1 /*
2 * Copyright (c) 1994, 2024, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 package java.lang;
27
28 import java.lang.annotation.Native;
29 import java.lang.invoke.MethodHandles;
30 import java.lang.constant.Constable;
31 import java.lang.constant.ConstantDesc;
32 import java.math.*;
33 import java.util.Objects;
34 import java.util.Optional;
35
36 import jdk.internal.misc.CDS;
37 import jdk.internal.value.DeserializeConstructor;
38 import jdk.internal.util.DecimalDigits;
39 import jdk.internal.vm.annotation.ForceInline;
40 import jdk.internal.vm.annotation.IntrinsicCandidate;
41 import jdk.internal.vm.annotation.Stable;
42
43 import static java.lang.Character.digit;
44 import static java.lang.String.COMPACT_STRINGS;
45 import static java.lang.String.LATIN1;
46 import static java.lang.String.UTF16;
47
48 /**
49 * The {@code Long} class is the {@linkplain
50 * java.lang##wrapperClass wrapper class} for values of the primitive
51 * type {@code long}. An object of type {@code Long} contains a
52 * single field whose type is {@code long}.
53 *
54 * <p> In addition, this class provides several methods for converting
55 * a {@code long} to a {@code String} and a {@code String} to a {@code
56 * long}, as well as other constants and methods useful when dealing
57 * with a {@code long}.
58 *
59 * <p>This is a <a href="{@docRoot}/java.base/java/lang/doc-files/ValueBased.html">value-based</a>
60 * class; programmers should treat instances that are
61 * {@linkplain #equals(Object) equal} as interchangeable and should not
62 * use instances for synchronization, or unpredictable behavior may
63 * occur. For example, in a future release, synchronization may fail.
64 *
65 * <p>Implementation note: The implementations of the "bit twiddling"
66 * methods (such as {@link #highestOneBit(long) highestOneBit} and
67 * {@link #numberOfTrailingZeros(long) numberOfTrailingZeros}) are
68 * based on material from Henry S. Warren, Jr.'s <cite>Hacker's
69 * Delight</cite>, (Addison Wesley, 2002) and <cite>Hacker's
70 * Delight, Second Edition</cite>, (Pearson Education, 2013).
71 *
72 * @author Lee Boynton
73 * @author Arthur van Hoff
74 * @author Josh Bloch
75 * @author Joseph D. Darcy
76 * @since 1.0
77 */
78 @jdk.internal.MigratedValueClass
79 @jdk.internal.ValueBased
80 public final class Long extends Number
81 implements Comparable<Long>, Constable, ConstantDesc {
82 /**
83 * A constant holding the minimum value a {@code long} can
84 * have, -2<sup>63</sup>.
85 */
86 @Native public static final long MIN_VALUE = 0x8000000000000000L;
87
88 /**
89 * A constant holding the maximum value a {@code long} can
90 * have, 2<sup>63</sup>-1.
91 */
92 @Native public static final long MAX_VALUE = 0x7fffffffffffffffL;
93
94 /**
95 * The {@code Class} instance representing the primitive type
96 * {@code long}.
97 *
98 * @since 1.1
99 */
100 @SuppressWarnings("unchecked")
101 public static final Class<Long> TYPE = (Class<Long>) Class.getPrimitiveClass("long");
102
103 /**
104 * Returns a string representation of the first argument in the
105 * radix specified by the second argument.
106 *
107 * <p>If the radix is smaller than {@code Character.MIN_RADIX}
108 * or larger than {@code Character.MAX_RADIX}, then the radix
109 * {@code 10} is used instead.
110 *
111 * <p>If the first argument is negative, the first element of the
112 * result is the ASCII minus sign {@code '-'}
113 * ({@code '\u005Cu002d'}). If the first argument is not
114 * negative, no sign character appears in the result.
115 *
116 * <p>The remaining characters of the result represent the magnitude
117 * of the first argument. If the magnitude is zero, it is
118 * represented by a single zero character {@code '0'}
119 * ({@code '\u005Cu0030'}); otherwise, the first character of
120 * the representation of the magnitude will not be the zero
121 * character. The following ASCII characters are used as digits:
122 *
123 * <blockquote>
124 * {@code 0123456789abcdefghijklmnopqrstuvwxyz}
125 * </blockquote>
126 *
127 * These are {@code '\u005Cu0030'} through
128 * {@code '\u005Cu0039'} and {@code '\u005Cu0061'} through
129 * {@code '\u005Cu007a'}. If {@code radix} is
130 * <var>N</var>, then the first <var>N</var> of these characters
131 * are used as radix-<var>N</var> digits in the order shown. Thus,
132 * the digits for hexadecimal (radix 16) are
133 * {@code 0123456789abcdef}. If uppercase letters are
134 * desired, the {@link java.lang.String#toUpperCase()} method may
135 * be called on the result:
136 *
137 * <blockquote>
138 * {@code Long.toString(n, 16).toUpperCase()}
139 * </blockquote>
140 *
141 * @param i a {@code long} to be converted to a string.
142 * @param radix the radix to use in the string representation.
143 * @return a string representation of the argument in the specified radix.
144 * @see java.lang.Character#MAX_RADIX
145 * @see java.lang.Character#MIN_RADIX
146 */
147 public static String toString(long i, int radix) {
148 if (radix < Character.MIN_RADIX || radix > Character.MAX_RADIX)
149 radix = 10;
150 if (radix == 10)
151 return toString(i);
152
153 if (COMPACT_STRINGS) {
154 byte[] buf = new byte[65];
155 int charPos = 64;
156 boolean negative = (i < 0);
157
158 if (!negative) {
159 i = -i;
160 }
161
162 while (i <= -radix) {
163 buf[charPos--] = (byte)Integer.digits[(int)(-(i % radix))];
164 i = i / radix;
165 }
166 buf[charPos] = (byte)Integer.digits[(int)(-i)];
167
168 if (negative) {
169 buf[--charPos] = '-';
170 }
171 return StringLatin1.newString(buf, charPos, (65 - charPos));
172 }
173 return toStringUTF16(i, radix);
174 }
175
176 private static String toStringUTF16(long i, int radix) {
177 byte[] buf = new byte[65 * 2];
178 int charPos = 64;
179 boolean negative = (i < 0);
180 if (!negative) {
181 i = -i;
182 }
183 while (i <= -radix) {
184 StringUTF16.putChar(buf, charPos--, Integer.digits[(int)(-(i % radix))]);
185 i = i / radix;
186 }
187 StringUTF16.putChar(buf, charPos, Integer.digits[(int)(-i)]);
188 if (negative) {
189 StringUTF16.putChar(buf, --charPos, '-');
190 }
191 return StringUTF16.newString(buf, charPos, (65 - charPos));
192 }
193
194 /**
195 * Returns a string representation of the first argument as an
196 * unsigned integer value in the radix specified by the second
197 * argument.
198 *
199 * <p>If the radix is smaller than {@code Character.MIN_RADIX}
200 * or larger than {@code Character.MAX_RADIX}, then the radix
201 * {@code 10} is used instead.
202 *
203 * <p>Note that since the first argument is treated as an unsigned
204 * value, no leading sign character is printed.
205 *
206 * <p>If the magnitude is zero, it is represented by a single zero
207 * character {@code '0'} ({@code '\u005Cu0030'}); otherwise,
208 * the first character of the representation of the magnitude will
209 * not be the zero character.
210 *
211 * <p>The behavior of radixes and the characters used as digits
212 * are the same as {@link #toString(long, int) toString}.
213 *
214 * @param i an integer to be converted to an unsigned string.
215 * @param radix the radix to use in the string representation.
216 * @return an unsigned string representation of the argument in the specified radix.
217 * @see #toString(long, int)
218 * @since 1.8
219 */
220 public static String toUnsignedString(long i, int radix) {
221 if (i >= 0)
222 return toString(i, radix);
223 else {
224 return switch (radix) {
225 case 2 -> toBinaryString(i);
226 case 4 -> toUnsignedString0(i, 2);
227 case 8 -> toOctalString(i);
228 case 10 -> {
229 /*
230 * We can get the effect of an unsigned division by 10
231 * on a long value by first shifting right, yielding a
232 * positive value, and then dividing by 5. This
233 * allows the last digit and preceding digits to be
234 * isolated more quickly than by an initial conversion
235 * to BigInteger.
236 */
237 long quot = (i >>> 1) / 5;
238 long rem = i - quot * 10;
239 yield toString(quot) + rem;
240 }
241 case 16 -> toHexString(i);
242 case 32 -> toUnsignedString0(i, 5);
243 default -> toUnsignedBigInteger(i).toString(radix);
244 };
245 }
246 }
247
248 /**
249 * Return a BigInteger equal to the unsigned value of the
250 * argument.
251 */
252 private static BigInteger toUnsignedBigInteger(long i) {
253 if (i >= 0L)
254 return BigInteger.valueOf(i);
255 else {
256 int upper = (int) (i >>> 32);
257 int lower = (int) i;
258
259 // return (upper << 32) + lower
260 return (BigInteger.valueOf(Integer.toUnsignedLong(upper))).shiftLeft(32).
261 add(BigInteger.valueOf(Integer.toUnsignedLong(lower)));
262 }
263 }
264
265 /**
266 * Returns a string representation of the {@code long}
267 * argument as an unsigned integer in base 16.
268 *
269 * <p>The unsigned {@code long} value is the argument plus
270 * 2<sup>64</sup> if the argument is negative; otherwise, it is
271 * equal to the argument. This value is converted to a string of
272 * ASCII digits in hexadecimal (base 16) with no extra
273 * leading {@code 0}s.
274 *
275 * <p>The value of the argument can be recovered from the returned
276 * string {@code s} by calling {@link
277 * Long#parseUnsignedLong(String, int) Long.parseUnsignedLong(s,
278 * 16)}.
