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
31
32 /**
33 * The {@code Long} class wraps a value of the primitive type {@code
34 * long} in an object. An object of type {@code Long} contains a
35 * single field whose type is {@code long}.
36 *
37 * <p> In addition, this class provides several methods for converting
38 * a {@code long} to a {@code String} and a {@code String} to a {@code
39 * long}, as well as other constants and methods useful when dealing
40 * with a {@code long}.
41 *
42 * <p>Implementation note: The implementations of the "bit twiddling"
43 * methods (such as {@link #highestOneBit(long) highestOneBit} and
44 * {@link #numberOfTrailingZeros(long) numberOfTrailingZeros}) are
45 * based on material from Henry S. Warren, Jr.'s <i>Hacker's
46 * Delight</i>, (Addison Wesley, 2002).
47 *
48 * @author Lee Boynton
49 * @author Arthur van Hoff
50 * @author Josh Bloch
51 * @author Joseph D. Darcy
52 * @since JDK1.0
53 */
54 public final class Long extends Number implements Comparable<Long> {
55 /**
56 * A constant holding the minimum value a {@code long} can
57 * have, -2<sup>63</sup>.
58 */
59 @Native public static final long MIN_VALUE = 0x8000000000000000L;
60
61 /**
62 * A constant holding the maximum value a {@code long} can
63 * have, 2<sup>63</sup>-1.
64 */
65 @Native public static final long MAX_VALUE = 0x7fffffffffffffffL;
66
67 /**
68 * The {@code Class} instance representing the primitive type
69 * {@code long}.
70 *
71 * @since JDK1.1
72 */
73 @SuppressWarnings("unchecked")
74 public static final Class<Long> TYPE = (Class<Long>) Class.getPrimitiveClass("long");
75
76 /**
77 * Returns a string representation of the first argument in the
78 * radix specified by the second argument.
79 *
80 * <p>If the radix is smaller than {@code Character.MIN_RADIX}
81 * or larger than {@code Character.MAX_RADIX}, then the radix
82 * {@code 10} is used instead.
83 *
84 * <p>If the first argument is negative, the first element of the
85 * result is the ASCII minus sign {@code '-'}
86 * ({@code '\u005Cu002d'}). If the first argument is not
87 * negative, no sign character appears in the result.
88 *
89 * <p>The remaining characters of the result represent the magnitude
90 * of the first argument. If the magnitude is zero, it is
91 * represented by a single zero character {@code '0'}
92 * ({@code '\u005Cu0030'}); otherwise, the first character of
93 * the representation of the magnitude will not be the zero
94 * character. The following ASCII characters are used as digits:
95 *
96 * <blockquote>
97 * {@code 0123456789abcdefghijklmnopqrstuvwxyz}
98 * </blockquote>
99 *
100 * These are {@code '\u005Cu0030'} through
101 * {@code '\u005Cu0039'} and {@code '\u005Cu0061'} through
102 * {@code '\u005Cu007a'}. If {@code radix} is
103 * <var>N</var>, then the first <var>N</var> of these characters
104 * are used as radix-<var>N</var> digits in the order shown. Thus,
105 * the digits for hexadecimal (radix 16) are
106 * {@code 0123456789abcdef}. If uppercase letters are
107 * desired, the {@link java.lang.String#toUpperCase()} method may
108 * be called on the result:
109 *
110 * <blockquote>
111 * {@code Long.toString(n, 16).toUpperCase()}
112 * </blockquote>
113 *
114 * @param i a {@code long} to be converted to a string.
115 * @param radix the radix to use in the string representation.
116 * @return a string representation of the argument in the specified radix.
117 * @see java.lang.Character#MAX_RADIX
118 * @see java.lang.Character#MIN_RADIX
119 */
120 public static String toString(long i, int radix) {
121 if (radix < Character.MIN_RADIX || radix > Character.MAX_RADIX)
122 radix = 10;
123 if (radix == 10)
124 return toString(i);
125 char[] buf = new char[65];
126 int charPos = 64;
127 boolean negative = (i < 0);
128
129 if (!negative) {
130 i = -i;
131 }
132
133 while (i <= -radix) {
134 buf[charPos--] = Integer.digits[(int)(-(i % radix))];
135 i = i / radix;
136 }
137 buf[charPos] = Integer.digits[(int)(-i)];
138
139 if (negative) {
140 buf[--charPos] = '-';
141 }
142
143 return new String(buf, charPos, (65 - charPos));
144 }
145
146 /**
147 * Returns a string representation of the first argument as an
148 * unsigned integer value in the radix specified by the second
149 * argument.
150 *
151 * <p>If the radix is smaller than {@code Character.MIN_RADIX}
152 * or larger than {@code Character.MAX_RADIX}, then the radix
153 * {@code 10} is used instead.
154 *
155 * <p>Note that since the first argument is treated as an unsigned
156 * value, no leading sign character is printed.
157 *
158 * <p>If the magnitude is zero, it is represented by a single zero
159 * character {@code '0'} ({@code '\u005Cu0030'}); otherwise,
160 * the first character of the representation of the magnitude will
161 * not be the zero character.
162 *
163 * <p>The behavior of radixes and the characters used as digits
164 * are the same as {@link #toString(long, int) toString}.
165 *
166 * @param i an integer to be converted to an unsigned string.
167 * @param radix the radix to use in the string representation.
168 * @return an unsigned string representation of the argument in the specified radix.
169 * @see #toString(long, int)
170 * @since 1.8
171 */
172 public static String toUnsignedString(long i, int radix) {
173 if (i >= 0)
174 return toString(i, radix);
175 else {
176 switch (radix) {
177 case 2:
178 return toBinaryString(i);
179
180 case 4:
181 return toUnsignedString0(i, 2);
182
183 case 8:
184 return toOctalString(i);
185
186 case 10:
187 /*
188 * We can get the effect of an unsigned division by 10
189 * on a long value by first shifting right, yielding a
190 * positive value, and then dividing by 5. This
191 * allows the last digit and preceding digits to be
192 * isolated more quickly than by an initial conversion
193 * to BigInteger.
194 */
195 long quot = (i >>> 1) / 5;
196 long rem = i - quot * 10;
197 return toString(quot) + rem;
198
199 case 16:
200 return toHexString(i);
201
202 case 32:
203 return toUnsignedString0(i, 5);
204
205 default:
206 return toUnsignedBigInteger(i).toString(radix);
207 }
208 }
209 }
210
211 /**
212 * Return a BigInteger equal to the unsigned value of the
213 * argument.
214 */
215 private static BigInteger toUnsignedBigInteger(long i) {
216 if (i >= 0L)
217 return BigInteger.valueOf(i);
218 else {
219 int upper = (int) (i >>> 32);
220 int lower = (int) i;
221
222 // return (upper << 32) + lower
223 return (BigInteger.valueOf(Integer.toUnsignedLong(upper))).shiftLeft(32).
224 add(BigInteger.valueOf(Integer.toUnsignedLong(lower)));
225 }
226 }
227
228 /**
229 * Returns a string representation of the {@code long}
230 * argument as an unsigned integer in base 16.
231 *
232 * <p>The unsigned {@code long} value is the argument plus
233 * 2<sup>64</sup> if the argument is negative; otherwise, it is
234 * equal to the argument. This value is converted to a string of
235 * ASCII digits in hexadecimal (base 16) with no extra
236 * leading {@code 0}s.
237 *
238 * <p>The value of the argument can be recovered from the returned
239 * string {@code s} by calling {@link
240 * Long#parseUnsignedLong(String, int) Long.parseUnsignedLong(s,
241 * 16)}.
