1 /* 2 * Copyright (c) 1994, 2013, 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.lang; 27 28 import java.lang.annotation.Native; 29 import java.math.*; 30 import java.util.Objects; 31 import jdk.internal.HotSpotIntrinsicCandidate; 32 33 import static java.lang.String.COMPACT_STRINGS; 34 import static java.lang.String.LATIN1; 35 import static java.lang.String.UTF16; 36 37 /** 38 * The {@code Long} class wraps a value of the primitive type {@code 39 * long} in an object. An object of type {@code Long} contains a 40 * single field whose type is {@code long}. 41 * 42 * <p> In addition, this class provides several methods for converting 43 * a {@code long} to a {@code String} and a {@code String} to a {@code 44 * long}, as well as other constants and methods useful when dealing 45 * with a {@code long}. 46 * 47 * <p>Implementation note: The implementations of the "bit twiddling" 48 * methods (such as {@link #highestOneBit(long) highestOneBit} and 49 * {@link #numberOfTrailingZeros(long) numberOfTrailingZeros}) are 50 * based on material from Henry S. Warren, Jr.'s <i>Hacker's 51 * Delight</i>, (Addison Wesley, 2002). 52 * 53 * @author Lee Boynton 54 * @author Arthur van Hoff 55 * @author Josh Bloch 56 * @author Joseph D. Darcy 57 * @since 1.0 58 */ 59 public final class Long extends Number implements Comparable<Long> { 60 /** 61 * A constant holding the minimum value a {@code long} can 62 * have, -2<sup>63</sup>. 63 */ 64 @Native public static final long MIN_VALUE = 0x8000000000000000L; 65 66 /** 67 * A constant holding the maximum value a {@code long} can 68 * have, 2<sup>63</sup>-1. 69 */ 70 @Native public static final long MAX_VALUE = 0x7fffffffffffffffL; 71 72 /** 73 * The {@code Class} instance representing the primitive type 74 * {@code long}. 75 * 76 * @since 1.1 77 */ 78 @SuppressWarnings("unchecked") 79 public static final Class<Long> TYPE = (Class<Long>) Class.getPrimitiveClass("long"); 80 81 /** 82 * Returns a string representation of the first argument in the 83 * radix specified by the second argument. 84 * 85 * <p>If the radix is smaller than {@code Character.MIN_RADIX} 86 * or larger than {@code Character.MAX_RADIX}, then the radix 87 * {@code 10} is used instead. 88 * 89 * <p>If the first argument is negative, the first element of the 90 * result is the ASCII minus sign {@code '-'} 91 * ({@code '\u005Cu002d'}). If the first argument is not 92 * negative, no sign character appears in the result. 93 * 94 * <p>The remaining characters of the result represent the magnitude 95 * of the first argument. If the magnitude is zero, it is 96 * represented by a single zero character {@code '0'} 97 * ({@code '\u005Cu0030'}); otherwise, the first character of 98 * the representation of the magnitude will not be the zero 99 * character. The following ASCII characters are used as digits: 100 * 101 * <blockquote> 102 * {@code 0123456789abcdefghijklmnopqrstuvwxyz} 103 * </blockquote> 104 * 105 * These are {@code '\u005Cu0030'} through 106 * {@code '\u005Cu0039'} and {@code '\u005Cu0061'} through 107 * {@code '\u005Cu007a'}. If {@code radix} is 108 * <var>N</var>, then the first <var>N</var> of these characters 109 * are used as radix-<var>N</var> digits in the order shown. Thus, 110 * the digits for hexadecimal (radix 16) are 111 * {@code 0123456789abcdef}. If uppercase letters are 112 * desired, the {@link java.lang.String#toUpperCase()} method may 113 * be called on the result: 114 * 115 * <blockquote> 116 * {@code Long.toString(n, 16).toUpperCase()} 117 * </blockquote> 118 * 119 * @param i a {@code long} to be converted to a string. 120 * @param radix the radix to use in the string representation. 121 * @return a string representation of the argument in the specified radix. 122 * @see java.lang.Character#MAX_RADIX 123 * @see java.lang.Character#MIN_RADIX 124 */ 125 public static String toString(long i, int radix) { 126 if (radix < Character.MIN_RADIX || radix > Character.MAX_RADIX) 127 radix = 10; 128 if (radix == 10) 129 return toString(i); 130 131 if (COMPACT_STRINGS) { 132 byte[] buf = new byte[65]; 133 int charPos = 64; 134 boolean negative = (i < 0); 135 136 if (!negative) { 137 i = -i; 138 } 139 140 while (i <= -radix) { 141 buf[charPos--] = (byte)Integer.digits[(int)(-(i % radix))]; 142 i = i / radix; 143 } 144 buf[charPos] = (byte)Integer.digits[(int)(-i)]; 145 146 if (negative) { 147 buf[--charPos] = '-'; 148 } 149 return StringLatin1.newString(buf, charPos, (65 - charPos)); 150 } 151 return toStringUTF16(i, radix); 152 } 153 154 private static String toStringUTF16(long i, int radix) { 155 byte[] buf = new byte[65 * 2]; 156 int charPos = 64; 157 boolean negative = (i < 0); 158 if (!negative) { 159 i = -i; 160 } 161 while (i <= -radix) { 162 StringUTF16.putChar(buf, charPos--, Integer.digits[(int)(-(i % radix))]); 163 i = i / radix; 164 } 165 StringUTF16.putChar(buf, charPos, Integer.digits[(int)(-i)]); 166 if (negative) { 167 StringUTF16.putChar(buf, --charPos, '-'); 168 } 169 return StringUTF16.newString(buf, charPos, (65 - charPos)); 170 } 171 172 /** 173 * Returns a string representation of the first argument as an 174 * unsigned integer value in the radix specified by the second 175 * argument. 176 * 177 * <p>If the radix is smaller than {@code Character.MIN_RADIX} 178 * or larger than {@code Character.MAX_RADIX}, then the radix 179 * {@code 10} is used instead. 180 * 181 * <p>Note that since the first argument is treated as an unsigned 182 * value, no leading sign character is printed. 183 * 184 * <p>If the magnitude is zero, it is represented by a single zero 185 * character {@code '0'} ({@code '\u005Cu0030'}); otherwise, 186 * the first character of the representation of the magnitude will 187 * not be the zero character. 188 * 189 * <p>The behavior of radixes and the characters used as digits 190 * are the same as {@link #toString(long, int) toString}. 191 * 192 * @param i an integer to be converted to an unsigned string. 193 * @param radix the radix to use in the string representation. 194 * @return an unsigned string representation of the argument in the specified radix. 195 * @see #toString(long, int) 196 * @since 1.8 197 */ 198 public static String toUnsignedString(long i, int radix) { 199 if (i >= 0) 200 return toString(i, radix); 201 else { 202 switch (radix) { 203 case 2: 204 return toBinaryString(i); 205 206 case 4: 207 return toUnsignedString0(i, 2); 208 209 case 8: 210 return toOctalString(i); 211 212 case 10: 213 /* 214 * We can get the effect of an unsigned division by 10 215 * on a long value by first shifting right, yielding a 216 * positive value, and then dividing by 5. This 217 * allows the last digit and preceding digits to be 218 * isolated more quickly than by an initial conversion 219 * to BigInteger. 220 */ 221 long quot = (i >>> 1) / 5; 222 long rem = i - quot * 10; 223 return toString(quot) + rem; 224 225 case 16: 226 return toHexString(i); 227 228 case 32: 229 return toUnsignedString0(i, 5); 230 231 default: 232 return toUnsignedBigInteger(i).toString(radix); 233 } 234 } 235 } 236 237 /** 238 * Return a BigInteger equal to the unsigned value of the 239 * argument. 240 */ 241 private static BigInteger toUnsignedBigInteger(long i) { 242 if (i >= 0L) 243 return BigInteger.valueOf(i); 244 else { 245 int upper = (int) (i >>> 32); 246 int lower = (int) i; 247 248 // return (upper << 32) + lower 249 return (BigInteger.valueOf(Integer.toUnsignedLong(upper))).shiftLeft(32). 250 add(BigInteger.valueOf(Integer.toUnsignedLong(lower))); 251 } 252 } 253 254 /** 255 * Returns a string representation of the {@code long} 256 * argument as an unsigned integer in base 16. 257 * 258 * <p>The unsigned {@code long} value is the argument plus 259 * 2<sup>64</sup> if the argument is negative; otherwise, it is 260 * equal to the argument. This value is converted to a string of 261 * ASCII digits in hexadecimal (base 16) with no extra 262 * leading {@code 0}s. 263 * 264 * <p>The value of the argument can be recovered from the returned 265 * string {@code s} by calling {@link 266 * Long#parseUnsignedLong(String, int) Long.parseUnsignedLong(s, 267 * 16)}. 268 * 269 * <p>If the unsigned magnitude is zero, it is represented by a 270 * single zero character {@code '0'} ({@code '\u005Cu0030'}); 271 * otherwise, the first character of the representation of the 272 * unsigned magnitude will not be the zero character. The 273 * following characters are used as hexadecimal digits: 274 * 275 * <blockquote> 276 * {@code 0123456789abcdef} 277 * </blockquote> 278 * 279 * These are the characters {@code '\u005Cu0030'} through 280 * {@code '\u005Cu0039'} and {@code '\u005Cu0061'} through 281 * {@code '\u005Cu0066'}. If uppercase letters are desired, 282 * the {@link java.lang.String#toUpperCase()} method may be called 283 * on the result: 284 * 285 * <blockquote> 286 * {@code Long.toHexString(n).toUpperCase()} 287 * </blockquote> 288 * 289 * @param i a {@code long} to be converted to a string. 