1 /*
2 * Copyright (c) 1994, 2024, 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.value.DeserializeConstructor;
38 import jdk.internal.util.DecimalDigits;
39 import jdk.internal.vm.annotation.ForceInline;
40 import jdk.internal.vm.annotation.IntrinsicCandidate;
41 import jdk.internal.vm.annotation.Stable;
42
43 import static java.lang.Character.digit;
44 import static java.lang.String.COMPACT_STRINGS;
45 import static java.lang.String.LATIN1;
46 import static java.lang.String.UTF16;
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 * @author Lee Boynton
82 * @author Arthur van Hoff
83 * @author Josh Bloch
84 * @author Joseph D. Darcy
85 * @since 1.0
86 */
87 @jdk.internal.MigratedValueClass
88 @jdk.internal.ValueBased
89 public final class Long extends Number
90 implements Comparable<Long>, Constable, ConstantDesc {
91 /**
92 * A constant holding the minimum value a {@code long} can
93 * have, -2<sup>63</sup>.
94 */
95 @Native public static final long MIN_VALUE = 0x8000000000000000L;
96
97 /**
98 * A constant holding the maximum value a {@code long} can
99 * have, 2<sup>63</sup>-1.
100 */
101 @Native public static final long MAX_VALUE = 0x7fffffffffffffffL;
102
103 /**
104 * The {@code Class} instance representing the primitive type
105 * {@code long}.
106 *
107 * @since 1.1
108 */
109 public static final Class<Long> TYPE = Class.getPrimitiveClass("long");
110
111 /**
112 * Returns a string representation of the first argument in the
113 * radix specified by the second argument.
114 *
115 * <p>If the radix is smaller than {@code Character.MIN_RADIX}
116 * or larger than {@code Character.MAX_RADIX}, then the radix
117 * {@code 10} is used instead.
118 *
119 * <p>If the first argument is negative, the first element of the
120 * result is the ASCII minus sign {@code '-'}
121 * ({@code '\u005Cu002d'}). If the first argument is not
122 * negative, no sign character appears in the result.
123 *
124 * <p>The remaining characters of the result represent the magnitude
125 * of the first argument. If the magnitude is zero, it is
126 * represented by a single zero character {@code '0'}
127 * ({@code '\u005Cu0030'}); otherwise, the first character of
128 * the representation of the magnitude will not be the zero
129 * character. The following ASCII characters are used as digits:
130 *
131 * <blockquote>
132 * {@code 0123456789abcdefghijklmnopqrstuvwxyz}
133 * </blockquote>
134 *
135 * These are {@code '\u005Cu0030'} through
136 * {@code '\u005Cu0039'} and {@code '\u005Cu0061'} through
137 * {@code '\u005Cu007a'}. If {@code radix} is
138 * <var>N</var>, then the first <var>N</var> of these characters
139 * are used as radix-<var>N</var> digits in the order shown. Thus,
140 * the digits for hexadecimal (radix 16) are
141 * {@code 0123456789abcdef}. If uppercase letters are
142 * desired, the {@link java.lang.String#toUpperCase()} method may
143 * be called on the result:
144 *
145 * <blockquote>
146 * {@code Long.toString(n, 16).toUpperCase()}
147 * </blockquote>
148 *
149 * @param i a {@code long} to be converted to a string.
150 * @param radix the radix to use in the string representation.
151 * @return a string representation of the argument in the specified radix.
152 * @see java.lang.Character#MAX_RADIX
153 * @see java.lang.Character#MIN_RADIX
154 */
155 public static String toString(long i, int radix) {
156 if (radix < Character.MIN_RADIX || radix > Character.MAX_RADIX)
157 radix = 10;
158 if (radix == 10)
159 return toString(i);
160
161 if (COMPACT_STRINGS) {
162 byte[] buf = new byte[65];
163 int charPos = 64;
164 boolean negative = (i < 0);
165
166 if (!negative) {
167 i = -i;
168 }
169
170 while (i <= -radix) {
171 buf[charPos--] = (byte)Integer.digits[(int)(-(i % radix))];
172 i = i / radix;
173 }
174 buf[charPos] = (byte)Integer.digits[(int)(-i)];
175
176 if (negative) {
177 buf[--charPos] = '-';
178 }
179 return StringLatin1.newString(buf, charPos, (65 - charPos));
180 }
181 return toStringUTF16(i, radix);
182 }
183
184 private static String toStringUTF16(long i, int radix) {
185 byte[] buf = new byte[65 * 2];
186 int charPos = 64;
187 boolean negative = (i < 0);
188 if (!negative) {
189 i = -i;
190 }
191 while (i <= -radix) {
192 StringUTF16.putChar(buf, charPos--, Integer.digits[(int)(-(i % radix))]);
193 i = i / radix;
194 }
195 StringUTF16.putChar(buf, charPos, Integer.digits[(int)(-i)]);
196 if (negative) {
197 StringUTF16.putChar(buf, --charPos, '-');
198 }
199 return StringUTF16.newString(buf, charPos, (65 - charPos));
200 }
201
202 /**
203 * Returns a string representation of the first argument as an
204 * unsigned integer value in the radix specified by the second
205 * argument.
206 *
207 * <p>If the radix is smaller than {@code Character.MIN_RADIX}
208 * or larger than {@code Character.MAX_RADIX}, then the radix
209 * {@code 10} is used instead.
210 *
211 * <p>Note that since the first argument is treated as an unsigned
212 * value, no leading sign character is printed.
213 *
214 * <p>If the magnitude is zero, it is represented by a single zero
215 * character {@code '0'} ({@code '\u005Cu0030'}); otherwise,
216 * the first character of the representation of the magnitude will
217 * not be the zero character.
218 *
219 * <p>The behavior of radixes and the characters used as digits
220 * are the same as {@link #toString(long, int) toString}.
221 *
222 * @param i an integer to be converted to an unsigned string.
223 * @param radix the radix to use in the string representation.
224 * @return an unsigned string representation of the argument in the specified radix.
225 * @see #toString(long, int)
226 * @since 1.8
227 */
228 public static String toUnsignedString(long i, int radix) {
229 if (i >= 0)
230 return toString(i, radix);
231 else {
232 return switch (radix) {
233 case 2 -> toBinaryString(i);
234 case 4 -> toUnsignedString0(i, 2);
235 case 8 -> toOctalString(i);
236 case 10 -> {
237 /*
238 * We can get the effect of an unsigned division by 10
239 * on a long value by first shifting right, yielding a
240 * positive value, and then dividing by 5. This
241 * allows the last digit and preceding digits to be
242 * isolated more quickly than by an initial conversion
243 * to BigInteger.
244 */
245 long quot = (i >>> 1) / 5;
246 long rem = i - quot * 10;
247 yield toString(quot) + rem;
248 }
249 case 16 -> toHexString(i);
250 case 32 -> toUnsignedString0(i, 5);
251 default -> toUnsignedBigInteger(i).toString(radix);
252 };
253 }
254 }
255
256 /**
257 * Return a BigInteger equal to the unsigned value of the
258 * argument.
259 */
260 private static BigInteger toUnsignedBigInteger(long i) {
261 if (i >= 0L)
262 return BigInteger.valueOf(i);
263 else {
264 int upper = (int) (i >>> 32);
265 int lower = (int) i;
266
267 // return (upper << 32) + lower
268 return (BigInteger.valueOf(Integer.toUnsignedLong(upper))).shiftLeft(32).
269 add(BigInteger.valueOf(Integer.toUnsignedLong(lower)));
270 }
271 }
272
273 /**
274 * Returns a string representation of the {@code long}
275 * argument as an unsigned integer in base 16.
276 *
277 * <p>The unsigned {@code long} value is the argument plus
278 * 2<sup>64</sup> if the argument is negative; otherwise, it is
279 * equal to the argument. This value is converted to a string of
280 * ASCII digits in hexadecimal (base 16) with no extra
281 * leading {@code 0}s.
282 *
283 * <p>The value of the argument can be recovered from the returned
284 * string {@code s} by calling {@link
285 * Long#parseUnsignedLong(String, int) Long.parseUnsignedLong(s,
286 * 16)}.
287 *
288 * <p>If the unsigned magnitude is zero, it is represented by a
289 * single zero character {@code '0'} ({@code '\u005Cu0030'});
290 * otherwise, the first character of the representation of the
291 * unsigned magnitude will not be the zero character. The
292 * following characters are used as hexadecimal digits:
293 *
294 * <blockquote>
295 * {@code 0123456789abcdef}
296 * </blockquote>
297 *
298 * These are the characters {@code '\u005Cu0030'} through
299 * {@code '\u005Cu0039'} and {@code '\u005Cu0061'} through
300 * {@code '\u005Cu0066'}. If uppercase letters are desired,
301 * the {@link java.lang.String#toUpperCase()} method may be called
302 * on the result:
303 *
304 * <blockquote>
305 * {@code Long.toHexString(n).toUpperCase()}
306 * </blockquote>
307 *
308 * @apiNote
309 * The {@link java.util.HexFormat} class provides formatting and parsing
310 * of byte arrays and primitives to return a string or adding to an {@link Appendable}.
311 * {@code HexFormat} formats and parses uppercase or lowercase hexadecimal characters,
312 * with leading zeros and for byte arrays includes for each byte
313 * a delimiter, prefix, and suffix.
314 *
315 * @param i a {@code long} to be converted to a string.
316 * @return the string representation of the unsigned {@code long}
317 * value represented by the argument in hexadecimal
318 * (base 16).
319 * @see java.util.HexFormat
320 * @see #parseUnsignedLong(String, int)
321 * @see #toUnsignedString(long, int)
322 * @since 1.0.2
323 */
324 public static String toHexString(long i) {
325 return toUnsignedString0(i, 4);
326 }
327
328 /**
329 * Returns a string representation of the {@code long}
330 * argument as an unsigned integer in base 8.