242 *
243 * <p>If the unsigned magnitude is zero, it is represented by a
244 * single zero character {@code '0'} ({@code '\u005Cu0030'});
245 * otherwise, the first character of the representation of the
246 * unsigned magnitude will not be the zero character. The
247 * following characters are used as hexadecimal digits:
248 *
249 * <blockquote>
250 * {@code 0123456789abcdef}
251 * </blockquote>
252 *
253 * These are the characters {@code '\u005Cu0030'} through
254 * {@code '\u005Cu0039'} and {@code '\u005Cu0061'} through
255 * {@code '\u005Cu0066'}. If uppercase letters are desired,
256 * the {@link java.lang.String#toUpperCase()} method may be called
257 * on the result:
258 *
259 * <blockquote>
260 * {@code Long.toHexString(n).toUpperCase()}
261 * </blockquote>
262 *
263 * @param i a {@code long} to be converted to a string.
264 * @return the string representation of the unsigned {@code long}
265 * value represented by the argument in hexadecimal
266 * (base 16).
267 * @see #parseUnsignedLong(String, int)
268 * @see #toUnsignedString(long, int)
269 * @since JDK 1.0.2
270 */
271 public static String toHexString(long i) {
272 return toUnsignedString0(i, 4);
273 }
274
275 /**
276 * Returns a string representation of the {@code long}
277 * argument as an unsigned integer in base 8.
278 *
279 * <p>The unsigned {@code long} value is the argument plus
280 * 2<sup>64</sup> if the argument is negative; otherwise, it is
281 * equal to the argument. This value is converted to a string of
282 * ASCII digits in octal (base 8) with no extra leading
283 * {@code 0}s.
284 *
285 * <p>The value of the argument can be recovered from the returned
286 * string {@code s} by calling {@link
287 * Long#parseUnsignedLong(String, int) Long.parseUnsignedLong(s,
288 * 8)}.
289 *
290 * <p>If the unsigned magnitude is zero, it is represented by a
291 * single zero character {@code '0'} ({@code '\u005Cu0030'});
292 * otherwise, the first character of the representation of the
293 * unsigned magnitude will not be the zero character. The
294 * following characters are used as octal digits:
295 *
296 * <blockquote>
297 * {@code 01234567}
298 * </blockquote>
299 *
300 * These are the characters {@code '\u005Cu0030'} through
301 * {@code '\u005Cu0037'}.
302 *
303 * @param i a {@code long} to be converted to a string.
304 * @return the string representation of the unsigned {@code long}
305 * value represented by the argument in octal (base 8).
306 * @see #parseUnsignedLong(String, int)
307 * @see #toUnsignedString(long, int)
308 * @since JDK 1.0.2
309 */
310 public static String toOctalString(long i) {
311 return toUnsignedString0(i, 3);
312 }
313
314 /**
315 * Returns a string representation of the {@code long}
316 * argument as an unsigned integer in base 2.
317 *
318 * <p>The unsigned {@code long} value is the argument plus
319 * 2<sup>64</sup> if the argument is negative; otherwise, it is
320 * equal to the argument. This value is converted to a string of
321 * ASCII digits in binary (base 2) with no extra leading
322 * {@code 0}s.
323 *
324 * <p>The value of the argument can be recovered from the returned
325 * string {@code s} by calling {@link
326 * Long#parseUnsignedLong(String, int) Long.parseUnsignedLong(s,
327 * 2)}.
328 *
329 * <p>If the unsigned magnitude is zero, it is represented by a
330 * single zero character {@code '0'} ({@code '\u005Cu0030'});
331 * otherwise, the first character of the representation of the
332 * unsigned magnitude will not be the zero character. The
333 * characters {@code '0'} ({@code '\u005Cu0030'}) and {@code
334 * '1'} ({@code '\u005Cu0031'}) are used as binary digits.
335 *
336 * @param i a {@code long} to be converted to a string.
337 * @return the string representation of the unsigned {@code long}
338 * value represented by the argument in binary (base 2).
339 * @see #parseUnsignedLong(String, int)
340 * @see #toUnsignedString(long, int)
341 * @since JDK 1.0.2
342 */
343 public static String toBinaryString(long i) {
344 return toUnsignedString0(i, 1);
345 }
346
347 /**
348 * Format a long (treated as unsigned) into a String.
349 * @param val the value to format
350 * @param shift the log2 of the base to format in (4 for hex, 3 for octal, 1 for binary)
351 */
352 static String toUnsignedString0(long val, int shift) {
353 // assert shift > 0 && shift <=5 : "Illegal shift value";
354 int mag = Long.SIZE - Long.numberOfLeadingZeros(val);
355 int chars = Math.max(((mag + (shift - 1)) / shift), 1);
356 char[] buf = new char[chars];
357
358 formatUnsignedLong(val, shift, buf, 0, chars);
359 return new String(buf, true);
360 }
361
362 /**
363 * Format a long (treated as unsigned) into a character buffer.
364 * @param val the unsigned long to format
365 * @param shift the log2 of the base to format in (4 for hex, 3 for octal, 1 for binary)
366 * @param buf the character buffer to write to
367 * @param offset the offset in the destination buffer to start at
368 * @param len the number of characters to write
369 * @return the lowest character location used
370 */
371 static int formatUnsignedLong(long val, int shift, char[] buf, int offset, int len) {
372 int charPos = len;
373 int radix = 1 << shift;
374 int mask = radix - 1;
375 do {
376 buf[offset + --charPos] = Integer.digits[((int) val) & mask];
377 val >>>= shift;
378 } while (val != 0 && charPos > 0);
379
380 return charPos;
381 }
382
383 /**
384 * Returns a {@code String} object representing the specified
385 * {@code long}. The argument is converted to signed decimal
386 * representation and returned as a string, exactly as if the
387 * argument and the radix 10 were given as arguments to the {@link
388 * #toString(long, int)} method.
389 *
390 * @param i a {@code long} to be converted.
391 * @return a string representation of the argument in base 10.
392 */
393 public static String toString(long i) {
394 if (i == Long.MIN_VALUE)
395 return "-9223372036854775808";
396 int size = (i < 0) ? stringSize(-i) + 1 : stringSize(i);
397 char[] buf = new char[size];
398 getChars(i, size, buf);
399 return new String(buf, true);
400 }
401
402 /**
403 * Returns a string representation of the argument as an unsigned
404 * decimal value.
405 *
406 * The argument is converted to unsigned decimal representation
407 * and returned as a string exactly as if the argument and radix
408 * 10 were given as arguments to the {@link #toUnsignedString(long,
409 * int)} method.
410 *
411 * @param i an integer to be converted to an unsigned string.
412 * @return an unsigned string representation of the argument.
413 * @see #toUnsignedString(long, int)
414 * @since 1.8
415 */
416 public static String toUnsignedString(long i) {
417 return toUnsignedString(i, 10);
418 }
419
420 /**
421 * Places characters representing the integer i into the
422 * character array buf. The characters are placed into
423 * the buffer backwards starting with the least significant
424 * digit at the specified index (exclusive), and working
425 * backwards from there.
426 *
427 * Will fail if i == Long.MIN_VALUE
428 */
429 static void getChars(long i, int index, char[] buf) {
430 long q;
431 int r;
432 int charPos = index;
433 char sign = 0;
434
435 if (i < 0) {
436 sign = '-';
437 i = -i;
438 }
439
440 // Get 2 digits/iteration using longs until quotient fits into an int
441 while (i > Integer.MAX_VALUE) {
442 q = i / 100;
443 // really: r = i - (q * 100);
444 r = (int)(i - ((q << 6) + (q << 5) + (q << 2)));
445 i = q;
446 buf[--charPos] = Integer.DigitOnes[r];
447 buf[--charPos] = Integer.DigitTens[r];
448 }
449
450 // Get 2 digits/iteration using ints
451 int q2;
452 int i2 = (int)i;
453 while (i2 >= 65536) {
454 q2 = i2 / 100;
455 // really: r = i2 - (q * 100);
456 r = i2 - ((q2 << 6) + (q2 << 5) + (q2 << 2));
457 i2 = q2;
458 buf[--charPos] = Integer.DigitOnes[r];
459 buf[--charPos] = Integer.DigitTens[r];
460 }
461
462 // Fall thru to fast mode for smaller numbers
463 // assert(i2 <= 65536, i2);
464 for (;;) {
465 q2 = (i2 * 52429) >>> (16+3);
466 r = i2 - ((q2 << 3) + (q2 << 1)); // r = i2-(q2*10) ...