290 * @return the string representation of the unsigned {@code long} 291 * value represented by the argument in hexadecimal 292 * (base 16). 293 * @see #parseUnsignedLong(String, int) 294 * @see #toUnsignedString(long, int) 295 * @since 1.0.2 296 */ 297 public static String toHexString(long i) { 298 return toUnsignedString0(i, 4); 299 } 300 301 /** 302 * Returns a string representation of the {@code long} 303 * argument as an unsigned integer in base 8. 304 * 305 * <p>The unsigned {@code long} value is the argument plus 306 * 2<sup>64</sup> if the argument is negative; otherwise, it is 307 * equal to the argument. This value is converted to a string of 308 * ASCII digits in octal (base 8) with no extra leading 309 * {@code 0}s. 310 * 311 * <p>The value of the argument can be recovered from the returned 312 * string {@code s} by calling {@link 313 * Long#parseUnsignedLong(String, int) Long.parseUnsignedLong(s, 314 * 8)}. 315 * 316 * <p>If the unsigned magnitude is zero, it is represented by a 317 * single zero character {@code '0'} ({@code '\u005Cu0030'}); 318 * otherwise, the first character of the representation of the 319 * unsigned magnitude will not be the zero character. The 320 * following characters are used as octal digits: 321 * 322 * <blockquote> 323 * {@code 01234567} 324 * </blockquote> 325 * 326 * These are the characters {@code '\u005Cu0030'} through 327 * {@code '\u005Cu0037'}. 328 * 329 * @param i a {@code long} to be converted to a string. 330 * @return the string representation of the unsigned {@code long} 331 * value represented by the argument in octal (base 8). 332 * @see #parseUnsignedLong(String, int) 333 * @see #toUnsignedString(long, int) 334 * @since 1.0.2 335 */ 336 public static String toOctalString(long i) { 337 return toUnsignedString0(i, 3); 338 } 339 340 /** 341 * Returns a string representation of the {@code long} 342 * argument as an unsigned integer in base 2. 343 * 344 * <p>The unsigned {@code long} value is the argument plus 345 * 2<sup>64</sup> if the argument is negative; otherwise, it is 346 * equal to the argument. This value is converted to a string of 347 * ASCII digits in binary (base 2) with no extra leading 348 * {@code 0}s. 349 * 350 * <p>The value of the argument can be recovered from the returned 351 * string {@code s} by calling {@link 352 * Long#parseUnsignedLong(String, int) Long.parseUnsignedLong(s, 353 * 2)}. 354 * 355 * <p>If the unsigned magnitude is zero, it is represented by a 356 * single zero character {@code '0'} ({@code '\u005Cu0030'}); 357 * otherwise, the first character of the representation of the 358 * unsigned magnitude will not be the zero character. The 359 * characters {@code '0'} ({@code '\u005Cu0030'}) and {@code 360 * '1'} ({@code '\u005Cu0031'}) are used as binary digits. 361 * 362 * @param i a {@code long} to be converted to a string. 363 * @return the string representation of the unsigned {@code long} 364 * value represented by the argument in binary (base 2). 365 * @see #parseUnsignedLong(String, int) 366 * @see #toUnsignedString(long, int) 367 * @since 1.0.2 368 */ 369 public static String toBinaryString(long i) { 370 return toUnsignedString0(i, 1); 371 } 372 373 /** 374 * Format a long (treated as unsigned) into a String. 375 * @param val the value to format 376 * @param shift the log2 of the base to format in (4 for hex, 3 for octal, 1 for binary) 377 */ 378 static String toUnsignedString0(long val, int shift) { 379 // assert shift > 0 && shift <=5 : "Illegal shift value"; 380 int mag = Long.SIZE - Long.numberOfLeadingZeros(val); 381 int chars = Math.max(((mag + (shift - 1)) / shift), 1); 382 383 if (COMPACT_STRINGS) { 384 byte[] buf = new byte[chars]; 385 formatUnsignedLong0(val, shift, buf, 0, chars); 386 return new String(buf, LATIN1); 387 } else { 388 byte[] buf = new byte[chars * 2]; 389 formatUnsignedLong0UTF16(val, shift, buf, 0, chars); 390 return new String(buf, UTF16); 391 } 392 } 393 394 /** 395 * Format a long (treated as unsigned) into a character buffer. If 396 * {@code len} exceeds the formatted ASCII representation of {@code val}, 397 * {@code buf} will be padded with leading zeroes. 398 * 399 * @param val the unsigned long to format 400 * @param shift the log2 of the base to format in (4 for hex, 3 for octal, 1 for binary) 401 * @param buf the character buffer to write to 402 * @param offset the offset in the destination buffer to start at 403 * @param len the number of characters to write 404 */ 405 static void formatUnsignedLong(long val, int shift, char[] buf, int offset, int len) { 406 // assert shift > 0 && shift <=5 : "Illegal shift value"; 407 // assert offset >= 0 && offset < buf.length : "illegal offset"; 408 // assert len > 0 && (offset + len) <= buf.length : "illegal length"; 409 int charPos = offset + len; 410 int radix = 1 << shift; 411 int mask = radix - 1; 412 do { 413 buf[--charPos] = Integer.digits[((int) val) & mask]; 414 val >>>= shift; 415 } while (charPos > offset); 416 } 417 418 /** byte[]/LATIN1 version */ 419 static void formatUnsignedLong0(long val, int shift, byte[] buf, int offset, int len) { 420 int charPos = offset + len; 421 int radix = 1 << shift; 422 int mask = radix - 1; 423 do { 424 buf[--charPos] = (byte)Integer.digits[((int) val) & mask]; 425 val >>>= shift; 426 } while (charPos > offset); 427 } 428 429 /** byte[]/UTF16 version */ 430 static void formatUnsignedLong0UTF16(long val, int shift, byte[] buf, int offset, int len) { 431 int charPos = offset + len; 432 int radix = 1 << shift; 433 int mask = radix - 1; 434 do { 435 StringUTF16.putChar(buf, --charPos, Integer.digits[((int) val) & mask]); 436 val >>>= shift; 437 } while (charPos > offset); 438 } 439 440 /** 441 * Returns a {@code String} object representing the specified 442 * {@code long}. The argument is converted to signed decimal 443 * representation and returned as a string, exactly as if the 444 * argument and the radix 10 were given as arguments to the {@link 445 * #toString(long, int)} method. 446 * 447 * @param i a {@code long} to be converted. 448 * @return a string representation of the argument in base 10. 449 */ 450 public static String toString(long i) { 451 int size = stringSize(i); 452 if (COMPACT_STRINGS) { 453 byte[] buf = new byte[size]; 454 getChars(i, size, buf); 455 return new String(buf, LATIN1); 456 } else { 457 byte[] buf = new byte[size * 2]; 458 getCharsUTF16(i, size, buf); 459 return new String(buf, UTF16); 460 } 461 } 462 463 /** 464 * Returns a string representation of the argument as an unsigned 465 * decimal value. 466 * 467 * The argument is converted to unsigned decimal representation 468 * and returned as a string exactly as if the argument and radix 469 * 10 were given as arguments to the {@link #toUnsignedString(long, 470 * int)} method. 471 * 472 * @param i an integer to be converted to an unsigned string. 473 * @return an unsigned string representation of the argument. 474 * @see #toUnsignedString(long, int) 475 * @since 1.8 476 */ 477 public static String toUnsignedString(long i) { 478 return toUnsignedString(i, 10); 479 } 480 481 /** 482 * Places characters representing the long i into the 483 * character array buf. The characters are placed into 484 * the buffer backwards starting with the least significant 485 * digit at the specified index (exclusive), and working 486 * backwards from there. 487 * 488 * @implNote This method converts positive inputs into negative 489 * values, to cover the Long.MIN_VALUE case. Converting otherwise 490 * (negative to positive) will expose -Long.MIN_VALUE that overflows 491 * long. 492 */ 493 static void getChars(long i, int index, byte[] buf) { 494 long q; 495 int r; 496 int charPos = index; 497 498 boolean negative = (i < 0); 499 if (!negative) { 500 i = -i; 501 } 502 503 // Get 2 digits/iteration using longs until quotient fits into an int 504 while (i <= Integer.MIN_VALUE) { 505 q = i / 100; 506 r = (int)((q * 100) - i); 507 i = q; 508 buf[--charPos] = Integer.DigitOnes[r]; 509 buf[--charPos] = Integer.DigitTens[r]; 510 } 511 512 // Get 2 digits/iteration using ints 513 int q2; 514 int i2 = (int)i; 515 while (i2 <= -100) { 516 q2 = i2 / 100; 517 r = (q2 * 100) - i2; 518 i2 = q2; 519 buf[--charPos] = Integer.DigitOnes[r]; 520 buf[--charPos] = Integer.DigitTens[r]; 521 } 522 523 // We know there are at most two digits left at this point. 524 q2 = i2 / 10; 525 r = (q2 * 10) - i2; 526 buf[--charPos] = (byte)('0' + r); 527 528 // Whatever left is the remaining digit. 