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 * Returns a string representation of the first argument in the
80 * radix specified by the second argument.
81 *
82 * <p>If the radix is smaller than {@code Character.MIN_RADIX}
83 * or larger than {@code Character.MAX_RADIX}, then the radix
84 * {@code 10} is used instead.
85 *
86 * <p>If the first argument is negative, the first element of the
87 * result is the ASCII minus sign {@code '-'}
88 * ({@code '\u005Cu002d'}). If the first argument is not
89 * negative, no sign character appears in the result.
90 *
91 * <p>The remaining characters of the result represent the magnitude
92 * of the first argument. If the magnitude is zero, it is
93 * represented by a single zero character {@code '0'}
94 * ({@code '\u005Cu0030'}); otherwise, the first character of
95 * the representation of the magnitude will not be the zero
96 * character. The following ASCII characters are used as digits:
97 *
98 * <blockquote>
99 * {@code 0123456789abcdefghijklmnopqrstuvwxyz}
100 * </blockquote>
101 *
102 * These are {@code '\u005Cu0030'} through
103 * {@code '\u005Cu0039'} and {@code '\u005Cu0061'} through
104 * {@code '\u005Cu007a'}. If {@code radix} is
105 * <var>N</var>, then the first <var>N</var> of these characters
106 * are used as radix-<var>N</var> digits in the order shown. Thus,
107 * the digits for hexadecimal (radix 16) are
108 * {@code 0123456789abcdef}. If uppercase letters are
109 * desired, the {@link java.lang.String#toUpperCase()} method may
110 * be called on the result:
111 *
112 * <blockquote>
113 * {@code Long.toString(n, 16).toUpperCase()}
114 * </blockquote>
115 *
116 * @param i a {@code long} to be converted to a string.
117 * @param radix the radix to use in the string representation.
118 * @return a string representation of the argument in the specified radix.
119 * @see java.lang.Character#MAX_RADIX
120 * @see java.lang.Character#MIN_RADIX
121 */
122 public static String toString(long i, int radix) {
123 if (radix < Character.MIN_RADIX || radix > Character.MAX_RADIX)
124 radix = 10;
125 if (radix == 10)
126 return toString(i);
127 char[] buf = new char[65];
128 int charPos = 64;
129 boolean negative = (i < 0);
130
131 if (!negative) {
132 i = -i;
133 }
134
135 while (i <= -radix) {
136 buf[charPos--] = Integer.digits[(int)(-(i % radix))];
137 i = i / radix;
138 }
139 buf[charPos] = Integer.digits[(int)(-i)];
140
141 if (negative) {
142 buf[--charPos] = '-';
143 }
144
145 return new String(buf, charPos, (65 - charPos));
146 }
147
148 /**
149 * Returns a string representation of the first argument as an
150 * unsigned integer value in the radix specified by the second
151 * argument.
152 *
153 * <p>If the radix is smaller than {@code Character.MIN_RADIX}
154 * or larger than {@code Character.MAX_RADIX}, then the radix
155 * {@code 10} is used instead.
156 *
157 * <p>Note that since the first argument is treated as an unsigned
158 * value, no leading sign character is printed.
159 *
160 * <p>If the magnitude is zero, it is represented by a single zero
161 * character {@code '0'} ({@code '\u005Cu0030'}); otherwise,
162 * the first character of the representation of the magnitude will
163 * not be the zero character.
164 *
165 * <p>The behavior of radixes and the characters used as digits
166 * are the same as {@link #toString(long, int) toString}.
167 *
168 * @param i an integer to be converted to an unsigned string.
169 * @param radix the radix to use in the string representation.
170 * @return an unsigned string representation of the argument in the specified radix.
171 * @see #toString(long, int)
172 * @since 1.8
173 */
174 public static String toUnsignedString(long i, int radix) {
175 if (i >= 0)
176 return toString(i, radix);
177 else {
178 switch (radix) {
179 case 2:
180 return toBinaryString(i);
181
182 case 4:
183 return toUnsignedString0(i, 2);
184
185 case 8:
186 return toOctalString(i);
187
188 case 10:
189 /*
190 * We can get the effect of an unsigned division by 10
191 * on a long value by first shifting right, yielding a
192 * positive value, and then dividing by 5. This
193 * allows the last digit and preceding digits to be
194 * isolated more quickly than by an initial conversion
195 * to BigInteger.
196 */
197 long quot = (i >>> 1) / 5;
198 long rem = i - quot * 10;
199 return toString(quot) + rem;
200
201 case 16:
202 return toHexString(i);
203
204 case 32:
205 return toUnsignedString0(i, 5);
206
207 default:
208 return toUnsignedBigInteger(i).toString(radix);
209 }
210 }
211 }
212
213 /**
214 * Return a BigInteger equal to the unsigned value of the
215 * argument.
216 */
217 private static BigInteger toUnsignedBigInteger(long i) {
218 if (i >= 0L)
219 return BigInteger.valueOf(i);
220 else {
221 int upper = (int) (i >>> 32);
222 int lower = (int) i;
223
224 // return (upper << 32) + lower
225 return (BigInteger.valueOf(Integer.toUnsignedLong(upper))).shiftLeft(32).
226 add(BigInteger.valueOf(Integer.toUnsignedLong(lower)));
227 }
228 }
229
230 /**
231 * Returns a string representation of the {@code long}
232 * argument as an unsigned integer in base 16.
233 *
234 * <p>The unsigned {@code long} value is the argument plus
235 * 2<sup>64</sup> if the argument is negative; otherwise, it is
236 * equal to the argument. This value is converted to a string of
237 * ASCII digits in hexadecimal (base 16) with no extra
238 * leading {@code 0}s.
239 *
240 * <p>The value of the argument can be recovered from the returned
241 * string {@code s} by calling {@link
242 * Long#parseUnsignedLong(String, int) Long.parseUnsignedLong(s,
243 * 16)}.
244 *
245 * <p>If the unsigned magnitude is zero, it is represented by a
246 * single zero character {@code '0'} ({@code '\u005Cu0030'});
247 * otherwise, the first character of the representation of the
248 * unsigned magnitude will not be the zero character. The
249 * following characters are used as hexadecimal digits:
250 *
251 * <blockquote>
252 * {@code 0123456789abcdef}
253 * </blockquote>
254 *
255 * These are the characters {@code '\u005Cu0030'} through
256 * {@code '\u005Cu0039'} and {@code '\u005Cu0061'} through
257 * {@code '\u005Cu0066'}. If uppercase letters are desired,
258 * the {@link java.lang.String#toUpperCase()} method may be called
259 * on the result:
260 *
261 * <blockquote>
262 * {@code Long.toHexString(n).toUpperCase()}
263 * </blockquote>
264 *
265 * @param i a {@code long} to be converted to a string.
266 * @return the string representation of the unsigned {@code long}
267 * value represented by the argument in hexadecimal
268 * (base 16).
269 * @see #parseUnsignedLong(String, int)
270 * @see #toUnsignedString(long, int)
271 * @since 1.0.2
272 */
273 public static String toHexString(long i) {
274 return toUnsignedString0(i, 4);
275 }
276
277 /**
278 * Returns a string representation of the {@code long}
279 * argument as an unsigned integer in base 8.
280 *
281 * <p>The unsigned {@code long} value is the argument plus
282 * 2<sup>64</sup> if the argument is negative; otherwise, it is
283 * equal to the argument. This value is converted to a string of
284 * ASCII digits in octal (base 8) with no extra leading
285 * {@code 0}s.
286 *
287 * <p>The value of the argument can be recovered from the returned
288 * string {@code s} by calling {@link
289 * Long#parseUnsignedLong(String, int) Long.parseUnsignedLong(s,
290 * 8)}.
291 *
292 * <p>If the unsigned magnitude is zero, it is represented by a
293 * single zero character {@code '0'} ({@code '\u005Cu0030'});
294 * otherwise, the first character of the representation of the
295 * unsigned magnitude will not be the zero character. The
296 * following characters are used as octal digits:
297 *
298 * <blockquote>
299 * {@code 01234567}
300 * </blockquote>
301 *
302 * These are the characters {@code '\u005Cu0030'} through
303 * {@code '\u005Cu0037'}.
304 *
305 * @param i a {@code long} to be converted to a string.
306 * @return the string representation of the unsigned {@code long}
307 * value represented by the argument in octal (base 8).
308 * @see #parseUnsignedLong(String, int)
309 * @see #toUnsignedString(long, int)
310 * @since 1.0.2
311 */
312 public static String toOctalString(long i) {
313 return toUnsignedString0(i, 3);
314 }
315
316 /**
317 * Returns a string representation of the {@code long}
318 * argument as an unsigned integer in base 2.
