1 /*
2 * Copyright (c) 1994, 2016, 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 if (COMPACT_STRINGS) {
383 byte[] buf = new byte[chars];
384 formatUnsignedLong0(val, shift, buf, 0, chars);
385 return new String(buf, LATIN1);
386 } else {
387 byte[] buf = new byte[chars * 2];
388 formatUnsignedLong0UTF16(val, shift, buf, 0, chars);
389 return new String(buf, UTF16);
390 }
391 }
392
393 /**
394 * Format a long (treated as unsigned) into a character buffer. If
395 * {@code len} exceeds the formatted ASCII representation of {@code val},
396 * {@code buf} will be padded with leading zeroes.
397 *
398 * @param val the unsigned long to format
399 * @param shift the log2 of the base to format in (4 for hex, 3 for octal, 1 for binary)
400 * @param buf the character buffer to write to
401 * @param offset the offset in the destination buffer to start at
402 * @param len the number of characters to write
403 */
404
405 /** byte[]/LATIN1 version */
406 static void formatUnsignedLong0(long val, int shift, byte[] buf, int offset, int len) {
407 int charPos = offset + len;
408 int radix = 1 << shift;
409 int mask = radix - 1;
410 do {
411 buf[--charPos] = (byte)Integer.digits[((int) val) & mask];
412 val >>>= shift;
413 } while (charPos > offset);
414 }
415
416 /** byte[]/UTF16 version */
417 static void formatUnsignedLong0UTF16(long val, int shift, byte[] buf, int offset, int len) {
418 int charPos = offset + len;
419 int radix = 1 << shift;
420 int mask = radix - 1;
421 do {
422 StringUTF16.putChar(buf, --charPos, Integer.digits[((int) val) & mask]);
423 val >>>= shift;
424 } while (charPos > offset);
425 }
426
427 static String fastUUID(long lsb, long msb) {
428 if (COMPACT_STRINGS) {
429 byte[] buf = new byte[36];
430 formatUnsignedLong0(lsb, 4, buf, 24, 12);
431 formatUnsignedLong0(lsb >>> 48, 4, buf, 19, 4);
432 formatUnsignedLong0(msb, 4, buf, 14, 4);
433 formatUnsignedLong0(msb >>> 16, 4, buf, 9, 4);
434 formatUnsignedLong0(msb >>> 32, 4, buf, 0, 8);
435
436 buf[23] = '-';
437 buf[18] = '-';
438 buf[13] = '-';
439 buf[8] = '-';
440
441 return new String(buf, LATIN1);
442 } else {
443 byte[] buf = new byte[72];
444
445 formatUnsignedLong0UTF16(lsb, 4, buf, 24, 12);
446 formatUnsignedLong0UTF16(lsb >>> 48, 4, buf, 19, 4);
447 formatUnsignedLong0UTF16(msb, 4, buf, 14, 4);
448 formatUnsignedLong0UTF16(msb >>> 16, 4, buf, 9, 4);
449 formatUnsignedLong0UTF16(msb >>> 32, 4, buf, 0, 8);
450
451 StringUTF16.putChar(buf, 23, '-');
452 StringUTF16.putChar(buf, 18, '-');
453 StringUTF16.putChar(buf, 13, '-');
454 StringUTF16.putChar(buf, 8, '-');
455
456 return new String(buf, UTF16);
457 }
458 }
459
460 /**
461 * Returns a {@code String} object representing the specified
462 * {@code long}. The argument is converted to signed decimal
463 * representation and returned as a string, exactly as if the
464 * argument and the radix 10 were given as arguments to the {@link
465 * #toString(long, int)} method.
466 *
467 * @param i a {@code long} to be converted.
468 * @return a string representation of the argument in base 10.
469 */
470 public static String toString(long i) {
471 int size = stringSize(i);
472 if (COMPACT_STRINGS) {
473 byte[] buf = new byte[size];
474 getChars(i, size, buf);
475 return new String(buf, LATIN1);
476 } else {
477 byte[] buf = new byte[size * 2];
478 getCharsUTF16(i, size, buf);
479 return new String(buf, UTF16);
480 }
481 }
482
483 /**
484 * Returns a string representation of the argument as an unsigned
485 * decimal value.
486 *
487 * The argument is converted to unsigned decimal representation
488 * and returned as a string exactly as if the argument and radix
489 * 10 were given as arguments to the {@link #toUnsignedString(long,
490 * int)} method.
491 *
492 * @param i an integer to be converted to an unsigned string.
493 * @return an unsigned string representation of the argument.
494 * @see #toUnsignedString(long, int)
495 * @since 1.8
496 */
497 public static String toUnsignedString(long i) {
498 return toUnsignedString(i, 10);
499 }
500
501 /**
502 * Places characters representing the long i into the
503 * character array buf. The characters are placed into
504 * the buffer backwards starting with the least significant
505 * digit at the specified index (exclusive), and working
506 * backwards from there.
507 *
508 * @implNote This method converts positive inputs into negative
509 * values, to cover the Long.MIN_VALUE case. Converting otherwise
510 * (negative to positive) will expose -Long.MIN_VALUE that overflows
511 * long.
512 *
513 * @param i value to convert
514 * @param index next index, after the least significant digit
515 * @param buf target buffer, Latin1-encoded
516 * @return index of the most significant digit or minus sign, if present
517 */
518 static int getChars(long i, int index, byte[] buf) {
519 long q;
520 int r;
521 int charPos = index;
522
523 boolean negative = (i < 0);
524 if (!negative) {
525 i = -i;
526 }
527
528 // Get 2 digits/iteration using longs until quotient fits into an int
529 while (i <= Integer.MIN_VALUE) {
530 q = i / 100;
531 r = (int)((q * 100) - i);
532 i = q;
533 buf[--charPos] = Integer.DigitOnes[r];
534 buf[--charPos] = Integer.DigitTens[r];
535 }
536
537 // Get 2 digits/iteration using ints
538 int q2;
539 int i2 = (int)i;
540 while (i2 <= -100) {
541 q2 = i2 / 100;
542 r = (q2 * 100) - i2;
543 i2 = q2;
544 buf[--charPos] = Integer.DigitOnes[r];
545 buf[--charPos] = Integer.DigitTens[r];
546 }
547
548 // We know there are at most two digits left at this point.
549 q2 = i2 / 10;
550 r = (q2 * 10) - i2;
551 buf[--charPos] = (byte)('0' + r);
552
553 // Whatever left is the remaining digit.
554 if (q2 < 0) {
555 buf[--charPos] = (byte)('0' - q2);
556 }
557
558 if (negative) {
559 buf[--charPos] = (byte)'-';
560 }
561 return charPos;
562 }
563
564 /**
565 * This is a variant of {@link #getChars(long, int, byte[])}, but for
566 * UTF-16 coder.
567 *
568 * @param i value to convert
569 * @param index next index, after the least significant digit
570 * @param buf target buffer, UTF16-coded.
571 * @return index of the most significant digit or minus sign, if present
572 */
573 static int getCharsUTF16(long i, int index, byte[] buf) {
574 long q;
575 int r;
576 int charPos = index;
577
578 boolean negative = (i < 0);
579 if (!negative) {
580 i = -i;
581 }
582
583 // Get 2 digits/iteration using longs until quotient fits into an int
584 while (i <= Integer.MIN_VALUE) {
585 q = i / 100;
586 r = (int)((q * 100) - i);
587 i = q;
588 StringUTF16.putChar(buf, --charPos, Integer.DigitOnes[r]);
589 StringUTF16.putChar(buf, --charPos, Integer.DigitTens[r]);
590 }
591
592 // Get 2 digits/iteration using ints
593 int q2;
594 int i2 = (int)i;
595 while (i2 <= -100) {
596 q2 = i2 / 100;
597 r = (q2 * 100) - i2;
598 i2 = q2;
599 StringUTF16.putChar(buf, --charPos, Integer.DigitOnes[r]);
600 StringUTF16.putChar(buf, --charPos, Integer.DigitTens[r]);
601 }
602
603 // We know there are at most two digits left at this point.
