1 /*
2 * Copyright (c) 1994, 2023, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 package java.lang;
27
28 import java.lang.annotation.Native;
29 import java.lang.invoke.MethodHandles;
30 import java.lang.constant.Constable;
31 import java.lang.constant.ConstantDesc;
32 import java.math.*;
33 import java.util.Objects;
34 import java.util.Optional;
35
36 import jdk.internal.misc.CDS;
37 import jdk.internal.vm.annotation.ForceInline;
38 import jdk.internal.vm.annotation.IntrinsicCandidate;
39 import jdk.internal.vm.annotation.Stable;
40
41 import static java.lang.Character.digit;
42 import static java.lang.String.COMPACT_STRINGS;
43 import static java.lang.String.LATIN1;
44 import static java.lang.String.UTF16;
45
46 /**
47 * The {@code Long} class wraps a value of the primitive type {@code
48 * long} in an object. An object of type {@code Long} contains a
49 * single field whose type is {@code long}.
50 *
51 * <p> In addition, this class provides several methods for converting
52 * a {@code long} to a {@code String} and a {@code String} to a {@code
53 * long}, as well as other constants and methods useful when dealing
54 * with a {@code long}.
55 *
56 * <p>This is a <a href="{@docRoot}/java.base/java/lang/doc-files/ValueBased.html">value-based</a>
57 * class; programmers should treat instances that are
58 * {@linkplain #equals(Object) equal} as interchangeable and should not
59 * use instances for synchronization, or unpredictable behavior may
60 * occur. For example, in a future release, synchronization may fail.
61 *
62 * <p>Implementation note: The implementations of the "bit twiddling"
63 * methods (such as {@link #highestOneBit(long) highestOneBit} and
64 * {@link #numberOfTrailingZeros(long) numberOfTrailingZeros}) are
65 * based on material from Henry S. Warren, Jr.'s <i>Hacker's
66 * Delight</i>, (Addison Wesley, 2002).
67 *
68 * @author Lee Boynton
69 * @author Arthur van Hoff
70 * @author Josh Bloch
71 * @author Joseph D. Darcy
72 * @since 1.0
73 */
74 @jdk.internal.MigratedValueClass
75 @jdk.internal.ValueBased
76 public final class Long extends Number
77 implements Comparable<Long>, Constable, ConstantDesc {
78 /**
79 * A constant holding the minimum value a {@code long} can
80 * have, -2<sup>63</sup>.
81 */
82 @Native public static final long MIN_VALUE = 0x8000000000000000L;
83
84 /**
85 * A constant holding the maximum value a {@code long} can
86 * have, 2<sup>63</sup>-1.
87 */
88 @Native public static final long MAX_VALUE = 0x7fffffffffffffffL;
89
90 /**
91 * The {@code Class} instance representing the primitive type
92 * {@code long}.
93 *
94 * @since 1.1
95 */
96 @SuppressWarnings("unchecked")
97 public static final Class<Long> TYPE = (Class<Long>) Class.getPrimitiveClass("long");
98
99 /**
100 * Returns a string representation of the first argument in the
101 * radix specified by the second argument.
102 *
103 * <p>If the radix is smaller than {@code Character.MIN_RADIX}
104 * or larger than {@code Character.MAX_RADIX}, then the radix
105 * {@code 10} is used instead.
106 *
107 * <p>If the first argument is negative, the first element of the
108 * result is the ASCII minus sign {@code '-'}
109 * ({@code '\u005Cu002d'}). If the first argument is not
110 * negative, no sign character appears in the result.
111 *
112 * <p>The remaining characters of the result represent the magnitude
113 * of the first argument. If the magnitude is zero, it is
114 * represented by a single zero character {@code '0'}
115 * ({@code '\u005Cu0030'}); otherwise, the first character of
116 * the representation of the magnitude will not be the zero
117 * character. The following ASCII characters are used as digits:
118 *
119 * <blockquote>
120 * {@code 0123456789abcdefghijklmnopqrstuvwxyz}
121 * </blockquote>
122 *
123 * These are {@code '\u005Cu0030'} through
124 * {@code '\u005Cu0039'} and {@code '\u005Cu0061'} through
125 * {@code '\u005Cu007a'}. If {@code radix} is
126 * <var>N</var>, then the first <var>N</var> of these characters
127 * are used as radix-<var>N</var> digits in the order shown. Thus,
128 * the digits for hexadecimal (radix 16) are
129 * {@code 0123456789abcdef}. If uppercase letters are
130 * desired, the {@link java.lang.String#toUpperCase()} method may
131 * be called on the result:
132 *
133 * <blockquote>
134 * {@code Long.toString(n, 16).toUpperCase()}
135 * </blockquote>
136 *
137 * @param i a {@code long} to be converted to a string.
138 * @param radix the radix to use in the string representation.
139 * @return a string representation of the argument in the specified radix.
140 * @see java.lang.Character#MAX_RADIX
141 * @see java.lang.Character#MIN_RADIX
142 */
143 public static String toString(long i, int radix) {
144 if (radix < Character.MIN_RADIX || radix > Character.MAX_RADIX)
145 radix = 10;
146 if (radix == 10)
147 return toString(i);
148
149 if (COMPACT_STRINGS) {
150 byte[] buf = new byte[65];
151 int charPos = 64;
152 boolean negative = (i < 0);
153
154 if (!negative) {
155 i = -i;
156 }
157
158 while (i <= -radix) {
159 buf[charPos--] = (byte)Integer.digits[(int)(-(i % radix))];
160 i = i / radix;
161 }
162 buf[charPos] = (byte)Integer.digits[(int)(-i)];
163
164 if (negative) {
165 buf[--charPos] = '-';
166 }
167 return StringLatin1.newString(buf, charPos, (65 - charPos));
168 }
169 return toStringUTF16(i, radix);
170 }
171
172 private static String toStringUTF16(long i, int radix) {
173 byte[] buf = new byte[65 * 2];
174 int charPos = 64;
175 boolean negative = (i < 0);
176 if (!negative) {
177 i = -i;
178 }
179 while (i <= -radix) {
180 StringUTF16.putChar(buf, charPos--, Integer.digits[(int)(-(i % radix))]);
181 i = i / radix;
182 }
183 StringUTF16.putChar(buf, charPos, Integer.digits[(int)(-i)]);
184 if (negative) {
185 StringUTF16.putChar(buf, --charPos, '-');
186 }
187 return StringUTF16.newString(buf, charPos, (65 - charPos));
188 }
189
190 /**
191 * Returns a string representation of the first argument as an
192 * unsigned integer value in the radix specified by the second
193 * argument.
194 *
195 * <p>If the radix is smaller than {@code Character.MIN_RADIX}
196 * or larger than {@code Character.MAX_RADIX}, then the radix
197 * {@code 10} is used instead.
198 *
199 * <p>Note that since the first argument is treated as an unsigned
200 * value, no leading sign character is printed.
201 *
202 * <p>If the magnitude is zero, it is represented by a single zero
203 * character {@code '0'} ({@code '\u005Cu0030'}); otherwise,
204 * the first character of the representation of the magnitude will
205 * not be the zero character.
206 *
207 * <p>The behavior of radixes and the characters used as digits
208 * are the same as {@link #toString(long, int) toString}.
209 *
210 * @param i an integer to be converted to an unsigned string.
211 * @param radix the radix to use in the string representation.
212 * @return an unsigned string representation of the argument in the specified radix.
213 * @see #toString(long, int)
214 * @since 1.8
215 */
216 public static String toUnsignedString(long i, int radix) {
217 if (i >= 0)
218 return toString(i, radix);
219 else {
220 return switch (radix) {
221 case 2 -> toBinaryString(i);
222 case 4 -> toUnsignedString0(i, 2);
223 case 8 -> toOctalString(i);
224 case 10 -> {
225 /*
226 * We can get the effect of an unsigned division by 10
227 * on a long value by first shifting right, yielding a
228 * positive value, and then dividing by 5. This
229 * allows the last digit and preceding digits to be
230 * isolated more quickly than by an initial conversion
231 * to BigInteger.
232 */
233 long quot = (i >>> 1) / 5;
234 long rem = i - quot * 10;
235 yield toString(quot) + rem;
236 }
237 case 16 -> toHexString(i);
238 case 32 -> toUnsignedString0(i, 5);
239 default -> toUnsignedBigInteger(i).toString(radix);
240 };
241 }
242 }
243
244 /**
245 * Return a BigInteger equal to the unsigned value of the
246 * argument.
247 */
248 private static BigInteger toUnsignedBigInteger(long i) {
249 if (i >= 0L)
250 return BigInteger.valueOf(i);
251 else {
252 int upper = (int) (i >>> 32);
253 int lower = (int) i;
254
255 // return (upper << 32) + lower
256 return (BigInteger.valueOf(Integer.toUnsignedLong(upper))).shiftLeft(32).
257 add(BigInteger.valueOf(Integer.toUnsignedLong(lower)));
258 }
259 }
260
261 /**
262 * Returns a string representation of the {@code long}
263 * argument as an unsigned integer in base 16.
264 *
265 * <p>The unsigned {@code long} value is the argument plus
266 * 2<sup>64</sup> if the argument is negative; otherwise, it is
267 * equal to the argument. This value is converted to a string of
268 * ASCII digits in hexadecimal (base 16) with no extra
269 * leading {@code 0}s.
270 *
271 * <p>The value of the argument can be recovered from the returned
272 * string {@code s} by calling {@link
273 * Long#parseUnsignedLong(String, int) Long.parseUnsignedLong(s,
274 * 16)}.
