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.lang.invoke.Constable;
30 import java.lang.invoke.MethodHandles;
31 import java.math.*;
32 import java.util.Objects;
33 import jdk.internal.HotSpotIntrinsicCandidate;
34
35 import static java.lang.String.COMPACT_STRINGS;
36 import static java.lang.String.LATIN1;
37 import static java.lang.String.UTF16;
38
39 /**
40 * The {@code Long} class wraps a value of the primitive type {@code
41 * long} in an object. An object of type {@code Long} contains a
42 * single field whose type is {@code long}.
43 *
44 * <p> In addition, this class provides several methods for converting
45 * a {@code long} to a {@code String} and a {@code String} to a {@code
46 * long}, as well as other constants and methods useful when dealing
47 * with a {@code long}.
48 *
49 * <p>Implementation note: The implementations of the "bit twiddling"
50 * methods (such as {@link #highestOneBit(long) highestOneBit} and
51 * {@link #numberOfTrailingZeros(long) numberOfTrailingZeros}) are
52 * based on material from Henry S. Warren, Jr.'s <i>Hacker's
53 * Delight</i>, (Addison Wesley, 2002).
54 *
55 * @author Lee Boynton
56 * @author Arthur van Hoff
57 * @author Josh Bloch
58 * @author Joseph D. Darcy
59 * @since 1.0
60 */
61 public final class Long extends Number implements Comparable<Long>, Constable<Long> {
62 /**
63 * A constant holding the minimum value a {@code long} can
64 * have, -2<sup>63</sup>.
65 */
66 @Native public static final long MIN_VALUE = 0x8000000000000000L;
67
68 /**
69 * A constant holding the maximum value a {@code long} can
70 * have, 2<sup>63</sup>-1.
71 */
72 @Native public static final long MAX_VALUE = 0x7fffffffffffffffL;
73
74 /**
75 * The {@code Class} instance representing the primitive type
76 * {@code long}.
77 *
78 * @since 1.1
79 */
80 @SuppressWarnings("unchecked")
81 public static final Class<Long> TYPE = (Class<Long>) Class.getPrimitiveClass("long");
82
83 /**
84 * Returns a string representation of the first argument in the
85 * radix specified by the second argument.
86 *
87 * <p>If the radix is smaller than {@code Character.MIN_RADIX}
88 * or larger than {@code Character.MAX_RADIX}, then the radix
89 * {@code 10} is used instead.
90 *
91 * <p>If the first argument is negative, the first element of the
92 * result is the ASCII minus sign {@code '-'}
93 * ({@code '\u005Cu002d'}). If the first argument is not
94 * negative, no sign character appears in the result.
95 *
96 * <p>The remaining characters of the result represent the magnitude
97 * of the first argument. If the magnitude is zero, it is
98 * represented by a single zero character {@code '0'}
99 * ({@code '\u005Cu0030'}); otherwise, the first character of
100 * the representation of the magnitude will not be the zero
101 * character. The following ASCII characters are used as digits:
102 *
103 * <blockquote>
104 * {@code 0123456789abcdefghijklmnopqrstuvwxyz}
105 * </blockquote>
106 *
107 * These are {@code '\u005Cu0030'} through
108 * {@code '\u005Cu0039'} and {@code '\u005Cu0061'} through
109 * {@code '\u005Cu007a'}. If {@code radix} is
110 * <var>N</var>, then the first <var>N</var> of these characters
111 * are used as radix-<var>N</var> digits in the order shown. Thus,
112 * the digits for hexadecimal (radix 16) are
113 * {@code 0123456789abcdef}. If uppercase letters are
114 * desired, the {@link java.lang.String#toUpperCase()} method may
115 * be called on the result:
116 *
117 * <blockquote>
118 * {@code Long.toString(n, 16).toUpperCase()}
119 * </blockquote>
120 *
121 * @param i a {@code long} to be converted to a string.
122 * @param radix the radix to use in the string representation.
123 * @return a string representation of the argument in the specified radix.
124 * @see java.lang.Character#MAX_RADIX
125 * @see java.lang.Character#MIN_RADIX
126 */
127 public static String toString(long i, int radix) {
128 if (radix < Character.MIN_RADIX || radix > Character.MAX_RADIX)
129 radix = 10;
130 if (radix == 10)
131 return toString(i);
132
133 if (COMPACT_STRINGS) {
134 byte[] buf = new byte[65];
135 int charPos = 64;
136 boolean negative = (i < 0);
137
138 if (!negative) {
139 i = -i;
140 }
141
142 while (i <= -radix) {
143 buf[charPos--] = (byte)Integer.digits[(int)(-(i % radix))];
144 i = i / radix;
145 }
146 buf[charPos] = (byte)Integer.digits[(int)(-i)];
147
148 if (negative) {
149 buf[--charPos] = '-';
150 }
151 return StringLatin1.newString(buf, charPos, (65 - charPos));
152 }
153 return toStringUTF16(i, radix);
154 }
155
156 private static String toStringUTF16(long i, int radix) {
157 byte[] buf = new byte[65 * 2];
158 int charPos = 64;
159 boolean negative = (i < 0);
160 if (!negative) {
161 i = -i;
162 }
163 while (i <= -radix) {
164 StringUTF16.putChar(buf, charPos--, Integer.digits[(int)(-(i % radix))]);
165 i = i / radix;
166 }
167 StringUTF16.putChar(buf, charPos, Integer.digits[(int)(-i)]);
168 if (negative) {
169 StringUTF16.putChar(buf, --charPos, '-');
170 }
171 return StringUTF16.newString(buf, charPos, (65 - charPos));
172 }
173
174 /**
175 * Returns a string representation of the first argument as an
176 * unsigned integer value in the radix specified by the second
177 * argument.
178 *
179 * <p>If the radix is smaller than {@code Character.MIN_RADIX}
180 * or larger than {@code Character.MAX_RADIX}, then the radix
181 * {@code 10} is used instead.
182 *
183 * <p>Note that since the first argument is treated as an unsigned
184 * value, no leading sign character is printed.
185 *
186 * <p>If the magnitude is zero, it is represented by a single zero
187 * character {@code '0'} ({@code '\u005Cu0030'}); otherwise,
188 * the first character of the representation of the magnitude will
189 * not be the zero character.
190 *
191 * <p>The behavior of radixes and the characters used as digits
192 * are the same as {@link #toString(long, int) toString}.
193 *
194 * @param i an integer to be converted to an unsigned string.
195 * @param radix the radix to use in the string representation.
196 * @return an unsigned string representation of the argument in the specified radix.
197 * @see #toString(long, int)
198 * @since 1.8
199 */
200 public static String toUnsignedString(long i, int radix) {
201 if (i >= 0)
202 return toString(i, radix);
203 else {
204 switch (radix) {
205 case 2:
206 return toBinaryString(i);
207
208 case 4:
209 return toUnsignedString0(i, 2);
210
211 case 8:
212 return toOctalString(i);
213
214 case 10:
215 /*
216 * We can get the effect of an unsigned division by 10
217 * on a long value by first shifting right, yielding a
218 * positive value, and then dividing by 5. This
219 * allows the last digit and preceding digits to be
220 * isolated more quickly than by an initial conversion
221 * to BigInteger.
222 */
223 long quot = (i >>> 1) / 5;
224 long rem = i - quot * 10;
225 return toString(quot) + rem;
226
227 case 16:
228 return toHexString(i);
229
230 case 32:
231 return toUnsignedString0(i, 5);
232
233 default:
234 return toUnsignedBigInteger(i).toString(radix);
235 }
236 }
237 }
238
239 /**
240 * Return a BigInteger equal to the unsigned value of the
241 * argument.
242 */
243 private static BigInteger toUnsignedBigInteger(long i) {
244 if (i >= 0L)
245 return BigInteger.valueOf(i);
246 else {
247 int upper = (int) (i >>> 32);
248 int lower = (int) i;
249
250 // return (upper << 32) + lower
251 return (BigInteger.valueOf(Integer.toUnsignedLong(upper))).shiftLeft(32).
252 add(BigInteger.valueOf(Integer.toUnsignedLong(lower)));
253 }
254 }
255
256 /**
257 * Returns a string representation of the {@code long}
258 * argument as an unsigned integer in base 16.
259 *
260 * <p>The unsigned {@code long} value is the argument plus
261 * 2<sup>64</sup> if the argument is negative; otherwise, it is
262 * equal to the argument. This value is converted to a string of
263 * ASCII digits in hexadecimal (base 16) with no extra
264 * leading {@code 0}s.
265 *
266 * <p>The value of the argument can be recovered from the returned
267 * string {@code s} by calling {@link
268 * Long#parseUnsignedLong(String, int) Long.parseUnsignedLong(s,
269 * 16)}.
270 *
271 * <p>If the unsigned magnitude is zero, it is represented by a
272 * single zero character {@code '0'} ({@code '\u005Cu0030'});
273 * otherwise, the first character of the representation of the
274 * unsigned magnitude will not be the zero character. The
275 * following characters are used as hexadecimal digits:
276 *
277 * <blockquote>
278 * {@code 0123456789abcdef}
279 * </blockquote>
280 *
281 * These are the characters {@code '\u005Cu0030'} through
282 * {@code '\u005Cu0039'} and {@code '\u005Cu0061'} through
283 * {@code '\u005Cu0066'}. If uppercase letters are desired,
284 * the {@link java.lang.String#toUpperCase()} method may be called
285 * on the result:
286 *
287 * <blockquote>
288 * {@code Long.toHexString(n).toUpperCase()}
289 * </blockquote>
290 *
291 * @param i a {@code long} to be converted to a string.
292 * @return the string representation of the unsigned {@code long}
293 * value represented by the argument in hexadecimal
294 * (base 16).
