1 /*
2 * Copyright (c) 1994, 2013, 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.math.*;
30 import java.util.Objects;
31 import jdk.internal.HotSpotIntrinsicCandidate;
32
33 import static java.lang.String.COMPACT_STRINGS;
34 import static java.lang.String.LATIN1;
35 import static java.lang.String.UTF16;
36
37 /**
38 * The {@code Long} class wraps a value of the primitive type {@code
39 * long} in an object. An object of type {@code Long} contains a
40 * single field whose type is {@code long}.
41 *
42 * <p> In addition, this class provides several methods for converting
43 * a {@code long} to a {@code String} and a {@code String} to a {@code
44 * long}, as well as other constants and methods useful when dealing
45 * with a {@code long}.
46 *
47 * <p>Implementation note: The implementations of the "bit twiddling"
48 * methods (such as {@link #highestOneBit(long) highestOneBit} and
49 * {@link #numberOfTrailingZeros(long) numberOfTrailingZeros}) are
50 * based on material from Henry S. Warren, Jr.'s <i>Hacker's
51 * Delight</i>, (Addison Wesley, 2002).
52 *
53 * @author Lee Boynton
54 * @author Arthur van Hoff
55 * @author Josh Bloch
56 * @author Joseph D. Darcy
57 * @since 1.0
58 */
59 public final class Long extends Number implements Comparable<Long> {
60 /**
61 * A constant holding the minimum value a {@code long} can
62 * have, -2<sup>63</sup>.
63 */
64 @Native public static final long MIN_VALUE = 0x8000000000000000L;
65
66 /**
67 * A constant holding the maximum value a {@code long} can
68 * have, 2<sup>63</sup>-1.
69 */
70 @Native public static final long MAX_VALUE = 0x7fffffffffffffffL;
71
72 /**
73 * The {@code Class} instance representing the primitive type
74 * {@code long}.
75 *
76 * @since 1.1
77 */
78 @SuppressWarnings("unchecked")
79 public static final Class<Long> TYPE = (Class<Long>) Class.getPrimitiveClass("long");
80
81 /**
82 * Returns a string representation of the first argument in the
83 * radix specified by the second argument.
84 *
85 * <p>If the radix is smaller than {@code Character.MIN_RADIX}
86 * or larger than {@code Character.MAX_RADIX}, then the radix
87 * {@code 10} is used instead.
88 *
89 * <p>If the first argument is negative, the first element of the
90 * result is the ASCII minus sign {@code '-'}
91 * ({@code '\u005Cu002d'}). If the first argument is not
92 * negative, no sign character appears in the result.
93 *
94 * <p>The remaining characters of the result represent the magnitude
95 * of the first argument. If the magnitude is zero, it is
96 * represented by a single zero character {@code '0'}
97 * ({@code '\u005Cu0030'}); otherwise, the first character of
98 * the representation of the magnitude will not be the zero
99 * character. The following ASCII characters are used as digits:
100 *
101 * <blockquote>
102 * {@code 0123456789abcdefghijklmnopqrstuvwxyz}
103 * </blockquote>
104 *
105 * These are {@code '\u005Cu0030'} through
106 * {@code '\u005Cu0039'} and {@code '\u005Cu0061'} through
107 * {@code '\u005Cu007a'}. If {@code radix} is
108 * <var>N</var>, then the first <var>N</var> of these characters
109 * are used as radix-<var>N</var> digits in the order shown. Thus,
110 * the digits for hexadecimal (radix 16) are
111 * {@code 0123456789abcdef}. If uppercase letters are
112 * desired, the {@link java.lang.String#toUpperCase()} method may
113 * be called on the result:
114 *
115 * <blockquote>
116 * {@code Long.toString(n, 16).toUpperCase()}
117 * </blockquote>
118 *
119 * @param i a {@code long} to be converted to a string.
120 * @param radix the radix to use in the string representation.
121 * @return a string representation of the argument in the specified radix.
122 * @see java.lang.Character#MAX_RADIX
123 * @see java.lang.Character#MIN_RADIX
124 */
125 public static String toString(long i, int radix) {
126 if (radix < Character.MIN_RADIX || radix > Character.MAX_RADIX)
127 radix = 10;
128 if (radix == 10)
129 return toString(i);
130
131 if (COMPACT_STRINGS) {
132 byte[] buf = new byte[65];
133 int charPos = 64;
134 boolean negative = (i < 0);
135
136 if (!negative) {
137 i = -i;
138 }
139
140 while (i <= -radix) {
141 buf[charPos--] = (byte)Integer.digits[(int)(-(i % radix))];
142 i = i / radix;
143 }
144 buf[charPos] = (byte)Integer.digits[(int)(-i)];
145
146 if (negative) {
147 buf[--charPos] = '-';
148 }
149 return StringLatin1.newString(buf, charPos, (65 - charPos));
150 }
151 return toStringUTF16(i, radix);
152 }
153
154 private static String toStringUTF16(long i, int radix) {
155 byte[] buf = new byte[65 * 2];
156 int charPos = 64;
157 boolean negative = (i < 0);
158 if (!negative) {
159 i = -i;
160 }
161 while (i <= -radix) {
162 StringUTF16.putChar(buf, charPos--, Integer.digits[(int)(-(i % radix))]);
163 i = i / radix;
164 }
165 StringUTF16.putChar(buf, charPos, Integer.digits[(int)(-i)]);
166 if (negative) {
167 StringUTF16.putChar(buf, --charPos, '-');
168 }
169 return StringUTF16.newString(buf, charPos, (65 - charPos));
170 }
171
172 /**
173 * Returns a string representation of the first argument as an
174 * unsigned integer value in the radix specified by the second
175 * argument.
176 *
177 * <p>If the radix is smaller than {@code Character.MIN_RADIX}
178 * or larger than {@code Character.MAX_RADIX}, then the radix
179 * {@code 10} is used instead.
180 *
181 * <p>Note that since the first argument is treated as an unsigned
182 * value, no leading sign character is printed.
183 *
184 * <p>If the magnitude is zero, it is represented by a single zero
185 * character {@code '0'} ({@code '\u005Cu0030'}); otherwise,
186 * the first character of the representation of the magnitude will
187 * not be the zero character.
188 *
189 * <p>The behavior of radixes and the characters used as digits
190 * are the same as {@link #toString(long, int) toString}.
191 *
192 * @param i an integer to be converted to an unsigned string.
193 * @param radix the radix to use in the string representation.
194 * @return an unsigned string representation of the argument in the specified radix.
195 * @see #toString(long, int)
196 * @since 1.8
197 */
198 public static String toUnsignedString(long i, int radix) {
199 if (i >= 0)
200 return toString(i, radix);
201 else {
202 switch (radix) {
203 case 2:
204 return toBinaryString(i);
205
206 case 4:
207 return toUnsignedString0(i, 2);
208
209 case 8:
210 return toOctalString(i);
211
212 case 10:
213 /*
214 * We can get the effect of an unsigned division by 10
215 * on a long value by first shifting right, yielding a
216 * positive value, and then dividing by 5. This
217 * allows the last digit and preceding digits to be
218 * isolated more quickly than by an initial conversion
219 * to BigInteger.
220 */
221 long quot = (i >>> 1) / 5;
222 long rem = i - quot * 10;
223 return toString(quot) + rem;
224
225 case 16:
226 return toHexString(i);
227
228 case 32:
229 return toUnsignedString0(i, 5);
230
231 default:
232 return toUnsignedBigInteger(i).toString(radix);
233 }
234 }
235 }
236
237 /**
238 * Return a BigInteger equal to the unsigned value of the
239 * argument.
240 */
241 private static BigInteger toUnsignedBigInteger(long i) {
242 if (i >= 0L)
243 return BigInteger.valueOf(i);
244 else {
245 int upper = (int) (i >>> 32);
246 int lower = (int) i;
247
248 // return (upper << 32) + lower
249 return (BigInteger.valueOf(Integer.toUnsignedLong(upper))).shiftLeft(32).
250 add(BigInteger.valueOf(Integer.toUnsignedLong(lower)));
251 }
252 }
253
254 /**
255 * Returns a string representation of the {@code long}
256 * argument as an unsigned integer in base 16.
257 *
258 * <p>The unsigned {@code long} value is the argument plus
259 * 2<sup>64</sup> if the argument is negative; otherwise, it is
260 * equal to the argument. This value is converted to a string of
261 * ASCII digits in hexadecimal (base 16) with no extra
262 * leading {@code 0}s.
263 *
264 * <p>The value of the argument can be recovered from the returned
265 * string {@code s} by calling {@link
266 * Long#parseUnsignedLong(String, int) Long.parseUnsignedLong(s,
267 * 16)}.
268 *
269 * <p>If the unsigned magnitude is zero, it is represented by a
270 * single zero character {@code '0'} ({@code '\u005Cu0030'});
271 * otherwise, the first character of the representation of the
272 * unsigned magnitude will not be the zero character. The
273 * following characters are used as hexadecimal digits:
274 *
275 * <blockquote>
276 * {@code 0123456789abcdef}
277 * </blockquote>
278 *
279 * These are the characters {@code '\u005Cu0030'} through
280 * {@code '\u005Cu0039'} and {@code '\u005Cu0061'} through
281 * {@code '\u005Cu0066'}. If uppercase letters are desired,
282 * the {@link java.lang.String#toUpperCase()} method may be called
283 * on the result:
284 *
285 * <blockquote>
286 * {@code Long.toHexString(n).toUpperCase()}
287 * </blockquote>
288 *
289 * @param i a {@code long} to be converted to a string.
