1 /*
2 * Copyright (c) 1994, 2011, 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 /**
29 * The {@code Long} class wraps a value of the primitive type {@code
30 * long} in an object. An object of type {@code Long} contains a
31 * single field whose type is {@code long}.
32 *
33 * <p> In addition, this class provides several methods for converting
34 * a {@code long} to a {@code String} and a {@code String} to a {@code
35 * long}, as well as other constants and methods useful when dealing
36 * with a {@code long}.
37 *
38 * <p>Implementation note: The implementations of the "bit twiddling"
39 * methods (such as {@link #highestOneBit(long) highestOneBit} and
40 * {@link #numberOfTrailingZeros(long) numberOfTrailingZeros}) are
41 * based on material from Henry S. Warren, Jr.'s <i>Hacker's
42 * Delight</i>, (Addison Wesley, 2002).
43 *
44 * @author Lee Boynton
45 * @author Arthur van Hoff
46 * @author Josh Bloch
47 * @author Joseph D. Darcy
48 * @since JDK1.0
49 */
50 public final class Long extends Number implements Comparable<Long> {
51 /**
52 * A constant holding the minimum value a {@code long} can
53 * have, -2<sup>63</sup>.
54 */
55 public static final long MIN_VALUE = 0x8000000000000000L;
56
57 /**
58 * A constant holding the maximum value a {@code long} can
59 * have, 2<sup>63</sup>-1.
60 */
61 public static final long MAX_VALUE = 0x7fffffffffffffffL;
62
63 /**
64 * The {@code Class} instance representing the primitive type
65 * {@code long}.
66 *
67 * @since JDK1.1
68 */
69 @SuppressWarnings("unchecked")
70 public static final Class<Long> TYPE = (Class<Long>) Class.getPrimitiveClass("long");
71
72 /**
73 * Returns a string representation of the first argument in the
74 * radix specified by the second argument.
75 *
76 * <p>If the radix is smaller than {@code Character.MIN_RADIX}
77 * or larger than {@code Character.MAX_RADIX}, then the radix
78 * {@code 10} is used instead.
79 *
80 * <p>If the first argument is negative, the first element of the
81 * result is the ASCII minus sign {@code '-'}
82 * (<code>'\u002d'</code>). If the first argument is not
83 * negative, no sign character appears in the result.
84 *
85 * <p>The remaining characters of the result represent the magnitude
86 * of the first argument. If the magnitude is zero, it is
87 * represented by a single zero character {@code '0'}
88 * (<code>'\u0030'</code>); otherwise, the first character of
89 * the representation of the magnitude will not be the zero
90 * character. The following ASCII characters are used as digits:
91 *
92 * <blockquote>
93 * {@code 0123456789abcdefghijklmnopqrstuvwxyz}
94 * </blockquote>
95 *
96 * These are <code>'\u0030'</code> through
97 * <code>'\u0039'</code> and <code>'\u0061'</code> through
98 * <code>'\u007a'</code>. If {@code radix} is
99 * <var>N</var>, then the first <var>N</var> of these characters
100 * are used as radix-<var>N</var> digits in the order shown. Thus,
101 * the digits for hexadecimal (radix 16) are
102 * {@code 0123456789abcdef}. If uppercase letters are
103 * desired, the {@link java.lang.String#toUpperCase()} method may
104 * be called on the result:
105 *
106 * <blockquote>
107 * {@code Long.toString(n, 16).toUpperCase()}
108 * </blockquote>
109 *
110 * @param i a {@code long} to be converted to a string.
111 * @param radix the radix to use in the string representation.
112 * @return a string representation of the argument in the specified radix.
113 * @see java.lang.Character#MAX_RADIX
114 * @see java.lang.Character#MIN_RADIX
115 */
116 public static String toString(long i, int radix) {
117 if (radix < Character.MIN_RADIX || radix > Character.MAX_RADIX)
118 radix = 10;
119 if (radix == 10)
120 return toString(i);
121 char[] buf = new char[65];
122 int charPos = 64;
123 boolean negative = (i < 0);
124
125 if (!negative) {
126 i = -i;
127 }
128
129 while (i <= -radix) {
130 buf[charPos--] = Integer.digits[(int)(-(i % radix))];
131 i = i / radix;
132 }
133 buf[charPos] = Integer.digits[(int)(-i)];
134
135 if (negative) {
136 buf[--charPos] = '-';
137 }
138
139 return new String(buf, charPos, (65 - charPos));
140 }
141
142 /**
143 * Returns a string representation of the {@code long}
144 * argument as an unsigned integer in base 16.
145 *
146 * <p>The unsigned {@code long} value is the argument plus
147 * 2<sup>64</sup> if the argument is negative; otherwise, it is
148 * equal to the argument. This value is converted to a string of
149 * ASCII digits in hexadecimal (base 16) with no extra
150 * leading {@code 0}s. If the unsigned magnitude is zero, it
151 * is represented by a single zero character {@code '0'}
152 * (<code>'\u0030'</code>); otherwise, the first character of
153 * the representation of the unsigned magnitude will not be the
154 * zero character. The following characters are used as
155 * hexadecimal digits:
156 *
157 * <blockquote>
158 * {@code 0123456789abcdef}
159 * </blockquote>
160 *
161 * These are the characters <code>'\u0030'</code> through
162 * <code>'\u0039'</code> and <code>'\u0061'</code> through
163 * <code>'\u0066'</code>. If uppercase letters are desired,
164 * the {@link java.lang.String#toUpperCase()} method may be called
165 * on the result:
166 *
167 * <blockquote>
168 * {@code Long.toHexString(n).toUpperCase()}
169 * </blockquote>
170 *
171 * @param i a {@code long} to be converted to a string.
