1 /* 2 * Copyright (c) 1994, 2016, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. Oracle designates this 8 * particular file as subject to the "Classpath" exception as provided 9 * by Oracle in the LICENSE file that accompanied this code. 10 * 11 * This code is distributed in the hope that it will be useful, but WITHOUT 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 * version 2 for more details (a copy is included in the LICENSE file that 15 * accompanied this code). 16 * 17 * You should have received a copy of the GNU General Public License version 18 * 2 along with this work; if not, write to the Free Software Foundation, 19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 20 * 21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have any 23 * questions. 24 */ 25 26 package java.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 if (COMPACT_STRINGS) { 383 byte[] buf = new byte[chars]; 384 formatUnsignedLong0(val, shift, buf, 0, chars); 385 return new String(buf, LATIN1); 386 } else { 387 byte[] buf = new byte[chars * 2]; 388 formatUnsignedLong0UTF16(val, shift, buf, 0, chars); 389 return new String(buf, UTF16); 390 } 391 } 392 393 /** 394 * Format a long (treated as unsigned) into a character buffer. If 395 * {@code len} exceeds the formatted ASCII representation of {@code val}, 396 * {@code buf} will be padded with leading zeroes. 397 * 398 * @param val the unsigned long to format 399 * @param shift the log2 of the base to format in (4 for hex, 3 for octal, 1 for binary) 400 * @param buf the character buffer to write to 401 * @param offset the offset in the destination buffer to start at 402 * @param len the number of characters to write 403 */ 404 405 /** byte[]/LATIN1 version */ 406 static void formatUnsignedLong0(long val, int shift, byte[] buf, int offset, int len) { 407 int charPos = offset + len; 408 int radix = 1 << shift; 409 int mask = radix - 1; 410 do { 411 buf[--charPos] = (byte)Integer.digits[((int) val) & mask]; 412 val >>>= shift; 413 } while (charPos > offset); 414 } 415 416 /** byte[]/UTF16 version */ 417 static void formatUnsignedLong0UTF16(long val, int shift, byte[] buf, int offset, int len) { 418 int charPos = offset + len; 419 int radix = 1 << shift; 420 int mask = radix - 1; 421 do { 422 StringUTF16.putChar(buf, --charPos, Integer.digits[((int) val) & mask]); 423 val >>>= shift; 424 } while (charPos > offset); 425 } 426 427 static String fastUUID(long lsb, long msb) { 428 if (COMPACT_STRINGS) { 429 byte[] buf = new byte[36]; 430 formatUnsignedLong0(lsb, 4, buf, 24, 12); 431 formatUnsignedLong0(lsb >> 48, 4, buf, 19, 4); 432 formatUnsignedLong0(msb, 4, buf, 14, 4); 433 formatUnsignedLong0(msb >> 16, 4, buf, 9, 4); 434 formatUnsignedLong0(msb >> 32, 4, buf, 0, 8); 435 436 buf[23] = '-'; 437 buf[18] = '-'; 438 buf[13] = '-'; 439 buf[8] = '-'; 440 441 return new String(buf, LATIN1); 442 } else { 443 byte[] buf = new byte[72]; 444 445 formatUnsignedLong0UTF16(lsb, 4, buf, 24, 12); 446 formatUnsignedLong0UTF16(lsb >> 48, 4, buf, 19, 4); 447 formatUnsignedLong0UTF16(msb, 4, buf, 14, 4); 448 formatUnsignedLong0UTF16(msb >> 16, 4, buf, 9, 4); 449 formatUnsignedLong0UTF16(msb >> 32, 4, buf, 0, 8); 450 451 StringUTF16.putChar(buf, 23, '-'); 452 StringUTF16.putChar(buf, 18, '-'); 453 StringUTF16.putChar(buf, 13, '-'); 454 StringUTF16.putChar(buf, 8, '-'); 455 456 return new String(buf, UTF16); 457 } 458 } 459 460 /** 461 * Returns a {@code String} object representing the specified 462 * {@code long}. The argument is converted to signed decimal 463 * representation and returned as a string, exactly as if the 464 * argument and the radix 10 were given as arguments to the {@link 465 * #toString(long, int)} method. 466 * 467 * @param i a {@code long} to be converted. 468 * @return a string representation of the argument in base 10. 469 */ 470 public static String toString(long i) { 471 int size = stringSize(i); 472 if (COMPACT_STRINGS) { 473 byte[] buf = new byte[size]; 474 getChars(i, size, buf); 475 return new String(buf, LATIN1); 476 } else { 477 byte[] buf = new byte[size * 2]; 478 getCharsUTF16(i, size, buf); 479 return new String(buf, UTF16); 480 } 481 } 482 483 /** 484 * Returns a string representation of the argument as an unsigned 485 * decimal value. 486 * 487 * The argument is converted to unsigned decimal representation 488 * and returned as a string exactly as if the argument and radix 489 * 10 were given as arguments to the {@link #toUnsignedString(long, 490 * int)} method. 491 * 492 * @param i an integer to be converted to an unsigned string. 493 * @return an unsigned string representation of the argument. 494 * @see #toUnsignedString(long, int) 495 * @since 1.8 496 */ 497 public static String toUnsignedString(long i) { 498 return toUnsignedString(i, 10); 499 } 500 501 /** 502 * Places characters representing the long i into the 503 * character array buf. The characters are placed into 504 * the buffer backwards starting with the least significant 505 * digit at the specified index (exclusive), and working 506 * backwards from there. 507 * 508 * @implNote This method converts positive inputs into negative 509 * values, to cover the Long.MIN_VALUE case. Converting otherwise 510 * (negative to positive) will expose -Long.MIN_VALUE that overflows 511 * long. 512 * 513 * @param i value to convert 514 * @param index next index, after the least significant digit 515 * @param buf target buffer, Latin1-encoded 516 * @return index of the most significant digit or minus sign, if present 517 */ 518 static int getChars(long i, int index, byte[] buf) { 519 long q; 520 int r; 521 int charPos = index; 522 523 boolean negative = (i < 0); 524 if (!negative) { 525 i = -i; 526 } 527 528 // Get 2 digits/iteration using longs until quotient fits into an int 529 while (i <= Integer.MIN_VALUE) { 530 q = i / 100; 531 r = (int)((q * 100) - i); 532 i = q; 533 buf[--charPos] = Integer.DigitOnes[r]; 534 buf[--charPos] = Integer.DigitTens[r]; 535 } 536 537 // Get 2 digits/iteration using ints 538 int q2; 539 int i2 = (int)i; 540 while (i2 <= -100) { 541 q2 = i2 / 100; 542 r = (q2 * 100) - i2; 543 i2 = q2; 544 buf[--charPos] = Integer.DigitOnes[r]; 545 buf[--charPos] = Integer.DigitTens[r]; 546 } 547 548 // We know there are at most two digits left at this point. 549 q2 = i2 / 10; 550 r = (q2 * 10) - i2; 551 buf[--charPos] = (byte)('0' + r); 552 553 // Whatever left is the remaining digit. 554 if (q2 < 0) { 555 buf[--charPos] = (byte)('0' - q2); 556 } 557 558 if (negative) { 559 buf[--charPos] = (byte)'-'; 560 } 561 return charPos; 562 } 563 564 /** 565 * This is a variant of {@link #getChars(long, int, byte[])}, but for 566 * UTF-16 coder. 567 * 568 * @param i value to convert 569 * @param index next index, after the least significant digit 570 * @param buf target buffer, UTF16-coded. 571 * @return index of the most significant digit or minus sign, if present 572 */ 573 static int getCharsUTF16(long i, int index, byte[] buf) { 574 long q; 575 int r; 576 int charPos = index; 577 578 boolean negative = (i < 0); 579 if (!negative) { 580 i = -i; 581 } 582 583 // Get 2 digits/iteration using longs until quotient fits into an int 584 while (i <= Integer.MIN_VALUE) { 585 q = i / 100; 586 r = (int)((q * 100) - i); 587 i = q; 588 StringUTF16.putChar(buf, --charPos, Integer.DigitOnes[r]); 589 StringUTF16.putChar(buf, --charPos, Integer.DigitTens[r]); 590 } 591 592 // Get 2 digits/iteration using ints 593 int q2; 594 int i2 = (int)i; 595 while (i2 <= -100) { 596 q2 = i2 / 100; 597 r = (q2 * 100) - i2; 598 i2 = q2; 599 StringUTF16.putChar(buf, --charPos, Integer.DigitOnes[r]); 600 StringUTF16.putChar(buf, --charPos, Integer.DigitTens[r]); 601 } 602 603 // We know there are at most two digits left at this point. 