1 /* 2 * Copyright (c) 1994, 2023, 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.lang.invoke.MethodHandles; 30 import java.lang.constant.Constable; 31 import java.lang.constant.ConstantDesc; 32 import java.math.*; 33 import java.util.Objects; 34 import java.util.Optional; 35 36 import jdk.internal.misc.CDS; 37 import jdk.internal.vm.annotation.ForceInline; 38 import jdk.internal.vm.annotation.IntrinsicCandidate; 39 import jdk.internal.vm.annotation.Stable; 40 41 import static java.lang.Character.digit; 42 import static java.lang.String.COMPACT_STRINGS; 43 import static java.lang.String.LATIN1; 44 import static java.lang.String.UTF16; 45 46 /** 47 * The {@code Long} class wraps a value of the primitive type {@code 48 * long} in an object. An object of type {@code Long} contains a 49 * single field whose type is {@code long}. 50 * 51 * <p> In addition, this class provides several methods for converting 52 * a {@code long} to a {@code String} and a {@code String} to a {@code 53 * long}, as well as other constants and methods useful when dealing 54 * with a {@code long}. 55 * 56 * <p>This is a <a href="{@docRoot}/java.base/java/lang/doc-files/ValueBased.html">value-based</a> 57 * class; programmers should treat instances that are 58 * {@linkplain #equals(Object) equal} as interchangeable and should not 59 * use instances for synchronization, or unpredictable behavior may 60 * occur. For example, in a future release, synchronization may fail. 61 * 62 * <p>Implementation note: The implementations of the "bit twiddling" 63 * methods (such as {@link #highestOneBit(long) highestOneBit} and 64 * {@link #numberOfTrailingZeros(long) numberOfTrailingZeros}) are 65 * based on material from Henry S. Warren, Jr.'s <i>Hacker's 66 * Delight</i>, (Addison Wesley, 2002). 67 * 68 * @author Lee Boynton 69 * @author Arthur van Hoff 70 * @author Josh Bloch 71 * @author Joseph D. Darcy 72 * @since 1.0 73 */ 74 @jdk.internal.MigratedValueClass 75 @jdk.internal.ValueBased 76 public final class Long extends Number 77 implements Comparable<Long>, Constable, ConstantDesc { 78 /** 79 * A constant holding the minimum value a {@code long} can 80 * have, -2<sup>63</sup>. 81 */ 82 @Native public static final long MIN_VALUE = 0x8000000000000000L; 83 84 /** 85 * A constant holding the maximum value a {@code long} can 86 * have, 2<sup>63</sup>-1. 87 */ 88 @Native public static final long MAX_VALUE = 0x7fffffffffffffffL; 89 90 /** 91 * The {@code Class} instance representing the primitive type 92 * {@code long}. 93 * 94 * @since 1.1 95 */ 96 @SuppressWarnings("unchecked") 97 public static final Class<Long> TYPE = (Class<Long>) Class.getPrimitiveClass("long"); 98 99 /** 100 * Returns a string representation of the first argument in the 101 * radix specified by the second argument. 102 * 103 * <p>If the radix is smaller than {@code Character.MIN_RADIX} 104 * or larger than {@code Character.MAX_RADIX}, then the radix 105 * {@code 10} is used instead. 106 * 107 * <p>If the first argument is negative, the first element of the 108 * result is the ASCII minus sign {@code '-'} 109 * ({@code '\u005Cu002d'}). If the first argument is not 110 * negative, no sign character appears in the result. 111 * 112 * <p>The remaining characters of the result represent the magnitude 113 * of the first argument. If the magnitude is zero, it is 114 * represented by a single zero character {@code '0'} 115 * ({@code '\u005Cu0030'}); otherwise, the first character of 116 * the representation of the magnitude will not be the zero 117 * character. The following ASCII characters are used as digits: 118 * 119 * <blockquote> 120 * {@code 0123456789abcdefghijklmnopqrstuvwxyz} 121 * </blockquote> 122 * 123 * These are {@code '\u005Cu0030'} through 124 * {@code '\u005Cu0039'} and {@code '\u005Cu0061'} through 125 * {@code '\u005Cu007a'}. If {@code radix} is 126 * <var>N</var>, then the first <var>N</var> of these characters 127 * are used as radix-<var>N</var> digits in the order shown. Thus, 128 * the digits for hexadecimal (radix 16) are 129 * {@code 0123456789abcdef}. If uppercase letters are 130 * desired, the {@link java.lang.String#toUpperCase()} method may 131 * be called on the result: 132 * 133 * <blockquote> 134 * {@code Long.toString(n, 16).toUpperCase()} 135 * </blockquote> 136 * 137 * @param i a {@code long} to be converted to a string. 138 * @param radix the radix to use in the string representation. 139 * @return a string representation of the argument in the specified radix. 140 * @see java.lang.Character#MAX_RADIX 141 * @see java.lang.Character#MIN_RADIX 142 */ 143 public static String toString(long i, int radix) { 144 if (radix < Character.MIN_RADIX || radix > Character.MAX_RADIX) 145 radix = 10; 146 if (radix == 10) 147 return toString(i); 148 149 if (COMPACT_STRINGS) { 150 byte[] buf = new byte[65]; 151 int charPos = 64; 152 boolean negative = (i < 0); 153 154 if (!negative) { 155 i = -i; 156 } 157 158 while (i <= -radix) { 159 buf[charPos--] = (byte)Integer.digits[(int)(-(i % radix))]; 160 i = i / radix; 161 } 162 buf[charPos] = (byte)Integer.digits[(int)(-i)]; 163 164 if (negative) { 165 buf[--charPos] = '-'; 166 } 167 return StringLatin1.newString(buf, charPos, (65 - charPos)); 168 } 169 return toStringUTF16(i, radix); 170 } 171 172 private static String toStringUTF16(long i, int radix) { 173 byte[] buf = new byte[65 * 2]; 174 int charPos = 64; 175 boolean negative = (i < 0); 176 if (!negative) { 177 i = -i; 178 } 179 while (i <= -radix) { 180 StringUTF16.putChar(buf, charPos--, Integer.digits[(int)(-(i % radix))]); 181 i = i / radix; 182 } 183 StringUTF16.putChar(buf, charPos, Integer.digits[(int)(-i)]); 184 if (negative) { 185 StringUTF16.putChar(buf, --charPos, '-'); 186 } 187 return StringUTF16.newString(buf, charPos, (65 - charPos)); 188 } 189 190 /** 191 * Returns a string representation of the first argument as an 192 * unsigned integer value in the radix specified by the second 193 * argument. 194 * 195 * <p>If the radix is smaller than {@code Character.MIN_RADIX} 196 * or larger than {@code Character.MAX_RADIX}, then the radix 197 * {@code 10} is used instead. 198 * 199 * <p>Note that since the first argument is treated as an unsigned 200 * value, no leading sign character is printed. 201 * 202 * <p>If the magnitude is zero, it is represented by a single zero 203 * character {@code '0'} ({@code '\u005Cu0030'}); otherwise, 204 * the first character of the representation of the magnitude will 205 * not be the zero character. 206 * 207 * <p>The behavior of radixes and the characters used as digits 208 * are the same as {@link #toString(long, int) toString}. 209 * 210 * @param i an integer to be converted to an unsigned string. 211 * @param radix the radix to use in the string representation. 212 * @return an unsigned string representation of the argument in the specified radix. 213 * @see #toString(long, int) 214 * @since 1.8 215 */ 216 public static String toUnsignedString(long i, int radix) { 217 if (i >= 0) 218 return toString(i, radix); 219 else { 220 return switch (radix) { 221 case 2 -> toBinaryString(i); 222 case 4 -> toUnsignedString0(i, 2); 223 case 8 -> toOctalString(i); 224 case 10 -> { 225 /* 226 * We can get the effect of an unsigned division by 10 227 * on a long value by first shifting right, yielding a 228 * positive value, and then dividing by 5. This 229 * allows the last digit and preceding digits to be 230 * isolated more quickly than by an initial conversion 231 * to BigInteger. 232 */ 233 long quot = (i >>> 1) / 5; 234 long rem = i - quot * 10; 235 yield toString(quot) + rem; 236 } 237 case 16 -> toHexString(i); 238 case 32 -> toUnsignedString0(i, 5); 239 default -> toUnsignedBigInteger(i).toString(radix); 240 }; 241 } 242 } 243 244 /** 245 * Return a BigInteger equal to the unsigned value of the 246 * argument. 247 */ 248 private static BigInteger toUnsignedBigInteger(long i) { 249 if (i >= 0L) 250 return BigInteger.valueOf(i); 251 else { 252 int upper = (int) (i >>> 32); 253 int lower = (int) i; 254 255 // return (upper << 32) + lower 256 return (BigInteger.valueOf(Integer.toUnsignedLong(upper))).shiftLeft(32). 257 add(BigInteger.valueOf(Integer.toUnsignedLong(lower))); 258 } 259 } 260 261 /** 262 * Returns a string representation of the {@code long} 263 * argument as an unsigned integer in base 16. 264 * 265 * <p>The unsigned {@code long} value is the argument plus 266 * 2<sup>64</sup> if the argument is negative; otherwise, it is 267 * equal to the argument. This value is converted to a string of 268 * ASCII digits in hexadecimal (base 16) with no extra 269 * leading {@code 0}s. 270 * 271 * <p>The value of the argument can be recovered from the returned 272 * string {@code s} by calling {@link 273 * Long#parseUnsignedLong(String, int) Long.parseUnsignedLong(s, 274 * 16)}. 275 * 276 * <p>If the unsigned magnitude is zero, it is represented by a 277 * single zero character {@code '0'} ({@code '\u005Cu0030'}); 278 * otherwise, the first character of the representation of the 279 * unsigned magnitude will not be the zero character. The 280 * following characters are used as hexadecimal digits: 281 * 282 * <blockquote> 283 * {@code 0123456789abcdef} 284 * </blockquote> 285 * 286 * These are the characters {@code '\u005Cu0030'} through 287 * {@code '\u005Cu0039'} and {@code '\u005Cu0061'} through 288 * {@code '\u005Cu0066'}. If uppercase letters are desired, 289 * the {@link java.lang.String#toUpperCase()} method may be called 290 * on the result: 291 * 292 * <blockquote> 293 * {@code Long.toHexString(n).toUpperCase()} 294 * </blockquote> 295 * 296 * @apiNote 297 * The {@link java.util.HexFormat} class provides formatting and parsing 298 * of byte arrays and primitives to return a string or adding to an {@link Appendable}. 