1 /* 2 * Copyright (c) 1994, 2016, 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.io; 27 28 import java.nio.ByteOrder; 29 import libcore.io.Memory; 30 31 /** 32 * A data input stream lets an application read primitive Java data 33 * types from an underlying input stream in a machine-independent 34 * way. An application uses a data output stream to write data that 35 * can later be read by a data input stream. 36 * <p> 37 * DataInputStream is not necessarily safe for multithreaded access. 38 * Thread safety is optional and is the responsibility of users of 39 * methods in this class. 40 * 41 * @author Arthur van Hoff 42 * @see java.io.DataOutputStream 43 * @since 1.0 44 */ 45 public 46 class DataInputStream extends FilterInputStream implements DataInput { 47 48 /** 49 * Creates a DataInputStream that uses the specified 50 * underlying InputStream. 51 * 52 * @param in the specified input stream 53 */ DataInputStream(InputStream in)54 public DataInputStream(InputStream in) { 55 super(in); 56 } 57 58 /** 59 * working arrays initialized on demand by readUTF 60 */ 61 private byte bytearr[] = new byte[80]; 62 private char chararr[] = new char[80]; 63 64 /** 65 * Reads some number of bytes from the contained input stream and 66 * stores them into the buffer array <code>b</code>. The number of 67 * bytes actually read is returned as an integer. This method blocks 68 * until input data is available, end of file is detected, or an 69 * exception is thrown. 70 * 71 * <p>If <code>b</code> is null, a <code>NullPointerException</code> is 72 * thrown. If the length of <code>b</code> is zero, then no bytes are 73 * read and <code>0</code> is returned; otherwise, there is an attempt 74 * to read at least one byte. If no byte is available because the 75 * stream is at end of file, the value <code>-1</code> is returned; 76 * otherwise, at least one byte is read and stored into <code>b</code>. 77 * 78 * <p>The first byte read is stored into element <code>b[0]</code>, the 79 * next one into <code>b[1]</code>, and so on. The number of bytes read 80 * is, at most, equal to the length of <code>b</code>. Let <code>k</code> 81 * be the number of bytes actually read; these bytes will be stored in 82 * elements <code>b[0]</code> through <code>b[k-1]</code>, leaving 83 * elements <code>b[k]</code> through <code>b[b.length-1]</code> 84 * unaffected. 85 * 86 * <p>The <code>read(b)</code> method has the same effect as: 87 * <blockquote><pre> 88 * read(b, 0, b.length) 89 * </pre></blockquote> 90 * 91 * @param b the buffer into which the data is read. 92 * @return the total number of bytes read into the buffer, or 93 * <code>-1</code> if there is no more data because the end 94 * of the stream has been reached. 95 * @exception IOException if the first byte cannot be read for any reason 96 * other than end of file, the stream has been closed and the underlying 97 * input stream does not support reading after close, or another I/O 98 * error occurs. 99 * @see java.io.FilterInputStream#in 100 * @see java.io.InputStream#read(byte[], int, int) 101 */ read(byte b[])102 public final int read(byte b[]) throws IOException { 103 return in.read(b, 0, b.length); 104 } 105 106 /** 107 * Reads up to <code>len</code> bytes of data from the contained 108 * input stream into an array of bytes. An attempt is made to read 109 * as many as <code>len</code> bytes, but a smaller number may be read, 110 * possibly zero. The number of bytes actually read is returned as an 111 * integer. 112 * 113 * <p> This method blocks until input data is available, end of file is 114 * detected, or an exception is thrown. 115 * 116 * <p> If <code>len</code> is zero, then no bytes are read and 117 * <code>0</code> is returned; otherwise, there is an attempt to read at 118 * least one byte. If no byte is available because the stream is at end of 119 * file, the value <code>-1</code> is returned; otherwise, at least one 120 * byte is read and stored into <code>b</code>. 