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.util.DecimalDigits;
38 import jdk.internal.vm.annotation.ForceInline;
39 import jdk.internal.vm.annotation.IntrinsicCandidate;
40 import jdk.internal.vm.annotation.Stable;
41
42 import static java.lang.Character.digit;
43 import static java.lang.String.COMPACT_STRINGS;
44 import static java.lang.String.LATIN1;
45 import static java.lang.String.UTF16;
46
47 /**
48 * The {@code Long} class wraps a value of the primitive type {@code
49 * long} in an object. An object of type {@code Long} contains a
50 * single field whose type is {@code long}.
51 *
52 * <p> In addition, this class provides several methods for converting
53 * a {@code long} to a {@code String} and a {@code String} to a {@code
54 * long}, as well as other constants and methods useful when dealing
55 * with a {@code long}.
56 *
57 * <p>This is a <a href="{@docRoot}/java.base/java/lang/doc-files/ValueBased.html">value-based</a>
58 * class; programmers should treat instances that are
59 * {@linkplain #equals(Object) equal} as interchangeable and should not
60 * use instances for synchronization, or unpredictable behavior may
61 * occur. For example, in a future release, synchronization may fail.
62 *
63 * <p>Implementation note: The implementations of the "bit twiddling"
64 * methods (such as {@link #highestOneBit(long) highestOneBit} and
65 * {@link #numberOfTrailingZeros(long) numberOfTrailingZeros}) are
66 * based on material from Henry S. Warren, Jr.'s <i>Hacker's
67 * Delight</i>, (Addison Wesley, 2002).
68 *
69 * @author Lee Boynton
70 * @author Arthur van Hoff
71 * @author Josh Bloch
72 * @author Joseph D. Darcy
73 * @since 1.0
74 */
75 @jdk.internal.ValueBased
76 public final class Long extends Number
77 implements Comparable<Long>, Constable, ConstantDesc {
78 /**
79 * A constant holding the minimum value a {@code long} can
80 * have, -2<sup>63</sup>.
81 */
82 @Native public static final long MIN_VALUE = 0x8000000000000000L;
83
84 /**
85 * A constant holding the maximum value a {@code long} can
86 * have, 2<sup>63</sup>-1.
87 */
88 @Native public static final long MAX_VALUE = 0x7fffffffffffffffL;
89
90 /**
91 * The {@code Class} instance representing the primitive type
92 * {@code long}.
93 *
94 * @since 1.1
95 */
96 @SuppressWarnings("unchecked")
97 public static final Class<Long> TYPE = (Class<Long>) Class.getPrimitiveClass("long");
98
99 /**
100 * Returns a string representation of the first argument in the
101 * radix specified by the second argument.
102 *
103 * <p>If the radix is smaller than {@code Character.MIN_RADIX}
104 * or larger than {@code Character.MAX_RADIX}, then the radix
105 * {@code 10} is used instead.
106 *
107 * <p>If the first argument is negative, the first element of the
108 * result is the ASCII minus sign {@code '-'}
109 * ({@code '\u005Cu002d'}). If the first argument is not
110 * negative, no sign character appears in the result.
111 *
112 * <p>The remaining characters of the result represent the magnitude
113 * of the first argument. If the magnitude is zero, it is
114 * represented by a single zero character {@code '0'}
115 * ({@code '\u005Cu0030'}); otherwise, the first character of
116 * the representation of the magnitude will not be the zero
117 * character. The following ASCII characters are used as digits:
118 *
119 * <blockquote>
120 * {@code 0123456789abcdefghijklmnopqrstuvwxyz}
121 * </blockquote>
122 *
123 * These are {@code '\u005Cu0030'} through
124 * {@code '\u005Cu0039'} and {@code '\u005Cu0061'} through
125 * {@code '\u005Cu007a'}. If {@code radix} is
126 * <var>N</var>, then the first <var>N</var> of these characters
127 * are used as radix-<var>N</var> digits in the order shown. Thus,
128 * the digits for hexadecimal (radix 16) are
129 * {@code 0123456789abcdef}. If uppercase letters are
130 * desired, the {@link java.lang.String#toUpperCase()} method may
131 * be called on the result:
132 *
133 * <blockquote>
134 * {@code Long.toString(n, 16).toUpperCase()}
135 * </blockquote>
136 *
137 * @param i a {@code long} to be converted to a string.
138 * @param radix the radix to use in the string representation.
139 * @return a string representation of the argument in the specified radix.
140 * @see java.lang.Character#MAX_RADIX
141 * @see java.lang.Character#MIN_RADIX
142 */
143 public static String toString(long i, int radix) {
144 if (radix < Character.MIN_RADIX || radix > Character.MAX_RADIX)
145 radix = 10;
146 if (radix == 10)
147 return toString(i);
148
149 if (COMPACT_STRINGS) {
150 byte[] buf = new byte[65];
151 int charPos = 64;
152 boolean negative = (i < 0);
153
154 if (!negative) {
155 i = -i;
156 }
157
158 while (i <= -radix) {
159 buf[charPos--] = (byte)Integer.digits[(int)(-(i % radix))];
160 i = i / radix;
161 }
162 buf[charPos] = (byte)Integer.digits[(int)(-i)];
163
164 if (negative) {
165 buf[--charPos] = '-';
166 }
167 return StringLatin1.newString(buf, charPos, (65 - charPos));
168 }
169 return toStringUTF16(i, radix);
170 }
171
172 private static String toStringUTF16(long i, int radix) {
173 byte[] buf = new byte[65 * 2];
174 int charPos = 64;
175 boolean negative = (i < 0);
176 if (!negative) {
177 i = -i;
178 }
179 while (i <= -radix) {
180 StringUTF16.putChar(buf, charPos--, Integer.digits[(int)(-(i % radix))]);
181 i = i / radix;
182 }
183 StringUTF16.putChar(buf, charPos, Integer.digits[(int)(-i)]);
184 if (negative) {
185 StringUTF16.putChar(buf, --charPos, '-');
186 }
187 return StringUTF16.newString(buf, charPos, (65 - charPos));
188 }
189
190 /**
191 * Returns a string representation of the first argument as an
192 * unsigned integer value in the radix specified by the second
193 * argument.
194 *
195 * <p>If the radix is smaller than {@code Character.MIN_RADIX}
196 * or larger than {@code Character.MAX_RADIX}, then the radix
197 * {@code 10} is used instead.
198 *
199 * <p>Note that since the first argument is treated as an unsigned
200 * value, no leading sign character is printed.
201 *
202 * <p>If the magnitude is zero, it is represented by a single zero
203 * character {@code '0'} ({@code '\u005Cu0030'}); otherwise,
204 * the first character of the representation of the magnitude will
205 * not be the zero character.
206 *
207 * <p>The behavior of radixes and the characters used as digits
208 * are the same as {@link #toString(long, int) toString}.
209 *
210 * @param i an integer to be converted to an unsigned string.
211 * @param radix the radix to use in the string representation.
212 * @return an unsigned string representation of the argument in the specified radix.
213 * @see #toString(long, int)
214 * @since 1.8
215 */
216 public static String toUnsignedString(long i, int radix) {
217 if (i >= 0)
218 return toString(i, radix);
219 else {
220 return switch (radix) {
221 case 2 -> toBinaryString(i);
222 case 4 -> toUnsignedString0(i, 2);
223 case 8 -> toOctalString(i);
224 case 10 -> {
225 /*
226 * We can get the effect of an unsigned division by 10
227 * on a long value by first shifting right, yielding a
228 * positive value, and then dividing by 5. This
229 * allows the last digit and preceding digits to be
230 * isolated more quickly than by an initial conversion
231 * to BigInteger.
232 */
233 long quot = (i >>> 1) / 5;
234 long rem = i - quot * 10;
235 yield toString(quot) + rem;
236 }
237 case 16 -> toHexString(i);
238 case 32 -> toUnsignedString0(i, 5);
239 default -> toUnsignedBigInteger(i).toString(radix);
240 };
241 }
242 }
243
244 /**
245 * Return a BigInteger equal to the unsigned value of the
246 * argument.
247 */
248 private static BigInteger toUnsignedBigInteger(long i) {
249 if (i >= 0L)
250 return BigInteger.valueOf(i);
251 else {
252 int upper = (int) (i >>> 32);
253 int lower = (int) i;
254
255 // return (upper << 32) + lower
256 return (BigInteger.valueOf(Integer.toUnsignedLong(upper))).shiftLeft(32).
257 add(BigInteger.valueOf(Integer.toUnsignedLong(lower)));
258 }
259 }
260
261 /**
262 * Returns a string representation of the {@code long}
263 * argument as an unsigned integer in base 16.
264 *
265 * <p>The unsigned {@code long} value is the argument plus
266 * 2<sup>64</sup> if the argument is negative; otherwise, it is
267 * equal to the argument. This value is converted to a string of
268 * ASCII digits in hexadecimal (base 16) with no extra
269 * leading {@code 0}s.
270 *
271 * <p>The value of the argument can be recovered from the returned
272 * string {@code s} by calling {@link
273 * Long#parseUnsignedLong(String, int) Long.parseUnsignedLong(s,
274 * 16)}.
275 *
276 * <p>If the unsigned magnitude is zero, it is represented by a
277 * single zero character {@code '0'} ({@code '\u005Cu0030'});
278 * otherwise, the first character of the representation of the
279 * unsigned magnitude will not be the zero character. The
280 * following characters are used as hexadecimal digits:
281 *
282 * <blockquote>
283 * {@code 0123456789abcdef}
284 * </blockquote>
285 *
286 * These are the characters {@code '\u005Cu0030'} through
287 * {@code '\u005Cu0039'} and {@code '\u005Cu0061'} through
288 * {@code '\u005Cu0066'}. If uppercase letters are desired,
289 * the {@link java.lang.String#toUpperCase()} method may be called
290 * on the result:
291 *
292 * <blockquote>
293 * {@code Long.toHexString(n).toUpperCase()}
294 * </blockquote>
295 *
296 * @apiNote
297 * The {@link java.util.HexFormat} class provides formatting and parsing
298 * of byte arrays and primitives to return a string or adding to an {@link Appendable}.
