1 /*
2 * Copyright (c) 1994, 2026, 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.misc.PreviewFeatures;
38 import jdk.internal.value.DeserializeConstructor;
39 import jdk.internal.util.DecimalDigits;
40 import jdk.internal.vm.annotation.AOTSafeClassInitializer;
41 import jdk.internal.vm.annotation.ForceInline;
42 import jdk.internal.vm.annotation.IntrinsicCandidate;
43 import jdk.internal.vm.annotation.Stable;
44
45 import static java.lang.Character.digit;
46 import static java.lang.String.COMPACT_STRINGS;
47
48 /**
49 * The {@code Long} class is the {@linkplain
50 * java.lang##wrapperClass wrapper class} for values of the primitive
51 * type {@code long}. An object of type {@code Long} contains a
52 * single field whose type is {@code long}.
53 *
54 * <p> In addition, this class provides several methods for converting
55 * a {@code long} to a {@code String} and a {@code String} to a {@code
56 * long}, as well as other constants and methods useful when dealing
57 * with a {@code long}.
58 *
59 * <p>This is a <a href="{@docRoot}/java.base/java/lang/doc-files/ValueBased.html">value-based</a>
60 * class; programmers should treat instances that are {@linkplain #equals(Object) equal}
61 * as interchangeable and should not use instances for synchronization, mutexes, or
62 * with {@linkplain java.lang.ref.Reference object references}.
63 *
64 * <div class="preview-block">
65 * <div class="preview-comment">
66 * When preview features are enabled, {@code Long} is a {@linkplain Class#isValue value class}.
67 * Use of value class instances for synchronization, mutexes, or with
68 * {@linkplain java.lang.ref.Reference object references} result in
69 * {@link IdentityException}.
70 * </div>
71 * </div>
72 *
73 *
74 * <p>Implementation note: The implementations of the "bit twiddling"
75 * methods (such as {@link #highestOneBit(long) highestOneBit} and
76 * {@link #numberOfTrailingZeros(long) numberOfTrailingZeros}) are
77 * based on material from Henry S. Warren, Jr.'s <cite>Hacker's
78 * Delight</cite>, (Addison Wesley, 2002) and <cite>Hacker's
79 * Delight, Second Edition</cite>, (Pearson Education, 2013).
80 *
81 * @since 1.0
82 */
83 @jdk.internal.MigratedValueClass
84 @jdk.internal.ValueBased
85 public final class Long extends Number
86 implements Comparable<Long>, Constable, ConstantDesc {
87 /**
88 * A constant holding the minimum value a {@code long} can
89 * have, -2<sup>63</sup>.
90 */
91 @Native public static final long MIN_VALUE = 0x8000000000000000L;
92
93 /**
94 * A constant holding the maximum value a {@code long} can
95 * have, 2<sup>63</sup>-1.
96 */
97 @Native public static final long MAX_VALUE = 0x7fffffffffffffffL;
98
99 /**
100 * The {@code Class} instance representing the primitive type
101 * {@code long}.
102 *
103 * @since 1.1
104 */
105 public static final Class<Long> TYPE = Class.getPrimitiveClass("long");
106
107 /**
108 * Returns a string representation of the first argument in the
109 * radix specified by the second argument.
110 *
111 * <p>If the radix is smaller than {@code Character.MIN_RADIX}
112 * or larger than {@code Character.MAX_RADIX}, then the radix
113 * {@code 10} is used instead.
114 *
115 * <p>If the first argument is negative, the first element of the
116 * result is the ASCII minus sign {@code '-'}
117 * ({@code '\u005Cu002d'}). If the first argument is not
118 * negative, no sign character appears in the result.
119 *
120 * <p>The remaining characters of the result represent the magnitude
121 * of the first argument. If the magnitude is zero, it is
122 * represented by a single zero character {@code '0'}
123 * ({@code '\u005Cu0030'}); otherwise, the first character of
124 * the representation of the magnitude will not be the zero
125 * character. The following ASCII characters are used as digits:
126 *
127 * <blockquote>
128 * {@code 0123456789abcdefghijklmnopqrstuvwxyz}
129 * </blockquote>
130 *
131 * These are {@code '\u005Cu0030'} through
132 * {@code '\u005Cu0039'} and {@code '\u005Cu0061'} through
133 * {@code '\u005Cu007a'}. If {@code radix} is
134 * <var>N</var>, then the first <var>N</var> of these characters
135 * are used as radix-<var>N</var> digits in the order shown. Thus,
136 * the digits for hexadecimal (radix 16) are
137 * {@code 0123456789abcdef}. If uppercase letters are
138 * desired, the {@link java.lang.String#toUpperCase()} method may
139 * be called on the result:
140 *
141 * <blockquote>
142 * {@code Long.toString(n, 16).toUpperCase()}
143 * </blockquote>
144 *
145 * @param i a {@code long} to be converted to a string.
146 * @param radix the radix to use in the string representation.
147 * @return a string representation of the argument in the specified radix.
148 * @see java.lang.Character#MAX_RADIX
149 * @see java.lang.Character#MIN_RADIX
150 */
151 public static String toString(long i, int radix) {
152 if (radix < Character.MIN_RADIX || radix > Character.MAX_RADIX)
153 radix = 10;
154 if (radix == 10)
155 return toString(i);
156
157 if (COMPACT_STRINGS) {
158 byte[] buf = new byte[65];
159 int charPos = 64;
160 boolean negative = (i < 0);
161
162 if (!negative) {
163 i = -i;
164 }
165
166 while (i <= -radix) {
167 buf[charPos--] = Integer.digits[(int)(-(i % radix))];
168 i = i / radix;
169 }
170 buf[charPos] = Integer.digits[(int)(-i)];
171
172 if (negative) {
173 buf[--charPos] = '-';
174 }
175 return StringLatin1.newString(buf, charPos, (65 - charPos));
176 }
177 return toStringUTF16(i, radix);
178 }
179
180 private static String toStringUTF16(long i, int radix) {
181 byte[] buf = new byte[65 * 2];
182 int charPos = 64;
183 boolean negative = (i < 0);
184 if (!negative) {
185 i = -i;
186 }
187 while (i <= -radix) {
188 StringUTF16.putChar(buf, charPos--, Integer.digits[(int)(-(i % radix))]);
189 i = i / radix;
190 }
191 StringUTF16.putChar(buf, charPos, Integer.digits[(int)(-i)]);
192 if (negative) {
193 StringUTF16.putChar(buf, --charPos, '-');
194 }
195 return StringUTF16.newString(buf, charPos, (65 - charPos));
196 }
197
198 /**
199 * Returns a string representation of the first argument as an
200 * unsigned integer value in the radix specified by the second
201 * argument.
202 *
203 * <p>If the radix is smaller than {@code Character.MIN_RADIX}
204 * or larger than {@code Character.MAX_RADIX}, then the radix
205 * {@code 10} is used instead.
206 *
207 * <p>Note that since the first argument is treated as an unsigned
208 * value, no leading sign character is printed.
209 *
210 * <p>If the magnitude is zero, it is represented by a single zero
211 * character {@code '0'} ({@code '\u005Cu0030'}); otherwise,
212 * the first character of the representation of the magnitude will
213 * not be the zero character.
214 *
215 * <p>The behavior of radixes and the characters used as digits
216 * are the same as {@link #toString(long, int) toString}.
217 *
218 * @param i an integer to be converted to an unsigned string.
219 * @param radix the radix to use in the string representation.
220 * @return an unsigned string representation of the argument in the specified radix.
221 * @see #toString(long, int)
222 * @since 1.8
223 */
224 public static String toUnsignedString(long i, int radix) {
225 if (i >= 0)
226 return toString(i, radix);
227 else {
228 return switch (radix) {
229 case 2 -> toBinaryString(i);
230 case 4 -> toUnsignedString0(i, 2);
231 case 8 -> toOctalString(i);
232 case 10 -> {
233 /*
234 * We can get the effect of an unsigned division by 10
235 * on a long value by first shifting right, yielding a
236 * positive value, and then dividing by 5. This
237 * allows the last digit and preceding digits to be
238 * isolated more quickly than by an initial conversion
239 * to BigInteger.
240 */
241 long quot = (i >>> 1) / 5;
242 long rem = i - quot * 10;
243 yield toString(quot) + rem;
244 }
245 case 16 -> toHexString(i);
246 case 32 -> toUnsignedString0(i, 5);
247 default -> toUnsignedBigInteger(i).toString(radix);
248 };
249 }
250 }
251
252 /**
253 * Return a BigInteger equal to the unsigned value of the
254 * argument.
255 */
256 private static BigInteger toUnsignedBigInteger(long i) {
257 if (i >= 0L)
258 return BigInteger.valueOf(i);
259 else {
260 int upper = (int) (i >>> 32);
261 int lower = (int) i;
262
263 // return (upper << 32) + lower
264 return (BigInteger.valueOf(Integer.toUnsignedLong(upper))).shiftLeft(32).
265 add(BigInteger.valueOf(Integer.toUnsignedLong(lower)));
266 }
267 }
268
269 /**
270 * Returns a string representation of the {@code long}
271 * argument as an unsigned integer in base 16.
272 *
273 * <p>The unsigned {@code long} value is the argument plus
274 * 2<sup>64</sup> if the argument is negative; otherwise, it is
275 * equal to the argument. This value is converted to a string of
276 * ASCII digits in hexadecimal (base 16) with no extra
277 * leading {@code 0}s.
278 *
279 * <p>The value of the argument can be recovered from the returned
280 * string {@code s} by calling {@link
281 * Long#parseUnsignedLong(String, int) Long.parseUnsignedLong(s,
282 * 16)}.
