1 /*
2 * Copyright (c) 1994, 2023, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 package java.lang;
27
28 import java.lang.annotation.Native;
29 import java.lang.invoke.MethodHandles;
30 import java.lang.constant.Constable;
31 import java.lang.constant.ConstantDesc;
32 import java.math.*;
33 import java.util.Objects;
34 import java.util.Optional;
35
36 import jdk.internal.misc.CDS;
37 import jdk.internal.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 wraps a value of the primitive type {@code
50 * long} in an object. An object of type {@code Long} contains a
51 * single field whose type is {@code long}.
52 *
53 * <p> In addition, this class provides several methods for converting
54 * a {@code long} to a {@code String} and a {@code String} to a {@code
55 * long}, as well as other constants and methods useful when dealing
56 * with a {@code long}.
57 *
58 * <p>This is a <a href="{@docRoot}/java.base/java/lang/doc-files/ValueBased.html">value-based</a>
59 * class; programmers should treat instances that are
60 * {@linkplain #equals(Object) equal} as interchangeable and should not
61 * use instances for synchronization, or unpredictable behavior may
62 * occur. For example, in a future release, synchronization may fail.
63 *
64 * <p>Implementation note: The implementations of the "bit twiddling"
65 * methods (such as {@link #highestOneBit(long) highestOneBit} and
66 * {@link #numberOfTrailingZeros(long) numberOfTrailingZeros}) are
67 * based on material from Henry S. Warren, Jr.'s <i>Hacker's
68 * Delight</i>, (Addison Wesley, 2002).
69 *
70 * @author Lee Boynton
71 * @author Arthur van Hoff
72 * @author Josh Bloch
73 * @author Joseph D. Darcy
74 * @since 1.0
75 */
76 @jdk.internal.MigratedValueClass
77 @jdk.internal.ValueBased
78 public final class Long extends Number
79 implements Comparable<Long>, Constable, ConstantDesc {
80 /**
81 * A constant holding the minimum value a {@code long} can
82 * have, -2<sup>63</sup>.
83 */
84 @Native public static final long MIN_VALUE = 0x8000000000000000L;
85
86 /**
87 * A constant holding the maximum value a {@code long} can
88 * have, 2<sup>63</sup>-1.
89 */
90 @Native public static final long MAX_VALUE = 0x7fffffffffffffffL;
91
92 /**
93 * The {@code Class} instance representing the primitive type
94 * {@code long}.
95 *
96 * @since 1.1
97 */
98 @SuppressWarnings("unchecked")
99 public static final Class<Long> TYPE = (Class<Long>) Class.getPrimitiveClass("long");
100
101 /**
102 * Returns a string representation of the first argument in the
103 * radix specified by the second argument.
104 *
105 * <p>If the radix is smaller than {@code Character.MIN_RADIX}
106 * or larger than {@code Character.MAX_RADIX}, then the radix
107 * {@code 10} is used instead.
108 *
109 * <p>If the first argument is negative, the first element of the
110 * result is the ASCII minus sign {@code '-'}
111 * ({@code '\u005Cu002d'}). If the first argument is not
112 * negative, no sign character appears in the result.
113 *
114 * <p>The remaining characters of the result represent the magnitude
115 * of the first argument. If the magnitude is zero, it is
116 * represented by a single zero character {@code '0'}
117 * ({@code '\u005Cu0030'}); otherwise, the first character of
118 * the representation of the magnitude will not be the zero
119 * character. The following ASCII characters are used as digits:
120 *
121 * <blockquote>
122 * {@code 0123456789abcdefghijklmnopqrstuvwxyz}
123 * </blockquote>
124 *
125 * These are {@code '\u005Cu0030'} through
126 * {@code '\u005Cu0039'} and {@code '\u005Cu0061'} through
127 * {@code '\u005Cu007a'}. If {@code radix} is
128 * <var>N</var>, then the first <var>N</var> of these characters
129 * are used as radix-<var>N</var> digits in the order shown. Thus,
130 * the digits for hexadecimal (radix 16) are
131 * {@code 0123456789abcdef}. If uppercase letters are
132 * desired, the {@link java.lang.String#toUpperCase()} method may
133 * be called on the result:
134 *
135 * <blockquote>
136 * {@code Long.toString(n, 16).toUpperCase()}
137 * </blockquote>
138 *
139 * @param i a {@code long} to be converted to a string.
140 * @param radix the radix to use in the string representation.
141 * @return a string representation of the argument in the specified radix.
142 * @see java.lang.Character#MAX_RADIX
143 * @see java.lang.Character#MIN_RADIX
144 */
145 public static String toString(long i, int radix) {
146 if (radix < Character.MIN_RADIX || radix > Character.MAX_RADIX)
147 radix = 10;
148 if (radix == 10)
149 return toString(i);
150
151 if (COMPACT_STRINGS) {
152 byte[] buf = new byte[65];
153 int charPos = 64;
154 boolean negative = (i < 0);
155
156 if (!negative) {
157 i = -i;
158 }
159
160 while (i <= -radix) {
161 buf[charPos--] = (byte)Integer.digits[(int)(-(i % radix))];
162 i = i / radix;
163 }
164 buf[charPos] = (byte)Integer.digits[(int)(-i)];
165
166 if (negative) {
167 buf[--charPos] = '-';
168 }
169 return StringLatin1.newString(buf, charPos, (65 - charPos));
170 }
171 return toStringUTF16(i, radix);
172 }
173
174 private static String toStringUTF16(long i, int radix) {
175 byte[] buf = new byte[65 * 2];
176 int charPos = 64;
177 boolean negative = (i < 0);
178 if (!negative) {
179 i = -i;
180 }
181 while (i <= -radix) {
182 StringUTF16.putChar(buf, charPos--, Integer.digits[(int)(-(i % radix))]);
183 i = i / radix;
184 }
185 StringUTF16.putChar(buf, charPos, Integer.digits[(int)(-i)]);
186 if (negative) {
187 StringUTF16.putChar(buf, --charPos, '-');
188 }
189 return StringUTF16.newString(buf, charPos, (65 - charPos));
190 }
191
192 /**
193 * Returns a string representation of the first argument as an
194 * unsigned integer value in the radix specified by the second
195 * argument.
196 *
197 * <p>If the radix is smaller than {@code Character.MIN_RADIX}
198 * or larger than {@code Character.MAX_RADIX}, then the radix
199 * {@code 10} is used instead.
200 *
201 * <p>Note that since the first argument is treated as an unsigned
202 * value, no leading sign character is printed.
203 *
204 * <p>If the magnitude is zero, it is represented by a single zero
205 * character {@code '0'} ({@code '\u005Cu0030'}); otherwise,
206 * the first character of the representation of the magnitude will
207 * not be the zero character.
208 *
209 * <p>The behavior of radixes and the characters used as digits
210 * are the same as {@link #toString(long, int) toString}.
211 *
212 * @param i an integer to be converted to an unsigned string.
213 * @param radix the radix to use in the string representation.
214 * @return an unsigned string representation of the argument in the specified radix.
215 * @see #toString(long, int)
216 * @since 1.8
217 */
218 public static String toUnsignedString(long i, int radix) {
219 if (i >= 0)
220 return toString(i, radix);
221 else {
222 return switch (radix) {
223 case 2 -> toBinaryString(i);
224 case 4 -> toUnsignedString0(i, 2);
225 case 8 -> toOctalString(i);
226 case 10 -> {
227 /*
228 * We can get the effect of an unsigned division by 10
229 * on a long value by first shifting right, yielding a
230 * positive value, and then dividing by 5. This
231 * allows the last digit and preceding digits to be
232 * isolated more quickly than by an initial conversion
233 * to BigInteger.
234 */
235 long quot = (i >>> 1) / 5;
236 long rem = i - quot * 10;
237 yield toString(quot) + rem;
238 }
239 case 16 -> toHexString(i);
240 case 32 -> toUnsignedString0(i, 5);
241 default -> toUnsignedBigInteger(i).toString(radix);
242 };
243 }
244 }
245
246 /**
247 * Return a BigInteger equal to the unsigned value of the
248 * argument.
249 */
250 private static BigInteger toUnsignedBigInteger(long i) {
251 if (i >= 0L)
252 return BigInteger.valueOf(i);
253 else {
254 int upper = (int) (i >>> 32);
255 int lower = (int) i;
256
257 // return (upper << 32) + lower
258 return (BigInteger.valueOf(Integer.toUnsignedLong(upper))).shiftLeft(32).
259 add(BigInteger.valueOf(Integer.toUnsignedLong(lower)));
260 }
261 }
262
263 /**
264 * Returns a string representation of the {@code long}
265 * argument as an unsigned integer in base 16.
266 *
267 * <p>The unsigned {@code long} value is the argument plus
268 * 2<sup>64</sup> if the argument is negative; otherwise, it is
269 * equal to the argument. This value is converted to a string of
270 * ASCII digits in hexadecimal (base 16) with no extra
271 * leading {@code 0}s.
272 *
273 * <p>The value of the argument can be recovered from the returned
274 * string {@code s} by calling {@link
275 * Long#parseUnsignedLong(String, int) Long.parseUnsignedLong(s,
276 * 16)}.
277 *
278 * <p>If the unsigned magnitude is zero, it is represented by a
279 * single zero character {@code '0'} ({@code '\u005Cu0030'});
280 * otherwise, the first character of the representation of the
281 * unsigned magnitude will not be the zero character. The
282 * following characters are used as hexadecimal digits:
283 *
284 * <blockquote>
285 * {@code 0123456789abcdef}
286 * </blockquote>
287 *
288 * These are the characters {@code '\u005Cu0030'} through
289 * {@code '\u005Cu0039'} and {@code '\u005Cu0061'} through
290 * {@code '\u005Cu0066'}. If uppercase letters are desired,
291 * the {@link java.lang.String#toUpperCase()} method may be called
292 * on the result:
293 *
294 * <blockquote>
295 * {@code Long.toHexString(n).toUpperCase()}
296 * </blockquote>
297 *
298 * @apiNote
299 * The {@link java.util.HexFormat} class provides formatting and parsing
300 * of byte arrays and primitives to return a string or adding to an {@link Appendable}.