299 * {@code HexFormat} formats and parses uppercase or lowercase hexadecimal characters,
300 * with leading zeros and for byte arrays includes for each byte
301 * a delimiter, prefix, and suffix.
302 *
303 * @param i a {@code long} to be converted to a string.
304 * @return the string representation of the unsigned {@code long}
305 * value represented by the argument in hexadecimal
306 * (base 16).
307 * @see java.util.HexFormat
308 * @see #parseUnsignedLong(String, int)
309 * @see #toUnsignedString(long, int)
310 * @since 1.0.2
311 */
312 public static String toHexString(long i) {
313 return toUnsignedString0(i, 4);
314 }
315
316 /**
317 * Returns a string representation of the {@code long}
318 * argument as an unsigned integer in base 8.
319 *
320 * <p>The unsigned {@code long} value is the argument plus
321 * 2<sup>64</sup> if the argument is negative; otherwise, it is
322 * equal to the argument. This value is converted to a string of
323 * ASCII digits in octal (base 8) with no extra leading
324 * {@code 0}s.
325 *
326 * <p>The value of the argument can be recovered from the returned
327 * string {@code s} by calling {@link
328 * Long#parseUnsignedLong(String, int) Long.parseUnsignedLong(s,
329 * 8)}.
330 *
331 * <p>If the unsigned magnitude is zero, it is represented by a
332 * single zero character {@code '0'} ({@code '\u005Cu0030'});
333 * otherwise, the first character of the representation of the
334 * unsigned magnitude will not be the zero character. The
335 * following characters are used as octal digits:
336 *
337 * <blockquote>
338 * {@code 01234567}
339 * </blockquote>
340 *
341 * These are the characters {@code '\u005Cu0030'} through
342 * {@code '\u005Cu0037'}.
343 *
344 * @param i a {@code long} to be converted to a string.
345 * @return the string representation of the unsigned {@code long}
346 * value represented by the argument in octal (base 8).
347 * @see #parseUnsignedLong(String, int)
348 * @see #toUnsignedString(long, int)
349 * @since 1.0.2
350 */
351 public static String toOctalString(long i) {
352 return toUnsignedString0(i, 3);
353 }
354
355 /**
356 * Returns a string representation of the {@code long}
357 * argument as an unsigned integer in base 2.
358 *
359 * <p>The unsigned {@code long} value is the argument plus
360 * 2<sup>64</sup> if the argument is negative; otherwise, it is
361 * equal to the argument. This value is converted to a string of
362 * ASCII digits in binary (base 2) with no extra leading
363 * {@code 0}s.
364 *
365 * <p>The value of the argument can be recovered from the returned
366 * string {@code s} by calling {@link
367 * Long#parseUnsignedLong(String, int) Long.parseUnsignedLong(s,
368 * 2)}.
369 *
370 * <p>If the unsigned magnitude is zero, it is represented by a
371 * single zero character {@code '0'} ({@code '\u005Cu0030'});
372 * otherwise, the first character of the representation of the
373 * unsigned magnitude will not be the zero character. The
374 * characters {@code '0'} ({@code '\u005Cu0030'}) and {@code
375 * '1'} ({@code '\u005Cu0031'}) are used as binary digits.
376 *
377 * @param i a {@code long} to be converted to a string.
378 * @return the string representation of the unsigned {@code long}
379 * value represented by the argument in binary (base 2).
380 * @see #parseUnsignedLong(String, int)
381 * @see #toUnsignedString(long, int)
382 * @since 1.0.2
383 */
384 public static String toBinaryString(long i) {
385 return toUnsignedString0(i, 1);
386 }
387
388 /**
389 * Format a long (treated as unsigned) into a String.
390 * @param val the value to format
391 * @param shift the log2 of the base to format in (4 for hex, 3 for octal, 1 for binary)
392 */
393 static String toUnsignedString0(long val, int shift) {
394 // assert shift > 0 && shift <=5 : "Illegal shift value";
395 int mag = Long.SIZE - Long.numberOfLeadingZeros(val);
396 int chars = Math.max(((mag + (shift - 1)) / shift), 1);
397 if (COMPACT_STRINGS) {
398 byte[] buf = new byte[chars];
399 formatUnsignedLong0(val, shift, buf, 0, chars);
400 return new String(buf, LATIN1);
401 } else {
402 byte[] buf = new byte[chars * 2];
403 formatUnsignedLong0UTF16(val, shift, buf, 0, chars);
404 return new String(buf, UTF16);
405 }
406 }
407
408 /**
409 * Format a long (treated as unsigned) into a byte buffer (LATIN1 version). If
410 * {@code len} exceeds the formatted ASCII representation of {@code val},
411 * {@code buf} will be padded with leading zeroes.
412 *
413 * @param val the unsigned long to format
414 * @param shift the log2 of the base to format in (4 for hex, 3 for octal, 1 for binary)
415 * @param buf the byte buffer to write to
416 * @param offset the offset in the destination buffer to start at
417 * @param len the number of characters to write
418 */
419 private static void formatUnsignedLong0(long val, int shift, byte[] buf, int offset, int len) {
420 int charPos = offset + len;
421 int radix = 1 << shift;
422 int mask = radix - 1;
423 do {
424 buf[--charPos] = (byte)Integer.digits[((int) val) & mask];
425 val >>>= shift;
426 } while (charPos > offset);
427 }
428
429 /**
430 * Format a long (treated as unsigned) into a byte buffer (UTF16 version). If
431 * {@code len} exceeds the formatted ASCII representation of {@code val},
432 * {@code buf} will be padded with leading zeroes.
433 *
434 * @param val the unsigned long to format
435 * @param shift the log2 of the base to format in (4 for hex, 3 for octal, 1 for binary)
436 * @param buf the byte buffer to write to
437 * @param offset the offset in the destination buffer to start at
438 * @param len the number of characters to write
439 */
440 private static void formatUnsignedLong0UTF16(long val, int shift, byte[] buf, int offset, int len) {
441 int charPos = offset + len;
442 int radix = 1 << shift;
443 int mask = radix - 1;
444 do {
445 StringUTF16.putChar(buf, --charPos, Integer.digits[((int) val) & mask]);
446 val >>>= shift;
447 } while (charPos > offset);
448 }
449
450 /**
451 * Returns a {@code String} object representing the specified
452 * {@code long}. The argument is converted to signed decimal
453 * representation and returned as a string, exactly as if the
454 * argument and the radix 10 were given as arguments to the {@link
455 * #toString(long, int)} method.
456 *
457 * @param i a {@code long} to be converted.
458 * @return a string representation of the argument in base 10.
459 */
460 public static String toString(long i) {
461 int size = DecimalDigits.stringSize(i);
462 if (COMPACT_STRINGS) {
463 byte[] buf = new byte[size];
464 StringLatin1.getChars(i, size, buf);
465 return new String(buf, LATIN1);
466 } else {
467 byte[] buf = new byte[size * 2];
468 StringUTF16.getChars(i, size, buf);
469 return new String(buf, UTF16);
470 }
471 }
472
473 /**
474 * Returns a string representation of the argument as an unsigned
475 * decimal value.
476 *
477 * The argument is converted to unsigned decimal representation
478 * and returned as a string exactly as if the argument and radix
479 * 10 were given as arguments to the {@link #toUnsignedString(long,
480 * int)} method.
481 *
482 * @param i an integer to be converted to an unsigned string.
483 * @return an unsigned string representation of the argument.
484 * @see #toUnsignedString(long, int)
485 * @since 1.8
486 */
487 public static String toUnsignedString(long i) {
488 return toUnsignedString(i, 10);
489 }
490
491 /**
492 * Parses the string argument as a signed {@code long} in the
493 * radix specified by the second argument. The characters in the
494 * string must all be digits of the specified radix (as determined
495 * by whether {@link java.lang.Character#digit(char, int)} returns
496 * a nonnegative value), except that the first character may be an
497 * ASCII minus sign {@code '-'} ({@code '\u005Cu002D'}) to
498 * indicate a negative value or an ASCII plus sign {@code '+'}
499 * ({@code '\u005Cu002B'}) to indicate a positive value. The
500 * resulting {@code long} value is returned.
501 *
502 * <p>Note that neither the character {@code L}
503 * ({@code '\u005Cu004C'}) nor {@code l}
504 * ({@code '\u005Cu006C'}) is permitted to appear at the end
505 * of the string as a type indicator, as would be permitted in
506 * Java programming language source code - except that either
507 * {@code L} or {@code l} may appear as a digit for a
508 * radix greater than or equal to 22.
509 *
510 * <p>An exception of type {@code NumberFormatException} is
511 * thrown if any of the following situations occurs:
512 * <ul>
513 *
514 * <li>The first argument is {@code null} or is a string of
515 * length zero.
516 *
517 * <li>The {@code radix} is either smaller than {@link
518 * java.lang.Character#MIN_RADIX} or larger than {@link
519 * java.lang.Character#MAX_RADIX}.
520 *
521 * <li>Any character of the string is not a digit of the specified
522 * radix, except that the first character may be a minus sign
523 * {@code '-'} ({@code '\u005Cu002d'}) or plus sign {@code
524 * '+'} ({@code '\u005Cu002B'}) provided that the string is
525 * longer than length 1.
526 *
527 * <li>The value represented by the string is not a value of type
528 * {@code long}.