275 *
276 * <p>If the unsigned magnitude is zero, it is represented by a
277 * single zero character {@code '0'} ({@code '\u005Cu0030'});
278 * otherwise, the first character of the representation of the
279 * unsigned magnitude will not be the zero character. The
280 * following characters are used as hexadecimal digits:
281 *
282 * <blockquote>
283 * {@code 0123456789abcdef}
284 * </blockquote>
285 *
286 * These are the characters {@code '\u005Cu0030'} through
287 * {@code '\u005Cu0039'} and {@code '\u005Cu0061'} through
288 * {@code '\u005Cu0066'}. If uppercase letters are desired,
289 * the {@link java.lang.String#toUpperCase()} method may be called
290 * on the result:
291 *
292 * <blockquote>
293 * {@code Long.toHexString(n).toUpperCase()}
294 * </blockquote>
295 *
296 * @apiNote
297 * The {@link java.util.HexFormat} class provides formatting and parsing
298 * of byte arrays and primitives to return a string or adding to an {@link Appendable}.
299 * {@code HexFormat} formats and parses uppercase or lowercase hexadecimal characters,
300 * with leading zeros and for byte arrays includes for each byte
301 * a delimiter, prefix, and suffix.
302 *
303 * @param i a {@code long} to be converted to a string.
304 * @return the string representation of the unsigned {@code long}
305 * value represented by the argument in hexadecimal
306 * (base 16).
307 * @see java.util.HexFormat
308 * @see #parseUnsignedLong(String, int)
309 * @see #toUnsignedString(long, int)
310 * @since 1.0.2
311 */
312 public static String toHexString(long i) {
313 return toUnsignedString0(i, 4);
314 }
315
316 /**
317 * Returns a string representation of the {@code long}
318 * argument as an unsigned integer in base 8.
319 *
320 * <p>The unsigned {@code long} value is the argument plus
321 * 2<sup>64</sup> if the argument is negative; otherwise, it is
322 * equal to the argument. This value is converted to a string of
323 * ASCII digits in octal (base 8) with no extra leading
324 * {@code 0}s.
325 *
326 * <p>The value of the argument can be recovered from the returned
327 * string {@code s} by calling {@link
328 * Long#parseUnsignedLong(String, int) Long.parseUnsignedLong(s,
329 * 8)}.
330 *
331 * <p>If the unsigned magnitude is zero, it is represented by a
332 * single zero character {@code '0'} ({@code '\u005Cu0030'});
333 * otherwise, the first character of the representation of the
334 * unsigned magnitude will not be the zero character. The
335 * following characters are used as octal digits:
336 *
337 * <blockquote>
338 * {@code 01234567}
339 * </blockquote>
340 *
341 * These are the characters {@code '\u005Cu0030'} through
342 * {@code '\u005Cu0037'}.
343 *
344 * @param i a {@code long} to be converted to a string.
345 * @return the string representation of the unsigned {@code long}
346 * value represented by the argument in octal (base 8).
347 * @see #parseUnsignedLong(String, int)
348 * @see #toUnsignedString(long, int)
349 * @since 1.0.2
350 */
351 public static String toOctalString(long i) {
352 return toUnsignedString0(i, 3);
353 }
354
355 /**
356 * Returns a string representation of the {@code long}
357 * argument as an unsigned integer in base 2.
358 *
359 * <p>The unsigned {@code long} value is the argument plus
360 * 2<sup>64</sup> if the argument is negative; otherwise, it is
361 * equal to the argument. This value is converted to a string of
362 * ASCII digits in binary (base 2) with no extra leading
363 * {@code 0}s.
364 *
365 * <p>The value of the argument can be recovered from the returned
366 * string {@code s} by calling {@link
367 * Long#parseUnsignedLong(String, int) Long.parseUnsignedLong(s,
368 * 2)}.
369 *
370 * <p>If the unsigned magnitude is zero, it is represented by a
371 * single zero character {@code '0'} ({@code '\u005Cu0030'});
372 * otherwise, the first character of the representation of the
373 * unsigned magnitude will not be the zero character. The
374 * characters {@code '0'} ({@code '\u005Cu0030'}) and {@code
375 * '1'} ({@code '\u005Cu0031'}) are used as binary digits.
376 *
377 * @param i a {@code long} to be converted to a string.
378 * @return the string representation of the unsigned {@code long}
379 * value represented by the argument in binary (base 2).
380 * @see #parseUnsignedLong(String, int)
381 * @see #toUnsignedString(long, int)
382 * @since 1.0.2
383 */
384 public static String toBinaryString(long i) {
385 return toUnsignedString0(i, 1);
386 }
387
388 /**
389 * Format a long (treated as unsigned) into a String.
390 * @param val the value to format
391 * @param shift the log2 of the base to format in (4 for hex, 3 for octal, 1 for binary)
392 */
393 static String toUnsignedString0(long val, int shift) {
394 // assert shift > 0 && shift <=5 : "Illegal shift value";
395 int mag = Long.SIZE - Long.numberOfLeadingZeros(val);
396 int chars = Math.max(((mag + (shift - 1)) / shift), 1);
397 if (COMPACT_STRINGS) {
398 byte[] buf = new byte[chars];
399 formatUnsignedLong0(val, shift, buf, 0, chars);
400 return new String(buf, LATIN1);
401 } else {
402 byte[] buf = new byte[chars * 2];
403 formatUnsignedLong0UTF16(val, shift, buf, 0, chars);
404 return new String(buf, UTF16);
405 }
406 }
407
408 /**
409 * Format a long (treated as unsigned) into a byte buffer (LATIN1 version). If
410 * {@code len} exceeds the formatted ASCII representation of {@code val},
411 * {@code buf} will be padded with leading zeroes.
412 *
413 * @param val the unsigned long to format
414 * @param shift the log2 of the base to format in (4 for hex, 3 for octal, 1 for binary)
415 * @param buf the byte buffer to write to
416 * @param offset the offset in the destination buffer to start at
417 * @param len the number of characters to write
418 */
419 private static void formatUnsignedLong0(long val, int shift, byte[] buf, int offset, int len) {
420 int charPos = offset + len;
421 int radix = 1 << shift;
422 int mask = radix - 1;
423 do {
424 buf[--charPos] = (byte)Integer.digits[((int) val) & mask];
425 val >>>= shift;
426 } while (charPos > offset);
427 }
428
429 /**
430 * Format a long (treated as unsigned) into a byte buffer (UTF16 version). If
431 * {@code len} exceeds the formatted ASCII representation of {@code val},
432 * {@code buf} will be padded with leading zeroes.
433 *
434 * @param val the unsigned long to format
435 * @param shift the log2 of the base to format in (4 for hex, 3 for octal, 1 for binary)
436 * @param buf the byte buffer to write to
437 * @param offset the offset in the destination buffer to start at
438 * @param len the number of characters to write
439 */
440 private static void formatUnsignedLong0UTF16(long val, int shift, byte[] buf, int offset, int len) {
441 int charPos = offset + len;
442 int radix = 1 << shift;
443 int mask = radix - 1;
444 do {
445 StringUTF16.putChar(buf, --charPos, Integer.digits[((int) val) & mask]);
446 val >>>= shift;
447 } while (charPos > offset);
448 }
449
450 /**
451 * Returns a {@code String} object representing the specified
452 * {@code long}. The argument is converted to signed decimal
453 * representation and returned as a string, exactly as if the
454 * argument and the radix 10 were given as arguments to the {@link
455 * #toString(long, int)} method.
456 *
457 * @param i a {@code long} to be converted.
458 * @return a string representation of the argument in base 10.
459 */
460 public static String toString(long i) {
461 int size = stringSize(i);
462 if (COMPACT_STRINGS) {
463 byte[] buf = new byte[size];
464 StringLatin1.getChars(i, size, buf);
465 return new String(buf, LATIN1);
466 } else {
467 byte[] buf = new byte[size * 2];
468 StringUTF16.getChars(i, size, buf);
469 return new String(buf, UTF16);
470 }
471 }
472
473 /**
474 * Returns a string representation of the argument as an unsigned
475 * decimal value.
476 *
477 * The argument is converted to unsigned decimal representation
478 * and returned as a string exactly as if the argument and radix
479 * 10 were given as arguments to the {@link #toUnsignedString(long,
480 * int)} method.
481 *
482 * @param i an integer to be converted to an unsigned string.
483 * @return an unsigned string representation of the argument.
484 * @see #toUnsignedString(long, int)
485 * @since 1.8
486 */
487 public static String toUnsignedString(long i) {
488 return toUnsignedString(i, 10);
489 }
490
491 /**
492 * Returns the string representation size for a given long value.
493 *
494 * @param x long value
495 * @return string size
496 *
497 * @implNote There are other ways to compute this: e.g. binary search,
498 * but values are biased heavily towards zero, and therefore linear search
499 * wins. The iteration results are also routinely inlined in the generated
500 * code after loop unrolling.
501 */
502 static int stringSize(long x) {
503 int d = 1;
504 if (x >= 0) {
505 d = 0;
506 x = -x;
507 }
508 long p = -10;
509 for (int i = 1; i < 19; i++) {
510 if (x > p)
511 return i + d;
512 p = 10 * p;
513 }
514 return 19 + d;
515 }
516
517 /**
518 * Parses the string argument as a signed {@code long} in the
519 * radix specified by the second argument. The characters in the
520 * string must all be digits of the specified radix (as determined
521 * by whether {@link java.lang.Character#digit(char, int)} returns
522 * a nonnegative value), except that the first character may be an
523 * ASCII minus sign {@code '-'} ({@code '\u005Cu002D'}) to
524 * indicate a negative value or an ASCII plus sign {@code '+'}
525 * ({@code '\u005Cu002B'}) to indicate a positive value. The
526 * resulting {@code long} value is returned.
527 *
528 * <p>Note that neither the character {@code L}
529 * ({@code '\u005Cu004C'}) nor {@code l}
530 * ({@code '\u005Cu006C'}) is permitted to appear at the end
531 * of the string as a type indicator, as would be permitted in
532 * Java programming language source code - except that either
533 * {@code L} or {@code l} may appear as a digit for a
534 * radix greater than or equal to 22.
535 *
536 * <p>An exception of type {@code NumberFormatException} is
537 * thrown if any of the following situations occurs:
538 * <ul>
539 *
540 * <li>The first argument is {@code null} or is a string of
541 * length zero.
