1 /*
2 * Copyright (c) 1994, 2024, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 package java.lang;
27
28 import java.lang.annotation.Native;
29 import java.lang.invoke.MethodHandles;
30 import java.lang.constant.Constable;
31 import java.lang.constant.ConstantDesc;
32 import java.math.*;
33 import java.util.Objects;
34 import java.util.Optional;
35
36 import jdk.internal.misc.CDS;
37 import jdk.internal.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 is the {@linkplain
49 * java.lang##wrapperClass wrapper class} for values of the primitive
50 * type {@code long}. 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 <cite>Hacker's
68 * Delight</cite>, (Addison Wesley, 2002) and <cite>Hacker's
69 * Delight, Second Edition</cite>, (Pearson Education, 2013).
70 *
71 * @author Lee Boynton
72 * @author Arthur van Hoff
73 * @author Josh Bloch
74 * @author Joseph D. Darcy
75 * @since 1.0
76 */
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 public static final Class<Long> TYPE = Class.getPrimitiveClass("long");
99
100 /**
101 * Returns a string representation of the first argument in the
102 * radix specified by the second argument.
103 *
104 * <p>If the radix is smaller than {@code Character.MIN_RADIX}
105 * or larger than {@code Character.MAX_RADIX}, then the radix
106 * {@code 10} is used instead.
107 *
108 * <p>If the first argument is negative, the first element of the
109 * result is the ASCII minus sign {@code '-'}
110 * ({@code '\u005Cu002d'}). If the first argument is not
111 * negative, no sign character appears in the result.
112 *
113 * <p>The remaining characters of the result represent the magnitude
114 * of the first argument. If the magnitude is zero, it is
115 * represented by a single zero character {@code '0'}
116 * ({@code '\u005Cu0030'}); otherwise, the first character of
117 * the representation of the magnitude will not be the zero
118 * character. The following ASCII characters are used as digits:
119 *
120 * <blockquote>
121 * {@code 0123456789abcdefghijklmnopqrstuvwxyz}
122 * </blockquote>
123 *
124 * These are {@code '\u005Cu0030'} through
125 * {@code '\u005Cu0039'} and {@code '\u005Cu0061'} through
126 * {@code '\u005Cu007a'}. If {@code radix} is
127 * <var>N</var>, then the first <var>N</var> of these characters
128 * are used as radix-<var>N</var> digits in the order shown. Thus,
129 * the digits for hexadecimal (radix 16) are
130 * {@code 0123456789abcdef}. If uppercase letters are
131 * desired, the {@link java.lang.String#toUpperCase()} method may
132 * be called on the result:
133 *
134 * <blockquote>
135 * {@code Long.toString(n, 16).toUpperCase()}
136 * </blockquote>
137 *
138 * @param i a {@code long} to be converted to a string.
139 * @param radix the radix to use in the string representation.
140 * @return a string representation of the argument in the specified radix.
141 * @see java.lang.Character#MAX_RADIX
142 * @see java.lang.Character#MIN_RADIX
143 */
144 public static String toString(long i, int radix) {
145 if (radix < Character.MIN_RADIX || radix > Character.MAX_RADIX)
146 radix = 10;
147 if (radix == 10)
148 return toString(i);
149
150 if (COMPACT_STRINGS) {
151 byte[] buf = new byte[65];
152 int charPos = 64;
153 boolean negative = (i < 0);
154
155 if (!negative) {
156 i = -i;
157 }
158
159 while (i <= -radix) {
160 buf[charPos--] = (byte)Integer.digits[(int)(-(i % radix))];
161 i = i / radix;
162 }
163 buf[charPos] = (byte)Integer.digits[(int)(-i)];
164
165 if (negative) {
166 buf[--charPos] = '-';
167 }
168 return StringLatin1.newString(buf, charPos, (65 - charPos));
169 }
170 return toStringUTF16(i, radix);
171 }
172
173 private static String toStringUTF16(long i, int radix) {
174 byte[] buf = new byte[65 * 2];
175 int charPos = 64;
176 boolean negative = (i < 0);
177 if (!negative) {
178 i = -i;
179 }
180 while (i <= -radix) {
181 StringUTF16.putChar(buf, charPos--, Integer.digits[(int)(-(i % radix))]);
182 i = i / radix;
183 }
184 StringUTF16.putChar(buf, charPos, Integer.digits[(int)(-i)]);
185 if (negative) {
186 StringUTF16.putChar(buf, --charPos, '-');
187 }
188 return StringUTF16.newString(buf, charPos, (65 - charPos));
189 }
190
191 /**
192 * Returns a string representation of the first argument as an
193 * unsigned integer value in the radix specified by the second
194 * argument.
195 *
196 * <p>If the radix is smaller than {@code Character.MIN_RADIX}
197 * or larger than {@code Character.MAX_RADIX}, then the radix
198 * {@code 10} is used instead.
199 *
200 * <p>Note that since the first argument is treated as an unsigned
201 * value, no leading sign character is printed.
202 *
203 * <p>If the magnitude is zero, it is represented by a single zero
204 * character {@code '0'} ({@code '\u005Cu0030'}); otherwise,
205 * the first character of the representation of the magnitude will
206 * not be the zero character.
207 *
208 * <p>The behavior of radixes and the characters used as digits
209 * are the same as {@link #toString(long, int) toString}.
210 *
211 * @param i an integer to be converted to an unsigned string.
212 * @param radix the radix to use in the string representation.
213 * @return an unsigned string representation of the argument in the specified radix.
214 * @see #toString(long, int)
215 * @since 1.8
216 */
217 public static String toUnsignedString(long i, int radix) {
218 if (i >= 0)
219 return toString(i, radix);
220 else {
221 return switch (radix) {
222 case 2 -> toBinaryString(i);
223 case 4 -> toUnsignedString0(i, 2);
224 case 8 -> toOctalString(i);
225 case 10 -> {
226 /*
227 * We can get the effect of an unsigned division by 10
228 * on a long value by first shifting right, yielding a
229 * positive value, and then dividing by 5. This
230 * allows the last digit and preceding digits to be
231 * isolated more quickly than by an initial conversion
232 * to BigInteger.
233 */
234 long quot = (i >>> 1) / 5;
235 long rem = i - quot * 10;
236 yield toString(quot) + rem;
237 }
238 case 16 -> toHexString(i);
239 case 32 -> toUnsignedString0(i, 5);
240 default -> toUnsignedBigInteger(i).toString(radix);
241 };
242 }
243 }
244
245 /**
246 * Return a BigInteger equal to the unsigned value of the
247 * argument.
248 */
249 private static BigInteger toUnsignedBigInteger(long i) {
250 if (i >= 0L)
251 return BigInteger.valueOf(i);
252 else {
253 int upper = (int) (i >>> 32);
254 int lower = (int) i;
255
256 // return (upper << 32) + lower
257 return (BigInteger.valueOf(Integer.toUnsignedLong(upper))).shiftLeft(32).
258 add(BigInteger.valueOf(Integer.toUnsignedLong(lower)));
259 }
260 }
261
262 /**
263 * Returns a string representation of the {@code long}
264 * argument as an unsigned integer in base 16.
265 *
266 * <p>The unsigned {@code long} value is the argument plus
267 * 2<sup>64</sup> if the argument is negative; otherwise, it is
268 * equal to the argument. This value is converted to a string of
269 * ASCII digits in hexadecimal (base 16) with no extra
270 * leading {@code 0}s.
271 *
272 * <p>The value of the argument can be recovered from the returned
273 * string {@code s} by calling {@link
274 * Long#parseUnsignedLong(String, int) Long.parseUnsignedLong(s,
275 * 16)}.
276 *
277 * <p>If the unsigned magnitude is zero, it is represented by a
278 * single zero character {@code '0'} ({@code '\u005Cu0030'});
279 * otherwise, the first character of the representation of the
280 * unsigned magnitude will not be the zero character. The
281 * following characters are used as hexadecimal digits:
282 *
283 * <blockquote>
284 * {@code 0123456789abcdef}
285 * </blockquote>
286 *
287 * These are the characters {@code '\u005Cu0030'} through
288 * {@code '\u005Cu0039'} and {@code '\u005Cu0061'} through
289 * {@code '\u005Cu0066'}. If uppercase letters are desired,
290 * the {@link java.lang.String#toUpperCase()} method may be called
291 * on the result:
292 *
293 * <blockquote>
294 * {@code Long.toHexString(n).toUpperCase()}
295 * </blockquote>
296 *
297 * @apiNote
298 * The {@link java.util.HexFormat} class provides formatting and parsing
299 * of byte arrays and primitives to return a string or adding to an {@link Appendable}.
300 * {@code HexFormat} formats and parses uppercase or lowercase hexadecimal characters,
301 * with leading zeros and for byte arrays includes for each byte
302 * a delimiter, prefix, and suffix.
303 *
304 * @param i a {@code long} to be converted to a string.
305 * @return the string representation of the unsigned {@code long}
306 * value represented by the argument in hexadecimal
307 * (base 16).
308 * @see java.util.HexFormat
309 * @see #parseUnsignedLong(String, int)
310 * @see #toUnsignedString(long, int)
311 * @since 1.0.2
312 */
313 public static String toHexString(long i) {
314 return toUnsignedString0(i, 4);
315 }
316
317 /**
318 * Returns a string representation of the {@code long}
319 * argument as an unsigned integer in base 8.
320 *
321 * <p>The unsigned {@code long} value is the argument plus
322 * 2<sup>64</sup> if the argument is negative; otherwise, it is
323 * equal to the argument. This value is converted to a string of
324 * ASCII digits in octal (base 8) with no extra leading
325 * {@code 0}s.
