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/*
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* Copyright 1996-2006 Sun Microsystems, Inc. All Rights Reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 only, as
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* published by the Free Software Foundation. Sun designates this
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* particular file as subject to the "Classpath" exception as provided
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* by Sun in the LICENSE file that accompanied this code.
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*
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* This code is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* version 2 for more details (a copy is included in the LICENSE file that
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* accompanied this code).
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*
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* You should have received a copy of the GNU General Public License version
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* 2 along with this work; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
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* CA 95054 USA or visit www.sun.com if you need additional information or
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* have any questions.
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*/
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package java.util.zip;
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import java.io.FilterOutputStream;
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import java.io.OutputStream;
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import java.io.InputStream;
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import java.io.IOException;
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/**
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* This class implements an output stream filter for compressing data in
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* the "deflate" compression format. It is also used as the basis for other
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* types of compression filters, such as GZIPOutputStream.
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*
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* @see Deflater
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* @author David Connelly
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*/
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public
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class DeflaterOutputStream extends FilterOutputStream {
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/**
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* Compressor for this stream.
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*/
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protected Deflater def;
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/**
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* Output buffer for writing compressed data.
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*/
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protected byte[] buf;
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/**
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* Indicates that the stream has been closed.
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*/
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private boolean closed = false;
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/**
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* Creates a new output stream with the specified compressor and
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* buffer size.
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* @param out the output stream
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* @param def the compressor ("deflater")
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* @param size the output buffer size
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* @exception IllegalArgumentException if size is <= 0
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*/
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public DeflaterOutputStream(OutputStream out, Deflater def, int size) {
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super(out);
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if (out == null || def == null) {
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throw new NullPointerException();
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} else if (size <= 0) {
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throw new IllegalArgumentException("buffer size <= 0");
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}
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this.def = def;
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buf = new byte[size];
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}
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/**
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* Creates a new output stream with the specified compressor and
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* a default buffer size.
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* @param out the output stream
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* @param def the compressor ("deflater")
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*/
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public DeflaterOutputStream(OutputStream out, Deflater def) {
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this(out, def, 512);
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}
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boolean usesDefaultDeflater = false;
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/**
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* Creates a new output stream with a default compressor and buffer size.
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* @param out the output stream
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*/
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public DeflaterOutputStream(OutputStream out) {
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this(out, new Deflater());
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usesDefaultDeflater = true;
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}
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/**
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* Writes a byte to the compressed output stream. This method will
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* block until the byte can be written.
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* @param b the byte to be written
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* @exception IOException if an I/O error has occurred
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*/
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public void write(int b) throws IOException {
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byte[] buf = new byte[1];
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buf[0] = (byte)(b & 0xff);
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write(buf, 0, 1);
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}
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/**
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* Writes an array of bytes to the compressed output stream. This
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* method will block until all the bytes are written.
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* @param b the data to be written
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* @param off the start offset of the data
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* @param len the length of the data
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* @exception IOException if an I/O error has occurred
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*/
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public void write(byte[] b, int off, int len) throws IOException {
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if (def.finished()) {
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throw new IOException("write beyond end of stream");
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}
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if ((off | len | (off + len) | (b.length - (off + len))) < 0) {
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throw new IndexOutOfBoundsException();
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} else if (len == 0) {
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return;
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}
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if (!def.finished()) {
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// Deflate no more than stride bytes at a time. This avoids
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// excess copying in deflateBytes (see Deflater.c)
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int stride = buf.length;
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for (int i = 0; i < len; i+= stride) {
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def.setInput(b, off + i, Math.min(stride, len - i));
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while (!def.needsInput()) {
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deflate();
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}
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}
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}
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}
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/**
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* Finishes writing compressed data to the output stream without closing
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* the underlying stream. Use this method when applying multiple filters
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* in succession to the same output stream.
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* @exception IOException if an I/O error has occurred
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*/
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public void finish() throws IOException {
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if (!def.finished()) {
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def.finish();
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while (!def.finished()) {
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deflate();
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}
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}
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}
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/**
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* Writes remaining compressed data to the output stream and closes the
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* underlying stream.
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* @exception IOException if an I/O error has occurred
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*/
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public void close() throws IOException {
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if (!closed) {
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finish();
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if (usesDefaultDeflater)
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def.end();
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out.close();
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closed = true;
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}
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}
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/**
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* Writes next block of compressed data to the output stream.
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* @throws IOException if an I/O error has occurred
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*/
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protected void deflate() throws IOException {
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int len = def.deflate(buf, 0, buf.length);
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if (len > 0) {
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out.write(buf, 0, len);
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}
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}
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}
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