301 * {@code HexFormat} formats and parses uppercase or lowercase hexadecimal characters,
302 * with leading zeros and for byte arrays includes for each byte
303 * a delimiter, prefix, and suffix.
304 *
305 * @param i a {@code long} to be converted to a string.
306 * @return the string representation of the unsigned {@code long}
307 * value represented by the argument in hexadecimal
308 * (base 16).
309 * @see java.util.HexFormat
310 * @see #parseUnsignedLong(String, int)
311 * @see #toUnsignedString(long, int)
312 * @since 1.0.2
313 */
314 public static String toHexString(long i) {
315 return toUnsignedString0(i, 4);
316 }
317
318 /**
319 * Returns a string representation of the {@code long}
320 * argument as an unsigned integer in base 8.
321 *
322 * <p>The unsigned {@code long} value is the argument plus
323 * 2<sup>64</sup> if the argument is negative; otherwise, it is
324 * equal to the argument. This value is converted to a string of
325 * ASCII digits in octal (base 8) with no extra leading
326 * {@code 0}s.
327 *
328 * <p>The value of the argument can be recovered from the returned
329 * string {@code s} by calling {@link
330 * Long#parseUnsignedLong(String, int) Long.parseUnsignedLong(s,
331 * 8)}.
332 *
333 * <p>If the unsigned magnitude is zero, it is represented by a
334 * single zero character {@code '0'} ({@code '\u005Cu0030'});
335 * otherwise, the first character of the representation of the
336 * unsigned magnitude will not be the zero character. The
337 * following characters are used as octal digits:
338 *
339 * <blockquote>
340 * {@code 01234567}
341 * </blockquote>
342 *
343 * These are the characters {@code '\u005Cu0030'} through
344 * {@code '\u005Cu0037'}.
345 *
346 * @param i a {@code long} to be converted to a string.
347 * @return the string representation of the unsigned {@code long}
348 * value represented by the argument in octal (base 8).
349 * @see #parseUnsignedLong(String, int)
350 * @see #toUnsignedString(long, int)
351 * @since 1.0.2
352 */
353 public static String toOctalString(long i) {
354 return toUnsignedString0(i, 3);
355 }
356
357 /**
358 * Returns a string representation of the {@code long}
359 * argument as an unsigned integer in base 2.
360 *
361 * <p>The unsigned {@code long} value is the argument plus
362 * 2<sup>64</sup> if the argument is negative; otherwise, it is
363 * equal to the argument. This value is converted to a string of
364 * ASCII digits in binary (base 2) with no extra leading
365 * {@code 0}s.
366 *
367 * <p>The value of the argument can be recovered from the returned
368 * string {@code s} by calling {@link
369 * Long#parseUnsignedLong(String, int) Long.parseUnsignedLong(s,
370 * 2)}.
371 *
372 * <p>If the unsigned magnitude is zero, it is represented by a
373 * single zero character {@code '0'} ({@code '\u005Cu0030'});
374 * otherwise, the first character of the representation of the
375 * unsigned magnitude will not be the zero character. The
376 * characters {@code '0'} ({@code '\u005Cu0030'}) and {@code
377 * '1'} ({@code '\u005Cu0031'}) are used as binary digits.
378 *
379 * @param i a {@code long} to be converted to a string.
380 * @return the string representation of the unsigned {@code long}
381 * value represented by the argument in binary (base 2).
382 * @see #parseUnsignedLong(String, int)
383 * @see #toUnsignedString(long, int)
384 * @since 1.0.2
385 */
386 public static String toBinaryString(long i) {
387 return toUnsignedString0(i, 1);
388 }
389
390 /**
391 * Format a long (treated as unsigned) into a String.
392 * @param val the value to format
393 * @param shift the log2 of the base to format in (4 for hex, 3 for octal, 1 for binary)
394 */
395 static String toUnsignedString0(long val, int shift) {
396 // assert shift > 0 && shift <=5 : "Illegal shift value";
397 int mag = Long.SIZE - Long.numberOfLeadingZeros(val);
398 int chars = Math.max(((mag + (shift - 1)) / shift), 1);
399 if (COMPACT_STRINGS) {
400 byte[] buf = new byte[chars];
401 formatUnsignedLong0(val, shift, buf, 0, chars);
402 return new String(buf, LATIN1);
403 } else {
404 byte[] buf = new byte[chars * 2];
405 formatUnsignedLong0UTF16(val, shift, buf, 0, chars);
406 return new String(buf, UTF16);
407 }
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] = (byte)Integer.digits[((int) val) & mask];
427 val >>>= shift;
428 } while (charPos > offset);
429 }
430
431 /**
432 * Format a long (treated as unsigned) into a byte buffer (UTF16 version). If
433 * {@code len} exceeds the formatted ASCII representation of {@code val},
434 * {@code buf} will be padded with leading zeroes.
435 *
436 * @param val the unsigned long to format
437 * @param shift the log2 of the base to format in (4 for hex, 3 for octal, 1 for binary)
438 * @param buf the byte buffer to write to
439 * @param offset the offset in the destination buffer to start at
440 * @param len the number of characters to write
441 */
442 private static void formatUnsignedLong0UTF16(long val, int shift, byte[] buf, int offset, int len) {
443 int charPos = offset + len;
444 int radix = 1 << shift;
445 int mask = radix - 1;
446 do {
447 StringUTF16.putChar(buf, --charPos, Integer.digits[((int) val) & mask]);
448 val >>>= shift;
449 } while (charPos > offset);
450 }
451
452 /**
453 * Returns a {@code String} object representing the specified
454 * {@code long}. The argument is converted to signed decimal
455 * representation and returned as a string, exactly as if the
456 * argument and the radix 10 were given as arguments to the {@link
457 * #toString(long, int)} method.
458 *
459 * @param i a {@code long} to be converted.
460 * @return a string representation of the argument in base 10.
461 */
462 public static String toString(long i) {
463 int size = DecimalDigits.stringSize(i);
464 if (COMPACT_STRINGS) {
465 byte[] buf = new byte[size];
466 StringLatin1.getChars(i, size, buf);
467 return new String(buf, LATIN1);
468 } else {
469 byte[] buf = new byte[size * 2];
470 StringUTF16.getChars(i, size, buf);
471 return new String(buf, UTF16);
472 }
473 }
474
475 /**
476 * Returns a string representation of the argument as an unsigned
477 * decimal value.
478 *
479 * The argument is converted to unsigned decimal representation
480 * and returned as a string exactly as if the argument and radix
481 * 10 were given as arguments to the {@link #toUnsignedString(long,
482 * int)} method.
483 *
484 * @param i an integer to be converted to an unsigned string.
485 * @return an unsigned string representation of the argument.
486 * @see #toUnsignedString(long, int)
487 * @since 1.8
488 */
489 public static String toUnsignedString(long i) {
490 return toUnsignedString(i, 10);
491 }
492
493 /**
494 * Parses the string argument as a signed {@code long} in the
495 * radix specified by the second argument. The characters in the
496 * string must all be digits of the specified radix (as determined
497 * by whether {@link java.lang.Character#digit(char, int)} returns
498 * a nonnegative value), except that the first character may be an
499 * ASCII minus sign {@code '-'} ({@code '\u005Cu002D'}) to
500 * indicate a negative value or an ASCII plus sign {@code '+'}
501 * ({@code '\u005Cu002B'}) to indicate a positive value. The
502 * resulting {@code long} value is returned.
503 *
504 * <p>Note that neither the character {@code L}
505 * ({@code '\u005Cu004C'}) nor {@code l}
506 * ({@code '\u005Cu006C'}) is permitted to appear at the end
507 * of the string as a type indicator, as would be permitted in
508 * Java programming language source code - except that either
509 * {@code L} or {@code l} may appear as a digit for a
510 * radix greater than or equal to 22.
511 *
512 * <p>An exception of type {@code NumberFormatException} is
513 * thrown if any of the following situations occurs:
514 * <ul>
515 *
516 * <li>The first argument is {@code null} or is a string of
517 * length zero.
518 *
519 * <li>The {@code radix} is either smaller than {@link
520 * java.lang.Character#MIN_RADIX} or larger than {@link
521 * java.lang.Character#MAX_RADIX}.
522 *
523 * <li>Any character of the string is not a digit of the specified
524 * radix, except that the first character may be a minus sign
525 * {@code '-'} ({@code '\u005Cu002d'}) or plus sign {@code
526 * '+'} ({@code '\u005Cu002B'}) provided that the string is
527 * longer than length 1.
528 *
529 * <li>The value represented by the string is not a value of type
530 * {@code long}.
531 * </ul>
532 *
533 * <p>Examples:
534 * <blockquote><pre>
535 * parseLong("0", 10) returns 0L
536 * parseLong("473", 10) returns 473L
537 * parseLong("+42", 10) returns 42L
538 * parseLong("-0", 10) returns 0L
539 * parseLong("-FF", 16) returns -255L
540 * parseLong("1100110", 2) returns 102L
541 * parseLong("99", 8) throws a NumberFormatException
542 * parseLong("Hazelnut", 10) throws a NumberFormatException
543 * parseLong("Hazelnut", 36) returns 1356099454469L
544 * </pre></blockquote>
545 *
546 * @param s the {@code String} containing the
547 * {@code long} representation to be parsed.
548 * @param radix the radix to be used while parsing {@code s}.
549 * @return the {@code long} represented by the string argument in
550 * the specified radix.
