1 /*
2 * Copyright (c) 1994, 2013, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 package java.lang;
27
28 import java.lang.annotation.Native;
29 import java.math.*;
30 import java.util.Objects;
31 import jdk.internal.HotSpotIntrinsicCandidate;
32
33
34 /**
35 * The {@code Long} class wraps a value of the primitive type {@code
36 * long} in an object. An object of type {@code Long} contains a
37 * single field whose type is {@code long}.
38 *
39 * <p> In addition, this class provides several methods for converting
40 * a {@code long} to a {@code String} and a {@code String} to a {@code
41 * long}, as well as other constants and methods useful when dealing
42 * with a {@code long}.
43 *
44 * <p>Implementation note: The implementations of the "bit twiddling"
45 * methods (such as {@link #highestOneBit(long) highestOneBit} and
46 * {@link #numberOfTrailingZeros(long) numberOfTrailingZeros}) are
47 * based on material from Henry S. Warren, Jr.'s <i>Hacker's
48 * Delight</i>, (Addison Wesley, 2002).
49 *
50 * @author Lee Boynton
51 * @author Arthur van Hoff
52 * @author Josh Bloch
53 * @author Joseph D. Darcy
54 * @since 1.0
55 */
56 public final class Long extends Number implements Comparable<Long> {
57 /**
58 * A constant holding the minimum value a {@code long} can
59 * have, -2<sup>63</sup>.
60 */
61 @Native public static final long MIN_VALUE = 0x8000000000000000L;
62
63 /**
64 * A constant holding the maximum value a {@code long} can
65 * have, 2<sup>63</sup>-1.
66 */
67 @Native public static final long MAX_VALUE = 0x7fffffffffffffffL;
68
69 /**
70 * The {@code Class} instance representing the primitive type
71 * {@code long}.
72 *
73 * @since 1.1
74 */
75 @SuppressWarnings("unchecked")
76 public static final Class<Long> TYPE = (Class<Long>) Class.getPrimitiveClass("long");
77
78 /**
79 * Zero {@code Long} constant.
80 */
81 private static final Long ZERO = new Long(0L);
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 char[] buf = new char[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--] = Integer.digits[(int)(-(i % radix))];
142 i = i / radix;
143 }
144 buf[charPos] = Integer.digits[(int)(-i)];
145
146 if (negative) {
147 buf[--charPos] = '-';
148 }
149
150 return new String(buf, charPos, (65 - charPos));
151 }
152
153 /**
154 * Returns a string representation of the first argument as an
155 * unsigned integer value in the radix specified by the second
156 * argument.
157 *
158 * <p>If the radix is smaller than {@code Character.MIN_RADIX}
159 * or larger than {@code Character.MAX_RADIX}, then the radix
160 * {@code 10} is used instead.
161 *
162 * <p>Note that since the first argument is treated as an unsigned
163 * value, no leading sign character is printed.
164 *
165 * <p>If the magnitude is zero, it is represented by a single zero
166 * character {@code '0'} ({@code '\u005Cu0030'}); otherwise,
167 * the first character of the representation of the magnitude will
168 * not be the zero character.
169 *
170 * <p>The behavior of radixes and the characters used as digits
171 * are the same as {@link #toString(long, int) toString}.
172 *
173 * @param i an integer to be converted to an unsigned string.
174 * @param radix the radix to use in the string representation.
175 * @return an unsigned string representation of the argument in the specified radix.
176 * @see #toString(long, int)
177 * @since 1.8
178 */
179 public static String toUnsignedString(long i, int radix) {
180 if (i >= 0)
181 return toString(i, radix);
182 else {
183 switch (radix) {
184 case 2:
185 return toBinaryString(i);
186
187 case 4:
188 return toUnsignedString0(i, 2);
189
190 case 8:
191 return toOctalString(i);
192
193 case 10:
194 /*
195 * We can get the effect of an unsigned division by 10
196 * on a long value by first shifting right, yielding a
197 * positive value, and then dividing by 5. This
198 * allows the last digit and preceding digits to be
199 * isolated more quickly than by an initial conversion
200 * to BigInteger.
201 */
202 long quot = (i >>> 1) / 5;
203 long rem = i - quot * 10;
204 return toString(quot) + rem;
205
206 case 16:
207 return toHexString(i);
208
209 case 32:
210 return toUnsignedString0(i, 5);
211
212 default:
213 return toUnsignedBigInteger(i).toString(radix);
214 }
215 }
216 }
217
218 /**
219 * Return a BigInteger equal to the unsigned value of the
220 * argument.
221 */
222 private static BigInteger toUnsignedBigInteger(long i) {
223 if (i >= 0L)
224 return BigInteger.valueOf(i);
225 else {
226 int upper = (int) (i >>> 32);
227 int lower = (int) i;
228
229 // return (upper << 32) + lower
230 return (BigInteger.valueOf(Integer.toUnsignedLong(upper))).shiftLeft(32).
231 add(BigInteger.valueOf(Integer.toUnsignedLong(lower)));
232 }
233 }
234
235 /**
236 * Returns a string representation of the {@code long}
237 * argument as an unsigned integer in base 16.
238 *
239 * <p>The unsigned {@code long} value is the argument plus
240 * 2<sup>64</sup> if the argument is negative; otherwise, it is
241 * equal to the argument. This value is converted to a string of
242 * ASCII digits in hexadecimal (base 16) with no extra
243 * leading {@code 0}s.
244 *
245 * <p>The value of the argument can be recovered from the returned
246 * string {@code s} by calling {@link
247 * Long#parseUnsignedLong(String, int) Long.parseUnsignedLong(s,
248 * 16)}.
249 *
250 * <p>If the unsigned magnitude is zero, it is represented by a
251 * single zero character {@code '0'} ({@code '\u005Cu0030'});
252 * otherwise, the first character of the representation of the
253 * unsigned magnitude will not be the zero character. The
254 * following characters are used as hexadecimal digits:
255 *
256 * <blockquote>
257 * {@code 0123456789abcdef}
258 * </blockquote>
259 *
260 * These are the characters {@code '\u005Cu0030'} through
261 * {@code '\u005Cu0039'} and {@code '\u005Cu0061'} through
262 * {@code '\u005Cu0066'}. If uppercase letters are desired,
263 * the {@link java.lang.String#toUpperCase()} method may be called
264 * on the result:
265 *
266 * <blockquote>
267 * {@code Long.toHexString(n).toUpperCase()}
268 * </blockquote>
269 *
270 * @param i a {@code long} to be converted to a string.
271 * @return the string representation of the unsigned {@code long}
272 * value represented by the argument in hexadecimal
273 * (base 16).
274 * @see #parseUnsignedLong(String, int)
275 * @see #toUnsignedString(long, int)
276 * @since 1.0.2
277 */
278 public static String toHexString(long i) {
279 return toUnsignedString0(i, 4);
280 }
281
282 /**
283 * Returns a string representation of the {@code long}
284 * argument as an unsigned integer in base 8.
285 *
286 * <p>The unsigned {@code long} value is the argument plus
287 * 2<sup>64</sup> if the argument is negative; otherwise, it is
288 * equal to the argument. This value is converted to a string of
289 * ASCII digits in octal (base 8) with no extra leading
290 * {@code 0}s.
291 *
292 * <p>The value of the argument can be recovered from the returned
293 * string {@code s} by calling {@link
294 * Long#parseUnsignedLong(String, int) Long.parseUnsignedLong(s,
295 * 8)}.
296 *
297 * <p>If the unsigned magnitude is zero, it is represented by a
298 * single zero character {@code '0'} ({@code '\u005Cu0030'});
299 * otherwise, the first character of the representation of the
300 * unsigned magnitude will not be the zero character. The
301 * following characters are used as octal digits:
302 *
303 * <blockquote>
304 * {@code 01234567}
305 * </blockquote>
306 *
307 * These are the characters {@code '\u005Cu0030'} through
308 * {@code '\u005Cu0037'}.
309 *
310 * @param i a {@code long} to be converted to a string.
311 * @return the string representation of the unsigned {@code long}
312 * value represented by the argument in octal (base 8).
313 * @see #parseUnsignedLong(String, int)
314 * @see #toUnsignedString(long, int)
315 * @since 1.0.2
316 */
317 public static String toOctalString(long i) {
318 return toUnsignedString0(i, 3);
319 }
320
321 /**
322 * Returns a string representation of the {@code long}
323 * argument as an unsigned integer in base 2.
324 *
325 * <p>The unsigned {@code long} value is the argument plus
326 * 2<sup>64</sup> if the argument is negative; otherwise, it is
327 * equal to the argument. This value is converted to a string of
328 * ASCII digits in binary (base 2) with no extra leading
329 * {@code 0}s.