283 *
284 * <p>If the unsigned magnitude is zero, it is represented by a
285 * single zero character {@code '0'} ({@code '\u005Cu0030'});
286 * otherwise, the first character of the representation of the
287 * unsigned magnitude will not be the zero character. The
288 * following characters are used as hexadecimal digits:
289 *
290 * <blockquote>
291 * {@code 0123456789abcdef}
292 * </blockquote>
293 *
294 * These are the characters {@code '\u005Cu0030'} through
295 * {@code '\u005Cu0039'} and {@code '\u005Cu0061'} through
296 * {@code '\u005Cu0066'}. If uppercase letters are desired,
297 * the {@link java.lang.String#toUpperCase()} method may be called
298 * on the result:
299 *
300 * <blockquote>
301 * {@code Long.toHexString(n).toUpperCase()}
302 * </blockquote>
303 *
304 * @apiNote
305 * The {@link java.util.HexFormat} class provides formatting and parsing
306 * of byte arrays and primitives to return a string or adding to an {@link Appendable}.
307 * {@code HexFormat} formats and parses uppercase or lowercase hexadecimal characters,
308 * with leading zeros and for byte arrays includes for each byte
309 * a delimiter, prefix, and suffix.
310 *
311 * @param i a {@code long} to be converted to a string.
312 * @return the string representation of the unsigned {@code long}
313 * value represented by the argument in hexadecimal
314 * (base 16).
315 * @see java.util.HexFormat
316 * @see #parseUnsignedLong(String, int)
317 * @see #toUnsignedString(long, int)
318 * @since 1.0.2
319 */
320 public static String toHexString(long i) {
321 return toUnsignedString0(i, 4);
322 }
323
324 /**
325 * Returns a string representation of the {@code long}
326 * argument as an unsigned integer in base 8.
327 *
328 * <p>The unsigned {@code long} value is the argument plus
329 * 2<sup>64</sup> if the argument is negative; otherwise, it is
330 * equal to the argument. This value is converted to a string of
331 * ASCII digits in octal (base 8) with no extra leading
332 * {@code 0}s.
333 *
334 * <p>The value of the argument can be recovered from the returned
335 * string {@code s} by calling {@link
336 * Long#parseUnsignedLong(String, int) Long.parseUnsignedLong(s,
337 * 8)}.
338 *
339 * <p>If the unsigned magnitude is zero, it is represented by a
340 * single zero character {@code '0'} ({@code '\u005Cu0030'});
341 * otherwise, the first character of the representation of the
342 * unsigned magnitude will not be the zero character. The
343 * following characters are used as octal digits:
344 *
345 * <blockquote>
346 * {@code 01234567}
347 * </blockquote>
348 *
349 * These are the characters {@code '\u005Cu0030'} through
350 * {@code '\u005Cu0037'}.
351 *
352 * @param i a {@code long} to be converted to a string.
353 * @return the string representation of the unsigned {@code long}
354 * value represented by the argument in octal (base 8).
355 * @see #parseUnsignedLong(String, int)
356 * @see #toUnsignedString(long, int)
357 * @since 1.0.2
358 */
359 public static String toOctalString(long i) {
360 return toUnsignedString0(i, 3);
361 }
362
363 /**
364 * Returns a string representation of the {@code long}
365 * argument as an unsigned integer in base 2.
366 *
367 * <p>The unsigned {@code long} value is the argument plus
368 * 2<sup>64</sup> if the argument is negative; otherwise, it is
369 * equal to the argument. This value is converted to a string of
370 * ASCII digits in binary (base 2) with no extra leading
371 * {@code 0}s.
372 *
373 * <p>The value of the argument can be recovered from the returned
374 * string {@code s} by calling {@link
375 * Long#parseUnsignedLong(String, int) Long.parseUnsignedLong(s,
376 * 2)}.
377 *
378 * <p>If the unsigned magnitude is zero, it is represented by a
379 * single zero character {@code '0'} ({@code '\u005Cu0030'});
380 * otherwise, the first character of the representation of the
381 * unsigned magnitude will not be the zero character. The
382 * characters {@code '0'} ({@code '\u005Cu0030'}) and {@code
383 * '1'} ({@code '\u005Cu0031'}) are used as binary digits.
384 *
385 * @param i a {@code long} to be converted to a string.
386 * @return the string representation of the unsigned {@code long}
387 * value represented by the argument in binary (base 2).
388 * @see #parseUnsignedLong(String, int)
389 * @see #toUnsignedString(long, int)
390 * @since 1.0.2
391 */
392 public static String toBinaryString(long i) {
393 return toUnsignedString0(i, 1);
394 }
395
396 /**
397 * Format a long (treated as unsigned) into a String.
398 * @param val the value to format
399 * @param shift the log2 of the base to format in (4 for hex, 3 for octal, 1 for binary)
400 */
401 static String toUnsignedString0(long val, int shift) {
402 // assert shift > 0 && shift <=5 : "Illegal shift value";
403 int mag = Long.SIZE - Long.numberOfLeadingZeros(val);
404 int chars = Math.max(((mag + (shift - 1)) / shift), 1);
405 byte[] buf = new byte[chars];
406 formatUnsignedLong0(val, shift, buf, 0, chars);
407 return String.newStringWithLatin1Bytes(buf);
408 }
409
410 /**
411 * Format a long (treated as unsigned) into a byte buffer (LATIN1 version). If
412 * {@code len} exceeds the formatted ASCII representation of {@code val},
413 * {@code buf} will be padded with leading zeroes.
414 *
415 * @param val the unsigned long to format
416 * @param shift the log2 of the base to format in (4 for hex, 3 for octal, 1 for binary)
417 * @param buf the byte buffer to write to
418 * @param offset the offset in the destination buffer to start at
419 * @param len the number of characters to write
420 */
421 private static void formatUnsignedLong0(long val, int shift, byte[] buf, int offset, int len) {
422 int charPos = offset + len;
423 int radix = 1 << shift;
424 int mask = radix - 1;
425 do {
426 buf[--charPos] = Integer.digits[((int) val) & mask];
427 val >>>= shift;
428 } while (charPos > offset);
429 }
430
431 /**
432 * Returns a {@code String} object representing the specified
433 * {@code long}. The argument is converted to signed decimal
434 * representation and returned as a string, exactly as if the
435 * argument and the radix 10 were given as arguments to the {@link
436 * #toString(long, int)} method.
437 *
438 * @param i a {@code long} to be converted.
439 * @return a string representation of the argument in base 10.
440 */
441 public static String toString(long i) {
442 int size = DecimalDigits.stringSize(i);
443 byte[] buf = new byte[size];
444 DecimalDigits.uncheckedGetCharsLatin1(i, size, buf);
445 return String.newStringWithLatin1Bytes(buf);
446 }
447
448 /**
449 * Returns a string representation of the argument as an unsigned
450 * decimal value.
451 *
452 * The argument is converted to unsigned decimal representation
453 * and returned as a string exactly as if the argument and radix
454 * 10 were given as arguments to the {@link #toUnsignedString(long,
455 * int)} method.
456 *
457 * @param i an integer to be converted to an unsigned string.
458 * @return an unsigned string representation of the argument.
459 * @see #toUnsignedString(long, int)
460 * @since 1.8
461 */
462 public static String toUnsignedString(long i) {
463 return toUnsignedString(i, 10);
464 }
465
466 /**
467 * Parses the string argument as a signed {@code long} in the
468 * radix specified by the second argument. The characters in the
469 * string must all be digits of the specified radix (as determined
470 * by whether {@link java.lang.Character#digit(char, int)} returns
471 * a nonnegative value), except that the first character may be an
472 * ASCII minus sign {@code '-'} ({@code '\u005Cu002D'}) to
473 * indicate a negative value or an ASCII plus sign {@code '+'}
474 * ({@code '\u005Cu002B'}) to indicate a positive value. The
475 * resulting {@code long} value is returned.
476 *
477 * <p>Note that neither the character {@code L}
478 * ({@code '\u005Cu004C'}) nor {@code l}
479 * ({@code '\u005Cu006C'}) is permitted to appear at the end
480 * of the string as a type indicator, as would be permitted in
481 * Java programming language source code - except that either
482 * {@code L} or {@code l} may appear as a digit for a
483 * radix greater than or equal to 22.
484 *
485 * <p>An exception of type {@code NumberFormatException} is
486 * thrown if any of the following situations occurs:
487 * <ul>
488 *
489 * <li>The first argument is {@code null} or is a string of
490 * length zero.
491 *
492 * <li>The {@code radix} is either smaller than {@link
493 * java.lang.Character#MIN_RADIX} or larger than {@link
494 * java.lang.Character#MAX_RADIX}.
495 *
496 * <li>Any character of the string is not a digit of the specified
497 * radix, except that the first character may be a minus sign
498 * {@code '-'} ({@code '\u005Cu002d'}) or plus sign {@code
499 * '+'} ({@code '\u005Cu002B'}) provided that the string is
500 * longer than length 1.
501 *
502 * <li>The value represented by the string is not a value of type
503 * {@code long}.
504 * </ul>
505 *
506 * <p>Examples:
507 * <blockquote><pre>
508 * parseLong("0", 10) returns 0L
509 * parseLong("473", 10) returns 473L
510 * parseLong("+42", 10) returns 42L
511 * parseLong("-0", 10) returns 0L
512 * parseLong("-FF", 16) returns -255L
513 * parseLong("1100110", 2) returns 102L
514 * parseLong("99", 8) throws a NumberFormatException
515 * parseLong("Hazelnut", 10) throws a NumberFormatException
516 * parseLong("Hazelnut", 36) returns 1356099454469L
517 * </pre></blockquote>
518 *
519 * @param s the {@code String} containing the
520 * {@code long} representation to be parsed.
521 * @param radix the radix to be used while parsing {@code s}.
522 * @return the {@code long} represented by the string argument in
523 * the specified radix.
524 * @throws NumberFormatException if the string does not contain a
525 * parsable {@code long}.