121 * 122 * <p> The first byte read is stored into element <code>b[off]</code>, the 123 * next one into <code>b[off+1]</code>, and so on. The number of bytes read 124 * is, at most, equal to <code>len</code>. Let <i>k</i> be the number of 125 * bytes actually read; these bytes will be stored in elements 126 * <code>b[off]</code> through <code>b[off+</code><i>k</i><code>-1]</code>, 127 * leaving elements <code>b[off+</code><i>k</i><code>]</code> through 128 * <code>b[off+len-1]</code> unaffected. 129 * 130 * <p> In every case, elements <code>b[0]</code> through 131 * <code>b[off]</code> and elements <code>b[off+len]</code> through 132 * <code>b[b.length-1]</code> are unaffected. 133 * 134 * @param b the buffer into which the data is read. 135 * @param off the start offset in the destination array <code>b</code> 136 * @param len the maximum number of bytes read. 137 * @return the total number of bytes read into the buffer, or 138 * <code>-1</code> if there is no more data because the end 139 * of the stream has been reached. 140 * @exception NullPointerException If <code>b</code> is <code>null</code>. 141 * @exception IndexOutOfBoundsException If <code>off</code> is negative, 142 * <code>len</code> is negative, or <code>len</code> is greater than 143 * <code>b.length - off</code> 144 * @exception IOException if the first byte cannot be read for any reason 145 * other than end of file, the stream has been closed and the underlying 146 * input stream does not support reading after close, or another I/O 147 * error occurs. 148 * @see java.io.FilterInputStream#in 149 * @see java.io.InputStream#read(byte[], int, int) 150 */ read(byte b[], int off, int len)151 public final int read(byte b[], int off, int len) throws IOException { 152 return in.read(b, off, len); 153 } 154 155 /** 156 * See the general contract of the {@code readFully} 157 * method of {@code DataInput}. 158 * <p> 159 * Bytes 160 * for this operation are read from the contained 161 * input stream. 162 * 163 * @param b the buffer into which the data is read. 164 * @throws NullPointerException if {@code b} is {@code null}. 165 * @throws EOFException if this input stream reaches the end before 166 * reading all the bytes. 167 * @throws IOException the stream has been closed and the contained 168 * input stream does not support reading after close, or 169 * another I/O error occurs. 170 * @see java.io.FilterInputStream#in 171 */ readFully(byte b[])172 public final void readFully(byte b[]) throws IOException { 173 readFully(b, 0, b.length); 174 } 175 176 /** 177 * See the general contract of the {@code readFully} 178 * method of {@code DataInput}. 179 * <p> 180 * Bytes 181 * for this operation are read from the contained 182 * input stream. 183 * 184 * @param b the buffer into which the data is read. 185 * @param off the start offset in the data array {@code b}. 186 * @param len the number of bytes to read. 187 * @exception NullPointerException if {@code b} is {@code null}. 188 * @exception IndexOutOfBoundsException if {@code off} is negative, 189 * {@code len} is negative, or {@code len} is greater than 190 * {@code b.length - off}. 191 * @exception EOFException if this input stream reaches the end before 192 * reading all the bytes. 193 * @exception IOException the stream has been closed and the contained 194 * input stream does not support reading after close, or 195 * another I/O error occurs. 196 * @see java.io.FilterInputStream#in 197 */ readFully(byte b[], int off, int len)198 public final void readFully(byte b[], int off, int len) throws IOException { 199 if (len < 0) 200 throw new IndexOutOfBoundsException(); 201 int n = 0; 202 while (n < len) { 203 int count = in.read(b, off + n, len - n); 204 if (count < 0) 205 throw new EOFException(); 206 n += count; 207 } 208 } 209 210 /** 211 * See the general contract of the <code>skipBytes</code> 212 * method of <code>DataInput</code>. 