551 * @throws NumberFormatException if the string does not contain a
552 * parsable {@code long}.
553 */
554 public static long parseLong(String s, int radix)
555 throws NumberFormatException {
556 if (s == null) {
557 throw new NumberFormatException("Cannot parse null string");
558 }
559
560 if (radix < Character.MIN_RADIX) {
561 throw new NumberFormatException(String.format(
562 "radix %s less than Character.MIN_RADIX", radix));
563 }
564
565 if (radix > Character.MAX_RADIX) {
566 throw new NumberFormatException(String.format(
567 "radix %s greater than Character.MAX_RADIX", radix));
568 }
569
570 int len = s.length();
571 if (len == 0) {
572 throw NumberFormatException.forInputString("", radix);
573 }
574 int digit = ~0xFF;
575 int i = 0;
576 char firstChar = s.charAt(i++);
577 if (firstChar != '-' && firstChar != '+') {
578 digit = digit(firstChar, radix);
579 }
580 if (digit >= 0 || digit == ~0xFF && len > 1) {
581 long limit = firstChar != '-' ? MIN_VALUE + 1 : MIN_VALUE;
582 long multmin = limit / radix;
583 long result = -(digit & 0xFF);
584 boolean inRange = true;
585 /* Accumulating negatively avoids surprises near MAX_VALUE */
586 while (i < len && (digit = digit(s.charAt(i++), radix)) >= 0
587 && (inRange = result > multmin
588 || result == multmin && digit <= (int) (radix * multmin - limit))) {
589 result = radix * result - digit;
590 }
591 if (inRange && i == len && digit >= 0) {
592 return firstChar != '-' ? -result : result;
593 }
594 }
595 throw NumberFormatException.forInputString(s, radix);
596 }
597
598 /**
599 * Parses the {@link CharSequence} argument as a signed {@code long} in
600 * the specified {@code radix}, beginning at the specified
601 * {@code beginIndex} and extending to {@code endIndex - 1}.
602 *
603 * <p>The method does not take steps to guard against the
604 * {@code CharSequence} being mutated while parsing.
605 *
606 * @param s the {@code CharSequence} containing the {@code long}
607 * representation to be parsed
608 * @param beginIndex the beginning index, inclusive.
609 * @param endIndex the ending index, exclusive.
610 * @param radix the radix to be used while parsing {@code s}.
611 * @return the signed {@code long} represented by the subsequence in
612 * the specified radix.
613 * @throws NullPointerException if {@code s} is null.
614 * @throws IndexOutOfBoundsException if {@code beginIndex} is
615 * negative, or if {@code beginIndex} is greater than
616 * {@code endIndex} or if {@code endIndex} is greater than
617 * {@code s.length()}.
618 * @throws NumberFormatException if the {@code CharSequence} does not
619 * contain a parsable {@code long} in the specified
620 * {@code radix}, or if {@code radix} is either smaller than
621 * {@link java.lang.Character#MIN_RADIX} or larger than
622 * {@link java.lang.Character#MAX_RADIX}.
623 * @since 9
624 */
625 public static long parseLong(CharSequence s, int beginIndex, int endIndex, int radix)
626 throws NumberFormatException {
627 Objects.requireNonNull(s);
628 Objects.checkFromToIndex(beginIndex, endIndex, s.length());
629
630 if (radix < Character.MIN_RADIX) {
631 throw new NumberFormatException(String.format(
632 "radix %s less than Character.MIN_RADIX", radix));
633 }
634
635 if (radix > Character.MAX_RADIX) {
636 throw new NumberFormatException(String.format(
637 "radix %s greater than Character.MAX_RADIX", radix));
638 }
639
640 /*
641 * While s can be concurrently modified, it is ensured that each
642 * of its characters is read at most once, from lower to higher indices.
643 * This is obtained by reading them using the pattern s.charAt(i++),
644 * and by not updating i anywhere else.
645 */
646 if (beginIndex == endIndex) {
647 throw NumberFormatException.forInputString("", radix);
648 }
649 int digit = ~0xFF; // ~0xFF means firstChar char is sign
650 int i = beginIndex;
651 char firstChar = s.charAt(i++);
652 if (firstChar != '-' && firstChar != '+') {
653 digit = digit(firstChar, radix);
654 }
655 if (digit >= 0 || digit == ~0xFF && endIndex - beginIndex > 1) {
656 long limit = firstChar != '-' ? MIN_VALUE + 1 : MIN_VALUE;
657 long multmin = limit / radix;
658 long result = -(digit & 0xFF);
659 boolean inRange = true;
660 /* Accumulating negatively avoids surprises near MAX_VALUE */
661 while (i < endIndex && (digit = digit(s.charAt(i++), radix)) >= 0
662 && (inRange = result > multmin
663 || result == multmin && digit <= (int) (radix * multmin - limit))) {
664 result = radix * result - digit;
665 }
666 if (inRange && i == endIndex && digit >= 0) {
667 return firstChar != '-' ? -result : result;
668 }
669 }
670 throw NumberFormatException.forCharSequence(s, beginIndex,
671 endIndex, i - (digit < -1 ? 0 : 1));
672 }
673
674 /**
675 * Parses the string argument as a signed decimal {@code long}.
676 * The characters in the string must all be decimal digits, except
677 * that the first character may be an ASCII minus sign {@code '-'}
678 * ({@code \u005Cu002D'}) to indicate a negative value or an
679 * ASCII plus sign {@code '+'} ({@code '\u005Cu002B'}) to
680 * indicate a positive value. The resulting {@code long} value is
681 * returned, exactly as if the argument and the radix {@code 10}
682 * were given as arguments to the {@link
683 * #parseLong(java.lang.String, int)} method.
684 *
685 * <p>Note that neither the character {@code L}
686 * ({@code '\u005Cu004C'}) nor {@code l}
687 * ({@code '\u005Cu006C'}) is permitted to appear at the end
688 * of the string as a type indicator, as would be permitted in
689 * Java programming language source code.
690 *
691 * @param s a {@code String} containing the {@code long}
692 * representation to be parsed
693 * @return the {@code long} represented by the argument in
694 * decimal.
695 * @throws NumberFormatException if the string does not contain a
696 * parsable {@code long}.
697 */
698 public static long parseLong(String s) throws NumberFormatException {
699 return parseLong(s, 10);
700 }
701
702 /**
703 * Parses the string argument as an unsigned {@code long} in the
704 * radix specified by the second argument. An unsigned integer
705 * maps the values usually associated with negative numbers to
706 * positive numbers larger than {@code MAX_VALUE}.
707 *
708 * The characters in the string must all be digits of the
709 * specified radix (as determined by whether {@link
710 * java.lang.Character#digit(char, int)} returns a nonnegative
711 * value), except that the first character may be an ASCII plus
712 * sign {@code '+'} ({@code '\u005Cu002B'}). The resulting
713 * integer value is returned.
714 *
715 * <p>An exception of type {@code NumberFormatException} is
716 * thrown if any of the following situations occurs:
717 * <ul>
718 * <li>The first argument is {@code null} or is a string of
719 * length zero.
720 *
721 * <li>The radix is either smaller than
722 * {@link java.lang.Character#MIN_RADIX} or
723 * larger than {@link java.lang.Character#MAX_RADIX}.
724 *
725 * <li>Any character of the string is not a digit of the specified
726 * radix, except that the first character may be a plus sign
727 * {@code '+'} ({@code '\u005Cu002B'}) provided that the
728 * string is longer than length 1.
729 *
730 * <li>The value represented by the string is larger than the
731 * largest unsigned {@code long}, 2<sup>64</sup>-1.
732 *
733 * </ul>
734 *
735 *
736 * @param s the {@code String} containing the unsigned integer
737 * representation to be parsed
738 * @param radix the radix to be used while parsing {@code s}.
739 * @return the unsigned {@code long} represented by the string
740 * argument in the specified radix.
741 * @throws NumberFormatException if the {@code String}
742 * does not contain a parsable {@code long}.
743 * @since 1.8
744 */
745 public static long parseUnsignedLong(String s, int radix)
746 throws NumberFormatException {
747 if (s == null) {
748 throw new NumberFormatException("Cannot parse null string");
749 }
750
751 if (radix < Character.MIN_RADIX) {
752 throw new NumberFormatException(String.format(
753 "radix %s less than Character.MIN_RADIX", radix));
754 }
755
756 if (radix > Character.MAX_RADIX) {
757 throw new NumberFormatException(String.format(
758 "radix %s greater than Character.MAX_RADIX", radix));
759 }
760
761 int len = s.length();
762 if (len == 0) {
763 throw NumberFormatException.forInputString(s, radix);
764 }
765 int i = 0;
766 char firstChar = s.charAt(i++);
767 if (firstChar == '-') {
768 throw new NumberFormatException(String.format(
769 "Illegal leading minus sign on unsigned string %s.", s));
770 }
771 int digit = ~0xFF;
772 if (firstChar != '+') {
773 digit = digit(firstChar, radix);
774 }
775 if (digit >= 0 || digit == ~0xFF && len > 1) {
776 long multmax = divideUnsigned(-1L, radix); // -1L is max unsigned long
777 long result = digit & 0xFF;
778 boolean inRange = true;
779 while (i < len && (digit = digit(s.charAt(i++), radix)) >= 0
780 && (inRange = compareUnsigned(result, multmax) < 0
781 || result == multmax && digit < (int) (-radix * multmax))) {
782 result = radix * result + digit;
783 }
784 if (inRange && i == len && digit >= 0) {
785 return result;
786 }
787 }
788 if (digit < 0) {
789 throw NumberFormatException.forInputString(s, radix);
790 }
791 throw new NumberFormatException(String.format(
792 "String value %s exceeds range of unsigned long.", s));
793 }
794
795 /**
796 * Parses the {@link CharSequence} argument as an unsigned {@code long} in
797 * the specified {@code radix}, beginning at the specified
798 * {@code beginIndex} and extending to {@code endIndex - 1}.
