001/* DataInputStream.java -- FilteredInputStream that implements DataInput 002 Copyright (C) 1998, 1999, 2000, 2001, 2003, 2005, 2008 003 Free Software Foundation 004 005This file is part of GNU Classpath. 006 007GNU Classpath is free software; you can redistribute it and/or modify 008it under the terms of the GNU General Public License as published by 009the Free Software Foundation; either version 2, or (at your option) 010any later version. 011 012GNU Classpath is distributed in the hope that it will be useful, but 013WITHOUT ANY WARRANTY; without even the implied warranty of 014MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 015General Public License for more details. 016 017You should have received a copy of the GNU General Public License 018along with GNU Classpath; see the file COPYING. If not, write to the 019Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02002110-1301 USA. 021 022Linking this library statically or dynamically with other modules is 023making a combined work based on this library. Thus, the terms and 024conditions of the GNU General Public License cover the whole 025combination. 026 027As a special exception, the copyright holders of this library give you 028permission to link this library with independent modules to produce an 029executable, regardless of the license terms of these independent 030modules, and to copy and distribute the resulting executable under 031terms of your choice, provided that you also meet, for each linked 032independent module, the terms and conditions of the license of that 033module. An independent module is a module which is not derived from 034or based on this library. If you modify this library, you may extend 035this exception to your version of the library, but you are not 036obligated to do so. If you do not wish to do so, delete this 037exception statement from your version. */ 038 039package java.io; 040 041import gnu.java.lang.CPStringBuilder; 042 043/* Written using "Java Class Libraries", 2nd edition, ISBN 0-201-31002-3 044 * "The Java Language Specification", ISBN 0-201-63451-1 045 * plus online API docs for JDK 1.2 beta from http://www.javasoft.com. 046 * Status: Believed complete and correct. 047 */ 048 049/** 050 * This subclass of <code>FilteredInputStream</code> implements the 051 * <code>DataInput</code> interface that provides method for reading primitive 052 * Java data types from a stream. 053 * 054 * @see DataInput 055 * 056 * @author Warren Levy (warrenl@cygnus.com) 057 * @author Aaron M. Renn (arenn@urbanophile.com) 058 * @date October 20, 1998. 059 */ 060public class DataInputStream extends FilterInputStream implements DataInput 061{ 062 // Byte buffer, used to make primitive read calls more efficient. 063 byte[] buf = new byte [8]; 064 065 /** 066 * This constructor initializes a new <code>DataInputStream</code> 067 * to read from the specified subordinate stream. 068 * 069 * @param in The subordinate <code>InputStream</code> to read from 070 */ 071 public DataInputStream (InputStream in) 072 { 073 super (in); 074 } 075 076 /** 077 * This method reads bytes from the underlying stream into the specified 078 * byte array buffer. It will attempt to fill the buffer completely, but 079 * may return a short count if there is insufficient data remaining to be 080 * read to fill the buffer. 081 * 082 * @param b The buffer into which bytes will be read. 083 * 084 * @return The actual number of bytes read, or -1 if end of stream reached 085 * before reading any bytes. 086 * 087 * @exception IOException If an error occurs. 088 */ 089 public final int read (byte[] b) throws IOException 090 { 091 return in.read (b, 0, b.length); 092 } 093 094 /** 095 * This method reads bytes from the underlying stream into the specified 096 * byte array buffer. It will attempt to read <code>len</code> bytes and 097 * will start storing them at position <code>off</code> into the buffer. 098 * This method can return a short count if there is insufficient data 099 * remaining to be read to complete the desired read length. 