001 /*
002 * Copyright 2006 Sun Microsystems, Inc. All Rights Reserved.
003 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
004 *
005 * This code is free software; you can redistribute it and/or modify it
006 * under the terms of the GNU General Public License version 2 only, as
007 * published by the Free Software Foundation. Sun designates this
008 * particular file as subject to the "Classpath" exception as provided
009 * by Sun in the LICENSE file that accompanied this code.
010 *
011 * This code is distributed in the hope that it will be useful, but WITHOUT
012 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
013 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
014 * version 2 for more details (a copy is included in the LICENSE file that
015 * accompanied this code).
016 *
017 * You should have received a copy of the GNU General Public License version
018 * 2 along with this work; if not, write to the Free Software Foundation,
019 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
020 *
021 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
022 * CA 95054 USA or visit www.sun.com if you need additional information or
023 * have any questions.
024 */
025
026 package java.util.zip;
027
028 import java.io.FilterOutputStream;
029 import java.io.IOException;
030 import java.io.OutputStream;
031
032 /**
033 * Implements an output stream filter for uncompressing data stored in the
034 * "deflate" compression format.
035 *
036 * @version 1.7
037 * @since 1.6
038 * @author David R Tribble (david@tribble.com)
039 *
040 * @see InflaterInputStream
041 * @see DeflaterInputStream
042 * @see DeflaterOutputStream
043 */
044
045 public class InflaterOutputStream extends FilterOutputStream {
046 /** Decompressor for this stream. */
047 protected final Inflater inf;
048
049 /** Output buffer for writing uncompressed data. */
050 protected final byte[] buf;
051
052 /** Temporary write buffer. */
053 private final byte[] wbuf = new byte[1];
054
055 /** Default decompressor is used. */
056 private boolean usesDefaultInflater = false;
057
058 /** true iff {@link #close()} has been called. */
059 private boolean closed = false;
060
061 /**
062 * Checks to make sure that this stream has not been closed.
063 */
064 private void ensureOpen() throws IOException {
065 if (closed) {
066 throw new IOException("Stream closed");
067 }
068 }
069
070 /**
071 * Creates a new output stream with a default decompressor and buffer
072 * size.
073 *
074 * @param out output stream to write the uncompressed data to
075 * @throws NullPointerException if {@code out} is null
076 */
077 public InflaterOutputStream(OutputStream out) {
078 this (out, new Inflater());
079 usesDefaultInflater = true;
080 }
081
082 /**
083 * Creates a new output stream with the specified decompressor and a
084 * default buffer size.
085 *
086 * @param out output stream to write the uncompressed data to
087 * @param infl decompressor ("inflater") for this stream
088 * @throws NullPointerException if {@code out} or {@code infl} is null
089 */
090 public InflaterOutputStream(OutputStream out, Inflater infl) {
091 this (out, infl, 512);
092 }
093
094 /**
095 * Creates a new output stream with the specified decompressor and
096 * buffer size.
097 *
098 * @param out output stream to write the uncompressed data to
099 * @param infl decompressor ("inflater") for this stream
100 * @param bufLen decompression buffer size
101 * @throws IllegalArgumentException if {@code bufLen} is <= 0
102 * @throws NullPointerException if {@code out} or {@code infl} is null
103 */
104 public InflaterOutputStream(OutputStream out, Inflater infl,
105 int bufLen) {
106 super (out);
107
108 // Sanity checks
109 if (out == null)
110 throw new NullPointerException("Null output");
111 if (infl == null)
112 throw new NullPointerException("Null inflater");
113 if (bufLen <= 0)
114 throw new IllegalArgumentException("Buffer size < 1");
115
116 // Initialize
117 inf = infl;
118 buf = new byte[bufLen];
119 }
120
121 /**
122 * Writes any remaining uncompressed data to the output stream and closes
123 * the underlying output stream.
124 *
125 * @throws IOException if an I/O error occurs
126 */
127 public void close() throws IOException {
128 if (!closed) {
129 // Complete the uncompressed output
130 try {
131 finish();
132 } finally {
133 out.close();
134 closed = true;
135 }
136 }
137 }
138
139 /**
140 * Flushes this output stream, forcing any pending buffered output bytes to be
141 * written.