279 *
280 * <p>If the unsigned magnitude is zero, it is represented by a
281 * single zero character {@code '0'} ({@code '\u005Cu0030'});
282 * otherwise, the first character of the representation of the
283 * unsigned magnitude will not be the zero character. The
284 * following characters are used as hexadecimal digits:
285 *
286 * <blockquote>
287 * {@code 0123456789abcdef}
288 * </blockquote>
289 *
290 * These are the characters {@code '\u005Cu0030'} through
291 * {@code '\u005Cu0039'} and {@code '\u005Cu0061'} through
292 * {@code '\u005Cu0066'}. If uppercase letters are desired,
293 * the {@link java.lang.String#toUpperCase()} method may be called
294 * on the result:
295 *
296 * <blockquote>
297 * {@code Long.toHexString(n).toUpperCase()}
298 * </blockquote>
299 *
300 * @apiNote
301 * The {@link java.util.HexFormat} class provides formatting and parsing
302 * of byte arrays and primitives to return a string or adding to an {@link Appendable}.
303 * {@code HexFormat} formats and parses uppercase or lowercase hexadecimal characters,
304 * with leading zeros and for byte arrays includes for each byte
305 * a delimiter, prefix, and suffix.
306 *
307 * @param i a {@code long} to be converted to a string.
308 * @return the string representation of the unsigned {@code long}
309 * value represented by the argument in hexadecimal
310 * (base 16).
311 * @see java.util.HexFormat
312 * @see #parseUnsignedLong(String, int)
313 * @see #toUnsignedString(long, int)
314 * @since 1.0.2
315 */
316 public static String toHexString(long i) {
317 return toUnsignedString0(i, 4);
318 }
319
320 /**
321 * Returns a string representation of the {@code long}
322 * argument as an unsigned integer in base 8.
323 *
324 * <p>The unsigned {@code long} value is the argument plus
325 * 2<sup>64</sup> if the argument is negative; otherwise, it is
326 * equal to the argument. This value is converted to a string of
327 * ASCII digits in octal (base 8) with no extra leading
328 * {@code 0}s.
329 *
330 * <p>The value of the argument can be recovered from the returned
331 * string {@code s} by calling {@link
332 * Long#parseUnsignedLong(String, int) Long.parseUnsignedLong(s,
333 * 8)}.
334 *
335 * <p>If the unsigned magnitude is zero, it is represented by a
336 * single zero character {@code '0'} ({@code '\u005Cu0030'});
337 * otherwise, the first character of the representation of the
338 * unsigned magnitude will not be the zero character. The
339 * following characters are used as octal digits:
340 *
341 * <blockquote>
342 * {@code 01234567}
343 * </blockquote>
344 *
345 * These are the characters {@code '\u005Cu0030'} through
346 * {@code '\u005Cu0037'}.
347 *
348 * @param i a {@code long} to be converted to a string.
349 * @return the string representation of the unsigned {@code long}
350 * value represented by the argument in octal (base 8).
351 * @see #parseUnsignedLong(String, int)
352 * @see #toUnsignedString(long, int)
353 * @since 1.0.2
354 */
355 public static String toOctalString(long i) {
356 return toUnsignedString0(i, 3);
357 }
358
359 /**
360 * Returns a string representation of the {@code long}
361 * argument as an unsigned integer in base 2.
362 *
363 * <p>The unsigned {@code long} value is the argument plus
364 * 2<sup>64</sup> if the argument is negative; otherwise, it is
365 * equal to the argument. This value is converted to a string of
366 * ASCII digits in binary (base 2) with no extra leading
367 * {@code 0}s.
368 *
369 * <p>The value of the argument can be recovered from the returned
370 * string {@code s} by calling {@link
371 * Long#parseUnsignedLong(String, int) Long.parseUnsignedLong(s,
372 * 2)}.
373 *
374 * <p>If the unsigned magnitude is zero, it is represented by a
375 * single zero character {@code '0'} ({@code '\u005Cu0030'});
376 * otherwise, the first character of the representation of the
377 * unsigned magnitude will not be the zero character. The
378 * characters {@code '0'} ({@code '\u005Cu0030'}) and {@code
379 * '1'} ({@code '\u005Cu0031'}) are used as binary digits.
380 *
381 * @param i a {@code long} to be converted to a string.
382 * @return the string representation of the unsigned {@code long}
383 * value represented by the argument in binary (base 2).
384 * @see #parseUnsignedLong(String, int)
385 * @see #toUnsignedString(long, int)
386 * @since 1.0.2
387 */
388 public static String toBinaryString(long i) {
389 return toUnsignedString0(i, 1);
390 }
391
392 /**
393 * Format a long (treated as unsigned) into a String.
394 * @param val the value to format
395 * @param shift the log2 of the base to format in (4 for hex, 3 for octal, 1 for binary)
396 */
397 static String toUnsignedString0(long val, int shift) {
398 // assert shift > 0 && shift <=5 : "Illegal shift value";
399 int mag = Long.SIZE - Long.numberOfLeadingZeros(val);
400 int chars = Math.max(((mag + (shift - 1)) / shift), 1);
401 if (COMPACT_STRINGS) {
402 byte[] buf = new byte[chars];
403 formatUnsignedLong0(val, shift, buf, 0, chars);
404 return new String(buf, LATIN1);
405 } else {
406 byte[] buf = new byte[chars * 2];
407 formatUnsignedLong0UTF16(val, shift, buf, 0, chars);
408 return new String(buf, UTF16);
409 }
410 }
411
412 /**
413 * Format a long (treated as unsigned) into a byte buffer (LATIN1 version). If
414 * {@code len} exceeds the formatted ASCII representation of {@code val},
415 * {@code buf} will be padded with leading zeroes.
416 *
417 * @param val the unsigned long to format
418 * @param shift the log2 of the base to format in (4 for hex, 3 for octal, 1 for binary)
419 * @param buf the byte buffer to write to
420 * @param offset the offset in the destination buffer to start at
421 * @param len the number of characters to write
422 */
423 private static void formatUnsignedLong0(long val, int shift, byte[] buf, int offset, int len) {
424 int charPos = offset + len;
425 int radix = 1 << shift;
426 int mask = radix - 1;
427 do {
428 buf[--charPos] = (byte)Integer.digits[((int) val) & mask];
429 val >>>= shift;
430 } while (charPos > offset);
431 }
432
433 /**
434 * Format a long (treated as unsigned) into a byte buffer (UTF16 version). If
435 * {@code len} exceeds the formatted ASCII representation of {@code val},
436 * {@code buf} will be padded with leading zeroes.
437 *
438 * @param val the unsigned long to format
439 * @param shift the log2 of the base to format in (4 for hex, 3 for octal, 1 for binary)
440 * @param buf the byte buffer to write to
441 * @param offset the offset in the destination buffer to start at
442 * @param len the number of characters to write
443 */
444 private static void formatUnsignedLong0UTF16(long val, int shift, byte[] buf, int offset, int len) {
445 int charPos = offset + len;
446 int radix = 1 << shift;
447 int mask = radix - 1;
448 do {
449 StringUTF16.putChar(buf, --charPos, Integer.digits[((int) val) & mask]);
450 val >>>= shift;
451 } while (charPos > offset);
452 }
453
454 /**
455 * Returns a {@code String} object representing the specified
456 * {@code long}. The argument is converted to signed decimal
457 * representation and returned as a string, exactly as if the
458 * argument and the radix 10 were given as arguments to the {@link
459 * #toString(long, int)} method.
460 *
461 * @param i a {@code long} to be converted.
462 * @return a string representation of the argument in base 10.
463 */
464 public static String toString(long i) {
465 int size = DecimalDigits.stringSize(i);
466 if (COMPACT_STRINGS) {
467 byte[] buf = new byte[size];
468 StringLatin1.getChars(i, size, buf);
469 return new String(buf, LATIN1);
470 } else {
471 byte[] buf = new byte[size * 2];
472 StringUTF16.getChars(i, size, buf);
473 return new String(buf, UTF16);
474 }
475 }
476
477 /**
478 * Returns a string representation of the argument as an unsigned
479 * decimal value.
480 *
481 * The argument is converted to unsigned decimal representation
482 * and returned as a string exactly as if the argument and radix
483 * 10 were given as arguments to the {@link #toUnsignedString(long,
484 * int)} method.
485 *
486 * @param i an integer to be converted to an unsigned string.
487 * @return an unsigned string representation of the argument.
488 * @see #toUnsignedString(long, int)
489 * @since 1.8
490 */
491 public static String toUnsignedString(long i) {
492 return toUnsignedString(i, 10);
493 }
494
495 /**
496 * Parses the string argument as a signed {@code long} in the
497 * radix specified by the second argument. The characters in the
498 * string must all be digits of the specified radix (as determined
499 * by whether {@link java.lang.Character#digit(char, int)} returns
500 * a nonnegative value), except that the first character may be an
501 * ASCII minus sign {@code '-'} ({@code '\u005Cu002D'}) to
502 * indicate a negative value or an ASCII plus sign {@code '+'}
503 * ({@code '\u005Cu002B'}) to indicate a positive value. The
504 * resulting {@code long} value is returned.
505 *
506 * <p>Note that neither the character {@code L}
507 * ({@code '\u005Cu004C'}) nor {@code l}
508 * ({@code '\u005Cu006C'}) is permitted to appear at the end
509 * of the string as a type indicator, as would be permitted in
510 * Java programming language source code - except that either
511 * {@code L} or {@code l} may appear as a digit for a
512 * radix greater than or equal to 22.
513 *
514 * <p>An exception of type {@code NumberFormatException} is
515 * thrown if any of the following situations occurs:
516 * <ul>
517 *
518 * <li>The first argument is {@code null} or is a string of
519 * length zero.
520 *
521 * <li>The {@code radix} is either smaller than {@link
522 * java.lang.Character#MIN_RADIX} or larger than {@link
523 * java.lang.Character#MAX_RADIX}.