100 * 101 * @param b The buffer into which bytes will be read. 102 * @param off The offset into the buffer to start storing bytes. 103 * @param len The requested number of bytes to read. 104 * 105 * @return The actual number of bytes read, or -1 if end of stream reached 106 * before reading any bytes. 107 * 108 * @exception IOException If an error occurs. 109 */ 110 public final int read (byte[] b, int off, int len) throws IOException 111 { 112 return in.read (b, off, len); 113 } 114 115 /** 116 * This method reads a Java boolean value from an input stream. It does 117 * so by reading a single byte of data. If that byte is zero, then the 118 * value returned is <code>false</code>. If the byte is non-zero, then 119 * the value returned is <code>true</code>. 120 * <p> 121 * This method can read a <code>boolean</code> written by an object 122 * implementing the <code>writeBoolean()</code> method in the 123 * <code>DataOutput</code> interface. 124 * 125 * @return The <code>boolean</code> value read 126 * 127 * @exception EOFException If end of file is reached before reading 128 * the boolean 129 * @exception IOException If any other error occurs 130 * 131 * @see DataOutput#writeBoolean 132 */ 133 public final boolean readBoolean () throws IOException 134 { 135 return convertToBoolean (in.read ()); 136 } 137 138 /** 139 * This method reads a Java byte value from an input stream. The value 140 * is in the range of -128 to 127. 141 * <p> 142 * This method can read a <code>byte</code> written by an object 143 * implementing the <code>writeByte()</code> method in the 144 * <code>DataOutput</code> interface. 145 * 146 * @return The <code>byte</code> value read 147 * 148 * @exception EOFException If end of file is reached before reading the byte 149 * @exception IOException If any other error occurs 150 * 151 * @see DataOutput#writeByte 152 */ 153 public final byte readByte () throws IOException 154 { 155 return convertToByte (in.read ()); 156 } 157 158 /** 159 * This method reads a Java <code>char</code> value from an input stream. 160 * It operates by reading two bytes from the stream and converting them to 161 * a single 16-bit Java <code>char</code>. The two bytes are stored most 162 * significant byte first (i.e., "big endian") regardless of the native 163 * host byte ordering. 164 * <p> 165 * As an example, if <code>byte1</code> and <code>byte2</code> 166 * represent the first and second byte read from the stream 167 * respectively, they will be transformed to a <code>char</code> in 168 * the following manner: 169 * <p> 170 * <code>(char)(((byte1 & 0xFF) << 8) | (byte2 & 0xFF)</code> 171 * <p> 172 * This method can read a <code>char</code> written by an object 173 * implementing the <code>writeChar()</code> method in the 174 * <code>DataOutput</code> interface. 175 * 176 * @return The <code>char</code> value read 177 * 178 * @exception EOFException If end of file is reached before reading the char 179 * @exception IOException If any other error occurs 180 * 181 * @see DataOutput#writeChar 182 */ 183 public final char readChar () throws IOException 184 { 185 readFully (buf, 0, 2); 186 return convertToChar (buf); 187 } 188 189 /** 190 * This method reads a Java double value from an input stream. It operates 191 * by first reading a <code>long</code> value from the stream by calling the 192 * <code>readLong()</code> method in this interface, then converts 193 * that <code>long</code> to a <code>double</code> using the 194 * <code>longBitsToDouble</code> method in the class 195 * <code>java.lang.Double</code> 196 * <p> 197 * This method can read a <code>double</code> written by an object 198 * implementing the <code>writeDouble()</code> method in the 199 * <code>DataOutput</code> interface. 