604 q2 = i2 / 10; 605 r = (q2 * 10) - i2; 606 StringUTF16.putChar(buf, --charPos, '0' + r); 607 608 // Whatever left is the remaining digit. 609 if (q2 < 0) { 610 StringUTF16.putChar(buf, --charPos, '0' - q2); 611 } 612 613 if (negative) { 614 StringUTF16.putChar(buf, --charPos, '-'); 615 } 616 return charPos; 617 } 618 619 /** 620 * Returns the string representation size for a given long value. 621 * 622 * @param x long value 623 * @return string size 624 * 625 * @implNote There are other ways to compute this: e.g. binary search, 626 * but values are biased heavily towards zero, and therefore linear search 627 * wins. The iteration results are also routinely inlined in the generated 628 * code after loop unrolling. 629 */ 630 static int stringSize(long x) { 631 int d = 1; 632 if (x >= 0) { 633 d = 0; 634 x = -x; 635 } 636 long p = -10; 637 for (int i = 1; i < 19; i++) { 638 if (x > p) 639 return i + d; 640 p = 10 * p; 641 } 642 return 19 + d; 643 } 644 645 /** 646 * Parses the string argument as a signed {@code long} in the 647 * radix specified by the second argument. The characters in the 648 * string must all be digits of the specified radix (as determined 649 * by whether {@link java.lang.Character#digit(char, int)} returns 650 * a nonnegative value), except that the first character may be an 651 * ASCII minus sign {@code '-'} ({@code '\u005Cu002D'}) to 652 * indicate a negative value or an ASCII plus sign {@code '+'} 653 * ({@code '\u005Cu002B'}) to indicate a positive value. The 654 * resulting {@code long} value is returned. 655 * 656 * <p>Note that neither the character {@code L} 657 * ({@code '\u005Cu004C'}) nor {@code l} 658 * ({@code '\u005Cu006C'}) is permitted to appear at the end 659 * of the string as a type indicator, as would be permitted in 660 * Java programming language source code - except that either 661 * {@code L} or {@code l} may appear as a digit for a 662 * radix greater than or equal to 22. 663 * 664 * <p>An exception of type {@code NumberFormatException} is 665 * thrown if any of the following situations occurs: 666 * <ul> 667 * 668 * <li>The first argument is {@code null} or is a string of 669 * length zero. 670 * 671 * <li>The {@code radix} is either smaller than {@link 672 * java.lang.Character#MIN_RADIX} or larger than {@link 673 * java.lang.Character#MAX_RADIX}. 674 * 675 * <li>Any character of the string is not a digit of the specified 676 * radix, except that the first character may be a minus sign 677 * {@code '-'} ({@code '\u005Cu002d'}) or plus sign {@code 678 * '+'} ({@code '\u005Cu002B'}) provided that the string is 679 * longer than length 1. 680 * 681 * <li>The value represented by the string is not a value of type 682 * {@code long}. 683 * </ul> 684 * 685 * <p>Examples: 686 * <blockquote><pre> 687 * parseLong("0", 10) returns 0L 688 * parseLong("473", 10) returns 473L 689 * parseLong("+42", 10) returns 42L 690 * parseLong("-0", 10) returns 0L 691 * parseLong("-FF", 16) returns -255L 692 * parseLong("1100110", 2) returns 102L 693 * parseLong("99", 8) throws a NumberFormatException 694 * parseLong("Hazelnut", 10) throws a NumberFormatException 695 * parseLong("Hazelnut", 36) returns 1356099454469L 696 * </pre></blockquote> 697 * 698 * @param s the {@code String} containing the 699 * {@code long} representation to be parsed. 700 * @param radix the radix to be used while parsing {@code s}. 701 * @return the {@code long} represented by the string argument in 702 * the specified radix. 703 * @throws NumberFormatException if the string does not contain a 704 * parsable {@code long}. 705 */ 706 public static long parseLong(String s, int radix) 707 throws NumberFormatException 708 { 709 if (s == null) { 710 throw new NumberFormatException("null"); 711 } 712 713 if (radix < Character.MIN_RADIX) { 714 throw new NumberFormatException("radix " + radix + 715 " less than Character.MIN_RADIX"); 716 } 717 if (radix > Character.MAX_RADIX) { 718 throw new NumberFormatException("radix " + radix + 719 " greater than Character.MAX_RADIX"); 720 } 721 722 boolean negative = false; 723 int i = 0, len = s.length(); 724 long limit = -Long.MAX_VALUE; 725 726 if (len > 0) { 727 char firstChar = s.charAt(0); 728 if (firstChar < '0') { // Possible leading "+" or "-" 729 if (firstChar == '-') { 730 negative = true; 731 limit = Long.MIN_VALUE; 732 } else if (firstChar != '+') { 733 throw NumberFormatException.forInputString(s); 734 } 735 736 if (len == 1) { // Cannot have lone "+" or "-" 737 throw NumberFormatException.forInputString(s); 738 } 739 i++; 740 } 741 long multmin = limit / radix; 742 long result = 0; 743 while (i < len) { 744 // Accumulating negatively avoids surprises near MAX_VALUE 745 int digit = Character.digit(s.charAt(i++),radix); 746 if (digit < 0 || result < multmin) { 747 throw NumberFormatException.forInputString(s); 748 } 749 result *= radix; 750 if (result < limit + digit) { 751 throw NumberFormatException.forInputString(s); 752 } 753 result -= digit; 754 } 755 return negative ? result : -result; 756 } else { 757 throw NumberFormatException.forInputString(s); 758 } 759 } 760 761 /** 762 * Parses the {@link CharSequence} argument as a signed {@code long} in 763 * the specified {@code radix}, beginning at the specified 764 * {@code beginIndex} and extending to {@code endIndex - 1}. 765 * 766 * <p>The method does not take steps to guard against the 767 * {@code CharSequence} being mutated while parsing. 768 * 769 * @param s the {@code CharSequence} containing the {@code long} 770 * representation to be parsed 771 * @param beginIndex the beginning index, inclusive. 772 * @param endIndex the ending index, exclusive. 773 * @param radix the radix to be used while parsing {@code s}. 774 * @return the signed {@code long} represented by the subsequence in 775 * the specified radix. 776 * @throws NullPointerException if {@code s} is null. 777 * @throws IndexOutOfBoundsException if {@code beginIndex} is 778 * negative, or if {@code beginIndex} is greater than 779 * {@code endIndex} or if {@code endIndex} is greater than 780 * {@code s.length()}. 781 * @throws NumberFormatException if the {@code CharSequence} does not 782 * contain a parsable {@code int} in the specified 783 * {@code radix}, or if {@code radix} is either smaller than 784 * {@link java.lang.Character#MIN_RADIX} or larger than 785 * {@link java.lang.Character#MAX_RADIX}. 786 * @since 9 787 */ 788 public static long parseLong(CharSequence s, int beginIndex, int endIndex, int radix) 789 throws NumberFormatException { 790 s = Objects.requireNonNull(s); 791 792 if (beginIndex < 0 || beginIndex > endIndex || endIndex > s.length()) { 793 throw new IndexOutOfBoundsException(); 794 } 795 if (radix < Character.MIN_RADIX) { 796 throw new NumberFormatException("radix " + radix + 797 " less than Character.MIN_RADIX"); 798 } 799 if (radix > Character.MAX_RADIX) { 800 throw new NumberFormatException("radix " + radix + 801 " greater than Character.MAX_RADIX"); 802 } 803 804 boolean negative = false; 805 int i = beginIndex; 806 long limit = -Long.MAX_VALUE; 807 808 if (i < endIndex) { 809 char firstChar = s.charAt(i); 810 if (firstChar < '0') { // Possible leading "+" or "-" 811 if (firstChar == '-') { 812 negative = true; 813 limit = Long.MIN_VALUE; 814 } else if (firstChar != '+') { 815 throw NumberFormatException.forCharSequence(s, beginIndex, 816 endIndex, i); 817 } 818 i++; 819 } 820 if (i >= endIndex) { // Cannot have lone "+", "-" or "" 821 throw NumberFormatException.forCharSequence(s, beginIndex, 822 endIndex, i); 823 } 824 long multmin = limit / radix; 825 long result = 0; 826 while (i < endIndex) { 827 // Accumulating negatively avoids surprises near MAX_VALUE 828 int digit = Character.digit(s.charAt(i), radix); 829 if (digit < 0 || result < multmin) { 830 throw NumberFormatException.forCharSequence(s, beginIndex, 831 endIndex, i); 832 } 833 result *= radix; 834 if (result < limit + digit) { 835 throw NumberFormatException.forCharSequence(s, beginIndex, 836 endIndex, i); 837 } 838 i++; 839 result -= digit; 840 } 841 return negative ? result : -result; 842 } else { 843 throw new NumberFormatException(""); 844 } 845 } 846 847 /** 848 * Parses the string argument as a signed decimal {@code long}. 