299 * {@code HexFormat} formats and parses uppercase or lowercase hexadecimal characters, 300 * with leading zeros and for byte arrays includes for each byte 301 * a delimiter, prefix, and suffix. 302 * 303 * @param i a {@code long} to be converted to a string. 304 * @return the string representation of the unsigned {@code long} 305 * value represented by the argument in hexadecimal 306 * (base 16). 307 * @see java.util.HexFormat 308 * @see #parseUnsignedLong(String, int) 309 * @see #toUnsignedString(long, int) 310 * @since 1.0.2 311 */ 312 public static String toHexString(long i) { 313 return toUnsignedString0(i, 4); 314 } 315 316 /** 317 * Returns a string representation of the {@code long} 318 * argument as an unsigned integer in base 8. 319 * 320 * <p>The unsigned {@code long} value is the argument plus 321 * 2<sup>64</sup> if the argument is negative; otherwise, it is 322 * equal to the argument. This value is converted to a string of 323 * ASCII digits in octal (base 8) with no extra leading 324 * {@code 0}s. 325 * 326 * <p>The value of the argument can be recovered from the returned 327 * string {@code s} by calling {@link 328 * Long#parseUnsignedLong(String, int) Long.parseUnsignedLong(s, 329 * 8)}. 330 * 331 * <p>If the unsigned magnitude is zero, it is represented by a 332 * single zero character {@code '0'} ({@code '\u005Cu0030'}); 333 * otherwise, the first character of the representation of the 334 * unsigned magnitude will not be the zero character. The 335 * following characters are used as octal digits: 336 * 337 * <blockquote> 338 * {@code 01234567} 339 * </blockquote> 340 * 341 * These are the characters {@code '\u005Cu0030'} through 342 * {@code '\u005Cu0037'}. 343 * 344 * @param i a {@code long} to be converted to a string. 345 * @return the string representation of the unsigned {@code long} 346 * value represented by the argument in octal (base 8). 347 * @see #parseUnsignedLong(String, int) 348 * @see #toUnsignedString(long, int) 349 * @since 1.0.2 350 */ 351 public static String toOctalString(long i) { 352 return toUnsignedString0(i, 3); 353 } 354 355 /** 356 * Returns a string representation of the {@code long} 357 * argument as an unsigned integer in base 2. 358 * 359 * <p>The unsigned {@code long} value is the argument plus 360 * 2<sup>64</sup> if the argument is negative; otherwise, it is 361 * equal to the argument. This value is converted to a string of 362 * ASCII digits in binary (base 2) with no extra leading 363 * {@code 0}s. 364 * 365 * <p>The value of the argument can be recovered from the returned 366 * string {@code s} by calling {@link 367 * Long#parseUnsignedLong(String, int) Long.parseUnsignedLong(s, 368 * 2)}. 369 * 370 * <p>If the unsigned magnitude is zero, it is represented by a 371 * single zero character {@code '0'} ({@code '\u005Cu0030'}); 372 * otherwise, the first character of the representation of the 373 * unsigned magnitude will not be the zero character. The 374 * characters {@code '0'} ({@code '\u005Cu0030'}) and {@code 375 * '1'} ({@code '\u005Cu0031'}) are used as binary digits. 376 * 377 * @param i a {@code long} to be converted to a string. 378 * @return the string representation of the unsigned {@code long} 379 * value represented by the argument in binary (base 2). 380 * @see #parseUnsignedLong(String, int) 381 * @see #toUnsignedString(long, int) 382 * @since 1.0.2 383 */ 384 public static String toBinaryString(long i) { 385 return toUnsignedString0(i, 1); 386 } 387 388 /** 389 * Format a long (treated as unsigned) into a String. 390 * @param val the value to format 391 * @param shift the log2 of the base to format in (4 for hex, 3 for octal, 1 for binary) 392 */ 393 static String toUnsignedString0(long val, int shift) { 394 // assert shift > 0 && shift <=5 : "Illegal shift value"; 395 int mag = Long.SIZE - Long.numberOfLeadingZeros(val); 396 int chars = Math.max(((mag + (shift - 1)) / shift), 1); 397 if (COMPACT_STRINGS) { 398 byte[] buf = new byte[chars]; 399 formatUnsignedLong0(val, shift, buf, 0, chars); 400 return new String(buf, LATIN1); 401 } else { 402 byte[] buf = new byte[chars * 2]; 403 formatUnsignedLong0UTF16(val, shift, buf, 0, chars); 404 return new String(buf, UTF16); 405 } 406 } 407 408 /** 409 * Format a long (treated as unsigned) into a byte buffer (LATIN1 version). If 410 * {@code len} exceeds the formatted ASCII representation of {@code val}, 411 * {@code buf} will be padded with leading zeroes. 412 * 413 * @param val the unsigned long to format 414 * @param shift the log2 of the base to format in (4 for hex, 3 for octal, 1 for binary) 415 * @param buf the byte buffer to write to 416 * @param offset the offset in the destination buffer to start at 417 * @param len the number of characters to write 418 */ 419 private 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 /** 430 * Format a long (treated as unsigned) into a byte buffer (UTF16 version). If 431 * {@code len} exceeds the formatted ASCII representation of {@code val}, 432 * {@code buf} will be padded with leading zeroes. 433 * 434 * @param val the unsigned long to format 435 * @param shift the log2 of the base to format in (4 for hex, 3 for octal, 1 for binary) 436 * @param buf the byte buffer to write to 437 * @param offset the offset in the destination buffer to start at 438 * @param len the number of characters to write 439 */ 440 private static void formatUnsignedLong0UTF16(long val, int shift, byte[] buf, int offset, int len) { 441 int charPos = offset + len; 442 int radix = 1 << shift; 443 int mask = radix - 1; 444 do { 445 StringUTF16.putChar(buf, --charPos, Integer.digits[((int) val) & mask]); 446 val >>>= shift; 447 } while (charPos > offset); 448 } 449 450 /** 451 * Returns a {@code String} object representing the specified 452 * {@code long}. The argument is converted to signed decimal 453 * representation and returned as a string, exactly as if the 454 * argument and the radix 10 were given as arguments to the {@link 455 * #toString(long, int)} method. 456 * 457 * @param i a {@code long} to be converted. 458 * @return a string representation of the argument in base 10. 459 */ 460 public static String toString(long i) { 461 int size = stringSize(i); 462 if (COMPACT_STRINGS) { 463 byte[] buf = new byte[size]; 464 StringLatin1.getChars(i, size, buf); 465 return new String(buf, LATIN1); 466 } else { 467 byte[] buf = new byte[size * 2]; 468 StringUTF16.getChars(i, size, buf); 469 return new String(buf, UTF16); 470 } 471 } 472 473 /** 474 * Returns a string representation of the argument as an unsigned 475 * decimal value. 476 * 477 * The argument is converted to unsigned decimal representation 478 * and returned as a string exactly as if the argument and radix 479 * 10 were given as arguments to the {@link #toUnsignedString(long, 480 * int)} method. 481 * 482 * @param i an integer to be converted to an unsigned string. 483 * @return an unsigned string representation of the argument. 484 * @see #toUnsignedString(long, int) 485 * @since 1.8 486 */ 487 public static String toUnsignedString(long i) { 488 return toUnsignedString(i, 10); 489 } 490 491 /** 492 * Returns the string representation size for a given long value. 493 * 494 * @param x long value 495 * @return string size 496 * 497 * @implNote There are other ways to compute this: e.g. binary search, 498 * but values are biased heavily towards zero, and therefore linear search 499 * wins. The iteration results are also routinely inlined in the generated 500 * code after loop unrolling. 501 */ 502 static int stringSize(long x) { 503 int d = 1; 504 if (x >= 0) { 505 d = 0; 506 x = -x; 507 } 508 long p = -10; 509 for (int i = 1; i < 19; i++) { 510 if (x > p) 511 return i + d; 512 p = 10 * p; 513 } 514 return 19 + d; 515 } 516 517 /** 518 * Parses the string argument as a signed {@code long} in the 519 * radix specified by the second argument. The characters in the 520 * string must all be digits of the specified radix (as determined 521 * by whether {@link java.lang.Character#digit(char, int)} returns 522 * a nonnegative value), except that the first character may be an 523 * ASCII minus sign {@code '-'} ({@code '\u005Cu002D'}) to 524 * indicate a negative value or an ASCII plus sign {@code '+'} 525 * ({@code '\u005Cu002B'}) to indicate a positive value. The 526 * resulting {@code long} value is returned. 527 * 528 * <p>Note that neither the character {@code L} 529 * ({@code '\u005Cu004C'}) nor {@code l} 530 * ({@code '\u005Cu006C'}) is permitted to appear at the end 531 * of the string as a type indicator, as would be permitted in 532 * Java programming language source code - except that either 533 * {@code L} or {@code l} may appear as a digit for a 534 * radix greater than or equal to 22. 535 * 536 * <p>An exception of type {@code NumberFormatException} is 537 * thrown if any of the following situations occurs: 538 * <ul> 539 * 540 * <li>The first argument is {@code null} or is a string of 541 * length zero. 542 * 543 * <li>The {@code radix} is either smaller than {@link 544 * java.lang.Character#MIN_RADIX} or larger than {@link 545 * java.lang.Character#MAX_RADIX}. 