542 *
543 * <li>The {@code radix} is either smaller than {@link
544 * java.lang.Character#MIN_RADIX} or larger than {@link
545 * java.lang.Character#MAX_RADIX}.
546 *
547 * <li>Any character of the string is not a digit of the specified
548 * radix, except that the first character may be a minus sign
549 * {@code '-'} ({@code '\u005Cu002d'}) or plus sign {@code
550 * '+'} ({@code '\u005Cu002B'}) provided that the string is
551 * longer than length 1.
552 *
553 * <li>The value represented by the string is not a value of type
554 * {@code long}.
555 * </ul>
556 *
557 * <p>Examples:
558 * <blockquote><pre>
559 * parseLong("0", 10) returns 0L
560 * parseLong("473", 10) returns 473L
561 * parseLong("+42", 10) returns 42L
562 * parseLong("-0", 10) returns 0L
563 * parseLong("-FF", 16) returns -255L
564 * parseLong("1100110", 2) returns 102L
565 * parseLong("99", 8) throws a NumberFormatException
566 * parseLong("Hazelnut", 10) throws a NumberFormatException
567 * parseLong("Hazelnut", 36) returns 1356099454469L
568 * </pre></blockquote>
569 *
570 * @param s the {@code String} containing the
571 * {@code long} representation to be parsed.
572 * @param radix the radix to be used while parsing {@code s}.
573 * @return the {@code long} represented by the string argument in
574 * the specified radix.
575 * @throws NumberFormatException if the string does not contain a
576 * parsable {@code long}.
577 */
578 public static long parseLong(String s, int radix)
579 throws NumberFormatException {
580 if (s == null) {
581 throw new NumberFormatException("Cannot parse null string");
582 }
583
584 if (radix < Character.MIN_RADIX) {
585 throw new NumberFormatException(String.format(
586 "radix %s less than Character.MIN_RADIX", radix));
587 }
588
589 if (radix > Character.MAX_RADIX) {
590 throw new NumberFormatException(String.format(
591 "radix %s greater than Character.MAX_RADIX", radix));
592 }
593
594 int len = s.length();
595 if (len == 0) {
596 throw NumberFormatException.forInputString("", radix);
597 }
598 int digit = ~0xFF;
599 int i = 0;
600 char firstChar = s.charAt(i++);
601 if (firstChar != '-' && firstChar != '+') {
602 digit = digit(firstChar, radix);
603 }
604 if (digit >= 0 || digit == ~0xFF && len > 1) {
605 long limit = firstChar != '-' ? MIN_VALUE + 1 : MIN_VALUE;
606 long multmin = limit / radix;
607 long result = -(digit & 0xFF);
608 boolean inRange = true;
609 /* Accumulating negatively avoids surprises near MAX_VALUE */
610 while (i < len && (digit = digit(s.charAt(i++), radix)) >= 0
611 && (inRange = result > multmin
612 || result == multmin && digit <= (int) (radix * multmin - limit))) {
613 result = radix * result - digit;
614 }
615 if (inRange && i == len && digit >= 0) {
616 return firstChar != '-' ? -result : result;
617 }
618 }
619 throw NumberFormatException.forInputString(s, radix);
620 }
621
622 /**
623 * Parses the {@link CharSequence} argument as a signed {@code long} in
624 * the specified {@code radix}, beginning at the specified
625 * {@code beginIndex} and extending to {@code endIndex - 1}.
626 *
627 * <p>The method does not take steps to guard against the
628 * {@code CharSequence} being mutated while parsing.
629 *
630 * @param s the {@code CharSequence} containing the {@code long}
631 * representation to be parsed
632 * @param beginIndex the beginning index, inclusive.
633 * @param endIndex the ending index, exclusive.
634 * @param radix the radix to be used while parsing {@code s}.
635 * @return the signed {@code long} represented by the subsequence in
636 * the specified radix.
637 * @throws NullPointerException if {@code s} is null.
638 * @throws IndexOutOfBoundsException if {@code beginIndex} is
639 * negative, or if {@code beginIndex} is greater than
640 * {@code endIndex} or if {@code endIndex} is greater than
641 * {@code s.length()}.
642 * @throws NumberFormatException if the {@code CharSequence} does not
643 * contain a parsable {@code long} in the specified
644 * {@code radix}, or if {@code radix} is either smaller than
645 * {@link java.lang.Character#MIN_RADIX} or larger than
646 * {@link java.lang.Character#MAX_RADIX}.
647 * @since 9
648 */
649 public static long parseLong(CharSequence s, int beginIndex, int endIndex, int radix)
650 throws NumberFormatException {
651 Objects.requireNonNull(s);
652 Objects.checkFromToIndex(beginIndex, endIndex, s.length());
653
654 if (radix < Character.MIN_RADIX) {
655 throw new NumberFormatException(String.format(
656 "radix %s less than Character.MIN_RADIX", radix));
657 }
658
659 if (radix > Character.MAX_RADIX) {
660 throw new NumberFormatException(String.format(
661 "radix %s greater than Character.MAX_RADIX", radix));
662 }
663
664 /*
665 * While s can be concurrently modified, it is ensured that each
666 * of its characters is read at most once, from lower to higher indices.
667 * This is obtained by reading them using the pattern s.charAt(i++),
668 * and by not updating i anywhere else.
669 */
670 if (beginIndex == endIndex) {
671 throw NumberFormatException.forInputString("", radix);
672 }
673 int digit = ~0xFF; // ~0xFF means firstChar char is sign
674 int i = beginIndex;
675 char firstChar = s.charAt(i++);
676 if (firstChar != '-' && firstChar != '+') {
677 digit = digit(firstChar, radix);
678 }
679 if (digit >= 0 || digit == ~0xFF && endIndex - beginIndex > 1) {
680 long limit = firstChar != '-' ? MIN_VALUE + 1 : MIN_VALUE;
681 long multmin = limit / radix;
682 long result = -(digit & 0xFF);
683 boolean inRange = true;
684 /* Accumulating negatively avoids surprises near MAX_VALUE */
685 while (i < endIndex && (digit = digit(s.charAt(i++), radix)) >= 0
686 && (inRange = result > multmin
687 || result == multmin && digit <= (int) (radix * multmin - limit))) {
688 result = radix * result - digit;
689 }
690 if (inRange && i == endIndex && digit >= 0) {
691 return firstChar != '-' ? -result : result;
692 }
693 }
694 throw NumberFormatException.forCharSequence(s, beginIndex,
695 endIndex, i - (digit < -1 ? 0 : 1));
696 }
697
698 /**
699 * Parses the string argument as a signed decimal {@code long}.
700 * The characters in the string must all be decimal digits, except
701 * that the first character may be an ASCII minus sign {@code '-'}
702 * ({@code \u005Cu002D'}) to indicate a negative value or an
703 * ASCII plus sign {@code '+'} ({@code '\u005Cu002B'}) to
704 * indicate a positive value. The resulting {@code long} value is
705 * returned, exactly as if the argument and the radix {@code 10}
706 * were given as arguments to the {@link
707 * #parseLong(java.lang.String, int)} method.
708 *
709 * <p>Note that neither the character {@code L}
710 * ({@code '\u005Cu004C'}) nor {@code l}
711 * ({@code '\u005Cu006C'}) is permitted to appear at the end
712 * of the string as a type indicator, as would be permitted in
713 * Java programming language source code.
714 *
715 * @param s a {@code String} containing the {@code long}
716 * representation to be parsed
717 * @return the {@code long} represented by the argument in
718 * decimal.
719 * @throws NumberFormatException if the string does not contain a
720 * parsable {@code long}.
721 */
722 public static long parseLong(String s) throws NumberFormatException {
723 return parseLong(s, 10);
724 }
725
726 /**
727 * Parses the string argument as an unsigned {@code long} in the
728 * radix specified by the second argument. An unsigned integer
729 * maps the values usually associated with negative numbers to
730 * positive numbers larger than {@code MAX_VALUE}.
731 *
732 * The characters in the string must all be digits of the
733 * specified radix (as determined by whether {@link
734 * java.lang.Character#digit(char, int)} returns a nonnegative
735 * value), except that the first character may be an ASCII plus
736 * sign {@code '+'} ({@code '\u005Cu002B'}). The resulting
737 * integer value is returned.
738 *
739 * <p>An exception of type {@code NumberFormatException} is
740 * thrown if any of the following situations occurs:
741 * <ul>
742 * <li>The first argument is {@code null} or is a string of
743 * length zero.
744 *
745 * <li>The radix is either smaller than
746 * {@link java.lang.Character#MIN_RADIX} or
747 * larger than {@link java.lang.Character#MAX_RADIX}.
748 *
749 * <li>Any character of the string is not a digit of the specified
750 * radix, except that the first character may be a plus sign
751 * {@code '+'} ({@code '\u005Cu002B'}) provided that the
752 * string is longer than length 1.
753 *
754 * <li>The value represented by the string is larger than the
755 * largest unsigned {@code long}, 2<sup>64</sup>-1.
756 *
757 * </ul>
758 *
759 *
760 * @param s the {@code String} containing the unsigned integer
761 * representation to be parsed
762 * @param radix the radix to be used while parsing {@code s}.
763 * @return the unsigned {@code long} represented by the string
764 * argument in the specified radix.
765 * @throws NumberFormatException if the {@code String}
766 * does not contain a parsable {@code long}.