331 *
332 * <p>The unsigned {@code long} value is the argument plus
333 * 2<sup>64</sup> if the argument is negative; otherwise, it is
334 * equal to the argument. This value is converted to a string of
335 * ASCII digits in octal (base 8) with no extra leading
336 * {@code 0}s.
337 *
338 * <p>The value of the argument can be recovered from the returned
339 * string {@code s} by calling {@link
340 * Long#parseUnsignedLong(String, int) Long.parseUnsignedLong(s,
341 * 8)}.
342 *
343 * <p>If the unsigned magnitude is zero, it is represented by a
344 * single zero character {@code '0'} ({@code '\u005Cu0030'});
345 * otherwise, the first character of the representation of the
346 * unsigned magnitude will not be the zero character. The
347 * following characters are used as octal digits:
348 *
349 * <blockquote>
350 * {@code 01234567}
351 * </blockquote>
352 *
353 * These are the characters {@code '\u005Cu0030'} through
354 * {@code '\u005Cu0037'}.
355 *
356 * @param i a {@code long} to be converted to a string.
357 * @return the string representation of the unsigned {@code long}
358 * value represented by the argument in octal (base 8).
359 * @see #parseUnsignedLong(String, int)
360 * @see #toUnsignedString(long, int)
361 * @since 1.0.2
362 */
363 public static String toOctalString(long i) {
364 return toUnsignedString0(i, 3);
365 }
366
367 /**
368 * Returns a string representation of the {@code long}
369 * argument as an unsigned integer in base 2.
370 *
371 * <p>The unsigned {@code long} value is the argument plus
372 * 2<sup>64</sup> if the argument is negative; otherwise, it is
373 * equal to the argument. This value is converted to a string of
374 * ASCII digits in binary (base 2) with no extra leading
375 * {@code 0}s.
376 *
377 * <p>The value of the argument can be recovered from the returned
378 * string {@code s} by calling {@link
379 * Long#parseUnsignedLong(String, int) Long.parseUnsignedLong(s,
380 * 2)}.
381 *
382 * <p>If the unsigned magnitude is zero, it is represented by a
383 * single zero character {@code '0'} ({@code '\u005Cu0030'});
384 * otherwise, the first character of the representation of the
385 * unsigned magnitude will not be the zero character. The
386 * characters {@code '0'} ({@code '\u005Cu0030'}) and {@code
387 * '1'} ({@code '\u005Cu0031'}) are used as binary digits.
388 *
389 * @param i a {@code long} to be converted to a string.
390 * @return the string representation of the unsigned {@code long}
391 * value represented by the argument in binary (base 2).
392 * @see #parseUnsignedLong(String, int)
393 * @see #toUnsignedString(long, int)
394 * @since 1.0.2
395 */
396 public static String toBinaryString(long i) {
397 return toUnsignedString0(i, 1);
398 }
399
400 /**
401 * Format a long (treated as unsigned) into a String.
402 * @param val the value to format
403 * @param shift the log2 of the base to format in (4 for hex, 3 for octal, 1 for binary)
404 */
405 static String toUnsignedString0(long val, int shift) {
406 // assert shift > 0 && shift <=5 : "Illegal shift value";
407 int mag = Long.SIZE - Long.numberOfLeadingZeros(val);
408 int chars = Math.max(((mag + (shift - 1)) / shift), 1);
409 if (COMPACT_STRINGS) {
410 byte[] buf = new byte[chars];
411 formatUnsignedLong0(val, shift, buf, 0, chars);
412 return new String(buf, LATIN1);
413 } else {
414 byte[] buf = new byte[chars * 2];
415 formatUnsignedLong0UTF16(val, shift, buf, 0, chars);
416 return new String(buf, UTF16);
417 }
418 }
419
420 /**
421 * Format a long (treated as unsigned) into a byte buffer (LATIN1 version). If
422 * {@code len} exceeds the formatted ASCII representation of {@code val},
423 * {@code buf} will be padded with leading zeroes.
424 *
425 * @param val the unsigned long to format
426 * @param shift the log2 of the base to format in (4 for hex, 3 for octal, 1 for binary)
427 * @param buf the byte buffer to write to
428 * @param offset the offset in the destination buffer to start at
429 * @param len the number of characters to write
430 */
431 private static void formatUnsignedLong0(long val, int shift, byte[] buf, int offset, int len) {
432 int charPos = offset + len;
433 int radix = 1 << shift;
434 int mask = radix - 1;
435 do {
436 buf[--charPos] = (byte)Integer.digits[((int) val) & mask];
437 val >>>= shift;
438 } while (charPos > offset);
439 }
440
441 /**
442 * Format a long (treated as unsigned) into a byte buffer (UTF16 version). If
443 * {@code len} exceeds the formatted ASCII representation of {@code val},
444 * {@code buf} will be padded with leading zeroes.
445 *
446 * @param val the unsigned long to format
447 * @param shift the log2 of the base to format in (4 for hex, 3 for octal, 1 for binary)
448 * @param buf the byte buffer to write to
449 * @param offset the offset in the destination buffer to start at
450 * @param len the number of characters to write
451 */
452 private static void formatUnsignedLong0UTF16(long val, int shift, byte[] buf, int offset, int len) {
453 int charPos = offset + len;
454 int radix = 1 << shift;
455 int mask = radix - 1;
456 do {
457 StringUTF16.putChar(buf, --charPos, Integer.digits[((int) val) & mask]);
458 val >>>= shift;
459 } while (charPos > offset);
460 }
461
462 /**
463 * Returns a {@code String} object representing the specified
464 * {@code long}. The argument is converted to signed decimal
465 * representation and returned as a string, exactly as if the
466 * argument and the radix 10 were given as arguments to the {@link
467 * #toString(long, int)} method.
468 *
469 * @param i a {@code long} to be converted.
470 * @return a string representation of the argument in base 10.
471 */
472 public static String toString(long i) {
473 int size = DecimalDigits.stringSize(i);
474 if (COMPACT_STRINGS) {
475 byte[] buf = new byte[size];
476 StringLatin1.getChars(i, size, buf);
477 return new String(buf, LATIN1);
478 } else {
479 byte[] buf = new byte[size * 2];
480 StringUTF16.getChars(i, size, buf);
481 return new String(buf, UTF16);
482 }
483 }
484
485 /**
486 * Returns a string representation of the argument as an unsigned
487 * decimal value.
488 *
489 * The argument is converted to unsigned decimal representation
490 * and returned as a string exactly as if the argument and radix
491 * 10 were given as arguments to the {@link #toUnsignedString(long,
492 * int)} method.
493 *
494 * @param i an integer to be converted to an unsigned string.
495 * @return an unsigned string representation of the argument.
496 * @see #toUnsignedString(long, int)
497 * @since 1.8
498 */
499 public static String toUnsignedString(long i) {
500 return toUnsignedString(i, 10);
501 }
502
503 /**
504 * Parses the string argument as a signed {@code long} in the
505 * radix specified by the second argument. The characters in the
506 * string must all be digits of the specified radix (as determined
507 * by whether {@link java.lang.Character#digit(char, int)} returns
508 * a nonnegative value), except that the first character may be an
509 * ASCII minus sign {@code '-'} ({@code '\u005Cu002D'}) to
510 * indicate a negative value or an ASCII plus sign {@code '+'}
511 * ({@code '\u005Cu002B'}) to indicate a positive value. The
512 * resulting {@code long} value is returned.
513 *
514 * <p>Note that neither the character {@code L}
515 * ({@code '\u005Cu004C'}) nor {@code l}
516 * ({@code '\u005Cu006C'}) is permitted to appear at the end
517 * of the string as a type indicator, as would be permitted in
518 * Java programming language source code - except that either
519 * {@code L} or {@code l} may appear as a digit for a
520 * radix greater than or equal to 22.
521 *
522 * <p>An exception of type {@code NumberFormatException} is
523 * thrown if any of the following situations occurs:
524 * <ul>
525 *
526 * <li>The first argument is {@code null} or is a string of
527 * length zero.
528 *
529 * <li>The {@code radix} is either smaller than {@link
530 * java.lang.Character#MIN_RADIX} or larger than {@link
531 * java.lang.Character#MAX_RADIX}.
532 *
533 * <li>Any character of the string is not a digit of the specified
534 * radix, except that the first character may be a minus sign
535 * {@code '-'} ({@code '\u005Cu002d'}) or plus sign {@code
536 * '+'} ({@code '\u005Cu002B'}) provided that the string is
537 * longer than length 1.
538 *
539 * <li>The value represented by the string is not a value of type
540 * {@code long}.
541 * </ul>
542 *
543 * <p>Examples:
544 * <blockquote><pre>
545 * parseLong("0", 10) returns 0L
546 * parseLong("473", 10) returns 473L
547 * parseLong("+42", 10) returns 42L
548 * parseLong("-0", 10) returns 0L
549 * parseLong("-FF", 16) returns -255L
550 * parseLong("1100110", 2) returns 102L
551 * parseLong("99", 8) throws a NumberFormatException
552 * parseLong("Hazelnut", 10) throws a NumberFormatException
553 * parseLong("Hazelnut", 36) returns 1356099454469L
554 * </pre></blockquote>
555 *
556 * @param s the {@code String} containing the
557 * {@code long} representation to be parsed.
558 * @param radix the radix to be used while parsing {@code s}.
559 * @return the {@code long} represented by the string argument in
560 * the specified radix.
561 * @throws NumberFormatException if the string does not contain a
562 * parsable {@code long}.