467 buf[--charPos] = Integer.digits[r];
468 i2 = q2;
469 if (i2 == 0) break;
470 }
471 if (sign != 0) {
472 buf[--charPos] = sign;
473 }
474 }
475
476 // Requires positive x
477 static int stringSize(long x) {
478 long p = 10;
479 for (int i=1; i<19; i++) {
480 if (x < p)
481 return i;
482 p = 10*p;
483 }
484 return 19;
485 }
486
487 /**
488 * Parses the string argument as a signed {@code long} in the
489 * radix specified by the second argument. The characters in the
490 * string must all be digits of the specified radix (as determined
491 * by whether {@link java.lang.Character#digit(char, int)} returns
492 * a nonnegative value), except that the first character may be an
493 * ASCII minus sign {@code '-'} ({@code '\u005Cu002D'}) to
494 * indicate a negative value or an ASCII plus sign {@code '+'}
495 * ({@code '\u005Cu002B'}) to indicate a positive value. The
496 * resulting {@code long} value is returned.
497 *
498 * <p>Note that neither the character {@code L}
499 * ({@code '\u005Cu004C'}) nor {@code l}
500 * ({@code '\u005Cu006C'}) is permitted to appear at the end
501 * of the string as a type indicator, as would be permitted in
502 * Java programming language source code - except that either
503 * {@code L} or {@code l} may appear as a digit for a
504 * radix greater than or equal to 22.
505 *
506 * <p>An exception of type {@code NumberFormatException} is
507 * thrown if any of the following situations occurs:
508 * <ul>
509 *
510 * <li>The first argument is {@code null} or is a string of
511 * length zero.
512 *
513 * <li>The {@code radix} is either smaller than {@link
514 * java.lang.Character#MIN_RADIX} or larger than {@link
515 * java.lang.Character#MAX_RADIX}.
516 *
517 * <li>Any character of the string is not a digit of the specified
518 * radix, except that the first character may be a minus sign
519 * {@code '-'} ({@code '\u005Cu002d'}) or plus sign {@code
520 * '+'} ({@code '\u005Cu002B'}) provided that the string is
521 * longer than length 1.
522 *
523 * <li>The value represented by the string is not a value of type
524 * {@code long}.
525 * </ul>
526 *
527 * <p>Examples:
528 * <blockquote><pre>
529 * parseLong("0", 10) returns 0L
530 * parseLong("473", 10) returns 473L
531 * parseLong("+42", 10) returns 42L
532 * parseLong("-0", 10) returns 0L
533 * parseLong("-FF", 16) returns -255L
534 * parseLong("1100110", 2) returns 102L
535 * parseLong("99", 8) throws a NumberFormatException
536 * parseLong("Hazelnut", 10) throws a NumberFormatException
537 * parseLong("Hazelnut", 36) returns 1356099454469L
538 * </pre></blockquote>
539 *
540 * @param s the {@code String} containing the
541 * {@code long} representation to be parsed.
542 * @param radix the radix to be used while parsing {@code s}.
543 * @return the {@code long} represented by the string argument in
544 * the specified radix.
545 * @throws NumberFormatException if the string does not contain a
546 * parsable {@code long}.
547 */
548 public static long parseLong(String s, int radix)
549 throws NumberFormatException
550 {
551 if (s == null) {
552 throw new NumberFormatException("null");
553 }
554
555 if (radix < Character.MIN_RADIX) {
556 throw new NumberFormatException("radix " + radix +
557 " less than Character.MIN_RADIX");
558 }
559 if (radix > Character.MAX_RADIX) {
560 throw new NumberFormatException("radix " + radix +
561 " greater than Character.MAX_RADIX");
562 }
563
564 long result = 0;
565 boolean negative = false;
566 int i = 0, len = s.length();
567 long limit = -Long.MAX_VALUE;
568 long multmin;
569 int digit;
570
571 if (len > 0) {
572 char firstChar = s.charAt(0);
573 if (firstChar < '0') { // Possible leading "+" or "-"
574 if (firstChar == '-') {
575 negative = true;
576 limit = Long.MIN_VALUE;
577 } else if (firstChar != '+')
578 throw NumberFormatException.forInputString(s);
579
580 if (len == 1) // Cannot have lone "+" or "-"
581 throw NumberFormatException.forInputString(s);
582 i++;
583 }
584 multmin = limit / radix;
585 while (i < len) {
586 // Accumulating negatively avoids surprises near MAX_VALUE
587 digit = Character.digit(s.charAt(i++),radix);
588 if (digit < 0) {
589 throw NumberFormatException.forInputString(s);
590 }
591 if (result < multmin) {
592 throw NumberFormatException.forInputString(s);
593 }
594 result *= radix;
595 if (result < limit + digit) {
596 throw NumberFormatException.forInputString(s);
597 }
598 result -= digit;
599 }
600 } else {
601 throw NumberFormatException.forInputString(s);
602 }
603 return negative ? result : -result;
604 }
605
606 /**
607 * Parses the string argument as a signed decimal {@code long}.
608 * The characters in the string must all be decimal digits, except
609 * that the first character may be an ASCII minus sign {@code '-'}
610 * ({@code \u005Cu002D'}) to indicate a negative value or an
611 * ASCII plus sign {@code '+'} ({@code '\u005Cu002B'}) to
612 * indicate a positive value. The resulting {@code long} value is
613 * returned, exactly as if the argument and the radix {@code 10}
614 * were given as arguments to the {@link
615 * #parseLong(java.lang.String, int)} method.
616 *
617 * <p>Note that neither the character {@code L}
618 * ({@code '\u005Cu004C'}) nor {@code l}
619 * ({@code '\u005Cu006C'}) is permitted to appear at the end
620 * of the string as a type indicator, as would be permitted in
621 * Java programming language source code.
622 *
623 * @param s a {@code String} containing the {@code long}
624 * representation to be parsed
625 * @return the {@code long} represented by the argument in
626 * decimal.
627 * @throws NumberFormatException if the string does not contain a
628 * parsable {@code long}.
629 */
630 public static long parseLong(String s) throws NumberFormatException {
631 return parseLong(s, 10);
632 }
633
634 /**
635 * Parses the string argument as an unsigned {@code long} in the
636 * radix specified by the second argument. An unsigned integer
637 * maps the values usually associated with negative numbers to
638 * positive numbers larger than {@code MAX_VALUE}.
639 *
640 * The characters in the string must all be digits of the
641 * specified radix (as determined by whether {@link
642 * java.lang.Character#digit(char, int)} returns a nonnegative
643 * value), except that the first character may be an ASCII plus
644 * sign {@code '+'} ({@code '\u005Cu002B'}). The resulting
645 * integer value is returned.
646 *
647 * <p>An exception of type {@code NumberFormatException} is
648 * thrown if any of the following situations occurs:
649 * <ul>
650 * <li>The first argument is {@code null} or is a string of
651 * length zero.
652 *
653 * <li>The radix is either smaller than
654 * {@link java.lang.Character#MIN_RADIX} or
655 * larger than {@link java.lang.Character#MAX_RADIX}.