849 * The characters in the string must all be decimal digits, except 850 * that the first character may be an ASCII minus sign {@code '-'} 851 * ({@code \u005Cu002D'}) to indicate a negative value or an 852 * ASCII plus sign {@code '+'} ({@code '\u005Cu002B'}) to 853 * indicate a positive value. The resulting {@code long} value is 854 * returned, exactly as if the argument and the radix {@code 10} 855 * were given as arguments to the {@link 856 * #parseLong(java.lang.String, int)} method. 857 * 858 * <p>Note that neither the character {@code L} 859 * ({@code '\u005Cu004C'}) nor {@code l} 860 * ({@code '\u005Cu006C'}) is permitted to appear at the end 861 * of the string as a type indicator, as would be permitted in 862 * Java programming language source code. 863 * 864 * @param s a {@code String} containing the {@code long} 865 * representation to be parsed 866 * @return the {@code long} represented by the argument in 867 * decimal. 868 * @throws NumberFormatException if the string does not contain a 869 * parsable {@code long}. 870 */ 871 public static long parseLong(String s) throws NumberFormatException { 872 return parseLong(s, 10); 873 } 874 875 /** 876 * Parses the string argument as an unsigned {@code long} in the 877 * radix specified by the second argument. An unsigned integer 878 * maps the values usually associated with negative numbers to 879 * positive numbers larger than {@code MAX_VALUE}. 880 * 881 * The characters in the string must all be digits of the 882 * specified radix (as determined by whether {@link 883 * java.lang.Character#digit(char, int)} returns a nonnegative 884 * value), except that the first character may be an ASCII plus 885 * sign {@code '+'} ({@code '\u005Cu002B'}). The resulting 886 * integer value is returned. 887 * 888 * <p>An exception of type {@code NumberFormatException} is 889 * thrown if any of the following situations occurs: 890 * <ul> 891 * <li>The first argument is {@code null} or is a string of 892 * length zero. 893 * 894 * <li>The radix is either smaller than 895 * {@link java.lang.Character#MIN_RADIX} or 896 * larger than {@link java.lang.Character#MAX_RADIX}. 897 * 898 * <li>Any character of the string is not a digit of the specified 899 * radix, except that the first character may be a plus sign 900 * {@code '+'} ({@code '\u005Cu002B'}) provided that the 901 * string is longer than length 1. 902 * 903 * <li>The value represented by the string is larger than the 904 * largest unsigned {@code long}, 2<sup>64</sup>-1. 905 * 906 * </ul> 907 * 908 * 909 * @param s the {@code String} containing the unsigned integer 910 * representation to be parsed 911 * @param radix the radix to be used while parsing {@code s}. 912 * @return the unsigned {@code long} represented by the string 913 * argument in the specified radix. 914 * @throws NumberFormatException if the {@code String} 915 * does not contain a parsable {@code long}. 916 * @since 1.8 917 */ 918 public static long parseUnsignedLong(String s, int radix) 919 throws NumberFormatException { 920 if (s == null) { 921 throw new NumberFormatException("null"); 922 } 923 924 int len = s.length(); 925 if (len > 0) { 926 char firstChar = s.charAt(0); 927 if (firstChar == '-') { 928 throw new 929 NumberFormatException(String.format("Illegal leading minus sign " + 930 "on unsigned string %s.", s)); 931 } else { 932 if (len <= 12 || // Long.MAX_VALUE in Character.MAX_RADIX is 13 digits 933 (radix == 10 && len <= 18) ) { // Long.MAX_VALUE in base 10 is 19 digits 934 return parseLong(s, radix); 935 } 936 937 // No need for range checks on len due to testing above. 938 long first = parseLong(s, 0, len - 1, radix); 939 int second = Character.digit(s.charAt(len - 1), radix); 940 if (second < 0) { 941 throw new NumberFormatException("Bad digit at end of " + s); 942 } 943 long result = first * radix + second; 944 945 /* 946 * Test leftmost bits of multiprecision extension of first*radix 947 * for overflow. The number of bits needed is defined by 948 * GUARD_BIT = ceil(log2(Character.MAX_RADIX)) + 1 = 7. Then 949 * int guard = radix*(int)(first >>> (64 - GUARD_BIT)) and 950 * overflow is tested by splitting guard in the ranges 951 * guard < 92, 92 <= guard < 128, and 128 <= guard, where 952 * 92 = 128 - Character.MAX_RADIX. Note that guard cannot take 953 * on a value which does not include a prime factor in the legal 954 * radix range. 955 */ 956 int guard = radix * (int) (first >>> 57); 957 if (guard >= 128 || 958 (result >= 0 && guard >= 128 - Character.MAX_RADIX)) { 959 /* 960 * For purposes of exposition, the programmatic statements 961 * below should be taken to be multi-precision, i.e., not 962 * subject to overflow. 963 * 964 * A) Condition guard >= 128: 965 * If guard >= 128 then first*radix >= 2^7 * 2^57 = 2^64 966 * hence always overflow. 967 * 968 * B) Condition guard < 92: 969 * Define left7 = first >>> 57. 970 * Given first = (left7 * 2^57) + (first & (2^57 - 1)) then 971 * result <= (radix*left7)*2^57 + radix*(2^57 - 1) + second. 972 * Thus if radix*left7 < 92, radix <= 36, and second < 36, 973 * then result < 92*2^57 + 36*(2^57 - 1) + 36 = 2^64 hence 974 * never overflow. 975 * 976 * C) Condition 92 <= guard < 128: 977 * first*radix + second >= radix*left7*2^57 + second 978 * so that first*radix + second >= 92*2^57 + 0 > 2^63 979 * 980 * D) Condition guard < 128: 981 * radix*first <= (radix*left7) * 2^57 + radix*(2^57 - 1) 982 * so 983 * radix*first + second <= (radix*left7) * 2^57 + radix*(2^57 - 1) + 36 984 * thus 985 * radix*first + second < 128 * 2^57 + 36*2^57 - radix + 36 986 * whence 987 * radix*first + second < 2^64 + 2^6*2^57 = 2^64 + 2^63 988 * 989 * E) Conditions C, D, and result >= 0: 990 * C and D combined imply the mathematical result 991 * 2^63 < first*radix + second < 2^64 + 2^63. The lower 992 * bound is therefore negative as a signed long, but the 993 * upper bound is too small to overflow again after the 994 * signed long overflows to positive above 2^64 - 1. Hence 995 * result >= 0 implies overflow given C and D. 996 */ 997 throw new NumberFormatException(String.format("String value %s exceeds " + 998 "range of unsigned long.", s)); 999 } 1000 return result; 1001 } 1002 } else { 1003 throw NumberFormatException.forInputString(s); 1004 } 1005 } 1006 1007 /** 1008 * Parses the {@link CharSequence} argument as an unsigned {@code long} in 1009 * the specified {@code radix}, beginning at the specified 1010 * {@code beginIndex} and extending to {@code endIndex - 1}. 1011 * 1012 * <p>The method does not take steps to guard against the 1013 * {@code CharSequence} being mutated while parsing. 