604 q2 = i2 / 10;
605 r = (q2 * 10) - i2;
606 StringUTF16.putChar(buf, --charPos, '0' + r);
607
608 // Whatever left is the remaining digit.
609 if (q2 < 0) {
610 StringUTF16.putChar(buf, --charPos, '0' - q2);
611 }
612
613 if (negative) {
614 StringUTF16.putChar(buf, --charPos, '-');
615 }
616 return charPos;
617 }
618
619 /**
620 * Returns the string representation size for a given long value.
621 *
622 * @param x long value
623 * @return string size
624 *
625 * @implNote There are other ways to compute this: e.g. binary search,
626 * but values are biased heavily towards zero, and therefore linear search
627 * wins. The iteration results are also routinely inlined in the generated
628 * code after loop unrolling.
629 */
630 static int stringSize(long x) {
631 int d = 1;
632 if (x >= 0) {
633 d = 0;
634 x = -x;
635 }
636 long p = -10;
637 for (int i = 1; i < 19; i++) {
638 if (x > p)
639 return i + d;
640 p = 10 * p;
641 }
642 return 19 + d;
643 }
644
645 /**
646 * Parses the string argument as a signed {@code long} in the
647 * radix specified by the second argument. The characters in the
648 * string must all be digits of the specified radix (as determined
649 * by whether {@link java.lang.Character#digit(char, int)} returns
650 * a nonnegative value), except that the first character may be an
651 * ASCII minus sign {@code '-'} ({@code '\u005Cu002D'}) to
652 * indicate a negative value or an ASCII plus sign {@code '+'}
653 * ({@code '\u005Cu002B'}) to indicate a positive value. The
654 * resulting {@code long} value is returned.
655 *
656 * <p>Note that neither the character {@code L}
657 * ({@code '\u005Cu004C'}) nor {@code l}
658 * ({@code '\u005Cu006C'}) is permitted to appear at the end
659 * of the string as a type indicator, as would be permitted in
660 * Java programming language source code - except that either
661 * {@code L} or {@code l} may appear as a digit for a
662 * radix greater than or equal to 22.
663 *
664 * <p>An exception of type {@code NumberFormatException} is
665 * thrown if any of the following situations occurs:
666 * <ul>
667 *
668 * <li>The first argument is {@code null} or is a string of
669 * length zero.
670 *
671 * <li>The {@code radix} is either smaller than {@link
672 * java.lang.Character#MIN_RADIX} or larger than {@link
673 * java.lang.Character#MAX_RADIX}.
674 *
675 * <li>Any character of the string is not a digit of the specified
676 * radix, except that the first character may be a minus sign
677 * {@code '-'} ({@code '\u005Cu002d'}) or plus sign {@code
678 * '+'} ({@code '\u005Cu002B'}) provided that the string is
679 * longer than length 1.
680 *
681 * <li>The value represented by the string is not a value of type
682 * {@code long}.
683 * </ul>
684 *
685 * <p>Examples:
686 * <blockquote><pre>
687 * parseLong("0", 10) returns 0L
688 * parseLong("473", 10) returns 473L
689 * parseLong("+42", 10) returns 42L
690 * parseLong("-0", 10) returns 0L
691 * parseLong("-FF", 16) returns -255L
692 * parseLong("1100110", 2) returns 102L
693 * parseLong("99", 8) throws a NumberFormatException
694 * parseLong("Hazelnut", 10) throws a NumberFormatException
695 * parseLong("Hazelnut", 36) returns 1356099454469L
696 * </pre></blockquote>
697 *
698 * @param s the {@code String} containing the
699 * {@code long} representation to be parsed.
700 * @param radix the radix to be used while parsing {@code s}.
701 * @return the {@code long} represented by the string argument in
702 * the specified radix.
703 * @throws NumberFormatException if the string does not contain a
704 * parsable {@code long}.
705 */
706 public static long parseLong(String s, int radix)
707 throws NumberFormatException
708 {
709 if (s == null) {
710 throw new NumberFormatException("null");
711 }
712
713 if (radix < Character.MIN_RADIX) {
714 throw new NumberFormatException("radix " + radix +
715 " less than Character.MIN_RADIX");
716 }
717 if (radix > Character.MAX_RADIX) {
718 throw new NumberFormatException("radix " + radix +
719 " greater than Character.MAX_RADIX");
720 }
721
722 boolean negative = false;
723 int i = 0, len = s.length();
724 long limit = -Long.MAX_VALUE;
725
726 if (len > 0) {
727 char firstChar = s.charAt(0);
728 if (firstChar < '0') { // Possible leading "+" or "-"
729 if (firstChar == '-') {
730 negative = true;
731 limit = Long.MIN_VALUE;
732 } else if (firstChar != '+') {
733 throw NumberFormatException.forInputString(s);
734 }
735
736 if (len == 1) { // Cannot have lone "+" or "-"
737 throw NumberFormatException.forInputString(s);
738 }
739 i++;
740 }
741 long multmin = limit / radix;
742 long result = 0;
743 while (i < len) {
744 // Accumulating negatively avoids surprises near MAX_VALUE
745 int digit = Character.digit(s.charAt(i++),radix);
746 if (digit < 0 || result < multmin) {
747 throw NumberFormatException.forInputString(s);
748 }
749 result *= radix;
750 if (result < limit + digit) {
751 throw NumberFormatException.forInputString(s);
752 }
753 result -= digit;
754 }
755 return negative ? result : -result;
756 } else {
757 throw NumberFormatException.forInputString(s);
758 }
759 }
760
761 /**
762 * Parses the {@link CharSequence} argument as a signed {@code long} in
763 * the specified {@code radix}, beginning at the specified
764 * {@code beginIndex} and extending to {@code endIndex - 1}.
765 *
766 * <p>The method does not take steps to guard against the
767 * {@code CharSequence} being mutated while parsing.
768 *
769 * @param s the {@code CharSequence} containing the {@code long}
770 * representation to be parsed
771 * @param beginIndex the beginning index, inclusive.
772 * @param endIndex the ending index, exclusive.
773 * @param radix the radix to be used while parsing {@code s}.
774 * @return the signed {@code long} represented by the subsequence in
775 * the specified radix.
776 * @throws NullPointerException if {@code s} is null.
777 * @throws IndexOutOfBoundsException if {@code beginIndex} is
778 * negative, or if {@code beginIndex} is greater than
779 * {@code endIndex} or if {@code endIndex} is greater than
780 * {@code s.length()}.
781 * @throws NumberFormatException if the {@code CharSequence} does not
782 * contain a parsable {@code int} in the specified
783 * {@code radix}, or if {@code radix} is either smaller than
784 * {@link java.lang.Character#MIN_RADIX} or larger than
785 * {@link java.lang.Character#MAX_RADIX}.
786 * @since 9
787 */
788 public static long parseLong(CharSequence s, int beginIndex, int endIndex, int radix)
789 throws NumberFormatException {
790 s = Objects.requireNonNull(s);
791
792 if (beginIndex < 0 || beginIndex > endIndex || endIndex > s.length()) {
793 throw new IndexOutOfBoundsException();
794 }
795 if (radix < Character.MIN_RADIX) {
796 throw new NumberFormatException("radix " + radix +
797 " less than Character.MIN_RADIX");
798 }
799 if (radix > Character.MAX_RADIX) {
800 throw new NumberFormatException("radix " + radix +
801 " greater than Character.MAX_RADIX");
802 }
803
804 boolean negative = false;
805 int i = beginIndex;
806 long limit = -Long.MAX_VALUE;
807
808 if (i < endIndex) {
809 char firstChar = s.charAt(i);
810 if (firstChar < '0') { // Possible leading "+" or "-"
811 if (firstChar == '-') {
812 negative = true;
813 limit = Long.MIN_VALUE;
814 } else if (firstChar != '+') {
815 throw NumberFormatException.forCharSequence(s, beginIndex,
816 endIndex, i);
817 }
818 i++;
819 }
820 if (i >= endIndex) { // Cannot have lone "+", "-" or ""
821 throw NumberFormatException.forCharSequence(s, beginIndex,
822 endIndex, i);
823 }
824 long multmin = limit / radix;
825 long result = 0;
826 while (i < endIndex) {
827 // Accumulating negatively avoids surprises near MAX_VALUE
828 int digit = Character.digit(s.charAt(i), radix);
829 if (digit < 0 || result < multmin) {
830 throw NumberFormatException.forCharSequence(s, beginIndex,
831 endIndex, i);
832 }
833 result *= radix;
834 if (result < limit + digit) {
835 throw NumberFormatException.forCharSequence(s, beginIndex,
836 endIndex, i);
837 }
838 i++;
839 result -= digit;
840 }
841 return negative ? result : -result;
842 } else {
843 throw new NumberFormatException("");
844 }
845 }
846
847 /**
848 * Parses the string argument as a signed decimal {@code long}.
