forked from openjdk/jdk17u-dev
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DeflaterOutputStream.java
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/
DeflaterOutputStream.java
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/*
* 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.FilterOutputStream;
import java.io.OutputStream;
import java.io.InputStream;
import java.io.IOException;
/**
* This class implements an output stream filter for compressing data in
* the "deflate" compression format. It is also used as the basis for other
* types of compression filters, such as GZIPOutputStream.
*
* @see Deflater
* @author David Connelly
* @since 1.1
*/
public class DeflaterOutputStream extends FilterOutputStream {
/**
* Compressor for this stream.
*/
protected Deflater def;
/**
* Output buffer for writing compressed data.
*/
protected byte[] buf;
/**
* Indicates that the stream has been closed.
*/
private boolean closed = false;
private final boolean syncFlush;
/**
* Creates a new output stream with the specified compressor,
* buffer size and flush mode.
*
* @param out the output stream
* @param def the compressor ("deflater")
* @param size the output buffer size
* @param syncFlush
* if {@code true} the {@link #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 IllegalArgumentException if {@code size <= 0}
*
* @since 1.7
*/
public DeflaterOutputStream(OutputStream out,
Deflater def,
int size,
boolean syncFlush) {
super(out);
if (out == null || def == null) {
throw new NullPointerException();
} else if (size <= 0) {
throw new IllegalArgumentException("buffer size <= 0");
}
this.def = def;
this.buf = new byte[size];
this.syncFlush = syncFlush;
}
/**
* Creates a new output stream with the specified compressor and
* buffer size.
*
* <p>The new output stream instance is created as if by invoking
* the 4-argument constructor DeflaterOutputStream(out, def, size, false).
*
* @param out the output stream
* @param def the compressor ("deflater")
* @param size the output buffer size
* @throws IllegalArgumentException if {@code size <= 0}
*/
public DeflaterOutputStream(OutputStream out, Deflater def, int size) {
this(out, def, size, false);
}
/**
* Creates a new output stream with the specified compressor, flush
* mode and a default buffer size.
*
* @param out the output stream
* @param def the compressor ("deflater")
* @param syncFlush
* if {@code true} the {@link #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
*
* @since 1.7
*/
public DeflaterOutputStream(OutputStream out,
Deflater def,
boolean syncFlush) {
this(out, def, 512, syncFlush);
}
/**
* Creates a new output stream with the specified compressor and
* a default buffer size.
*
* <p>The new output stream instance is created as if by invoking
* the 3-argument constructor DeflaterOutputStream(out, def, false).
*
* @param out the output stream
* @param def the compressor ("deflater")
*/
public DeflaterOutputStream(OutputStream out, Deflater def) {
this(out, def, 512, false);
}
boolean usesDefaultDeflater = false;
/**
* Creates a new output stream with a default compressor, a default
* buffer size and the specified flush mode.
*
* @param out the output stream
* @param syncFlush
* if {@code true} the {@link #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
*
* @since 1.7
*/
public DeflaterOutputStream(OutputStream out, boolean syncFlush) {
this(out, out != null ? new Deflater() : null, 512, syncFlush);
usesDefaultDeflater = true;
}
/**
* Creates a new output stream with a default compressor and buffer size.
*
* <p>The new output stream instance is created as if by invoking
* the 2-argument constructor DeflaterOutputStream(out, false).
*
* @param out the output stream
*/
public DeflaterOutputStream(OutputStream out) {
this(out, false);
usesDefaultDeflater = true;
}
/**
* Writes a byte to the compressed output stream. This method will
* block until the byte can be written.
* @param b the byte to be written
* @throws IOException if an I/O error has occurred
*/
public void write(int b) throws IOException {
byte[] buf = new byte[1];
buf[0] = (byte)(b & 0xff);
write(buf, 0, 1);
}
/**
* Writes an array of bytes to the compressed output stream. This
* method will block until all the bytes are written.
* @param b 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 void write(byte[] b, int off, int len) throws IOException {
if (def.finished()) {
throw new IOException("write beyond end of stream");
}
if ((off | len | (off + len) | (b.length - (off + len))) < 0) {
throw new IndexOutOfBoundsException();
} else if (len == 0) {
return;
}
if (!def.finished()) {
def.setInput(b, off, len);
while (!def.needsInput()) {
deflate();
}
}
}
/**
* 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()) {
def.finish();
while (!def.finished()) {
deflate();
}
}
}
/**
* Writes remaining compressed data to the output stream and closes the
* underlying stream.
* @throws IOException if an I/O error has occurred
*/
public void close() throws IOException {
if (!closed) {
try {
finish();
} finally {
if (usesDefaultDeflater)
def.end();
}
out.close();
closed = true;
}
}
/**
* Writes next block of compressed data to the output stream.
* @throws IOException if an I/O error has occurred
*/
protected void deflate() throws IOException {
int len = def.deflate(buf, 0, buf.length);
if (len > 0) {
out.write(buf, 0, len);
}
}
/**
* Flushes the compressed output stream.
*
* If {@link #DeflaterOutputStream(OutputStream, Deflater, int, boolean)
* syncFlush} is {@code true} when this compressed output stream is
* constructed, this method first flushes the underlying {@code compressor}
* with the flush mode {@link Deflater#SYNC_FLUSH} to force
* all pending data to be flushed out to the output stream and then
* flushes the output stream. Otherwise this method only flushes the
* output stream without flushing the {@code compressor}.
*
* @throws IOException if an I/O error has occurred
*
* @since 1.7
*/
public void flush() throws IOException {
if (syncFlush && !def.finished()) {
int len = 0;
while ((len = def.deflate(buf, 0, buf.length, Deflater.SYNC_FLUSH)) > 0)
{
out.write(buf, 0, len);
if (len < buf.length)
break;
}
}
out.flush();
}
}