1 /* Long.java -- object wrapper for long 2 Copyright (C) 1998, 1999, 2001, 2002, 2004, 2005 Free Software Foundation, Inc. 3 4 This file is part of GNU Classpath. 5 6 GNU Classpath is free software; you can redistribute it and/or modify 7 it under the terms of the GNU General Public License as published by 8 the Free Software Foundation; either version 2, or (at your option) 9 any later version. 10 11 GNU Classpath is distributed in the hope that it will be useful, but 12 WITHOUT ANY WARRANTY; without even the implied warranty of 13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 14 General Public License for more details. 15 16 You should have received a copy of the GNU General Public License 17 along with GNU Classpath; see the file COPYING. If not, write to the 18 Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 19 02110-1301 USA. 20 21 Linking this library statically or dynamically with other modules is 22 making a combined work based on this library. Thus, the terms and 23 conditions of the GNU General Public License cover the whole 24 combination. 25 26 As a special exception, the copyright holders of this library give you 27 permission to link this library with independent modules to produce an 28 executable, regardless of the license terms of these independent 29 modules, and to copy and distribute the resulting executable under 30 terms of your choice, provided that you also meet, for each linked 31 independent module, the terms and conditions of the license of that 32 module. An independent module is a module which is not derived from 33 or based on this library. If you modify this library, you may extend 34 this exception to your version of the library, but you are not 35 obligated to do so. If you do not wish to do so, delete this 36 exception statement from your version. */ 37 38 39 package java.lang; 40 41 /** 42 * Instances of class <code>Long</code> represent primitive 43 * <code>long</code> values. 44 * 45 * Additionally, this class provides various helper functions and variables 46 * related to longs. 47 * 48 * @author Paul Fisher 49 * @author John Keiser 50 * @author Warren Levy 51 * @author Eric Blake (ebb9@email.byu.edu) 52 * @author Tom Tromey (tromey@redhat.com) 53 * @author Andrew John Hughes (gnu_andrew@member.fsf.org) 54 * @author Ian Rogers 55 * @since 1.0 56 * @status updated to 1.5 57 */ 58 public final class Long extends Number implements Comparable<Long> 59 { 60 /** 61 * Compatible with JDK 1.0.2+. 62 */ 63 private static final long serialVersionUID = 4290774380558885855L; 64 65 /** 66 * The minimum value a <code>long</code> can represent is 67 * -9223372036854775808L (or -2<sup>63</sup>). 68 */ 69 public static final long MIN_VALUE = 0x8000000000000000L; 70 71 /** 72 * The maximum value a <code>long</code> can represent is 73 * 9223372036854775807 (or 2<sup>63</sup> - 1). 74 */ 75 public static final long MAX_VALUE = 0x7fffffffffffffffL; 76 77 /** 78 * The primitive type <code>long</code> is represented by this 79 * <code>Class</code> object. 80 * @since 1.1 81 */ 82 public static final Class<Long> TYPE = (Class<Long>) VMClassLoader.getPrimitiveClass ('J'); 83 84 /** 85 * The number of bits needed to represent a <code>long</code>. 86 * @since 1.5 87 */ 88 public static final int SIZE = 64; 89 90 // This caches some Long values, and is used by boxing 91 // conversions via valueOf(). We cache at least -128..127; 92 // these constants control how much we actually cache. 93 private static final int MIN_CACHE = -128; 94 private static final int MAX_CACHE = 127; 95 private static final Long[] longCache = new Long[MAX_CACHE - MIN_CACHE + 1]; 96 static 97 { 98 for (int i=MIN_CACHE; i <= MAX_CACHE; i++) 99 longCache[i - MIN_CACHE] = new Long(i); 100 } 101 102 /** 103 * The immutable value of this Long. 104 * 105 * @serial the wrapped long 106 */ 107 private final long value; 108 109 /** 110 * Create a <code>Long</code> object representing the value of the 111 * <code>long</code> argument. 112 * 113 * @param value the value to use 114 */ Long(long value)115 public Long(long value) 116 { 117 this.value = value; 118 } 119 120 /** 121 * Create a <code>Long</code> object representing the value of the 122 * argument after conversion to a <code>long</code>. 