319 *
320 * <p>The unsigned {@code long} value is the argument plus
321 * 2<sup>64</sup> if the argument is negative; otherwise, it is
322 * equal to the argument. This value is converted to a string of
323 * ASCII digits in binary (base 2) with no extra leading
324 * {@code 0}s.
325 *
326 * <p>The value of the argument can be recovered from the returned
327 * string {@code s} by calling {@link
328 * Long#parseUnsignedLong(String, int) Long.parseUnsignedLong(s,
329 * 2)}.
330 *
331 * <p>If the unsigned magnitude is zero, it is represented by a
332 * single zero character {@code '0'} ({@code '\u005Cu0030'});
333 * otherwise, the first character of the representation of the
334 * unsigned magnitude will not be the zero character. The
335 * characters {@code '0'} ({@code '\u005Cu0030'}) and {@code
336 * '1'} ({@code '\u005Cu0031'}) are used as binary digits.
337 *
338 * @param i a {@code long} to be converted to a string.
339 * @return the string representation of the unsigned {@code long}
340 * value represented by the argument in binary (base 2).
341 * @see #parseUnsignedLong(String, int)
342 * @see #toUnsignedString(long, int)
343 * @since 1.0.2
344 */
345 public static String toBinaryString(long i) {
346 return toUnsignedString0(i, 1);
347 }
348
349 /**
350 * Format a long (treated as unsigned) into a String.
351 * @param val the value to format
352 * @param shift the log2 of the base to format in (4 for hex, 3 for octal, 1 for binary)
353 */
354 static String toUnsignedString0(long val, int shift) {
355 // assert shift > 0 && shift <=5 : "Illegal shift value";
356 int mag = Long.SIZE - Long.numberOfLeadingZeros(val);
357 int chars = Math.max(((mag + (shift - 1)) / shift), 1);
358 char[] buf = new char[chars];
359
360 formatUnsignedLong(val, shift, buf, 0, chars);
361 return new String(buf, true);
362 }
363
364 /**
365 * Format a long (treated as unsigned) into a character buffer. If
366 * {@code len} exceeds the formatted ASCII representation of {@code val},
367 * {@code buf} will be padded with leading zeroes.
368 *
369 * @param val the unsigned long to format
370 * @param shift the log2 of the base to format in (4 for hex, 3 for octal, 1 for binary)
371 * @param buf the character buffer to write to
372 * @param offset the offset in the destination buffer to start at
373 * @param len the number of characters to write
374 */
375 static void formatUnsignedLong(long val, int shift, char[] buf, int offset, int len) {
376 // assert shift > 0 && shift <=5 : "Illegal shift value";
377 // assert offset >= 0 && offset < buf.length : "illegal offset";
378 // assert len > 0 && (offset + len) <= buf.length : "illegal length";
379 int charPos = offset + len;
380 int radix = 1 << shift;
381 int mask = radix - 1;
382 do {
383 buf[--charPos] = Integer.digits[((int) val) & mask];
384 val >>>= shift;
385 } while (charPos > offset);
386 }
387
388 /**
389 * Returns a {@code String} object representing the specified
390 * {@code long}. The argument is converted to signed decimal
391 * representation and returned as a string, exactly as if the
392 * argument and the radix 10 were given as arguments to the {@link
393 * #toString(long, int)} method.
394 *
395 * @param i a {@code long} to be converted.
396 * @return a string representation of the argument in base 10.
397 */
398 public static String toString(long i) {
399 if (i == Long.MIN_VALUE)
400 return "-9223372036854775808";
401 int size = (i < 0) ? stringSize(-i) + 1 : stringSize(i);
402 char[] buf = new char[size];
403 getChars(i, size, buf);
404 return new String(buf, true);
405 }
406
407 /**
408 * Returns a string representation of the argument as an unsigned
409 * decimal value.
410 *
411 * The argument is converted to unsigned decimal representation
412 * and returned as a string exactly as if the argument and radix
413 * 10 were given as arguments to the {@link #toUnsignedString(long,
414 * int)} method.
415 *
416 * @param i an integer to be converted to an unsigned string.
417 * @return an unsigned string representation of the argument.
418 * @see #toUnsignedString(long, int)
419 * @since 1.8
420 */
421 public static String toUnsignedString(long i) {
422 return toUnsignedString(i, 10);
423 }
424
425 /**
426 * Places characters representing the integer i into the
427 * character array buf. The characters are placed into
428 * the buffer backwards starting with the least significant
429 * digit at the specified index (exclusive), and working
430 * backwards from there.
431 *
432 * Will fail if i == Long.MIN_VALUE
433 */
434 static void getChars(long i, int index, char[] buf) {
435 long q;
436 int r;
437 int charPos = index;
438 char sign = 0;
439
440 if (i < 0) {
441 sign = '-';
442 i = -i;
443 }
444
445 // Get 2 digits/iteration using longs until quotient fits into an int
446 while (i > Integer.MAX_VALUE) {
447 q = i / 100;
448 // really: r = i - (q * 100);
449 r = (int)(i - ((q << 6) + (q << 5) + (q << 2)));
450 i = q;
451 buf[--charPos] = Integer.DigitOnes[r];
452 buf[--charPos] = Integer.DigitTens[r];
453 }
454
455 // Get 2 digits/iteration using ints
456 int q2;
457 int i2 = (int)i;
458 while (i2 >= 65536) {
459 q2 = i2 / 100;
460 // really: r = i2 - (q * 100);
461 r = i2 - ((q2 << 6) + (q2 << 5) + (q2 << 2));
462 i2 = q2;
463 buf[--charPos] = Integer.DigitOnes[r];
464 buf[--charPos] = Integer.DigitTens[r];
465 }
466
467 // Fall thru to fast mode for smaller numbers
468 // assert(i2 <= 65536, i2);
469 for (;;) {
470 q2 = (i2 * 52429) >>> (16+3);
471 r = i2 - ((q2 << 3) + (q2 << 1)); // r = i2-(q2*10) ...
472 buf[--charPos] = Integer.digits[r];
473 i2 = q2;
474 if (i2 == 0) break;
475 }
476 if (sign != 0) {
477 buf[--charPos] = sign;
478 }
479 }
480
481 // Requires positive x
482 static int stringSize(long x) {
483 long p = 10;
484 for (int i=1; i<19; i++) {
485 if (x < p)
486 return i;
487 p = 10*p;
488 }
489 return 19;
490 }
491
492 /**
493 * Parses the string argument as a signed {@code long} in the
494 * radix specified by the second argument. The characters in the
495 * string must all be digits of the specified radix (as determined
496 * by whether {@link java.lang.Character#digit(char, int)} returns
497 * a nonnegative value), except that the first character may be an
498 * ASCII minus sign {@code '-'} ({@code '\u005Cu002D'}) to
499 * indicate a negative value or an ASCII plus sign {@code '+'}
500 * ({@code '\u005Cu002B'}) to indicate a positive value. The
501 * resulting {@code long} value is returned.
502 *
503 * <p>Note that neither the character {@code L}
504 * ({@code '\u005Cu004C'}) nor {@code l}
505 * ({@code '\u005Cu006C'}) is permitted to appear at the end
506 * of the string as a type indicator, as would be permitted in
507 * Java programming language source code - except that either
508 * {@code L} or {@code l} may appear as a digit for a
509 * radix greater than or equal to 22.
510 *
511 * <p>An exception of type {@code NumberFormatException} is
512 * thrown if any of the following situations occurs:
513 * <ul>
514 *
515 * <li>The first argument is {@code null} or is a string of
516 * length zero.
517 *
518 * <li>The {@code radix} is either smaller than {@link
519 * java.lang.Character#MIN_RADIX} or larger than {@link
520 * java.lang.Character#MAX_RADIX}.
521 *
522 * <li>Any character of the string is not a digit of the specified
523 * radix, except that the first character may be a minus sign
524 * {@code '-'} ({@code '\u005Cu002d'}) or plus sign {@code
525 * '+'} ({@code '\u005Cu002B'}) provided that the string is
526 * longer than length 1.
527 *
528 * <li>The value represented by the string is not a value of type
529 * {@code long}.
530 * </ul>
531 *
532 * <p>Examples:
533 * <blockquote><pre>
534 * parseLong("0", 10) returns 0L
535 * parseLong("473", 10) returns 473L
536 * parseLong("+42", 10) returns 42L
537 * parseLong("-0", 10) returns 0L
538 * parseLong("-FF", 16) returns -255L
539 * parseLong("1100110", 2) returns 102L
540 * parseLong("99", 8) throws a NumberFormatException
541 * parseLong("Hazelnut", 10) throws a NumberFormatException
542 * parseLong("Hazelnut", 36) returns 1356099454469L
543 * </pre></blockquote>
544 *
545 * @param s the {@code String} containing the
546 * {@code long} representation to be parsed.