656 *
657 * <li>Any character of the string is not a digit of the specified
658 * radix, except that the first character may be a plus sign
659 * {@code '+'} ({@code '\u005Cu002B'}) provided that the
660 * string is longer than length 1.
661 *
662 * <li>The value represented by the string is larger than the
663 * largest unsigned {@code long}, 2<sup>64</sup>-1.
664 *
665 * </ul>
666 *
667 *
668 * @param s the {@code String} containing the unsigned integer
669 * representation to be parsed
670 * @param radix the radix to be used while parsing {@code s}.
671 * @return the unsigned {@code long} represented by the string
672 * argument in the specified radix.
673 * @throws NumberFormatException if the {@code String}
674 * does not contain a parsable {@code long}.
675 * @since 1.8
676 */
677 public static long parseUnsignedLong(String s, int radix)
678 throws NumberFormatException {
679 if (s == null) {
680 throw new NumberFormatException("null");
681 }
682
683 int len = s.length();
684 if (len > 0) {
685 char firstChar = s.charAt(0);
686 if (firstChar == '-') {
687 throw new
688 NumberFormatException(String.format("Illegal leading minus sign " +
689 "on unsigned string %s.", s));
690 } else {
691 if (len <= 12 || // Long.MAX_VALUE in Character.MAX_RADIX is 13 digits
692 (radix == 10 && len <= 18) ) { // Long.MAX_VALUE in base 10 is 19 digits
693 return parseLong(s, radix);
694 }
695
696 // No need for range checks on len due to testing above.
697 long first = parseLong(s.substring(0, len - 1), radix);
698 int second = Character.digit(s.charAt(len - 1), radix);
699 if (second < 0) {
700 throw new NumberFormatException("Bad digit at end of " + s);
701 }
702 long result = first * radix + second;
703
704 /*
705 * Test leftmost bits of multiprecision extension of first*radix
706 * for overflow. The number of bits needed is defined by
707 * GUARD_BIT = ceil(log2(Character.MAX_RADIX)) + 1 = 7. Then
708 * int guard = radix*(int)(first >>> (64 - GUARD_BIT)) and
709 * overflow is tested by splitting guard in the ranges
710 * guard < 92, 92 <= guard < 128, and 128 <= guard, where
711 * 92 = 128 - Character.MAX_RADIX. Note that guard cannot take
712 * on a value which does not include a prime factor in the legal
713 * radix range.
714 */
715 int guard = radix * (int) (first >>> 57);
716 if (guard >= 128 ||
717 (result >= 0 && guard >= 128 - Character.MAX_RADIX)) {
718 /*
719 * For purposes of exposition, the programmatic statements
720 * below should be taken to be multi-precision, i.e., not
721 * subject to overflow.
722 *
723 * A) Condition guard >= 128:
724 * If guard >= 128 then first*radix >= 2^7 * 2^57 = 2^64
725 * hence always overflow.
726 *
727 * B) Condition guard < 92:
728 * Define left7 = first >>> 57.
729 * Given first = (left7 * 2^57) + (first & (2^57 - 1)) then
730 * result <= (radix*left7)*2^57 + radix*(2^57 - 1) + second.
731 * Thus if radix*left7 < 92, radix <= 36, and second < 36,
732 * then result < 92*2^57 + 36*(2^57 - 1) + 36 = 2^64 hence
733 * never overflow.
734 *
735 * C) Condition 92 <= guard < 128:
736 * first*radix + second >= radix*left7*2^57 + second
737 * so that first*radix + second >= 92*2^57 + 0 > 2^63
738 *
739 * D) Condition guard < 128:
740 * radix*first <= (radix*left7) * 2^57 + radix*(2^57 - 1)
741 * so
742 * radix*first + second <= (radix*left7) * 2^57 + radix*(2^57 - 1) + 36
743 * thus
744 * radix*first + second < 128 * 2^57 + 36*2^57 - radix + 36
745 * whence
746 * radix*first + second < 2^64 + 2^6*2^57 = 2^64 + 2^63
747 *
748 * E) Conditions C, D, and result >= 0:
749 * C and D combined imply the mathematical result
750 * 2^63 < first*radix + second < 2^64 + 2^63. The lower
751 * bound is therefore negative as a signed long, but the
752 * upper bound is too small to overflow again after the
753 * signed long overflows to positive above 2^64 - 1. Hence
754 * result >= 0 implies overflow given C and D.
755 */
756 throw new NumberFormatException(String.format("String value %s exceeds " +
757 "range of unsigned long.", s));
758 }
759 return result;
760 }
761 } else {
762 throw NumberFormatException.forInputString(s);
763 }
764 }
765
766 /**
767 * Parses the string argument as an unsigned decimal {@code long}. The
768 * characters in the string must all be decimal digits, except
769 * that the first character may be an an ASCII plus sign {@code
770 * '+'} ({@code '\u005Cu002B'}). The resulting integer value
771 * is returned, exactly as if the argument and the radix 10 were
772 * given as arguments to the {@link
773 * #parseUnsignedLong(java.lang.String, int)} method.
774 *
775 * @param s a {@code String} containing the unsigned {@code long}
776 * representation to be parsed
777 * @return the unsigned {@code long} value represented by the decimal string argument
778 * @throws NumberFormatException if the string does not contain a
779 * parsable unsigned integer.
780 * @since 1.8
781 */
782 public static long parseUnsignedLong(String s) throws NumberFormatException {
783 return parseUnsignedLong(s, 10);
784 }
785
786 /**
787 * Returns a {@code Long} object holding the value
788 * extracted from the specified {@code String} when parsed
789 * with the radix given by the second argument. The first
790 * argument is interpreted as representing a signed
791 * {@code long} in the radix specified by the second
792 * argument, exactly as if the arguments were given to the {@link
793 * #parseLong(java.lang.String, int)} method. The result is a
794 * {@code Long} object that represents the {@code long}
795 * value specified by the string.
796 *
797 * <p>In other words, this method returns a {@code Long} object equal
798 * to the value of:
799 *
800 * <blockquote>
801 * {@code new Long(Long.parseLong(s, radix))}
802 * </blockquote>
803 *
804 * @param s the string to be parsed
805 * @param radix the radix to be used in interpreting {@code s}
806 * @return a {@code Long} object holding the value
807 * represented by the string argument in the specified
808 * radix.
809 * @throws NumberFormatException If the {@code String} does not
810 * contain a parsable {@code long}.
811 */
812 public static Long valueOf(String s, int radix) throws NumberFormatException {
813 return Long.valueOf(parseLong(s, radix));
814 }
815
816 /**
817 * Returns a {@code Long} object holding the value
818 * of the specified {@code String}. The argument is
819 * interpreted as representing a signed decimal {@code long},
820 * exactly as if the argument were given to the {@link
821 * #parseLong(java.lang.String)} method. The result is a
822 * {@code Long} object that represents the integer value
823 * specified by the string.
824 *
825 * <p>In other words, this method returns a {@code Long} object
826 * equal to the value of:
827 *
828 * <blockquote>
829 * {@code new Long(Long.parseLong(s))}
830 * </blockquote>
831 *
832 * @param s the string to be parsed.
833 * @return a {@code Long} object holding the value
834 * represented by the string argument.
835 * @throws NumberFormatException If the string cannot be parsed
836 * as a {@code long}.
837 */
838 public static Long valueOf(String s) throws NumberFormatException
839 {
840 return Long.valueOf(parseLong(s, 10));
841 }
842
843 private static class LongCache {
844 private LongCache(){}
845
846 static final Long cache[] = new Long[-(-128) + 127 + 1];
847
848 static {
849 for(int i = 0; i < cache.length; i++)
850 cache[i] = new Long(i - 128);
851 }
852 }
853
854 /**
855 * Returns a {@code Long} instance representing the specified
856 * {@code long} value.