123 * 124 * @param s the string to convert 125 * @throws NumberFormatException if the String does not contain a long 126 * @see #valueOf(String) 127 */ Long(String s)128 public Long(String s) 129 { 130 value = parseLong(s, 10, false); 131 } 132 133 /** 134 * Return the size of a string large enough to hold the given number 135 * 136 * @param num the number we want the string length for (must be positive) 137 * @param radix the radix (base) that will be used for the string 138 * @return a size sufficient for a string of num 139 */ stringSize(long num, int radix)140 private static int stringSize(long num, int radix) { 141 int exp; 142 if (radix < 4) 143 { 144 exp = 1; 145 } 146 else if (radix < 8) 147 { 148 exp = 2; 149 } 150 else if (radix < 16) 151 { 152 exp = 3; 153 } 154 else if (radix < 32) 155 { 156 exp = 4; 157 } 158 else 159 { 160 exp = 5; 161 } 162 int size=0; 163 do 164 { 165 num >>>= exp; 166 size++; 167 } 168 while(num != 0); 169 return size; 170 } 171 172 /** 173 * Converts the <code>long</code> to a <code>String</code> using 174 * the specified radix (base). If the radix exceeds 175 * <code>Character.MIN_RADIX</code> or <code>Character.MAX_RADIX</code>, 10 176 * is used instead. If the result is negative, the leading character is 177 * '-' ('\\u002D'). The remaining characters come from 178 * <code>Character.forDigit(digit, radix)</code> ('0'-'9','a'-'z'). 179 * 180 * @param num the <code>long</code> to convert to <code>String</code> 181 * @param radix the radix (base) to use in the conversion 182 * @return the <code>String</code> representation of the argument 183 */ toString(long num, int radix)184 public static String toString(long num, int radix) 185 { 186 if (radix < Character.MIN_RADIX || radix > Character.MAX_RADIX) 187 radix = 10; 188 189 // Is the value negative? 190 boolean isNeg = num < 0; 191 192 // Is the string a single character? 193 if (!isNeg && num < radix) 194 return new String(digits, (int)num, 1, true); 195 196 // Compute string size and allocate buffer 197 // account for a leading '-' if the value is negative 198 int size; 199 int i; 200 char[] buffer; 201 if (isNeg) 202 { 203 num = -num; 204 205 // When the value is MIN_VALUE, it overflows when made positive 206 if (num < 0) 207 { 208 i = size = stringSize(MAX_VALUE, radix) + 2; 209 buffer = new char[size]; 210 buffer[--i] = digits[(int) (-(num + radix) % radix)]; 211 num = -(num / radix); 212 } 213 else 214 { 215 i = size = stringSize(num, radix) + 1; 216 buffer = new char[size]; 217 } 218 } 219 else 220 { 221 i = size = stringSize(num, radix); 222 buffer = new char[size]; 223 } 224 225 do 226 { 227 buffer[--i] = digits[(int) (num % radix)]; 228 num /= radix; 229 } 230 while (num > 0); 231 232 if (isNeg) 233 buffer[--i] = '-'; 234 235 // Package constructor avoids an array copy. 236 return new String(buffer, i, size - i, true); 237 } 238 239 /** 240 * Converts the <code>long</code> to a <code>String</code> assuming it is 241 * unsigned in base 16. 242 * 243 * @param l the <code>long</code> to convert to <code>String</code> 244 * @return the <code>String</code> representation of the argument 245 */ 246 public static String toHexString(long l) 247 { 248 return toUnsignedString(l, 4); 249 } 250 251 /** 252 * Converts the <code>long</code> to a <code>String</code> assuming it is 253 * unsigned in base 8. 254 * 255 * @param l the <code>long</code> to convert to <code>String</code> 256 * @return the <code>String</code> representation of the argument 257 */ 258 public static String toOctalString(long l) 259 { 260 return toUnsignedString(l, 3); 261 } 262 263 /** 264 * Converts the <code>long</code> to a <code>String</code> assuming it is 265 * unsigned in base 2. 266 * 267 * @param l the <code>long</code> to convert to <code>String</code> 268 * @return the <code>String</code> representation of the argument 269 */ 270 public static String toBinaryString(long l) 271 { 272 return toUnsignedString(l, 1); 273 } 274 275 /** 276 * Converts the <code>long</code> to a <code>String</code> and assumes 277 * a radix of 10. 