547 * @param radix the radix to be used while parsing {@code s}.
548 * @return the {@code long} represented by the string argument in
549 * the specified radix.
550 * @throws NumberFormatException if the string does not contain a
551 * parsable {@code long}.
552 */
553 public static long parseLong(String s, int radix)
554 throws NumberFormatException
555 {
556 if (s == null) {
557 throw new NumberFormatException("null");
558 }
559
560 if (radix < Character.MIN_RADIX) {
561 throw new NumberFormatException("radix " + radix +
562 " less than Character.MIN_RADIX");
563 }
564 if (radix > Character.MAX_RADIX) {
565 throw new NumberFormatException("radix " + radix +
566 " greater than Character.MAX_RADIX");
567 }
568
569 boolean negative = false;
570 int i = 0, len = s.length();
571 long limit = -Long.MAX_VALUE;
572
573 if (len > 0) {
574 char firstChar = s.charAt(0);
575 if (firstChar < '0') { // Possible leading "+" or "-"
576 if (firstChar == '-') {
577 negative = true;
578 limit = Long.MIN_VALUE;
579 } else if (firstChar != '+') {
580 throw NumberFormatException.forInputString(s);
581 }
582
583 if (len == 1) { // Cannot have lone "+" or "-"
584 throw NumberFormatException.forInputString(s);
585 }
586 i++;
587 }
588 long multmin = limit / radix;
589 long result = 0;
590 while (i < len) {
591 // Accumulating negatively avoids surprises near MAX_VALUE
592 int digit = Character.digit(s.charAt(i++),radix);
593 if (digit < 0 || result < multmin) {
594 throw NumberFormatException.forInputString(s);
595 }
596 result *= radix;
597 if (result < limit + digit) {
598 throw NumberFormatException.forInputString(s);
599 }
600 result -= digit;
601 }
602 return negative ? result : -result;
603 } else {
604 throw NumberFormatException.forInputString(s);
605 }
606 }
607
608 /**
609 * Parses the {@link CharSequence} argument as a signed {@code long} in
610 * the specified {@code radix}, beginning at the specified
611 * {@code beginIndex} and extending to {@code endIndex - 1}.
612 *
613 * <p>The method does not take steps to guard against the
614 * {@code CharSequence} being mutated while parsing.
615 *
616 * @param s the {@code CharSequence} containing the {@code long}
617 * representation to be parsed
618 * @param beginIndex the beginning index, inclusive.
619 * @param endIndex the ending index, exclusive.
620 * @param radix the radix to be used while parsing {@code s}.
621 * @return the signed {@code long} represented by the subsequence in
622 * the specified radix.
623 * @throws NullPointerException if {@code s} is null.
624 * @throws IndexOutOfBoundsException if {@code beginIndex} is
625 * negative, or if {@code beginIndex} is greater than
626 * {@code endIndex} or if {@code endIndex} is greater than
627 * {@code s.length()}.
628 * @throws NumberFormatException if the {@code CharSequence} does not
629 * contain a parsable {@code int} in the specified
630 * {@code radix}, or if {@code radix} is either smaller than
631 * {@link java.lang.Character#MIN_RADIX} or larger than
632 * {@link java.lang.Character#MAX_RADIX}.
633 * @since 1.9
634 */
635 public static long parseLong(CharSequence s, int beginIndex, int endIndex, int radix)
636 throws NumberFormatException {
637 s = Objects.requireNonNull(s);
638
639 if (beginIndex < 0 || beginIndex > endIndex || endIndex > s.length()) {
640 throw new IndexOutOfBoundsException();
641 }
642 if (radix < Character.MIN_RADIX) {
643 throw new NumberFormatException("radix " + radix +
644 " less than Character.MIN_RADIX");
645 }
646 if (radix > Character.MAX_RADIX) {
647 throw new NumberFormatException("radix " + radix +
648 " greater than Character.MAX_RADIX");
649 }
650
651 boolean negative = false;
652 int i = beginIndex;
653 long limit = -Long.MAX_VALUE;
654
655 if (i < endIndex) {
656 char firstChar = s.charAt(i);
657 if (firstChar < '0') { // Possible leading "+" or "-"
658 if (firstChar == '-') {
659 negative = true;
660 limit = Long.MIN_VALUE;
661 } else if (firstChar != '+') {
662 throw NumberFormatException.forCharSequence(s, beginIndex,
663 endIndex, i);
664 }
665 i++;
666 }
667 if (i >= endIndex) { // Cannot have lone "+", "-" or ""
668 throw NumberFormatException.forCharSequence(s, beginIndex,
669 endIndex, i);
670 }
671 long multmin = limit / radix;
672 long result = 0;
673 while (i < endIndex) {
674 // Accumulating negatively avoids surprises near MAX_VALUE
675 int digit = Character.digit(s.charAt(i), radix);
676 if (digit < 0 || result < multmin) {
677 throw NumberFormatException.forCharSequence(s, beginIndex,
678 endIndex, i);
679 }
680 result *= radix;
681 if (result < limit + digit) {
682 throw NumberFormatException.forCharSequence(s, beginIndex,
683 endIndex, i);
684 }
685 i++;
686 result -= digit;
687 }
688 return negative ? result : -result;
689 } else {
690 throw new NumberFormatException("");
691 }
692 }
693
694 /**
695 * Parses the string argument as a signed decimal {@code long}.
696 * The characters in the string must all be decimal digits, except
697 * that the first character may be an ASCII minus sign {@code '-'}
698 * ({@code \u005Cu002D'}) to indicate a negative value or an
699 * ASCII plus sign {@code '+'} ({@code '\u005Cu002B'}) to
700 * indicate a positive value. The resulting {@code long} value is
701 * returned, exactly as if the argument and the radix {@code 10}
702 * were given as arguments to the {@link
703 * #parseLong(java.lang.String, int)} method.
704 *
705 * <p>Note that neither the character {@code L}
706 * ({@code '\u005Cu004C'}) nor {@code l}
707 * ({@code '\u005Cu006C'}) is permitted to appear at the end
708 * of the string as a type indicator, as would be permitted in
709 * Java programming language source code.
710 *
711 * @param s a {@code String} containing the {@code long}
712 * representation to be parsed
713 * @return the {@code long} represented by the argument in
714 * decimal.
715 * @throws NumberFormatException if the string does not contain a
716 * parsable {@code long}.
717 */
718 public static long parseLong(String s) throws NumberFormatException {
719 return parseLong(s, 10);
720 }
721
722 /**
723 * Parses the string argument as an unsigned {@code long} in the
724 * radix specified by the second argument. An unsigned integer
725 * maps the values usually associated with negative numbers to
726 * positive numbers larger than {@code MAX_VALUE}.
727 *
728 * The characters in the string must all be digits of the
729 * specified radix (as determined by whether {@link
730 * java.lang.Character#digit(char, int)} returns a nonnegative
731 * value), except that the first character may be an ASCII plus
732 * sign {@code '+'} ({@code '\u005Cu002B'}). The resulting
733 * integer value is returned.
734 *
735 * <p>An exception of type {@code NumberFormatException} is
736 * thrown if any of the following situations occurs:
737 * <ul>
738 * <li>The first argument is {@code null} or is a string of
739 * length zero.
740 *
741 * <li>The radix is either smaller than
742 * {@link java.lang.Character#MIN_RADIX} or
743 * larger than {@link java.lang.Character#MAX_RADIX}.
744 *
745 * <li>Any character of the string is not a digit of the specified
746 * radix, except that the first character may be a plus sign
747 * {@code '+'} ({@code '\u005Cu002B'}) provided that the
748 * string is longer than length 1.
749 *
750 * <li>The value represented by the string is larger than the
751 * largest unsigned {@code long}, 2<sup>64</sup>-1.
752 *
753 * </ul>
754 *
755 *
756 * @param s the {@code String} containing the unsigned integer
757 * representation to be parsed
758 * @param radix the radix to be used while parsing {@code s}.
759 * @return the unsigned {@code long} represented by the string
760 * argument in the specified radix.
761 * @throws NumberFormatException if the {@code String}
762 * does not contain a parsable {@code long}.
763 * @since 1.8
764 */
765 public static long parseUnsignedLong(String s, int radix)
766 throws NumberFormatException {
767 if (s == null) {
768 throw new NumberFormatException("null");
769 }
770
771 int len = s.length();
772 if (len > 0) {
773 char firstChar = s.charAt(0);
774 if (firstChar == '-') {
775 throw new
776 NumberFormatException(String.format("Illegal leading minus sign " +
777 "on unsigned string %s.", s));
778 } else {
779 if (len <= 12 || // Long.MAX_VALUE in Character.MAX_RADIX is 13 digits
780 (radix == 10 && len <= 18) ) { // Long.MAX_VALUE in base 10 is 19 digits
781 return parseLong(s, radix);
782 }
783
784 // No need for range checks on len due to testing above.
