1 /* 2 * Copyright 1994-2008 Sun Microsystems, Inc. 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. Sun designates this 8 * particular file as subject to the "Classpath" exception as provided 9 * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, 22 * CA 95054 USA or visit www.sun.com if you need additional information or 23 * have any 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 defined in <a href="http://java.sun.com/docs/books/jls/second_edition/html/lexical.doc.html#48282">§3.10.1</a> 602 * of the <a href="http://java.sun.com/docs/books/jls/html/">Java 603 * Language Specification</a>. 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 707 * {@code byte}. 708 */ 709 public byte byteValue() { 710 return (byte)value; 711 } 712 713 /** 714 * Returns the value of this {@code Long} as a 715 * {@code short}. 716 */ 717 public short shortValue() { 718 return (short)value; 719 } 720 721 /** 722 * Returns the value of this {@code Long} as an 723 * {@code int}. 724 */ 725 public int intValue() { 726 return (int)value; 727 } 728 729 /** 730 * Returns the value of this {@code Long} as a 731 * {@code long} value. 732 */ 733 public long longValue() { 734 return (long)value; 735 } 736 737 /** 738 * Returns the value of this {@code Long} as a 739 * {@code float}. 740 */ 741 public float floatValue() { 742 return (float)value; 743 } 744 745 /** 746 * Returns the value of this {@code Long} as a 747 * {@code double}. 748 */ 749 public double doubleValue() { 750 return (double)value; 751 } 752 753 /** 754 * Returns a {@code String} object representing this 755 * {@code Long}'s value. The value is converted to signed 756 * decimal representation and returned as a string, exactly as if 757 * the {@code long} value were given as an argument to the 758 * {@link java.lang.Long#toString(long)} method. 759 * 760 * @return a string representation of the value of this object in 761 * base 10. 762 */ 763 public String toString() { 764 return String.valueOf(value); 765 } 766 767 /** 768 * Returns a hash code for this {@code Long}. The result is 769 * the exclusive OR of the two halves of the primitive 770 * {@code long} value held by this {@code Long} 771 * object. That is, the hashcode is the value of the expression: 772 * 773 * <blockquote> 774 * {@code (int)(this.longValue()^(this.longValue()>>>32))} 775 * </blockquote> 776 * 777 * @return a hash code value for this object. 778 */ 779 public int hashCode() { 780 return (int)(value ^ (value >>> 32)); 781 } 782 783 /** 784 * Compares this object to the specified object. The result is 785 * {@code true} if and only if the argument is not 786 * {@code null} and is a {@code Long} object that 787 * contains the same {@code long} value as this object. 788 * 789 * @param obj the object to compare with. 790 * @return {@code true} if the objects are the same; 791 * {@code false} otherwise. 792 */ 793 public boolean equals(Object obj) { 794 if (obj instanceof Long) { 795 return value == ((Long)obj).longValue(); 796 } 797 return false; 798 } 799 800 /** 801 * Determines the {@code long} value of the system property 802 * with the specified name. 803 * 804 * <p>The first argument is treated as the name of a system property. 805 * System properties are accessible through the {@link 806 * java.lang.System#getProperty(java.lang.String)} method. The 807 * string value of this property is then interpreted as a 808 * {@code long} value and a {@code Long} object 809 * representing this value is returned. Details of possible 810 * numeric formats can be found with the definition of 811 * {@code getProperty}. 812 * 813 * <p>If there is no property with the specified name, if the 814 * specified name is empty or {@code null}, or if the 815 * property does not have the correct numeric format, then 816 * {@code null} is returned. 817 * 818 * <p>In other words, this method returns a {@code Long} object equal to 819 * the value of: 820 * 821 * <blockquote> 822 * {@code getLong(nm, null)} 823 * </blockquote> 824 * 825 * @param nm property name. 826 * @return the {@code Long} value of the property. 827 * @see java.lang.System#getProperty(java.lang.String) 828 * @see java.lang.System#getProperty(java.lang.String, java.lang.String) 829 */ 830 public static Long getLong(String nm) { 831 return getLong(nm, null); 832 } 833 834 /** 835 * Determines the {@code long} value of the system property 836 * with the specified name. 837 * 838 * <p>The first argument is treated as the name of a system property. 