526 */
527 public static long parseLong(String s, int radix)
528 throws NumberFormatException {
529 if (s == null) {
530 throw new NumberFormatException("Cannot parse null string");
531 }
532
533 if (radix < Character.MIN_RADIX) {
534 throw new NumberFormatException(String.format(
535 "radix %s less than Character.MIN_RADIX", radix));
536 }
537
538 if (radix > Character.MAX_RADIX) {
539 throw new NumberFormatException(String.format(
540 "radix %s greater than Character.MAX_RADIX", radix));
541 }
542
543 int len = s.length();
544 if (len == 0) {
545 throw NumberFormatException.forInputString("", radix);
546 }
547 int digit = ~0xFF;
548 int i = 0;
549 char firstChar = s.charAt(i++);
550 if (firstChar != '-' && firstChar != '+') {
551 digit = digit(firstChar, radix);
552 }
553 if (digit >= 0 || digit == ~0xFF && len > 1) {
554 long limit = firstChar != '-' ? MIN_VALUE + 1 : MIN_VALUE;
555 long multmin = limit / radix;
556 long result = -(digit & 0xFF);
557 boolean inRange = true;
558 /* Accumulating negatively avoids surprises near MAX_VALUE */
559 while (i < len && (digit = digit(s.charAt(i++), radix)) >= 0
560 && (inRange = result > multmin
561 || result == multmin && digit <= (int) (radix * multmin - limit))) {
562 result = radix * result - digit;
563 }
564 if (inRange && i == len && digit >= 0) {
565 return firstChar != '-' ? -result : result;
566 }
567 }
568 throw NumberFormatException.forInputString(s, radix);
569 }
570
571 /**
572 * Parses the {@link CharSequence} argument as a signed {@code long} in
573 * the specified {@code radix}, beginning at the specified
574 * {@code beginIndex} and extending to {@code endIndex - 1}.
575 *
576 * <p>The method does not take steps to guard against the
577 * {@code CharSequence} being mutated while parsing.
578 *
579 * @param s the {@code CharSequence} containing the {@code long}
580 * representation to be parsed
581 * @param beginIndex the beginning index, inclusive.
582 * @param endIndex the ending index, exclusive.
583 * @param radix the radix to be used while parsing {@code s}.
584 * @return the signed {@code long} represented by the subsequence in
585 * the specified radix.
586 * @throws NullPointerException if {@code s} is null.
587 * @throws IndexOutOfBoundsException if {@code beginIndex} is
588 * negative, or if {@code beginIndex} is greater than
589 * {@code endIndex} or if {@code endIndex} is greater than
590 * {@code s.length()}.
591 * @throws NumberFormatException if the {@code CharSequence} does not
592 * contain a parsable {@code long} in the specified
593 * {@code radix}, or if {@code radix} is either smaller than
594 * {@link java.lang.Character#MIN_RADIX} or larger than
595 * {@link java.lang.Character#MAX_RADIX}.
596 * @since 9
597 */
598 public static long parseLong(CharSequence s, int beginIndex, int endIndex, int radix)
599 throws NumberFormatException {
600 Objects.requireNonNull(s);
601 Objects.checkFromToIndex(beginIndex, endIndex, s.length());
602
603 if (radix < Character.MIN_RADIX) {
604 throw new NumberFormatException(String.format(
605 "radix %s less than Character.MIN_RADIX", radix));
606 }
607
608 if (radix > Character.MAX_RADIX) {
609 throw new NumberFormatException(String.format(
610 "radix %s greater than Character.MAX_RADIX", radix));
611 }
612
613 /*
614 * While s can be concurrently modified, it is ensured that each
615 * of its characters is read at most once, from lower to higher indices.
616 * This is obtained by reading them using the pattern s.charAt(i++),
617 * and by not updating i anywhere else.
618 */
619 if (beginIndex == endIndex) {
620 throw NumberFormatException.forInputString("", radix);
621 }
622 int digit = ~0xFF; // ~0xFF means firstChar char is sign
623 int i = beginIndex;
624 char firstChar = s.charAt(i++);
625 if (firstChar != '-' && firstChar != '+') {
626 digit = digit(firstChar, radix);
627 }
628 if (digit >= 0 || digit == ~0xFF && endIndex - beginIndex > 1) {
629 long limit = firstChar != '-' ? MIN_VALUE + 1 : MIN_VALUE;
630 long multmin = limit / radix;
631 long result = -(digit & 0xFF);
632 boolean inRange = true;
633 /* Accumulating negatively avoids surprises near MAX_VALUE */
634 while (i < endIndex && (digit = digit(s.charAt(i++), radix)) >= 0
635 && (inRange = result > multmin
636 || result == multmin && digit <= (int) (radix * multmin - limit))) {
637 result = radix * result - digit;
638 }
639 if (inRange && i == endIndex && digit >= 0) {
640 return firstChar != '-' ? -result : result;
641 }
642 }
643 throw NumberFormatException.forCharSequence(s, beginIndex,
644 endIndex, i - (digit < -1 ? 0 : 1));
645 }
646
647 /**
648 * Parses the string argument as a signed decimal {@code long}.
649 * The characters in the string must all be decimal digits, except
650 * that the first character may be an ASCII minus sign {@code '-'}
651 * ({@code \u005Cu002D'}) to indicate a negative value or an
652 * ASCII plus sign {@code '+'} ({@code '\u005Cu002B'}) to
653 * indicate a positive value. The resulting {@code long} value is
654 * returned, exactly as if the argument and the radix {@code 10}
655 * were given as arguments to the {@link
656 * #parseLong(java.lang.String, int)} method.
657 *
658 * <p>Note that neither the character {@code L}
659 * ({@code '\u005Cu004C'}) nor {@code l}
660 * ({@code '\u005Cu006C'}) is permitted to appear at the end
661 * of the string as a type indicator, as would be permitted in
662 * Java programming language source code.
663 *
664 * @param s a {@code String} containing the {@code long}
665 * representation to be parsed
666 * @return the {@code long} represented by the argument in
667 * decimal.
668 * @throws NumberFormatException if the string does not contain a
669 * parsable {@code long}.
670 */
671 public static long parseLong(String s) throws NumberFormatException {
672 return parseLong(s, 10);
673 }
674
675 /**
676 * Parses the string argument as an unsigned {@code long} in the
677 * radix specified by the second argument. An unsigned integer
678 * maps the values usually associated with negative numbers to
679 * positive numbers larger than {@code MAX_VALUE}.
680 *
681 * The characters in the string must all be digits of the
682 * specified radix (as determined by whether {@link
683 * java.lang.Character#digit(char, int)} returns a nonnegative
684 * value), except that the first character may be an ASCII plus
685 * sign {@code '+'} ({@code '\u005Cu002B'}). The resulting
686 * integer value is returned.
687 *
688 * <p>An exception of type {@code NumberFormatException} is
689 * thrown if any of the following situations occurs:
690 * <ul>
691 * <li>The first argument is {@code null} or is a string of
692 * length zero.
693 *
694 * <li>The radix is either smaller than
695 * {@link java.lang.Character#MIN_RADIX} or
696 * larger than {@link java.lang.Character#MAX_RADIX}.
697 *
698 * <li>Any character of the string is not a digit of the specified
699 * radix, except that the first character may be a plus sign
700 * {@code '+'} ({@code '\u005Cu002B'}) provided that the
701 * string is longer than length 1.
702 *
703 * <li>The value represented by the string is larger than the
704 * largest unsigned {@code long}, 2<sup>64</sup>-1.
705 *
706 * </ul>
707 *
708 *
709 * @param s the {@code String} containing the unsigned integer
710 * representation to be parsed
711 * @param radix the radix to be used while parsing {@code s}.
712 * @return the unsigned {@code long} represented by the string
713 * argument in the specified radix.
714 * @throws NumberFormatException if the {@code String}
715 * does not contain a parsable {@code long}.
716 * @since 1.8
717 */
718 public static long parseUnsignedLong(String s, int radix)
719 throws NumberFormatException {
720 if (s == null) {
721 throw new NumberFormatException("Cannot parse null string");
722 }
723
724 if (radix < Character.MIN_RADIX) {
725 throw new NumberFormatException(String.format(
726 "radix %s less than Character.MIN_RADIX", radix));
727 }
728
729 if (radix > Character.MAX_RADIX) {
730 throw new NumberFormatException(String.format(
731 "radix %s greater than Character.MAX_RADIX", radix));
732 }
733
734 int len = s.length();
735 if (len == 0) {
736 throw NumberFormatException.forInputString(s, radix);
737 }
738 int i = 0;
739 char firstChar = s.charAt(i++);
740 if (firstChar == '-') {
741 throw new NumberFormatException(String.format(
742 "Illegal leading minus sign on unsigned string %s.", s));
743 }
744 int digit = ~0xFF;
745 if (firstChar != '+') {
746 digit = digit(firstChar, radix);
747 }
748 if (digit >= 0 || digit == ~0xFF && len > 1) {
749 long multmax = divideUnsigned(-1L, radix); // -1L is max unsigned long
750 long result = digit & 0xFF;
751 boolean inRange = true;
752 while (i < len && (digit = digit(s.charAt(i++), radix)) >= 0
753 && (inRange = compareUnsigned(result, multmax) < 0
754 || result == multmax && digit < (int) (-radix * multmax))) {
755 result = radix * result + digit;
756 }
757 if (inRange && i == len && digit >= 0) {
758 return result;
759 }
760 }
761 if (digit < 0) {
762 throw NumberFormatException.forInputString(s, radix);
763 }
764 throw new NumberFormatException(String.format(
765 "String value %s exceeds range of unsigned long.", s));
766 }
767
768 /**
769 * Parses the {@link CharSequence} argument as an unsigned {@code long} in
770 * the specified {@code radix}, beginning at the specified
771 * {@code beginIndex} and extending to {@code endIndex - 1}.