278 * 279 * @param num the <code>long</code> to convert to <code>String</code> 280 * @return the <code>String</code> representation of the argument 281 * @see #toString(long, int) 282 */ 283 public static String toString(long num) 284 { 285 return toString(num, 10); 286 } 287 288 /** 289 * Converts the specified <code>String</code> into an <code>int</code> 290 * using the specified radix (base). The string must not be <code>null</code> 291 * or empty. It may begin with an optional '-', which will negate the answer, 292 * provided that there are also valid digits. Each digit is parsed as if by 293 * <code>Character.digit(d, radix)</code>, and must be in the range 294 * <code>0</code> to <code>radix - 1</code>. Finally, the result must be 295 * within <code>MIN_VALUE</code> to <code>MAX_VALUE</code>, inclusive. 296 * Unlike Double.parseDouble, you may not have a leading '+'; and 'l' or 297 * 'L' as the last character is only valid in radices 22 or greater, where 298 * it is a digit and not a type indicator. 299 * 300 * @param str the <code>String</code> to convert 301 * @param radix the radix (base) to use in the conversion 302 * @return the <code>String</code> argument converted to <code>long</code> 303 * @throws NumberFormatException if <code>s</code> cannot be parsed as a 304 * <code>long</code> 305 */ 306 public static long parseLong(String str, int radix) 307 { 308 return parseLong(str, radix, false); 309 } 310 311 /** 312 * Converts the specified <code>String</code> into a <code>long</code>. 313 * This function assumes a radix of 10. 314 * 315 * @param s the <code>String</code> to convert 316 * @return the <code>int</code> value of <code>s</code> 317 * @throws NumberFormatException if <code>s</code> cannot be parsed as a 318 * <code>long</code> 319 * @see #parseLong(String, int) 320 */ 321 public static long parseLong(String s) 322 { 323 return parseLong(s, 10, false); 324 } 325 326 /** 327 * Creates a new <code>Long</code> object using the <code>String</code> 328 * and specified radix (base). 329 * 330 * @param s the <code>String</code> to convert 331 * @param radix the radix (base) to convert with 332 * @return the new <code>Long</code> 333 * @throws NumberFormatException if <code>s</code> cannot be parsed as a 334 * <code>long</code> 335 * @see #parseLong(String, int) 336 */ 337 public static Long valueOf(String s, int radix) 338 { 339 return valueOf(parseLong(s, radix, false)); 340 } 341 342 /** 343 * Creates a new <code>Long</code> object using the <code>String</code>, 344 * assuming a radix of 10. 345 * 346 * @param s the <code>String</code> to convert 347 * @return the new <code>Long</code> 348 * @throws NumberFormatException if <code>s</code> cannot be parsed as a 349 * <code>long</code> 350 * @see #Long(String) 351 * @see #parseLong(String) 352 */ 353 public static Long valueOf(String s) 354 { 355 return valueOf(parseLong(s, 10, false)); 356 } 357 358 /** 359 * Returns a <code>Long</code> object wrapping the value. 360 * 361 * @param val the value to wrap 362 * @return the <code>Long</code> 363 * @since 1.5 364 */ 365 public static Long valueOf(long val) 366 { 367 if (val < MIN_CACHE || val > MAX_CACHE) 368 return new Long(val); 369 else 370 return longCache[((int)val) - MIN_CACHE]; 371 } 372 373 /** 374 * Convert the specified <code>String</code> into a <code>Long</code>. 375 * The <code>String</code> may represent decimal, hexadecimal, or 376 * octal numbers. 377 * 378 * <p>The extended BNF grammar is as follows:<br> 379 * <pre> 380 * <em>DecodableString</em>: 381 * ( [ <code>-</code> ] <em>DecimalNumber</em> ) 382 * | ( [ <code>-</code> ] ( <code>0x</code> | <code>0X</code> 383 * | <code>#</code> ) <em>HexDigit</em> { <em>HexDigit</em> } ) 384 * | ( [ <code>-</code> ] <code>0</code> { <em>OctalDigit</em> } ) 385 * <em>DecimalNumber</em>: 386 * <em>DecimalDigit except '0'</em> { <em>DecimalDigit</em> } 387 * <em>DecimalDigit</em>: 388 * <em>Character.digit(d, 10) has value 0 to 9</em> 389 * <em>OctalDigit</em>: 390 * <em>Character.digit(d, 8) has value 0 to 7</em> 391 * <em>DecimalDigit</em>: 392 * <em>Character.digit(d, 16) has value 0 to 15</em> 393 * </pre> 394 * Finally, the value must be in the range <code>MIN_VALUE</code> to 395 * <code>MAX_VALUE</code>, or an exception is thrown. Note that you cannot 396 * use a trailing 'l' or 'L', unlike in Java source code. 397 * 398 * @param str the <code>String</code> to interpret 399 * @return the value of the String as a <code>Long</code> 400 * @throws NumberFormatException if <code>s</code> cannot be parsed as a 401 * <code>long</code> 402 * @throws NullPointerException if <code>s</code> is null 403 * @since 1.2 404 */ 405 public static Long decode(String str) 406 { 407 return valueOf(parseLong(str, 10, true)); 408 } 409 410 /** 411 * Return the value of this <code>Long</code> as a <code>byte</code>. 