| 1 | package be.nikiroo.utils.streams; |
| 2 | |
| 3 | import java.io.IOException; |
| 4 | import java.io.InputStream; |
| 5 | import java.util.Arrays; |
| 6 | |
| 7 | /** |
| 8 | * A simple {@link InputStream} that is buffered with a bytes array. |
| 9 | * <p> |
| 10 | * It is mostly intended to be used as a base class to create new |
| 11 | * {@link InputStream}s with special operation modes, and to give some default |
| 12 | * methods. |
| 13 | * |
| 14 | * @author niki |
| 15 | */ |
| 16 | public class BufferedInputStream extends InputStream { |
| 17 | /** |
| 18 | * The size of the internal buffer (can be different if you pass your own |
| 19 | * buffer, of course). |
| 20 | * <p> |
| 21 | * A second buffer of twice the size can sometimes be created as needed for |
| 22 | * the {@link BufferedInputStream#startsWith(byte[])} search operation. |
| 23 | */ |
| 24 | static private final int BUFFER_SIZE = 4096; |
| 25 | |
| 26 | /** The current position in the buffer. */ |
| 27 | protected int start; |
| 28 | /** The index of the last usable position of the buffer. */ |
| 29 | protected int stop; |
| 30 | /** The buffer itself. */ |
| 31 | protected byte[] buffer; |
| 32 | /** An End-Of-File (or {@link InputStream}, here) marker. */ |
| 33 | protected boolean eof; |
| 34 | |
| 35 | private boolean closed; |
| 36 | private InputStream in; |
| 37 | private int openCounter; |
| 38 | |
| 39 | // special use, prefetched next buffer |
| 40 | private byte[] buffer2; |
| 41 | private int pos2; |
| 42 | private int len2; |
| 43 | private byte[] originalBuffer; |
| 44 | |
| 45 | private long bytesRead; |
| 46 | |
| 47 | /** |
| 48 | * Create a new {@link BufferedInputStream} that wraps the given |
| 49 | * {@link InputStream}. |
| 50 | * |
| 51 | * @param in |
| 52 | * the {@link InputStream} to wrap |
| 53 | */ |
| 54 | public BufferedInputStream(InputStream in) { |
| 55 | this.in = in; |
| 56 | |
| 57 | this.buffer = new byte[BUFFER_SIZE]; |
| 58 | this.originalBuffer = this.buffer; |
| 59 | this.start = 0; |
| 60 | this.stop = 0; |
| 61 | } |
| 62 | |
| 63 | /** |
| 64 | * Create a new {@link BufferedInputStream} that wraps the given bytes array |
| 65 | * as a data source. |
| 66 | * |
| 67 | * @param in |
| 68 | * the array to wrap, cannot be NULL |
| 69 | */ |
| 70 | public BufferedInputStream(byte[] in) { |
| 71 | this(in, 0, in.length); |
| 72 | } |
| 73 | |
| 74 | /** |
| 75 | * Create a new {@link BufferedInputStream} that wraps the given bytes array |
| 76 | * as a data source. |
| 77 | * |
| 78 | * @param in |
| 79 | * the array to wrap, cannot be NULL |
| 80 | * @param offset |
| 81 | * the offset to start the reading at |
| 82 | * @param length |
| 83 | * the number of bytes to take into account in the array, |
| 84 | * starting from the offset |
| 85 | * |
| 86 | * @throws NullPointerException |
| 87 | * if the array is NULL |
| 88 | * @throws IndexOutOfBoundsException |
| 89 | * if the offset and length do not correspond to the given array |
| 90 | */ |
| 91 | public BufferedInputStream(byte[] in, int offset, int length) { |
| 92 | if (in == null) { |
| 93 | throw new NullPointerException(); |
| 94 | } else if (offset < 0 || length < 0 || length > in.length - offset) { |
| 95 | throw new IndexOutOfBoundsException(); |
| 96 | } |
| 97 | |
| 98 | this.in = null; |
| 99 | |
| 100 | this.buffer = in; |
| 101 | this.originalBuffer = this.buffer; |
| 102 | this.start = offset; |
| 103 | this.stop = length; |
| 104 | } |
| 105 | |
| 106 | /** |
