1 /* 2 * Copyright (c) 1996, 2009, 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 */ 41 public 42 class DeflaterOutputStream extends FilterOutputStream { 43 /** 44 * Compressor for this stream. 45 */ 46 protected Deflater def; 47 48 /** 49 * Output buffer for writing compressed data. 50 */ 51 protected byte[] buf; 52 53 /** 54 * Indicates that the stream has been closed. 55 */ 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 size is <= 0 75 * 76 * @since 1.7 77 */ 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 * @exception IllegalArgumentException if size is <= 0 105 */ 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 */ 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 */ 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 */ 161 public DeflaterOutputStream(OutputStream out, boolean syncFlush) { 162 this(out, new Deflater(), 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 */ 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 * @exception IOException if an I/O error has occurred 184 */ 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 * @exception IOException if an I/O error has occurred 198 */ 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 // Deflate no more than stride bytes at a time. This avoids 210 // excess copying in deflateBytes (see Deflater.c) 211 int stride = buf.length; 212 for (int i = 0; i < len; i+= stride) { 213 def.setInput(b, off + i, Math.min(stride, len - i)); 214 while (!def.needsInput()) { 215 deflate(); 216 } 217 } 218 } 219 } 220 221 /** 222 * Finishes writing compressed data to the output stream without closing 223 * the underlying stream. Use this method when applying multiple filters 224 * in succession to the same output stream. 225 * @exception IOException if an I/O error has occurred 226 */ 227 public void finish() throws IOException { 228 if (!def.finished()) { 229 def.finish(); 230 while (!def.finished()) { 231 deflate(); 232 } 233 } 234 } 235 236 /** 237 * Writes remaining compressed data to the output stream and closes the 238 * underlying stream. 239 * @exception IOException if an I/O error has occurred 240 */ 241 public void close() throws IOException { 242 if (!closed) { 243 finish(); 244 if (usesDefaultDeflater) 245 def.end(); 246 out.close(); 247 closed = true; 248 } 249 } 250 251 /** 252 * Writes next block of compressed data to the output stream. 253 * @throws IOException if an I/O error has occurred 254 */ 255 protected void deflate() throws IOException { 256 int len = def.deflate(buf, 0, buf.length); 257 if (len > 0) { 258 out.write(buf, 0, len); 259 } 260 } 261 262 /** 263 * Flushes the compressed output stream. 264 * 265 * If {@link #DeflaterOutputStream(OutputStream, Deflater, int, boolean) 266 * syncFlush} is {@code true} when this compressed output stream is 267 * constructed, this method first flushes the underlying {@code compressor} 268 * with the flush mode {@link Deflater#SYNC_FLUSH} to force 269 * all pending data to be flushed out to the output stream and then 270 * flushes the output stream. Otherwise this method only flushes the 271 * output stream without flushing the {@code compressor}. 272 * 273 * @throws IOException if an I/O error has occurred 274 * 275 * @since 1.7 276 */ 277 public void flush() throws IOException { 278 if (syncFlush && !def.finished()) { 279 int len = 0; 280 while ((len = def.deflate(buf, 0, buf.length, Deflater.SYNC_FLUSH)) > 0) 281 { 282 out.write(buf, 0, len); 283 if (len < buf.length) 284 break; 285 } 286 } 287 out.flush(); 288 } 289 }