330 *
331 * <p>The value of the argument can be recovered from the returned
332 * string {@code s} by calling {@link
333 * Long#parseUnsignedLong(String, int) Long.parseUnsignedLong(s,
334 * 2)}.
335 *
336 * <p>If the unsigned magnitude is zero, it is represented by a
337 * single zero character {@code '0'} ({@code '\u005Cu0030'});
338 * otherwise, the first character of the representation of the
339 * unsigned magnitude will not be the zero character. The
340 * characters {@code '0'} ({@code '\u005Cu0030'}) and {@code
341 * '1'} ({@code '\u005Cu0031'}) are used as binary digits.
342 *
343 * @param i a {@code long} to be converted to a string.
344 * @return the string representation of the unsigned {@code long}
345 * value represented by the argument in binary (base 2).
346 * @see #parseUnsignedLong(String, int)
347 * @see #toUnsignedString(long, int)
348 * @since 1.0.2
349 */
350 public static String toBinaryString(long i) {
351 return toUnsignedString0(i, 1);
352 }
353
354 /**
355 * Format a long (treated as unsigned) into a String.
356 * @param val the value to format
357 * @param shift the log2 of the base to format in (4 for hex, 3 for octal, 1 for binary)
358 */
359 static String toUnsignedString0(long val, int shift) {
360 // assert shift > 0 && shift <=5 : "Illegal shift value";
361 int mag = Long.SIZE - Long.numberOfLeadingZeros(val);
362 int chars = Math.max(((mag + (shift - 1)) / shift), 1);
363 char[] buf = new char[chars];
364
365 formatUnsignedLong(val, shift, buf, 0, chars);
366 return new String(buf, true);
367 }
368
369 /**
370 * Format a long (treated as unsigned) into a character buffer. If
371 * {@code len} exceeds the formatted ASCII representation of {@code val},
372 * {@code buf} will be padded with leading zeroes.
373 *
374 * @param val the unsigned long to format
375 * @param shift the log2 of the base to format in (4 for hex, 3 for octal, 1 for binary)
376 * @param buf the character buffer to write to
377 * @param offset the offset in the destination buffer to start at
378 * @param len the number of characters to write
379 */
380 static void formatUnsignedLong(long val, int shift, char[] buf, int offset, int len) {
381 // assert shift > 0 && shift <=5 : "Illegal shift value";
382 // assert offset >= 0 && offset < buf.length : "illegal offset";
383 // assert len > 0 && (offset + len) <= buf.length : "illegal length";
384 int charPos = offset + len;
385 int radix = 1 << shift;
386 int mask = radix - 1;
387 do {
388 buf[--charPos] = Integer.digits[((int) val) & mask];
389 val >>>= shift;
390 } while (charPos > offset);
391 }
392
393 /**
394 * Returns a {@code String} object representing the specified
395 * {@code long}. The argument is converted to signed decimal
396 * representation and returned as a string, exactly as if the
397 * argument and the radix 10 were given as arguments to the {@link
398 * #toString(long, int)} method.
399 *
400 * @param i a {@code long} to be converted.
401 * @return a string representation of the argument in base 10.
402 */
403 public static String toString(long i) {
404 if (i == Long.MIN_VALUE)
405 return "-9223372036854775808";
406 int size = (i < 0) ? stringSize(-i) + 1 : stringSize(i);
407 char[] buf = new char[size];
408 getChars(i, size, buf);
409 return new String(buf, true);
410 }
411
412 /**
413 * Returns a string representation of the argument as an unsigned
414 * decimal value.
415 *
416 * The argument is converted to unsigned decimal representation
417 * and returned as a string exactly as if the argument and radix
418 * 10 were given as arguments to the {@link #toUnsignedString(long,
419 * int)} method.
420 *
421 * @param i an integer to be converted to an unsigned string.
422 * @return an unsigned string representation of the argument.
423 * @see #toUnsignedString(long, int)
424 * @since 1.8
425 */
426 public static String toUnsignedString(long i) {
427 return toUnsignedString(i, 10);
428 }
429
430 /**
431 * Places characters representing the integer i into the
432 * character array buf. The characters are placed into
433 * the buffer backwards starting with the least significant
434 * digit at the specified index (exclusive), and working
435 * backwards from there.
436 *
437 * Will fail if i == Long.MIN_VALUE
438 */
439 static void getChars(long i, int index, char[] buf) {
440 long q;
441 int r;
442 int charPos = index;
443 char sign = 0;
444
445 if (i < 0) {
446 sign = '-';
447 i = -i;
448 }
449
450 // Get 2 digits/iteration using longs until quotient fits into an int
451 while (i > Integer.MAX_VALUE) {
452 q = i / 100;
453 // really: r = i - (q * 100);
454 r = (int)(i - ((q << 6) + (q << 5) + (q << 2)));
455 i = q;
456 buf[--charPos] = Integer.DigitOnes[r];
457 buf[--charPos] = Integer.DigitTens[r];
458 }
459
460 // Get 2 digits/iteration using ints
461 int q2;
462 int i2 = (int)i;
463 while (i2 >= 65536) {
464 q2 = i2 / 100;
465 // really: r = i2 - (q * 100);
466 r = i2 - ((q2 << 6) + (q2 << 5) + (q2 << 2));
467 i2 = q2;
468 buf[--charPos] = Integer.DigitOnes[r];
469 buf[--charPos] = Integer.DigitTens[r];
470 }
471
472 // Fall thru to fast mode for smaller numbers
473 // assert(i2 <= 65536, i2);
474 for (;;) {
475 q2 = (i2 * 52429) >>> (16+3);
476 r = i2 - ((q2 << 3) + (q2 << 1)); // r = i2-(q2*10) ...
477 buf[--charPos] = Integer.digits[r];
478 i2 = q2;
479 if (i2 == 0) break;
480 }
481 if (sign != 0) {
482 buf[--charPos] = sign;
483 }
484 }
485
486 // Requires positive x
487 static int stringSize(long x) {
488 long p = 10;
489 for (int i=1; i<19; i++) {
490 if (x < p)
491 return i;
492 p = 10*p;
493 }
494 return 19;
495 }
496
497 /**
498 * Parses the string argument as a signed {@code long} in the
499 * radix specified by the second argument. The characters in the
500 * string must all be digits of the specified radix (as determined
501 * by whether {@link java.lang.Character#digit(char, int)} returns
502 * a nonnegative value), except that the first character may be an
503 * ASCII minus sign {@code '-'} ({@code '\u005Cu002D'}) to
504 * indicate a negative value or an ASCII plus sign {@code '+'}
505 * ({@code '\u005Cu002B'}) to indicate a positive value. The
506 * resulting {@code long} value is returned.
507 *
508 * <p>Note that neither the character {@code L}
509 * ({@code '\u005Cu004C'}) nor {@code l}
510 * ({@code '\u005Cu006C'}) is permitted to appear at the end
511 * of the string as a type indicator, as would be permitted in
512 * Java programming language source code - except that either
513 * {@code L} or {@code l} may appear as a digit for a
514 * radix greater than or equal to 22.
515 *
516 * <p>An exception of type {@code NumberFormatException} is
517 * thrown if any of the following situations occurs:
518 * <ul>
519 *
520 * <li>The first argument is {@code null} or is a string of
521 * length zero.
522 *
523 * <li>The {@code radix} is either smaller than {@link
524 * java.lang.Character#MIN_RADIX} or larger than {@link
525 * java.lang.Character#MAX_RADIX}.
526 *
527 * <li>Any character of the string is not a digit of the specified
528 * radix, except that the first character may be a minus sign
529 * {@code '-'} ({@code '\u005Cu002d'}) or plus sign {@code
530 * '+'} ({@code '\u005Cu002B'}) provided that the string is
531 * longer than length 1.
532 *
533 * <li>The value represented by the string is not a value of type
534 * {@code long}.
535 * </ul>
536 *
537 * <p>Examples:
538 * <blockquote><pre>
539 * parseLong("0", 10) returns 0L
540 * parseLong("473", 10) returns 473L
541 * parseLong("+42", 10) returns 42L
542 * parseLong("-0", 10) returns 0L
543 * parseLong("-FF", 16) returns -255L
544 * parseLong("1100110", 2) returns 102L
545 * parseLong("99", 8) throws a NumberFormatException
546 * parseLong("Hazelnut", 10) throws a NumberFormatException
547 * parseLong("Hazelnut", 36) returns 1356099454469L
548 * </pre></blockquote>
549 *
550 * @param s the {@code String} containing the
551 * {@code long} representation to be parsed.
552 * @param radix the radix to be used while parsing {@code s}.
553 * @return the {@code long} represented by the string argument in
554 * the specified radix.