1014 * 1015 * @param s the {@code CharSequence} containing the unsigned 1016 * {@code long} representation to be parsed 1017 * @param beginIndex the beginning index, inclusive. 1018 * @param endIndex the ending index, exclusive. 1019 * @param radix the radix to be used while parsing {@code s}. 1020 * @return the unsigned {@code long} represented by the subsequence in 1021 * the specified radix. 1022 * @throws NullPointerException if {@code s} is null. 1023 * @throws IndexOutOfBoundsException if {@code beginIndex} is 1024 * negative, or if {@code beginIndex} is greater than 1025 * {@code endIndex} or if {@code endIndex} is greater than 1026 * {@code s.length()}. 1027 * @throws NumberFormatException if the {@code CharSequence} does not 1028 * contain a parsable unsigned {@code long} in the specified 1029 * {@code radix}, or if {@code radix} is either smaller than 1030 * {@link java.lang.Character#MIN_RADIX} or larger than 1031 * {@link java.lang.Character#MAX_RADIX}. 1032 * @since 9 1033 */ 1034 public static long parseUnsignedLong(CharSequence s, int beginIndex, int endIndex, int radix) 1035 throws NumberFormatException { 1036 s = Objects.requireNonNull(s); 1037 1038 if (beginIndex < 0 || beginIndex > endIndex || endIndex > s.length()) { 1039 throw new IndexOutOfBoundsException(); 1040 } 1041 int start = beginIndex, len = endIndex - beginIndex; 1042 1043 if (len > 0) { 1044 char firstChar = s.charAt(start); 1045 if (firstChar == '-') { 1046 throw new NumberFormatException(String.format("Illegal leading minus sign " + 1047 "on unsigned string %s.", s.subSequence(start, start + len))); 1048 } else { 1049 if (len <= 12 || // Long.MAX_VALUE in Character.MAX_RADIX is 13 digits 1050 (radix == 10 && len <= 18) ) { // Long.MAX_VALUE in base 10 is 19 digits 1051 return parseLong(s, start, start + len, radix); 1052 } 1053 1054 // No need for range checks on end due to testing above. 1055 long first = parseLong(s, start, start + len - 1, radix); 1056 int second = Character.digit(s.charAt(start + len - 1), radix); 1057 if (second < 0) { 1058 throw new NumberFormatException("Bad digit at end of " + 1059 s.subSequence(start, start + len)); 1060 } 1061 long result = first * radix + second; 1062 1063 /* 1064 * Test leftmost bits of multiprecision extension of first*radix 1065 * for overflow. The number of bits needed is defined by 1066 * GUARD_BIT = ceil(log2(Character.MAX_RADIX)) + 1 = 7. Then 1067 * int guard = radix*(int)(first >>> (64 - GUARD_BIT)) and 1068 * overflow is tested by splitting guard in the ranges 1069 * guard < 92, 92 <= guard < 128, and 128 <= guard, where 1070 * 92 = 128 - Character.MAX_RADIX. Note that guard cannot take 1071 * on a value which does not include a prime factor in the legal 1072 * radix range. 1073 */ 1074 int guard = radix * (int) (first >>> 57); 1075 if (guard >= 128 || 1076 (result >= 0 && guard >= 128 - Character.MAX_RADIX)) { 1077 /* 1078 * For purposes of exposition, the programmatic statements 1079 * below should be taken to be multi-precision, i.e., not 1080 * subject to overflow. 1081 * 1082 * A) Condition guard >= 128: 1083 * If guard >= 128 then first*radix >= 2^7 * 2^57 = 2^64 1084 * hence always overflow. 1085 * 1086 * B) Condition guard < 92: 1087 * Define left7 = first >>> 57. 1088 * Given first = (left7 * 2^57) + (first & (2^57 - 1)) then 1089 * result <= (radix*left7)*2^57 + radix*(2^57 - 1) + second. 1090 * Thus if radix*left7 < 92, radix <= 36, and second < 36, 1091 * then result < 92*2^57 + 36*(2^57 - 1) + 36 = 2^64 hence 1092 * never overflow. 1093 * 1094 * C) Condition 92 <= guard < 128: 1095 * first*radix + second >= radix*left7*2^57 + second 1096 * so that first*radix + second >= 92*2^57 + 0 > 2^63 1097 * 1098 * D) Condition guard < 128: 1099 * radix*first <= (radix*left7) * 2^57 + radix*(2^57 - 1) 1100 * so 1101 * radix*first + second <= (radix*left7) * 2^57 + radix*(2^57 - 1) + 36 1102 * thus 1103 * radix*first + second < 128 * 2^57 + 36*2^57 - radix + 36 1104 * whence 1105 * radix*first + second < 2^64 + 2^6*2^57 = 2^64 + 2^63 1106 * 1107 * E) Conditions C, D, and result >= 0: 1108 * C and D combined imply the mathematical result 1109 * 2^63 < first*radix + second < 2^64 + 2^63. The lower 1110 * bound is therefore negative as a signed long, but the 1111 * upper bound is too small to overflow again after the 1112 * signed long overflows to positive above 2^64 - 1. Hence 1113 * result >= 0 implies overflow given C and D. 1114 */ 1115 throw new NumberFormatException(String.format("String value %s exceeds " + 1116 "range of unsigned long.", s.subSequence(start, start + len))); 1117 } 1118 return result; 1119 } 1120 } else { 1121 throw NumberFormatException.forInputString(""); 1122 } 1123 } 1124 1125 /** 1126 * Parses the string argument as an unsigned decimal {@code long}. The 1127 * characters in the string must all be decimal digits, except 1128 * that the first character may be an ASCII plus sign {@code 1129 * '+'} ({@code '\u005Cu002B'}). The resulting integer value 1130 * is returned, exactly as if the argument and the radix 10 were 1131 * given as arguments to the {@link 1132 * #parseUnsignedLong(java.lang.String, int)} method. 1133 * 1134 * @param s a {@code String} containing the unsigned {@code long} 1135 * representation to be parsed 1136 * @return the unsigned {@code long} value represented by the decimal string argument 1137 * @throws NumberFormatException if the string does not contain a 1138 * parsable unsigned integer. 1139 * @since 1.8 1140 */ 1141 public static long parseUnsignedLong(String s) throws NumberFormatException { 1142 return parseUnsignedLong(s, 10); 1143 } 1144 1145 /** 1146 * Returns a {@code Long} object holding the value 1147 * extracted from the specified {@code String} when parsed 1148 * with the radix given by the second argument. The first 1149 * argument is interpreted as representing a signed 1150 * {@code long} in the radix specified by the second 1151 * argument, exactly as if the arguments were given to the {@link 1152 * #parseLong(java.lang.String, int)} method. The result is a 1153 * {@code Long} object that represents the {@code long} 1154 * value specified by the string. 1155 * 1156 * <p>In other words, this method returns a {@code Long} object equal 1157 * to the value of: 1158 * 1159 * <blockquote> 1160 * {@code new Long(Long.parseLong(s, radix))} 1161 * </blockquote> 1162 * 1163 * @param s the string to be parsed 1164 * @param radix the radix to be used in interpreting {@code s} 1165 * @return a {@code Long} object holding the value 1166 * represented by the string argument in the specified 1167 * radix. 1168 * @throws NumberFormatException If the {@code String} does not 1169 * contain a parsable {@code long}. 1170 */ 1171 public static Long valueOf(String s, int radix) throws NumberFormatException { 1172 return Long.valueOf(parseLong(s, radix)); 1173 } 1174 1175 /** 1176 * Returns a {@code Long} object holding the value 1177 * of the specified {@code String}. The argument is 1178 * interpreted as representing a signed decimal {@code long}, 1179 * exactly as if the argument were given to the {@link 1180 * #parseLong(java.lang.String)} method. The result is a 1181 * {@code Long} object that represents the integer value 1182 * specified by the string. 1183 * 1184 * <p>In other words, this method returns a {@code Long} object 1185 * equal to the value of: 1186 * 1187 * <blockquote> 1188 * {@code new Long(Long.parseLong(s))} 1189 * </blockquote> 1190 * 1191 * @param s the string to be parsed. 1192 * @return a {@code Long} object holding the value 1193 * represented by the string argument. 