290 * @return the string representation of the unsigned {@code long}
291 * value represented by the argument in hexadecimal
292 * (base 16).
293 * @see #parseUnsignedLong(String, int)
294 * @see #toUnsignedString(long, int)
295 * @since 1.0.2
296 */
297 public static String toHexString(long i) {
298 return toUnsignedString0(i, 4);
299 }
300
301 /**
302 * Returns a string representation of the {@code long}
303 * argument as an unsigned integer in base 8.
304 *
305 * <p>The unsigned {@code long} value is the argument plus
306 * 2<sup>64</sup> if the argument is negative; otherwise, it is
307 * equal to the argument. This value is converted to a string of
308 * ASCII digits in octal (base 8) with no extra leading
309 * {@code 0}s.
310 *
311 * <p>The value of the argument can be recovered from the returned
312 * string {@code s} by calling {@link
313 * Long#parseUnsignedLong(String, int) Long.parseUnsignedLong(s,
314 * 8)}.
315 *
316 * <p>If the unsigned magnitude is zero, it is represented by a
317 * single zero character {@code '0'} ({@code '\u005Cu0030'});
318 * otherwise, the first character of the representation of the
319 * unsigned magnitude will not be the zero character. The
320 * following characters are used as octal digits:
321 *
322 * <blockquote>
323 * {@code 01234567}
324 * </blockquote>
325 *
326 * These are the characters {@code '\u005Cu0030'} through
327 * {@code '\u005Cu0037'}.
328 *
329 * @param i a {@code long} to be converted to a string.
330 * @return the string representation of the unsigned {@code long}
331 * value represented by the argument in octal (base 8).
332 * @see #parseUnsignedLong(String, int)
333 * @see #toUnsignedString(long, int)
334 * @since 1.0.2
335 */
336 public static String toOctalString(long i) {
337 return toUnsignedString0(i, 3);
338 }
339
340 /**
341 * Returns a string representation of the {@code long}
342 * argument as an unsigned integer in base 2.
343 *
344 * <p>The unsigned {@code long} value is the argument plus
345 * 2<sup>64</sup> if the argument is negative; otherwise, it is
346 * equal to the argument. This value is converted to a string of
347 * ASCII digits in binary (base 2) with no extra leading
348 * {@code 0}s.
349 *
350 * <p>The value of the argument can be recovered from the returned
351 * string {@code s} by calling {@link
352 * Long#parseUnsignedLong(String, int) Long.parseUnsignedLong(s,
353 * 2)}.
354 *
355 * <p>If the unsigned magnitude is zero, it is represented by a
356 * single zero character {@code '0'} ({@code '\u005Cu0030'});
357 * otherwise, the first character of the representation of the
358 * unsigned magnitude will not be the zero character. The
359 * characters {@code '0'} ({@code '\u005Cu0030'}) and {@code
360 * '1'} ({@code '\u005Cu0031'}) are used as binary digits.
361 *
362 * @param i a {@code long} to be converted to a string.
363 * @return the string representation of the unsigned {@code long}
364 * value represented by the argument in binary (base 2).
365 * @see #parseUnsignedLong(String, int)
366 * @see #toUnsignedString(long, int)
367 * @since 1.0.2
368 */
369 public static String toBinaryString(long i) {
370 return toUnsignedString0(i, 1);
371 }
372
373 /**
374 * Format a long (treated as unsigned) into a String.
375 * @param val the value to format
376 * @param shift the log2 of the base to format in (4 for hex, 3 for octal, 1 for binary)
377 */
378 static String toUnsignedString0(long val, int shift) {
379 // assert shift > 0 && shift <=5 : "Illegal shift value";
380 int mag = Long.SIZE - Long.numberOfLeadingZeros(val);
381 int chars = Math.max(((mag + (shift - 1)) / shift), 1);
382
383 if (COMPACT_STRINGS) {
384 byte[] buf = new byte[chars];
385 formatUnsignedLong0(val, shift, buf, 0, chars);
386 return new String(buf, LATIN1);
387 } else {
388 byte[] buf = new byte[chars * 2];
389 formatUnsignedLong0UTF16(val, shift, buf, 0, chars);
390 return new String(buf, UTF16);
391 }
392 }
393
394 /**
395 * Format a long (treated as unsigned) into a character buffer. If
396 * {@code len} exceeds the formatted ASCII representation of {@code val},
397 * {@code buf} will be padded with leading zeroes.
398 *
399 * @param val the unsigned long to format
400 * @param shift the log2 of the base to format in (4 for hex, 3 for octal, 1 for binary)
401 * @param buf the character buffer to write to
402 * @param offset the offset in the destination buffer to start at
403 * @param len the number of characters to write
404 */
405 static void formatUnsignedLong(long val, int shift, char[] buf, int offset, int len) {
406 // assert shift > 0 && shift <=5 : "Illegal shift value";
407 // assert offset >= 0 && offset < buf.length : "illegal offset";
408 // assert len > 0 && (offset + len) <= buf.length : "illegal length";
409 int charPos = offset + len;
410 int radix = 1 << shift;
411 int mask = radix - 1;
412 do {
413 buf[--charPos] = Integer.digits[((int) val) & mask];
414 val >>>= shift;
415 } while (charPos > offset);
416 }
417
418 /** byte[]/LATIN1 version */
419 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 /** byte[]/UTF16 version */
430 static void formatUnsignedLong0UTF16(long val, int shift, byte[] buf, int offset, int len) {
431 int charPos = offset + len;
432 int radix = 1 << shift;
433 int mask = radix - 1;
434 do {
435 StringUTF16.putChar(buf, --charPos, Integer.digits[((int) val) & mask]);
436 val >>>= shift;
437 } while (charPos > offset);
438 }
439
440 /**
441 * Returns a {@code String} object representing the specified
442 * {@code long}. The argument is converted to signed decimal
443 * representation and returned as a string, exactly as if the
444 * argument and the radix 10 were given as arguments to the {@link
445 * #toString(long, int)} method.
446 *
447 * @param i a {@code long} to be converted.
448 * @return a string representation of the argument in base 10.
449 */
450 public static String toString(long i) {
451 int size = stringSize(i);
452 if (COMPACT_STRINGS) {
453 byte[] buf = new byte[size];
454 getChars(i, size, buf);
455 return new String(buf, LATIN1);
456 } else {
457 byte[] buf = new byte[size * 2];
458 getCharsUTF16(i, size, buf);
459 return new String(buf, UTF16);
460 }
461 }
462
463 /**
464 * Returns a string representation of the argument as an unsigned
465 * decimal value.
466 *
467 * The argument is converted to unsigned decimal representation
468 * and returned as a string exactly as if the argument and radix
469 * 10 were given as arguments to the {@link #toUnsignedString(long,
470 * int)} method.
471 *
472 * @param i an integer to be converted to an unsigned string.
473 * @return an unsigned string representation of the argument.
474 * @see #toUnsignedString(long, int)
475 * @since 1.8
476 */
477 public static String toUnsignedString(long i) {
478 return toUnsignedString(i, 10);
479 }
480
481 /**
482 * Places characters representing the long i into the
483 * character array buf. The characters are placed into
484 * the buffer backwards starting with the least significant
485 * digit at the specified index (exclusive), and working
486 * backwards from there.
487 *
488 * @implNote This method converts positive inputs into negative
489 * values, to cover the Long.MIN_VALUE case. Converting otherwise
490 * (negative to positive) will expose -Long.MIN_VALUE that overflows
491 * long.
492 */
493 static void getChars(long i, int index, byte[] buf) {
494 long q;
495 int r;
496 int charPos = index;
497
498 boolean negative = (i < 0);
499 if (!negative) {
500 i = -i;
501 }
502
503 // Get 2 digits/iteration using longs until quotient fits into an int
504 while (i <= Integer.MIN_VALUE) {
505 q = i / 100;
506 r = (int)((q * 100) - i);
507 i = q;
508 buf[--charPos] = Integer.DigitOnes[r];
509 buf[--charPos] = Integer.DigitTens[r];
510 }
511
512 // Get 2 digits/iteration using ints
513 int q2;
514 int i2 = (int)i;
515 while (i2 <= -100) {
516 q2 = i2 / 100;
517 r = (q2 * 100) - i2;
518 i2 = q2;
519 buf[--charPos] = Integer.DigitOnes[r];
520 buf[--charPos] = Integer.DigitTens[r];
521 }
522
523 // We know there are at most two digits left at this point.
524 q2 = i2 / 10;
525 r = (q2 * 10) - i2;
526 buf[--charPos] = (byte)('0' + r);
527
528 // Whatever left is the remaining digit.
529 if (q2 < 0) {
530 buf[--charPos] = (byte)('0' - q2);
531 }
532
533 if (negative) {
534 buf[--charPos] = (byte)'-';
535 }
536 }
537
538 static void getCharsUTF16(long i, int index, byte[] buf) {
539 long q;
540 int r;
541 int charPos = index;
542
543 boolean negative = (i < 0);
544 if (!negative) {
545 i = -i;
546 }
547
548 // Get 2 digits/iteration using longs until quotient fits into an int
549 while (i <= Integer.MIN_VALUE) {
550 q = i / 100;
551 r = (int)((q * 100) - i);
552 i = q;
553 StringUTF16.putChar(buf, --charPos, Integer.DigitOnes[r]);
554 StringUTF16.putChar(buf, --charPos, Integer.DigitTens[r]);
555 }
556
557 // Get 2 digits/iteration using ints
558 int q2;
559 int i2 = (int)i;
560 while (i2 <= -100) {
561 q2 = i2 / 100;
562 r = (q2 * 100) - i2;
563 i2 = q2;
564 StringUTF16.putChar(buf, --charPos, Integer.DigitOnes[r]);
565 StringUTF16.putChar(buf, --charPos, Integer.DigitTens[r]);
566 }
567
568 // We know there are at most two digits left at this point.