529 if (q2 < 0) { 530 buf[--charPos] = (byte)('0' - q2); 531 } 532 533 if (negative) { 534 buf[--charPos] = (byte)'-'; 535 } 536 } 537 538 static void getCharsUTF16(long i, int index, byte[] buf) { 539 long q; 540 int r; 541 int charPos = index; 542 543 boolean negative = (i < 0); 544 if (!negative) { 545 i = -i; 546 } 547 548 // Get 2 digits/iteration using longs until quotient fits into an int 549 while (i <= Integer.MIN_VALUE) { 550 q = i / 100; 551 r = (int)((q * 100) - i); 552 i = q; 553 StringUTF16.putChar(buf, --charPos, Integer.DigitOnes[r]); 554 StringUTF16.putChar(buf, --charPos, Integer.DigitTens[r]); 555 } 556 557 // Get 2 digits/iteration using ints 558 int q2; 559 int i2 = (int)i; 560 while (i2 <= -100) { 561 q2 = i2 / 100; 562 r = (q2 * 100) - i2; 563 i2 = q2; 564 StringUTF16.putChar(buf, --charPos, Integer.DigitOnes[r]); 565 StringUTF16.putChar(buf, --charPos, Integer.DigitTens[r]); 566 } 567 568 // We know there are at most two digits left at this point. 569 q2 = i2 / 10; 570 r = (q2 * 10) - i2; 571 StringUTF16.putChar(buf, --charPos, '0' + r); 572 573 // Whatever left is the remaining digit. 574 if (q2 < 0) { 575 StringUTF16.putChar(buf, --charPos, '0' - q2); 576 } 577 578 if (negative) { 579 StringUTF16.putChar(buf, --charPos, '-'); 580 } 581 } 582 583 /** 584 * Returns the string representation size for a given long value. 585 * 586 * @param x long value 587 * @return string size 588 * 589 * @implNote There are other ways to compute this: e.g. binary search, 590 * but values are biased heavily towards zero, and therefore linear search 591 * wins. The iteration results are also routinely inlined in the generated 592 * code after loop unrolling. 593 */ 594 static int stringSize(long x) { 595 int d = 1; 596 if (x >= 0) { 597 d = 0; 598 x = -x; 599 } 600 long p = -10; 601 for (int i = 1; i < 19; i++) { 602 if (x > p) 603 return i + d; 604 p = 10 * p; 605 } 606 return 19 + d; 607 } 608 609 /** 610 * Parses the string argument as a signed {@code long} in the 611 * radix specified by the second argument. The characters in the 612 * string must all be digits of the specified radix (as determined 613 * by whether {@link java.lang.Character#digit(char, int)} returns 614 * a nonnegative value), except that the first character may be an 615 * ASCII minus sign {@code '-'} ({@code '\u005Cu002D'}) to 616 * indicate a negative value or an ASCII plus sign {@code '+'} 617 * ({@code '\u005Cu002B'}) to indicate a positive value. The 618 * resulting {@code long} value is returned. 619 * 620 * <p>Note that neither the character {@code L} 621 * ({@code '\u005Cu004C'}) nor {@code l} 622 * ({@code '\u005Cu006C'}) is permitted to appear at the end 623 * of the string as a type indicator, as would be permitted in 624 * Java programming language source code - except that either 625 * {@code L} or {@code l} may appear as a digit for a 626 * radix greater than or equal to 22. 627 * 628 * <p>An exception of type {@code NumberFormatException} is 629 * thrown if any of the following situations occurs: 630 * <ul> 631 * 632 * <li>The first argument is {@code null} or is a string of 633 * length zero. 634 * 635 * <li>The {@code radix} is either smaller than {@link 636 * java.lang.Character#MIN_RADIX} or larger than {@link 637 * java.lang.Character#MAX_RADIX}. 638 * 639 * <li>Any character of the string is not a digit of the specified 640 * radix, except that the first character may be a minus sign 641 * {@code '-'} ({@code '\u005Cu002d'}) or plus sign {@code 642 * '+'} ({@code '\u005Cu002B'}) provided that the string is 643 * longer than length 1. 644 * 645 * <li>The value represented by the string is not a value of type 646 * {@code long}. 647 * </ul> 648 * 649 * <p>Examples: 650 * <blockquote><pre> 651 * parseLong("0", 10) returns 0L 652 * parseLong("473", 10) returns 473L 653 * parseLong("+42", 10) returns 42L 654 * parseLong("-0", 10) returns 0L 655 * parseLong("-FF", 16) returns -255L 656 * parseLong("1100110", 2) returns 102L 657 * parseLong("99", 8) throws a NumberFormatException 658 * parseLong("Hazelnut", 10) throws a NumberFormatException 659 * parseLong("Hazelnut", 36) returns 1356099454469L 660 * </pre></blockquote> 661 * 662 * @param s the {@code String} containing the 663 * {@code long} representation to be parsed. 664 * @param radix the radix to be used while parsing {@code s}. 665 * @return the {@code long} represented by the string argument in 666 * the specified radix. 667 * @throws NumberFormatException if the string does not contain a 668 * parsable {@code long}. 669 */ 670 public static long parseLong(String s, int radix) 671 throws NumberFormatException 672 { 673 if (s == null) { 674 throw new NumberFormatException("null"); 675 } 676 677 if (radix < Character.MIN_RADIX) { 678 throw new NumberFormatException("radix " + radix + 679 " less than Character.MIN_RADIX"); 680 } 681 if (radix > Character.MAX_RADIX) { 682 throw new NumberFormatException("radix " + radix + 683 " greater than Character.MAX_RADIX"); 684 } 685 686 boolean negative = false; 687 int i = 0, len = s.length(); 688 long limit = -Long.MAX_VALUE; 689 690 if (len > 0) { 691 char firstChar = s.charAt(0); 692 if (firstChar < '0') { // Possible leading "+" or "-" 693 if (firstChar == '-') { 694 negative = true; 695 limit = Long.MIN_VALUE; 696 } else if (firstChar != '+') { 697 throw NumberFormatException.forInputString(s); 698 } 699 700 if (len == 1) { // Cannot have lone "+" or "-" 701 throw NumberFormatException.forInputString(s); 702 } 703 i++; 704 } 705 long multmin = limit / radix; 706 long result = 0; 707 while (i < len) { 708 // Accumulating negatively avoids surprises near MAX_VALUE 709 int digit = Character.digit(s.charAt(i++),radix); 710 if (digit < 0 || result < multmin) { 711 throw NumberFormatException.forInputString(s); 712 } 713 result *= radix; 714 if (result < limit + digit) { 715 throw NumberFormatException.forInputString(s); 716 } 717 result -= digit; 718 } 719 return negative ? result : -result; 720 } else { 721 throw NumberFormatException.forInputString(s); 722 } 723 } 724 725 /** 726 * Parses the {@link CharSequence} argument as a signed {@code long} in 727 * the specified {@code radix}, beginning at the specified 728 * {@code beginIndex} and extending to {@code endIndex - 1}. 729 * 730 * <p>The method does not take steps to guard against the 731 * {@code CharSequence} being mutated while parsing. 732 * 733 * @param s the {@code CharSequence} containing the {@code long} 734 * representation to be parsed 735 * @param beginIndex the beginning index, inclusive. 736 * @param endIndex the ending index, exclusive. 737 * @param radix the radix to be used while parsing {@code s}. 738 * @return the signed {@code long} represented by the subsequence in 739 * the specified radix. 740 * @throws NullPointerException if {@code s} is null. 741 * @throws IndexOutOfBoundsException if {@code beginIndex} is 742 * negative, or if {@code beginIndex} is greater than 743 * {@code endIndex} or if {@code endIndex} is greater than 744 * {@code s.length()}. 745 * @throws NumberFormatException if the {@code CharSequence} does not 746 * contain a parsable {@code int} in the specified 747 * {@code radix}, or if {@code radix} is either smaller than 748 * {@link java.lang.Character#MIN_RADIX} or larger than 749 * {@link java.lang.Character#MAX_RADIX}. 750 * @since 1.9 751 */ 752 public static long parseLong(CharSequence s, int beginIndex, int endIndex, int radix) 753 throws NumberFormatException { 754 s = Objects.requireNonNull(s); 755 756 if (beginIndex < 0 || beginIndex > endIndex || endIndex > s.length()) { 757 throw new IndexOutOfBoundsException(); 758 } 759 if (radix < Character.MIN_RADIX) { 760 throw new NumberFormatException("radix " + radix + 761 " less than Character.MIN_RADIX"); 762 } 763 if (radix > Character.MAX_RADIX) { 764 throw new NumberFormatException("radix " + radix + 765 " greater than Character.MAX_RADIX"); 766 } 767 768 boolean negative = false; 769 int i = beginIndex; 770 long limit = -Long.MAX_VALUE; 771 772 if (i < endIndex) { 773 char firstChar = s.charAt(i); 774 if (firstChar < '0') { // Possible leading "+" or "-" 775 if (firstChar == '-') { 776 negative = true; 777 limit = Long.MIN_VALUE; 778 } else if (firstChar != '+') { 779 throw NumberFormatException.forCharSequence(s, beginIndex, 780 endIndex, i); 781 } 782 i++; 783 } 784 if (i >= endIndex) { // Cannot have lone "+", "-" or "" 785 throw NumberFormatException.forCharSequence(s, beginIndex, 786 endIndex, i); 787 } 788 long multmin = limit / radix; 789 long result = 0; 790 while (i < endIndex) { 791 // Accumulating negatively avoids surprises near MAX_VALUE 792 int digit = Character.digit(s.charAt(i), radix); 793 if (digit < 0 || result < multmin) { 794 throw NumberFormatException.forCharSequence(s, beginIndex, 795 endIndex, i); 796 } 797 result *= radix; 798 if (result < limit + digit) { 799 throw NumberFormatException.forCharSequence(s, beginIndex, 800 endIndex, i); 801 } 802 i++; 803 result -= digit; 804 } 805 return negative ? result : -result; 806 } else { 807 throw new NumberFormatException(""); 808 } 809 } 810 811 /** 812 * Parses the string argument as a signed decimal {@code long}. 