767 * @since 1.8
768 */
769 public static long parseUnsignedLong(String s, int radix)
770 throws NumberFormatException {
771 if (s == null) {
772 throw new NumberFormatException("Cannot parse null string");
773 }
774
775 if (radix < Character.MIN_RADIX) {
776 throw new NumberFormatException(String.format(
777 "radix %s less than Character.MIN_RADIX", radix));
778 }
779
780 if (radix > Character.MAX_RADIX) {
781 throw new NumberFormatException(String.format(
782 "radix %s greater than Character.MAX_RADIX", radix));
783 }
784
785 int len = s.length();
786 if (len == 0) {
787 throw NumberFormatException.forInputString(s, radix);
788 }
789 int i = 0;
790 char firstChar = s.charAt(i++);
791 if (firstChar == '-') {
792 throw new NumberFormatException(String.format(
793 "Illegal leading minus sign on unsigned string %s.", s));
794 }
795 int digit = ~0xFF;
796 if (firstChar != '+') {
797 digit = digit(firstChar, radix);
798 }
799 if (digit >= 0 || digit == ~0xFF && len > 1) {
800 long multmax = divideUnsigned(-1L, radix); // -1L is max unsigned long
801 long result = digit & 0xFF;
802 boolean inRange = true;
803 while (i < len && (digit = digit(s.charAt(i++), radix)) >= 0
804 && (inRange = compareUnsigned(result, multmax) < 0
805 || result == multmax && digit < (int) (-radix * multmax))) {
806 result = radix * result + digit;
807 }
808 if (inRange && i == len && digit >= 0) {
809 return result;
810 }
811 }
812 if (digit < 0) {
813 throw NumberFormatException.forInputString(s, radix);
814 }
815 throw new NumberFormatException(String.format(
816 "String value %s exceeds range of unsigned long.", s));
817 }
818
819 /**
820 * Parses the {@link CharSequence} argument as an unsigned {@code long} in
821 * the specified {@code radix}, beginning at the specified
822 * {@code beginIndex} and extending to {@code endIndex - 1}.
823 *
824 * <p>The method does not take steps to guard against the
825 * {@code CharSequence} being mutated while parsing.
826 *
827 * @param s the {@code CharSequence} containing the unsigned
828 * {@code long} representation to be parsed
829 * @param beginIndex the beginning index, inclusive.
830 * @param endIndex the ending index, exclusive.
831 * @param radix the radix to be used while parsing {@code s}.
832 * @return the unsigned {@code long} represented by the subsequence in
833 * the specified radix.
834 * @throws NullPointerException if {@code s} is null.
835 * @throws IndexOutOfBoundsException if {@code beginIndex} is
836 * negative, or if {@code beginIndex} is greater than
837 * {@code endIndex} or if {@code endIndex} is greater than
838 * {@code s.length()}.
839 * @throws NumberFormatException if the {@code CharSequence} does not
840 * contain a parsable unsigned {@code long} in the specified
841 * {@code radix}, or if {@code radix} is either smaller than
842 * {@link java.lang.Character#MIN_RADIX} or larger than
843 * {@link java.lang.Character#MAX_RADIX}.
844 * @since 9
845 */
846 public static long parseUnsignedLong(CharSequence s, int beginIndex, int endIndex, int radix)
847 throws NumberFormatException {
848 Objects.requireNonNull(s);
849 Objects.checkFromToIndex(beginIndex, endIndex, s.length());
850
851 if (radix < Character.MIN_RADIX) {
852 throw new NumberFormatException(String.format(
853 "radix %s less than Character.MIN_RADIX", radix));
854 }
855
856 if (radix > Character.MAX_RADIX) {
857 throw new NumberFormatException(String.format(
858 "radix %s greater than Character.MAX_RADIX", radix));
859 }
860
861 /*
862 * While s can be concurrently modified, it is ensured that each
863 * of its characters is read at most once, from lower to higher indices.
864 * This is obtained by reading them using the pattern s.charAt(i++),
865 * and by not updating i anywhere else.
866 */
867 if (beginIndex == endIndex) {
868 throw NumberFormatException.forInputString("", radix);
869 }
870 int i = beginIndex;
871 char firstChar = s.charAt(i++);
872 if (firstChar == '-') {
873 throw new NumberFormatException(
874 "Illegal leading minus sign on unsigned string " + s + ".");
875 }
876 int digit = ~0xFF;
877 if (firstChar != '+') {
878 digit = digit(firstChar, radix);
879 }
880 if (digit >= 0 || digit == ~0xFF && endIndex - beginIndex > 1) {
881 long multmax = divideUnsigned(-1L, radix); // -1L is max unsigned long
882 long result = digit & 0xFF;
883 boolean inRange = true;
884 while (i < endIndex && (digit = digit(s.charAt(i++), radix)) >= 0
885 && (inRange = compareUnsigned(result, multmax) < 0
886 || result == multmax && digit < (int) (-radix * multmax))) {
887 result = radix * result + digit;
888 }
889 if (inRange && i == endIndex && digit >= 0) {
890 return result;
891 }
892 }
893 if (digit < 0) {
894 throw NumberFormatException.forCharSequence(s, beginIndex,
895 endIndex, i - (digit < -1 ? 0 : 1));
896 }
897 throw new NumberFormatException(String.format(
898 "String value %s exceeds range of unsigned long.", s));
899 }
900
901 /**
902 * Parses the string argument as an unsigned decimal {@code long}. The
903 * characters in the string must all be decimal digits, except
904 * that the first character may be an ASCII plus sign {@code
905 * '+'} ({@code '\u005Cu002B'}). The resulting integer value
906 * is returned, exactly as if the argument and the radix 10 were
907 * given as arguments to the {@link
908 * #parseUnsignedLong(java.lang.String, int)} method.
909 *
910 * @param s a {@code String} containing the unsigned {@code long}
911 * representation to be parsed
912 * @return the unsigned {@code long} value represented by the decimal string argument
913 * @throws NumberFormatException if the string does not contain a
914 * parsable unsigned integer.
915 * @since 1.8
916 */
917 public static long parseUnsignedLong(String s) throws NumberFormatException {
918 return parseUnsignedLong(s, 10);
919 }
920
921 /**
922 * Returns a {@code Long} object holding the value
923 * extracted from the specified {@code String} when parsed
924 * with the radix given by the second argument. The first
925 * argument is interpreted as representing a signed
926 * {@code long} in the radix specified by the second
927 * argument, exactly as if the arguments were given to the {@link
928 * #parseLong(java.lang.String, int)} method. The result is a
929 * {@code Long} object that represents the {@code long}
930 * value specified by the string.
931 *
932 * <p>In other words, this method returns a {@code Long} object equal
933 * to the value of:
934 *
935 * <blockquote>
936 * {@code Long.valueOf(Long.parseLong(s, radix))}
937 * </blockquote>
938 *
939 * @param s the string to be parsed
940 * @param radix the radix to be used in interpreting {@code s}
941 * @return a {@code Long} object holding the value
942 * represented by the string argument in the specified
943 * radix.
944 * @throws NumberFormatException If the {@code String} does not
945 * contain a parsable {@code long}.
946 */
947 public static Long valueOf(String s, int radix) throws NumberFormatException {
948 return Long.valueOf(parseLong(s, radix));
949 }
950
951 /**
952 * Returns a {@code Long} object holding the value
953 * of the specified {@code String}. The argument is
954 * interpreted as representing a signed decimal {@code long},
955 * exactly as if the argument were given to the {@link
956 * #parseLong(java.lang.String)} method. The result is a
957 * {@code Long} object that represents the integer value
958 * specified by the string.
959 *
960 * <p>In other words, this method returns a {@code Long} object
961 * equal to the value of:
962 *
963 * <blockquote>
964 * {@code Long.valueOf(Long.parseLong(s))}
965 * </blockquote>
966 *
967 * @param s the string to be parsed.
968 * @return a {@code Long} object holding the value
969 * represented by the string argument.
970 * @throws NumberFormatException If the string cannot be parsed
971 * as a {@code long}.
972 */
973 public static Long valueOf(String s) throws NumberFormatException
974 {
975 return Long.valueOf(parseLong(s, 10));
976 }
977
978 private static final class LongCache {
979 private LongCache() {}
980
981 @Stable
982 static final Long[] cache;
983 static Long[] archivedCache;
984
985 static {
986 int size = -(-128) + 127 + 1;
987
988 // Load and use the archived cache if it exists
989 CDS.initializeFromArchive(LongCache.class);
990 if (archivedCache == null || archivedCache.length != size) {
991 Long[] c = new Long[size];
992 long value = -128;
993 for(int i = 0; i < size; i++) {
994 c[i] = new Long(value++);
995 }
996 archivedCache = c;
997 }
998 cache = archivedCache;
999 }
1000 }
1001
1002 /**
1003 * Returns a {@code Long} instance representing the specified
1004 * {@code long} value.
1005 * If a new {@code Long} instance is not required, this method
1006 * should generally be used in preference to the constructor
1007 * {@link #Long(long)}, as this method is likely to yield
1008 * significantly better space and time performance by caching
1009 * frequently requested values.
1010 *
1011 * This method will always cache values in the range -128 to 127,
1012 * inclusive, and may cache other values outside of this range.
1013 *
1014 * @param l a long value.
1015 * @return a {@code Long} instance representing {@code l}.
1016 * @since 1.5
1017 */
1018 @IntrinsicCandidate
1019 public static Long valueOf(long l) {
1020 final int offset = 128;
1021 if (l >= -128 && l <= 127) { // will cache
1022 return LongCache.cache[(int)l + offset];
1023 }
1024 return new Long(l);
1025 }
1026
1027 /**
1028 * Decodes a {@code String} into a {@code Long}.
1029 * Accepts decimal, hexadecimal, and octal numbers given by the
1030 * following grammar:
1031 *
1032 * <blockquote>
1033 * <dl>
1034 * <dt><i>DecodableString:</i>
1035 * <dd><i>Sign<sub>opt</sub> DecimalNumeral</i>
1036 * <dd><i>Sign<sub>opt</sub></i> {@code 0x} <i>HexDigits</i>
1037 * <dd><i>Sign<sub>opt</sub></i> {@code 0X} <i>HexDigits</i>
1038 * <dd><i>Sign<sub>opt</sub></i> {@code #} <i>HexDigits</i>
1039 * <dd><i>Sign<sub>opt</sub></i> {@code 0} <i>OctalDigits</i>
1040 *
1041 * <dt><i>Sign:</i>
1042 * <dd>{@code -}
1043 * <dd>{@code +}
1044 * </dl>
1045 * </blockquote>
1046 *
1047 * <i>DecimalNumeral</i>, <i>HexDigits</i>, and <i>OctalDigits</i>
1048 * are as defined in section {@jls 3.10.1} of
1049 * <cite>The Java Language Specification</cite>,
1050 * except that underscores are not accepted between digits.