| 107 | * Return this very same {@link BufferedInputStream}, but keep a counter of |
| 108 | * how many streams were open this way. When calling |
| 109 | * {@link BufferedInputStream#close()}, decrease this counter if it is not |
| 110 | * already zero instead of actually closing the stream. |
| 111 | * <p> |
| 112 | * You are now responsible for it — you <b>must</b> close it. |
| 113 | * <p> |
| 114 | * This method allows you to use a wrapping stream around this one and still |
| 115 | * close the wrapping stream. |
| 116 | * |
| 117 | * @return the same stream, but you are now responsible for closing it |
| 118 | * |
| 119 | * @throws IOException |
| 120 | * in case of I/O error or if the stream is closed |
| 121 | */ |
| 122 | public synchronized InputStream open() throws IOException { |
| 123 | checkClose(); |
| 124 | openCounter++; |
| 125 | return this; |
| 126 | } |
| 127 | |
| 128 | /** |
| 129 | * Check if the current content (what will be read next) starts with the |
| 130 | * given search term. |
| 131 | * <p> |
| 132 | * Note: the search term size <b>must</b> be smaller or equal the internal |
| 133 | * buffer size. |
| 134 | * |
| 135 | * @param search |
| 136 | * the term to search for |
| 137 | * |
| 138 | * @return TRUE if the content that will be read starts with it |
| 139 | * |
| 140 | * @throws IOException |
| 141 | * in case of I/O error or if the size of the search term is |
| 142 | * greater than the internal buffer |
| 143 | */ |
| 144 | public boolean startsWiths(String search) throws IOException { |
| 145 | return startsWith(search.getBytes("UTF-8")); |
| 146 | } |
| 147 | |
| 148 | /** |
| 149 | * Check if the current content (what will be read next) starts with the |
| 150 | * given search term. |
| 151 | * <p> |
| 152 | * Note: the search term size <b>must</b> be smaller or equal the internal |
| 153 | * buffer size. |
| 154 | * |
| 155 | * @param search |
| 156 | * the term to search for |
| 157 | * |
| 158 | * @return TRUE if the content that will be read starts with it |
| 159 | * |
| 160 | * @throws IOException |
| 161 | * in case of I/O error or if the size of the search term is |
| 162 | * greater than the internal buffer |
| 163 | */ |
| 164 | public boolean startsWith(byte[] search) throws IOException { |
| 165 | if (search.length > originalBuffer.length) { |
| 166 | throw new IOException( |
| 167 | "This stream does not support searching for more than " |
| 168 | + buffer.length + " bytes"); |
| 169 | } |
| 170 | |
| 171 | checkClose(); |
| 172 | |
| 173 | if (available() < search.length) { |
| 174 | preRead(); |
| 175 | } |
| 176 | |
| 177 | if (available() >= search.length) { |
| 178 | // Easy path |
| 179 | return StreamUtils.startsWith(search, buffer, start, stop); |
| 180 | } else if (!eof) { |
| 181 | // Harder path |
| 182 | if (buffer2 == null && buffer.length == originalBuffer.length) { |
| 183 | buffer2 = Arrays.copyOf(buffer, buffer.length * 2); |
| 184 | |
| 185 | pos2 = buffer.length; |
| 186 | len2 = read(in, buffer2, pos2, buffer.length); |
| 187 | if (len2 > 0) { |
| 188 | bytesRead += len2; |
| 189 | } |
| 190 | |
| 191 | // Note: here, len/len2 = INDEX of last good byte |
| 192 | len2 += pos2; |
| 193 | } |
| 194 | |
| 195 | return StreamUtils.startsWith(search, buffer2, pos2, len2); |
| 196 | } |
| 197 | |
| 198 | return false; |
| 199 | } |
| 200 | |
| 201 | /** |
| 202 | * The number of bytes read from the under-laying {@link InputStream}. |
| 203 | * |
| 204 | * @return the number of bytes |
| 205 | */ |