785 long first = parseLong(s, 0, len - 1, radix);
786 int second = Character.digit(s.charAt(len - 1), radix);
787 if (second < 0) {
788 throw new NumberFormatException("Bad digit at end of " + s);
789 }
790 long result = first * radix + second;
791
792 /*
793 * Test leftmost bits of multiprecision extension of first*radix
794 * for overflow. The number of bits needed is defined by
795 * GUARD_BIT = ceil(log2(Character.MAX_RADIX)) + 1 = 7. Then
796 * int guard = radix*(int)(first >>> (64 - GUARD_BIT)) and
797 * overflow is tested by splitting guard in the ranges
798 * guard < 92, 92 <= guard < 128, and 128 <= guard, where
799 * 92 = 128 - Character.MAX_RADIX. Note that guard cannot take
800 * on a value which does not include a prime factor in the legal
801 * radix range.
802 */
803 int guard = radix * (int) (first >>> 57);
804 if (guard >= 128 ||
805 (result >= 0 && guard >= 128 - Character.MAX_RADIX)) {
806 /*
807 * For purposes of exposition, the programmatic statements
808 * below should be taken to be multi-precision, i.e., not
809 * subject to overflow.
810 *
811 * A) Condition guard >= 128:
812 * If guard >= 128 then first*radix >= 2^7 * 2^57 = 2^64
813 * hence always overflow.
814 *
815 * B) Condition guard < 92:
816 * Define left7 = first >>> 57.
817 * Given first = (left7 * 2^57) + (first & (2^57 - 1)) then
818 * result <= (radix*left7)*2^57 + radix*(2^57 - 1) + second.
819 * Thus if radix*left7 < 92, radix <= 36, and second < 36,
820 * then result < 92*2^57 + 36*(2^57 - 1) + 36 = 2^64 hence
821 * never overflow.
822 *
823 * C) Condition 92 <= guard < 128:
824 * first*radix + second >= radix*left7*2^57 + second
825 * so that first*radix + second >= 92*2^57 + 0 > 2^63
826 *
827 * D) Condition guard < 128:
828 * radix*first <= (radix*left7) * 2^57 + radix*(2^57 - 1)
829 * so
830 * radix*first + second <= (radix*left7) * 2^57 + radix*(2^57 - 1) + 36
831 * thus
832 * radix*first + second < 128 * 2^57 + 36*2^57 - radix + 36
833 * whence
834 * radix*first + second < 2^64 + 2^6*2^57 = 2^64 + 2^63
835 *
836 * E) Conditions C, D, and result >= 0:
837 * C and D combined imply the mathematical result
838 * 2^63 < first*radix + second < 2^64 + 2^63. The lower
839 * bound is therefore negative as a signed long, but the
840 * upper bound is too small to overflow again after the
841 * signed long overflows to positive above 2^64 - 1. Hence
842 * result >= 0 implies overflow given C and D.
843 */
844 throw new NumberFormatException(String.format("String value %s exceeds " +
845 "range of unsigned long.", s));
846 }
847 return result;
848 }
849 } else {
850 throw NumberFormatException.forInputString(s);
851 }
852 }
853
854 /**
855 * Parses the {@link CharSequence} argument as an unsigned {@code long} in
856 * the specified {@code radix}, beginning at the specified
857 * {@code beginIndex} and extending to {@code endIndex - 1}.
858 *
859 * <p>The method does not take steps to guard against the
860 * {@code CharSequence} being mutated while parsing.
861 *
862 * @param s the {@code CharSequence} containing the unsigned
863 * {@code long} representation to be parsed
864 * @param beginIndex the beginning index, inclusive.
865 * @param endIndex the ending index, exclusive.
866 * @param radix the radix to be used while parsing {@code s}.
867 * @return the unsigned {@code long} represented by the subsequence in
868 * the specified radix.
869 * @throws NullPointerException if {@code s} is null.
870 * @throws IndexOutOfBoundsException if {@code beginIndex} is
871 * negative, or if {@code beginIndex} is greater than
872 * {@code endIndex} or if {@code endIndex} is greater than
873 * {@code s.length()}.
874 * @throws NumberFormatException if the {@code CharSequence} does not
875 * contain a parsable unsigned {@code long} in the specified
876 * {@code radix}, or if {@code radix} is either smaller than
877 * {@link java.lang.Character#MIN_RADIX} or larger than
878 * {@link java.lang.Character#MAX_RADIX}.
879 * @since 1.9
880 */
881 public static long parseUnsignedLong(CharSequence s, int beginIndex, int endIndex, int radix)
882 throws NumberFormatException {
883 s = Objects.requireNonNull(s);
884
885 if (beginIndex < 0 || beginIndex > endIndex || endIndex > s.length()) {
886 throw new IndexOutOfBoundsException();
887 }
888 int start = beginIndex, len = endIndex - beginIndex;
889
890 if (len > 0) {
891 char firstChar = s.charAt(start);
892 if (firstChar == '-') {
893 throw new NumberFormatException(String.format("Illegal leading minus sign " +
894 "on unsigned string %s.", s.subSequence(start, start + len)));
895 } else {
896 if (len <= 12 || // Long.MAX_VALUE in Character.MAX_RADIX is 13 digits
897 (radix == 10 && len <= 18) ) { // Long.MAX_VALUE in base 10 is 19 digits
898 return parseLong(s, start, start + len, radix);
899 }
900
901 // No need for range checks on end due to testing above.
902 long first = parseLong(s, start, start + len - 1, radix);
903 int second = Character.digit(s.charAt(start + len - 1), radix);
904 if (second < 0) {
905 throw new NumberFormatException("Bad digit at end of " +
906 s.subSequence(start, start + len));
907 }
908 long result = first * radix + second;
909
910 /*
911 * Test leftmost bits of multiprecision extension of first*radix
912 * for overflow. The number of bits needed is defined by
913 * GUARD_BIT = ceil(log2(Character.MAX_RADIX)) + 1 = 7. Then
914 * int guard = radix*(int)(first >>> (64 - GUARD_BIT)) and
915 * overflow is tested by splitting guard in the ranges
916 * guard < 92, 92 <= guard < 128, and 128 <= guard, where
917 * 92 = 128 - Character.MAX_RADIX. Note that guard cannot take
918 * on a value which does not include a prime factor in the legal
919 * radix range.
920 */
921 int guard = radix * (int) (first >>> 57);
922 if (guard >= 128 ||
923 (result >= 0 && guard >= 128 - Character.MAX_RADIX)) {
924 /*
925 * For purposes of exposition, the programmatic statements
926 * below should be taken to be multi-precision, i.e., not
927 * subject to overflow.
928 *
929 * A) Condition guard >= 128:
930 * If guard >= 128 then first*radix >= 2^7 * 2^57 = 2^64
931 * hence always overflow.
932 *
933 * B) Condition guard < 92:
934 * Define left7 = first >>> 57.
935 * Given first = (left7 * 2^57) + (first & (2^57 - 1)) then
936 * result <= (radix*left7)*2^57 + radix*(2^57 - 1) + second.
937 * Thus if radix*left7 < 92, radix <= 36, and second < 36,
938 * then result < 92*2^57 + 36*(2^57 - 1) + 36 = 2^64 hence
939 * never overflow.
940 *
941 * C) Condition 92 <= guard < 128:
942 * first*radix + second >= radix*left7*2^57 + second
943 * so that first*radix + second >= 92*2^57 + 0 > 2^63
944 *
945 * D) Condition guard < 128:
946 * radix*first <= (radix*left7) * 2^57 + radix*(2^57 - 1)
947 * so
948 * radix*first + second <= (radix*left7) * 2^57 + radix*(2^57 - 1) + 36
949 * thus
950 * radix*first + second < 128 * 2^57 + 36*2^57 - radix + 36
951 * whence
952 * radix*first + second < 2^64 + 2^6*2^57 = 2^64 + 2^63
953 *
954 * E) Conditions C, D, and result >= 0:
955 * C and D combined imply the mathematical result
956 * 2^63 < first*radix + second < 2^64 + 2^63. The lower
957 * bound is therefore negative as a signed long, but the
958 * upper bound is too small to overflow again after the
959 * signed long overflows to positive above 2^64 - 1. Hence
960 * result >= 0 implies overflow given C and D.