813 * The characters in the string must all be decimal digits, except 814 * that the first character may be an ASCII minus sign {@code '-'} 815 * ({@code \u005Cu002D'}) to indicate a negative value or an 816 * ASCII plus sign {@code '+'} ({@code '\u005Cu002B'}) to 817 * indicate a positive value. The resulting {@code long} value is 818 * returned, exactly as if the argument and the radix {@code 10} 819 * were given as arguments to the {@link 820 * #parseLong(java.lang.String, int)} method. 821 * 822 * <p>Note that neither the character {@code L} 823 * ({@code '\u005Cu004C'}) nor {@code l} 824 * ({@code '\u005Cu006C'}) is permitted to appear at the end 825 * of the string as a type indicator, as would be permitted in 826 * Java programming language source code. 827 * 828 * @param s a {@code String} containing the {@code long} 829 * representation to be parsed 830 * @return the {@code long} represented by the argument in 831 * decimal. 832 * @throws NumberFormatException if the string does not contain a 833 * parsable {@code long}. 834 */ 835 public static long parseLong(String s) throws NumberFormatException { 836 return parseLong(s, 10); 837 } 838 839 /** 840 * Parses the string argument as an unsigned {@code long} in the 841 * radix specified by the second argument. An unsigned integer 842 * maps the values usually associated with negative numbers to 843 * positive numbers larger than {@code MAX_VALUE}. 844 * 845 * The characters in the string must all be digits of the 846 * specified radix (as determined by whether {@link 847 * java.lang.Character#digit(char, int)} returns a nonnegative 848 * value), except that the first character may be an ASCII plus 849 * sign {@code '+'} ({@code '\u005Cu002B'}). The resulting 850 * integer value is returned. 851 * 852 * <p>An exception of type {@code NumberFormatException} is 853 * thrown if any of the following situations occurs: 854 * <ul> 855 * <li>The first argument is {@code null} or is a string of 856 * length zero. 857 * 858 * <li>The radix is either smaller than 859 * {@link java.lang.Character#MIN_RADIX} or 860 * larger than {@link java.lang.Character#MAX_RADIX}. 861 * 862 * <li>Any character of the string is not a digit of the specified 863 * radix, except that the first character may be a plus sign 864 * {@code '+'} ({@code '\u005Cu002B'}) provided that the 865 * string is longer than length 1. 866 * 867 * <li>The value represented by the string is larger than the 868 * largest unsigned {@code long}, 2<sup>64</sup>-1. 869 * 870 * </ul> 871 * 872 * 873 * @param s the {@code String} containing the unsigned integer 874 * representation to be parsed 875 * @param radix the radix to be used while parsing {@code s}. 876 * @return the unsigned {@code long} represented by the string 877 * argument in the specified radix. 878 * @throws NumberFormatException if the {@code String} 879 * does not contain a parsable {@code long}. 880 * @since 1.8 881 */ 882 public static long parseUnsignedLong(String s, int radix) 883 throws NumberFormatException { 884 if (s == null) { 885 throw new NumberFormatException("null"); 886 } 887 888 int len = s.length(); 889 if (len > 0) { 890 char firstChar = s.charAt(0); 891 if (firstChar == '-') { 892 throw new 893 NumberFormatException(String.format("Illegal leading minus sign " + 894 "on unsigned string %s.", s)); 895 } else { 896 if (len <= 12 || // Long.MAX_VALUE in Character.MAX_RADIX is 13 digits 897 (radix == 10 && len <= 18) ) { // Long.MAX_VALUE in base 10 is 19 digits 898 return parseLong(s, radix); 899 } 900 901 // No need for range checks on len due to testing above. 902 long first = parseLong(s, 0, len - 1, radix); 903 int second = Character.digit(s.charAt(len - 1), radix); 904 if (second < 0) { 905 throw new NumberFormatException("Bad digit at end of " + s); 906 } 907 long result = first * radix + second; 908 909 /* 910 * Test leftmost bits of multiprecision extension of first*radix 911 * for overflow. The number of bits needed is defined by 912 * GUARD_BIT = ceil(log2(Character.MAX_RADIX)) + 1 = 7. Then 913 * int guard = radix*(int)(first >>> (64 - GUARD_BIT)) and 914 * overflow is tested by splitting guard in the ranges 915 * guard < 92, 92 <= guard < 128, and 128 <= guard, where 916 * 92 = 128 - Character.MAX_RADIX. Note that guard cannot take 917 * on a value which does not include a prime factor in the legal 918 * radix range. 919 */ 920 int guard = radix * (int) (first >>> 57); 921 if (guard >= 128 || 922 (result >= 0 && guard >= 128 - Character.MAX_RADIX)) { 923 /* 924 * For purposes of exposition, the programmatic statements 925 * below should be taken to be multi-precision, i.e., not 926 * subject to overflow. 927 * 928 * A) Condition guard >= 128: 929 * If guard >= 128 then first*radix >= 2^7 * 2^57 = 2^64 930 * hence always overflow. 931 * 932 * B) Condition guard < 92: 933 * Define left7 = first >>> 57. 934 * Given first = (left7 * 2^57) + (first & (2^57 - 1)) then 935 * result <= (radix*left7)*2^57 + radix*(2^57 - 1) + second. 936 * Thus if radix*left7 < 92, radix <= 36, and second < 36, 937 * then result < 92*2^57 + 36*(2^57 - 1) + 36 = 2^64 hence 938 * never overflow. 939 * 940 * C) Condition 92 <= guard < 128: 941 * first*radix + second >= radix*left7*2^57 + second 942 * so that first*radix + second >= 92*2^57 + 0 > 2^63 943 * 944 * D) Condition guard < 128: 945 * radix*first <= (radix*left7) * 2^57 + radix*(2^57 - 1) 946 * so 947 * radix*first + second <= (radix*left7) * 2^57 + radix*(2^57 - 1) + 36 948 * thus 949 * radix*first + second < 128 * 2^57 + 36*2^57 - radix + 36 950 * whence 951 * radix*first + second < 2^64 + 2^6*2^57 = 2^64 + 2^63 952 * 953 * E) Conditions C, D, and result >= 0: 954 * C and D combined imply the mathematical result 955 * 2^63 < first*radix + second < 2^64 + 2^63. The lower 956 * bound is therefore negative as a signed long, but the 957 * upper bound is too small to overflow again after the 958 * signed long overflows to positive above 2^64 - 1. Hence 959 * result >= 0 implies overflow given C and D. 960 */ 961 throw new NumberFormatException(String.format("String value %s exceeds " + 962 "range of unsigned long.", s)); 963 } 964 return result; 965 } 966 } else { 967 throw NumberFormatException.forInputString(s); 968 } 969 } 970 971 /** 972 * Parses the {@link CharSequence} argument as an unsigned {@code long} in 973 * the specified {@code radix}, beginning at the specified 974 * {@code beginIndex} and extending to {@code endIndex - 1}. 975 * 976 * <p>The method does not take steps to guard against the 977 * {@code CharSequence} being mutated while parsing. 978 * 979 * @param s the {@code CharSequence} containing the unsigned 980 * {@code long} representation to be parsed 981 * @param beginIndex the beginning index, inclusive. 982 * @param endIndex the ending index, exclusive. 983 * @param radix the radix to be used while parsing {@code s}. 984 * @return the unsigned {@code long} represented by the subsequence in 985 * the specified radix. 986 * @throws NullPointerException if {@code s} is null. 987 * @throws IndexOutOfBoundsException if {@code beginIndex} is 988 * negative, or if {@code beginIndex} is greater than 989 * {@code endIndex} or if {@code endIndex} is greater than 990 * {@code s.length()}. 991 * @throws NumberFormatException if the {@code CharSequence} does not 992 * contain a parsable unsigned {@code long} in the specified 993 * {@code radix}, or if {@code radix} is either smaller than 994 * {@link java.lang.Character#MIN_RADIX} or larger than 995 * {@link java.lang.Character#MAX_RADIX}. 996 * @since 1.9 997 */ 998 public static long parseUnsignedLong(CharSequence s, int beginIndex, int endIndex, int radix) 999 throws NumberFormatException { 1000 s = Objects.requireNonNull(s); 1001 1002 if (beginIndex < 0 || beginIndex > endIndex || endIndex > s.length()) { 1003 throw new IndexOutOfBoundsException(); 1004 } 1005 int start = beginIndex, len = endIndex - beginIndex; 1006 1007 if (len > 0) { 1008 char firstChar = s.charAt(start); 1009 if (firstChar == '-') { 1010 throw new NumberFormatException(String.format("Illegal leading minus sign " + 1011 "on unsigned string %s.", s.subSequence(start, start + len))); 1012 } else { 1013 if (len <= 12 || // Long.MAX_VALUE in Character.MAX_RADIX is 13 digits 1014 (radix == 10 && len <= 18) ) { // Long.MAX_VALUE in base 10 is 19 digits 1015 return parseLong(s, start, start + len, radix); 1016 } 1017 1018 // No need for range checks on end due to testing above. 