555 * @throws NumberFormatException if the string does not contain a
556 * parsable {@code long}.
557 */
558 public static long parseLong(String s, int radix)
559 throws NumberFormatException
560 {
561 if (s == null) {
562 throw new NumberFormatException("null");
563 }
564
565 if (radix < Character.MIN_RADIX) {
566 throw new NumberFormatException("radix " + radix +
567 " less than Character.MIN_RADIX");
568 }
569 if (radix > Character.MAX_RADIX) {
570 throw new NumberFormatException("radix " + radix +
571 " greater than Character.MAX_RADIX");
572 }
573
574 boolean negative = false;
575 int i = 0, len = s.length();
576 long limit = -Long.MAX_VALUE;
577
578 if (len > 0) {
579 char firstChar = s.charAt(0);
580 if (firstChar < '0') { // Possible leading "+" or "-"
581 if (firstChar == '-') {
582 negative = true;
583 limit = Long.MIN_VALUE;
584 } else if (firstChar != '+') {
585 throw NumberFormatException.forInputString(s);
586 }
587
588 if (len == 1) { // Cannot have lone "+" or "-"
589 throw NumberFormatException.forInputString(s);
590 }
591 i++;
592 }
593 long multmin = limit / radix;
594 long result = 0;
595 while (i < len) {
596 // Accumulating negatively avoids surprises near MAX_VALUE
597 int digit = Character.digit(s.charAt(i++),radix);
598 if (digit < 0 || result < multmin) {
599 throw NumberFormatException.forInputString(s);
600 }
601 result *= radix;
602 if (result < limit + digit) {
603 throw NumberFormatException.forInputString(s);
604 }
605 result -= digit;
606 }
607 return negative ? result : -result;
608 } else {
609 throw NumberFormatException.forInputString(s);
610 }
611 }
612
613 /**
614 * Parses the {@link CharSequence} argument as a signed {@code long} in
615 * the specified {@code radix}, beginning at the specified
616 * {@code beginIndex} and extending to {@code endIndex - 1}.
617 *
618 * <p>The method does not take steps to guard against the
619 * {@code CharSequence} being mutated while parsing.
620 *
621 * @param s the {@code CharSequence} containing the {@code long}
622 * representation to be parsed
623 * @param beginIndex the beginning index, inclusive.
624 * @param endIndex the ending index, exclusive.
625 * @param radix the radix to be used while parsing {@code s}.
626 * @return the signed {@code long} represented by the subsequence in
627 * the specified radix.
628 * @throws NullPointerException if {@code s} is null.
629 * @throws IndexOutOfBoundsException if {@code beginIndex} is
630 * negative, or if {@code beginIndex} is greater than
631 * {@code endIndex} or if {@code endIndex} is greater than
632 * {@code s.length()}.
633 * @throws NumberFormatException if the {@code CharSequence} does not
634 * contain a parsable {@code int} in the specified
635 * {@code radix}, or if {@code radix} is either smaller than
636 * {@link java.lang.Character#MIN_RADIX} or larger than
637 * {@link java.lang.Character#MAX_RADIX}.
638 * @since 1.9
639 */
640 public static long parseLong(CharSequence s, int beginIndex, int endIndex, int radix)
641 throws NumberFormatException {
642 s = Objects.requireNonNull(s);
643
644 if (beginIndex < 0 || beginIndex > endIndex || endIndex > s.length()) {
645 throw new IndexOutOfBoundsException();
646 }
647 if (radix < Character.MIN_RADIX) {
648 throw new NumberFormatException("radix " + radix +
649 " less than Character.MIN_RADIX");
650 }
651 if (radix > Character.MAX_RADIX) {
652 throw new NumberFormatException("radix " + radix +
653 " greater than Character.MAX_RADIX");
654 }
655
656 boolean negative = false;
657 int i = beginIndex;
658 long limit = -Long.MAX_VALUE;
659
660 if (i < endIndex) {
661 char firstChar = s.charAt(i);
662 if (firstChar < '0') { // Possible leading "+" or "-"
663 if (firstChar == '-') {
664 negative = true;
665 limit = Long.MIN_VALUE;
666 } else if (firstChar != '+') {
667 throw NumberFormatException.forCharSequence(s, beginIndex,
668 endIndex, i);
669 }
670 i++;
671 }
672 if (i >= endIndex) { // Cannot have lone "+", "-" or ""
673 throw NumberFormatException.forCharSequence(s, beginIndex,
674 endIndex, i);
675 }
676 long multmin = limit / radix;
677 long result = 0;
678 while (i < endIndex) {
679 // Accumulating negatively avoids surprises near MAX_VALUE
680 int digit = Character.digit(s.charAt(i), radix);
681 if (digit < 0 || result < multmin) {
682 throw NumberFormatException.forCharSequence(s, beginIndex,
683 endIndex, i);
684 }
685 result *= radix;
686 if (result < limit + digit) {
687 throw NumberFormatException.forCharSequence(s, beginIndex,
688 endIndex, i);
689 }
690 i++;
691 result -= digit;
692 }
693 return negative ? result : -result;
694 } else {
695 throw new NumberFormatException("");
696 }
697 }
698
699 /**
700 * Parses the string argument as a signed decimal {@code long}.
701 * The characters in the string must all be decimal digits, except
702 * that the first character may be an ASCII minus sign {@code '-'}
703 * ({@code \u005Cu002D'}) to indicate a negative value or an
704 * ASCII plus sign {@code '+'} ({@code '\u005Cu002B'}) to
705 * indicate a positive value. The resulting {@code long} value is
706 * returned, exactly as if the argument and the radix {@code 10}
707 * were given as arguments to the {@link
708 * #parseLong(java.lang.String, int)} method.
709 *
710 * <p>Note that neither the character {@code L}
711 * ({@code '\u005Cu004C'}) nor {@code l}
712 * ({@code '\u005Cu006C'}) is permitted to appear at the end
713 * of the string as a type indicator, as would be permitted in
714 * Java programming language source code.
715 *
716 * @param s a {@code String} containing the {@code long}
717 * representation to be parsed
718 * @return the {@code long} represented by the argument in
719 * decimal.
720 * @throws NumberFormatException if the string does not contain a
721 * parsable {@code long}.
722 */
723 public static long parseLong(String s) throws NumberFormatException {
724 return parseLong(s, 10);
725 }
726
727 /**
728 * Parses the string argument as an unsigned {@code long} in the
729 * radix specified by the second argument. An unsigned integer
730 * maps the values usually associated with negative numbers to
731 * positive numbers larger than {@code MAX_VALUE}.
732 *
733 * The characters in the string must all be digits of the
734 * specified radix (as determined by whether {@link
735 * java.lang.Character#digit(char, int)} returns a nonnegative
736 * value), except that the first character may be an ASCII plus
737 * sign {@code '+'} ({@code '\u005Cu002B'}). The resulting
738 * integer value is returned.
739 *
740 * <p>An exception of type {@code NumberFormatException} is
741 * thrown if any of the following situations occurs:
742 * <ul>
743 * <li>The first argument is {@code null} or is a string of
744 * length zero.
745 *
746 * <li>The radix is either smaller than
747 * {@link java.lang.Character#MIN_RADIX} or
748 * larger than {@link java.lang.Character#MAX_RADIX}.
749 *
750 * <li>Any character of the string is not a digit of the specified
751 * radix, except that the first character may be a plus sign
752 * {@code '+'} ({@code '\u005Cu002B'}) provided that the
753 * string is longer than length 1.
754 *
755 * <li>The value represented by the string is larger than the
756 * largest unsigned {@code long}, 2<sup>64</sup>-1.
757 *
758 * </ul>
759 *
760 *
761 * @param s the {@code String} containing the unsigned integer
762 * representation to be parsed
763 * @param radix the radix to be used while parsing {@code s}.
764 * @return the unsigned {@code long} represented by the string
765 * argument in the specified radix.
766 * @throws NumberFormatException if the {@code String}
767 * does not contain a parsable {@code long}.
768 * @since 1.8
769 */
770 public static long parseUnsignedLong(String s, int radix)
771 throws NumberFormatException {
772 if (s == null) {
773 throw new NumberFormatException("null");
774 }
775
776 int len = s.length();
777 if (len > 0) {
778 char firstChar = s.charAt(0);
779 if (firstChar == '-') {
780 throw new
781 NumberFormatException(String.format("Illegal leading minus sign " +
782 "on unsigned string %s.", s));
783 } else {
784 if (len <= 12 || // Long.MAX_VALUE in Character.MAX_RADIX is 13 digits
785 (radix == 10 && len <= 18) ) { // Long.MAX_VALUE in base 10 is 19 digits
786 return parseLong(s, radix);
787 }
788
789 // No need for range checks on len due to testing above.