| 206 | public long getBytesRead() { |
| 207 | return bytesRead; |
| 208 | } |
| 209 | |
| 210 | /** |
| 211 | * Check if this stream is totally spent (no more data to read or to |
| 212 | * process). |
| 213 | * |
| 214 | * @return TRUE if it is |
| 215 | * |
| 216 | * @throws IOException |
| 217 | * in case of I/O error |
| 218 | */ |
| 219 | public boolean eof() throws IOException { |
| 220 | if (closed) { |
| 221 | return true; |
| 222 | } |
| 223 | |
| 224 | preRead(); |
| 225 | return !hasMoreData(); |
| 226 | } |
| 227 | |
| 228 | @Override |
| 229 | public int read() throws IOException { |
| 230 | checkClose(); |
| 231 | |
| 232 | preRead(); |
| 233 | if (eof) { |
| 234 | return -1; |
| 235 | } |
| 236 | |
| 237 | return buffer[start++]; |
| 238 | } |
| 239 | |
| 240 | @Override |
| 241 | public int read(byte[] b) throws IOException { |
| 242 | return read(b, 0, b.length); |
| 243 | } |
| 244 | |
| 245 | @Override |
| 246 | public int read(byte[] b, int boff, int blen) throws IOException { |
| 247 | checkClose(); |
| 248 | |
| 249 | if (b == null) { |
| 250 | throw new NullPointerException(); |
| 251 | } else if (boff < 0 || blen < 0 || blen > b.length - boff) { |
| 252 | throw new IndexOutOfBoundsException(); |
| 253 | } else if (blen == 0) { |
| 254 | return 0; |
| 255 | } |
| 256 | |
| 257 | int done = 0; |
| 258 | while (hasMoreData() && done < blen) { |
| 259 | preRead(); |
| 260 | if (hasMoreData()) { |
| 261 | int now = Math.min(blen - done, stop - start); |
| 262 | if (now > 0) { |
| 263 | System.arraycopy(buffer, start, b, boff + done, now); |
| 264 | start += now; |
| 265 | done += now; |
| 266 | } |
| 267 | } |
| 268 | } |
| 269 | |
| 270 | return done > 0 ? done : -1; |
| 271 | } |
| 272 | |
| 273 | @Override |
| 274 | public long skip(long n) throws IOException { |
| 275 | if (n <= 0) { |
| 276 | return 0; |
| 277 | } |
| 278 | |
| 279 | long skipped = 0; |
| 280 | while (hasMoreData() && n > 0) { |
| 281 | preRead(); |
| 282 | |
| 283 | long inBuffer = Math.min(n, available()); |
| 284 | start += inBuffer; |
| 285 | n -= inBuffer; |
| 286 | skipped += inBuffer; |
| 287 | } |
| 288 | |
| 289 | return skipped; |
| 290 | } |
| 291 | |
| 292 | @Override |
| 293 | public int available() { |
| 294 | if (closed) { |
| 295 | return 0; |
| 296 | } |
| 297 | |
| 298 | return Math.max(0, stop - start); |
| 299 | } |
| 300 | |
| 301 | /** |
| 302 | * Closes this stream and releases any system resources associated with the |
| 303 | * stream. |
| 304 | * <p> |
| 305 | * Including the under-laying {@link InputStream}. |
| 306 | * <p> |
| 307 | * <b>Note:</b> if you called the {@link BufferedInputStream#open()} method |
| 308 | * prior to this one, it will just decrease the internal count of how many |
| 309 | * open streams it held and do nothing else. The stream will actually be |
| 310 | * closed when you have called {@link BufferedInputStream#close()} once more |
| 311 | * than {@link BufferedInputStream#open()}. |
| 312 | * |
| 313 | * @exception IOException |
| 314 | * in case of I/O error |
| 315 | */ |
| 316 | @Override |
| 317 | public synchronized void close() throws IOException { |
| 318 | close(true); |
| 319 | } |
| 320 | |
| 321 | /** |
| 322 | * Closes this stream and releases any system resources associated with the |
| 323 | * stream. |
| 324 | * <p> |
| 325 | * Including the under-laying {@link InputStream} if |
| 326 | * <tt>incudingSubStream</tt> is true. |
| 327 | * <p> |
| 328 | * You can call this method multiple times, it will not cause an |