857 * If a new {@code Long} instance is not required, this method
858 * should generally be used in preference to the constructor
859 * {@link #Long(long)}, as this method is likely to yield
860 * significantly better space and time performance by caching
861 * frequently requested values.
862 *
863 * Note that unlike the {@linkplain Integer#valueOf(int)
864 * corresponding method} in the {@code Integer} class, this method
865 * is <em>not</em> required to cache values within a particular
866 * range.
867 *
868 * @param l a long value.
869 * @return a {@code Long} instance representing {@code l}.
870 * @since 1.5
871 */
872 public static Long valueOf(long l) {
873 final int offset = 128;
874 if (l >= -128 && l <= 127) { // will cache
875 return LongCache.cache[(int)l + offset];
876 }
877 return new Long(l);
878 }
879
880 /**
881 * Decodes a {@code String} into a {@code Long}.
882 * Accepts decimal, hexadecimal, and octal numbers given by the
883 * following grammar:
884 *
885 * <blockquote>
886 * <dl>
887 * <dt><i>DecodableString:</i>
888 * <dd><i>Sign<sub>opt</sub> DecimalNumeral</i>
889 * <dd><i>Sign<sub>opt</sub></i> {@code 0x} <i>HexDigits</i>
890 * <dd><i>Sign<sub>opt</sub></i> {@code 0X} <i>HexDigits</i>
891 * <dd><i>Sign<sub>opt</sub></i> {@code #} <i>HexDigits</i>
892 * <dd><i>Sign<sub>opt</sub></i> {@code 0} <i>OctalDigits</i>
893 *
894 * <dt><i>Sign:</i>
895 * <dd>{@code -}
896 * <dd>{@code +}
897 * </dl>
898 * </blockquote>
899 *
900 * <i>DecimalNumeral</i>, <i>HexDigits</i>, and <i>OctalDigits</i>
901 * are as defined in section 3.10.1 of
902 * <cite>The Java™ Language Specification</cite>,
903 * except that underscores are not accepted between digits.
904 *
905 * <p>The sequence of characters following an optional
906 * sign and/or radix specifier ("{@code 0x}", "{@code 0X}",
907 * "{@code #}", or leading zero) is parsed as by the {@code
908 * Long.parseLong} method with the indicated radix (10, 16, or 8).
909 * This sequence of characters must represent a positive value or
910 * a {@link NumberFormatException} will be thrown. The result is
911 * negated if first character of the specified {@code String} is
912 * the minus sign. No whitespace characters are permitted in the
913 * {@code String}.
914 *
915 * @param nm the {@code String} to decode.
916 * @return a {@code Long} object holding the {@code long}
917 * value represented by {@code nm}
918 * @throws NumberFormatException if the {@code String} does not
919 * contain a parsable {@code long}.
920 * @see java.lang.Long#parseLong(String, int)
921 * @since 1.2
922 */
923 public static Long decode(String nm) throws NumberFormatException {
924 int radix = 10;
925 int index = 0;
926 boolean negative = false;
927 Long result;
928
929 if (nm.length() == 0)
930 throw new NumberFormatException("Zero length string");
931 char firstChar = nm.charAt(0);
932 // Handle sign, if present
933 if (firstChar == '-') {
934 negative = true;
935 index++;
936 } else if (firstChar == '+')
937 index++;
938
939 // Handle radix specifier, if present
940 if (nm.startsWith("0x", index) || nm.startsWith("0X", index)) {
941 index += 2;
942 radix = 16;
943 }
944 else if (nm.startsWith("#", index)) {
945 index ++;
946 radix = 16;
947 }
948 else if (nm.startsWith("0", index) && nm.length() > 1 + index) {
949 index ++;
950 radix = 8;
951 }
952
953 if (nm.startsWith("-", index) || nm.startsWith("+", index))
954 throw new NumberFormatException("Sign character in wrong position");
955
956 try {
957 result = Long.valueOf(nm.substring(index), radix);
958 result = negative ? Long.valueOf(-result.longValue()) : result;
959 } catch (NumberFormatException e) {
960 // If number is Long.MIN_VALUE, we'll end up here. The next line
961 // handles this case, and causes any genuine format error to be
962 // rethrown.
963 String constant = negative ? ("-" + nm.substring(index))
964 : nm.substring(index);
965 result = Long.valueOf(constant, radix);
966 }
967 return result;
968 }
969
970 /**
971 * The value of the {@code Long}.
972 *
973 * @serial
974 */
975 private final long value;
976
977 /**
978 * Constructs a newly allocated {@code Long} object that
979 * represents the specified {@code long} argument.
980 *
981 * @param value the value to be represented by the
982 * {@code Long} object.
983 */
984 public Long(long value) {
985 this.value = value;
986 }
987
988 /**
989 * Constructs a newly allocated {@code Long} object that
990 * represents the {@code long} value indicated by the
991 * {@code String} parameter. The string is converted to a
992 * {@code long} value in exactly the manner used by the
993 * {@code parseLong} method for radix 10.
994 *
995 * @param s the {@code String} to be converted to a
996 * {@code Long}.
997 * @throws NumberFormatException if the {@code String} does not
998 * contain a parsable {@code long}.
999 * @see java.lang.Long#parseLong(java.lang.String, int)
1000 */
1001 public Long(String s) throws NumberFormatException {
1002 this.value = parseLong(s, 10);
1003 }
1004
1005 /**
1006 * Returns the value of this {@code Long} as a {@code byte} after
1007 * a narrowing primitive conversion.
1008 * @jls 5.1.3 Narrowing Primitive Conversions
1009 */
1010 public byte byteValue() {
1011 return (byte)value;
1012 }
1013
1014 /**
1015 * Returns the value of this {@code Long} as a {@code short} after
1016 * a narrowing primitive conversion.
1017 * @jls 5.1.3 Narrowing Primitive Conversions
1018 */
1019 public short shortValue() {
1020 return (short)value;
1021 }
1022
1023 /**
1024 * Returns the value of this {@code Long} as an {@code int} after
1025 * a narrowing primitive conversion.
1026 * @jls 5.1.3 Narrowing Primitive Conversions
1027 */
1028 public int intValue() {
1029 return (int)value;
1030 }
1031
1032 /**
1033 * Returns the value of this {@code Long} as a
1034 * {@code long} value.
1035 */
1036 public long longValue() {
1037 return value;
1038 }
1039
1040 /**
1041 * Returns the value of this {@code Long} as a {@code float} after
1042 * a widening primitive conversion.
1043 * @jls 5.1.2 Widening Primitive Conversions
1044 */
1045 public float floatValue() {
1046 return (float)value;
1047 }
1048
1049 /**
1050 * Returns the value of this {@code Long} as a {@code double}
1051 * after a widening primitive conversion.
1052 * @jls 5.1.2 Widening Primitive Conversions
1053 */
1054 public double doubleValue() {
1055 return (double)value;
1056 }
1057
1058 /**
1059 * Returns a {@code String} object representing this
1060 * {@code Long}'s value. The value is converted to signed
1061 * decimal representation and returned as a string, exactly as if
1062 * the {@code long} value were given as an argument to the
1063 * {@link java.lang.Long#toString(long)} method.
1064 *
1065 * @return a string representation of the value of this object in
1066 * base 10.
1067 */
1068 public String toString() {
1069 return toString(value);
1070 }
1071
1072 /**
1073 * Returns a hash code for this {@code Long}. The result is
1074 * the exclusive OR of the two halves of the primitive
1075 * {@code long} value held by this {@code Long}
1076 * object. That is, the hashcode is the value of the expression:
1077 *
1078 * <blockquote>
1079 * {@code (int)(this.longValue()^(this.longValue()>>>32))}
1080 * </blockquote>
1081 *
1082 * @return a hash code value for this object.