799 *
800 * <p>The method does not take steps to guard against the
801 * {@code CharSequence} being mutated while parsing.
802 *
803 * @param s the {@code CharSequence} containing the unsigned
804 * {@code long} representation to be parsed
805 * @param beginIndex the beginning index, inclusive.
806 * @param endIndex the ending index, exclusive.
807 * @param radix the radix to be used while parsing {@code s}.
808 * @return the unsigned {@code long} represented by the subsequence in
809 * the specified radix.
810 * @throws NullPointerException if {@code s} is null.
811 * @throws IndexOutOfBoundsException if {@code beginIndex} is
812 * negative, or if {@code beginIndex} is greater than
813 * {@code endIndex} or if {@code endIndex} is greater than
814 * {@code s.length()}.
815 * @throws NumberFormatException if the {@code CharSequence} does not
816 * contain a parsable unsigned {@code long} in the specified
817 * {@code radix}, or if {@code radix} is either smaller than
818 * {@link java.lang.Character#MIN_RADIX} or larger than
819 * {@link java.lang.Character#MAX_RADIX}.
820 * @since 9
821 */
822 public static long parseUnsignedLong(CharSequence s, int beginIndex, int endIndex, int radix)
823 throws NumberFormatException {
824 Objects.requireNonNull(s);
825 Objects.checkFromToIndex(beginIndex, endIndex, s.length());
826
827 if (radix < Character.MIN_RADIX) {
828 throw new NumberFormatException(String.format(
829 "radix %s less than Character.MIN_RADIX", radix));
830 }
831
832 if (radix > Character.MAX_RADIX) {
833 throw new NumberFormatException(String.format(
834 "radix %s greater than Character.MAX_RADIX", radix));
835 }
836
837 /*
838 * While s can be concurrently modified, it is ensured that each
839 * of its characters is read at most once, from lower to higher indices.
840 * This is obtained by reading them using the pattern s.charAt(i++),
841 * and by not updating i anywhere else.
842 */
843 if (beginIndex == endIndex) {
844 throw NumberFormatException.forInputString("", radix);
845 }
846 int i = beginIndex;
847 char firstChar = s.charAt(i++);
848 if (firstChar == '-') {
849 throw new NumberFormatException(
850 "Illegal leading minus sign on unsigned string " + s + ".");
851 }
852 int digit = ~0xFF;
853 if (firstChar != '+') {
854 digit = digit(firstChar, radix);
855 }
856 if (digit >= 0 || digit == ~0xFF && endIndex - beginIndex > 1) {
857 long multmax = divideUnsigned(-1L, radix); // -1L is max unsigned long
858 long result = digit & 0xFF;
859 boolean inRange = true;
860 while (i < endIndex && (digit = digit(s.charAt(i++), radix)) >= 0
861 && (inRange = compareUnsigned(result, multmax) < 0
862 || result == multmax && digit < (int) (-radix * multmax))) {
863 result = radix * result + digit;
864 }
865 if (inRange && i == endIndex && digit >= 0) {
866 return result;
867 }
868 }
869 if (digit < 0) {
870 throw NumberFormatException.forCharSequence(s, beginIndex,
871 endIndex, i - (digit < -1 ? 0 : 1));
872 }
873 throw new NumberFormatException(String.format(
874 "String value %s exceeds range of unsigned long.", s));
875 }
876
877 /**
878 * Parses the string argument as an unsigned decimal {@code long}. The
879 * characters in the string must all be decimal digits, except
880 * that the first character may be an ASCII plus sign {@code
881 * '+'} ({@code '\u005Cu002B'}). The resulting integer value
882 * is returned, exactly as if the argument and the radix 10 were
883 * given as arguments to the {@link
884 * #parseUnsignedLong(java.lang.String, int)} method.
885 *
886 * @param s a {@code String} containing the unsigned {@code long}
887 * representation to be parsed
888 * @return the unsigned {@code long} value represented by the decimal string argument
889 * @throws NumberFormatException if the string does not contain a
890 * parsable unsigned integer.
891 * @since 1.8
892 */
893 public static long parseUnsignedLong(String s) throws NumberFormatException {
894 return parseUnsignedLong(s, 10);
895 }
896
897 /**
898 * Returns a {@code Long} object holding the value
899 * extracted from the specified {@code String} when parsed
900 * with the radix given by the second argument. The first
901 * argument is interpreted as representing a signed
902 * {@code long} in the radix specified by the second
903 * argument, exactly as if the arguments were given to the {@link
904 * #parseLong(java.lang.String, int)} method. The result is a
905 * {@code Long} object that represents the {@code long}
906 * value specified by the string.
907 *
908 * <p>In other words, this method returns a {@code Long} object equal
909 * to the value of:
910 *
911 * <blockquote>
912 * {@code Long.valueOf(Long.parseLong(s, radix))}
913 * </blockquote>
914 *
915 * @param s the string to be parsed
916 * @param radix the radix to be used in interpreting {@code s}
917 * @return a {@code Long} object holding the value
918 * represented by the string argument in the specified
919 * radix.
920 * @throws NumberFormatException If the {@code String} does not
921 * contain a parsable {@code long}.
922 */
923 public static Long valueOf(String s, int radix) throws NumberFormatException {
924 return Long.valueOf(parseLong(s, radix));
925 }
926
927 /**
928 * Returns a {@code Long} object holding the value
929 * of the specified {@code String}. The argument is
930 * interpreted as representing a signed decimal {@code long},
931 * exactly as if the argument were given to the {@link
932 * #parseLong(java.lang.String)} method. The result is a
933 * {@code Long} object that represents the integer value
934 * specified by the string.
935 *
936 * <p>In other words, this method returns a {@code Long} object
937 * equal to the value of:
938 *
939 * <blockquote>
940 * {@code Long.valueOf(Long.parseLong(s))}
941 * </blockquote>
942 *
943 * @param s the string to be parsed.
944 * @return a {@code Long} object holding the value
945 * represented by the string argument.
946 * @throws NumberFormatException If the string cannot be parsed
947 * as a {@code long}.
948 */
949 public static Long valueOf(String s) throws NumberFormatException
950 {
951 return Long.valueOf(parseLong(s, 10));
952 }
953
954 private static final class LongCache {
955 private LongCache() {}
956
957 @Stable
958 static final Long[] cache;
959 static Long[] archivedCache;
960
961 static {
962 int size = -(-128) + 127 + 1;
963
964 // Load and use the archived cache if it exists
965 CDS.initializeFromArchive(LongCache.class);
966 if (archivedCache == null || archivedCache.length != size) {
967 Long[] c = new Long[size];
968 long value = -128;
969 for(int i = 0; i < size; i++) {
970 c[i] = new Long(value++);
971 }
972 archivedCache = c;
973 }
974 cache = archivedCache;
975 }
976 }
977
978 /**
979 * Returns a {@code Long} instance representing the specified
980 * {@code long} value.
981 * If a new {@code Long} instance is not required, this method
982 * should generally be used in preference to the constructor
983 * {@link #Long(long)}, as this method is likely to yield
984 * significantly better space and time performance by caching
985 * frequently requested values.
986 *
987 * This method will always cache values in the range -128 to 127,
988 * inclusive, and may cache other values outside of this range.
989 *
990 * @param l a long value.
991 * @return a {@code Long} instance representing {@code l}.
992 * @since 1.5
993 */
994 @IntrinsicCandidate
995 @DeserializeConstructor
996 public static Long valueOf(long l) {
997 final int offset = 128;
998 if (l >= -128 && l <= 127) { // will cache
999 return LongCache.cache[(int)l + offset];
1000 }
1001 return new Long(l);
1002 }
1003
1004 /**
1005 * Decodes a {@code String} into a {@code Long}.
1006 * Accepts decimal, hexadecimal, and octal numbers given by the
1007 * following grammar:
1008 *
1009 * <blockquote>
1010 * <dl>
1011 * <dt><i>DecodableString:</i>
1012 * <dd><i>Sign<sub>opt</sub> DecimalNumeral</i>
1013 * <dd><i>Sign<sub>opt</sub></i> {@code 0x} <i>HexDigits</i>
1014 * <dd><i>Sign<sub>opt</sub></i> {@code 0X} <i>HexDigits</i>
1015 * <dd><i>Sign<sub>opt</sub></i> {@code #} <i>HexDigits</i>
1016 * <dd><i>Sign<sub>opt</sub></i> {@code 0} <i>OctalDigits</i>
1017 *
1018 * <dt><i>Sign:</i>
1019 * <dd>{@code -}
1020 * <dd>{@code +}
1021 * </dl>
1022 * </blockquote>
1023 *
1024 * <i>DecimalNumeral</i>, <i>HexDigits</i>, and <i>OctalDigits</i>
1025 * are as defined in section {@jls 3.10.1} of
1026 * <cite>The Java Language Specification</cite>,
1027 * except that underscores are not accepted between digits.
1028 *
1029 * <p>The sequence of characters following an optional
1030 * sign and/or radix specifier ("{@code 0x}", "{@code 0X}",
1031 * "{@code #}", or leading zero) is parsed as by the {@code
1032 * Long.parseLong} method with the indicated radix (10, 16, or 8).
1033 * This sequence of characters must represent a positive value or
1034 * a {@link NumberFormatException} will be thrown. The result is
1035 * negated if first character of the specified {@code String} is
1036 * the minus sign. No whitespace characters are permitted in the
1037 * {@code String}.
1038 *
1039 * @param nm the {@code String} to decode.
1040 * @return a {@code Long} object holding the {@code long}
1041 * value represented by {@code nm}
1042 * @throws NumberFormatException if the {@code String} does not
1043 * contain a parsable {@code long}.
