| 1 | package be.nikiroo.utils.streams; |
| 2 | |
| 3 | import java.io.IOException; |
| 4 | import java.io.InputStream; |
| 5 | import java.util.AbstractMap; |
| 6 | import java.util.ArrayList; |
| 7 | import java.util.List; |
| 8 | import java.util.Map.Entry; |
| 9 | |
| 10 | import be.nikiroo.utils.StringUtils; |
| 11 | |
| 12 | /** |
| 13 | * A simple {@link InputStream} that is buffered with a bytes array. |
| 14 | * <p> |
| 15 | * It is mostly intended to be used as a base class to create new |
| 16 | * {@link InputStream}s with special operation modes, and to give some default |
| 17 | * methods. |
| 18 | * |
| 19 | * @author niki |
| 20 | */ |
| 21 | public class BufferedInputStream extends InputStream { |
| 22 | /** |
| 23 | * The size of the internal buffer (can be different if you pass your own |
| 24 | * buffer, of course, and can also expand to search for longer "startsWith" |
| 25 | * data). |
| 26 | * <p> |
| 27 | * Note that special "push-back" buffers can also be created during the life |
| 28 | * of this stream. |
| 29 | */ |
| 30 | static private final int BUFFER_SIZE = 4096; |
| 31 | |
| 32 | /** The current position in the buffer. */ |
| 33 | protected int start; |
| 34 | /** The index of the last usable position of the buffer. */ |
| 35 | protected int stop; |
| 36 | /** The buffer itself. */ |
| 37 | protected byte[] buffer; |
| 38 | /** An End-Of-File (or {@link InputStream}, here) marker. */ |
| 39 | protected boolean eof; |
| 40 | |
| 41 | private boolean closed; |
| 42 | private InputStream in; |
| 43 | private int openCounter; |
| 44 | private byte[] singleByteReader = new byte[1]; |
| 45 | |
| 46 | /** array + offset of pushed-back buffers */ |
| 47 | private List<Entry<byte[], Integer>> backBuffers; |
| 48 | |
| 49 | private long bytesRead; |
| 50 | |
| 51 | /** |
| 52 | * Create a new {@link BufferedInputStream} that wraps the given |
| 53 | * {@link InputStream}. |
| 54 | * |
| 55 | * @param in |
| 56 | * the {@link InputStream} to wrap |
| 57 | */ |
| 58 | public BufferedInputStream(InputStream in) { |
| 59 | this.in = in; |
| 60 | |
| 61 | this.buffer = new byte[BUFFER_SIZE]; |
| 62 | this.start = 0; |
| 63 | this.stop = 0; |
| 64 | this.backBuffers = new ArrayList<Entry<byte[], Integer>>(); |
| 65 | } |
| 66 | |
| 67 | /** |
| 68 | * Create a new {@link BufferedInputStream} that wraps the given bytes array |
| 69 | * as a data source. |
| 70 | * |
| 71 | * @param in |
| 72 | * the array to wrap, cannot be NULL |
| 73 | */ |
| 74 | public BufferedInputStream(byte[] in) { |
| 75 | this(in, 0, in.length); |
| 76 | } |
| 77 | |
| 78 | /** |
| 79 | * Create a new {@link BufferedInputStream} that wraps the given bytes array |
| 80 | * as a data source. |
| 81 | * |
| 82 | * @param in |
| 83 | * the array to wrap, cannot be NULL |
| 84 | * @param offset |
| 85 | * the offset to start the reading at |
| 86 | * @param length |
| 87 | * the number of bytes to take into account in the array, |
| 88 | * starting from the offset |
| 89 | * |
| 90 | * @throws NullPointerException |
| 91 | * if the array is NULL |
| 92 | * @throws IndexOutOfBoundsException |
| 93 | * if the offset and length do not correspond to the given array |
| 94 | */ |
| 95 | public BufferedInputStream(byte[] in, int offset, int length) { |
| 96 | if (in == null) { |
| 97 | throw new NullPointerException(); |