790 long first = parseLong(s, 0, len - 1, radix);
791 int second = Character.digit(s.charAt(len - 1), radix);
792 if (second < 0) {
793 throw new NumberFormatException("Bad digit at end of " + s);
794 }
795 long result = first * radix + second;
796
797 /*
798 * Test leftmost bits of multiprecision extension of first*radix
799 * for overflow. The number of bits needed is defined by
800 * GUARD_BIT = ceil(log2(Character.MAX_RADIX)) + 1 = 7. Then
801 * int guard = radix*(int)(first >>> (64 - GUARD_BIT)) and
802 * overflow is tested by splitting guard in the ranges
803 * guard < 92, 92 <= guard < 128, and 128 <= guard, where
804 * 92 = 128 - Character.MAX_RADIX. Note that guard cannot take
805 * on a value which does not include a prime factor in the legal
806 * radix range.
807 */
808 int guard = radix * (int) (first >>> 57);
809 if (guard >= 128 ||
810 (result >= 0 && guard >= 128 - Character.MAX_RADIX)) {
811 /*
812 * For purposes of exposition, the programmatic statements
813 * below should be taken to be multi-precision, i.e., not
814 * subject to overflow.
815 *
816 * A) Condition guard >= 128:
817 * If guard >= 128 then first*radix >= 2^7 * 2^57 = 2^64
818 * hence always overflow.
819 *
820 * B) Condition guard < 92:
821 * Define left7 = first >>> 57.
822 * Given first = (left7 * 2^57) + (first & (2^57 - 1)) then
823 * result <= (radix*left7)*2^57 + radix*(2^57 - 1) + second.
824 * Thus if radix*left7 < 92, radix <= 36, and second < 36,
825 * then result < 92*2^57 + 36*(2^57 - 1) + 36 = 2^64 hence
826 * never overflow.
827 *
828 * C) Condition 92 <= guard < 128:
829 * first*radix + second >= radix*left7*2^57 + second
830 * so that first*radix + second >= 92*2^57 + 0 > 2^63
831 *
832 * D) Condition guard < 128:
833 * radix*first <= (radix*left7) * 2^57 + radix*(2^57 - 1)
834 * so
835 * radix*first + second <= (radix*left7) * 2^57 + radix*(2^57 - 1) + 36
836 * thus
837 * radix*first + second < 128 * 2^57 + 36*2^57 - radix + 36
838 * whence
839 * radix*first + second < 2^64 + 2^6*2^57 = 2^64 + 2^63
840 *
841 * E) Conditions C, D, and result >= 0:
842 * C and D combined imply the mathematical result
843 * 2^63 < first*radix + second < 2^64 + 2^63. The lower
844 * bound is therefore negative as a signed long, but the
845 * upper bound is too small to overflow again after the
846 * signed long overflows to positive above 2^64 - 1. Hence
847 * result >= 0 implies overflow given C and D.
848 */
849 throw new NumberFormatException(String.format("String value %s exceeds " +
850 "range of unsigned long.", s));
851 }
852 return result;
853 }
854 } else {
855 throw NumberFormatException.forInputString(s);
856 }
857 }
858
859 /**
860 * Parses the {@link CharSequence} argument as an unsigned {@code long} in
861 * the specified {@code radix}, beginning at the specified
862 * {@code beginIndex} and extending to {@code endIndex - 1}.
863 *
864 * <p>The method does not take steps to guard against the
865 * {@code CharSequence} being mutated while parsing.
866 *
867 * @param s the {@code CharSequence} containing the unsigned
868 * {@code long} representation to be parsed
869 * @param beginIndex the beginning index, inclusive.
870 * @param endIndex the ending index, exclusive.
871 * @param radix the radix to be used while parsing {@code s}.
872 * @return the unsigned {@code long} represented by the subsequence in
873 * the specified radix.
874 * @throws NullPointerException if {@code s} is null.
875 * @throws IndexOutOfBoundsException if {@code beginIndex} is
876 * negative, or if {@code beginIndex} is greater than
877 * {@code endIndex} or if {@code endIndex} is greater than
878 * {@code s.length()}.
879 * @throws NumberFormatException if the {@code CharSequence} does not
880 * contain a parsable unsigned {@code long} in the specified
881 * {@code radix}, or if {@code radix} is either smaller than
882 * {@link java.lang.Character#MIN_RADIX} or larger than
883 * {@link java.lang.Character#MAX_RADIX}.
884 * @since 1.9
885 */
886 public static long parseUnsignedLong(CharSequence s, int beginIndex, int endIndex, int radix)
887 throws NumberFormatException {
888 s = Objects.requireNonNull(s);
889
890 if (beginIndex < 0 || beginIndex > endIndex || endIndex > s.length()) {
891 throw new IndexOutOfBoundsException();
892 }
893 int start = beginIndex, len = endIndex - beginIndex;
894
895 if (len > 0) {
896 char firstChar = s.charAt(start);
897 if (firstChar == '-') {
898 throw new NumberFormatException(String.format("Illegal leading minus sign " +
899 "on unsigned string %s.", s.subSequence(start, start + len)));
900 } else {
901 if (len <= 12 || // Long.MAX_VALUE in Character.MAX_RADIX is 13 digits
902 (radix == 10 && len <= 18) ) { // Long.MAX_VALUE in base 10 is 19 digits
903 return parseLong(s, start, start + len, radix);
904 }
905
906 // No need for range checks on end due to testing above.
907 long first = parseLong(s, start, start + len - 1, radix);
908 int second = Character.digit(s.charAt(start + len - 1), radix);
909 if (second < 0) {
910 throw new NumberFormatException("Bad digit at end of " +
911 s.subSequence(start, start + len));
912 }
913 long result = first * radix + second;
914
915 /*
916 * Test leftmost bits of multiprecision extension of first*radix
917 * for overflow. The number of bits needed is defined by
918 * GUARD_BIT = ceil(log2(Character.MAX_RADIX)) + 1 = 7. Then
919 * int guard = radix*(int)(first >>> (64 - GUARD_BIT)) and
920 * overflow is tested by splitting guard in the ranges
921 * guard < 92, 92 <= guard < 128, and 128 <= guard, where
922 * 92 = 128 - Character.MAX_RADIX. Note that guard cannot take
923 * on a value which does not include a prime factor in the legal
924 * radix range.
925 */
926 int guard = radix * (int) (first >>> 57);
927 if (guard >= 128 ||
928 (result >= 0 && guard >= 128 - Character.MAX_RADIX)) {
929 /*
930 * For purposes of exposition, the programmatic statements
931 * below should be taken to be multi-precision, i.e., not
932 * subject to overflow.
933 *
934 * A) Condition guard >= 128:
935 * If guard >= 128 then first*radix >= 2^7 * 2^57 = 2^64
936 * hence always overflow.
937 *
938 * B) Condition guard < 92:
939 * Define left7 = first >>> 57.
940 * Given first = (left7 * 2^57) + (first & (2^57 - 1)) then
941 * result <= (radix*left7)*2^57 + radix*(2^57 - 1) + second.
942 * Thus if radix*left7 < 92, radix <= 36, and second < 36,
943 * then result < 92*2^57 + 36*(2^57 - 1) + 36 = 2^64 hence
944 * never overflow.
945 *
946 * C) Condition 92 <= guard < 128:
947 * first*radix + second >= radix*left7*2^57 + second
948 * so that first*radix + second >= 92*2^57 + 0 > 2^63
949 *
950 * D) Condition guard < 128:
951 * radix*first <= (radix*left7) * 2^57 + radix*(2^57 - 1)
952 * so
953 * radix*first + second <= (radix*left7) * 2^57 + radix*(2^57 - 1) + 36
954 * thus
955 * radix*first + second < 128 * 2^57 + 36*2^57 - radix + 36
956 * whence
957 * radix*first + second < 2^64 + 2^6*2^57 = 2^64 + 2^63
958 *
959 * E) Conditions C, D, and result >= 0:
960 * C and D combined imply the mathematical result
961 * 2^63 < first*radix + second < 2^64 + 2^63. The lower
962 * bound is therefore negative as a signed long, but the
963 * upper bound is too small to overflow again after the
964 * signed long overflows to positive above 2^64 - 1. Hence
965 * result >= 0 implies overflow given C and D.
