* GZIP header magic number.
|
||
|
|
*/
|
||
|
|
private static final int GZIP_MAGIC = 0x8b1f;
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Trailer size in bytes.
|
||
|
|
*
|
||
|
|
*/
|
||
|
|
private static final int TRAILER_SIZE = 8;
|
||
|
|
|
||
|
|
// Represents the default "unknown" value for OS header, per RFC-1952
|
||
|
|
private static final byte OS_UNKNOWN = (byte) 255;
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Creates a new output stream with the specified buffer size.
|
||
|
|
*
|
||
|
|
* <p>The new output stream instance is created as if by invoking
|
||
|
|
* the 3-argument constructor GZIPOutputStream(out, size, false).
|
||
|
|
*
|
||
|
|
* Android-note: Android limits the number of UnbufferedIO operations that can be performed, so
|
||
|
|
* consider using buffered inputs with this class. More information can be found in the
|
||
|
|
* <a href="https://developer.android.com/reference/android/os/StrictMode.ThreadPolicy.Builder#detectUnbufferedIo()">
|
||
|
|
* UnbufferedIO</a> and
|
||
|
|
* <a href="https://developer.android.com/reference/android/os/StrictMode"> StrictMode</a>
|
||
|
|
* documentation.
|
||
|
|
*
|
||
|
|
* @param out the output stream
|
||
|
|
* @param size the output buffer size
|
||
|
|
* @throws IOException If an I/O error has occurred.
|
||
|
|
* @throws IllegalArgumentException if {@code size <= 0}
|
||
|
|
*/
|
||
|
|
public GZIPOutputStream(OutputStream out, int size) throws IOException {
|
||
|
|
this(out, size, false);
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Creates a new output stream with the specified buffer size and
|
||
|
|
* flush mode.
|
||
|
|
*
|
||
|
|
* @param out the output stream
|
||
|
|
* @param size the output buffer size
|
||
|
|
* @param syncFlush
|
||
|
|
* if {@code true} invocation of the inherited
|
||
|
|
* {@link DeflaterOutputStream#flush() flush()} method of
|
||
|
|
* this instance flushes the compressor with flush mode
|
||
|
|
* {@link Deflater#SYNC_FLUSH} before flushing the output
|
||
|
|
* stream, otherwise only flushes the output stream
|
||
|
|
* @throws IOException If an I/O error has occurred.
|
||
|
|
* @throws IllegalArgumentException if {@code size <= 0}
|
||
|
|
*
|
||
|
|
* @since 1.7
|
||
|
|
*/
|
||
|
|
public GZIPOutputStream(OutputStream out, int size, boolean syncFlush)
|
||
|
|
throws IOException
|
||
|
|
{
|
||
|
|
super(out, out != null ? new Deflater(Deflater.DEFAULT_COMPRESSION, true) : null,
|
||
|
|
size,
|
||
|
|
syncFlush);
|
||
|
|
usesDefaultDeflater = true;
|
||
|
|
writeHeader();
|
||
|
|
crc.reset();
|
||
|
|
}
|
||
|
|
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Creates a new output stream with a default buffer size.
|
||
|
|
*
|
||
|
|
* <p>The new output stream instance is created as if by invoking
|
||
|
|
* the 2-argument constructor GZIPOutputStream(out, false).
|
||
|
|
*
|
||
|
|
* @param out the output stream
|
||
|
|
* @throws IOException If an I/O error has occurred.
|
||
|
|
*/
|
||
|
|
public GZIPOutputStream(OutputStream out) throws IOException {
|
||
|
|
this(out, 512, false);
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Creates a new output stream with a default buffer size and
|
||
|
|
* the specified flush mode.
|
||
|
|
*
|
||
|
|
* @param out the output stream
|
||
|
|
* @param syncFlush
|
||
|
|
* if {@code true} invocation of the inherited
|
||
|
|
* {@link DeflaterOutputStream#flush() flush()} method of
|
||
|
|
* this instance flushes the compressor with flush mode
|
||
|
|
* {@link Deflater#SYNC_FLUSH} before flushing the output
|
||
|
|
* stream, otherwise only flushes the output stream
|
||
|
|
*
|
||
|
|
* @throws IOException If an I/O error has occurred.
