1 /* 2 * Copyright (c) 1994, 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.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 JDK1.0 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</code> 157 * method of <code>DataInput</code>. 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 * @exception EOFException if this input stream reaches the end before 165 * reading all the bytes. 166 * @exception IOException the stream has been closed and the contained 167 * input stream does not support reading after close, or 168 * another I/O error occurs. 169 * @see java.io.FilterInputStream#in 170 */ readFully(byte b[])171 public final void readFully(byte b[]) throws IOException { 172 readFully(b, 0, b.length); 173 } 174 175 /** 176 * See the general contract of the <code>readFully</code> 177 * method of <code>DataInput</code>. 178 * <p> 179 * Bytes 180 * for this operation are read from the contained 181 * input stream. 182 * 183 * @param b the buffer into which the data is read. 184 * @param off the start offset of the data. 185 * @param len the number of bytes to read. 186 * @exception EOFException if this input stream reaches the end before 187 * reading all the bytes. 188 * @exception IOException the stream has been closed and the contained 189 * input stream does not support reading after close, or 190 * another I/O error occurs. 191 * @see java.io.FilterInputStream#in 192 */ readFully(byte b[], int off, int len)193 public final void readFully(byte b[], int off, int len) throws IOException { 194 if (len < 0) 195 throw new IndexOutOfBoundsException(); 196 int n = 0; 197 while (n < len) { 198 int count = in.read(b, off + n, len - n); 199 if (count < 0) 200 throw new EOFException(); 201 n += count; 202 } 203 } 204 205 /** 206 * See the general contract of the <code>skipBytes</code> 207 * method of <code>DataInput</code>. 208 * <p> 209 * Bytes for this operation are read from the contained 210 * input stream. 211 * 212 * @param n the number of bytes to be skipped. 213 * @return the actual number of bytes skipped. 214 * @exception IOException if the contained input stream does not support 215 * seek, or the stream has been closed and 216 * the contained input stream does not support 217 * reading after close, or another I/O error occurs. 218 */ skipBytes(int n)219 public final int skipBytes(int n) throws IOException { 220 int total = 0; 221 int cur = 0; 222 223 while ((total<n) && ((cur = (int) in.skip(n-total)) > 0)) { 224 total += cur; 225 } 226 227 return total; 228 } 229 230 /** 231 * See the general contract of the <code>readBoolean</code> 232 * method of <code>DataInput</code>. 233 * <p> 234 * Bytes for this operation are read from the contained 235 * input stream. 236 * 237 * @return the <code>boolean</code> value read. 238 * @exception EOFException if this input stream has reached the end. 239 * @exception IOException the stream has been closed and the contained 240 * input stream does not support reading after close, or 241 * another I/O error occurs. 242 * @see java.io.FilterInputStream#in 243 */ readBoolean()244 public final boolean readBoolean() throws IOException { 245 int ch = in.read(); 246 if (ch < 0) 247 throw new EOFException(); 248 return (ch != 0); 249 } 250 251 /** 252 * See the general contract of the <code>readByte</code> 253 * method of <code>DataInput</code>. 254 * <p> 255 * Bytes 256 * for this operation are read from the contained 257 * input stream. 258 * 259 * @return the next byte of this input stream as a signed 8-bit 260 * <code>byte</code>. 261 * @exception EOFException if this input stream has reached the end. 262 * @exception IOException the stream has been closed and the contained 263 * input stream does not support reading after close, or 264 * another I/O error occurs. 265 * @see java.io.FilterInputStream#in 266 */ readByte()267 public final byte readByte() throws IOException { 268 int ch = in.read(); 269 if (ch < 0) 270 throw new EOFException(); 271 return (byte)(ch); 272 } 273 274 /** 275 * See the general contract of the <code>readUnsignedByte</code> 276 * method of <code>DataInput</code>. 277 * <p> 278 * Bytes 279 * for this operation are read from the contained 280 * input stream. 281 * 282 * @return the next byte of this input stream, interpreted as an 283 * unsigned 8-bit number. 