200 * 201 * @return The <code>double</code> value read 202 * 203 * @exception EOFException If end of file is reached before reading 204 * the double 205 * @exception IOException If any other error occurs 206 * 207 * @see DataOutput#writeDouble 208 * @see java.lang.Double#longBitsToDouble 209 */ 210 public final double readDouble () throws IOException 211 { 212 return Double.longBitsToDouble (readLong ()); 213 } 214 215 /** 216 * This method reads a Java float value from an input stream. It 217 * operates by first reading an <code>int</code> value from the 218 * stream by calling the <code>readInt()</code> method in this 219 * interface, then converts that <code>int</code> to a 220 * <code>float</code> using the <code>intBitsToFloat</code> method 221 * in the class <code>java.lang.Float</code> 222 * <p> 223 * This method can read a <code>float</code> written by an object 224 * implementing the <code>writeFloat()</code> method in the 225 * <code>DataOutput</code> interface. 226 * 227 * @return The <code>float</code> value read 228 * 229 * @exception EOFException If end of file is reached before reading the float 230 * @exception IOException If any other error occurs 231 * 232 * @see DataOutput#writeFloat 233 * @see java.lang.Float#intBitsToFloat 234 */ 235 public final float readFloat () throws IOException 236 { 237 return Float.intBitsToFloat (readInt ()); 238 } 239 240 /** 241 * This method reads raw bytes into the passed array until the array is 242 * full. Note that this method blocks until the data is available and 243 * throws an exception if there is not enough data left in the stream to 244 * fill the buffer. Note also that zero length buffers are permitted. 245 * In this case, the method will return immediately without reading any 246 * bytes from the stream. 247 * 248 * @param b The buffer into which to read the data 249 * 250 * @exception EOFException If end of file is reached before filling the 251 * buffer 252 * @exception IOException If any other error occurs 253 */ 254 public final void readFully (byte[] b) throws IOException 255 { 256 readFully (b, 0, b.length); 257 } 258 259 /** 260 * This method reads raw bytes into the passed array <code>buf</code> 261 * starting 262 * <code>offset</code> bytes into the buffer. The number of bytes read 263 * will be 264 * exactly <code>len</code>. Note that this method blocks until the data is 265 * available and throws an exception if there is not enough data left in 266 * the stream to read <code>len</code> bytes. Note also that zero length 267 * buffers are permitted. In this case, the method will return immediately 268 * without reading any bytes from the stream. 269 * 270 * @param buf The buffer into which to read the data 271 * @param offset The offset into the buffer to start storing data 272 * @param len The number of bytes to read into the buffer 273 * 274 * @exception EOFException If end of file is reached before filling the 275 * buffer 276 * @exception IOException If any other error occurs 277 */ 278 public final void readFully (byte[] buf, int offset, int len) throws IOException 279 { 280 if (len < 0) 281 throw new IndexOutOfBoundsException("Negative length: " + len); 282 283 while (len > 0) 284 { 285 // in.read will block until some data is available. 286 int numread = in.read (buf, offset, len); 287 if (numread < 0) 288 throw new EOFException (); 289 len -= numread; 290 offset += numread; 291 } 292 } 293 294 /** 295 * This method reads a Java <code>int</code> value from an input stream 296 * It operates by reading four bytes from the stream and converting them to 297 * a single Java <code>int</code>. The bytes are stored most 298 * significant byte first (i.e., "big endian") regardless of the native 299 * host byte ordering. 300 * <p> 301 * As an example, if <code>byte1</code> through <code>byte4</code> represent 302 * the first four bytes read from the stream, they will be 303 * transformed to an <code>int</code> in the following manner: 304 * <p> 305 * <code>(int)(((byte1 & 0xFF) << 24) + ((byte2 & 0xFF) << 16) + 306 * ((byte3 & 0xFF)<< 8) + (byte4 & 0xFF)))</code> 307 * <p> 308 * The value returned is in the range of -2147483648 to 2147483647. 309 * <p> 310 * This method can read an <code>int</code> written by an object 311 * implementing the <code>writeInt()</code> method in the 312 * <code>DataOutput</code> interface. 