326 *
327 * <p>The value of the argument can be recovered from the returned
328 * string {@code s} by calling {@link
329 * Long#parseUnsignedLong(String, int) Long.parseUnsignedLong(s,
330 * 8)}.
331 *
332 * <p>If the unsigned magnitude is zero, it is represented by a
333 * single zero character {@code '0'} ({@code '\u005Cu0030'});
334 * otherwise, the first character of the representation of the
335 * unsigned magnitude will not be the zero character. The
336 * following characters are used as octal digits:
337 *
338 * <blockquote>
339 * {@code 01234567}
340 * </blockquote>
341 *
342 * These are the characters {@code '\u005Cu0030'} through
343 * {@code '\u005Cu0037'}.
344 *
345 * @param i a {@code long} to be converted to a string.
346 * @return the string representation of the unsigned {@code long}
347 * value represented by the argument in octal (base 8).
348 * @see #parseUnsignedLong(String, int)
349 * @see #toUnsignedString(long, int)
350 * @since 1.0.2
351 */
352 public static String toOctalString(long i) {
353 return toUnsignedString0(i, 3);
354 }
355
356 /**
357 * Returns a string representation of the {@code long}
358 * argument as an unsigned integer in base 2.
359 *
360 * <p>The unsigned {@code long} value is the argument plus
361 * 2<sup>64</sup> if the argument is negative; otherwise, it is
362 * equal to the argument. This value is converted to a string of
363 * ASCII digits in binary (base 2) with no extra leading
364 * {@code 0}s.
365 *
366 * <p>The value of the argument can be recovered from the returned
367 * string {@code s} by calling {@link
368 * Long#parseUnsignedLong(String, int) Long.parseUnsignedLong(s,
369 * 2)}.
370 *
371 * <p>If the unsigned magnitude is zero, it is represented by a
372 * single zero character {@code '0'} ({@code '\u005Cu0030'});
373 * otherwise, the first character of the representation of the
374 * unsigned magnitude will not be the zero character. The
375 * characters {@code '0'} ({@code '\u005Cu0030'}) and {@code
376 * '1'} ({@code '\u005Cu0031'}) are used as binary digits.
377 *
378 * @param i a {@code long} to be converted to a string.
379 * @return the string representation of the unsigned {@code long}
380 * value represented by the argument in binary (base 2).
381 * @see #parseUnsignedLong(String, int)
382 * @see #toUnsignedString(long, int)
383 * @since 1.0.2
384 */
385 public static String toBinaryString(long i) {
386 return toUnsignedString0(i, 1);
387 }
388
389 /**
390 * Format a long (treated as unsigned) into a String.
391 * @param val the value to format
392 * @param shift the log2 of the base to format in (4 for hex, 3 for octal, 1 for binary)
393 */
394 static String toUnsignedString0(long val, int shift) {
395 // assert shift > 0 && shift <=5 : "Illegal shift value";
396 int mag = Long.SIZE - Long.numberOfLeadingZeros(val);
397 int chars = Math.max(((mag + (shift - 1)) / shift), 1);
398 if (COMPACT_STRINGS) {
399 byte[] buf = new byte[chars];
400 formatUnsignedLong0(val, shift, buf, 0, chars);
401 return new String(buf, LATIN1);
402 } else {
403 byte[] buf = new byte[chars * 2];
404 formatUnsignedLong0UTF16(val, shift, buf, 0, chars);
405 return new String(buf, UTF16);
406 }
407 }
408
409 /**
410 * Format a long (treated as unsigned) into a byte buffer (LATIN1 version). If
411 * {@code len} exceeds the formatted ASCII representation of {@code val},
412 * {@code buf} will be padded with leading zeroes.
413 *
414 * @param val the unsigned long to format
415 * @param shift the log2 of the base to format in (4 for hex, 3 for octal, 1 for binary)
416 * @param buf the byte buffer to write to
417 * @param offset the offset in the destination buffer to start at
418 * @param len the number of characters to write
419 */
420 private static void formatUnsignedLong0(long val, int shift, byte[] buf, int offset, int len) {
421 int charPos = offset + len;
422 int radix = 1 << shift;
423 int mask = radix - 1;
424 do {
425 buf[--charPos] = (byte)Integer.digits[((int) val) & mask];
426 val >>>= shift;
427 } while (charPos > offset);
428 }
429
430 /**
431 * Format a long (treated as unsigned) into a byte buffer (UTF16 version). If
432 * {@code len} exceeds the formatted ASCII representation of {@code val},
433 * {@code buf} will be padded with leading zeroes.
434 *
435 * @param val the unsigned long to format
436 * @param shift the log2 of the base to format in (4 for hex, 3 for octal, 1 for binary)
437 * @param buf the byte buffer to write to
438 * @param offset the offset in the destination buffer to start at
439 * @param len the number of characters to write
440 */
441 private static void formatUnsignedLong0UTF16(long val, int shift, byte[] buf, int offset, int len) {
442 int charPos = offset + len;
443 int radix = 1 << shift;
444 int mask = radix - 1;
445 do {
446 StringUTF16.putChar(buf, --charPos, Integer.digits[((int) val) & mask]);
447 val >>>= shift;
448 } while (charPos > offset);
449 }
450
451 /**
452 * Returns a {@code String} object representing the specified
453 * {@code long}. The argument is converted to signed decimal
454 * representation and returned as a string, exactly as if the
455 * argument and the radix 10 were given as arguments to the {@link
456 * #toString(long, int)} method.
457 *
458 * @param i a {@code long} to be converted.
459 * @return a string representation of the argument in base 10.
460 */
461 public static String toString(long i) {
462 int size = DecimalDigits.stringSize(i);
463 if (COMPACT_STRINGS) {
464 byte[] buf = new byte[size];
465 StringLatin1.getChars(i, size, buf);
466 return new String(buf, LATIN1);
467 } else {
468 byte[] buf = new byte[size * 2];
469 StringUTF16.getChars(i, size, buf);
470 return new String(buf, UTF16);
471 }
472 }
473
474 /**
475 * Returns a string representation of the argument as an unsigned
476 * decimal value.
477 *
478 * The argument is converted to unsigned decimal representation
479 * and returned as a string exactly as if the argument and radix
480 * 10 were given as arguments to the {@link #toUnsignedString(long,
481 * int)} method.
482 *
483 * @param i an integer to be converted to an unsigned string.
484 * @return an unsigned string representation of the argument.
485 * @see #toUnsignedString(long, int)
486 * @since 1.8
487 */
488 public static String toUnsignedString(long i) {
489 return toUnsignedString(i, 10);
490 }
491
492 /**
493 * Parses the string argument as a signed {@code long} in the
494 * radix specified by the second argument. The characters in the
495 * string must all be digits of the specified radix (as determined
496 * by whether {@link java.lang.Character#digit(char, int)} returns
497 * a nonnegative value), except that the first character may be an
498 * ASCII minus sign {@code '-'} ({@code '\u005Cu002D'}) to
499 * indicate a negative value or an ASCII plus sign {@code '+'}
500 * ({@code '\u005Cu002B'}) to indicate a positive value. The
501 * resulting {@code long} value is returned.
502 *
503 * <p>Note that neither the character {@code L}
504 * ({@code '\u005Cu004C'}) nor {@code l}
505 * ({@code '\u005Cu006C'}) is permitted to appear at the end
506 * of the string as a type indicator, as would be permitted in
507 * Java programming language source code - except that either
508 * {@code L} or {@code l} may appear as a digit for a
509 * radix greater than or equal to 22.
510 *
511 * <p>An exception of type {@code NumberFormatException} is
512 * thrown if any of the following situations occurs:
513 * <ul>
514 *
515 * <li>The first argument is {@code null} or is a string of
516 * length zero.
517 *
518 * <li>The {@code radix} is either smaller than {@link
519 * java.lang.Character#MIN_RADIX} or larger than {@link
520 * java.lang.Character#MAX_RADIX}.
521 *
522 * <li>Any character of the string is not a digit of the specified
523 * radix, except that the first character may be a minus sign
524 * {@code '-'} ({@code '\u005Cu002d'}) or plus sign {@code
525 * '+'} ({@code '\u005Cu002B'}) provided that the string is
526 * longer than length 1.
527 *
528 * <li>The value represented by the string is not a value of type
529 * {@code long}.
530 * </ul>
531 *
532 * <p>Examples:
533 * <blockquote><pre>
534 * parseLong("0", 10) returns 0L
535 * parseLong("473", 10) returns 473L
536 * parseLong("+42", 10) returns 42L
537 * parseLong("-0", 10) returns 0L
538 * parseLong("-FF", 16) returns -255L
539 * parseLong("1100110", 2) returns 102L
540 * parseLong("99", 8) throws a NumberFormatException
541 * parseLong("Hazelnut", 10) throws a NumberFormatException
542 * parseLong("Hazelnut", 36) returns 1356099454469L
543 * </pre></blockquote>
544 *
545 * @param s the {@code String} containing the
546 * {@code long} representation to be parsed.
547 * @param radix the radix to be used while parsing {@code s}.
548 * @return the {@code long} represented by the string argument in
549 * the specified radix.
550 * @throws NumberFormatException if the string does not contain a
551 * parsable {@code long}.