213 * <p> 214 * Bytes for this operation are read from the contained 215 * input stream. 216 * 217 * @param n the number of bytes to be skipped. 218 * @return the actual number of bytes skipped. 219 * @exception IOException if the contained input stream does not support 220 * seek, or the stream has been closed and 221 * the contained input stream does not support 222 * reading after close, or another I/O error occurs. 223 */ skipBytes(int n)224 public final int skipBytes(int n) throws IOException { 225 int total = 0; 226 int cur = 0; 227 228 while ((total<n) && ((cur = (int) in.skip(n-total)) > 0)) { 229 total += cur; 230 } 231 232 return total; 233 } 234 235 /** 236 * See the general contract of the <code>readBoolean</code> 237 * method of <code>DataInput</code>. 238 * <p> 239 * Bytes for this operation are read from the contained 240 * input stream. 241 * 242 * @return the <code>boolean</code> value read. 243 * @exception EOFException if this input stream has reached the end. 244 * @exception IOException the stream has been closed and the contained 245 * input stream does not support reading after close, or 246 * another I/O error occurs. 247 * @see java.io.FilterInputStream#in 248 */ readBoolean()249 public final boolean readBoolean() throws IOException { 250 int ch = in.read(); 251 if (ch < 0) 252 throw new EOFException(); 253 return (ch != 0); 254 } 255 256 /** 257 * See the general contract of the <code>readByte</code> 258 * method of <code>DataInput</code>. 259 * <p> 260 * Bytes 261 * for this operation are read from the contained 262 * input stream. 263 * 264 * @return the next byte of this input stream as a signed 8-bit 265 * <code>byte</code>. 266 * @exception EOFException if this input stream has reached the end. 267 * @exception IOException the stream has been closed and the contained 268 * input stream does not support reading after close, or 269 * another I/O error occurs. 270 * @see java.io.FilterInputStream#in 271 */ readByte()272 public final byte readByte() throws IOException { 273 int ch = in.read(); 274 if (ch < 0) 275 throw new EOFException(); 276 return (byte)(ch); 277 } 278 279 /** 280 * See the general contract of the <code>readUnsignedByte</code> 281 * method of <code>DataInput</code>. 282 * <p> 283 * Bytes 284 * for this operation are read from the contained 285 * input stream. 286 * 287 * @return the next byte of this input stream, interpreted as an 288 * unsigned 8-bit number. 289 * @exception EOFException if this input stream has reached the end. 290 * @exception IOException the stream has been closed and the contained 291 * input stream does not support reading after close, or 292 * another I/O error occurs. 293 * @see java.io.FilterInputStream#in 294 */ readUnsignedByte()295 public final int readUnsignedByte() throws IOException { 296 int ch = in.read(); 297 if (ch < 0) 298 throw new EOFException(); 299 return ch; 300 } 301 302 /** 303 * See the general contract of the <code>readShort</code> 304 * method of <code>DataInput</code>. 305 * <p> 306 * Bytes 307 * for this operation are read from the contained 308 * input stream. 309 * 310 * @return the next two bytes of this input stream, interpreted as a 311 * signed 16-bit number. 312 * @exception EOFException if this input stream reaches the end before 313 * reading two bytes. 314 * @exception IOException the stream has been closed and the contained 315 * input stream does not support reading after close, or 316 * another I/O error occurs. 317 * @see java.io.FilterInputStream#in 318 */ readShort()319 public final short readShort() throws IOException { 320 // b/30268192 321 // Android-changed: Use read(byte[], int, int) instead of read(). 