172 * @return the string representation of the unsigned {@code long}
173 * value represented by the argument in hexadecimal
174 * (base 16).
175 * @since JDK 1.0.2
176 */
177 public static String toHexString(long i) {
178 return toUnsignedString(i, 4);
179 }
180
181 /**
182 * Returns a string representation of the {@code long}
183 * argument as an unsigned integer in base 8.
184 *
185 * <p>The unsigned {@code long} value is the argument plus
186 * 2<sup>64</sup> if the argument is negative; otherwise, it is
187 * equal to the argument. This value is converted to a string of
188 * ASCII digits in octal (base 8) with no extra leading
189 * {@code 0}s.
190 *
191 * <p>If the unsigned magnitude is zero, it is represented by a
192 * single zero character {@code '0'}
193 * (<code>'\u0030'</code>); otherwise, the first character of
194 * the representation of the unsigned magnitude will not be the
195 * zero character. The following characters are used as octal
196 * digits:
197 *
198 * <blockquote>
199 * {@code 01234567}
200 * </blockquote>
201 *
202 * These are the characters <code>'\u0030'</code> through
203 * <code>'\u0037'</code>.
204 *
205 * @param i a {@code long} to be converted to a string.
206 * @return the string representation of the unsigned {@code long}
207 * value represented by the argument in octal (base 8).
208 * @since JDK 1.0.2
209 */
210 public static String toOctalString(long i) {
211 return toUnsignedString(i, 3);
212 }
213
214 /**
215 * Returns a string representation of the {@code long}
216 * argument as an unsigned integer in base 2.
217 *
218 * <p>The unsigned {@code long} value is the argument plus
219 * 2<sup>64</sup> if the argument is negative; otherwise, it is
220 * equal to the argument. This value is converted to a string of
221 * ASCII digits in binary (base 2) with no extra leading
222 * {@code 0}s. If the unsigned magnitude is zero, it is
223 * represented by a single zero character {@code '0'}
224 * (<code>'\u0030'</code>); otherwise, the first character of
225 * the representation of the unsigned magnitude will not be the
226 * zero character. The characters {@code '0'}
227 * (<code>'\u0030'</code>) and {@code '1'}
228 * (<code>'\u0031'</code>) are used as binary digits.
229 *
230 * @param i a {@code long} to be converted to a string.
231 * @return the string representation of the unsigned {@code long}
232 * value represented by the argument in binary (base 2).
233 * @since JDK 1.0.2
234 */
235 public static String toBinaryString(long i) {
236 return toUnsignedString(i, 1);
237 }
238
239 /**
240 * Convert the integer to an unsigned number.
241 */
242 private static String toUnsignedString(long i, int shift) {
243 char[] buf = new char[64];
244 int charPos = 64;
245 int radix = 1 << shift;
246 long mask = radix - 1;
247 do {
248 buf[--charPos] = Integer.digits[(int)(i & mask)];
249 i >>>= shift;
250 } while (i != 0);
251 return new String(buf, charPos, (64 - charPos));
252 }
253
254 /**
255 * Returns a {@code String} object representing the specified
256 * {@code long}. The argument is converted to signed decimal
257 * representation and returned as a string, exactly as if the
258 * argument and the radix 10 were given as arguments to the {@link
259 * #toString(long, int)} method.
260 *
261 * @param i a {@code long} to be converted.
262 * @return a string representation of the argument in base 10.
263 */
264 public static String toString(long i) {
265 if (i == Long.MIN_VALUE)
266 return "-9223372036854775808";
267 int size = (i < 0) ? stringSize(-i) + 1 : stringSize(i);
268 char[] buf = new char[size];
269 getChars(i, size, buf);
270 return new String(0, size, buf);
271 }
272
273 /**
274 * Places characters representing the integer i into the
275 * character array buf. The characters are placed into
276 * the buffer backwards starting with the least significant
277 * digit at the specified index (exclusive), and working
278 * backwards from there.
279 *
280 * Will fail if i == Long.MIN_VALUE
281 */
282 static void getChars(long i, int index, char[] buf) {
283 long q;
284 int r;
285 int charPos = index;
286 char sign = 0;
287
288 if (i < 0) {
289 sign = '-';
290 i = -i;
291 }
292
293 // Get 2 digits/iteration using longs until quotient fits into an int
294 while (i > Integer.MAX_VALUE) {
295 q = i / 100;
296 // really: r = i - (q * 100);
297 r = (int)(i - ((q << 6) + (q << 5) + (q << 2)));
298 i = q;
299 buf[--charPos] = Integer.DigitOnes[r];
300 buf[--charPos] = Integer.DigitTens[r];
301 }
302
303 // Get 2 digits/iteration using ints
304 int q2;
305 int i2 = (int)i;
306 while (i2 >= 65536) {
307 q2 = i2 / 100;
308 // really: r = i2 - (q * 100);
309 r = i2 - ((q2 << 6) + (q2 << 5) + (q2 << 2));
310 i2 = q2;
311 buf[--charPos] = Integer.DigitOnes[r];
312 buf[--charPos] = Integer.DigitTens[r];
313 }
314
315 // Fall thru to fast mode for smaller numbers
316 // assert(i2 <= 65536, i2);
317 for (;;) {
318 q2 = (i2 * 52429) >>> (16+3);
319 r = i2 - ((q2 << 3) + (q2 << 1)); // r = i2-(q2*10) ...