1194 * @throws NumberFormatException If the string cannot be parsed 1195 * as a {@code long}. 1196 */ 1197 public static Long valueOf(String s) throws NumberFormatException 1198 { 1199 return Long.valueOf(parseLong(s, 10)); 1200 } 1201 1202 private static class LongCache { 1203 private LongCache(){} 1204 1205 static final Long cache[] = new Long[-(-128) + 127 + 1]; 1206 1207 static { 1208 for(int i = 0; i < cache.length; i++) 1209 cache[i] = new Long(i - 128); 1210 } 1211 } 1212 1213 /** 1214 * Returns a {@code Long} instance representing the specified 1215 * {@code long} value. 1216 * If a new {@code Long} instance is not required, this method 1217 * should generally be used in preference to the constructor 1218 * {@link #Long(long)}, as this method is likely to yield 1219 * significantly better space and time performance by caching 1220 * frequently requested values. 1221 * 1222 * Note that unlike the {@linkplain Integer#valueOf(int) 1223 * corresponding method} in the {@code Integer} class, this method 1224 * is <em>not</em> required to cache values within a particular 1225 * range. 1226 * 1227 * @param l a long value. 1228 * @return a {@code Long} instance representing {@code l}. 1229 * @since 1.5 1230 */ 1231 @HotSpotIntrinsicCandidate 1232 public static Long valueOf(long l) { 1233 final int offset = 128; 1234 if (l >= -128 && l <= 127) { // will cache 1235 return LongCache.cache[(int)l + offset]; 1236 } 1237 return new Long(l); 1238 } 1239 1240 /** 1241 * Decodes a {@code String} into a {@code Long}. 1242 * Accepts decimal, hexadecimal, and octal numbers given by the 1243 * following grammar: 1244 * 1245 * <blockquote> 1246 * <dl> 1247 * <dt><i>DecodableString:</i> 1248 * <dd><i>Sign<sub>opt</sub> DecimalNumeral</i> 1249 * <dd><i>Sign<sub>opt</sub></i> {@code 0x} <i>HexDigits</i> 1250 * <dd><i>Sign<sub>opt</sub></i> {@code 0X} <i>HexDigits</i> 1251 * <dd><i>Sign<sub>opt</sub></i> {@code #} <i>HexDigits</i> 1252 * <dd><i>Sign<sub>opt</sub></i> {@code 0} <i>OctalDigits</i> 1253 * 1254 * <dt><i>Sign:</i> 1255 * <dd>{@code -} 1256 * <dd>{@code +} 1257 * </dl> 1258 * </blockquote> 1259 * 1260 * <i>DecimalNumeral</i>, <i>HexDigits</i>, and <i>OctalDigits</i> 1261 * are as defined in section 3.10.1 of 1262 * <cite>The Java™ Language Specification</cite>, 1263 * except that underscores are not accepted between digits. 1264 * 1265 * <p>The sequence of characters following an optional 1266 * sign and/or radix specifier ("{@code 0x}", "{@code 0X}", 1267 * "{@code #}", or leading zero) is parsed as by the {@code 1268 * Long.parseLong} method with the indicated radix (10, 16, or 8). 1269 * This sequence of characters must represent a positive value or 1270 * a {@link NumberFormatException} will be thrown. The result is 1271 * negated if first character of the specified {@code String} is 1272 * the minus sign. No whitespace characters are permitted in the 1273 * {@code String}. 1274 * 1275 * @param nm the {@code String} to decode. 1276 * @return a {@code Long} object holding the {@code long} 1277 * value represented by {@code nm} 1278 * @throws NumberFormatException if the {@code String} does not 1279 * contain a parsable {@code long}. 1280 * @see java.lang.Long#parseLong(String, int) 1281 * @since 1.2 1282 */ 1283 public static Long decode(String nm) throws NumberFormatException { 1284 int radix = 10; 1285 int index = 0; 1286 boolean negative = false; 1287 Long result; 1288 1289 if (nm.length() == 0) 1290 throw new NumberFormatException("Zero length string"); 1291 char firstChar = nm.charAt(0); 1292 // Handle sign, if present 1293 if (firstChar == '-') { 1294 negative = true; 1295 index++; 1296 } else if (firstChar == '+') 1297 index++; 1298 1299 // Handle radix specifier, if present 1300 if (nm.startsWith("0x", index) || nm.startsWith("0X", index)) { 1301 index += 2; 1302 radix = 16; 1303 } 1304 else if (nm.startsWith("#", index)) { 1305 index ++; 1306 radix = 16; 1307 } 1308 else if (nm.startsWith("0", index) && nm.length() > 1 + index) { 1309 index ++; 1310 radix = 8; 1311 } 1312 1313 if (nm.startsWith("-", index) || nm.startsWith("+", index)) 1314 throw new NumberFormatException("Sign character in wrong position"); 1315 1316 try { 1317 result = Long.valueOf(nm.substring(index), radix); 1318 result = negative ? Long.valueOf(-result.longValue()) : result; 1319 } catch (NumberFormatException e) { 1320 // If number is Long.MIN_VALUE, we'll end up here. The next line 1321 // handles this case, and causes any genuine format error to be 1322 // rethrown. 1323 String constant = negative ? ("-" + nm.substring(index)) 1324 : nm.substring(index); 1325 result = Long.valueOf(constant, radix); 1326 } 1327 return result; 1328 } 1329 1330 /** 1331 * The value of the {@code Long}. 1332 * 1333 * @serial 1334 */ 1335 private final long value; 1336 1337 /** 1338 * Constructs a newly allocated {@code Long} object that 1339 * represents the specified {@code long} argument. 1340 * 1341 * @param value the value to be represented by the 1342 * {@code Long} object. 1343 */ 1344 public Long(long value) { 1345 this.value = value; 1346 } 1347 1348 /** 1349 * Constructs a newly allocated {@code Long} object that 1350 * represents the {@code long} value indicated by the 1351 * {@code String} parameter. The string is converted to a 1352 * {@code long} value in exactly the manner used by the 1353 * {@code parseLong} method for radix 10. 1354 * 1355 * @param s the {@code String} to be converted to a 1356 * {@code Long}. 1357 * @throws NumberFormatException if the {@code String} does not 1358 * contain a parsable {@code long}. 1359 * @see java.lang.Long#parseLong(java.lang.String, int) 1360 */ 1361 public Long(String s) throws NumberFormatException { 1362 this.value = parseLong(s, 10); 1363 } 1364 1365 /** 1366 * Returns the value of this {@code Long} as a {@code byte} after 1367 * a narrowing primitive conversion. 1368 * @jls 5.1.3 Narrowing Primitive Conversions 1369 */ 1370 public byte byteValue() { 1371 return (byte)value; 1372 } 1373 1374 /** 1375 * Returns the value of this {@code Long} as a {@code short} after 1376 * a narrowing primitive conversion. 1377 * @jls 5.1.3 Narrowing Primitive Conversions 1378 */ 1379 public short shortValue() { 1380 return (short)value; 1381 } 1382 1383 /** 1384 * Returns the value of this {@code Long} as an {@code int} after 1385 * a narrowing primitive conversion. 1386 * @jls 5.1.3 Narrowing Primitive Conversions 1387 */ 1388 public int intValue() { 1389 return (int)value; 1390 } 1391 1392 /** 1393 * Returns the value of this {@code Long} as a 1394 * {@code long} value. 1395 */ 1396 @HotSpotIntrinsicCandidate 1397 public long longValue() { 1398 return value; 1399 } 1400 1401 /** 1402 * Returns the value of this {@code Long} as a {@code float} after 1403 * a widening primitive conversion. 1404 * @jls 5.1.2 Widening Primitive Conversions 1405 */ 1406 public float floatValue() { 1407 return (float)value; 1408 } 1409 1410 /** 1411 * Returns the value of this {@code Long} as a {@code double} 1412 * after a widening primitive conversion. 1413 * @jls 5.1.2 Widening Primitive Conversions 1414 */ 1415 public double doubleValue() { 1416 return (double)value; 1417 } 1418 1419 /** 1420 * Returns a {@code String} object representing this 1421 * {@code Long}'s value. The value is converted to signed 1422 * decimal representation and returned as a string, exactly as if 1423 * the {@code long} value were given as an argument to the 1424 * {@link java.lang.Long#toString(long)} method. 1425 * 1426 * @return a string representation of the value of this object in 1427 * base 10. 