552 */
553 public static long parseLong(String s, int radix)
554 throws NumberFormatException {
555 if (s == null) {
556 throw new NumberFormatException("Cannot parse null string");
557 }
558
559 if (radix < Character.MIN_RADIX) {
560 throw new NumberFormatException(String.format(
561 "radix %s less than Character.MIN_RADIX", radix));
562 }
563
564 if (radix > Character.MAX_RADIX) {
565 throw new NumberFormatException(String.format(
566 "radix %s greater than Character.MAX_RADIX", radix));
567 }
568
569 int len = s.length();
570 if (len == 0) {
571 throw NumberFormatException.forInputString("", radix);
572 }
573 int digit = ~0xFF;
574 int i = 0;
575 char firstChar = s.charAt(i++);
576 if (firstChar != '-' && firstChar != '+') {
577 digit = digit(firstChar, radix);
578 }
579 if (digit >= 0 || digit == ~0xFF && len > 1) {
580 long limit = firstChar != '-' ? MIN_VALUE + 1 : MIN_VALUE;
581 long multmin = limit / radix;
582 long result = -(digit & 0xFF);
583 boolean inRange = true;
584 /* Accumulating negatively avoids surprises near MAX_VALUE */
585 while (i < len && (digit = digit(s.charAt(i++), radix)) >= 0
586 && (inRange = result > multmin
587 || result == multmin && digit <= (int) (radix * multmin - limit))) {
588 result = radix * result - digit;
589 }
590 if (inRange && i == len && digit >= 0) {
591 return firstChar != '-' ? -result : result;
592 }
593 }
594 throw NumberFormatException.forInputString(s, radix);
595 }
596
597 /**
598 * Parses the {@link CharSequence} argument as a signed {@code long} in
599 * the specified {@code radix}, beginning at the specified
600 * {@code beginIndex} and extending to {@code endIndex - 1}.
601 *
602 * <p>The method does not take steps to guard against the
603 * {@code CharSequence} being mutated while parsing.
604 *
605 * @param s the {@code CharSequence} containing the {@code long}
606 * representation to be parsed
607 * @param beginIndex the beginning index, inclusive.
608 * @param endIndex the ending index, exclusive.
609 * @param radix the radix to be used while parsing {@code s}.
610 * @return the signed {@code long} represented by the subsequence in
611 * the specified radix.
612 * @throws NullPointerException if {@code s} is null.
613 * @throws IndexOutOfBoundsException if {@code beginIndex} is
614 * negative, or if {@code beginIndex} is greater than
615 * {@code endIndex} or if {@code endIndex} is greater than
616 * {@code s.length()}.
617 * @throws NumberFormatException if the {@code CharSequence} does not
618 * contain a parsable {@code long} in the specified
619 * {@code radix}, or if {@code radix} is either smaller than
620 * {@link java.lang.Character#MIN_RADIX} or larger than
621 * {@link java.lang.Character#MAX_RADIX}.
622 * @since 9
623 */
624 public static long parseLong(CharSequence s, int beginIndex, int endIndex, int radix)
625 throws NumberFormatException {
626 Objects.requireNonNull(s);
627 Objects.checkFromToIndex(beginIndex, endIndex, s.length());
628
629 if (radix < Character.MIN_RADIX) {
630 throw new NumberFormatException(String.format(
631 "radix %s less than Character.MIN_RADIX", radix));
632 }
633
634 if (radix > Character.MAX_RADIX) {
635 throw new NumberFormatException(String.format(
636 "radix %s greater than Character.MAX_RADIX", radix));
637 }
638
639 /*
640 * While s can be concurrently modified, it is ensured that each
641 * of its characters is read at most once, from lower to higher indices.
642 * This is obtained by reading them using the pattern s.charAt(i++),
643 * and by not updating i anywhere else.
644 */
645 if (beginIndex == endIndex) {
646 throw NumberFormatException.forInputString("", radix);
647 }
648 int digit = ~0xFF; // ~0xFF means firstChar char is sign
649 int i = beginIndex;
650 char firstChar = s.charAt(i++);
651 if (firstChar != '-' && firstChar != '+') {
652 digit = digit(firstChar, radix);
653 }
654 if (digit >= 0 || digit == ~0xFF && endIndex - beginIndex > 1) {
655 long limit = firstChar != '-' ? MIN_VALUE + 1 : MIN_VALUE;
656 long multmin = limit / radix;
657 long result = -(digit & 0xFF);
658 boolean inRange = true;
659 /* Accumulating negatively avoids surprises near MAX_VALUE */
660 while (i < endIndex && (digit = digit(s.charAt(i++), radix)) >= 0
661 && (inRange = result > multmin
662 || result == multmin && digit <= (int) (radix * multmin - limit))) {
663 result = radix * result - digit;
664 }
665 if (inRange && i == endIndex && digit >= 0) {
666 return firstChar != '-' ? -result : result;
667 }
668 }
669 throw NumberFormatException.forCharSequence(s, beginIndex,
670 endIndex, i - (digit < -1 ? 0 : 1));
671 }
672
673 /**
674 * Parses the string argument as a signed decimal {@code long}.
675 * The characters in the string must all be decimal digits, except
676 * that the first character may be an ASCII minus sign {@code '-'}
677 * ({@code \u005Cu002D'}) to indicate a negative value or an
678 * ASCII plus sign {@code '+'} ({@code '\u005Cu002B'}) to
679 * indicate a positive value. The resulting {@code long} value is
680 * returned, exactly as if the argument and the radix {@code 10}
681 * were given as arguments to the {@link
682 * #parseLong(java.lang.String, int)} method.
683 *
684 * <p>Note that neither the character {@code L}
685 * ({@code '\u005Cu004C'}) nor {@code l}
686 * ({@code '\u005Cu006C'}) is permitted to appear at the end
687 * of the string as a type indicator, as would be permitted in
688 * Java programming language source code.
689 *
690 * @param s a {@code String} containing the {@code long}
691 * representation to be parsed
692 * @return the {@code long} represented by the argument in
693 * decimal.
694 * @throws NumberFormatException if the string does not contain a
695 * parsable {@code long}.
696 */
697 public static long parseLong(String s) throws NumberFormatException {
698 return parseLong(s, 10);
699 }
700
701 /**
702 * Parses the string argument as an unsigned {@code long} in the
703 * radix specified by the second argument. An unsigned integer
704 * maps the values usually associated with negative numbers to
705 * positive numbers larger than {@code MAX_VALUE}.
706 *
707 * The characters in the string must all be digits of the
708 * specified radix (as determined by whether {@link
709 * java.lang.Character#digit(char, int)} returns a nonnegative
710 * value), except that the first character may be an ASCII plus
711 * sign {@code '+'} ({@code '\u005Cu002B'}). The resulting
712 * integer value is returned.
713 *
714 * <p>An exception of type {@code NumberFormatException} is
715 * thrown if any of the following situations occurs:
716 * <ul>
717 * <li>The first argument is {@code null} or is a string of
718 * length zero.
719 *
720 * <li>The radix is either smaller than
721 * {@link java.lang.Character#MIN_RADIX} or
722 * larger than {@link java.lang.Character#MAX_RADIX}.
723 *
724 * <li>Any character of the string is not a digit of the specified
725 * radix, except that the first character may be a plus sign
726 * {@code '+'} ({@code '\u005Cu002B'}) provided that the
727 * string is longer than length 1.
728 *
729 * <li>The value represented by the string is larger than the
730 * largest unsigned {@code long}, 2<sup>64</sup>-1.
731 *
732 * </ul>
733 *
734 *
735 * @param s the {@code String} containing the unsigned integer
736 * representation to be parsed
737 * @param radix the radix to be used while parsing {@code s}.
738 * @return the unsigned {@code long} represented by the string
739 * argument in the specified radix.
740 * @throws NumberFormatException if the {@code String}
741 * does not contain a parsable {@code long}.
742 * @since 1.8
743 */
744 public static long parseUnsignedLong(String s, int radix)
745 throws NumberFormatException {
746 if (s == null) {
747 throw new NumberFormatException("Cannot parse null string");
748 }
749
750 if (radix < Character.MIN_RADIX) {
751 throw new NumberFormatException(String.format(
752 "radix %s less than Character.MIN_RADIX", radix));
753 }
754
755 if (radix > Character.MAX_RADIX) {
756 throw new NumberFormatException(String.format(
757 "radix %s greater than Character.MAX_RADIX", radix));
758 }
759
760 int len = s.length();
761 if (len == 0) {
762 throw NumberFormatException.forInputString(s, radix);
763 }
764 int i = 0;
765 char firstChar = s.charAt(i++);
766 if (firstChar == '-') {
767 throw new NumberFormatException(String.format(
768 "Illegal leading minus sign on unsigned string %s.", s));
769 }
770 int digit = ~0xFF;
771 if (firstChar != '+') {
772 digit = digit(firstChar, radix);
773 }
774 if (digit >= 0 || digit == ~0xFF && len > 1) {
775 long multmax = divideUnsigned(-1L, radix); // -1L is max unsigned long
776 long result = digit & 0xFF;
777 boolean inRange = true;
778 while (i < len && (digit = digit(s.charAt(i++), radix)) >= 0
779 && (inRange = compareUnsigned(result, multmax) < 0
780 || result == multmax && digit < (int) (-radix * multmax))) {
781 result = radix * result + digit;
782 }
783 if (inRange && i == len && digit >= 0) {
784 return result;
785 }
786 }
787 if (digit < 0) {
788 throw NumberFormatException.forInputString(s, radix);
789 }
790 throw new NumberFormatException(String.format(
791 "String value %s exceeds range of unsigned long.", s));
792 }
793
794 /**
795 * Parses the {@link CharSequence} argument as an unsigned {@code long} in
796 * the specified {@code radix}, beginning at the specified
797 * {@code beginIndex} and extending to {@code endIndex - 1}.
798 *
799 * <p>The method does not take steps to guard against the
800 * {@code CharSequence} being mutated while parsing.