563 */
564 public static long parseLong(String s, int radix)
565 throws NumberFormatException {
566 if (s == null) {
567 throw new NumberFormatException("Cannot parse null string");
568 }
569
570 if (radix < Character.MIN_RADIX) {
571 throw new NumberFormatException(String.format(
572 "radix %s less than Character.MIN_RADIX", radix));
573 }
574
575 if (radix > Character.MAX_RADIX) {
576 throw new NumberFormatException(String.format(
577 "radix %s greater than Character.MAX_RADIX", radix));
578 }
579
580 int len = s.length();
581 if (len == 0) {
582 throw NumberFormatException.forInputString("", radix);
583 }
584 int digit = ~0xFF;
585 int i = 0;
586 char firstChar = s.charAt(i++);
587 if (firstChar != '-' && firstChar != '+') {
588 digit = digit(firstChar, radix);
589 }
590 if (digit >= 0 || digit == ~0xFF && len > 1) {
591 long limit = firstChar != '-' ? MIN_VALUE + 1 : MIN_VALUE;
592 long multmin = limit / radix;
593 long result = -(digit & 0xFF);
594 boolean inRange = true;
595 /* Accumulating negatively avoids surprises near MAX_VALUE */
596 while (i < len && (digit = digit(s.charAt(i++), radix)) >= 0
597 && (inRange = result > multmin
598 || result == multmin && digit <= (int) (radix * multmin - limit))) {
599 result = radix * result - digit;
600 }
601 if (inRange && i == len && digit >= 0) {
602 return firstChar != '-' ? -result : result;
603 }
604 }
605 throw NumberFormatException.forInputString(s, radix);
606 }
607
608 /**
609 * Parses the {@link CharSequence} argument as a signed {@code long} in
610 * the specified {@code radix}, beginning at the specified
611 * {@code beginIndex} and extending to {@code endIndex - 1}.
612 *
613 * <p>The method does not take steps to guard against the
614 * {@code CharSequence} being mutated while parsing.
615 *
616 * @param s the {@code CharSequence} containing the {@code long}
617 * representation to be parsed
618 * @param beginIndex the beginning index, inclusive.
619 * @param endIndex the ending index, exclusive.
620 * @param radix the radix to be used while parsing {@code s}.
621 * @return the signed {@code long} represented by the subsequence in
622 * the specified radix.
623 * @throws NullPointerException if {@code s} is null.
624 * @throws IndexOutOfBoundsException if {@code beginIndex} is
625 * negative, or if {@code beginIndex} is greater than
626 * {@code endIndex} or if {@code endIndex} is greater than
627 * {@code s.length()}.
628 * @throws NumberFormatException if the {@code CharSequence} does not
629 * contain a parsable {@code long} in the specified
630 * {@code radix}, or if {@code radix} is either smaller than
631 * {@link java.lang.Character#MIN_RADIX} or larger than
632 * {@link java.lang.Character#MAX_RADIX}.
633 * @since 9
634 */
635 public static long parseLong(CharSequence s, int beginIndex, int endIndex, int radix)
636 throws NumberFormatException {
637 Objects.requireNonNull(s);
638 Objects.checkFromToIndex(beginIndex, endIndex, s.length());
639
640 if (radix < Character.MIN_RADIX) {
641 throw new NumberFormatException(String.format(
642 "radix %s less than Character.MIN_RADIX", radix));
643 }
644
645 if (radix > Character.MAX_RADIX) {
646 throw new NumberFormatException(String.format(
647 "radix %s greater than Character.MAX_RADIX", radix));
648 }
649
650 /*
651 * While s can be concurrently modified, it is ensured that each
652 * of its characters is read at most once, from lower to higher indices.
653 * This is obtained by reading them using the pattern s.charAt(i++),
654 * and by not updating i anywhere else.
655 */
656 if (beginIndex == endIndex) {
657 throw NumberFormatException.forInputString("", radix);
658 }
659 int digit = ~0xFF; // ~0xFF means firstChar char is sign
660 int i = beginIndex;
661 char firstChar = s.charAt(i++);
662 if (firstChar != '-' && firstChar != '+') {
663 digit = digit(firstChar, radix);
664 }
665 if (digit >= 0 || digit == ~0xFF && endIndex - beginIndex > 1) {
666 long limit = firstChar != '-' ? MIN_VALUE + 1 : MIN_VALUE;
667 long multmin = limit / radix;
668 long result = -(digit & 0xFF);
669 boolean inRange = true;
670 /* Accumulating negatively avoids surprises near MAX_VALUE */
671 while (i < endIndex && (digit = digit(s.charAt(i++), radix)) >= 0
672 && (inRange = result > multmin
673 || result == multmin && digit <= (int) (radix * multmin - limit))) {
674 result = radix * result - digit;
675 }
676 if (inRange && i == endIndex && digit >= 0) {
677 return firstChar != '-' ? -result : result;
678 }
679 }
680 throw NumberFormatException.forCharSequence(s, beginIndex,
681 endIndex, i - (digit < -1 ? 0 : 1));
682 }
683
684 /**
685 * Parses the string argument as a signed decimal {@code long}.
686 * The characters in the string must all be decimal digits, except
687 * that the first character may be an ASCII minus sign {@code '-'}
688 * ({@code \u005Cu002D'}) to indicate a negative value or an
689 * ASCII plus sign {@code '+'} ({@code '\u005Cu002B'}) to
690 * indicate a positive value. The resulting {@code long} value is
691 * returned, exactly as if the argument and the radix {@code 10}
692 * were given as arguments to the {@link
693 * #parseLong(java.lang.String, int)} method.
694 *
695 * <p>Note that neither the character {@code L}
696 * ({@code '\u005Cu004C'}) nor {@code l}
697 * ({@code '\u005Cu006C'}) is permitted to appear at the end
698 * of the string as a type indicator, as would be permitted in
699 * Java programming language source code.
700 *
701 * @param s a {@code String} containing the {@code long}
702 * representation to be parsed
703 * @return the {@code long} represented by the argument in
704 * decimal.
705 * @throws NumberFormatException if the string does not contain a
706 * parsable {@code long}.
707 */
708 public static long parseLong(String s) throws NumberFormatException {
709 return parseLong(s, 10);
710 }
711
712 /**
713 * Parses the string argument as an unsigned {@code long} in the
714 * radix specified by the second argument. An unsigned integer
715 * maps the values usually associated with negative numbers to
716 * positive numbers larger than {@code MAX_VALUE}.
717 *
718 * The characters in the string must all be digits of the
719 * specified radix (as determined by whether {@link
720 * java.lang.Character#digit(char, int)} returns a nonnegative
721 * value), except that the first character may be an ASCII plus
722 * sign {@code '+'} ({@code '\u005Cu002B'}). The resulting
723 * integer value is returned.
724 *
725 * <p>An exception of type {@code NumberFormatException} is
726 * thrown if any of the following situations occurs:
727 * <ul>
728 * <li>The first argument is {@code null} or is a string of
729 * length zero.
730 *
731 * <li>The radix is either smaller than
732 * {@link java.lang.Character#MIN_RADIX} or
733 * larger than {@link java.lang.Character#MAX_RADIX}.
734 *
735 * <li>Any character of the string is not a digit of the specified
736 * radix, except that the first character may be a plus sign
737 * {@code '+'} ({@code '\u005Cu002B'}) provided that the
738 * string is longer than length 1.
739 *
740 * <li>The value represented by the string is larger than the
741 * largest unsigned {@code long}, 2<sup>64</sup>-1.
742 *
743 * </ul>
744 *
745 *
746 * @param s the {@code String} containing the unsigned integer
747 * representation to be parsed
748 * @param radix the radix to be used while parsing {@code s}.
749 * @return the unsigned {@code long} represented by the string
750 * argument in the specified radix.
751 * @throws NumberFormatException if the {@code String}
752 * does not contain a parsable {@code long}.
753 * @since 1.8
754 */
755 public static long parseUnsignedLong(String s, int radix)
756 throws NumberFormatException {
757 if (s == null) {
758 throw new NumberFormatException("Cannot parse null string");
759 }
760
761 if (radix < Character.MIN_RADIX) {
762 throw new NumberFormatException(String.format(
763 "radix %s less than Character.MIN_RADIX", radix));
764 }
765
766 if (radix > Character.MAX_RADIX) {
767 throw new NumberFormatException(String.format(
768 "radix %s greater than Character.MAX_RADIX", radix));
769 }
770
771 int len = s.length();
772 if (len == 0) {
773 throw NumberFormatException.forInputString(s, radix);
774 }
775 int i = 0;
776 char firstChar = s.charAt(i++);
777 if (firstChar == '-') {
778 throw new NumberFormatException(String.format(
779 "Illegal leading minus sign on unsigned string %s.", s));
780 }
781 int digit = ~0xFF;
782 if (firstChar != '+') {
783 digit = digit(firstChar, radix);
784 }
785 if (digit >= 0 || digit == ~0xFF && len > 1) {
786 long multmax = divideUnsigned(-1L, radix); // -1L is max unsigned long
787 long result = digit & 0xFF;
788 boolean inRange = true;
789 while (i < len && (digit = digit(s.charAt(i++), radix)) >= 0
790 && (inRange = compareUnsigned(result, multmax) < 0
791 || result == multmax && digit < (int) (-radix * multmax))) {
792 result = radix * result + digit;
793 }
794 if (inRange && i == len && digit >= 0) {
795 return result;
796 }
797 }
798 if (digit < 0) {
799 throw NumberFormatException.forInputString(s, radix);
800 }
801 throw new NumberFormatException(String.format(
802 "String value %s exceeds range of unsigned long.", s));
803 }
804
805 /**
806 * Parses the {@link CharSequence} argument as an unsigned {@code long} in
807 * the specified {@code radix}, beginning at the specified
808 * {@code beginIndex} and extending to {@code endIndex - 1}.