284 * @exception EOFException if this input stream has reached the end. 285 * @exception IOException the stream has been closed and the contained 286 * input stream does not support reading after close, or 287 * another I/O error occurs. 288 * @see java.io.FilterInputStream#in 289 */ readUnsignedByte()290 public final int readUnsignedByte() throws IOException { 291 int ch = in.read(); 292 if (ch < 0) 293 throw new EOFException(); 294 return ch; 295 } 296 297 /** 298 * See the general contract of the <code>readShort</code> 299 * method of <code>DataInput</code>. 300 * <p> 301 * Bytes 302 * for this operation are read from the contained 303 * input stream. 304 * 305 * @return the next two bytes of this input stream, interpreted as a 306 * signed 16-bit number. 307 * @exception EOFException if this input stream reaches the end before 308 * reading two bytes. 309 * @exception IOException the stream has been closed and the contained 310 * input stream does not support reading after close, or 311 * another I/O error occurs. 312 * @see java.io.FilterInputStream#in 313 */ readShort()314 public final short readShort() throws IOException { 315 // b/30268192 316 // Android-changed: Use read(byte[], int, int) instead of read(). 317 readFully(readBuffer, 0, 2); 318 return Memory.peekShort(readBuffer, 0, ByteOrder.BIG_ENDIAN); 319 } 320 321 /** 322 * See the general contract of the <code>readUnsignedShort</code> 323 * method of <code>DataInput</code>. 324 * <p> 325 * Bytes 326 * for this operation are read from the contained 327 * input stream. 328 * 329 * @return the next two bytes of this input stream, interpreted as an 330 * unsigned 16-bit integer. 331 * @exception EOFException if this input stream reaches the end before 332 * reading two bytes. 333 * @exception IOException the stream has been closed and the contained 334 * input stream does not support reading after close, or 335 * another I/O error occurs. 336 * @see java.io.FilterInputStream#in 337 */ readUnsignedShort()338 public final int readUnsignedShort() throws IOException { 339 // b/30268192 340 // Android-changed: Use read(byte[], int, int) instead of read(). 341 readFully(readBuffer, 0, 2); 342 return Memory.peekShort(readBuffer, 0, ByteOrder.BIG_ENDIAN) & 0xffff; 343 } 344 345 /** 346 * See the general contract of the <code>readChar</code> 347 * method of <code>DataInput</code>. 348 * <p> 349 * Bytes 350 * for this operation are read from the contained 351 * input stream. 352 * 353 * @return the next two bytes of this input stream, interpreted as a 354 * <code>char</code>. 355 * @exception EOFException if this input stream reaches the end before 356 * reading two bytes. 357 * @exception IOException the stream has been closed and the contained 358 * input stream does not support reading after close, or 359 * another I/O error occurs. 360 * @see java.io.FilterInputStream#in 361 */ readChar()362 public final char readChar() throws IOException { 363 // b/30268192 364 // Android-changed: Use read(byte[], int, int) instead of read(). 365 readFully(readBuffer, 0, 2); 366 return (char)Memory.peekShort(readBuffer, 0, ByteOrder.BIG_ENDIAN); 367 } 368 369 /** 370 * See the general contract of the <code>readInt</code> 371 * method of <code>DataInput</code>. 372 * <p> 373 * Bytes 374 * for this operation are read from the contained 375 * input stream. 376 * 377 * @return the next four bytes of this input stream, interpreted as an 378 * <code>int</code>. 379 * @exception EOFException if this input stream reaches the end before 380 * reading four bytes. 381 * @exception IOException the stream has been closed and the contained 382 * input stream does not support reading after close, or 383 * another I/O error occurs. 384 * @see java.io.FilterInputStream#in 385 */ readInt()386 public final int readInt() throws IOException { 387 // b/30268192 388 // Android-changed: Use read(byte[], int, int) instead of read(). 389 readFully(readBuffer, 0, 4); 390 return Memory.peekInt(readBuffer, 0, ByteOrder.BIG_ENDIAN); 391 } 392 393 private byte readBuffer[] = new byte[8]; 394 395 /** 396 * See the general contract of the <code>readLong</code> 397 * method of <code>DataInput</code>. 