295 * @see #parseUnsignedLong(String, int)
296 * @see #toUnsignedString(long, int)
297 * @since 1.0.2
298 */
299 public static String toHexString(long i) {
300 return toUnsignedString0(i, 4);
301 }
302
303 /**
304 * Returns a string representation of the {@code long}
305 * argument as an unsigned integer in base 8.
306 *
307 * <p>The unsigned {@code long} value is the argument plus
308 * 2<sup>64</sup> if the argument is negative; otherwise, it is
309 * equal to the argument. This value is converted to a string of
310 * ASCII digits in octal (base 8) with no extra leading
311 * {@code 0}s.
312 *
313 * <p>The value of the argument can be recovered from the returned
314 * string {@code s} by calling {@link
315 * Long#parseUnsignedLong(String, int) Long.parseUnsignedLong(s,
316 * 8)}.
317 *
318 * <p>If the unsigned magnitude is zero, it is represented by a
319 * single zero character {@code '0'} ({@code '\u005Cu0030'});
320 * otherwise, the first character of the representation of the
321 * unsigned magnitude will not be the zero character. The
322 * following characters are used as octal digits:
323 *
324 * <blockquote>
325 * {@code 01234567}
326 * </blockquote>
327 *
328 * These are the characters {@code '\u005Cu0030'} through
329 * {@code '\u005Cu0037'}.
330 *
331 * @param i a {@code long} to be converted to a string.
332 * @return the string representation of the unsigned {@code long}
333 * value represented by the argument in octal (base 8).
334 * @see #parseUnsignedLong(String, int)
335 * @see #toUnsignedString(long, int)
336 * @since 1.0.2
337 */
338 public static String toOctalString(long i) {
339 return toUnsignedString0(i, 3);
340 }
341
342 /**
343 * Returns a string representation of the {@code long}
344 * argument as an unsigned integer in base 2.
345 *
346 * <p>The unsigned {@code long} value is the argument plus
347 * 2<sup>64</sup> if the argument is negative; otherwise, it is
348 * equal to the argument. This value is converted to a string of
349 * ASCII digits in binary (base 2) with no extra leading
350 * {@code 0}s.
351 *
352 * <p>The value of the argument can be recovered from the returned
353 * string {@code s} by calling {@link
354 * Long#parseUnsignedLong(String, int) Long.parseUnsignedLong(s,
355 * 2)}.
356 *
357 * <p>If the unsigned magnitude is zero, it is represented by a
358 * single zero character {@code '0'} ({@code '\u005Cu0030'});
359 * otherwise, the first character of the representation of the
360 * unsigned magnitude will not be the zero character. The
361 * characters {@code '0'} ({@code '\u005Cu0030'}) and {@code
362 * '1'} ({@code '\u005Cu0031'}) are used as binary digits.
363 *
364 * @param i a {@code long} to be converted to a string.
365 * @return the string representation of the unsigned {@code long}
366 * value represented by the argument in binary (base 2).
367 * @see #parseUnsignedLong(String, int)
368 * @see #toUnsignedString(long, int)
369 * @since 1.0.2
370 */
371 public static String toBinaryString(long i) {
372 return toUnsignedString0(i, 1);
373 }
374
375 /**
376 * Format a long (treated as unsigned) into a String.
377 * @param val the value to format
378 * @param shift the log2 of the base to format in (4 for hex, 3 for octal, 1 for binary)
379 */
380 static String toUnsignedString0(long val, int shift) {
381 // assert shift > 0 && shift <=5 : "Illegal shift value";
382 int mag = Long.SIZE - Long.numberOfLeadingZeros(val);
383 int chars = Math.max(((mag + (shift - 1)) / shift), 1);
384 if (COMPACT_STRINGS) {
385 byte[] buf = new byte[chars];
386 formatUnsignedLong0(val, shift, buf, 0, chars);
387 return new String(buf, LATIN1);
388 } else {
389 byte[] buf = new byte[chars * 2];
390 formatUnsignedLong0UTF16(val, shift, buf, 0, chars);
391 return new String(buf, UTF16);
392 }
393 }
394
395 /**
396 * Format a long (treated as unsigned) into a character buffer. If
397 * {@code len} exceeds the formatted ASCII representation of {@code val},
398 * {@code buf} will be padded with leading zeroes.
399 *
400 * @param val the unsigned long to format
401 * @param shift the log2 of the base to format in (4 for hex, 3 for octal, 1 for binary)
402 * @param buf the character buffer to write to
403 * @param offset the offset in the destination buffer to start at
404 * @param len the number of characters to write
405 */
406
407 /** byte[]/LATIN1 version */
408 static void formatUnsignedLong0(long val, int shift, byte[] buf, int offset, int len) {
409 int charPos = offset + len;
410 int radix = 1 << shift;
411 int mask = radix - 1;
412 do {
413 buf[--charPos] = (byte)Integer.digits[((int) val) & mask];
414 val >>>= shift;
415 } while (charPos > offset);
416 }
417
418 /** byte[]/UTF16 version */
419 static void formatUnsignedLong0UTF16(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 StringUTF16.putChar(buf, --charPos, Integer.digits[((int) val) & mask]);
425 val >>>= shift;
426 } while (charPos > offset);
427 }
428
429 static String fastUUID(long lsb, long msb) {
430 if (COMPACT_STRINGS) {
431 byte[] buf = new byte[36];
432 formatUnsignedLong0(lsb, 4, buf, 24, 12);
433 formatUnsignedLong0(lsb >>> 48, 4, buf, 19, 4);
434 formatUnsignedLong0(msb, 4, buf, 14, 4);
435 formatUnsignedLong0(msb >>> 16, 4, buf, 9, 4);
436 formatUnsignedLong0(msb >>> 32, 4, buf, 0, 8);
437
438 buf[23] = '-';
439 buf[18] = '-';
440 buf[13] = '-';
441 buf[8] = '-';
442
443 return new String(buf, LATIN1);
444 } else {
445 byte[] buf = new byte[72];
446
447 formatUnsignedLong0UTF16(lsb, 4, buf, 24, 12);
448 formatUnsignedLong0UTF16(lsb >>> 48, 4, buf, 19, 4);
449 formatUnsignedLong0UTF16(msb, 4, buf, 14, 4);
450 formatUnsignedLong0UTF16(msb >>> 16, 4, buf, 9, 4);
451 formatUnsignedLong0UTF16(msb >>> 32, 4, buf, 0, 8);
452
453 StringUTF16.putChar(buf, 23, '-');
454 StringUTF16.putChar(buf, 18, '-');
455 StringUTF16.putChar(buf, 13, '-');
456 StringUTF16.putChar(buf, 8, '-');
457
458 return new String(buf, UTF16);
459 }
460 }
461
462 /**
463 * Returns a {@code String} object representing the specified
464 * {@code long}. The argument is converted to signed decimal
465 * representation and returned as a string, exactly as if the
466 * argument and the radix 10 were given as arguments to the {@link
467 * #toString(long, int)} method.
468 *
469 * @param i a {@code long} to be converted.
470 * @return a string representation of the argument in base 10.
471 */
472 public static String toString(long i) {
473 int size = stringSize(i);
474 if (COMPACT_STRINGS) {
475 byte[] buf = new byte[size];
476 getChars(i, size, buf);
477 return new String(buf, LATIN1);
478 } else {
479 byte[] buf = new byte[size * 2];
480 getCharsUTF16(i, size, buf);
481 return new String(buf, UTF16);
482 }
483 }
484
485 /**
486 * Returns a string representation of the argument as an unsigned
487 * decimal value.
488 *
489 * The argument is converted to unsigned decimal representation
490 * and returned as a string exactly as if the argument and radix
491 * 10 were given as arguments to the {@link #toUnsignedString(long,
492 * int)} method.
493 *
494 * @param i an integer to be converted to an unsigned string.
495 * @return an unsigned string representation of the argument.
496 * @see #toUnsignedString(long, int)
497 * @since 1.8
498 */
499 public static String toUnsignedString(long i) {
500 return toUnsignedString(i, 10);
501 }
502
503 /**
504 * Places characters representing the long i into the
505 * character array buf. The characters are placed into
506 * the buffer backwards starting with the least significant
507 * digit at the specified index (exclusive), and working
508 * backwards from there.
509 *
510 * @implNote This method converts positive inputs into negative
511 * values, to cover the Long.MIN_VALUE case. Converting otherwise
512 * (negative to positive) will expose -Long.MIN_VALUE that overflows
513 * long.
514 *
515 * @param i value to convert
516 * @param index next index, after the least significant digit
517 * @param buf target buffer, Latin1-encoded
518 * @return index of the most significant digit or minus sign, if present
519 */
520 static int getChars(long i, int index, byte[] buf) {
521 long q;
522 int r;
523 int charPos = index;
524
525 boolean negative = (i < 0);
526 if (!negative) {
527 i = -i;
528 }
529
530 // Get 2 digits/iteration using longs until quotient fits into an int
531 while (i <= Integer.MIN_VALUE) {
532 q = i / 100;
533 r = (int)((q * 100) - i);
534 i = q;
535 buf[--charPos] = Integer.DigitOnes[r];
536 buf[--charPos] = Integer.DigitTens[r];
537 }
538
539 // Get 2 digits/iteration using ints
540 int q2;
541 int i2 = (int)i;
542 while (i2 <= -100) {
543 q2 = i2 / 100;
544 r = (q2 * 100) - i2;
545 i2 = q2;
546 buf[--charPos] = Integer.DigitOnes[r];
547 buf[--charPos] = Integer.DigitTens[r];
548 }
549
550 // We know there are at most two digits left at this point.