809 *
810 * <p>The method does not take steps to guard against the
811 * {@code CharSequence} being mutated while parsing.
812 *
813 * @param s the {@code CharSequence} containing the unsigned
814 * {@code long} representation to be parsed
815 * @param beginIndex the beginning index, inclusive.
816 * @param endIndex the ending index, exclusive.
817 * @param radix the radix to be used while parsing {@code s}.
818 * @return the unsigned {@code long} represented by the subsequence in
819 * the specified radix.
820 * @throws NullPointerException if {@code s} is null.
821 * @throws IndexOutOfBoundsException if {@code beginIndex} is
822 * negative, or if {@code beginIndex} is greater than
823 * {@code endIndex} or if {@code endIndex} is greater than
824 * {@code s.length()}.
825 * @throws NumberFormatException if the {@code CharSequence} does not
826 * contain a parsable unsigned {@code long} in the specified
827 * {@code radix}, or if {@code radix} is either smaller than
828 * {@link java.lang.Character#MIN_RADIX} or larger than
829 * {@link java.lang.Character#MAX_RADIX}.
830 * @since 9
831 */
832 public static long parseUnsignedLong(CharSequence s, int beginIndex, int endIndex, int radix)
833 throws NumberFormatException {
834 Objects.requireNonNull(s);
835 Objects.checkFromToIndex(beginIndex, endIndex, s.length());
836
837 if (radix < Character.MIN_RADIX) {
838 throw new NumberFormatException(String.format(
839 "radix %s less than Character.MIN_RADIX", radix));
840 }
841
842 if (radix > Character.MAX_RADIX) {
843 throw new NumberFormatException(String.format(
844 "radix %s greater than Character.MAX_RADIX", radix));
845 }
846
847 /*
848 * While s can be concurrently modified, it is ensured that each
849 * of its characters is read at most once, from lower to higher indices.
850 * This is obtained by reading them using the pattern s.charAt(i++),
851 * and by not updating i anywhere else.
852 */
853 if (beginIndex == endIndex) {
854 throw NumberFormatException.forInputString("", radix);
855 }
856 int i = beginIndex;
857 char firstChar = s.charAt(i++);
858 if (firstChar == '-') {
859 throw new NumberFormatException(
860 "Illegal leading minus sign on unsigned string " + s + ".");
861 }
862 int digit = ~0xFF;
863 if (firstChar != '+') {
864 digit = digit(firstChar, radix);
865 }
866 if (digit >= 0 || digit == ~0xFF && endIndex - beginIndex > 1) {
867 long multmax = divideUnsigned(-1L, radix); // -1L is max unsigned long
868 long result = digit & 0xFF;
869 boolean inRange = true;
870 while (i < endIndex && (digit = digit(s.charAt(i++), radix)) >= 0
871 && (inRange = compareUnsigned(result, multmax) < 0
872 || result == multmax && digit < (int) (-radix * multmax))) {
873 result = radix * result + digit;
874 }
875 if (inRange && i == endIndex && digit >= 0) {
876 return result;
877 }
878 }
879 if (digit < 0) {
880 throw NumberFormatException.forCharSequence(s, beginIndex,
881 endIndex, i - (digit < -1 ? 0 : 1));
882 }
883 throw new NumberFormatException(String.format(
884 "String value %s exceeds range of unsigned long.", s));
885 }
886
887 /**
888 * Parses the string argument as an unsigned decimal {@code long}. The
889 * characters in the string must all be decimal digits, except
890 * that the first character may be an ASCII plus sign {@code
891 * '+'} ({@code '\u005Cu002B'}). The resulting integer value
892 * is returned, exactly as if the argument and the radix 10 were
893 * given as arguments to the {@link
894 * #parseUnsignedLong(java.lang.String, int)} method.
895 *
896 * @param s a {@code String} containing the unsigned {@code long}
897 * representation to be parsed
898 * @return the unsigned {@code long} value represented by the decimal string argument
899 * @throws NumberFormatException if the string does not contain a
900 * parsable unsigned integer.
901 * @since 1.8
902 */
903 public static long parseUnsignedLong(String s) throws NumberFormatException {
904 return parseUnsignedLong(s, 10);
905 }
906
907 /**
908 * Returns a {@code Long} object holding the value
909 * extracted from the specified {@code String} when parsed
910 * with the radix given by the second argument. The first
911 * argument is interpreted as representing a signed
912 * {@code long} in the radix specified by the second
913 * argument, exactly as if the arguments were given to the {@link
914 * #parseLong(java.lang.String, int)} method. The result is a
915 * {@code Long} object that represents the {@code long}
916 * value specified by the string.
917 *
918 * <p>In other words, this method returns a {@code Long} object equal
919 * to the value of:
920 *
921 * <blockquote>
922 * {@code Long.valueOf(Long.parseLong(s, radix))}
923 * </blockquote>
924 *
925 * @param s the string to be parsed
926 * @param radix the radix to be used in interpreting {@code s}
927 * @return a {@code Long} object holding the value
928 * represented by the string argument in the specified
929 * radix.
930 * @throws NumberFormatException If the {@code String} does not
931 * contain a parsable {@code long}.
932 */
933 public static Long valueOf(String s, int radix) throws NumberFormatException {
934 return Long.valueOf(parseLong(s, radix));
935 }
936
937 /**
938 * Returns a {@code Long} object holding the value
939 * of the specified {@code String}. The argument is
940 * interpreted as representing a signed decimal {@code long},
941 * exactly as if the argument were given to the {@link
942 * #parseLong(java.lang.String)} method. The result is a
943 * {@code Long} object that represents the integer value
944 * specified by the string.
945 *
946 * <p>In other words, this method returns a {@code Long} object
947 * equal to the value of:
948 *
949 * <blockquote>
950 * {@code Long.valueOf(Long.parseLong(s))}
951 * </blockquote>
952 *
953 * @param s the string to be parsed.
954 * @return a {@code Long} object holding the value
955 * represented by the string argument.
956 * @throws NumberFormatException If the string cannot be parsed
957 * as a {@code long}.
958 */
959 public static Long valueOf(String s) throws NumberFormatException
960 {
961 return Long.valueOf(parseLong(s, 10));
962 }
963
964 private static final class LongCache {
965 private LongCache() {}
966
967 @Stable
968 static final Long[] cache;
969 static Long[] archivedCache;
970
971 static {
972 int size = -(-128) + 127 + 1;
973
974 // Load and use the archived cache if it exists
975 CDS.initializeFromArchive(LongCache.class);
976 if (archivedCache == null) {
977 Long[] c = new Long[size];
978 long value = -128;
979 for(int i = 0; i < size; i++) {
980 c[i] = new Long(value++);
981 }
982 archivedCache = c;
983 }
984 cache = archivedCache;
985 assert cache.length == size;
986 }
987 }
988
989 /**
990 * Returns a {@code Long} instance representing the specified
991 * {@code long} value.
992 * If a new {@code Long} instance is not required, this method
993 * should generally be used in preference to the constructor
994 * {@link #Long(long)}, as this method is likely to yield
995 * significantly better space and time performance by caching
996 * frequently requested values.
997 *
998 * This method will always cache values in the range -128 to 127,
999 * inclusive, and may cache other values outside of this range.
1000 *
1001 * @param l a long value.
1002 * @return a {@code Long} instance representing {@code l}.
1003 * @since 1.5
1004 */
1005 @IntrinsicCandidate
1006 @DeserializeConstructor
1007 public static Long valueOf(long l) {
1008 final int offset = 128;
1009 if (l >= -128 && l <= 127) { // will cache
1010 return LongCache.cache[(int)l + offset];
1011 }
1012 return new Long(l);
1013 }
1014
1015 /**
1016 * Decodes a {@code String} into a {@code Long}.
1017 * Accepts decimal, hexadecimal, and octal numbers given by the
1018 * following grammar:
1019 *
1020 * <blockquote>
1021 * <dl>
1022 * <dt><i>DecodableString:</i>
1023 * <dd><i>Sign<sub>opt</sub> DecimalNumeral</i>
1024 * <dd><i>Sign<sub>opt</sub></i> {@code 0x} <i>HexDigits</i>
1025 * <dd><i>Sign<sub>opt</sub></i> {@code 0X} <i>HexDigits</i>
1026 * <dd><i>Sign<sub>opt</sub></i> {@code #} <i>HexDigits</i>
1027 * <dd><i>Sign<sub>opt</sub></i> {@code 0} <i>OctalDigits</i>
1028 *
1029 * <dt><i>Sign:</i>
1030 * <dd>{@code -}
1031 * <dd>{@code +}
1032 * </dl>
1033 * </blockquote>
1034 *
1035 * <i>DecimalNumeral</i>, <i>HexDigits</i>, and <i>OctalDigits</i>
1036 * are as defined in section {@jls 3.10.1} of
1037 * <cite>The Java Language Specification</cite>,
1038 * except that underscores are not accepted between digits.
1039 *
1040 * <p>The sequence of characters following an optional
1041 * sign and/or radix specifier ("{@code 0x}", "{@code 0X}",
1042 * "{@code #}", or leading zero) is parsed as by the {@code
1043 * Long.parseLong} method with the indicated radix (10, 16, or 8).
1044 * This sequence of characters must represent a positive value or
1045 * a {@link NumberFormatException} will be thrown. The result is
1046 * negated if first character of the specified {@code String} is
1047 * the minus sign. No whitespace characters are permitted in the
1048 * {@code String}.
1049 *
1050 * @param nm the {@code String} to decode.
1051 * @return a {@code Long} object holding the {@code long}
1052 * value represented by {@code nm}
1053 * @throws NumberFormatException if the {@code String} does not
1054 * contain a parsable {@code long}.