772 *
773 * <p>The method does not take steps to guard against the
774 * {@code CharSequence} being mutated while parsing.
775 *
776 * @param s the {@code CharSequence} containing the unsigned
777 * {@code long} representation to be parsed
778 * @param beginIndex the beginning index, inclusive.
779 * @param endIndex the ending index, exclusive.
780 * @param radix the radix to be used while parsing {@code s}.
781 * @return the unsigned {@code long} represented by the subsequence in
782 * the specified radix.
783 * @throws NullPointerException if {@code s} is null.
784 * @throws IndexOutOfBoundsException if {@code beginIndex} is
785 * negative, or if {@code beginIndex} is greater than
786 * {@code endIndex} or if {@code endIndex} is greater than
787 * {@code s.length()}.
788 * @throws NumberFormatException if the {@code CharSequence} does not
789 * contain a parsable unsigned {@code long} in the specified
790 * {@code radix}, or if {@code radix} is either smaller than
791 * {@link java.lang.Character#MIN_RADIX} or larger than
792 * {@link java.lang.Character#MAX_RADIX}.
793 * @since 9
794 */
795 public static long parseUnsignedLong(CharSequence s, int beginIndex, int endIndex, int radix)
796 throws NumberFormatException {
797 Objects.requireNonNull(s);
798 Objects.checkFromToIndex(beginIndex, endIndex, s.length());
799
800 if (radix < Character.MIN_RADIX) {
801 throw new NumberFormatException(String.format(
802 "radix %s less than Character.MIN_RADIX", radix));
803 }
804
805 if (radix > Character.MAX_RADIX) {
806 throw new NumberFormatException(String.format(
807 "radix %s greater than Character.MAX_RADIX", radix));
808 }
809
810 /*
811 * While s can be concurrently modified, it is ensured that each
812 * of its characters is read at most once, from lower to higher indices.
813 * This is obtained by reading them using the pattern s.charAt(i++),
814 * and by not updating i anywhere else.
815 */
816 if (beginIndex == endIndex) {
817 throw NumberFormatException.forInputString("", radix);
818 }
819 int i = beginIndex;
820 char firstChar = s.charAt(i++);
821 if (firstChar == '-') {
822 throw new NumberFormatException(
823 "Illegal leading minus sign on unsigned string " + s + ".");
824 }
825 int digit = ~0xFF;
826 if (firstChar != '+') {
827 digit = digit(firstChar, radix);
828 }
829 if (digit >= 0 || digit == ~0xFF && endIndex - beginIndex > 1) {
830 long multmax = divideUnsigned(-1L, radix); // -1L is max unsigned long
831 long result = digit & 0xFF;
832 boolean inRange = true;
833 while (i < endIndex && (digit = digit(s.charAt(i++), radix)) >= 0
834 && (inRange = compareUnsigned(result, multmax) < 0
835 || result == multmax && digit < (int) (-radix * multmax))) {
836 result = radix * result + digit;
837 }
838 if (inRange && i == endIndex && digit >= 0) {
839 return result;
840 }
841 }
842 if (digit < 0) {
843 throw NumberFormatException.forCharSequence(s, beginIndex,
844 endIndex, i - (digit < -1 ? 0 : 1));
845 }
846 throw new NumberFormatException(String.format(
847 "String value %s exceeds range of unsigned long.", s));
848 }
849
850 /**
851 * Parses the string argument as an unsigned decimal {@code long}. The
852 * characters in the string must all be decimal digits, except
853 * that the first character may be an ASCII plus sign {@code
854 * '+'} ({@code '\u005Cu002B'}). The resulting integer value
855 * is returned, exactly as if the argument and the radix 10 were
856 * given as arguments to the {@link
857 * #parseUnsignedLong(java.lang.String, int)} method.
858 *
859 * @param s a {@code String} containing the unsigned {@code long}
860 * representation to be parsed
861 * @return the unsigned {@code long} value represented by the decimal string argument
862 * @throws NumberFormatException if the string does not contain a
863 * parsable unsigned integer.
864 * @since 1.8
865 */
866 public static long parseUnsignedLong(String s) throws NumberFormatException {
867 return parseUnsignedLong(s, 10);
868 }
869
870 /**
871 * Returns a {@code Long} object holding the value
872 * extracted from the specified {@code String} when parsed
873 * with the radix given by the second argument. The first
874 * argument is interpreted as representing a signed
875 * {@code long} in the radix specified by the second
876 * argument, exactly as if the arguments were given to the {@link
877 * #parseLong(java.lang.String, int)} method. The result is a
878 * {@code Long} object that represents the {@code long}
879 * value specified by the string.
880 *
881 * <p>In other words, this method returns a {@code Long} object equal
882 * to the value of:
883 *
884 * <blockquote>
885 * {@code Long.valueOf(Long.parseLong(s, radix))}
886 * </blockquote>
887 *
888 * @param s the string to be parsed
889 * @param radix the radix to be used in interpreting {@code s}
890 * @return a {@code Long} object holding the value
891 * represented by the string argument in the specified
892 * radix.
893 * @throws NumberFormatException If the {@code String} does not
894 * contain a parsable {@code long}.
895 */
896 public static Long valueOf(String s, int radix) throws NumberFormatException {
897 return Long.valueOf(parseLong(s, radix));
898 }
899
900 /**
901 * Returns a {@code Long} object holding the value
902 * of the specified {@code String}. The argument is
903 * interpreted as representing a signed decimal {@code long},
904 * exactly as if the argument were given to the {@link
905 * #parseLong(java.lang.String)} method. The result is a
906 * {@code Long} object that represents the integer value
907 * specified by the string.
908 *
909 * <p>In other words, this method returns a {@code Long} object
910 * equal to the value of:
911 *
912 * <blockquote>
913 * {@code Long.valueOf(Long.parseLong(s))}
914 * </blockquote>
915 *
916 * @param s the string to be parsed.
917 * @return a {@code Long} object holding the value
918 * represented by the string argument.
919 * @throws NumberFormatException If the string cannot be parsed
920 * as a {@code long}.
921 */
922 public static Long valueOf(String s) throws NumberFormatException
923 {
924 return Long.valueOf(parseLong(s, 10));
925 }
926
927 @AOTSafeClassInitializer
928 private static final class LongCache {
929 private LongCache() {}
930
931 @Stable
932 static final Long[] cache;
933 static Long[] archivedCache;
934
935 static {
936 if (!PreviewFeatures.isEnabled()) {
937 int size = -(-128) + 127 + 1;
938
939 // Load and use the archived cache if it exists
940 CDS.initializeFromArchive(LongCache.class);
941 if (archivedCache == null) {
942 Long[] c = new Long[size];
943 long value = -128;
944 for(int i = 0; i < size; i++) {
945 c[i] = new Long(value++);
946 }
947 archivedCache = c;
948 }
949 cache = archivedCache;
950 assert cache.length == size;
951 } else {
952 cache = null;
953 assert archivedCache == null;
954 }
955 }
956 }
957
958 /**
959 * Returns a {@code Long} instance representing the specified
960 * {@code long} value.
961 * <div class="preview-block">
962 * <div class="preview-comment">
963 * <p>
964 * - When preview features are NOT enabled, {@code Long} is an identity class.
965 * If a new {@code Long} instance is not required, this method
966 * should generally be used in preference to the constructor
967 * {@link #Long(long)}, as this method is likely to yield
968 * significantly better space and time performance by caching
969 * frequently requested values.
970 * This method will always cache values in the range -128 to 127,
971 * inclusive, and may cache other values outside of this range.
972 * </p>
973 * <p>
974 * - When preview features are enabled, {@code Long} is a {@linkplain Class#isValue value class}.
975 * The {@code valueOf} behavior is the same as invoking the constructor,
976 * whether cached or not.
977 * </p>
978 * </div>
979 * </div>
980 *
981 * @param l a long value.
982 * @return a {@code Long} instance representing {@code l}.
983 * @since 1.5
984 */
985 @IntrinsicCandidate
986 @DeserializeConstructor
987 public static Long valueOf(long l) {
988 if (!PreviewFeatures.isEnabled()) {
989 if (l >= -128 && l <= 127) { // will cache
990 final int offset = 128;
991 return LongCache.cache[(int) l + offset];
992 }
993 }
994 return new Long(l);
995 }
996
997 /**
998 * Decodes a {@code String} into a {@code Long}.
999 * Accepts decimal, hexadecimal, and octal numbers given by the
1000 * following grammar:
1001 *
1002 * <blockquote>
1003 * <dl>
1004 * <dt><i>DecodableString:</i>
1005 * <dd><i>Sign<sub>opt</sub> DecimalNumeral</i>
1006 * <dd><i>Sign<sub>opt</sub></i> {@code 0x} <i>HexDigits</i>
1007 * <dd><i>Sign<sub>opt</sub></i> {@code 0X} <i>HexDigits</i>
1008 * <dd><i>Sign<sub>opt</sub></i> {@code #} <i>HexDigits</i>
1009 * <dd><i>Sign<sub>opt</sub></i> {@code 0} <i>OctalDigits</i>
1010 *
1011 * <dt><i>Sign:</i>
1012 * <dd>{@code -}
1013 * <dd>{@code +}
1014 * </dl>
1015 * </blockquote>
1016 *
1017 * <i>DecimalNumeral</i>, <i>HexDigits</i>, and <i>OctalDigits</i>
1018 * are as defined in section {@jls 3.10.1} of
1019 * <cite>The Java Language Specification</cite>,
1020 * except that underscores are not accepted between digits.
1021 *
1022 * <p>The sequence of characters following an optional
1023 * sign and/or radix specifier ("{@code 0x}", "{@code 0X}",
1024 * "{@code #}", or leading zero) is parsed as by the {@code
1025 * Long.parseLong} method with the indicated radix (10, 16, or 8).