961 */
962 throw new NumberFormatException(String.format("String value %s exceeds " +
963 "range of unsigned long.", s.subSequence(start, start + len)));
964 }
965 return result;
966 }
967 } else {
968 throw NumberFormatException.forInputString("");
969 }
970 }
971
972 /**
973 * Parses the string argument as an unsigned decimal {@code long}. The
974 * characters in the string must all be decimal digits, except
975 * that the first character may be an ASCII plus sign {@code
976 * '+'} ({@code '\u005Cu002B'}). The resulting integer value
977 * is returned, exactly as if the argument and the radix 10 were
978 * given as arguments to the {@link
979 * #parseUnsignedLong(java.lang.String, int)} method.
980 *
981 * @param s a {@code String} containing the unsigned {@code long}
982 * representation to be parsed
983 * @return the unsigned {@code long} value represented by the decimal string argument
984 * @throws NumberFormatException if the string does not contain a
985 * parsable unsigned integer.
986 * @since 1.8
987 */
988 public static long parseUnsignedLong(String s) throws NumberFormatException {
989 return parseUnsignedLong(s, 10);
990 }
991
992 /**
993 * Returns a {@code Long} object holding the value
994 * extracted from the specified {@code String} when parsed
995 * with the radix given by the second argument. The first
996 * argument is interpreted as representing a signed
997 * {@code long} in the radix specified by the second
998 * argument, exactly as if the arguments were given to the {@link
999 * #parseLong(java.lang.String, int)} method. The result is a
1000 * {@code Long} object that represents the {@code long}
1001 * value specified by the string.
1002 *
1003 * <p>In other words, this method returns a {@code Long} object equal
1004 * to the value of:
1005 *
1006 * <blockquote>
1007 * {@code new Long(Long.parseLong(s, radix))}
1008 * </blockquote>
1009 *
1010 * @param s the string to be parsed
1011 * @param radix the radix to be used in interpreting {@code s}
1012 * @return a {@code Long} object holding the value
1013 * represented by the string argument in the specified
1014 * radix.
1015 * @throws NumberFormatException If the {@code String} does not
1016 * contain a parsable {@code long}.
1017 */
1018 public static Long valueOf(String s, int radix) throws NumberFormatException {
1019 return Long.valueOf(parseLong(s, radix));
1020 }
1021
1022 /**
1023 * Returns a {@code Long} object holding the value
1024 * of the specified {@code String}. The argument is
1025 * interpreted as representing a signed decimal {@code long},
1026 * exactly as if the argument were given to the {@link
1027 * #parseLong(java.lang.String)} method. The result is a
1028 * {@code Long} object that represents the integer value
1029 * specified by the string.
1030 *
1031 * <p>In other words, this method returns a {@code Long} object
1032 * equal to the value of:
1033 *
1034 * <blockquote>
1035 * {@code new Long(Long.parseLong(s))}
1036 * </blockquote>
1037 *
1038 * @param s the string to be parsed.
1039 * @return a {@code Long} object holding the value
1040 * represented by the string argument.
1041 * @throws NumberFormatException If the string cannot be parsed
1042 * as a {@code long}.
1043 */
1044 public static Long valueOf(String s) throws NumberFormatException
1045 {
1046 return Long.valueOf(parseLong(s, 10));
1047 }
1048
1049 private static class LongCache {
1050 private LongCache(){}
1051
1052 static final Long cache[] = new Long[-(-128) + 127 + 1];
1053
1054 static {
1055 for(int i = 0; i < cache.length; i++)
1056 cache[i] = new Long(i - 128);
1057 }
1058 }
1059
1060 /**
1061 * Returns a {@code Long} instance representing the specified
1062 * {@code long} value.
1063 * If a new {@code Long} instance is not required, this method
1064 * should generally be used in preference to the constructor
1065 * {@link #Long(long)}, as this method is likely to yield
1066 * significantly better space and time performance by caching
1067 * frequently requested values.
1068 *
1069 * Note that unlike the {@linkplain Integer#valueOf(int)
1070 * corresponding method} in the {@code Integer} class, this method
1071 * is <em>not</em> required to cache values within a particular
1072 * range.
1073 *
1074 * @param l a long value.
1075 * @return a {@code Long} instance representing {@code l}.
1076 * @since 1.5
1077 */
1078 @HotSpotIntrinsicCandidate
1079 public static Long valueOf(long l) {
1080 final int offset = 128;
1081 if (l >= -128 && l <= 127) { // will cache
1082 return LongCache.cache[(int)l + offset];
1083 }
1084 return new Long(l);
1085 }
1086
1087 /**
1088 * Decodes a {@code String} into a {@code Long}.
1089 * Accepts decimal, hexadecimal, and octal numbers given by the
1090 * following grammar:
1091 *
1092 * <blockquote>
1093 * <dl>
1094 * <dt><i>DecodableString:</i>
1095 * <dd><i>Sign<sub>opt</sub> DecimalNumeral</i>
1096 * <dd><i>Sign<sub>opt</sub></i> {@code 0x} <i>HexDigits</i>
1097 * <dd><i>Sign<sub>opt</sub></i> {@code 0X} <i>HexDigits</i>
1098 * <dd><i>Sign<sub>opt</sub></i> {@code #} <i>HexDigits</i>
1099 * <dd><i>Sign<sub>opt</sub></i> {@code 0} <i>OctalDigits</i>
1100 *
1101 * <dt><i>Sign:</i>
1102 * <dd>{@code -}
1103 * <dd>{@code +}
1104 * </dl>
1105 * </blockquote>
1106 *
1107 * <i>DecimalNumeral</i>, <i>HexDigits</i>, and <i>OctalDigits</i>
1108 * are as defined in section 3.10.1 of
1109 * <cite>The Java™ Language Specification</cite>,
1110 * except that underscores are not accepted between digits.
1111 *
1112 * <p>The sequence of characters following an optional
1113 * sign and/or radix specifier ("{@code 0x}", "{@code 0X}",
1114 * "{@code #}", or leading zero) is parsed as by the {@code
1115 * Long.parseLong} method with the indicated radix (10, 16, or 8).
1116 * This sequence of characters must represent a positive value or
1117 * a {@link NumberFormatException} will be thrown. The result is
1118 * negated if first character of the specified {@code String} is
1119 * the minus sign. No whitespace characters are permitted in the
1120 * {@code String}.
1121 *
1122 * @param nm the {@code String} to decode.
1123 * @return a {@code Long} object holding the {@code long}
1124 * value represented by {@code nm}
1125 * @throws NumberFormatException if the {@code String} does not
1126 * contain a parsable {@code long}.
1127 * @see java.lang.Long#parseLong(String, int)
1128 * @since 1.2
1129 */
1130 public static Long decode(String nm) throws NumberFormatException {
1131 int radix = 10;
1132 int index = 0;
1133 boolean negative = false;
1134 Long result;
1135
1136 if (nm.length() == 0)
1137 throw new NumberFormatException("Zero length string");
1138 char firstChar = nm.charAt(0);
1139 // Handle sign, if present
1140 if (firstChar == '-') {
1141 negative = true;
1142 index++;
1143 } else if (firstChar == '+')
1144 index++;
1145
1146 // Handle radix specifier, if present
1147 if (nm.startsWith("0x", index) || nm.startsWith("0X", index)) {
1148 index += 2;
1149 radix = 16;
1150 }
1151 else if (nm.startsWith("#", index)) {
1152 index ++;
1153 radix = 16;
1154 }
1155 else if (nm.startsWith("0", index) && nm.length() > 1 + index) {
1156 index ++;
1157 radix = 8;
1158 }
1159
1160 if (nm.startsWith("-", index) || nm.startsWith("+", index))
1161 throw new NumberFormatException("Sign character in wrong position");
1162
1163 try {
1164 result = Long.valueOf(nm.substring(index), radix);
1165 result = negative ? Long.valueOf(-result.longValue()) : result;
1166 } catch (NumberFormatException e) {
1167 // If number is Long.MIN_VALUE, we'll end up here. The next line
1168 // handles this case, and causes any genuine format error to be
1169 // rethrown.
1170 String constant = negative ? ("-" + nm.substring(index))
1171 : nm.substring(index);
1172 result = Long.valueOf(constant, radix);
1173 }
1174 return result;
1175 }
1176
1177 /**
1178 * The value of the {@code Long}.
1179 *
1180 * @serial
1181 */
1182 private final long value;
1183
1184 /**
1185 * Constructs a newly allocated {@code Long} object that
1186 * represents the specified {@code long} argument.
1187 *
1188 * @param value the value to be represented by the
1189 * {@code Long} object.
1190 */
1191 public Long(long value) {
1192 this.value = value;
1193 }
1194
1195 /**
1196 * Constructs a newly allocated {@code Long} object that
1197 * represents the {@code long} value indicated by the
1198 * {@code String} parameter. The string is converted to a
1199 * {@code long} value in exactly the manner used by the
1200 * {@code parseLong} method for radix 10.