546 * 547 * <li>Any character of the string is not a digit of the specified 548 * radix, except that the first character may be a minus sign 549 * {@code '-'} ({@code '\u005Cu002d'}) or plus sign {@code 550 * '+'} ({@code '\u005Cu002B'}) provided that the string is 551 * longer than length 1. 552 * 553 * <li>The value represented by the string is not a value of type 554 * {@code long}. 555 * </ul> 556 * 557 * <p>Examples: 558 * <blockquote><pre> 559 * parseLong("0", 10) returns 0L 560 * parseLong("473", 10) returns 473L 561 * parseLong("+42", 10) returns 42L 562 * parseLong("-0", 10) returns 0L 563 * parseLong("-FF", 16) returns -255L 564 * parseLong("1100110", 2) returns 102L 565 * parseLong("99", 8) throws a NumberFormatException 566 * parseLong("Hazelnut", 10) throws a NumberFormatException 567 * parseLong("Hazelnut", 36) returns 1356099454469L 568 * </pre></blockquote> 569 * 570 * @param s the {@code String} containing the 571 * {@code long} representation to be parsed. 572 * @param radix the radix to be used while parsing {@code s}. 573 * @return the {@code long} represented by the string argument in 574 * the specified radix. 575 * @throws NumberFormatException if the string does not contain a 576 * parsable {@code long}. 577 */ 578 public static long parseLong(String s, int radix) 579 throws NumberFormatException { 580 if (s == null) { 581 throw new NumberFormatException("Cannot parse null string"); 582 } 583 584 if (radix < Character.MIN_RADIX) { 585 throw new NumberFormatException(String.format( 586 "radix %s less than Character.MIN_RADIX", radix)); 587 } 588 589 if (radix > Character.MAX_RADIX) { 590 throw new NumberFormatException(String.format( 591 "radix %s greater than Character.MAX_RADIX", radix)); 592 } 593 594 int len = s.length(); 595 if (len == 0) { 596 throw NumberFormatException.forInputString("", radix); 597 } 598 int digit = ~0xFF; 599 int i = 0; 600 char firstChar = s.charAt(i++); 601 if (firstChar != '-' && firstChar != '+') { 602 digit = digit(firstChar, radix); 603 } 604 if (digit >= 0 || digit == ~0xFF && len > 1) { 605 long limit = firstChar != '-' ? MIN_VALUE + 1 : MIN_VALUE; 606 long multmin = limit / radix; 607 long result = -(digit & 0xFF); 608 boolean inRange = true; 609 /* Accumulating negatively avoids surprises near MAX_VALUE */ 610 while (i < len && (digit = digit(s.charAt(i++), radix)) >= 0 611 && (inRange = result > multmin 612 || result == multmin && digit <= (int) (radix * multmin - limit))) { 613 result = radix * result - digit; 614 } 615 if (inRange && i == len && digit >= 0) { 616 return firstChar != '-' ? -result : result; 617 } 618 } 619 throw NumberFormatException.forInputString(s, radix); 620 } 621 622 /** 623 * Parses the {@link CharSequence} argument as a signed {@code long} in 624 * the specified {@code radix}, beginning at the specified 625 * {@code beginIndex} and extending to {@code endIndex - 1}. 626 * 627 * <p>The method does not take steps to guard against the 628 * {@code CharSequence} being mutated while parsing. 629 * 630 * @param s the {@code CharSequence} containing the {@code long} 631 * representation to be parsed 632 * @param beginIndex the beginning index, inclusive. 633 * @param endIndex the ending index, exclusive. 634 * @param radix the radix to be used while parsing {@code s}. 635 * @return the signed {@code long} represented by the subsequence in 636 * the specified radix. 637 * @throws NullPointerException if {@code s} is null. 638 * @throws IndexOutOfBoundsException if {@code beginIndex} is 639 * negative, or if {@code beginIndex} is greater than 640 * {@code endIndex} or if {@code endIndex} is greater than 641 * {@code s.length()}. 642 * @throws NumberFormatException if the {@code CharSequence} does not 643 * contain a parsable {@code long} in the specified 644 * {@code radix}, or if {@code radix} is either smaller than 645 * {@link java.lang.Character#MIN_RADIX} or larger than 646 * {@link java.lang.Character#MAX_RADIX}. 647 * @since 9 648 */ 649 public static long parseLong(CharSequence s, int beginIndex, int endIndex, int radix) 650 throws NumberFormatException { 651 Objects.requireNonNull(s); 652 Objects.checkFromToIndex(beginIndex, endIndex, s.length()); 653 654 if (radix < Character.MIN_RADIX) { 655 throw new NumberFormatException(String.format( 656 "radix %s less than Character.MIN_RADIX", radix)); 657 } 658 659 if (radix > Character.MAX_RADIX) { 660 throw new NumberFormatException(String.format( 661 "radix %s greater than Character.MAX_RADIX", radix)); 662 } 663 664 /* 665 * While s can be concurrently modified, it is ensured that each 666 * of its characters is read at most once, from lower to higher indices. 667 * This is obtained by reading them using the pattern s.charAt(i++), 668 * and by not updating i anywhere else. 669 */ 670 if (beginIndex == endIndex) { 671 throw NumberFormatException.forInputString("", radix); 672 } 673 int digit = ~0xFF; // ~0xFF means firstChar char is sign 674 int i = beginIndex; 675 char firstChar = s.charAt(i++); 676 if (firstChar != '-' && firstChar != '+') { 677 digit = digit(firstChar, radix); 678 } 679 if (digit >= 0 || digit == ~0xFF && endIndex - beginIndex > 1) { 680 long limit = firstChar != '-' ? MIN_VALUE + 1 : MIN_VALUE; 681 long multmin = limit / radix; 682 long result = -(digit & 0xFF); 683 boolean inRange = true; 684 /* Accumulating negatively avoids surprises near MAX_VALUE */ 685 while (i < endIndex && (digit = digit(s.charAt(i++), radix)) >= 0 686 && (inRange = result > multmin 687 || result == multmin && digit <= (int) (radix * multmin - limit))) { 688 result = radix * result - digit; 689 } 690 if (inRange && i == endIndex && digit >= 0) { 691 return firstChar != '-' ? -result : result; 692 } 693 } 694 throw NumberFormatException.forCharSequence(s, beginIndex, 695 endIndex, i - (digit < -1 ? 0 : 1)); 696 } 697 698 /** 699 * Parses the string argument as a signed decimal {@code long}. 700 * The characters in the string must all be decimal digits, except 701 * that the first character may be an ASCII minus sign {@code '-'} 702 * ({@code \u005Cu002D'}) to indicate a negative value or an 703 * ASCII plus sign {@code '+'} ({@code '\u005Cu002B'}) to 704 * indicate a positive value. The resulting {@code long} value is 705 * returned, exactly as if the argument and the radix {@code 10} 706 * were given as arguments to the {@link 707 * #parseLong(java.lang.String, int)} method. 708 * 709 * <p>Note that neither the character {@code L} 710 * ({@code '\u005Cu004C'}) nor {@code l} 711 * ({@code '\u005Cu006C'}) is permitted to appear at the end 712 * of the string as a type indicator, as would be permitted in 713 * Java programming language source code. 714 * 715 * @param s a {@code String} containing the {@code long} 716 * representation to be parsed 717 * @return the {@code long} represented by the argument in 718 * decimal. 719 * @throws NumberFormatException if the string does not contain a 720 * parsable {@code long}. 721 */ 722 public static long parseLong(String s) throws NumberFormatException { 723 return parseLong(s, 10); 724 } 725 726 /** 727 * Parses the string argument as an unsigned {@code long} in the 728 * radix specified by the second argument. An unsigned integer 729 * maps the values usually associated with negative numbers to 730 * positive numbers larger than {@code MAX_VALUE}. 731 * 732 * The characters in the string must all be digits of the 733 * specified radix (as determined by whether {@link 734 * java.lang.Character#digit(char, int)} returns a nonnegative 735 * value), except that the first character may be an ASCII plus 736 * sign {@code '+'} ({@code '\u005Cu002B'}). The resulting 737 * integer value is returned. 738 * 739 * <p>An exception of type {@code NumberFormatException} is 740 * thrown if any of the following situations occurs: 741 * <ul> 742 * <li>The first argument is {@code null} or is a string of 743 * length zero. 744 * 745 * <li>The radix is either smaller than 746 * {@link java.lang.Character#MIN_RADIX} or 747 * larger than {@link java.lang.Character#MAX_RADIX}. 748 * 749 * <li>Any character of the string is not a digit of the specified 750 * radix, except that the first character may be a plus sign 751 * {@code '+'} ({@code '\u005Cu002B'}) provided that the 752 * string is longer than length 1. 753 * 754 * <li>The value represented by the string is larger than the 755 * largest unsigned {@code long}, 2<sup>64</sup>-1. 756 * 757 * </ul> 758 * 759 * 760 * @param s the {@code String} containing the unsigned integer 761 * representation to be parsed 762 * @param radix the radix to be used while parsing {@code s}. 763 * @return the unsigned {@code long} represented by the string 764 * argument in the specified radix. 765 * @throws NumberFormatException if the {@code String} 766 * does not contain a parsable {@code long}. 