966 */
967 throw new NumberFormatException(String.format("String value %s exceeds " +
968 "range of unsigned long.", s.subSequence(start, start + len)));
969 }
970 return result;
971 }
972 } else {
973 throw NumberFormatException.forInputString("");
974 }
975 }
976
977 /**
978 * Parses the string argument as an unsigned decimal {@code long}. The
979 * characters in the string must all be decimal digits, except
980 * that the first character may be an ASCII plus sign {@code
981 * '+'} ({@code '\u005Cu002B'}). The resulting integer value
982 * is returned, exactly as if the argument and the radix 10 were
983 * given as arguments to the {@link
984 * #parseUnsignedLong(java.lang.String, int)} method.
985 *
986 * @param s a {@code String} containing the unsigned {@code long}
987 * representation to be parsed
988 * @return the unsigned {@code long} value represented by the decimal string argument
989 * @throws NumberFormatException if the string does not contain a
990 * parsable unsigned integer.
991 * @since 1.8
992 */
993 public static long parseUnsignedLong(String s) throws NumberFormatException {
994 return parseUnsignedLong(s, 10);
995 }
996
997 /**
998 * Returns a {@code Long} object holding the value
999 * extracted from the specified {@code String} when parsed
1000 * with the radix given by the second argument. The first
1001 * argument is interpreted as representing a signed
1002 * {@code long} in the radix specified by the second
1003 * argument, exactly as if the arguments were given to the {@link
1004 * #parseLong(java.lang.String, int)} method. The result is a
1005 * {@code Long} object that represents the {@code long}
1006 * value specified by the string.
1007 *
1008 * <p>In other words, this method returns a {@code Long} object equal
1009 * to the value of:
1010 *
1011 * <blockquote>
1012 * {@code new Long(Long.parseLong(s, radix))}
1013 * </blockquote>
1014 *
1015 * @param s the string to be parsed
1016 * @param radix the radix to be used in interpreting {@code s}
1017 * @return a {@code Long} object holding the value
1018 * represented by the string argument in the specified
1019 * radix.
1020 * @throws NumberFormatException If the {@code String} does not
1021 * contain a parsable {@code long}.
1022 */
1023 public static Long valueOf(String s, int radix) throws NumberFormatException {
1024 return Long.valueOf(parseLong(s, radix));
1025 }
1026
1027 /**
1028 * Returns a {@code Long} object holding the value
1029 * of the specified {@code String}. The argument is
1030 * interpreted as representing a signed decimal {@code long},
1031 * exactly as if the argument were given to the {@link
1032 * #parseLong(java.lang.String)} method. The result is a
1033 * {@code Long} object that represents the integer value
1034 * specified by the string.
1035 *
1036 * <p>In other words, this method returns a {@code Long} object
1037 * equal to the value of:
1038 *
1039 * <blockquote>
1040 * {@code new Long(Long.parseLong(s))}
1041 * </blockquote>
1042 *
1043 * @param s the string to be parsed.
1044 * @return a {@code Long} object holding the value
1045 * represented by the string argument.
1046 * @throws NumberFormatException If the string cannot be parsed
1047 * as a {@code long}.
1048 */
1049 public static Long valueOf(String s) throws NumberFormatException
1050 {
1051 return Long.valueOf(parseLong(s, 10));
1052 }
1053
1054 private static class LongCache {
1055 private LongCache(){}
1056
1057 static final Long cache[] = new Long[-(-128) + 127 + 1];
1058
1059 static {
1060 for(int i = 0; i < cache.length; i++) {
1061 int val = i - 128;
1062 cache[i] = (val == 0) ? ZERO : new Long(val);
1063 }
1064 }
1065 }
1066
1067 /**
1068 * Returns a {@code Long} instance representing the specified
1069 * {@code long} value.
1070 * If a new {@code Long} instance is not required, this method
1071 * should generally be used in preference to the constructor
1072 * {@link #Long(long)}, as this method is likely to yield
1073 * significantly better space and time performance by caching
1074 * frequently requested values.
1075 *
1076 * Note that unlike the {@linkplain Integer#valueOf(int)
1077 * corresponding method} in the {@code Integer} class, this method
1078 * is <em>not</em> required to cache values within a particular
1079 * range.
1080 *
1081 * @param l a long value.
1082 * @return a {@code Long} instance representing {@code l}.
1083 * @since 1.5
1084 */
1085 @HotSpotIntrinsicCandidate
1086 public static Long valueOf(long l) {
1087 final int offset = 128;
1088 if (l >= -128 && l <= 127) { // will cache
1089 return LongCache.cache[(int)l + offset];
1090 }
1091 return new Long(l);
1092 }
1093
1094 /**
1095 * Decodes a {@code String} into a {@code Long}.
1096 * Accepts decimal, hexadecimal, and octal numbers given by the
1097 * following grammar:
1098 *
1099 * <blockquote>
1100 * <dl>
1101 * <dt><i>DecodableString:</i>
1102 * <dd><i>Sign<sub>opt</sub> DecimalNumeral</i>
1103 * <dd><i>Sign<sub>opt</sub></i> {@code 0x} <i>HexDigits</i>
1104 * <dd><i>Sign<sub>opt</sub></i> {@code 0X} <i>HexDigits</i>
1105 * <dd><i>Sign<sub>opt</sub></i> {@code #} <i>HexDigits</i>
1106 * <dd><i>Sign<sub>opt</sub></i> {@code 0} <i>OctalDigits</i>
1107 *
1108 * <dt><i>Sign:</i>
1109 * <dd>{@code -}
1110 * <dd>{@code +}
1111 * </dl>
1112 * </blockquote>
1113 *
1114 * <i>DecimalNumeral</i>, <i>HexDigits</i>, and <i>OctalDigits</i>
1115 * are as defined in section 3.10.1 of
1116 * <cite>The Java™ Language Specification</cite>,
1117 * except that underscores are not accepted between digits.
1118 *
1119 * <p>The sequence of characters following an optional
1120 * sign and/or radix specifier ("{@code 0x}", "{@code 0X}",
1121 * "{@code #}", or leading zero) is parsed as by the {@code
1122 * Long.parseLong} method with the indicated radix (10, 16, or 8).
1123 * This sequence of characters must represent a positive value or
1124 * a {@link NumberFormatException} will be thrown. The result is
1125 * negated if first character of the specified {@code String} is
1126 * the minus sign. No whitespace characters are permitted in the
1127 * {@code String}.
1128 *
1129 * @param nm the {@code String} to decode.
1130 * @return a {@code Long} object holding the {@code long}
1131 * value represented by {@code nm}
1132 * @throws NumberFormatException if the {@code String} does not
1133 * contain a parsable {@code long}.
1134 * @see java.lang.Long#parseLong(String, int)
1135 * @since 1.2
1136 */
1137 public static Long decode(String nm) throws NumberFormatException {
1138 int radix = 10;
1139 int index = 0;
1140 boolean negative = false;
1141 Long result;
1142
1143 if (nm.length() == 0)
1144 throw new NumberFormatException("Zero length string");
1145 char firstChar = nm.charAt(0);
1146 // Handle sign, if present
1147 if (firstChar == '-') {
1148 negative = true;
1149 index++;
1150 } else if (firstChar == '+')
1151 index++;
1152
1153 // Handle radix specifier, if present
1154 if (nm.startsWith("0x", index) || nm.startsWith("0X", index)) {
1155 index += 2;
1156 radix = 16;
1157 }
1158 else if (nm.startsWith("#", index)) {
1159 index ++;
1160 radix = 16;
1161 }
1162 else if (nm.startsWith("0", index) && nm.length() > 1 + index) {
1163 index ++;
1164 radix = 8;
1165 }
1166
1167 if (nm.startsWith("-", index) || nm.startsWith("+", index))
1168 throw new NumberFormatException("Sign character in wrong position");
1169
1170 try {
1171 result = Long.valueOf(nm.substring(index), radix);
1172 result = negative ? Long.valueOf(-result.longValue()) : result;
1173 } catch (NumberFormatException e) {
1174 // If number is Long.MIN_VALUE, we'll end up here. The next line
1175 // handles this case, and causes any genuine format error to be
1176 // rethrown.
1177 String constant = negative ? ("-" + nm.substring(index))
1178 : nm.substring(index);
1179 result = Long.valueOf(constant, radix);
1180 }
1181 return result;
1182 }
1183
1184 /**
1185 * The value of the {@code Long}.
1186 *
1187 * @serial
1188 */
1189 private final long value;
1190
1191 /**
1192 * Constructs a newly allocated {@code Long} object that
1193 * represents the specified {@code long} argument.
1194 *
1195 * @param value the value to be represented by the
1196 * {@code Long} object.
1197 */
1198 public Long(long value) {
1199 this.value = value;
1200 }
1201
1202 /**
1203 * Constructs a newly allocated {@code Long} object that
1204 * represents the {@code long} value indicated by the
1205 * {@code String} parameter. The string is converted to a
1206 * {@code long} value in exactly the manner used by the
1207 * {@code parseLong} method for radix 10.