849 * The characters in the string must all be decimal digits, except
850 * that the first character may be an ASCII minus sign {@code '-'}
851 * ({@code \u005Cu002D'}) to indicate a negative value or an
852 * ASCII plus sign {@code '+'} ({@code '\u005Cu002B'}) to
853 * indicate a positive value. The resulting {@code long} value is
854 * returned, exactly as if the argument and the radix {@code 10}
855 * were given as arguments to the {@link
856 * #parseLong(java.lang.String, int)} method.
857 *
858 * <p>Note that neither the character {@code L}
859 * ({@code '\u005Cu004C'}) nor {@code l}
860 * ({@code '\u005Cu006C'}) is permitted to appear at the end
861 * of the string as a type indicator, as would be permitted in
862 * Java programming language source code.
863 *
864 * @param s a {@code String} containing the {@code long}
865 * representation to be parsed
866 * @return the {@code long} represented by the argument in
867 * decimal.
868 * @throws NumberFormatException if the string does not contain a
869 * parsable {@code long}.
870 */
871 public static long parseLong(String s) throws NumberFormatException {
872 return parseLong(s, 10);
873 }
874
875 /**
876 * Parses the string argument as an unsigned {@code long} in the
877 * radix specified by the second argument. An unsigned integer
878 * maps the values usually associated with negative numbers to
879 * positive numbers larger than {@code MAX_VALUE}.
880 *
881 * The characters in the string must all be digits of the
882 * specified radix (as determined by whether {@link
883 * java.lang.Character#digit(char, int)} returns a nonnegative
884 * value), except that the first character may be an ASCII plus
885 * sign {@code '+'} ({@code '\u005Cu002B'}). The resulting
886 * integer value is returned.
887 *
888 * <p>An exception of type {@code NumberFormatException} is
889 * thrown if any of the following situations occurs:
890 * <ul>
891 * <li>The first argument is {@code null} or is a string of
892 * length zero.
893 *
894 * <li>The radix is either smaller than
895 * {@link java.lang.Character#MIN_RADIX} or
896 * larger than {@link java.lang.Character#MAX_RADIX}.
897 *
898 * <li>Any character of the string is not a digit of the specified
899 * radix, except that the first character may be a plus sign
900 * {@code '+'} ({@code '\u005Cu002B'}) provided that the
901 * string is longer than length 1.
902 *
903 * <li>The value represented by the string is larger than the
904 * largest unsigned {@code long}, 2<sup>64</sup>-1.
905 *
906 * </ul>
907 *
908 *
909 * @param s the {@code String} containing the unsigned integer
910 * representation to be parsed
911 * @param radix the radix to be used while parsing {@code s}.
912 * @return the unsigned {@code long} represented by the string
913 * argument in the specified radix.
914 * @throws NumberFormatException if the {@code String}
915 * does not contain a parsable {@code long}.
916 * @since 1.8
917 */
918 public static long parseUnsignedLong(String s, int radix)
919 throws NumberFormatException {
920 if (s == null) {
921 throw new NumberFormatException("null");
922 }
923
924 int len = s.length();
925 if (len > 0) {
926 char firstChar = s.charAt(0);
927 if (firstChar == '-') {
928 throw new
929 NumberFormatException(String.format("Illegal leading minus sign " +
930 "on unsigned string %s.", s));
931 } else {
932 if (len <= 12 || // Long.MAX_VALUE in Character.MAX_RADIX is 13 digits
933 (radix == 10 && len <= 18) ) { // Long.MAX_VALUE in base 10 is 19 digits
934 return parseLong(s, radix);
935 }
936
937 // No need for range checks on len due to testing above.
938 long first = parseLong(s, 0, len - 1, radix);
939 int second = Character.digit(s.charAt(len - 1), radix);
940 if (second < 0) {
941 throw new NumberFormatException("Bad digit at end of " + s);
942 }
943 long result = first * radix + second;
944
945 /*
946 * Test leftmost bits of multiprecision extension of first*radix
947 * for overflow. The number of bits needed is defined by
948 * GUARD_BIT = ceil(log2(Character.MAX_RADIX)) + 1 = 7. Then
949 * int guard = radix*(int)(first >>> (64 - GUARD_BIT)) and
950 * overflow is tested by splitting guard in the ranges
951 * guard < 92, 92 <= guard < 128, and 128 <= guard, where
952 * 92 = 128 - Character.MAX_RADIX. Note that guard cannot take
953 * on a value which does not include a prime factor in the legal
954 * radix range.
955 */
956 int guard = radix * (int) (first >>> 57);
957 if (guard >= 128 ||
958 (result >= 0 && guard >= 128 - Character.MAX_RADIX)) {
959 /*
960 * For purposes of exposition, the programmatic statements
961 * below should be taken to be multi-precision, i.e., not
962 * subject to overflow.
963 *
964 * A) Condition guard >= 128:
965 * If guard >= 128 then first*radix >= 2^7 * 2^57 = 2^64
966 * hence always overflow.
967 *
968 * B) Condition guard < 92:
969 * Define left7 = first >>> 57.
970 * Given first = (left7 * 2^57) + (first & (2^57 - 1)) then
971 * result <= (radix*left7)*2^57 + radix*(2^57 - 1) + second.
972 * Thus if radix*left7 < 92, radix <= 36, and second < 36,
973 * then result < 92*2^57 + 36*(2^57 - 1) + 36 = 2^64 hence
974 * never overflow.
975 *
976 * C) Condition 92 <= guard < 128:
977 * first*radix + second >= radix*left7*2^57 + second
978 * so that first*radix + second >= 92*2^57 + 0 > 2^63
979 *
980 * D) Condition guard < 128:
981 * radix*first <= (radix*left7) * 2^57 + radix*(2^57 - 1)
982 * so
983 * radix*first + second <= (radix*left7) * 2^57 + radix*(2^57 - 1) + 36
984 * thus
985 * radix*first + second < 128 * 2^57 + 36*2^57 - radix + 36
986 * whence
987 * radix*first + second < 2^64 + 2^6*2^57 = 2^64 + 2^63
988 *
989 * E) Conditions C, D, and result >= 0:
990 * C and D combined imply the mathematical result
991 * 2^63 < first*radix + second < 2^64 + 2^63. The lower
992 * bound is therefore negative as a signed long, but the
993 * upper bound is too small to overflow again after the
994 * signed long overflows to positive above 2^64 - 1. Hence
995 * result >= 0 implies overflow given C and D.
996 */
997 throw new NumberFormatException(String.format("String value %s exceeds " +
998 "range of unsigned long.", s));
999 }
1000 return result;
1001 }
1002 } else {
1003 throw NumberFormatException.forInputString(s);
1004 }
1005 }
1006
1007 /**
1008 * Parses the {@link CharSequence} argument as an unsigned {@code long} in
1009 * the specified {@code radix}, beginning at the specified
1010 * {@code beginIndex} and extending to {@code endIndex - 1}.
1011 *
1012 * <p>The method does not take steps to guard against the
1013 * {@code CharSequence} being mutated while parsing.
1014 *
1015 * @param s the {@code CharSequence} containing the unsigned
1016 * {@code long} representation to be parsed
1017 * @param beginIndex the beginning index, inclusive.