767 * @since 1.8 768 */ 769 public static long parseUnsignedLong(String s, int radix) 770 throws NumberFormatException { 771 if (s == null) { 772 throw new NumberFormatException("Cannot parse null string"); 773 } 774 775 if (radix < Character.MIN_RADIX) { 776 throw new NumberFormatException(String.format( 777 "radix %s less than Character.MIN_RADIX", radix)); 778 } 779 780 if (radix > Character.MAX_RADIX) { 781 throw new NumberFormatException(String.format( 782 "radix %s greater than Character.MAX_RADIX", radix)); 783 } 784 785 int len = s.length(); 786 if (len == 0) { 787 throw NumberFormatException.forInputString(s, radix); 788 } 789 int i = 0; 790 char firstChar = s.charAt(i++); 791 if (firstChar == '-') { 792 throw new NumberFormatException(String.format( 793 "Illegal leading minus sign on unsigned string %s.", s)); 794 } 795 int digit = ~0xFF; 796 if (firstChar != '+') { 797 digit = digit(firstChar, radix); 798 } 799 if (digit >= 0 || digit == ~0xFF && len > 1) { 800 long multmax = divideUnsigned(-1L, radix); // -1L is max unsigned long 801 long result = digit & 0xFF; 802 boolean inRange = true; 803 while (i < len && (digit = digit(s.charAt(i++), radix)) >= 0 804 && (inRange = compareUnsigned(result, multmax) < 0 805 || result == multmax && digit < (int) (-radix * multmax))) { 806 result = radix * result + digit; 807 } 808 if (inRange && i == len && digit >= 0) { 809 return result; 810 } 811 } 812 if (digit < 0) { 813 throw NumberFormatException.forInputString(s, radix); 814 } 815 throw new NumberFormatException(String.format( 816 "String value %s exceeds range of unsigned long.", s)); 817 } 818 819 /** 820 * Parses the {@link CharSequence} argument as an unsigned {@code long} in 821 * the specified {@code radix}, beginning at the specified 822 * {@code beginIndex} and extending to {@code endIndex - 1}. 823 * 824 * <p>The method does not take steps to guard against the 825 * {@code CharSequence} being mutated while parsing. 826 * 827 * @param s the {@code CharSequence} containing the unsigned 828 * {@code long} representation to be parsed 829 * @param beginIndex the beginning index, inclusive. 830 * @param endIndex the ending index, exclusive. 831 * @param radix the radix to be used while parsing {@code s}. 832 * @return the unsigned {@code long} represented by the subsequence in 833 * the specified radix. 834 * @throws NullPointerException if {@code s} is null. 835 * @throws IndexOutOfBoundsException if {@code beginIndex} is 836 * negative, or if {@code beginIndex} is greater than 837 * {@code endIndex} or if {@code endIndex} is greater than 838 * {@code s.length()}. 839 * @throws NumberFormatException if the {@code CharSequence} does not 840 * contain a parsable unsigned {@code long} in the specified 841 * {@code radix}, or if {@code radix} is either smaller than 842 * {@link java.lang.Character#MIN_RADIX} or larger than 843 * {@link java.lang.Character#MAX_RADIX}. 844 * @since 9 845 */ 846 public static long parseUnsignedLong(CharSequence s, int beginIndex, int endIndex, int radix) 847 throws NumberFormatException { 848 Objects.requireNonNull(s); 849 Objects.checkFromToIndex(beginIndex, endIndex, s.length()); 850 851 if (radix < Character.MIN_RADIX) { 852 throw new NumberFormatException(String.format( 853 "radix %s less than Character.MIN_RADIX", radix)); 854 } 855 856 if (radix > Character.MAX_RADIX) { 857 throw new NumberFormatException(String.format( 858 "radix %s greater than Character.MAX_RADIX", radix)); 859 } 860 861 /* 862 * While s can be concurrently modified, it is ensured that each 863 * of its characters is read at most once, from lower to higher indices. 864 * This is obtained by reading them using the pattern s.charAt(i++), 865 * and by not updating i anywhere else. 866 */ 867 if (beginIndex == endIndex) { 868 throw NumberFormatException.forInputString("", radix); 869 } 870 int i = beginIndex; 871 char firstChar = s.charAt(i++); 872 if (firstChar == '-') { 873 throw new NumberFormatException( 874 "Illegal leading minus sign on unsigned string " + s + "."); 875 } 876 int digit = ~0xFF; 877 if (firstChar != '+') { 878 digit = digit(firstChar, radix); 879 } 880 if (digit >= 0 || digit == ~0xFF && endIndex - beginIndex > 1) { 881 long multmax = divideUnsigned(-1L, radix); // -1L is max unsigned long 882 long result = digit & 0xFF; 883 boolean inRange = true; 884 while (i < endIndex && (digit = digit(s.charAt(i++), radix)) >= 0 885 && (inRange = compareUnsigned(result, multmax) < 0 886 || result == multmax && digit < (int) (-radix * multmax))) { 887 result = radix * result + digit; 888 } 889 if (inRange && i == endIndex && digit >= 0) { 890 return result; 891 } 892 } 893 if (digit < 0) { 894 throw NumberFormatException.forCharSequence(s, beginIndex, 895 endIndex, i - (digit < -1 ? 0 : 1)); 896 } 897 throw new NumberFormatException(String.format( 898 "String value %s exceeds range of unsigned long.", s)); 899 } 900 901 /** 902 * Parses the string argument as an unsigned decimal {@code long}. The 903 * characters in the string must all be decimal digits, except 904 * that the first character may be an ASCII plus sign {@code 905 * '+'} ({@code '\u005Cu002B'}). The resulting integer value 906 * is returned, exactly as if the argument and the radix 10 were 907 * given as arguments to the {@link 908 * #parseUnsignedLong(java.lang.String, int)} method. 909 * 910 * @param s a {@code String} containing the unsigned {@code long} 911 * representation to be parsed 912 * @return the unsigned {@code long} value represented by the decimal string argument 913 * @throws NumberFormatException if the string does not contain a 914 * parsable unsigned integer. 915 * @since 1.8 916 */ 917 public static long parseUnsignedLong(String s) throws NumberFormatException { 918 return parseUnsignedLong(s, 10); 919 } 920 921 /** 922 * Returns a {@code Long} object holding the value 923 * extracted from the specified {@code String} when parsed 924 * with the radix given by the second argument. The first 925 * argument is interpreted as representing a signed 926 * {@code long} in the radix specified by the second 927 * argument, exactly as if the arguments were given to the {@link 928 * #parseLong(java.lang.String, int)} method. The result is a 929 * {@code Long} object that represents the {@code long} 930 * value specified by the string. 931 * 932 * <p>In other words, this method returns a {@code Long} object equal 933 * to the value of: 934 * 935 * <blockquote> 936 * {@code Long.valueOf(Long.parseLong(s, radix))} 937 * </blockquote> 938 * 939 * @param s the string to be parsed 940 * @param radix the radix to be used in interpreting {@code s} 941 * @return a {@code Long} object holding the value 942 * represented by the string argument in the specified 943 * radix. 944 * @throws NumberFormatException If the {@code String} does not 945 * contain a parsable {@code long}. 946 */ 947 public static Long valueOf(String s, int radix) throws NumberFormatException { 948 return Long.valueOf(parseLong(s, radix)); 949 } 950 951 /** 952 * Returns a {@code Long} object holding the value 953 * of the specified {@code String}. The argument is 954 * interpreted as representing a signed decimal {@code long}, 955 * exactly as if the argument were given to the {@link 956 * #parseLong(java.lang.String)} method. The result is a 957 * {@code Long} object that represents the integer value 958 * specified by the string. 959 * 960 * <p>In other words, this method returns a {@code Long} object 961 * equal to the value of: 962 * 963 * <blockquote> 964 * {@code Long.valueOf(Long.parseLong(s))} 965 * </blockquote> 966 * 967 * @param s the string to be parsed. 968 * @return a {@code Long} object holding the value 969 * represented by the string argument. 970 * @throws NumberFormatException If the string cannot be parsed 971 * as a {@code long}. 972 */ 973 public static Long valueOf(String s) throws NumberFormatException 974 { 975 return Long.valueOf(parseLong(s, 10)); 976 } 977 978 private static final class LongCache { 979 private LongCache() {} 980 981 @Stable 982 static final Long[] cache; 983 static Long[] archivedCache; 984 985 static { 986 int size = -(-128) + 127 + 1; 987 988 // Load and use the archived cache if it exists 989 CDS.initializeFromArchive(LongCache.class); 990 if (archivedCache == null || archivedCache.length != size) { 991 Long[] c = new Long[size]; 992 long value = -128; 993 for(int i = 0; i < size; i++) { 994 c[i] = new Long(value++); 995 } 996 archivedCache = c; 997 } 998 cache = archivedCache; 999 } 1000 } 1001 1002 /** 1003 * Returns a {@code Long} instance representing the specified 1004 * {@code long} value. 1005 * If a new {@code Long} instance is not required, this method 1006 * should generally be used in preference to the constructor 1007 * {@link #Long(long)}, as this method is likely to yield 1008 * significantly better space and time performance by caching 1009 * frequently requested values. 1010 * 1011 * This method will always cache values in the range -128 to 127, 1012 * inclusive, and may cache other values outside of this range. 1013 * 1014 * @param l a long value. 1015 * @return a {@code Long} instance representing {@code l}. 1016 * @since 1.5 1017 */ 1018 @IntrinsicCandidate 1019 public static Long valueOf(long l) { 1020 final int offset = 128; 1021 if (l >= -128 && l <= 127) { // will cache 1022 return LongCache.cache[(int)l + offset]; 1023 } 1024 return new Long(l); 1025 } 1026 1027 /** 1028 * Decodes a {@code String} into a {@code Long}. 1029 * Accepts decimal, hexadecimal, and octal numbers given by the 1030 * following grammar: 1031 * 1032 * <blockquote> 1033 * <dl> 1034 * <dt><i>DecodableString:</i> 1035 * <dd><i>Sign<sub>opt</sub> DecimalNumeral</i> 1036 * <dd><i>Sign<sub>opt</sub></i> {@code 0x} <i>HexDigits</i> 1037 * <dd><i>Sign<sub>opt</sub></i> {@code 0X} <i>HexDigits</i> 1038 * <dd><i>Sign<sub>opt</sub></i> {@code #} <i>HexDigits</i> 1039 * <dd><i>Sign<sub>opt</sub></i> {@code 0} <i>OctalDigits</i> 1040 * 1041 * <dt><i>Sign:</i> 1042 * <dd>{@code -} 1043 * <dd>{@code +} 1044 * </dl> 1045 * </blockquote> 1046 * 1047 * <i>DecimalNumeral</i>, <i>HexDigits</i>, and <i>OctalDigits</i> 1048 * are as defined in section {@jls 3.10.1} of 1049 * <cite>The Java Language Specification</cite>, 1050 * except that underscores are not accepted between digits. 