1428 */ 1429 public String toString() { 1430 return toString(value); 1431 } 1432 1433 /** 1434 * Returns a hash code for this {@code Long}. The result is 1435 * the exclusive OR of the two halves of the primitive 1436 * {@code long} value held by this {@code Long} 1437 * object. That is, the hashcode is the value of the expression: 1438 * 1439 * <blockquote> 1440 * {@code (int)(this.longValue()^(this.longValue()>>>32))} 1441 * </blockquote> 1442 * 1443 * @return a hash code value for this object. 1444 */ 1445 @Override 1446 public int hashCode() { 1447 return Long.hashCode(value); 1448 } 1449 1450 /** 1451 * Returns a hash code for a {@code long} value; compatible with 1452 * {@code Long.hashCode()}. 1453 * 1454 * @param value the value to hash 1455 * @return a hash code value for a {@code long} value. 1456 * @since 1.8 1457 */ 1458 public static int hashCode(long value) { 1459 return (int)(value ^ (value >>> 32)); 1460 } 1461 1462 /** 1463 * Compares this object to the specified object. The result is 1464 * {@code true} if and only if the argument is not 1465 * {@code null} and is a {@code Long} object that 1466 * contains the same {@code long} value as this object. 1467 * 1468 * @param obj the object to compare with. 1469 * @return {@code true} if the objects are the same; 1470 * {@code false} otherwise. 1471 */ 1472 public boolean equals(Object obj) { 1473 if (obj instanceof Long) { 1474 return value == ((Long)obj).longValue(); 1475 } 1476 return false; 1477 } 1478 1479 /** 1480 * Determines the {@code long} value of the system property 1481 * with the specified name. 1482 * 1483 * <p>The first argument is treated as the name of a system 1484 * property. System properties are accessible through the {@link 1485 * java.lang.System#getProperty(java.lang.String)} method. The 1486 * string value of this property is then interpreted as a {@code 1487 * long} value using the grammar supported by {@link Long#decode decode} 1488 * and a {@code Long} object representing this value is returned. 1489 * 1490 * <p>If there is no property with the specified name, if the 1491 * specified name is empty or {@code null}, or if the property 1492 * does not have the correct numeric format, then {@code null} is 1493 * returned. 1494 * 1495 * <p>In other words, this method returns a {@code Long} object 1496 * equal to the value of: 1497 * 1498 * <blockquote> 1499 * {@code getLong(nm, null)} 1500 * </blockquote> 1501 * 1502 * @param nm property name. 1503 * @return the {@code Long} value of the property. 1504 * @throws SecurityException for the same reasons as 1505 * {@link System#getProperty(String) System.getProperty} 1506 * @see java.lang.System#getProperty(java.lang.String) 1507 * @see java.lang.System#getProperty(java.lang.String, java.lang.String) 1508 */ 1509 public static Long getLong(String nm) { 1510 return getLong(nm, null); 1511 } 1512 1513 /** 1514 * Determines the {@code long} value of the system property 1515 * with the specified name. 1516 * 1517 * <p>The first argument is treated as the name of a system 1518 * property. System properties are accessible through the {@link 1519 * java.lang.System#getProperty(java.lang.String)} method. The 1520 * string value of this property is then interpreted as a {@code 1521 * long} value using the grammar supported by {@link Long#decode decode} 1522 * and a {@code Long} object representing this value is returned. 1523 * 1524 * <p>The second argument is the default value. A {@code Long} object 1525 * that represents the value of the second argument is returned if there 1526 * is no property of the specified name, if the property does not have 1527 * the correct numeric format, or if the specified name is empty or null. 1528 * 1529 * <p>In other words, this method returns a {@code Long} object equal 1530 * to the value of: 1531 * 1532 * <blockquote> 1533 * {@code getLong(nm, new Long(val))} 1534 * </blockquote> 1535 * 1536 * but in practice it may be implemented in a manner such as: 1537 * 1538 * <blockquote><pre> 1539 * Long result = getLong(nm, null); 1540 * return (result == null) ? new Long(val) : result; 1541 * </pre></blockquote> 1542 * 1543 * to avoid the unnecessary allocation of a {@code Long} object when 1544 * the default value is not needed. 1545 * 1546 * @param nm property name. 1547 * @param val default value. 1548 * @return the {@code Long} value of the property. 1549 * @throws SecurityException for the same reasons as 1550 * {@link System#getProperty(String) System.getProperty} 1551 * @see java.lang.System#getProperty(java.lang.String) 1552 * @see java.lang.System#getProperty(java.lang.String, java.lang.String) 1553 */ 1554 public static Long getLong(String nm, long val) { 1555 Long result = Long.getLong(nm, null); 1556 return (result == null) ? Long.valueOf(val) : result; 1557 } 1558 1559 /** 1560 * Returns the {@code long} value of the system property with 1561 * the specified name. The first argument is treated as the name 1562 * of a system property. System properties are accessible through 1563 * the {@link java.lang.System#getProperty(java.lang.String)} 1564 * method. The string value of this property is then interpreted 1565 * as a {@code long} value, as per the 1566 * {@link Long#decode decode} method, and a {@code Long} object 1567 * representing this value is returned; in summary: 1568 * 1569 * <ul> 1570 * <li>If the property value begins with the two ASCII characters 1571 * {@code 0x} or the ASCII character {@code #}, not followed by 1572 * a minus sign, then the rest of it is parsed as a hexadecimal integer 1573 * exactly as for the method {@link #valueOf(java.lang.String, int)} 1574 * with radix 16. 1575 * <li>If the property value begins with the ASCII character 1576 * {@code 0} followed by another character, it is parsed as 1577 * an octal integer exactly as by the method {@link 1578 * #valueOf(java.lang.String, int)} with radix 8. 1579 * <li>Otherwise the property value is parsed as a decimal 1580 * integer exactly as by the method 1581 * {@link #valueOf(java.lang.String, int)} with radix 10. 1582 * </ul> 1583 * 1584 * <p>Note that, in every case, neither {@code L} 1585 * ({@code '\u005Cu004C'}) nor {@code l} 1586 * ({@code '\u005Cu006C'}) is permitted to appear at the end 1587 * of the property value as a type indicator, as would be 1588 * permitted in Java programming language source code. 1589 * 1590 * <p>The second argument is the default value. The default value is 1591 * returned if there is no property of the specified name, if the 1592 * property does not have the correct numeric format, or if the 1593 * specified name is empty or {@code null}. 1594 * 1595 * @param nm property name. 1596 * @param val default value. 1597 * @return the {@code Long} value of the property. 1598 * @throws SecurityException for the same reasons as 1599 * {@link System#getProperty(String) System.getProperty} 1600 * @see System#getProperty(java.lang.String) 1601 * @see System#getProperty(java.lang.String, java.lang.String) 1602 */ 1603 public static Long getLong(String nm, Long val) { 1604 String v = null; 1605 try { 1606 v = System.getProperty(nm); 1607 } catch (IllegalArgumentException | NullPointerException e) { 1608 } 1609 if (v != null) { 1610 try { 1611 return Long.decode(v); 1612 } catch (NumberFormatException e) { 1613 } 1614 } 1615 return val; 1616 } 1617 1618 /** 1619 * Compares two {@code Long} objects numerically. 1620 * 1621 * @param anotherLong the {@code Long} to be compared. 