1055 * @see java.lang.Long#parseLong(String, int)
1056 * @since 1.2
1057 */
1058 public static Long decode(String nm) throws NumberFormatException {
1059 int radix = 10;
1060 int index = 0;
1061 boolean negative = false;
1062 long result;
1063
1064 if (nm.isEmpty())
1065 throw new NumberFormatException("Zero length string");
1066 char firstChar = nm.charAt(0);
1067 // Handle sign, if present
1068 if (firstChar == '-') {
1069 negative = true;
1070 index++;
1071 } else if (firstChar == '+')
1072 index++;
1073
1074 // Handle radix specifier, if present
1075 if (nm.startsWith("0x", index) || nm.startsWith("0X", index)) {
1076 index += 2;
1077 radix = 16;
1078 }
1079 else if (nm.startsWith("#", index)) {
1080 index ++;
1081 radix = 16;
1082 }
1083 else if (nm.startsWith("0", index) && nm.length() > 1 + index) {
1084 index ++;
1085 radix = 8;
1086 }
1087
1088 if (nm.startsWith("-", index) || nm.startsWith("+", index))
1089 throw new NumberFormatException("Sign character in wrong position");
1090
1091 try {
1092 result = parseLong(nm, index, nm.length(), radix);
1093 result = negative ? -result : result;
1094 } catch (NumberFormatException e) {
1095 // If number is Long.MIN_VALUE, we'll end up here. The next line
1096 // handles this case, and causes any genuine format error to be
1097 // rethrown.
1098 String constant = negative ? ("-" + nm.substring(index))
1099 : nm.substring(index);
1100 result = parseLong(constant, radix);
1101 }
1102 return result;
1103 }
1104
1105 /**
1106 * The value of the {@code Long}.
1107 *
1108 * @serial
1109 */
1110 private final long value;
1111
1112 /**
1113 * Constructs a newly allocated {@code Long} object that
1114 * represents the specified {@code long} argument.
1115 *
1116 * @param value the value to be represented by the
1117 * {@code Long} object.
1118 *
1119 * @deprecated
1120 * It is rarely appropriate to use this constructor. The static factory
1121 * {@link #valueOf(long)} is generally a better choice, as it is
1122 * likely to yield significantly better space and time performance.
1123 */
1124 @Deprecated(since="9", forRemoval = true)
1125 public Long(long value) {
1126 this.value = value;
1127 }
1128
1129 /**
1130 * Constructs a newly allocated {@code Long} object that
1131 * represents the {@code long} value indicated by the
1132 * {@code String} parameter. The string is converted to a
1133 * {@code long} value in exactly the manner used by the
1134 * {@code parseLong} method for radix 10.
1135 *
1136 * @param s the {@code String} to be converted to a
1137 * {@code Long}.
1138 * @throws NumberFormatException if the {@code String} does not
1139 * contain a parsable {@code long}.
1140 *
1141 * @deprecated
1142 * It is rarely appropriate to use this constructor.
1143 * Use {@link #parseLong(String)} to convert a string to a
1144 * {@code long} primitive, or use {@link #valueOf(String)}
1145 * to convert a string to a {@code Long} object.
1146 */
1147 @Deprecated(since="9", forRemoval = true)
1148 public Long(String s) throws NumberFormatException {
1149 this.value = parseLong(s, 10);
1150 }
1151
1152 /**
1153 * Returns the value of this {@code Long} as a {@code byte} after
1154 * a narrowing primitive conversion.
1155 * @jls 5.1.3 Narrowing Primitive Conversion
1156 */
1157 public byte byteValue() {
1158 return (byte)value;
1159 }
1160
1161 /**
1162 * Returns the value of this {@code Long} as a {@code short} after
1163 * a narrowing primitive conversion.
1164 * @jls 5.1.3 Narrowing Primitive Conversion
1165 */
1166 public short shortValue() {
1167 return (short)value;
1168 }
1169
1170 /**
1171 * Returns the value of this {@code Long} as an {@code int} after
1172 * a narrowing primitive conversion.
1173 * @jls 5.1.3 Narrowing Primitive Conversion
1174 */
1175 public int intValue() {
1176 return (int)value;
1177 }
1178
1179 /**
1180 * Returns the value of this {@code Long} as a
1181 * {@code long} value.
1182 */
1183 @IntrinsicCandidate
1184 public long longValue() {
1185 return value;
1186 }
1187
1188 /**
1189 * Returns the value of this {@code Long} as a {@code float} after
1190 * a widening primitive conversion.
1191 * @jls 5.1.2 Widening Primitive Conversion
1192 */
1193 public float floatValue() {
1194 return (float)value;
1195 }
1196
1197 /**
1198 * Returns the value of this {@code Long} as a {@code double}
1199 * after a widening primitive conversion.
1200 * @jls 5.1.2 Widening Primitive Conversion
1201 */
1202 public double doubleValue() {
1203 return (double)value;
1204 }
1205
1206 /**
1207 * Returns a {@code String} object representing this
1208 * {@code Long}'s value. The value is converted to signed
1209 * decimal representation and returned as a string, exactly as if
1210 * the {@code long} value were given as an argument to the
1211 * {@link java.lang.Long#toString(long)} method.
1212 *
1213 * @return a string representation of the value of this object in
1214 * base 10.
1215 */
1216 public String toString() {
1217 return toString(value);
1218 }
1219
1220 /**
1221 * Returns a hash code for this {@code Long}. The result is
1222 * the exclusive OR of the two halves of the primitive
1223 * {@code long} value held by this {@code Long}
1224 * object. That is, the hashcode is the value of the expression:
1225 *
1226 * <blockquote>
1227 * {@code (int)(this.longValue()^(this.longValue()>>>32))}
1228 * </blockquote>
1229 *
1230 * @return a hash code value for this object.
1231 */
1232 @Override
1233 public int hashCode() {
1234 return Long.hashCode(value);
1235 }
1236
1237 /**
1238 * Returns a hash code for a {@code long} value; compatible with
1239 * {@code Long.hashCode()}.
1240 *
1241 * @param value the value to hash
1242 * @return a hash code value for a {@code long} value.
1243 * @since 1.8
1244 */
1245 public static int hashCode(long value) {
1246 return (int)(value ^ (value >>> 32));
1247 }
1248
1249 /**
1250 * Compares this object to the specified object. The result is
1251 * {@code true} if and only if the argument is not
1252 * {@code null} and is a {@code Long} object that
1253 * contains the same {@code long} value as this object.
1254 *
1255 * @param obj the object to compare with.
1256 * @return {@code true} if the objects are the same;
1257 * {@code false} otherwise.
1258 */
1259 public boolean equals(Object obj) {
1260 if (obj instanceof Long ell) {
1261 return value == ell.longValue();
1262 }
1263 return false;
1264 }
1265
1266 /**
1267 * Determines the {@code long} value of the system property
1268 * with the specified name.
1269 *
1270 * <p>The first argument is treated as the name of a system
1271 * property. System properties are accessible through the {@link
1272 * java.lang.System#getProperty(java.lang.String)} method. The
1273 * string value of this property is then interpreted as a {@code
1274 * long} value using the grammar supported by {@link Long#decode decode}
1275 * and a {@code Long} object representing this value is returned.
1276 *
1277 * <p>If there is no property with the specified name, if the
1278 * specified name is empty or {@code null}, or if the property
1279 * does not have the correct numeric format, then {@code null} is
1280 * returned.
1281 *
1282 * <p>In other words, this method returns a {@code Long} object
1283 * equal to the value of:
1284 *
1285 * <blockquote>
1286 * {@code getLong(nm, null)}
1287 * </blockquote>
1288 *
1289 * @param nm property name.
1290 * @return the {@code Long} value of the property.
1291 * @throws SecurityException for the same reasons as
1292 * {@link System#getProperty(String) System.getProperty}
1293 * @see java.lang.System#getProperty(java.lang.String)
1294 * @see java.lang.System#getProperty(java.lang.String, java.lang.String)
1295 */
1296 public static Long getLong(String nm) {
1297 return getLong(nm, null);
1298 }
1299
1300 /**
1301 * Determines the {@code long} value of the system property
1302 * with the specified name.
1303 *
1304 * <p>The first argument is treated as the name of a system
1305 * property. System properties are accessible through the {@link
1306 * java.lang.System#getProperty(java.lang.String)} method. The
1307 * string value of this property is then interpreted as a {@code
1308 * long} value using the grammar supported by {@link Long#decode decode}
1309 * and a {@code Long} object representing this value is returned.
1310 *
1311 * <p>The second argument is the default value. A {@code Long} object
1312 * that represents the value of the second argument is returned if there
1313 * is no property of the specified name, if the property does not have
1314 * the correct numeric format, or if the specified name is empty or null.
1315 *
1316 * <p>In other words, this method returns a {@code Long} object equal
1317 * to the value of:
1318 *
1319 * <blockquote>
1320 * {@code getLong(nm, Long.valueOf(val))}
1321 * </blockquote>
1322 *
1323 * but in practice it may be implemented in a manner such as:
1324 *
1325 * <blockquote><pre>
1326 * Long result = getLong(nm, null);
1327 * return (result == null) ? Long.valueOf(val) : result;
1328 * </pre></blockquote>
1329 *
1330 * to avoid the unnecessary allocation of a {@code Long} object when
1331 * the default value is not needed.
1332 *
1333 * @param nm property name.
1334 * @param val default value.
1335 * @return the {@code Long} value of the property.