1018 * @param endIndex the ending index, exclusive.
1019 * @param radix the radix to be used while parsing {@code s}.
1020 * @return the unsigned {@code long} represented by the subsequence in
1021 * the specified radix.
1022 * @throws NullPointerException if {@code s} is null.
1023 * @throws IndexOutOfBoundsException if {@code beginIndex} is
1024 * negative, or if {@code beginIndex} is greater than
1025 * {@code endIndex} or if {@code endIndex} is greater than
1026 * {@code s.length()}.
1027 * @throws NumberFormatException if the {@code CharSequence} does not
1028 * contain a parsable unsigned {@code long} in the specified
1029 * {@code radix}, or if {@code radix} is either smaller than
1030 * {@link java.lang.Character#MIN_RADIX} or larger than
1031 * {@link java.lang.Character#MAX_RADIX}.
1032 * @since 9
1033 */
1034 public static long parseUnsignedLong(CharSequence s, int beginIndex, int endIndex, int radix)
1035 throws NumberFormatException {
1036 s = Objects.requireNonNull(s);
1037
1038 if (beginIndex < 0 || beginIndex > endIndex || endIndex > s.length()) {
1039 throw new IndexOutOfBoundsException();
1040 }
1041 int start = beginIndex, len = endIndex - beginIndex;
1042
1043 if (len > 0) {
1044 char firstChar = s.charAt(start);
1045 if (firstChar == '-') {
1046 throw new NumberFormatException(String.format("Illegal leading minus sign " +
1047 "on unsigned string %s.", s.subSequence(start, start + len)));
1048 } else {
1049 if (len <= 12 || // Long.MAX_VALUE in Character.MAX_RADIX is 13 digits
1050 (radix == 10 && len <= 18) ) { // Long.MAX_VALUE in base 10 is 19 digits
1051 return parseLong(s, start, start + len, radix);
1052 }
1053
1054 // No need for range checks on end due to testing above.
1055 long first = parseLong(s, start, start + len - 1, radix);
1056 int second = Character.digit(s.charAt(start + len - 1), radix);
1057 if (second < 0) {
1058 throw new NumberFormatException("Bad digit at end of " +
1059 s.subSequence(start, start + len));
1060 }
1061 long result = first * radix + second;
1062
1063 /*
1064 * Test leftmost bits of multiprecision extension of first*radix
1065 * for overflow. The number of bits needed is defined by
1066 * GUARD_BIT = ceil(log2(Character.MAX_RADIX)) + 1 = 7. Then
1067 * int guard = radix*(int)(first >>> (64 - GUARD_BIT)) and
1068 * overflow is tested by splitting guard in the ranges
1069 * guard < 92, 92 <= guard < 128, and 128 <= guard, where
1070 * 92 = 128 - Character.MAX_RADIX. Note that guard cannot take
1071 * on a value which does not include a prime factor in the legal
1072 * radix range.
1073 */
1074 int guard = radix * (int) (first >>> 57);
1075 if (guard >= 128 ||
1076 (result >= 0 && guard >= 128 - Character.MAX_RADIX)) {
1077 /*
1078 * For purposes of exposition, the programmatic statements
1079 * below should be taken to be multi-precision, i.e., not
1080 * subject to overflow.
1081 *
1082 * A) Condition guard >= 128:
1083 * If guard >= 128 then first*radix >= 2^7 * 2^57 = 2^64
1084 * hence always overflow.
1085 *
1086 * B) Condition guard < 92:
1087 * Define left7 = first >>> 57.
1088 * Given first = (left7 * 2^57) + (first & (2^57 - 1)) then
1089 * result <= (radix*left7)*2^57 + radix*(2^57 - 1) + second.
1090 * Thus if radix*left7 < 92, radix <= 36, and second < 36,
1091 * then result < 92*2^57 + 36*(2^57 - 1) + 36 = 2^64 hence
1092 * never overflow.
1093 *
1094 * C) Condition 92 <= guard < 128:
1095 * first*radix + second >= radix*left7*2^57 + second
1096 * so that first*radix + second >= 92*2^57 + 0 > 2^63
1097 *
1098 * D) Condition guard < 128:
1099 * radix*first <= (radix*left7) * 2^57 + radix*(2^57 - 1)
1100 * so
1101 * radix*first + second <= (radix*left7) * 2^57 + radix*(2^57 - 1) + 36
1102 * thus
1103 * radix*first + second < 128 * 2^57 + 36*2^57 - radix + 36
1104 * whence
1105 * radix*first + second < 2^64 + 2^6*2^57 = 2^64 + 2^63
1106 *
1107 * E) Conditions C, D, and result >= 0:
1108 * C and D combined imply the mathematical result
1109 * 2^63 < first*radix + second < 2^64 + 2^63. The lower
1110 * bound is therefore negative as a signed long, but the
1111 * upper bound is too small to overflow again after the
1112 * signed long overflows to positive above 2^64 - 1. Hence
1113 * result >= 0 implies overflow given C and D.
1114 */
1115 throw new NumberFormatException(String.format("String value %s exceeds " +
1116 "range of unsigned long.", s.subSequence(start, start + len)));
1117 }
1118 return result;
1119 }
1120 } else {
1121 throw NumberFormatException.forInputString("");
1122 }
1123 }
1124
1125 /**
1126 * Parses the string argument as an unsigned decimal {@code long}. The
1127 * characters in the string must all be decimal digits, except
1128 * that the first character may be an ASCII plus sign {@code
1129 * '+'} ({@code '\u005Cu002B'}). The resulting integer value
1130 * is returned, exactly as if the argument and the radix 10 were
1131 * given as arguments to the {@link
1132 * #parseUnsignedLong(java.lang.String, int)} method.
1133 *
1134 * @param s a {@code String} containing the unsigned {@code long}
1135 * representation to be parsed
1136 * @return the unsigned {@code long} value represented by the decimal string argument
1137 * @throws NumberFormatException if the string does not contain a
1138 * parsable unsigned integer.
1139 * @since 1.8
1140 */
1141 public static long parseUnsignedLong(String s) throws NumberFormatException {
1142 return parseUnsignedLong(s, 10);
1143 }
1144
1145 /**
1146 * Returns a {@code Long} object holding the value
1147 * extracted from the specified {@code String} when parsed
1148 * with the radix given by the second argument. The first
1149 * argument is interpreted as representing a signed
1150 * {@code long} in the radix specified by the second
1151 * argument, exactly as if the arguments were given to the {@link
1152 * #parseLong(java.lang.String, int)} method. The result is a
1153 * {@code Long} object that represents the {@code long}
1154 * value specified by the string.
1155 *
1156 * <p>In other words, this method returns a {@code Long} object equal
1157 * to the value of:
1158 *
1159 * <blockquote>
1160 * {@code new Long(Long.parseLong(s, radix))}
1161 * </blockquote>
1162 *
1163 * @param s the string to be parsed
1164 * @param radix the radix to be used in interpreting {@code s}
1165 * @return a {@code Long} object holding the value
1166 * represented by the string argument in the specified
1167 * radix.
1168 * @throws NumberFormatException If the {@code String} does not
1169 * contain a parsable {@code long}.
1170 */
1171 public static Long valueOf(String s, int radix) throws NumberFormatException {
1172 return Long.valueOf(parseLong(s, radix));
1173 }
1174
1175 /**
1176 * Returns a {@code Long} object holding the value
1177 * of the specified {@code String}. The argument is
1178 * interpreted as representing a signed decimal {@code long},
1179 * exactly as if the argument were given to the {@link
1180 * #parseLong(java.lang.String)} method. The result is a
1181 * {@code Long} object that represents the integer value
1182 * specified by the string.
1183 *
1184 * <p>In other words, this method returns a {@code Long} object
1185 * equal to the value of:
1186 *
1187 * <blockquote>
1188 * {@code new Long(Long.parseLong(s))}
1189 * </blockquote>
1190 *
1191 * @param s the string to be parsed.
1192 * @return a {@code Long} object holding the value
1193 * represented by the string argument.
1194 * @throws NumberFormatException If the string cannot be parsed
1195 * as a {@code long}.