1019 long first = parseLong(s, start, start + len - 1, radix); 1020 int second = Character.digit(s.charAt(start + len - 1), radix); 1021 if (second < 0) { 1022 throw new NumberFormatException("Bad digit at end of " + 1023 s.subSequence(start, start + len)); 1024 } 1025 long result = first * radix + second; 1026 1027 /* 1028 * Test leftmost bits of multiprecision extension of first*radix 1029 * for overflow. The number of bits needed is defined by 1030 * GUARD_BIT = ceil(log2(Character.MAX_RADIX)) + 1 = 7. Then 1031 * int guard = radix*(int)(first >>> (64 - GUARD_BIT)) and 1032 * overflow is tested by splitting guard in the ranges 1033 * guard < 92, 92 <= guard < 128, and 128 <= guard, where 1034 * 92 = 128 - Character.MAX_RADIX. Note that guard cannot take 1035 * on a value which does not include a prime factor in the legal 1036 * radix range. 1037 */ 1038 int guard = radix * (int) (first >>> 57); 1039 if (guard >= 128 || 1040 (result >= 0 && guard >= 128 - Character.MAX_RADIX)) { 1041 /* 1042 * For purposes of exposition, the programmatic statements 1043 * below should be taken to be multi-precision, i.e., not 1044 * subject to overflow. 1045 * 1046 * A) Condition guard >= 128: 1047 * If guard >= 128 then first*radix >= 2^7 * 2^57 = 2^64 1048 * hence always overflow. 1049 * 1050 * B) Condition guard < 92: 1051 * Define left7 = first >>> 57. 1052 * Given first = (left7 * 2^57) + (first & (2^57 - 1)) then 1053 * result <= (radix*left7)*2^57 + radix*(2^57 - 1) + second. 1054 * Thus if radix*left7 < 92, radix <= 36, and second < 36, 1055 * then result < 92*2^57 + 36*(2^57 - 1) + 36 = 2^64 hence 1056 * never overflow. 1057 * 1058 * C) Condition 92 <= guard < 128: 1059 * first*radix + second >= radix*left7*2^57 + second 1060 * so that first*radix + second >= 92*2^57 + 0 > 2^63 1061 * 1062 * D) Condition guard < 128: 1063 * radix*first <= (radix*left7) * 2^57 + radix*(2^57 - 1) 1064 * so 1065 * radix*first + second <= (radix*left7) * 2^57 + radix*(2^57 - 1) + 36 1066 * thus 1067 * radix*first + second < 128 * 2^57 + 36*2^57 - radix + 36 1068 * whence 1069 * radix*first + second < 2^64 + 2^6*2^57 = 2^64 + 2^63 1070 * 1071 * E) Conditions C, D, and result >= 0: 1072 * C and D combined imply the mathematical result 1073 * 2^63 < first*radix + second < 2^64 + 2^63. The lower 1074 * bound is therefore negative as a signed long, but the 1075 * upper bound is too small to overflow again after the 1076 * signed long overflows to positive above 2^64 - 1. Hence 1077 * result >= 0 implies overflow given C and D. 1078 */ 1079 throw new NumberFormatException(String.format("String value %s exceeds " + 1080 "range of unsigned long.", s.subSequence(start, start + len))); 1081 } 1082 return result; 1083 } 1084 } else { 1085 throw NumberFormatException.forInputString(""); 1086 } 1087 } 1088 1089 /** 1090 * Parses the string argument as an unsigned decimal {@code long}. The 1091 * characters in the string must all be decimal digits, except 1092 * that the first character may be an ASCII plus sign {@code 1093 * '+'} ({@code '\u005Cu002B'}). The resulting integer value 1094 * is returned, exactly as if the argument and the radix 10 were 1095 * given as arguments to the {@link 1096 * #parseUnsignedLong(java.lang.String, int)} method. 1097 * 1098 * @param s a {@code String} containing the unsigned {@code long} 1099 * representation to be parsed 1100 * @return the unsigned {@code long} value represented by the decimal string argument 1101 * @throws NumberFormatException if the string does not contain a 1102 * parsable unsigned integer. 1103 * @since 1.8 1104 */ 1105 public static long parseUnsignedLong(String s) throws NumberFormatException { 1106 return parseUnsignedLong(s, 10); 1107 } 1108 1109 /** 1110 * Returns a {@code Long} object holding the value 1111 * extracted from the specified {@code String} when parsed 1112 * with the radix given by the second argument. The first 1113 * argument is interpreted as representing a signed 1114 * {@code long} in the radix specified by the second 1115 * argument, exactly as if the arguments were given to the {@link 1116 * #parseLong(java.lang.String, int)} method. The result is a 1117 * {@code Long} object that represents the {@code long} 1118 * value specified by the string. 1119 * 1120 * <p>In other words, this method returns a {@code Long} object equal 1121 * to the value of: 1122 * 1123 * <blockquote> 1124 * {@code new Long(Long.parseLong(s, radix))} 1125 * </blockquote> 1126 * 1127 * @param s the string to be parsed 1128 * @param radix the radix to be used in interpreting {@code s} 1129 * @return a {@code Long} object holding the value 1130 * represented by the string argument in the specified 1131 * radix. 1132 * @throws NumberFormatException If the {@code String} does not 1133 * contain a parsable {@code long}. 1134 */ 1135 public static Long valueOf(String s, int radix) throws NumberFormatException { 1136 return Long.valueOf(parseLong(s, radix)); 1137 } 1138 1139 /** 1140 * Returns a {@code Long} object holding the value 1141 * of the specified {@code String}. The argument is 1142 * interpreted as representing a signed decimal {@code long}, 1143 * exactly as if the argument were given to the {@link 1144 * #parseLong(java.lang.String)} method. The result is a 1145 * {@code Long} object that represents the integer value 1146 * specified by the string. 1147 * 1148 * <p>In other words, this method returns a {@code Long} object 1149 * equal to the value of: 1150 * 1151 * <blockquote> 1152 * {@code new Long(Long.parseLong(s))} 1153 * </blockquote> 1154 * 1155 * @param s the string to be parsed. 1156 * @return a {@code Long} object holding the value 1157 * represented by the string argument. 1158 * @throws NumberFormatException If the string cannot be parsed 1159 * as a {@code long}. 1160 */ 1161 public static Long valueOf(String s) throws NumberFormatException 1162 { 1163 return Long.valueOf(parseLong(s, 10)); 1164 } 1165 1166 private static class LongCache { 1167 private LongCache(){} 1168 1169 static final Long cache[] = new Long[-(-128) + 127 + 1]; 1170 1171 static { 1172 for(int i = 0; i < cache.length; i++) 1173 cache[i] = new Long(i - 128); 1174 } 1175 } 1176 1177 /** 1178 * Returns a {@code Long} instance representing the specified 1179 * {@code long} value. 1180 * If a new {@code Long} instance is not required, this method 1181 * should generally be used in preference to the constructor 1182 * {@link #Long(long)}, as this method is likely to yield 1183 * significantly better space and time performance by caching 1184 * frequently requested values. 1185 * 1186 * Note that unlike the {@linkplain Integer#valueOf(int) 1187 * corresponding method} in the {@code Integer} class, this method 1188 * is <em>not</em> required to cache values within a particular 1189 * range. 1190 * 1191 * @param l a long value. 1192 * @return a {@code Long} instance representing {@code l}. 1193 * @since 1.5 1194 */ 1195 @HotSpotIntrinsicCandidate 1196 public static Long valueOf(long l) { 1197 final int offset = 128; 1198 if (l >= -128 && l <= 127) { // will cache 1199 return LongCache.cache[(int)l + offset]; 1200 } 1201 return new Long(l); 1202 } 1203 1204 /** 1205 * Decodes a {@code String} into a {@code Long}. 1206 * Accepts decimal, hexadecimal, and octal numbers given by the 1207 * following grammar: 1208 * 1209 * <blockquote> 1210 * <dl> 1211 * <dt><i>DecodableString:</i> 1212 * <dd><i>Sign<sub>opt</sub> DecimalNumeral</i> 1213 * <dd><i>Sign<sub>opt</sub></i> {@code 0x} <i>HexDigits</i> 1214 * <dd><i>Sign<sub>opt</sub></i> {@code 0X} <i>HexDigits</i> 1215 * <dd><i>Sign<sub>opt</sub></i> {@code #} <i>HexDigits</i> 1216 * <dd><i>Sign<sub>opt</sub></i> {@code 0} <i>OctalDigits</i> 1217 * 1218 * <dt><i>Sign:</i> 1219 * <dd>{@code -} 1220 * <dd>{@code +} 1221 * </dl> 1222 * </blockquote> 1223 * 1224 * <i>DecimalNumeral</i>, <i>HexDigits</i>, and <i>OctalDigits</i> 1225 * are as defined in section 3.10.1 of 1226 * <cite>The Java™ Language Specification</cite>, 1227 * except that underscores are not accepted between digits. 1228 * 1229 * <p>The sequence of characters following an optional 1230 * sign and/or radix specifier ("{@code 0x}", "{@code 0X}", 1231 * "{@code #}", or leading zero) is parsed as by the {@code 1232 * Long.parseLong} method with the indicated radix (10, 16, or 8). 1233 * This sequence of characters must represent a positive value or 1234 * a {@link NumberFormatException} will be thrown. The result is 1235 * negated if first character of the specified {@code String} is 1236 * the minus sign. No whitespace characters are permitted in the 1237 * {@code String}. 1238 * 1239 * @param nm the {@code String} to decode. 1240 * @return a {@code Long} object holding the {@code long} 1241 * value represented by {@code nm} 1242 * @throws NumberFormatException if the {@code String} does not 1243 * contain a parsable {@code long}. 