524 *
525 * <li>Any character of the string is not a digit of the specified
526 * radix, except that the first character may be a minus sign
527 * {@code '-'} ({@code '\u005Cu002d'}) or plus sign {@code
528 * '+'} ({@code '\u005Cu002B'}) provided that the string is
529 * longer than length 1.
530 *
531 * <li>The value represented by the string is not a value of type
532 * {@code long}.
533 * </ul>
534 *
535 * <p>Examples:
536 * <blockquote><pre>
537 * parseLong("0", 10) returns 0L
538 * parseLong("473", 10) returns 473L
539 * parseLong("+42", 10) returns 42L
540 * parseLong("-0", 10) returns 0L
541 * parseLong("-FF", 16) returns -255L
542 * parseLong("1100110", 2) returns 102L
543 * parseLong("99", 8) throws a NumberFormatException
544 * parseLong("Hazelnut", 10) throws a NumberFormatException
545 * parseLong("Hazelnut", 36) returns 1356099454469L
546 * </pre></blockquote>
547 *
548 * @param s the {@code String} containing the
549 * {@code long} representation to be parsed.
550 * @param radix the radix to be used while parsing {@code s}.
551 * @return the {@code long} represented by the string argument in
552 * the specified radix.
553 * @throws NumberFormatException if the string does not contain a
554 * parsable {@code long}.
555 */
556 public static long parseLong(String s, int radix)
557 throws NumberFormatException {
558 if (s == null) {
559 throw new NumberFormatException("Cannot parse null string");
560 }
561
562 if (radix < Character.MIN_RADIX) {
563 throw new NumberFormatException(String.format(
564 "radix %s less than Character.MIN_RADIX", radix));
565 }
566
567 if (radix > Character.MAX_RADIX) {
568 throw new NumberFormatException(String.format(
569 "radix %s greater than Character.MAX_RADIX", radix));
570 }
571
572 int len = s.length();
573 if (len == 0) {
574 throw NumberFormatException.forInputString("", radix);
575 }
576 int digit = ~0xFF;
577 int i = 0;
578 char firstChar = s.charAt(i++);
579 if (firstChar != '-' && firstChar != '+') {
580 digit = digit(firstChar, radix);
581 }
582 if (digit >= 0 || digit == ~0xFF && len > 1) {
583 long limit = firstChar != '-' ? MIN_VALUE + 1 : MIN_VALUE;
584 long multmin = limit / radix;
585 long result = -(digit & 0xFF);
586 boolean inRange = true;
587 /* Accumulating negatively avoids surprises near MAX_VALUE */
588 while (i < len && (digit = digit(s.charAt(i++), radix)) >= 0
589 && (inRange = result > multmin
590 || result == multmin && digit <= (int) (radix * multmin - limit))) {
591 result = radix * result - digit;
592 }
593 if (inRange && i == len && digit >= 0) {
594 return firstChar != '-' ? -result : result;
595 }
596 }
597 throw NumberFormatException.forInputString(s, radix);
598 }
599
600 /**
601 * Parses the {@link CharSequence} argument as a signed {@code long} in
602 * the specified {@code radix}, beginning at the specified
603 * {@code beginIndex} and extending to {@code endIndex - 1}.
604 *
605 * <p>The method does not take steps to guard against the
606 * {@code CharSequence} being mutated while parsing.
607 *
608 * @param s the {@code CharSequence} containing the {@code long}
609 * representation to be parsed
610 * @param beginIndex the beginning index, inclusive.
611 * @param endIndex the ending index, exclusive.
612 * @param radix the radix to be used while parsing {@code s}.
613 * @return the signed {@code long} represented by the subsequence in
614 * the specified radix.
615 * @throws NullPointerException if {@code s} is null.
616 * @throws IndexOutOfBoundsException if {@code beginIndex} is
617 * negative, or if {@code beginIndex} is greater than
618 * {@code endIndex} or if {@code endIndex} is greater than
619 * {@code s.length()}.
620 * @throws NumberFormatException if the {@code CharSequence} does not
621 * contain a parsable {@code long} in the specified
622 * {@code radix}, or if {@code radix} is either smaller than
623 * {@link java.lang.Character#MIN_RADIX} or larger than
624 * {@link java.lang.Character#MAX_RADIX}.
625 * @since 9
626 */
627 public static long parseLong(CharSequence s, int beginIndex, int endIndex, int radix)
628 throws NumberFormatException {
629 Objects.requireNonNull(s);
630 Objects.checkFromToIndex(beginIndex, endIndex, s.length());
631
632 if (radix < Character.MIN_RADIX) {
633 throw new NumberFormatException(String.format(
634 "radix %s less than Character.MIN_RADIX", radix));
635 }
636
637 if (radix > Character.MAX_RADIX) {
638 throw new NumberFormatException(String.format(
639 "radix %s greater than Character.MAX_RADIX", radix));
640 }
641
642 /*
643 * While s can be concurrently modified, it is ensured that each
644 * of its characters is read at most once, from lower to higher indices.
645 * This is obtained by reading them using the pattern s.charAt(i++),
646 * and by not updating i anywhere else.
647 */
648 if (beginIndex == endIndex) {
649 throw NumberFormatException.forInputString("", radix);
650 }
651 int digit = ~0xFF; // ~0xFF means firstChar char is sign
652 int i = beginIndex;
653 char firstChar = s.charAt(i++);
654 if (firstChar != '-' && firstChar != '+') {
655 digit = digit(firstChar, radix);
656 }
657 if (digit >= 0 || digit == ~0xFF && endIndex - beginIndex > 1) {
658 long limit = firstChar != '-' ? MIN_VALUE + 1 : MIN_VALUE;
659 long multmin = limit / radix;
660 long result = -(digit & 0xFF);
661 boolean inRange = true;
662 /* Accumulating negatively avoids surprises near MAX_VALUE */
663 while (i < endIndex && (digit = digit(s.charAt(i++), radix)) >= 0
664 && (inRange = result > multmin
665 || result == multmin && digit <= (int) (radix * multmin - limit))) {
666 result = radix * result - digit;
667 }
668 if (inRange && i == endIndex && digit >= 0) {
669 return firstChar != '-' ? -result : result;
670 }
671 }
672 throw NumberFormatException.forCharSequence(s, beginIndex,
673 endIndex, i - (digit < -1 ? 0 : 1));
674 }
675
676 /**
677 * Parses the string argument as a signed decimal {@code long}.
678 * The characters in the string must all be decimal digits, except
679 * that the first character may be an ASCII minus sign {@code '-'}
680 * ({@code \u005Cu002D'}) to indicate a negative value or an
681 * ASCII plus sign {@code '+'} ({@code '\u005Cu002B'}) to
682 * indicate a positive value. The resulting {@code long} value is
683 * returned, exactly as if the argument and the radix {@code 10}
684 * were given as arguments to the {@link
685 * #parseLong(java.lang.String, int)} method.
686 *
687 * <p>Note that neither the character {@code L}
688 * ({@code '\u005Cu004C'}) nor {@code l}
689 * ({@code '\u005Cu006C'}) is permitted to appear at the end
690 * of the string as a type indicator, as would be permitted in
691 * Java programming language source code.
692 *
693 * @param s a {@code String} containing the {@code long}
694 * representation to be parsed
695 * @return the {@code long} represented by the argument in
696 * decimal.
697 * @throws NumberFormatException if the string does not contain a
698 * parsable {@code long}.
699 */
700 public static long parseLong(String s) throws NumberFormatException {
701 return parseLong(s, 10);
702 }
703
704 /**
705 * Parses the string argument as an unsigned {@code long} in the
706 * radix specified by the second argument. An unsigned integer
707 * maps the values usually associated with negative numbers to
708 * positive numbers larger than {@code MAX_VALUE}.
709 *
710 * The characters in the string must all be digits of the
711 * specified radix (as determined by whether {@link
712 * java.lang.Character#digit(char, int)} returns a nonnegative
713 * value), except that the first character may be an ASCII plus
714 * sign {@code '+'} ({@code '\u005Cu002B'}). The resulting
715 * integer value is returned.
716 *
717 * <p>An exception of type {@code NumberFormatException} is
718 * thrown if any of the following situations occurs:
719 * <ul>
720 * <li>The first argument is {@code null} or is a string of
721 * length zero.
722 *
723 * <li>The radix is either smaller than
724 * {@link java.lang.Character#MIN_RADIX} or
725 * larger than {@link java.lang.Character#MAX_RADIX}.
726 *
727 * <li>Any character of the string is not a digit of the specified
728 * radix, except that the first character may be a plus sign
729 * {@code '+'} ({@code '\u005Cu002B'}) provided that the
730 * string is longer than length 1.
731 *
732 * <li>The value represented by the string is larger than the
733 * largest unsigned {@code long}, 2<sup>64</sup>-1.
734 *
735 * </ul>
736 *
737 *
738 * @param s the {@code String} containing the unsigned integer
739 * representation to be parsed
740 * @param radix the radix to be used while parsing {@code s}.
741 * @return the unsigned {@code long} represented by the string
742 * argument in the specified radix.
743 * @throws NumberFormatException if the {@code String}
744 * does not contain a parsable {@code long}.