1196 */
1197 public static Long valueOf(String s) throws NumberFormatException
1198 {
1199 return Long.valueOf(parseLong(s, 10));
1200 }
1201
1202 private static class LongCache {
1203 private LongCache(){}
1204
1205 static final Long cache[] = new Long[-(-128) + 127 + 1];
1206
1207 static {
1208 for(int i = 0; i < cache.length; i++)
1209 cache[i] = new Long(i - 128);
1210 }
1211 }
1212
1213 /**
1214 * Returns a {@code Long} instance representing the specified
1215 * {@code long} value.
1216 * If a new {@code Long} instance is not required, this method
1217 * should generally be used in preference to the constructor
1218 * {@link #Long(long)}, as this method is likely to yield
1219 * significantly better space and time performance by caching
1220 * frequently requested values.
1221 *
1222 * Note that unlike the {@linkplain Integer#valueOf(int)
1223 * corresponding method} in the {@code Integer} class, this method
1224 * is <em>not</em> required to cache values within a particular
1225 * range.
1226 *
1227 * @param l a long value.
1228 * @return a {@code Long} instance representing {@code l}.
1229 * @since 1.5
1230 */
1231 @HotSpotIntrinsicCandidate
1232 public static Long valueOf(long l) {
1233 final int offset = 128;
1234 if (l >= -128 && l <= 127) { // will cache
1235 return LongCache.cache[(int)l + offset];
1236 }
1237 return new Long(l);
1238 }
1239
1240 /**
1241 * Decodes a {@code String} into a {@code Long}.
1242 * Accepts decimal, hexadecimal, and octal numbers given by the
1243 * following grammar:
1244 *
1245 * <blockquote>
1246 * <dl>
1247 * <dt><i>DecodableString:</i>
1248 * <dd><i>Sign<sub>opt</sub> DecimalNumeral</i>
1249 * <dd><i>Sign<sub>opt</sub></i> {@code 0x} <i>HexDigits</i>
1250 * <dd><i>Sign<sub>opt</sub></i> {@code 0X} <i>HexDigits</i>
1251 * <dd><i>Sign<sub>opt</sub></i> {@code #} <i>HexDigits</i>
1252 * <dd><i>Sign<sub>opt</sub></i> {@code 0} <i>OctalDigits</i>
1253 *
1254 * <dt><i>Sign:</i>
1255 * <dd>{@code -}
1256 * <dd>{@code +}
1257 * </dl>
1258 * </blockquote>
1259 *
1260 * <i>DecimalNumeral</i>, <i>HexDigits</i>, and <i>OctalDigits</i>
1261 * are as defined in section 3.10.1 of
1262 * <cite>The Java™ Language Specification</cite>,
1263 * except that underscores are not accepted between digits.
1264 *
1265 * <p>The sequence of characters following an optional
1266 * sign and/or radix specifier ("{@code 0x}", "{@code 0X}",
1267 * "{@code #}", or leading zero) is parsed as by the {@code
1268 * Long.parseLong} method with the indicated radix (10, 16, or 8).
1269 * This sequence of characters must represent a positive value or
1270 * a {@link NumberFormatException} will be thrown. The result is
1271 * negated if first character of the specified {@code String} is
1272 * the minus sign. No whitespace characters are permitted in the
1273 * {@code String}.
1274 *
1275 * @param nm the {@code String} to decode.
1276 * @return a {@code Long} object holding the {@code long}
1277 * value represented by {@code nm}
1278 * @throws NumberFormatException if the {@code String} does not
1279 * contain a parsable {@code long}.
1280 * @see java.lang.Long#parseLong(String, int)
1281 * @since 1.2
1282 */
1283 public static Long decode(String nm) throws NumberFormatException {
1284 int radix = 10;
1285 int index = 0;
1286 boolean negative = false;
1287 Long result;
1288
1289 if (nm.length() == 0)
1290 throw new NumberFormatException("Zero length string");
1291 char firstChar = nm.charAt(0);
1292 // Handle sign, if present
1293 if (firstChar == '-') {
1294 negative = true;
1295 index++;
1296 } else if (firstChar == '+')
1297 index++;
1298
1299 // Handle radix specifier, if present
1300 if (nm.startsWith("0x", index) || nm.startsWith("0X", index)) {
1301 index += 2;
1302 radix = 16;
1303 }
1304 else if (nm.startsWith("#", index)) {
1305 index ++;
1306 radix = 16;
1307 }
1308 else if (nm.startsWith("0", index) && nm.length() > 1 + index) {
1309 index ++;
1310 radix = 8;
1311 }
1312
1313 if (nm.startsWith("-", index) || nm.startsWith("+", index))
1314 throw new NumberFormatException("Sign character in wrong position");
1315
1316 try {
1317 result = Long.valueOf(nm.substring(index), radix);
1318 result = negative ? Long.valueOf(-result.longValue()) : result;
1319 } catch (NumberFormatException e) {
1320 // If number is Long.MIN_VALUE, we'll end up here. The next line
1321 // handles this case, and causes any genuine format error to be
1322 // rethrown.
1323 String constant = negative ? ("-" + nm.substring(index))
1324 : nm.substring(index);
1325 result = Long.valueOf(constant, radix);
1326 }
1327 return result;
1328 }
1329
1330 /**
1331 * The value of the {@code Long}.
1332 *
1333 * @serial
1334 */
1335 private final long value;
1336
1337 /**
1338 * Constructs a newly allocated {@code Long} object that
1339 * represents the specified {@code long} argument.
1340 *
1341 * @param value the value to be represented by the
1342 * {@code Long} object.
1343 *
1344 * @deprecated
1345 * It is rarely appropriate to use this constructor. The static factory
1346 * {@link #valueOf(long)} is generally a better choice, as it is
1347 * likely to yield significantly better space and time performance.
1348 */
1349 @Deprecated(since="9")
1350 public Long(long value) {
1351 this.value = value;
1352 }
1353
1354 /**
1355 * Constructs a newly allocated {@code Long} object that
1356 * represents the {@code long} value indicated by the
1357 * {@code String} parameter. The string is converted to a
1358 * {@code long} value in exactly the manner used by the
1359 * {@code parseLong} method for radix 10.
1360 *
1361 * @param s the {@code String} to be converted to a
1362 * {@code Long}.
1363 * @throws NumberFormatException if the {@code String} does not
1364 * contain a parsable {@code long}.
1365 *
1366 * @deprecated
1367 * It is rarely appropriate to use this constructor.
1368 * Use {@link #parseLong(String)} to convert a string to a
1369 * {@code long} primitive, or use {@link #valueOf(String)}
1370 * to convert a string to a {@code Long} object.
1371 */
1372 @Deprecated(since="9")
1373 public Long(String s) throws NumberFormatException {
1374 this.value = parseLong(s, 10);
1375 }
1376
1377 /**
1378 * Returns the value of this {@code Long} as a {@code byte} after
1379 * a narrowing primitive conversion.
1380 * @jls 5.1.3 Narrowing Primitive Conversions
1381 */
1382 public byte byteValue() {
1383 return (byte)value;
1384 }
1385
1386 /**
1387 * Returns the value of this {@code Long} as a {@code short} after
1388 * a narrowing primitive conversion.
1389 * @jls 5.1.3 Narrowing Primitive Conversions
1390 */
1391 public short shortValue() {
1392 return (short)value;
1393 }
1394
1395 /**
1396 * Returns the value of this {@code Long} as an {@code int} after
1397 * a narrowing primitive conversion.
1398 * @jls 5.1.3 Narrowing Primitive Conversions
1399 */
1400 public int intValue() {
1401 return (int)value;
1402 }
1403
1404 /**
1405 * Returns the value of this {@code Long} as a
1406 * {@code long} value.
1407 */
1408 @HotSpotIntrinsicCandidate
1409 public long longValue() {
1410 return value;
1411 }
1412
1413 /**
1414 * Returns the value of this {@code Long} as a {@code float} after
1415 * a widening primitive conversion.