1044 * @see java.lang.Long#parseLong(String, int)
1045 * @since 1.2
1046 */
1047 public static Long decode(String nm) throws NumberFormatException {
1048 int radix = 10;
1049 int index = 0;
1050 boolean negative = false;
1051 long result;
1052
1053 if (nm.isEmpty())
1054 throw new NumberFormatException("Zero length string");
1055 char firstChar = nm.charAt(0);
1056 // Handle sign, if present
1057 if (firstChar == '-') {
1058 negative = true;
1059 index++;
1060 } else if (firstChar == '+')
1061 index++;
1062
1063 // Handle radix specifier, if present
1064 if (nm.startsWith("0x", index) || nm.startsWith("0X", index)) {
1065 index += 2;
1066 radix = 16;
1067 }
1068 else if (nm.startsWith("#", index)) {
1069 index ++;
1070 radix = 16;
1071 }
1072 else if (nm.startsWith("0", index) && nm.length() > 1 + index) {
1073 index ++;
1074 radix = 8;
1075 }
1076
1077 if (nm.startsWith("-", index) || nm.startsWith("+", index))
1078 throw new NumberFormatException("Sign character in wrong position");
1079
1080 try {
1081 result = parseLong(nm, index, nm.length(), radix);
1082 result = negative ? -result : result;
1083 } catch (NumberFormatException e) {
1084 // If number is Long.MIN_VALUE, we'll end up here. The next line
1085 // handles this case, and causes any genuine format error to be
1086 // rethrown.
1087 String constant = negative ? ("-" + nm.substring(index))
1088 : nm.substring(index);
1089 result = parseLong(constant, radix);
1090 }
1091 return result;
1092 }
1093
1094 /**
1095 * The value of the {@code Long}.
1096 *
1097 * @serial
1098 */
1099 private final long value;
1100
1101 /**
1102 * Constructs a newly allocated {@code Long} object that
1103 * represents the specified {@code long} argument.
1104 *
1105 * @param value the value to be represented by the
1106 * {@code Long} object.
1107 *
1108 * @deprecated
1109 * It is rarely appropriate to use this constructor. The static factory
1110 * {@link #valueOf(long)} is generally a better choice, as it is
1111 * likely to yield significantly better space and time performance.
1112 */
1113 @Deprecated(since="9", forRemoval = true)
1114 public Long(long value) {
1115 this.value = value;
1116 }
1117
1118 /**
1119 * Constructs a newly allocated {@code Long} object that
1120 * represents the {@code long} value indicated by the
1121 * {@code String} parameter. The string is converted to a
1122 * {@code long} value in exactly the manner used by the
1123 * {@code parseLong} method for radix 10.
1124 *
1125 * @param s the {@code String} to be converted to a
1126 * {@code Long}.
1127 * @throws NumberFormatException if the {@code String} does not
1128 * contain a parsable {@code long}.
1129 *
1130 * @deprecated
1131 * It is rarely appropriate to use this constructor.
1132 * Use {@link #parseLong(String)} to convert a string to a
1133 * {@code long} primitive, or use {@link #valueOf(String)}
1134 * to convert a string to a {@code Long} object.
1135 */
1136 @Deprecated(since="9", forRemoval = true)
1137 public Long(String s) throws NumberFormatException {
1138 this.value = parseLong(s, 10);
1139 }
1140
1141 /**
1142 * Returns the value of this {@code Long} as a {@code byte} after
1143 * a narrowing primitive conversion.
1144 * @jls 5.1.3 Narrowing Primitive Conversion
1145 */
1146 public byte byteValue() {
1147 return (byte)value;
1148 }
1149
1150 /**
1151 * Returns the value of this {@code Long} as a {@code short} after
1152 * a narrowing primitive conversion.
1153 * @jls 5.1.3 Narrowing Primitive Conversion
1154 */
1155 public short shortValue() {
1156 return (short)value;
1157 }
1158
1159 /**
1160 * Returns the value of this {@code Long} as an {@code int} after
1161 * a narrowing primitive conversion.
1162 * @jls 5.1.3 Narrowing Primitive Conversion
1163 */
1164 public int intValue() {
1165 return (int)value;
1166 }
1167
1168 /**
1169 * Returns the value of this {@code Long} as a
1170 * {@code long} value.
1171 */
1172 @IntrinsicCandidate
1173 public long longValue() {
1174 return value;
1175 }
1176
1177 /**
1178 * Returns the value of this {@code Long} as a {@code float} after
1179 * a widening primitive conversion.
1180 * @jls 5.1.2 Widening Primitive Conversion
1181 */
1182 public float floatValue() {
1183 return (float)value;
1184 }
1185
1186 /**
1187 * Returns the value of this {@code Long} as a {@code double}
1188 * after a widening primitive conversion.
1189 * @jls 5.1.2 Widening Primitive Conversion
1190 */
1191 public double doubleValue() {
1192 return (double)value;
1193 }
1194
1195 /**
1196 * Returns a {@code String} object representing this
1197 * {@code Long}'s value. The value is converted to signed
1198 * decimal representation and returned as a string, exactly as if
1199 * the {@code long} value were given as an argument to the
1200 * {@link java.lang.Long#toString(long)} method.
1201 *
1202 * @return a string representation of the value of this object in
1203 * base 10.
1204 */
1205 public String toString() {
1206 return toString(value);
1207 }
1208
1209 /**
1210 * Returns a hash code for this {@code Long}. The result is
1211 * the exclusive OR of the two halves of the primitive
1212 * {@code long} value held by this {@code Long}
1213 * object. That is, the hashcode is the value of the expression:
1214 *
1215 * <blockquote>
1216 * {@code (int)(this.longValue()^(this.longValue()>>>32))}
1217 * </blockquote>
1218 *
1219 * @return a hash code value for this object.
1220 */
1221 @Override
1222 public int hashCode() {
1223 return Long.hashCode(value);
1224 }
1225
1226 /**
1227 * Returns a hash code for a {@code long} value; compatible with
1228 * {@code Long.hashCode()}.
1229 *
1230 * @param value the value to hash
1231 * @return a hash code value for a {@code long} value.
1232 * @since 1.8
1233 */
1234 public static int hashCode(long value) {
1235 return (int)(value ^ (value >>> 32));
1236 }
1237
1238 /**
1239 * Compares this object to the specified object. The result is
1240 * {@code true} if and only if the argument is not
1241 * {@code null} and is a {@code Long} object that
1242 * contains the same {@code long} value as this object.
1243 *
1244 * @param obj the object to compare with.
1245 * @return {@code true} if the objects are the same;
1246 * {@code false} otherwise.
1247 */
1248 public boolean equals(Object obj) {
1249 if (obj instanceof Long) {
1250 return value == ((Long)obj).longValue();
1251 }
1252 return false;
1253 }
1254
1255 /**
1256 * Determines the {@code long} value of the system property
1257 * with the specified name.
1258 *
1259 * <p>The first argument is treated as the name of a system
1260 * property. System properties are accessible through the {@link
1261 * java.lang.System#getProperty(java.lang.String)} method. The
1262 * string value of this property is then interpreted as a {@code
1263 * long} value using the grammar supported by {@link Long#decode decode}
1264 * and a {@code Long} object representing this value is returned.
1265 *
1266 * <p>If there is no property with the specified name, if the
1267 * specified name is empty or {@code null}, or if the property
1268 * does not have the correct numeric format, then {@code null} is
1269 * returned.
1270 *
1271 * <p>In other words, this method returns a {@code Long} object
1272 * equal to the value of:
1273 *
1274 * <blockquote>
1275 * {@code getLong(nm, null)}
1276 * </blockquote>
1277 *
1278 * @param nm property name.
1279 * @return the {@code Long} value of the property.
1280 * @throws SecurityException for the same reasons as
1281 * {@link System#getProperty(String) System.getProperty}
1282 * @see java.lang.System#getProperty(java.lang.String)
1283 * @see java.lang.System#getProperty(java.lang.String, java.lang.String)
1284 */
1285 public static Long getLong(String nm) {
1286 return getLong(nm, null);
1287 }
1288
1289 /**
1290 * Determines the {@code long} value of the system property
1291 * with the specified name.
1292 *
1293 * <p>The first argument is treated as the name of a system
1294 * property. System properties are accessible through the {@link
1295 * java.lang.System#getProperty(java.lang.String)} method. The
1296 * string value of this property is then interpreted as a {@code
1297 * long} value using the grammar supported by {@link Long#decode decode}
1298 * and a {@code Long} object representing this value is returned.
1299 *
1300 * <p>The second argument is the default value. A {@code Long} object
1301 * that represents the value of the second argument is returned if there
1302 * is no property of the specified name, if the property does not have
1303 * the correct numeric format, or if the specified name is empty or null.
1304 *
1305 * <p>In other words, this method returns a {@code Long} object equal
1306 * to the value of:
1307 *
1308 * <blockquote>
1309 * {@code getLong(nm, Long.valueOf(val))}
1310 * </blockquote>
1311 *
1312 * but in practice it may be implemented in a manner such as:
1313 *
1314 * <blockquote><pre>
1315 * Long result = getLong(nm, null);
1316 * return (result == null) ? Long.valueOf(val) : result;
1317 * </pre></blockquote>
1318 *
1319 * to avoid the unnecessary allocation of a {@code Long} object when
1320 * the default value is not needed.
1321 *
1322 * @param nm property name.
1323 * @param val default value.
1324 * @return the {@code Long} value of the property.