745 * @since 1.8
746 */
747 public static long parseUnsignedLong(String s, int radix)
748 throws NumberFormatException {
749 if (s == null) {
750 throw new NumberFormatException("Cannot parse null string");
751 }
752
753 if (radix < Character.MIN_RADIX) {
754 throw new NumberFormatException(String.format(
755 "radix %s less than Character.MIN_RADIX", radix));
756 }
757
758 if (radix > Character.MAX_RADIX) {
759 throw new NumberFormatException(String.format(
760 "radix %s greater than Character.MAX_RADIX", radix));
761 }
762
763 int len = s.length();
764 if (len == 0) {
765 throw NumberFormatException.forInputString(s, radix);
766 }
767 int i = 0;
768 char firstChar = s.charAt(i++);
769 if (firstChar == '-') {
770 throw new NumberFormatException(String.format(
771 "Illegal leading minus sign on unsigned string %s.", s));
772 }
773 int digit = ~0xFF;
774 if (firstChar != '+') {
775 digit = digit(firstChar, radix);
776 }
777 if (digit >= 0 || digit == ~0xFF && len > 1) {
778 long multmax = divideUnsigned(-1L, radix); // -1L is max unsigned long
779 long result = digit & 0xFF;
780 boolean inRange = true;
781 while (i < len && (digit = digit(s.charAt(i++), radix)) >= 0
782 && (inRange = compareUnsigned(result, multmax) < 0
783 || result == multmax && digit < (int) (-radix * multmax))) {
784 result = radix * result + digit;
785 }
786 if (inRange && i == len && digit >= 0) {
787 return result;
788 }
789 }
790 if (digit < 0) {
791 throw NumberFormatException.forInputString(s, radix);
792 }
793 throw new NumberFormatException(String.format(
794 "String value %s exceeds range of unsigned long.", s));
795 }
796
797 /**
798 * Parses the {@link CharSequence} argument as an unsigned {@code long} in
799 * the specified {@code radix}, beginning at the specified
800 * {@code beginIndex} and extending to {@code endIndex - 1}.
801 *
802 * <p>The method does not take steps to guard against the
803 * {@code CharSequence} being mutated while parsing.
804 *
805 * @param s the {@code CharSequence} containing the unsigned
806 * {@code long} representation to be parsed
807 * @param beginIndex the beginning index, inclusive.
808 * @param endIndex the ending index, exclusive.
809 * @param radix the radix to be used while parsing {@code s}.
810 * @return the unsigned {@code long} represented by the subsequence in
811 * the specified radix.
812 * @throws NullPointerException if {@code s} is null.
813 * @throws IndexOutOfBoundsException if {@code beginIndex} is
814 * negative, or if {@code beginIndex} is greater than
815 * {@code endIndex} or if {@code endIndex} is greater than
816 * {@code s.length()}.
817 * @throws NumberFormatException if the {@code CharSequence} does not
818 * contain a parsable unsigned {@code long} in the specified
819 * {@code radix}, or if {@code radix} is either smaller than
820 * {@link java.lang.Character#MIN_RADIX} or larger than
821 * {@link java.lang.Character#MAX_RADIX}.
822 * @since 9
823 */
824 public static long parseUnsignedLong(CharSequence s, int beginIndex, int endIndex, int radix)
825 throws NumberFormatException {
826 Objects.requireNonNull(s);
827 Objects.checkFromToIndex(beginIndex, endIndex, s.length());
828
829 if (radix < Character.MIN_RADIX) {
830 throw new NumberFormatException(String.format(
831 "radix %s less than Character.MIN_RADIX", radix));
832 }
833
834 if (radix > Character.MAX_RADIX) {
835 throw new NumberFormatException(String.format(
836 "radix %s greater than Character.MAX_RADIX", radix));
837 }
838
839 /*
840 * While s can be concurrently modified, it is ensured that each
841 * of its characters is read at most once, from lower to higher indices.
842 * This is obtained by reading them using the pattern s.charAt(i++),
843 * and by not updating i anywhere else.
844 */
845 if (beginIndex == endIndex) {
846 throw NumberFormatException.forInputString("", radix);
847 }
848 int i = beginIndex;
849 char firstChar = s.charAt(i++);
850 if (firstChar == '-') {
851 throw new NumberFormatException(
852 "Illegal leading minus sign on unsigned string " + s + ".");
853 }
854 int digit = ~0xFF;
855 if (firstChar != '+') {
856 digit = digit(firstChar, radix);
857 }
858 if (digit >= 0 || digit == ~0xFF && endIndex - beginIndex > 1) {
859 long multmax = divideUnsigned(-1L, radix); // -1L is max unsigned long
860 long result = digit & 0xFF;
861 boolean inRange = true;
862 while (i < endIndex && (digit = digit(s.charAt(i++), radix)) >= 0
863 && (inRange = compareUnsigned(result, multmax) < 0
864 || result == multmax && digit < (int) (-radix * multmax))) {
865 result = radix * result + digit;
866 }
867 if (inRange && i == endIndex && digit >= 0) {
868 return result;
869 }
870 }
871 if (digit < 0) {
872 throw NumberFormatException.forCharSequence(s, beginIndex,
873 endIndex, i - (digit < -1 ? 0 : 1));
874 }
875 throw new NumberFormatException(String.format(
876 "String value %s exceeds range of unsigned long.", s));
877 }
878
879 /**
880 * Parses the string argument as an unsigned decimal {@code long}. The
881 * characters in the string must all be decimal digits, except
882 * that the first character may be an ASCII plus sign {@code
883 * '+'} ({@code '\u005Cu002B'}). The resulting integer value
884 * is returned, exactly as if the argument and the radix 10 were
885 * given as arguments to the {@link
886 * #parseUnsignedLong(java.lang.String, int)} method.
887 *
888 * @param s a {@code String} containing the unsigned {@code long}
889 * representation to be parsed
890 * @return the unsigned {@code long} value represented by the decimal string argument
891 * @throws NumberFormatException if the string does not contain a
892 * parsable unsigned integer.
893 * @since 1.8
894 */
895 public static long parseUnsignedLong(String s) throws NumberFormatException {
896 return parseUnsignedLong(s, 10);
897 }
898
899 /**
900 * Returns a {@code Long} object holding the value
901 * extracted from the specified {@code String} when parsed
902 * with the radix given by the second argument. The first
903 * argument is interpreted as representing a signed
904 * {@code long} in the radix specified by the second
905 * argument, exactly as if the arguments were given to the {@link
906 * #parseLong(java.lang.String, int)} method. The result is a
907 * {@code Long} object that represents the {@code long}
908 * value specified by the string.
909 *
910 * <p>In other words, this method returns a {@code Long} object equal
911 * to the value of:
912 *
913 * <blockquote>
914 * {@code Long.valueOf(Long.parseLong(s, radix))}
915 * </blockquote>
916 *
917 * @param s the string to be parsed
918 * @param radix the radix to be used in interpreting {@code s}
919 * @return a {@code Long} object holding the value
920 * represented by the string argument in the specified
921 * radix.
922 * @throws NumberFormatException If the {@code String} does not
923 * contain a parsable {@code long}.
924 */
925 public static Long valueOf(String s, int radix) throws NumberFormatException {
926 return Long.valueOf(parseLong(s, radix));
927 }
928
929 /**
930 * Returns a {@code Long} object holding the value
931 * of the specified {@code String}. The argument is
932 * interpreted as representing a signed decimal {@code long},
933 * exactly as if the argument were given to the {@link
934 * #parseLong(java.lang.String)} method. The result is a
935 * {@code Long} object that represents the integer value
936 * specified by the string.
937 *
938 * <p>In other words, this method returns a {@code Long} object
939 * equal to the value of:
940 *
941 * <blockquote>
942 * {@code Long.valueOf(Long.parseLong(s))}
943 * </blockquote>
944 *
945 * @param s the string to be parsed.
946 * @return a {@code Long} object holding the value
947 * represented by the string argument.
948 * @throws NumberFormatException If the string cannot be parsed
949 * as a {@code long}.
950 */
951 public static Long valueOf(String s) throws NumberFormatException
952 {
953 return Long.valueOf(parseLong(s, 10));
954 }
955
956 private static final class LongCache {
957 private LongCache() {}
958
959 @Stable
960 static final Long[] cache;
961 static Long[] archivedCache;
962
963 static {
964 int size = -(-128) + 127 + 1;
965
966 // Load and use the archived cache if it exists
967 CDS.initializeFromArchive(LongCache.class);
968 if (archivedCache == null || archivedCache.length != size) {
969 Long[] c = new Long[size];
970 long value = -128;
971 for(int i = 0; i < size; i++) {
972 c[i] = new Long(value++);
973 }
974 archivedCache = c;
975 }
976 cache = archivedCache;
977 }
978 }
979
980 /**
981 * Returns a {@code Long} instance representing the specified
982 * {@code long} value.
983 * If a new {@code Long} instance is not required, this method
984 * should generally be used in preference to the constructor
985 * {@link #Long(long)}, as this method is likely to yield
986 * significantly better space and time performance by caching
987 * frequently requested values.
988 *
989 * This method will always cache values in the range -128 to 127,
990 * inclusive, and may cache other values outside of this range.
991 *
992 * @param l a long value.
993 * @return a {@code Long} instance representing {@code l}.
994 * @since 1.5
995 */
996 @IntrinsicCandidate
997 @DeserializeConstructor
998 public static Long valueOf(long l) {
999 final int offset = 128;
1000 if (l >= -128 && l <= 127) { // will cache
1001 return LongCache.cache[(int)l + offset];
1002 }
1003 return new Long(l);
1004 }
1005
1006 /**
1007 * Decodes a {@code String} into a {@code Long}.
1008 * Accepts decimal, hexadecimal, and octal numbers given by the
1009 * following grammar:
1010 *
1011 * <blockquote>
1012 * <dl>
1013 * <dt><i>DecodableString:</i>
1014 * <dd><i>Sign<sub>opt</sub> DecimalNumeral</i>
1015 * <dd><i>Sign<sub>opt</sub></i> {@code 0x} <i>HexDigits</i>
1016 * <dd><i>Sign<sub>opt</sub></i> {@code 0X} <i>HexDigits</i>
1017 * <dd><i>Sign<sub>opt</sub></i> {@code #} <i>HexDigits</i>
1018 * <dd><i>Sign<sub>opt</sub></i> {@code 0} <i>OctalDigits</i>
1019 *
1020 * <dt><i>Sign:</i>
1021 * <dd>{@code -}
1022 * <dd>{@code +}
1023 * </dl>
1024 * </blockquote>
1025 *
1026 * <i>DecimalNumeral</i>, <i>HexDigits</i>, and <i>OctalDigits</i>
1027 * are as defined in section {@jls 3.10.1} of
1028 * <cite>The Java Language Specification</cite>,
1029 * except that underscores are not accepted between digits.