801 *
802 * @param s the {@code CharSequence} containing the unsigned
803 * {@code long} representation to be parsed
804 * @param beginIndex the beginning index, inclusive.
805 * @param endIndex the ending index, exclusive.
806 * @param radix the radix to be used while parsing {@code s}.
807 * @return the unsigned {@code long} represented by the subsequence in
808 * the specified radix.
809 * @throws NullPointerException if {@code s} is null.
810 * @throws IndexOutOfBoundsException if {@code beginIndex} is
811 * negative, or if {@code beginIndex} is greater than
812 * {@code endIndex} or if {@code endIndex} is greater than
813 * {@code s.length()}.
814 * @throws NumberFormatException if the {@code CharSequence} does not
815 * contain a parsable unsigned {@code long} in the specified
816 * {@code radix}, or if {@code radix} is either smaller than
817 * {@link java.lang.Character#MIN_RADIX} or larger than
818 * {@link java.lang.Character#MAX_RADIX}.
819 * @since 9
820 */
821 public static long parseUnsignedLong(CharSequence s, int beginIndex, int endIndex, int radix)
822 throws NumberFormatException {
823 Objects.requireNonNull(s);
824 Objects.checkFromToIndex(beginIndex, endIndex, s.length());
825
826 if (radix < Character.MIN_RADIX) {
827 throw new NumberFormatException(String.format(
828 "radix %s less than Character.MIN_RADIX", radix));
829 }
830
831 if (radix > Character.MAX_RADIX) {
832 throw new NumberFormatException(String.format(
833 "radix %s greater than Character.MAX_RADIX", radix));
834 }
835
836 /*
837 * While s can be concurrently modified, it is ensured that each
838 * of its characters is read at most once, from lower to higher indices.
839 * This is obtained by reading them using the pattern s.charAt(i++),
840 * and by not updating i anywhere else.
841 */
842 if (beginIndex == endIndex) {
843 throw NumberFormatException.forInputString("", radix);
844 }
845 int i = beginIndex;
846 char firstChar = s.charAt(i++);
847 if (firstChar == '-') {
848 throw new NumberFormatException(
849 "Illegal leading minus sign on unsigned string " + s + ".");
850 }
851 int digit = ~0xFF;
852 if (firstChar != '+') {
853 digit = digit(firstChar, radix);
854 }
855 if (digit >= 0 || digit == ~0xFF && endIndex - beginIndex > 1) {
856 long multmax = divideUnsigned(-1L, radix); // -1L is max unsigned long
857 long result = digit & 0xFF;
858 boolean inRange = true;
859 while (i < endIndex && (digit = digit(s.charAt(i++), radix)) >= 0
860 && (inRange = compareUnsigned(result, multmax) < 0
861 || result == multmax && digit < (int) (-radix * multmax))) {
862 result = radix * result + digit;
863 }
864 if (inRange && i == endIndex && digit >= 0) {
865 return result;
866 }
867 }
868 if (digit < 0) {
869 throw NumberFormatException.forCharSequence(s, beginIndex,
870 endIndex, i - (digit < -1 ? 0 : 1));
871 }
872 throw new NumberFormatException(String.format(
873 "String value %s exceeds range of unsigned long.", s));
874 }
875
876 /**
877 * Parses the string argument as an unsigned decimal {@code long}. The
878 * characters in the string must all be decimal digits, except
879 * that the first character may be an ASCII plus sign {@code
880 * '+'} ({@code '\u005Cu002B'}). The resulting integer value
881 * is returned, exactly as if the argument and the radix 10 were
882 * given as arguments to the {@link
883 * #parseUnsignedLong(java.lang.String, int)} method.
884 *
885 * @param s a {@code String} containing the unsigned {@code long}
886 * representation to be parsed
887 * @return the unsigned {@code long} value represented by the decimal string argument
888 * @throws NumberFormatException if the string does not contain a
889 * parsable unsigned integer.
890 * @since 1.8
891 */
892 public static long parseUnsignedLong(String s) throws NumberFormatException {
893 return parseUnsignedLong(s, 10);
894 }
895
896 /**
897 * Returns a {@code Long} object holding the value
898 * extracted from the specified {@code String} when parsed
899 * with the radix given by the second argument. The first
900 * argument is interpreted as representing a signed
901 * {@code long} in the radix specified by the second
902 * argument, exactly as if the arguments were given to the {@link
903 * #parseLong(java.lang.String, int)} method. The result is a
904 * {@code Long} object that represents the {@code long}
905 * value specified by the string.
906 *
907 * <p>In other words, this method returns a {@code Long} object equal
908 * to the value of:
909 *
910 * <blockquote>
911 * {@code Long.valueOf(Long.parseLong(s, radix))}
912 * </blockquote>
913 *
914 * @param s the string to be parsed
915 * @param radix the radix to be used in interpreting {@code s}
916 * @return a {@code Long} object holding the value
917 * represented by the string argument in the specified
918 * radix.
919 * @throws NumberFormatException If the {@code String} does not
920 * contain a parsable {@code long}.
921 */
922 public static Long valueOf(String s, int radix) throws NumberFormatException {
923 return Long.valueOf(parseLong(s, radix));
924 }
925
926 /**
927 * Returns a {@code Long} object holding the value
928 * of the specified {@code String}. The argument is
929 * interpreted as representing a signed decimal {@code long},
930 * exactly as if the argument were given to the {@link
931 * #parseLong(java.lang.String)} method. The result is a
932 * {@code Long} object that represents the integer value
933 * specified by the string.
934 *
935 * <p>In other words, this method returns a {@code Long} object
936 * equal to the value of:
937 *
938 * <blockquote>
939 * {@code Long.valueOf(Long.parseLong(s))}
940 * </blockquote>
941 *
942 * @param s the string to be parsed.
943 * @return a {@code Long} object holding the value
944 * represented by the string argument.
945 * @throws NumberFormatException If the string cannot be parsed
946 * as a {@code long}.
947 */
948 public static Long valueOf(String s) throws NumberFormatException
949 {
950 return Long.valueOf(parseLong(s, 10));
951 }
952
953 private static final class LongCache {
954 private LongCache() {}
955
956 @Stable
957 static final Long[] cache;
958 static Long[] archivedCache;
959
960 static {
961 int size = -(-128) + 127 + 1;
962
963 // Load and use the archived cache if it exists
964 CDS.initializeFromArchive(LongCache.class);
965 if (archivedCache == null) {
966 Long[] c = new Long[size];
967 long value = -128;
968 for(int i = 0; i < size; i++) {
969 c[i] = new Long(value++);
970 }
971 archivedCache = c;
972 }
973 cache = archivedCache;
974 assert cache.length == size;
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 public static Long valueOf(long l) {
996 final int offset = 128;
997 if (l >= -128 && l <= 127) { // will cache
998 return LongCache.cache[(int)l + offset];
999 }
1000 return new Long(l);
1001 }
1002
1003 /**
1004 * Decodes a {@code String} into a {@code Long}.
1005 * Accepts decimal, hexadecimal, and octal numbers given by the
1006 * following grammar:
1007 *
1008 * <blockquote>
1009 * <dl>
1010 * <dt><i>DecodableString:</i>
1011 * <dd><i>Sign<sub>opt</sub> DecimalNumeral</i>
1012 * <dd><i>Sign<sub>opt</sub></i> {@code 0x} <i>HexDigits</i>
1013 * <dd><i>Sign<sub>opt</sub></i> {@code 0X} <i>HexDigits</i>
1014 * <dd><i>Sign<sub>opt</sub></i> {@code #} <i>HexDigits</i>
1015 * <dd><i>Sign<sub>opt</sub></i> {@code 0} <i>OctalDigits</i>
1016 *
1017 * <dt><i>Sign:</i>
1018 * <dd>{@code -}
1019 * <dd>{@code +}
1020 * </dl>
1021 * </blockquote>
1022 *
1023 * <i>DecimalNumeral</i>, <i>HexDigits</i>, and <i>OctalDigits</i>
1024 * are as defined in section {@jls 3.10.1} of
1025 * <cite>The Java Language Specification</cite>,
1026 * except that underscores are not accepted between digits.
1027 *
1028 * <p>The sequence of characters following an optional
1029 * sign and/or radix specifier ("{@code 0x}", "{@code 0X}",
1030 * "{@code #}", or leading zero) is parsed as by the {@code
1031 * Long.parseLong} method with the indicated radix (10, 16, or 8).
1032 * This sequence of characters must represent a positive value or
1033 * a {@link NumberFormatException} will be thrown. The result is
1034 * negated if first character of the specified {@code String} is
1035 * the minus sign. No whitespace characters are permitted in the
1036 * {@code String}.
1037 *
1038 * @param nm the {@code String} to decode.
1039 * @return a {@code Long} object holding the {@code long}
1040 * value represented by {@code nm}
1041 * @throws NumberFormatException if the {@code String} does not
1042 * contain a parsable {@code long}.