398 * <p> 399 * Bytes 400 * for this operation are read from the contained 401 * input stream. 402 * 403 * @return the next eight bytes of this input stream, interpreted as a 404 * <code>long</code>. 405 * @exception EOFException if this input stream reaches the end before 406 * reading eight bytes. 407 * @exception IOException the stream has been closed and the contained 408 * input stream does not support reading after close, or 409 * another I/O error occurs. 410 * @see java.io.FilterInputStream#in 411 */ readLong()412 public final long readLong() throws IOException { 413 readFully(readBuffer, 0, 8); 414 return (((long)readBuffer[0] << 56) + 415 ((long)(readBuffer[1] & 255) << 48) + 416 ((long)(readBuffer[2] & 255) << 40) + 417 ((long)(readBuffer[3] & 255) << 32) + 418 ((long)(readBuffer[4] & 255) << 24) + 419 ((readBuffer[5] & 255) << 16) + 420 ((readBuffer[6] & 255) << 8) + 421 ((readBuffer[7] & 255) << 0)); 422 } 423 424 /** 425 * See the general contract of the <code>readFloat</code> 426 * method of <code>DataInput</code>. 427 * <p> 428 * Bytes 429 * for this operation are read from the contained 430 * input stream. 431 * 432 * @return the next four bytes of this input stream, interpreted as a 433 * <code>float</code>. 434 * @exception EOFException if this input stream reaches the end before 435 * reading four bytes. 436 * @exception IOException the stream has been closed and the contained 437 * input stream does not support reading after close, or 438 * another I/O error occurs. 439 * @see java.io.DataInputStream#readInt() 440 * @see java.lang.Float#intBitsToFloat(int) 441 */ readFloat()442 public final float readFloat() throws IOException { 443 return Float.intBitsToFloat(readInt()); 444 } 445 446 /** 447 * See the general contract of the <code>readDouble</code> 448 * method of <code>DataInput</code>. 449 * <p> 450 * Bytes 451 * for this operation are read from the contained 452 * input stream. 453 * 454 * @return the next eight bytes of this input stream, interpreted as a 455 * <code>double</code>. 456 * @exception EOFException if this input stream reaches the end before 457 * reading eight bytes. 458 * @exception IOException the stream has been closed and the contained 459 * input stream does not support reading after close, or 460 * another I/O error occurs. 461 * @see java.io.DataInputStream#readLong() 462 * @see java.lang.Double#longBitsToDouble(long) 463 */ readDouble()464 public final double readDouble() throws IOException { 465 return Double.longBitsToDouble(readLong()); 466 } 467 468 private char lineBuffer[]; 469 470 /** 471 * See the general contract of the <code>readLine</code> 472 * method of <code>DataInput</code>. 473 * <p> 474 * Bytes 475 * for this operation are read from the contained 476 * input stream. 477 * 478 * @deprecated This method does not properly convert bytes to characters. 479 * As of JDK 1.1, the preferred way to read lines of text is via the 480 * <code>BufferedReader.readLine()</code> method. Programs that use the 481 * <code>DataInputStream</code> class to read lines can be converted to use 482 * the <code>BufferedReader</code> class by replacing code of the form: 483 * <blockquote><pre> 484 * DataInputStream d = new DataInputStream(in); 485 * </pre></blockquote> 486 * with: 487 * <blockquote><pre> 488 * BufferedReader d 489 * = new BufferedReader(new InputStreamReader(in)); 490 * </pre></blockquote> 491 * 492 * @return the next line of text from this input stream. 493 * @exception IOException if an I/O error occurs. 494 * @see java.io.BufferedReader#readLine() 495 * @see java.io.FilterInputStream#in 496 */ 497 @Deprecated readLine()498 public final String readLine() throws IOException { 499 char buf[] = lineBuffer; 500 501 if (buf == null) { 502 buf = lineBuffer = new char[128]; 503 } 504 505 int room = buf.length; 506 int offset = 0; 507 int c; 508 509 loop: while (true) { 510 switch (c = in.read()) { 511 case -1: 512 case '\n': 513 break loop; 514 515 case '\r': 516 int c2 = in.read(); 517 if ((c2 != '\n') && (c2 != -1)) { 518 if (!