1030 *
1031 * <p>The sequence of characters following an optional
1032 * sign and/or radix specifier ("{@code 0x}", "{@code 0X}",
1033 * "{@code #}", or leading zero) is parsed as by the {@code
1034 * Long.parseLong} method with the indicated radix (10, 16, or 8).
1035 * This sequence of characters must represent a positive value or
1036 * a {@link NumberFormatException} will be thrown. The result is
1037 * negated if first character of the specified {@code String} is
1038 * the minus sign. No whitespace characters are permitted in the
1039 * {@code String}.
1040 *
1041 * @param nm the {@code String} to decode.
1042 * @return a {@code Long} object holding the {@code long}
1043 * value represented by {@code nm}
1044 * @throws NumberFormatException if the {@code String} does not
1045 * contain a parsable {@code long}.
1046 * @see java.lang.Long#parseLong(String, int)
1047 * @since 1.2
1048 */
1049 public static Long decode(String nm) throws NumberFormatException {
1050 int radix = 10;
1051 int index = 0;
1052 boolean negative = false;
1053 long result;
1054
1055 if (nm.isEmpty())
1056 throw new NumberFormatException("Zero length string");
1057 char firstChar = nm.charAt(0);
1058 // Handle sign, if present
1059 if (firstChar == '-') {
1060 negative = true;
1061 index++;
1062 } else if (firstChar == '+')
1063 index++;
1064
1065 // Handle radix specifier, if present
1066 if (nm.startsWith("0x", index) || nm.startsWith("0X", index)) {
1067 index += 2;
1068 radix = 16;
1069 }
1070 else if (nm.startsWith("#", index)) {
1071 index ++;
1072 radix = 16;
1073 }
1074 else if (nm.startsWith("0", index) && nm.length() > 1 + index) {
1075 index ++;
1076 radix = 8;
1077 }
1078
1079 if (nm.startsWith("-", index) || nm.startsWith("+", index))
1080 throw new NumberFormatException("Sign character in wrong position");
1081
1082 try {
1083 result = parseLong(nm, index, nm.length(), radix);
1084 result = negative ? -result : result;
1085 } catch (NumberFormatException e) {
1086 // If number is Long.MIN_VALUE, we'll end up here. The next line
1087 // handles this case, and causes any genuine format error to be
1088 // rethrown.
1089 String constant = negative ? ("-" + nm.substring(index))
1090 : nm.substring(index);
1091 result = parseLong(constant, radix);
1092 }
1093 return result;
1094 }
1095
1096 /**
1097 * The value of the {@code Long}.
1098 *
1099 * @serial
1100 */
1101 private final long value;
1102
1103 /**
1104 * Constructs a newly allocated {@code Long} object that
1105 * represents the specified {@code long} argument.
1106 *
1107 * @param value the value to be represented by the
1108 * {@code Long} object.
1109 *
1110 * @deprecated
1111 * It is rarely appropriate to use this constructor. The static factory
1112 * {@link #valueOf(long)} is generally a better choice, as it is
1113 * likely to yield significantly better space and time performance.
1114 */
1115 @Deprecated(since="9", forRemoval = true)
1116 public Long(long value) {
1117 this.value = value;
1118 }
1119
1120 /**
1121 * Constructs a newly allocated {@code Long} object that
1122 * represents the {@code long} value indicated by the
1123 * {@code String} parameter. The string is converted to a
1124 * {@code long} value in exactly the manner used by the
1125 * {@code parseLong} method for radix 10.
1126 *
1127 * @param s the {@code String} to be converted to a
1128 * {@code Long}.
1129 * @throws NumberFormatException if the {@code String} does not
1130 * contain a parsable {@code long}.
1131 *
1132 * @deprecated
1133 * It is rarely appropriate to use this constructor.
1134 * Use {@link #parseLong(String)} to convert a string to a
1135 * {@code long} primitive, or use {@link #valueOf(String)}
1136 * to convert a string to a {@code Long} object.
1137 */
1138 @Deprecated(since="9", forRemoval = true)
1139 public Long(String s) throws NumberFormatException {
1140 this.value = parseLong(s, 10);
1141 }
1142
1143 /**
1144 * Returns the value of this {@code Long} as a {@code byte} after
1145 * a narrowing primitive conversion.
1146 * @jls 5.1.3 Narrowing Primitive Conversion
1147 */
1148 public byte byteValue() {
1149 return (byte)value;
1150 }
1151
1152 /**
1153 * Returns the value of this {@code Long} as a {@code short} after
1154 * a narrowing primitive conversion.
1155 * @jls 5.1.3 Narrowing Primitive Conversion
1156 */
1157 public short shortValue() {
1158 return (short)value;
1159 }
1160
1161 /**
1162 * Returns the value of this {@code Long} as an {@code int} after
1163 * a narrowing primitive conversion.
1164 * @jls 5.1.3 Narrowing Primitive Conversion
1165 */
1166 public int intValue() {
1167 return (int)value;
1168 }
1169
1170 /**
1171 * Returns the value of this {@code Long} as a
1172 * {@code long} value.
1173 */
1174 @IntrinsicCandidate
1175 public long longValue() {
1176 return value;
1177 }
1178
1179 /**
1180 * Returns the value of this {@code Long} as a {@code float} after
1181 * a widening primitive conversion.
1182 * @jls 5.1.2 Widening Primitive Conversion
1183 */
1184 public float floatValue() {
1185 return (float)value;
1186 }
1187
1188 /**
1189 * Returns the value of this {@code Long} as a {@code double}
1190 * after a widening primitive conversion.
1191 * @jls 5.1.2 Widening Primitive Conversion
1192 */
1193 public double doubleValue() {
1194 return (double)value;
1195 }
1196
1197 /**
1198 * Returns a {@code String} object representing this
1199 * {@code Long}'s value. The value is converted to signed
1200 * decimal representation and returned as a string, exactly as if
1201 * the {@code long} value were given as an argument to the
1202 * {@link java.lang.Long#toString(long)} method.
1203 *
1204 * @return a string representation of the value of this object in
1205 * base 10.
1206 */
1207 public String toString() {
1208 return toString(value);
1209 }
1210
1211 /**
1212 * Returns a hash code for this {@code Long}. The result is
1213 * the exclusive OR of the two halves of the primitive
1214 * {@code long} value held by this {@code Long}
1215 * object. That is, the hashcode is the value of the expression:
1216 *
1217 * <blockquote>
1218 * {@code (int)(this.longValue()^(this.longValue()>>>32))}
1219 * </blockquote>
1220 *
1221 * @return a hash code value for this object.
1222 */
1223 @Override
1224 public int hashCode() {
1225 return Long.hashCode(value);
1226 }
1227
1228 /**
1229 * Returns a hash code for a {@code long} value; compatible with
1230 * {@code Long.hashCode()}.
1231 *
1232 * @param value the value to hash
1233 * @return a hash code value for a {@code long} value.
1234 * @since 1.8
1235 */
1236 public static int hashCode(long value) {
1237 return (int)(value ^ (value >>> 32));
1238 }
1239
1240 /**
1241 * Compares this object to the specified object. The result is
1242 * {@code true} if and only if the argument is not
1243 * {@code null} and is a {@code Long} object that
1244 * contains the same {@code long} value as this object.
1245 *
1246 * @param obj the object to compare with.
1247 * @return {@code true} if the objects are the same;
1248 * {@code false} otherwise.
1249 */
1250 public boolean equals(Object obj) {
1251 if (obj instanceof Long) {
1252 return value == ((Long)obj).longValue();
1253 }
1254 return false;
1255 }
1256
1257 /**
1258 * Determines the {@code long} value of the system property
1259 * with the specified name.
1260 *
1261 * <p>The first argument is treated as the name of a system
1262 * property. System properties are accessible through the {@link
1263 * java.lang.System#getProperty(java.lang.String)} method. The
1264 * string value of this property is then interpreted as a {@code
1265 * long} value using the grammar supported by {@link Long#decode decode}
1266 * and a {@code Long} object representing this value is returned.
1267 *
1268 * <p>If there is no property with the specified name, if the
1269 * specified name is empty or {@code null}, or if the property
1270 * does not have the correct numeric format, then {@code null} is
1271 * returned.
1272 *
1273 * <p>In other words, this method returns a {@code Long} object
1274 * equal to the value of:
1275 *
1276 * <blockquote>
1277 * {@code getLong(nm, null)}
1278 * </blockquote>
1279 *
1280 * @param nm property name.
1281 * @return the {@code Long} value of the property.
1282 * @throws SecurityException for the same reasons as
1283 * {@link System#getProperty(String) System.getProperty}
1284 * @see java.lang.System#getProperty(java.lang.String)
1285 * @see java.lang.System#getProperty(java.lang.String, java.lang.String)
1286 */
1287 public static Long getLong(String nm) {
1288 return getLong(nm, null);
1289 }
1290
1291 /**
1292 * Determines the {@code long} value of the system property
1293 * with the specified name.
1294 *
1295 * <p>The first argument is treated as the name of a system
1296 * property. System properties are accessible through the {@link
1297 * java.lang.System#getProperty(java.lang.String)} method. The
1298 * string value of this property is then interpreted as a {@code
1299 * long} value using the grammar supported by {@link Long#decode decode}
1300 * and a {@code Long} object representing this value is returned.
1301 *
1302 * <p>The second argument is the default value. A {@code Long} object
1303 * that represents the value of the second argument is returned if there
1304 * is no property of the specified name, if the property does not have
1305 * the correct numeric format, or if the specified name is empty or null.
1306 *
1307 * <p>In other words, this method returns a {@code Long} object equal
1308 * to the value of:
1309 *
1310 * <blockquote>
1311 * {@code getLong(nm, Long.valueOf(val))}
1312 * </blockquote>
1313 *
1314 * but in practice it may be implemented in a manner such as:
1315 *
1316 * <blockquote><pre>
1317 * Long result = getLong(nm, null);
1318 * return (result == null) ? Long.valueOf(val) : result;
1319 * </pre></blockquote>
1320 *
1321 * to avoid the unnecessary allocation of a {@code Long} object when
1322 * the default value is not needed.