1083 */
1084 @Override
1085 public int hashCode() {
1086 return Long.hashCode(value);
1087 }
1088
1089 /**
1090 * Returns a hash code for a {@code long} value; compatible with
1091 * {@code Long.hashCode()}.
1092 *
1093 * @param value the value to hash
1094 * @return a hash code value for a {@code long} value.
1095 * @since 1.8
1096 */
1097 public static int hashCode(long value) {
1098 return (int)(value ^ (value >>> 32));
1099 }
1100
1101 /**
1102 * Compares this object to the specified object. The result is
1103 * {@code true} if and only if the argument is not
1104 * {@code null} and is a {@code Long} object that
1105 * contains the same {@code long} value as this object.
1106 *
1107 * @param obj the object to compare with.
1108 * @return {@code true} if the objects are the same;
1109 * {@code false} otherwise.
1110 */
1111 public boolean equals(Object obj) {
1112 if (obj instanceof Long) {
1113 return value == ((Long)obj).longValue();
1114 }
1115 return false;
1116 }
1117
1118 /**
1119 * Determines the {@code long} value of the system property
1120 * with the specified name.
1121 *
1122 * <p>The first argument is treated as the name of a system
1123 * property. System properties are accessible through the {@link
1124 * java.lang.System#getProperty(java.lang.String)} method. The
1125 * string value of this property is then interpreted as a {@code
1126 * long} value using the grammar supported by {@link Long#decode decode}
1127 * and a {@code Long} object representing this value is returned.
1128 *
1129 * <p>If there is no property with the specified name, if the
1130 * specified name is empty or {@code null}, or if the property
1131 * does not have the correct numeric format, then {@code null} is
1132 * returned.
1133 *
1134 * <p>In other words, this method returns a {@code Long} object
1135 * equal to the value of:
1136 *
1137 * <blockquote>
1138 * {@code getLong(nm, null)}
1139 * </blockquote>
1140 *
1141 * @param nm property name.
1142 * @return the {@code Long} value of the property.
1143 * @throws SecurityException for the same reasons as
1144 * {@link System#getProperty(String) System.getProperty}
1145 * @see java.lang.System#getProperty(java.lang.String)
1146 * @see java.lang.System#getProperty(java.lang.String, java.lang.String)
1147 */
1148 public static Long getLong(String nm) {
1149 return getLong(nm, null);
1150 }
1151
1152 /**
1153 * Determines the {@code long} value of the system property
1154 * with the specified name.
1155 *
1156 * <p>The first argument is treated as the name of a system
1157 * property. System properties are accessible through the {@link
1158 * java.lang.System#getProperty(java.lang.String)} method. The
1159 * string value of this property is then interpreted as a {@code
1160 * long} value using the grammar supported by {@link Long#decode decode}
1161 * and a {@code Long} object representing this value is returned.
1162 *
1163 * <p>The second argument is the default value. A {@code Long} object
1164 * that represents the value of the second argument is returned if there
1165 * is no property of the specified name, if the property does not have
1166 * the correct numeric format, or if the specified name is empty or null.
1167 *
1168 * <p>In other words, this method returns a {@code Long} object equal
1169 * to the value of:
1170 *
1171 * <blockquote>
1172 * {@code getLong(nm, new Long(val))}
1173 * </blockquote>
1174 *
1175 * but in practice it may be implemented in a manner such as:
1176 *
1177 * <blockquote><pre>
1178 * Long result = getLong(nm, null);
1179 * return (result == null) ? new Long(val) : result;
1180 * </pre></blockquote>
1181 *
1182 * to avoid the unnecessary allocation of a {@code Long} object when
1183 * the default value is not needed.
1184 *
1185 * @param nm property name.
1186 * @param val default value.
1187 * @return the {@code Long} value of the property.
1188 * @throws SecurityException for the same reasons as
1189 * {@link System#getProperty(String) System.getProperty}
1190 * @see java.lang.System#getProperty(java.lang.String)
1191 * @see java.lang.System#getProperty(java.lang.String, java.lang.String)
1192 */
1193 public static Long getLong(String nm, long val) {
1194 Long result = Long.getLong(nm, null);
1195 return (result == null) ? Long.valueOf(val) : result;
1196 }
1197
1198 /**
1199 * Returns the {@code long} value of the system property with
1200 * the specified name. The first argument is treated as the name
1201 * of a system property. System properties are accessible through
1202 * the {@link java.lang.System#getProperty(java.lang.String)}
1203 * method. The string value of this property is then interpreted
1204 * as a {@code long} value, as per the
1205 * {@link Long#decode decode} method, and a {@code Long} object
1206 * representing this value is returned; in summary:
1207 *
1208 * <ul>
1209 * <li>If the property value begins with the two ASCII characters
1210 * {@code 0x} or the ASCII character {@code #}, not followed by
1211 * a minus sign, then the rest of it is parsed as a hexadecimal integer
1212 * exactly as for the method {@link #valueOf(java.lang.String, int)}
1213 * with radix 16.
1214 * <li>If the property value begins with the ASCII character
1215 * {@code 0} followed by another character, it is parsed as
1216 * an octal integer exactly as by the method {@link
1217 * #valueOf(java.lang.String, int)} with radix 8.
1218 * <li>Otherwise the property value is parsed as a decimal
1219 * integer exactly as by the method
1220 * {@link #valueOf(java.lang.String, int)} with radix 10.
1221 * </ul>
1222 *
1223 * <p>Note that, in every case, neither {@code L}
1224 * ({@code '\u005Cu004C'}) nor {@code l}
1225 * ({@code '\u005Cu006C'}) is permitted to appear at the end
1226 * of the property value as a type indicator, as would be
1227 * permitted in Java programming language source code.
1228 *
1229 * <p>The second argument is the default value. The default value is
1230 * returned if there is no property of the specified name, if the
1231 * property does not have the correct numeric format, or if the
1232 * specified name is empty or {@code null}.
1233 *
1234 * @param nm property name.
1235 * @param val default value.
1236 * @return the {@code Long} value of the property.
1237 * @throws SecurityException for the same reasons as
1238 * {@link System#getProperty(String) System.getProperty}
1239 * @see System#getProperty(java.lang.String)
1240 * @see System#getProperty(java.lang.String, java.lang.String)
1241 */
1242 public static Long getLong(String nm, Long val) {
1243 String v = null;
1244 try {
1245 v = System.getProperty(nm);
1246 } catch (IllegalArgumentException | NullPointerException e) {
1247 }
1248 if (v != null) {
1249 try {
1250 return Long.decode(v);
1251 } catch (NumberFormatException e) {
1252 }
1253 }
1254 return val;
1255 }
1256
1257 /**
1258 * Compares two {@code Long} objects numerically.
1259 *
1260 * @param anotherLong the {@code Long} to be compared.
1261 * @return the value {@code 0} if this {@code Long} is
1262 * equal to the argument {@code Long}; a value less than
1263 * {@code 0} if this {@code Long} is numerically less
1264 * than the argument {@code Long}; and a value greater
1265 * than {@code 0} if this {@code Long} is numerically
1266 * greater than the argument {@code Long} (signed
1267 * comparison).
1268 * @since 1.2
1269 */
1270 public int compareTo(Long anotherLong) {
1271 return compare(this.value, anotherLong.value);
1272 }
1273
1274 /**
1275 * Compares two {@code long} values numerically.