313 * 314 * @return The <code>int</code> value read 315 * 316 * @exception EOFException If end of file is reached before reading the int 317 * @exception IOException If any other error occurs 318 * 319 * @see DataOutput#writeInt 320 */ 321 public final int readInt () throws IOException 322 { 323 readFully (buf, 0, 4); 324 return convertToInt (buf); 325 } 326 327 /** 328 * This method reads the next line of text data from an input 329 * stream. It operates by reading bytes and converting those bytes 330 * to <code>char</code> values by treating the byte read as the low 331 * eight bits of the <code>char</code> and using 0 as the high eight 332 * bits. Because of this, it does not support the full 16-bit 333 * Unicode character set. 334 * <p> 335 * The reading of bytes ends when either the end of file or a line 336 * terminator is encountered. The bytes read are then returned as a 337 * <code>String</code> A line terminator is a byte sequence 338 * consisting of either <code>\r</code>, <code>\n</code> or 339 * <code>\r\n</code>. These termination charaters are discarded and 340 * are not returned as part of the string. 341 * <p> 342 * This method can read data that was written by an object implementing the 343 * <code>writeLine()</code> method in <code>DataOutput</code>. 344 * 345 * @return The line read as a <code>String</code> 346 * 347 * @exception IOException If an error occurs 348 * 349 * @see DataOutput 350 * 351 * @deprecated 352 */ 353 public final String readLine() throws IOException 354 { 355 CPStringBuilder strb = new CPStringBuilder(); 356 357 while (true) 358 { 359 int c = in.read(); 360 if (c == -1) // got an EOF 361 return strb.length() > 0 ? strb.toString() : null; 362 if (c == '\r') 363 { 364 int next_c = in.read(); 365 if (next_c != '\n' && next_c != -1) 366 { 367 if (!(in instanceof PushbackInputStream)) 368 in = new PushbackInputStream(in); 369 ((PushbackInputStream) in).unread(next_c); 370 } 371 break; 372 } 373 if (c == '\n') 374 break; 375 strb.append((char) c); 376 } 377 378 return strb.length() > 0 ? strb.toString() : ""; 379 } 380 381 /** 382 * This method reads a Java <code>long</code> value from an input stream 383 * It operates by reading eight bytes from the stream and converting them to 384 * a single Java <code>long</code>. The bytes are stored most 385 * significant byte first (i.e., "big endian") regardless of the native 386 * host byte ordering. 387 * <p> 388 * As an example, if <code>byte1</code> through <code>byte8</code> represent 389 * the first eight bytes read from the stream, they will be 390 * transformed to an <code>long</code> in the following manner: 391 * <p> 392 * <code>(long)(((byte1 & 0xFF) << 56) + ((byte2 & 0xFF) << 48) + 393 * ((byte3 & 0xFF) << 40) + ((byte4 & 0xFF) << 32) + 394 * ((byte5 & 0xFF) << 24) + ((byte6 & 0xFF) << 16) + 395 * ((byte7 & 0xFF) << 8) + (byte8 & 0xFF))) 396 * </code> 397 * <p> 398 * The value returned is in the range of -9223372036854775808 to 399 * 9223372036854775807. 400 * <p> 401 * This method can read an <code>long</code> written by an object 402 * implementing the <code>writeLong()</code> method in the 403 * <code>DataOutput</code> interface. 404 * 405 * @return The <code>long</code> value read 406 * 407 * @exception EOFException If end of file is reached before reading the long 408 * @exception IOException If any other error occurs 409 * 410 * @see DataOutput#writeLong 411 */ 412 public final long readLong () throws IOException 413 { 414 readFully (buf, 0, 8); 415 return convertToLong (buf); 416 } 417 418 /** 419 * This method reads a signed 16-bit value into a Java in from the 420 * stream. It operates by reading two bytes from the stream and 421 * converting them to a single 16-bit Java <code>short</code>. The 422 * two bytes are stored most significant byte first (i.e., "big 423 * endian") regardless of the native host byte ordering. 424 * <p> 425 * As an example, if <code>byte1</code> and <code>byte2</code> 426 * represent the first and second byte read from the stream 427 * respectively, they will be transformed to a <code>short</code>. in 428 * the following manner: 429 * <p> 430 * <code>(short)(((byte1 & 0xFF) << 8) | (byte2 & 0xFF))</code> 431 * <p> 432 * The value returned is in the range of -32768 to 32767. 