1325 * @throws SecurityException for the same reasons as
1326 * {@link System#getProperty(String) System.getProperty}
1327 * @see java.lang.System#getProperty(java.lang.String)
1328 * @see java.lang.System#getProperty(java.lang.String, java.lang.String)
1329 */
1330 public static Long getLong(String nm, long val) {
1331 Long result = Long.getLong(nm, null);
1332 return (result == null) ? Long.valueOf(val) : result;
1333 }
1334
1335 /**
1336 * Returns the {@code long} value of the system property with
1337 * the specified name. The first argument is treated as the name
1338 * of a system property. System properties are accessible through
1339 * the {@link java.lang.System#getProperty(java.lang.String)}
1340 * method. The string value of this property is then interpreted
1341 * as a {@code long} value, as per the
1342 * {@link Long#decode decode} method, and a {@code Long} object
1343 * representing this value is returned; in summary:
1344 *
1345 * <ul>
1346 * <li>If the property value begins with the two ASCII characters
1347 * {@code 0x} or the ASCII character {@code #}, not followed by
1348 * a minus sign, then the rest of it is parsed as a hexadecimal integer
1349 * exactly as for the method {@link #valueOf(java.lang.String, int)}
1350 * with radix 16.
1351 * <li>If the property value begins with the ASCII character
1352 * {@code 0} followed by another character, it is parsed as
1353 * an octal integer exactly as by the method {@link
1354 * #valueOf(java.lang.String, int)} with radix 8.
1355 * <li>Otherwise the property value is parsed as a decimal
1356 * integer exactly as by the method
1357 * {@link #valueOf(java.lang.String, int)} with radix 10.
1358 * </ul>
1359 *
1360 * <p>Note that, in every case, neither {@code L}
1361 * ({@code '\u005Cu004C'}) nor {@code l}
1362 * ({@code '\u005Cu006C'}) is permitted to appear at the end
1363 * of the property value as a type indicator, as would be
1364 * permitted in Java programming language source code.
1365 *
1366 * <p>The second argument is the default value. The default value is
1367 * returned if there is no property of the specified name, if the
1368 * property does not have the correct numeric format, or if the
1369 * specified name is empty or {@code null}.
1370 *
1371 * @param nm property name.
1372 * @param val default value.
1373 * @return the {@code Long} value of the property.
1374 * @throws SecurityException for the same reasons as
1375 * {@link System#getProperty(String) System.getProperty}
1376 * @see System#getProperty(java.lang.String)
1377 * @see System#getProperty(java.lang.String, java.lang.String)
1378 */
1379 public static Long getLong(String nm, Long val) {
1380 String v = null;
1381 try {
1382 v = System.getProperty(nm);
1383 } catch (IllegalArgumentException | NullPointerException e) {
1384 }
1385 if (v != null) {
1386 try {
1387 return Long.decode(v);
1388 } catch (NumberFormatException e) {
1389 }
1390 }
1391 return val;
1392 }
1393
1394 /**
1395 * Compares two {@code Long} objects numerically.
1396 *
1397 * @param anotherLong the {@code Long} to be compared.
1398 * @return the value {@code 0} if this {@code Long} is
1399 * equal to the argument {@code Long}; a value less than
1400 * {@code 0} if this {@code Long} is numerically less
1401 * than the argument {@code Long}; and a value greater
1402 * than {@code 0} if this {@code Long} is numerically
1403 * greater than the argument {@code Long} (signed
1404 * comparison).
1405 * @since 1.2
1406 */
1407 public int compareTo(Long anotherLong) {
1408 return compare(this.value, anotherLong.value);
1409 }
1410
1411 /**
1412 * Compares two {@code long} values numerically.
1413 * The value returned is identical to what would be returned by:
1414 * <pre>
1415 * Long.valueOf(x).compareTo(Long.valueOf(y))
1416 * </pre>
1417 *
1418 * @param x the first {@code long} to compare
1419 * @param y the second {@code long} to compare
1420 * @return the value {@code 0} if {@code x == y};
1421 * a value less than {@code 0} if {@code x < y}; and
1422 * a value greater than {@code 0} if {@code x > y}
1423 * @since 1.7
1424 */
1425 public static int compare(long x, long y) {
1426 return (x < y) ? -1 : ((x == y) ? 0 : 1);
1427 }
1428
1429 /**
1430 * Compares two {@code long} values numerically treating the values
1431 * as unsigned.
1432 *
1433 * @param x the first {@code long} to compare
1434 * @param y the second {@code long} to compare
1435 * @return the value {@code 0} if {@code x == y}; a value less
1436 * than {@code 0} if {@code x < y} as unsigned values; and
1437 * a value greater than {@code 0} if {@code x > y} as
1438 * unsigned values
1439 * @since 1.8
1440 */
1441 @IntrinsicCandidate
1442 public static int compareUnsigned(long x, long y) {
1443 return compare(x + MIN_VALUE, y + MIN_VALUE);
1444 }
1445
1446
1447 /**
1448 * Returns the unsigned quotient of dividing the first argument by
1449 * the second where each argument and the result is interpreted as
1450 * an unsigned value.
1451 *
1452 * <p>Note that in two's complement arithmetic, the three other
1453 * basic arithmetic operations of add, subtract, and multiply are
1454 * bit-wise identical if the two operands are regarded as both
1455 * being signed or both being unsigned. Therefore separate {@code
1456 * addUnsigned}, etc. methods are not provided.
1457 *
1458 * @param dividend the value to be divided
1459 * @param divisor the value doing the dividing
1460 * @return the unsigned quotient of the first argument divided by
1461 * the second argument
1462 * @see #remainderUnsigned
1463 * @since 1.8
1464 */
1465 @IntrinsicCandidate
1466 public static long divideUnsigned(long dividend, long divisor) {
1467 /* See Hacker's Delight (2nd ed), section 9.3 */
1468 if (divisor >= 0) {
1469 final long q = (dividend >>> 1) / divisor << 1;
1470 final long r = dividend - q * divisor;
1471 return q + ((r | ~(r - divisor)) >>> (Long.SIZE - 1));
1472 }
1473 return (dividend & ~(dividend - divisor)) >>> (Long.SIZE - 1);
1474 }
1475
1476 /**
1477 * Returns the unsigned remainder from dividing the first argument
1478 * by the second where each argument and the result is interpreted
1479 * as an unsigned value.
1480 *
1481 * @param dividend the value to be divided
1482 * @param divisor the value doing the dividing
1483 * @return the unsigned remainder of the first argument divided by
1484 * the second argument
1485 * @see #divideUnsigned
1486 * @since 1.8
1487 */
1488 @IntrinsicCandidate
1489 public static long remainderUnsigned(long dividend, long divisor) {
1490 /* See Hacker's Delight (2nd ed), section 9.3 */
1491 if (divisor >= 0) {
1492 final long q = (dividend >>> 1) / divisor << 1;
1493 final long r = dividend - q * divisor;
1494 /*
1495 * Here, 0 <= r < 2 * divisor
1496 * (1) When 0 <= r < divisor, the remainder is simply r.
1497 * (2) Otherwise the remainder is r - divisor.
1498 *
1499 * In case (1), r - divisor < 0. Applying ~ produces a long with
1500 * sign bit 0, so >> produces 0. The returned value is thus r.
1501 *
1502 * In case (2), a similar reasoning shows that >> produces -1,
1503 * so the returned value is r - divisor.
1504 */
1505 return r - ((~(r - divisor) >> (Long.SIZE - 1)) & divisor);
1506 }
1507 /*
1508 * (1) When dividend >= 0, the remainder is dividend.
1509 * (2) Otherwise
1510 * (2.1) When dividend < divisor, the remainder is dividend.
1511 * (2.2) Otherwise the remainder is dividend - divisor
1512 *
1513 * A reasoning similar to the above shows that the returned value
1514 * is as expected.
1515 */
1516 return dividend - (((dividend & ~(dividend - divisor)) >> (Long.SIZE - 1)) & divisor);
1517 }
1518
1519 // Bit Twiddling
1520
1521 /**
1522 * The number of bits used to represent a {@code long} value in two's
1523 * complement binary form.
1524 *
1525 * @since 1.5
1526 */
1527 @Native public static final int SIZE = 64;
1528
1529 /**
1530 * The number of bytes used to represent a {@code long} value in two's
1531 * complement binary form.
1532 *
1533 * @since 1.8
1534 */
1535 public static final int BYTES = SIZE / Byte.SIZE;
1536
1537 /**
1538 * Returns a {@code long} value with at most a single one-bit, in the
1539 * position of the highest-order ("leftmost") one-bit in the specified
1540 * {@code long} value. Returns zero if the specified value has no
1541 * one-bits in its two's complement binary representation, that is, if it
1542 * is equal to zero.
1543 *
1544 * @param i the value whose highest one bit is to be computed
1545 * @return a {@code long} value with a single one-bit, in the position
1546 * of the highest-order one-bit in the specified value, or zero if
1547 * the specified value is itself equal to zero.
1548 * @since 1.5
1549 */
1550 public static long highestOneBit(long i) {
1551 return i & (MIN_VALUE >>> numberOfLeadingZeros(i));
1552 }
1553
1554 /**
1555 * Returns a {@code long} value with at most a single one-bit, in the
1556 * position of the lowest-order ("rightmost") one-bit in the specified
1557 * {@code long} value. Returns zero if the specified value has no
1558 * one-bits in its two's complement binary representation, that is, if it
1559 * is equal to zero.
1560 *
1561 * @param i the value whose lowest one bit is to be computed
1562 * @return a {@code long} value with a single one-bit, in the position
1563 * of the lowest-order one-bit in the specified value, or zero if
1564 * the specified value is itself equal to zero.
1565 * @since 1.5
1566 */
1567 public static long lowestOneBit(long i) {
1568 // HD, Section 2-1
1569 return i & -i;
1570 }
1571
1572 /**
1573 * Returns the number of zero bits preceding the highest-order
1574 * ("leftmost") one-bit in the two's complement binary representation
1575 * of the specified {@code long} value. Returns 64 if the
1576 * specified value has no one-bits in its two's complement representation,
1577 * in other words if it is equal to zero.