1043 * @see java.lang.Long#parseLong(String, int)
1044 * @since 1.2
1045 */
1046 public static Long decode(String nm) throws NumberFormatException {
1047 int radix = 10;
1048 int index = 0;
1049 boolean negative = false;
1050 long result;
1051
1052 if (nm.isEmpty())
1053 throw new NumberFormatException("Zero length string");
1054 char firstChar = nm.charAt(0);
1055 // Handle sign, if present
1056 if (firstChar == '-') {
1057 negative = true;
1058 index++;
1059 } else if (firstChar == '+')
1060 index++;
1061
1062 // Handle radix specifier, if present
1063 if (nm.startsWith("0x", index) || nm.startsWith("0X", index)) {
1064 index += 2;
1065 radix = 16;
1066 }
1067 else if (nm.startsWith("#", index)) {
1068 index ++;
1069 radix = 16;
1070 }
1071 else if (nm.startsWith("0", index) && nm.length() > 1 + index) {
1072 index ++;
1073 radix = 8;
1074 }
1075
1076 if (nm.startsWith("-", index) || nm.startsWith("+", index))
1077 throw new NumberFormatException("Sign character in wrong position");
1078
1079 try {
1080 result = parseLong(nm, index, nm.length(), radix);
1081 result = negative ? -result : result;
1082 } catch (NumberFormatException e) {
1083 // If number is Long.MIN_VALUE, we'll end up here. The next line
1084 // handles this case, and causes any genuine format error to be
1085 // rethrown.
1086 String constant = negative ? ("-" + nm.substring(index))
1087 : nm.substring(index);
1088 result = parseLong(constant, radix);
1089 }
1090 return result;
1091 }
1092
1093 /**
1094 * The value of the {@code Long}.
1095 *
1096 * @serial
1097 */
1098 private final long value;
1099
1100 /**
1101 * Constructs a newly allocated {@code Long} object that
1102 * represents the specified {@code long} argument.
1103 *
1104 * @param value the value to be represented by the
1105 * {@code Long} object.
1106 *
1107 * @deprecated
1108 * It is rarely appropriate to use this constructor. The static factory
1109 * {@link #valueOf(long)} is generally a better choice, as it is
1110 * likely to yield significantly better space and time performance.
1111 */
1112 @Deprecated(since="9", forRemoval = true)
1113 public Long(long value) {
1114 this.value = value;
1115 }
1116
1117 /**
1118 * Constructs a newly allocated {@code Long} object that
1119 * represents the {@code long} value indicated by the
1120 * {@code String} parameter. The string is converted to a
1121 * {@code long} value in exactly the manner used by the
1122 * {@code parseLong} method for radix 10.
1123 *
1124 * @param s the {@code String} to be converted to a
1125 * {@code Long}.
1126 * @throws NumberFormatException if the {@code String} does not
1127 * contain a parsable {@code long}.
1128 *
1129 * @deprecated
1130 * It is rarely appropriate to use this constructor.
1131 * Use {@link #parseLong(String)} to convert a string to a
1132 * {@code long} primitive, or use {@link #valueOf(String)}
1133 * to convert a string to a {@code Long} object.
1134 */
1135 @Deprecated(since="9", forRemoval = true)
1136 public Long(String s) throws NumberFormatException {
1137 this.value = parseLong(s, 10);
1138 }
1139
1140 /**
1141 * Returns the value of this {@code Long} as a {@code byte} after
1142 * a narrowing primitive conversion.
1143 * @jls 5.1.3 Narrowing Primitive Conversion
1144 */
1145 public byte byteValue() {
1146 return (byte)value;
1147 }
1148
1149 /**
1150 * Returns the value of this {@code Long} as a {@code short} after
1151 * a narrowing primitive conversion.
1152 * @jls 5.1.3 Narrowing Primitive Conversion
1153 */
1154 public short shortValue() {
1155 return (short)value;
1156 }
1157
1158 /**
1159 * Returns the value of this {@code Long} as an {@code int} after
1160 * a narrowing primitive conversion.
1161 * @jls 5.1.3 Narrowing Primitive Conversion
1162 */
1163 public int intValue() {
1164 return (int)value;
1165 }
1166
1167 /**
1168 * Returns the value of this {@code Long} as a
1169 * {@code long} value.
1170 */
1171 @IntrinsicCandidate
1172 public long longValue() {
1173 return value;
1174 }
1175
1176 /**
1177 * Returns the value of this {@code Long} as a {@code float} after
1178 * a widening primitive conversion.
1179 * @jls 5.1.2 Widening Primitive Conversion
1180 */
1181 public float floatValue() {
1182 return (float)value;
1183 }
1184
1185 /**
1186 * Returns the value of this {@code Long} as a {@code double}
1187 * after a widening primitive conversion.
1188 * @jls 5.1.2 Widening Primitive Conversion
1189 */
1190 public double doubleValue() {
1191 return (double)value;
1192 }
1193
1194 /**
1195 * Returns a {@code String} object representing this
1196 * {@code Long}'s value. The value is converted to signed
1197 * decimal representation and returned as a string, exactly as if
1198 * the {@code long} value were given as an argument to the
1199 * {@link java.lang.Long#toString(long)} method.
1200 *
1201 * @return a string representation of the value of this object in
1202 * base 10.
1203 */
1204 public String toString() {
1205 return toString(value);
1206 }
1207
1208 /**
1209 * Returns a hash code for this {@code Long}. The result is
1210 * the exclusive OR of the two halves of the primitive
1211 * {@code long} value held by this {@code Long}
1212 * object. That is, the hashcode is the value of the expression:
1213 *
1214 * <blockquote>
1215 * {@code (int)(this.longValue()^(this.longValue()>>>32))}
1216 * </blockquote>
1217 *
1218 * @return a hash code value for this object.
1219 */
1220 @Override
1221 public int hashCode() {
1222 return Long.hashCode(value);
1223 }
1224
1225 /**
1226 * Returns a hash code for a {@code long} value; compatible with
1227 * {@code Long.hashCode()}.
1228 *
1229 * @param value the value to hash
1230 * @return a hash code value for a {@code long} value.
1231 * @since 1.8
1232 */
1233 public static int hashCode(long value) {
1234 return (int)(value ^ (value >>> 32));
1235 }
1236
1237 /**
1238 * Compares this object to the specified object. The result is
1239 * {@code true} if and only if the argument is not
1240 * {@code null} and is a {@code Long} object that
1241 * contains the same {@code long} value as this object.
1242 *
1243 * @param obj the object to compare with.
1244 * @return {@code true} if the objects are the same;
1245 * {@code false} otherwise.
1246 */
1247 public boolean equals(Object obj) {
1248 if (obj instanceof Long ell) {
1249 return value == ell.longValue();
1250 }
1251 return false;
1252 }
1253
1254 /**
1255 * Determines the {@code long} value of the system property
1256 * with the specified name.
1257 *
1258 * <p>The first argument is treated as the name of a system
1259 * property. System properties are accessible through the {@link
1260 * java.lang.System#getProperty(java.lang.String)} method. The
1261 * string value of this property is then interpreted as a {@code
1262 * long} value using the grammar supported by {@link Long#decode decode}
1263 * and a {@code Long} object representing this value is returned.
1264 *
1265 * <p>If there is no property with the specified name, if the
1266 * specified name is empty or {@code null}, or if the property
1267 * does not have the correct numeric format, then {@code null} is
1268 * returned.
1269 *
1270 * <p>In other words, this method returns a {@code Long} object
1271 * equal to the value of:
1272 *
1273 * <blockquote>
1274 * {@code getLong(nm, null)}
1275 * </blockquote>
1276 *
1277 * @param nm property name.
1278 * @return the {@code Long} value of the property.
1279 * @throws SecurityException for the same reasons as
1280 * {@link System#getProperty(String) System.getProperty}
1281 * @see java.lang.System#getProperty(java.lang.String)
1282 * @see java.lang.System#getProperty(java.lang.String, java.lang.String)
1283 */
1284 public static Long getLong(String nm) {
1285 return getLong(nm, null);
1286 }
1287
1288 /**
1289 * Determines the {@code long} value of the system property
1290 * with the specified name.
1291 *
1292 * <p>The first argument is treated as the name of a system
1293 * property. System properties are accessible through the {@link
1294 * java.lang.System#getProperty(java.lang.String)} method. The
1295 * string value of this property is then interpreted as a {@code
1296 * long} value using the grammar supported by {@link Long#decode decode}
1297 * and a {@code Long} object representing this value is returned.
1298 *
1299 * <p>The second argument is the default value. A {@code Long} object
1300 * that represents the value of the second argument is returned if there
1301 * is no property of the specified name, if the property does not have
1302 * the correct numeric format, or if the specified name is empty or null.
1303 *
1304 * <p>In other words, this method returns a {@code Long} object equal
1305 * to the value of:
1306 *
1307 * <blockquote>
1308 * {@code getLong(nm, Long.valueOf(val))}
1309 * </blockquote>
1310 *
1311 * but in practice it may be implemented in a manner such as:
1312 *
1313 * <blockquote><pre>
1314 * Long result = getLong(nm, null);
1315 * return (result == null) ? Long.valueOf(val) : result;
1316 * </pre></blockquote>
1317 *
1318 * to avoid the unnecessary allocation of a {@code Long} object when
1319 * the default value is not needed.
1320 *
1321 * @param nm property name.
1322 * @param val default value.
1323 * @return the {@code Long} value of the property.
1324 * @throws SecurityException for the same reasons as
1325 * {@link System#getProperty(String) System.getProperty}
1326 * @see java.lang.System#getProperty(java.lang.String)
1327 * @see java.lang.System#getProperty(java.lang.String, java.lang.String)
1328 */
1329 public static Long getLong(String nm, long val) {
1330 Long result = Long.getLong(nm, null);
1331 return (result == null) ? Long.valueOf(val) : result;
1332 }
1333
1334 /**
1335 * Returns the {@code long} value of the system property with
1336 * the specified name. The first argument is treated as the name
1337 * of a system property. System properties are accessible through
1338 * the {@link java.lang.System#getProperty(java.lang.String)}
1339 * method. The string value of this property is then interpreted
1340 * as a {@code long} value, as per the
1341 * {@link Long#decode decode} method, and a {@code Long} object
1342 * representing this value is returned; in summary:
1343 *
1344 * <ul>
1345 * <li>If the property value begins with the two ASCII characters
1346 * {@code 0x} or the ASCII character {@code #}, not followed by
1347 * a minus sign, then the rest of it is parsed as a hexadecimal integer
1348 * exactly as for the method {@link #valueOf(java.lang.String, int)}
1349 * with radix 16.