322 readFully(readBuffer, 0, 2); 323 return Memory.peekShort(readBuffer, 0, ByteOrder.BIG_ENDIAN); 324 } 325 326 /** 327 * See the general contract of the <code>readUnsignedShort</code> 328 * method of <code>DataInput</code>. 329 * <p> 330 * Bytes 331 * for this operation are read from the contained 332 * input stream. 333 * 334 * @return the next two bytes of this input stream, interpreted as an 335 * unsigned 16-bit integer. 336 * @exception EOFException if this input stream reaches the end before 337 * reading two bytes. 338 * @exception IOException the stream has been closed and the contained 339 * input stream does not support reading after close, or 340 * another I/O error occurs. 341 * @see java.io.FilterInputStream#in 342 */ readUnsignedShort()343 public final int readUnsignedShort() throws IOException { 344 // b/30268192 345 // Android-changed: Use read(byte[], int, int) instead of read(). 346 readFully(readBuffer, 0, 2); 347 return Memory.peekShort(readBuffer, 0, ByteOrder.BIG_ENDIAN) & 0xffff; 348 } 349 350 /** 351 * See the general contract of the <code>readChar</code> 352 * method of <code>DataInput</code>. 353 * <p> 354 * Bytes 355 * for this operation are read from the contained 356 * input stream. 357 * 358 * @return the next two bytes of this input stream, interpreted as a 359 * <code>char</code>. 360 * @exception EOFException if this input stream reaches the end before 361 * reading two bytes. 362 * @exception IOException the stream has been closed and the contained 363 * input stream does not support reading after close, or 364 * another I/O error occurs. 365 * @see java.io.FilterInputStream#in 366 */ readChar()367 public final char readChar() throws IOException { 368 // b/30268192 369 // Android-changed: Use read(byte[], int, int) instead of read(). 370 readFully(readBuffer, 0, 2); 371 return (char)Memory.peekShort(readBuffer, 0, ByteOrder.BIG_ENDIAN); 372 } 373 374 /** 375 * See the general contract of the <code>readInt</code> 376 * method of <code>DataInput</code>. 377 * <p> 378 * Bytes 379 * for this operation are read from the contained 380 * input stream. 381 * 382 * @return the next four bytes of this input stream, interpreted as an 383 * <code>int</code>. 384 * @exception EOFException if this input stream reaches the end before 385 * reading four bytes. 386 * @exception IOException the stream has been closed and the contained 387 * input stream does not support reading after close, or 388 * another I/O error occurs. 389 * @see java.io.FilterInputStream#in 390 */ readInt()391 public final int readInt() throws IOException { 392 // b/30268192 393 // Android-changed: Use read(byte[], int, int) instead of read(). 394 readFully(readBuffer, 0, 4); 395 return Memory.peekInt(readBuffer, 0, ByteOrder.BIG_ENDIAN); 396 } 397 398 private byte readBuffer[] = new byte[8]; 399 400 /** 401 * See the general contract of the <code>readLong</code> 402 * method of <code>DataInput</code>. 403 * <p> 404 * Bytes 405 * for this operation are read from the contained 406 * input stream. 407 * 408 * @return the next eight bytes of this input stream, interpreted as a 409 * <code>long</code>. 410 * @exception EOFException if this input stream reaches the end before 411 * reading eight bytes. 412 * @exception IOException the stream has been closed and the contained 413 * input stream does not support reading after close, or 414 * another I/O error occurs. 415 * @see java.io.FilterInputStream#in 416 */ readLong()417 public final long readLong() throws IOException { 418 readFully(readBuffer, 0, 8); 419 return (((long)readBuffer[0] << 56) + 420 ((long)(readBuffer[1] & 255) << 48) + 421 ((long)(readBuffer[2] & 255) << 40) + 422 ((long)(readBuffer[3] & 255) << 32) + 423 ((long)(readBuffer[4] & 255) << 24) + 424 ((readBuffer[5] & 255) << 16) + 425 ((readBuffer[6] & 255) << 8) + 426 ((readBuffer[7] & 255) << 0)); 427 } 428 429 /** 430 * See the general contract of the <code>readFloat</code> 431 * method of <code>DataInput</code>. 