J. Duke | 319a3b9 | 2007-12-01 00:00:00 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 1996-2006 Sun Microsystems, Inc. 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. Sun designates this |
| 8 | * particular file as subject to the "Classpath" exception as provided |
| 9 | * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
| 22 | * CA 95054 USA or visit www.sun.com if you need additional information or |
| 23 | * have any questions. |
| 24 | */ |
| 25 | |
| 26 | package java.util.zip; |
| 27 | |
| 28 | import java.io.FilterInputStream; |
| 29 | import java.io.InputStream; |
| 30 | import java.io.IOException; |
| 31 | import java.io.EOFException; |
| 32 | |
| 33 | /** |
| 34 | * This class implements a stream filter for uncompressing data in the |
| 35 | * "deflate" compression format. It is also used as the basis for other |
| 36 | * decompression filters, such as GZIPInputStream. |
| 37 | * |
| 38 | * @see Inflater |
| 39 | * @author David Connelly |
| 40 | */ |
| 41 | public |
| 42 | class InflaterInputStream extends FilterInputStream { |
| 43 | /** |
| 44 | * Decompressor for this stream. |
| 45 | */ |
| 46 | protected Inflater inf; |
| 47 | |
| 48 | /** |
| 49 | * Input buffer for decompression. |
| 50 | */ |
| 51 | protected byte[] buf; |
| 52 | |
| 53 | /** |
| 54 | * Length of input buffer. |
| 55 | */ |
| 56 | protected int len; |
| 57 | |
| 58 | private boolean closed = false; |
| 59 | // this flag is set to true after EOF has reached |
| 60 | private boolean reachEOF = false; |
| 61 | |
| 62 | /** |
| 63 | * Check to make sure that this stream has not been closed |
| 64 | */ |
| 65 | private void ensureOpen() throws IOException { |
| 66 | if (closed) { |
| 67 | throw new IOException("Stream closed"); |
| 68 | } |
| 69 | } |
| 70 | |
| 71 | |
| 72 | /** |
| 73 | * Creates a new input stream with the specified decompressor and |
| 74 | * buffer size. |
| 75 | * @param in the input stream |
| 76 | * @param inf the decompressor ("inflater") |
| 77 | * @param size the input buffer size |
| 78 | * @exception IllegalArgumentException if size is <= 0 |
| 79 | */ |
| 80 | public InflaterInputStream(InputStream in, Inflater inf, int size) { |
| 81 | super(in); |
| 82 | if (in == null || inf == null) { |
| 83 | throw new NullPointerException(); |
| 84 | } else if (size <= 0) { |
| 85 | throw new IllegalArgumentException("buffer size <= 0"); |
| 86 | } |
| 87 | this.inf = inf; |
| 88 | buf = new byte[size]; |
| 89 | } |
| 90 | |
| 91 | /** |
| 92 | * Creates a new input stream with the specified decompressor and a |
| 93 | * default buffer size. |
| 94 | * @param in the input stream |
| 95 | * @param inf the decompressor ("inflater") |
| 96 | */ |
| 97 | public InflaterInputStream(InputStream in, Inflater inf) { |
| 98 | this(in, inf, 512); |
| 99 | } |
| 100 | |
| 101 | boolean usesDefaultInflater = false; |
| 102 | |
| 103 | /** |
| 104 | * Creates a new input stream with a default decompressor and buffer size. |
| 105 | * @param in the input stream |
| 106 | */ |
| 107 | public InflaterInputStream(InputStream in) { |
| 108 | this(in, new Inflater()); |
| 109 | usesDefaultInflater = true; |
| 110 | } |
| 111 | |
| 112 | private byte[] singleByteBuf = new byte[1]; |
| 113 | |
| 114 | /** |
| 115 | * Reads a byte of uncompressed data. This method will block until |
| 116 | * enough input is available for decompression. |
| 117 | * @return the byte read, or -1 if end of compressed input is reached |
| 118 | * @exception IOException if an I/O error has occurred |
| 119 | */ |
| 120 | public int read() throws IOException { |
| 121 | ensureOpen(); |
| 122 | return read(singleByteBuf, 0, 1) == -1 ? -1 : singleByteBuf[0] & 0xff; |
| 123 | } |
| 124 | |
| 125 | /** |
| 126 | * Reads uncompressed data into an array of bytes. If <code>len</code> is not |
| 127 | * zero, the method will block until some input can be decompressed; otherwise, |
| 128 | * no bytes are read and <code>0</code> is returned. |
| 129 | * @param b the buffer into which the data is read |
| 130 | * @param off the start offset in the destination array <code>b</code> |
| 131 | * @param len the maximum number of bytes read |
| 132 | * @return the actual number of bytes read, or -1 if the end of the |
| 133 | * compressed input is reached or a preset dictionary is needed |
| 134 | * @exception NullPointerException If <code>b</code> is <code>null</code>. |
| 135 | * @exception IndexOutOfBoundsException If <code>off</code> is negative, |
| 136 | * <code>len</code> is negative, or <code>len</code> is greater than |
| 137 | * <code>b.length - off</code> |
| 138 | * @exception ZipException if a ZIP format error has occurred |
| 139 | * @exception IOException if an I/O error has occurred |
| 140 | */ |
| 141 | public int read(byte[] b, int off, int len) throws IOException { |
| 142 | ensureOpen(); |
| 143 | if (b == null) { |