1416 * @jls 5.1.2 Widening Primitive Conversions
1417 */
1418 public float floatValue() {
1419 return (float)value;
1420 }
1421
1422 /**
1423 * Returns the value of this {@code Long} as a {@code double}
1424 * after a widening primitive conversion.
1425 * @jls 5.1.2 Widening Primitive Conversions
1426 */
1427 public double doubleValue() {
1428 return (double)value;
1429 }
1430
1431 /**
1432 * Returns a {@code String} object representing this
1433 * {@code Long}'s value. The value is converted to signed
1434 * decimal representation and returned as a string, exactly as if
1435 * the {@code long} value were given as an argument to the
1436 * {@link java.lang.Long#toString(long)} method.
1437 *
1438 * @return a string representation of the value of this object in
1439 * base 10.
1440 */
1441 public String toString() {
1442 return toString(value);
1443 }
1444
1445 /**
1446 * Returns a hash code for this {@code Long}. The result is
1447 * the exclusive OR of the two halves of the primitive
1448 * {@code long} value held by this {@code Long}
1449 * object. That is, the hashcode is the value of the expression:
1450 *
1451 * <blockquote>
1452 * {@code (int)(this.longValue()^(this.longValue()>>>32))}
1453 * </blockquote>
1454 *
1455 * @return a hash code value for this object.
1456 */
1457 @Override
1458 public int hashCode() {
1459 return Long.hashCode(value);
1460 }
1461
1462 /**
1463 * Returns a hash code for a {@code long} value; compatible with
1464 * {@code Long.hashCode()}.
1465 *
1466 * @param value the value to hash
1467 * @return a hash code value for a {@code long} value.
1468 * @since 1.8
1469 */
1470 public static int hashCode(long value) {
1471 return (int)(value ^ (value >>> 32));
1472 }
1473
1474 /**
1475 * Compares this object to the specified object. The result is
1476 * {@code true} if and only if the argument is not
1477 * {@code null} and is a {@code Long} object that
1478 * contains the same {@code long} value as this object.
1479 *
1480 * @param obj the object to compare with.
1481 * @return {@code true} if the objects are the same;
1482 * {@code false} otherwise.
1483 */
1484 public boolean equals(Object obj) {
1485 if (obj instanceof Long) {
1486 return value == ((Long)obj).longValue();
1487 }
1488 return false;
1489 }
1490
1491 /**
1492 * Determines the {@code long} value of the system property
1493 * with the specified name.
1494 *
1495 * <p>The first argument is treated as the name of a system
1496 * property. System properties are accessible through the {@link
1497 * java.lang.System#getProperty(java.lang.String)} method. The
1498 * string value of this property is then interpreted as a {@code
1499 * long} value using the grammar supported by {@link Long#decode decode}
1500 * and a {@code Long} object representing this value is returned.
1501 *
1502 * <p>If there is no property with the specified name, if the
1503 * specified name is empty or {@code null}, or if the property
1504 * does not have the correct numeric format, then {@code null} is
1505 * returned.
1506 *
1507 * <p>In other words, this method returns a {@code Long} object
1508 * equal to the value of:
1509 *
1510 * <blockquote>
1511 * {@code getLong(nm, null)}
1512 * </blockquote>
1513 *
1514 * @param nm property name.
1515 * @return the {@code Long} value of the property.
1516 * @throws SecurityException for the same reasons as
1517 * {@link System#getProperty(String) System.getProperty}
1518 * @see java.lang.System#getProperty(java.lang.String)
1519 * @see java.lang.System#getProperty(java.lang.String, java.lang.String)
1520 */
1521 public static Long getLong(String nm) {
1522 return getLong(nm, null);
1523 }
1524
1525 /**
1526 * Determines the {@code long} value of the system property
1527 * with the specified name.
1528 *
1529 * <p>The first argument is treated as the name of a system
1530 * property. System properties are accessible through the {@link
1531 * java.lang.System#getProperty(java.lang.String)} method. The
1532 * string value of this property is then interpreted as a {@code
1533 * long} value using the grammar supported by {@link Long#decode decode}
1534 * and a {@code Long} object representing this value is returned.
1535 *
1536 * <p>The second argument is the default value. A {@code Long} object
1537 * that represents the value of the second argument is returned if there
1538 * is no property of the specified name, if the property does not have
1539 * the correct numeric format, or if the specified name is empty or null.
1540 *
1541 * <p>In other words, this method returns a {@code Long} object equal
1542 * to the value of:
1543 *
1544 * <blockquote>
1545 * {@code getLong(nm, new Long(val))}
1546 * </blockquote>
1547 *
1548 * but in practice it may be implemented in a manner such as:
1549 *
1550 * <blockquote><pre>
1551 * Long result = getLong(nm, null);
1552 * return (result == null) ? new Long(val) : result;
1553 * </pre></blockquote>
1554 *
1555 * to avoid the unnecessary allocation of a {@code Long} object when
1556 * the default value is not needed.
1557 *
1558 * @param nm property name.
1559 * @param val default value.
1560 * @return the {@code Long} value of the property.
1561 * @throws SecurityException for the same reasons as
1562 * {@link System#getProperty(String) System.getProperty}
1563 * @see java.lang.System#getProperty(java.lang.String)
1564 * @see java.lang.System#getProperty(java.lang.String, java.lang.String)
1565 */
1566 public static Long getLong(String nm, long val) {
1567 Long result = Long.getLong(nm, null);
1568 return (result == null) ? Long.valueOf(val) : result;
1569 }
1570
1571 /**
1572 * Returns the {@code long} value of the system property with
1573 * the specified name. The first argument is treated as the name
1574 * of a system property. System properties are accessible through
1575 * the {@link java.lang.System#getProperty(java.lang.String)}
1576 * method. The string value of this property is then interpreted
1577 * as a {@code long} value, as per the
1578 * {@link Long#decode decode} method, and a {@code Long} object
1579 * representing this value is returned; in summary:
1580 *
1581 * <ul>
1582 * <li>If the property value begins with the two ASCII characters
1583 * {@code 0x} or the ASCII character {@code #}, not followed by
1584 * a minus sign, then the rest of it is parsed as a hexadecimal integer
1585 * exactly as for the method {@link #valueOf(java.lang.String, int)}
1586 * with radix 16.
1587 * <li>If the property value begins with the ASCII character
1588 * {@code 0} followed by another character, it is parsed as
1589 * an octal integer exactly as by the method {@link
1590 * #valueOf(java.lang.String, int)} with radix 8.
1591 * <li>Otherwise the property value is parsed as a decimal
1592 * integer exactly as by the method
1593 * {@link #valueOf(java.lang.String, int)} with radix 10.
1594 * </ul>
1595 *
1596 * <p>Note that, in every case, neither {@code L}
1597 * ({@code '\u005Cu004C'}) nor {@code l}
1598 * ({@code '\u005Cu006C'}) is permitted to appear at the end
1599 * of the property value as a type indicator, as would be
1600 * permitted in Java programming language source code.
1601 *
1602 * <p>The second argument is the default value. The default value is
1603 * returned if there is no property of the specified name, if the
1604 * property does not have the correct numeric format, or if the
1605 * specified name is empty or {@code null}.
1606 *
1607 * @param nm property name.
1608 * @param val default value.
1609 * @return the {@code Long} value of the property.
1610 * @throws SecurityException for the same reasons as
1611 * {@link System#getProperty(String) System.getProperty}
1612 * @see System#getProperty(java.lang.String)
1613 * @see System#getProperty(java.lang.String, java.lang.String)
1614 */
1615 public static Long getLong(String nm, Long val) {
1616 String v = null;
1617 try {
1618 v = System.getProperty(nm);
1619 } catch (IllegalArgumentException | NullPointerException e) {
1620 }
1621 if (v != null) {
1622 try {
1623 return Long.decode(v);
1624 } catch (NumberFormatException e) {
1625 }
1626 }
1627 return val;
1628 }
1629
1630 /**
1631 * Compares two {@code Long} objects numerically.
1632 *
1633 * @param anotherLong the {@code Long} to be compared.