320 buf[--charPos] = Integer.digits[r];
321 i2 = q2;
322 if (i2 == 0) break;
323 }
324 if (sign != 0) {
325 buf[--charPos] = sign;
326 }
327 }
328
329 // Requires positive x
330 static int stringSize(long x) {
331 long p = 10;
332 for (int i=1; i<19; i++) {
333 if (x < p)
334 return i;
335 p = 10*p;
336 }
337 return 19;
338 }
339
340 /**
341 * Parses the string argument as a signed {@code long} in the
342 * radix specified by the second argument. The characters in the
343 * string must all be digits of the specified radix (as determined
344 * by whether {@link java.lang.Character#digit(char, int)} returns
345 * a nonnegative value), except that the first character may be an
346 * ASCII minus sign {@code '-'} (<code>'\u002D'</code>) to
347 * indicate a negative value or an ASCII plus sign {@code '+'}
348 * (<code>'\u002B'</code>) to indicate a positive value. The
349 * resulting {@code long} value is returned.
350 *
351 * <p>Note that neither the character {@code L}
352 * (<code>'\u004C'</code>) nor {@code l}
353 * (<code>'\u006C'</code>) is permitted to appear at the end
354 * of the string as a type indicator, as would be permitted in
355 * Java programming language source code - except that either
356 * {@code L} or {@code l} may appear as a digit for a
357 * radix greater than 22.
358 *
359 * <p>An exception of type {@code NumberFormatException} is
360 * thrown if any of the following situations occurs:
361 * <ul>
362 *
363 * <li>The first argument is {@code null} or is a string of
364 * length zero.
365 *
366 * <li>The {@code radix} is either smaller than {@link
367 * java.lang.Character#MIN_RADIX} or larger than {@link
368 * java.lang.Character#MAX_RADIX}.
369 *
370 * <li>Any character of the string is not a digit of the specified
371 * radix, except that the first character may be a minus sign
372 * {@code '-'} (<code>'\u002d'</code>) or plus sign {@code
373 * '+'} (<code>'\u002B'</code>) provided that the string is
374 * longer than length 1.
375 *
376 * <li>The value represented by the string is not a value of type
377 * {@code long}.
378 * </ul>
379 *
380 * <p>Examples:
381 * <blockquote><pre>
382 * parseLong("0", 10) returns 0L
383 * parseLong("473", 10) returns 473L
384 * parseLong("+42", 10) returns 42L
385 * parseLong("-0", 10) returns 0L
386 * parseLong("-FF", 16) returns -255L
387 * parseLong("1100110", 2) returns 102L
388 * parseLong("99", 8) throws a NumberFormatException
389 * parseLong("Hazelnut", 10) throws a NumberFormatException
390 * parseLong("Hazelnut", 36) returns 1356099454469L
391 * </pre></blockquote>
392 *
393 * @param s the {@code String} containing the
394 * {@code long} representation to be parsed.
395 * @param radix the radix to be used while parsing {@code s}.
396 * @return the {@code long} represented by the string argument in
397 * the specified radix.
398 * @throws NumberFormatException if the string does not contain a
399 * parsable {@code long}.
400 */
401 public static long parseLong(String s, int radix)
402 throws NumberFormatException
403 {
404 if (s == null) {
405 throw new NumberFormatException("null");
406 }
407
408 if (radix < Character.MIN_RADIX) {
409 throw new NumberFormatException("radix " + radix +
410 " less than Character.MIN_RADIX");
411 }
412 if (radix > Character.MAX_RADIX) {
413 throw new NumberFormatException("radix " + radix +
414 " greater than Character.MAX_RADIX");
415 }
416
417 long result = 0;
418 boolean negative = false;
419 int i = 0, len = s.length();
420 long limit = -Long.MAX_VALUE;
421 long multmin;
422 int digit;
423
424 if (len > 0) {
425 char firstChar = s.charAt(0);
426 if (firstChar < '0') { // Possible leading "+" or "-"
427 if (firstChar == '-') {
428 negative = true;
429 limit = Long.MIN_VALUE;
430 } else if (firstChar != '+')
431 throw NumberFormatException.forInputString(s);
432
433 if (len == 1) // Cannot have lone "+" or "-"
434 throw NumberFormatException.forInputString(s);
435 i++;
436 }
437 multmin = limit / radix;
438 while (i < len) {
439 // Accumulating negatively avoids surprises near MAX_VALUE
440 digit = Character.digit(s.charAt(i++),radix);
441 if (digit < 0) {
442 throw NumberFormatException.forInputString(s);
443 }
444 if (result < multmin) {
445 throw NumberFormatException.forInputString(s);
446 }
447 result *= radix;
448 if (result < limit + digit) {
449 throw NumberFormatException.forInputString(s);
450 }
451 result -= digit;
452 }
453 } else {
454 throw NumberFormatException.forInputString(s);
455 }
456 return negative ? result : -result;
457 }
458
459 /**
460 * Parses the string argument as a signed decimal {@code long}.
461 * The characters in the string must all be decimal digits, except
462 * that the first character may be an ASCII minus sign {@code '-'}
463 * (<code>\u002D'</code>) to indicate a negative value or an
464 * ASCII plus sign {@code '+'} (<code>'\u002B'</code>) to
465 * indicate a positive value. The resulting {@code long} value is
466 * returned, exactly as if the argument and the radix {@code 10}
467 * were given as arguments to the {@link
468 * #parseLong(java.lang.String, int)} method.