| 98 | } else if (offset < 0 || length < 0 || length > in.length - offset) { |
| 99 | throw new IndexOutOfBoundsException(); |
| 100 | } |
| 101 | |
| 102 | this.in = null; |
| 103 | |
| 104 | this.buffer = in; |
| 105 | this.start = offset; |
| 106 | this.stop = length; |
| 107 | this.backBuffers = new ArrayList<Entry<byte[], Integer>>(); |
| 108 | } |
| 109 | |
| 110 | /** |
| 111 | * Return this very same {@link BufferedInputStream}, but keep a counter of |
| 112 | * how many streams were open this way. When calling |
| 113 | * {@link BufferedInputStream#close()}, decrease this counter if it is not |
| 114 | * already zero instead of actually closing the stream. |
| 115 | * <p> |
| 116 | * You are now responsible for it — you <b>must</b> close it. |
| 117 | * <p> |
| 118 | * This method allows you to use a wrapping stream around this one and still |
| 119 | * close the wrapping stream. |
| 120 | * |
| 121 | * @return the same stream, but you are now responsible for closing it |
| 122 | * |
| 123 | * @throws IOException |
| 124 | * in case of I/O error or if the stream is closed |
| 125 | */ |
| 126 | public synchronized InputStream open() throws IOException { |
| 127 | checkClose(); |
| 128 | openCounter++; |
| 129 | return this; |
| 130 | } |
| 131 | |
| 132 | /** |
| 133 | * Check if the current content (until eof) is equal to the given search |
| 134 | * term. |
| 135 | * <p> |
| 136 | * Note: the search term size <b>must</b> be smaller or equal the internal |
| 137 | * buffer size. |
| 138 | * |
| 139 | * @param search |
| 140 | * the term to search for |
| 141 | * |
| 142 | * @return TRUE if the content that will be read starts with it |
| 143 | * |
| 144 | * @throws IOException |
| 145 | * in case of I/O error or if the size of the search term is |
| 146 | * greater than the internal buffer |
| 147 | */ |
| 148 | public boolean is(String search) throws IOException { |
| 149 | return is(StringUtils.getBytes(search)); |
| 150 | } |
| 151 | |
| 152 | /** |
| 153 | * Check if the current content (until eof) is equal to the given search |
| 154 | * term. |
| 155 | * <p> |
| 156 | * Note: the search term size <b>must</b> be smaller or equal the internal |
| 157 | * buffer size. |
| 158 | * |
| 159 | * @param search |
| 160 | * the term to search for |
| 161 | * |
| 162 | * @return TRUE if the content that will be read starts with it |
| 163 | * |
| 164 | * @throws IOException |
| 165 | * in case of I/O error or if the size of the search term is |
| 166 | * greater than the internal buffer |
| 167 | */ |
| 168 | public boolean is(byte[] search) throws IOException { |
| 169 | if (startsWith(search)) { |
| 170 | return available() == search.length; |
| 171 | } |
| 172 | |
| 173 | return false; |
| 174 | } |
| 175 | |
| 176 | /** |
| 177 | * Check if the current content (what will be read next) starts with the |
| 178 | * given search term. |
| 179 | * <p> |
| 180 | * Note: the search term size <b>must</b> be smaller or equal the internal |
| 181 | * buffer size. |
| 182 | * |
| 183 | * @param search |
| 184 | * the term to search for |
| 185 | * |
| 186 | * @return TRUE if the content that will be read starts with it |
| 187 | * |
| 188 | * @throws IOException |
| 189 | * in case of I/O error or if the size of the search term is |
| 190 | * greater than the internal buffer |