1051 *
1052 * <p>The sequence of characters following an optional
1053 * sign and/or radix specifier ("{@code 0x}", "{@code 0X}",
1054 * "{@code #}", or leading zero) is parsed as by the {@code
1055 * Long.parseLong} method with the indicated radix (10, 16, or 8).
1056 * This sequence of characters must represent a positive value or
1057 * a {@link NumberFormatException} will be thrown. The result is
1058 * negated if first character of the specified {@code String} is
1059 * the minus sign. No whitespace characters are permitted in the
1060 * {@code String}.
1061 *
1062 * @param nm the {@code String} to decode.
1063 * @return a {@code Long} object holding the {@code long}
1064 * value represented by {@code nm}
1065 * @throws NumberFormatException if the {@code String} does not
1066 * contain a parsable {@code long}.
1067 * @see java.lang.Long#parseLong(String, int)
1068 * @since 1.2
1069 */
1070 public static Long decode(String nm) throws NumberFormatException {
1071 int radix = 10;
1072 int index = 0;
1073 boolean negative = false;
1074 long result;
1075
1076 if (nm.isEmpty())
1077 throw new NumberFormatException("Zero length string");
1078 char firstChar = nm.charAt(0);
1079 // Handle sign, if present
1080 if (firstChar == '-') {
1081 negative = true;
1082 index++;
1083 } else if (firstChar == '+')
1084 index++;
1085
1086 // Handle radix specifier, if present
1087 if (nm.startsWith("0x", index) || nm.startsWith("0X", index)) {
1088 index += 2;
1089 radix = 16;
1090 }
1091 else if (nm.startsWith("#", index)) {
1092 index ++;
1093 radix = 16;
1094 }
1095 else if (nm.startsWith("0", index) && nm.length() > 1 + index) {
1096 index ++;
1097 radix = 8;
1098 }
1099
1100 if (nm.startsWith("-", index) || nm.startsWith("+", index))
1101 throw new NumberFormatException("Sign character in wrong position");
1102
1103 try {
1104 result = parseLong(nm, index, nm.length(), radix);
1105 result = negative ? -result : result;
1106 } catch (NumberFormatException e) {
1107 // If number is Long.MIN_VALUE, we'll end up here. The next line
1108 // handles this case, and causes any genuine format error to be
1109 // rethrown.
1110 String constant = negative ? ("-" + nm.substring(index))
1111 : nm.substring(index);
1112 result = parseLong(constant, radix);
1113 }
1114 return result;
1115 }
1116
1117 /**
1118 * The value of the {@code Long}.
1119 *
1120 * @serial
1121 */
1122 private final long value;
1123
1124 /**
1125 * Constructs a newly allocated {@code Long} object that
1126 * represents the specified {@code long} argument.
1127 *
1128 * @param value the value to be represented by the
1129 * {@code Long} object.
1130 *
1131 * @deprecated
1132 * It is rarely appropriate to use this constructor. The static factory
1133 * {@link #valueOf(long)} is generally a better choice, as it is
1134 * likely to yield significantly better space and time performance.
1135 */
1136 @Deprecated(since="9", forRemoval = true)
1137 public Long(long value) {
1138 this.value = value;
1139 }
1140
1141 /**
1142 * Constructs a newly allocated {@code Long} object that
1143 * represents the {@code long} value indicated by the
1144 * {@code String} parameter. The string is converted to a
1145 * {@code long} value in exactly the manner used by the
1146 * {@code parseLong} method for radix 10.
1147 *
1148 * @param s the {@code String} to be converted to a
1149 * {@code Long}.
1150 * @throws NumberFormatException if the {@code String} does not
1151 * contain a parsable {@code long}.
1152 *
1153 * @deprecated
1154 * It is rarely appropriate to use this constructor.
1155 * Use {@link #parseLong(String)} to convert a string to a
1156 * {@code long} primitive, or use {@link #valueOf(String)}
1157 * to convert a string to a {@code Long} object.
1158 */
1159 @Deprecated(since="9", forRemoval = true)
1160 public Long(String s) throws NumberFormatException {
1161 this.value = parseLong(s, 10);
1162 }
1163
1164 /**
1165 * Returns the value of this {@code Long} as a {@code byte} after
1166 * a narrowing primitive conversion.
1167 * @jls 5.1.3 Narrowing Primitive Conversion
1168 */
1169 public byte byteValue() {
1170 return (byte)value;
1171 }
1172
1173 /**
1174 * Returns the value of this {@code Long} as a {@code short} after
1175 * a narrowing primitive conversion.
1176 * @jls 5.1.3 Narrowing Primitive Conversion
1177 */
1178 public short shortValue() {
1179 return (short)value;
1180 }
1181
1182 /**
1183 * Returns the value of this {@code Long} as an {@code int} after
1184 * a narrowing primitive conversion.
1185 * @jls 5.1.3 Narrowing Primitive Conversion
1186 */
1187 public int intValue() {
1188 return (int)value;
1189 }
1190
1191 /**
1192 * Returns the value of this {@code Long} as a
1193 * {@code long} value.
1194 */
1195 @IntrinsicCandidate
1196 public long longValue() {
1197 return value;
1198 }
1199
1200 /**
1201 * Returns the value of this {@code Long} as a {@code float} after
1202 * a widening primitive conversion.
1203 * @jls 5.1.2 Widening Primitive Conversion
1204 */
1205 public float floatValue() {
1206 return (float)value;
1207 }
1208
1209 /**
1210 * Returns the value of this {@code Long} as a {@code double}
1211 * after a widening primitive conversion.
1212 * @jls 5.1.2 Widening Primitive Conversion
1213 */
1214 public double doubleValue() {
1215 return (double)value;
1216 }
1217
1218 /**
1219 * Returns a {@code String} object representing this
1220 * {@code Long}'s value. The value is converted to signed
1221 * decimal representation and returned as a string, exactly as if
1222 * the {@code long} value were given as an argument to the
1223 * {@link java.lang.Long#toString(long)} method.
1224 *
1225 * @return a string representation of the value of this object in
1226 * base 10.
1227 */
1228 public String toString() {
1229 return toString(value);
1230 }
1231
1232 /**
1233 * Returns a hash code for this {@code Long}. The result is
1234 * the exclusive OR of the two halves of the primitive
1235 * {@code long} value held by this {@code Long}
1236 * object. That is, the hashcode is the value of the expression:
1237 *
1238 * <blockquote>
1239 * {@code (int)(this.longValue()^(this.longValue()>>>32))}
1240 * </blockquote>
1241 *
1242 * @return a hash code value for this object.
1243 */
1244 @Override
1245 public int hashCode() {
1246 return Long.hashCode(value);
1247 }
1248
1249 /**
1250 * Returns a hash code for a {@code long} value; compatible with
1251 * {@code Long.hashCode()}.
1252 *
1253 * @param value the value to hash
1254 * @return a hash code value for a {@code long} value.
1255 * @since 1.8
1256 */
1257 public static int hashCode(long value) {
1258 return (int)(value ^ (value >>> 32));
1259 }
1260
1261 /**
1262 * Compares this object to the specified object. The result is
1263 * {@code true} if and only if the argument is not
1264 * {@code null} and is a {@code Long} object that
1265 * contains the same {@code long} value as this object.
1266 *
1267 * @param obj the object to compare with.
1268 * @return {@code true} if the objects are the same;
1269 * {@code false} otherwise.
1270 */
1271 public boolean equals(Object obj) {
1272 if (obj instanceof Long) {
1273 return value == ((Long)obj).longValue();
1274 }
1275 return false;
1276 }
1277
1278 /**
1279 * Determines the {@code long} value of the system property
1280 * with the specified name.
1281 *
1282 * <p>The first argument is treated as the name of a system
1283 * property. System properties are accessible through the {@link
1284 * java.lang.System#getProperty(java.lang.String)} method. The
1285 * string value of this property is then interpreted as a {@code
1286 * long} value using the grammar supported by {@link Long#decode decode}
1287 * and a {@code Long} object representing this value is returned.
1288 *
1289 * <p>If there is no property with the specified name, if the
1290 * specified name is empty or {@code null}, or if the property
1291 * does not have the correct numeric format, then {@code null} is
1292 * returned.
1293 *
1294 * <p>In other words, this method returns a {@code Long} object
1295 * equal to the value of:
1296 *
1297 * <blockquote>
1298 * {@code getLong(nm, null)}
1299 * </blockquote>
1300 *
1301 * @param nm property name.
1302 * @return the {@code Long} value of the property.
1303 * @throws SecurityException for the same reasons as
1304 * {@link System#getProperty(String) System.getProperty}
1305 * @see java.lang.System#getProperty(java.lang.String)
1306 * @see java.lang.System#getProperty(java.lang.String, java.lang.String)
1307 */
1308 public static Long getLong(String nm) {
1309 return getLong(nm, null);
1310 }
1311
1312 /**
1313 * Determines the {@code long} value of the system property
1314 * with the specified name.
1315 *
1316 * <p>The first argument is treated as the name of a system
1317 * property. System properties are accessible through the {@link
1318 * java.lang.System#getProperty(java.lang.String)} method. The
1319 * string value of this property is then interpreted as a {@code
1320 * long} value using the grammar supported by {@link Long#decode decode}
1321 * and a {@code Long} object representing this value is returned.
1322 *
1323 * <p>The second argument is the default value. A {@code Long} object
1324 * that represents the value of the second argument is returned if there
1325 * is no property of the specified name, if the property does not have
1326 * the correct numeric format, or if the specified name is empty or null.
