/*
* Copyright (c) 1996, 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
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*/
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
*/
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;
/**
* Creates a new output stream with the specified compressor and
* buffer size.
* @param out the output stream
* @param def the compressor ("deflater")
* @param size the output buffer size
* @exception IllegalArgumentException if size is <= 0
*/
public DeflaterOutputStream(OutputStream out, Deflater def, int size) {
super(out);
if (out == null || def == null) {
throw new NullPointerException();
} else if (size <= 0) {
throw new IllegalArgumentException("buffer size <= 0");
}
this.def = def;
buf = new byte[size];
}
/**
* Creates a new output stream with the specified compressor and
* a default buffer size.
* @param out the output stream
* @param def the compressor ("deflater")
*/
public DeflaterOutputStream(OutputStream out, Deflater def) {
this(out, def, 512);
}
boolean usesDefaultDeflater = false;
/**
* Creates a new output stream with a default compressor and buffer size.
* @param out the output stream
*/
public DeflaterOutputStream(OutputStream out) {
this(out, new Deflater());
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
* @exception 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
* @exception 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()) {
// Deflate no more than stride bytes at a time. This avoids
// excess copying in deflateBytes (see Deflater.c)
int stride = buf.length;
for (int i = 0; i < len; i+= stride) {
def.setInput(b, off + i, Math.min(stride, len - i));
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.
* @exception 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.
* @exception IOException if an I/O error has occurred
*/
public void close() throws IOException {
if (!closed) {
finish();
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);
}
}
}