| 191 | */ |
| 192 | public boolean startsWith(String search) throws IOException { |
| 193 | return startsWith(StringUtils.getBytes(search)); |
| 194 | } |
| 195 | |
| 196 | /** |
| 197 | * Check if the current content (what will be read next) starts with the |
| 198 | * given search term. |
| 199 | * <p> |
| 200 | * An empty string will always return true (unless the stream is closed, |
| 201 | * which would throw an {@link IOException}). |
| 202 | * <p> |
| 203 | * Note: the search term size <b>must</b> be smaller or equal the internal |
| 204 | * buffer size. |
| 205 | * |
| 206 | * @param search |
| 207 | * the term to search for |
| 208 | * |
| 209 | * @return TRUE if the content that will be read starts with it |
| 210 | * |
| 211 | * @throws IOException |
| 212 | * in case of I/O error or if the size of the search term is |
| 213 | * greater than the internal buffer |
| 214 | */ |
| 215 | public boolean startsWith(byte[] search) throws IOException { |
| 216 | checkClose(); |
| 217 | |
| 218 | while (consolidatePushBack(search.length) < search.length) { |
| 219 | preRead(); |
| 220 | if (start >= stop) { |
| 221 | // Not enough data left to start with that |
| 222 | return false; |
| 223 | } |
| 224 | |
| 225 | byte[] newBuffer = new byte[stop - start]; |
| 226 | System.arraycopy(buffer, start, newBuffer, 0, stop - start); |
| 227 | pushback(newBuffer, 0); |
| 228 | start = stop; |
| 229 | } |
| 230 | |
| 231 | Entry<byte[], Integer> bb = backBuffers.get(backBuffers.size() - 1); |
| 232 | byte[] bbBuffer = bb.getKey(); |
| 233 | int bbOffset = bb.getValue(); |
| 234 | |
| 235 | return StreamUtils.startsWith(search, bbBuffer, bbOffset, |
| 236 | bbBuffer.length); |
| 237 | } |
| 238 | |
| 239 | /** |
| 240 | * The number of bytes read from the under-laying {@link InputStream}. |
| 241 | * |
| 242 | * @return the number of bytes |
| 243 | */ |
| 244 | public long getBytesRead() { |
| 245 | return bytesRead; |
| 246 | } |
| 247 | |
| 248 | /** |
| 249 | * Check if this stream is spent (no more data to read or to process). |
| 250 | * |
| 251 | * @return TRUE if it is |
| 252 | * |
| 253 | * @throws IOException |
| 254 | * in case of I/O error |
| 255 | */ |
| 256 | public boolean eof() throws IOException { |
| 257 | if (closed) { |
| 258 | return true; |
| 259 | } |
| 260 | |
| 261 | preRead(); |
| 262 | return !hasMoreData(); |
| 263 | } |
| 264 | |
| 265 | /** |
| 266 | * Read the whole {@link InputStream} until the end and return the number of |
| 267 | * bytes read. |
| 268 | * |
| 269 | * @return the number of bytes read |
| 270 | * |
| 271 | * @throws IOException |
| 272 | * in case of I/O error |
| 273 | */ |
| 274 | public long end() throws IOException { |
| 275 | long skipped = 0; |
| 276 | while (hasMoreData()) { |
| 277 | skipped += skip(buffer.length); |
| 278 | } |
| 279 | |
| 280 | return skipped; |
| 281 | } |
| 282 | |
| 283 | @Override |
| 284 | public int read() throws IOException { |
| 285 | if (read(singleByteReader) < 0) { |
| 286 | return -1; |
| 287 | } |
| 288 | |
| 289 | return singleByteReader[0]; |
| 290 | } |
| 291 | |
| 292 | @Override |
| 293 | public int read(byte[] b) throws IOException { |
| 294 | return read(b, 0, b.length); |
| 295 | } |
| 296 | |
| 297 | @Override |
| 298 | public int read(byte[] b, int boff, int blen) throws IOException { |
| 299 | checkClose(); |