1276 * The value returned is identical to what would be returned by:
1277 * <pre>
1278 * Long.valueOf(x).compareTo(Long.valueOf(y))
1279 * </pre>
1280 *
1281 * @param x the first {@code long} to compare
1282 * @param y the second {@code long} to compare
1283 * @return the value {@code 0} if {@code x == y};
1284 * a value less than {@code 0} if {@code x < y}; and
1285 * a value greater than {@code 0} if {@code x > y}
1286 * @since 1.7
1287 */
1288 public static int compare(long x, long y) {
1289 return (x < y) ? -1 : ((x == y) ? 0 : 1);
1290 }
1291
1292 /**
1293 * Compares two {@code long} values numerically treating the values
1294 * as unsigned.
1295 *
1296 * @param x the first {@code long} to compare
1297 * @param y the second {@code long} to compare
1298 * @return the value {@code 0} if {@code x == y}; a value less
1299 * than {@code 0} if {@code x < y} as unsigned values; and
1300 * a value greater than {@code 0} if {@code x > y} as
1301 * unsigned values
1302 * @since 1.8
1303 */
1304 public static int compareUnsigned(long x, long y) {
1305 return compare(x + MIN_VALUE, y + MIN_VALUE);
1306 }
1307
1308
1309 /**
1310 * Returns the unsigned quotient of dividing the first argument by
1311 * the second where each argument and the result is interpreted as
1312 * an unsigned value.
1313 *
1314 * <p>Note that in two's complement arithmetic, the three other
1315 * basic arithmetic operations of add, subtract, and multiply are
1316 * bit-wise identical if the two operands are regarded as both
1317 * being signed or both being unsigned. Therefore separate {@code
1318 * addUnsigned}, etc. methods are not provided.
1319 *
1320 * @param dividend the value to be divided
1321 * @param divisor the value doing the dividing
1322 * @return the unsigned quotient of the first argument divided by
1323 * the second argument
1324 * @see #remainderUnsigned
1325 * @since 1.8
1326 */
1327 public static long divideUnsigned(long dividend, long divisor) {
1328 if (divisor < 0L) { // signed comparison
1329 // Answer must be 0 or 1 depending on relative magnitude
1330 // of dividend and divisor.
1331 return (compareUnsigned(dividend, divisor)) < 0 ? 0L :1L;
1332 }
1333
1334 if (dividend > 0) // Both inputs non-negative
1335 return dividend/divisor;
1336 else {
1337 /*
1338 * For simple code, leveraging BigInteger. Longer and faster
1339 * code written directly in terms of operations on longs is
1340 * possible; see "Hacker's Delight" for divide and remainder
1341 * algorithms.
1342 */
1343 return toUnsignedBigInteger(dividend).
1344 divide(toUnsignedBigInteger(divisor)).longValue();
1345 }
1346 }
1347
1348 /**
1349 * Returns the unsigned remainder from dividing the first argument
1350 * by the second where each argument and the result is interpreted
1351 * as an unsigned value.
1352 *
1353 * @param dividend the value to be divided
1354 * @param divisor the value doing the dividing
1355 * @return the unsigned remainder of the first argument divided by
1356 * the second argument
1357 * @see #divideUnsigned
1358 * @since 1.8
1359 */
1360 public static long remainderUnsigned(long dividend, long divisor) {
1361 if (dividend > 0 && divisor > 0) { // signed comparisons
1362 return dividend % divisor;
1363 } else {
1364 if (compareUnsigned(dividend, divisor) < 0) // Avoid explicit check for 0 divisor
1365 return dividend;
1366 else
1367 return toUnsignedBigInteger(dividend).
1368 remainder(toUnsignedBigInteger(divisor)).longValue();
1369 }
1370 }
1371
1372 // Bit Twiddling
1373
1374 /**
1375 * The number of bits used to represent a {@code long} value in two's
1376 * complement binary form.
1377 *
1378 * @since 1.5
1379 */
1380 @Native public static final int SIZE = 64;
1381
1382 /**
1383 * The number of bytes used to represent a {@code long} value in two's
1384 * complement binary form.
1385 *
1386 * @since 1.8
1387 */
1388 public static final int BYTES = SIZE / Byte.SIZE;
1389
1390 /**
1391 * Returns a {@code long} value with at most a single one-bit, in the
1392 * position of the highest-order ("leftmost") one-bit in the specified
1393 * {@code long} value. Returns zero if the specified value has no
1394 * one-bits in its two's complement binary representation, that is, if it
1395 * is equal to zero.
1396 *
1397 * @param i the value whose highest one bit is to be computed
1398 * @return a {@code long} value with a single one-bit, in the position
1399 * of the highest-order one-bit in the specified value, or zero if
1400 * the specified value is itself equal to zero.
1401 * @since 1.5
1402 */
1403 public static long highestOneBit(long i) {
1404 // HD, Figure 3-1
1405 i |= (i >> 1);
1406 i |= (i >> 2);
1407 i |= (i >> 4);
1408 i |= (i >> 8);
1409 i |= (i >> 16);
1410 i |= (i >> 32);
1411 return i - (i >>> 1);
1412 }
1413
1414 /**
1415 * Returns a {@code long} value with at most a single one-bit, in the
1416 * position of the lowest-order ("rightmost") one-bit in the specified
1417 * {@code long} value. Returns zero if the specified value has no
1418 * one-bits in its two's complement binary representation, that is, if it
1419 * is equal to zero.
1420 *
1421 * @param i the value whose lowest one bit is to be computed
1422 * @return a {@code long} value with a single one-bit, in the position
1423 * of the lowest-order one-bit in the specified value, or zero if
1424 * the specified value is itself equal to zero.
1425 * @since 1.5
1426 */
1427 public static long lowestOneBit(long i) {
1428 // HD, Section 2-1
1429 return i & -i;
1430 }
1431
1432 /**
1433 * Returns the number of zero bits preceding the highest-order
1434 * ("leftmost") one-bit in the two's complement binary representation
1435 * of the specified {@code long} value. Returns 64 if the
1436 * specified value has no one-bits in its two's complement representation,
1437 * in other words if it is equal to zero.
1438 *
1439 * <p>Note that this method is closely related to the logarithm base 2.
1440 * For all positive {@code long} values x:
1441 * <ul>
1442 * <li>floor(log<sub>2</sub>(x)) = {@code 63 - numberOfLeadingZeros(x)}
1443 * <li>ceil(log<sub>2</sub>(x)) = {@code 64 - numberOfLeadingZeros(x - 1)}
1444 * </ul>
1445 *
1446 * @param i the value whose number of leading zeros is to be computed
1447 * @return the number of zero bits preceding the highest-order
1448 * ("leftmost") one-bit in the two's complement binary representation
1449 * of the specified {@code long} value, or 64 if the value
1450 * is equal to zero.
1451 * @since 1.5
1452 */
1453 public static int numberOfLeadingZeros(long i) {
1454 // HD, Figure 5-6
1455 if (i == 0)
1456 return 64;
1457 int n = 1;
1458 int x = (int)(i >>> 32);
1459 if (x == 0) { n += 32; x = (int)i; }
1460 if (x >>> 16 == 0) { n += 16; x <<= 16; }
1461 if (x >>> 24 == 0) { n += 8; x <<= 8; }
1462 if (x >>> 28 == 0) { n += 4; x <<= 4; }
1463 if (x >>> 30 == 0) { n += 2; x <<= 2; }
1464 n -= x >>> 31;
1465 return n;
1466 }
1467
1468 /**
1469 * Returns the number of zero bits following the lowest-order ("rightmost")
1470 * one-bit in the two's complement binary representation of the specified
1471 * {@code long} value. Returns 64 if the specified value has no
1472 * one-bits in its two's complement representation, in other words if it is
1473 * equal to zero.
1474 *
1475 * @param i the value whose number of trailing zeros is to be computed
1476 * @return the number of zero bits following the lowest-order ("rightmost")
1477 * one-bit in the two's complement binary representation of the
1478 * specified {@code long} value, or 64 if the value is equal
1479 * to zero.