142 *
143 * @throws IOException if an I/O error occurs or this stream is already
144 * closed
145 */
146 public void flush() throws IOException {
147 ensureOpen();
148
149 // Finish decompressing and writing pending output data
150 if (!inf.finished()) {
151 try {
152 while (!inf.finished() && !inf.needsInput()) {
153 int n;
154
155 // Decompress pending output data
156 n = inf.inflate(buf, 0, buf.length);
157 if (n < 1) {
158 break;
159 }
160
161 // Write the uncompressed output data block
162 out.write(buf, 0, n);
163 }
164 super .flush();
165 } catch (DataFormatException ex) {
166 // Improperly formatted compressed (ZIP) data
167 String msg = ex.getMessage();
168 if (msg == null) {
169 msg = "Invalid ZLIB data format";
170 }
171 throw new ZipException(msg);
172 }
173 }
174 }
175
176 /**
177 * Finishes writing uncompressed data to the output stream without closing
178 * the underlying stream. Use this method when applying multiple filters in
179 * succession to the same output stream.
180 *
181 * @throws IOException if an I/O error occurs or this stream is already
182 * closed
183 */
184 public void finish() throws IOException {
185 ensureOpen();
186
187 // Finish decompressing and writing pending output data
188 flush();
189 if (usesDefaultInflater) {
190 inf.end();
191 }
192 }
193
194 /**
195 * Writes a byte to the uncompressed output stream.
196 *
197 * @param b a single byte of compressed data to decompress and write to
198 * the output stream
199 * @throws IOException if an I/O error occurs or this stream is already
200 * closed
201 * @throws ZipException if a compression (ZIP) format error occurs
202 */
203 public void write(int b) throws IOException {
204 // Write a single byte of data
205 wbuf[0] = (byte) b;
206 write(wbuf, 0, 1);
207 }
208
209 /**
210 * Writes an array of bytes to the uncompressed output stream.
211 *
212 * @param b buffer containing compressed data to decompress and write to
213 * the output stream
214 * @param off starting offset of the compressed data within {@code b}
215 * @param len number of bytes to decompress from {@code b}
216 * @throws IndexOutOfBoundsException if {@code off} < 0, or if
217 * {@code len} < 0, or if {@code len} > {@code b.length - off}
218 * @throws IOException if an I/O error occurs or this stream is already
219 * closed
220 * @throws NullPointerException if {@code b} is null
221 * @throws ZipException if a compression (ZIP) format error occurs
222 */
223 public void write(byte[] b, int off, int len) throws IOException {
224 // Sanity checks
225 ensureOpen();
226 if (b == null) {
227 throw new NullPointerException("Null buffer for read");
228 } else if (off < 0 || len < 0 || len > b.length - off) {
229 throw new IndexOutOfBoundsException();
230 } else if (len == 0) {
231 return;
232 }
233
234 // Write uncompressed data to the output stream
235 try {
236 for (;;) {
237 int n;
238
239 // Fill the decompressor buffer with output data
240 if (inf.needsInput()) {
241 int part;
242
243 if (len < 1) {
244 break;
245 }
246
247 part = (len < 512 ? len : 512);
248 inf.setInput(b, off, part);
249 off += part;
250 len -= part;
251 }
252
253 // Decompress and write blocks of output data
254 do {
255 n = inf.inflate(buf, 0, buf.length);
256 if (n > 0) {
257 out.write(buf, 0, n);
258 }
259 } while (n > 0);
260
261 // Check the decompressor
262 if (inf.finished()) {
263 break;
264 }
265 if (inf.needsDictionary()) {
266 throw new ZipException("ZLIB dictionary missing");
267 }
268 }
269 } catch (DataFormatException ex) {
270 // Improperly formatted compressed (ZIP) data
271 String msg = ex.getMessage();
272 if (msg == null) {
273 msg = "Invalid ZLIB data format";
274 }
275 throw new ZipException(msg);
276 }
277 }
278 }
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