1208 *
1209 * @param s the {@code String} to be converted to a
1210 * {@code Long}.
1211 * @throws NumberFormatException if the {@code String} does not
1212 * contain a parsable {@code long}.
1213 * @see java.lang.Long#parseLong(java.lang.String, int)
1214 */
1215 public Long(String s) throws NumberFormatException {
1216 this.value = parseLong(s, 10);
1217 }
1218
1219 /**
1220 * Returns the value of this {@code Long} as a {@code byte} after
1221 * a narrowing primitive conversion.
1222 * @jls 5.1.3 Narrowing Primitive Conversions
1223 */
1224 public byte byteValue() {
1225 return (byte)value;
1226 }
1227
1228 /**
1229 * Returns the value of this {@code Long} as a {@code short} after
1230 * a narrowing primitive conversion.
1231 * @jls 5.1.3 Narrowing Primitive Conversions
1232 */
1233 public short shortValue() {
1234 return (short)value;
1235 }
1236
1237 /**
1238 * Returns the value of this {@code Long} as an {@code int} after
1239 * a narrowing primitive conversion.
1240 * @jls 5.1.3 Narrowing Primitive Conversions
1241 */
1242 public int intValue() {
1243 return (int)value;
1244 }
1245
1246 /**
1247 * Returns the value of this {@code Long} as a
1248 * {@code long} value.
1249 */
1250 @HotSpotIntrinsicCandidate
1251 public long longValue() {
1252 return value;
1253 }
1254
1255 /**
1256 * Returns the value of this {@code Long} as a {@code float} after
1257 * a widening primitive conversion.
1258 * @jls 5.1.2 Widening Primitive Conversions
1259 */
1260 public float floatValue() {
1261 return (float)value;
1262 }
1263
1264 /**
1265 * Returns the value of this {@code Long} as a {@code double}
1266 * after a widening primitive conversion.
1267 * @jls 5.1.2 Widening Primitive Conversions
1268 */
1269 public double doubleValue() {
1270 return (double)value;
1271 }
1272
1273 /**
1274 * Returns a {@code String} object representing this
1275 * {@code Long}'s value. The value is converted to signed
1276 * decimal representation and returned as a string, exactly as if
1277 * the {@code long} value were given as an argument to the
1278 * {@link java.lang.Long#toString(long)} method.
1279 *
1280 * @return a string representation of the value of this object in
1281 * base 10.
1282 */
1283 public String toString() {
1284 return toString(value);
1285 }
1286
1287 /**
1288 * Returns a hash code for this {@code Long}. The result is
1289 * the exclusive OR of the two halves of the primitive
1290 * {@code long} value held by this {@code Long}
1291 * object. That is, the hashcode is the value of the expression:
1292 *
1293 * <blockquote>
1294 * {@code (int)(this.longValue()^(this.longValue()>>>32))}
1295 * </blockquote>
1296 *
1297 * @return a hash code value for this object.
1298 */
1299 @Override
1300 public int hashCode() {
1301 return Long.hashCode(value);
1302 }
1303
1304 /**
1305 * Returns a hash code for a {@code long} value; compatible with
1306 * {@code Long.hashCode()}.
1307 *
1308 * @param value the value to hash
1309 * @return a hash code value for a {@code long} value.
1310 * @since 1.8
1311 */
1312 public static int hashCode(long value) {
1313 return (int)(value ^ (value >>> 32));
1314 }
1315
1316 /**
1317 * Compares this object to the specified object. The result is
1318 * {@code true} if and only if the argument is not
1319 * {@code null} and is a {@code Long} object that
1320 * contains the same {@code long} value as this object.
1321 *
1322 * @param obj the object to compare with.
1323 * @return {@code true} if the objects are the same;
1324 * {@code false} otherwise.
1325 */
1326 public boolean equals(Object obj) {
1327 if (obj instanceof Long) {
1328 return value == ((Long)obj).longValue();
1329 }
1330 return false;
1331 }
1332
1333 /**
1334 * Determines the {@code long} value of the system property
1335 * with the specified name.
1336 *
1337 * <p>The first argument is treated as the name of a system
1338 * property. System properties are accessible through the {@link
1339 * java.lang.System#getProperty(java.lang.String)} method. The
1340 * string value of this property is then interpreted as a {@code
1341 * long} value using the grammar supported by {@link Long#decode decode}
1342 * and a {@code Long} object representing this value is returned.
1343 *
1344 * <p>If there is no property with the specified name, if the
1345 * specified name is empty or {@code null}, or if the property
1346 * does not have the correct numeric format, then {@code null} is
1347 * returned.
1348 *
1349 * <p>In other words, this method returns a {@code Long} object
1350 * equal to the value of:
1351 *
1352 * <blockquote>
1353 * {@code getLong(nm, null)}
1354 * </blockquote>
1355 *
1356 * @param nm property name.
1357 * @return the {@code Long} value of the property.
1358 * @throws SecurityException for the same reasons as
1359 * {@link System#getProperty(String) System.getProperty}
1360 * @see java.lang.System#getProperty(java.lang.String)
1361 * @see java.lang.System#getProperty(java.lang.String, java.lang.String)
1362 */
1363 public static Long getLong(String nm) {
1364 return getLong(nm, null);
1365 }
1366
1367 /**
1368 * Determines the {@code long} value of the system property
1369 * with the specified name.
1370 *
1371 * <p>The first argument is treated as the name of a system
1372 * property. System properties are accessible through the {@link
1373 * java.lang.System#getProperty(java.lang.String)} method. The
1374 * string value of this property is then interpreted as a {@code
1375 * long} value using the grammar supported by {@link Long#decode decode}
1376 * and a {@code Long} object representing this value is returned.
1377 *
1378 * <p>The second argument is the default value. A {@code Long} object
1379 * that represents the value of the second argument is returned if there
1380 * is no property of the specified name, if the property does not have
1381 * the correct numeric format, or if the specified name is empty or null.
1382 *
1383 * <p>In other words, this method returns a {@code Long} object equal
1384 * to the value of:
1385 *
1386 * <blockquote>
1387 * {@code getLong(nm, new Long(val))}
1388 * </blockquote>
1389 *
1390 * but in practice it may be implemented in a manner such as:
1391 *
1392 * <blockquote><pre>
1393 * Long result = getLong(nm, null);
1394 * return (result == null) ? new Long(val) : result;
1395 * </pre></blockquote>
1396 *
1397 * to avoid the unnecessary allocation of a {@code Long} object when
1398 * the default value is not needed.
1399 *
1400 * @param nm property name.
1401 * @param val default value.
1402 * @return the {@code Long} value of the property.
1403 * @throws SecurityException for the same reasons as
1404 * {@link System#getProperty(String) System.getProperty}
1405 * @see java.lang.System#getProperty(java.lang.String)
1406 * @see java.lang.System#getProperty(java.lang.String, java.lang.String)
1407 */
1408 public static Long getLong(String nm, long val) {
1409 Long result = Long.getLong(nm, null);
1410 return (result == null) ? Long.valueOf(val) : result;
1411 }
1412
1413 /**
1414 * Returns the {@code long} value of the system property with
1415 * the specified name. The first argument is treated as the name
1416 * of a system property. System properties are accessible through
1417 * the {@link java.lang.System#getProperty(java.lang.String)}
1418 * method. The string value of this property is then interpreted
1419 * as a {@code long} value, as per the
1420 * {@link Long#decode decode} method, and a {@code Long} object
1421 * representing this value is returned; in summary:
1422 *
1423 * <ul>
1424 * <li>If the property value begins with the two ASCII characters
1425 * {@code 0x} or the ASCII character {@code #}, not followed by
1426 * a minus sign, then the rest of it is parsed as a hexadecimal integer
1427 * exactly as for the method {@link #valueOf(java.lang.String, int)}
1428 * with radix 16.
1429 * <li>If the property value begins with the ASCII character
1430 * {@code 0} followed by another character, it is parsed as
1431 * an octal integer exactly as by the method {@link
1432 * #valueOf(java.lang.String, int)} with radix 8.
1433 * <li>Otherwise the property value is parsed as a decimal
1434 * integer exactly as by the method
1435 * {@link #valueOf(java.lang.String, int)} with radix 10.
1436 * </ul>
1437 *
1438 * <p>Note that, in every case, neither {@code L}
1439 * ({@code '\u005Cu004C'}) nor {@code l}
1440 * ({@code '\u005Cu006C'}) is permitted to appear at the end
1441 * of the property value as a type indicator, as would be
1442 * permitted in Java programming language source code.
1443 *
1444 * <p>The second argument is the default value. The default value is
1445 * returned if there is no property of the specified name, if the
1446 * property does not have the correct numeric format, or if the
1447 * specified name is empty or {@code null}.