469 *
470 * <p>Note that neither the character {@code L}
471 * (<code>'\u004C'</code>) nor {@code l}
472 * (<code>'\u006C'</code>) is permitted to appear at the end
473 * of the string as a type indicator, as would be permitted in
474 * Java programming language source code.
475 *
476 * @param s a {@code String} containing the {@code long}
477 * representation to be parsed
478 * @return the {@code long} represented by the argument in
479 * decimal.
480 * @throws NumberFormatException if the string does not contain a
481 * parsable {@code long}.
482 */
483 public static long parseLong(String s) throws NumberFormatException {
484 return parseLong(s, 10);
485 }
486
487 /**
488 * Returns a {@code Long} object holding the value
489 * extracted from the specified {@code String} when parsed
490 * with the radix given by the second argument. The first
491 * argument is interpreted as representing a signed
492 * {@code long} in the radix specified by the second
493 * argument, exactly as if the arguments were given to the {@link
494 * #parseLong(java.lang.String, int)} method. The result is a
495 * {@code Long} object that represents the {@code long}
496 * value specified by the string.
497 *
498 * <p>In other words, this method returns a {@code Long} object equal
499 * to the value of:
500 *
501 * <blockquote>
502 * {@code new Long(Long.parseLong(s, radix))}
503 * </blockquote>
504 *
505 * @param s the string to be parsed
506 * @param radix the radix to be used in interpreting {@code s}
507 * @return a {@code Long} object holding the value
508 * represented by the string argument in the specified
509 * radix.
510 * @throws NumberFormatException If the {@code String} does not
511 * contain a parsable {@code long}.
512 */
513 public static Long valueOf(String s, int radix) throws NumberFormatException {
514 return Long.valueOf(parseLong(s, radix));
515 }
516
517 /**
518 * Returns a {@code Long} object holding the value
519 * of the specified {@code String}. The argument is
520 * interpreted as representing a signed decimal {@code long},
521 * exactly as if the argument were given to the {@link
522 * #parseLong(java.lang.String)} method. The result is a
523 * {@code Long} object that represents the integer value
524 * specified by the string.
525 *
526 * <p>In other words, this method returns a {@code Long} object
527 * equal to the value of:
528 *
529 * <blockquote>
530 * {@code new Long(Long.parseLong(s))}
531 * </blockquote>
532 *
533 * @param s the string to be parsed.
534 * @return a {@code Long} object holding the value
535 * represented by the string argument.
536 * @throws NumberFormatException If the string cannot be parsed
537 * as a {@code long}.
538 */
539 public static Long valueOf(String s) throws NumberFormatException
540 {
541 return Long.valueOf(parseLong(s, 10));
542 }
543
544 private static class LongCache {
545 private LongCache(){}
546
547 static final Long cache[] = new Long[-(-128) + 127 + 1];
548
549 static {
550 for(int i = 0; i < cache.length; i++)
551 cache[i] = new Long(i - 128);
552 }
553 }
554
555 /**
556 * Returns a {@code Long} instance representing the specified
557 * {@code long} value.
558 * If a new {@code Long} instance is not required, this method
559 * should generally be used in preference to the constructor
560 * {@link #Long(long)}, as this method is likely to yield
561 * significantly better space and time performance by caching
562 * frequently requested values.
563 *
564 * Note that unlike the {@linkplain Integer#valueOf(int)
565 * corresponding method} in the {@code Integer} class, this method
566 * is <em>not</em> required to cache values within a particular
567 * range.
568 *
569 * @param l a long value.
570 * @return a {@code Long} instance representing {@code l}.
571 * @since 1.5
572 */
573 public static Long valueOf(long l) {
574 final int offset = 128;
575 if (l >= -128 && l <= 127) { // will cache
576 return LongCache.cache[(int)l + offset];
577 }
578 return new Long(l);
579 }
580
581 /**
582 * Decodes a {@code String} into a {@code Long}.
583 * Accepts decimal, hexadecimal, and octal numbers given by the
584 * following grammar:
585 *
586 * <blockquote>
587 * <dl>
588 * <dt><i>DecodableString:</i>
589 * <dd><i>Sign<sub>opt</sub> DecimalNumeral</i>
590 * <dd><i>Sign<sub>opt</sub></i> {@code 0x} <i>HexDigits</i>
591 * <dd><i>Sign<sub>opt</sub></i> {@code 0X} <i>HexDigits</i>
592 * <dd><i>Sign<sub>opt</sub></i> {@code #} <i>HexDigits</i>
593 * <dd><i>Sign<sub>opt</sub></i> {@code 0} <i>OctalDigits</i>
594 * <p>
595 * <dt><i>Sign:</i>
596 * <dd>{@code -}
597 * <dd>{@code +}
598 * </dl>
599 * </blockquote>
600 *
601 * <i>DecimalNumeral</i>, <i>HexDigits</i>, and <i>OctalDigits</i>
602 * are as defined in section 3.10.1 of
603 * <cite>The Java™ Language Specification</cite>,
604 * except that underscores are not accepted between digits.
605 *
606 * <p>The sequence of characters following an optional
607 * sign and/or radix specifier ("{@code 0x}", "{@code 0X}",
608 * "{@code #}", or leading zero) is parsed as by the {@code
609 * Long.parseLong} method with the indicated radix (10, 16, or 8).
610 * This sequence of characters must represent a positive value or
611 * a {@link NumberFormatException} will be thrown. The result is
612 * negated if first character of the specified {@code String} is
613 * the minus sign. No whitespace characters are permitted in the
614 * {@code String}.