529 * </ul>
530 *
531 * <p>Examples:
532 * <blockquote><pre>
533 * parseLong("0", 10) returns 0L
534 * parseLong("473", 10) returns 473L
535 * parseLong("+42", 10) returns 42L
536 * parseLong("-0", 10) returns 0L
537 * parseLong("-FF", 16) returns -255L
538 * parseLong("1100110", 2) returns 102L
539 * parseLong("99", 8) throws a NumberFormatException
540 * parseLong("Hazelnut", 10) throws a NumberFormatException
541 * parseLong("Hazelnut", 36) returns 1356099454469L
542 * </pre></blockquote>
543 *
544 * @param s the {@code String} containing the
545 * {@code long} representation to be parsed.
546 * @param radix the radix to be used while parsing {@code s}.
547 * @return the {@code long} represented by the string argument in
548 * the specified radix.
549 * @throws NumberFormatException if the string does not contain a
550 * parsable {@code long}.
551 */
552 public static long parseLong(String s, int radix)
553 throws NumberFormatException {
554 if (s == null) {
555 throw new NumberFormatException("Cannot parse null string");
556 }
557
558 if (radix < Character.MIN_RADIX) {
559 throw new NumberFormatException(String.format(
560 "radix %s less than Character.MIN_RADIX", radix));
561 }
562
563 if (radix > Character.MAX_RADIX) {
564 throw new NumberFormatException(String.format(
565 "radix %s greater than Character.MAX_RADIX", radix));
566 }
567
568 int len = s.length();
569 if (len == 0) {
570 throw NumberFormatException.forInputString("", radix);
571 }
572 int digit = ~0xFF;
573 int i = 0;
574 char firstChar = s.charAt(i++);
575 if (firstChar != '-' && firstChar != '+') {
576 digit = digit(firstChar, radix);
577 }
578 if (digit >= 0 || digit == ~0xFF && len > 1) {
579 long limit = firstChar != '-' ? MIN_VALUE + 1 : MIN_VALUE;
580 long multmin = limit / radix;
581 long result = -(digit & 0xFF);
582 boolean inRange = true;
583 /* Accumulating negatively avoids surprises near MAX_VALUE */
584 while (i < len && (digit = digit(s.charAt(i++), radix)) >= 0
585 && (inRange = result > multmin
586 || result == multmin && digit <= (int) (radix * multmin - limit))) {
587 result = radix * result - digit;
588 }
589 if (inRange && i == len && digit >= 0) {
590 return firstChar != '-' ? -result : result;
591 }
592 }
593 throw NumberFormatException.forInputString(s, radix);
594 }
595
596 /**
597 * Parses the {@link CharSequence} argument as a signed {@code long} in
598 * the specified {@code radix}, beginning at the specified
599 * {@code beginIndex} and extending to {@code endIndex - 1}.
600 *
601 * <p>The method does not take steps to guard against the
602 * {@code CharSequence} being mutated while parsing.
603 *
604 * @param s the {@code CharSequence} containing the {@code long}
605 * representation to be parsed
606 * @param beginIndex the beginning index, inclusive.
607 * @param endIndex the ending index, exclusive.
608 * @param radix the radix to be used while parsing {@code s}.
609 * @return the signed {@code long} represented by the subsequence in
610 * the specified radix.
611 * @throws NullPointerException if {@code s} is null.
612 * @throws IndexOutOfBoundsException if {@code beginIndex} is
613 * negative, or if {@code beginIndex} is greater than
614 * {@code endIndex} or if {@code endIndex} is greater than
615 * {@code s.length()}.
616 * @throws NumberFormatException if the {@code CharSequence} does not
617 * contain a parsable {@code long} in the specified
618 * {@code radix}, or if {@code radix} is either smaller than
619 * {@link java.lang.Character#MIN_RADIX} or larger than
620 * {@link java.lang.Character#MAX_RADIX}.
621 * @since 9
622 */
623 public static long parseLong(CharSequence s, int beginIndex, int endIndex, int radix)
624 throws NumberFormatException {
625 Objects.requireNonNull(s);
626 Objects.checkFromToIndex(beginIndex, endIndex, s.length());
627
628 if (radix < Character.MIN_RADIX) {
629 throw new NumberFormatException(String.format(
630 "radix %s less than Character.MIN_RADIX", radix));
631 }
632
633 if (radix > Character.MAX_RADIX) {
634 throw new NumberFormatException(String.format(
635 "radix %s greater than Character.MAX_RADIX", radix));
636 }
637
638 /*
639 * While s can be concurrently modified, it is ensured that each
640 * of its characters is read at most once, from lower to higher indices.
641 * This is obtained by reading them using the pattern s.charAt(i++),
642 * and by not updating i anywhere else.
643 */
644 if (beginIndex == endIndex) {
645 throw NumberFormatException.forInputString("", radix);
646 }
647 int digit = ~0xFF; // ~0xFF means firstChar char is sign
648 int i = beginIndex;
649 char firstChar = s.charAt(i++);
650 if (firstChar != '-' && firstChar != '+') {
651 digit = digit(firstChar, radix);
652 }
653 if (digit >= 0 || digit == ~0xFF && endIndex - beginIndex > 1) {
654 long limit = firstChar != '-' ? MIN_VALUE + 1 : MIN_VALUE;
655 long multmin = limit / radix;
656 long result = -(digit & 0xFF);
657 boolean inRange = true;
658 /* Accumulating negatively avoids surprises near MAX_VALUE */
659 while (i < endIndex && (digit = digit(s.charAt(i++), radix)) >= 0
660 && (inRange = result > multmin
661 || result == multmin && digit <= (int) (radix * multmin - limit))) {
662 result = radix * result - digit;
663 }
664 if (inRange && i == endIndex && digit >= 0) {
665 return firstChar != '-' ? -result : result;
666 }
667 }
668 throw NumberFormatException.forCharSequence(s, beginIndex,
669 endIndex, i - (digit < -1 ? 0 : 1));
670 }
671
672 /**
673 * Parses the string argument as a signed decimal {@code long}.
674 * The characters in the string must all be decimal digits, except
675 * that the first character may be an ASCII minus sign {@code '-'}
676 * ({@code \u005Cu002D'}) to indicate a negative value or an
677 * ASCII plus sign {@code '+'} ({@code '\u005Cu002B'}) to
678 * indicate a positive value. The resulting {@code long} value is
679 * returned, exactly as if the argument and the radix {@code 10}
680 * were given as arguments to the {@link
681 * #parseLong(java.lang.String, int)} method.
682 *
683 * <p>Note that neither the character {@code L}
684 * ({@code '\u005Cu004C'}) nor {@code l}
685 * ({@code '\u005Cu006C'}) is permitted to appear at the end
686 * of the string as a type indicator, as would be permitted in
687 * Java programming language source code.
688 *
689 * @param s a {@code String} containing the {@code long}
690 * representation to be parsed
691 * @return the {@code long} represented by the argument in
692 * decimal.
693 * @throws NumberFormatException if the string does not contain a
694 * parsable {@code long}.
695 */
696 public static long parseLong(String s) throws NumberFormatException {
697 return parseLong(s, 10);
698 }
699
700 /**
701 * Parses the string argument as an unsigned {@code long} in the
702 * radix specified by the second argument. An unsigned integer
703 * maps the values usually associated with negative numbers to
704 * positive numbers larger than {@code MAX_VALUE}.
705 *
706 * The characters in the string must all be digits of the
707 * specified radix (as determined by whether {@link
708 * java.lang.Character#digit(char, int)} returns a nonnegative
709 * value), except that the first character may be an ASCII plus
710 * sign {@code '+'} ({@code '\u005Cu002B'}). The resulting
711 * integer value is returned.
712 *
713 * <p>An exception of type {@code NumberFormatException} is
714 * thrown if any of the following situations occurs:
715 * <ul>
716 * <li>The first argument is {@code null} or is a string of
717 * length zero.
718 *
719 * <li>The radix is either smaller than
720 * {@link java.lang.Character#MIN_RADIX} or
721 * larger than {@link java.lang.Character#MAX_RADIX}.
722 *
723 * <li>Any character of the string is not a digit of the specified
724 * radix, except that the first character may be a plus sign
725 * {@code '+'} ({@code '\u005Cu002B'}) provided that the
726 * string is longer than length 1.
727 *
728 * <li>The value represented by the string is larger than the
729 * largest unsigned {@code long}, 2<sup>64</sup>-1.
730 *
731 * </ul>
732 *
733 *
734 * @param s the {@code String} containing the unsigned integer
735 * representation to be parsed
736 * @param radix the radix to be used while parsing {@code s}.
737 * @return the unsigned {@code long} represented by the string
738 * argument in the specified radix.
739 * @throws NumberFormatException if the {@code String}
740 * does not contain a parsable {@code long}.
741 * @since 1.8
742 */
743 public static long parseUnsignedLong(String s, int radix)
744 throws NumberFormatException {
745 if (s == null) {
746 throw new NumberFormatException("Cannot parse null string");
747 }
748
749 if (radix < Character.MIN_RADIX) {
750 throw new NumberFormatException(String.format(
751 "radix %s less than Character.MIN_RADIX", radix));
752 }
753
754 if (radix > Character.MAX_RADIX) {
755 throw new NumberFormatException(String.format(
756 "radix %s greater than Character.MAX_RADIX", radix));
757 }
758
759 int len = s.length();
760 if (len == 0) {
761 throw NumberFormatException.forInputString(s, radix);
762 }
763 int i = 0;
764 char firstChar = s.charAt(i++);
765 if (firstChar == '-') {
766 throw new NumberFormatException(String.format(
767 "Illegal leading minus sign on unsigned string %s.", s));
768 }
769 int digit = ~0xFF;
770 if (firstChar != '+') {
771 digit = digit(firstChar, radix);
772 }
773 if (digit >= 0 || digit == ~0xFF && len > 1) {
774 long multmax = divideUnsigned(-1L, radix); // -1L is max unsigned long
775 long result = digit & 0xFF;
776 boolean inRange = true;
777 while (i < len && (digit = digit(s.charAt(i++), radix)) >= 0
778 && (inRange = compareUnsigned(result, multmax) < 0
779 || result == multmax && digit < (int) (-radix * multmax))) {
780 result = radix * result + digit;
781 }
782 if (inRange && i == len && digit >= 0) {
783 return result;
784 }
785 }
786 if (digit < 0) {
787 throw NumberFormatException.forInputString(s, radix);
788 }
789 throw new NumberFormatException(String.format(
790 "String value %s exceeds range of unsigned long.", s));
791 }
792
793 /**
794 * Parses the {@link CharSequence} argument as an unsigned {@code long} in
795 * the specified {@code radix}, beginning at the specified
796 * {@code beginIndex} and extending to {@code endIndex - 1}.