569 q2 = i2 / 10;
570 r = (q2 * 10) - i2;
571 StringUTF16.putChar(buf, --charPos, '0' + r);
572
573 // Whatever left is the remaining digit.
574 if (q2 < 0) {
575 StringUTF16.putChar(buf, --charPos, '0' - q2);
576 }
577
578 if (negative) {
579 StringUTF16.putChar(buf, --charPos, '-');
580 }
581 }
582
583 /**
584 * Returns the string representation size for a given long value.
585 *
586 * @param x long value
587 * @return string size
588 *
589 * @implNote There are other ways to compute this: e.g. binary search,
590 * but values are biased heavily towards zero, and therefore linear search
591 * wins. The iteration results are also routinely inlined in the generated
592 * code after loop unrolling.
593 */
594 static int stringSize(long x) {
595 int d = 1;
596 if (x >= 0) {
597 d = 0;
598 x = -x;
599 }
600 long p = -10;
601 for (int i = 1; i < 19; i++) {
602 if (x > p)
603 return i + d;
604 p = 10 * p;
605 }
606 return 19 + d;
607 }
608
609 /**
610 * Parses the string argument as a signed {@code long} in the
611 * radix specified by the second argument. The characters in the
612 * string must all be digits of the specified radix (as determined
613 * by whether {@link java.lang.Character#digit(char, int)} returns
614 * a nonnegative value), except that the first character may be an
615 * ASCII minus sign {@code '-'} ({@code '\u005Cu002D'}) to
616 * indicate a negative value or an ASCII plus sign {@code '+'}
617 * ({@code '\u005Cu002B'}) to indicate a positive value. The
618 * resulting {@code long} value is returned.
619 *
620 * <p>Note that neither the character {@code L}
621 * ({@code '\u005Cu004C'}) nor {@code l}
622 * ({@code '\u005Cu006C'}) is permitted to appear at the end
623 * of the string as a type indicator, as would be permitted in
624 * Java programming language source code - except that either
625 * {@code L} or {@code l} may appear as a digit for a
626 * radix greater than or equal to 22.
627 *
628 * <p>An exception of type {@code NumberFormatException} is
629 * thrown if any of the following situations occurs:
630 * <ul>
631 *
632 * <li>The first argument is {@code null} or is a string of
633 * length zero.
634 *
635 * <li>The {@code radix} is either smaller than {@link
636 * java.lang.Character#MIN_RADIX} or larger than {@link
637 * java.lang.Character#MAX_RADIX}.
638 *
639 * <li>Any character of the string is not a digit of the specified
640 * radix, except that the first character may be a minus sign
641 * {@code '-'} ({@code '\u005Cu002d'}) or plus sign {@code
642 * '+'} ({@code '\u005Cu002B'}) provided that the string is
643 * longer than length 1.
644 *
645 * <li>The value represented by the string is not a value of type
646 * {@code long}.
647 * </ul>
648 *
649 * <p>Examples:
650 * <blockquote><pre>
651 * parseLong("0", 10) returns 0L
652 * parseLong("473", 10) returns 473L
653 * parseLong("+42", 10) returns 42L
654 * parseLong("-0", 10) returns 0L
655 * parseLong("-FF", 16) returns -255L
656 * parseLong("1100110", 2) returns 102L
657 * parseLong("99", 8) throws a NumberFormatException
658 * parseLong("Hazelnut", 10) throws a NumberFormatException
659 * parseLong("Hazelnut", 36) returns 1356099454469L
660 * </pre></blockquote>
661 *
662 * @param s the {@code String} containing the
663 * {@code long} representation to be parsed.
664 * @param radix the radix to be used while parsing {@code s}.
665 * @return the {@code long} represented by the string argument in
666 * the specified radix.
667 * @throws NumberFormatException if the string does not contain a
668 * parsable {@code long}.
669 */
670 public static long parseLong(String s, int radix)
671 throws NumberFormatException
672 {
673 if (s == null) {
674 throw new NumberFormatException("null");
675 }
676
677 if (radix < Character.MIN_RADIX) {
678 throw new NumberFormatException("radix " + radix +
679 " less than Character.MIN_RADIX");
680 }
681 if (radix > Character.MAX_RADIX) {
682 throw new NumberFormatException("radix " + radix +
683 " greater than Character.MAX_RADIX");
684 }
685
686 boolean negative = false;
687 int i = 0, len = s.length();
688 long limit = -Long.MAX_VALUE;
689
690 if (len > 0) {
691 char firstChar = s.charAt(0);
692 if (firstChar < '0') { // Possible leading "+" or "-"
693 if (firstChar == '-') {
694 negative = true;
695 limit = Long.MIN_VALUE;
696 } else if (firstChar != '+') {
697 throw NumberFormatException.forInputString(s);
698 }
699
700 if (len == 1) { // Cannot have lone "+" or "-"
701 throw NumberFormatException.forInputString(s);
702 }
703 i++;
704 }
705 long multmin = limit / radix;
706 long result = 0;
707 while (i < len) {
708 // Accumulating negatively avoids surprises near MAX_VALUE
709 int digit = Character.digit(s.charAt(i++),radix);
710 if (digit < 0 || result < multmin) {
711 throw NumberFormatException.forInputString(s);
712 }
713 result *= radix;
714 if (result < limit + digit) {
715 throw NumberFormatException.forInputString(s);
716 }
717 result -= digit;
718 }
719 return negative ? result : -result;
720 } else {
721 throw NumberFormatException.forInputString(s);
722 }
723 }
724
725 /**
726 * Parses the {@link CharSequence} argument as a signed {@code long} in
727 * the specified {@code radix}, beginning at the specified
728 * {@code beginIndex} and extending to {@code endIndex - 1}.
729 *
730 * <p>The method does not take steps to guard against the
731 * {@code CharSequence} being mutated while parsing.
732 *
733 * @param s the {@code CharSequence} containing the {@code long}
734 * representation to be parsed
735 * @param beginIndex the beginning index, inclusive.
736 * @param endIndex the ending index, exclusive.
737 * @param radix the radix to be used while parsing {@code s}.
738 * @return the signed {@code long} represented by the subsequence in
739 * the specified radix.
740 * @throws NullPointerException if {@code s} is null.
741 * @throws IndexOutOfBoundsException if {@code beginIndex} is
742 * negative, or if {@code beginIndex} is greater than
743 * {@code endIndex} or if {@code endIndex} is greater than
744 * {@code s.length()}.
745 * @throws NumberFormatException if the {@code CharSequence} does not
746 * contain a parsable {@code int} in the specified
747 * {@code radix}, or if {@code radix} is either smaller than
748 * {@link java.lang.Character#MIN_RADIX} or larger than
749 * {@link java.lang.Character#MAX_RADIX}.
750 * @since 9
751 */
752 public static long parseLong(CharSequence s, int beginIndex, int endIndex, int radix)
753 throws NumberFormatException {
754 s = Objects.requireNonNull(s);
755
756 if (beginIndex < 0 || beginIndex > endIndex || endIndex > s.length()) {
757 throw new IndexOutOfBoundsException();
758 }
759 if (radix < Character.MIN_RADIX) {
760 throw new NumberFormatException("radix " + radix +
761 " less than Character.MIN_RADIX");
762 }
763 if (radix > Character.MAX_RADIX) {
764 throw new NumberFormatException("radix " + radix +
765 " greater than Character.MAX_RADIX");
766 }
767
768 boolean negative = false;
769 int i = beginIndex;
770 long limit = -Long.MAX_VALUE;
771
772 if (i < endIndex) {
773 char firstChar = s.charAt(i);
774 if (firstChar < '0') { // Possible leading "+" or "-"
775 if (firstChar == '-') {
776 negative = true;
777 limit = Long.MIN_VALUE;
778 } else if (firstChar != '+') {
779 throw NumberFormatException.forCharSequence(s, beginIndex,
780 endIndex, i);
781 }
782 i++;
783 }
784 if (i >= endIndex) { // Cannot have lone "+", "-" or ""
785 throw NumberFormatException.forCharSequence(s, beginIndex,
786 endIndex, i);
787 }
788 long multmin = limit / radix;
789 long result = 0;
790 while (i < endIndex) {
791 // Accumulating negatively avoids surprises near MAX_VALUE
792 int digit = Character.digit(s.charAt(i), radix);
793 if (digit < 0 || result < multmin) {
794 throw NumberFormatException.forCharSequence(s, beginIndex,
795 endIndex, i);
796 }
797 result *= radix;
798 if (result < limit + digit) {
799 throw NumberFormatException.forCharSequence(s, beginIndex,
800 endIndex, i);
801 }
802 i++;
803 result -= digit;
804 }
805 return negative ? result : -result;
806 } else {
807 throw new NumberFormatException("");
808 }
809 }
810
811 /**
812 * Parses the string argument as a signed decimal {@code long}.