1327 *
1328 * <p>In other words, this method returns a {@code Long} object equal
1329 * to the value of:
1330 *
1331 * <blockquote>
1332 * {@code getLong(nm, Long.valueOf(val))}
1333 * </blockquote>
1334 *
1335 * but in practice it may be implemented in a manner such as:
1336 *
1337 * <blockquote><pre>
1338 * Long result = getLong(nm, null);
1339 * return (result == null) ? Long.valueOf(val) : result;
1340 * </pre></blockquote>
1341 *
1342 * to avoid the unnecessary allocation of a {@code Long} object when
1343 * the default value is not needed.
1344 *
1345 * @param nm property name.
1346 * @param val default value.
1347 * @return the {@code Long} value of the property.
1348 * @throws SecurityException for the same reasons as
1349 * {@link System#getProperty(String) System.getProperty}
1350 * @see java.lang.System#getProperty(java.lang.String)
1351 * @see java.lang.System#getProperty(java.lang.String, java.lang.String)
1352 */
1353 public static Long getLong(String nm, long val) {
1354 Long result = Long.getLong(nm, null);
1355 return (result == null) ? Long.valueOf(val) : result;
1356 }
1357
1358 /**
1359 * Returns the {@code long} value of the system property with
1360 * the specified name. The first argument is treated as the name
1361 * of a system property. System properties are accessible through
1362 * the {@link java.lang.System#getProperty(java.lang.String)}
1363 * method. The string value of this property is then interpreted
1364 * as a {@code long} value, as per the
1365 * {@link Long#decode decode} method, and a {@code Long} object
1366 * representing this value is returned; in summary:
1367 *
1368 * <ul>
1369 * <li>If the property value begins with the two ASCII characters
1370 * {@code 0x} or the ASCII character {@code #}, not followed by
1371 * a minus sign, then the rest of it is parsed as a hexadecimal integer
1372 * exactly as for the method {@link #valueOf(java.lang.String, int)}
1373 * with radix 16.
1374 * <li>If the property value begins with the ASCII character
1375 * {@code 0} followed by another character, it is parsed as
1376 * an octal integer exactly as by the method {@link
1377 * #valueOf(java.lang.String, int)} with radix 8.
1378 * <li>Otherwise the property value is parsed as a decimal
1379 * integer exactly as by the method
1380 * {@link #valueOf(java.lang.String, int)} with radix 10.
1381 * </ul>
1382 *
1383 * <p>Note that, in every case, neither {@code L}
1384 * ({@code '\u005Cu004C'}) nor {@code l}
1385 * ({@code '\u005Cu006C'}) is permitted to appear at the end
1386 * of the property value as a type indicator, as would be
1387 * permitted in Java programming language source code.
1388 *
1389 * <p>The second argument is the default value. The default value is
1390 * returned if there is no property of the specified name, if the
1391 * property does not have the correct numeric format, or if the
1392 * specified name is empty or {@code null}.
1393 *
1394 * @param nm property name.
1395 * @param val default value.
1396 * @return the {@code Long} value of the property.
1397 * @throws SecurityException for the same reasons as
1398 * {@link System#getProperty(String) System.getProperty}
1399 * @see System#getProperty(java.lang.String)
1400 * @see System#getProperty(java.lang.String, java.lang.String)
1401 */
1402 public static Long getLong(String nm, Long val) {
1403 String v = null;
1404 try {
1405 v = System.getProperty(nm);
1406 } catch (IllegalArgumentException | NullPointerException e) {
1407 }
1408 if (v != null) {
1409 try {
1410 return Long.decode(v);
1411 } catch (NumberFormatException e) {
1412 }
1413 }
1414 return val;
1415 }
1416
1417 /**
1418 * Compares two {@code Long} objects numerically.
1419 *
1420 * @param anotherLong the {@code Long} to be compared.
1421 * @return the value {@code 0} if this {@code Long} is
1422 * equal to the argument {@code Long}; a value less than
1423 * {@code 0} if this {@code Long} is numerically less
1424 * than the argument {@code Long}; and a value greater
1425 * than {@code 0} if this {@code Long} is numerically
1426 * greater than the argument {@code Long} (signed
1427 * comparison).
1428 * @since 1.2
1429 */
1430 public int compareTo(Long anotherLong) {
1431 return compare(this.value, anotherLong.value);
1432 }
1433
1434 /**
1435 * Compares two {@code long} values numerically.
1436 * The value returned is identical to what would be returned by:
1437 * <pre>
1438 * Long.valueOf(x).compareTo(Long.valueOf(y))
1439 * </pre>
1440 *
1441 * @param x the first {@code long} to compare
1442 * @param y the second {@code long} to compare
1443 * @return the value {@code 0} if {@code x == y};
1444 * a value less than {@code 0} if {@code x < y}; and
1445 * a value greater than {@code 0} if {@code x > y}
1446 * @since 1.7
1447 */
1448 public static int compare(long x, long y) {
1449 return (x < y) ? -1 : ((x == y) ? 0 : 1);
1450 }
1451
1452 /**
1453 * Compares two {@code long} values numerically treating the values
1454 * as unsigned.
1455 *
1456 * @param x the first {@code long} to compare
1457 * @param y the second {@code long} to compare
1458 * @return the value {@code 0} if {@code x == y}; a value less
1459 * than {@code 0} if {@code x < y} as unsigned values; and
1460 * a value greater than {@code 0} if {@code x > y} as
1461 * unsigned values
1462 * @since 1.8
1463 */
1464 @IntrinsicCandidate
1465 public static int compareUnsigned(long x, long y) {
1466 return compare(x + MIN_VALUE, y + MIN_VALUE);
1467 }
1468
1469
1470 /**
1471 * Returns the unsigned quotient of dividing the first argument by
1472 * the second where each argument and the result is interpreted as
1473 * an unsigned value.
1474 *
1475 * <p>Note that in two's complement arithmetic, the three other
1476 * basic arithmetic operations of add, subtract, and multiply are
1477 * bit-wise identical if the two operands are regarded as both
1478 * being signed or both being unsigned. Therefore separate {@code
1479 * addUnsigned}, etc. methods are not provided.
1480 *
1481 * @param dividend the value to be divided
1482 * @param divisor the value doing the dividing
1483 * @return the unsigned quotient of the first argument divided by
1484 * the second argument
1485 * @see #remainderUnsigned
1486 * @since 1.8
1487 */
1488 @IntrinsicCandidate
1489 public static long divideUnsigned(long dividend, long divisor) {
1490 /* See Hacker's Delight (2nd ed), section 9.3 */
1491 if (divisor >= 0) {
1492 final long q = (dividend >>> 1) / divisor << 1;
1493 final long r = dividend - q * divisor;
1494 return q + ((r | ~(r - divisor)) >>> (Long.SIZE - 1));
1495 }
1496 return (dividend & ~(dividend - divisor)) >>> (Long.SIZE - 1);
1497 }
1498
1499 /**
1500 * Returns the unsigned remainder from dividing the first argument
1501 * by the second where each argument and the result is interpreted
1502 * as an unsigned value.
1503 *
1504 * @param dividend the value to be divided
1505 * @param divisor the value doing the dividing
1506 * @return the unsigned remainder of the first argument divided by
1507 * the second argument
1508 * @see #divideUnsigned
1509 * @since 1.8
1510 */
1511 @IntrinsicCandidate
1512 public static long remainderUnsigned(long dividend, long divisor) {
1513 /* See Hacker's Delight (2nd ed), section 9.3 */
1514 if (divisor >= 0) {
1515 final long q = (dividend >>> 1) / divisor << 1;
1516 final long r = dividend - q * divisor;
1517 /*
1518 * Here, 0 <= r < 2 * divisor
1519 * (1) When 0 <= r < divisor, the remainder is simply r.
1520 * (2) Otherwise the remainder is r - divisor.
1521 *
1522 * In case (1), r - divisor < 0. Applying ~ produces a long with
1523 * sign bit 0, so >> produces 0. The returned value is thus r.
1524 *
1525 * In case (2), a similar reasoning shows that >> produces -1,
1526 * so the returned value is r - divisor.
1527 */
1528 return r - ((~(r - divisor) >> (Long.SIZE - 1)) & divisor);
1529 }
1530 /*
1531 * (1) When dividend >= 0, the remainder is dividend.
1532 * (2) Otherwise
1533 * (2.1) When dividend < divisor, the remainder is dividend.
1534 * (2.2) Otherwise the remainder is dividend - divisor
1535 *
1536 * A reasoning similar to the above shows that the returned value
1537 * is as expected.
1538 */
1539 return dividend - (((dividend & ~(dividend - divisor)) >> (Long.SIZE - 1)) & divisor);
1540 }
1541
1542 // Bit Twiddling
1543
1544 /**
1545 * The number of bits used to represent a {@code long} value in two's
1546 * complement binary form.
1547 *
1548 * @since 1.5
1549 */
1550 @Native public static final int SIZE = 64;
1551
1552 /**
1553 * The number of bytes used to represent a {@code long} value in two's
1554 * complement binary form.
1555 *
1556 * @since 1.8
1557 */
1558 public static final int BYTES = SIZE / Byte.SIZE;
1559
1560 /**
1561 * Returns a {@code long} value with at most a single one-bit, in the
1562 * position of the highest-order ("leftmost") one-bit in the specified
1563 * {@code long} value. Returns zero if the specified value has no
1564 * one-bits in its two's complement binary representation, that is, if it
1565 * is equal to zero.
1566 *
1567 * @param i the value whose highest one bit is to be computed
1568 * @return a {@code long} value with a single one-bit, in the position
1569 * of the highest-order one-bit in the specified value, or zero if
1570 * the specified value is itself equal to zero.
1571 * @since 1.5
1572 */
1573 public static long highestOneBit(long i) {
1574 return i & (MIN_VALUE >>> numberOfLeadingZeros(i));
1575 }
1576
1577 /**
1578 * Returns a {@code long} value with at most a single one-bit, in the
1579 * position of the lowest-order ("rightmost") one-bit in the specified
1580 * {@code long} value. Returns zero if the specified value has no
1581 * one-bits in its two's complement binary representation, that is, if it
1582 * is equal to zero.
