1 /*
   2  * Copyright (c) 1996, 2013, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 
  26 package java.util.zip;
  27 
  28 import java.io.FilterOutputStream;
  29 import java.io.OutputStream;
  30 import java.io.InputStream;
  31 import java.io.IOException;
  32 
  33 /**
  34  * This class implements an output stream filter for compressing data in
  35  * the "deflate" compression format. It is also used as the basis for other
  36  * types of compression filters, such as GZIPOutputStream.
  37  *
  38  * @see         Deflater
  39  * @author      David Connelly
  40  * @since 1.1
  41  */
  42 public
  43 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 
  58     private boolean closed = false;
  59 
  60     private final boolean syncFlush;
  61 
  62     /**
  63      * Creates a new output stream with the specified compressor,
  64      * buffer size and flush mode.
  65 
  66      * @param out the output stream
  67      * @param def the compressor ("deflater")
  68      * @param size the output buffer size
  69      * @param syncFlush
  70      *        if {@code true} the {@link #flush()} method of this
  71      *        instance flushes the compressor with flush mode
  72      *        {@link Deflater#SYNC_FLUSH} before flushing the output
  73      *        stream, otherwise only flushes the output stream
  74      *
  75      * @throws IllegalArgumentException if {@code size <= 0}
  76      *
  77      * @since 1.7
  78      */
  79     public DeflaterOutputStream(OutputStream out,
  80                                 Deflater def,
  81                                 int size,
  82                                 boolean syncFlush) {
  83         super(out);
  84         if (out == null || def == null) {
  85             throw new NullPointerException();
  86         } else if (size <= 0) {
  87             throw new IllegalArgumentException("buffer size <= 0");
  88         }
  89         this.def = def;
  90         this.buf = new byte[size];
  91         this.syncFlush = syncFlush;
  92     }
  93 
  94 
  95     /**
  96      * Creates a new output stream with the specified compressor and
  97      * buffer size.
  98      *
  99      * <p>The new output stream instance is created as if by invoking
 100      * the 4-argument constructor DeflaterOutputStream(out, def, size, false).
 101      *
 102      * @param out the output stream
 103      * @param def the compressor ("deflater")
 104      * @param size the output buffer size
 105      * @exception IllegalArgumentException if {@code size <= 0}
 106      */
 107     public DeflaterOutputStream(OutputStream out, Deflater def, int size) {
 108         this(out, def, size, false);
 109     }
 110 
 111     /**
 112      * Creates a new output stream with the specified compressor, flush
 113      * mode and a default buffer size.
 114      *
 115      * @param out the output stream
 116      * @param def the compressor ("deflater")
 117      * @param syncFlush
 118      *        if {@code true} the {@link #flush()} method of this
 119      *        instance flushes the compressor with flush mode
 120      *        {@link Deflater#SYNC_FLUSH} before flushing the output
 121      *        stream, otherwise only flushes the output stream
 122      *
 123      * @since 1.7
 124      */
 125     public DeflaterOutputStream(OutputStream out,
 126                                 Deflater def,
 127                                 boolean syncFlush) {
 128         this(out, def, 512, syncFlush);
 129     }
 130 
 131 
 132     /**
 133      * Creates a new output stream with the specified compressor and
 134      * a default buffer size.
 135      *
 136      * <p>The new output stream instance is created as if by invoking
 137      * the 3-argument constructor DeflaterOutputStream(out, def, false).
 138      *
 139      * @param out the output stream
 140      * @param def the compressor ("deflater")
 141      */
 142     public DeflaterOutputStream(OutputStream out, Deflater def) {
 143         this(out, def, 512, false);
 144     }
 145 
 146     boolean usesDefaultDeflater = false;
 147 
 148 
 149     /**
 150      * Creates a new output stream with a default compressor, a default
 151      * buffer size and the specified flush mode.
 152      *
 153      * @param out the output stream
 154      * @param syncFlush
 155      *        if {@code true} the {@link #flush()} method of this
 156      *        instance flushes the compressor with flush mode
 157      *        {@link Deflater#SYNC_FLUSH} before flushing the output
 158      *        stream, otherwise only flushes the output stream
 159      *
 160      * @since 1.7
 161      */
 162     public DeflaterOutputStream(OutputStream out, boolean syncFlush) {
 163         this(out, new Deflater(), 512, syncFlush);
 164         usesDefaultDeflater = true;
 165     }
 166 
 167     /**
 168      * Creates a new output stream with a default compressor and buffer size.