1026 * This sequence of characters must represent a positive value or
1027 * a {@link NumberFormatException} will be thrown. The result is
1028 * negated if first character of the specified {@code String} is
1029 * the minus sign. No whitespace characters are permitted in the
1030 * {@code String}.
1031 *
1032 * @param nm the {@code String} to decode.
1033 * @return a {@code Long} object holding the {@code long}
1034 * value represented by {@code nm}
1035 * @throws NumberFormatException if the {@code String} does not
1036 * contain a parsable {@code long}.
1037 * @see java.lang.Long#parseLong(String, int)
1038 * @since 1.2
1039 */
1040 public static Long decode(String nm) throws NumberFormatException {
1041 int radix = 10;
1042 int index = 0;
1043 boolean negative = false;
1044 long result;
1045
1046 if (nm.isEmpty())
1047 throw new NumberFormatException("Zero length string");
1048 char firstChar = nm.charAt(0);
1049 // Handle sign, if present
1050 if (firstChar == '-') {
1051 negative = true;
1052 index++;
1053 } else if (firstChar == '+')
1054 index++;
1055
1056 // Handle radix specifier, if present
1057 if (nm.startsWith("0x", index) || nm.startsWith("0X", index)) {
1058 index += 2;
1059 radix = 16;
1060 }
1061 else if (nm.startsWith("#", index)) {
1062 index ++;
1063 radix = 16;
1064 }
1065 else if (nm.startsWith("0", index) && nm.length() > 1 + index) {
1066 index ++;
1067 radix = 8;
1068 }
1069
1070 if (nm.startsWith("-", index) || nm.startsWith("+", index))
1071 throw new NumberFormatException("Sign character in wrong position");
1072
1073 try {
1074 result = parseLong(nm, index, nm.length(), radix);
1075 result = negative ? -result : result;
1076 } catch (NumberFormatException e) {
1077 // If number is Long.MIN_VALUE, we'll end up here. The next line
1078 // handles this case, and causes any genuine format error to be
1079 // rethrown.
1080 String constant = negative ? ("-" + nm.substring(index))
1081 : nm.substring(index);
1082 result = parseLong(constant, radix);
1083 }
1084 return result;
1085 }
1086
1087 /**
1088 * The value of the {@code Long}.
1089 *
1090 * @serial
1091 */
1092 private final long value;
1093
1094 /**
1095 * Constructs a newly allocated {@code Long} object that
1096 * represents the specified {@code long} argument.
1097 *
1098 * @param value the value to be represented by the
1099 * {@code Long} object.
1100 *
1101 * @deprecated
1102 * It is rarely appropriate to use this constructor. The static factory
1103 * {@link #valueOf(long)} is generally a better choice, as it is
1104 * likely to yield significantly better space and time performance.
1105 */
1106 @Deprecated(since="9")
1107 public Long(long value) {
1108 this.value = value;
1109 }
1110
1111 /**
1112 * Constructs a newly allocated {@code Long} object that
1113 * represents the {@code long} value indicated by the
1114 * {@code String} parameter. The string is converted to a
1115 * {@code long} value in exactly the manner used by the
1116 * {@code parseLong} method for radix 10.
1117 *
1118 * @param s the {@code String} to be converted to a
1119 * {@code Long}.
1120 * @throws NumberFormatException if the {@code String} does not
1121 * contain a parsable {@code long}.
1122 *
1123 * @deprecated
1124 * It is rarely appropriate to use this constructor.
1125 * Use {@link #parseLong(String)} to convert a string to a
1126 * {@code long} primitive, or use {@link #valueOf(String)}
1127 * to convert a string to a {@code Long} object.
1128 */
1129 @Deprecated(since="9")
1130 public Long(String s) throws NumberFormatException {
1131 this.value = parseLong(s, 10);
1132 }
1133
1134 /**
1135 * Returns the value of this {@code Long} as a {@code byte} after
1136 * a narrowing primitive conversion.
1137 * @jls 5.1.3 Narrowing Primitive Conversion
1138 */
1139 public byte byteValue() {
1140 return (byte)value;
1141 }
1142
1143 /**
1144 * Returns the value of this {@code Long} as a {@code short} after
1145 * a narrowing primitive conversion.
1146 * @jls 5.1.3 Narrowing Primitive Conversion
1147 */
1148 public short shortValue() {
1149 return (short)value;
1150 }
1151
1152 /**
1153 * Returns the value of this {@code Long} as an {@code int} after
1154 * a narrowing primitive conversion.
1155 * @jls 5.1.3 Narrowing Primitive Conversion
1156 */
1157 public int intValue() {
1158 return (int)value;
1159 }
1160
1161 /**
1162 * Returns the value of this {@code Long} as a
1163 * {@code long} value.
1164 */
1165 @IntrinsicCandidate
1166 public long longValue() {
1167 return value;
1168 }
1169
1170 /**
1171 * Returns the value of this {@code Long} as a {@code float} after
1172 * a widening primitive conversion.
1173 * @jls 5.1.2 Widening Primitive Conversion
1174 */
1175 public float floatValue() {
1176 return (float)value;
1177 }
1178
1179 /**
1180 * Returns the value of this {@code Long} as a {@code double}
1181 * after a widening primitive conversion.
1182 * @jls 5.1.2 Widening Primitive Conversion
1183 */
1184 public double doubleValue() {
1185 return (double)value;
1186 }
1187
1188 /**
1189 * Returns a {@code String} object representing this
1190 * {@code Long}'s value. The value is converted to signed
1191 * decimal representation and returned as a string, exactly as if
1192 * the {@code long} value were given as an argument to the
1193 * {@link java.lang.Long#toString(long)} method.
1194 *
1195 * @return a string representation of the value of this object in
1196 * base 10.
1197 */
1198 public String toString() {
1199 return toString(value);
1200 }
1201
1202 /**
1203 * Returns a hash code for this {@code Long}. The result is
1204 * the exclusive OR of the two halves of the primitive
1205 * {@code long} value held by this {@code Long}
1206 * object. That is, the hashcode is the value of the expression:
1207 *
1208 * <blockquote>
1209 * {@code (int)(this.longValue()^(this.longValue()>>>32))}
1210 * </blockquote>
1211 *
1212 * @return a hash code value for this object.
1213 */
1214 @Override
1215 public int hashCode() {
1216 return Long.hashCode(value);
1217 }
1218
1219 /**
1220 * Returns a hash code for a {@code long} value; compatible with
1221 * {@code Long.hashCode()}.
1222 *
1223 * @param value the value to hash
1224 * @return a hash code value for a {@code long} value.
1225 * @since 1.8
1226 */
1227 public static int hashCode(long value) {
1228 return (int)(value ^ (value >>> 32));
1229 }
1230
1231 /**
1232 * Compares this object to the specified object. The result is
1233 * {@code true} if and only if the argument is not
1234 * {@code null} and is a {@code Long} object that
1235 * contains the same {@code long} value as this object.
1236 *
1237 * @param obj the object to compare with.
1238 * @return {@code true} if the objects are the same;
1239 * {@code false} otherwise.
1240 */
1241 public boolean equals(Object obj) {
1242 if (obj instanceof Long ell) {
1243 return value == ell.longValue();
1244 }
1245 return false;
1246 }
1247
1248 /**
1249 * Determines the {@code long} value of the system property
1250 * with the specified name.
1251 *
1252 * <p>The first argument is treated as the name of a system
1253 * property. System properties are accessible through the {@link
1254 * java.lang.System#getProperty(java.lang.String)} method. The
1255 * string value of this property is then interpreted as a {@code
1256 * long} value using the grammar supported by {@link Long#decode decode}
1257 * and a {@code Long} object representing this value is returned.
1258 *
1259 * <p>If there is no property with the specified name, if the
1260 * specified name is empty or {@code null}, or if the property
1261 * does not have the correct numeric format, then {@code null} is
1262 * returned.
1263 *
1264 * <p>In other words, this method returns a {@code Long} object
1265 * equal to the value of:
1266 *
1267 * <blockquote>
1268 * {@code getLong(nm, null)}
1269 * </blockquote>
1270 *
1271 * @param nm property name.
1272 * @return the {@code Long} value of the property.
1273 * @see java.lang.System#getProperty(java.lang.String)
1274 * @see java.lang.System#getProperty(java.lang.String, java.lang.String)
1275 */
1276 public static Long getLong(String nm) {
1277 return getLong(nm, null);
1278 }
1279
1280 /**
1281 * Determines the {@code long} value of the system property
1282 * with the specified name.
1283 *
1284 * <p>The first argument is treated as the name of a system
1285 * property. System properties are accessible through the {@link
1286 * java.lang.System#getProperty(java.lang.String)} method. The
1287 * string value of this property is then interpreted as a {@code
1288 * long} value using the grammar supported by {@link Long#decode decode}
1289 * and a {@code Long} object representing this value is returned.
1290 *
1291 * <p>The second argument is the default value. A {@code Long} object
1292 * that represents the value of the second argument is returned if there
1293 * is no property of the specified name, if the property does not have
1294 * the correct numeric format, or if the specified name is empty or null.
1295 *
1296 * <p>In other words, this method returns a {@code Long} object equal
1297 * to the value of:
1298 *
1299 * <blockquote>
1300 * {@code getLong(nm, Long.valueOf(val))}
1301 * </blockquote>
1302 *
1303 * but in practice it may be implemented in a manner such as:
1304 *
1305 * <blockquote><pre>
1306 * Long result = getLong(nm, null);
1307 * return (result == null) ? Long.valueOf(val) : result;
1308 * </pre></blockquote>
1309 *
1310 * to avoid the unnecessary allocation of a {@code Long} object when
1311 * the default value is not needed.
1312 *
1313 * @param nm property name.
1314 * @param val default value.
1315 * @return the {@code Long} value of the property.