1578 *
1579 * <p>Note that this method is closely related to the logarithm base 2.
1580 * For all positive {@code long} values x:
1581 * <ul>
1582 * <li>floor(log<sub>2</sub>(x)) = {@code 63 - numberOfLeadingZeros(x)}
1583 * <li>ceil(log<sub>2</sub>(x)) = {@code 64 - numberOfLeadingZeros(x - 1)}
1584 * </ul>
1585 *
1586 * @param i the value whose number of leading zeros is to be computed
1587 * @return the number of zero bits preceding the highest-order
1588 * ("leftmost") one-bit in the two's complement binary representation
1589 * of the specified {@code long} value, or 64 if the value
1590 * is equal to zero.
1591 * @since 1.5
1592 */
1593 @IntrinsicCandidate
1594 public static int numberOfLeadingZeros(long i) {
1595 int x = (int)(i >>> 32);
1596 return x == 0 ? 32 + Integer.numberOfLeadingZeros((int)i)
1597 : Integer.numberOfLeadingZeros(x);
1598 }
1599
1600 /**
1601 * Returns the number of zero bits following the lowest-order ("rightmost")
1602 * one-bit in the two's complement binary representation of the specified
1603 * {@code long} value. Returns 64 if the specified value has no
1604 * one-bits in its two's complement representation, in other words if it is
1605 * equal to zero.
1606 *
1607 * @param i the value whose number of trailing zeros is to be computed
1608 * @return the number of zero bits following the lowest-order ("rightmost")
1609 * one-bit in the two's complement binary representation of the
1610 * specified {@code long} value, or 64 if the value is equal
1611 * to zero.
1612 * @since 1.5
1613 */
1614 @IntrinsicCandidate
1615 public static int numberOfTrailingZeros(long i) {
1616 int x = (int)i;
1617 return x == 0 ? 32 + Integer.numberOfTrailingZeros((int)(i >>> 32))
1618 : Integer.numberOfTrailingZeros(x);
1619 }
1620
1621 /**
1622 * Returns the number of one-bits in the two's complement binary
1623 * representation of the specified {@code long} value. This function is
1624 * sometimes referred to as the <i>population count</i>.
1625 *
1626 * @param i the value whose bits are to be counted
1627 * @return the number of one-bits in the two's complement binary
1628 * representation of the specified {@code long} value.
1629 * @since 1.5
1630 */
1631 @IntrinsicCandidate
1632 public static int bitCount(long i) {
1633 // HD, Figure 5-2
1634 i = i - ((i >>> 1) & 0x5555555555555555L);
1635 i = (i & 0x3333333333333333L) + ((i >>> 2) & 0x3333333333333333L);
1636 i = (i + (i >>> 4)) & 0x0f0f0f0f0f0f0f0fL;
1637 i = i + (i >>> 8);
1638 i = i + (i >>> 16);
1639 i = i + (i >>> 32);
1640 return (int)i & 0x7f;
1641 }
1642
1643 /**
1644 * Returns the value obtained by rotating the two's complement binary
1645 * representation of the specified {@code long} value left by the
1646 * specified number of bits. (Bits shifted out of the left hand, or
1647 * high-order, side reenter on the right, or low-order.)
1648 *
1649 * <p>Note that left rotation with a negative distance is equivalent to
1650 * right rotation: {@code rotateLeft(val, -distance) == rotateRight(val,
1651 * distance)}. Note also that rotation by any multiple of 64 is a
1652 * no-op, so all but the last six bits of the rotation distance can be
1653 * ignored, even if the distance is negative: {@code rotateLeft(val,
1654 * distance) == rotateLeft(val, distance & 0x3F)}.
1655 *
1656 * @param i the value whose bits are to be rotated left
1657 * @param distance the number of bit positions to rotate left
1658 * @return the value obtained by rotating the two's complement binary
1659 * representation of the specified {@code long} value left by the
1660 * specified number of bits.
1661 * @since 1.5
1662 */
1663 public static long rotateLeft(long i, int distance) {
1664 return (i << distance) | (i >>> -distance);
1665 }
1666
1667 /**
1668 * Returns the value obtained by rotating the two's complement binary
1669 * representation of the specified {@code long} value right by the
1670 * specified number of bits. (Bits shifted out of the right hand, or
1671 * low-order, side reenter on the left, or high-order.)
1672 *
1673 * <p>Note that right rotation with a negative distance is equivalent to
1674 * left rotation: {@code rotateRight(val, -distance) == rotateLeft(val,
1675 * distance)}. Note also that rotation by any multiple of 64 is a
1676 * no-op, so all but the last six bits of the rotation distance can be
1677 * ignored, even if the distance is negative: {@code rotateRight(val,
1678 * distance) == rotateRight(val, distance & 0x3F)}.
1679 *
1680 * @param i the value whose bits are to be rotated right
1681 * @param distance the number of bit positions to rotate right
1682 * @return the value obtained by rotating the two's complement binary
1683 * representation of the specified {@code long} value right by the
1684 * specified number of bits.
1685 * @since 1.5
1686 */
1687 public static long rotateRight(long i, int distance) {
1688 return (i >>> distance) | (i << -distance);
1689 }
1690
1691 /**
1692 * Returns the value obtained by reversing the order of the bits in the
1693 * two's complement binary representation of the specified {@code long}
1694 * value.
1695 *
1696 * @param i the value to be reversed
1697 * @return the value obtained by reversing order of the bits in the
1698 * specified {@code long} value.
1699 * @since 1.5
1700 */
1701 @IntrinsicCandidate
1702 public static long reverse(long i) {
1703 // HD, Figure 7-1
1704 i = (i & 0x5555555555555555L) << 1 | (i >>> 1) & 0x5555555555555555L;
1705 i = (i & 0x3333333333333333L) << 2 | (i >>> 2) & 0x3333333333333333L;
1706 i = (i & 0x0f0f0f0f0f0f0f0fL) << 4 | (i >>> 4) & 0x0f0f0f0f0f0f0f0fL;
1707
1708 return reverseBytes(i);
1709 }
1710
1711 /**
1712 * Returns the value obtained by compressing the bits of the
1713 * specified {@code long} value, {@code i}, in accordance with
1714 * the specified bit mask.
1715 * <p>
1716 * For each one-bit value {@code mb} of the mask, from least
1717 * significant to most significant, the bit value of {@code i} at
1718 * the same bit location as {@code mb} is assigned to the compressed
1719 * value contiguously starting from the least significant bit location.
1720 * All the upper remaining bits of the compressed value are set
1721 * to zero.
1722 *
1723 * @apiNote
1724 * Consider the simple case of compressing the digits of a hexadecimal
1725 * value:
1726 * {@snippet lang="java" :
1727 * // Compressing drink to food
1728 * compress(0xCAFEBABEL, 0xFF00FFF0L) == 0xCABABL
1729 * }
1730 * Starting from the least significant hexadecimal digit at position 0
1731 * from the right, the mask {@code 0xFF00FFF0} selects hexadecimal digits
1732 * at positions 1, 2, 3, 6 and 7 of {@code 0xCAFEBABE}. The selected digits
1733 * occur in the resulting compressed value contiguously from digit position
1734 * 0 in the same order.
1735 * <p>
1736 * The following identities all return {@code true} and are helpful to
1737 * understand the behaviour of {@code compress}:
1738 * {@snippet lang="java" :
1739 * // Returns 1 if the bit at position n is one
1740 * compress(x, 1L << n) == (x >> n & 1)
1741 *
1742 * // Logical shift right
1743 * compress(x, -1L << n) == x >>> n
1744 *
1745 * // Any bits not covered by the mask are ignored
1746 * compress(x, m) == compress(x & m, m)
1747 *
1748 * // Compressing a value by itself
1749 * compress(m, m) == (m == -1 || m == 0) ? m : (1L << bitCount(m)) - 1
1750 *
1751 * // Expanding then compressing with the same mask
1752 * compress(expand(x, m), m) == x & compress(m, m)
1753 * }
1754 * <p>
1755 * The Sheep And Goats (SAG) operation (see Hacker's Delight, section 7.7)
1756 * can be implemented as follows:
1757 * {@snippet lang="java" :
1758 * long compressLeft(long i, long mask) {
1759 * // This implementation follows the description in Hacker's Delight which
1760 * // is informative. A more optimal implementation is:
1761 * // Long.compress(i, mask) << -Long.bitCount(mask)
1762 * return Long.reverse(
1763 * Long.compress(Long.reverse(i), Long.reverse(mask)));
1764 * }
1765 *
1766 * long sag(long i, long mask) {
1767 * return compressLeft(i, mask) | Long.compress(i, ~mask);
1768 * }
1769 *
1770 * // Separate the sheep from the goats
1771 * sag(0x00000000_CAFEBABEL, 0xFFFFFFFF_FF00FFF0L) == 0x00000000_CABABFEEL
1772 * }
1773 *
1774 * @param i the value whose bits are to be compressed
1775 * @param mask the bit mask
1776 * @return the compressed value
1777 * @see #expand
1778 * @since 19
1779 */
1780 @IntrinsicCandidate
1781 public static long compress(long i, long mask) {
1782 // See Hacker's Delight (2nd ed) section 7.4 Compress, or Generalized Extract
1783
1784 i = i & mask; // Clear irrelevant bits
1785 long maskCount = ~mask << 1; // Count 0's to right
1786
1787 for (int j = 0; j < 6; j++) {
1788 // Parallel prefix
1789 // Mask prefix identifies bits of the mask that have an odd number of 0's to the right
1790 long maskPrefix = parallelSuffix(maskCount);
1791 // Bits to move
1792 long maskMove = maskPrefix & mask;
1793 // Compress mask
1794 mask = (mask ^ maskMove) | (maskMove >>> (1 << j));
1795 // Bits of i to be moved
1796 long t = i & maskMove;
1797 // Compress i
1798 i = (i ^ t) | (t >>> (1 << j));
1799 // Adjust the mask count by identifying bits that have 0 to the right
1800 maskCount = maskCount & ~maskPrefix;
1801 }
1802 return i;
1803 }
1804
1805 /**
1806 * Returns the value obtained by expanding the bits of the
1807 * specified {@code long} value, {@code i}, in accordance with
1808 * the specified bit mask.
