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| 1 | /* | ||
| 2 | * Copyright (c) 2006, 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.FilterInputStream; | ||
| 29 | import java.io.InputStream; | ||
| 30 | import java.io.IOException; | ||
| 31 | |||
| 32 | /** | ||
| 33 | * Implements an input stream filter for compressing data in the "deflate" | ||
| 34 | * compression format. | ||
| 35 | * | ||
| 36 | * @since 1.6 | ||
| 37 | * @author David R Tribble (david@tribble.com) | ||
| 38 | * | ||
| 39 | * @see DeflaterOutputStream | ||
| 40 | * @see InflaterOutputStream | ||
| 41 | * @see InflaterInputStream | ||
| 42 | */ | ||
| 43 | |||
| 44 | public class DeflaterInputStream extends FilterInputStream { | ||
| 45 | /** Compressor for this stream. */ | ||
| 46 | protected final Deflater def; | ||
| 47 | |||
| 48 | /** Input buffer for reading compressed data. */ | ||
| 49 | protected final byte[] buf; | ||
| 50 | |||
| 51 | /** Temporary read buffer. */ | ||
| 52 | private byte[] rbuf = new byte[1]; | ||
| 53 | |||
| 54 | /** Default compressor is used. */ | ||
| 55 | private boolean usesDefaultDeflater = false; | ||
| 56 | |||
| 57 | /** End of the underlying input stream has been reached. */ | ||
| 58 | private boolean reachEOF = false; | ||
| 59 | |||
| 60 | /** | ||
| 61 | * Check to make sure that this stream has not been closed. | ||
| 62 | */ | ||
| 63 | private void ensureOpen() throws IOException { | ||
| 64 | if (in == null) { | ||
| 65 | throw new IOException("Stream closed"); | ||
| 66 | } | ||
| 67 | } | ||
| 68 | |||
| 69 | /** | ||
| 70 | * Creates a new input stream with a default compressor and buffer | ||
| 71 | * size. | ||
| 72 | * | ||
| 73 | * @param in input stream to read the uncompressed data to | ||
| 74 | * @throws NullPointerException if {@code in} is null | ||
| 75 | */ | ||
| 76 | public DeflaterInputStream(InputStream in) { | ||
| 77 | this(in, new Deflater()); | ||
| 78 | usesDefaultDeflater = true; | ||
| 79 | } | ||
| 80 | |||
| 81 | /** | ||
| 82 | * Creates a new input stream with the specified compressor and a | ||
| 83 | * default buffer size. | ||
| 84 | * | ||
| 85 | * @param in input stream to read the uncompressed data to | ||
| 86 | * @param defl compressor ("deflater") for this stream | ||
| 87 | * @throws NullPointerException if {@code in} or {@code defl} is null | ||
| 88 | */ | ||
| 89 | public DeflaterInputStream(InputStream in, Deflater defl) { | ||
| 90 | this(in, defl, 512); | ||
| 91 | } | ||
| 92 | |||
| 93 | /** | ||
| 94 | * Creates a new input stream with the specified compressor and buffer | ||
| 95 | * size. | ||
| 96 | * | ||
| 97 | * @param in input stream to read the uncompressed data to | ||
| 98 | * @param defl compressor ("deflater") for this stream | ||
| 99 | * @param bufLen compression buffer size | ||
| 100 | * @throws IllegalArgumentException if {@code bufLen} is <= 0 | ||
| 101 | * @throws NullPointerException if {@code in} or {@code defl} is null | ||
| 102 | */ | ||
| 103 | public DeflaterInputStream(InputStream in, Deflater defl, int bufLen) { | ||
| 104 | super(in); | ||
| 105 | |||
| 106 | // Sanity checks | ||
| 107 | if (in == null) | ||
| 108 | throw new NullPointerException("Null input"); | ||
| 109 | if (defl == null) | ||
| 110 | throw new NullPointerException("Null deflater"); | ||
| 111 | if (bufLen < 1) | ||