| 144 | throw new NullPointerException(); |
| 145 | } else if (off < 0 || len < 0 || len > b.length - off) { |
| 146 | throw new IndexOutOfBoundsException(); |
| 147 | } else if (len == 0) { |
| 148 | return 0; |
| 149 | } |
| 150 | try { |
| 151 | int n; |
| 152 | while ((n = inf.inflate(b, off, len)) == 0) { |
| 153 | if (inf.finished() || inf.needsDictionary()) { |
| 154 | reachEOF = true; |
| 155 | return -1; |
| 156 | } |
| 157 | if (inf.needsInput()) { |
| 158 | fill(); |
| 159 | } |
| 160 | } |
| 161 | return n; |
| 162 | } catch (DataFormatException e) { |
| 163 | String s = e.getMessage(); |
| 164 | throw new ZipException(s != null ? s : "Invalid ZLIB data format"); |
| 165 | } |
| 166 | } |
| 167 | |
| 168 | /** |
| 169 | * Returns 0 after EOF has been reached, otherwise always return 1. |
| 170 | * <p> |
| 171 | * Programs should not count on this method to return the actual number |
| 172 | * of bytes that could be read without blocking. |
| 173 | * |
| 174 | * @return 1 before EOF and 0 after EOF. |
| 175 | * @exception IOException if an I/O error occurs. |
| 176 | * |
| 177 | */ |
| 178 | public int available() throws IOException { |
| 179 | ensureOpen(); |
| 180 | if (reachEOF) { |
| 181 | return 0; |
| 182 | } else { |
| 183 | return 1; |
| 184 | } |
| 185 | } |
| 186 | |
| 187 | private byte[] b = new byte[512]; |
| 188 | |
| 189 | /** |
| 190 | * Skips specified number of bytes of uncompressed data. |
| 191 | * @param n the number of bytes to skip |
| 192 | * @return the actual number of bytes skipped. |
| 193 | * @exception IOException if an I/O error has occurred |
| 194 | * @exception IllegalArgumentException if n < 0 |
| 195 | */ |
| 196 | public long skip(long n) throws IOException { |
| 197 | if (n < 0) { |
| 198 | throw new IllegalArgumentException("negative skip length"); |
| 199 | } |
| 200 | ensureOpen(); |
| 201 | int max = (int)Math.min(n, Integer.MAX_VALUE); |
| 202 | int total = 0; |
| 203 | while (total < max) { |
| 204 | int len = max - total; |
| 205 | if (len > b.length) { |
| 206 | len = b.length; |
| 207 | } |
| 208 | len = read(b, 0, len); |
| 209 | if (len == -1) { |
| 210 | reachEOF = true; |
| 211 | break; |
| 212 | } |
| 213 | total += len; |
| 214 | } |
| 215 | return total; |
| 216 | } |
| 217 | |
| 218 | /** |
| 219 | * Closes this input stream and releases any system resources associated |
| 220 | * with the stream. |
| 221 | * @exception IOException if an I/O error has occurred |
| 222 | */ |
| 223 | public void close() throws IOException { |
| 224 | if (!closed) { |
| 225 | if (usesDefaultInflater) |
| 226 | inf.end(); |
| 227 | in.close(); |
| 228 | closed = true; |
| 229 | } |
| 230 | } |
| 231 | |
| 232 | /** |
| 233 | * Fills input buffer with more data to decompress. |
| 234 | * @exception IOException if an I/O error has occurred |
| 235 | */ |
| 236 | protected void fill() throws IOException { |
| 237 | ensureOpen(); |
| 238 | len = in.read(buf, 0, buf.length); |
| 239 | if (len == -1) { |
| 240 | throw new EOFException("Unexpected end of ZLIB input stream"); |
| 241 | } |
| 242 | inf.setInput(buf, 0, len); |
| 243 | } |
| 244 | |
| 245 | /** |
| 246 | * Tests if this input stream supports the <code>mark</code> and |
| 247 | * <code>reset</code> methods. The <code>markSupported</code> |
| 248 | * method of <code>InflaterInputStream</code> returns |
| 249 | * <code>false</code>. |
| 250 | * |
| 251 | * @return a <code>boolean</code> indicating if this stream type supports |
| 252 | * the <code>mark</code> and <code>reset</code> methods. |
| 253 | * @see java.io.InputStream#mark(int) |
| 254 | * @see java.io.InputStream#reset() |
| 255 | */ |
| 256 | public boolean markSupported() { |
| 257 | return false; |
| 258 | } |
| 259 | |
| 260 | /** |
| 261 | * Marks the current position in this input stream. |
| 262 | * |
| 263 | * <p> The <code>mark</code> method of <code>InflaterInputStream</code> |
| 264 | * does nothing. |
| 265 | * |
| 266 | * @param readlimit the maximum limit of bytes that can be read before |
| 267 | * the mark position becomes invalid. |
| 268 | * @see java.io.InputStream#reset() |
| 269 | */ |
| 270 | public synchronized void mark(int readlimit) { |
| 271 | } |
| 272 | |
| 273 | /** |
| 274 | * Repositions this stream to the position at the time the |
| 275 | * <code>mark</code> method was last called on this input stream. |
| 276 | * |
| 277 | * <p> The method <code>reset</code> for class |
| 278 | * <code>InflaterInputStream</code> does nothing except throw an |
| 279 | * <code>IOException</code>. |
| 280 | * |
| 281 | * @exception IOException if this method is invoked. |
| 282 | * @see java.io.InputStream#mark(int) |
| 283 | * @see java.io.IOException |
| 284 | */ |
| 285 | public synchronized void reset() throws IOException { |
| 286 | throw new IOException("mark/reset not supported"); |
| 287 | } |
| 288 | } |