1634 * @return the value {@code 0} if this {@code Long} is
1635 * equal to the argument {@code Long}; a value less than
1636 * {@code 0} if this {@code Long} is numerically less
1637 * than the argument {@code Long}; and a value greater
1638 * than {@code 0} if this {@code Long} is numerically
1639 * greater than the argument {@code Long} (signed
1640 * comparison).
1641 * @since 1.2
1642 */
1643 public int compareTo(Long anotherLong) {
1644 return compare(this.value, anotherLong.value);
1645 }
1646
1647 /**
1648 * Compares two {@code long} values numerically.
1649 * The value returned is identical to what would be returned by:
1650 * <pre>
1651 * Long.valueOf(x).compareTo(Long.valueOf(y))
1652 * </pre>
1653 *
1654 * @param x the first {@code long} to compare
1655 * @param y the second {@code long} to compare
1656 * @return the value {@code 0} if {@code x == y};
1657 * a value less than {@code 0} if {@code x < y}; and
1658 * a value greater than {@code 0} if {@code x > y}
1659 * @since 1.7
1660 */
1661 public static int compare(long x, long y) {
1662 return (x < y) ? -1 : ((x == y) ? 0 : 1);
1663 }
1664
1665 /**
1666 * Compares two {@code long} values numerically treating the values
1667 * as unsigned.
1668 *
1669 * @param x the first {@code long} to compare
1670 * @param y the second {@code long} to compare
1671 * @return the value {@code 0} if {@code x == y}; a value less
1672 * than {@code 0} if {@code x < y} as unsigned values; and
1673 * a value greater than {@code 0} if {@code x > y} as
1674 * unsigned values
1675 * @since 1.8
1676 */
1677 public static int compareUnsigned(long x, long y) {
1678 return compare(x + MIN_VALUE, y + MIN_VALUE);
1679 }
1680
1681
1682 /**
1683 * Returns the unsigned quotient of dividing the first argument by
1684 * the second where each argument and the result is interpreted as
1685 * an unsigned value.
1686 *
1687 * <p>Note that in two's complement arithmetic, the three other
1688 * basic arithmetic operations of add, subtract, and multiply are
1689 * bit-wise identical if the two operands are regarded as both
1690 * being signed or both being unsigned. Therefore separate {@code
1691 * addUnsigned}, etc. methods are not provided.
1692 *
1693 * @param dividend the value to be divided
1694 * @param divisor the value doing the dividing
1695 * @return the unsigned quotient of the first argument divided by
1696 * the second argument
1697 * @see #remainderUnsigned
1698 * @since 1.8
1699 */
1700 public static long divideUnsigned(long dividend, long divisor) {
1701 if (divisor < 0L) { // signed comparison
1702 // Answer must be 0 or 1 depending on relative magnitude
1703 // of dividend and divisor.
1704 return (compareUnsigned(dividend, divisor)) < 0 ? 0L :1L;
1705 }
1706
1707 if (dividend > 0) // Both inputs non-negative
1708 return dividend/divisor;
1709 else {
1710 /*
1711 * For simple code, leveraging BigInteger. Longer and faster
1712 * code written directly in terms of operations on longs is
1713 * possible; see "Hacker's Delight" for divide and remainder
1714 * algorithms.
1715 */
1716 return toUnsignedBigInteger(dividend).
1717 divide(toUnsignedBigInteger(divisor)).longValue();
1718 }
1719 }
1720
1721 /**
1722 * Returns the unsigned remainder from dividing the first argument
1723 * by the second where each argument and the result is interpreted
1724 * as an unsigned value.
1725 *
1726 * @param dividend the value to be divided
1727 * @param divisor the value doing the dividing
1728 * @return the unsigned remainder of the first argument divided by
1729 * the second argument
1730 * @see #divideUnsigned
1731 * @since 1.8
1732 */
1733 public static long remainderUnsigned(long dividend, long divisor) {
1734 if (dividend > 0 && divisor > 0) { // signed comparisons
1735 return dividend % divisor;
1736 } else {
1737 if (compareUnsigned(dividend, divisor) < 0) // Avoid explicit check for 0 divisor
1738 return dividend;
1739 else
1740 return toUnsignedBigInteger(dividend).
1741 remainder(toUnsignedBigInteger(divisor)).longValue();
1742 }
1743 }
1744
1745 // Bit Twiddling
1746
1747 /**
1748 * The number of bits used to represent a {@code long} value in two's
1749 * complement binary form.
1750 *
1751 * @since 1.5
1752 */
1753 @Native public static final int SIZE = 64;
1754
1755 /**
1756 * The number of bytes used to represent a {@code long} value in two's
1757 * complement binary form.
1758 *
1759 * @since 1.8
1760 */
1761 public static final int BYTES = SIZE / Byte.SIZE;
1762
1763 /**
1764 * Returns a {@code long} value with at most a single one-bit, in the
1765 * position of the highest-order ("leftmost") one-bit in the specified
1766 * {@code long} value. Returns zero if the specified value has no
1767 * one-bits in its two's complement binary representation, that is, if it
1768 * is equal to zero.
1769 *
1770 * @param i the value whose highest one bit is to be computed
1771 * @return a {@code long} value with a single one-bit, in the position
1772 * of the highest-order one-bit in the specified value, or zero if
1773 * the specified value is itself equal to zero.
1774 * @since 1.5
1775 */
1776 public static long highestOneBit(long i) {
1777 // HD, Figure 3-1
1778 i |= (i >> 1);
1779 i |= (i >> 2);
1780 i |= (i >> 4);
1781 i |= (i >> 8);
1782 i |= (i >> 16);
1783 i |= (i >> 32);
1784 return i - (i >>> 1);
1785 }
1786
1787 /**
1788 * Returns a {@code long} value with at most a single one-bit, in the
1789 * position of the lowest-order ("rightmost") one-bit in the specified
1790 * {@code long} value. Returns zero if the specified value has no
1791 * one-bits in its two's complement binary representation, that is, if it
1792 * is equal to zero.
1793 *
1794 * @param i the value whose lowest one bit is to be computed
1795 * @return a {@code long} value with a single one-bit, in the position
1796 * of the lowest-order one-bit in the specified value, or zero if
1797 * the specified value is itself equal to zero.
1798 * @since 1.5
1799 */
1800 public static long lowestOneBit(long i) {
1801 // HD, Section 2-1
1802 return i & -i;
1803 }
1804
1805 /**
1806 * Returns the number of zero bits preceding the highest-order
1807 * ("leftmost") one-bit in the two's complement binary representation
1808 * of the specified {@code long} value. Returns 64 if the
1809 * specified value has no one-bits in its two's complement representation,
1810 * in other words if it is equal to zero.
1811 *
1812 * <p>Note that this method is closely related to the logarithm base 2.
1813 * For all positive {@code long} values x:
1814 * <ul>
1815 * <li>floor(log<sub>2</sub>(x)) = {@code 63 - numberOfLeadingZeros(x)}
1816 * <li>ceil(log<sub>2</sub>(x)) = {@code 64 - numberOfLeadingZeros(x - 1)}
1817 * </ul>
1818 *
1819 * @param i the value whose number of leading zeros is to be computed
1820 * @return the number of zero bits preceding the highest-order
1821 * ("leftmost") one-bit in the two's complement binary representation
1822 * of the specified {@code long} value, or 64 if the value
1823 * is equal to zero.
1824 * @since 1.5
1825 */
1826 @HotSpotIntrinsicCandidate
1827 public static int numberOfLeadingZeros(long i) {
1828 // HD, Figure 5-6
1829 if (i == 0)
1830 return 64;
1831 int n = 1;
1832 int x = (int)(i >>> 32);
1833 if (x == 0) { n += 32; x = (int)i; }
1834 if (x >>> 16 == 0) { n += 16; x <<= 16; }
1835 if (x >>> 24 == 0) { n += 8; x <<= 8; }
1836 if (x >>> 28 == 0) { n += 4; x <<= 4; }
1837 if (x >>> 30 == 0) { n += 2; x <<= 2; }
1838 n -= x >>> 31;
1839 return n;
1840 }
1841
1842 /**
1843 * Returns the number of zero bits following the lowest-order ("rightmost")
1844 * one-bit in the two's complement binary representation of the specified
1845 * {@code long} value. Returns 64 if the specified value has no
1846 * one-bits in its two's complement representation, in other words if it is
1847 * equal to zero.