432 * <p> 433 * Bytes 434 * for this operation are read from the contained 435 * input stream. 436 * 437 * @return the next four bytes of this input stream, interpreted as a 438 * <code>float</code>. 439 * @exception EOFException if this input stream reaches the end before 440 * reading four bytes. 441 * @exception IOException the stream has been closed and the contained 442 * input stream does not support reading after close, or 443 * another I/O error occurs. 444 * @see java.io.DataInputStream#readInt() 445 * @see java.lang.Float#intBitsToFloat(int) 446 */ readFloat()447 public final float readFloat() throws IOException { 448 return Float.intBitsToFloat(readInt()); 449 } 450 451 /** 452 * See the general contract of the <code>readDouble</code> 453 * method of <code>DataInput</code>. 454 * <p> 455 * Bytes 456 * for this operation are read from the contained 457 * input stream. 458 * 459 * @return the next eight bytes of this input stream, interpreted as a 460 * <code>double</code>. 461 * @exception EOFException if this input stream reaches the end before 462 * reading eight bytes. 463 * @exception IOException the stream has been closed and the contained 464 * input stream does not support reading after close, or 465 * another I/O error occurs. 466 * @see java.io.DataInputStream#readLong() 467 * @see java.lang.Double#longBitsToDouble(long) 468 */ readDouble()469 public final double readDouble() throws IOException { 470 return Double.longBitsToDouble(readLong()); 471 } 472 473 private char lineBuffer[]; 474 475 /** 476 * See the general contract of the <code>readLine</code> 477 * method of <code>DataInput</code>. 478 * <p> 479 * Bytes 480 * for this operation are read from the contained 481 * input stream. 482 * 483 * @deprecated This method does not properly convert bytes to characters. 484 * As of JDK 1.1, the preferred way to read lines of text is via the 485 * <code>BufferedReader.readLine()</code> method. Programs that use the 486 * <code>DataInputStream</code> class to read lines can be converted to use 487 * the <code>BufferedReader</code> class by replacing code of the form: 488 * <blockquote><pre> 489 * DataInputStream d = new DataInputStream(in); 490 * </pre></blockquote> 491 * with: 492 * <blockquote><pre> 493 * BufferedReader d 494 * = new BufferedReader(new InputStreamReader(in)); 495 * </pre></blockquote> 496 * 497 * @return the next line of text from this input stream. 498 * @exception IOException if an I/O error occurs. 499 * @see java.io.BufferedReader#readLine() 500 * @see java.io.FilterInputStream#in 501 */ 502 @Deprecated readLine()503 public final String readLine() throws IOException { 504 char buf[] = lineBuffer; 505 506 if (buf == null) { 507 buf = lineBuffer = new char[128]; 508 } 509 510 int room = buf.length; 511 int offset = 0; 512 int c; 513 514 loop: while (true) { 515 switch (c = in.read()) { 516 case -1: 517 case '\n': 518 break loop; 519 520 case '\r': 521 int c2 = in.read(); 522 if ((c2 != '\n') && (c2 != -1)) { 523 if (!(in instanceof PushbackInputStream)) { 524 this.in = new PushbackInputStream(in); 525 } 526 ((PushbackInputStream)in).unread(c2); 527 } 528 break loop; 529 530 default: 531 if (--room < 0) { 532 buf = new char[offset + 128]; 533 room = buf.length - offset - 1; 534 System.arraycopy(lineBuffer, 0, buf, 0, offset); 535 lineBuffer = buf; 536 } 537 buf[offset++] = (char) c; 538 break; 539 } 540 } 541 if ((c == -1) && (offset == 0)) { 542 return null; 543 } 544 return String.copyValueOf(buf, 0, offset); 545 } 546 547 /** 548 * See the general contract of the <code>readUTF</code> 549 * method of <code>DataInput</code>. 