412 * 413 * @return the byte value 414 */ 415 public byte byteValue() 416 { 417 return (byte) value; 418 } 419 420 /** 421 * Return the value of this <code>Long</code> as a <code>short</code>. 422 * 423 * @return the short value 424 */ 425 public short shortValue() 426 { 427 return (short) value; 428 } 429 430 /** 431 * Return the value of this <code>Long</code> as an <code>int</code>. 432 * 433 * @return the int value 434 */ 435 public int intValue() 436 { 437 return (int) value; 438 } 439 440 /** 441 * Return the value of this <code>Long</code>. 442 * 443 * @return the long value 444 */ 445 public long longValue() 446 { 447 return value; 448 } 449 450 /** 451 * Return the value of this <code>Long</code> as a <code>float</code>. 452 * 453 * @return the float value 454 */ 455 public float floatValue() 456 { 457 return value; 458 } 459 460 /** 461 * Return the value of this <code>Long</code> as a <code>double</code>. 462 * 463 * @return the double value 464 */ 465 public double doubleValue() 466 { 467 return value; 468 } 469 470 /** 471 * Converts the <code>Long</code> value to a <code>String</code> and 472 * assumes a radix of 10. 473 * 474 * @return the <code>String</code> representation 475 */ 476 public String toString() 477 { 478 return toString(value, 10); 479 } 480 481 /** 482 * Return a hashcode representing this Object. <code>Long</code>'s hash 483 * code is calculated by <code>(int) (value ^ (value >> 32))</code>. 484 * 485 * @return this Object's hash code 486 */ 487 public int hashCode() 488 { 489 return (int) (value ^ (value >>> 32)); 490 } 491 492 /** 493 * Returns <code>true</code> if <code>obj</code> is an instance of 494 * <code>Long</code> and represents the same long value. 495 * 496 * @param obj the object to compare 497 * @return whether these Objects are semantically equal 498 */ equals(Object obj)499 public boolean equals(Object obj) 500 { 501 return obj instanceof Long && value == ((Long) obj).value; 502 } 503 504 /** 505 * Get the specified system property as a <code>Long</code>. The 506 * <code>decode()</code> method will be used to interpret the value of 507 * the property. 508 * 509 * @param nm the name of the system property 510 * @return the system property as a <code>Long</code>, or null if the 511 * property is not found or cannot be decoded 512 * @throws SecurityException if accessing the system property is forbidden 513 * @see System#getProperty(String) 514 * @see #decode(String) 515 */ getLong(String nm)516 public static Long getLong(String nm) 517 { 518 return getLong(nm, null); 519 } 520 521 /** 522 * Get the specified system property as a <code>Long</code>, or use a 523 * default <code>long</code> value if the property is not found or is not 524 * decodable. The <code>decode()</code> method will be used to interpret 525 * the value of the property. 526 * 527 * @param nm the name of the system property 528 * @param val the default value 529 * @return the value of the system property, or the default 530 * @throws SecurityException if accessing the system property is forbidden 531 * @see System#getProperty(String) 532 * @see #decode(String) 533 */ getLong(String nm, long val)534 public static Long getLong(String nm, long val) 535 { 536 Long result = getLong(nm, null); 537 return result == null ? valueOf(val) : result; 538 } 539 540 /** 541 * Get the specified system property as a <code>Long</code>, or use a 542 * default <code>Long</code> value if the property is not found or is 543 * not decodable. The <code>decode()</code> method will be used to 544 * interpret the value of the property. 