813 * The characters in the string must all be decimal digits, except
814 * that the first character may be an ASCII minus sign {@code '-'}
815 * ({@code \u005Cu002D'}) to indicate a negative value or an
816 * ASCII plus sign {@code '+'} ({@code '\u005Cu002B'}) to
817 * indicate a positive value. The resulting {@code long} value is
818 * returned, exactly as if the argument and the radix {@code 10}
819 * were given as arguments to the {@link
820 * #parseLong(java.lang.String, int)} method.
821 *
822 * <p>Note that neither the character {@code L}
823 * ({@code '\u005Cu004C'}) nor {@code l}
824 * ({@code '\u005Cu006C'}) is permitted to appear at the end
825 * of the string as a type indicator, as would be permitted in
826 * Java programming language source code.
827 *
828 * @param s a {@code String} containing the {@code long}
829 * representation to be parsed
830 * @return the {@code long} represented by the argument in
831 * decimal.
832 * @throws NumberFormatException if the string does not contain a
833 * parsable {@code long}.
834 */
835 public static long parseLong(String s) throws NumberFormatException {
836 return parseLong(s, 10);
837 }
838
839 /**
840 * Parses the string argument as an unsigned {@code long} in the
841 * radix specified by the second argument. An unsigned integer
842 * maps the values usually associated with negative numbers to
843 * positive numbers larger than {@code MAX_VALUE}.
844 *
845 * The characters in the string must all be digits of the
846 * specified radix (as determined by whether {@link
847 * java.lang.Character#digit(char, int)} returns a nonnegative
848 * value), except that the first character may be an ASCII plus
849 * sign {@code '+'} ({@code '\u005Cu002B'}). The resulting
850 * integer value is returned.
851 *
852 * <p>An exception of type {@code NumberFormatException} is
853 * thrown if any of the following situations occurs:
854 * <ul>
855 * <li>The first argument is {@code null} or is a string of
856 * length zero.
857 *
858 * <li>The radix is either smaller than
859 * {@link java.lang.Character#MIN_RADIX} or
860 * larger than {@link java.lang.Character#MAX_RADIX}.
861 *
862 * <li>Any character of the string is not a digit of the specified
863 * radix, except that the first character may be a plus sign
864 * {@code '+'} ({@code '\u005Cu002B'}) provided that the
865 * string is longer than length 1.
866 *
867 * <li>The value represented by the string is larger than the
868 * largest unsigned {@code long}, 2<sup>64</sup>-1.
869 *
870 * </ul>
871 *
872 *
873 * @param s the {@code String} containing the unsigned integer
874 * representation to be parsed
875 * @param radix the radix to be used while parsing {@code s}.
876 * @return the unsigned {@code long} represented by the string
877 * argument in the specified radix.
878 * @throws NumberFormatException if the {@code String}
879 * does not contain a parsable {@code long}.
880 * @since 1.8
881 */
882 public static long parseUnsignedLong(String s, int radix)
883 throws NumberFormatException {
884 if (s == null) {
885 throw new NumberFormatException("null");
886 }
887
888 int len = s.length();
889 if (len > 0) {
890 char firstChar = s.charAt(0);
891 if (firstChar == '-') {
892 throw new
893 NumberFormatException(String.format("Illegal leading minus sign " +
894 "on unsigned string %s.", s));
895 } else {
896 if (len <= 12 || // Long.MAX_VALUE in Character.MAX_RADIX is 13 digits
897 (radix == 10 && len <= 18) ) { // Long.MAX_VALUE in base 10 is 19 digits
898 return parseLong(s, radix);
899 }
900
901 // No need for range checks on len due to testing above.
902 long first = parseLong(s, 0, len - 1, radix);
903 int second = Character.digit(s.charAt(len - 1), radix);
904 if (second < 0) {
905 throw new NumberFormatException("Bad digit at end of " + s);
906 }
907 long result = first * radix + second;
908
909 /*
910 * Test leftmost bits of multiprecision extension of first*radix
911 * for overflow. The number of bits needed is defined by
912 * GUARD_BIT = ceil(log2(Character.MAX_RADIX)) + 1 = 7. Then
913 * int guard = radix*(int)(first >>> (64 - GUARD_BIT)) and
914 * overflow is tested by splitting guard in the ranges
915 * guard < 92, 92 <= guard < 128, and 128 <= guard, where
916 * 92 = 128 - Character.MAX_RADIX. Note that guard cannot take
917 * on a value which does not include a prime factor in the legal
918 * radix range.
919 */
920 int guard = radix * (int) (first >>> 57);
921 if (guard >= 128 ||
922 (result >= 0 && guard >= 128 - Character.MAX_RADIX)) {
923 /*
924 * For purposes of exposition, the programmatic statements
925 * below should be taken to be multi-precision, i.e., not
926 * subject to overflow.
927 *
928 * A) Condition guard >= 128:
929 * If guard >= 128 then first*radix >= 2^7 * 2^57 = 2^64
930 * hence always overflow.
931 *
932 * B) Condition guard < 92:
933 * Define left7 = first >>> 57.
934 * Given first = (left7 * 2^57) + (first & (2^57 - 1)) then
935 * result <= (radix*left7)*2^57 + radix*(2^57 - 1) + second.
936 * Thus if radix*left7 < 92, radix <= 36, and second < 36,
937 * then result < 92*2^57 + 36*(2^57 - 1) + 36 = 2^64 hence
938 * never overflow.
939 *
940 * C) Condition 92 <= guard < 128:
941 * first*radix + second >= radix*left7*2^57 + second
942 * so that first*radix + second >= 92*2^57 + 0 > 2^63
943 *
944 * D) Condition guard < 128:
945 * radix*first <= (radix*left7) * 2^57 + radix*(2^57 - 1)
946 * so
947 * radix*first + second <= (radix*left7) * 2^57 + radix*(2^57 - 1) + 36
948 * thus
949 * radix*first + second < 128 * 2^57 + 36*2^57 - radix + 36
950 * whence
951 * radix*first + second < 2^64 + 2^6*2^57 = 2^64 + 2^63
952 *
953 * E) Conditions C, D, and result >= 0:
954 * C and D combined imply the mathematical result
955 * 2^63 < first*radix + second < 2^64 + 2^63. The lower
956 * bound is therefore negative as a signed long, but the
957 * upper bound is too small to overflow again after the
958 * signed long overflows to positive above 2^64 - 1. Hence
959 * result >= 0 implies overflow given C and D.
960 */
961 throw new NumberFormatException(String.format("String value %s exceeds " +
962 "range of unsigned long.", s));
963 }
964 return result;
965 }
966 } else {
967 throw NumberFormatException.forInputString(s);
968 }
969 }
970
971 /**
972 * Parses the {@link CharSequence} argument as an unsigned {@code long} in
973 * the specified {@code radix}, beginning at the specified
974 * {@code beginIndex} and extending to {@code endIndex - 1}.
975 *
976 * <p>The method does not take steps to guard against the
977 * {@code CharSequence} being mutated while parsing.
978 *
979 * @param s the {@code CharSequence} containing the unsigned
980 * {@code long} representation to be parsed
981 * @param beginIndex the beginning index, inclusive.
982 * @param endIndex the ending index, exclusive.
983 * @param radix the radix to be used while parsing {@code s}.
984 * @return the unsigned {@code long} represented by the subsequence in
985 * the specified radix.
986 * @throws NullPointerException if {@code s} is null.
987 * @throws IndexOutOfBoundsException if {@code beginIndex} is
988 * negative, or if {@code beginIndex} is greater than
989 * {@code endIndex} or if {@code endIndex} is greater than
990 * {@code s.length()}.
991 * @throws NumberFormatException if the {@code CharSequence} does not
992 * contain a parsable unsigned {@code long} in the specified
993 * {@code radix}, or if {@code radix} is either smaller than
994 * {@link java.lang.Character#MIN_RADIX} or larger than
995 * {@link java.lang.Character#MAX_RADIX}.
996 * @since 9
997 */
998 public static long parseUnsignedLong(CharSequence s, int beginIndex, int endIndex, int radix)
999 throws NumberFormatException {
1000 s = Objects.requireNonNull(s);
1001
1002 if (beginIndex < 0 || beginIndex > endIndex || endIndex > s.length()) {
1003 throw new IndexOutOfBoundsException();
1004 }
1005 int start = beginIndex, len = endIndex - beginIndex;
1006
1007 if (len > 0) {
1008 char firstChar = s.charAt(start);
1009 if (firstChar == '-') {
1010 throw new NumberFormatException(String.format("Illegal leading minus sign " +
1011 "on unsigned string %s.", s.subSequence(start, start + len)));
1012 } else {
1013 if (len <= 12 || // Long.MAX_VALUE in Character.MAX_RADIX is 13 digits
1014 (radix == 10 && len <= 18) ) { // Long.MAX_VALUE in base 10 is 19 digits
1015 return parseLong(s, start, start + len, radix);
1016 }
1017
1018 // No need for range checks on end due to testing above.