| 300 | |
| 301 | if (b == null) { |
| 302 | throw new NullPointerException(); |
| 303 | } else if (boff < 0 || blen < 0 || blen > b.length - boff) { |
| 304 | throw new IndexOutOfBoundsException(); |
| 305 | } else if (blen == 0) { |
| 306 | return 0; |
| 307 | } |
| 308 | |
| 309 | // Read from the pushed-back buffers if any |
| 310 | if (backBuffers.isEmpty()) { |
| 311 | preRead(); // an implementation could pushback in preRead() |
| 312 | } |
| 313 | |
| 314 | if (!backBuffers.isEmpty()) { |
| 315 | int read = 0; |
| 316 | |
| 317 | Entry<byte[], Integer> bb = backBuffers |
| 318 | .remove(backBuffers.size() - 1); |
| 319 | byte[] bbBuffer = bb.getKey(); |
| 320 | int bbOffset = bb.getValue(); |
| 321 | int bbSize = bbBuffer.length - bbOffset; |
| 322 | |
| 323 | if (bbSize > blen) { |
| 324 | read = blen; |
| 325 | System.arraycopy(bbBuffer, bbOffset, b, boff, read); |
| 326 | pushback(bbBuffer, bbOffset + read); |
| 327 | } else { |
| 328 | read = bbSize; |
| 329 | System.arraycopy(bbBuffer, bbOffset, b, boff, read); |
| 330 | } |
| 331 | |
| 332 | return read; |
| 333 | } |
| 334 | |
| 335 | int done = 0; |
| 336 | while (hasMoreData() && done < blen) { |
| 337 | preRead(); |
| 338 | if (hasMoreData()) { |
| 339 | int now = Math.min(blen - done, stop - start); |
| 340 | if (now > 0) { |
| 341 | System.arraycopy(buffer, start, b, boff + done, now); |
| 342 | start += now; |
| 343 | done += now; |
| 344 | } |
| 345 | } |
| 346 | } |
| 347 | |
| 348 | return done > 0 ? done : -1; |
| 349 | } |
| 350 | |
| 351 | @Override |
| 352 | public long skip(long n) throws IOException { |
| 353 | if (n <= 0) { |
| 354 | return 0; |
| 355 | } |
| 356 | |
| 357 | long skipped = 0; |
| 358 | while (!backBuffers.isEmpty() && n > 0) { |
| 359 | Entry<byte[], Integer> bb = backBuffers |
| 360 | .remove(backBuffers.size() - 1); |
| 361 | byte[] bbBuffer = bb.getKey(); |
| 362 | int bbOffset = bb.getValue(); |
| 363 | int bbSize = bbBuffer.length - bbOffset; |
| 364 | |
| 365 | int localSkip = 0; |
| 366 | localSkip = (int) Math.min(n, bbSize); |
| 367 | |
| 368 | n -= localSkip; |
| 369 | bbSize -= localSkip; |
| 370 | |
| 371 | if (bbSize > 0) { |
| 372 | pushback(bbBuffer, bbOffset + localSkip); |
| 373 | } |
| 374 | } |
| 375 | while (hasMoreData() && n > 0) { |
| 376 | preRead(); |
| 377 | |
| 378 | long inBuffer = Math.min(n, available()); |
| 379 | start += inBuffer; |
| 380 | n -= inBuffer; |
| 381 | skipped += inBuffer; |
| 382 | } |
| 383 | |
| 384 | return skipped; |
| 385 | } |
| 386 | |
| 387 | @Override |
| 388 | public int available() { |
| 389 | if (closed) { |
| 390 | return 0; |
| 391 | } |
| 392 | |
| 393 | int avail = 0; |
| 394 | for (Entry<byte[], Integer> entry : backBuffers) { |
| 395 | avail += entry.getKey().length - entry.getValue(); |
| 396 | } |
| 397 | |
| 398 | return avail + Math.max(0, stop - start); |
| 399 | } |
| 400 | |
| 401 | /** |
| 402 | * Closes this stream and releases any system resources associated with the |
| 403 | * stream. |
| 404 | * <p> |
| 405 | * Including the under-laying {@link InputStream}. |
| 406 | * <p> |
| 407 | * <b>Note:</b> if you called the {@link BufferedInputStream#open()} method |
| 408 | * prior to this one, it will just decrease the internal count of how many |
| 409 | * open streams it held and do nothing else. The stream will actually be |