839 * System properties are accessible through the {@link 840 * java.lang.System#getProperty(java.lang.String)} method. The 841 * string value of this property is then interpreted as a 842 * {@code long} value and a {@code Long} object 843 * representing this value is returned. Details of possible 844 * numeric formats can be found with the definition of 845 * {@code getProperty}. 846 * 847 * <p>The second argument is the default value. A {@code Long} object 848 * that represents the value of the second argument is returned if there 849 * is no property of the specified name, if the property does not have 850 * the correct numeric format, or if the specified name is empty or null. 851 * 852 * <p>In other words, this method returns a {@code Long} object equal 853 * to the value of: 854 * 855 * <blockquote> 856 * {@code getLong(nm, new Long(val))} 857 * </blockquote> 858 * 859 * but in practice it may be implemented in a manner such as: 860 * 861 * <blockquote><pre> 862 * Long result = getLong(nm, null); 863 * return (result == null) ? new Long(val) : result; 864 * </pre></blockquote> 865 * 866 * to avoid the unnecessary allocation of a {@code Long} object when 867 * the default value is not needed. 868 * 869 * @param nm property name. 870 * @param val default value. 871 * @return the {@code Long} value of the property. 872 * @see java.lang.System#getProperty(java.lang.String) 873 * @see java.lang.System#getProperty(java.lang.String, java.lang.String) 874 */ 875 public static Long getLong(String nm, long val) { 876 Long result = Long.getLong(nm, null); 877 return (result == null) ? Long.valueOf(val) : result; 878 } 879 880 /** 881 * Returns the {@code long} value of the system property with 882 * the specified name. The first argument is treated as the name 883 * of a system property. System properties are accessible through 884 * the {@link java.lang.System#getProperty(java.lang.String)} 885 * method. The string value of this property is then interpreted 886 * as a {@code long} value, as per the 887 * {@code Long.decode} method, and a {@code Long} object 888 * representing this value is returned. 889 * 890 * <ul> 891 * <li>If the property value begins with the two ASCII characters 892 * {@code 0x} or the ASCII character {@code #}, not followed by 893 * a minus sign, then the rest of it is parsed as a hexadecimal integer 894 * exactly as for the method {@link #valueOf(java.lang.String, int)} 895 * with radix 16. 896 * <li>If the property value begins with the ASCII character 897 * {@code 0} followed by another character, it is parsed as 898 * an octal integer exactly as by the method {@link 899 * #valueOf(java.lang.String, int)} with radix 8. 900 * <li>Otherwise the property value is parsed as a decimal 901 * integer exactly as by the method 902 * {@link #valueOf(java.lang.String, int)} with radix 10. 903 * </ul> 904 * 905 * <p>Note that, in every case, neither {@code L} 906 * (<code>'\u004C'</code>) nor {@code l} 907 * (<code>'\u006C'</code>) is permitted to appear at the end 908 * of the property value as a type indicator, as would be 909 * permitted in Java programming language source code. 910 * 911 * <p>The second argument is the default value. The default value is 912 * returned if there is no property of the specified name, if the 913 * property does not have the correct numeric format, or if the 914 * specified name is empty or {@code null}. 915 * 916 * @param nm property name. 917 * @param val default value. 918 * @return the {@code Long} value of the property. 919 * @see java.lang.System#getProperty(java.lang.String) 920 * @see java.lang.System#getProperty(java.lang.String, java.lang.String) 921 * @see java.lang.Long#decode 922 */ 923 public static Long getLong(String nm, Long val) { 924 String v = null; 925 try { 926 v = System.getProperty(nm); 927 } catch (IllegalArgumentException e) { 928 } catch (NullPointerException e) { 929 } 930 if (v != null) { 931 try { 932 return Long.decode(v); 933 } catch (NumberFormatException e) { 934 } 935 } 936 return val; 937 } 938 939 /** 940 * Compares two {@code Long} objects numerically. 941 * 942 * @param anotherLong the {@code Long} to be compared. 943 * @return the value {@code 0} if this {@code Long} is 944 * equal to the argument {@code Long}; a value less than 945 * {@code 0} if this {@code Long} is numerically less 946 * than the argument {@code Long}; and a value greater 947 * than {@code 0} if this {@code Long} is numerically 948 * greater than the argument {@code Long} (signed 949 * comparison). 