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