433 * <p> 434 * This method can read a <code>short</code> written by an object 435 * implementing the <code>writeShort()</code> method in the 436 * <code>DataOutput</code> interface. 437 * 438 * @return The <code>short</code> value read 439 * 440 * @exception EOFException If end of file is reached before reading the value 441 * @exception IOException If any other error occurs 442 * 443 * @see DataOutput#writeShort 444 */ 445 public final short readShort () throws IOException 446 { 447 readFully (buf, 0, 2); 448 return convertToShort (buf); 449 } 450 451 /** 452 * This method reads 8 unsigned bits into a Java <code>int</code> 453 * value from the stream. The value returned is in the range of 0 to 454 * 255. 455 * <p> 456 * This method can read an unsigned byte written by an object 457 * implementing the <code>writeUnsignedByte()</code> method in the 458 * <code>DataOutput</code> interface. 459 * 460 * @return The unsigned bytes value read as a Java <code>int</code>. 461 * 462 * @exception EOFException If end of file is reached before reading the value 463 * @exception IOException If any other error occurs 464 * 465 * @see DataOutput#writeByte 466 */ 467 public final int readUnsignedByte () throws IOException 468 { 469 return convertToUnsignedByte (in.read ()); 470 } 471 472 /** 473 * This method reads 16 unsigned bits into a Java int value from the stream. 474 * It operates by reading two bytes from the stream and converting them to 475 * a single Java <code>int</code> The two bytes are stored most 476 * significant byte first (i.e., "big endian") regardless of the native 477 * host byte ordering. 478 * <p> 479 * As an example, if <code>byte1</code> and <code>byte2</code> 480 * represent the first and second byte read from the stream 481 * respectively, they will be transformed to an <code>int</code> in 482 * the following manner: 483 * <p> 484 * <code>(int)(((byte1 & 0xFF) << 8) + (byte2 & 0xFF))</code> 485 * <p> 486 * The value returned is in the range of 0 to 65535. 487 * <p> 488 * This method can read an unsigned short written by an object 489 * implementing the <code>writeUnsignedShort()</code> method in the 490 * <code>DataOutput</code> interface. 491 * 492 * @return The unsigned short value read as a Java <code>int</code> 493 * 494 * @exception EOFException If end of file is reached before reading the value 495 * @exception IOException If any other error occurs 496 * 497 * @see DataOutput#writeShort 498 */ 499 public final int readUnsignedShort () throws IOException 500 { 501 readFully (buf, 0, 2); 502 return convertToUnsignedShort (buf); 503 } 504 505 /** 506 * This method reads a <code>String</code> from an input stream that 507 * is encoded in a modified UTF-8 format. This format has a leading 508 * two byte sequence that contains the remaining number of bytes to 509 * read. This two byte sequence is read using the 510 * <code>readUnsignedShort()</code> method of this interface. 511 * <p> 512 * After the number of remaining bytes have been determined, these 513 * bytes are read an transformed into <code>char</code> values. 514 * These <code>char</code> values are encoded in the stream using 515 * either a one, two, or three byte format. The particular format 516 * in use can be determined by examining the first byte read. 517 * <p> 518 * If the first byte has a high order bit of 0, then that character 519 * consists on only one byte. This character value consists of 520 * seven bits that are at positions 0 through 6 of the byte. As an 521 * example, if <code>byte1</code> is the byte read from the stream, 522 * it would be converted to a <code>char</code> like so: 523 * <p> 524 * <code>(char)byte1</code> 525 * <p> 526 * If the first byte has 110 as its high order bits, then the 527 * character consists of two bytes. The bits that make up the character 528 * value are in positions 0 through 4 of the first byte and bit positions 529 * 0 through 5 of the second byte. (The second byte should have 530 * 10 as its high order bits). These values are in most significant 531 * byte first (i.e., "big endian") order. 