1622 * @return the value {@code 0} if this {@code Long} is 1623 * equal to the argument {@code Long}; a value less than 1624 * {@code 0} if this {@code Long} is numerically less 1625 * than the argument {@code Long}; and a value greater 1626 * than {@code 0} if this {@code Long} is numerically 1627 * greater than the argument {@code Long} (signed 1628 * comparison). 1629 * @since 1.2 1630 */ 1631 public int compareTo(Long anotherLong) { 1632 return compare(this.value, anotherLong.value); 1633 } 1634 1635 /** 1636 * Compares two {@code long} values numerically. 1637 * The value returned is identical to what would be returned by: 1638 * <pre> 1639 * Long.valueOf(x).compareTo(Long.valueOf(y)) 1640 * </pre> 1641 * 1642 * @param x the first {@code long} to compare 1643 * @param y the second {@code long} to compare 1644 * @return the value {@code 0} if {@code x == y}; 1645 * a value less than {@code 0} if {@code x < y}; and 1646 * a value greater than {@code 0} if {@code x > y} 1647 * @since 1.7 1648 */ 1649 public static int compare(long x, long y) { 1650 return (x < y) ? -1 : ((x == y) ? 0 : 1); 1651 } 1652 1653 /** 1654 * Compares two {@code long} values numerically treating the values 1655 * as unsigned. 1656 * 1657 * @param x the first {@code long} to compare 1658 * @param y the second {@code long} to compare 1659 * @return the value {@code 0} if {@code x == y}; a value less 1660 * than {@code 0} if {@code x < y} as unsigned values; and 1661 * a value greater than {@code 0} if {@code x > y} as 1662 * unsigned values 1663 * @since 1.8 1664 */ 1665 public static int compareUnsigned(long x, long y) { 1666 return compare(x + MIN_VALUE, y + MIN_VALUE); 1667 } 1668 1669 1670 /** 1671 * Returns the unsigned quotient of dividing the first argument by 1672 * the second where each argument and the result is interpreted as 1673 * an unsigned value. 1674 * 1675 * <p>Note that in two's complement arithmetic, the three other 1676 * basic arithmetic operations of add, subtract, and multiply are 1677 * bit-wise identical if the two operands are regarded as both 1678 * being signed or both being unsigned. Therefore separate {@code 1679 * addUnsigned}, etc. methods are not provided. 1680 * 1681 * @param dividend the value to be divided 1682 * @param divisor the value doing the dividing 1683 * @return the unsigned quotient of the first argument divided by 1684 * the second argument 1685 * @see #remainderUnsigned 1686 * @since 1.8 1687 */ 1688 public static long divideUnsigned(long dividend, long divisor) { 1689 if (divisor < 0L) { // signed comparison 1690 // Answer must be 0 or 1 depending on relative magnitude 1691 // of dividend and divisor. 1692 return (compareUnsigned(dividend, divisor)) < 0 ? 0L :1L; 1693 } 1694 1695 if (dividend > 0) // Both inputs non-negative 1696 return dividend/divisor; 1697 else { 1698 /* 1699 * For simple code, leveraging BigInteger. Longer and faster 1700 * code written directly in terms of operations on longs is 1701 * possible; see "Hacker's Delight" for divide and remainder 1702 * algorithms. 1703 */ 1704 return toUnsignedBigInteger(dividend). 1705 divide(toUnsignedBigInteger(divisor)).longValue(); 1706 } 1707 } 1708 1709 /** 1710 * Returns the unsigned remainder from dividing the first argument 1711 * by the second where each argument and the result is interpreted 1712 * as an unsigned value. 1713 * 1714 * @param dividend the value to be divided 1715 * @param divisor the value doing the dividing 1716 * @return the unsigned remainder of the first argument divided by 1717 * the second argument 1718 * @see #divideUnsigned 1719 * @since 1.8 1720 */ 1721 public static long remainderUnsigned(long dividend, long divisor) { 1722 if (dividend > 0 && divisor > 0) { // signed comparisons 1723 return dividend % divisor; 1724 } else { 1725 if (compareUnsigned(dividend, divisor) < 0) // Avoid explicit check for 0 divisor 1726 return dividend; 1727 else 1728 return toUnsignedBigInteger(dividend). 1729 remainder(toUnsignedBigInteger(divisor)).longValue(); 1730 } 1731 } 1732 1733 // Bit Twiddling 1734 1735 /** 1736 * The number of bits used to represent a {@code long} value in two's 1737 * complement binary form. 1738 * 1739 * @since 1.5 1740 */ 1741 @Native public static final int SIZE = 64; 1742 1743 /** 1744 * The number of bytes used to represent a {@code long} value in two's 1745 * complement binary form. 1746 * 1747 * @since 1.8 1748 */ 1749 public static final int BYTES = SIZE / Byte.SIZE; 1750 1751 /** 1752 * Returns a {@code long} value with at most a single one-bit, in the 1753 * position of the highest-order ("leftmost") one-bit in the specified 1754 * {@code long} value. Returns zero if the specified value has no 1755 * one-bits in its two's complement binary representation, that is, if it 1756 * is equal to zero. 1757 * 1758 * @param i the value whose highest one bit is to be computed 1759 * @return a {@code long} value with a single one-bit, in the position 1760 * of the highest-order one-bit in the specified value, or zero if 1761 * the specified value is itself equal to zero. 1762 * @since 1.5 1763 */ 1764 public static long highestOneBit(long i) { 1765 // HD, Figure 3-1 1766 i |= (i >> 1); 1767 i |= (i >> 2); 1768 i |= (i >> 4); 1769 i |= (i >> 8); 1770 i |= (i >> 16); 1771 i |= (i >> 32); 1772 return i - (i >>> 1); 1773 } 1774 1775 /** 1776 * Returns a {@code long} value with at most a single one-bit, in the 1777 * position of the lowest-order ("rightmost") one-bit in the specified 1778 * {@code long} value. Returns zero if the specified value has no 1779 * one-bits in its two's complement binary representation, that is, if it 1780 * is equal to zero. 1781 * 1782 * @param i the value whose lowest one bit is to be computed 1783 * @return a {@code long} value with a single one-bit, in the position 1784 * of the lowest-order one-bit in the specified value, or zero if 1785 * the specified value is itself equal to zero. 1786 * @since 1.5 1787 */ 1788 public static long lowestOneBit(long i) { 1789 // HD, Section 2-1 1790 return i & -i; 1791 } 1792 1793 /** 1794 * Returns the number of zero bits preceding the highest-order 1795 * ("leftmost") one-bit in the two's complement binary representation 1796 * of the specified {@code long} value. Returns 64 if the 1797 * specified value has no one-bits in its two's complement representation, 1798 * in other words if it is equal to zero. 1799 * 1800 * <p>Note that this method is closely related to the logarithm base 2. 