797 *
798 * <p>The method does not take steps to guard against the
799 * {@code CharSequence} being mutated while parsing.
800 *
801 * @param s the {@code CharSequence} containing the unsigned
802 * {@code long} representation to be parsed
803 * @param beginIndex the beginning index, inclusive.
804 * @param endIndex the ending index, exclusive.
805 * @param radix the radix to be used while parsing {@code s}.
806 * @return the unsigned {@code long} represented by the subsequence in
807 * the specified radix.
808 * @throws NullPointerException if {@code s} is null.
809 * @throws IndexOutOfBoundsException if {@code beginIndex} is
810 * negative, or if {@code beginIndex} is greater than
811 * {@code endIndex} or if {@code endIndex} is greater than
812 * {@code s.length()}.
813 * @throws NumberFormatException if the {@code CharSequence} does not
814 * contain a parsable unsigned {@code long} in the specified
815 * {@code radix}, or if {@code radix} is either smaller than
816 * {@link java.lang.Character#MIN_RADIX} or larger than
817 * {@link java.lang.Character#MAX_RADIX}.
818 * @since 9
819 */
820 public static long parseUnsignedLong(CharSequence s, int beginIndex, int endIndex, int radix)
821 throws NumberFormatException {
822 Objects.requireNonNull(s);
823 Objects.checkFromToIndex(beginIndex, endIndex, s.length());
824
825 if (radix < Character.MIN_RADIX) {
826 throw new NumberFormatException(String.format(
827 "radix %s less than Character.MIN_RADIX", radix));
828 }
829
830 if (radix > Character.MAX_RADIX) {
831 throw new NumberFormatException(String.format(
832 "radix %s greater than Character.MAX_RADIX", radix));
833 }
834
835 /*
836 * While s can be concurrently modified, it is ensured that each
837 * of its characters is read at most once, from lower to higher indices.
838 * This is obtained by reading them using the pattern s.charAt(i++),
839 * and by not updating i anywhere else.
840 */
841 if (beginIndex == endIndex) {
842 throw NumberFormatException.forInputString("", radix);
843 }
844 int i = beginIndex;
845 char firstChar = s.charAt(i++);
846 if (firstChar == '-') {
847 throw new NumberFormatException(
848 "Illegal leading minus sign on unsigned string " + s + ".");
849 }
850 int digit = ~0xFF;
851 if (firstChar != '+') {
852 digit = digit(firstChar, radix);
853 }
854 if (digit >= 0 || digit == ~0xFF && endIndex - beginIndex > 1) {
855 long multmax = divideUnsigned(-1L, radix); // -1L is max unsigned long
856 long result = digit & 0xFF;
857 boolean inRange = true;
858 while (i < endIndex && (digit = digit(s.charAt(i++), radix)) >= 0
859 && (inRange = compareUnsigned(result, multmax) < 0
860 || result == multmax && digit < (int) (-radix * multmax))) {
861 result = radix * result + digit;
862 }
863 if (inRange && i == endIndex && digit >= 0) {
864 return result;
865 }
866 }
867 if (digit < 0) {
868 throw NumberFormatException.forCharSequence(s, beginIndex,
869 endIndex, i - (digit < -1 ? 0 : 1));
870 }
871 throw new NumberFormatException(String.format(
872 "String value %s exceeds range of unsigned long.", s));
873 }
874
875 /**
876 * Parses the string argument as an unsigned decimal {@code long}. The
877 * characters in the string must all be decimal digits, except
878 * that the first character may be an ASCII plus sign {@code
879 * '+'} ({@code '\u005Cu002B'}). The resulting integer value
880 * is returned, exactly as if the argument and the radix 10 were
881 * given as arguments to the {@link
882 * #parseUnsignedLong(java.lang.String, int)} method.
883 *
884 * @param s a {@code String} containing the unsigned {@code long}
885 * representation to be parsed
886 * @return the unsigned {@code long} value represented by the decimal string argument
887 * @throws NumberFormatException if the string does not contain a
888 * parsable unsigned integer.
889 * @since 1.8
890 */
891 public static long parseUnsignedLong(String s) throws NumberFormatException {
892 return parseUnsignedLong(s, 10);
893 }
894
895 /**
896 * Returns a {@code Long} object holding the value
897 * extracted from the specified {@code String} when parsed
898 * with the radix given by the second argument. The first
899 * argument is interpreted as representing a signed
900 * {@code long} in the radix specified by the second
901 * argument, exactly as if the arguments were given to the {@link
902 * #parseLong(java.lang.String, int)} method. The result is a
903 * {@code Long} object that represents the {@code long}
904 * value specified by the string.
905 *
906 * <p>In other words, this method returns a {@code Long} object equal
907 * to the value of:
908 *
909 * <blockquote>
910 * {@code Long.valueOf(Long.parseLong(s, radix))}
911 * </blockquote>
912 *
913 * @param s the string to be parsed
914 * @param radix the radix to be used in interpreting {@code s}
915 * @return a {@code Long} object holding the value
916 * represented by the string argument in the specified
917 * radix.
918 * @throws NumberFormatException If the {@code String} does not
919 * contain a parsable {@code long}.
920 */
921 public static Long valueOf(String s, int radix) throws NumberFormatException {
922 return Long.valueOf(parseLong(s, radix));
923 }
924
925 /**
926 * Returns a {@code Long} object holding the value
927 * of the specified {@code String}. The argument is
928 * interpreted as representing a signed decimal {@code long},
929 * exactly as if the argument were given to the {@link
930 * #parseLong(java.lang.String)} method. The result is a
931 * {@code Long} object that represents the integer value
932 * specified by the string.
933 *
934 * <p>In other words, this method returns a {@code Long} object
935 * equal to the value of:
936 *
937 * <blockquote>
938 * {@code Long.valueOf(Long.parseLong(s))}
939 * </blockquote>
940 *
941 * @param s the string to be parsed.
942 * @return a {@code Long} object holding the value
943 * represented by the string argument.
944 * @throws NumberFormatException If the string cannot be parsed
945 * as a {@code long}.
946 */
947 public static Long valueOf(String s) throws NumberFormatException
948 {
949 return Long.valueOf(parseLong(s, 10));
950 }
951
952 private static final class LongCache {
953 private LongCache() {}
954
955 @Stable
956 static final Long[] cache;
957 static Long[] archivedCache;
958
959 static {
960 int size = -(-128) + 127 + 1;
961
962 // Load and use the archived cache if it exists
963 CDS.initializeFromArchive(LongCache.class);
964 if (archivedCache == null || archivedCache.length != size) {
965 Long[] c = new Long[size];
966 long value = -128;
967 for(int i = 0; i < size; i++) {
968 c[i] = new Long(value++);
969 }
970 archivedCache = c;
971 }
972 cache = archivedCache;
973 }
974 }
975
976 /**
977 * Returns a {@code Long} instance representing the specified
978 * {@code long} value.
979 * If a new {@code Long} instance is not required, this method
980 * should generally be used in preference to the constructor
981 * {@link #Long(long)}, as this method is likely to yield
982 * significantly better space and time performance by caching
983 * frequently requested values.
984 *
985 * This method will always cache values in the range -128 to 127,
986 * inclusive, and may cache other values outside of this range.
987 *
988 * @param l a long value.
989 * @return a {@code Long} instance representing {@code l}.
990 * @since 1.5
991 */
992 @IntrinsicCandidate
993 public static Long valueOf(long l) {
994 final int offset = 128;
995 if (l >= -128 && l <= 127) { // will cache
996 return LongCache.cache[(int)l + offset];
997 }
998 return new Long(l);
999 }
1000
1001 /**
1002 * Decodes a {@code String} into a {@code Long}.
1003 * Accepts decimal, hexadecimal, and octal numbers given by the
1004 * following grammar:
1005 *
1006 * <blockquote>
1007 * <dl>
1008 * <dt><i>DecodableString:</i>
1009 * <dd><i>Sign<sub>opt</sub> DecimalNumeral</i>
1010 * <dd><i>Sign<sub>opt</sub></i> {@code 0x} <i>HexDigits</i>
1011 * <dd><i>Sign<sub>opt</sub></i> {@code 0X} <i>HexDigits</i>
1012 * <dd><i>Sign<sub>opt</sub></i> {@code #} <i>HexDigits</i>
1013 * <dd><i>Sign<sub>opt</sub></i> {@code 0} <i>OctalDigits</i>
1014 *
1015 * <dt><i>Sign:</i>
1016 * <dd>{@code -}
1017 * <dd>{@code +}
1018 * </dl>
1019 * </blockquote>
1020 *
1021 * <i>DecimalNumeral</i>, <i>HexDigits</i>, and <i>OctalDigits</i>
1022 * are as defined in section {@jls 3.10.1} of
1023 * <cite>The Java Language Specification</cite>,
1024 * except that underscores are not accepted between digits.
1025 *
1026 * <p>The sequence of characters following an optional
1027 * sign and/or radix specifier ("{@code 0x}", "{@code 0X}",
1028 * "{@code #}", or leading zero) is parsed as by the {@code
1029 * Long.parseLong} method with the indicated radix (10, 16, or 8).