1019 long first = parseLong(s, start, start + len - 1, radix);
1020 int second = Character.digit(s.charAt(start + len - 1), radix);
1021 if (second < 0) {
1022 throw new NumberFormatException("Bad digit at end of " +
1023 s.subSequence(start, start + len));
1024 }
1025 long result = first * radix + second;
1026
1027 /*
1028 * Test leftmost bits of multiprecision extension of first*radix
1029 * for overflow. The number of bits needed is defined by
1030 * GUARD_BIT = ceil(log2(Character.MAX_RADIX)) + 1 = 7. Then
1031 * int guard = radix*(int)(first >>> (64 - GUARD_BIT)) and
1032 * overflow is tested by splitting guard in the ranges
1033 * guard < 92, 92 <= guard < 128, and 128 <= guard, where
1034 * 92 = 128 - Character.MAX_RADIX. Note that guard cannot take
1035 * on a value which does not include a prime factor in the legal
1036 * radix range.
1037 */
1038 int guard = radix * (int) (first >>> 57);
1039 if (guard >= 128 ||
1040 (result >= 0 && guard >= 128 - Character.MAX_RADIX)) {
1041 /*
1042 * For purposes of exposition, the programmatic statements
1043 * below should be taken to be multi-precision, i.e., not
1044 * subject to overflow.
1045 *
1046 * A) Condition guard >= 128:
1047 * If guard >= 128 then first*radix >= 2^7 * 2^57 = 2^64
1048 * hence always overflow.
1049 *
1050 * B) Condition guard < 92:
1051 * Define left7 = first >>> 57.
1052 * Given first = (left7 * 2^57) + (first & (2^57 - 1)) then
1053 * result <= (radix*left7)*2^57 + radix*(2^57 - 1) + second.
1054 * Thus if radix*left7 < 92, radix <= 36, and second < 36,
1055 * then result < 92*2^57 + 36*(2^57 - 1) + 36 = 2^64 hence
1056 * never overflow.
1057 *
1058 * C) Condition 92 <= guard < 128:
1059 * first*radix + second >= radix*left7*2^57 + second
1060 * so that first*radix + second >= 92*2^57 + 0 > 2^63
1061 *
1062 * D) Condition guard < 128:
1063 * radix*first <= (radix*left7) * 2^57 + radix*(2^57 - 1)
1064 * so
1065 * radix*first + second <= (radix*left7) * 2^57 + radix*(2^57 - 1) + 36
1066 * thus
1067 * radix*first + second < 128 * 2^57 + 36*2^57 - radix + 36
1068 * whence
1069 * radix*first + second < 2^64 + 2^6*2^57 = 2^64 + 2^63
1070 *
1071 * E) Conditions C, D, and result >= 0:
1072 * C and D combined imply the mathematical result
1073 * 2^63 < first*radix + second < 2^64 + 2^63. The lower
1074 * bound is therefore negative as a signed long, but the
1075 * upper bound is too small to overflow again after the
1076 * signed long overflows to positive above 2^64 - 1. Hence
1077 * result >= 0 implies overflow given C and D.
1078 */
1079 throw new NumberFormatException(String.format("String value %s exceeds " +
1080 "range of unsigned long.", s.subSequence(start, start + len)));
1081 }
1082 return result;
1083 }
1084 } else {
1085 throw NumberFormatException.forInputString("");
1086 }
1087 }
1088
1089 /**
1090 * Parses the string argument as an unsigned decimal {@code long}. The
1091 * characters in the string must all be decimal digits, except
1092 * that the first character may be an ASCII plus sign {@code
1093 * '+'} ({@code '\u005Cu002B'}). The resulting integer value
1094 * is returned, exactly as if the argument and the radix 10 were
1095 * given as arguments to the {@link
1096 * #parseUnsignedLong(java.lang.String, int)} method.
1097 *
1098 * @param s a {@code String} containing the unsigned {@code long}
1099 * representation to be parsed
1100 * @return the unsigned {@code long} value represented by the decimal string argument
1101 * @throws NumberFormatException if the string does not contain a
1102 * parsable unsigned integer.
1103 * @since 1.8
1104 */
1105 public static long parseUnsignedLong(String s) throws NumberFormatException {
1106 return parseUnsignedLong(s, 10);
1107 }
1108
1109 /**
1110 * Returns a {@code Long} object holding the value
1111 * extracted from the specified {@code String} when parsed
1112 * with the radix given by the second argument. The first
1113 * argument is interpreted as representing a signed
1114 * {@code long} in the radix specified by the second
1115 * argument, exactly as if the arguments were given to the {@link
1116 * #parseLong(java.lang.String, int)} method. The result is a
1117 * {@code Long} object that represents the {@code long}
1118 * value specified by the string.
1119 *
1120 * <p>In other words, this method returns a {@code Long} object equal
1121 * to the value of:
1122 *
1123 * <blockquote>
1124 * {@code new Long(Long.parseLong(s, radix))}
1125 * </blockquote>
1126 *
1127 * @param s the string to be parsed
1128 * @param radix the radix to be used in interpreting {@code s}
1129 * @return a {@code Long} object holding the value
1130 * represented by the string argument in the specified
1131 * radix.
1132 * @throws NumberFormatException If the {@code String} does not
1133 * contain a parsable {@code long}.
1134 */
1135 public static Long valueOf(String s, int radix) throws NumberFormatException {
1136 return Long.valueOf(parseLong(s, radix));
1137 }
1138
1139 /**
1140 * Returns a {@code Long} object holding the value
1141 * of the specified {@code String}. The argument is
1142 * interpreted as representing a signed decimal {@code long},
1143 * exactly as if the argument were given to the {@link
1144 * #parseLong(java.lang.String)} method. The result is a
1145 * {@code Long} object that represents the integer value
1146 * specified by the string.
1147 *
1148 * <p>In other words, this method returns a {@code Long} object
1149 * equal to the value of:
1150 *
1151 * <blockquote>
1152 * {@code new Long(Long.parseLong(s))}
1153 * </blockquote>
1154 *
1155 * @param s the string to be parsed.
1156 * @return a {@code Long} object holding the value
1157 * represented by the string argument.
1158 * @throws NumberFormatException If the string cannot be parsed
1159 * as a {@code long}.
1160 */
1161 public static Long valueOf(String s) throws NumberFormatException
1162 {
1163 return Long.valueOf(parseLong(s, 10));
1164 }
1165
1166 private static class LongCache {
1167 private LongCache(){}
1168
1169 static final Long cache[] = new Long[-(-128) + 127 + 1];
1170
1171 static {
1172 for(int i = 0; i < cache.length; i++)
1173 cache[i] = new Long(i - 128);
1174 }
1175 }
1176
1177 /**
1178 * Returns a {@code Long} instance representing the specified
1179 * {@code long} value.
1180 * If a new {@code Long} instance is not required, this method
1181 * should generally be used in preference to the constructor
1182 * {@link #Long(long)}, as this method is likely to yield
1183 * significantly better space and time performance by caching
1184 * frequently requested values.
1185 *
1186 * Note that unlike the {@linkplain Integer#valueOf(int)
1187 * corresponding method} in the {@code Integer} class, this method
1188 * is <em>not</em> required to cache values within a particular
1189 * range.
1190 *
1191 * @param l a long value.
1192 * @return a {@code Long} instance representing {@code l}.
1193 * @since 1.5
1194 */
1195 @HotSpotIntrinsicCandidate
1196 public static Long valueOf(long l) {
1197 final int offset = 128;
1198 if (l >= -128 && l <= 127) { // will cache
1199 return LongCache.cache[(int)l + offset];
1200 }
1201 return new Long(l);
1202 }
1203
1204 /**
1205 * Decodes a {@code String} into a {@code Long}.
1206 * Accepts decimal, hexadecimal, and octal numbers given by the
1207 * following grammar:
1208 *
1209 * <blockquote>
1210 * <dl>
1211 * <dt><i>DecodableString:</i>
1212 * <dd><i>Sign<sub>opt</sub> DecimalNumeral</i>
1213 * <dd><i>Sign<sub>opt</sub></i> {@code 0x} <i>HexDigits</i>
1214 * <dd><i>Sign<sub>opt</sub></i> {@code 0X} <i>HexDigits</i>
1215 * <dd><i>Sign<sub>opt</sub></i> {@code #} <i>HexDigits</i>
1216 * <dd><i>Sign<sub>opt</sub></i> {@code 0} <i>OctalDigits</i>
1217 *
1218 * <dt><i>Sign:</i>
1219 * <dd>{@code -}
1220 * <dd>{@code +}
1221 * </dl>
1222 * </blockquote>
1223 *
1224 * <i>DecimalNumeral</i>, <i>HexDigits</i>, and <i>OctalDigits</i>
1225 * are as defined in section 3.10.1 of
1226 * <cite>The Java™ Language Specification</cite>,
1227 * except that underscores are not accepted between digits.
1228 *
1229 * <p>The sequence of characters following an optional
1230 * sign and/or radix specifier ("{@code 0x}", "{@code 0X}",
1231 * "{@code #}", or leading zero) is parsed as by the {@code
1232 * Long.parseLong} method with the indicated radix (10, 16, or 8).
1233 * This sequence of characters must represent a positive value or
1234 * a {@link NumberFormatException} will be thrown. The result is
1235 * negated if first character of the specified {@code String} is
1236 * the minus sign. No whitespace characters are permitted in the
1237 * {@code String}.
1238 *
1239 * @param nm the {@code String} to decode.
1240 * @return a {@code Long} object holding the {@code long}
1241 * value represented by {@code nm}
1242 * @throws NumberFormatException if the {@code String} does not
1243 * contain a parsable {@code long}.