1316 * @see java.lang.System#getProperty(java.lang.String)
1317 * @see java.lang.System#getProperty(java.lang.String, java.lang.String)
1318 */
1319 public static Long getLong(String nm, long val) {
1320 Long result = Long.getLong(nm, null);
1321 return (result == null) ? Long.valueOf(val) : result;
1322 }
1323
1324 /**
1325 * Returns the {@code long} value of the system property with
1326 * the specified name. The first argument is treated as the name
1327 * of a system property. System properties are accessible through
1328 * the {@link java.lang.System#getProperty(java.lang.String)}
1329 * method. The string value of this property is then interpreted
1330 * as a {@code long} value, as per the
1331 * {@link Long#decode decode} method, and a {@code Long} object
1332 * representing this value is returned; in summary:
1333 *
1334 * <ul>
1335 * <li>If the property value begins with the two ASCII characters
1336 * {@code 0x} or the ASCII character {@code #}, not followed by
1337 * a minus sign, then the rest of it is parsed as a hexadecimal integer
1338 * exactly as for the method {@link #valueOf(java.lang.String, int)}
1339 * with radix 16.
1340 * <li>If the property value begins with the ASCII character
1341 * {@code 0} followed by another character, it is parsed as
1342 * an octal integer exactly as by the method {@link
1343 * #valueOf(java.lang.String, int)} with radix 8.
1344 * <li>Otherwise the property value is parsed as a decimal
1345 * integer exactly as by the method
1346 * {@link #valueOf(java.lang.String, int)} with radix 10.
1347 * </ul>
1348 *
1349 * <p>Note that, in every case, neither {@code L}
1350 * ({@code '\u005Cu004C'}) nor {@code l}
1351 * ({@code '\u005Cu006C'}) is permitted to appear at the end
1352 * of the property value as a type indicator, as would be
1353 * permitted in Java programming language source code.
1354 *
1355 * <p>The second argument is the default value. The default value is
1356 * returned if there is no property of the specified name, if the
1357 * property does not have the correct numeric format, or if the
1358 * specified name is empty or {@code null}.
1359 *
1360 * @param nm property name.
1361 * @param val default value.
1362 * @return the {@code Long} value of the property.
1363 * @see System#getProperty(java.lang.String)
1364 * @see System#getProperty(java.lang.String, java.lang.String)
1365 */
1366 public static Long getLong(String nm, Long val) {
1367 String v = nm != null && !nm.isEmpty() ? System.getProperty(nm) : null;
1368 if (v != null) {
1369 try {
1370 return Long.decode(v);
1371 } catch (NumberFormatException e) {
1372 }
1373 }
1374 return val;
1375 }
1376
1377 /**
1378 * Compares two {@code Long} objects numerically.
1379 *
1380 * @param anotherLong the {@code Long} to be compared.
1381 * @return the value {@code 0} if this {@code Long} is
1382 * equal to the argument {@code Long}; a value less than
1383 * {@code 0} if this {@code Long} is numerically less
1384 * than the argument {@code Long}; and a value greater
1385 * than {@code 0} if this {@code Long} is numerically
1386 * greater than the argument {@code Long} (signed
1387 * comparison).
1388 * @since 1.2
1389 */
1390 public int compareTo(Long anotherLong) {
1391 return compare(this.value, anotherLong.value);
1392 }
1393
1394 /**
1395 * Compares two {@code long} values numerically.
1396 * The value returned is identical to what would be returned by:
1397 * <pre>
1398 * Long.valueOf(x).compareTo(Long.valueOf(y))
1399 * </pre>
1400 *
1401 * @param x the first {@code long} to compare
1402 * @param y the second {@code long} to compare
1403 * @return the value {@code 0} if {@code x == y};
1404 * a value less than {@code 0} if {@code x < y}; and
1405 * a value greater than {@code 0} if {@code x > y}
1406 * @since 1.7
1407 */
1408 public static int compare(long x, long y) {
1409 return (x < y) ? -1 : ((x == y) ? 0 : 1);
1410 }
1411
1412 /**
1413 * Compares two {@code long} values numerically treating the values
1414 * as unsigned.
1415 *
1416 * @param x the first {@code long} to compare
1417 * @param y the second {@code long} to compare
1418 * @return the value {@code 0} if {@code x == y}; a value less
1419 * than {@code 0} if {@code x < y} as unsigned values; and
1420 * a value greater than {@code 0} if {@code x > y} as
1421 * unsigned values
1422 * @since 1.8
1423 */
1424 @IntrinsicCandidate
1425 public static int compareUnsigned(long x, long y) {
1426 return compare(x + MIN_VALUE, y + MIN_VALUE);
1427 }
1428
1429
1430 /**
1431 * Returns the unsigned quotient of dividing the first argument by
1432 * the second where each argument and the result is interpreted as
1433 * an unsigned value.
1434 *
1435 * <p>Note that in two's complement arithmetic, the three other
1436 * basic arithmetic operations of add, subtract, and multiply are
1437 * bit-wise identical if the two operands are regarded as both
1438 * being signed or both being unsigned. Therefore separate {@code
1439 * addUnsigned}, etc. methods are not provided.
1440 *
1441 * @param dividend the value to be divided
1442 * @param divisor the value doing the dividing
1443 * @return the unsigned quotient of the first argument divided by
1444 * the second argument
1445 * @throws ArithmeticException if the divisor is zero
1446 * @see #remainderUnsigned
1447 * @since 1.8
1448 */
1449 @IntrinsicCandidate
1450 public static long divideUnsigned(long dividend, long divisor) {
1451 /* See Hacker's Delight (2nd ed), section 9.3 */
1452 if (divisor >= 0) {
1453 final long q = (dividend >>> 1) / divisor << 1;
1454 final long r = dividend - q * divisor;
1455 return q + ((r | ~(r - divisor)) >>> (Long.SIZE - 1));
1456 }
1457 return (dividend & ~(dividend - divisor)) >>> (Long.SIZE - 1);
1458 }
1459
1460 /**
1461 * Returns the unsigned remainder from dividing the first argument
1462 * by the second where each argument and the result is interpreted
1463 * as an unsigned value.
1464 *
1465 * @param dividend the value to be divided
1466 * @param divisor the value doing the dividing
1467 * @return the unsigned remainder of the first argument divided by
1468 * the second argument
1469 * @throws ArithmeticException if the divisor is zero
1470 * @see #divideUnsigned
1471 * @since 1.8
1472 */
1473 @IntrinsicCandidate
1474 public static long remainderUnsigned(long dividend, long divisor) {
1475 /* See Hacker's Delight (2nd ed), section 9.3 */
1476 if (divisor >= 0) {
1477 final long q = (dividend >>> 1) / divisor << 1;
1478 final long r = dividend - q * divisor;
1479 /*
1480 * Here, 0 <= r < 2 * divisor
1481 * (1) When 0 <= r < divisor, the remainder is simply r.
1482 * (2) Otherwise the remainder is r - divisor.
1483 *
1484 * In case (1), r - divisor < 0. Applying ~ produces a long with
1485 * sign bit 0, so >> produces 0. The returned value is thus r.
1486 *
1487 * In case (2), a similar reasoning shows that >> produces -1,
1488 * so the returned value is r - divisor.
1489 */
1490 return r - ((~(r - divisor) >> (Long.SIZE - 1)) & divisor);
1491 }
1492 /*
1493 * (1) When dividend >= 0, the remainder is dividend.
1494 * (2) Otherwise
1495 * (2.1) When dividend < divisor, the remainder is dividend.
1496 * (2.2) Otherwise the remainder is dividend - divisor
1497 *
1498 * A reasoning similar to the above shows that the returned value
1499 * is as expected.
1500 */
1501 return dividend - (((dividend & ~(dividend - divisor)) >> (Long.SIZE - 1)) & divisor);
1502 }
1503
1504 // Bit Twiddling
1505
1506 /**
1507 * The number of bits used to represent a {@code long} value in two's
1508 * complement binary form.
1509 *
1510 * @since 1.5
1511 */
1512 @Native public static final int SIZE = 64;
1513
1514 /**
1515 * The number of bytes used to represent a {@code long} value in two's
1516 * complement binary form.
1517 *
1518 * @since 1.8
1519 */
1520 public static final int BYTES = SIZE / Byte.SIZE;
1521
1522 /**
1523 * Returns a {@code long} value with at most a single one-bit, in the
1524 * position of the highest-order ("leftmost") one-bit in the specified
1525 * {@code long} value. Returns zero if the specified value has no
1526 * one-bits in its two's complement binary representation, that is, if it
1527 * is equal to zero.
1528 *
1529 * @param i the value whose highest one bit is to be computed
1530 * @return a {@code long} value with a single one-bit, in the position
1531 * of the highest-order one-bit in the specified value, or zero if
1532 * the specified value is itself equal to zero.
1533 * @since 1.5
1534 */
1535 public static long highestOneBit(long i) {
1536 return i & (MIN_VALUE >>> numberOfLeadingZeros(i));
1537 }
1538
1539 /**
1540 * Returns a {@code long} value with at most a single one-bit, in the
1541 * position of the lowest-order ("rightmost") one-bit in the specified
1542 * {@code long} value. Returns zero if the specified value has no
1543 * one-bits in its two's complement binary representation, that is, if it
1544 * is equal to zero.
1545 *
1546 * @param i the value whose lowest one bit is to be computed
1547 * @return a {@code long} value with a single one-bit, in the position
1548 * of the lowest-order one-bit in the specified value, or zero if
1549 * the specified value is itself equal to zero.
1550 * @since 1.5
1551 */
1552 public static long lowestOneBit(long i) {
1553 // HD, Section 2-1
1554 return i & -i;
1555 }
1556
1557 /**
1558 * Returns the number of zero bits preceding the highest-order
1559 * ("leftmost") one-bit in the two's complement binary representation
1560 * of the specified {@code long} value. Returns 64 if the
1561 * specified value has no one-bits in its two's complement representation,
1562 * in other words if it is equal to zero.