| 410 | * closed when you have called {@link BufferedInputStream#close()} once more |
| 411 | * than {@link BufferedInputStream#open()}. |
| 412 | * |
| 413 | * @exception IOException |
| 414 | * in case of I/O error |
| 415 | */ |
| 416 | @Override |
| 417 | public synchronized void close() throws IOException { |
| 418 | close(true); |
| 419 | } |
| 420 | |
| 421 | /** |
| 422 | * Closes this stream and releases any system resources associated with the |
| 423 | * stream. |
| 424 | * <p> |
| 425 | * Including the under-laying {@link InputStream} if |
| 426 | * <tt>incudingSubStream</tt> is true. |
| 427 | * <p> |
| 428 | * You can call this method multiple times, it will not cause an |
| 429 | * {@link IOException} for subsequent calls. |
| 430 | * <p> |
| 431 | * <b>Note:</b> if you called the {@link BufferedInputStream#open()} method |
| 432 | * prior to this one, it will just decrease the internal count of how many |
| 433 | * open streams it held and do nothing else. The stream will actually be |
| 434 | * closed when you have called {@link BufferedInputStream#close()} once more |
| 435 | * than {@link BufferedInputStream#open()}. |
| 436 | * |
| 437 | * @param includingSubStream |
| 438 | * also close the under-laying stream |
| 439 | * |
| 440 | * @exception IOException |
| 441 | * in case of I/O error |
| 442 | */ |
| 443 | public synchronized void close(boolean includingSubStream) |
| 444 | throws IOException { |
| 445 | if (!closed) { |
| 446 | if (openCounter > 0) { |
| 447 | openCounter--; |
| 448 | } else { |
| 449 | closed = true; |
| 450 | if (includingSubStream && in != null) { |
| 451 | in.close(); |
| 452 | } |
| 453 | } |
| 454 | } |
| 455 | } |
| 456 | |
| 457 | /** |
| 458 | * Consolidate the push-back buffers so the last one is at least the given |
| 459 | * size, if possible. |
| 460 | * <p> |
| 461 | * If there is not enough data in the push-back buffers, they will all be |
| 462 | * consolidated. |
| 463 | * |
| 464 | * @param size |
| 465 | * the minimum size of the consolidated buffer, or -1 to force |
| 466 | * the consolidation of all push-back buffers |
| 467 | * |
| 468 | * @return the size of the last, consolidated buffer; can be less than the |
| 469 | * requested size if not enough data |
| 470 | */ |
| 471 | protected int consolidatePushBack(int size) { |
| 472 | int bbIndex = -1; |
| 473 | int bbUpToSize = 0; |
| 474 | for (Entry<byte[], Integer> entry : backBuffers) { |
| 475 | bbIndex++; |
| 476 | bbUpToSize += entry.getKey().length - entry.getValue(); |
| 477 | |
| 478 | if (size >= 0 && bbUpToSize >= size) { |
| 479 | break; |
| 480 | } |
| 481 | } |
| 482 | |
| 483 | // Index 0 means "the last buffer is already big enough" |
| 484 | if (bbIndex > 0) { |
| 485 | byte[] consolidatedBuffer = new byte[bbUpToSize]; |
| 486 | int consolidatedPos = 0; |
| 487 | for (int i = 0; i <= bbIndex; i++) { |
| 488 | Entry<byte[], Integer> bb = backBuffers |
| 489 | .remove(backBuffers.size() - 1); |
| 490 | byte[] bbBuffer = bb.getKey(); |
| 491 | int bbOffset = bb.getValue(); |
| 492 | int bbSize = bbBuffer.length - bbOffset; |
| 493 | System.arraycopy(bbBuffer, bbOffset, consolidatedBuffer, |
| 494 | consolidatedPos, bbSize); |
| 495 | } |
| 496 | |
| 497 | pushback(consolidatedBuffer, 0); |
| 498 | } |
| 499 | |
| 500 | return bbUpToSize; |
| 501 | } |