1244 * @see java.lang.Long#parseLong(String, int)
1245 * @since 1.2
1246 */
1247 public static Long decode(String nm) throws NumberFormatException {
1248 int radix = 10;
1249 int index = 0;
1250 boolean negative = false;
1251 Long result;
1252
1253 if (nm.length() == 0)
1254 throw new NumberFormatException("Zero length string");
1255 char firstChar = nm.charAt(0);
1256 // Handle sign, if present
1257 if (firstChar == '-') {
1258 negative = true;
1259 index++;
1260 } else if (firstChar == '+')
1261 index++;
1262
1263 // Handle radix specifier, if present
1264 if (nm.startsWith("0x", index) || nm.startsWith("0X", index)) {
1265 index += 2;
1266 radix = 16;
1267 }
1268 else if (nm.startsWith("#", index)) {
1269 index ++;
1270 radix = 16;
1271 }
1272 else if (nm.startsWith("0", index) && nm.length() > 1 + index) {
1273 index ++;
1274 radix = 8;
1275 }
1276
1277 if (nm.startsWith("-", index) || nm.startsWith("+", index))
1278 throw new NumberFormatException("Sign character in wrong position");
1279
1280 try {
1281 result = Long.valueOf(nm.substring(index), radix);
1282 result = negative ? Long.valueOf(-result.longValue()) : result;
1283 } catch (NumberFormatException e) {
1284 // If number is Long.MIN_VALUE, we'll end up here. The next line
1285 // handles this case, and causes any genuine format error to be
1286 // rethrown.
1287 String constant = negative ? ("-" + nm.substring(index))
1288 : nm.substring(index);
1289 result = Long.valueOf(constant, radix);
1290 }
1291 return result;
1292 }
1293
1294 /**
1295 * The value of the {@code Long}.
1296 *
1297 * @serial
1298 */
1299 private final long value;
1300
1301 /**
1302 * Constructs a newly allocated {@code Long} object that
1303 * represents the specified {@code long} argument.
1304 *
1305 * @param value the value to be represented by the
1306 * {@code Long} object.
1307 */
1308 public Long(long value) {
1309 this.value = value;
1310 }
1311
1312 /**
1313 * Constructs a newly allocated {@code Long} object that
1314 * represents the {@code long} value indicated by the
1315 * {@code String} parameter. The string is converted to a
1316 * {@code long} value in exactly the manner used by the
1317 * {@code parseLong} method for radix 10.
1318 *
1319 * @param s the {@code String} to be converted to a
1320 * {@code Long}.
1321 * @throws NumberFormatException if the {@code String} does not
1322 * contain a parsable {@code long}.
1323 * @see java.lang.Long#parseLong(java.lang.String, int)
1324 */
1325 public Long(String s) throws NumberFormatException {
1326 this.value = parseLong(s, 10);
1327 }
1328
1329 /**
1330 * Returns the value of this {@code Long} as a {@code byte} after
1331 * a narrowing primitive conversion.
1332 * @jls 5.1.3 Narrowing Primitive Conversions
1333 */
1334 public byte byteValue() {
1335 return (byte)value;
1336 }
1337
1338 /**
1339 * Returns the value of this {@code Long} as a {@code short} after
1340 * a narrowing primitive conversion.
1341 * @jls 5.1.3 Narrowing Primitive Conversions
1342 */
1343 public short shortValue() {
1344 return (short)value;
1345 }
1346
1347 /**
1348 * Returns the value of this {@code Long} as an {@code int} after
1349 * a narrowing primitive conversion.
1350 * @jls 5.1.3 Narrowing Primitive Conversions
1351 */
1352 public int intValue() {
1353 return (int)value;
1354 }
1355
1356 /**
1357 * Returns the value of this {@code Long} as a
1358 * {@code long} value.
1359 */
1360 @HotSpotIntrinsicCandidate
1361 public long longValue() {
1362 return value;
1363 }
1364
1365 /**
1366 * Returns the value of this {@code Long} as a {@code float} after
1367 * a widening primitive conversion.
1368 * @jls 5.1.2 Widening Primitive Conversions
1369 */
1370 public float floatValue() {
1371 return (float)value;
1372 }
1373
1374 /**
1375 * Returns the value of this {@code Long} as a {@code double}
1376 * after a widening primitive conversion.
1377 * @jls 5.1.2 Widening Primitive Conversions
1378 */
1379 public double doubleValue() {
1380 return (double)value;
1381 }
1382
1383 /**
1384 * Returns a {@code String} object representing this
1385 * {@code Long}'s value. The value is converted to signed
1386 * decimal representation and returned as a string, exactly as if
1387 * the {@code long} value were given as an argument to the
1388 * {@link java.lang.Long#toString(long)} method.
1389 *
1390 * @return a string representation of the value of this object in
1391 * base 10.
1392 */
1393 public String toString() {
1394 return toString(value);
1395 }
1396
1397 /**
1398 * Returns a hash code for this {@code Long}. The result is
1399 * the exclusive OR of the two halves of the primitive
1400 * {@code long} value held by this {@code Long}
1401 * object. That is, the hashcode is the value of the expression:
1402 *
1403 * <blockquote>
1404 * {@code (int)(this.longValue()^(this.longValue()>>>32))}
1405 * </blockquote>
1406 *
1407 * @return a hash code value for this object.
1408 */
1409 @Override
1410 public int hashCode() {
1411 return Long.hashCode(value);
1412 }
1413
1414 /**
1415 * Returns a hash code for a {@code long} value; compatible with
1416 * {@code Long.hashCode()}.
1417 *
1418 * @param value the value to hash
1419 * @return a hash code value for a {@code long} value.
1420 * @since 1.8
1421 */
1422 public static int hashCode(long value) {
1423 return (int)(value ^ (value >>> 32));
1424 }
1425
1426 /**
1427 * Compares this object to the specified object. The result is
1428 * {@code true} if and only if the argument is not
1429 * {@code null} and is a {@code Long} object that
1430 * contains the same {@code long} value as this object.
1431 *
1432 * @param obj the object to compare with.
1433 * @return {@code true} if the objects are the same;
1434 * {@code false} otherwise.
1435 */
1436 public boolean equals(Object obj) {
1437 if (obj instanceof Long) {
1438 return value == ((Long)obj).longValue();
1439 }
1440 return false;
1441 }
1442
1443 /**
1444 * Determines the {@code long} value of the system property
1445 * with the specified name.
1446 *
1447 * <p>The first argument is treated as the name of a system
1448 * property. System properties are accessible through the {@link
1449 * java.lang.System#getProperty(java.lang.String)} method. The
1450 * string value of this property is then interpreted as a {@code
1451 * long} value using the grammar supported by {@link Long#decode decode}
1452 * and a {@code Long} object representing this value is returned.
1453 *
1454 * <p>If there is no property with the specified name, if the
1455 * specified name is empty or {@code null}, or if the property
1456 * does not have the correct numeric format, then {@code null} is
1457 * returned.
1458 *
1459 * <p>In other words, this method returns a {@code Long} object
1460 * equal to the value of:
1461 *
1462 * <blockquote>
1463 * {@code getLong(nm, null)}
1464 * </blockquote>
1465 *
1466 * @param nm property name.
1467 * @return the {@code Long} value of the property.
1468 * @throws SecurityException for the same reasons as
1469 * {@link System#getProperty(String) System.getProperty}
1470 * @see java.lang.System#getProperty(java.lang.String)
1471 * @see java.lang.System#getProperty(java.lang.String, java.lang.String)
1472 */
1473 public static Long getLong(String nm) {
1474 return getLong(nm, null);
1475 }
1476
1477 /**
1478 * Determines the {@code long} value of the system property
1479 * with the specified name.
1480 *
1481 * <p>The first argument is treated as the name of a system
1482 * property. System properties are accessible through the {@link
1483 * java.lang.System#getProperty(java.lang.String)} method. The
1484 * string value of this property is then interpreted as a {@code
1485 * long} value using the grammar supported by {@link Long#decode decode}
1486 * and a {@code Long} object representing this value is returned.
1487 *
1488 * <p>The second argument is the default value. A {@code Long} object
1489 * that represents the value of the second argument is returned if there
1490 * is no property of the specified name, if the property does not have
1491 * the correct numeric format, or if the specified name is empty or null.
1492 *
1493 * <p>In other words, this method returns a {@code Long} object equal
1494 * to the value of:
1495 *
1496 * <blockquote>
1497 * {@code getLong(nm, new Long(val))}
1498 * </blockquote>
1499 *
1500 * but in practice it may be implemented in a manner such as:
1501 *
1502 * <blockquote><pre>
1503 * Long result = getLong(nm, null);
1504 * return (result == null) ? new Long(val) : result;
1505 * </pre></blockquote>
1506 *
1507 * to avoid the unnecessary allocation of a {@code Long} object when
1508 * the default value is not needed.
1509 *
1510 * @param nm property name.
1511 * @param val default value.
1512 * @return the {@code Long} value of the property.