545 * 546 * @param nm the name of the system property 547 * @param def the default value 548 * @return the value of the system property, or the default 549 * @throws SecurityException if accessing the system property is forbidden 550 * @see System#getProperty(String) 551 * @see #decode(String) 552 */ getLong(String nm, Long def)553 public static Long getLong(String nm, Long def) 554 { 555 if (nm == null || "".equals(nm)) 556 return def; 557 nm = System.getProperty(nm); 558 if (nm == null) 559 return def; 560 try 561 { 562 return decode(nm); 563 } 564 catch (NumberFormatException e) 565 { 566 return def; 567 } 568 } 569 570 /** 571 * Compare two Longs numerically by comparing their <code>long</code> 572 * values. The result is positive if the first is greater, negative if the 573 * second is greater, and 0 if the two are equal. 574 * 575 * @param l the Long to compare 576 * @return the comparison 577 * @since 1.2 578 */ compareTo(Long l)579 public int compareTo(Long l) 580 { 581 if (value == l.value) 582 return 0; 583 // Returns just -1 or 1 on inequality; doing math might overflow the long. 584 return value > l.value ? 1 : -1; 585 } 586 587 /** 588 * Compares two unboxed long values. 589 * The result is positive if the first is greater, negative if the second 590 * is greater, and 0 if the two are equal. 591 * 592 * @param x First value to compare. 593 * @param y Second value to compare. 594 * 595 * @return positive int if the first value is greater, negative if the second 596 * is greater, and 0 if the two are equal. 597 * @since 1.7 598 */ compare(long x, long y)599 public static int compare(long x, long y) 600 { 601 return Long.valueOf(x).compareTo(Long.valueOf(y)); 602 } 603 604 /** 605 * Return the number of bits set in x. 606 * @param x value to examine 607 * @since 1.5 608 */ bitCount(long x)609 public static int bitCount(long x) 610 { 611 // Successively collapse alternating bit groups into a sum. 612 x = ((x >> 1) & 0x5555555555555555L) + (x & 0x5555555555555555L); 613 x = ((x >> 2) & 0x3333333333333333L) + (x & 0x3333333333333333L); 614 int v = (int) ((x >>> 32) + x); 615 v = ((v >> 4) & 0x0f0f0f0f) + (v & 0x0f0f0f0f); 616 v = ((v >> 8) & 0x00ff00ff) + (v & 0x00ff00ff); 617 return ((v >> 16) & 0x0000ffff) + (v & 0x0000ffff); 618 } 619 620 /** 621 * Rotate x to the left by distance bits. 622 * @param x the value to rotate 623 * @param distance the number of bits by which to rotate 624 * @since 1.5 625 */ rotateLeft(long x, int distance)626 public static long rotateLeft(long x, int distance) 627 { 628 // This trick works because the shift operators implicitly mask 629 // the shift count. 630 return (x << distance) | (x >>> - distance); 631 } 632 633 /** 634 * Rotate x to the right by distance bits. 635 * @param x the value to rotate 636 * @param distance the number of bits by which to rotate 637 * @since 1.5 638 */ rotateRight(long x, int distance)639 public static long rotateRight(long x, int distance) 640 { 641 // This trick works because the shift operators implicitly mask 642 // the shift count. 643 return (x << - distance) | (x >>> distance); 644 } 645 646 /** 647 * Find the highest set bit in value, and return a new value 648 * with only that bit set. 649 * @param value the value to examine 650 * @since 1.5 651 */ highestOneBit(long value)652 public static long highestOneBit(long value) 653 { 654 value |= value >>> 1; 655 value |= value >>> 2; 656 value |= value >>> 4; 657 value |= value >>> 8; 658 value |= value >>> 16; 659 value |= value >>> 32; 660 return value ^ (value >>> 1); 661 } 662 663 /** 664 * Return the number of leading zeros in value. 665 * @param value the value to examine 666 * @since 1.5 667 */ numberOfLeadingZeros(long value)668 public static int numberOfLeadingZeros(long value) 669 { 670 value |= value >>> 1; 671 value |= value >>> 2; 672 value |= value >>> 4; 673 value |= value >>> 8; 674 value |= value >>> 16; 675 value |= value >>> 32; 676 return bitCount(~value); 677 } 678 679 /** 680 * Find the lowest set bit in value, and return a new value 681 * with only that bit set. 682 * @param value the value to examine 683 * @since 1.5 684 */ lowestOneBit(long value)685 public static long lowestOneBit(long value) 686 { 687 // Classic assembly trick. 