550 * <p> 551 * Bytes 552 * for this operation are read from the contained 553 * input stream. 554 * 555 * @return a Unicode string. 556 * @exception EOFException if this input stream reaches the end before 557 * reading all the bytes. 558 * @exception IOException the stream has been closed and the contained 559 * input stream does not support reading after close, or 560 * another I/O error occurs. 561 * @exception UTFDataFormatException if the bytes do not represent a valid 562 * modified UTF-8 encoding of a string. 563 * @see java.io.DataInputStream#readUTF(java.io.DataInput) 564 */ readUTF()565 public final String readUTF() throws IOException { 566 return readUTF(this); 567 } 568 569 /** 570 * Reads from the 571 * stream <code>in</code> a representation 572 * of a Unicode character string encoded in 573 * <a href="DataInput.html#modified-utf-8">modified UTF-8</a> format; 574 * this string of characters is then returned as a <code>String</code>. 575 * The details of the modified UTF-8 representation 576 * are exactly the same as for the <code>readUTF</code> 577 * method of <code>DataInput</code>. 578 * 579 * @param in a data input stream. 580 * @return a Unicode string. 581 * @exception EOFException if the input stream reaches the end 582 * before all the bytes. 583 * @exception IOException the stream has been closed and the contained 584 * input stream does not support reading after close, or 585 * another I/O error occurs. 586 * @exception UTFDataFormatException if the bytes do not represent a 587 * valid modified UTF-8 encoding of a Unicode string. 588 * @see java.io.DataInputStream#readUnsignedShort() 589 */ readUTF(DataInput in)590 public static final String readUTF(DataInput in) throws IOException { 591 int utflen = in.readUnsignedShort(); 592 byte[] bytearr = null; 593 char[] chararr = null; 594 if (in instanceof DataInputStream) { 595 DataInputStream dis = (DataInputStream)in; 596 if (dis.bytearr.length < utflen){ 597 dis.bytearr = new byte[utflen*2]; 598 dis.chararr = new char[utflen*2]; 599 } 600 chararr = dis.chararr; 601 bytearr = dis.bytearr; 602 } else { 603 bytearr = new byte[utflen]; 604 chararr = new char[utflen]; 605 } 606 607 int c, char2, char3; 608 int count = 0; 609 int chararr_count=0; 610 611 in.readFully(bytearr, 0, utflen); 612 613 while (count < utflen) { 614 c = (int) bytearr[count] & 0xff; 615 if (c > 127) break; 616 count++; 617 chararr[chararr_count++]=(char)c; 618 } 619 620 while (count < utflen) { 621 c = (int) bytearr[count] & 0xff; 622 switch (c >> 4) { 623 case 0: case 1: case 2: case 3: case 4: case 5: case 6: case 7: 624 /* 0xxxxxxx*/ 625 count++; 626 chararr[chararr_count++]=(char)c; 627 break; 628 case 12: case 13: 629 /* 110x xxxx 10xx xxxx*/ 630 count += 2; 631 if (count > utflen) 632 throw new UTFDataFormatException( 633 "malformed input: partial character at end"); 634 char2 = (int) bytearr[count-1]; 635 if ((char2 & 0xC0) != 0x80) 636 throw new UTFDataFormatException( 637 "malformed input around byte " + count); 638 chararr[chararr_count++]=(char)(((c & 0x1F) << 6) | 639 (char2 & 0x3F)); 640 break; 641 case 14: 642 /* 1110 xxxx 10xx xxxx 10xx xxxx */ 643 count += 3; 644 if (count > utflen) 645 throw new UTFDataFormatException( 646 "malformed input: partial character at end"); 647 char2 = (int) bytearr[count-2]; 648 char3 = (int) bytearr[count-1]; 649 if (((char2 & 0xC0) != 0x80) || ((char3 & 0xC0) != 0x80)) 650 throw new UTFDataFormatException( 651 "malformed input around byte " + (count-1)); 652 chararr[chararr_count++]=(char)(((c & 0x0F) << 12) | 653 ((char2 & 0x3F) << 6) | 654 ((char3 & 0x3F) << 0)); 655 break; 656 default: 657 /* 10xx xxxx, 1111 xxxx */ 658 throw new UTFDataFormatException( 659 "malformed input around byte " + count); 660 } 661 } 662 // The number of chars produced may be less than utflen 663 return new String(chararr, 0, chararr_count); 664 } 665 } 666