 169      *
 170      * <p>The new output stream instance is created as if by invoking
 171      * the 2-argument constructor DeflaterOutputStream(out, false).
 172      *
 173      * @param out the output stream
 174      */
 175     public DeflaterOutputStream(OutputStream out) {
 176         this(out, false);
 177         usesDefaultDeflater = true;
 178     }
 179 
 180     /**
 181      * Writes a byte to the compressed output stream. This method will
 182      * block until the byte can be written.
 183      * @param b the byte to be written
 184      * @exception IOException if an I/O error has occurred
 185      */
 186     public void write(int b) throws IOException {
 187         byte[] buf = new byte[1];
 188         buf[0] = (byte)(b & 0xff);
 189         write(buf, 0, 1);
 190     }
 191 
 192     /**
 193      * Writes an array of bytes to the compressed output stream. This
 194      * method will block until all the bytes are written.
 195      * @param b the data to be written
 196      * @param off the start offset of the data
 197      * @param len the length of the data
 198      * @exception IOException if an I/O error has occurred
 199      */
 200     public void write(byte[] b, int off, int len) throws IOException {
 201         if (def.finished()) {
 202             throw new IOException("write beyond end of stream");
 203         }
 204         if ((off | len | (off + len) | (b.length - (off + len))) < 0) {
 205             throw new IndexOutOfBoundsException();
 206         } else if (len == 0) {
 207             return;
 208         }
 209         if (!def.finished()) {
 210             def.setInput(b, off, len);
 211             while (!def.needsInput()) {
 212                 deflate();
 213             }
 214         }
 215     }
 216 
 217     /**
 218      * Finishes writing compressed data to the output stream without closing
 219      * the underlying stream. Use this method when applying multiple filters
 220      * in succession to the same output stream.
 221      * @exception IOException if an I/O error has occurred
 222      */
 223     public void finish() throws IOException {
 224         if (!def.finished()) {
 225             def.finish();
 226             while (!def.finished()) {
 227                 deflate();
 228             }
 229         }
 230     }
 231 
 232     /**
 233      * Writes remaining compressed data to the output stream and closes the
 234      * underlying stream.
 235      * @exception IOException if an I/O error has occurred
 236      */
 237     public void close() throws IOException {
 238         if (!closed) {
 239             finish();
 240             if (usesDefaultDeflater)
 241                 def.end();
 242             out.close();
 243             closed = true;
 244         }
 245     }
 246 
 247     /**
 248      * Writes next block of compressed data to the output stream.
 249      * @throws IOException if an I/O error has occurred
 250      */
 251     protected void deflate() throws IOException {
 252         int len = def.deflate(buf, 0, buf.length);
 253         if (len > 0) {
 254             out.write(buf, 0, len);
 255         }
 256     }
 257 
 258     /**
 259      * Flushes the compressed output stream.
 260      *
 261      * If {@link #DeflaterOutputStream(OutputStream, Deflater, int, boolean)
 262      * syncFlush} is {@code true} when this compressed output stream is
 263      * constructed, this method first flushes the underlying {@code compressor}
 264      * with the flush mode {@link Deflater#SYNC_FLUSH} to force
 265      * all pending data to be flushed out to the output stream and then
 266      * flushes the output stream. Otherwise this method only flushes the
 267      * output stream without flushing the {@code compressor}.
 268      *
 269      * @throws IOException if an I/O error has occurred
 270      *
 271      * @since 1.7
 272      */
 273     public void flush() throws IOException {
 274         if (syncFlush && !def.finished()) {
 275             int len = 0;
 276             while ((len = def.deflate(buf, 0, buf.length, Deflater.SYNC_FLUSH)) > 0)
 277             {
 278                 out.write(buf, 0, len);
 279                 if (len < buf.length)
 280                     break;
 281             }
 282         }
 283         out.flush();
 284     }
 285 }