1030 * This sequence of characters must represent a positive value or
1031 * a {@link NumberFormatException} will be thrown. The result is
1032 * negated if first character of the specified {@code String} is
1033 * the minus sign. No whitespace characters are permitted in the
1034 * {@code String}.
1035 *
1036 * @param nm the {@code String} to decode.
1037 * @return a {@code Long} object holding the {@code long}
1038 * value represented by {@code nm}
1039 * @throws NumberFormatException if the {@code String} does not
1040 * contain a parsable {@code long}.
1041 * @see java.lang.Long#parseLong(String, int)
1042 * @since 1.2
1043 */
1044 public static Long decode(String nm) throws NumberFormatException {
1045 int radix = 10;
1046 int index = 0;
1047 boolean negative = false;
1048 long result;
1049
1050 if (nm.isEmpty())
1051 throw new NumberFormatException("Zero length string");
1052 char firstChar = nm.charAt(0);
1053 // Handle sign, if present
1054 if (firstChar == '-') {
1055 negative = true;
1056 index++;
1057 } else if (firstChar == '+')
1058 index++;
1059
1060 // Handle radix specifier, if present
1061 if (nm.startsWith("0x", index) || nm.startsWith("0X", index)) {
1062 index += 2;
1063 radix = 16;
1064 }
1065 else if (nm.startsWith("#", index)) {
1066 index ++;
1067 radix = 16;
1068 }
1069 else if (nm.startsWith("0", index) && nm.length() > 1 + index) {
1070 index ++;
1071 radix = 8;
1072 }
1073
1074 if (nm.startsWith("-", index) || nm.startsWith("+", index))
1075 throw new NumberFormatException("Sign character in wrong position");
1076
1077 try {
1078 result = parseLong(nm, index, nm.length(), radix);
1079 result = negative ? -result : result;
1080 } catch (NumberFormatException e) {
1081 // If number is Long.MIN_VALUE, we'll end up here. The next line
1082 // handles this case, and causes any genuine format error to be
1083 // rethrown.
1084 String constant = negative ? ("-" + nm.substring(index))
1085 : nm.substring(index);
1086 result = parseLong(constant, radix);
1087 }
1088 return result;
1089 }
1090
1091 /**
1092 * The value of the {@code Long}.
1093 *
1094 * @serial
1095 */
1096 private final long value;
1097
1098 /**
1099 * Constructs a newly allocated {@code Long} object that
1100 * represents the specified {@code long} argument.
1101 *
1102 * @param value the value to be represented by the
1103 * {@code Long} object.
1104 *
1105 * @deprecated
1106 * It is rarely appropriate to use this constructor. The static factory
1107 * {@link #valueOf(long)} is generally a better choice, as it is
1108 * likely to yield significantly better space and time performance.
1109 */
1110 @Deprecated(since="9", forRemoval = true)
1111 public Long(long value) {
1112 this.value = value;
1113 }
1114
1115 /**
1116 * Constructs a newly allocated {@code Long} object that
1117 * represents the {@code long} value indicated by the
1118 * {@code String} parameter. The string is converted to a
1119 * {@code long} value in exactly the manner used by the
1120 * {@code parseLong} method for radix 10.
1121 *
1122 * @param s the {@code String} to be converted to a
1123 * {@code Long}.
1124 * @throws NumberFormatException if the {@code String} does not
1125 * contain a parsable {@code long}.
1126 *
1127 * @deprecated
1128 * It is rarely appropriate to use this constructor.
1129 * Use {@link #parseLong(String)} to convert a string to a
1130 * {@code long} primitive, or use {@link #valueOf(String)}
1131 * to convert a string to a {@code Long} object.
1132 */
1133 @Deprecated(since="9", forRemoval = true)
1134 public Long(String s) throws NumberFormatException {
1135 this.value = parseLong(s, 10);
1136 }
1137
1138 /**
1139 * Returns the value of this {@code Long} as a {@code byte} after
1140 * a narrowing primitive conversion.
1141 * @jls 5.1.3 Narrowing Primitive Conversion
1142 */
1143 public byte byteValue() {
1144 return (byte)value;
1145 }
1146
1147 /**
1148 * Returns the value of this {@code Long} as a {@code short} after
1149 * a narrowing primitive conversion.
1150 * @jls 5.1.3 Narrowing Primitive Conversion
1151 */
1152 public short shortValue() {
1153 return (short)value;
1154 }
1155
1156 /**
1157 * Returns the value of this {@code Long} as an {@code int} after
1158 * a narrowing primitive conversion.
1159 * @jls 5.1.3 Narrowing Primitive Conversion
1160 */
1161 public int intValue() {
1162 return (int)value;
1163 }
1164
1165 /**
1166 * Returns the value of this {@code Long} as a
1167 * {@code long} value.
1168 */
1169 @IntrinsicCandidate
1170 public long longValue() {
1171 return value;
1172 }
1173
1174 /**
1175 * Returns the value of this {@code Long} as a {@code float} after
1176 * a widening primitive conversion.
1177 * @jls 5.1.2 Widening Primitive Conversion
1178 */
1179 public float floatValue() {
1180 return (float)value;
1181 }
1182
1183 /**
1184 * Returns the value of this {@code Long} as a {@code double}
1185 * after a widening primitive conversion.
1186 * @jls 5.1.2 Widening Primitive Conversion
1187 */
1188 public double doubleValue() {
1189 return (double)value;
1190 }
1191
1192 /**
1193 * Returns a {@code String} object representing this
1194 * {@code Long}'s value. The value is converted to signed
1195 * decimal representation and returned as a string, exactly as if
1196 * the {@code long} value were given as an argument to the
1197 * {@link java.lang.Long#toString(long)} method.
1198 *
1199 * @return a string representation of the value of this object in
1200 * base 10.
1201 */
1202 public String toString() {
1203 return toString(value);
1204 }
1205
1206 /**
1207 * Returns a hash code for this {@code Long}. The result is
1208 * the exclusive OR of the two halves of the primitive
1209 * {@code long} value held by this {@code Long}
1210 * object. That is, the hashcode is the value of the expression:
1211 *
1212 * <blockquote>
1213 * {@code (int)(this.longValue()^(this.longValue()>>>32))}
1214 * </blockquote>
1215 *
1216 * @return a hash code value for this object.
1217 */
1218 @Override
1219 public int hashCode() {
1220 return Long.hashCode(value);
1221 }
1222
1223 /**
1224 * Returns a hash code for a {@code long} value; compatible with
1225 * {@code Long.hashCode()}.
1226 *
1227 * @param value the value to hash
1228 * @return a hash code value for a {@code long} value.
1229 * @since 1.8
1230 */
1231 public static int hashCode(long value) {
1232 return (int)(value ^ (value >>> 32));
1233 }
1234
1235 /**
1236 * Compares this object to the specified object. The result is
1237 * {@code true} if and only if the argument is not
1238 * {@code null} and is a {@code Long} object that
1239 * contains the same {@code long} value as this object.
1240 *
1241 * @param obj the object to compare with.
1242 * @return {@code true} if the objects are the same;
1243 * {@code false} otherwise.
1244 */
1245 public boolean equals(Object obj) {
1246 if (obj instanceof Long) {
1247 return value == ((Long)obj).longValue();
1248 }
1249 return false;
1250 }
1251
1252 /**
1253 * Determines the {@code long} value of the system property
1254 * with the specified name.
1255 *
1256 * <p>The first argument is treated as the name of a system
1257 * property. System properties are accessible through the {@link
1258 * java.lang.System#getProperty(java.lang.String)} method. The
1259 * string value of this property is then interpreted as a {@code
1260 * long} value using the grammar supported by {@link Long#decode decode}
1261 * and a {@code Long} object representing this value is returned.
1262 *
1263 * <p>If there is no property with the specified name, if the
1264 * specified name is empty or {@code null}, or if the property
1265 * does not have the correct numeric format, then {@code null} is
1266 * returned.
1267 *
1268 * <p>In other words, this method returns a {@code Long} object
1269 * equal to the value of:
1270 *
1271 * <blockquote>
1272 * {@code getLong(nm, null)}
1273 * </blockquote>
1274 *
1275 * @param nm property name.
1276 * @return the {@code Long} value of the property.
1277 * @throws SecurityException for the same reasons as
1278 * {@link System#getProperty(String) System.getProperty}
1279 * @see java.lang.System#getProperty(java.lang.String)
1280 * @see java.lang.System#getProperty(java.lang.String, java.lang.String)
1281 */
1282 public static Long getLong(String nm) {
1283 return getLong(nm, null);
1284 }
1285
1286 /**
1287 * Determines the {@code long} value of the system property
1288 * with the specified name.
1289 *
1290 * <p>The first argument is treated as the name of a system
1291 * property. System properties are accessible through the {@link
1292 * java.lang.System#getProperty(java.lang.String)} method. The
1293 * string value of this property is then interpreted as a {@code
1294 * long} value using the grammar supported by {@link Long#decode decode}
1295 * and a {@code Long} object representing this value is returned.
1296 *
1297 * <p>The second argument is the default value. A {@code Long} object
1298 * that represents the value of the second argument is returned if there
1299 * is no property of the specified name, if the property does not have
1300 * the correct numeric format, or if the specified name is empty or null.
1301 *
1302 * <p>In other words, this method returns a {@code Long} object equal
1303 * to the value of:
1304 *
1305 * <blockquote>
1306 * {@code getLong(nm, Long.valueOf(val))}
1307 * </blockquote>
1308 *
1309 * but in practice it may be implemented in a manner such as:
1310 *
1311 * <blockquote><pre>
1312 * Long result = getLong(nm, null);
1313 * return (result == null) ? Long.valueOf(val) : result;
1314 * </pre></blockquote>
1315 *
1316 * to avoid the unnecessary allocation of a {@code Long} object when
1317 * the default value is not needed.