551 q2 = i2 / 10;
552 r = (q2 * 10) - i2;
553 buf[--charPos] = (byte)('0' + r);
554
555 // Whatever left is the remaining digit.
556 if (q2 < 0) {
557 buf[--charPos] = (byte)('0' - q2);
558 }
559
560 if (negative) {
561 buf[--charPos] = (byte)'-';
562 }
563 return charPos;
564 }
565
566 /**
567 * This is a variant of {@link #getChars(long, int, byte[])}, but for
568 * UTF-16 coder.
569 *
570 * @param i value to convert
571 * @param index next index, after the least significant digit
572 * @param buf target buffer, UTF16-coded.
573 * @return index of the most significant digit or minus sign, if present
574 */
575 static int getCharsUTF16(long i, int index, byte[] buf) {
576 long q;
577 int r;
578 int charPos = index;
579
580 boolean negative = (i < 0);
581 if (!negative) {
582 i = -i;
583 }
584
585 // Get 2 digits/iteration using longs until quotient fits into an int
586 while (i <= Integer.MIN_VALUE) {
587 q = i / 100;
588 r = (int)((q * 100) - i);
589 i = q;
590 StringUTF16.putChar(buf, --charPos, Integer.DigitOnes[r]);
591 StringUTF16.putChar(buf, --charPos, Integer.DigitTens[r]);
592 }
593
594 // Get 2 digits/iteration using ints
595 int q2;
596 int i2 = (int)i;
597 while (i2 <= -100) {
598 q2 = i2 / 100;
599 r = (q2 * 100) - i2;
600 i2 = q2;
601 StringUTF16.putChar(buf, --charPos, Integer.DigitOnes[r]);
602 StringUTF16.putChar(buf, --charPos, Integer.DigitTens[r]);
603 }
604
605 // We know there are at most two digits left at this point.
606 q2 = i2 / 10;
607 r = (q2 * 10) - i2;
608 StringUTF16.putChar(buf, --charPos, '0' + r);
609
610 // Whatever left is the remaining digit.
611 if (q2 < 0) {
612 StringUTF16.putChar(buf, --charPos, '0' - q2);
613 }
614
615 if (negative) {
616 StringUTF16.putChar(buf, --charPos, '-');
617 }
618 return charPos;
619 }
620
621 /**
622 * Returns the string representation size for a given long value.
623 *
624 * @param x long value
625 * @return string size
626 *
627 * @implNote There are other ways to compute this: e.g. binary search,
628 * but values are biased heavily towards zero, and therefore linear search
629 * wins. The iteration results are also routinely inlined in the generated
630 * code after loop unrolling.
631 */
632 static int stringSize(long x) {
633 int d = 1;
634 if (x >= 0) {
635 d = 0;
636 x = -x;
637 }
638 long p = -10;
639 for (int i = 1; i < 19; i++) {
640 if (x > p)
641 return i + d;
642 p = 10 * p;
643 }
644 return 19 + d;
645 }
646
647 /**
648 * Parses the string argument as a signed {@code long} in the
649 * radix specified by the second argument. The characters in the
650 * string must all be digits of the specified radix (as determined
651 * by whether {@link java.lang.Character#digit(char, int)} returns
652 * a nonnegative value), except that the first character may be an
653 * ASCII minus sign {@code '-'} ({@code '\u005Cu002D'}) to
654 * indicate a negative value or an ASCII plus sign {@code '+'}
655 * ({@code '\u005Cu002B'}) to indicate a positive value. The
656 * resulting {@code long} value is returned.
657 *
658 * <p>Note that neither the character {@code L}
659 * ({@code '\u005Cu004C'}) nor {@code l}
660 * ({@code '\u005Cu006C'}) is permitted to appear at the end
661 * of the string as a type indicator, as would be permitted in
662 * Java programming language source code - except that either
663 * {@code L} or {@code l} may appear as a digit for a
664 * radix greater than or equal to 22.
665 *
666 * <p>An exception of type {@code NumberFormatException} is
667 * thrown if any of the following situations occurs:
668 * <ul>
669 *
670 * <li>The first argument is {@code null} or is a string of
671 * length zero.
672 *
673 * <li>The {@code radix} is either smaller than {@link
674 * java.lang.Character#MIN_RADIX} or larger than {@link
675 * java.lang.Character#MAX_RADIX}.
676 *
677 * <li>Any character of the string is not a digit of the specified
678 * radix, except that the first character may be a minus sign
679 * {@code '-'} ({@code '\u005Cu002d'}) or plus sign {@code
680 * '+'} ({@code '\u005Cu002B'}) provided that the string is
681 * longer than length 1.
682 *
683 * <li>The value represented by the string is not a value of type
684 * {@code long}.
685 * </ul>
686 *
687 * <p>Examples:
688 * <blockquote><pre>
689 * parseLong("0", 10) returns 0L
690 * parseLong("473", 10) returns 473L
691 * parseLong("+42", 10) returns 42L
692 * parseLong("-0", 10) returns 0L
693 * parseLong("-FF", 16) returns -255L
694 * parseLong("1100110", 2) returns 102L
695 * parseLong("99", 8) throws a NumberFormatException
696 * parseLong("Hazelnut", 10) throws a NumberFormatException
697 * parseLong("Hazelnut", 36) returns 1356099454469L
698 * </pre></blockquote>
699 *
700 * @param s the {@code String} containing the
701 * {@code long} representation to be parsed.
702 * @param radix the radix to be used while parsing {@code s}.
703 * @return the {@code long} represented by the string argument in
704 * the specified radix.
705 * @throws NumberFormatException if the string does not contain a
706 * parsable {@code long}.
707 */
708 public static long parseLong(String s, int radix)
709 throws NumberFormatException
710 {
711 if (s == null) {
712 throw new NumberFormatException("null");
713 }
714
715 if (radix < Character.MIN_RADIX) {
716 throw new NumberFormatException("radix " + radix +
717 " less than Character.MIN_RADIX");
718 }
719 if (radix > Character.MAX_RADIX) {
720 throw new NumberFormatException("radix " + radix +
721 " greater than Character.MAX_RADIX");
722 }
723
724 boolean negative = false;
725 int i = 0, len = s.length();
726 long limit = -Long.MAX_VALUE;
727
728 if (len > 0) {
729 char firstChar = s.charAt(0);
730 if (firstChar < '0') { // Possible leading "+" or "-"
731 if (firstChar == '-') {
732 negative = true;
733 limit = Long.MIN_VALUE;
734 } else if (firstChar != '+') {
735 throw NumberFormatException.forInputString(s);
736 }
737
738 if (len == 1) { // Cannot have lone "+" or "-"
739 throw NumberFormatException.forInputString(s);
740 }
741 i++;
742 }
743 long multmin = limit / radix;
744 long result = 0;
745 while (i < len) {
746 // Accumulating negatively avoids surprises near MAX_VALUE
747 int digit = Character.digit(s.charAt(i++),radix);
748 if (digit < 0 || result < multmin) {
749 throw NumberFormatException.forInputString(s);
750 }
751 result *= radix;
752 if (result < limit + digit) {
753 throw NumberFormatException.forInputString(s);
754 }
755 result -= digit;
756 }
757 return negative ? result : -result;
758 } else {
759 throw NumberFormatException.forInputString(s);
760 }
761 }
762
763 /**
764 * Parses the {@link CharSequence} argument as a signed {@code long} in
765 * the specified {@code radix}, beginning at the specified
766 * {@code beginIndex} and extending to {@code endIndex - 1}.
767 *
768 * <p>The method does not take steps to guard against the
769 * {@code CharSequence} being mutated while parsing.
770 *
771 * @param s the {@code CharSequence} containing the {@code long}
772 * representation to be parsed
773 * @param beginIndex the beginning index, inclusive.
774 * @param endIndex the ending index, exclusive.
775 * @param radix the radix to be used while parsing {@code s}.
776 * @return the signed {@code long} represented by the subsequence in
777 * the specified radix.
778 * @throws NullPointerException if {@code s} is null.
779 * @throws IndexOutOfBoundsException if {@code beginIndex} is
780 * negative, or if {@code beginIndex} is greater than
781 * {@code endIndex} or if {@code endIndex} is greater than
782 * {@code s.length()}.
783 * @throws NumberFormatException if the {@code CharSequence} does not
784 * contain a parsable {@code int} in the specified
785 * {@code radix}, or if {@code radix} is either smaller than
786 * {@link java.lang.Character#MIN_RADIX} or larger than
787 * {@link java.lang.Character#MAX_RADIX}.
788 * @since 9
789 */
790 public static long parseLong(CharSequence s, int beginIndex, int endIndex, int radix)
791 throws NumberFormatException {
792 s = Objects.requireNonNull(s);
793
794 if (beginIndex < 0 || beginIndex > endIndex || endIndex > s.length()) {
795 throw new IndexOutOfBoundsException();
796 }
797 if (radix < Character.MIN_RADIX) {
798 throw new NumberFormatException("radix " + radix +
799 " less than Character.MIN_RADIX");
800 }
801 if (radix > Character.MAX_RADIX) {
802 throw new NumberFormatException("radix " + radix +
803 " greater than Character.MAX_RADIX");
804 }
805
806 boolean negative = false;
807 int i = beginIndex;
808 long limit = -Long.MAX_VALUE;
809
810 if (i < endIndex) {
811 char firstChar = s.charAt(i);
812 if (firstChar < '0') { // Possible leading "+" or "-"
813 if (firstChar == '-') {
814 negative = true;
815 limit = Long.MIN_VALUE;
816 } else if (firstChar != '+') {
817 throw NumberFormatException.forCharSequence(s, beginIndex,
818 endIndex, i);
819 }
820 i++;
821 }
822 if (i >= endIndex) { // Cannot have lone "+", "-" or ""
823 throw NumberFormatException.forCharSequence(s, beginIndex,
824 endIndex, i);
825 }
826 long multmin = limit / radix;
827 long result = 0;
828 while (i < endIndex) {
829 // Accumulating negatively avoids surprises near MAX_VALUE
830 int digit = Character.digit(s.charAt(i), radix);
831 if (digit < 0 || result < multmin) {
832 throw NumberFormatException.forCharSequence(s, beginIndex,
833 endIndex, i);
834 }
835 result *= radix;
836 if (result < limit + digit) {
837 throw NumberFormatException.forCharSequence(s, beginIndex,
838 endIndex, i);
839 }
840 i++;
841 result -= digit;
842 }
843 return negative ? result : -result;
844 } else {
845 throw new NumberFormatException("");
846 }
847 }
848
849 /**
850 * Parses the string argument as a signed decimal {@code long}.