615 *
616 * @param nm the {@code String} to decode.
617 * @return a {@code Long} object holding the {@code long}
618 * value represented by {@code nm}
619 * @throws NumberFormatException if the {@code String} does not
620 * contain a parsable {@code long}.
621 * @see java.lang.Long#parseLong(String, int)
622 * @since 1.2
623 */
624 public static Long decode(String nm) throws NumberFormatException {
625 int radix = 10;
626 int index = 0;
627 boolean negative = false;
628 Long result;
629
630 if (nm.length() == 0)
631 throw new NumberFormatException("Zero length string");
632 char firstChar = nm.charAt(0);
633 // Handle sign, if present
634 if (firstChar == '-') {
635 negative = true;
636 index++;
637 } else if (firstChar == '+')
638 index++;
639
640 // Handle radix specifier, if present
641 if (nm.startsWith("0x", index) || nm.startsWith("0X", index)) {
642 index += 2;
643 radix = 16;
644 }
645 else if (nm.startsWith("#", index)) {
646 index ++;
647 radix = 16;
648 }
649 else if (nm.startsWith("0", index) && nm.length() > 1 + index) {
650 index ++;
651 radix = 8;
652 }
653
654 if (nm.startsWith("-", index) || nm.startsWith("+", index))
655 throw new NumberFormatException("Sign character in wrong position");
656
657 try {
658 result = Long.valueOf(nm.substring(index), radix);
659 result = negative ? Long.valueOf(-result.longValue()) : result;
660 } catch (NumberFormatException e) {
661 // If number is Long.MIN_VALUE, we'll end up here. The next line
662 // handles this case, and causes any genuine format error to be
663 // rethrown.
664 String constant = negative ? ("-" + nm.substring(index))
665 : nm.substring(index);
666 result = Long.valueOf(constant, radix);
667 }
668 return result;
669 }
670
671 /**
672 * The value of the {@code Long}.
673 *
674 * @serial
675 */
676 private final long value;
677
678 /**
679 * Constructs a newly allocated {@code Long} object that
680 * represents the specified {@code long} argument.
681 *
682 * @param value the value to be represented by the
683 * {@code Long} object.
684 */
685 public Long(long value) {
686 this.value = value;
687 }
688
689 /**
690 * Constructs a newly allocated {@code Long} object that
691 * represents the {@code long} value indicated by the
692 * {@code String} parameter. The string is converted to a
693 * {@code long} value in exactly the manner used by the
694 * {@code parseLong} method for radix 10.
695 *
696 * @param s the {@code String} to be converted to a
697 * {@code Long}.
698 * @throws NumberFormatException if the {@code String} does not
699 * contain a parsable {@code long}.
700 * @see java.lang.Long#parseLong(java.lang.String, int)
701 */
702 public Long(String s) throws NumberFormatException {
703 this.value = parseLong(s, 10);
704 }
705
706 /**
707 * Returns the value of this {@code Long} as a {@code byte} after
708 * a narrowing primitive conversion.
709 * @jls 5.1.3 Narrowing Primitive Conversions
710 */
711 public byte byteValue() {
712 return (byte)value;
713 }
714
715 /**
716 * Returns the value of this {@code Long} as a {@code short} after
717 * a narrowing primitive conversion.
718 * @jls 5.1.3 Narrowing Primitive Conversions
719 */
720 public short shortValue() {
721 return (short)value;
722 }
723
724 /**
725 * Returns the value of this {@code Long} as an {@code int} after
726 * a narrowing primitive conversion.
727 * @jls 5.1.3 Narrowing Primitive Conversions
728 */
729 public int intValue() {
730 return (int)value;
731 }
732
733 /**
734 * Returns the value of this {@code Long} as a
735 * {@code long} value.
736 */
737 public long longValue() {
738 return value;
739 }
740
741 /**
742 * Returns the value of this {@code Long} as a {@code float} after
743 * a widening primitive conversion.
744 * @jls 5.1.2 Widening Primitive Conversions
745 */
746 public float floatValue() {
747 return (float)value;
748 }
749
750 /**
751 * Returns the value of this {@code Long} as a {@code double}
752 * after a widening primitive conversion.
753 * @jls 5.1.2 Widening Primitive Conversions
754 */
755 public double doubleValue() {
756 return (double)value;
757 }
758
759 /**
760 * Returns a {@code String} object representing this
761 * {@code Long}'s value. The value is converted to signed
762 * decimal representation and returned as a string, exactly as if
763 * the {@code long} value were given as an argument to the
764 * {@link java.lang.Long#toString(long)} method.
765 *
766 * @return a string representation of the value of this object in
767 * base 10.
768 */
769 public String toString() {
770 return toString(value);
771 }
772
773 /**
774 * Returns a hash code for this {@code Long}. The result is
775 * the exclusive OR of the two halves of the primitive
776 * {@code long} value held by this {@code Long}
777 * object. That is, the hashcode is the value of the expression:
778 *
779 * <blockquote>
780 * {@code (int)(this.longValue()^(this.longValue()>>>32))}
781 * </blockquote>
782 *
783 * @return a hash code value for this object.
784 */
785 public int hashCode() {
786 return (int)(value ^ (value >>> 32));
787 }
788
789 /**
790 * Compares this object to the specified object. The result is
791 * {@code true} if and only if the argument is not
792 * {@code null} and is a {@code Long} object that
793 * contains the same {@code long} value as this object.
794 *
795 * @param obj the object to compare with.
796 * @return {@code true} if the objects are the same;
797 * {@code false} otherwise.