1809 * <p>
1810 * For each one-bit value {@code mb} of the mask, from least
1811 * significant to most significant, the next contiguous bit value
1812 * of {@code i} starting at the least significant bit is assigned
1813 * to the expanded value at the same bit location as {@code mb}.
1814 * All other remaining bits of the expanded value are set to zero.
1815 *
1816 * @apiNote
1817 * Consider the simple case of expanding the digits of a hexadecimal
1818 * value:
1819 * {@snippet lang="java" :
1820 * expand(0x0000CABABL, 0xFF00FFF0L) == 0xCA00BAB0L
1821 * }
1822 * Starting from the least significant hexadecimal digit at position 0
1823 * from the right, the mask {@code 0xFF00FFF0} selects the first five
1824 * hexadecimal digits of {@code 0x0000CABAB}. The selected digits occur
1825 * in the resulting expanded value in order at positions 1, 2, 3, 6, and 7.
1826 * <p>
1827 * The following identities all return {@code true} and are helpful to
1828 * understand the behaviour of {@code expand}:
1829 * {@snippet lang="java" :
1830 * // Logically shift right the bit at position 0
1831 * expand(x, 1L << n) == (x & 1) << n
1832 *
1833 * // Logically shift right
1834 * expand(x, -1L << n) == x << n
1835 *
1836 * // Expanding all bits returns the mask
1837 * expand(-1L, m) == m
1838 *
1839 * // Any bits not covered by the mask are ignored
1840 * expand(x, m) == expand(x, m) & m
1841 *
1842 * // Compressing then expanding with the same mask
1843 * expand(compress(x, m), m) == x & m
1844 * }
1845 * <p>
1846 * The select operation for determining the position of the one-bit with
1847 * index {@code n} in a {@code long} value can be implemented as follows:
1848 * {@snippet lang="java" :
1849 * long select(long i, long n) {
1850 * // the one-bit in i (the mask) with index n
1851 * long nthBit = Long.expand(1L << n, i);
1852 * // the bit position of the one-bit with index n
1853 * return Long.numberOfTrailingZeros(nthBit);
1854 * }
1855 *
1856 * // The one-bit with index 0 is at bit position 1
1857 * select(0b10101010_10101010, 0) == 1
1858 * // The one-bit with index 3 is at bit position 7
1859 * select(0b10101010_10101010, 3) == 7
1860 * }
1861 *
1862 * @param i the value whose bits are to be expanded
1863 * @param mask the bit mask
1864 * @return the expanded value
1865 * @see #compress
1866 * @since 19
1867 */
1868 @IntrinsicCandidate
1869 public static long expand(long i, long mask) {
1870 // Save original mask
1871 long originalMask = mask;
1872 // Count 0's to right
1873 long maskCount = ~mask << 1;
1874 long maskPrefix = parallelSuffix(maskCount);
1875 // Bits to move
1876 long maskMove1 = maskPrefix & mask;
1877 // Compress mask
1878 mask = (mask ^ maskMove1) | (maskMove1 >>> (1 << 0));
1879 maskCount = maskCount & ~maskPrefix;
1880
1881 maskPrefix = parallelSuffix(maskCount);
1882 // Bits to move
1883 long maskMove2 = maskPrefix & mask;
1884 // Compress mask
1885 mask = (mask ^ maskMove2) | (maskMove2 >>> (1 << 1));
1886 maskCount = maskCount & ~maskPrefix;
1887
1888 maskPrefix = parallelSuffix(maskCount);
1889 // Bits to move
1890 long maskMove3 = maskPrefix & mask;
1891 // Compress mask
1892 mask = (mask ^ maskMove3) | (maskMove3 >>> (1 << 2));
1893 maskCount = maskCount & ~maskPrefix;
1894
1895 maskPrefix = parallelSuffix(maskCount);
1896 // Bits to move
1897 long maskMove4 = maskPrefix & mask;
1898 // Compress mask
1899 mask = (mask ^ maskMove4) | (maskMove4 >>> (1 << 3));
1900 maskCount = maskCount & ~maskPrefix;
1901
1902 maskPrefix = parallelSuffix(maskCount);
1903 // Bits to move
1904 long maskMove5 = maskPrefix & mask;
1905 // Compress mask
1906 mask = (mask ^ maskMove5) | (maskMove5 >>> (1 << 4));
1907 maskCount = maskCount & ~maskPrefix;
1908
1909 maskPrefix = parallelSuffix(maskCount);
1910 // Bits to move
1911 long maskMove6 = maskPrefix & mask;
1912
1913 long t = i << (1 << 5);
1914 i = (i & ~maskMove6) | (t & maskMove6);
1915 t = i << (1 << 4);
1916 i = (i & ~maskMove5) | (t & maskMove5);
1917 t = i << (1 << 3);
1918 i = (i & ~maskMove4) | (t & maskMove4);
1919 t = i << (1 << 2);
1920 i = (i & ~maskMove3) | (t & maskMove3);
1921 t = i << (1 << 1);
1922 i = (i & ~maskMove2) | (t & maskMove2);
1923 t = i << (1 << 0);
1924 i = (i & ~maskMove1) | (t & maskMove1);
1925
1926 // Clear irrelevant bits
1927 return i & originalMask;
1928 }
1929
1930 @ForceInline
1931 private static long parallelSuffix(long maskCount) {
1932 long maskPrefix = maskCount ^ (maskCount << 1);
1933 maskPrefix = maskPrefix ^ (maskPrefix << 2);
1934 maskPrefix = maskPrefix ^ (maskPrefix << 4);
1935 maskPrefix = maskPrefix ^ (maskPrefix << 8);
1936 maskPrefix = maskPrefix ^ (maskPrefix << 16);
1937 maskPrefix = maskPrefix ^ (maskPrefix << 32);
1938 return maskPrefix;
1939 }
1940
1941 /**
1942 * Returns the signum function of the specified {@code long} value. (The
1943 * return value is -1 if the specified value is negative; 0 if the
1944 * specified value is zero; and 1 if the specified value is positive.)
1945 *
1946 * @param i the value whose signum is to be computed
1947 * @return the signum function of the specified {@code long} value.
1948 * @since 1.5
1949 */
1950 public static int signum(long i) {
1951 // HD, Section 2-7
1952 return (int) ((i >> 63) | (-i >>> 63));
1953 }
1954
1955 /**
1956 * Returns the value obtained by reversing the order of the bytes in the
1957 * two's complement representation of the specified {@code long} value.
1958 *
1959 * @param i the value whose bytes are to be reversed
1960 * @return the value obtained by reversing the bytes in the specified
1961 * {@code long} value.
1962 * @since 1.5
1963 */
1964 @IntrinsicCandidate
1965 public static long reverseBytes(long i) {
1966 i = (i & 0x00ff00ff00ff00ffL) << 8 | (i >>> 8) & 0x00ff00ff00ff00ffL;
1967 return (i << 48) | ((i & 0xffff0000L) << 16) |
1968 ((i >>> 16) & 0xffff0000L) | (i >>> 48);
1969 }
1970
1971 /**
1972 * Adds two {@code long} values together as per the + operator.
1973 *
1974 * @param a the first operand
1975 * @param b the second operand
1976 * @return the sum of {@code a} and {@code b}
1977 * @see java.util.function.BinaryOperator
1978 * @since 1.8
1979 */
1980 public static long sum(long a, long b) {
1981 return a + b;
1982 }
1983
1984 /**
1985 * Returns the greater of two {@code long} values
1986 * as if by calling {@link Math#max(long, long) Math.max}.
1987 *
1988 * @param a the first operand
1989 * @param b the second operand
1990 * @return the greater of {@code a} and {@code b}
1991 * @see java.util.function.BinaryOperator
1992 * @since 1.8
1993 */
1994 public static long max(long a, long b) {
1995 return Math.max(a, b);
1996 }
1997
1998 /**
1999 * Returns the smaller of two {@code long} values
2000 * as if by calling {@link Math#min(long, long) Math.min}.
2001 *
2002 * @param a the first operand
2003 * @param b the second operand
2004 * @return the smaller of {@code a} and {@code b}
2005 * @see java.util.function.BinaryOperator
2006 * @since 1.8
2007 */
2008 public static long min(long a, long b) {
2009 return Math.min(a, b);
2010 }
2011
2012 /**
2013 * Returns an {@link Optional} containing the nominal descriptor for this
2014 * instance, which is the instance itself.
2015 *
2016 * @return an {@link Optional} describing the {@linkplain Long} instance
2017 * @since 12
2018 */
2019 @Override
2020 public Optional<Long> describeConstable() {
2021 return Optional.of(this);
2022 }
2023
2024 /**
2025 * Resolves this instance as a {@link ConstantDesc}, the result of which is
2026 * the instance itself.
2027 *
2028 * @param lookup ignored
2029 * @return the {@linkplain Long} instance
2030 * @since 12
2031 */
2032 @Override
2033 public Long resolveConstantDesc(MethodHandles.Lookup lookup) {
2034 return this;
2035 }
2036
2037 /** use serialVersionUID from JDK 1.0.2 for interoperability */
2038 @java.io.Serial
2039 @Native private static final long serialVersionUID = 4290774380558885855L;
2040 }