851 * The characters in the string must all be decimal digits, except
852 * that the first character may be an ASCII minus sign {@code '-'}
853 * ({@code \u005Cu002D'}) to indicate a negative value or an
854 * ASCII plus sign {@code '+'} ({@code '\u005Cu002B'}) to
855 * indicate a positive value. The resulting {@code long} value is
856 * returned, exactly as if the argument and the radix {@code 10}
857 * were given as arguments to the {@link
858 * #parseLong(java.lang.String, int)} method.
859 *
860 * <p>Note that neither the character {@code L}
861 * ({@code '\u005Cu004C'}) nor {@code l}
862 * ({@code '\u005Cu006C'}) is permitted to appear at the end
863 * of the string as a type indicator, as would be permitted in
864 * Java programming language source code.
865 *
866 * @param s a {@code String} containing the {@code long}
867 * representation to be parsed
868 * @return the {@code long} represented by the argument in
869 * decimal.
870 * @throws NumberFormatException if the string does not contain a
871 * parsable {@code long}.
872 */
873 public static long parseLong(String s) throws NumberFormatException {
874 return parseLong(s, 10);
875 }
876
877 /**
878 * Parses the string argument as an unsigned {@code long} in the
879 * radix specified by the second argument. An unsigned integer
880 * maps the values usually associated with negative numbers to
881 * positive numbers larger than {@code MAX_VALUE}.
882 *
883 * The characters in the string must all be digits of the
884 * specified radix (as determined by whether {@link
885 * java.lang.Character#digit(char, int)} returns a nonnegative
886 * value), except that the first character may be an ASCII plus
887 * sign {@code '+'} ({@code '\u005Cu002B'}). The resulting
888 * integer value is returned.
889 *
890 * <p>An exception of type {@code NumberFormatException} is
891 * thrown if any of the following situations occurs:
892 * <ul>
893 * <li>The first argument is {@code null} or is a string of
894 * length zero.
895 *
896 * <li>The radix is either smaller than
897 * {@link java.lang.Character#MIN_RADIX} or
898 * larger than {@link java.lang.Character#MAX_RADIX}.
899 *
900 * <li>Any character of the string is not a digit of the specified
901 * radix, except that the first character may be a plus sign
902 * {@code '+'} ({@code '\u005Cu002B'}) provided that the
903 * string is longer than length 1.
904 *
905 * <li>The value represented by the string is larger than the
906 * largest unsigned {@code long}, 2<sup>64</sup>-1.
907 *
908 * </ul>
909 *
910 *
911 * @param s the {@code String} containing the unsigned integer
912 * representation to be parsed
913 * @param radix the radix to be used while parsing {@code s}.
914 * @return the unsigned {@code long} represented by the string
915 * argument in the specified radix.
916 * @throws NumberFormatException if the {@code String}
917 * does not contain a parsable {@code long}.
918 * @since 1.8
919 */
920 public static long parseUnsignedLong(String s, int radix)
921 throws NumberFormatException {
922 if (s == null) {
923 throw new NumberFormatException("null");
924 }
925
926 int len = s.length();
927 if (len > 0) {
928 char firstChar = s.charAt(0);
929 if (firstChar == '-') {
930 throw new
931 NumberFormatException(String.format("Illegal leading minus sign " +
932 "on unsigned string %s.", s));
933 } else {
934 if (len <= 12 || // Long.MAX_VALUE in Character.MAX_RADIX is 13 digits
935 (radix == 10 && len <= 18) ) { // Long.MAX_VALUE in base 10 is 19 digits
936 return parseLong(s, radix);
937 }
938
939 // No need for range checks on len due to testing above.
940 long first = parseLong(s, 0, len - 1, radix);
941 int second = Character.digit(s.charAt(len - 1), radix);
942 if (second < 0) {
943 throw new NumberFormatException("Bad digit at end of " + s);
944 }
945 long result = first * radix + second;
946
947 /*
948 * Test leftmost bits of multiprecision extension of first*radix
949 * for overflow. The number of bits needed is defined by
950 * GUARD_BIT = ceil(log2(Character.MAX_RADIX)) + 1 = 7. Then
951 * int guard = radix*(int)(first >>> (64 - GUARD_BIT)) and
952 * overflow is tested by splitting guard in the ranges
953 * guard < 92, 92 <= guard < 128, and 128 <= guard, where
954 * 92 = 128 - Character.MAX_RADIX. Note that guard cannot take
955 * on a value which does not include a prime factor in the legal
956 * radix range.
957 */
958 int guard = radix * (int) (first >>> 57);
959 if (guard >= 128 ||
960 (result >= 0 && guard >= 128 - Character.MAX_RADIX)) {
961 /*
962 * For purposes of exposition, the programmatic statements
963 * below should be taken to be multi-precision, i.e., not
964 * subject to overflow.
965 *
966 * A) Condition guard >= 128:
967 * If guard >= 128 then first*radix >= 2^7 * 2^57 = 2^64
968 * hence always overflow.
969 *
970 * B) Condition guard < 92:
971 * Define left7 = first >>> 57.
972 * Given first = (left7 * 2^57) + (first & (2^57 - 1)) then
973 * result <= (radix*left7)*2^57 + radix*(2^57 - 1) + second.
974 * Thus if radix*left7 < 92, radix <= 36, and second < 36,
975 * then result < 92*2^57 + 36*(2^57 - 1) + 36 = 2^64 hence
976 * never overflow.
977 *
978 * C) Condition 92 <= guard < 128:
979 * first*radix + second >= radix*left7*2^57 + second
980 * so that first*radix + second >= 92*2^57 + 0 > 2^63
981 *
982 * D) Condition guard < 128:
983 * radix*first <= (radix*left7) * 2^57 + radix*(2^57 - 1)
984 * so
985 * radix*first + second <= (radix*left7) * 2^57 + radix*(2^57 - 1) + 36
986 * thus
987 * radix*first + second < 128 * 2^57 + 36*2^57 - radix + 36
988 * whence
989 * radix*first + second < 2^64 + 2^6*2^57 = 2^64 + 2^63
990 *
991 * E) Conditions C, D, and result >= 0:
992 * C and D combined imply the mathematical result
993 * 2^63 < first*radix + second < 2^64 + 2^63. The lower
994 * bound is therefore negative as a signed long, but the
995 * upper bound is too small to overflow again after the
996 * signed long overflows to positive above 2^64 - 1. Hence
997 * result >= 0 implies overflow given C and D.
998 */
999 throw new NumberFormatException(String.format("String value %s exceeds " +
1000 "range of unsigned long.", s));
1001 }
1002 return result;
1003 }
1004 } else {
1005 throw NumberFormatException.forInputString(s);
1006 }
1007 }
1008
1009 /**
1010 * Parses the {@link CharSequence} argument as an unsigned {@code long} in
1011 * the specified {@code radix}, beginning at the specified
1012 * {@code beginIndex} and extending to {@code endIndex - 1}.
1013 *
1014 * <p>The method does not take steps to guard against the
1015 * {@code CharSequence} being mutated while parsing.
1016 *
1017 * @param s the {@code CharSequence} containing the unsigned
1018 * {@code long} representation to be parsed
1019 * @param beginIndex the beginning index, inclusive.
1020 * @param endIndex the ending index, exclusive.
1021 * @param radix the radix to be used while parsing {@code s}.
1022 * @return the unsigned {@code long} represented by the subsequence in
1023 * the specified radix.
1024 * @throws NullPointerException if {@code s} is null.
1025 * @throws IndexOutOfBoundsException if {@code beginIndex} is
1026 * negative, or if {@code beginIndex} is greater than
1027 * {@code endIndex} or if {@code endIndex} is greater than
1028 * {@code s.length()}.
1029 * @throws NumberFormatException if the {@code CharSequence} does not
1030 * contain a parsable unsigned {@code long} in the specified
1031 * {@code radix}, or if {@code radix} is either smaller than
1032 * {@link java.lang.Character#MIN_RADIX} or larger than
1033 * {@link java.lang.Character#MAX_RADIX}.
1034 * @since 9
1035 */
1036 public static long parseUnsignedLong(CharSequence s, int beginIndex, int endIndex, int radix)
1037 throws NumberFormatException {
1038 s = Objects.requireNonNull(s);
1039
1040 if (beginIndex < 0 || beginIndex > endIndex || endIndex > s.length()) {
1041 throw new IndexOutOfBoundsException();
1042 }
1043 int start = beginIndex, len = endIndex - beginIndex;
1044
1045 if (len > 0) {
1046 char firstChar = s.charAt(start);
1047 if (firstChar == '-') {
1048 throw new NumberFormatException(String.format("Illegal leading minus sign " +
1049 "on unsigned string %s.", s.subSequence(start, start + len)));
1050 } else {
1051 if (len <= 12 || // Long.MAX_VALUE in Character.MAX_RADIX is 13 digits
1052 (radix == 10 && len <= 18) ) { // Long.MAX_VALUE in base 10 is 19 digits
1053 return parseLong(s, start, start + len, radix);
1054 }
1055
1056 // No need for range checks on end due to testing above.