1848 *
1849 * @param i the value whose number of trailing zeros is to be computed
1850 * @return the number of zero bits following the lowest-order ("rightmost")
1851 * one-bit in the two's complement binary representation of the
1852 * specified {@code long} value, or 64 if the value is equal
1853 * to zero.
1854 * @since 1.5
1855 */
1856 @HotSpotIntrinsicCandidate
1857 public static int numberOfTrailingZeros(long i) {
1858 // HD, Figure 5-14
1859 int x, y;
1860 if (i == 0) return 64;
1861 int n = 63;
1862 y = (int)i; if (y != 0) { n = n -32; x = y; } else x = (int)(i>>>32);
1863 y = x <<16; if (y != 0) { n = n -16; x = y; }
1864 y = x << 8; if (y != 0) { n = n - 8; x = y; }
1865 y = x << 4; if (y != 0) { n = n - 4; x = y; }
1866 y = x << 2; if (y != 0) { n = n - 2; x = y; }
1867 return n - ((x << 1) >>> 31);
1868 }
1869
1870 /**
1871 * Returns the number of one-bits in the two's complement binary
1872 * representation of the specified {@code long} value. This function is
1873 * sometimes referred to as the <i>population count</i>.
1874 *
1875 * @param i the value whose bits are to be counted
1876 * @return the number of one-bits in the two's complement binary
1877 * representation of the specified {@code long} value.
1878 * @since 1.5
1879 */
1880 @HotSpotIntrinsicCandidate
1881 public static int bitCount(long i) {
1882 // HD, Figure 5-2
1883 i = i - ((i >>> 1) & 0x5555555555555555L);
1884 i = (i & 0x3333333333333333L) + ((i >>> 2) & 0x3333333333333333L);
1885 i = (i + (i >>> 4)) & 0x0f0f0f0f0f0f0f0fL;
1886 i = i + (i >>> 8);
1887 i = i + (i >>> 16);
1888 i = i + (i >>> 32);
1889 return (int)i & 0x7f;
1890 }
1891
1892 /**
1893 * Returns the value obtained by rotating the two's complement binary
1894 * representation of the specified {@code long} value left by the
1895 * specified number of bits. (Bits shifted out of the left hand, or
1896 * high-order, side reenter on the right, or low-order.)
1897 *
1898 * <p>Note that left rotation with a negative distance is equivalent to
1899 * right rotation: {@code rotateLeft(val, -distance) == rotateRight(val,
1900 * distance)}. Note also that rotation by any multiple of 64 is a
1901 * no-op, so all but the last six bits of the rotation distance can be
1902 * ignored, even if the distance is negative: {@code rotateLeft(val,
1903 * distance) == rotateLeft(val, distance & 0x3F)}.
1904 *
1905 * @param i the value whose bits are to be rotated left
1906 * @param distance the number of bit positions to rotate left
1907 * @return the value obtained by rotating the two's complement binary
1908 * representation of the specified {@code long} value left by the
1909 * specified number of bits.
1910 * @since 1.5
1911 */
1912 public static long rotateLeft(long i, int distance) {
1913 return (i << distance) | (i >>> -distance);
1914 }
1915
1916 /**
1917 * Returns the value obtained by rotating the two's complement binary
1918 * representation of the specified {@code long} value right by the
1919 * specified number of bits. (Bits shifted out of the right hand, or
1920 * low-order, side reenter on the left, or high-order.)
1921 *
1922 * <p>Note that right rotation with a negative distance is equivalent to
1923 * left rotation: {@code rotateRight(val, -distance) == rotateLeft(val,
1924 * distance)}. Note also that rotation by any multiple of 64 is a
1925 * no-op, so all but the last six bits of the rotation distance can be
1926 * ignored, even if the distance is negative: {@code rotateRight(val,
1927 * distance) == rotateRight(val, distance & 0x3F)}.
1928 *
1929 * @param i the value whose bits are to be rotated right
1930 * @param distance the number of bit positions to rotate right
1931 * @return the value obtained by rotating the two's complement binary
1932 * representation of the specified {@code long} value right by the
1933 * specified number of bits.
1934 * @since 1.5
1935 */
1936 public static long rotateRight(long i, int distance) {
1937 return (i >>> distance) | (i << -distance);
1938 }
1939
1940 /**
1941 * Returns the value obtained by reversing the order of the bits in the
1942 * two's complement binary representation of the specified {@code long}
1943 * value.
1944 *
1945 * @param i the value to be reversed
1946 * @return the value obtained by reversing order of the bits in the
1947 * specified {@code long} value.
1948 * @since 1.5
1949 */
1950 public static long reverse(long i) {
1951 // HD, Figure 7-1
1952 i = (i & 0x5555555555555555L) << 1 | (i >>> 1) & 0x5555555555555555L;
1953 i = (i & 0x3333333333333333L) << 2 | (i >>> 2) & 0x3333333333333333L;
1954 i = (i & 0x0f0f0f0f0f0f0f0fL) << 4 | (i >>> 4) & 0x0f0f0f0f0f0f0f0fL;
1955
1956 return reverseBytes(i);
1957 }
1958
1959 /**
1960 * Returns the signum function of the specified {@code long} value. (The
1961 * return value is -1 if the specified value is negative; 0 if the
1962 * specified value is zero; and 1 if the specified value is positive.)
1963 *
1964 * @param i the value whose signum is to be computed
1965 * @return the signum function of the specified {@code long} value.
1966 * @since 1.5
1967 */
1968 public static int signum(long i) {
1969 // HD, Section 2-7
1970 return (int) ((i >> 63) | (-i >>> 63));
1971 }
1972
1973 /**
1974 * Returns the value obtained by reversing the order of the bytes in the
1975 * two's complement representation of the specified {@code long} value.
1976 *
1977 * @param i the value whose bytes are to be reversed
1978 * @return the value obtained by reversing the bytes in the specified
1979 * {@code long} value.
1980 * @since 1.5
1981 */
1982 @HotSpotIntrinsicCandidate
1983 public static long reverseBytes(long i) {
1984 i = (i & 0x00ff00ff00ff00ffL) << 8 | (i >>> 8) & 0x00ff00ff00ff00ffL;
1985 return (i << 48) | ((i & 0xffff0000L) << 16) |
1986 ((i >>> 16) & 0xffff0000L) | (i >>> 48);
1987 }
1988
1989 /**
1990 * Adds two {@code long} values together as per the + operator.
1991 *
1992 * @param a the first operand
1993 * @param b the second operand
1994 * @return the sum of {@code a} and {@code b}
1995 * @see java.util.function.BinaryOperator
1996 * @since 1.8
1997 */
1998 public static long sum(long a, long b) {
1999 return a + b;
2000 }
2001
2002 /**
2003 * Returns the greater of two {@code long} values
2004 * as if by calling {@link Math#max(long, long) Math.max}.
2005 *
2006 * @param a the first operand
2007 * @param b the second operand
2008 * @return the greater of {@code a} and {@code b}
2009 * @see java.util.function.BinaryOperator
2010 * @since 1.8
2011 */
2012 public static long max(long a, long b) {
2013 return Math.max(a, b);
2014 }
2015
2016 /**
2017 * Returns the smaller of two {@code long} values
2018 * as if by calling {@link Math#min(long, long) Math.min}.
2019 *
2020 * @param a the first operand
2021 * @param b the second operand
2022 * @return the smaller of {@code a} and {@code b}
2023 * @see java.util.function.BinaryOperator
2024 * @since 1.8
2025 */
2026 public static long min(long a, long b) {
2027 return Math.min(a, b);
2028 }
2029
2030 /** use serialVersionUID from JDK 1.0.2 for interoperability */
2031 @Native private static final long serialVersionUID = 4290774380558885855L;
2032 }