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4  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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12  * This code is distributed in the hope that it will be useful, but WITHOUT
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14  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
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26 
27 package java.util.zip;
28 
29 import java.io.FilterOutputStream;
30 import java.io.OutputStream;
31 import java.io.InputStream;
32 import java.io.IOException;
33 
34 /**
35  * This class implements an output stream filter for compressing data in
36  * the "deflate" compression format. It is also used as the basis for other
37  * types of compression filters, such as GZIPOutputStream.
38  *
39  * @see         Deflater
40  * @author      David Connelly
41  * @since 1.1
42  */
43 public class DeflaterOutputStream extends FilterOutputStream {
44     /**
45      * Compressor for this stream.
46      */
47     protected Deflater def;
48 
49     /**
50      * Output buffer for writing compressed data.
51      */
52     protected byte[] buf;
53 
54     /**
55      * Indicates that the stream has been closed.
56      */
57     private boolean closed = false;
58 
59     private final boolean syncFlush;
60 
61     /**
62      * Creates a new output stream with the specified compressor,
63      * buffer size and flush mode.
64      *
65      * @param out the output stream
66      * @param def the compressor ("deflater")
67      * @param size the output buffer size
68      * @param syncFlush
69      *        if {@code true} the {@link #flush()} method of this
70      *        instance flushes the compressor with flush mode
71      *        {@link Deflater#SYNC_FLUSH} before flushing the output
72      *        stream, otherwise only flushes the output stream
73      *
74      * @throws IllegalArgumentException if {@code size <= 0}
75      *
76      * @since 1.7
77      */
DeflaterOutputStream(OutputStream out, Deflater def, int size, boolean syncFlush)78     public DeflaterOutputStream(OutputStream out,
79                                 Deflater def,
80                                 int size,
81                                 boolean syncFlush) {
82         super(out);
83         if (out == null || def == null) {
84             throw new NullPointerException();
85         } else if (size <= 0) {
86             throw new IllegalArgumentException("buffer size <= 0");
87         }
88         this.def = def;
89         this.buf = new byte[size];
90         this.syncFlush = syncFlush;
91     }
92 
93 
94     /**
95      * Creates a new output stream with the specified compressor and
96      * buffer size.
97      *
98      * <p>The new output stream instance is created as if by invoking
99      * the 4-argument constructor DeflaterOutputStream(out, def, size, false).
100      *
101      * @param out the output stream
102      * @param def the compressor ("deflater")
103      * @param size the output buffer size
104      * @throws    IllegalArgumentException if {@code size <= 0}
105      */
DeflaterOutputStream(OutputStream out, Deflater def, int size)106     public DeflaterOutputStream(OutputStream out, Deflater def, int size) {
107         this(out, def, size, false);
108     }
109 
110     /**
111      * Creates a new output stream with the specified compressor, flush
112      * mode and a default buffer size.
113      *
114      * @param out the output stream
115      * @param def the compressor ("deflater")
116      * @param syncFlush
117      *        if {@code true} the {@link #flush()} method of this
118      *        instance flushes the compressor with flush mode
119      *        {@link Deflater#SYNC_FLUSH} before flushing the output
120      *        stream, otherwise only flushes the output stream
121      *
122      * @since 1.7
123      */
DeflaterOutputStream(OutputStream out, Deflater def, boolean syncFlush)124     public DeflaterOutputStream(OutputStream out,
125                                 Deflater def,
126                                 boolean syncFlush) {
127         this(out, def, 512, syncFlush);
128     }
129 
130 
131     /**
132      * Creates a new output stream with the specified compressor and
133      * a default buffer size.
134      *
135      * <p>The new output stream instance is created as if by invoking
136      * the 3-argument constructor DeflaterOutputStream(out, def, false).
137      *
138      * @param out the output stream
139      * @param def the compressor ("deflater")
140      */
DeflaterOutputStream(OutputStream out, Deflater def)141     public DeflaterOutputStream(OutputStream out, Deflater def) {
142         this(out, def, 512, false);
143     }
144 
145     boolean usesDefaultDeflater = false;
146 
147 
148     /**
149      * Creates a new output stream with a default compressor, a default
150      * buffer size and the specified flush mode.