1448 *
1449 * @param nm property name.
1450 * @param val default value.
1451 * @return the {@code Long} value of the property.
1452 * @throws SecurityException for the same reasons as
1453 * {@link System#getProperty(String) System.getProperty}
1454 * @see System#getProperty(java.lang.String)
1455 * @see System#getProperty(java.lang.String, java.lang.String)
1456 */
1457 public static Long getLong(String nm, Long val) {
1458 String v = null;
1459 try {
1460 v = System.getProperty(nm);
1461 } catch (IllegalArgumentException | NullPointerException e) {
1462 }
1463 if (v != null) {
1464 try {
1465 return Long.decode(v);
1466 } catch (NumberFormatException e) {
1467 }
1468 }
1469 return val;
1470 }
1471
1472 /**
1473 * Compares two {@code Long} objects numerically.
1474 *
1475 * @param anotherLong the {@code Long} to be compared.
1476 * @return the value {@code 0} if this {@code Long} is
1477 * equal to the argument {@code Long}; a value less than
1478 * {@code 0} if this {@code Long} is numerically less
1479 * than the argument {@code Long}; and a value greater
1480 * than {@code 0} if this {@code Long} is numerically
1481 * greater than the argument {@code Long} (signed
1482 * comparison).
1483 * @since 1.2
1484 */
1485 public int compareTo(Long anotherLong) {
1486 return compare(this.value, anotherLong.value);
1487 }
1488
1489 /**
1490 * Compares two {@code long} values numerically.
1491 * The value returned is identical to what would be returned by:
1492 * <pre>
1493 * Long.valueOf(x).compareTo(Long.valueOf(y))
1494 * </pre>
1495 *
1496 * @param x the first {@code long} to compare
1497 * @param y the second {@code long} to compare
1498 * @return the value {@code 0} if {@code x == y};
1499 * a value less than {@code 0} if {@code x < y}; and
1500 * a value greater than {@code 0} if {@code x > y}
1501 * @since 1.7
1502 */
1503 public static int compare(long x, long y) {
1504 return (x < y) ? -1 : ((x == y) ? 0 : 1);
1505 }
1506
1507 /**
1508 * Compares two {@code long} values numerically treating the values
1509 * as unsigned.
1510 *
1511 * @param x the first {@code long} to compare
1512 * @param y the second {@code long} to compare
1513 * @return the value {@code 0} if {@code x == y}; a value less
1514 * than {@code 0} if {@code x < y} as unsigned values; and
1515 * a value greater than {@code 0} if {@code x > y} as
1516 * unsigned values
1517 * @since 1.8
1518 */
1519 public static int compareUnsigned(long x, long y) {
1520 return compare(x + MIN_VALUE, y + MIN_VALUE);
1521 }
1522
1523
1524 /**
1525 * Returns the unsigned quotient of dividing the first argument by
1526 * the second where each argument and the result is interpreted as
1527 * an unsigned value.
1528 *
1529 * <p>Note that in two's complement arithmetic, the three other
1530 * basic arithmetic operations of add, subtract, and multiply are
1531 * bit-wise identical if the two operands are regarded as both
1532 * being signed or both being unsigned. Therefore separate {@code
1533 * addUnsigned}, etc. methods are not provided.
1534 *
1535 * @param dividend the value to be divided
1536 * @param divisor the value doing the dividing
1537 * @return the unsigned quotient of the first argument divided by
1538 * the second argument
1539 * @see #remainderUnsigned
1540 * @since 1.8
1541 */
1542 public static long divideUnsigned(long dividend, long divisor) {
1543 if (divisor < 0L) { // signed comparison
1544 // Answer must be 0 or 1 depending on relative magnitude
1545 // of dividend and divisor.
1546 return (compareUnsigned(dividend, divisor)) < 0 ? 0L :1L;
1547 }
1548
1549 if (dividend > 0) // Both inputs non-negative
1550 return dividend/divisor;
1551 else {
1552 /*
1553 * For simple code, leveraging BigInteger. Longer and faster
1554 * code written directly in terms of operations on longs is
1555 * possible; see "Hacker's Delight" for divide and remainder
1556 * algorithms.
1557 */
1558 return toUnsignedBigInteger(dividend).
1559 divide(toUnsignedBigInteger(divisor)).longValue();
1560 }
1561 }
1562
1563 /**
1564 * Returns the unsigned remainder from dividing the first argument
1565 * by the second where each argument and the result is interpreted
1566 * as an unsigned value.
1567 *
1568 * @param dividend the value to be divided
1569 * @param divisor the value doing the dividing
1570 * @return the unsigned remainder of the first argument divided by
1571 * the second argument
1572 * @see #divideUnsigned
1573 * @since 1.8
1574 */
1575 public static long remainderUnsigned(long dividend, long divisor) {
1576 if (dividend > 0 && divisor > 0) { // signed comparisons
1577 return dividend % divisor;
1578 } else {
1579 if (compareUnsigned(dividend, divisor) < 0) // Avoid explicit check for 0 divisor
1580 return dividend;
1581 else
1582 return toUnsignedBigInteger(dividend).
1583 remainder(toUnsignedBigInteger(divisor)).longValue();
1584 }
1585 }
1586
1587 // Bit Twiddling
1588
1589 /**
1590 * The number of bits used to represent a {@code long} value in two's
1591 * complement binary form.
1592 *
1593 * @since 1.5
1594 */
1595 @Native public static final int SIZE = 64;
1596
1597 /**
1598 * The number of bytes used to represent a {@code long} value in two's
1599 * complement binary form.
1600 *
1601 * @since 1.8
1602 */
1603 public static final int BYTES = SIZE / Byte.SIZE;
1604
1605 /**
1606 * Returns a {@code long} value with at most a single one-bit, in the
1607 * position of the highest-order ("leftmost") one-bit in the specified
1608 * {@code long} value. Returns zero if the specified value has no
1609 * one-bits in its two's complement binary representation, that is, if it
1610 * is equal to zero.
1611 *
1612 * @param i the value whose highest one bit is to be computed
1613 * @return a {@code long} value with a single one-bit, in the position
1614 * of the highest-order one-bit in the specified value, or zero if
1615 * the specified value is itself equal to zero.
1616 * @since 1.5
1617 */
1618 public static long highestOneBit(long i) {
1619 // HD, Figure 3-1
1620 i |= (i >> 1);
1621 i |= (i >> 2);
1622 i |= (i >> 4);
1623 i |= (i >> 8);
1624 i |= (i >> 16);
1625 i |= (i >> 32);
1626 return i - (i >>> 1);
1627 }
1628
1629 /**
1630 * Returns a {@code long} value with at most a single one-bit, in the
1631 * position of the lowest-order ("rightmost") one-bit in the specified
1632 * {@code long} value. Returns zero if the specified value has no
1633 * one-bits in its two's complement binary representation, that is, if it
1634 * is equal to zero.
1635 *
1636 * @param i the value whose lowest one bit is to be computed
1637 * @return a {@code long} value with a single one-bit, in the position
1638 * of the lowest-order one-bit in the specified value, or zero if
1639 * the specified value is itself equal to zero.
1640 * @since 1.5
1641 */
1642 public static long lowestOneBit(long i) {
1643 // HD, Section 2-1
1644 return i & -i;
1645 }
1646
1647 /**
1648 * Returns the number of zero bits preceding the highest-order
1649 * ("leftmost") one-bit in the two's complement binary representation
1650 * of the specified {@code long} value. Returns 64 if the
1651 * specified value has no one-bits in its two's complement representation,
1652 * in other words if it is equal to zero.
1653 *
1654 * <p>Note that this method is closely related to the logarithm base 2.
1655 * For all positive {@code long} values x:
1656 * <ul>
1657 * <li>floor(log<sub>2</sub>(x)) = {@code 63 - numberOfLeadingZeros(x)}
1658 * <li>ceil(log<sub>2</sub>(x)) = {@code 64 - numberOfLeadingZeros(x - 1)}
1659 * </ul>
1660 *
1661 * @param i the value whose number of leading zeros is to be computed
1662 * @return the number of zero bits preceding the highest-order
1663 * ("leftmost") one-bit in the two's complement binary representation
1664 * of the specified {@code long} value, or 64 if the value
1665 * is equal to zero.