1513 * @throws SecurityException for the same reasons as
1514 * {@link System#getProperty(String) System.getProperty}
1515 * @see java.lang.System#getProperty(java.lang.String)
1516 * @see java.lang.System#getProperty(java.lang.String, java.lang.String)
1517 */
1518 public static Long getLong(String nm, long val) {
1519 Long result = Long.getLong(nm, null);
1520 return (result == null) ? Long.valueOf(val) : result;
1521 }
1522
1523 /**
1524 * Returns the {@code long} value of the system property with
1525 * the specified name. The first argument is treated as the name
1526 * of a system property. System properties are accessible through
1527 * the {@link java.lang.System#getProperty(java.lang.String)}
1528 * method. The string value of this property is then interpreted
1529 * as a {@code long} value, as per the
1530 * {@link Long#decode decode} method, and a {@code Long} object
1531 * representing this value is returned; in summary:
1532 *
1533 * <ul>
1534 * <li>If the property value begins with the two ASCII characters
1535 * {@code 0x} or the ASCII character {@code #}, not followed by
1536 * a minus sign, then the rest of it is parsed as a hexadecimal integer
1537 * exactly as for the method {@link #valueOf(java.lang.String, int)}
1538 * with radix 16.
1539 * <li>If the property value begins with the ASCII character
1540 * {@code 0} followed by another character, it is parsed as
1541 * an octal integer exactly as by the method {@link
1542 * #valueOf(java.lang.String, int)} with radix 8.
1543 * <li>Otherwise the property value is parsed as a decimal
1544 * integer exactly as by the method
1545 * {@link #valueOf(java.lang.String, int)} with radix 10.
1546 * </ul>
1547 *
1548 * <p>Note that, in every case, neither {@code L}
1549 * ({@code '\u005Cu004C'}) nor {@code l}
1550 * ({@code '\u005Cu006C'}) is permitted to appear at the end
1551 * of the property value as a type indicator, as would be
1552 * permitted in Java programming language source code.
1553 *
1554 * <p>The second argument is the default value. The default value is
1555 * returned if there is no property of the specified name, if the
1556 * property does not have the correct numeric format, or if the
1557 * specified name is empty or {@code null}.
1558 *
1559 * @param nm property name.
1560 * @param val default value.
1561 * @return the {@code Long} value of the property.
1562 * @throws SecurityException for the same reasons as
1563 * {@link System#getProperty(String) System.getProperty}
1564 * @see System#getProperty(java.lang.String)
1565 * @see System#getProperty(java.lang.String, java.lang.String)
1566 */
1567 public static Long getLong(String nm, Long val) {
1568 String v = null;
1569 try {
1570 v = System.getProperty(nm);
1571 } catch (IllegalArgumentException | NullPointerException e) {
1572 }
1573 if (v != null) {
1574 try {
1575 return Long.decode(v);
1576 } catch (NumberFormatException e) {
1577 }
1578 }
1579 return val;
1580 }
1581
1582 /**
1583 * Compares two {@code Long} objects numerically.
1584 *
1585 * @param anotherLong the {@code Long} to be compared.
1586 * @return the value {@code 0} if this {@code Long} is
1587 * equal to the argument {@code Long}; a value less than
1588 * {@code 0} if this {@code Long} is numerically less
1589 * than the argument {@code Long}; and a value greater
1590 * than {@code 0} if this {@code Long} is numerically
1591 * greater than the argument {@code Long} (signed
1592 * comparison).
1593 * @since 1.2
1594 */
1595 public int compareTo(Long anotherLong) {
1596 return compare(this.value, anotherLong.value);
1597 }
1598
1599 /**
1600 * Compares two {@code long} values numerically.
1601 * The value returned is identical to what would be returned by:
1602 * <pre>
1603 * Long.valueOf(x).compareTo(Long.valueOf(y))
1604 * </pre>
1605 *
1606 * @param x the first {@code long} to compare
1607 * @param y the second {@code long} to compare
1608 * @return the value {@code 0} if {@code x == y};
1609 * a value less than {@code 0} if {@code x < y}; and
1610 * a value greater than {@code 0} if {@code x > y}
1611 * @since 1.7
1612 */
1613 public static int compare(long x, long y) {
1614 return (x < y) ? -1 : ((x == y) ? 0 : 1);
1615 }
1616
1617 /**
1618 * Compares two {@code long} values numerically treating the values
1619 * as unsigned.
1620 *
1621 * @param x the first {@code long} to compare
1622 * @param y the second {@code long} to compare
1623 * @return the value {@code 0} if {@code x == y}; a value less
1624 * than {@code 0} if {@code x < y} as unsigned values; and
1625 * a value greater than {@code 0} if {@code x > y} as
1626 * unsigned values
1627 * @since 1.8
1628 */
1629 public static int compareUnsigned(long x, long y) {
1630 return compare(x + MIN_VALUE, y + MIN_VALUE);
1631 }
1632
1633
1634 /**
1635 * Returns the unsigned quotient of dividing the first argument by
1636 * the second where each argument and the result is interpreted as
1637 * an unsigned value.
1638 *
1639 * <p>Note that in two's complement arithmetic, the three other
1640 * basic arithmetic operations of add, subtract, and multiply are
1641 * bit-wise identical if the two operands are regarded as both
1642 * being signed or both being unsigned. Therefore separate {@code
1643 * addUnsigned}, etc. methods are not provided.
1644 *
1645 * @param dividend the value to be divided
1646 * @param divisor the value doing the dividing
1647 * @return the unsigned quotient of the first argument divided by
1648 * the second argument
1649 * @see #remainderUnsigned
1650 * @since 1.8
1651 */
1652 public static long divideUnsigned(long dividend, long divisor) {
1653 if (divisor < 0L) { // signed comparison
1654 // Answer must be 0 or 1 depending on relative magnitude
1655 // of dividend and divisor.
1656 return (compareUnsigned(dividend, divisor)) < 0 ? 0L :1L;
1657 }
1658
1659 if (dividend > 0) // Both inputs non-negative
1660 return dividend/divisor;
1661 else {
1662 /*
1663 * For simple code, leveraging BigInteger. Longer and faster
1664 * code written directly in terms of operations on longs is
1665 * possible; see "Hacker's Delight" for divide and remainder
1666 * algorithms.
1667 */
1668 return toUnsignedBigInteger(dividend).
1669 divide(toUnsignedBigInteger(divisor)).longValue();
1670 }
1671 }
1672
1673 /**
1674 * Returns the unsigned remainder from dividing the first argument
1675 * by the second where each argument and the result is interpreted
1676 * as an unsigned value.
1677 *
1678 * @param dividend the value to be divided
1679 * @param divisor the value doing the dividing
1680 * @return the unsigned remainder of the first argument divided by
1681 * the second argument
1682 * @see #divideUnsigned
1683 * @since 1.8
1684 */
1685 public static long remainderUnsigned(long dividend, long divisor) {
1686 if (dividend > 0 && divisor > 0) { // signed comparisons
1687 return dividend % divisor;
1688 } else {
1689 if (compareUnsigned(dividend, divisor) < 0) // Avoid explicit check for 0 divisor
1690 return dividend;
1691 else
1692 return toUnsignedBigInteger(dividend).
1693 remainder(toUnsignedBigInteger(divisor)).longValue();
1694 }
1695 }
1696
1697 // Bit Twiddling
1698
1699 /**
1700 * The number of bits used to represent a {@code long} value in two's
1701 * complement binary form.
1702 *
1703 * @since 1.5
1704 */
1705 @Native public static final int SIZE = 64;
1706
1707 /**
1708 * The number of bytes used to represent a {@code long} value in two's
1709 * complement binary form.
1710 *
1711 * @since 1.8
1712 */
1713 public static final int BYTES = SIZE / Byte.SIZE;
1714
1715 /**
1716 * Returns a {@code long} value with at most a single one-bit, in the
1717 * position of the highest-order ("leftmost") one-bit in the specified
1718 * {@code long} value. Returns zero if the specified value has no
1719 * one-bits in its two's complement binary representation, that is, if it
1720 * is equal to zero.
1721 *
1722 * @param i the value whose highest one bit is to be computed
1723 * @return a {@code long} value with a single one-bit, in the position
1724 * of the highest-order one-bit in the specified value, or zero if
1725 * the specified value is itself equal to zero.
1726 * @since 1.5
1727 */
1728 public static long highestOneBit(long i) {
1729 // HD, Figure 3-1
1730 i |= (i >> 1);
1731 i |= (i >> 2);
1732 i |= (i >> 4);
1733 i |= (i >> 8);
1734 i |= (i >> 16);
1735 i |= (i >> 32);
1736 return i - (i >>> 1);
1737 }
1738
1739 /**
1740 * Returns a {@code long} value with at most a single one-bit, in the
1741 * position of the lowest-order ("rightmost") one-bit in the specified
1742 * {@code long} value. Returns zero if the specified value has no
1743 * one-bits in its two's complement binary representation, that is, if it
1744 * is equal to zero.
1745 *
1746 * @param i the value whose lowest one bit is to be computed
1747 * @return a {@code long} value with a single one-bit, in the position
1748 * of the lowest-order one-bit in the specified value, or zero if
1749 * the specified value is itself equal to zero.
1750 * @since 1.5
1751 */
1752 public static long lowestOneBit(long i) {
1753 // HD, Section 2-1
1754 return i & -i;
1755 }
1756
1757 /**
1758 * Returns the number of zero bits preceding the highest-order
1759 * ("leftmost") one-bit in the two's complement binary representation
1760 * of the specified {@code long} value. Returns 64 if the
1761 * specified value has no one-bits in its two's complement representation,
1762 * in other words if it is equal to zero.
1763 *
1764 * <p>Note that this method is closely related to the logarithm base 2.