1318 *
1319 * @param nm property name.
1320 * @param val default value.
1321 * @return the {@code Long} value of the property.
1322 * @throws SecurityException for the same reasons as
1323 * {@link System#getProperty(String) System.getProperty}
1324 * @see java.lang.System#getProperty(java.lang.String)
1325 * @see java.lang.System#getProperty(java.lang.String, java.lang.String)
1326 */
1327 public static Long getLong(String nm, long val) {
1328 Long result = Long.getLong(nm, null);
1329 return (result == null) ? Long.valueOf(val) : result;
1330 }
1331
1332 /**
1333 * Returns the {@code long} value of the system property with
1334 * the specified name. The first argument is treated as the name
1335 * of a system property. System properties are accessible through
1336 * the {@link java.lang.System#getProperty(java.lang.String)}
1337 * method. The string value of this property is then interpreted
1338 * as a {@code long} value, as per the
1339 * {@link Long#decode decode} method, and a {@code Long} object
1340 * representing this value is returned; in summary:
1341 *
1342 * <ul>
1343 * <li>If the property value begins with the two ASCII characters
1344 * {@code 0x} or the ASCII character {@code #}, not followed by
1345 * a minus sign, then the rest of it is parsed as a hexadecimal integer
1346 * exactly as for the method {@link #valueOf(java.lang.String, int)}
1347 * with radix 16.
1348 * <li>If the property value begins with the ASCII character
1349 * {@code 0} followed by another character, it is parsed as
1350 * an octal integer exactly as by the method {@link
1351 * #valueOf(java.lang.String, int)} with radix 8.
1352 * <li>Otherwise the property value is parsed as a decimal
1353 * integer exactly as by the method
1354 * {@link #valueOf(java.lang.String, int)} with radix 10.
1355 * </ul>
1356 *
1357 * <p>Note that, in every case, neither {@code L}
1358 * ({@code '\u005Cu004C'}) nor {@code l}
1359 * ({@code '\u005Cu006C'}) is permitted to appear at the end
1360 * of the property value as a type indicator, as would be
1361 * permitted in Java programming language source code.
1362 *
1363 * <p>The second argument is the default value. The default value is
1364 * returned if there is no property of the specified name, if the
1365 * property does not have the correct numeric format, or if the
1366 * specified name is empty or {@code null}.
1367 *
1368 * @param nm property name.
1369 * @param val default value.
1370 * @return the {@code Long} value of the property.
1371 * @throws SecurityException for the same reasons as
1372 * {@link System#getProperty(String) System.getProperty}
1373 * @see System#getProperty(java.lang.String)
1374 * @see System#getProperty(java.lang.String, java.lang.String)
1375 */
1376 public static Long getLong(String nm, Long val) {
1377 String v = null;
1378 try {
1379 v = System.getProperty(nm);
1380 } catch (IllegalArgumentException | NullPointerException e) {
1381 }
1382 if (v != null) {
1383 try {
1384 return Long.decode(v);
1385 } catch (NumberFormatException e) {
1386 }
1387 }
1388 return val;
1389 }
1390
1391 /**
1392 * Compares two {@code Long} objects numerically.
1393 *
1394 * @param anotherLong the {@code Long} to be compared.
1395 * @return the value {@code 0} if this {@code Long} is
1396 * equal to the argument {@code Long}; a value less than
1397 * {@code 0} if this {@code Long} is numerically less
1398 * than the argument {@code Long}; and a value greater
1399 * than {@code 0} if this {@code Long} is numerically
1400 * greater than the argument {@code Long} (signed
1401 * comparison).
1402 * @since 1.2
1403 */
1404 public int compareTo(Long anotherLong) {
1405 return compare(this.value, anotherLong.value);
1406 }
1407
1408 /**
1409 * Compares two {@code long} values numerically.
1410 * The value returned is identical to what would be returned by:
1411 * <pre>
1412 * Long.valueOf(x).compareTo(Long.valueOf(y))
1413 * </pre>
1414 *
1415 * @param x the first {@code long} to compare
1416 * @param y the second {@code long} to compare
1417 * @return the value {@code 0} if {@code x == y};
1418 * a value less than {@code 0} if {@code x < y}; and
1419 * a value greater than {@code 0} if {@code x > y}
1420 * @since 1.7
1421 */
1422 public static int compare(long x, long y) {
1423 return (x < y) ? -1 : ((x == y) ? 0 : 1);
1424 }
1425
1426 /**
1427 * Compares two {@code long} values numerically treating the values
1428 * as unsigned.
1429 *
1430 * @param x the first {@code long} to compare
1431 * @param y the second {@code long} to compare
1432 * @return the value {@code 0} if {@code x == y}; a value less
1433 * than {@code 0} if {@code x < y} as unsigned values; and
1434 * a value greater than {@code 0} if {@code x > y} as
1435 * unsigned values
1436 * @since 1.8
1437 */
1438 @IntrinsicCandidate
1439 public static int compareUnsigned(long x, long y) {
1440 return compare(x + MIN_VALUE, y + MIN_VALUE);
1441 }
1442
1443
1444 /**
1445 * Returns the unsigned quotient of dividing the first argument by
1446 * the second where each argument and the result is interpreted as
1447 * an unsigned value.
1448 *
1449 * <p>Note that in two's complement arithmetic, the three other
1450 * basic arithmetic operations of add, subtract, and multiply are
1451 * bit-wise identical if the two operands are regarded as both
1452 * being signed or both being unsigned. Therefore separate {@code
1453 * addUnsigned}, etc. methods are not provided.
1454 *
1455 * @param dividend the value to be divided
1456 * @param divisor the value doing the dividing
1457 * @return the unsigned quotient of the first argument divided by
1458 * the second argument
1459 * @see #remainderUnsigned
1460 * @since 1.8
1461 */
1462 @IntrinsicCandidate
1463 public static long divideUnsigned(long dividend, long divisor) {
1464 /* See Hacker's Delight (2nd ed), section 9.3 */
1465 if (divisor >= 0) {
1466 final long q = (dividend >>> 1) / divisor << 1;
1467 final long r = dividend - q * divisor;
1468 return q + ((r | ~(r - divisor)) >>> (Long.SIZE - 1));
1469 }
1470 return (dividend & ~(dividend - divisor)) >>> (Long.SIZE - 1);
1471 }
1472
1473 /**
1474 * Returns the unsigned remainder from dividing the first argument
1475 * by the second where each argument and the result is interpreted
1476 * as an unsigned value.
1477 *
1478 * @param dividend the value to be divided
1479 * @param divisor the value doing the dividing
1480 * @return the unsigned remainder of the first argument divided by
1481 * the second argument
1482 * @see #divideUnsigned
1483 * @since 1.8
1484 */
1485 @IntrinsicCandidate
1486 public static long remainderUnsigned(long dividend, long divisor) {
1487 /* See Hacker's Delight (2nd ed), section 9.3 */
1488 if (divisor >= 0) {
1489 final long q = (dividend >>> 1) / divisor << 1;
1490 final long r = dividend - q * divisor;
1491 /*
1492 * Here, 0 <= r < 2 * divisor
1493 * (1) When 0 <= r < divisor, the remainder is simply r.
1494 * (2) Otherwise the remainder is r - divisor.
1495 *
1496 * In case (1), r - divisor < 0. Applying ~ produces a long with
1497 * sign bit 0, so >> produces 0. The returned value is thus r.
1498 *
1499 * In case (2), a similar reasoning shows that >> produces -1,
1500 * so the returned value is r - divisor.
1501 */
1502 return r - ((~(r - divisor) >> (Long.SIZE - 1)) & divisor);
1503 }
1504 /*
1505 * (1) When dividend >= 0, the remainder is dividend.
1506 * (2) Otherwise
1507 * (2.1) When dividend < divisor, the remainder is dividend.
1508 * (2.2) Otherwise the remainder is dividend - divisor
1509 *
1510 * A reasoning similar to the above shows that the returned value
1511 * is as expected.
1512 */
1513 return dividend - (((dividend & ~(dividend - divisor)) >> (Long.SIZE - 1)) & divisor);
1514 }
1515
1516 // Bit Twiddling
1517
1518 /**
1519 * The number of bits used to represent a {@code long} value in two's
1520 * complement binary form.
1521 *
1522 * @since 1.5
1523 */
1524 @Native public static final int SIZE = 64;
1525
1526 /**
1527 * The number of bytes used to represent a {@code long} value in two's
1528 * complement binary form.
1529 *
1530 * @since 1.8
1531 */
1532 public static final int BYTES = SIZE / Byte.SIZE;
1533
1534 /**
1535 * Returns a {@code long} value with at most a single one-bit, in the
1536 * position of the highest-order ("leftmost") one-bit in the specified
1537 * {@code long} value. Returns zero if the specified value has no
1538 * one-bits in its two's complement binary representation, that is, if it
1539 * is equal to zero.
1540 *
1541 * @param i the value whose highest one bit is to be computed
1542 * @return a {@code long} value with a single one-bit, in the position
1543 * of the highest-order one-bit in the specified value, or zero if
1544 * the specified value is itself equal to zero.
1545 * @since 1.5
1546 */
1547 public static long highestOneBit(long i) {
1548 return i & (MIN_VALUE >>> numberOfLeadingZeros(i));
1549 }
1550
1551 /**
1552 * Returns a {@code long} value with at most a single one-bit, in the
1553 * position of the lowest-order ("rightmost") one-bit in the specified
1554 * {@code long} value. Returns zero if the specified value has no
1555 * one-bits in its two's complement binary representation, that is, if it
1556 * is equal to zero.
1557 *
1558 * @param i the value whose lowest one bit is to be computed
1559 * @return a {@code long} value with a single one-bit, in the position
1560 * of the lowest-order one-bit in the specified value, or zero if
1561 * the specified value is itself equal to zero.