1201 *
1202 * @param s the {@code String} to be converted to a
1203 * {@code Long}.
1204 * @throws NumberFormatException if the {@code String} does not
1205 * contain a parsable {@code long}.
1206 * @see java.lang.Long#parseLong(java.lang.String, int)
1207 */
1208 public Long(String s) throws NumberFormatException {
1209 this.value = parseLong(s, 10);
1210 }
1211
1212 /**
1213 * Returns the value of this {@code Long} as a {@code byte} after
1214 * a narrowing primitive conversion.
1215 * @jls 5.1.3 Narrowing Primitive Conversions
1216 */
1217 public byte byteValue() {
1218 return (byte)value;
1219 }
1220
1221 /**
1222 * Returns the value of this {@code Long} as a {@code short} after
1223 * a narrowing primitive conversion.
1224 * @jls 5.1.3 Narrowing Primitive Conversions
1225 */
1226 public short shortValue() {
1227 return (short)value;
1228 }
1229
1230 /**
1231 * Returns the value of this {@code Long} as an {@code int} after
1232 * a narrowing primitive conversion.
1233 * @jls 5.1.3 Narrowing Primitive Conversions
1234 */
1235 public int intValue() {
1236 return (int)value;
1237 }
1238
1239 /**
1240 * Returns the value of this {@code Long} as a
1241 * {@code long} value.
1242 */
1243 @HotSpotIntrinsicCandidate
1244 public long longValue() {
1245 return value;
1246 }
1247
1248 /**
1249 * Returns the value of this {@code Long} as a {@code float} after
1250 * a widening primitive conversion.
1251 * @jls 5.1.2 Widening Primitive Conversions
1252 */
1253 public float floatValue() {
1254 return (float)value;
1255 }
1256
1257 /**
1258 * Returns the value of this {@code Long} as a {@code double}
1259 * after a widening primitive conversion.
1260 * @jls 5.1.2 Widening Primitive Conversions
1261 */
1262 public double doubleValue() {
1263 return (double)value;
1264 }
1265
1266 /**
1267 * Returns a {@code String} object representing this
1268 * {@code Long}'s value. The value is converted to signed
1269 * decimal representation and returned as a string, exactly as if
1270 * the {@code long} value were given as an argument to the
1271 * {@link java.lang.Long#toString(long)} method.
1272 *
1273 * @return a string representation of the value of this object in
1274 * base 10.
1275 */
1276 public String toString() {
1277 return toString(value);
1278 }
1279
1280 /**
1281 * Returns a hash code for this {@code Long}. The result is
1282 * the exclusive OR of the two halves of the primitive
1283 * {@code long} value held by this {@code Long}
1284 * object. That is, the hashcode is the value of the expression:
1285 *
1286 * <blockquote>
1287 * {@code (int)(this.longValue()^(this.longValue()>>>32))}
1288 * </blockquote>
1289 *
1290 * @return a hash code value for this object.
1291 */
1292 @Override
1293 public int hashCode() {
1294 return Long.hashCode(value);
1295 }
1296
1297 /**
1298 * Returns a hash code for a {@code long} value; compatible with
1299 * {@code Long.hashCode()}.
1300 *
1301 * @param value the value to hash
1302 * @return a hash code value for a {@code long} value.
1303 * @since 1.8
1304 */
1305 public static int hashCode(long value) {
1306 return (int)(value ^ (value >>> 32));
1307 }
1308
1309 /**
1310 * Compares this object to the specified object. The result is
1311 * {@code true} if and only if the argument is not
1312 * {@code null} and is a {@code Long} object that
1313 * contains the same {@code long} value as this object.
1314 *
1315 * @param obj the object to compare with.
1316 * @return {@code true} if the objects are the same;
1317 * {@code false} otherwise.
1318 */
1319 public boolean equals(Object obj) {
1320 if (obj instanceof Long) {
1321 return value == ((Long)obj).longValue();
1322 }
1323 return false;
1324 }
1325
1326 /**
1327 * Determines the {@code long} value of the system property
1328 * with the specified name.
1329 *
1330 * <p>The first argument is treated as the name of a system
1331 * property. System properties are accessible through the {@link
1332 * java.lang.System#getProperty(java.lang.String)} method. The
1333 * string value of this property is then interpreted as a {@code
1334 * long} value using the grammar supported by {@link Long#decode decode}
1335 * and a {@code Long} object representing this value is returned.
1336 *
1337 * <p>If there is no property with the specified name, if the
1338 * specified name is empty or {@code null}, or if the property
1339 * does not have the correct numeric format, then {@code null} is
1340 * returned.
1341 *
1342 * <p>In other words, this method returns a {@code Long} object
1343 * equal to the value of:
1344 *
1345 * <blockquote>
1346 * {@code getLong(nm, null)}
1347 * </blockquote>
1348 *
1349 * @param nm property name.
1350 * @return the {@code Long} value of the property.
1351 * @throws SecurityException for the same reasons as
1352 * {@link System#getProperty(String) System.getProperty}
1353 * @see java.lang.System#getProperty(java.lang.String)
1354 * @see java.lang.System#getProperty(java.lang.String, java.lang.String)
1355 */
1356 public static Long getLong(String nm) {
1357 return getLong(nm, null);
1358 }
1359
1360 /**
1361 * Determines the {@code long} value of the system property
1362 * with the specified name.
1363 *
1364 * <p>The first argument is treated as the name of a system
1365 * property. System properties are accessible through the {@link
1366 * java.lang.System#getProperty(java.lang.String)} method. The
1367 * string value of this property is then interpreted as a {@code
1368 * long} value using the grammar supported by {@link Long#decode decode}
1369 * and a {@code Long} object representing this value is returned.
1370 *
1371 * <p>The second argument is the default value. A {@code Long} object
1372 * that represents the value of the second argument is returned if there
1373 * is no property of the specified name, if the property does not have
1374 * the correct numeric format, or if the specified name is empty or null.
1375 *
1376 * <p>In other words, this method returns a {@code Long} object equal
1377 * to the value of:
1378 *
1379 * <blockquote>
1380 * {@code getLong(nm, new Long(val))}
1381 * </blockquote>
1382 *
1383 * but in practice it may be implemented in a manner such as:
1384 *
1385 * <blockquote><pre>
1386 * Long result = getLong(nm, null);
1387 * return (result == null) ? new Long(val) : result;
1388 * </pre></blockquote>
1389 *
1390 * to avoid the unnecessary allocation of a {@code Long} object when
1391 * the default value is not needed.
1392 *
1393 * @param nm property name.
1394 * @param val default value.
1395 * @return the {@code Long} value of the property.
1396 * @throws SecurityException for the same reasons as
1397 * {@link System#getProperty(String) System.getProperty}
1398 * @see java.lang.System#getProperty(java.lang.String)
1399 * @see java.lang.System#getProperty(java.lang.String, java.lang.String)
1400 */
1401 public static Long getLong(String nm, long val) {
1402 Long result = Long.getLong(nm, null);
1403 return (result == null) ? Long.valueOf(val) : result;
1404 }
1405
1406 /**
1407 * Returns the {@code long} value of the system property with
1408 * the specified name. The first argument is treated as the name
1409 * of a system property. System properties are accessible through
1410 * the {@link java.lang.System#getProperty(java.lang.String)}
1411 * method. The string value of this property is then interpreted
1412 * as a {@code long} value, as per the
1413 * {@link Long#decode decode} method, and a {@code Long} object
1414 * representing this value is returned; in summary:
1415 *
1416 * <ul>
1417 * <li>If the property value begins with the two ASCII characters
1418 * {@code 0x} or the ASCII character {@code #}, not followed by
1419 * a minus sign, then the rest of it is parsed as a hexadecimal integer
1420 * exactly as for the method {@link #valueOf(java.lang.String, int)}
1421 * with radix 16.
1422 * <li>If the property value begins with the ASCII character
1423 * {@code 0} followed by another character, it is parsed as
1424 * an octal integer exactly as by the method {@link
1425 * #valueOf(java.lang.String, int)} with radix 8.
1426 * <li>Otherwise the property value is parsed as a decimal
1427 * integer exactly as by the method
1428 * {@link #valueOf(java.lang.String, int)} with radix 10.
1429 * </ul>
1430 *
1431 * <p>Note that, in every case, neither {@code L}
1432 * ({@code '\u005Cu004C'}) nor {@code l}
1433 * ({@code '\u005Cu006C'}) is permitted to appear at the end
1434 * of the property value as a type indicator, as would be
1435 * permitted in Java programming language source code.