1336 * @throws SecurityException for the same reasons as
1337 * {@link System#getProperty(String) System.getProperty}
1338 * @see java.lang.System#getProperty(java.lang.String)
1339 * @see java.lang.System#getProperty(java.lang.String, java.lang.String)
1340 */
1341 public static Long getLong(String nm, long val) {
1342 Long result = Long.getLong(nm, null);
1343 return (result == null) ? Long.valueOf(val) : result;
1344 }
1345
1346 /**
1347 * Returns the {@code long} value of the system property with
1348 * the specified name. The first argument is treated as the name
1349 * of a system property. System properties are accessible through
1350 * the {@link java.lang.System#getProperty(java.lang.String)}
1351 * method. The string value of this property is then interpreted
1352 * as a {@code long} value, as per the
1353 * {@link Long#decode decode} method, and a {@code Long} object
1354 * representing this value is returned; in summary:
1355 *
1356 * <ul>
1357 * <li>If the property value begins with the two ASCII characters
1358 * {@code 0x} or the ASCII character {@code #}, not followed by
1359 * a minus sign, then the rest of it is parsed as a hexadecimal integer
1360 * exactly as for the method {@link #valueOf(java.lang.String, int)}
1361 * with radix 16.
1362 * <li>If the property value begins with the ASCII character
1363 * {@code 0} followed by another character, it is parsed as
1364 * an octal integer exactly as by the method {@link
1365 * #valueOf(java.lang.String, int)} with radix 8.
1366 * <li>Otherwise the property value is parsed as a decimal
1367 * integer exactly as by the method
1368 * {@link #valueOf(java.lang.String, int)} with radix 10.
1369 * </ul>
1370 *
1371 * <p>Note that, in every case, neither {@code L}
1372 * ({@code '\u005Cu004C'}) nor {@code l}
1373 * ({@code '\u005Cu006C'}) is permitted to appear at the end
1374 * of the property value as a type indicator, as would be
1375 * permitted in Java programming language source code.
1376 *
1377 * <p>The second argument is the default value. The default value is
1378 * returned if there is no property of the specified name, if the
1379 * property does not have the correct numeric format, or if the
1380 * specified name is empty or {@code null}.
1381 *
1382 * @param nm property name.
1383 * @param val default value.
1384 * @return the {@code Long} value of the property.
1385 * @throws SecurityException for the same reasons as
1386 * {@link System#getProperty(String) System.getProperty}
1387 * @see System#getProperty(java.lang.String)
1388 * @see System#getProperty(java.lang.String, java.lang.String)
1389 */
1390 public static Long getLong(String nm, Long val) {
1391 String v = null;
1392 try {
1393 v = System.getProperty(nm);
1394 } catch (IllegalArgumentException | NullPointerException e) {
1395 }
1396 if (v != null) {
1397 try {
1398 return Long.decode(v);
1399 } catch (NumberFormatException e) {
1400 }
1401 }
1402 return val;
1403 }
1404
1405 /**
1406 * Compares two {@code Long} objects numerically.
1407 *
1408 * @param anotherLong the {@code Long} to be compared.
1409 * @return the value {@code 0} if this {@code Long} is
1410 * equal to the argument {@code Long}; a value less than
1411 * {@code 0} if this {@code Long} is numerically less
1412 * than the argument {@code Long}; and a value greater
1413 * than {@code 0} if this {@code Long} is numerically
1414 * greater than the argument {@code Long} (signed
1415 * comparison).
1416 * @since 1.2
1417 */
1418 public int compareTo(Long anotherLong) {
1419 return compare(this.value, anotherLong.value);
1420 }
1421
1422 /**
1423 * Compares two {@code long} values numerically.
1424 * The value returned is identical to what would be returned by:
1425 * <pre>
1426 * Long.valueOf(x).compareTo(Long.valueOf(y))
1427 * </pre>
1428 *
1429 * @param x the first {@code long} to compare
1430 * @param y the second {@code long} to compare
1431 * @return the value {@code 0} if {@code x == y};
1432 * a value less than {@code 0} if {@code x < y}; and
1433 * a value greater than {@code 0} if {@code x > y}
1434 * @since 1.7
1435 */
1436 public static int compare(long x, long y) {
1437 return (x < y) ? -1 : ((x == y) ? 0 : 1);
1438 }
1439
1440 /**
1441 * Compares two {@code long} values numerically treating the values
1442 * as unsigned.
1443 *
1444 * @param x the first {@code long} to compare
1445 * @param y the second {@code long} to compare
1446 * @return the value {@code 0} if {@code x == y}; a value less
1447 * than {@code 0} if {@code x < y} as unsigned values; and
1448 * a value greater than {@code 0} if {@code x > y} as
1449 * unsigned values
1450 * @since 1.8
1451 */
1452 @IntrinsicCandidate
1453 public static int compareUnsigned(long x, long y) {
1454 return compare(x + MIN_VALUE, y + MIN_VALUE);
1455 }
1456
1457
1458 /**
1459 * Returns the unsigned quotient of dividing the first argument by
1460 * the second where each argument and the result is interpreted as
1461 * an unsigned value.
1462 *
1463 * <p>Note that in two's complement arithmetic, the three other
1464 * basic arithmetic operations of add, subtract, and multiply are
1465 * bit-wise identical if the two operands are regarded as both
1466 * being signed or both being unsigned. Therefore separate {@code
1467 * addUnsigned}, etc. methods are not provided.
1468 *
1469 * @param dividend the value to be divided
1470 * @param divisor the value doing the dividing
1471 * @return the unsigned quotient of the first argument divided by
1472 * the second argument
1473 * @see #remainderUnsigned
1474 * @since 1.8
1475 */
1476 @IntrinsicCandidate
1477 public static long divideUnsigned(long dividend, long divisor) {
1478 /* See Hacker's Delight (2nd ed), section 9.3 */
1479 if (divisor >= 0) {
1480 final long q = (dividend >>> 1) / divisor << 1;
1481 final long r = dividend - q * divisor;
1482 return q + ((r | ~(r - divisor)) >>> (Long.SIZE - 1));
1483 }
1484 return (dividend & ~(dividend - divisor)) >>> (Long.SIZE - 1);
1485 }
1486
1487 /**
1488 * Returns the unsigned remainder from dividing the first argument
1489 * by the second where each argument and the result is interpreted
1490 * as an unsigned value.
1491 *
1492 * @param dividend the value to be divided
1493 * @param divisor the value doing the dividing
1494 * @return the unsigned remainder of the first argument divided by
1495 * the second argument
1496 * @see #divideUnsigned
1497 * @since 1.8
1498 */
1499 @IntrinsicCandidate
1500 public static long remainderUnsigned(long dividend, long divisor) {
1501 /* See Hacker's Delight (2nd ed), section 9.3 */
1502 if (divisor >= 0) {
1503 final long q = (dividend >>> 1) / divisor << 1;
1504 final long r = dividend - q * divisor;
1505 /*
1506 * Here, 0 <= r < 2 * divisor
1507 * (1) When 0 <= r < divisor, the remainder is simply r.
1508 * (2) Otherwise the remainder is r - divisor.
1509 *
1510 * In case (1), r - divisor < 0. Applying ~ produces a long with
1511 * sign bit 0, so >> produces 0. The returned value is thus r.
1512 *
1513 * In case (2), a similar reasoning shows that >> produces -1,
1514 * so the returned value is r - divisor.
1515 */
1516 return r - ((~(r - divisor) >> (Long.SIZE - 1)) & divisor);
1517 }
1518 /*
1519 * (1) When dividend >= 0, the remainder is dividend.
1520 * (2) Otherwise
1521 * (2.1) When dividend < divisor, the remainder is dividend.
1522 * (2.2) Otherwise the remainder is dividend - divisor
1523 *
1524 * A reasoning similar to the above shows that the returned value
1525 * is as expected.
1526 */
1527 return dividend - (((dividend & ~(dividend - divisor)) >> (Long.SIZE - 1)) & divisor);
1528 }
1529
1530 // Bit Twiddling
1531
1532 /**
1533 * The number of bits used to represent a {@code long} value in two's
1534 * complement binary form.
1535 *
1536 * @since 1.5
1537 */
1538 @Native public static final int SIZE = 64;
1539
1540 /**
1541 * The number of bytes used to represent a {@code long} value in two's
1542 * complement binary form.
1543 *
1544 * @since 1.8
1545 */
1546 public static final int BYTES = SIZE / Byte.SIZE;
1547
1548 /**
1549 * Returns a {@code long} value with at most a single one-bit, in the
1550 * position of the highest-order ("leftmost") one-bit in the specified
1551 * {@code long} value. Returns zero if the specified value has no
1552 * one-bits in its two's complement binary representation, that is, if it
1553 * is equal to zero.
1554 *
1555 * @param i the value whose highest one bit is to be computed
1556 * @return a {@code long} value with a single one-bit, in the position
1557 * of the highest-order one-bit in the specified value, or zero if
1558 * the specified value is itself equal to zero.
1559 * @since 1.5
1560 */
1561 public static long highestOneBit(long i) {
1562 return i & (MIN_VALUE >>> numberOfLeadingZeros(i));
1563 }
1564
1565 /**
1566 * Returns a {@code long} value with at most a single one-bit, in the
1567 * position of the lowest-order ("rightmost") one-bit in the specified
1568 * {@code long} value. Returns zero if the specified value has no
1569 * one-bits in its two's complement binary representation, that is, if it
1570 * is equal to zero.
1571 *
1572 * @param i the value whose lowest one bit is to be computed
1573 * @return a {@code long} value with a single one-bit, in the position
1574 * of the lowest-order one-bit in the specified value, or zero if
1575 * the specified value is itself equal to zero.
1576 * @since 1.5
1577 */
1578 public static long lowestOneBit(long i) {
1579 // HD, Section 2-1
1580 return i & -i;
1581 }
1582
1583 /**
1584 * Returns the number of zero bits preceding the highest-order
1585 * ("leftmost") one-bit in the two's complement binary representation
1586 * of the specified {@code long} value. Returns 64 if the
1587 * specified value has no one-bits in its two's complement representation,
1588 * in other words if it is equal to zero.