1057 long first = parseLong(s, start, start + len - 1, radix);
1058 int second = Character.digit(s.charAt(start + len - 1), radix);
1059 if (second < 0) {
1060 throw new NumberFormatException("Bad digit at end of " +
1061 s.subSequence(start, start + len));
1062 }
1063 long result = first * radix + second;
1064
1065 /*
1066 * Test leftmost bits of multiprecision extension of first*radix
1067 * for overflow. The number of bits needed is defined by
1068 * GUARD_BIT = ceil(log2(Character.MAX_RADIX)) + 1 = 7. Then
1069 * int guard = radix*(int)(first >>> (64 - GUARD_BIT)) and
1070 * overflow is tested by splitting guard in the ranges
1071 * guard < 92, 92 <= guard < 128, and 128 <= guard, where
1072 * 92 = 128 - Character.MAX_RADIX. Note that guard cannot take
1073 * on a value which does not include a prime factor in the legal
1074 * radix range.
1075 */
1076 int guard = radix * (int) (first >>> 57);
1077 if (guard >= 128 ||
1078 (result >= 0 && guard >= 128 - Character.MAX_RADIX)) {
1079 /*
1080 * For purposes of exposition, the programmatic statements
1081 * below should be taken to be multi-precision, i.e., not
1082 * subject to overflow.
1083 *
1084 * A) Condition guard >= 128:
1085 * If guard >= 128 then first*radix >= 2^7 * 2^57 = 2^64
1086 * hence always overflow.
1087 *
1088 * B) Condition guard < 92:
1089 * Define left7 = first >>> 57.
1090 * Given first = (left7 * 2^57) + (first & (2^57 - 1)) then
1091 * result <= (radix*left7)*2^57 + radix*(2^57 - 1) + second.
1092 * Thus if radix*left7 < 92, radix <= 36, and second < 36,
1093 * then result < 92*2^57 + 36*(2^57 - 1) + 36 = 2^64 hence
1094 * never overflow.
1095 *
1096 * C) Condition 92 <= guard < 128:
1097 * first*radix + second >= radix*left7*2^57 + second
1098 * so that first*radix + second >= 92*2^57 + 0 > 2^63
1099 *
1100 * D) Condition guard < 128:
1101 * radix*first <= (radix*left7) * 2^57 + radix*(2^57 - 1)
1102 * so
1103 * radix*first + second <= (radix*left7) * 2^57 + radix*(2^57 - 1) + 36
1104 * thus
1105 * radix*first + second < 128 * 2^57 + 36*2^57 - radix + 36
1106 * whence
1107 * radix*first + second < 2^64 + 2^6*2^57 = 2^64 + 2^63
1108 *
1109 * E) Conditions C, D, and result >= 0:
1110 * C and D combined imply the mathematical result
1111 * 2^63 < first*radix + second < 2^64 + 2^63. The lower
1112 * bound is therefore negative as a signed long, but the
1113 * upper bound is too small to overflow again after the
1114 * signed long overflows to positive above 2^64 - 1. Hence
1115 * result >= 0 implies overflow given C and D.
1116 */
1117 throw new NumberFormatException(String.format("String value %s exceeds " +
1118 "range of unsigned long.", s.subSequence(start, start + len)));
1119 }
1120 return result;
1121 }
1122 } else {
1123 throw NumberFormatException.forInputString("");
1124 }
1125 }
1126
1127 /**
1128 * Parses the string argument as an unsigned decimal {@code long}. The
1129 * characters in the string must all be decimal digits, except
1130 * that the first character may be an ASCII plus sign {@code
1131 * '+'} ({@code '\u005Cu002B'}). The resulting integer value
1132 * is returned, exactly as if the argument and the radix 10 were
1133 * given as arguments to the {@link
1134 * #parseUnsignedLong(java.lang.String, int)} method.
1135 *
1136 * @param s a {@code String} containing the unsigned {@code long}
1137 * representation to be parsed
1138 * @return the unsigned {@code long} value represented by the decimal string argument
1139 * @throws NumberFormatException if the string does not contain a
1140 * parsable unsigned integer.
1141 * @since 1.8
1142 */
1143 public static long parseUnsignedLong(String s) throws NumberFormatException {
1144 return parseUnsignedLong(s, 10);
1145 }
1146
1147 /**
1148 * Returns a {@code Long} object holding the value
1149 * extracted from the specified {@code String} when parsed
1150 * with the radix given by the second argument. The first
1151 * argument is interpreted as representing a signed
1152 * {@code long} in the radix specified by the second
1153 * argument, exactly as if the arguments were given to the {@link
1154 * #parseLong(java.lang.String, int)} method. The result is a
1155 * {@code Long} object that represents the {@code long}
1156 * value specified by the string.
1157 *
1158 * <p>In other words, this method returns a {@code Long} object equal
1159 * to the value of:
1160 *
1161 * <blockquote>
1162 * {@code new Long(Long.parseLong(s, radix))}
1163 * </blockquote>
1164 *
1165 * @param s the string to be parsed
1166 * @param radix the radix to be used in interpreting {@code s}
1167 * @return a {@code Long} object holding the value
1168 * represented by the string argument in the specified
1169 * radix.
1170 * @throws NumberFormatException If the {@code String} does not
1171 * contain a parsable {@code long}.
1172 */
1173 public static Long valueOf(String s, int radix) throws NumberFormatException {
1174 return Long.valueOf(parseLong(s, radix));
1175 }
1176
1177 /**
1178 * Returns a {@code Long} object holding the value
1179 * of the specified {@code String}. The argument is
1180 * interpreted as representing a signed decimal {@code long},
1181 * exactly as if the argument were given to the {@link
1182 * #parseLong(java.lang.String)} method. The result is a
1183 * {@code Long} object that represents the integer value
1184 * specified by the string.
1185 *
1186 * <p>In other words, this method returns a {@code Long} object
1187 * equal to the value of:
1188 *
1189 * <blockquote>
1190 * {@code new Long(Long.parseLong(s))}
1191 * </blockquote>
1192 *
1193 * @param s the string to be parsed.
1194 * @return a {@code Long} object holding the value
1195 * represented by the string argument.
1196 * @throws NumberFormatException If the string cannot be parsed
1197 * as a {@code long}.
1198 */
1199 public static Long valueOf(String s) throws NumberFormatException
1200 {
1201 return Long.valueOf(parseLong(s, 10));
1202 }
1203
1204 private static class LongCache {
1205 private LongCache(){}
1206
1207 static final Long cache[] = new Long[-(-128) + 127 + 1];
1208
1209 static {
1210 for(int i = 0; i < cache.length; i++)
1211 cache[i] = new Long(i - 128);
1212 }
1213 }
1214
1215 /**
1216 * Returns a {@code Long} instance representing the specified
1217 * {@code long} value.
1218 * If a new {@code Long} instance is not required, this method
1219 * should generally be used in preference to the constructor
1220 * {@link #Long(long)}, as this method is likely to yield
1221 * significantly better space and time performance by caching
1222 * frequently requested values.
1223 *
1224 * Note that unlike the {@linkplain Integer#valueOf(int)
1225 * corresponding method} in the {@code Integer} class, this method
1226 * is <em>not</em> required to cache values within a particular
1227 * range.
1228 *
1229 * @param l a long value.
1230 * @return a {@code Long} instance representing {@code l}.
1231 * @since 1.5
1232 */
1233 @HotSpotIntrinsicCandidate
1234 public static Long valueOf(long l) {
1235 final int offset = 128;
1236 if (l >= -128 && l <= 127) { // will cache
1237 return LongCache.cache[(int)l + offset];
1238 }
1239 return new Long(l);
1240 }
1241
1242 /**
1243 * Decodes a {@code String} into a {@code Long}.
1244 * Accepts decimal, hexadecimal, and octal numbers given by the
1245 * following grammar:
1246 *
1247 * <blockquote>
1248 * <dl>
1249 * <dt><i>DecodableString:</i>
1250 * <dd><i>Sign<sub>opt</sub> DecimalNumeral</i>
1251 * <dd><i>Sign<sub>opt</sub></i> {@code 0x} <i>HexDigits</i>
1252 * <dd><i>Sign<sub>opt</sub></i> {@code 0X} <i>HexDigits</i>
1253 * <dd><i>Sign<sub>opt</sub></i> {@code #} <i>HexDigits</i>
1254 * <dd><i>Sign<sub>opt</sub></i> {@code 0} <i>OctalDigits</i>
1255 *
1256 * <dt><i>Sign:</i>
1257 * <dd>{@code -}
1258 * <dd>{@code +}
1259 * </dl>
1260 * </blockquote>
1261 *
1262 * <i>DecimalNumeral</i>, <i>HexDigits</i>, and <i>OctalDigits</i>
1263 * are as defined in section 3.10.1 of
1264 * <cite>The Java™ Language Specification</cite>,
1265 * except that underscores are not accepted between digits.
1266 *
1267 * <p>The sequence of characters following an optional
1268 * sign and/or radix specifier ("{@code 0x}", "{@code 0X}",
1269 * "{@code #}", or leading zero) is parsed as by the {@code
1270 * Long.parseLong} method with the indicated radix (10, 16, or 8).
1271 * This sequence of characters must represent a positive value or
1272 * a {@link NumberFormatException} will be thrown. The result is
1273 * negated if first character of the specified {@code String} is
1274 * the minus sign. No whitespace characters are permitted in the
1275 * {@code String}.