| 112 | throw new IllegalArgumentException("Buffer size < 1"); | ||
| 113 | |||
| 114 | // Initialize | ||
| 115 | def = defl; | ||
| 116 | buf = new byte[bufLen]; | ||
| 117 | } | ||
| 118 | |||
| 119 | /** | ||
| 120 | * Closes this input stream and its underlying input stream, discarding | ||
| 121 | * any pending uncompressed data. | ||
| 122 | * | ||
| 123 | * @throws IOException if an I/O error occurs | ||
| 124 | */ | ||
| 125 | public void close() throws IOException { | ||
| 126 | if (in != null) { | ||
| 127 | try { | ||
| 128 | // Clean up | ||
| 129 | if (usesDefaultDeflater) { | ||
| 130 | def.end(); | ||
| 131 | } | ||
| 132 | |||
| 133 | in.close(); | ||
| 134 | } finally { | ||
| 135 | in = null; | ||
| 136 | } | ||
| 137 | } | ||
| 138 | } | ||
| 139 | |||
| 140 | /** | ||
| 141 | * Reads a single byte of compressed data from the input stream. | ||
| 142 | * This method will block until some input can be read and compressed. | ||
| 143 | * | ||
| 144 | * @return a single byte of compressed data, or -1 if the end of the | ||
| 145 | * uncompressed input stream is reached | ||
| 146 | * @throws IOException if an I/O error occurs or if this stream is | ||
| 147 | * already closed | ||
| 148 | */ | ||
| 149 | public int read() throws IOException { | ||
| 150 | // Read a single byte of compressed data | ||
| 151 | int len = read(rbuf, 0, 1); | ||
| 152 | if (len <= 0) | ||
| 153 | return -1; | ||
| 154 | return (rbuf[0] & 0xFF); | ||
| 155 | } | ||
| 156 | |||
| 157 | /** | ||
| 158 | * Reads compressed data into a byte array. | ||
| 159 | * This method will block until some input can be read and compressed. | ||
| 160 | * | ||
| 161 | * @param b buffer into which the data is read | ||
| 162 | * @param off starting offset of the data within {@code b} | ||
| 163 | * @param len maximum number of compressed bytes to read into {@code b} | ||
| 164 | * @return the actual number of bytes read, or -1 if the end of the | ||
| 165 | * uncompressed input stream is reached | ||
| 166 | * @throws IndexOutOfBoundsException if {@code len} > {@code b.length - | ||
| 167 | * off} | ||
| 168 | * @throws IOException if an I/O error occurs or if this input stream is | ||
| 169 | * already closed | ||
| 170 | */ | ||
| 171 | public int read(byte[] b, int off, int len) throws IOException { | ||
| 172 | // Sanity checks | ||
| 173 | ensureOpen(); | ||
| 174 | if (b == null) { | ||
| 175 | throw new NullPointerException("Null buffer for read"); | ||
| 176 | } else if (off < 0 || len < 0 || len > b.length - off) { | ||
| 177 | throw new IndexOutOfBoundsException(); | ||
| 178 | } else if (len == 0) { | ||
| 179 | return 0; | ||
| 180 | } | ||
| 181 | |||
| 182 | // Read and compress (deflate) input data bytes | ||
| 183 | int cnt = 0; | ||
| 184 | while (len > 0 && !def.finished()) { | ||
| 185 | int n; | ||
| 186 | |||
| 187 | // Read data from the input stream | ||
| 188 | if (def.needsInput()) { | ||
| 189 | n = in.read(buf, 0, buf.length); | ||
| 190 | if (n < 0) { | ||
| 191 | // End of the input stream reached | ||
| 192 | def.finish(); | ||
| 193 | } else if (n > 0) { | ||
| 194 | def.setInput(buf, 0, n); | ||
| 195 | } | ||
| 196 | } | ||
| 197 | |||
| 198 | // Compress the input data, filling the read buffer | ||
| 199 | n = def.deflate(b, off, len); | ||
| 200 | cnt += n; | ||