1589 *
1590 * <p>Note that this method is closely related to the logarithm base 2.
1591 * For all positive {@code long} values x:
1592 * <ul>
1593 * <li>floor(log<sub>2</sub>(x)) = {@code 63 - numberOfLeadingZeros(x)}
1594 * <li>ceil(log<sub>2</sub>(x)) = {@code 64 - numberOfLeadingZeros(x - 1)}
1595 * </ul>
1596 *
1597 * @param i the value whose number of leading zeros is to be computed
1598 * @return the number of zero bits preceding the highest-order
1599 * ("leftmost") one-bit in the two's complement binary representation
1600 * of the specified {@code long} value, or 64 if the value
1601 * is equal to zero.
1602 * @since 1.5
1603 */
1604 @IntrinsicCandidate
1605 public static int numberOfLeadingZeros(long i) {
1606 int x = (int)(i >>> 32);
1607 return x == 0 ? 32 + Integer.numberOfLeadingZeros((int)i)
1608 : Integer.numberOfLeadingZeros(x);
1609 }
1610
1611 /**
1612 * Returns the number of zero bits following the lowest-order ("rightmost")
1613 * one-bit in the two's complement binary representation of the specified
1614 * {@code long} value. Returns 64 if the specified value has no
1615 * one-bits in its two's complement representation, in other words if it is
1616 * equal to zero.
1617 *
1618 * @param i the value whose number of trailing zeros is to be computed
1619 * @return the number of zero bits following the lowest-order ("rightmost")
1620 * one-bit in the two's complement binary representation of the
1621 * specified {@code long} value, or 64 if the value is equal
1622 * to zero.
1623 * @since 1.5
1624 */
1625 @IntrinsicCandidate
1626 public static int numberOfTrailingZeros(long i) {
1627 int x = (int)i;
1628 return x == 0 ? 32 + Integer.numberOfTrailingZeros((int)(i >>> 32))
1629 : Integer.numberOfTrailingZeros(x);
1630 }
1631
1632 /**
1633 * Returns the number of one-bits in the two's complement binary
1634 * representation of the specified {@code long} value. This function is
1635 * sometimes referred to as the <i>population count</i>.
1636 *
1637 * @param i the value whose bits are to be counted
1638 * @return the number of one-bits in the two's complement binary
1639 * representation of the specified {@code long} value.
1640 * @since 1.5
1641 */
1642 @IntrinsicCandidate
1643 public static int bitCount(long i) {
1644 // HD, Figure 5-2
1645 i = i - ((i >>> 1) & 0x5555555555555555L);
1646 i = (i & 0x3333333333333333L) + ((i >>> 2) & 0x3333333333333333L);
1647 i = (i + (i >>> 4)) & 0x0f0f0f0f0f0f0f0fL;
1648 i = i + (i >>> 8);
1649 i = i + (i >>> 16);
1650 i = i + (i >>> 32);
1651 return (int)i & 0x7f;
1652 }
1653
1654 /**
1655 * Returns the value obtained by rotating the two's complement binary
1656 * representation of the specified {@code long} value left by the
1657 * specified number of bits. (Bits shifted out of the left hand, or
1658 * high-order, side reenter on the right, or low-order.)
1659 *
1660 * <p>Note that left rotation with a negative distance is equivalent to
1661 * right rotation: {@code rotateLeft(val, -distance) == rotateRight(val,
1662 * distance)}. Note also that rotation by any multiple of 64 is a
1663 * no-op, so all but the last six bits of the rotation distance can be
1664 * ignored, even if the distance is negative: {@code rotateLeft(val,
1665 * distance) == rotateLeft(val, distance & 0x3F)}.
1666 *
1667 * @param i the value whose bits are to be rotated left
1668 * @param distance the number of bit positions to rotate left
1669 * @return the value obtained by rotating the two's complement binary
1670 * representation of the specified {@code long} value left by the
1671 * specified number of bits.
1672 * @since 1.5
1673 */
1674 public static long rotateLeft(long i, int distance) {
1675 return (i << distance) | (i >>> -distance);
1676 }
1677
1678 /**
1679 * Returns the value obtained by rotating the two's complement binary
1680 * representation of the specified {@code long} value right by the
1681 * specified number of bits. (Bits shifted out of the right hand, or
1682 * low-order, side reenter on the left, or high-order.)
1683 *
1684 * <p>Note that right rotation with a negative distance is equivalent to
1685 * left rotation: {@code rotateRight(val, -distance) == rotateLeft(val,
1686 * distance)}. Note also that rotation by any multiple of 64 is a
1687 * no-op, so all but the last six bits of the rotation distance can be
1688 * ignored, even if the distance is negative: {@code rotateRight(val,
1689 * distance) == rotateRight(val, distance & 0x3F)}.
1690 *
1691 * @param i the value whose bits are to be rotated right
1692 * @param distance the number of bit positions to rotate right
1693 * @return the value obtained by rotating the two's complement binary
1694 * representation of the specified {@code long} value right by the
1695 * specified number of bits.
1696 * @since 1.5
1697 */
1698 public static long rotateRight(long i, int distance) {
1699 return (i >>> distance) | (i << -distance);
1700 }
1701
1702 /**
1703 * Returns the value obtained by reversing the order of the bits in the
1704 * two's complement binary representation of the specified {@code long}
1705 * value.
1706 *
1707 * @param i the value to be reversed
1708 * @return the value obtained by reversing order of the bits in the
1709 * specified {@code long} value.
1710 * @since 1.5
1711 */
1712 @IntrinsicCandidate
1713 public static long reverse(long i) {
1714 // HD, Figure 7-1
1715 i = (i & 0x5555555555555555L) << 1 | (i >>> 1) & 0x5555555555555555L;
1716 i = (i & 0x3333333333333333L) << 2 | (i >>> 2) & 0x3333333333333333L;
1717 i = (i & 0x0f0f0f0f0f0f0f0fL) << 4 | (i >>> 4) & 0x0f0f0f0f0f0f0f0fL;
1718
1719 return reverseBytes(i);
1720 }
1721
1722 /**
1723 * Returns the value obtained by compressing the bits of the
1724 * specified {@code long} value, {@code i}, in accordance with
1725 * the specified bit mask.
1726 * <p>
1727 * For each one-bit value {@code mb} of the mask, from least
1728 * significant to most significant, the bit value of {@code i} at
1729 * the same bit location as {@code mb} is assigned to the compressed
1730 * value contiguously starting from the least significant bit location.
1731 * All the upper remaining bits of the compressed value are set
1732 * to zero.
1733 *
1734 * @apiNote
1735 * Consider the simple case of compressing the digits of a hexadecimal
1736 * value:
1737 * {@snippet lang="java" :
1738 * // Compressing drink to food
1739 * compress(0xCAFEBABEL, 0xFF00FFF0L) == 0xCABABL
1740 * }
1741 * Starting from the least significant hexadecimal digit at position 0
1742 * from the right, the mask {@code 0xFF00FFF0} selects hexadecimal digits
1743 * at positions 1, 2, 3, 6 and 7 of {@code 0xCAFEBABE}. The selected digits
1744 * occur in the resulting compressed value contiguously from digit position
1745 * 0 in the same order.
1746 * <p>
1747 * The following identities all return {@code true} and are helpful to
1748 * understand the behaviour of {@code compress}:
1749 * {@snippet lang="java" :
1750 * // Returns 1 if the bit at position n is one
1751 * compress(x, 1L << n) == (x >> n & 1)
1752 *
1753 * // Logical shift right
1754 * compress(x, -1L << n) == x >>> n
1755 *
1756 * // Any bits not covered by the mask are ignored
1757 * compress(x, m) == compress(x & m, m)
1758 *
1759 * // Compressing a value by itself
1760 * compress(m, m) == (m == -1 || m == 0) ? m : (1L << bitCount(m)) - 1
1761 *
1762 * // Expanding then compressing with the same mask
1763 * compress(expand(x, m), m) == x & compress(m, m)
1764 * }
1765 * <p>
1766 * The Sheep And Goats (SAG) operation (see Hacker's Delight, Second Edition, section 7.7)
1767 * can be implemented as follows:
1768 * {@snippet lang="java" :
1769 * long compressLeft(long i, long mask) {
1770 * // This implementation follows the description in Hacker's Delight which
1771 * // is informative. A more optimal implementation is:
1772 * // Long.compress(i, mask) << -Long.bitCount(mask)
1773 * return Long.reverse(
1774 * Long.compress(Long.reverse(i), Long.reverse(mask)));
1775 * }
1776 *
1777 * long sag(long i, long mask) {
1778 * return compressLeft(i, mask) | Long.compress(i, ~mask);
1779 * }
1780 *
1781 * // Separate the sheep from the goats
1782 * sag(0x00000000_CAFEBABEL, 0xFFFFFFFF_FF00FFF0L) == 0x00000000_CABABFEEL
1783 * }
1784 *
1785 * @param i the value whose bits are to be compressed
1786 * @param mask the bit mask
1787 * @return the compressed value
1788 * @see #expand
1789 * @since 19
1790 */
1791 @IntrinsicCandidate
1792 public static long compress(long i, long mask) {
1793 // See Hacker's Delight (2nd ed) section 7.4 Compress, or Generalized Extract
1794
1795 i = i & mask; // Clear irrelevant bits
1796 long maskCount = ~mask << 1; // Count 0's to right
1797
1798 for (int j = 0; j < 6; j++) {
1799 // Parallel prefix
1800 // Mask prefix identifies bits of the mask that have an odd number of 0's to the right
1801 long maskPrefix = parallelSuffix(maskCount);
1802 // Bits to move
1803 long maskMove = maskPrefix & mask;
1804 // Compress mask
1805 mask = (mask ^ maskMove) | (maskMove >>> (1 << j));
1806 // Bits of i to be moved
1807 long t = i & maskMove;
1808 // Compress i
1809 i = (i ^ t) | (t >>> (1 << j));
1810 // Adjust the mask count by identifying bits that have 0 to the right
1811 maskCount = maskCount & ~maskPrefix;
1812 }
1813 return i;
1814 }
1815
1816 /**
1817 * Returns the value obtained by expanding the bits of the
1818 * specified {@code long} value, {@code i}, in accordance with
1819 * the specified bit mask.