1244 * @see java.lang.Long#parseLong(String, int) 1245 * @since 1.2 1246 */ 1247 public static Long decode(String nm) throws NumberFormatException { 1248 int radix = 10; 1249 int index = 0; 1250 boolean negative = false; 1251 Long result; 1252 1253 if (nm.length() == 0) 1254 throw new NumberFormatException("Zero length string"); 1255 char firstChar = nm.charAt(0); 1256 // Handle sign, if present 1257 if (firstChar == '-') { 1258 negative = true; 1259 index++; 1260 } else if (firstChar == '+') 1261 index++; 1262 1263 // Handle radix specifier, if present 1264 if (nm.startsWith("0x", index) || nm.startsWith("0X", index)) { 1265 index += 2; 1266 radix = 16; 1267 } 1268 else if (nm.startsWith("#", index)) { 1269 index ++; 1270 radix = 16; 1271 } 1272 else if (nm.startsWith("0", index) && nm.length() > 1 + index) { 1273 index ++; 1274 radix = 8; 1275 } 1276 1277 if (nm.startsWith("-", index) || nm.startsWith("+", index)) 1278 throw new NumberFormatException("Sign character in wrong position"); 1279 1280 try { 1281 result = Long.valueOf(nm.substring(index), radix); 1282 result = negative ? Long.valueOf(-result.longValue()) : result; 1283 } catch (NumberFormatException e) { 1284 // If number is Long.MIN_VALUE, we'll end up here. The next line 1285 // handles this case, and causes any genuine format error to be 1286 // rethrown. 1287 String constant = negative ? ("-" + nm.substring(index)) 1288 : nm.substring(index); 1289 result = Long.valueOf(constant, radix); 1290 } 1291 return result; 1292 } 1293 1294 /** 1295 * The value of the {@code Long}. 1296 * 1297 * @serial 1298 */ 1299 private final long value; 1300 1301 /** 1302 * Constructs a newly allocated {@code Long} object that 1303 * represents the specified {@code long} argument. 1304 * 1305 * @param value the value to be represented by the 1306 * {@code Long} object. 1307 */ 1308 public Long(long value) { 1309 this.value = value; 1310 } 1311 1312 /** 1313 * Constructs a newly allocated {@code Long} object that 1314 * represents the {@code long} value indicated by the 1315 * {@code String} parameter. The string is converted to a 1316 * {@code long} value in exactly the manner used by the 1317 * {@code parseLong} method for radix 10. 1318 * 1319 * @param s the {@code String} to be converted to a 1320 * {@code Long}. 1321 * @throws NumberFormatException if the {@code String} does not 1322 * contain a parsable {@code long}. 1323 * @see java.lang.Long#parseLong(java.lang.String, int) 1324 */ 1325 public Long(String s) throws NumberFormatException { 1326 this.value = parseLong(s, 10); 1327 } 1328 1329 /** 1330 * Returns the value of this {@code Long} as a {@code byte} after 1331 * a narrowing primitive conversion. 1332 * @jls 5.1.3 Narrowing Primitive Conversions 1333 */ 1334 public byte byteValue() { 1335 return (byte)value; 1336 } 1337 1338 /** 1339 * Returns the value of this {@code Long} as a {@code short} after 1340 * a narrowing primitive conversion. 1341 * @jls 5.1.3 Narrowing Primitive Conversions 1342 */ 1343 public short shortValue() { 1344 return (short)value; 1345 } 1346 1347 /** 1348 * Returns the value of this {@code Long} as an {@code int} after 1349 * a narrowing primitive conversion. 1350 * @jls 5.1.3 Narrowing Primitive Conversions 1351 */ 1352 public int intValue() { 1353 return (int)value; 1354 } 1355 1356 /** 1357 * Returns the value of this {@code Long} as a 1358 * {@code long} value. 1359 */ 1360 @HotSpotIntrinsicCandidate 1361 public long longValue() { 1362 return value; 1363 } 1364 1365 /** 1366 * Returns the value of this {@code Long} as a {@code float} after 1367 * a widening primitive conversion. 1368 * @jls 5.1.2 Widening Primitive Conversions 1369 */ 1370 public float floatValue() { 1371 return (float)value; 1372 } 1373 1374 /** 1375 * Returns the value of this {@code Long} as a {@code double} 1376 * after a widening primitive conversion. 1377 * @jls 5.1.2 Widening Primitive Conversions 1378 */ 1379 public double doubleValue() { 1380 return (double)value; 1381 } 1382 1383 /** 1384 * Returns a {@code String} object representing this 1385 * {@code Long}'s value. The value is converted to signed 1386 * decimal representation and returned as a string, exactly as if 1387 * the {@code long} value were given as an argument to the 1388 * {@link java.lang.Long#toString(long)} method. 1389 * 1390 * @return a string representation of the value of this object in 1391 * base 10. 1392 */ 1393 public String toString() { 1394 return toString(value); 1395 } 1396 1397 /** 1398 * Returns a hash code for this {@code Long}. The result is 1399 * the exclusive OR of the two halves of the primitive 1400 * {@code long} value held by this {@code Long} 1401 * object. That is, the hashcode is the value of the expression: 1402 * 1403 * <blockquote> 1404 * {@code (int)(this.longValue()^(this.longValue()>>>32))} 1405 * </blockquote> 1406 * 1407 * @return a hash code value for this object. 1408 */ 1409 @Override 1410 public int hashCode() { 1411 return Long.hashCode(value); 1412 } 1413 1414 /** 1415 * Returns a hash code for a {@code long} value; compatible with 1416 * {@code Long.hashCode()}. 1417 * 1418 * @param value the value to hash 1419 * @return a hash code value for a {@code long} value. 1420 * @since 1.8 1421 */ 1422 public static int hashCode(long value) { 1423 return (int)(value ^ (value >>> 32)); 1424 } 1425 1426 /** 1427 * Compares this object to the specified object. The result is 1428 * {@code true} if and only if the argument is not 1429 * {@code null} and is a {@code Long} object that 1430 * contains the same {@code long} value as this object. 1431 * 1432 * @param obj the object to compare with. 1433 * @return {@code true} if the objects are the same; 1434 * {@code false} otherwise. 1435 */ 1436 public boolean equals(Object obj) { 1437 if (obj instanceof Long) { 1438 return value == ((Long)obj).longValue(); 1439 } 1440 return false; 1441 } 1442 1443 /** 1444 * Determines the {@code long} value of the system property 1445 * with the specified name. 1446 * 1447 * <p>The first argument is treated as the name of a system 1448 * property. System properties are accessible through the {@link 1449 * java.lang.System#getProperty(java.lang.String)} method. The 1450 * string value of this property is then interpreted as a {@code 1451 * long} value using the grammar supported by {@link Long#decode decode} 1452 * and a {@code Long} object representing this value is returned. 1453 * 1454 * <p>If there is no property with the specified name, if the 1455 * specified name is empty or {@code null}, or if the property 1456 * does not have the correct numeric format, then {@code null} is 1457 * returned. 1458 * 1459 * <p>In other words, this method returns a {@code Long} object 1460 * equal to the value of: 1461 * 1462 * <blockquote> 1463 * {@code getLong(nm, null)} 1464 * </blockquote> 1465 * 1466 * @param nm property name. 1467 * @return the {@code Long} value of the property. 1468 * @throws SecurityException for the same reasons as 1469 * {@link System#getProperty(String) System.getProperty} 1470 * @see java.lang.System#getProperty(java.lang.String) 1471 * @see java.lang.System#getProperty(java.lang.String, java.lang.String) 1472 */ 1473 public static Long getLong(String nm) { 1474 return getLong(nm, null); 1475 } 1476 1477 /** 1478 * Determines the {@code long} value of the system property 1479 * with the specified name. 1480 * 1481 * <p>The first argument is treated as the name of a system 1482 * property. System properties are accessible through the {@link 1483 * java.lang.System#getProperty(java.lang.String)} method. The 1484 * string value of this property is then interpreted as a {@code 1485 * long} value using the grammar supported by {@link Long#decode decode} 1486 * and a {@code Long} object representing this value is returned. 1487 * 1488 * <p>The second argument is the default value. A {@code Long} object 1489 * that represents the value of the second argument is returned if there 1490 * is no property of the specified name, if the property does not have 1491 * the correct numeric format, or if the specified name is empty or null. 1492 * 1493 * <p>In other words, this method returns a {@code Long} object equal 1494 * to the value of: 1495 * 1496 * <blockquote> 1497 * {@code getLong(nm, new Long(val))} 1498 * </blockquote> 1499 * 1500 * but in practice it may be implemented in a manner such as: 1501 * 1502 * <blockquote><pre> 1503 * Long result = getLong(nm, null); 1504 * return (result == null) ? new Long(val) : result; 1505 * </pre></blockquote> 1506 * 1507 * to avoid the unnecessary allocation of a {@code Long} object when 1508 * the default value is not needed. 1509 * 1510 * @param nm property name. 1511 * @param val default value. 1512 * @return the {@code Long} value of the property. 