1666 * @since 1.5
1667 */
1668 @HotSpotIntrinsicCandidate
1669 public static int numberOfLeadingZeros(long i) {
1670 // HD, Figure 5-6
1671 if (i == 0)
1672 return 64;
1673 int n = 1;
1674 int x = (int)(i >>> 32);
1675 if (x == 0) { n += 32; x = (int)i; }
1676 if (x >>> 16 == 0) { n += 16; x <<= 16; }
1677 if (x >>> 24 == 0) { n += 8; x <<= 8; }
1678 if (x >>> 28 == 0) { n += 4; x <<= 4; }
1679 if (x >>> 30 == 0) { n += 2; x <<= 2; }
1680 n -= x >>> 31;
1681 return n;
1682 }
1683
1684 /**
1685 * Returns the number of zero bits following the lowest-order ("rightmost")
1686 * one-bit in the two's complement binary representation of the specified
1687 * {@code long} value. Returns 64 if the specified value has no
1688 * one-bits in its two's complement representation, in other words if it is
1689 * equal to zero.
1690 *
1691 * @param i the value whose number of trailing zeros is to be computed
1692 * @return the number of zero bits following the lowest-order ("rightmost")
1693 * one-bit in the two's complement binary representation of the
1694 * specified {@code long} value, or 64 if the value is equal
1695 * to zero.
1696 * @since 1.5
1697 */
1698 @HotSpotIntrinsicCandidate
1699 public static int numberOfTrailingZeros(long i) {
1700 // HD, Figure 5-14
1701 int x, y;
1702 if (i == 0) return 64;
1703 int n = 63;
1704 y = (int)i; if (y != 0) { n = n -32; x = y; } else x = (int)(i>>>32);
1705 y = x <<16; if (y != 0) { n = n -16; x = y; }
1706 y = x << 8; if (y != 0) { n = n - 8; x = y; }
1707 y = x << 4; if (y != 0) { n = n - 4; x = y; }
1708 y = x << 2; if (y != 0) { n = n - 2; x = y; }
1709 return n - ((x << 1) >>> 31);
1710 }
1711
1712 /**
1713 * Returns the number of one-bits in the two's complement binary
1714 * representation of the specified {@code long} value. This function is
1715 * sometimes referred to as the <i>population count</i>.
1716 *
1717 * @param i the value whose bits are to be counted
1718 * @return the number of one-bits in the two's complement binary
1719 * representation of the specified {@code long} value.
1720 * @since 1.5
1721 */
1722 @HotSpotIntrinsicCandidate
1723 public static int bitCount(long i) {
1724 // HD, Figure 5-2
1725 i = i - ((i >>> 1) & 0x5555555555555555L);
1726 i = (i & 0x3333333333333333L) + ((i >>> 2) & 0x3333333333333333L);
1727 i = (i + (i >>> 4)) & 0x0f0f0f0f0f0f0f0fL;
1728 i = i + (i >>> 8);
1729 i = i + (i >>> 16);
1730 i = i + (i >>> 32);
1731 return (int)i & 0x7f;
1732 }
1733
1734 /**
1735 * Returns the value obtained by rotating the two's complement binary
1736 * representation of the specified {@code long} value left by the
1737 * specified number of bits. (Bits shifted out of the left hand, or
1738 * high-order, side reenter on the right, or low-order.)
1739 *
1740 * <p>Note that left rotation with a negative distance is equivalent to
1741 * right rotation: {@code rotateLeft(val, -distance) == rotateRight(val,
1742 * distance)}. Note also that rotation by any multiple of 64 is a
1743 * no-op, so all but the last six bits of the rotation distance can be
1744 * ignored, even if the distance is negative: {@code rotateLeft(val,
1745 * distance) == rotateLeft(val, distance & 0x3F)}.
1746 *
1747 * @param i the value whose bits are to be rotated left
1748 * @param distance the number of bit positions to rotate left
1749 * @return the value obtained by rotating the two's complement binary
1750 * representation of the specified {@code long} value left by the
1751 * specified number of bits.
1752 * @since 1.5
1753 */
1754 public static long rotateLeft(long i, int distance) {
1755 return (i << distance) | (i >>> -distance);
1756 }
1757
1758 /**
1759 * Returns the value obtained by rotating the two's complement binary
1760 * representation of the specified {@code long} value right by the
1761 * specified number of bits. (Bits shifted out of the right hand, or
1762 * low-order, side reenter on the left, or high-order.)
1763 *
1764 * <p>Note that right rotation with a negative distance is equivalent to
1765 * left rotation: {@code rotateRight(val, -distance) == rotateLeft(val,
1766 * distance)}. Note also that rotation by any multiple of 64 is a
1767 * no-op, so all but the last six bits of the rotation distance can be
1768 * ignored, even if the distance is negative: {@code rotateRight(val,
1769 * distance) == rotateRight(val, distance & 0x3F)}.
1770 *
1771 * @param i the value whose bits are to be rotated right
1772 * @param distance the number of bit positions to rotate right
1773 * @return the value obtained by rotating the two's complement binary
1774 * representation of the specified {@code long} value right by the
1775 * specified number of bits.
1776 * @since 1.5
1777 */
1778 public static long rotateRight(long i, int distance) {
1779 return (i >>> distance) | (i << -distance);
1780 }
1781
1782 /**
1783 * Returns the value obtained by reversing the order of the bits in the
1784 * two's complement binary representation of the specified {@code long}
1785 * value.
1786 *
1787 * @param i the value to be reversed
1788 * @return the value obtained by reversing order of the bits in the
1789 * specified {@code long} value.
1790 * @since 1.5
1791 */
1792 public static long reverse(long i) {
1793 // HD, Figure 7-1
1794 i = (i & 0x5555555555555555L) << 1 | (i >>> 1) & 0x5555555555555555L;
1795 i = (i & 0x3333333333333333L) << 2 | (i >>> 2) & 0x3333333333333333L;
1796 i = (i & 0x0f0f0f0f0f0f0f0fL) << 4 | (i >>> 4) & 0x0f0f0f0f0f0f0f0fL;
1797 i = (i & 0x00ff00ff00ff00ffL) << 8 | (i >>> 8) & 0x00ff00ff00ff00ffL;
1798 i = (i << 48) | ((i & 0xffff0000L) << 16) |
1799 ((i >>> 16) & 0xffff0000L) | (i >>> 48);
1800 return i;
1801 }
1802
1803 /**
1804 * Returns the signum function of the specified {@code long} value. (The
1805 * return value is -1 if the specified value is negative; 0 if the
1806 * specified value is zero; and 1 if the specified value is positive.)
1807 *
1808 * @param i the value whose signum is to be computed
1809 * @return the signum function of the specified {@code long} value.
1810 * @since 1.5
1811 */
1812 public static int signum(long i) {
1813 // HD, Section 2-7
1814 return (int) ((i >> 63) | (-i >>> 63));
1815 }
1816
1817 /**
1818 * Returns the value obtained by reversing the order of the bytes in the
1819 * two's complement representation of the specified {@code long} value.
1820 *
1821 * @param i the value whose bytes are to be reversed
1822 * @return the value obtained by reversing the bytes in the specified
1823 * {@code long} value.
1824 * @since 1.5
1825 */
1826 @HotSpotIntrinsicCandidate
1827 public static long reverseBytes(long i) {
1828 i = (i & 0x00ff00ff00ff00ffL) << 8 | (i >>> 8) & 0x00ff00ff00ff00ffL;
1829 return (i << 48) | ((i & 0xffff0000L) << 16) |
1830 ((i >>> 16) & 0xffff0000L) | (i >>> 48);
1831 }
1832
1833 /**
1834 * Adds two {@code long} values together as per the + operator.
1835 *
1836 * @param a the first operand
1837 * @param b the second operand
1838 * @return the sum of {@code a} and {@code b}
1839 * @see java.util.function.BinaryOperator
1840 * @since 1.8
1841 */
1842 public static long sum(long a, long b) {
1843 return a + b;
1844 }
1845
1846 /**
1847 * Returns the greater of two {@code long} values
1848 * as if by calling {@link Math#max(long, long) Math.max}.
1849 *
1850 * @param a the first operand
1851 * @param b the second operand
1852 * @return the greater of {@code a} and {@code b}
1853 * @see java.util.function.BinaryOperator
1854 * @since 1.8
1855 */
1856 public static long max(long a, long b) {
1857 return Math.max(a, b);
1858 }
1859
1860 /**
1861 * Returns the smaller of two {@code long} values
1862 * as if by calling {@link Math#min(long, long) Math.min}.
1863 *
1864 * @param a the first operand
1865 * @param b the second operand
1866 * @return the smaller of {@code a} and {@code b}
1867 * @see java.util.function.BinaryOperator
1868 * @since 1.8
1869 */
1870 public static long min(long a, long b) {
1871 return Math.min(a, b);
1872 }
1873
1874 /** use serialVersionUID from JDK 1.0.2 for interoperability */
1875 @Native private static final long serialVersionUID = 4290774380558885855L;
1876 }