1051 * 1052 * <p>The sequence of characters following an optional 1053 * sign and/or radix specifier ("{@code 0x}", "{@code 0X}", 1054 * "{@code #}", or leading zero) is parsed as by the {@code 1055 * Long.parseLong} method with the indicated radix (10, 16, or 8). 1056 * This sequence of characters must represent a positive value or 1057 * a {@link NumberFormatException} will be thrown. The result is 1058 * negated if first character of the specified {@code String} is 1059 * the minus sign. No whitespace characters are permitted in the 1060 * {@code String}. 1061 * 1062 * @param nm the {@code String} to decode. 1063 * @return a {@code Long} object holding the {@code long} 1064 * value represented by {@code nm} 1065 * @throws NumberFormatException if the {@code String} does not 1066 * contain a parsable {@code long}. 1067 * @see java.lang.Long#parseLong(String, int) 1068 * @since 1.2 1069 */ 1070 public static Long decode(String nm) throws NumberFormatException { 1071 int radix = 10; 1072 int index = 0; 1073 boolean negative = false; 1074 long result; 1075 1076 if (nm.isEmpty()) 1077 throw new NumberFormatException("Zero length string"); 1078 char firstChar = nm.charAt(0); 1079 // Handle sign, if present 1080 if (firstChar == '-') { 1081 negative = true; 1082 index++; 1083 } else if (firstChar == '+') 1084 index++; 1085 1086 // Handle radix specifier, if present 1087 if (nm.startsWith("0x", index) || nm.startsWith("0X", index)) { 1088 index += 2; 1089 radix = 16; 1090 } 1091 else if (nm.startsWith("#", index)) { 1092 index ++; 1093 radix = 16; 1094 } 1095 else if (nm.startsWith("0", index) && nm.length() > 1 + index) { 1096 index ++; 1097 radix = 8; 1098 } 1099 1100 if (nm.startsWith("-", index) || nm.startsWith("+", index)) 1101 throw new NumberFormatException("Sign character in wrong position"); 1102 1103 try { 1104 result = parseLong(nm, index, nm.length(), radix); 1105 result = negative ? -result : result; 1106 } catch (NumberFormatException e) { 1107 // If number is Long.MIN_VALUE, we'll end up here. The next line 1108 // handles this case, and causes any genuine format error to be 1109 // rethrown. 1110 String constant = negative ? ("-" + nm.substring(index)) 1111 : nm.substring(index); 1112 result = parseLong(constant, radix); 1113 } 1114 return result; 1115 } 1116 1117 /** 1118 * The value of the {@code Long}. 1119 * 1120 * @serial 1121 */ 1122 private final long value; 1123 1124 /** 1125 * Constructs a newly allocated {@code Long} object that 1126 * represents the specified {@code long} argument. 1127 * 1128 * @param value the value to be represented by the 1129 * {@code Long} object. 1130 * 1131 * @deprecated 1132 * It is rarely appropriate to use this constructor. The static factory 1133 * {@link #valueOf(long)} is generally a better choice, as it is 1134 * likely to yield significantly better space and time performance. 1135 */ 1136 @Deprecated(since="9", forRemoval = true) 1137 public Long(long value) { 1138 this.value = value; 1139 } 1140 1141 /** 1142 * Constructs a newly allocated {@code Long} object that 1143 * represents the {@code long} value indicated by the 1144 * {@code String} parameter. The string is converted to a 1145 * {@code long} value in exactly the manner used by the 1146 * {@code parseLong} method for radix 10. 1147 * 1148 * @param s the {@code String} to be converted to a 1149 * {@code Long}. 1150 * @throws NumberFormatException if the {@code String} does not 1151 * contain a parsable {@code long}. 1152 * 1153 * @deprecated 1154 * It is rarely appropriate to use this constructor. 1155 * Use {@link #parseLong(String)} to convert a string to a 1156 * {@code long} primitive, or use {@link #valueOf(String)} 1157 * to convert a string to a {@code Long} object. 1158 */ 1159 @Deprecated(since="9", forRemoval = true) 1160 public Long(String s) throws NumberFormatException { 1161 this.value = parseLong(s, 10); 1162 } 1163 1164 /** 1165 * Returns the value of this {@code Long} as a {@code byte} after 1166 * a narrowing primitive conversion. 1167 * @jls 5.1.3 Narrowing Primitive Conversion 1168 */ 1169 public byte byteValue() { 1170 return (byte)value; 1171 } 1172 1173 /** 1174 * Returns the value of this {@code Long} as a {@code short} after 1175 * a narrowing primitive conversion. 1176 * @jls 5.1.3 Narrowing Primitive Conversion 1177 */ 1178 public short shortValue() { 1179 return (short)value; 1180 } 1181 1182 /** 1183 * Returns the value of this {@code Long} as an {@code int} after 1184 * a narrowing primitive conversion. 1185 * @jls 5.1.3 Narrowing Primitive Conversion 1186 */ 1187 public int intValue() { 1188 return (int)value; 1189 } 1190 1191 /** 1192 * Returns the value of this {@code Long} as a 1193 * {@code long} value. 1194 */ 1195 @IntrinsicCandidate 1196 public long longValue() { 1197 return value; 1198 } 1199 1200 /** 1201 * Returns the value of this {@code Long} as a {@code float} after 1202 * a widening primitive conversion. 1203 * @jls 5.1.2 Widening Primitive Conversion 1204 */ 1205 public float floatValue() { 1206 return (float)value; 1207 } 1208 1209 /** 1210 * Returns the value of this {@code Long} as a {@code double} 1211 * after a widening primitive conversion. 1212 * @jls 5.1.2 Widening Primitive Conversion 1213 */ 1214 public double doubleValue() { 1215 return (double)value; 1216 } 1217 1218 /** 1219 * Returns a {@code String} object representing this 1220 * {@code Long}'s value. The value is converted to signed 1221 * decimal representation and returned as a string, exactly as if 1222 * the {@code long} value were given as an argument to the 1223 * {@link java.lang.Long#toString(long)} method. 1224 * 1225 * @return a string representation of the value of this object in 1226 * base 10. 1227 */ 1228 public String toString() { 1229 return toString(value); 1230 } 1231 1232 /** 1233 * Returns a hash code for this {@code Long}. The result is 1234 * the exclusive OR of the two halves of the primitive 1235 * {@code long} value held by this {@code Long} 1236 * object. That is, the hashcode is the value of the expression: 1237 * 1238 * <blockquote> 1239 * {@code (int)(this.longValue()^(this.longValue()>>>32))} 1240 * </blockquote> 1241 * 1242 * @return a hash code value for this object. 1243 */ 1244 @Override 1245 public int hashCode() { 1246 return Long.hashCode(value); 1247 } 1248 1249 /** 1250 * Returns a hash code for a {@code long} value; compatible with 1251 * {@code Long.hashCode()}. 1252 * 1253 * @param value the value to hash 1254 * @return a hash code value for a {@code long} value. 1255 * @since 1.8 1256 */ 1257 public static int hashCode(long value) { 1258 return (int)(value ^ (value >>> 32)); 1259 } 1260 1261 /** 1262 * Compares this object to the specified object. The result is 1263 * {@code true} if and only if the argument is not 1264 * {@code null} and is a {@code Long} object that 1265 * contains the same {@code long} value as this object. 1266 * 1267 * @param obj the object to compare with. 1268 * @return {@code true} if the objects are the same; 1269 * {@code false} otherwise. 1270 */ 1271 public boolean equals(Object obj) { 1272 if (obj instanceof Long) { 1273 return value == ((Long)obj).longValue(); 1274 } 1275 return false; 1276 } 1277 1278 /** 1279 * Determines the {@code long} value of the system property 1280 * with the specified name. 1281 * 1282 * <p>The first argument is treated as the name of a system 1283 * property. System properties are accessible through the {@link 1284 * java.lang.System#getProperty(java.lang.String)} method. The 1285 * string value of this property is then interpreted as a {@code 1286 * long} value using the grammar supported by {@link Long#decode decode} 1287 * and a {@code Long} object representing this value is returned. 1288 * 1289 * <p>If there is no property with the specified name, if the 1290 * specified name is empty or {@code null}, or if the property 1291 * does not have the correct numeric format, then {@code null} is 1292 * returned. 1293 * 1294 * <p>In other words, this method returns a {@code Long} object 1295 * equal to the value of: 1296 * 1297 * <blockquote> 1298 * {@code getLong(nm, null)} 1299 * </blockquote> 1300 * 1301 * @param nm property name. 1302 * @return the {@code Long} value of the property. 1303 * @throws SecurityException for the same reasons as 1304 * {@link System#getProperty(String) System.getProperty} 1305 * @see java.lang.System#getProperty(java.lang.String) 1306 * @see java.lang.System#getProperty(java.lang.String, java.lang.String) 1307 */ 1308 public static Long getLong(String nm) { 1309 return getLong(nm, null); 1310 } 1311 1312 /** 1313 * Determines the {@code long} value of the system property 1314 * with the specified name. 1315 * 1316 * <p>The first argument is treated as the name of a system 1317 * property. System properties are accessible through the {@link 1318 * java.lang.System#getProperty(java.lang.String)} method. The 1319 * string value of this property is then interpreted as a {@code 1320 * long} value using the grammar supported by {@link Long#decode decode} 1321 * and a {@code Long} object representing this value is returned. 