532 * <p> 533 * As an example, if <code>byte1</code> and <code>byte2</code> are 534 * the first two bytes read respectively, and the high order bits of 535 * them match the patterns which indicate a two byte character 536 * encoding, then they would be converted to a Java 537 * <code>char</code> like so: 538 * <p> 539 * <code>(char)(((byte1 & 0x1F) << 6) | (byte2 & 0x3F))</code> 540 * <p> 541 * If the first byte has a 1110 as its high order bits, then the 542 * character consists of three bytes. The bits that make up the character 543 * value are in positions 0 through 3 of the first byte and bit positions 544 * 0 through 5 of the other two bytes. (The second and third bytes should 545 * have 10 as their high order bits). These values are in most 546 * significant byte first (i.e., "big endian") order. 547 * <p> 548 * As an example, if <code>byte1</code> <code>byte2</code> and 549 * <code>byte3</code> are the three bytes read, and the high order 550 * bits of them match the patterns which indicate a three byte 551 * character encoding, then they would be converted to a Java 552 * <code>char</code> like so: 553 * <p> 554 * <code>(char)(((byte1 & 0x0F) << 12) | ((byte2 & 0x3F) << 6) | 555 * (byte3 & 0x3F))</code> 556 * <p> 557 * Note that all characters are encoded in the method that requires 558 * the fewest number of bytes with the exception of the character 559 * with the value of <code>\u0000</code> which is encoded as two 560 * bytes. This is a modification of the UTF standard used to 561 * prevent C language style <code>NUL</code> values from appearing 562 * in the byte stream. 563 * <p> 564 * This method can read data that was written by an object implementing the 565 * <code>writeUTF()</code> method in <code>DataOutput</code> 566 * 567 * @return The <code>String</code> read 568 * 569 * @exception EOFException If end of file is reached before reading 570 * the String 571 * @exception UTFDataFormatException If the data is not in UTF-8 format 572 * @exception IOException If any other error occurs 573 * 574 * @see DataOutput#writeUTF 575 */ 576 public final String readUTF () throws IOException 577 { 578 return readUTF (this); 579 } 580 581 /** 582 * This method reads a String encoded in UTF-8 format from the 583 * specified <code>DataInput</code> source. 584 * 585 * @param in The <code>DataInput</code> source to read from 586 * 587 * @return The String read from the source 588 * 589 * @exception IOException If an error occurs 590 * 591 * @see DataInput#readUTF 592 */ 593 public static final String readUTF(DataInput in) throws IOException 594 { 595 final int UTFlen = in.readUnsignedShort (); 596 597 return readUTF(in, UTFlen); 598 } 599 600 /** 601 * This method is similar to <code>readUTF</code>, but the 602 * UTF-8 byte length is in 64 bits. 603 * This method is not public. It is used by <code>ObjectInputStream</code>. 604 * 605 * @return The <code>String</code> read 606 * 607 * @exception EOFException If end of file is reached before reading 608 * the String 609 * @exception UTFDataFormatException If the data is not in UTF-8 format 610 * @exception IOException If any other error occurs 611 * 612 * @see DataOutput#writeUTFLong 613 */ 614 final String readUTFLong () throws IOException 615 { 616 long l = readLong (); 617 if (l > Integer.MAX_VALUE) 618 throw new IOException("The string length > Integer.MAX_VALUE"); 619 final int UTFlen = (int)l; 620 return readUTF (this, UTFlen); 621 } 622 623 /** 624 * This method performs the main task of <code>readUTF</code> and 625 * <code>readUTFLong</code>. 626 * 627 * @param in The <code>DataInput</code> source to read from 628 * 629 * @param len The UTF-8 byte length of the String to be read 630 * 631 * @return The String read from the source 632 * 633 * @exception IOException If an error occurs 634 * 635 * @see DataInput#readUTF 636 */ 637 private static final String readUTF(DataInput in, int len) throws IOException 638 { 639 byte[] buf = new byte [len]; 640 641 // This blocks until the entire string is available rather than 642 // doing partial processing on the bytes that are available and then 643 // blocking. An advantage of the latter is that Exceptions 644 // could be thrown earlier. The former is a bit cleaner. 