1513 * @throws SecurityException for the same reasons as 1514 * {@link System#getProperty(String) System.getProperty} 1515 * @see java.lang.System#getProperty(java.lang.String) 1516 * @see java.lang.System#getProperty(java.lang.String, java.lang.String) 1517 */ 1518 public static Long getLong(String nm, long val) { 1519 Long result = Long.getLong(nm, null); 1520 return (result == null) ? Long.valueOf(val) : result; 1521 } 1522 1523 /** 1524 * Returns the {@code long} value of the system property with 1525 * the specified name. The first argument is treated as the name 1526 * of a system property. System properties are accessible through 1527 * the {@link java.lang.System#getProperty(java.lang.String)} 1528 * method. The string value of this property is then interpreted 1529 * as a {@code long} value, as per the 1530 * {@link Long#decode decode} method, and a {@code Long} object 1531 * representing this value is returned; in summary: 1532 * 1533 * <ul> 1534 * <li>If the property value begins with the two ASCII characters 1535 * {@code 0x} or the ASCII character {@code #}, not followed by 1536 * a minus sign, then the rest of it is parsed as a hexadecimal integer 1537 * exactly as for the method {@link #valueOf(java.lang.String, int)} 1538 * with radix 16. 1539 * <li>If the property value begins with the ASCII character 1540 * {@code 0} followed by another character, it is parsed as 1541 * an octal integer exactly as by the method {@link 1542 * #valueOf(java.lang.String, int)} with radix 8. 1543 * <li>Otherwise the property value is parsed as a decimal 1544 * integer exactly as by the method 1545 * {@link #valueOf(java.lang.String, int)} with radix 10. 1546 * </ul> 1547 * 1548 * <p>Note that, in every case, neither {@code L} 1549 * ({@code '\u005Cu004C'}) nor {@code l} 1550 * ({@code '\u005Cu006C'}) is permitted to appear at the end 1551 * of the property value as a type indicator, as would be 1552 * permitted in Java programming language source code. 1553 * 1554 * <p>The second argument is the default value. The default value is 1555 * returned if there is no property of the specified name, if the 1556 * property does not have the correct numeric format, or if the 1557 * specified name is empty or {@code null}. 1558 * 1559 * @param nm property name. 1560 * @param val default value. 1561 * @return the {@code Long} value of the property. 1562 * @throws SecurityException for the same reasons as 1563 * {@link System#getProperty(String) System.getProperty} 1564 * @see System#getProperty(java.lang.String) 1565 * @see System#getProperty(java.lang.String, java.lang.String) 1566 */ 1567 public static Long getLong(String nm, Long val) { 1568 String v = null; 1569 try { 1570 v = System.getProperty(nm); 1571 } catch (IllegalArgumentException | NullPointerException e) { 1572 } 1573 if (v != null) { 1574 try { 1575 return Long.decode(v); 1576 } catch (NumberFormatException e) { 1577 } 1578 } 1579 return val; 1580 } 1581 1582 /** 1583 * Compares two {@code Long} objects numerically. 1584 * 1585 * @param anotherLong the {@code Long} to be compared. 1586 * @return the value {@code 0} if this {@code Long} is 1587 * equal to the argument {@code Long}; a value less than 1588 * {@code 0} if this {@code Long} is numerically less 1589 * than the argument {@code Long}; and a value greater 1590 * than {@code 0} if this {@code Long} is numerically 1591 * greater than the argument {@code Long} (signed 1592 * comparison). 1593 * @since 1.2 1594 */ 1595 public int compareTo(Long anotherLong) { 1596 return compare(this.value, anotherLong.value); 1597 } 1598 1599 /** 1600 * Compares two {@code long} values numerically. 1601 * The value returned is identical to what would be returned by: 1602 * <pre> 1603 * Long.valueOf(x).compareTo(Long.valueOf(y)) 1604 * </pre> 1605 * 1606 * @param x the first {@code long} to compare 1607 * @param y the second {@code long} to compare 1608 * @return the value {@code 0} if {@code x == y}; 1609 * a value less than {@code 0} if {@code x < y}; and 1610 * a value greater than {@code 0} if {@code x > y} 1611 * @since 1.7 1612 */ 1613 public static int compare(long x, long y) { 1614 return (x < y) ? -1 : ((x == y) ? 0 : 1); 1615 } 1616 1617 /** 1618 * Compares two {@code long} values numerically treating the values 1619 * as unsigned. 1620 * 1621 * @param x the first {@code long} to compare 1622 * @param y the second {@code long} to compare 1623 * @return the value {@code 0} if {@code x == y}; a value less 1624 * than {@code 0} if {@code x < y} as unsigned values; and 1625 * a value greater than {@code 0} if {@code x > y} as 1626 * unsigned values 1627 * @since 1.8 1628 */ 1629 public static int compareUnsigned(long x, long y) { 1630 return compare(x + MIN_VALUE, y + MIN_VALUE); 1631 } 1632 1633 1634 /** 1635 * Returns the unsigned quotient of dividing the first argument by 1636 * the second where each argument and the result is interpreted as 1637 * an unsigned value. 1638 * 1639 * <p>Note that in two's complement arithmetic, the three other 1640 * basic arithmetic operations of add, subtract, and multiply are 1641 * bit-wise identical if the two operands are regarded as both 1642 * being signed or both being unsigned. Therefore separate {@code 1643 * addUnsigned}, etc. methods are not provided. 1644 * 1645 * @param dividend the value to be divided 1646 * @param divisor the value doing the dividing 1647 * @return the unsigned quotient of the first argument divided by 1648 * the second argument 1649 * @see #remainderUnsigned 1650 * @since 1.8 1651 */ 1652 public static long divideUnsigned(long dividend, long divisor) { 1653 if (divisor < 0L) { // signed comparison 1654 // Answer must be 0 or 1 depending on relative magnitude 1655 // of dividend and divisor. 1656 return (compareUnsigned(dividend, divisor)) < 0 ? 0L :1L; 1657 } 1658 1659 if (dividend > 0) // Both inputs non-negative 1660 return dividend/divisor; 1661 else { 1662 /* 1663 * For simple code, leveraging BigInteger. Longer and faster 1664 * code written directly in terms of operations on longs is 1665 * possible; see "Hacker's Delight" for divide and remainder 1666 * algorithms. 1667 */ 1668 return toUnsignedBigInteger(dividend). 1669 divide(toUnsignedBigInteger(divisor)).longValue(); 1670 } 1671 } 1672 1673 /** 1674 * Returns the unsigned remainder from dividing the first argument 1675 * by the second where each argument and the result is interpreted 1676 * as an unsigned value. 1677 * 1678 * @param dividend the value to be divided 1679 * @param divisor the value doing the dividing 1680 * @return the unsigned remainder of the first argument divided by 1681 * the second argument 1682 * @see #divideUnsigned 1683 * @since 1.8 1684 */ 1685 public static long remainderUnsigned(long dividend, long divisor) { 1686 if (dividend > 0 && divisor > 0) { // signed comparisons 1687 return dividend % divisor; 1688 } else { 1689 if (compareUnsigned(dividend, divisor) < 0) // Avoid explicit check for 0 divisor 1690 return dividend; 1691 else 1692 return toUnsignedBigInteger(dividend). 1693 remainder(toUnsignedBigInteger(divisor)).longValue(); 1694 } 1695 } 1696 1697 // Bit Twiddling 1698 1699 /** 1700 * The number of bits used to represent a {@code long} value in two's 1701 * complement binary form. 1702 * 1703 * @since 1.5 1704 */ 1705 @Native public static final int SIZE = 64; 1706 1707 /** 1708 * The number of bytes used to represent a {@code long} value in two's 1709 * complement binary form. 1710 * 1711 * @since 1.8 1712 */ 1713 public static final int BYTES = SIZE / Byte.SIZE; 1714 1715 /** 1716 * Returns a {@code long} value with at most a single one-bit, in the 1717 * position of the highest-order ("leftmost") one-bit in the specified 1718 * {@code long} value. Returns zero if the specified value has no 1719 * one-bits in its two's complement binary representation, that is, if it 1720 * is equal to zero. 1721 * 1722 * @param i the value whose highest one bit is to be computed 1723 * @return a {@code long} value with a single one-bit, in the position 1724 * of the highest-order one-bit in the specified value, or zero if 1725 * the specified value is itself equal to zero. 1726 * @since 1.5 1727 */ 1728 public static long highestOneBit(long i) { 1729 // HD, Figure 3-1 1730 i |= (i >> 1); 1731 i |= (i >> 2); 1732 i |= (i >> 4); 1733 i |= (i >> 8); 1734 i |= (i >> 16); 1735 i |= (i >> 32); 1736 return i - (i >>> 1); 1737 } 1738 1739 /** 1740 * Returns a {@code long} value with at most a single one-bit, in the 1741 * position of the lowest-order ("rightmost") one-bit in the specified 1742 * {@code long} value. Returns zero if the specified value has no 1743 * one-bits in its two's complement binary representation, that is, if it 1744 * is equal to zero. 1745 * 1746 * @param i the value whose lowest one bit is to be computed 1747 * @return a {@code long} value with a single one-bit, in the position 1748 * of the lowest-order one-bit in the specified value, or zero if 1749 * the specified value is itself equal to zero. 1750 * @since 1.5 1751 */ 1752 public static long lowestOneBit(long i) { 1753 // HD, Section 2-1 1754 return i & -i; 1755 } 1756 1757 /** 1758 * Returns the number of zero bits preceding the highest-order 1759 * ("leftmost") one-bit in the two's complement binary representation 1760 * of the specified {@code long} value. Returns 64 if the 1761 * specified value has no one-bits in its two's complement representation, 1762 * in other words if it is equal to zero. 1763 * 1764 * <p>Note that this method is closely related to the logarithm base 2. 