1323 *
1324 * @param nm property name.
1325 * @param val default value.
1326 * @return the {@code Long} value of the property.
1327 * @throws SecurityException for the same reasons as
1328 * {@link System#getProperty(String) System.getProperty}
1329 * @see java.lang.System#getProperty(java.lang.String)
1330 * @see java.lang.System#getProperty(java.lang.String, java.lang.String)
1331 */
1332 public static Long getLong(String nm, long val) {
1333 Long result = Long.getLong(nm, null);
1334 return (result == null) ? Long.valueOf(val) : result;
1335 }
1336
1337 /**
1338 * Returns the {@code long} value of the system property with
1339 * the specified name. The first argument is treated as the name
1340 * of a system property. System properties are accessible through
1341 * the {@link java.lang.System#getProperty(java.lang.String)}
1342 * method. The string value of this property is then interpreted
1343 * as a {@code long} value, as per the
1344 * {@link Long#decode decode} method, and a {@code Long} object
1345 * representing this value is returned; in summary:
1346 *
1347 * <ul>
1348 * <li>If the property value begins with the two ASCII characters
1349 * {@code 0x} or the ASCII character {@code #}, not followed by
1350 * a minus sign, then the rest of it is parsed as a hexadecimal integer
1351 * exactly as for the method {@link #valueOf(java.lang.String, int)}
1352 * with radix 16.
1353 * <li>If the property value begins with the ASCII character
1354 * {@code 0} followed by another character, it is parsed as
1355 * an octal integer exactly as by the method {@link
1356 * #valueOf(java.lang.String, int)} with radix 8.
1357 * <li>Otherwise the property value is parsed as a decimal
1358 * integer exactly as by the method
1359 * {@link #valueOf(java.lang.String, int)} with radix 10.
1360 * </ul>
1361 *
1362 * <p>Note that, in every case, neither {@code L}
1363 * ({@code '\u005Cu004C'}) nor {@code l}
1364 * ({@code '\u005Cu006C'}) is permitted to appear at the end
1365 * of the property value as a type indicator, as would be
1366 * permitted in Java programming language source code.
1367 *
1368 * <p>The second argument is the default value. The default value is
1369 * returned if there is no property of the specified name, if the
1370 * property does not have the correct numeric format, or if the
1371 * specified name is empty or {@code null}.
1372 *
1373 * @param nm property name.
1374 * @param val default value.
1375 * @return the {@code Long} value of the property.
1376 * @throws SecurityException for the same reasons as
1377 * {@link System#getProperty(String) System.getProperty}
1378 * @see System#getProperty(java.lang.String)
1379 * @see System#getProperty(java.lang.String, java.lang.String)
1380 */
1381 public static Long getLong(String nm, Long val) {
1382 String v = null;
1383 try {
1384 v = System.getProperty(nm);
1385 } catch (IllegalArgumentException | NullPointerException e) {
1386 }
1387 if (v != null) {
1388 try {
1389 return Long.decode(v);
1390 } catch (NumberFormatException e) {
1391 }
1392 }
1393 return val;
1394 }
1395
1396 /**
1397 * Compares two {@code Long} objects numerically.
1398 *
1399 * @param anotherLong the {@code Long} to be compared.
1400 * @return the value {@code 0} if this {@code Long} is
1401 * equal to the argument {@code Long}; a value less than
1402 * {@code 0} if this {@code Long} is numerically less
1403 * than the argument {@code Long}; and a value greater
1404 * than {@code 0} if this {@code Long} is numerically
1405 * greater than the argument {@code Long} (signed
1406 * comparison).
1407 * @since 1.2
1408 */
1409 public int compareTo(Long anotherLong) {
1410 return compare(this.value, anotherLong.value);
1411 }
1412
1413 /**
1414 * Compares two {@code long} values numerically.
1415 * The value returned is identical to what would be returned by:
1416 * <pre>
1417 * Long.valueOf(x).compareTo(Long.valueOf(y))
1418 * </pre>
1419 *
1420 * @param x the first {@code long} to compare
1421 * @param y the second {@code long} to compare
1422 * @return the value {@code 0} if {@code x == y};
1423 * a value less than {@code 0} if {@code x < y}; and
1424 * a value greater than {@code 0} if {@code x > y}
1425 * @since 1.7
1426 */
1427 public static int compare(long x, long y) {
1428 return (x < y) ? -1 : ((x == y) ? 0 : 1);
1429 }
1430
1431 /**
1432 * Compares two {@code long} values numerically treating the values
1433 * as unsigned.
1434 *
1435 * @param x the first {@code long} to compare
1436 * @param y the second {@code long} to compare
1437 * @return the value {@code 0} if {@code x == y}; a value less
1438 * than {@code 0} if {@code x < y} as unsigned values; and
1439 * a value greater than {@code 0} if {@code x > y} as
1440 * unsigned values
1441 * @since 1.8
1442 */
1443 @IntrinsicCandidate
1444 public static int compareUnsigned(long x, long y) {
1445 return compare(x + MIN_VALUE, y + MIN_VALUE);
1446 }
1447
1448
1449 /**
1450 * Returns the unsigned quotient of dividing the first argument by
1451 * the second where each argument and the result is interpreted as
1452 * an unsigned value.
1453 *
1454 * <p>Note that in two's complement arithmetic, the three other
1455 * basic arithmetic operations of add, subtract, and multiply are
1456 * bit-wise identical if the two operands are regarded as both
1457 * being signed or both being unsigned. Therefore separate {@code
1458 * addUnsigned}, etc. methods are not provided.
1459 *
1460 * @param dividend the value to be divided
1461 * @param divisor the value doing the dividing
1462 * @return the unsigned quotient of the first argument divided by
1463 * the second argument
1464 * @see #remainderUnsigned
1465 * @since 1.8
1466 */
1467 @IntrinsicCandidate
1468 public static long divideUnsigned(long dividend, long divisor) {
1469 /* See Hacker's Delight (2nd ed), section 9.3 */
1470 if (divisor >= 0) {
1471 final long q = (dividend >>> 1) / divisor << 1;
1472 final long r = dividend - q * divisor;
1473 return q + ((r | ~(r - divisor)) >>> (Long.SIZE - 1));
1474 }
1475 return (dividend & ~(dividend - divisor)) >>> (Long.SIZE - 1);
1476 }
1477
1478 /**
1479 * Returns the unsigned remainder from dividing the first argument
1480 * by the second where each argument and the result is interpreted
1481 * as an unsigned value.
1482 *
1483 * @param dividend the value to be divided
1484 * @param divisor the value doing the dividing
1485 * @return the unsigned remainder of the first argument divided by
1486 * the second argument
1487 * @see #divideUnsigned
1488 * @since 1.8
1489 */
1490 @IntrinsicCandidate
1491 public static long remainderUnsigned(long dividend, long divisor) {
1492 /* See Hacker's Delight (2nd ed), section 9.3 */
1493 if (divisor >= 0) {
1494 final long q = (dividend >>> 1) / divisor << 1;
1495 final long r = dividend - q * divisor;
1496 /*
1497 * Here, 0 <= r < 2 * divisor
1498 * (1) When 0 <= r < divisor, the remainder is simply r.
1499 * (2) Otherwise the remainder is r - divisor.
1500 *
1501 * In case (1), r - divisor < 0. Applying ~ produces a long with
1502 * sign bit 0, so >> produces 0. The returned value is thus r.
1503 *
1504 * In case (2), a similar reasoning shows that >> produces -1,
1505 * so the returned value is r - divisor.
1506 */
1507 return r - ((~(r - divisor) >> (Long.SIZE - 1)) & divisor);
1508 }
1509 /*
1510 * (1) When dividend >= 0, the remainder is dividend.
1511 * (2) Otherwise
1512 * (2.1) When dividend < divisor, the remainder is dividend.
1513 * (2.2) Otherwise the remainder is dividend - divisor
1514 *
1515 * A reasoning similar to the above shows that the returned value
1516 * is as expected.
1517 */
1518 return dividend - (((dividend & ~(dividend - divisor)) >> (Long.SIZE - 1)) & divisor);
1519 }
1520
1521 // Bit Twiddling
1522
1523 /**
1524 * The number of bits used to represent a {@code long} value in two's
1525 * complement binary form.
1526 *
1527 * @since 1.5
1528 */
1529 @Native public static final int SIZE = 64;
1530
1531 /**
1532 * The number of bytes used to represent a {@code long} value in two's
1533 * complement binary form.
1534 *
1535 * @since 1.8
1536 */
1537 public static final int BYTES = SIZE / Byte.SIZE;
1538
1539 /**
1540 * Returns a {@code long} value with at most a single one-bit, in the
1541 * position of the highest-order ("leftmost") one-bit in the specified
1542 * {@code long} value. Returns zero if the specified value has no
1543 * one-bits in its two's complement binary representation, that is, if it
1544 * is equal to zero.
1545 *
1546 * @param i the value whose highest one bit is to be computed
1547 * @return a {@code long} value with a single one-bit, in the position
1548 * of the highest-order one-bit in the specified value, or zero if
1549 * the specified value is itself equal to zero.
1550 * @since 1.5
1551 */
1552 public static long highestOneBit(long i) {
1553 return i & (MIN_VALUE >>> numberOfLeadingZeros(i));
1554 }
1555
1556 /**
1557 * Returns a {@code long} value with at most a single one-bit, in the
1558 * position of the lowest-order ("rightmost") one-bit in the specified
1559 * {@code long} value. Returns zero if the specified value has no
1560 * one-bits in its two's complement binary representation, that is, if it
1561 * is equal to zero.
1562 *
1563 * @param i the value whose lowest one bit is to be computed
1564 * @return a {@code long} value with a single one-bit, in the position
1565 * of the lowest-order one-bit in the specified value, or zero if
1566 * the specified value is itself equal to zero.