1276 *
1277 * @param nm the {@code String} to decode.
1278 * @return a {@code Long} object holding the {@code long}
1279 * value represented by {@code nm}
1280 * @throws NumberFormatException if the {@code String} does not
1281 * contain a parsable {@code long}.
1282 * @see java.lang.Long#parseLong(String, int)
1283 * @since 1.2
1284 */
1285 public static Long decode(String nm) throws NumberFormatException {
1286 int radix = 10;
1287 int index = 0;
1288 boolean negative = false;
1289 Long result;
1290
1291 if (nm.length() == 0)
1292 throw new NumberFormatException("Zero length string");
1293 char firstChar = nm.charAt(0);
1294 // Handle sign, if present
1295 if (firstChar == '-') {
1296 negative = true;
1297 index++;
1298 } else if (firstChar == '+')
1299 index++;
1300
1301 // Handle radix specifier, if present
1302 if (nm.startsWith("0x", index) || nm.startsWith("0X", index)) {
1303 index += 2;
1304 radix = 16;
1305 }
1306 else if (nm.startsWith("#", index)) {
1307 index ++;
1308 radix = 16;
1309 }
1310 else if (nm.startsWith("0", index) && nm.length() > 1 + index) {
1311 index ++;
1312 radix = 8;
1313 }
1314
1315 if (nm.startsWith("-", index) || nm.startsWith("+", index))
1316 throw new NumberFormatException("Sign character in wrong position");
1317
1318 try {
1319 result = Long.valueOf(nm.substring(index), radix);
1320 result = negative ? Long.valueOf(-result.longValue()) : result;
1321 } catch (NumberFormatException e) {
1322 // If number is Long.MIN_VALUE, we'll end up here. The next line
1323 // handles this case, and causes any genuine format error to be
1324 // rethrown.
1325 String constant = negative ? ("-" + nm.substring(index))
1326 : nm.substring(index);
1327 result = Long.valueOf(constant, radix);
1328 }
1329 return result;
1330 }
1331
1332 /**
1333 * The value of the {@code Long}.
1334 *
1335 * @serial
1336 */
1337 private final long value;
1338
1339 /**
1340 * Constructs a newly allocated {@code Long} object that
1341 * represents the specified {@code long} argument.
1342 *
1343 * @param value the value to be represented by the
1344 * {@code Long} object.
1345 *
1346 * @deprecated
1347 * It is rarely appropriate to use this constructor. The static factory
1348 * {@link #valueOf(long)} is generally a better choice, as it is
1349 * likely to yield significantly better space and time performance.
1350 */
1351 @Deprecated(since="9")
1352 public Long(long value) {
1353 this.value = value;
1354 }
1355
1356 /**
1357 * Constructs a newly allocated {@code Long} object that
1358 * represents the {@code long} value indicated by the
1359 * {@code String} parameter. The string is converted to a
1360 * {@code long} value in exactly the manner used by the
1361 * {@code parseLong} method for radix 10.
1362 *
1363 * @param s the {@code String} to be converted to a
1364 * {@code Long}.
1365 * @throws NumberFormatException if the {@code String} does not
1366 * contain a parsable {@code long}.
1367 *
1368 * @deprecated
1369 * It is rarely appropriate to use this constructor.
1370 * Use {@link #parseLong(String)} to convert a string to a
1371 * {@code long} primitive, or use {@link #valueOf(String)}
1372 * to convert a string to a {@code Long} object.
1373 */
1374 @Deprecated(since="9")
1375 public Long(String s) throws NumberFormatException {
1376 this.value = parseLong(s, 10);
1377 }
1378
1379 /**
1380 * Returns the value of this {@code Long} as a {@code byte} after
1381 * a narrowing primitive conversion.
1382 * @jls 5.1.3 Narrowing Primitive Conversions
1383 */
1384 public byte byteValue() {
1385 return (byte)value;
1386 }
1387
1388 /**
1389 * Returns the value of this {@code Long} as a {@code short} after
1390 * a narrowing primitive conversion.
1391 * @jls 5.1.3 Narrowing Primitive Conversions
1392 */
1393 public short shortValue() {
1394 return (short)value;
1395 }
1396
1397 /**
1398 * Returns the value of this {@code Long} as an {@code int} after
1399 * a narrowing primitive conversion.
1400 * @jls 5.1.3 Narrowing Primitive Conversions
1401 */
1402 public int intValue() {
1403 return (int)value;
1404 }
1405
1406 /**
1407 * Returns the value of this {@code Long} as a
1408 * {@code long} value.
1409 */
1410 @HotSpotIntrinsicCandidate
1411 public long longValue() {
1412 return value;
1413 }
1414
1415 /**
1416 * Returns the value of this {@code Long} as a {@code float} after
1417 * a widening primitive conversion.
1418 * @jls 5.1.2 Widening Primitive Conversions
1419 */
1420 public float floatValue() {
1421 return (float)value;
1422 }
1423
1424 /**
1425 * Returns the value of this {@code Long} as a {@code double}
1426 * after a widening primitive conversion.
1427 * @jls 5.1.2 Widening Primitive Conversions
1428 */
1429 public double doubleValue() {
1430 return (double)value;
1431 }
1432
1433 /**
1434 * Returns a {@code String} object representing this
1435 * {@code Long}'s value. The value is converted to signed
1436 * decimal representation and returned as a string, exactly as if
1437 * the {@code long} value were given as an argument to the
1438 * {@link java.lang.Long#toString(long)} method.
1439 *
1440 * @return a string representation of the value of this object in
1441 * base 10.
1442 */
1443 public String toString() {
1444 return toString(value);
1445 }
1446
1447 /**
1448 * Returns a hash code for this {@code Long}. The result is
1449 * the exclusive OR of the two halves of the primitive
1450 * {@code long} value held by this {@code Long}
1451 * object. That is, the hashcode is the value of the expression:
1452 *
1453 * <blockquote>
1454 * {@code (int)(this.longValue()^(this.longValue()>>>32))}
1455 * </blockquote>
1456 *
1457 * @return a hash code value for this object.
1458 */
1459 @Override
1460 public int hashCode() {
1461 return Long.hashCode(value);
1462 }
1463
1464 /**
1465 * Returns a hash code for a {@code long} value; compatible with
1466 * {@code Long.hashCode()}.
1467 *
1468 * @param value the value to hash
1469 * @return a hash code value for a {@code long} value.
1470 * @since 1.8
1471 */
1472 public static int hashCode(long value) {
1473 return (int)(value ^ (value >>> 32));
1474 }
1475
1476 /**
1477 * Compares this object to the specified object. The result is
1478 * {@code true} if and only if the argument is not
1479 * {@code null} and is a {@code Long} object that
1480 * contains the same {@code long} value as this object.
1481 *
1482 * @param obj the object to compare with.
1483 * @return {@code true} if the objects are the same;
1484 * {@code false} otherwise.
1485 */
1486 public boolean equals(Object obj) {
1487 if (obj instanceof Long) {
1488 return value == ((Long)obj).longValue();
1489 }
1490 return false;
1491 }
1492
1493 /**
1494 * Determines the {@code long} value of the system property
1495 * with the specified name.
1496 *
1497 * <p>The first argument is treated as the name of a system
1498 * property. System properties are accessible through the {@link
1499 * java.lang.System#getProperty(java.lang.String)} method. The
1500 * string value of this property is then interpreted as a {@code
1501 * long} value using the grammar supported by {@link Long#decode decode}
1502 * and a {@code Long} object representing this value is returned.
1503 *
1504 * <p>If there is no property with the specified name, if the
1505 * specified name is empty or {@code null}, or if the property
1506 * does not have the correct numeric format, then {@code null} is
1507 * returned.
1508 *
1509 * <p>In other words, this method returns a {@code Long} object
1510 * equal to the value of:
1511 *
1512 * <blockquote>
1513 * {@code getLong(nm, null)}
1514 * </blockquote>
1515 *
1516 * @param nm property name.
1517 * @return the {@code Long} value of the property.
1518 * @throws SecurityException for the same reasons as
1519 * {@link System#getProperty(String) System.getProperty}
1520 * @see java.lang.System#getProperty(java.lang.String)
1521 * @see java.lang.System#getProperty(java.lang.String, java.lang.String)
1522 */
1523 public static Long getLong(String nm) {
1524 return getLong(nm, null);
1525 }
1526
1527 /**
1528 * Determines the {@code long} value of the system property
1529 * with the specified name.
1530 *
1531 * <p>The first argument is treated as the name of a system
1532 * property. System properties are accessible through the {@link
1533 * java.lang.System#getProperty(java.lang.String)} method. The
1534 * string value of this property is then interpreted as a {@code
1535 * long} value using the grammar supported by {@link Long#decode decode}
1536 * and a {@code Long} object representing this value is returned.
1537 *
1538 * <p>The second argument is the default value. A {@code Long} object
1539 * that represents the value of the second argument is returned if there
1540 * is no property of the specified name, if the property does not have
1541 * the correct numeric format, or if the specified name is empty or null.
1542 *
1543 * <p>In other words, this method returns a {@code Long} object equal
1544 * to the value of:
1545 *
1546 * <blockquote>
1547 * {@code getLong(nm, new Long(val))}
1548 * </blockquote>
1549 *
1550 * but in practice it may be implemented in a manner such as:
1551 *
1552 * <blockquote><pre>
1553 * Long result = getLong(nm, null);
1554 * return (result == null) ? new Long(val) : result;
1555 * </pre></blockquote>
1556 *
1557 * to avoid the unnecessary allocation of a {@code Long} object when
1558 * the default value is not needed.