| 329 | * {@link IOException} for subsequent calls. |
| 330 | * <p> |
| 331 | * <b>Note:</b> if you called the {@link BufferedInputStream#open()} method |
| 332 | * prior to this one, it will just decrease the internal count of how many |
| 333 | * open streams it held and do nothing else. The stream will actually be |
| 334 | * closed when you have called {@link BufferedInputStream#close()} once more |
| 335 | * than {@link BufferedInputStream#open()}. |
| 336 | * |
| 337 | * @param includingSubStream |
| 338 | * also close the under-laying stream |
| 339 | * |
| 340 | * @exception IOException |
| 341 | * in case of I/O error |
| 342 | */ |
| 343 | public synchronized void close(boolean includingSubStream) |
| 344 | throws IOException { |
| 345 | if (!closed) { |
| 346 | if (openCounter > 0) { |
| 347 | openCounter--; |
| 348 | } else { |
| 349 | closed = true; |
| 350 | if (includingSubStream && in != null) { |
| 351 | in.close(); |
| 352 | } |
| 353 | } |
| 354 | } |
| 355 | } |
| 356 | |
| 357 | /** |
| 358 | * Check if we still have some data in the buffer and, if not, fetch some. |
| 359 | * |
| 360 | * @return TRUE if we fetched some data, FALSE if there are still some in |
| 361 | * the buffer |
| 362 | * |
| 363 | * @throws IOException |
| 364 | * in case of I/O error |
| 365 | */ |
| 366 | protected boolean preRead() throws IOException { |
| 367 | boolean hasRead = false; |
| 368 | if (in != null && !eof && start >= stop) { |
| 369 | start = 0; |
| 370 | if (buffer2 != null) { |
| 371 | buffer = buffer2; |
| 372 | start = pos2; |
| 373 | stop = len2; |
| 374 | |
| 375 | buffer2 = null; |
| 376 | pos2 = 0; |
| 377 | len2 = 0; |
| 378 | } else { |
| 379 | buffer = originalBuffer; |
| 380 | |
| 381 | stop = read(in, buffer, 0, buffer.length); |
| 382 | if (stop > 0) { |
| 383 | bytesRead += stop; |
| 384 | } |
| 385 | } |
| 386 | |
| 387 | hasRead = true; |
| 388 | } |
| 389 | |
| 390 | if (start >= stop) { |
| 391 | eof = true; |
| 392 | } |
| 393 | |
| 394 | return hasRead; |
| 395 | } |
| 396 | |
| 397 | /** |
| 398 | * Read the under-laying stream into the local buffer. |
| 399 | * |
| 400 | * @param in |
| 401 | * the under-laying {@link InputStream} |
| 402 | * @param buffer |
| 403 | * the buffer we use in this {@link BufferedInputStream} |
| 404 | * @param off |
| 405 | * the offset |
| 406 | * @param len |
| 407 | * the length in bytes |
| 408 | * |
| 409 | * @return the number of bytes read |
| 410 | * |
| 411 | * @throws IOException |
| 412 | * in case of I/O error |
| 413 | */ |
| 414 | protected int read(InputStream in, byte[] buffer, int off, int len) |
| 415 | throws IOException { |
| 416 | return in.read(buffer, off, len); |
| 417 | } |
| 418 | |
| 419 | /** |
| 420 | * We have more data available in the buffer <b>or</b> we can, maybe, fetch |
| 421 | * more. |
| 422 | * |
| 423 | * @return TRUE if it is the case, FALSE if not |
| 424 | */ |
| 425 | protected boolean hasMoreData() { |
| 426 | if (closed) { |
| 427 | return false; |
| 428 | } |
| 429 | |
| 430 | return (start < stop) || !eof; |
| 431 | } |
| 432 | |
| 433 | /** |
| 434 | * Check that the stream was not closed, and throw an {@link IOException} if |
| 435 | * it was. |
| 436 | * |
| 437 | * @throws IOException |
| 438 | * if it was closed |
| 439 | */ |
| 440 | protected void checkClose() throws IOException { |
| 441 | if (closed) { |
| 442 | throw new IOException( |
| 443 | "This BufferedInputStream was closed, you cannot use it anymore."); |
| 444 | } |
| 445 | } |
| 446 | } |