(in instanceof PushbackInputStream)) { 519 this.in = new PushbackInputStream(in); 520 } 521 ((PushbackInputStream)in).unread(c2); 522 } 523 break loop; 524 525 default: 526 if (--room < 0) { 527 buf = new char[offset + 128]; 528 room = buf.length - offset - 1; 529 System.arraycopy(lineBuffer, 0, buf, 0, offset); 530 lineBuffer = buf; 531 } 532 buf[offset++] = (char) c; 533 break; 534 } 535 } 536 if ((c == -1) && (offset == 0)) { 537 return null; 538 } 539 return String.copyValueOf(buf, 0, offset); 540 } 541 542 /** 543 * See the general contract of the <code>readUTF</code> 544 * method of <code>DataInput</code>. 545 * <p> 546 * Bytes 547 * for this operation are read from the contained 548 * input stream. 549 * 550 * @return a Unicode string. 551 * @exception EOFException if this input stream reaches the end before 552 * reading all the bytes. 553 * @exception IOException the stream has been closed and the contained 554 * input stream does not support reading after close, or 555 * another I/O error occurs. 556 * @exception UTFDataFormatException if the bytes do not represent a valid 557 * modified UTF-8 encoding of a string. 558 * @see java.io.DataInputStream#readUTF(java.io.DataInput) 559 */ readUTF()560 public final String readUTF() throws IOException { 561 return readUTF(this); 562 } 563 564 /** 565 * Reads from the 566 * stream <code>in</code> a representation 567 * of a Unicode character string encoded in 568 * <a href="DataInput.html#modified-utf-8">modified UTF-8</a> format; 569 * this string of characters is then returned as a <code>String</code>. 570 * The details of the modified UTF-8 representation 571 * are exactly the same as for the <code>readUTF</code> 572 * method of <code>DataInput</code>. 573 * 574 * @param in a data input stream. 575 * @return a Unicode string. 576 * @exception EOFException if the input stream reaches the end 577 * before all the bytes. 578 * @exception IOException the stream has been closed and the contained 579 * input stream does not support reading after close, or 580 * another I/O error occurs. 581 * @exception UTFDataFormatException if the bytes do not represent a 582 * valid modified UTF-8 encoding of a Unicode string. 583 * @see java.io.DataInputStream#readUnsignedShort() 584 */ readUTF(DataInput in)585 public final static String readUTF(DataInput in) throws IOException { 586 int utflen = in.readUnsignedShort(); 587 byte[] bytearr = null; 588 char[] chararr = null; 589 if (in instanceof DataInputStream) { 590 DataInputStream dis = (DataInputStream)in; 591 if (dis.bytearr.length < utflen){ 592 dis.bytearr = new byte[utflen*2]; 593 dis.chararr = new char[utflen*2]; 594 } 595 chararr = dis.chararr; 596 bytearr = dis.bytearr; 597 } else { 598 bytearr = new byte[utflen]; 599 chararr = new char[utflen]; 600 } 601 602 int c, char2, char3; 603 int count = 0; 604 int chararr_count=0; 605 606 in.readFully(bytearr, 0, utflen); 607 608 while (count < utflen) { 609 c = (int) bytearr[count] & 0xff; 610 if (c > 127) break; 611 count++; 612 chararr[chararr_count++]=(char)c; 613 } 614 615 while (count < utflen) { 616 c = (int) bytearr[count] & 0xff; 617 switch (c >> 4) { 618 case 0: case 1: case 2: case 3: case 4: case 5: case 6: case 7: 619 /* 0xxxxxxx*/ 620 count++; 621 chararr[chararr_count++]=(char)c; 622 break; 623 case 12: case 13: 624 /* 110x xxxx 10xx xxxx*/ 625 count += 2; 626 if (count > utflen) 627 throw new UTFDataFormatException( 628 "malformed input: partial character at end"); 629 char2 = (int) bytearr[count-1]; 630 if ((char2 & 0xC0) != 0x80) 631 throw new UTFDataFormatException( 632 "malformed input around byte " + count); 633 chararr[chararr_count++]=(char)(((c & 0x1F) << 6) | 634 (char2 & 0x3F)); 635 break; 636 case 14: 637 /* 1110 xxxx 10xx xxxx 10xx xxxx */ 638 count += 3; 639 if (count > utflen) 640 throw new UTFDataFormatException( 641 "malformed input: partial character at end"); 642 char2 = (int) bytearr[count-2]; 643 char3 = (int) bytearr[count-1]; 644 if (((char2 & 0xC0) != 0x80) || ((char3 & 0xC0) != 0x80)) 645 throw new UTFDataFormatException( 646 "malformed input around byte " + (count-1)); 647 chararr[chararr_count++]=(char)(((c & 0x0F) << 12) | 648 ((char2 & 0x3F) << 6) | 649 ((char3 & 0x3F) << 0)); 650 break; 651 default: 652 /* 10xx xxxx, 1111 xxxx */ 653 throw new UTFDataFormatException( 654 "malformed input around byte " + count); 655 } 656 } 657 // The number of chars produced may be less than utflen 658 return new String(chararr, 0, chararr_count); 659 } 660 } 661