| 201 | off += n; | ||
| 202 | len -= n; | ||
| 203 | } | ||
| 204 | if (cnt == 0 && def.finished()) { | ||
| 205 | reachEOF = true; | ||
| 206 | cnt = -1; | ||
| 207 | } | ||
| 208 | |||
| 209 | return cnt; | ||
| 210 | } | ||
| 211 | |||
| 212 | /** | ||
| 213 | * Skips over and discards data from the input stream. | ||
| 214 | * This method may block until the specified number of bytes are read and | ||
| 215 | * skipped. <em>Note:</em> While {@code n} is given as a {@code long}, | ||
| 216 | * the maximum number of bytes which can be skipped is | ||
| 217 | * {@code Integer.MAX_VALUE}. | ||
| 218 | * | ||
| 219 | * @param n number of bytes to be skipped | ||
| 220 | * @return the actual number of bytes skipped | ||
| 221 | * @throws IOException if an I/O error occurs or if this stream is | ||
| 222 | * already closed | ||
| 223 | */ | ||
| 224 | public long skip(long n) throws IOException { | ||
| 225 | if (n < 0) { | ||
| 226 | throw new IllegalArgumentException("negative skip length"); | ||
| 227 | } | ||
| 228 | ensureOpen(); | ||
| 229 | |||
| 230 | // Skip bytes by repeatedly decompressing small blocks | ||
| 231 | if (rbuf.length < 512) | ||
| 232 | rbuf = new byte[512]; | ||
| 233 | |||
| 234 | int total = (int)Math.min(n, Integer.MAX_VALUE); | ||
| 235 | long cnt = 0; | ||
| 236 | while (total > 0) { | ||
| 237 | // Read a small block of uncompressed bytes | ||
| 238 | int len = read(rbuf, 0, (total <= rbuf.length ? total : rbuf.length)); | ||
| 239 | |||
| 240 | if (len < 0) { | ||
| 241 | break; | ||
| 242 | } | ||
| 243 | cnt += len; | ||
| 244 | total -= len; | ||
| 245 | } | ||
| 246 | return cnt; | ||
| 247 | } | ||
| 248 | |||
| 249 | /** | ||
| 250 | * Returns 0 after EOF has been reached, otherwise always return 1. | ||
| 251 | * <p> | ||
| 252 | * Programs should not count on this method to return the actual number | ||
| 253 | * of bytes that could be read without blocking | ||
| 254 | * @return zero after the end of the underlying input stream has been | ||
| 255 | * reached, otherwise always returns 1 | ||
| 256 | * @throws IOException if an I/O error occurs or if this stream is | ||
| 257 | * already closed | ||
| 258 | */ | ||
| 259 | public int available() throws IOException { | ||
| 260 | ensureOpen(); | ||
| 261 | if (reachEOF) { | ||
| 262 | return 0; | ||
| 263 | } | ||
| 264 | return 1; | ||
| 265 | } | ||
| 266 | |||
| 267 | /** | ||
| 268 | * Always returns {@code false} because this input stream does not support | ||
| 269 | * the {@link #mark mark()} and {@link #reset reset()} methods. | ||
| 270 | * | ||
| 271 | * @return false, always | ||
| 272 | */ | ||
| 273 | public boolean markSupported() { | ||
| 274 | return false; | ||
| 275 | } | ||
| 276 | |||
| 277 | /** | ||
| 278 | * <i>This operation is not supported</i>. | ||
| 279 | * | ||
| 280 | * @param limit maximum bytes that can be read before invalidating the position marker | ||
| 281 | */ | ||
| 282 | public void mark(int limit) { | ||
| 283 | // Operation not supported | ||
| 284 | } | ||
| 285 | |||
| 286 | /** | ||
| 287 | * <i>This operation is not supported</i>. | ||
| 288 | * | ||
| 289 | * @throws IOException always thrown | ||
| 290 | */ | ||
| 291 | public void reset() throws IOException { | ||
| 292 | throw new IOException("mark/reset not supported"); | ||
| 293 | } | ||
| 294 | } | ||