1765 * For all positive {@code long} values x:
1766 * <ul>
1767 * <li>floor(log<sub>2</sub>(x)) = {@code 63 - numberOfLeadingZeros(x)}
1768 * <li>ceil(log<sub>2</sub>(x)) = {@code 64 - numberOfLeadingZeros(x - 1)}
1769 * </ul>
1770 *
1771 * @param i the value whose number of leading zeros is to be computed
1772 * @return the number of zero bits preceding the highest-order
1773 * ("leftmost") one-bit in the two's complement binary representation
1774 * of the specified {@code long} value, or 64 if the value
1775 * is equal to zero.
1776 * @since 1.5
1777 */
1778 @HotSpotIntrinsicCandidate
1779 public static int numberOfLeadingZeros(long i) {
1780 // HD, Figure 5-6
1781 if (i == 0)
1782 return 64;
1783 int n = 1;
1784 int x = (int)(i >>> 32);
1785 if (x == 0) { n += 32; x = (int)i; }
1786 if (x >>> 16 == 0) { n += 16; x <<= 16; }
1787 if (x >>> 24 == 0) { n += 8; x <<= 8; }
1788 if (x >>> 28 == 0) { n += 4; x <<= 4; }
1789 if (x >>> 30 == 0) { n += 2; x <<= 2; }
1790 n -= x >>> 31;
1791 return n;
1792 }
1793
1794 /**
1795 * Returns the number of zero bits following the lowest-order ("rightmost")
1796 * one-bit in the two's complement binary representation of the specified
1797 * {@code long} value. Returns 64 if the specified value has no
1798 * one-bits in its two's complement representation, in other words if it is
1799 * equal to zero.
1800 *
1801 * @param i the value whose number of trailing zeros is to be computed
1802 * @return the number of zero bits following the lowest-order ("rightmost")
1803 * one-bit in the two's complement binary representation of the
1804 * specified {@code long} value, or 64 if the value is equal
1805 * to zero.
1806 * @since 1.5
1807 */
1808 @HotSpotIntrinsicCandidate
1809 public static int numberOfTrailingZeros(long i) {
1810 // HD, Figure 5-14
1811 int x, y;
1812 if (i == 0) return 64;
1813 int n = 63;
1814 y = (int)i; if (y != 0) { n = n -32; x = y; } else x = (int)(i>>>32);
1815 y = x <<16; if (y != 0) { n = n -16; x = y; }
1816 y = x << 8; if (y != 0) { n = n - 8; x = y; }
1817 y = x << 4; if (y != 0) { n = n - 4; x = y; }
1818 y = x << 2; if (y != 0) { n = n - 2; x = y; }
1819 return n - ((x << 1) >>> 31);
1820 }
1821
1822 /**
1823 * Returns the number of one-bits in the two's complement binary
1824 * representation of the specified {@code long} value. This function is
1825 * sometimes referred to as the <i>population count</i>.
1826 *
1827 * @param i the value whose bits are to be counted
1828 * @return the number of one-bits in the two's complement binary
1829 * representation of the specified {@code long} value.
1830 * @since 1.5
1831 */
1832 @HotSpotIntrinsicCandidate
1833 public static int bitCount(long i) {
1834 // HD, Figure 5-2
1835 i = i - ((i >>> 1) & 0x5555555555555555L);
1836 i = (i & 0x3333333333333333L) + ((i >>> 2) & 0x3333333333333333L);
1837 i = (i + (i >>> 4)) & 0x0f0f0f0f0f0f0f0fL;
1838 i = i + (i >>> 8);
1839 i = i + (i >>> 16);
1840 i = i + (i >>> 32);
1841 return (int)i & 0x7f;
1842 }
1843
1844 /**
1845 * Returns the value obtained by rotating the two's complement binary
1846 * representation of the specified {@code long} value left by the
1847 * specified number of bits. (Bits shifted out of the left hand, or
1848 * high-order, side reenter on the right, or low-order.)
1849 *
1850 * <p>Note that left rotation with a negative distance is equivalent to
1851 * right rotation: {@code rotateLeft(val, -distance) == rotateRight(val,
1852 * distance)}. Note also that rotation by any multiple of 64 is a
1853 * no-op, so all but the last six bits of the rotation distance can be
1854 * ignored, even if the distance is negative: {@code rotateLeft(val,
1855 * distance) == rotateLeft(val, distance & 0x3F)}.
1856 *
1857 * @param i the value whose bits are to be rotated left
1858 * @param distance the number of bit positions to rotate left
1859 * @return the value obtained by rotating the two's complement binary
1860 * representation of the specified {@code long} value left by the
1861 * specified number of bits.
1862 * @since 1.5
1863 */
1864 public static long rotateLeft(long i, int distance) {
1865 return (i << distance) | (i >>> -distance);
1866 }
1867
1868 /**
1869 * Returns the value obtained by rotating the two's complement binary
1870 * representation of the specified {@code long} value right by the
1871 * specified number of bits. (Bits shifted out of the right hand, or
1872 * low-order, side reenter on the left, or high-order.)
1873 *
1874 * <p>Note that right rotation with a negative distance is equivalent to
1875 * left rotation: {@code rotateRight(val, -distance) == rotateLeft(val,
1876 * distance)}. Note also that rotation by any multiple of 64 is a
1877 * no-op, so all but the last six bits of the rotation distance can be
1878 * ignored, even if the distance is negative: {@code rotateRight(val,
1879 * distance) == rotateRight(val, distance & 0x3F)}.
1880 *
1881 * @param i the value whose bits are to be rotated right
1882 * @param distance the number of bit positions to rotate right
1883 * @return the value obtained by rotating the two's complement binary
1884 * representation of the specified {@code long} value right by the
1885 * specified number of bits.
1886 * @since 1.5
1887 */
1888 public static long rotateRight(long i, int distance) {
1889 return (i >>> distance) | (i << -distance);
1890 }
1891
1892 /**
1893 * Returns the value obtained by reversing the order of the bits in the
1894 * two's complement binary representation of the specified {@code long}
1895 * value.
1896 *
1897 * @param i the value to be reversed
1898 * @return the value obtained by reversing order of the bits in the
1899 * specified {@code long} value.
1900 * @since 1.5
1901 */
1902 public static long reverse(long i) {
1903 // HD, Figure 7-1
1904 i = (i & 0x5555555555555555L) << 1 | (i >>> 1) & 0x5555555555555555L;
1905 i = (i & 0x3333333333333333L) << 2 | (i >>> 2) & 0x3333333333333333L;
1906 i = (i & 0x0f0f0f0f0f0f0f0fL) << 4 | (i >>> 4) & 0x0f0f0f0f0f0f0f0fL;
1907 i = (i & 0x00ff00ff00ff00ffL) << 8 | (i >>> 8) & 0x00ff00ff00ff00ffL;
1908 i = (i << 48) | ((i & 0xffff0000L) << 16) |
1909 ((i >>> 16) & 0xffff0000L) | (i >>> 48);
1910 return i;
1911 }
1912
1913 /**
1914 * Returns the signum function of the specified {@code long} value. (The
1915 * return value is -1 if the specified value is negative; 0 if the
1916 * specified value is zero; and 1 if the specified value is positive.)
1917 *
1918 * @param i the value whose signum is to be computed
1919 * @return the signum function of the specified {@code long} value.
1920 * @since 1.5
1921 */
1922 public static int signum(long i) {
1923 // HD, Section 2-7
1924 return (int) ((i >> 63) | (-i >>> 63));
1925 }
1926
1927 /**
1928 * Returns the value obtained by reversing the order of the bytes in the
1929 * two's complement representation of the specified {@code long} value.
1930 *
1931 * @param i the value whose bytes are to be reversed
1932 * @return the value obtained by reversing the bytes in the specified
1933 * {@code long} value.
1934 * @since 1.5
1935 */
1936 @HotSpotIntrinsicCandidate
1937 public static long reverseBytes(long i) {
1938 i = (i & 0x00ff00ff00ff00ffL) << 8 | (i >>> 8) & 0x00ff00ff00ff00ffL;
1939 return (i << 48) | ((i & 0xffff0000L) << 16) |
1940 ((i >>> 16) & 0xffff0000L) | (i >>> 48);
1941 }
1942
1943 /**
1944 * Adds two {@code long} values together as per the + operator.
1945 *
1946 * @param a the first operand
1947 * @param b the second operand
1948 * @return the sum of {@code a} and {@code b}
1949 * @see java.util.function.BinaryOperator
1950 * @since 1.8
1951 */
1952 public static long sum(long a, long b) {
1953 return a + b;
1954 }
1955
1956 /**
1957 * Returns the greater of two {@code long} values
1958 * as if by calling {@link Math#max(long, long) Math.max}.
1959 *
1960 * @param a the first operand
1961 * @param b the second operand
1962 * @return the greater of {@code a} and {@code b}
1963 * @see java.util.function.BinaryOperator
1964 * @since 1.8
1965 */
1966 public static long max(long a, long b) {
1967 return Math.max(a, b);
1968 }
1969
1970 /**
1971 * Returns the smaller of two {@code long} values
1972 * as if by calling {@link Math#min(long, long) Math.min}.
1973 *
1974 * @param a the first operand
1975 * @param b the second operand
1976 * @return the smaller of {@code a} and {@code b}
1977 * @see java.util.function.BinaryOperator
1978 * @since 1.8
1979 */
1980 public static long min(long a, long b) {
1981 return Math.min(a, b);
1982 }
1983
1984 /** use serialVersionUID from JDK 1.0.2 for interoperability */
1985 @Native private static final long serialVersionUID = 4290774380558885855L;
1986 }