1583 *
1584 * @param i the value whose lowest one bit is to be computed
1585 * @return a {@code long} value with a single one-bit, in the position
1586 * of the lowest-order one-bit in the specified value, or zero if
1587 * the specified value is itself equal to zero.
1588 * @since 1.5
1589 */
1590 public static long lowestOneBit(long i) {
1591 // HD, Section 2-1
1592 return i & -i;
1593 }
1594
1595 /**
1596 * Returns the number of zero bits preceding the highest-order
1597 * ("leftmost") one-bit in the two's complement binary representation
1598 * of the specified {@code long} value. Returns 64 if the
1599 * specified value has no one-bits in its two's complement representation,
1600 * in other words if it is equal to zero.
1601 *
1602 * <p>Note that this method is closely related to the logarithm base 2.
1603 * For all positive {@code long} values x:
1604 * <ul>
1605 * <li>floor(log<sub>2</sub>(x)) = {@code 63 - numberOfLeadingZeros(x)}
1606 * <li>ceil(log<sub>2</sub>(x)) = {@code 64 - numberOfLeadingZeros(x - 1)}
1607 * </ul>
1608 *
1609 * @param i the value whose number of leading zeros is to be computed
1610 * @return the number of zero bits preceding the highest-order
1611 * ("leftmost") one-bit in the two's complement binary representation
1612 * of the specified {@code long} value, or 64 if the value
1613 * is equal to zero.
1614 * @since 1.5
1615 */
1616 @IntrinsicCandidate
1617 public static int numberOfLeadingZeros(long i) {
1618 int x = (int)(i >>> 32);
1619 return x == 0 ? 32 + Integer.numberOfLeadingZeros((int)i)
1620 : Integer.numberOfLeadingZeros(x);
1621 }
1622
1623 /**
1624 * Returns the number of zero bits following the lowest-order ("rightmost")
1625 * one-bit in the two's complement binary representation of the specified
1626 * {@code long} value. Returns 64 if the specified value has no
1627 * one-bits in its two's complement representation, in other words if it is
1628 * equal to zero.
1629 *
1630 * @param i the value whose number of trailing zeros is to be computed
1631 * @return the number of zero bits following the lowest-order ("rightmost")
1632 * one-bit in the two's complement binary representation of the
1633 * specified {@code long} value, or 64 if the value is equal
1634 * to zero.
1635 * @since 1.5
1636 */
1637 @IntrinsicCandidate
1638 public static int numberOfTrailingZeros(long i) {
1639 int x = (int)i;
1640 return x == 0 ? 32 + Integer.numberOfTrailingZeros((int)(i >>> 32))
1641 : Integer.numberOfTrailingZeros(x);
1642 }
1643
1644 /**
1645 * Returns the number of one-bits in the two's complement binary
1646 * representation of the specified {@code long} value. This function is
1647 * sometimes referred to as the <i>population count</i>.
1648 *
1649 * @param i the value whose bits are to be counted
1650 * @return the number of one-bits in the two's complement binary
1651 * representation of the specified {@code long} value.
1652 * @since 1.5
1653 */
1654 @IntrinsicCandidate
1655 public static int bitCount(long i) {
1656 // HD, Figure 5-2
1657 i = i - ((i >>> 1) & 0x5555555555555555L);
1658 i = (i & 0x3333333333333333L) + ((i >>> 2) & 0x3333333333333333L);
1659 i = (i + (i >>> 4)) & 0x0f0f0f0f0f0f0f0fL;
1660 i = i + (i >>> 8);
1661 i = i + (i >>> 16);
1662 i = i + (i >>> 32);
1663 return (int)i & 0x7f;
1664 }
1665
1666 /**
1667 * Returns the value obtained by rotating the two's complement binary
1668 * representation of the specified {@code long} value left by the
1669 * specified number of bits. (Bits shifted out of the left hand, or
1670 * high-order, side reenter on the right, or low-order.)
1671 *
1672 * <p>Note that left rotation with a negative distance is equivalent to
1673 * right rotation: {@code rotateLeft(val, -distance) == rotateRight(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 rotateLeft(val,
1677 * distance) == rotateLeft(val, distance & 0x3F)}.
1678 *
1679 * @param i the value whose bits are to be rotated left
1680 * @param distance the number of bit positions to rotate left
1681 * @return the value obtained by rotating the two's complement binary
1682 * representation of the specified {@code long} value left by the
1683 * specified number of bits.
1684 * @since 1.5
1685 */
1686 public static long rotateLeft(long i, int distance) {
1687 return (i << distance) | (i >>> -distance);
1688 }
1689
1690 /**
1691 * Returns the value obtained by rotating the two's complement binary
1692 * representation of the specified {@code long} value right by the
1693 * specified number of bits. (Bits shifted out of the right hand, or
1694 * low-order, side reenter on the left, or high-order.)
1695 *
1696 * <p>Note that right rotation with a negative distance is equivalent to
1697 * left rotation: {@code rotateRight(val, -distance) == rotateLeft(val,
1698 * distance)}. Note also that rotation by any multiple of 64 is a
1699 * no-op, so all but the last six bits of the rotation distance can be
1700 * ignored, even if the distance is negative: {@code rotateRight(val,
1701 * distance) == rotateRight(val, distance & 0x3F)}.
1702 *
1703 * @param i the value whose bits are to be rotated right
1704 * @param distance the number of bit positions to rotate right
1705 * @return the value obtained by rotating the two's complement binary
1706 * representation of the specified {@code long} value right by the
1707 * specified number of bits.
1708 * @since 1.5
1709 */
1710 public static long rotateRight(long i, int distance) {
1711 return (i >>> distance) | (i << -distance);
1712 }
1713
1714 /**
1715 * Returns the value obtained by reversing the order of the bits in the
1716 * two's complement binary representation of the specified {@code long}
1717 * value.
1718 *
1719 * @param i the value to be reversed
1720 * @return the value obtained by reversing order of the bits in the
1721 * specified {@code long} value.
1722 * @since 1.5
1723 */
1724 @IntrinsicCandidate
1725 public static long reverse(long i) {
1726 // HD, Figure 7-1
1727 i = (i & 0x5555555555555555L) << 1 | (i >>> 1) & 0x5555555555555555L;
1728 i = (i & 0x3333333333333333L) << 2 | (i >>> 2) & 0x3333333333333333L;
1729 i = (i & 0x0f0f0f0f0f0f0f0fL) << 4 | (i >>> 4) & 0x0f0f0f0f0f0f0f0fL;
1730
1731 return reverseBytes(i);
1732 }
1733
1734 /**
1735 * Returns the value obtained by compressing the bits of the
1736 * specified {@code long} value, {@code i}, in accordance with
1737 * the specified bit mask.
1738 * <p>
1739 * For each one-bit value {@code mb} of the mask, from least
1740 * significant to most significant, the bit value of {@code i} at
1741 * the same bit location as {@code mb} is assigned to the compressed
1742 * value contiguously starting from the least significant bit location.
1743 * All the upper remaining bits of the compressed value are set
1744 * to zero.
1745 *
1746 * @apiNote
1747 * Consider the simple case of compressing the digits of a hexadecimal
1748 * value:
1749 * {@snippet lang="java" :
1750 * // Compressing drink to food
1751 * compress(0xCAFEBABEL, 0xFF00FFF0L) == 0xCABABL
1752 * }
1753 * Starting from the least significant hexadecimal digit at position 0
1754 * from the right, the mask {@code 0xFF00FFF0} selects hexadecimal digits
1755 * at positions 1, 2, 3, 6 and 7 of {@code 0xCAFEBABE}. The selected digits
1756 * occur in the resulting compressed value contiguously from digit position
1757 * 0 in the same order.
1758 * <p>
1759 * The following identities all return {@code true} and are helpful to
1760 * understand the behaviour of {@code compress}:
1761 * {@snippet lang="java" :
1762 * // Returns 1 if the bit at position n is one
1763 * compress(x, 1L << n) == (x >> n & 1)
1764 *
1765 * // Logical shift right
1766 * compress(x, -1L << n) == x >>> n
1767 *
1768 * // Any bits not covered by the mask are ignored
1769 * compress(x, m) == compress(x & m, m)
1770 *
1771 * // Compressing a value by itself
1772 * compress(m, m) == (m == -1 || m == 0) ? m : (1L << bitCount(m)) - 1
1773 *
1774 * // Expanding then compressing with the same mask
1775 * compress(expand(x, m), m) == x & compress(m, m)
1776 * }
1777 * <p>
1778 * The Sheep And Goats (SAG) operation (see Hacker's Delight, section 7.7)
1779 * can be implemented as follows:
1780 * {@snippet lang="java" :
1781 * long compressLeft(long i, long mask) {
1782 * // This implementation follows the description in Hacker's Delight which
1783 * // is informative. A more optimal implementation is:
1784 * // Long.compress(i, mask) << -Long.bitCount(mask)
1785 * return Long.reverse(
1786 * Long.compress(Long.reverse(i), Long.reverse(mask)));
1787 * }
1788 *
1789 * long sag(long i, long mask) {
1790 * return compressLeft(i, mask) | Long.compress(i, ~mask);
1791 * }
1792 *
1793 * // Separate the sheep from the goats
1794 * sag(0x00000000_CAFEBABEL, 0xFFFFFFFF_FF00FFF0L) == 0x00000000_CABABFEEL
1795 * }
1796 *
1797 * @param i the value whose bits are to be compressed
1798 * @param mask the bit mask
1799 * @return the compressed value
1800 * @see #expand
1801 * @since 19
1802 */
1803 @IntrinsicCandidate
1804 public static long compress(long i, long mask) {
1805 // See Hacker's Delight (2nd ed) section 7.4 Compress, or Generalized Extract
1806
1807 i = i & mask; // Clear irrelevant bits
1808 long maskCount = ~mask << 1; // Count 0's to right
1809
1810 for (int j = 0; j < 6; j++) {
1811 // Parallel prefix
1812 // Mask prefix identifies bits of the mask that have an odd number of 0's to the right
1813 long maskPrefix = parallelSuffix(maskCount);
1814 // Bits to move
1815 long maskMove = maskPrefix & mask;
1816 // Compress mask
1817 mask = (mask ^ maskMove) | (maskMove >>> (1 << j));
1818 // Bits of i to be moved
1819 long t = i & maskMove;
1820 // Compress i
1821 i = (i ^ t) | (t >>> (1 << j));
1822 // Adjust the mask count by identifying bits that have 0 to the right
1823 maskCount = maskCount & ~maskPrefix;
1824 }
1825 return i;
1826 }
1827
1828 /**
1829 * Returns the value obtained by expanding the bits of the
1830 * specified {@code long} value, {@code i}, in accordance with
1831 * the specified bit mask.