1567 * @since 1.5
1568 */
1569 public static long lowestOneBit(long i) {
1570 // HD, Section 2-1
1571 return i & -i;
1572 }
1573
1574 /**
1575 * Returns the number of zero bits preceding the highest-order
1576 * ("leftmost") one-bit in the two's complement binary representation
1577 * of the specified {@code long} value. Returns 64 if the
1578 * specified value has no one-bits in its two's complement representation,
1579 * in other words if it is equal to zero.
1580 *
1581 * <p>Note that this method is closely related to the logarithm base 2.
1582 * For all positive {@code long} values x:
1583 * <ul>
1584 * <li>floor(log<sub>2</sub>(x)) = {@code 63 - numberOfLeadingZeros(x)}
1585 * <li>ceil(log<sub>2</sub>(x)) = {@code 64 - numberOfLeadingZeros(x - 1)}
1586 * </ul>
1587 *
1588 * @param i the value whose number of leading zeros is to be computed
1589 * @return the number of zero bits preceding the highest-order
1590 * ("leftmost") one-bit in the two's complement binary representation
1591 * of the specified {@code long} value, or 64 if the value
1592 * is equal to zero.
1593 * @since 1.5
1594 */
1595 @IntrinsicCandidate
1596 public static int numberOfLeadingZeros(long i) {
1597 int x = (int)(i >>> 32);
1598 return x == 0 ? 32 + Integer.numberOfLeadingZeros((int)i)
1599 : Integer.numberOfLeadingZeros(x);
1600 }
1601
1602 /**
1603 * Returns the number of zero bits following the lowest-order ("rightmost")
1604 * one-bit in the two's complement binary representation of the specified
1605 * {@code long} value. Returns 64 if the specified value has no
1606 * one-bits in its two's complement representation, in other words if it is
1607 * equal to zero.
1608 *
1609 * @param i the value whose number of trailing zeros is to be computed
1610 * @return the number of zero bits following the lowest-order ("rightmost")
1611 * one-bit in the two's complement binary representation of the
1612 * specified {@code long} value, or 64 if the value is equal
1613 * to zero.
1614 * @since 1.5
1615 */
1616 @IntrinsicCandidate
1617 public static int numberOfTrailingZeros(long i) {
1618 int x = (int)i;
1619 return x == 0 ? 32 + Integer.numberOfTrailingZeros((int)(i >>> 32))
1620 : Integer.numberOfTrailingZeros(x);
1621 }
1622
1623 /**
1624 * Returns the number of one-bits in the two's complement binary
1625 * representation of the specified {@code long} value. This function is
1626 * sometimes referred to as the <i>population count</i>.
1627 *
1628 * @param i the value whose bits are to be counted
1629 * @return the number of one-bits in the two's complement binary
1630 * representation of the specified {@code long} value.
1631 * @since 1.5
1632 */
1633 @IntrinsicCandidate
1634 public static int bitCount(long i) {
1635 // HD, Figure 5-2
1636 i = i - ((i >>> 1) & 0x5555555555555555L);
1637 i = (i & 0x3333333333333333L) + ((i >>> 2) & 0x3333333333333333L);
1638 i = (i + (i >>> 4)) & 0x0f0f0f0f0f0f0f0fL;
1639 i = i + (i >>> 8);
1640 i = i + (i >>> 16);
1641 i = i + (i >>> 32);
1642 return (int)i & 0x7f;
1643 }
1644
1645 /**
1646 * Returns the value obtained by rotating the two's complement binary
1647 * representation of the specified {@code long} value left by the
1648 * specified number of bits. (Bits shifted out of the left hand, or
1649 * high-order, side reenter on the right, or low-order.)
1650 *
1651 * <p>Note that left rotation with a negative distance is equivalent to
1652 * right rotation: {@code rotateLeft(val, -distance) == rotateRight(val,
1653 * distance)}. Note also that rotation by any multiple of 64 is a
1654 * no-op, so all but the last six bits of the rotation distance can be
1655 * ignored, even if the distance is negative: {@code rotateLeft(val,
1656 * distance) == rotateLeft(val, distance & 0x3F)}.
1657 *
1658 * @param i the value whose bits are to be rotated left
1659 * @param distance the number of bit positions to rotate left
1660 * @return the value obtained by rotating the two's complement binary
1661 * representation of the specified {@code long} value left by the
1662 * specified number of bits.
1663 * @since 1.5
1664 */
1665 public static long rotateLeft(long i, int distance) {
1666 return (i << distance) | (i >>> -distance);
1667 }
1668
1669 /**
1670 * Returns the value obtained by rotating the two's complement binary
1671 * representation of the specified {@code long} value right by the
1672 * specified number of bits. (Bits shifted out of the right hand, or
1673 * low-order, side reenter on the left, or high-order.)
1674 *
1675 * <p>Note that right rotation with a negative distance is equivalent to
1676 * left rotation: {@code rotateRight(val, -distance) == rotateLeft(val,
1677 * distance)}. Note also that rotation by any multiple of 64 is a
1678 * no-op, so all but the last six bits of the rotation distance can be
1679 * ignored, even if the distance is negative: {@code rotateRight(val,
1680 * distance) == rotateRight(val, distance & 0x3F)}.
1681 *
1682 * @param i the value whose bits are to be rotated right
1683 * @param distance the number of bit positions to rotate right
1684 * @return the value obtained by rotating the two's complement binary
1685 * representation of the specified {@code long} value right by the
1686 * specified number of bits.
1687 * @since 1.5
1688 */
1689 public static long rotateRight(long i, int distance) {
1690 return (i >>> distance) | (i << -distance);
1691 }
1692
1693 /**
1694 * Returns the value obtained by reversing the order of the bits in the
1695 * two's complement binary representation of the specified {@code long}
1696 * value.
1697 *
1698 * @param i the value to be reversed
1699 * @return the value obtained by reversing order of the bits in the
1700 * specified {@code long} value.
1701 * @since 1.5
1702 */
1703 @IntrinsicCandidate
1704 public static long reverse(long i) {
1705 // HD, Figure 7-1
1706 i = (i & 0x5555555555555555L) << 1 | (i >>> 1) & 0x5555555555555555L;
1707 i = (i & 0x3333333333333333L) << 2 | (i >>> 2) & 0x3333333333333333L;
1708 i = (i & 0x0f0f0f0f0f0f0f0fL) << 4 | (i >>> 4) & 0x0f0f0f0f0f0f0f0fL;
1709
1710 return reverseBytes(i);
1711 }
1712
1713 /**
1714 * Returns the value obtained by compressing the bits of the
1715 * specified {@code long} value, {@code i}, in accordance with
1716 * the specified bit mask.
1717 * <p>
1718 * For each one-bit value {@code mb} of the mask, from least
1719 * significant to most significant, the bit value of {@code i} at
1720 * the same bit location as {@code mb} is assigned to the compressed
1721 * value contiguously starting from the least significant bit location.
1722 * All the upper remaining bits of the compressed value are set
1723 * to zero.
1724 *
1725 * @apiNote
1726 * Consider the simple case of compressing the digits of a hexadecimal
1727 * value:
1728 * {@snippet lang="java" :
1729 * // Compressing drink to food
1730 * compress(0xCAFEBABEL, 0xFF00FFF0L) == 0xCABABL
1731 * }
1732 * Starting from the least significant hexadecimal digit at position 0
1733 * from the right, the mask {@code 0xFF00FFF0} selects hexadecimal digits
1734 * at positions 1, 2, 3, 6 and 7 of {@code 0xCAFEBABE}. The selected digits
1735 * occur in the resulting compressed value contiguously from digit position
1736 * 0 in the same order.
1737 * <p>
1738 * The following identities all return {@code true} and are helpful to
1739 * understand the behaviour of {@code compress}:
1740 * {@snippet lang="java" :
1741 * // Returns 1 if the bit at position n is one
1742 * compress(x, 1L << n) == (x >> n & 1)
1743 *
1744 * // Logical shift right
1745 * compress(x, -1L << n) == x >>> n
1746 *
1747 * // Any bits not covered by the mask are ignored
1748 * compress(x, m) == compress(x & m, m)
1749 *
1750 * // Compressing a value by itself
1751 * compress(m, m) == (m == -1 || m == 0) ? m : (1L << bitCount(m)) - 1
1752 *
1753 * // Expanding then compressing with the same mask
1754 * compress(expand(x, m), m) == x & compress(m, m)
1755 * }
1756 * <p>
1757 * The Sheep And Goats (SAG) operation (see Hacker's Delight, Second Edition, section 7.7)
1758 * can be implemented as follows:
1759 * {@snippet lang="java" :
1760 * long compressLeft(long i, long mask) {
1761 * // This implementation follows the description in Hacker's Delight which
1762 * // is informative. A more optimal implementation is:
1763 * // Long.compress(i, mask) << -Long.bitCount(mask)
1764 * return Long.reverse(
1765 * Long.compress(Long.reverse(i), Long.reverse(mask)));
1766 * }
1767 *
1768 * long sag(long i, long mask) {
1769 * return compressLeft(i, mask) | Long.compress(i, ~mask);
1770 * }
1771 *
1772 * // Separate the sheep from the goats
1773 * sag(0x00000000_CAFEBABEL, 0xFFFFFFFF_FF00FFF0L) == 0x00000000_CABABFEEL
1774 * }
1775 *
1776 * @param i the value whose bits are to be compressed
1777 * @param mask the bit mask
1778 * @return the compressed value
1779 * @see #expand
1780 * @since 19
1781 */
1782 @IntrinsicCandidate
1783 public static long compress(long i, long mask) {
1784 // See Hacker's Delight (2nd ed) section 7.4 Compress, or Generalized Extract
1785
1786 i = i & mask; // Clear irrelevant bits
1787 long maskCount = ~mask << 1; // Count 0's to right
1788
1789 for (int j = 0; j < 6; j++) {
1790 // Parallel prefix
1791 // Mask prefix identifies bits of the mask that have an odd number of 0's to the right
1792 long maskPrefix = parallelSuffix(maskCount);
1793 // Bits to move
1794 long maskMove = maskPrefix & mask;
1795 // Compress mask
1796 mask = (mask ^ maskMove) | (maskMove >>> (1 << j));
1797 // Bits of i to be moved
1798 long t = i & maskMove;
1799 // Compress i
1800 i = (i ^ t) | (t >>> (1 << j));
1801 // Adjust the mask count by identifying bits that have 0 to the right
1802 maskCount = maskCount & ~maskPrefix;
1803 }
1804 return i;
1805 }
1806
1807 /**
1808 * Returns the value obtained by expanding the bits of the
1809 * specified {@code long} value, {@code i}, in accordance with
1810 * the specified bit mask.