798 */
799 public boolean equals(Object obj) {
800 if (obj instanceof Long) {
801 return value == ((Long)obj).longValue();
802 }
803 return false;
804 }
805
806 /**
807 * Determines the {@code long} value of the system property
808 * with the specified name.
809 *
810 * <p>The first argument is treated as the name of a system
811 * property. System properties are accessible through the {@link
812 * java.lang.System#getProperty(java.lang.String)} method. The
813 * string value of this property is then interpreted as a {@code
814 * long} value using the grammar supported by {@link Long#decode decode}
815 * and a {@code Long} object representing this value is returned.
816 *
817 * <p>If there is no property with the specified name, if the
818 * specified name is empty or {@code null}, or if the property
819 * does not have the correct numeric format, then {@code null} is
820 * returned.
821 *
822 * <p>In other words, this method returns a {@code Long} object
823 * equal to the value of:
824 *
825 * <blockquote>
826 * {@code getLong(nm, null)}
827 * </blockquote>
828 *
829 * @param nm property name.
830 * @return the {@code Long} value of the property.
831 * @throws SecurityException for the same reasons as
832 * {@link System#getProperty(String) System.getProperty}
833 * @see java.lang.System#getProperty(java.lang.String)
834 * @see java.lang.System#getProperty(java.lang.String, java.lang.String)
835 */
836 public static Long getLong(String nm) {
837 return getLong(nm, null);
838 }
839
840 /**
841 * Determines the {@code long} value of the system property
842 * with the specified name.
843 *
844 * <p>The first argument is treated as the name of a system
845 * property. System properties are accessible through the {@link
846 * java.lang.System#getProperty(java.lang.String)} method. The
847 * string value of this property is then interpreted as a {@code
848 * long} value using the grammar supported by {@link Long#decode decode}
849 * and a {@code Long} object representing this value is returned.
850 *
851 * <p>The second argument is the default value. A {@code Long} object
852 * that represents the value of the second argument is returned if there
853 * is no property of the specified name, if the property does not have
854 * the correct numeric format, or if the specified name is empty or null.
855 *
856 * <p>In other words, this method returns a {@code Long} object equal
857 * to the value of:
858 *
859 * <blockquote>
860 * {@code getLong(nm, new Long(val))}
861 * </blockquote>
862 *
863 * but in practice it may be implemented in a manner such as:
864 *
865 * <blockquote><pre>
866 * Long result = getLong(nm, null);
867 * return (result == null) ? new Long(val) : result;
868 * </pre></blockquote>
869 *
870 * to avoid the unnecessary allocation of a {@code Long} object when
871 * the default value is not needed.
872 *
873 * @param nm property name.
874 * @param val default value.
875 * @return the {@code Long} value of the property.
876 * @throws SecurityException for the same reasons as
877 * {@link System#getProperty(String) System.getProperty}
878 * @see java.lang.System#getProperty(java.lang.String)
879 * @see java.lang.System#getProperty(java.lang.String, java.lang.String)
880 */
881 public static Long getLong(String nm, long val) {
882 Long result = Long.getLong(nm, null);
883 return (result == null) ? Long.valueOf(val) : result;
884 }
885
886 /**
887 * Returns the {@code long} value of the system property with
888 * the specified name. The first argument is treated as the name
889 * of a system property. System properties are accessible through
890 * the {@link java.lang.System#getProperty(java.lang.String)}
891 * method. The string value of this property is then interpreted
892 * as a {@code long} value, as per the
893 * {@link Long#decode decode} method, and a {@code Long} object
894 * representing this value is returned; in summary:
895 *
896 * <ul>
897 * <li>If the property value begins with the two ASCII characters
898 * {@code 0x} or the ASCII character {@code #}, not followed by
899 * a minus sign, then the rest of it is parsed as a hexadecimal integer
900 * exactly as for the method {@link #valueOf(java.lang.String, int)}
901 * with radix 16.
902 * <li>If the property value begins with the ASCII character
903 * {@code 0} followed by another character, it is parsed as
904 * an octal integer exactly as by the method {@link
905 * #valueOf(java.lang.String, int)} with radix 8.
906 * <li>Otherwise the property value is parsed as a decimal
907 * integer exactly as by the method
908 * {@link #valueOf(java.lang.String, int)} with radix 10.
909 * </ul>
910 *
911 * <p>Note that, in every case, neither {@code L}
912 * (<code>'\u004C'</code>) nor {@code l}
913 * (<code>'\u006C'</code>) is permitted to appear at the end
914 * of the property value as a type indicator, as would be
915 * permitted in Java programming language source code.
916 *
917 * <p>The second argument is the default value. The default value is
918 * returned if there is no property of the specified name, if the
919 * property does not have the correct numeric format, or if the
920 * specified name is empty or {@code null}.
921 *
922 * @param nm property name.
923 * @param val default value.
924 * @return the {@code Long} value of the property.
925 * @throws SecurityException for the same reasons as
926 * {@link System#getProperty(String) System.getProperty}
927 * @see System#getProperty(java.lang.String)
928 * @see System#getProperty(java.lang.String, java.lang.String)
929 */
930 public static Long getLong(String nm, Long val) {
931 String v = null;
932 try {
933 v = System.getProperty(nm);
934 } catch (IllegalArgumentException | NullPointerException e) {
935 }
936 if (v != null) {
937 try {
938 return Long.decode(v);
939 } catch (NumberFormatException e) {
940 }
941 }
942 return val;
943 }
944
945 /**
946 * Compares two {@code Long} objects numerically.