688 return value & - value; 689 } 690 691 /** 692 * Find the number of trailing zeros in value. 693 * @param value the value to examine 694 * @since 1.5 695 */ numberOfTrailingZeros(long value)696 public static int numberOfTrailingZeros(long value) 697 { 698 return bitCount((value & -value) - 1); 699 } 700 701 /** 702 * Return 1 if x is positive, -1 if it is negative, and 0 if it is 703 * zero. 704 * @param x the value to examine 705 * @since 1.5 706 */ signum(long x)707 public static int signum(long x) 708 { 709 return (int) ((x >> 63) | (-x >>> 63)); 710 711 // The LHS propagates the sign bit through every bit in the word; 712 // if X < 0, every bit is set to 1, else 0. if X > 0, the RHS 713 // negates x and shifts the resulting 1 in the sign bit to the 714 // LSB, leaving every other bit 0. 715 716 // Hacker's Delight, Section 2-7 717 } 718 719 /** 720 * Reverse the bytes in val. 721 * @since 1.5 722 */ reverseBytes(long val)723 public static long reverseBytes(long val) 724 { 725 int hi = Integer.reverseBytes((int) val); 726 int lo = Integer.reverseBytes((int) (val >>> 32)); 727 return (((long) hi) << 32) | lo; 728 } 729 730 /** 731 * Reverse the bits in val. 732 * @since 1.5 733 */ reverse(long val)734 public static long reverse(long val) 735 { 736 long hi = Integer.reverse((int) val) & 0xffffffffL; 737 long lo = Integer.reverse((int) (val >>> 32)) & 0xffffffffL; 738 return (hi << 32) | lo; 739 } 740 741 /** 742 * Helper for converting unsigned numbers to String. 743 * 744 * @param num the number 745 * @param exp log2(digit) (ie. 1, 3, or 4 for binary, oct, hex) 746 */ toUnsignedString(long num, int exp)747 private static String toUnsignedString(long num, int exp) 748 { 749 // Compute string length 750 int size = 1; 751 long copy = num >>> exp; 752 while (copy != 0) 753 { 754 size++; 755 copy >>>= exp; 756 } 757 // Quick path for single character strings 758 if (size == 1) 759 return new String(digits, (int)num, 1, true); 760 761 // Encode into buffer 762 int mask = (1 << exp) - 1; 763 char[] buffer = new char[size]; 764 int i = size; 765 do 766 { 767 buffer[--i] = digits[(int) num & mask]; 768 num >>>= exp; 769 } 770 while (num != 0); 771 772 // Package constructor avoids an array copy. 773 return new String(buffer, i, size - i, true); 774 } 775 776 /** 777 * Helper for parsing longs. 778 * 779 * @param str the string to parse 780 * @param radix the radix to use, must be 10 if decode is true 781 * @param decode if called from decode 782 * @return the parsed long value 783 * @throws NumberFormatException if there is an error 784 * @throws NullPointerException if decode is true and str is null 785 * @see #parseLong(String, int) 786 * @see #decode(String) 787 */ parseLong(String str, int radix, boolean decode)788 private static long parseLong(String str, int radix, boolean decode) 789 { 790 if (! decode && str == null) 791 throw new NumberFormatException(); 792 int index = 0; 793 int len = str.length(); 794 boolean isNeg = false; 795 if (len == 0) 796 throw new NumberFormatException(); 797 int ch = str.charAt(index); 798 if (ch == '-') 799 { 800 if (len == 1) 801 throw new NumberFormatException(); 802 isNeg = true; 803 ch = str.charAt(++index); 804 } 805 if (decode) 806 { 807 if (ch == '0') 808 { 809 if (++index == len) 810 return 0; 811 if ((str.charAt(index) & ~('x' ^ 'X')) == 'X') 812 { 813 radix = 16; 814 index++; 815 } 816 else 817 radix = 8; 818 } 819 else if (ch == '#') 820 { 821 radix = 16; 822 index++; 823 } 824 } 825 if (index == len) 826 throw new NumberFormatException(); 827 828 long max = MAX_VALUE / radix; 829 // We can't directly write `max = (MAX_VALUE + 1) / radix'. 830 // So instead we fake it. 831 if (isNeg && MAX_VALUE % radix == radix - 1) 832 ++max; 833 834 long val = 0; 835 while (index < len) 836 { 837 if (val < 0 || val > max) 838 throw new NumberFormatException(); 839 840 ch = Character.digit(str.charAt(index++), radix); 841 val = val * radix + ch; 842 if (ch < 0 || (val < 0 && (! isNeg || val != MIN_VALUE))) 843 throw new NumberFormatException(); 844 } 845 return isNeg ? -val : val; 846 } 847 } 848