| 502 | |
| 503 | /** |
| 504 | * Check if we still have some data in the buffer and, if not, fetch some. |
| 505 | * |
| 506 | * @return TRUE if we fetched some data, FALSE if there are still some in |
| 507 | * the buffer |
| 508 | * |
| 509 | * @throws IOException |
| 510 | * in case of I/O error |
| 511 | */ |
| 512 | protected boolean preRead() throws IOException { |
| 513 | boolean hasRead = false; |
| 514 | if (in != null && !eof && start >= stop) { |
| 515 | start = 0; |
| 516 | stop = read(in, buffer); |
| 517 | if (stop > 0) { |
| 518 | bytesRead += stop; |
| 519 | } |
| 520 | |
| 521 | hasRead = true; |
| 522 | } |
| 523 | |
| 524 | if (start >= stop) { |
| 525 | eof = true; |
| 526 | } |
| 527 | |
| 528 | return hasRead; |
| 529 | } |
| 530 | |
| 531 | /** |
| 532 | * Push back some data that will be read again at the next read call. |
| 533 | * |
| 534 | * @param buffer |
| 535 | * the buffer to push back |
| 536 | * @param offset |
| 537 | * the offset at which to start reading in the buffer |
| 538 | */ |
| 539 | protected void pushback(byte[] buffer, int offset) { |
| 540 | backBuffers.add( |
| 541 | new AbstractMap.SimpleEntry<byte[], Integer>(buffer, offset)); |
| 542 | } |
| 543 | |
| 544 | /** |
| 545 | * Push back some data that will be read again at the next read call. |
| 546 | * |
| 547 | * @param buffer |
| 548 | * the buffer to push back |
| 549 | * @param offset |
| 550 | * the offset at which to start reading in the buffer |
| 551 | * @param len |
| 552 | * the length to copy |
| 553 | */ |
| 554 | protected void pushback(byte[] buffer, int offset, int len) { |
| 555 | // TODO: not efficient! |
| 556 | if (buffer.length != len) { |
| 557 | byte[] lenNotSupportedYet = new byte[len]; |
| 558 | System.arraycopy(buffer, offset, lenNotSupportedYet, 0, len); |
| 559 | buffer = lenNotSupportedYet; |
| 560 | offset = 0; |
| 561 | } |
| 562 | |
| 563 | pushback(buffer, offset); |
| 564 | } |
| 565 | |
| 566 | /** |
| 567 | * Read the under-laying stream into the given local buffer. |
| 568 | * |
| 569 | * @param in |
| 570 | * the under-laying {@link InputStream} |
| 571 | * @param buffer |
| 572 | * the buffer we use in this {@link BufferedInputStream} |
| 573 | * |
| 574 | * @return the number of bytes read |
| 575 | * |
| 576 | * @throws IOException |
| 577 | * in case of I/O error |
| 578 | */ |
| 579 | protected int read(InputStream in, byte[] buffer) throws IOException { |
| 580 | return in.read(buffer, 0, buffer.length); |
| 581 | } |
| 582 | |
| 583 | /** |
| 584 | * We have more data available in the buffer <b>or</b> we can, maybe, fetch |
| 585 | * more. |
| 586 | * |
| 587 | * @return TRUE if it is the case, FALSE if not |
| 588 | */ |
| 589 | protected boolean hasMoreData() { |
| 590 | if (closed) { |
| 591 | return false; |
| 592 | } |
| 593 | |
| 594 | return !backBuffers.isEmpty() || (start < stop) || !eof; |
| 595 | } |
| 596 | |
| 597 | /** |
| 598 | * Check that the stream was not closed, and throw an {@link IOException} if |
| 599 | * it was. |
| 600 | * |
| 601 | * @throws IOException |
| 602 | * if it was closed |
| 603 | */ |
| 604 | protected void checkClose() throws IOException { |
| 605 | if (closed) { |
| 606 | throw new IOException( |
| 607 | "This BufferedInputStream was closed, you cannot use it anymore."); |
| 608 | } |
| 609 | } |
| 610 | } |