947 *
948 * @param anotherLong the {@code Long} to be compared.
949 * @return the value {@code 0} if this {@code Long} is
950 * equal to the argument {@code Long}; a value less than
951 * {@code 0} if this {@code Long} is numerically less
952 * than the argument {@code Long}; and a value greater
953 * than {@code 0} if this {@code Long} is numerically
954 * greater than the argument {@code Long} (signed
955 * comparison).
956 * @since 1.2
957 */
958 public int compareTo(Long anotherLong) {
959 return compare(this.value, anotherLong.value);
960 }
961
962 /**
963 * Compares two {@code long} values numerically.
964 * The value returned is identical to what would be returned by:
965 * <pre>
966 * Long.valueOf(x).compareTo(Long.valueOf(y))
967 * </pre>
968 *
969 * @param x the first {@code long} to compare
970 * @param y the second {@code long} to compare
971 * @return the value {@code 0} if {@code x == y};
972 * a value less than {@code 0} if {@code x < y}; and
973 * a value greater than {@code 0} if {@code x > y}
974 * @since 1.7
975 */
976 public static int compare(long x, long y) {
977 return (x < y) ? -1 : ((x == y) ? 0 : 1);
978 }
979
980
981 // Bit Twiddling
982
983 /**
984 * The number of bits used to represent a {@code long} value in two's
985 * complement binary form.
986 *
987 * @since 1.5
988 */
989 public static final int SIZE = 64;
990
991 /**
992 * Returns a {@code long} value with at most a single one-bit, in the
993 * position of the highest-order ("leftmost") one-bit in the specified
994 * {@code long} value. Returns zero if the specified value has no
995 * one-bits in its two's complement binary representation, that is, if it
996 * is equal to zero.
997 *
998 * @return a {@code long} value with a single one-bit, in the position
999 * of the highest-order one-bit in the specified value, or zero if
1000 * the specified value is itself equal to zero.
1001 * @since 1.5
1002 */
1003 public static long highestOneBit(long i) {
1004 // HD, Figure 3-1
1005 i |= (i >> 1);
1006 i |= (i >> 2);
1007 i |= (i >> 4);
1008 i |= (i >> 8);
1009 i |= (i >> 16);
1010 i |= (i >> 32);
1011 return i - (i >>> 1);
1012 }
1013
1014 /**
1015 * Returns a {@code long} value with at most a single one-bit, in the
1016 * position of the lowest-order ("rightmost") one-bit in the specified
1017 * {@code long} value. Returns zero if the specified value has no
1018 * one-bits in its two's complement binary representation, that is, if it
1019 * is equal to zero.
1020 *
1021 * @return a {@code long} value with a single one-bit, in the position
1022 * of the lowest-order one-bit in the specified value, or zero if
1023 * the specified value is itself equal to zero.
1024 * @since 1.5
1025 */
1026 public static long lowestOneBit(long i) {
1027 // HD, Section 2-1
1028 return i & -i;
1029 }
1030
1031 /**
1032 * Returns the number of zero bits preceding the highest-order
1033 * ("leftmost") one-bit in the two's complement binary representation
1034 * of the specified {@code long} value. Returns 64 if the
1035 * specified value has no one-bits in its two's complement representation,
1036 * in other words if it is equal to zero.
1037 *
1038 * <p>Note that this method is closely related to the logarithm base 2.
1039 * For all positive {@code long} values x:
1040 * <ul>
1041 * <li>floor(log<sub>2</sub>(x)) = {@code 63 - numberOfLeadingZeros(x)}
1042 * <li>ceil(log<sub>2</sub>(x)) = {@code 64 - numberOfLeadingZeros(x - 1)}
1043 * </ul>
1044 *
1045 * @return the number of zero bits preceding the highest-order
1046 * ("leftmost") one-bit in the two's complement binary representation
1047 * of the specified {@code long} value, or 64 if the value
1048 * is equal to zero.
1049 * @since 1.5
1050 */
1051 public static int numberOfLeadingZeros(long i) {
1052 // HD, Figure 5-6
1053 if (i == 0)
1054 return 64;
1055 int n = 1;
1056 int x = (int)(i >>> 32);
1057 if (x == 0) { n += 32; x = (int)i; }
1058 if (x >>> 16 == 0) { n += 16; x <<= 16; }
1059 if (x >>> 24 == 0) { n += 8; x <<= 8; }
1060 if (x >>> 28 == 0) { n += 4; x <<= 4; }
1061 if (x >>> 30 == 0) { n += 2; x <<= 2; }
1062 n -= x >>> 31;
1063 return n;
1064 }
1065
1066 /**
1067 * Returns the number of zero bits following the lowest-order ("rightmost")
1068 * one-bit in the two's complement binary representation of the specified
1069 * {@code long} value. Returns 64 if the specified value has no
1070 * one-bits in its two's complement representation, in other words if it is
1071 * equal to zero.
1072 *
1073 * @return the number of zero bits following the lowest-order ("rightmost")
1074 * one-bit in the two's complement binary representation of the
1075 * specified {@code long} value, or 64 if the value is equal
1076 * to zero.
