/*
* Copyright (c) 2006, 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.IOException;
import java.io.OutputStream;
/**
* Implements an output stream filter for uncompressing data stored in the
* "deflate" compression format.
*
* @since 1.6
* @author David R Tribble (david@tribble.com)
*
* @see InflaterInputStream
* @see DeflaterInputStream
* @see DeflaterOutputStream
*/
public class InflaterOutputStream extends FilterOutputStream {
/** Decompressor for this stream. */
protected final Inflater inf;
/** Output buffer for writing uncompressed data. */
protected final byte[] buf;
/** Temporary write buffer. */
private final byte[] wbuf = new byte[1];
/** Default decompressor is used. */
private boolean usesDefaultInflater = false;
/** true iff {@link #close()} has been called. */
private boolean closed = false;
/**
* Checks to make sure that this stream has not been closed.
*/
private void ensureOpen() throws IOException {
if (closed) {
throw new IOException("Stream closed");
}
}
/**
* Creates a new output stream with a default decompressor and buffer
* size.
*
* @param out output stream to write the uncompressed data to
* @throws NullPointerException if {@code out} is null
*/
public InflaterOutputStream(OutputStream out) {
this(out, new Inflater());
usesDefaultInflater = true;
}
/**
* Creates a new output stream with the specified decompressor and a
* default buffer size.
*
* @param out output stream to write the uncompressed data to
* @param infl decompressor ("inflater") for this stream
* @throws NullPointerException if {@code out} or {@code infl} is null
*/
public InflaterOutputStream(OutputStream out, Inflater infl) {
this(out, infl, 512);
}
/**
* Creates a new output stream with the specified decompressor and
* buffer size.
*
* @param out output stream to write the uncompressed data to
* @param infl decompressor ("inflater") for this stream
* @param bufLen decompression buffer size
* @throws IllegalArgumentException if {@code bufLen} is <= 0
* @throws NullPointerException if {@code out} or {@code infl} is null
*/
public InflaterOutputStream(OutputStream out, Inflater infl, int bufLen) {
super(out);
// Sanity checks
if (out == null)
throw new NullPointerException("Null output");
if (infl == null)
throw new NullPointerException("Null inflater");
if (bufLen <= 0)
throw new IllegalArgumentException("Buffer size < 1");
// Initialize
inf = infl;
buf = new byte[bufLen];
}
/**
* Writes any remaining uncompressed data to the output stream and closes
* the underlying output stream.
*
* @throws IOException if an I/O error occurs
*/
public void close() throws IOException {
if (!closed) {
// Complete the uncompressed output
try {
finish();
} finally {
out.close();
closed = true;
}
}
}
/**
* Flushes this output stream, forcing any pending buffered output bytes to be
* written.
*
* @throws IOException if an I/O error occurs or this stream is already
* closed
*/
public void flush() throws IOException {
ensureOpen();
// Finish decompressing and writing pending output data
if (!inf.finished()) {
try {
while (!inf.finished() && !inf.needsInput()) {
int n;
// Decompress pending output data
n = inf.inflate(buf, 0, buf.length);
if (n < 1) {
break;
}
// Write the uncompressed output data block
out.write(buf, 0, n);
}
super.flush();
} catch (DataFormatException ex) {
// Improperly formatted compressed (ZIP) data
String msg = ex.getMessage();
if (msg == null) {
msg = "Invalid ZLIB data format";
}
throw new ZipException(msg);
}
}
}
/**
* Finishes writing uncompressed 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 occurs or this stream is already
* closed
*/
public void finish() throws IOException {
ensureOpen();
// Finish decompressing and writing pending output data
flush();
if (usesDefaultInflater) {
inf.end();
}
}
/**
* Writes a byte to the uncompressed output stream.
*
* @param b a single byte of compressed data to decompress and write to
* the output stream
* @throws IOException if an I/O error occurs or this stream is already
* closed
* @throws ZipException if a compression (ZIP) format error occurs
*/
public void write(int b) throws IOException {
// Write a single byte of data
wbuf[0] = (byte) b;
write(wbuf, 0, 1);
}
/**
* Writes an array of bytes to the uncompressed output stream.
*
* @param b buffer containing compressed data to decompress and write to
* the output stream
* @param off starting offset of the compressed data within {@code b}
* @param len number of bytes to decompress from {@code b}
* @throws IndexOutOfBoundsException if {@code off} < 0, or if
* {@code len} < 0, or if {@code len} > {@code b.length - off}
* @throws IOException if an I/O error occurs or this stream is already
* closed
* @throws NullPointerException if {@code b} is null
* @throws ZipException if a compression (ZIP) format error occurs
*/
public void write(byte[] b, int off, int len) throws IOException {
// Sanity checks
ensureOpen();
if (b == null) {
throw new NullPointerException("Null buffer for read");
} else if (off < 0 || len < 0 || len > b.length - off) {
throw new IndexOutOfBoundsException();
} else if (len == 0) {
return;
}
// Write uncompressed data to the output stream
try {
for (;;) {
int n;
// Fill the decompressor buffer with output data
if (inf.needsInput()) {
int part;
if (len < 1) {
break;
}
part = (len < 512 ? len : 512);
inf.setInput(b, off, part);
off += part;
len -= part;
}
// Decompress and write blocks of output data
do {
n = inf.inflate(buf, 0, buf.length);
if (n > 0) {
out.write(buf, 0, n);
}
} while (n > 0);
// Check the decompressor
if (inf.finished()) {
break;
}
if (inf.needsDictionary()) {
throw new ZipException("ZLIB dictionary missing");
}
}
} catch (DataFormatException ex) {
// Improperly formatted compressed (ZIP) data
String msg = ex.getMessage();
if (msg == null) {
msg = "Invalid ZLIB data format";
}
throw new ZipException(msg);
}
}
}