1562 * @since 1.5
1563 */
1564 public static long lowestOneBit(long i) {
1565 // HD, Section 2-1
1566 return i & -i;
1567 }
1568
1569 /**
1570 * Returns the number of zero bits preceding the highest-order
1571 * ("leftmost") one-bit in the two's complement binary representation
1572 * of the specified {@code long} value. Returns 64 if the
1573 * specified value has no one-bits in its two's complement representation,
1574 * in other words if it is equal to zero.
1575 *
1576 * <p>Note that this method is closely related to the logarithm base 2.
1577 * For all positive {@code long} values x:
1578 * <ul>
1579 * <li>floor(log<sub>2</sub>(x)) = {@code 63 - numberOfLeadingZeros(x)}
1580 * <li>ceil(log<sub>2</sub>(x)) = {@code 64 - numberOfLeadingZeros(x - 1)}
1581 * </ul>
1582 *
1583 * @param i the value whose number of leading zeros is to be computed
1584 * @return 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, or 64 if the value
1587 * is equal to zero.
1588 * @since 1.5
1589 */
1590 @IntrinsicCandidate
1591 public static int numberOfLeadingZeros(long i) {
1592 int x = (int)(i >>> 32);
1593 return x == 0 ? 32 + Integer.numberOfLeadingZeros((int)i)
1594 : Integer.numberOfLeadingZeros(x);
1595 }
1596
1597 /**
1598 * Returns the number of zero bits following the lowest-order ("rightmost")
1599 * one-bit in the two's complement binary representation of the specified
1600 * {@code long} value. Returns 64 if the specified value has no
1601 * one-bits in its two's complement representation, in other words if it is
1602 * equal to zero.
1603 *
1604 * @param i the value whose number of trailing zeros is to be computed
1605 * @return the number of zero bits following the lowest-order ("rightmost")
1606 * one-bit in the two's complement binary representation of the
1607 * specified {@code long} value, or 64 if the value is equal
1608 * to zero.
1609 * @since 1.5
1610 */
1611 @IntrinsicCandidate
1612 public static int numberOfTrailingZeros(long i) {
1613 int x = (int)i;
1614 return x == 0 ? 32 + Integer.numberOfTrailingZeros((int)(i >>> 32))
1615 : Integer.numberOfTrailingZeros(x);
1616 }
1617
1618 /**
1619 * Returns the number of one-bits in the two's complement binary
1620 * representation of the specified {@code long} value. This function is
1621 * sometimes referred to as the <i>population count</i>.
1622 *
1623 * @param i the value whose bits are to be counted
1624 * @return the number of one-bits in the two's complement binary
1625 * representation of the specified {@code long} value.
1626 * @since 1.5
1627 */
1628 @IntrinsicCandidate
1629 public static int bitCount(long i) {
1630 // HD, Figure 5-2
1631 i = i - ((i >>> 1) & 0x5555555555555555L);
1632 i = (i & 0x3333333333333333L) + ((i >>> 2) & 0x3333333333333333L);
1633 i = (i + (i >>> 4)) & 0x0f0f0f0f0f0f0f0fL;
1634 i = i + (i >>> 8);
1635 i = i + (i >>> 16);
1636 i = i + (i >>> 32);
1637 return (int)i & 0x7f;
1638 }
1639
1640 /**
1641 * Returns the value obtained by rotating the two's complement binary
1642 * representation of the specified {@code long} value left by the
1643 * specified number of bits. (Bits shifted out of the left hand, or
1644 * high-order, side reenter on the right, or low-order.)
1645 *
1646 * <p>Note that left rotation with a negative distance is equivalent to
1647 * right rotation: {@code rotateLeft(val, -distance) == rotateRight(val,
1648 * distance)}. Note also that rotation by any multiple of 64 is a
1649 * no-op, so all but the last six bits of the rotation distance can be
1650 * ignored, even if the distance is negative: {@code rotateLeft(val,
1651 * distance) == rotateLeft(val, distance & 0x3F)}.
1652 *
1653 * @param i the value whose bits are to be rotated left
1654 * @param distance the number of bit positions to rotate left
1655 * @return 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.
1658 * @since 1.5
1659 */
1660 public static long rotateLeft(long i, int distance) {
1661 return (i << distance) | (i >>> -distance);
1662 }
1663
1664 /**
1665 * Returns the value obtained by rotating the two's complement binary
1666 * representation of the specified {@code long} value right by the
1667 * specified number of bits. (Bits shifted out of the right hand, or
1668 * low-order, side reenter on the left, or high-order.)
1669 *
1670 * <p>Note that right rotation with a negative distance is equivalent to
1671 * left rotation: {@code rotateRight(val, -distance) == rotateLeft(val,
1672 * distance)}. Note also that rotation by any multiple of 64 is a
1673 * no-op, so all but the last six bits of the rotation distance can be
1674 * ignored, even if the distance is negative: {@code rotateRight(val,
1675 * distance) == rotateRight(val, distance & 0x3F)}.
1676 *
1677 * @param i the value whose bits are to be rotated right
1678 * @param distance the number of bit positions to rotate right
1679 * @return 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.
1682 * @since 1.5
1683 */
1684 public static long rotateRight(long i, int distance) {
1685 return (i >>> distance) | (i << -distance);
1686 }
1687
1688 /**
1689 * Returns the value obtained by reversing the order of the bits in the
1690 * two's complement binary representation of the specified {@code long}
1691 * value.
1692 *
1693 * @param i the value to be reversed
1694 * @return the value obtained by reversing order of the bits in the
1695 * specified {@code long} value.
1696 * @since 1.5
1697 */
1698 @IntrinsicCandidate
1699 public static long reverse(long i) {
1700 // HD, Figure 7-1
1701 i = (i & 0x5555555555555555L) << 1 | (i >>> 1) & 0x5555555555555555L;
1702 i = (i & 0x3333333333333333L) << 2 | (i >>> 2) & 0x3333333333333333L;
1703 i = (i & 0x0f0f0f0f0f0f0f0fL) << 4 | (i >>> 4) & 0x0f0f0f0f0f0f0f0fL;
1704
1705 return reverseBytes(i);
1706 }
1707
1708 /**
1709 * Returns the value obtained by compressing the bits of the
1710 * specified {@code long} value, {@code i}, in accordance with
1711 * the specified bit mask.
1712 * <p>
1713 * For each one-bit value {@code mb} of the mask, from least
1714 * significant to most significant, the bit value of {@code i} at
1715 * the same bit location as {@code mb} is assigned to the compressed
1716 * value contiguously starting from the least significant bit location.
1717 * All the upper remaining bits of the compressed value are set
1718 * to zero.
1719 *
1720 * @apiNote
1721 * Consider the simple case of compressing the digits of a hexadecimal
1722 * value:
1723 * {@snippet lang="java" :
1724 * // Compressing drink to food
1725 * compress(0xCAFEBABEL, 0xFF00FFF0L) == 0xCABABL
1726 * }
1727 * Starting from the least significant hexadecimal digit at position 0
1728 * from the right, the mask {@code 0xFF00FFF0} selects hexadecimal digits
1729 * at positions 1, 2, 3, 6 and 7 of {@code 0xCAFEBABE}. The selected digits
1730 * occur in the resulting compressed value contiguously from digit position
1731 * 0 in the same order.
1732 * <p>
1733 * The following identities all return {@code true} and are helpful to
1734 * understand the behaviour of {@code compress}:
1735 * {@snippet lang="java" :
1736 * // Returns 1 if the bit at position n is one
1737 * compress(x, 1L << n) == (x >> n & 1)
1738 *
1739 * // Logical shift right
1740 * compress(x, -1L << n) == x >>> n
1741 *
1742 * // Any bits not covered by the mask are ignored
1743 * compress(x, m) == compress(x & m, m)
1744 *
1745 * // Compressing a value by itself
1746 * compress(m, m) == (m == -1 || m == 0) ? m : (1L << bitCount(m)) - 1
1747 *
1748 * // Expanding then compressing with the same mask
1749 * compress(expand(x, m), m) == x & compress(m, m)
1750 * }
1751 * <p>
1752 * The Sheep And Goats (SAG) operation (see Hacker's Delight, section 7.7)
1753 * can be implemented as follows:
1754 * {@snippet lang="java" :
1755 * long compressLeft(long i, long mask) {
1756 * // This implementation follows the description in Hacker's Delight which
1757 * // is informative. A more optimal implementation is:
1758 * // Long.compress(i, mask) << -Long.bitCount(mask)
1759 * return Long.reverse(
1760 * Long.compress(Long.reverse(i), Long.reverse(mask)));
1761 * }
1762 *
1763 * long sag(long i, long mask) {
1764 * return compressLeft(i, mask) | Long.compress(i, ~mask);
1765 * }
1766 *
1767 * // Separate the sheep from the goats
1768 * sag(0x00000000_CAFEBABEL, 0xFFFFFFFF_FF00FFF0L) == 0x00000000_CABABFEEL
1769 * }
1770 *
1771 * @param i the value whose bits are to be compressed
1772 * @param mask the bit mask
1773 * @return the compressed value
1774 * @see #expand
1775 * @since 19
1776 */
1777 @IntrinsicCandidate
1778 public static long compress(long i, long mask) {
1779 // See Hacker's Delight (2nd ed) section 7.4 Compress, or Generalized Extract
1780
1781 i = i & mask; // Clear irrelevant bits
1782 long maskCount = ~mask << 1; // Count 0's to right
1783
1784 for (int j = 0; j < 6; j++) {
1785 // Parallel prefix
1786 // Mask prefix identifies bits of the mask that have an odd number of 0's to the right
1787 long maskPrefix = parallelSuffix(maskCount);
1788 // Bits to move
1789 long maskMove = maskPrefix & mask;
1790 // Compress mask
1791 mask = (mask ^ maskMove) | (maskMove >>> (1 << j));
1792 // Bits of i to be moved
1793 long t = i & maskMove;
1794 // Compress i
1795 i = (i ^ t) | (t >>> (1 << j));
1796 // Adjust the mask count by identifying bits that have 0 to the right
1797 maskCount = maskCount & ~maskPrefix;
1798 }
1799 return i;
1800 }
1801
1802 /**
1803 * Returns the value obtained by expanding the bits of the
1804 * specified {@code long} value, {@code i}, in accordance with
1805 * the specified bit mask.