645 in.readFully (buf, 0, len); 646 647 return convertFromUTF (buf); 648 } 649 650 /** 651 * This method attempts to skip and discard the specified number of bytes 652 * in the input stream. It may actually skip fewer bytes than requested. 653 * This method will not skip any bytes if passed a negative number of bytes 654 * to skip. 655 * 656 * @param n The requested number of bytes to skip. 657 * 658 * @return The requested number of bytes to skip. 659 * 660 * @exception IOException If an error occurs. 661 * @specnote The JDK docs claim that this returns the number of bytes 662 * actually skipped. The JCL claims that this method can throw an 663 * EOFException. Neither of these appear to be true in the JDK 1.3's 664 * implementation. This tries to implement the actual JDK behaviour. 665 */ 666 public final int skipBytes (int n) throws IOException 667 { 668 if (n <= 0) 669 return 0; 670 try 671 { 672 return (int) in.skip (n); 673 } 674 catch (EOFException x) 675 { 676 // do nothing. 677 } 678 return n; 679 } 680 681 static boolean convertToBoolean (int b) throws EOFException 682 { 683 if (b < 0) 684 throw new EOFException (); 685 686 return (b != 0); 687 } 688 689 static byte convertToByte (int i) throws EOFException 690 { 691 if (i < 0) 692 throw new EOFException (); 693 694 return (byte) i; 695 } 696 697 static int convertToUnsignedByte (int i) throws EOFException 698 { 699 if (i < 0) 700 throw new EOFException (); 701 702 return (i & 0xFF); 703 } 704 705 static char convertToChar (byte[] buf) 706 { 707 return (char) ((buf [0] << 8) 708 | (buf [1] & 0xff)); 709 } 710 711 static short convertToShort (byte[] buf) 712 { 713 return (short) ((buf [0] << 8) 714 | (buf [1] & 0xff)); 715 } 716 717 static int convertToUnsignedShort (byte[] buf) 718 { 719 return (((buf [0] & 0xff) << 8) 720 | (buf [1] & 0xff)); 721 } 722 723 static int convertToInt (byte[] buf) 724 { 725 return (((buf [0] & 0xff) << 24) 726 | ((buf [1] & 0xff) << 16) 727 | ((buf [2] & 0xff) << 8) 728 | (buf [3] & 0xff)); 729 } 730 731 static long convertToLong (byte[] buf) 732 { 733 return (((long)(buf [0] & 0xff) << 56) | 734 ((long)(buf [1] & 0xff) << 48) | 735 ((long)(buf [2] & 0xff) << 40) | 736 ((long)(buf [3] & 0xff) << 32) | 737 ((long)(buf [4] & 0xff) << 24) | 738 ((long)(buf [5] & 0xff) << 16) | 739 ((long)(buf [6] & 0xff) << 8) | 740 ((long)(buf [7] & 0xff))); 741 } 742 743 // FIXME: This method should be re-thought. I suspect we have multiple 744 // UTF-8 decoders floating around. We should use the standard charset 745 // converters, maybe and adding a direct call into one of the new 746 // NIO converters for a super-fast UTF8 decode. 747 static String convertFromUTF (byte[] buf) 748 throws EOFException, UTFDataFormatException 749 { 750 // Give StringBuffer an initial estimated size to avoid 751 // enlarge buffer frequently 752 CPStringBuilder strbuf = new CPStringBuilder (buf.length / 2 + 2); 753 754 for (int i = 0; i < buf.length; ) 755 { 756 if ((buf [i] & 0x80) == 0) // bit pattern 0xxxxxxx 757 strbuf.append ((char) (buf [i++] & 0xFF)); 758 else if ((buf [i] & 0xE0) == 0xC0) // bit pattern 110xxxxx 759 { 760 if (i + 1 >= buf.length 761 || (buf [i + 1] & 0xC0) != 0x80) 762 throw new UTFDataFormatException (); 763 764 strbuf.append((char) (((buf [i++] & 0x1F) << 6) 765 | (buf [i++] & 0x3F))); 766 } 767 else if ((buf [i] & 0xF0) == 0xE0) // bit pattern 1110xxxx 768 { 769 if (i + 2 >= buf.length 770 || (buf [i + 1] & 0xC0) != 0x80 771 || (buf [i + 2] & 0xC0) != 0x80) 772 throw new UTFDataFormatException (); 773 774 strbuf.append ((char) (((buf [i++] & 0x0F) << 12) 775 | ((buf [i++] & 0x3F) << 6) 776 | (buf [i++] & 0x3F))); 777 } 778 else // must be ((buf [i] & 0xF0) == 0xF0 || (buf [i] & 0xC0) == 0x80) 779 throw new UTFDataFormatException (); // bit patterns 1111xxxx or 780 // 10xxxxxx 781 } 782 783 return strbuf.toString (); 784 } 785}