151      *
152      * @param out the output stream
153      * @param syncFlush
154      *        if {@code true} the {@link #flush()} method of this
155      *        instance flushes the compressor with flush mode
156      *        {@link Deflater#SYNC_FLUSH} before flushing the output
157      *        stream, otherwise only flushes the output stream
158      *
159      * @since 1.7
160      */
DeflaterOutputStream(OutputStream out, boolean syncFlush)161     public DeflaterOutputStream(OutputStream out, boolean syncFlush) {
162         this(out, out != null ? new Deflater() : null, 512, syncFlush);
163         usesDefaultDeflater = true;
164     }
165 
166     /**
167      * Creates a new output stream with a default compressor and buffer size.
168      *
169      * <p>The new output stream instance is created as if by invoking
170      * the 2-argument constructor DeflaterOutputStream(out, false).
171      *
172      * @param out the output stream
173      */
DeflaterOutputStream(OutputStream out)174     public DeflaterOutputStream(OutputStream out) {
175         this(out, false);
176         usesDefaultDeflater = true;
177     }
178 
179     /**
180      * Writes a byte to the compressed output stream. This method will
181      * block until the byte can be written.
182      * @param b the byte to be written
183      * @throws    IOException if an I/O error has occurred
184      */
write(int b)185     public void write(int b) throws IOException {
186         byte[] buf = new byte[1];
187         buf[0] = (byte)(b & 0xff);
188         write(buf, 0, 1);
189     }
190 
191     /**
192      * Writes an array of bytes to the compressed output stream. This
193      * method will block until all the bytes are written.
194      * @param b the data to be written
195      * @param off the start offset of the data
196      * @param len the length of the data
197      * @throws    IOException if an I/O error has occurred
198      */
write(byte[] b, int off, int len)199     public void write(byte[] b, int off, int len) throws IOException {
200         if (def.finished()) {
201             throw new IOException("write beyond end of stream");
202         }
203         if ((off | len | (off + len) | (b.length - (off + len))) < 0) {
204             throw new IndexOutOfBoundsException();
205         } else if (len == 0) {
206             return;
207         }
208         if (!def.finished()) {
209             def.setInput(b, off, len);
210             while (!def.needsInput()) {
211                 deflate();
212             }
213         }
214     }
215 
216     /**
217      * Finishes writing compressed data to the output stream without closing
218      * the underlying stream. Use this method when applying multiple filters
219      * in succession to the same output stream.
220      * @throws    IOException if an I/O error has occurred
221      */
finish()222     public void finish() throws IOException {
223         if (!def.finished()) {
224             try{
225                 def.finish();
226                 while (!def.finished()) {
227                     deflate();
228                 }
229             } catch(IOException e) {
230                 if (usesDefaultDeflater)
231                     def.end();
232                 throw e;
233             }
234         }
235     }
236 
237     /**
238      * Writes remaining compressed data to the output stream and closes the
239      * underlying stream.
240      * @throws    IOException if an I/O error has occurred
241      */
close()242     public void close() throws IOException {
243         if (!closed) {
244             try {
245                 finish();
246             } finally {
247                 if (usesDefaultDeflater)
248                     def.end();
249             }
250             out.close();
251             closed = true;
252         }
253     }
254 
255     /**
256      * Writes next block of compressed data to the output stream.
257      * @throws IOException if an I/O error has occurred
258      */
deflate()259     protected void deflate() throws IOException {
260         // Android-changed: Output all available compressed data (b/4005091).
261         // See http://b/111496419 for more details.
262         // int len = def.deflate(buf, 0, buf.length);
263         // if (len > 0) {
264         //     out.write(buf, 0, len);
265         // }
266         int len = 0;
267         while ((len = def.deflate(buf, 0, buf.length)) > 0) {
268           out.write(buf, 0, len);
269         }
270     }
271 
272     /**
273      * Flushes the compressed output stream.
274      *
275      * If {@link #DeflaterOutputStream(OutputStream, Deflater, int, boolean)
276      * syncFlush} is {@code true} when this compressed output stream is
277      * constructed, this method first flushes the underlying {@code compressor}
278      * with the flush mode {@link Deflater#SYNC_FLUSH} to force
279      * all pending data to be flushed out to the output stream and then
280      * flushes the output stream. Otherwise this method only flushes the
281      * output stream without flushing the {@code compressor}.
282      *
283      * @throws IOException if an I/O error has occurred
284      *
285      * @since 1.7
286      */
flush()287     public void flush() throws IOException {
288         if (syncFlush && !def.finished()) {
289             int len = 0;
290             while ((len = def.deflate(buf, 0, buf.length, Deflater.SYNC_FLUSH)) > 0)
291             {
292                 out.write(buf, 0, len);
293                 if (len < buf.length)
294                     break;
295             }
296         }
297         out.flush();
298     }
299 }
300