1563 *
1564 * <p>Note that this method is closely related to the logarithm base 2.
1565 * For all positive {@code long} values x:
1566 * <ul>
1567 * <li>floor(log<sub>2</sub>(x)) = {@code 63 - numberOfLeadingZeros(x)}
1568 * <li>ceil(log<sub>2</sub>(x)) = {@code 64 - numberOfLeadingZeros(x - 1)}
1569 * </ul>
1570 *
1571 * @param i the value whose number of leading zeros is to be computed
1572 * @return the number of zero bits preceding the highest-order
1573 * ("leftmost") one-bit in the two's complement binary representation
1574 * of the specified {@code long} value, or 64 if the value
1575 * is equal to zero.
1576 * @since 1.5
1577 */
1578 @IntrinsicCandidate
1579 public static int numberOfLeadingZeros(long i) {
1580 int x = (int)(i >>> 32);
1581 return x == 0 ? 32 + Integer.numberOfLeadingZeros((int)i)
1582 : Integer.numberOfLeadingZeros(x);
1583 }
1584
1585 /**
1586 * Returns the number of zero bits following the lowest-order ("rightmost")
1587 * one-bit in the two's complement binary representation of the specified
1588 * {@code long} value. Returns 64 if the specified value has no
1589 * one-bits in its two's complement representation, in other words if it is
1590 * equal to zero.
1591 *
1592 * @param i the value whose number of trailing zeros is to be computed
1593 * @return the number of zero bits following the lowest-order ("rightmost")
1594 * one-bit in the two's complement binary representation of the
1595 * specified {@code long} value, or 64 if the value is equal
1596 * to zero.
1597 * @since 1.5
1598 */
1599 @IntrinsicCandidate
1600 public static int numberOfTrailingZeros(long i) {
1601 int x = (int)i;
1602 return x == 0 ? 32 + Integer.numberOfTrailingZeros((int)(i >>> 32))
1603 : Integer.numberOfTrailingZeros(x);
1604 }
1605
1606 /**
1607 * Returns the number of one-bits in the two's complement binary
1608 * representation of the specified {@code long} value. This function is
1609 * sometimes referred to as the <i>population count</i>.
1610 *
1611 * @param i the value whose bits are to be counted
1612 * @return the number of one-bits in the two's complement binary
1613 * representation of the specified {@code long} value.
1614 * @since 1.5
1615 */
1616 @IntrinsicCandidate
1617 public static int bitCount(long i) {
1618 // HD, Figure 5-2
1619 i = i - ((i >>> 1) & 0x5555555555555555L);
1620 i = (i & 0x3333333333333333L) + ((i >>> 2) & 0x3333333333333333L);
1621 i = (i + (i >>> 4)) & 0x0f0f0f0f0f0f0f0fL;
1622 i = i + (i >>> 8);
1623 i = i + (i >>> 16);
1624 i = i + (i >>> 32);
1625 return (int)i & 0x7f;
1626 }
1627
1628 /**
1629 * Returns the value obtained by rotating the two's complement binary
1630 * representation of the specified {@code long} value left by the
1631 * specified number of bits. (Bits shifted out of the left hand, or
1632 * high-order, side reenter on the right, or low-order.)
1633 *
1634 * <p>Note that left rotation with a negative distance is equivalent to
1635 * right rotation: {@code rotateLeft(val, -distance) == rotateRight(val,
1636 * distance)}. Note also that rotation by any multiple of 64 is a
1637 * no-op, so all but the last six bits of the rotation distance can be
1638 * ignored, even if the distance is negative: {@code rotateLeft(val,
1639 * distance) == rotateLeft(val, distance & 0x3F)}.
1640 *
1641 * @param i the value whose bits are to be rotated left
1642 * @param distance the number of bit positions to rotate left
1643 * @return the value obtained by rotating the two's complement binary
1644 * representation of the specified {@code long} value left by the
1645 * specified number of bits.
1646 * @since 1.5
1647 */
1648 public static long rotateLeft(long i, int distance) {
1649 return (i << distance) | (i >>> -distance);
1650 }
1651
1652 /**
1653 * Returns the value obtained by rotating the two's complement binary
1654 * representation of the specified {@code long} value right by the
1655 * specified number of bits. (Bits shifted out of the right hand, or
1656 * low-order, side reenter on the left, or high-order.)
1657 *
1658 * <p>Note that right rotation with a negative distance is equivalent to
1659 * left rotation: {@code rotateRight(val, -distance) == rotateLeft(val,
1660 * distance)}. Note also that rotation by any multiple of 64 is a
1661 * no-op, so all but the last six bits of the rotation distance can be
1662 * ignored, even if the distance is negative: {@code rotateRight(val,
1663 * distance) == rotateRight(val, distance & 0x3F)}.
1664 *
1665 * @param i the value whose bits are to be rotated right
1666 * @param distance the number of bit positions to rotate right
1667 * @return the value obtained by rotating the two's complement binary
1668 * representation of the specified {@code long} value right by the
1669 * specified number of bits.
1670 * @since 1.5
1671 */
1672 public static long rotateRight(long i, int distance) {
1673 return (i >>> distance) | (i << -distance);
1674 }
1675
1676 /**
1677 * Returns the value obtained by reversing the order of the bits in the
1678 * two's complement binary representation of the specified {@code long}
1679 * value.
1680 *
1681 * @param i the value to be reversed
1682 * @return the value obtained by reversing order of the bits in the
1683 * specified {@code long} value.
1684 * @since 1.5
1685 */
1686 @IntrinsicCandidate
1687 public static long reverse(long i) {
1688 // HD, Figure 7-1
1689 i = (i & 0x5555555555555555L) << 1 | (i >>> 1) & 0x5555555555555555L;
1690 i = (i & 0x3333333333333333L) << 2 | (i >>> 2) & 0x3333333333333333L;
1691 i = (i & 0x0f0f0f0f0f0f0f0fL) << 4 | (i >>> 4) & 0x0f0f0f0f0f0f0f0fL;
1692
1693 return reverseBytes(i);
1694 }
1695
1696 /**
1697 * Returns the value obtained by compressing the bits of the
1698 * specified {@code long} value, {@code i}, in accordance with
1699 * the specified bit mask.
1700 * <p>
1701 * For each one-bit value {@code mb} of the mask, from least
1702 * significant to most significant, the bit value of {@code i} at
1703 * the same bit location as {@code mb} is assigned to the compressed
1704 * value contiguously starting from the least significant bit location.
1705 * All the upper remaining bits of the compressed value are set
1706 * to zero.
1707 *
1708 * @apiNote
1709 * Consider the simple case of compressing the digits of a hexadecimal
1710 * value:
1711 * {@snippet lang="java" :
1712 * // Compressing drink to food
1713 * compress(0xCAFEBABEL, 0xFF00FFF0L) == 0xCABABL
1714 * }
1715 * Starting from the least significant hexadecimal digit at position 0
1716 * from the right, the mask {@code 0xFF00FFF0} selects hexadecimal digits
1717 * at positions 1, 2, 3, 6 and 7 of {@code 0xCAFEBABE}. The selected digits
1718 * occur in the resulting compressed value contiguously from digit position
1719 * 0 in the same order.
1720 * <p>
1721 * The following identities all return {@code true} and are helpful to
1722 * understand the behaviour of {@code compress}:
1723 * {@snippet lang="java" :
1724 * // Returns 1 if the bit at position n is one
1725 * compress(x, 1L << n) == (x >> n & 1)
1726 *
1727 * // Logical shift right
1728 * compress(x, -1L << n) == x >>> n
1729 *
1730 * // Any bits not covered by the mask are ignored
1731 * compress(x, m) == compress(x & m, m)
1732 *
1733 * // Compressing a value by itself
1734 * compress(m, m) == (m == -1 || m == 0) ? m : (1L << bitCount(m)) - 1
1735 *
1736 * // Expanding then compressing with the same mask
1737 * compress(expand(x, m), m) == x & compress(m, m)
1738 * }
1739 * <p>
1740 * The Sheep And Goats (SAG) operation (see Hacker's Delight, Second Edition, section 7.7)
1741 * can be implemented as follows:
1742 * {@snippet lang="java" :
1743 * long compressLeft(long i, long mask) {
1744 * // This implementation follows the description in Hacker's Delight which
1745 * // is informative. A more optimal implementation is:
1746 * // Long.compress(i, mask) << -Long.bitCount(mask)
1747 * return Long.reverse(
1748 * Long.compress(Long.reverse(i), Long.reverse(mask)));
1749 * }
1750 *
1751 * long sag(long i, long mask) {
1752 * return compressLeft(i, mask) | Long.compress(i, ~mask);
1753 * }
1754 *
1755 * // Separate the sheep from the goats
1756 * sag(0x00000000_CAFEBABEL, 0xFFFFFFFF_FF00FFF0L) == 0x00000000_CABABFEEL
1757 * }
1758 *
1759 * @param i the value whose bits are to be compressed
1760 * @param mask the bit mask
1761 * @return the compressed value
1762 * @see #expand
1763 * @since 19
1764 */
1765 @IntrinsicCandidate
1766 public static long compress(long i, long mask) {
1767 // See Hacker's Delight (2nd ed) section 7.4 Compress, or Generalized Extract
1768
1769 i = i & mask; // Clear irrelevant bits
1770 long maskCount = ~mask << 1; // Count 0's to right
1771
1772 for (int j = 0; j < 6; j++) {
1773 // Parallel prefix
1774 // Mask prefix identifies bits of the mask that have an odd number of 0's to the right
1775 long maskPrefix = parallelSuffix(maskCount);
1776 // Bits to move
1777 long maskMove = maskPrefix & mask;
1778 // Compress mask
1779 mask = (mask ^ maskMove) | (maskMove >>> (1 << j));
1780 // Bits of i to be moved
1781 long t = i & maskMove;
1782 // Compress i
1783 i = (i ^ t) | (t >>> (1 << j));
1784 // Adjust the mask count by identifying bits that have 0 to the right
1785 maskCount = maskCount & ~maskPrefix;
1786 }
1787 return i;
1788 }
1789
1790 /**
1791 * Returns the value obtained by expanding the bits of the
1792 * specified {@code long} value, {@code i}, in accordance with
1793 * the specified bit mask.