1350 * <li>If the property value begins with the ASCII character
1351 * {@code 0} followed by another character, it is parsed as
1352 * an octal integer exactly as by the method {@link
1353 * #valueOf(java.lang.String, int)} with radix 8.
1354 * <li>Otherwise the property value is parsed as a decimal
1355 * integer exactly as by the method
1356 * {@link #valueOf(java.lang.String, int)} with radix 10.
1357 * </ul>
1358 *
1359 * <p>Note that, in every case, neither {@code L}
1360 * ({@code '\u005Cu004C'}) nor {@code l}
1361 * ({@code '\u005Cu006C'}) is permitted to appear at the end
1362 * of the property value as a type indicator, as would be
1363 * permitted in Java programming language source code.
1364 *
1365 * <p>The second argument is the default value. The default value is
1366 * returned if there is no property of the specified name, if the
1367 * property does not have the correct numeric format, or if the
1368 * specified name is empty or {@code null}.
1369 *
1370 * @param nm property name.
1371 * @param val default value.
1372 * @return the {@code Long} value of the property.
1373 * @throws SecurityException for the same reasons as
1374 * {@link System#getProperty(String) System.getProperty}
1375 * @see System#getProperty(java.lang.String)
1376 * @see System#getProperty(java.lang.String, java.lang.String)
1377 */
1378 public static Long getLong(String nm, Long val) {
1379 String v = null;
1380 try {
1381 v = System.getProperty(nm);
1382 } catch (IllegalArgumentException | NullPointerException e) {
1383 }
1384 if (v != null) {
1385 try {
1386 return Long.decode(v);
1387 } catch (NumberFormatException e) {
1388 }
1389 }
1390 return val;
1391 }
1392
1393 /**
1394 * Compares two {@code Long} objects numerically.
1395 *
1396 * @param anotherLong the {@code Long} to be compared.
1397 * @return the value {@code 0} if this {@code Long} is
1398 * equal to the argument {@code Long}; a value less than
1399 * {@code 0} if this {@code Long} is numerically less
1400 * than the argument {@code Long}; and a value greater
1401 * than {@code 0} if this {@code Long} is numerically
1402 * greater than the argument {@code Long} (signed
1403 * comparison).
1404 * @since 1.2
1405 */
1406 public int compareTo(Long anotherLong) {
1407 return compare(this.value, anotherLong.value);
1408 }
1409
1410 /**
1411 * Compares two {@code long} values numerically.
1412 * The value returned is identical to what would be returned by:
1413 * <pre>
1414 * Long.valueOf(x).compareTo(Long.valueOf(y))
1415 * </pre>
1416 *
1417 * @param x the first {@code long} to compare
1418 * @param y the second {@code long} to compare
1419 * @return the value {@code 0} if {@code x == y};
1420 * a value less than {@code 0} if {@code x < y}; and
1421 * a value greater than {@code 0} if {@code x > y}
1422 * @since 1.7
1423 */
1424 public static int compare(long x, long y) {
1425 return (x < y) ? -1 : ((x == y) ? 0 : 1);
1426 }
1427
1428 /**
1429 * Compares two {@code long} values numerically treating the values
1430 * as unsigned.
1431 *
1432 * @param x the first {@code long} to compare
1433 * @param y the second {@code long} to compare
1434 * @return the value {@code 0} if {@code x == y}; a value less
1435 * than {@code 0} if {@code x < y} as unsigned values; and
1436 * a value greater than {@code 0} if {@code x > y} as
1437 * unsigned values
1438 * @since 1.8
1439 */
1440 @IntrinsicCandidate
1441 public static int compareUnsigned(long x, long y) {
1442 return compare(x + MIN_VALUE, y + MIN_VALUE);
1443 }
1444
1445
1446 /**
1447 * Returns the unsigned quotient of dividing the first argument by
1448 * the second where each argument and the result is interpreted as
1449 * an unsigned value.
1450 *
1451 * <p>Note that in two's complement arithmetic, the three other
1452 * basic arithmetic operations of add, subtract, and multiply are
1453 * bit-wise identical if the two operands are regarded as both
1454 * being signed or both being unsigned. Therefore separate {@code
1455 * addUnsigned}, etc. methods are not provided.
1456 *
1457 * @param dividend the value to be divided
1458 * @param divisor the value doing the dividing
1459 * @return the unsigned quotient of the first argument divided by
1460 * the second argument
1461 * @see #remainderUnsigned
1462 * @since 1.8
1463 */
1464 @IntrinsicCandidate
1465 public static long divideUnsigned(long dividend, long divisor) {
1466 /* See Hacker's Delight (2nd ed), section 9.3 */
1467 if (divisor >= 0) {
1468 final long q = (dividend >>> 1) / divisor << 1;
1469 final long r = dividend - q * divisor;
1470 return q + ((r | ~(r - divisor)) >>> (Long.SIZE - 1));
1471 }
1472 return (dividend & ~(dividend - divisor)) >>> (Long.SIZE - 1);
1473 }
1474
1475 /**
1476 * Returns the unsigned remainder from dividing the first argument
1477 * by the second where each argument and the result is interpreted
1478 * as an unsigned value.
1479 *
1480 * @param dividend the value to be divided
1481 * @param divisor the value doing the dividing
1482 * @return the unsigned remainder of the first argument divided by
1483 * the second argument
1484 * @see #divideUnsigned
1485 * @since 1.8
1486 */
1487 @IntrinsicCandidate
1488 public static long remainderUnsigned(long dividend, long divisor) {
1489 /* See Hacker's Delight (2nd ed), section 9.3 */
1490 if (divisor >= 0) {
1491 final long q = (dividend >>> 1) / divisor << 1;
1492 final long r = dividend - q * divisor;
1493 /*
1494 * Here, 0 <= r < 2 * divisor
1495 * (1) When 0 <= r < divisor, the remainder is simply r.
1496 * (2) Otherwise the remainder is r - divisor.
1497 *
1498 * In case (1), r - divisor < 0. Applying ~ produces a long with
1499 * sign bit 0, so >> produces 0. The returned value is thus r.
1500 *
1501 * In case (2), a similar reasoning shows that >> produces -1,
1502 * so the returned value is r - divisor.
1503 */
1504 return r - ((~(r - divisor) >> (Long.SIZE - 1)) & divisor);
1505 }
1506 /*
1507 * (1) When dividend >= 0, the remainder is dividend.
1508 * (2) Otherwise
1509 * (2.1) When dividend < divisor, the remainder is dividend.
1510 * (2.2) Otherwise the remainder is dividend - divisor
1511 *
1512 * A reasoning similar to the above shows that the returned value
1513 * is as expected.
1514 */
1515 return dividend - (((dividend & ~(dividend - divisor)) >> (Long.SIZE - 1)) & divisor);
1516 }
1517
1518 // Bit Twiddling
1519
1520 /**
1521 * The number of bits used to represent a {@code long} value in two's
1522 * complement binary form.
1523 *
1524 * @since 1.5
1525 */
1526 @Native public static final int SIZE = 64;
1527
1528 /**
1529 * The number of bytes used to represent a {@code long} value in two's
1530 * complement binary form.
1531 *
1532 * @since 1.8
1533 */
1534 public static final int BYTES = SIZE / Byte.SIZE;
1535
1536 /**
1537 * Returns a {@code long} value with at most a single one-bit, in the
1538 * position of the highest-order ("leftmost") one-bit in the specified
1539 * {@code long} value. Returns zero if the specified value has no
1540 * one-bits in its two's complement binary representation, that is, if it
1541 * is equal to zero.
1542 *
1543 * @param i the value whose highest one bit is to be computed
1544 * @return a {@code long} value with a single one-bit, in the position
1545 * of the highest-order one-bit in the specified value, or zero if
1546 * the specified value is itself equal to zero.
1547 * @since 1.5
1548 */
1549 public static long highestOneBit(long i) {
1550 return i & (MIN_VALUE >>> numberOfLeadingZeros(i));
1551 }
1552
1553 /**
1554 * Returns a {@code long} value with at most a single one-bit, in the
1555 * position of the lowest-order ("rightmost") one-bit in the specified
1556 * {@code long} value. Returns zero if the specified value has no
1557 * one-bits in its two's complement binary representation, that is, if it
1558 * is equal to zero.
1559 *
1560 * @param i the value whose lowest one bit is to be computed
1561 * @return a {@code long} value with a single one-bit, in the position
1562 * of the lowest-order one-bit in the specified value, or zero if
1563 * the specified value is itself equal to zero.
1564 * @since 1.5
1565 */
1566 public static long lowestOneBit(long i) {
1567 // HD, Section 2-1
1568 return i & -i;
1569 }
1570
1571 /**
1572 * Returns the number of zero bits preceding the highest-order
1573 * ("leftmost") one-bit in the two's complement binary representation
1574 * of the specified {@code long} value. Returns 64 if the
1575 * specified value has no one-bits in its two's complement representation,
1576 * in other words if it is equal to zero.
1577 *
1578 * <p>Note that this method is closely related to the logarithm base 2.