1322 * 1323 * <p>The second argument is the default value. A {@code Long} object 1324 * that represents the value of the second argument is returned if there 1325 * is no property of the specified name, if the property does not have 1326 * the correct numeric format, or if the specified name is empty or null. 1327 * 1328 * <p>In other words, this method returns a {@code Long} object equal 1329 * to the value of: 1330 * 1331 * <blockquote> 1332 * {@code getLong(nm, Long.valueOf(val))} 1333 * </blockquote> 1334 * 1335 * but in practice it may be implemented in a manner such as: 1336 * 1337 * <blockquote><pre> 1338 * Long result = getLong(nm, null); 1339 * return (result == null) ? Long.valueOf(val) : result; 1340 * </pre></blockquote> 1341 * 1342 * to avoid the unnecessary allocation of a {@code Long} object when 1343 * the default value is not needed. 1344 * 1345 * @param nm property name. 1346 * @param val default value. 1347 * @return the {@code Long} value of the property. 1348 * @throws SecurityException for the same reasons as 1349 * {@link System#getProperty(String) System.getProperty} 1350 * @see java.lang.System#getProperty(java.lang.String) 1351 * @see java.lang.System#getProperty(java.lang.String, java.lang.String) 1352 */ 1353 public static Long getLong(String nm, long val) { 1354 Long result = Long.getLong(nm, null); 1355 return (result == null) ? Long.valueOf(val) : result; 1356 } 1357 1358 /** 1359 * Returns the {@code long} value of the system property with 1360 * the specified name. The first argument is treated as the name 1361 * of a system property. System properties are accessible through 1362 * the {@link java.lang.System#getProperty(java.lang.String)} 1363 * method. The string value of this property is then interpreted 1364 * as a {@code long} value, as per the 1365 * {@link Long#decode decode} method, and a {@code Long} object 1366 * representing this value is returned; in summary: 1367 * 1368 * <ul> 1369 * <li>If the property value begins with the two ASCII characters 1370 * {@code 0x} or the ASCII character {@code #}, not followed by 1371 * a minus sign, then the rest of it is parsed as a hexadecimal integer 1372 * exactly as for the method {@link #valueOf(java.lang.String, int)} 1373 * with radix 16. 1374 * <li>If the property value begins with the ASCII character 1375 * {@code 0} followed by another character, it is parsed as 1376 * an octal integer exactly as by the method {@link 1377 * #valueOf(java.lang.String, int)} with radix 8. 1378 * <li>Otherwise the property value is parsed as a decimal 1379 * integer exactly as by the method 1380 * {@link #valueOf(java.lang.String, int)} with radix 10. 1381 * </ul> 1382 * 1383 * <p>Note that, in every case, neither {@code L} 1384 * ({@code '\u005Cu004C'}) nor {@code l} 1385 * ({@code '\u005Cu006C'}) is permitted to appear at the end 1386 * of the property value as a type indicator, as would be 1387 * permitted in Java programming language source code. 1388 * 1389 * <p>The second argument is the default value. The default value is 1390 * returned if there is no property of the specified name, if the 1391 * property does not have the correct numeric format, or if the 1392 * specified name is empty or {@code null}. 1393 * 1394 * @param nm property name. 1395 * @param val default value. 1396 * @return the {@code Long} value of the property. 1397 * @throws SecurityException for the same reasons as 1398 * {@link System#getProperty(String) System.getProperty} 1399 * @see System#getProperty(java.lang.String) 1400 * @see System#getProperty(java.lang.String, java.lang.String) 1401 */ 1402 public static Long getLong(String nm, Long val) { 1403 String v = null; 1404 try { 1405 v = System.getProperty(nm); 1406 } catch (IllegalArgumentException | NullPointerException e) { 1407 } 1408 if (v != null) { 1409 try { 1410 return Long.decode(v); 1411 } catch (NumberFormatException e) { 1412 } 1413 } 1414 return val; 1415 } 1416 1417 /** 1418 * Compares two {@code Long} objects numerically. 1419 * 1420 * @param anotherLong the {@code Long} to be compared. 1421 * @return the value {@code 0} if this {@code Long} is 1422 * equal to the argument {@code Long}; a value less than 1423 * {@code 0} if this {@code Long} is numerically less 1424 * than the argument {@code Long}; and a value greater 1425 * than {@code 0} if this {@code Long} is numerically 1426 * greater than the argument {@code Long} (signed 1427 * comparison). 1428 * @since 1.2 1429 */ 1430 public int compareTo(Long anotherLong) { 1431 return compare(this.value, anotherLong.value); 1432 } 1433 1434 /** 1435 * Compares two {@code long} values numerically. 1436 * The value returned is identical to what would be returned by: 1437 * <pre> 1438 * Long.valueOf(x).compareTo(Long.valueOf(y)) 1439 * </pre> 1440 * 1441 * @param x the first {@code long} to compare 1442 * @param y the second {@code long} to compare 1443 * @return the value {@code 0} if {@code x == y}; 1444 * a value less than {@code 0} if {@code x < y}; and 1445 * a value greater than {@code 0} if {@code x > y} 1446 * @since 1.7 1447 */ 1448 public static int compare(long x, long y) { 1449 return (x < y) ? -1 : ((x == y) ? 0 : 1); 1450 } 1451 1452 /** 1453 * Compares two {@code long} values numerically treating the values 1454 * as unsigned. 1455 * 1456 * @param x the first {@code long} to compare 1457 * @param y the second {@code long} to compare 1458 * @return the value {@code 0} if {@code x == y}; a value less 1459 * than {@code 0} if {@code x < y} as unsigned values; and 1460 * a value greater than {@code 0} if {@code x > y} as 1461 * unsigned values 1462 * @since 1.8 1463 */ 1464 @IntrinsicCandidate 1465 public static int compareUnsigned(long x, long y) { 1466 return compare(x + MIN_VALUE, y + MIN_VALUE); 1467 } 1468 1469 1470 /** 1471 * Returns the unsigned quotient of dividing the first argument by 1472 * the second where each argument and the result is interpreted as 1473 * an unsigned value. 1474 * 1475 * <p>Note that in two's complement arithmetic, the three other 1476 * basic arithmetic operations of add, subtract, and multiply are 1477 * bit-wise identical if the two operands are regarded as both 1478 * being signed or both being unsigned. Therefore separate {@code 1479 * addUnsigned}, etc. methods are not provided. 1480 * 1481 * @param dividend the value to be divided 1482 * @param divisor the value doing the dividing 1483 * @return the unsigned quotient of the first argument divided by 1484 * the second argument 1485 * @see #remainderUnsigned 1486 * @since 1.8 1487 */ 1488 @IntrinsicCandidate 1489 public static long divideUnsigned(long dividend, long divisor) { 1490 /* See Hacker's Delight (2nd ed), section 9.3 */ 1491 if (divisor >= 0) { 1492 final long q = (dividend >>> 1) / divisor << 1; 1493 final long r = dividend - q * divisor; 1494 return q + ((r | ~(r - divisor)) >>> (Long.SIZE - 1)); 1495 } 1496 return (dividend & ~(dividend - divisor)) >>> (Long.SIZE - 1); 1497 } 1498 1499 /** 1500 * Returns the unsigned remainder from dividing the first argument 1501 * by the second where each argument and the result is interpreted 1502 * as an unsigned value. 1503 * 1504 * @param dividend the value to be divided 1505 * @param divisor the value doing the dividing 1506 * @return the unsigned remainder of the first argument divided by 1507 * the second argument 1508 * @see #divideUnsigned 1509 * @since 1.8 1510 */ 1511 @IntrinsicCandidate 1512 public static long remainderUnsigned(long dividend, long divisor) { 1513 /* See Hacker's Delight (2nd ed), section 9.3 */ 1514 if (divisor >= 0) { 1515 final long q = (dividend >>> 1) / divisor << 1; 1516 final long r = dividend - q * divisor; 1517 /* 1518 * Here, 0 <= r < 2 * divisor 1519 * (1) When 0 <= r < divisor, the remainder is simply r. 1520 * (2) Otherwise the remainder is r - divisor. 1521 * 1522 * In case (1), r - divisor < 0. Applying ~ produces a long with 1523 * sign bit 0, so >> produces 0. The returned value is thus r. 1524 * 1525 * In case (2), a similar reasoning shows that >> produces -1, 1526 * so the returned value is r - divisor. 1527 */ 1528 return r - ((~(r - divisor) >> (Long.SIZE - 1)) & divisor); 1529 } 1530 /* 1531 * (1) When dividend >= 0, the remainder is dividend. 1532 * (2) Otherwise 1533 * (2.1) When dividend < divisor, the remainder is dividend. 1534 * (2.2) Otherwise the remainder is dividend - divisor 1535 * 1536 * A reasoning similar to the above shows that the returned value 1537 * is as expected. 