1794 * <p>
1795 * For each one-bit value {@code mb} of the mask, from least
1796 * significant to most significant, the next contiguous bit value
1797 * of {@code i} starting at the least significant bit is assigned
1798 * to the expanded value at the same bit location as {@code mb}.
1799 * All other remaining bits of the expanded value are set to zero.
1800 *
1801 * @apiNote
1802 * Consider the simple case of expanding the digits of a hexadecimal
1803 * value:
1804 * {@snippet lang="java" :
1805 * expand(0x0000CABABL, 0xFF00FFF0L) == 0xCA00BAB0L
1806 * }
1807 * Starting from the least significant hexadecimal digit at position 0
1808 * from the right, the mask {@code 0xFF00FFF0} selects the first five
1809 * hexadecimal digits of {@code 0x0000CABAB}. The selected digits occur
1810 * in the resulting expanded value in order at positions 1, 2, 3, 6, and 7.
1811 * <p>
1812 * The following identities all return {@code true} and are helpful to
1813 * understand the behaviour of {@code expand}:
1814 * {@snippet lang="java" :
1815 * // Logically shift right the bit at position 0
1816 * expand(x, 1L << n) == (x & 1) << n
1817 *
1818 * // Logically shift right
1819 * expand(x, -1L << n) == x << n
1820 *
1821 * // Expanding all bits returns the mask
1822 * expand(-1L, m) == m
1823 *
1824 * // Any bits not covered by the mask are ignored
1825 * expand(x, m) == expand(x, m) & m
1826 *
1827 * // Compressing then expanding with the same mask
1828 * expand(compress(x, m), m) == x & m
1829 * }
1830 * <p>
1831 * The select operation for determining the position of the one-bit with
1832 * index {@code n} in a {@code long} value can be implemented as follows:
1833 * {@snippet lang="java" :
1834 * long select(long i, long n) {
1835 * // the one-bit in i (the mask) with index n
1836 * long nthBit = Long.expand(1L << n, i);
1837 * // the bit position of the one-bit with index n
1838 * return Long.numberOfTrailingZeros(nthBit);
1839 * }
1840 *
1841 * // The one-bit with index 0 is at bit position 1
1842 * select(0b10101010_10101010, 0) == 1
1843 * // The one-bit with index 3 is at bit position 7
1844 * select(0b10101010_10101010, 3) == 7
1845 * }
1846 *
1847 * @param i the value whose bits are to be expanded
1848 * @param mask the bit mask
1849 * @return the expanded value
1850 * @see #compress
1851 * @since 19
1852 */
1853 @IntrinsicCandidate
1854 public static long expand(long i, long mask) {
1855 // Save original mask
1856 long originalMask = mask;
1857 // Count 0's to right
1858 long maskCount = ~mask << 1;
1859 long maskPrefix = parallelSuffix(maskCount);
1860 // Bits to move
1861 long maskMove1 = maskPrefix & mask;
1862 // Compress mask
1863 mask = (mask ^ maskMove1) | (maskMove1 >>> (1 << 0));
1864 maskCount = maskCount & ~maskPrefix;
1865
1866 maskPrefix = parallelSuffix(maskCount);
1867 // Bits to move
1868 long maskMove2 = maskPrefix & mask;
1869 // Compress mask
1870 mask = (mask ^ maskMove2) | (maskMove2 >>> (1 << 1));
1871 maskCount = maskCount & ~maskPrefix;
1872
1873 maskPrefix = parallelSuffix(maskCount);
1874 // Bits to move
1875 long maskMove3 = maskPrefix & mask;
1876 // Compress mask
1877 mask = (mask ^ maskMove3) | (maskMove3 >>> (1 << 2));
1878 maskCount = maskCount & ~maskPrefix;
1879
1880 maskPrefix = parallelSuffix(maskCount);
1881 // Bits to move
1882 long maskMove4 = maskPrefix & mask;
1883 // Compress mask
1884 mask = (mask ^ maskMove4) | (maskMove4 >>> (1 << 3));
1885 maskCount = maskCount & ~maskPrefix;
1886
1887 maskPrefix = parallelSuffix(maskCount);
1888 // Bits to move
1889 long maskMove5 = maskPrefix & mask;
1890 // Compress mask
1891 mask = (mask ^ maskMove5) | (maskMove5 >>> (1 << 4));
1892 maskCount = maskCount & ~maskPrefix;
1893
1894 maskPrefix = parallelSuffix(maskCount);
1895 // Bits to move
1896 long maskMove6 = maskPrefix & mask;
1897
1898 long t = i << (1 << 5);
1899 i = (i & ~maskMove6) | (t & maskMove6);
1900 t = i << (1 << 4);
1901 i = (i & ~maskMove5) | (t & maskMove5);
1902 t = i << (1 << 3);
1903 i = (i & ~maskMove4) | (t & maskMove4);
1904 t = i << (1 << 2);
1905 i = (i & ~maskMove3) | (t & maskMove3);
1906 t = i << (1 << 1);
1907 i = (i & ~maskMove2) | (t & maskMove2);
1908 t = i << (1 << 0);
1909 i = (i & ~maskMove1) | (t & maskMove1);
1910
1911 // Clear irrelevant bits
1912 return i & originalMask;
1913 }
1914
1915 @ForceInline
1916 private static long parallelSuffix(long maskCount) {
1917 long maskPrefix = maskCount ^ (maskCount << 1);
1918 maskPrefix = maskPrefix ^ (maskPrefix << 2);
1919 maskPrefix = maskPrefix ^ (maskPrefix << 4);
1920 maskPrefix = maskPrefix ^ (maskPrefix << 8);
1921 maskPrefix = maskPrefix ^ (maskPrefix << 16);
1922 maskPrefix = maskPrefix ^ (maskPrefix << 32);
1923 return maskPrefix;
1924 }
1925
1926 /**
1927 * Returns the signum function of the specified {@code long} value. (The
1928 * return value is -1 if the specified value is negative; 0 if the
1929 * specified value is zero; and 1 if the specified value is positive.)
1930 *
1931 * @param i the value whose signum is to be computed
1932 * @return the signum function of the specified {@code long} value.
1933 * @since 1.5
1934 */
1935 public static int signum(long i) {
1936 // HD, Section 2-7
1937 return (int) ((i >> 63) | (-i >>> 63));
1938 }
1939
1940 /**
1941 * Returns the value obtained by reversing the order of the bytes in the
1942 * two's complement representation of the specified {@code long} value.
1943 *
1944 * @param i the value whose bytes are to be reversed
1945 * @return the value obtained by reversing the bytes in the specified
1946 * {@code long} value.
1947 * @since 1.5
1948 */
1949 @IntrinsicCandidate
1950 public static long reverseBytes(long i) {
1951 i = (i & 0x00ff00ff00ff00ffL) << 8 | (i >>> 8) & 0x00ff00ff00ff00ffL;
1952 return (i << 48) | ((i & 0xffff0000L) << 16) |
1953 ((i >>> 16) & 0xffff0000L) | (i >>> 48);
1954 }
1955
1956 /**
1957 * Adds two {@code long} values together as per the + operator.
1958 *
1959 * @param a the first operand
1960 * @param b the second operand
1961 * @return the sum of {@code a} and {@code b}
1962 * @see java.util.function.BinaryOperator
1963 * @since 1.8
1964 */
1965 public static long sum(long a, long b) {
1966 return a + b;
1967 }
1968
1969 /**
1970 * Returns the greater of two {@code long} values
1971 * as if by calling {@link Math#max(long, long) Math.max}.
1972 *
1973 * @param a the first operand
1974 * @param b the second operand
1975 * @return the greater of {@code a} and {@code b}
1976 * @see java.util.function.BinaryOperator
1977 * @since 1.8
1978 */
1979 public static long max(long a, long b) {
1980 return Math.max(a, b);
1981 }
1982
1983 /**
1984 * Returns the smaller of two {@code long} values
1985 * as if by calling {@link Math#min(long, long) Math.min}.
1986 *
1987 * @param a the first operand
1988 * @param b the second operand
1989 * @return the smaller of {@code a} and {@code b}
1990 * @see java.util.function.BinaryOperator
1991 * @since 1.8
1992 */
1993 public static long min(long a, long b) {
1994 return Math.min(a, b);
1995 }
1996
1997 /**
1998 * Returns an {@link Optional} containing the nominal descriptor for this
1999 * instance, which is the instance itself.
2000 *
2001 * @return an {@link Optional} describing the {@linkplain Long} instance
2002 * @since 12
2003 */
2004 @Override
2005 public Optional<Long> describeConstable() {
2006 return Optional.of(this);
2007 }
2008
2009 /**
2010 * Resolves this instance as a {@link ConstantDesc}, the result of which is
2011 * the instance itself.
2012 *
2013 * @param lookup ignored
2014 * @return the {@linkplain Long} instance
2015 * @since 12
2016 */
2017 @Override
2018 public Long resolveConstantDesc(MethodHandles.Lookup lookup) {
2019 return this;
2020 }
2021
2022 /** use serialVersionUID from JDK 1.0.2 for interoperability */
2023 @java.io.Serial
2024 @Native private static final long serialVersionUID = 4290774380558885855L;
2025 }