1579 * For all positive {@code long} values x:
1580 * <ul>
1581 * <li>floor(log<sub>2</sub>(x)) = {@code 63 - numberOfLeadingZeros(x)}
1582 * <li>ceil(log<sub>2</sub>(x)) = {@code 64 - numberOfLeadingZeros(x - 1)}
1583 * </ul>
1584 *
1585 * @param i the value whose number of leading zeros is to be computed
1586 * @return the number of zero bits preceding the highest-order
1587 * ("leftmost") one-bit in the two's complement binary representation
1588 * of the specified {@code long} value, or 64 if the value
1589 * is equal to zero.
1590 * @since 1.5
1591 */
1592 @IntrinsicCandidate
1593 public static int numberOfLeadingZeros(long i) {
1594 int x = (int)(i >>> 32);
1595 return x == 0 ? 32 + Integer.numberOfLeadingZeros((int)i)
1596 : Integer.numberOfLeadingZeros(x);
1597 }
1598
1599 /**
1600 * Returns the number of zero bits following the lowest-order ("rightmost")
1601 * one-bit in the two's complement binary representation of the specified
1602 * {@code long} value. Returns 64 if the specified value has no
1603 * one-bits in its two's complement representation, in other words if it is
1604 * equal to zero.
1605 *
1606 * @param i the value whose number of trailing zeros is to be computed
1607 * @return the number of zero bits following the lowest-order ("rightmost")
1608 * one-bit in the two's complement binary representation of the
1609 * specified {@code long} value, or 64 if the value is equal
1610 * to zero.
1611 * @since 1.5
1612 */
1613 @IntrinsicCandidate
1614 public static int numberOfTrailingZeros(long i) {
1615 int x = (int)i;
1616 return x == 0 ? 32 + Integer.numberOfTrailingZeros((int)(i >>> 32))
1617 : Integer.numberOfTrailingZeros(x);
1618 }
1619
1620 /**
1621 * Returns the number of one-bits in the two's complement binary
1622 * representation of the specified {@code long} value. This function is
1623 * sometimes referred to as the <i>population count</i>.
1624 *
1625 * @param i the value whose bits are to be counted
1626 * @return the number of one-bits in the two's complement binary
1627 * representation of the specified {@code long} value.
1628 * @since 1.5
1629 */
1630 @IntrinsicCandidate
1631 public static int bitCount(long i) {
1632 // HD, Figure 5-2
1633 i = i - ((i >>> 1) & 0x5555555555555555L);
1634 i = (i & 0x3333333333333333L) + ((i >>> 2) & 0x3333333333333333L);
1635 i = (i + (i >>> 4)) & 0x0f0f0f0f0f0f0f0fL;
1636 i = i + (i >>> 8);
1637 i = i + (i >>> 16);
1638 i = i + (i >>> 32);
1639 return (int)i & 0x7f;
1640 }
1641
1642 /**
1643 * Returns the value obtained by rotating the two's complement binary
1644 * representation of the specified {@code long} value left by the
1645 * specified number of bits. (Bits shifted out of the left hand, or
1646 * high-order, side reenter on the right, or low-order.)
1647 *
1648 * <p>Note that left rotation with a negative distance is equivalent to
1649 * right rotation: {@code rotateLeft(val, -distance) == rotateRight(val,
1650 * distance)}. Note also that rotation by any multiple of 64 is a
1651 * no-op, so all but the last six bits of the rotation distance can be
1652 * ignored, even if the distance is negative: {@code rotateLeft(val,
1653 * distance) == rotateLeft(val, distance & 0x3F)}.
1654 *
1655 * @param i the value whose bits are to be rotated left
1656 * @param distance the number of bit positions to rotate left
1657 * @return the value obtained by rotating the two's complement binary
1658 * representation of the specified {@code long} value left by the
1659 * specified number of bits.
1660 * @since 1.5
1661 */
1662 public static long rotateLeft(long i, int distance) {
1663 return (i << distance) | (i >>> -distance);
1664 }
1665
1666 /**
1667 * Returns the value obtained by rotating the two's complement binary
1668 * representation of the specified {@code long} value right by the
1669 * specified number of bits. (Bits shifted out of the right hand, or
1670 * low-order, side reenter on the left, or high-order.)
1671 *
1672 * <p>Note that right rotation with a negative distance is equivalent to
1673 * left rotation: {@code rotateRight(val, -distance) == rotateLeft(val,
1674 * distance)}. Note also that rotation by any multiple of 64 is a
1675 * no-op, so all but the last six bits of the rotation distance can be
1676 * ignored, even if the distance is negative: {@code rotateRight(val,
1677 * distance) == rotateRight(val, distance & 0x3F)}.
1678 *
1679 * @param i the value whose bits are to be rotated right
1680 * @param distance the number of bit positions to rotate right
1681 * @return the value obtained by rotating the two's complement binary
1682 * representation of the specified {@code long} value right by the
1683 * specified number of bits.
1684 * @since 1.5
1685 */
1686 public static long rotateRight(long i, int distance) {
1687 return (i >>> distance) | (i << -distance);
1688 }
1689
1690 /**
1691 * Returns the value obtained by reversing the order of the bits in the
1692 * two's complement binary representation of the specified {@code long}
1693 * value.
1694 *
1695 * @param i the value to be reversed
1696 * @return the value obtained by reversing order of the bits in the
1697 * specified {@code long} value.
1698 * @since 1.5
1699 */
1700 @IntrinsicCandidate
1701 public static long reverse(long i) {
1702 // HD, Figure 7-1
1703 i = (i & 0x5555555555555555L) << 1 | (i >>> 1) & 0x5555555555555555L;
1704 i = (i & 0x3333333333333333L) << 2 | (i >>> 2) & 0x3333333333333333L;
1705 i = (i & 0x0f0f0f0f0f0f0f0fL) << 4 | (i >>> 4) & 0x0f0f0f0f0f0f0f0fL;
1706
1707 return reverseBytes(i);
1708 }
1709
1710 /**
1711 * Returns the value obtained by compressing the bits of the
1712 * specified {@code long} value, {@code i}, in accordance with
1713 * the specified bit mask.
1714 * <p>
1715 * For each one-bit value {@code mb} of the mask, from least
1716 * significant to most significant, the bit value of {@code i} at
1717 * the same bit location as {@code mb} is assigned to the compressed
1718 * value contiguously starting from the least significant bit location.
1719 * All the upper remaining bits of the compressed value are set
1720 * to zero.
1721 *
1722 * @apiNote
1723 * Consider the simple case of compressing the digits of a hexadecimal
1724 * value:
1725 * {@snippet lang="java" :
1726 * // Compressing drink to food
1727 * compress(0xCAFEBABEL, 0xFF00FFF0L) == 0xCABABL
1728 * }
1729 * Starting from the least significant hexadecimal digit at position 0
1730 * from the right, the mask {@code 0xFF00FFF0} selects hexadecimal digits
1731 * at positions 1, 2, 3, 6 and 7 of {@code 0xCAFEBABE}. The selected digits
1732 * occur in the resulting compressed value contiguously from digit position
1733 * 0 in the same order.
1734 * <p>
1735 * The following identities all return {@code true} and are helpful to
1736 * understand the behaviour of {@code compress}:
1737 * {@snippet lang="java" :
1738 * // Returns 1 if the bit at position n is one
1739 * compress(x, 1L << n) == (x >> n & 1)
1740 *
1741 * // Logical shift right
1742 * compress(x, -1L << n) == x >>> n
1743 *
1744 * // Any bits not covered by the mask are ignored
1745 * compress(x, m) == compress(x & m, m)
1746 *
1747 * // Compressing a value by itself
1748 * compress(m, m) == (m == -1 || m == 0) ? m : (1L << bitCount(m)) - 1
1749 *
1750 * // Expanding then compressing with the same mask
1751 * compress(expand(x, m), m) == x & compress(m, m)
1752 * }
1753 * <p>
1754 * The Sheep And Goats (SAG) operation (see Hacker's Delight, Second Edition, section 7.7)
1755 * can be implemented as follows:
1756 * {@snippet lang="java" :
1757 * long compressLeft(long i, long mask) {
1758 * // This implementation follows the description in Hacker's Delight which
1759 * // is informative. A more optimal implementation is:
1760 * // Long.compress(i, mask) << -Long.bitCount(mask)
1761 * return Long.reverse(
1762 * Long.compress(Long.reverse(i), Long.reverse(mask)));
1763 * }
1764 *
1765 * long sag(long i, long mask) {
1766 * return compressLeft(i, mask) | Long.compress(i, ~mask);
1767 * }
1768 *
1769 * // Separate the sheep from the goats
1770 * sag(0x00000000_CAFEBABEL, 0xFFFFFFFF_FF00FFF0L) == 0x00000000_CABABFEEL
1771 * }
1772 *
1773 * @param i the value whose bits are to be compressed
1774 * @param mask the bit mask
1775 * @return the compressed value
1776 * @see #expand
1777 * @since 19
1778 */
1779 @IntrinsicCandidate
1780 public static long compress(long i, long mask) {
1781 // See Hacker's Delight (2nd ed) section 7.4 Compress, or Generalized Extract
1782
1783 i = i & mask; // Clear irrelevant bits
1784 long maskCount = ~mask << 1; // Count 0's to right
1785
1786 for (int j = 0; j < 6; j++) {
1787 // Parallel prefix
1788 // Mask prefix identifies bits of the mask that have an odd number of 0's to the right
1789 long maskPrefix = parallelSuffix(maskCount);
1790 // Bits to move
1791 long maskMove = maskPrefix & mask;
1792 // Compress mask
1793 mask = (mask ^ maskMove) | (maskMove >>> (1 << j));
1794 // Bits of i to be moved
1795 long t = i & maskMove;
1796 // Compress i
1797 i = (i ^ t) | (t >>> (1 << j));
1798 // Adjust the mask count by identifying bits that have 0 to the right
1799 maskCount = maskCount & ~maskPrefix;
1800 }
1801 return i;
1802 }
1803
1804 /**
1805 * Returns the value obtained by expanding the bits of the
1806 * specified {@code long} value, {@code i}, in accordance with
1807 * the specified bit mask.