1436 *
1437 * <p>The second argument is the default value. The default value is
1438 * returned if there is no property of the specified name, if the
1439 * property does not have the correct numeric format, or if the
1440 * specified name is empty or {@code null}.
1441 *
1442 * @param nm property name.
1443 * @param val default value.
1444 * @return the {@code Long} value of the property.
1445 * @throws SecurityException for the same reasons as
1446 * {@link System#getProperty(String) System.getProperty}
1447 * @see System#getProperty(java.lang.String)
1448 * @see System#getProperty(java.lang.String, java.lang.String)
1449 */
1450 public static Long getLong(String nm, Long val) {
1451 String v = null;
1452 try {
1453 v = System.getProperty(nm);
1454 } catch (IllegalArgumentException | NullPointerException e) {
1455 }
1456 if (v != null) {
1457 try {
1458 return Long.decode(v);
1459 } catch (NumberFormatException e) {
1460 }
1461 }
1462 return val;
1463 }
1464
1465 /**
1466 * Compares two {@code Long} objects numerically.
1467 *
1468 * @param anotherLong the {@code Long} to be compared.
1469 * @return the value {@code 0} if this {@code Long} is
1470 * equal to the argument {@code Long}; a value less than
1471 * {@code 0} if this {@code Long} is numerically less
1472 * than the argument {@code Long}; and a value greater
1473 * than {@code 0} if this {@code Long} is numerically
1474 * greater than the argument {@code Long} (signed
1475 * comparison).
1476 * @since 1.2
1477 */
1478 public int compareTo(Long anotherLong) {
1479 return compare(this.value, anotherLong.value);
1480 }
1481
1482 /**
1483 * Compares two {@code long} values numerically.
1484 * The value returned is identical to what would be returned by:
1485 * <pre>
1486 * Long.valueOf(x).compareTo(Long.valueOf(y))
1487 * </pre>
1488 *
1489 * @param x the first {@code long} to compare
1490 * @param y the second {@code long} to compare
1491 * @return the value {@code 0} if {@code x == y};
1492 * a value less than {@code 0} if {@code x < y}; and
1493 * a value greater than {@code 0} if {@code x > y}
1494 * @since 1.7
1495 */
1496 public static int compare(long x, long y) {
1497 return (x < y) ? -1 : ((x == y) ? 0 : 1);
1498 }
1499
1500 /**
1501 * Compares two {@code long} values numerically treating the values
1502 * as unsigned.
1503 *
1504 * @param x the first {@code long} to compare
1505 * @param y the second {@code long} to compare
1506 * @return the value {@code 0} if {@code x == y}; a value less
1507 * than {@code 0} if {@code x < y} as unsigned values; and
1508 * a value greater than {@code 0} if {@code x > y} as
1509 * unsigned values
1510 * @since 1.8
1511 */
1512 public static int compareUnsigned(long x, long y) {
1513 return compare(x + MIN_VALUE, y + MIN_VALUE);
1514 }
1515
1516
1517 /**
1518 * Returns the unsigned quotient of dividing the first argument by
1519 * the second where each argument and the result is interpreted as
1520 * an unsigned value.
1521 *
1522 * <p>Note that in two's complement arithmetic, the three other
1523 * basic arithmetic operations of add, subtract, and multiply are
1524 * bit-wise identical if the two operands are regarded as both
1525 * being signed or both being unsigned. Therefore separate {@code
1526 * addUnsigned}, etc. methods are not provided.
1527 *
1528 * @param dividend the value to be divided
1529 * @param divisor the value doing the dividing
1530 * @return the unsigned quotient of the first argument divided by
1531 * the second argument
1532 * @see #remainderUnsigned
1533 * @since 1.8
1534 */
1535 public static long divideUnsigned(long dividend, long divisor) {
1536 if (divisor < 0L) { // signed comparison
1537 // Answer must be 0 or 1 depending on relative magnitude
1538 // of dividend and divisor.
1539 return (compareUnsigned(dividend, divisor)) < 0 ? 0L :1L;
1540 }
1541
1542 if (dividend > 0) // Both inputs non-negative
1543 return dividend/divisor;
1544 else {
1545 /*
1546 * For simple code, leveraging BigInteger. Longer and faster
1547 * code written directly in terms of operations on longs is
1548 * possible; see "Hacker's Delight" for divide and remainder
1549 * algorithms.
1550 */
1551 return toUnsignedBigInteger(dividend).
1552 divide(toUnsignedBigInteger(divisor)).longValue();
1553 }
1554 }
1555
1556 /**
1557 * Returns the unsigned remainder from dividing the first argument
1558 * by the second where each argument and the result is interpreted
1559 * as an unsigned value.
1560 *
1561 * @param dividend the value to be divided
1562 * @param divisor the value doing the dividing
1563 * @return the unsigned remainder of the first argument divided by
1564 * the second argument
1565 * @see #divideUnsigned
1566 * @since 1.8
1567 */
1568 public static long remainderUnsigned(long dividend, long divisor) {
1569 if (dividend > 0 && divisor > 0) { // signed comparisons
1570 return dividend % divisor;
1571 } else {
1572 if (compareUnsigned(dividend, divisor) < 0) // Avoid explicit check for 0 divisor
1573 return dividend;
1574 else
1575 return toUnsignedBigInteger(dividend).
1576 remainder(toUnsignedBigInteger(divisor)).longValue();
1577 }
1578 }
1579
1580 // Bit Twiddling
1581
1582 /**
1583 * The number of bits used to represent a {@code long} value in two's
1584 * complement binary form.
1585 *
1586 * @since 1.5
1587 */
1588 @Native public static final int SIZE = 64;
1589
1590 /**
1591 * The number of bytes used to represent a {@code long} value in two's
1592 * complement binary form.
1593 *
1594 * @since 1.8
1595 */
1596 public static final int BYTES = SIZE / Byte.SIZE;
1597
1598 /**
1599 * Returns a {@code long} value with at most a single one-bit, in the
1600 * position of the highest-order ("leftmost") one-bit in the specified
1601 * {@code long} value. Returns zero if the specified value has no
1602 * one-bits in its two's complement binary representation, that is, if it
1603 * is equal to zero.
1604 *
1605 * @param i the value whose highest one bit is to be computed
1606 * @return a {@code long} value with a single one-bit, in the position
1607 * of the highest-order one-bit in the specified value, or zero if
1608 * the specified value is itself equal to zero.
1609 * @since 1.5
1610 */
1611 public static long highestOneBit(long i) {
1612 // HD, Figure 3-1
1613 i |= (i >> 1);
1614 i |= (i >> 2);
1615 i |= (i >> 4);
1616 i |= (i >> 8);
1617 i |= (i >> 16);
1618 i |= (i >> 32);
1619 return i - (i >>> 1);
1620 }
1621
1622 /**
1623 * Returns a {@code long} value with at most a single one-bit, in the
1624 * position of the lowest-order ("rightmost") one-bit in the specified
1625 * {@code long} value. Returns zero if the specified value has no
1626 * one-bits in its two's complement binary representation, that is, if it
1627 * is equal to zero.
1628 *
1629 * @param i the value whose lowest one bit is to be computed
1630 * @return a {@code long} value with a single one-bit, in the position
1631 * of the lowest-order one-bit in the specified value, or zero if
1632 * the specified value is itself equal to zero.
1633 * @since 1.5
1634 */
1635 public static long lowestOneBit(long i) {
1636 // HD, Section 2-1
1637 return i & -i;
1638 }
1639
1640 /**
1641 * Returns the number of zero bits preceding the highest-order
1642 * ("leftmost") one-bit in the two's complement binary representation
1643 * of the specified {@code long} value. Returns 64 if the
1644 * specified value has no one-bits in its two's complement representation,
1645 * in other words if it is equal to zero.
1646 *
1647 * <p>Note that this method is closely related to the logarithm base 2.
1648 * For all positive {@code long} values x:
1649 * <ul>
1650 * <li>floor(log<sub>2</sub>(x)) = {@code 63 - numberOfLeadingZeros(x)}
1651 * <li>ceil(log<sub>2</sub>(x)) = {@code 64 - numberOfLeadingZeros(x - 1)}
1652 * </ul>
1653 *
1654 * @param i the value whose number of leading zeros is to be computed
1655 * @return the number of zero bits preceding the highest-order
1656 * ("leftmost") one-bit in the two's complement binary representation
1657 * of the specified {@code long} value, or 64 if the value
1658 * is equal to zero.