1538 */ 1539 return dividend - (((dividend & ~(dividend - divisor)) >> (Long.SIZE - 1)) & divisor); 1540 } 1541 1542 // Bit Twiddling 1543 1544 /** 1545 * The number of bits used to represent a {@code long} value in two's 1546 * complement binary form. 1547 * 1548 * @since 1.5 1549 */ 1550 @Native public static final int SIZE = 64; 1551 1552 /** 1553 * The number of bytes used to represent a {@code long} value in two's 1554 * complement binary form. 1555 * 1556 * @since 1.8 1557 */ 1558 public static final int BYTES = SIZE / Byte.SIZE; 1559 1560 /** 1561 * Returns a {@code long} value with at most a single one-bit, in the 1562 * position of the highest-order ("leftmost") one-bit in the specified 1563 * {@code long} value. Returns zero if the specified value has no 1564 * one-bits in its two's complement binary representation, that is, if it 1565 * is equal to zero. 1566 * 1567 * @param i the value whose highest one bit is to be computed 1568 * @return a {@code long} value with a single one-bit, in the position 1569 * of the highest-order one-bit in the specified value, or zero if 1570 * the specified value is itself equal to zero. 1571 * @since 1.5 1572 */ 1573 public static long highestOneBit(long i) { 1574 return i & (MIN_VALUE >>> numberOfLeadingZeros(i)); 1575 } 1576 1577 /** 1578 * Returns a {@code long} value with at most a single one-bit, in the 1579 * position of the lowest-order ("rightmost") one-bit in the specified 1580 * {@code long} value. Returns zero if the specified value has no 1581 * one-bits in its two's complement binary representation, that is, if it 1582 * is equal to zero. 1583 * 1584 * @param i the value whose lowest one bit is to be computed 1585 * @return a {@code long} value with a single one-bit, in the position 1586 * of the lowest-order one-bit in the specified value, or zero if 1587 * the specified value is itself equal to zero. 1588 * @since 1.5 1589 */ 1590 public static long lowestOneBit(long i) { 1591 // HD, Section 2-1 1592 return i & -i; 1593 } 1594 1595 /** 1596 * Returns the number of zero bits preceding the highest-order 1597 * ("leftmost") one-bit in the two's complement binary representation 1598 * of the specified {@code long} value. Returns 64 if the 1599 * specified value has no one-bits in its two's complement representation, 1600 * in other words if it is equal to zero. 1601 * 1602 * <p>Note that this method is closely related to the logarithm base 2. 1603 * For all positive {@code long} values x: 1604 * <ul> 1605 * <li>floor(log<sub>2</sub>(x)) = {@code 63 - numberOfLeadingZeros(x)} 1606 * <li>ceil(log<sub>2</sub>(x)) = {@code 64 - numberOfLeadingZeros(x - 1)} 1607 * </ul> 1608 * 1609 * @param i the value whose number of leading zeros is to be computed 1610 * @return the number of zero bits preceding the highest-order 1611 * ("leftmost") one-bit in the two's complement binary representation 1612 * of the specified {@code long} value, or 64 if the value 1613 * is equal to zero. 1614 * @since 1.5 1615 */ 1616 @IntrinsicCandidate 1617 public static int numberOfLeadingZeros(long i) { 1618 int x = (int)(i >>> 32); 1619 return x == 0 ? 32 + Integer.numberOfLeadingZeros((int)i) 1620 : Integer.numberOfLeadingZeros(x); 1621 } 1622 1623 /** 1624 * Returns the number of zero bits following the lowest-order ("rightmost") 1625 * one-bit in the two's complement binary representation of the specified 1626 * {@code long} value. Returns 64 if the specified value has no 1627 * one-bits in its two's complement representation, in other words if it is 1628 * equal to zero. 1629 * 1630 * @param i the value whose number of trailing zeros is to be computed 1631 * @return the number of zero bits following the lowest-order ("rightmost") 1632 * one-bit in the two's complement binary representation of the 1633 * specified {@code long} value, or 64 if the value is equal 1634 * to zero. 1635 * @since 1.5 1636 */ 1637 @IntrinsicCandidate 1638 public static int numberOfTrailingZeros(long i) { 1639 int x = (int)i; 1640 return x == 0 ? 32 + Integer.numberOfTrailingZeros((int)(i >>> 32)) 1641 : Integer.numberOfTrailingZeros(x); 1642 } 1643 1644 /** 1645 * Returns the number of one-bits in the two's complement binary 1646 * representation of the specified {@code long} value. This function is 1647 * sometimes referred to as the <i>population count</i>. 1648 * 1649 * @param i the value whose bits are to be counted 1650 * @return the number of one-bits in the two's complement binary 1651 * representation of the specified {@code long} value. 1652 * @since 1.5 1653 */ 1654 @IntrinsicCandidate 1655 public static int bitCount(long i) { 1656 // HD, Figure 5-2 1657 i = i - ((i >>> 1) & 0x5555555555555555L); 1658 i = (i & 0x3333333333333333L) + ((i >>> 2) & 0x3333333333333333L); 1659 i = (i + (i >>> 4)) & 0x0f0f0f0f0f0f0f0fL; 1660 i = i + (i >>> 8); 1661 i = i + (i >>> 16); 1662 i = i + (i >>> 32); 1663 return (int)i & 0x7f; 1664 } 1665 1666 /** 1667 * Returns the value obtained by rotating the two's complement binary 1668 * representation of the specified {@code long} value left by the 1669 * specified number of bits. (Bits shifted out of the left hand, or 1670 * high-order, side reenter on the right, or low-order.) 1671 * 1672 * <p>Note that left rotation with a negative distance is equivalent to 1673 * right rotation: {@code rotateLeft(val, -distance) == rotateRight(val, 1674 * distance)}. Note also that rotation by any multiple of 64 is a 1675 * no-op, so all but the last six bits of the rotation distance can be 1676 * ignored, even if the distance is negative: {@code rotateLeft(val, 1677 * distance) == rotateLeft(val, distance & 0x3F)}. 1678 * 1679 * @param i the value whose bits are to be rotated left 1680 * @param distance the number of bit positions to rotate left 1681 * @return the value obtained by rotating the two's complement binary 1682 * representation of the specified {@code long} value left by the 1683 * specified number of bits. 1684 * @since 1.5 1685 */ 1686 public static long rotateLeft(long i, int distance) { 1687 return (i << distance) | (i >>> -distance); 1688 } 1689 1690 /** 1691 * Returns the value obtained by rotating the two's complement binary 1692 * representation of the specified {@code long} value right by the 1693 * specified number of bits. (Bits shifted out of the right hand, or 1694 * low-order, side reenter on the left, or high-order.) 1695 * 1696 * <p>Note that right rotation with a negative distance is equivalent to 1697 * left rotation: {@code rotateRight(val, -distance) == rotateLeft(val, 1698 * distance)}. Note also that rotation by any multiple of 64 is a 1699 * no-op, so all but the last six bits of the rotation distance can be 1700 * ignored, even if the distance is negative: {@code rotateRight(val, 1701 * distance) == rotateRight(val, distance & 0x3F)}. 1702 * 1703 * @param i the value whose bits are to be rotated right 1704 * @param distance the number of bit positions to rotate right 1705 * @return the value obtained by rotating the two's complement binary 1706 * representation of the specified {@code long} value right by the 1707 * specified number of bits. 1708 * @since 1.5 1709 */ 1710 public static long rotateRight(long i, int distance) { 1711 return (i >>> distance) | (i << -distance); 1712 } 1713 1714 /** 1715 * Returns the value obtained by reversing the order of the bits in the 1716 * two's complement binary representation of the specified {@code long} 1717 * value. 1718 * 1719 * @param i the value to be reversed 1720 * @return the value obtained by reversing order of the bits in the 1721 * specified {@code long} value. 1722 * @since 1.5 1723 */ 1724 @IntrinsicCandidate 1725 public static long reverse(long i) { 1726 // HD, Figure 7-1 1727 i = (i & 0x5555555555555555L) << 1 | (i >>> 1) & 0x5555555555555555L; 1728 i = (i & 0x3333333333333333L) << 2 | (i >>> 2) & 0x3333333333333333L; 1729 i = (i & 0x0f0f0f0f0f0f0f0fL) << 4 | (i >>> 4) & 0x0f0f0f0f0f0f0f0fL; 1730 1731 return reverseBytes(i); 1732 } 1733 1734 /** 1735 * Returns the value obtained by compressing the bits of the 1736 * specified {@code long} value, {@code i}, in accordance with 1737 * the specified bit mask. 1738 * <p> 1739 * For each one-bit value {@code mb} of the mask, from least 1740 * significant to most significant, the bit value of {@code i} at 1741 * the same bit location as {@code mb} is assigned to the compressed 1742 * value contiguously starting from the least significant bit location. 1743 * All the upper remaining bits of the compressed value are set 1744 * to zero. 1745 * 1746 * @apiNote 1747 * Consider the simple case of compressing the digits of a hexadecimal 1748 * value: 1749 * {@snippet lang="java" : 1750 * // Compressing drink to food 1751 * compress(0xCAFEBABEL, 0xFF00FFF0L) == 0xCABABL 1752 * } 1753 * Starting from the least significant hexadecimal digit at position 0 1754 * from the right, the mask {@code 0xFF00FFF0} selects hexadecimal digits 1755 * at positions 1, 2, 3, 6 and 7 of {@code 0xCAFEBABE}. The selected digits 1756 * occur in the resulting compressed value contiguously from digit position 1757 * 0 in the same order. 