1480 * @since 1.5
1481 */
1482 public static int numberOfTrailingZeros(long i) {
1483 // HD, Figure 5-14
1484 int x, y;
1485 if (i == 0) return 64;
1486 int n = 63;
1487 y = (int)i; if (y != 0) { n = n -32; x = y; } else x = (int)(i>>>32);
1488 y = x <<16; if (y != 0) { n = n -16; x = y; }
1489 y = x << 8; if (y != 0) { n = n - 8; x = y; }
1490 y = x << 4; if (y != 0) { n = n - 4; x = y; }
1491 y = x << 2; if (y != 0) { n = n - 2; x = y; }
1492 return n - ((x << 1) >>> 31);
1493 }
1494
1495 /**
1496 * Returns the number of one-bits in the two's complement binary
1497 * representation of the specified {@code long} value. This function is
1498 * sometimes referred to as the <i>population count</i>.
1499 *
1500 * @param i the value whose bits are to be counted
1501 * @return the number of one-bits in the two's complement binary
1502 * representation of the specified {@code long} value.
1503 * @since 1.5
1504 */
1505 public static int bitCount(long i) {
1506 // HD, Figure 5-14
1507 i = i - ((i >>> 1) & 0x5555555555555555L);
1508 i = (i & 0x3333333333333333L) + ((i >>> 2) & 0x3333333333333333L);
1509 i = (i + (i >>> 4)) & 0x0f0f0f0f0f0f0f0fL;
1510 i = i + (i >>> 8);
1511 i = i + (i >>> 16);
1512 i = i + (i >>> 32);
1513 return (int)i & 0x7f;
1514 }
1515
1516 /**
1517 * Returns the value obtained by rotating the two's complement binary
1518 * representation of the specified {@code long} value left by the
1519 * specified number of bits. (Bits shifted out of the left hand, or
1520 * high-order, side reenter on the right, or low-order.)
1521 *
1522 * <p>Note that left rotation with a negative distance is equivalent to
1523 * right rotation: {@code rotateLeft(val, -distance) == rotateRight(val,
1524 * distance)}. Note also that rotation by any multiple of 64 is a
1525 * no-op, so all but the last six bits of the rotation distance can be
1526 * ignored, even if the distance is negative: {@code rotateLeft(val,
1527 * distance) == rotateLeft(val, distance & 0x3F)}.
1528 *
1529 * @param i the value whose bits are to be rotated left
1530 * @param distance the number of bit positions to rotate left
1531 * @return the value obtained by rotating the two's complement binary
1532 * representation of the specified {@code long} value left by the
1533 * specified number of bits.
1534 * @since 1.5
1535 */
1536 public static long rotateLeft(long i, int distance) {
1537 return (i << distance) | (i >>> -distance);
1538 }
1539
1540 /**
1541 * Returns the value obtained by rotating the two's complement binary
1542 * representation of the specified {@code long} value right by the
1543 * specified number of bits. (Bits shifted out of the right hand, or
1544 * low-order, side reenter on the left, or high-order.)
1545 *
1546 * <p>Note that right rotation with a negative distance is equivalent to
1547 * left rotation: {@code rotateRight(val, -distance) == rotateLeft(val,
1548 * distance)}. Note also that rotation by any multiple of 64 is a
1549 * no-op, so all but the last six bits of the rotation distance can be
1550 * ignored, even if the distance is negative: {@code rotateRight(val,
1551 * distance) == rotateRight(val, distance & 0x3F)}.
1552 *
1553 * @param i the value whose bits are to be rotated right
1554 * @param distance the number of bit positions to rotate right
1555 * @return the value obtained by rotating the two's complement binary
1556 * representation of the specified {@code long} value right by the
1557 * specified number of bits.
1558 * @since 1.5
1559 */
1560 public static long rotateRight(long i, int distance) {
1561 return (i >>> distance) | (i << -distance);
1562 }
1563
1564 /**
1565 * Returns the value obtained by reversing the order of the bits in the
1566 * two's complement binary representation of the specified {@code long}
1567 * value.
1568 *
1569 * @param i the value to be reversed
1570 * @return the value obtained by reversing order of the bits in the
1571 * specified {@code long} value.
1572 * @since 1.5
1573 */
1574 public static long reverse(long i) {
1575 // HD, Figure 7-1
1576 i = (i & 0x5555555555555555L) << 1 | (i >>> 1) & 0x5555555555555555L;
1577 i = (i & 0x3333333333333333L) << 2 | (i >>> 2) & 0x3333333333333333L;
1578 i = (i & 0x0f0f0f0f0f0f0f0fL) << 4 | (i >>> 4) & 0x0f0f0f0f0f0f0f0fL;
1579 i = (i & 0x00ff00ff00ff00ffL) << 8 | (i >>> 8) & 0x00ff00ff00ff00ffL;
1580 i = (i << 48) | ((i & 0xffff0000L) << 16) |
1581 ((i >>> 16) & 0xffff0000L) | (i >>> 48);
1582 return i;
1583 }
1584
1585 /**
1586 * Returns the signum function of the specified {@code long} value. (The
1587 * return value is -1 if the specified value is negative; 0 if the
1588 * specified value is zero; and 1 if the specified value is positive.)
1589 *
1590 * @param i the value whose signum is to be computed
1591 * @return the signum function of the specified {@code long} value.
1592 * @since 1.5
1593 */
1594 public static int signum(long i) {
1595 // HD, Section 2-7
1596 return (int) ((i >> 63) | (-i >>> 63));
1597 }
1598
1599 /**
1600 * Returns the value obtained by reversing the order of the bytes in the
1601 * two's complement representation of the specified {@code long} value.
1602 *
1603 * @param i the value whose bytes are to be reversed
1604 * @return the value obtained by reversing the bytes in the specified
1605 * {@code long} value.
1606 * @since 1.5
1607 */
1608 public static long reverseBytes(long i) {
1609 i = (i & 0x00ff00ff00ff00ffL) << 8 | (i >>> 8) & 0x00ff00ff00ff00ffL;
1610 return (i << 48) | ((i & 0xffff0000L) << 16) |
1611 ((i >>> 16) & 0xffff0000L) | (i >>> 48);
1612 }
1613
1614 /**
1615 * Adds two {@code long} values together as per the + operator.
1616 *
1617 * @param a the first operand
1618 * @param b the second operand
1619 * @return the sum of {@code a} and {@code b}
1620 * @see java.util.function.BinaryOperator
1621 * @since 1.8
1622 */
1623 public static long sum(long a, long b) {
1624 return a + b;
1625 }
1626
1627 /**
1628 * Returns the greater of two {@code long} values
1629 * as if by calling {@link Math#max(long, long) Math.max}.
1630 *
1631 * @param a the first operand
1632 * @param b the second operand
1633 * @return the greater of {@code a} and {@code b}
1634 * @see java.util.function.BinaryOperator
1635 * @since 1.8
1636 */
1637 public static long max(long a, long b) {
1638 return Math.max(a, b);
1639 }
1640
1641 /**
1642 * Returns the smaller of two {@code long} values
1643 * as if by calling {@link Math#min(long, long) Math.min}.
1644 *
1645 * @param a the first operand
1646 * @param b the second operand
1647 * @return the smaller of {@code a} and {@code b}
1648 * @see java.util.function.BinaryOperator
1649 * @since 1.8
1650 */
1651 public static long min(long a, long b) {
1652 return Math.min(a, b);
1653 }
1654
1655 /** use serialVersionUID from JDK 1.0.2 for interoperability */
1656 @Native private static final long serialVersionUID = 4290774380558885855L;
1657 }