1559 *
1560 * @param nm property name.
1561 * @param val default value.
1562 * @return the {@code Long} value of the property.
1563 * @throws SecurityException for the same reasons as
1564 * {@link System#getProperty(String) System.getProperty}
1565 * @see java.lang.System#getProperty(java.lang.String)
1566 * @see java.lang.System#getProperty(java.lang.String, java.lang.String)
1567 */
1568 public static Long getLong(String nm, long val) {
1569 Long result = Long.getLong(nm, null);
1570 return (result == null) ? Long.valueOf(val) : result;
1571 }
1572
1573 /**
1574 * Returns the {@code long} value of the system property with
1575 * the specified name. The first argument is treated as the name
1576 * of a system property. System properties are accessible through
1577 * the {@link java.lang.System#getProperty(java.lang.String)}
1578 * method. The string value of this property is then interpreted
1579 * as a {@code long} value, as per the
1580 * {@link Long#decode decode} method, and a {@code Long} object
1581 * representing this value is returned; in summary:
1582 *
1583 * <ul>
1584 * <li>If the property value begins with the two ASCII characters
1585 * {@code 0x} or the ASCII character {@code #}, not followed by
1586 * a minus sign, then the rest of it is parsed as a hexadecimal integer
1587 * exactly as for the method {@link #valueOf(java.lang.String, int)}
1588 * with radix 16.
1589 * <li>If the property value begins with the ASCII character
1590 * {@code 0} followed by another character, it is parsed as
1591 * an octal integer exactly as by the method {@link
1592 * #valueOf(java.lang.String, int)} with radix 8.
1593 * <li>Otherwise the property value is parsed as a decimal
1594 * integer exactly as by the method
1595 * {@link #valueOf(java.lang.String, int)} with radix 10.
1596 * </ul>
1597 *
1598 * <p>Note that, in every case, neither {@code L}
1599 * ({@code '\u005Cu004C'}) nor {@code l}
1600 * ({@code '\u005Cu006C'}) is permitted to appear at the end
1601 * of the property value as a type indicator, as would be
1602 * permitted in Java programming language source code.
1603 *
1604 * <p>The second argument is the default value. The default value is
1605 * returned if there is no property of the specified name, if the
1606 * property does not have the correct numeric format, or if the
1607 * specified name is empty or {@code null}.
1608 *
1609 * @param nm property name.
1610 * @param val default value.
1611 * @return the {@code Long} value of the property.
1612 * @throws SecurityException for the same reasons as
1613 * {@link System#getProperty(String) System.getProperty}
1614 * @see System#getProperty(java.lang.String)
1615 * @see System#getProperty(java.lang.String, java.lang.String)
1616 */
1617 public static Long getLong(String nm, Long val) {
1618 String v = null;
1619 try {
1620 v = System.getProperty(nm);
1621 } catch (IllegalArgumentException | NullPointerException e) {
1622 }
1623 if (v != null) {
1624 try {
1625 return Long.decode(v);
1626 } catch (NumberFormatException e) {
1627 }
1628 }
1629 return val;
1630 }
1631
1632 /**
1633 * Compares two {@code Long} objects numerically.
1634 *
1635 * @param anotherLong the {@code Long} to be compared.
1636 * @return the value {@code 0} if this {@code Long} is
1637 * equal to the argument {@code Long}; a value less than
1638 * {@code 0} if this {@code Long} is numerically less
1639 * than the argument {@code Long}; and a value greater
1640 * than {@code 0} if this {@code Long} is numerically
1641 * greater than the argument {@code Long} (signed
1642 * comparison).
1643 * @since 1.2
1644 */
1645 public int compareTo(Long anotherLong) {
1646 return compare(this.value, anotherLong.value);
1647 }
1648
1649 /**
1650 * Compares two {@code long} values numerically.
1651 * The value returned is identical to what would be returned by:
1652 * <pre>
1653 * Long.valueOf(x).compareTo(Long.valueOf(y))
1654 * </pre>
1655 *
1656 * @param x the first {@code long} to compare
1657 * @param y the second {@code long} to compare
1658 * @return the value {@code 0} if {@code x == y};
1659 * a value less than {@code 0} if {@code x < y}; and
1660 * a value greater than {@code 0} if {@code x > y}
1661 * @since 1.7
1662 */
1663 public static int compare(long x, long y) {
1664 return (x < y) ? -1 : ((x == y) ? 0 : 1);
1665 }
1666
1667 /**
1668 * Compares two {@code long} values numerically treating the values
1669 * as unsigned.
1670 *
1671 * @param x the first {@code long} to compare
1672 * @param y the second {@code long} to compare
1673 * @return the value {@code 0} if {@code x == y}; a value less
1674 * than {@code 0} if {@code x < y} as unsigned values; and
1675 * a value greater than {@code 0} if {@code x > y} as
1676 * unsigned values
1677 * @since 1.8
1678 */
1679 public static int compareUnsigned(long x, long y) {
1680 return compare(x + MIN_VALUE, y + MIN_VALUE);
1681 }
1682
1683
1684 /**
1685 * Returns the unsigned quotient of dividing the first argument by
1686 * the second where each argument and the result is interpreted as
1687 * an unsigned value.
1688 *
1689 * <p>Note that in two's complement arithmetic, the three other
1690 * basic arithmetic operations of add, subtract, and multiply are
1691 * bit-wise identical if the two operands are regarded as both
1692 * being signed or both being unsigned. Therefore separate {@code
1693 * addUnsigned}, etc. methods are not provided.
1694 *
1695 * @param dividend the value to be divided
1696 * @param divisor the value doing the dividing
1697 * @return the unsigned quotient of the first argument divided by
1698 * the second argument
1699 * @see #remainderUnsigned
1700 * @since 1.8
1701 */
1702 public static long divideUnsigned(long dividend, long divisor) {
1703 if (divisor < 0L) { // signed comparison
1704 // Answer must be 0 or 1 depending on relative magnitude
1705 // of dividend and divisor.
1706 return (compareUnsigned(dividend, divisor)) < 0 ? 0L :1L;
1707 }
1708
1709 if (dividend > 0) // Both inputs non-negative
1710 return dividend/divisor;
1711 else {
1712 /*
1713 * For simple code, leveraging BigInteger. Longer and faster
1714 * code written directly in terms of operations on longs is
1715 * possible; see "Hacker's Delight" for divide and remainder
1716 * algorithms.
1717 */
1718 return toUnsignedBigInteger(dividend).
1719 divide(toUnsignedBigInteger(divisor)).longValue();
1720 }
1721 }
1722
1723 /**
1724 * Returns the unsigned remainder from dividing the first argument
1725 * by the second where each argument and the result is interpreted
1726 * as an unsigned value.
1727 *
1728 * @param dividend the value to be divided
1729 * @param divisor the value doing the dividing
1730 * @return the unsigned remainder of the first argument divided by
1731 * the second argument
1732 * @see #divideUnsigned
1733 * @since 1.8
1734 */
1735 public static long remainderUnsigned(long dividend, long divisor) {
1736 if (dividend > 0 && divisor > 0) { // signed comparisons
1737 return dividend % divisor;
1738 } else {
1739 if (compareUnsigned(dividend, divisor) < 0) // Avoid explicit check for 0 divisor
1740 return dividend;
1741 else
1742 return toUnsignedBigInteger(dividend).
1743 remainder(toUnsignedBigInteger(divisor)).longValue();
1744 }
1745 }
1746
1747 // Bit Twiddling
1748
1749 /**
1750 * The number of bits used to represent a {@code long} value in two's
1751 * complement binary form.
1752 *
1753 * @since 1.5
1754 */
1755 @Native public static final int SIZE = 64;
1756
1757 /**
1758 * The number of bytes used to represent a {@code long} value in two's
1759 * complement binary form.
1760 *
1761 * @since 1.8
1762 */
1763 public static final int BYTES = SIZE / Byte.SIZE;
1764
1765 /**
1766 * Returns a {@code long} value with at most a single one-bit, in the
1767 * position of the highest-order ("leftmost") one-bit in the specified
1768 * {@code long} value. Returns zero if the specified value has no
1769 * one-bits in its two's complement binary representation, that is, if it
1770 * is equal to zero.
1771 *
1772 * @param i the value whose highest one bit is to be computed
1773 * @return a {@code long} value with a single one-bit, in the position
1774 * of the highest-order one-bit in the specified value, or zero if
1775 * the specified value is itself equal to zero.
1776 * @since 1.5
1777 */
1778 public static long highestOneBit(long i) {
1779 // HD, Figure 3-1
1780 i |= (i >> 1);
1781 i |= (i >> 2);
1782 i |= (i >> 4);
1783 i |= (i >> 8);
1784 i |= (i >> 16);
1785 i |= (i >> 32);
1786 return i - (i >>> 1);
1787 }
1788
1789 /**
1790 * Returns a {@code long} value with at most a single one-bit, in the
1791 * position of the lowest-order ("rightmost") one-bit in the specified
1792 * {@code long} value. Returns zero if the specified value has no
1793 * one-bits in its two's complement binary representation, that is, if it
1794 * is equal to zero.
1795 *
1796 * @param i the value whose lowest one bit is to be computed
1797 * @return a {@code long} value with a single one-bit, in the position
1798 * of the lowest-order one-bit in the specified value, or zero if
1799 * the specified value is itself equal to zero.
1800 * @since 1.5
1801 */
1802 public static long lowestOneBit(long i) {
1803 // HD, Section 2-1
1804 return i & -i;
1805 }
1806
1807 /**
1808 * Returns the number of zero bits preceding the highest-order
1809 * ("leftmost") one-bit in the two's complement binary representation
1810 * of the specified {@code long} value. Returns 64 if the
1811 * specified value has no one-bits in its two's complement representation,
1812 * in other words if it is equal to zero.