1758 * <p> 1759 * The following identities all return {@code true} and are helpful to 1760 * understand the behaviour of {@code compress}: 1761 * {@snippet lang="java" : 1762 * // Returns 1 if the bit at position n is one 1763 * compress(x, 1L << n) == (x >> n & 1) 1764 * 1765 * // Logical shift right 1766 * compress(x, -1L << n) == x >>> n 1767 * 1768 * // Any bits not covered by the mask are ignored 1769 * compress(x, m) == compress(x & m, m) 1770 * 1771 * // Compressing a value by itself 1772 * compress(m, m) == (m == -1 || m == 0) ? m : (1L << bitCount(m)) - 1 1773 * 1774 * // Expanding then compressing with the same mask 1775 * compress(expand(x, m), m) == x & compress(m, m) 1776 * } 1777 * <p> 1778 * The Sheep And Goats (SAG) operation (see Hacker's Delight, section 7.7) 1779 * can be implemented as follows: 1780 * {@snippet lang="java" : 1781 * long compressLeft(long i, long mask) { 1782 * // This implementation follows the description in Hacker's Delight which 1783 * // is informative. A more optimal implementation is: 1784 * // Long.compress(i, mask) << -Long.bitCount(mask) 1785 * return Long.reverse( 1786 * Long.compress(Long.reverse(i), Long.reverse(mask))); 1787 * } 1788 * 1789 * long sag(long i, long mask) { 1790 * return compressLeft(i, mask) | Long.compress(i, ~mask); 1791 * } 1792 * 1793 * // Separate the sheep from the goats 1794 * sag(0x00000000_CAFEBABEL, 0xFFFFFFFF_FF00FFF0L) == 0x00000000_CABABFEEL 1795 * } 1796 * 1797 * @param i the value whose bits are to be compressed 1798 * @param mask the bit mask 1799 * @return the compressed value 1800 * @see #expand 1801 * @since 19 1802 */ 1803 @IntrinsicCandidate 1804 public static long compress(long i, long mask) { 1805 // See Hacker's Delight (2nd ed) section 7.4 Compress, or Generalized Extract 1806 1807 i = i & mask; // Clear irrelevant bits 1808 long maskCount = ~mask << 1; // Count 0's to right 1809 1810 for (int j = 0; j < 6; j++) { 1811 // Parallel prefix 1812 // Mask prefix identifies bits of the mask that have an odd number of 0's to the right 1813 long maskPrefix = parallelSuffix(maskCount); 1814 // Bits to move 1815 long maskMove = maskPrefix & mask; 1816 // Compress mask 1817 mask = (mask ^ maskMove) | (maskMove >>> (1 << j)); 1818 // Bits of i to be moved 1819 long t = i & maskMove; 1820 // Compress i 1821 i = (i ^ t) | (t >>> (1 << j)); 1822 // Adjust the mask count by identifying bits that have 0 to the right 1823 maskCount = maskCount & ~maskPrefix; 1824 } 1825 return i; 1826 } 1827 1828 /** 1829 * Returns the value obtained by expanding the bits of the 1830 * specified {@code long} value, {@code i}, in accordance with 1831 * the specified bit mask. 1832 * <p> 1833 * For each one-bit value {@code mb} of the mask, from least 1834 * significant to most significant, the next contiguous bit value 1835 * of {@code i} starting at the least significant bit is assigned 1836 * to the expanded value at the same bit location as {@code mb}. 1837 * All other remaining bits of the expanded value are set to zero. 1838 * 1839 * @apiNote 1840 * Consider the simple case of expanding the digits of a hexadecimal 1841 * value: 1842 * {@snippet lang="java" : 1843 * expand(0x0000CABABL, 0xFF00FFF0L) == 0xCA00BAB0L 1844 * } 1845 * Starting from the least significant hexadecimal digit at position 0 1846 * from the right, the mask {@code 0xFF00FFF0} selects the first five 1847 * hexadecimal digits of {@code 0x0000CABAB}. The selected digits occur 1848 * in the resulting expanded value in order at positions 1, 2, 3, 6, and 7. 1849 * <p> 1850 * The following identities all return {@code true} and are helpful to 1851 * understand the behaviour of {@code expand}: 1852 * {@snippet lang="java" : 1853 * // Logically shift right the bit at position 0 1854 * expand(x, 1L << n) == (x & 1) << n 1855 * 1856 * // Logically shift right 1857 * expand(x, -1L << n) == x << n 1858 * 1859 * // Expanding all bits returns the mask 1860 * expand(-1L, m) == m 1861 * 1862 * // Any bits not covered by the mask are ignored 1863 * expand(x, m) == expand(x, m) & m 1864 * 1865 * // Compressing then expanding with the same mask 1866 * expand(compress(x, m), m) == x & m 1867 * } 1868 * <p> 1869 * The select operation for determining the position of the one-bit with 1870 * index {@code n} in a {@code long} value can be implemented as follows: 1871 * {@snippet lang="java" : 1872 * long select(long i, long n) { 1873 * // the one-bit in i (the mask) with index n 1874 * long nthBit = Long.expand(1L << n, i); 1875 * // the bit position of the one-bit with index n 1876 * return Long.numberOfTrailingZeros(nthBit); 1877 * } 1878 * 1879 * // The one-bit with index 0 is at bit position 1 1880 * select(0b10101010_10101010, 0) == 1 1881 * // The one-bit with index 3 is at bit position 7 1882 * select(0b10101010_10101010, 3) == 7 1883 * } 1884 * 1885 * @param i the value whose bits are to be expanded 1886 * @param mask the bit mask 1887 * @return the expanded value 1888 * @see #compress 1889 * @since 19 1890 */ 1891 @IntrinsicCandidate 1892 public static long expand(long i, long mask) { 1893 // Save original mask 1894 long originalMask = mask; 1895 // Count 0's to right 1896 long maskCount = ~mask << 1; 1897 long maskPrefix = parallelSuffix(maskCount); 1898 // Bits to move 1899 long maskMove1 = maskPrefix & mask; 1900 // Compress mask 1901 mask = (mask ^ maskMove1) | (maskMove1 >>> (1 << 0)); 1902 maskCount = maskCount & ~maskPrefix; 1903 1904 maskPrefix = parallelSuffix(maskCount); 1905 // Bits to move 1906 long maskMove2 = maskPrefix & mask; 1907 // Compress mask 1908 mask = (mask ^ maskMove2) | (maskMove2 >>> (1 << 1)); 1909 maskCount = maskCount & ~maskPrefix; 1910 1911 maskPrefix = parallelSuffix(maskCount); 1912 // Bits to move 1913 long maskMove3 = maskPrefix & mask; 1914 // Compress mask 1915 mask = (mask ^ maskMove3) | (maskMove3 >>> (1 << 2)); 1916 maskCount = maskCount & ~maskPrefix; 1917 1918 maskPrefix = parallelSuffix(maskCount); 1919 // Bits to move 1920 long maskMove4 = maskPrefix & mask; 1921 // Compress mask 1922 mask = (mask ^ maskMove4) | (maskMove4 >>> (1 << 3)); 1923 maskCount = maskCount & ~maskPrefix; 1924 1925 maskPrefix = parallelSuffix(maskCount); 1926 // Bits to move 1927 long maskMove5 = maskPrefix & mask; 1928 // Compress mask 1929 mask = (mask ^ maskMove5) | (maskMove5 >>> (1 << 4)); 1930 maskCount = maskCount & ~maskPrefix; 1931 1932 maskPrefix = parallelSuffix(maskCount); 1933 // Bits to move 1934 long maskMove6 = maskPrefix & mask; 1935 1936 long t = i << (1 << 5); 1937 i = (i & ~maskMove6) | (t & maskMove6); 1938 t = i << (1 << 4); 1939 i = (i & ~maskMove5) | (t & maskMove5); 1940 t = i << (1 << 3); 1941 i = (i & ~maskMove4) | (t & maskMove4); 1942 t = i << (1 << 2); 1943 i = (i & ~maskMove3) | (t & maskMove3); 1944 t = i << (1 << 1); 1945 i = (i & ~maskMove2) | (t & maskMove2); 1946 t = i << (1 << 0); 1947 i = (i & ~maskMove1) | (t & maskMove1); 1948 1949 // Clear irrelevant bits 1950 return i & originalMask; 1951 } 1952 1953 @ForceInline 1954 private static long parallelSuffix(long maskCount) { 1955 long maskPrefix = maskCount ^ (maskCount << 1); 1956 maskPrefix = maskPrefix ^ (maskPrefix << 2); 1957 maskPrefix = maskPrefix ^ (maskPrefix << 4); 1958 maskPrefix = maskPrefix ^ (maskPrefix << 8); 1959 maskPrefix = maskPrefix ^ (maskPrefix << 16); 1960 maskPrefix = maskPrefix ^ (maskPrefix << 32); 1961 return maskPrefix; 1962 } 1963 1964 /** 1965 * Returns the signum function of the specified {@code long} value. (The 1966 * return value is -1 if the specified value is negative; 0 if the 1967 * specified value is zero; and 1 if the specified value is positive.) 1968 * 1969 * @param i the value whose signum is to be computed 1970 * @return the signum function of the specified {@code long} value. 1971 * @since 1.5 1972 */ 1973 public static int signum(long i) { 1974 // HD, Section 2-7 1975 return (int) ((i >> 63) | (-i >>> 63)); 1976 } 1977 1978 /** 1979 * Returns the value obtained by reversing the order of the bytes in the 1980 * two's complement representation of the specified {@code long} value. 1981 * 1982 * @param i the value whose bytes are to be reversed 1983 * @return the value obtained by reversing the bytes in the specified 1984 * {@code long} value. 1985 * @since 1.5 1986 */ 1987 @IntrinsicCandidate 1988 public static long reverseBytes(long i) { 1989 i = (i & 0x00ff00ff00ff00ffL) << 8 | (i >>> 8) & 0x00ff00ff00ff00ffL; 1990 return (i << 48) | ((i & 0xffff0000L) << 16) | 1991 ((i >>> 16) & 0xffff0000L) | (i >>> 48); 1992 } 1993 1994 /** 1995 * Adds two {@code long} values together as per the + operator. 1996 * 1997 * @param a the first operand 1998 * @param b the second operand 1999 * @return the sum of {@code a} and {@code b} 2000 * @see java.util.function.BinaryOperator 2001 * @since 1.8 2002 */ 2003 public static long sum(long a, long b) { 2004 return a + b; 2005 } 2006 2007 /** 2008 * Returns the greater of two {@code long} values 2009 * as if by calling {@link Math#max(long, long) Math.max}. 2010 * 2011 * @param a the first operand 2012 * @param b the second operand 2013 * @return the greater of {@code a} and {@code b} 2014 * @see java.util.function.BinaryOperator 2015 * @since 1.8 2016 */ 2017 public static long max(long a, long b) { 2018 return Math.max(a, b); 2019 } 2020 2021 /** 2022 * Returns the smaller of two {@code long} values 2023 * as if by calling {@link Math#min(long, long) Math.min}. 2024 * 2025 * @param a the first operand 2026 * @param b the second operand 2027 * @return the smaller of {@code a} and {@code b} 2028 * @see java.util.function.BinaryOperator 2029 * @since 1.8 2030 */ 2031 public static long min(long a, long b) { 2032 return Math.min(a, b); 2033 } 2034 2035 /** 2036 * Returns an {@link Optional} containing the nominal descriptor for this 2037 * instance, which is the instance itself. 2038 * 2039 * @return an {@link Optional} describing the {@linkplain Long} instance 2040 * @since 12 2041 */ 2042 @Override 2043 public Optional<Long> describeConstable() { 2044 return Optional.of(this); 2045 } 2046 2047 /** 2048 * Resolves this instance as a {@link ConstantDesc}, the result of which is 2049 * the instance itself. 2050 * 2051 * @param lookup ignored 2052 * @return the {@linkplain Long} instance 2053 * @since 12 2054 */ 2055 @Override 2056 public Long resolveConstantDesc(MethodHandles.Lookup lookup) { 2057 return this; 2058 } 2059 2060 /** use serialVersionUID from JDK 1.0.2 for interoperability */ 2061 @java.io.Serial 2062 @Native private static final long serialVersionUID = 4290774380558885855L; 2063 }