1832 * <p>
1833 * For each one-bit value {@code mb} of the mask, from least
1834 * significant to most significant, the next contiguous bit value
1835 * of {@code i} starting at the least significant bit is assigned
1836 * to the expanded value at the same bit location as {@code mb}.
1837 * All other remaining bits of the expanded value are set to zero.
1838 *
1839 * @apiNote
1840 * Consider the simple case of expanding the digits of a hexadecimal
1841 * value:
1842 * {@snippet lang="java" :
1843 * expand(0x0000CABABL, 0xFF00FFF0L) == 0xCA00BAB0L
1844 * }
1845 * Starting from the least significant hexadecimal digit at position 0
1846 * from the right, the mask {@code 0xFF00FFF0} selects the first five
1847 * hexadecimal digits of {@code 0x0000CABAB}. The selected digits occur
1848 * in the resulting expanded value in order at positions 1, 2, 3, 6, and 7.
1849 * <p>
1850 * The following identities all return {@code true} and are helpful to
1851 * understand the behaviour of {@code expand}:
1852 * {@snippet lang="java" :
1853 * // Logically shift right the bit at position 0
1854 * expand(x, 1L << n) == (x & 1) << n
1855 *
1856 * // Logically shift right
1857 * expand(x, -1L << n) == x << n
1858 *
1859 * // Expanding all bits returns the mask
1860 * expand(-1L, m) == m
1861 *
1862 * // Any bits not covered by the mask are ignored
1863 * expand(x, m) == expand(x, m) & m
1864 *
1865 * // Compressing then expanding with the same mask
1866 * expand(compress(x, m), m) == x & m
1867 * }
1868 * <p>
1869 * The select operation for determining the position of the one-bit with
1870 * index {@code n} in a {@code long} value can be implemented as follows:
1871 * {@snippet lang="java" :
1872 * long select(long i, long n) {
1873 * // the one-bit in i (the mask) with index n
1874 * long nthBit = Long.expand(1L << n, i);
1875 * // the bit position of the one-bit with index n
1876 * return Long.numberOfTrailingZeros(nthBit);
1877 * }
1878 *
1879 * // The one-bit with index 0 is at bit position 1
1880 * select(0b10101010_10101010, 0) == 1
1881 * // The one-bit with index 3 is at bit position 7
1882 * select(0b10101010_10101010, 3) == 7
1883 * }
1884 *
1885 * @param i the value whose bits are to be expanded
1886 * @param mask the bit mask
1887 * @return the expanded value
1888 * @see #compress
1889 * @since 19
1890 */
1891 @IntrinsicCandidate
1892 public static long expand(long i, long mask) {
1893 // Save original mask
1894 long originalMask = mask;
1895 // Count 0's to right
1896 long maskCount = ~mask << 1;
1897 long maskPrefix = parallelSuffix(maskCount);
1898 // Bits to move
1899 long maskMove1 = maskPrefix & mask;
1900 // Compress mask
1901 mask = (mask ^ maskMove1) | (maskMove1 >>> (1 << 0));
1902 maskCount = maskCount & ~maskPrefix;
1903
1904 maskPrefix = parallelSuffix(maskCount);
1905 // Bits to move
1906 long maskMove2 = maskPrefix & mask;
1907 // Compress mask
1908 mask = (mask ^ maskMove2) | (maskMove2 >>> (1 << 1));
1909 maskCount = maskCount & ~maskPrefix;
1910
1911 maskPrefix = parallelSuffix(maskCount);
1912 // Bits to move
1913 long maskMove3 = maskPrefix & mask;
1914 // Compress mask
1915 mask = (mask ^ maskMove3) | (maskMove3 >>> (1 << 2));
1916 maskCount = maskCount & ~maskPrefix;
1917
1918 maskPrefix = parallelSuffix(maskCount);
1919 // Bits to move
1920 long maskMove4 = maskPrefix & mask;
1921 // Compress mask
1922 mask = (mask ^ maskMove4) | (maskMove4 >>> (1 << 3));
1923 maskCount = maskCount & ~maskPrefix;
1924
1925 maskPrefix = parallelSuffix(maskCount);
1926 // Bits to move
1927 long maskMove5 = maskPrefix & mask;
1928 // Compress mask
1929 mask = (mask ^ maskMove5) | (maskMove5 >>> (1 << 4));
1930 maskCount = maskCount & ~maskPrefix;
1931
1932 maskPrefix = parallelSuffix(maskCount);
1933 // Bits to move
1934 long maskMove6 = maskPrefix & mask;
1935
1936 long t = i << (1 << 5);
1937 i = (i & ~maskMove6) | (t & maskMove6);
1938 t = i << (1 << 4);
1939 i = (i & ~maskMove5) | (t & maskMove5);
1940 t = i << (1 << 3);
1941 i = (i & ~maskMove4) | (t & maskMove4);
1942 t = i << (1 << 2);
1943 i = (i & ~maskMove3) | (t & maskMove3);
1944 t = i << (1 << 1);
1945 i = (i & ~maskMove2) | (t & maskMove2);
1946 t = i << (1 << 0);
1947 i = (i & ~maskMove1) | (t & maskMove1);
1948
1949 // Clear irrelevant bits
1950 return i & originalMask;
1951 }
1952
1953 @ForceInline
1954 private static long parallelSuffix(long maskCount) {
1955 long maskPrefix = maskCount ^ (maskCount << 1);
1956 maskPrefix = maskPrefix ^ (maskPrefix << 2);
1957 maskPrefix = maskPrefix ^ (maskPrefix << 4);
1958 maskPrefix = maskPrefix ^ (maskPrefix << 8);
1959 maskPrefix = maskPrefix ^ (maskPrefix << 16);
1960 maskPrefix = maskPrefix ^ (maskPrefix << 32);
1961 return maskPrefix;
1962 }
1963
1964 /**
1965 * Returns the signum function of the specified {@code long} value. (The
1966 * return value is -1 if the specified value is negative; 0 if the
1967 * specified value is zero; and 1 if the specified value is positive.)
1968 *
1969 * @param i the value whose signum is to be computed
1970 * @return the signum function of the specified {@code long} value.
1971 * @since 1.5
1972 */
1973 public static int signum(long i) {
1974 // HD, Section 2-7
1975 return (int) ((i >> 63) | (-i >>> 63));
1976 }
1977
1978 /**
1979 * Returns the value obtained by reversing the order of the bytes in the
1980 * two's complement representation of the specified {@code long} value.
1981 *
1982 * @param i the value whose bytes are to be reversed
1983 * @return the value obtained by reversing the bytes in the specified
1984 * {@code long} value.
1985 * @since 1.5
1986 */
1987 @IntrinsicCandidate
1988 public static long reverseBytes(long i) {
1989 i = (i & 0x00ff00ff00ff00ffL) << 8 | (i >>> 8) & 0x00ff00ff00ff00ffL;
1990 return (i << 48) | ((i & 0xffff0000L) << 16) |
1991 ((i >>> 16) & 0xffff0000L) | (i >>> 48);
1992 }
1993
1994 /**
1995 * Adds two {@code long} values together as per the + operator.
1996 *
1997 * @param a the first operand
1998 * @param b the second operand
1999 * @return the sum of {@code a} and {@code b}
2000 * @see java.util.function.BinaryOperator
2001 * @since 1.8
2002 */
2003 public static long sum(long a, long b) {
2004 return a + b;
2005 }
2006
2007 /**
2008 * Returns the greater of two {@code long} values
2009 * as if by calling {@link Math#max(long, long) Math.max}.
2010 *
2011 * @param a the first operand
2012 * @param b the second operand
2013 * @return the greater of {@code a} and {@code b}
2014 * @see java.util.function.BinaryOperator
2015 * @since 1.8
2016 */
2017 public static long max(long a, long b) {
2018 return Math.max(a, b);
2019 }
2020
2021 /**
2022 * Returns the smaller of two {@code long} values
2023 * as if by calling {@link Math#min(long, long) Math.min}.
2024 *
2025 * @param a the first operand
2026 * @param b the second operand
2027 * @return the smaller of {@code a} and {@code b}
2028 * @see java.util.function.BinaryOperator
2029 * @since 1.8
2030 */
2031 public static long min(long a, long b) {
2032 return Math.min(a, b);
2033 }
2034
2035 /**
2036 * Returns an {@link Optional} containing the nominal descriptor for this
2037 * instance, which is the instance itself.
2038 *
2039 * @return an {@link Optional} describing the {@linkplain Long} instance
2040 * @since 12
2041 */
2042 @Override
2043 public Optional<Long> describeConstable() {
2044 return Optional.of(this);
2045 }
2046
2047 /**
2048 * Resolves this instance as a {@link ConstantDesc}, the result of which is
2049 * the instance itself.
2050 *
2051 * @param lookup ignored
2052 * @return the {@linkplain Long} instance
2053 * @since 12
2054 */
2055 @Override
2056 public Long resolveConstantDesc(MethodHandles.Lookup lookup) {
2057 return this;
2058 }
2059
2060 /** use serialVersionUID from JDK 1.0.2 for interoperability */
2061 @java.io.Serial
2062 @Native private static final long serialVersionUID = 4290774380558885855L;
2063 }