1801 * For all positive {@code long} values x: 1802 * <ul> 1803 * <li>floor(log<sub>2</sub>(x)) = {@code 63 - numberOfLeadingZeros(x)} 1804 * <li>ceil(log<sub>2</sub>(x)) = {@code 64 - numberOfLeadingZeros(x - 1)} 1805 * </ul> 1806 * 1807 * @param i the value whose number of leading zeros is to be computed 1808 * @return the number of zero bits preceding the highest-order 1809 * ("leftmost") one-bit in the two's complement binary representation 1810 * of the specified {@code long} value, or 64 if the value 1811 * is equal to zero. 1812 * @since 1.5 1813 */ 1814 @HotSpotIntrinsicCandidate 1815 public static int numberOfLeadingZeros(long i) { 1816 // HD, Figure 5-6 1817 if (i == 0) 1818 return 64; 1819 int n = 1; 1820 int x = (int)(i >>> 32); 1821 if (x == 0) { n += 32; x = (int)i; } 1822 if (x >>> 16 == 0) { n += 16; x <<= 16; } 1823 if (x >>> 24 == 0) { n += 8; x <<= 8; } 1824 if (x >>> 28 == 0) { n += 4; x <<= 4; } 1825 if (x >>> 30 == 0) { n += 2; x <<= 2; } 1826 n -= x >>> 31; 1827 return n; 1828 } 1829 1830 /** 1831 * Returns the number of zero bits following the lowest-order ("rightmost") 1832 * one-bit in the two's complement binary representation of the specified 1833 * {@code long} value. Returns 64 if the specified value has no 1834 * one-bits in its two's complement representation, in other words if it is 1835 * equal to zero. 1836 * 1837 * @param i the value whose number of trailing zeros is to be computed 1838 * @return the number of zero bits following the lowest-order ("rightmost") 1839 * one-bit in the two's complement binary representation of the 1840 * specified {@code long} value, or 64 if the value is equal 1841 * to zero. 1842 * @since 1.5 1843 */ 1844 @HotSpotIntrinsicCandidate 1845 public static int numberOfTrailingZeros(long i) { 1846 // HD, Figure 5-14 1847 int x, y; 1848 if (i == 0) return 64; 1849 int n = 63; 1850 y = (int)i; if (y != 0) { n = n -32; x = y; } else x = (int)(i>>>32); 1851 y = x <<16; if (y != 0) { n = n -16; x = y; } 1852 y = x << 8; if (y != 0) { n = n - 8; x = y; } 1853 y = x << 4; if (y != 0) { n = n - 4; x = y; } 1854 y = x << 2; if (y != 0) { n = n - 2; x = y; } 1855 return n - ((x << 1) >>> 31); 1856 } 1857 1858 /** 1859 * Returns the number of one-bits in the two's complement binary 1860 * representation of the specified {@code long} value. This function is 1861 * sometimes referred to as the <i>population count</i>. 1862 * 1863 * @param i the value whose bits are to be counted 1864 * @return the number of one-bits in the two's complement binary 1865 * representation of the specified {@code long} value. 1866 * @since 1.5 1867 */ 1868 @HotSpotIntrinsicCandidate 1869 public static int bitCount(long i) { 1870 // HD, Figure 5-2 1871 i = i - ((i >>> 1) & 0x5555555555555555L); 1872 i = (i & 0x3333333333333333L) + ((i >>> 2) & 0x3333333333333333L); 1873 i = (i + (i >>> 4)) & 0x0f0f0f0f0f0f0f0fL; 1874 i = i + (i >>> 8); 1875 i = i + (i >>> 16); 1876 i = i + (i >>> 32); 1877 return (int)i & 0x7f; 1878 } 1879 1880 /** 1881 * Returns the value obtained by rotating the two's complement binary 1882 * representation of the specified {@code long} value left by the 1883 * specified number of bits. (Bits shifted out of the left hand, or 1884 * high-order, side reenter on the right, or low-order.) 1885 * 1886 * <p>Note that left rotation with a negative distance is equivalent to 1887 * right rotation: {@code rotateLeft(val, -distance) == rotateRight(val, 1888 * distance)}. Note also that rotation by any multiple of 64 is a 1889 * no-op, so all but the last six bits of the rotation distance can be 1890 * ignored, even if the distance is negative: {@code rotateLeft(val, 1891 * distance) == rotateLeft(val, distance & 0x3F)}. 1892 * 1893 * @param i the value whose bits are to be rotated left 1894 * @param distance the number of bit positions to rotate left 1895 * @return the value obtained by rotating the two's complement binary 1896 * representation of the specified {@code long} value left by the 1897 * specified number of bits. 1898 * @since 1.5 1899 */ 1900 public static long rotateLeft(long i, int distance) { 1901 return (i << distance) | (i >>> -distance); 1902 } 1903 1904 /** 1905 * Returns the value obtained by rotating the two's complement binary 1906 * representation of the specified {@code long} value right by the 1907 * specified number of bits. (Bits shifted out of the right hand, or 1908 * low-order, side reenter on the left, or high-order.) 1909 * 1910 * <p>Note that right rotation with a negative distance is equivalent to 1911 * left rotation: {@code rotateRight(val, -distance) == rotateLeft(val, 1912 * distance)}. Note also that rotation by any multiple of 64 is a 1913 * no-op, so all but the last six bits of the rotation distance can be 1914 * ignored, even if the distance is negative: {@code rotateRight(val, 1915 * distance) == rotateRight(val, distance & 0x3F)}. 1916 * 1917 * @param i the value whose bits are to be rotated right 1918 * @param distance the number of bit positions to rotate right 1919 * @return the value obtained by rotating the two's complement binary 1920 * representation of the specified {@code long} value right by the 1921 * specified number of bits. 1922 * @since 1.5 1923 */ 1924 public static long rotateRight(long i, int distance) { 1925 return (i >>> distance) | (i << -distance); 1926 } 1927 1928 /** 1929 * Returns the value obtained by reversing the order of the bits in the 1930 * two's complement binary representation of the specified {@code long} 1931 * value. 1932 * 1933 * @param i the value to be reversed 1934 * @return the value obtained by reversing order of the bits in the 1935 * specified {@code long} value. 1936 * @since 1.5 1937 */ 1938 public static long reverse(long i) { 1939 // HD, Figure 7-1 1940 i = (i & 0x5555555555555555L) << 1 | (i >>> 1) & 0x5555555555555555L; 1941 i = (i & 0x3333333333333333L) << 2 | (i >>> 2) & 0x3333333333333333L; 1942 i = (i & 0x0f0f0f0f0f0f0f0fL) << 4 | (i >>> 4) & 0x0f0f0f0f0f0f0f0fL; 1943 i = (i & 0x00ff00ff00ff00ffL) << 8 | (i >>> 8) & 0x00ff00ff00ff00ffL; 1944 i = (i << 48) | ((i & 0xffff0000L) << 16) | 1945 ((i >>> 16) & 0xffff0000L) | (i >>> 48); 1946 return i; 1947 } 1948 1949 /** 1950 * Returns the signum function of the specified {@code long} value. (The 1951 * return value is -1 if the specified value is negative; 0 if the 1952 * specified value is zero; and 1 if the specified value is positive.) 1953 * 1954 * @param i the value whose signum is to be computed 1955 * @return the signum function of the specified {@code long} value. 1956 * @since 1.5 1957 */ 1958 public static int signum(long i) { 1959 // HD, Section 2-7 1960 return (int) ((i >> 63) | (-i >>> 63)); 1961 } 1962 1963 /** 1964 * Returns the value obtained by reversing the order of the bytes in the 1965 * two's complement representation of the specified {@code long} value. 1966 * 1967 * @param i the value whose bytes are to be reversed 1968 * @return the value obtained by reversing the bytes in the specified 1969 * {@code long} value. 1970 * @since 1.5 1971 */ 1972 @HotSpotIntrinsicCandidate 1973 public static long reverseBytes(long i) { 1974 i = (i & 0x00ff00ff00ff00ffL) << 8 | (i >>> 8) & 0x00ff00ff00ff00ffL; 1975 return (i << 48) | ((i & 0xffff0000L) << 16) | 1976 ((i >>> 16) & 0xffff0000L) | (i >>> 48); 1977 } 1978 1979 /** 1980 * Adds two {@code long} values together as per the + operator. 1981 * 1982 * @param a the first operand 1983 * @param b the second operand 1984 * @return the sum of {@code a} and {@code b} 1985 * @see java.util.function.BinaryOperator 1986 * @since 1.8 1987 */ 1988 public static long sum(long a, long b) { 1989 return a + b; 1990 } 1991 1992 /** 1993 * Returns the greater of two {@code long} values 1994 * as if by calling {@link Math#max(long, long) Math.max}. 1995 * 1996 * @param a the first operand 1997 * @param b the second operand 1998 * @return the greater of {@code a} and {@code b} 1999 * @see java.util.function.BinaryOperator 2000 * @since 1.8 2001 */ 2002 public static long max(long a, long b) { 2003 return Math.max(a, b); 2004 } 2005 2006 /** 2007 * Returns the smaller of two {@code long} values 2008 * as if by calling {@link Math#min(long, long) Math.min}. 2009 * 2010 * @param a the first operand 2011 * @param b the second operand 2012 * @return the smaller of {@code a} and {@code b} 2013 * @see java.util.function.BinaryOperator 2014 * @since 1.8 2015 */ 2016 public static long min(long a, long b) { 2017 return Math.min(a, b); 2018 } 2019 2020 /** use serialVersionUID from JDK 1.0.2 for interoperability */ 2021 @Native private static final long serialVersionUID = 4290774380558885855L; 2022 }