|
||
|
|
*
|
||
|
|
* @since 1.7
|
||
|
|
*/
|
||
|
|
public GZIPOutputStream(OutputStream out, boolean syncFlush)
|
||
|
|
throws IOException
|
||
|
|
{
|
||
|
|
this(out, 512, syncFlush);
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Writes array of bytes to the compressed output stream. This method
|
||
|
|
* will block until all the bytes are written.
|
||
|
|
* @param buf the data to be written
|
||
|
|
* @param off the start offset of the data
|
||
|
|
* @param len the length of the data
|
||
|
|
* @throws IOException If an I/O error has occurred.
|
||
|
|
*/
|
||
|
|
public synchronized void write(byte[] buf, int off, int len)
|
||
|
|
throws IOException
|
||
|
|
{
|
||
|
|
super.write(buf, off, len);
|
||
|
|
crc.update(buf, off, len);
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Finishes writing compressed data to the output stream without closing
|
||
|
|
* the underlying stream. Use this method when applying multiple filters
|
||
|
|
* in succession to the same output stream.
|
||
|
|
* @throws IOException if an I/O error has occurred
|
||
|
|
*/
|
||
|
|
public void finish() throws IOException {
|
||
|
|
if (!def.finished()) {
|
||
|
|
try {
|
||
|
|
def.finish();
|
||
|
|
while (!def.finished()) {
|
||
|
|
int len = def.deflate(buf, 0, buf.length);
|
||
|
|
if (def.finished() && len <= buf.length - TRAILER_SIZE) {
|
||
|
|
// last deflater buffer. Fit trailer at the end
|
||
|
|
writeTrailer(buf, len);
|
||
|
|
len = len + TRAILER_SIZE;
|
||
|
|
out.write(buf, 0, len);
|
||
|
|
return;
|
||
|
|
}
|
||
|
|
if (len > 0)
|
||
|
|
out.write(buf, 0, len);
|
||
|
|
}
|
||
|
|
// if we can't fit the trailer at the end of the last
|
||
|
|
// deflater buffer, we write it separately
|
||
|
|
byte[] trailer = new byte[TRAILER_SIZE];
|
||
|
|
writeTrailer(trailer, 0);
|
||
|
|
out.write(trailer);
|
||
|
|
} catch (IOException e) {
|
||
|
|
if (usesDefaultDeflater)
|
||
|
|
def.end();
|
||
|
|
throw e;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Writes GZIP member header.
|
||
|
|
*/
|
||
|
|
private void writeHeader() throws IOException {
|
||
|
|
out.write(new byte[] {
|
||
|
|
(byte) GZIP_MAGIC, // Magic number (short)
|
||
|
|
(byte)(GZIP_MAGIC >> 8), // Magic number (short)
|
||
|
|
Deflater.DEFLATED, // Compression method (CM)
|
||
|
|
0, // Flags (FLG)
|
||
|
|
0, // Modification time MTIME (int)
|
||
|
|
0, // Modification time MTIME (int)
|
||
|
|
0, // Modification time MTIME (int)
|
||
|
|
0, // Modification time MTIME (int)
|
||
|
|
0, // Extra flags (XFLG)
|
||
|
|
OS_UNKNOWN // Operating system (OS)
|
||
|
|
});
|
||
|
|
}
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Writes GZIP member trailer to a byte array, starting at a given
|
||
|
|
* offset.
|
||
|
|
*/
|
||
|
|
private void writeTrailer(byte[] buf, int offset) throws IOException {
|
||
|
|
writeInt((int)crc.getValue(), buf, offset); // CRC-32 of uncompr. data
|
||
|
|
writeInt(def.getTotalIn(), buf, offset + 4); // Number of uncompr. bytes
|
||
|
|
}
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Writes integer in Intel byte order to a byte array, starting at a
|
||
|
|
* given offset.
|
||
|
|
*/
|
||
|
|
private void writeInt(int i, byte[] buf, int offset) throws IOException {
|
||
|
|
writeShort(i & 0xffff, buf, offset);
|
||
|
|
writeShort((i >> 16) & 0xffff, buf, offset + 2);
|
||
|
|
}
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Writes short integer in Intel byte order to a byte array, starting
|
||
|
|
* at a given offset
|
||
|
|
*/
|
||
|
|
private void writeShort(int s, byte[] buf, int offset) throws IOException {
|
||
|
|
buf[offset] = (byte)(s & 0xff);
|
||
|
|
buf[offset + 1] = (byte)((s >> 8) & 0xff);
|
||
|
|
}
|
||
|
|
}
|