1813 *
1814 * <p>Note that this method is closely related to the logarithm base 2.
1815 * For all positive {@code long} values x:
1816 * <ul>
1817 * <li>floor(log<sub>2</sub>(x)) = {@code 63 - numberOfLeadingZeros(x)}
1818 * <li>ceil(log<sub>2</sub>(x)) = {@code 64 - numberOfLeadingZeros(x - 1)}
1819 * </ul>
1820 *
1821 * @param i the value whose number of leading zeros is to be computed
1822 * @return the number of zero bits preceding the highest-order
1823 * ("leftmost") one-bit in the two's complement binary representation
1824 * of the specified {@code long} value, or 64 if the value
1825 * is equal to zero.
1826 * @since 1.5
1827 */
1828 @HotSpotIntrinsicCandidate
1829 public static int numberOfLeadingZeros(long i) {
1830 // HD, Figure 5-6
1831 if (i == 0)
1832 return 64;
1833 int n = 1;
1834 int x = (int)(i >>> 32);
1835 if (x == 0) { n += 32; x = (int)i; }
1836 if (x >>> 16 == 0) { n += 16; x <<= 16; }
1837 if (x >>> 24 == 0) { n += 8; x <<= 8; }
1838 if (x >>> 28 == 0) { n += 4; x <<= 4; }
1839 if (x >>> 30 == 0) { n += 2; x <<= 2; }
1840 n -= x >>> 31;
1841 return n;
1842 }
1843
1844 /**
1845 * Returns the number of zero bits following the lowest-order ("rightmost")
1846 * one-bit in the two's complement binary representation of the specified
1847 * {@code long} value. Returns 64 if the specified value has no
1848 * one-bits in its two's complement representation, in other words if it is
1849 * equal to zero.
1850 *
1851 * @param i the value whose number of trailing zeros is to be computed
1852 * @return the number of zero bits following the lowest-order ("rightmost")
1853 * one-bit in the two's complement binary representation of the
1854 * specified {@code long} value, or 64 if the value is equal
1855 * to zero.
1856 * @since 1.5
1857 */
1858 @HotSpotIntrinsicCandidate
1859 public static int numberOfTrailingZeros(long i) {
1860 // HD, Figure 5-14
1861 int x, y;
1862 if (i == 0) return 64;
1863 int n = 63;
1864 y = (int)i; if (y != 0) { n = n -32; x = y; } else x = (int)(i>>>32);
1865 y = x <<16; if (y != 0) { n = n -16; x = y; }
1866 y = x << 8; if (y != 0) { n = n - 8; x = y; }
1867 y = x << 4; if (y != 0) { n = n - 4; x = y; }
1868 y = x << 2; if (y != 0) { n = n - 2; x = y; }
1869 return n - ((x << 1) >>> 31);
1870 }
1871
1872 /**
1873 * Returns the number of one-bits in the two's complement binary
1874 * representation of the specified {@code long} value. This function is
1875 * sometimes referred to as the <i>population count</i>.
1876 *
1877 * @param i the value whose bits are to be counted
1878 * @return the number of one-bits in the two's complement binary
1879 * representation of the specified {@code long} value.
1880 * @since 1.5
1881 */
1882 @HotSpotIntrinsicCandidate
1883 public static int bitCount(long i) {
1884 // HD, Figure 5-2
1885 i = i - ((i >>> 1) & 0x5555555555555555L);
1886 i = (i & 0x3333333333333333L) + ((i >>> 2) & 0x3333333333333333L);
1887 i = (i + (i >>> 4)) & 0x0f0f0f0f0f0f0f0fL;
1888 i = i + (i >>> 8);
1889 i = i + (i >>> 16);
1890 i = i + (i >>> 32);
1891 return (int)i & 0x7f;
1892 }
1893
1894 /**
1895 * Returns the value obtained by rotating the two's complement binary
1896 * representation of the specified {@code long} value left by the
1897 * specified number of bits. (Bits shifted out of the left hand, or
1898 * high-order, side reenter on the right, or low-order.)
1899 *
1900 * <p>Note that left rotation with a negative distance is equivalent to
1901 * right rotation: {@code rotateLeft(val, -distance) == rotateRight(val,
1902 * distance)}. Note also that rotation by any multiple of 64 is a
1903 * no-op, so all but the last six bits of the rotation distance can be
1904 * ignored, even if the distance is negative: {@code rotateLeft(val,
1905 * distance) == rotateLeft(val, distance & 0x3F)}.
1906 *
1907 * @param i the value whose bits are to be rotated left
1908 * @param distance the number of bit positions to rotate left
1909 * @return the value obtained by rotating the two's complement binary
1910 * representation of the specified {@code long} value left by the
1911 * specified number of bits.
1912 * @since 1.5
1913 */
1914 public static long rotateLeft(long i, int distance) {
1915 return (i << distance) | (i >>> -distance);
1916 }
1917
1918 /**
1919 * Returns the value obtained by rotating the two's complement binary
1920 * representation of the specified {@code long} value right by the
1921 * specified number of bits. (Bits shifted out of the right hand, or
1922 * low-order, side reenter on the left, or high-order.)
1923 *
1924 * <p>Note that right rotation with a negative distance is equivalent to
1925 * left rotation: {@code rotateRight(val, -distance) == rotateLeft(val,
1926 * distance)}. Note also that rotation by any multiple of 64 is a
1927 * no-op, so all but the last six bits of the rotation distance can be
1928 * ignored, even if the distance is negative: {@code rotateRight(val,
1929 * distance) == rotateRight(val, distance & 0x3F)}.
1930 *
1931 * @param i the value whose bits are to be rotated right
1932 * @param distance the number of bit positions to rotate right
1933 * @return the value obtained by rotating the two's complement binary
1934 * representation of the specified {@code long} value right by the
1935 * specified number of bits.
1936 * @since 1.5
1937 */
1938 public static long rotateRight(long i, int distance) {
1939 return (i >>> distance) | (i << -distance);
1940 }
1941
1942 /**
1943 * Returns the value obtained by reversing the order of the bits in the
1944 * two's complement binary representation of the specified {@code long}
1945 * value.
1946 *
1947 * @param i the value to be reversed
1948 * @return the value obtained by reversing order of the bits in the
1949 * specified {@code long} value.
1950 * @since 1.5
1951 */
1952 public static long reverse(long i) {
1953 // HD, Figure 7-1
1954 i = (i & 0x5555555555555555L) << 1 | (i >>> 1) & 0x5555555555555555L;
1955 i = (i & 0x3333333333333333L) << 2 | (i >>> 2) & 0x3333333333333333L;
1956 i = (i & 0x0f0f0f0f0f0f0f0fL) << 4 | (i >>> 4) & 0x0f0f0f0f0f0f0f0fL;
1957
1958 return reverseBytes(i);
1959 }
1960
1961 /**
1962 * Returns the signum function of the specified {@code long} value. (The
1963 * return value is -1 if the specified value is negative; 0 if the
1964 * specified value is zero; and 1 if the specified value is positive.)
1965 *
1966 * @param i the value whose signum is to be computed
1967 * @return the signum function of the specified {@code long} value.
1968 * @since 1.5
1969 */
1970 public static int signum(long i) {
1971 // HD, Section 2-7
1972 return (int) ((i >> 63) | (-i >>> 63));
1973 }
1974
1975 /**
1976 * Returns the value obtained by reversing the order of the bytes in the
1977 * two's complement representation of the specified {@code long} value.
1978 *
1979 * @param i the value whose bytes are to be reversed
1980 * @return the value obtained by reversing the bytes in the specified
1981 * {@code long} value.
1982 * @since 1.5
1983 */
1984 @HotSpotIntrinsicCandidate
1985 public static long reverseBytes(long i) {
1986 i = (i & 0x00ff00ff00ff00ffL) << 8 | (i >>> 8) & 0x00ff00ff00ff00ffL;
1987 return (i << 48) | ((i & 0xffff0000L) << 16) |
1988 ((i >>> 16) & 0xffff0000L) | (i >>> 48);
1989 }
1990
1991 /**
1992 * Adds two {@code long} values together as per the + operator.
1993 *
1994 * @param a the first operand
1995 * @param b the second operand
1996 * @return the sum of {@code a} and {@code b}
1997 * @see java.util.function.BinaryOperator
1998 * @since 1.8
1999 */
2000 public static long sum(long a, long b) {
2001 return a + b;
2002 }
2003
2004 /**
2005 * Returns the greater of two {@code long} values
2006 * as if by calling {@link Math#max(long, long) Math.max}.
2007 *
2008 * @param a the first operand
2009 * @param b the second operand
2010 * @return the greater of {@code a} and {@code b}
2011 * @see java.util.function.BinaryOperator
2012 * @since 1.8
2013 */
2014 public static long max(long a, long b) {
2015 return Math.max(a, b);
2016 }
2017
2018 /**
2019 * Returns the smaller of two {@code long} values
2020 * as if by calling {@link Math#min(long, long) Math.min}.
2021 *
2022 * @param a the first operand
2023 * @param b the second operand
2024 * @return the smaller of {@code a} and {@code b}
2025 * @see java.util.function.BinaryOperator
2026 * @since 1.8
2027 */
2028 public static long min(long a, long b) {
2029 return Math.min(a, b);
2030 }
2031
2032 @Override
2033 public Long resolveConstant(MethodHandles.Lookup lookup) {
2034 return this;
2035 }
2036
2037 /** use serialVersionUID from JDK 1.0.2 for interoperability */
2038 @Native private static final long serialVersionUID = 4290774380558885855L;
2039 }