1808 * <p>
1809 * For each one-bit value {@code mb} of the mask, from least
1810 * significant to most significant, the next contiguous bit value
1811 * of {@code i} starting at the least significant bit is assigned
1812 * to the expanded value at the same bit location as {@code mb}.
1813 * All other remaining bits of the expanded value are set to zero.
1814 *
1815 * @apiNote
1816 * Consider the simple case of expanding the digits of a hexadecimal
1817 * value:
1818 * {@snippet lang="java" :
1819 * expand(0x0000CABABL, 0xFF00FFF0L) == 0xCA00BAB0L
1820 * }
1821 * Starting from the least significant hexadecimal digit at position 0
1822 * from the right, the mask {@code 0xFF00FFF0} selects the first five
1823 * hexadecimal digits of {@code 0x0000CABAB}. The selected digits occur
1824 * in the resulting expanded value in order at positions 1, 2, 3, 6, and 7.
1825 * <p>
1826 * The following identities all return {@code true} and are helpful to
1827 * understand the behaviour of {@code expand}:
1828 * {@snippet lang="java" :
1829 * // Logically shift right the bit at position 0
1830 * expand(x, 1L << n) == (x & 1) << n
1831 *
1832 * // Logically shift right
1833 * expand(x, -1L << n) == x << n
1834 *
1835 * // Expanding all bits returns the mask
1836 * expand(-1L, m) == m
1837 *
1838 * // Any bits not covered by the mask are ignored
1839 * expand(x, m) == expand(x, m) & m
1840 *
1841 * // Compressing then expanding with the same mask
1842 * expand(compress(x, m), m) == x & m
1843 * }
1844 * <p>
1845 * The select operation for determining the position of the one-bit with
1846 * index {@code n} in a {@code long} value can be implemented as follows:
1847 * {@snippet lang="java" :
1848 * long select(long i, long n) {
1849 * // the one-bit in i (the mask) with index n
1850 * long nthBit = Long.expand(1L << n, i);
1851 * // the bit position of the one-bit with index n
1852 * return Long.numberOfTrailingZeros(nthBit);
1853 * }
1854 *
1855 * // The one-bit with index 0 is at bit position 1
1856 * select(0b10101010_10101010, 0) == 1
1857 * // The one-bit with index 3 is at bit position 7
1858 * select(0b10101010_10101010, 3) == 7
1859 * }
1860 *
1861 * @param i the value whose bits are to be expanded
1862 * @param mask the bit mask
1863 * @return the expanded value
1864 * @see #compress
1865 * @since 19
1866 */
1867 @IntrinsicCandidate
1868 public static long expand(long i, long mask) {
1869 // Save original mask
1870 long originalMask = mask;
1871 // Count 0's to right
1872 long maskCount = ~mask << 1;
1873 long maskPrefix = parallelSuffix(maskCount);
1874 // Bits to move
1875 long maskMove1 = maskPrefix & mask;
1876 // Compress mask
1877 mask = (mask ^ maskMove1) | (maskMove1 >>> (1 << 0));
1878 maskCount = maskCount & ~maskPrefix;
1879
1880 maskPrefix = parallelSuffix(maskCount);
1881 // Bits to move
1882 long maskMove2 = maskPrefix & mask;
1883 // Compress mask
1884 mask = (mask ^ maskMove2) | (maskMove2 >>> (1 << 1));
1885 maskCount = maskCount & ~maskPrefix;
1886
1887 maskPrefix = parallelSuffix(maskCount);
1888 // Bits to move
1889 long maskMove3 = maskPrefix & mask;
1890 // Compress mask
1891 mask = (mask ^ maskMove3) | (maskMove3 >>> (1 << 2));
1892 maskCount = maskCount & ~maskPrefix;
1893
1894 maskPrefix = parallelSuffix(maskCount);
1895 // Bits to move
1896 long maskMove4 = maskPrefix & mask;
1897 // Compress mask
1898 mask = (mask ^ maskMove4) | (maskMove4 >>> (1 << 3));
1899 maskCount = maskCount & ~maskPrefix;
1900
1901 maskPrefix = parallelSuffix(maskCount);
1902 // Bits to move
1903 long maskMove5 = maskPrefix & mask;
1904 // Compress mask
1905 mask = (mask ^ maskMove5) | (maskMove5 >>> (1 << 4));
1906 maskCount = maskCount & ~maskPrefix;
1907
1908 maskPrefix = parallelSuffix(maskCount);
1909 // Bits to move
1910 long maskMove6 = maskPrefix & mask;
1911
1912 long t = i << (1 << 5);
1913 i = (i & ~maskMove6) | (t & maskMove6);
1914 t = i << (1 << 4);
1915 i = (i & ~maskMove5) | (t & maskMove5);
1916 t = i << (1 << 3);
1917 i = (i & ~maskMove4) | (t & maskMove4);
1918 t = i << (1 << 2);
1919 i = (i & ~maskMove3) | (t & maskMove3);
1920 t = i << (1 << 1);
1921 i = (i & ~maskMove2) | (t & maskMove2);
1922 t = i << (1 << 0);
1923 i = (i & ~maskMove1) | (t & maskMove1);
1924
1925 // Clear irrelevant bits
1926 return i & originalMask;
1927 }
1928
1929 @ForceInline
1930 private static long parallelSuffix(long maskCount) {
1931 long maskPrefix = maskCount ^ (maskCount << 1);
1932 maskPrefix = maskPrefix ^ (maskPrefix << 2);
1933 maskPrefix = maskPrefix ^ (maskPrefix << 4);
1934 maskPrefix = maskPrefix ^ (maskPrefix << 8);
1935 maskPrefix = maskPrefix ^ (maskPrefix << 16);
1936 maskPrefix = maskPrefix ^ (maskPrefix << 32);
1937 return maskPrefix;
1938 }
1939
1940 /**
1941 * Returns the signum function of the specified {@code long} value. (The
1942 * return value is -1 if the specified value is negative; 0 if the
1943 * specified value is zero; and 1 if the specified value is positive.)
1944 *
1945 * @param i the value whose signum is to be computed
1946 * @return the signum function of the specified {@code long} value.
1947 * @since 1.5
1948 */
1949 public static int signum(long i) {
1950 // HD, Section 2-7
1951 return (int) ((i >> 63) | (-i >>> 63));
1952 }
1953
1954 /**
1955 * Returns the value obtained by reversing the order of the bytes in the
1956 * two's complement representation of the specified {@code long} value.
1957 *
1958 * @param i the value whose bytes are to be reversed
1959 * @return the value obtained by reversing the bytes in the specified
1960 * {@code long} value.
1961 * @since 1.5
1962 */
1963 @IntrinsicCandidate
1964 public static long reverseBytes(long i) {
1965 i = (i & 0x00ff00ff00ff00ffL) << 8 | (i >>> 8) & 0x00ff00ff00ff00ffL;
1966 return (i << 48) | ((i & 0xffff0000L) << 16) |
1967 ((i >>> 16) & 0xffff0000L) | (i >>> 48);
1968 }
1969
1970 /**
1971 * Adds two {@code long} values together as per the + operator.
1972 *
1973 * @param a the first operand
1974 * @param b the second operand
1975 * @return the sum of {@code a} and {@code b}
1976 * @see java.util.function.BinaryOperator
1977 * @since 1.8
1978 */
1979 public static long sum(long a, long b) {
1980 return a + b;
1981 }
1982
1983 /**
1984 * Returns the greater of two {@code long} values
1985 * as if by calling {@link Math#max(long, long) Math.max}.
1986 *
1987 * @param a the first operand
1988 * @param b the second operand
1989 * @return the greater of {@code a} and {@code b}
1990 * @see java.util.function.BinaryOperator
1991 * @since 1.8
1992 */
1993 public static long max(long a, long b) {
1994 return Math.max(a, b);
1995 }
1996
1997 /**
1998 * Returns the smaller of two {@code long} values
1999 * as if by calling {@link Math#min(long, long) Math.min}.
2000 *
2001 * @param a the first operand
2002 * @param b the second operand
2003 * @return the smaller of {@code a} and {@code b}
2004 * @see java.util.function.BinaryOperator
2005 * @since 1.8
2006 */
2007 public static long min(long a, long b) {
2008 return Math.min(a, b);
2009 }
2010
2011 /**
2012 * Returns an {@link Optional} containing the nominal descriptor for this
2013 * instance, which is the instance itself.
2014 *
2015 * @return an {@link Optional} describing the {@linkplain Long} instance
2016 * @since 12
2017 */
2018 @Override
2019 public Optional<Long> describeConstable() {
2020 return Optional.of(this);
2021 }
2022
2023 /**
2024 * Resolves this instance as a {@link ConstantDesc}, the result of which is
2025 * the instance itself.
2026 *
2027 * @param lookup ignored
2028 * @return the {@linkplain Long} instance
2029 * @since 12
2030 */
2031 @Override
2032 public Long resolveConstantDesc(MethodHandles.Lookup lookup) {
2033 return this;
2034 }
2035
2036 /** use serialVersionUID from JDK 1.0.2 for interoperability */
2037 @java.io.Serial
2038 @Native private static final long serialVersionUID = 4290774380558885855L;
2039 }