1811 * <p>
1812 * For each one-bit value {@code mb} of the mask, from least
1813 * significant to most significant, the next contiguous bit value
1814 * of {@code i} starting at the least significant bit is assigned
1815 * to the expanded value at the same bit location as {@code mb}.
1816 * All other remaining bits of the expanded value are set to zero.
1817 *
1818 * @apiNote
1819 * Consider the simple case of expanding the digits of a hexadecimal
1820 * value:
1821 * {@snippet lang="java" :
1822 * expand(0x0000CABABL, 0xFF00FFF0L) == 0xCA00BAB0L
1823 * }
1824 * Starting from the least significant hexadecimal digit at position 0
1825 * from the right, the mask {@code 0xFF00FFF0} selects the first five
1826 * hexadecimal digits of {@code 0x0000CABAB}. The selected digits occur
1827 * in the resulting expanded value in order at positions 1, 2, 3, 6, and 7.
1828 * <p>
1829 * The following identities all return {@code true} and are helpful to
1830 * understand the behaviour of {@code expand}:
1831 * {@snippet lang="java" :
1832 * // Logically shift right the bit at position 0
1833 * expand(x, 1L << n) == (x & 1) << n
1834 *
1835 * // Logically shift right
1836 * expand(x, -1L << n) == x << n
1837 *
1838 * // Expanding all bits returns the mask
1839 * expand(-1L, m) == m
1840 *
1841 * // Any bits not covered by the mask are ignored
1842 * expand(x, m) == expand(x, m) & m
1843 *
1844 * // Compressing then expanding with the same mask
1845 * expand(compress(x, m), m) == x & m
1846 * }
1847 * <p>
1848 * The select operation for determining the position of the one-bit with
1849 * index {@code n} in a {@code long} value can be implemented as follows:
1850 * {@snippet lang="java" :
1851 * long select(long i, long n) {
1852 * // the one-bit in i (the mask) with index n
1853 * long nthBit = Long.expand(1L << n, i);
1854 * // the bit position of the one-bit with index n
1855 * return Long.numberOfTrailingZeros(nthBit);
1856 * }
1857 *
1858 * // The one-bit with index 0 is at bit position 1
1859 * select(0b10101010_10101010, 0) == 1
1860 * // The one-bit with index 3 is at bit position 7
1861 * select(0b10101010_10101010, 3) == 7
1862 * }
1863 *
1864 * @param i the value whose bits are to be expanded
1865 * @param mask the bit mask
1866 * @return the expanded value
1867 * @see #compress
1868 * @since 19
1869 */
1870 @IntrinsicCandidate
1871 public static long expand(long i, long mask) {
1872 // Save original mask
1873 long originalMask = mask;
1874 // Count 0's to right
1875 long maskCount = ~mask << 1;
1876 long maskPrefix = parallelSuffix(maskCount);
1877 // Bits to move
1878 long maskMove1 = maskPrefix & mask;
1879 // Compress mask
1880 mask = (mask ^ maskMove1) | (maskMove1 >>> (1 << 0));
1881 maskCount = maskCount & ~maskPrefix;
1882
1883 maskPrefix = parallelSuffix(maskCount);
1884 // Bits to move
1885 long maskMove2 = maskPrefix & mask;
1886 // Compress mask
1887 mask = (mask ^ maskMove2) | (maskMove2 >>> (1 << 1));
1888 maskCount = maskCount & ~maskPrefix;
1889
1890 maskPrefix = parallelSuffix(maskCount);
1891 // Bits to move
1892 long maskMove3 = maskPrefix & mask;
1893 // Compress mask
1894 mask = (mask ^ maskMove3) | (maskMove3 >>> (1 << 2));
1895 maskCount = maskCount & ~maskPrefix;
1896
1897 maskPrefix = parallelSuffix(maskCount);
1898 // Bits to move
1899 long maskMove4 = maskPrefix & mask;
1900 // Compress mask
1901 mask = (mask ^ maskMove4) | (maskMove4 >>> (1 << 3));
1902 maskCount = maskCount & ~maskPrefix;
1903
1904 maskPrefix = parallelSuffix(maskCount);
1905 // Bits to move
1906 long maskMove5 = maskPrefix & mask;
1907 // Compress mask
1908 mask = (mask ^ maskMove5) | (maskMove5 >>> (1 << 4));
1909 maskCount = maskCount & ~maskPrefix;
1910
1911 maskPrefix = parallelSuffix(maskCount);
1912 // Bits to move
1913 long maskMove6 = maskPrefix & mask;
1914
1915 long t = i << (1 << 5);
1916 i = (i & ~maskMove6) | (t & maskMove6);
1917 t = i << (1 << 4);
1918 i = (i & ~maskMove5) | (t & maskMove5);
1919 t = i << (1 << 3);
1920 i = (i & ~maskMove4) | (t & maskMove4);
1921 t = i << (1 << 2);
1922 i = (i & ~maskMove3) | (t & maskMove3);
1923 t = i << (1 << 1);
1924 i = (i & ~maskMove2) | (t & maskMove2);
1925 t = i << (1 << 0);
1926 i = (i & ~maskMove1) | (t & maskMove1);
1927
1928 // Clear irrelevant bits
1929 return i & originalMask;
1930 }
1931
1932 @ForceInline
1933 private static long parallelSuffix(long maskCount) {
1934 long maskPrefix = maskCount ^ (maskCount << 1);
1935 maskPrefix = maskPrefix ^ (maskPrefix << 2);
1936 maskPrefix = maskPrefix ^ (maskPrefix << 4);
1937 maskPrefix = maskPrefix ^ (maskPrefix << 8);
1938 maskPrefix = maskPrefix ^ (maskPrefix << 16);
1939 maskPrefix = maskPrefix ^ (maskPrefix << 32);
1940 return maskPrefix;
1941 }
1942
1943 /**
1944 * Returns the signum function of the specified {@code long} value. (The
1945 * return value is -1 if the specified value is negative; 0 if the
1946 * specified value is zero; and 1 if the specified value is positive.)
1947 *
1948 * @param i the value whose signum is to be computed
1949 * @return the signum function of the specified {@code long} value.
1950 * @since 1.5
1951 */
1952 public static int signum(long i) {
1953 // HD, Section 2-7
1954 return (int) ((i >> 63) | (-i >>> 63));
1955 }
1956
1957 /**
1958 * Returns the value obtained by reversing the order of the bytes in the
1959 * two's complement representation of the specified {@code long} value.
1960 *
1961 * @param i the value whose bytes are to be reversed
1962 * @return the value obtained by reversing the bytes in the specified
1963 * {@code long} value.
1964 * @since 1.5
1965 */
1966 @IntrinsicCandidate
1967 public static long reverseBytes(long i) {
1968 i = (i & 0x00ff00ff00ff00ffL) << 8 | (i >>> 8) & 0x00ff00ff00ff00ffL;
1969 return (i << 48) | ((i & 0xffff0000L) << 16) |
1970 ((i >>> 16) & 0xffff0000L) | (i >>> 48);
1971 }
1972
1973 /**
1974 * Adds two {@code long} values together as per the + operator.
1975 *
1976 * @param a the first operand
1977 * @param b the second operand
1978 * @return the sum of {@code a} and {@code b}
1979 * @see java.util.function.BinaryOperator
1980 * @since 1.8
1981 */
1982 public static long sum(long a, long b) {
1983 return a + b;
1984 }
1985
1986 /**
1987 * Returns the greater of two {@code long} values
1988 * as if by calling {@link Math#max(long, long) Math.max}.
1989 *
1990 * @param a the first operand
1991 * @param b the second operand
1992 * @return the greater of {@code a} and {@code b}
1993 * @see java.util.function.BinaryOperator
1994 * @since 1.8
1995 */
1996 public static long max(long a, long b) {
1997 return Math.max(a, b);
1998 }
1999
2000 /**
2001 * Returns the smaller of two {@code long} values
2002 * as if by calling {@link Math#min(long, long) Math.min}.
2003 *
2004 * @param a the first operand
2005 * @param b the second operand
2006 * @return the smaller of {@code a} and {@code b}
2007 * @see java.util.function.BinaryOperator
2008 * @since 1.8
2009 */
2010 public static long min(long a, long b) {
2011 return Math.min(a, b);
2012 }
2013
2014 /**
2015 * Returns an {@link Optional} containing the nominal descriptor for this
2016 * instance, which is the instance itself.
2017 *
2018 * @return an {@link Optional} describing the {@linkplain Long} instance
2019 * @since 12
2020 */
2021 @Override
2022 public Optional<Long> describeConstable() {
2023 return Optional.of(this);
2024 }
2025
2026 /**
2027 * Resolves this instance as a {@link ConstantDesc}, the result of which is
2028 * the instance itself.
2029 *
2030 * @param lookup ignored
2031 * @return the {@linkplain Long} instance
2032 * @since 12
2033 */
2034 @Override
2035 public Long resolveConstantDesc(MethodHandles.Lookup lookup) {
2036 return this;
2037 }
2038
2039 /** use serialVersionUID from JDK 1.0.2 for interoperability */
2040 @java.io.Serial
2041 @Native private static final long serialVersionUID = 4290774380558885855L;
2042 }