1077 * @since 1.5
1078 */
1079 public static int numberOfTrailingZeros(long i) {
1080 // HD, Figure 5-14
1081 int x, y;
1082 if (i == 0) return 64;
1083 int n = 63;
1084 y = (int)i; if (y != 0) { n = n -32; x = y; } else x = (int)(i>>>32);
1085 y = x <<16; if (y != 0) { n = n -16; x = y; }
1086 y = x << 8; if (y != 0) { n = n - 8; x = y; }
1087 y = x << 4; if (y != 0) { n = n - 4; x = y; }
1088 y = x << 2; if (y != 0) { n = n - 2; x = y; }
1089 return n - ((x << 1) >>> 31);
1090 }
1091
1092 /**
1093 * Returns the number of one-bits in the two's complement binary
1094 * representation of the specified {@code long} value. This function is
1095 * sometimes referred to as the <i>population count</i>.
1096 *
1097 * @return the number of one-bits in the two's complement binary
1098 * representation of the specified {@code long} value.
1099 * @since 1.5
1100 */
1101 public static int bitCount(long i) {
1102 // HD, Figure 5-14
1103 i = i - ((i >>> 1) & 0x5555555555555555L);
1104 i = (i & 0x3333333333333333L) + ((i >>> 2) & 0x3333333333333333L);
1105 i = (i + (i >>> 4)) & 0x0f0f0f0f0f0f0f0fL;
1106 i = i + (i >>> 8);
1107 i = i + (i >>> 16);
1108 i = i + (i >>> 32);
1109 return (int)i & 0x7f;
1110 }
1111
1112 /**
1113 * Returns the value obtained by rotating the two's complement binary
1114 * representation of the specified {@code long} value left by the
1115 * specified number of bits. (Bits shifted out of the left hand, or
1116 * high-order, side reenter on the right, or low-order.)
1117 *
1118 * <p>Note that left rotation with a negative distance is equivalent to
1119 * right rotation: {@code rotateLeft(val, -distance) == rotateRight(val,
1120 * distance)}. Note also that rotation by any multiple of 64 is a
1121 * no-op, so all but the last six bits of the rotation distance can be
1122 * ignored, even if the distance is negative: {@code rotateLeft(val,
1123 * distance) == rotateLeft(val, distance & 0x3F)}.
1124 *
1125 * @return the value obtained by rotating the two's complement binary
1126 * representation of the specified {@code long} value left by the
1127 * specified number of bits.
1128 * @since 1.5
1129 */
1130 public static long rotateLeft(long i, int distance) {
1131 return (i << distance) | (i >>> -distance);
1132 }
1133
1134 /**
1135 * Returns the value obtained by rotating the two's complement binary
1136 * representation of the specified {@code long} value right by the
1137 * specified number of bits. (Bits shifted out of the right hand, or
1138 * low-order, side reenter on the left, or high-order.)
1139 *
1140 * <p>Note that right rotation with a negative distance is equivalent to
1141 * left rotation: {@code rotateRight(val, -distance) == rotateLeft(val,
1142 * distance)}. Note also that rotation by any multiple of 64 is a
1143 * no-op, so all but the last six bits of the rotation distance can be
1144 * ignored, even if the distance is negative: {@code rotateRight(val,
1145 * distance) == rotateRight(val, distance & 0x3F)}.
1146 *
1147 * @return the value obtained by rotating the two's complement binary
1148 * representation of the specified {@code long} value right by the
1149 * specified number of bits.
1150 * @since 1.5
1151 */
1152 public static long rotateRight(long i, int distance) {
1153 return (i >>> distance) | (i << -distance);
1154 }
1155
1156 /**
1157 * Returns the value obtained by reversing the order of the bits in the
1158 * two's complement binary representation of the specified {@code long}
1159 * value.
1160 *
1161 * @return the value obtained by reversing order of the bits in the
1162 * specified {@code long} value.
1163 * @since 1.5
1164 */
1165 public static long reverse(long i) {
1166 // HD, Figure 7-1
1167 i = (i & 0x5555555555555555L) << 1 | (i >>> 1) & 0x5555555555555555L;
1168 i = (i & 0x3333333333333333L) << 2 | (i >>> 2) & 0x3333333333333333L;
1169 i = (i & 0x0f0f0f0f0f0f0f0fL) << 4 | (i >>> 4) & 0x0f0f0f0f0f0f0f0fL;
1170 i = (i & 0x00ff00ff00ff00ffL) << 8 | (i >>> 8) & 0x00ff00ff00ff00ffL;
1171 i = (i << 48) | ((i & 0xffff0000L) << 16) |
1172 ((i >>> 16) & 0xffff0000L) | (i >>> 48);
1173 return i;
1174 }
1175
1176 /**
1177 * Returns the signum function of the specified {@code long} value. (The
1178 * return value is -1 if the specified value is negative; 0 if the
1179 * specified value is zero; and 1 if the specified value is positive.)
1180 *
1181 * @return the signum function of the specified {@code long} value.
1182 * @since 1.5
1183 */
1184 public static int signum(long i) {
1185 // HD, Section 2-7
1186 return (int) ((i >> 63) | (-i >>> 63));
1187 }
1188
1189 /**
1190 * Returns the value obtained by reversing the order of the bytes in the
1191 * two's complement representation of the specified {@code long} value.
1192 *
1193 * @return the value obtained by reversing the bytes in the specified
1194 * {@code long} value.
1195 * @since 1.5
1196 */
1197 public static long reverseBytes(long i) {
1198 i = (i & 0x00ff00ff00ff00ffL) << 8 | (i >>> 8) & 0x00ff00ff00ff00ffL;
1199 return (i << 48) | ((i & 0xffff0000L) << 16) |
1200 ((i >>> 16) & 0xffff0000L) | (i >>> 48);
1201 }
1202
1203 /** use serialVersionUID from JDK 1.0.2 for interoperability */
1204 private static final long serialVersionUID = 4290774380558885855L;
1205 }