1806 * <p>
1807 * For each one-bit value {@code mb} of the mask, from least
1808 * significant to most significant, the next contiguous bit value
1809 * of {@code i} starting at the least significant bit is assigned
1810 * to the expanded value at the same bit location as {@code mb}.
1811 * All other remaining bits of the expanded value are set to zero.
1812 *
1813 * @apiNote
1814 * Consider the simple case of expanding the digits of a hexadecimal
1815 * value:
1816 * {@snippet lang="java" :
1817 * expand(0x0000CABABL, 0xFF00FFF0L) == 0xCA00BAB0L
1818 * }
1819 * Starting from the least significant hexadecimal digit at position 0
1820 * from the right, the mask {@code 0xFF00FFF0} selects the first five
1821 * hexadecimal digits of {@code 0x0000CABAB}. The selected digits occur
1822 * in the resulting expanded value in order at positions 1, 2, 3, 6, and 7.
1823 * <p>
1824 * The following identities all return {@code true} and are helpful to
1825 * understand the behaviour of {@code expand}:
1826 * {@snippet lang="java" :
1827 * // Logically shift right the bit at position 0
1828 * expand(x, 1L << n) == (x & 1) << n
1829 *
1830 * // Logically shift right
1831 * expand(x, -1L << n) == x << n
1832 *
1833 * // Expanding all bits returns the mask
1834 * expand(-1L, m) == m
1835 *
1836 * // Any bits not covered by the mask are ignored
1837 * expand(x, m) == expand(x, m) & m
1838 *
1839 * // Compressing then expanding with the same mask
1840 * expand(compress(x, m), m) == x & m
1841 * }
1842 * <p>
1843 * The select operation for determining the position of the one-bit with
1844 * index {@code n} in a {@code long} value can be implemented as follows:
1845 * {@snippet lang="java" :
1846 * long select(long i, long n) {
1847 * // the one-bit in i (the mask) with index n
1848 * long nthBit = Long.expand(1L << n, i);
1849 * // the bit position of the one-bit with index n
1850 * return Long.numberOfTrailingZeros(nthBit);
1851 * }
1852 *
1853 * // The one-bit with index 0 is at bit position 1
1854 * select(0b10101010_10101010, 0) == 1
1855 * // The one-bit with index 3 is at bit position 7
1856 * select(0b10101010_10101010, 3) == 7
1857 * }
1858 *
1859 * @param i the value whose bits are to be expanded
1860 * @param mask the bit mask
1861 * @return the expanded value
1862 * @see #compress
1863 * @since 19
1864 */
1865 @IntrinsicCandidate
1866 public static long expand(long i, long mask) {
1867 // Save original mask
1868 long originalMask = mask;
1869 // Count 0's to right
1870 long maskCount = ~mask << 1;
1871 long maskPrefix = parallelSuffix(maskCount);
1872 // Bits to move
1873 long maskMove1 = maskPrefix & mask;
1874 // Compress mask
1875 mask = (mask ^ maskMove1) | (maskMove1 >>> (1 << 0));
1876 maskCount = maskCount & ~maskPrefix;
1877
1878 maskPrefix = parallelSuffix(maskCount);
1879 // Bits to move
1880 long maskMove2 = maskPrefix & mask;
1881 // Compress mask
1882 mask = (mask ^ maskMove2) | (maskMove2 >>> (1 << 1));
1883 maskCount = maskCount & ~maskPrefix;
1884
1885 maskPrefix = parallelSuffix(maskCount);
1886 // Bits to move
1887 long maskMove3 = maskPrefix & mask;
1888 // Compress mask
1889 mask = (mask ^ maskMove3) | (maskMove3 >>> (1 << 2));
1890 maskCount = maskCount & ~maskPrefix;
1891
1892 maskPrefix = parallelSuffix(maskCount);
1893 // Bits to move
1894 long maskMove4 = maskPrefix & mask;
1895 // Compress mask
1896 mask = (mask ^ maskMove4) | (maskMove4 >>> (1 << 3));
1897 maskCount = maskCount & ~maskPrefix;
1898
1899 maskPrefix = parallelSuffix(maskCount);
1900 // Bits to move
1901 long maskMove5 = maskPrefix & mask;
1902 // Compress mask
1903 mask = (mask ^ maskMove5) | (maskMove5 >>> (1 << 4));
1904 maskCount = maskCount & ~maskPrefix;
1905
1906 maskPrefix = parallelSuffix(maskCount);
1907 // Bits to move
1908 long maskMove6 = maskPrefix & mask;
1909
1910 long t = i << (1 << 5);
1911 i = (i & ~maskMove6) | (t & maskMove6);
1912 t = i << (1 << 4);
1913 i = (i & ~maskMove5) | (t & maskMove5);
1914 t = i << (1 << 3);
1915 i = (i & ~maskMove4) | (t & maskMove4);
1916 t = i << (1 << 2);
1917 i = (i & ~maskMove3) | (t & maskMove3);
1918 t = i << (1 << 1);
1919 i = (i & ~maskMove2) | (t & maskMove2);
1920 t = i << (1 << 0);
1921 i = (i & ~maskMove1) | (t & maskMove1);
1922
1923 // Clear irrelevant bits
1924 return i & originalMask;
1925 }
1926
1927 @ForceInline
1928 private static long parallelSuffix(long maskCount) {
1929 long maskPrefix = maskCount ^ (maskCount << 1);
1930 maskPrefix = maskPrefix ^ (maskPrefix << 2);
1931 maskPrefix = maskPrefix ^ (maskPrefix << 4);
1932 maskPrefix = maskPrefix ^ (maskPrefix << 8);
1933 maskPrefix = maskPrefix ^ (maskPrefix << 16);
1934 maskPrefix = maskPrefix ^ (maskPrefix << 32);
1935 return maskPrefix;
1936 }
1937
1938 /**
1939 * Returns the signum function of the specified {@code long} value. (The
1940 * return value is -1 if the specified value is negative; 0 if the
1941 * specified value is zero; and 1 if the specified value is positive.)
1942 *
1943 * @param i the value whose signum is to be computed
1944 * @return the signum function of the specified {@code long} value.
1945 * @since 1.5
1946 */
1947 public static int signum(long i) {
1948 // HD, Section 2-7
1949 return (int) ((i >> 63) | (-i >>> 63));
1950 }
1951
1952 /**
1953 * Returns the value obtained by reversing the order of the bytes in the
1954 * two's complement representation of the specified {@code long} value.
1955 *
1956 * @param i the value whose bytes are to be reversed
1957 * @return the value obtained by reversing the bytes in the specified
1958 * {@code long} value.
1959 * @since 1.5
1960 */
1961 @IntrinsicCandidate
1962 public static long reverseBytes(long i) {
1963 i = (i & 0x00ff00ff00ff00ffL) << 8 | (i >>> 8) & 0x00ff00ff00ff00ffL;
1964 return (i << 48) | ((i & 0xffff0000L) << 16) |
1965 ((i >>> 16) & 0xffff0000L) | (i >>> 48);
1966 }
1967
1968 /**
1969 * Adds two {@code long} values together as per the + operator.
1970 *
1971 * @param a the first operand
1972 * @param b the second operand
1973 * @return the sum of {@code a} and {@code b}
1974 * @see java.util.function.BinaryOperator
1975 * @since 1.8
1976 */
1977 public static long sum(long a, long b) {
1978 return a + b;
1979 }
1980
1981 /**
1982 * Returns the greater of two {@code long} values
1983 * as if by calling {@link Math#max(long, long) Math.max}.
1984 *
1985 * @param a the first operand
1986 * @param b the second operand
1987 * @return the greater of {@code a} and {@code b}
1988 * @see java.util.function.BinaryOperator
1989 * @since 1.8
1990 */
1991 public static long max(long a, long b) {
1992 return Math.max(a, b);
1993 }
1994
1995 /**
1996 * Returns the smaller of two {@code long} values
1997 * as if by calling {@link Math#min(long, long) Math.min}.
1998 *
1999 * @param a the first operand
2000 * @param b the second operand
2001 * @return the smaller of {@code a} and {@code b}
2002 * @see java.util.function.BinaryOperator
2003 * @since 1.8
2004 */
2005 public static long min(long a, long b) {
2006 return Math.min(a, b);
2007 }
2008
2009 /**
2010 * Returns an {@link Optional} containing the nominal descriptor for this
2011 * instance, which is the instance itself.
2012 *
2013 * @return an {@link Optional} describing the {@linkplain Long} instance
2014 * @since 12
2015 */
2016 @Override
2017 public Optional<Long> describeConstable() {
2018 return Optional.of(this);
2019 }
2020
2021 /**
2022 * Resolves this instance as a {@link ConstantDesc}, the result of which is
2023 * the instance itself.
2024 *
2025 * @param lookup ignored
2026 * @return the {@linkplain Long} instance
2027 * @since 12
2028 */
2029 @Override
2030 public Long resolveConstantDesc(MethodHandles.Lookup lookup) {
2031 return this;
2032 }
2033
2034 /** use serialVersionUID from JDK 1.0.2 for interoperability */
2035 @java.io.Serial
2036 @Native private static final long serialVersionUID = 4290774380558885855L;
2037 }