1765 * For all positive {@code long} values x: 1766 * <ul> 1767 * <li>floor(log<sub>2</sub>(x)) = {@code 63 - numberOfLeadingZeros(x)} 1768 * <li>ceil(log<sub>2</sub>(x)) = {@code 64 - numberOfLeadingZeros(x - 1)} 1769 * </ul> 1770 * 1771 * @param i the value whose number of leading zeros is to be computed 1772 * @return the number of zero bits preceding the highest-order 1773 * ("leftmost") one-bit in the two's complement binary representation 1774 * of the specified {@code long} value, or 64 if the value 1775 * is equal to zero. 1776 * @since 1.5 1777 */ 1778 @HotSpotIntrinsicCandidate 1779 public static int numberOfLeadingZeros(long i) { 1780 // HD, Figure 5-6 1781 if (i == 0) 1782 return 64; 1783 int n = 1; 1784 int x = (int)(i >>> 32); 1785 if (x == 0) { n += 32; x = (int)i; } 1786 if (x >>> 16 == 0) { n += 16; x <<= 16; } 1787 if (x >>> 24 == 0) { n += 8; x <<= 8; } 1788 if (x >>> 28 == 0) { n += 4; x <<= 4; } 1789 if (x >>> 30 == 0) { n += 2; x <<= 2; } 1790 n -= x >>> 31; 1791 return n; 1792 } 1793 1794 /** 1795 * Returns the number of zero bits following the lowest-order ("rightmost") 1796 * one-bit in the two's complement binary representation of the specified 1797 * {@code long} value. Returns 64 if the specified value has no 1798 * one-bits in its two's complement representation, in other words if it is 1799 * equal to zero. 1800 * 1801 * @param i the value whose number of trailing zeros is to be computed 1802 * @return the number of zero bits following the lowest-order ("rightmost") 1803 * one-bit in the two's complement binary representation of the 1804 * specified {@code long} value, or 64 if the value is equal 1805 * to zero. 1806 * @since 1.5 1807 */ 1808 @HotSpotIntrinsicCandidate 1809 public static int numberOfTrailingZeros(long i) { 1810 // HD, Figure 5-14 1811 int x, y; 1812 if (i == 0) return 64; 1813 int n = 63; 1814 y = (int)i; if (y != 0) { n = n -32; x = y; } else x = (int)(i>>>32); 1815 y = x <<16; if (y != 0) { n = n -16; x = y; } 1816 y = x << 8; if (y != 0) { n = n - 8; x = y; } 1817 y = x << 4; if (y != 0) { n = n - 4; x = y; } 1818 y = x << 2; if (y != 0) { n = n - 2; x = y; } 1819 return n - ((x << 1) >>> 31); 1820 } 1821 1822 /** 1823 * Returns the number of one-bits in the two's complement binary 1824 * representation of the specified {@code long} value. This function is 1825 * sometimes referred to as the <i>population count</i>. 1826 * 1827 * @param i the value whose bits are to be counted 1828 * @return the number of one-bits in the two's complement binary 1829 * representation of the specified {@code long} value. 1830 * @since 1.5 1831 */ 1832 @HotSpotIntrinsicCandidate 1833 public static int bitCount(long i) { 1834 // HD, Figure 5-2 1835 i = i - ((i >>> 1) & 0x5555555555555555L); 1836 i = (i & 0x3333333333333333L) + ((i >>> 2) & 0x3333333333333333L); 1837 i = (i + (i >>> 4)) & 0x0f0f0f0f0f0f0f0fL; 1838 i = i + (i >>> 8); 1839 i = i + (i >>> 16); 1840 i = i + (i >>> 32); 1841 return (int)i & 0x7f; 1842 } 1843 1844 /** 1845 * Returns the value obtained by rotating the two's complement binary 1846 * representation of the specified {@code long} value left by the 1847 * specified number of bits. (Bits shifted out of the left hand, or 1848 * high-order, side reenter on the right, or low-order.) 1849 * 1850 * <p>Note that left rotation with a negative distance is equivalent to 1851 * right rotation: {@code rotateLeft(val, -distance) == rotateRight(val, 1852 * distance)}. Note also that rotation by any multiple of 64 is a 1853 * no-op, so all but the last six bits of the rotation distance can be 1854 * ignored, even if the distance is negative: {@code rotateLeft(val, 1855 * distance) == rotateLeft(val, distance & 0x3F)}. 1856 * 1857 * @param i the value whose bits are to be rotated left 1858 * @param distance the number of bit positions to rotate left 1859 * @return the value obtained by rotating the two's complement binary 1860 * representation of the specified {@code long} value left by the 1861 * specified number of bits. 1862 * @since 1.5 1863 */ 1864 public static long rotateLeft(long i, int distance) { 1865 return (i << distance) | (i >>> -distance); 1866 } 1867 1868 /** 1869 * Returns the value obtained by rotating the two's complement binary 1870 * representation of the specified {@code long} value right by the 1871 * specified number of bits. (Bits shifted out of the right hand, or 1872 * low-order, side reenter on the left, or high-order.) 1873 * 1874 * <p>Note that right rotation with a negative distance is equivalent to 1875 * left rotation: {@code rotateRight(val, -distance) == rotateLeft(val, 1876 * distance)}. Note also that rotation by any multiple of 64 is a 1877 * no-op, so all but the last six bits of the rotation distance can be 1878 * ignored, even if the distance is negative: {@code rotateRight(val, 1879 * distance) == rotateRight(val, distance & 0x3F)}. 1880 * 1881 * @param i the value whose bits are to be rotated right 1882 * @param distance the number of bit positions to rotate right 1883 * @return the value obtained by rotating the two's complement binary 1884 * representation of the specified {@code long} value right by the 1885 * specified number of bits. 1886 * @since 1.5 1887 */ 1888 public static long rotateRight(long i, int distance) { 1889 return (i >>> distance) | (i << -distance); 1890 } 1891 1892 /** 1893 * Returns the value obtained by reversing the order of the bits in the 1894 * two's complement binary representation of the specified {@code long} 1895 * value. 1896 * 1897 * @param i the value to be reversed 1898 * @return the value obtained by reversing order of the bits in the 1899 * specified {@code long} value. 1900 * @since 1.5 1901 */ 1902 public static long reverse(long i) { 1903 // HD, Figure 7-1 1904 i = (i & 0x5555555555555555L) << 1 | (i >>> 1) & 0x5555555555555555L; 1905 i = (i & 0x3333333333333333L) << 2 | (i >>> 2) & 0x3333333333333333L; 1906 i = (i & 0x0f0f0f0f0f0f0f0fL) << 4 | (i >>> 4) & 0x0f0f0f0f0f0f0f0fL; 1907 i = (i & 0x00ff00ff00ff00ffL) << 8 | (i >>> 8) & 0x00ff00ff00ff00ffL; 1908 i = (i << 48) | ((i & 0xffff0000L) << 16) | 1909 ((i >>> 16) & 0xffff0000L) | (i >>> 48); 1910 return i; 1911 } 1912 1913 /** 1914 * Returns the signum function of the specified {@code long} value. (The 1915 * return value is -1 if the specified value is negative; 0 if the 1916 * specified value is zero; and 1 if the specified value is positive.) 1917 * 1918 * @param i the value whose signum is to be computed 1919 * @return the signum function of the specified {@code long} value. 1920 * @since 1.5 1921 */ 1922 public static int signum(long i) { 1923 // HD, Section 2-7 1924 return (int) ((i >> 63) | (-i >>> 63)); 1925 } 1926 1927 /** 1928 * Returns the value obtained by reversing the order of the bytes in the 1929 * two's complement representation of the specified {@code long} value. 1930 * 1931 * @param i the value whose bytes are to be reversed 1932 * @return the value obtained by reversing the bytes in the specified 1933 * {@code long} value. 1934 * @since 1.5 1935 */ 1936 @HotSpotIntrinsicCandidate 1937 public static long reverseBytes(long i) { 1938 i = (i & 0x00ff00ff00ff00ffL) << 8 | (i >>> 8) & 0x00ff00ff00ff00ffL; 1939 return (i << 48) | ((i & 0xffff0000L) << 16) | 1940 ((i >>> 16) & 0xffff0000L) | (i >>> 48); 1941 } 1942 1943 /** 1944 * Adds two {@code long} values together as per the + operator. 1945 * 1946 * @param a the first operand 1947 * @param b the second operand 1948 * @return the sum of {@code a} and {@code b} 1949 * @see java.util.function.BinaryOperator 1950 * @since 1.8 1951 */ 1952 public static long sum(long a, long b) { 1953 return a + b; 1954 } 1955 1956 /** 1957 * Returns the greater of two {@code long} values 1958 * as if by calling {@link Math#max(long, long) Math.max}. 1959 * 1960 * @param a the first operand 1961 * @param b the second operand 1962 * @return the greater of {@code a} and {@code b} 1963 * @see java.util.function.BinaryOperator 1964 * @since 1.8 1965 */ 1966 public static long max(long a, long b) { 1967 return Math.max(a, b); 1968 } 1969 1970 /** 1971 * Returns the smaller of two {@code long} values 1972 * as if by calling {@link Math#min(long, long) Math.min}. 1973 * 1974 * @param a the first operand 1975 * @param b the second operand 1976 * @return the smaller of {@code a} and {@code b} 1977 * @see java.util.function.BinaryOperator 1978 * @since 1.8 1979 */ 1980 public static long min(long a, long b) { 1981 return Math.min(a, b); 1982 } 1983 1984 /** use serialVersionUID from JDK 1.0.2 for interoperability */ 1985 @Native private static final long serialVersionUID = 4290774380558885855L; 1986 }