1820 * <p>
1821 * For each one-bit value {@code mb} of the mask, from least
1822 * significant to most significant, the next contiguous bit value
1823 * of {@code i} starting at the least significant bit is assigned
1824 * to the expanded value at the same bit location as {@code mb}.
1825 * All other remaining bits of the expanded value are set to zero.
1826 *
1827 * @apiNote
1828 * Consider the simple case of expanding the digits of a hexadecimal
1829 * value:
1830 * {@snippet lang="java" :
1831 * expand(0x0000CABABL, 0xFF00FFF0L) == 0xCA00BAB0L
1832 * }
1833 * Starting from the least significant hexadecimal digit at position 0
1834 * from the right, the mask {@code 0xFF00FFF0} selects the first five
1835 * hexadecimal digits of {@code 0x0000CABAB}. The selected digits occur
1836 * in the resulting expanded value in order at positions 1, 2, 3, 6, and 7.
1837 * <p>
1838 * The following identities all return {@code true} and are helpful to
1839 * understand the behaviour of {@code expand}:
1840 * {@snippet lang="java" :
1841 * // Logically shift right the bit at position 0
1842 * expand(x, 1L << n) == (x & 1) << n
1843 *
1844 * // Logically shift right
1845 * expand(x, -1L << n) == x << n
1846 *
1847 * // Expanding all bits returns the mask
1848 * expand(-1L, m) == m
1849 *
1850 * // Any bits not covered by the mask are ignored
1851 * expand(x, m) == expand(x, m) & m
1852 *
1853 * // Compressing then expanding with the same mask
1854 * expand(compress(x, m), m) == x & m
1855 * }
1856 * <p>
1857 * The select operation for determining the position of the one-bit with
1858 * index {@code n} in a {@code long} value can be implemented as follows:
1859 * {@snippet lang="java" :
1860 * long select(long i, long n) {
1861 * // the one-bit in i (the mask) with index n
1862 * long nthBit = Long.expand(1L << n, i);
1863 * // the bit position of the one-bit with index n
1864 * return Long.numberOfTrailingZeros(nthBit);
1865 * }
1866 *
1867 * // The one-bit with index 0 is at bit position 1
1868 * select(0b10101010_10101010, 0) == 1
1869 * // The one-bit with index 3 is at bit position 7
1870 * select(0b10101010_10101010, 3) == 7
1871 * }
1872 *
1873 * @param i the value whose bits are to be expanded
1874 * @param mask the bit mask
1875 * @return the expanded value
1876 * @see #compress
1877 * @since 19
1878 */
1879 @IntrinsicCandidate
1880 public static long expand(long i, long mask) {
1881 // Save original mask
1882 long originalMask = mask;
1883 // Count 0's to right
1884 long maskCount = ~mask << 1;
1885 long maskPrefix = parallelSuffix(maskCount);
1886 // Bits to move
1887 long maskMove1 = maskPrefix & mask;
1888 // Compress mask
1889 mask = (mask ^ maskMove1) | (maskMove1 >>> (1 << 0));
1890 maskCount = maskCount & ~maskPrefix;
1891
1892 maskPrefix = parallelSuffix(maskCount);
1893 // Bits to move
1894 long maskMove2 = maskPrefix & mask;
1895 // Compress mask
1896 mask = (mask ^ maskMove2) | (maskMove2 >>> (1 << 1));
1897 maskCount = maskCount & ~maskPrefix;
1898
1899 maskPrefix = parallelSuffix(maskCount);
1900 // Bits to move
1901 long maskMove3 = maskPrefix & mask;
1902 // Compress mask
1903 mask = (mask ^ maskMove3) | (maskMove3 >>> (1 << 2));
1904 maskCount = maskCount & ~maskPrefix;
1905
1906 maskPrefix = parallelSuffix(maskCount);
1907 // Bits to move
1908 long maskMove4 = maskPrefix & mask;
1909 // Compress mask
1910 mask = (mask ^ maskMove4) | (maskMove4 >>> (1 << 3));
1911 maskCount = maskCount & ~maskPrefix;
1912
1913 maskPrefix = parallelSuffix(maskCount);
1914 // Bits to move
1915 long maskMove5 = maskPrefix & mask;
1916 // Compress mask
1917 mask = (mask ^ maskMove5) | (maskMove5 >>> (1 << 4));
1918 maskCount = maskCount & ~maskPrefix;
1919
1920 maskPrefix = parallelSuffix(maskCount);
1921 // Bits to move
1922 long maskMove6 = maskPrefix & mask;
1923
1924 long t = i << (1 << 5);
1925 i = (i & ~maskMove6) | (t & maskMove6);
1926 t = i << (1 << 4);
1927 i = (i & ~maskMove5) | (t & maskMove5);
1928 t = i << (1 << 3);
1929 i = (i & ~maskMove4) | (t & maskMove4);
1930 t = i << (1 << 2);
1931 i = (i & ~maskMove3) | (t & maskMove3);
1932 t = i << (1 << 1);
1933 i = (i & ~maskMove2) | (t & maskMove2);
1934 t = i << (1 << 0);
1935 i = (i & ~maskMove1) | (t & maskMove1);
1936
1937 // Clear irrelevant bits
1938 return i & originalMask;
1939 }
1940
1941 @ForceInline
1942 private static long parallelSuffix(long maskCount) {
1943 long maskPrefix = maskCount ^ (maskCount << 1);
1944 maskPrefix = maskPrefix ^ (maskPrefix << 2);
1945 maskPrefix = maskPrefix ^ (maskPrefix << 4);
1946 maskPrefix = maskPrefix ^ (maskPrefix << 8);
1947 maskPrefix = maskPrefix ^ (maskPrefix << 16);
1948 maskPrefix = maskPrefix ^ (maskPrefix << 32);
1949 return maskPrefix;
1950 }
1951
1952 /**
1953 * Returns the signum function of the specified {@code long} value. (The
1954 * return value is -1 if the specified value is negative; 0 if the
1955 * specified value is zero; and 1 if the specified value is positive.)
1956 *
1957 * @param i the value whose signum is to be computed
1958 * @return the signum function of the specified {@code long} value.
1959 * @since 1.5
1960 */
1961 public static int signum(long i) {
1962 // HD, Section 2-7
1963 return (int) ((i >> 63) | (-i >>> 63));
1964 }
1965
1966 /**
1967 * Returns the value obtained by reversing the order of the bytes in the
1968 * two's complement representation of the specified {@code long} value.
1969 *
1970 * @param i the value whose bytes are to be reversed
1971 * @return the value obtained by reversing the bytes in the specified
1972 * {@code long} value.
1973 * @since 1.5
1974 */
1975 @IntrinsicCandidate
1976 public static long reverseBytes(long i) {
1977 i = (i & 0x00ff00ff00ff00ffL) << 8 | (i >>> 8) & 0x00ff00ff00ff00ffL;
1978 return (i << 48) | ((i & 0xffff0000L) << 16) |
1979 ((i >>> 16) & 0xffff0000L) | (i >>> 48);
1980 }
1981
1982 /**
1983 * Adds two {@code long} values together as per the + operator.
1984 *
1985 * @param a the first operand
1986 * @param b the second operand
1987 * @return the sum of {@code a} and {@code b}
1988 * @see java.util.function.BinaryOperator
1989 * @since 1.8
1990 */
1991 public static long sum(long a, long b) {
1992 return a + b;
1993 }
1994
1995 /**
1996 * Returns the greater of two {@code long} values
1997 * as if by calling {@link Math#max(long, long) Math.max}.
1998 *
1999 * @param a the first operand
2000 * @param b the second operand
2001 * @return the greater of {@code a} and {@code b}
2002 * @see java.util.function.BinaryOperator
2003 * @since 1.8
2004 */
2005 public static long max(long a, long b) {
2006 return Math.max(a, b);
2007 }
2008
2009 /**
2010 * Returns the smaller of two {@code long} values
2011 * as if by calling {@link Math#min(long, long) Math.min}.
2012 *
2013 * @param a the first operand
2014 * @param b the second operand
2015 * @return the smaller of {@code a} and {@code b}
2016 * @see java.util.function.BinaryOperator
2017 * @since 1.8
2018 */
2019 public static long min(long a, long b) {
2020 return Math.min(a, b);
2021 }
2022
2023 /**
2024 * Returns an {@link Optional} containing the nominal descriptor for this
2025 * instance, which is the instance itself.
2026 *
2027 * @return an {@link Optional} describing the {@linkplain Long} instance
2028 * @since 12
2029 */
2030 @Override
2031 public Optional<Long> describeConstable() {
2032 return Optional.of(this);
2033 }
2034
2035 /**
2036 * Resolves this instance as a {@link ConstantDesc}, the result of which is
2037 * the instance itself.
2038 *
2039 * @param lookup ignored
2040 * @return the {@linkplain Long} instance
2041 * @since 12
2042 */
2043 @Override
2044 public Long resolveConstantDesc(MethodHandles.Lookup lookup) {
2045 return this;
2046 }
2047
2048 /** use serialVersionUID from JDK 1.0.2 for interoperability */
2049 @java.io.Serial
2050 @Native private static final long serialVersionUID = 4290774380558885855L;
2051 }