1659 * @since 1.5
1660 */
1661 @HotSpotIntrinsicCandidate
1662 public static int numberOfLeadingZeros(long i) {
1663 // HD, Figure 5-6
1664 if (i == 0)
1665 return 64;
1666 int n = 1;
1667 int x = (int)(i >>> 32);
1668 if (x == 0) { n += 32; x = (int)i; }
1669 if (x >>> 16 == 0) { n += 16; x <<= 16; }
1670 if (x >>> 24 == 0) { n += 8; x <<= 8; }
1671 if (x >>> 28 == 0) { n += 4; x <<= 4; }
1672 if (x >>> 30 == 0) { n += 2; x <<= 2; }
1673 n -= x >>> 31;
1674 return n;
1675 }
1676
1677 /**
1678 * Returns the number of zero bits following the lowest-order ("rightmost")
1679 * one-bit in the two's complement binary representation of the specified
1680 * {@code long} value. Returns 64 if the specified value has no
1681 * one-bits in its two's complement representation, in other words if it is
1682 * equal to zero.
1683 *
1684 * @param i the value whose number of trailing zeros is to be computed
1685 * @return the number of zero bits following the lowest-order ("rightmost")
1686 * one-bit in the two's complement binary representation of the
1687 * specified {@code long} value, or 64 if the value is equal
1688 * to zero.
1689 * @since 1.5
1690 */
1691 @HotSpotIntrinsicCandidate
1692 public static int numberOfTrailingZeros(long i) {
1693 // HD, Figure 5-14
1694 int x, y;
1695 if (i == 0) return 64;
1696 int n = 63;
1697 y = (int)i; if (y != 0) { n = n -32; x = y; } else x = (int)(i>>>32);
1698 y = x <<16; if (y != 0) { n = n -16; x = y; }
1699 y = x << 8; if (y != 0) { n = n - 8; x = y; }
1700 y = x << 4; if (y != 0) { n = n - 4; x = y; }
1701 y = x << 2; if (y != 0) { n = n - 2; x = y; }
1702 return n - ((x << 1) >>> 31);
1703 }
1704
1705 /**
1706 * Returns the number of one-bits in the two's complement binary
1707 * representation of the specified {@code long} value. This function is
1708 * sometimes referred to as the <i>population count</i>.
1709 *
1710 * @param i the value whose bits are to be counted
1711 * @return the number of one-bits in the two's complement binary
1712 * representation of the specified {@code long} value.
1713 * @since 1.5
1714 */
1715 @HotSpotIntrinsicCandidate
1716 public static int bitCount(long i) {
1717 // HD, Figure 5-2
1718 i = i - ((i >>> 1) & 0x5555555555555555L);
1719 i = (i & 0x3333333333333333L) + ((i >>> 2) & 0x3333333333333333L);
1720 i = (i + (i >>> 4)) & 0x0f0f0f0f0f0f0f0fL;
1721 i = i + (i >>> 8);
1722 i = i + (i >>> 16);
1723 i = i + (i >>> 32);
1724 return (int)i & 0x7f;
1725 }
1726
1727 /**
1728 * Returns the value obtained by rotating the two's complement binary
1729 * representation of the specified {@code long} value left by the
1730 * specified number of bits. (Bits shifted out of the left hand, or
1731 * high-order, side reenter on the right, or low-order.)
1732 *
1733 * <p>Note that left rotation with a negative distance is equivalent to
1734 * right rotation: {@code rotateLeft(val, -distance) == rotateRight(val,
1735 * distance)}. Note also that rotation by any multiple of 64 is a
1736 * no-op, so all but the last six bits of the rotation distance can be
1737 * ignored, even if the distance is negative: {@code rotateLeft(val,
1738 * distance) == rotateLeft(val, distance & 0x3F)}.
1739 *
1740 * @param i the value whose bits are to be rotated left
1741 * @param distance the number of bit positions to rotate left
1742 * @return the value obtained by rotating the two's complement binary
1743 * representation of the specified {@code long} value left by the
1744 * specified number of bits.
1745 * @since 1.5
1746 */
1747 public static long rotateLeft(long i, int distance) {
1748 return (i << distance) | (i >>> -distance);
1749 }
1750
1751 /**
1752 * Returns the value obtained by rotating the two's complement binary
1753 * representation of the specified {@code long} value right by the
1754 * specified number of bits. (Bits shifted out of the right hand, or
1755 * low-order, side reenter on the left, or high-order.)
1756 *
1757 * <p>Note that right rotation with a negative distance is equivalent to
1758 * left rotation: {@code rotateRight(val, -distance) == rotateLeft(val,
1759 * distance)}. Note also that rotation by any multiple of 64 is a
1760 * no-op, so all but the last six bits of the rotation distance can be
1761 * ignored, even if the distance is negative: {@code rotateRight(val,
1762 * distance) == rotateRight(val, distance & 0x3F)}.
1763 *
1764 * @param i the value whose bits are to be rotated right
1765 * @param distance the number of bit positions to rotate right
1766 * @return the value obtained by rotating the two's complement binary
1767 * representation of the specified {@code long} value right by the
1768 * specified number of bits.
1769 * @since 1.5
1770 */
1771 public static long rotateRight(long i, int distance) {
1772 return (i >>> distance) | (i << -distance);
1773 }
1774
1775 /**
1776 * Returns the value obtained by reversing the order of the bits in the
1777 * two's complement binary representation of the specified {@code long}
1778 * value.
1779 *
1780 * @param i the value to be reversed
1781 * @return the value obtained by reversing order of the bits in the
1782 * specified {@code long} value.
1783 * @since 1.5
1784 */
1785 public static long reverse(long i) {
1786 // HD, Figure 7-1
1787 i = (i & 0x5555555555555555L) << 1 | (i >>> 1) & 0x5555555555555555L;
1788 i = (i & 0x3333333333333333L) << 2 | (i >>> 2) & 0x3333333333333333L;
1789 i = (i & 0x0f0f0f0f0f0f0f0fL) << 4 | (i >>> 4) & 0x0f0f0f0f0f0f0f0fL;
1790 i = (i & 0x00ff00ff00ff00ffL) << 8 | (i >>> 8) & 0x00ff00ff00ff00ffL;
1791 i = (i << 48) | ((i & 0xffff0000L) << 16) |
1792 ((i >>> 16) & 0xffff0000L) | (i >>> 48);
1793 return i;
1794 }
1795
1796 /**
1797 * Returns the signum function of the specified {@code long} value. (The
1798 * return value is -1 if the specified value is negative; 0 if the
1799 * specified value is zero; and 1 if the specified value is positive.)
1800 *
1801 * @param i the value whose signum is to be computed
1802 * @return the signum function of the specified {@code long} value.
1803 * @since 1.5
1804 */
1805 public static int signum(long i) {
1806 // HD, Section 2-7
1807 return (int) ((i >> 63) | (-i >>> 63));
1808 }
1809
1810 /**
1811 * Returns the value obtained by reversing the order of the bytes in the
1812 * two's complement representation of the specified {@code long} value.
1813 *
1814 * @param i the value whose bytes are to be reversed
1815 * @return the value obtained by reversing the bytes in the specified
1816 * {@code long} value.
1817 * @since 1.5
1818 */
1819 @HotSpotIntrinsicCandidate
1820 public static long reverseBytes(long i) {
1821 i = (i & 0x00ff00ff00ff00ffL) << 8 | (i >>> 8) & 0x00ff00ff00ff00ffL;
1822 return (i << 48) | ((i & 0xffff0000L) << 16) |
1823 ((i >>> 16) & 0xffff0000L) | (i >>> 48);
1824 }
1825
1826 /**
1827 * Adds two {@code long} values together as per the + operator.
1828 *
1829 * @param a the first operand
1830 * @param b the second operand
1831 * @return the sum of {@code a} and {@code b}
1832 * @see java.util.function.BinaryOperator
1833 * @since 1.8
1834 */
1835 public static long sum(long a, long b) {
1836 return a + b;
1837 }
1838
1839 /**
1840 * Returns the greater of two {@code long} values
1841 * as if by calling {@link Math#max(long, long) Math.max}.
1842 *
1843 * @param a the first operand
1844 * @param b the second operand
1845 * @return the greater of {@code a} and {@code b}
1846 * @see java.util.function.BinaryOperator
1847 * @since 1.8
1848 */
1849 public static long max(long a, long b) {
1850 return Math.max(a, b);
1851 }
1852
1853 /**
1854 * Returns the smaller of two {@code long} values
1855 * as if by calling {@link Math#min(long, long) Math.min}.
1856 *
1857 * @param a the first operand
1858 * @param b the second operand
1859 * @return the smaller of {@code a} and {@code b}
1860 * @see java.util.function.BinaryOperator
1861 * @since 1.8
1862 */
1863 public static long min(long a, long b) {
1864 return Math.min(a, b);
1865 }
1866
1867 /** use serialVersionUID from JDK 1.0.2 for interoperability */
1868 @Native private static final long serialVersionUID = 4290774380558885855L;
1869 }