950 * @since 1.2 951 */ 952 public int compareTo(Long anotherLong) { 953 long thisVal = this.value; 954 long anotherVal = anotherLong.value; 955 return (thisVal<anotherVal ? -1 : (thisVal==anotherVal ? 0 : 1)); 956 } 957 958 959 // Bit Twiddling 960 961 /** 962 * The number of bits used to represent a {@code long} value in two's 963 * complement binary form. 964 * 965 * @since 1.5 966 */ 967 public static final int SIZE = 64; 968 969 /** 970 * Returns a {@code long} value with at most a single one-bit, in the 971 * position of the highest-order ("leftmost") one-bit in the specified 972 * {@code long} value. Returns zero if the specified value has no 973 * one-bits in its two's complement binary representation, that is, if it 974 * is equal to zero. 975 * 976 * @return a {@code long} value with a single one-bit, in the position 977 * of the highest-order one-bit in the specified value, or zero if 978 * the specified value is itself equal to zero. 979 * @since 1.5 980 */ 981 public static long highestOneBit(long i) { 982 // HD, Figure 3-1 983 i |= (i >> 1); 984 i |= (i >> 2); 985 i |= (i >> 4); 986 i |= (i >> 8); 987 i |= (i >> 16); 988 i |= (i >> 32); 989 return i - (i >>> 1); 990 } 991 992 /** 993 * Returns a {@code long} value with at most a single one-bit, in the 994 * position of the lowest-order ("rightmost") one-bit in the specified 995 * {@code long} value. Returns zero if the specified value has no 996 * one-bits in its two's complement binary representation, that is, if it 997 * is equal to zero. 998 * 999 * @return a {@code long} value with a single one-bit, in the position 1000 * of the lowest-order one-bit in the specified value, or zero if 1001 * the specified value is itself equal to zero. 1002 * @since 1.5 1003 */ 1004 public static long lowestOneBit(long i) { 1005 // HD, Section 2-1 1006 return i & -i; 1007 } 1008 1009 /** 1010 * Returns the number of zero bits preceding the highest-order 1011 * ("leftmost") one-bit in the two's complement binary representation 1012 * of the specified {@code long} value. Returns 64 if the 1013 * specified value has no one-bits in its two's complement representation, 1014 * in other words if it is equal to zero. 1015 * 1016 * <p>Note that this method is closely related to the logarithm base 2. 1017 * For all positive {@code long} values x: 1018 * <ul> 1019 * <li>floor(log<sub>2</sub>(x)) = {@code 63 - numberOfLeadingZeros(x)} 1020 * <li>ceil(log<sub>2</sub>(x)) = {@code 64 - numberOfLeadingZeros(x - 1)} 1021 * </ul> 1022 * 1023 * @return the number of zero bits preceding the highest-order 1024 * ("leftmost") one-bit in the two's complement binary representation 1025 * of the specified {@code long} value, or 64 if the value 1026 * is equal to zero. 1027 * @since 1.5 1028 */ 1029 public static int numberOfLeadingZeros(long i) { 1030 // HD, Figure 5-6 1031 if (i == 0) 1032 return 64; 1033 int n = 1; 1034 int x = (int)(i >>> 32); 1035 if (x == 0) { n += 32; x = (int)i; } 1036 if (x >>> 16 == 0) { n += 16; x <<= 16; } 1037 if (x >>> 24 == 0) { n += 8; x <<= 8; } 1038 if (x >>> 28 == 0) { n += 4; x <<= 4; } 1039 if (x >>> 30 == 0) { n += 2; x <<= 2; } 1040 n -= x >>> 31; 1041 return n; 1042 } 1043 1044 /** 1045 * Returns the number of zero bits following the lowest-order ("rightmost") 1046 * one-bit in the two's complement binary representation of the specified 1047 * {@code long} value. Returns 64 if the specified value has no 1048 * one-bits in its two's complement representation, in other words if it is 1049 * equal to zero. 1050 * 1051 * @return the number of zero bits following the lowest-order ("rightmost") 1052 * one-bit in the two's complement binary representation of the 1053 * specified {@code long} value, or 64 if the value is equal 1054 * to zero. 1055 * @since 1.5 1056 */ 1057 public static int numberOfTrailingZeros(long i) { 1058 // HD, Figure 5-14 1059 int x, y; 1060 if (i == 0) return 64; 1061 int n = 63; 1062 y = (int)i; if (y != 0) { n = n -32; x = y; } else x = (int)(i>>>32); 1063 y = x <<16; if (y != 0) { n = n -16; x = y; } 1064 y = x << 8; if (y != 0) { n = n - 8; x = y; } 1065 y = x << 4; if (y != 0) { n = n - 4; x = y; } 1066 y = x << 2; if (y != 0) { n = n - 2; x = y; } 1067 return n - ((x << 1) >>> 31); 1068 } 1069 1070 /** 1071 * Returns the number of one-bits in the two's complement binary 1072 * representation of the specified {@code long} value. This function is 1073 * sometimes referred to as the <i>population count</i>. 1074 * 1075 * @return the number of one-bits in the two's complement binary 1076 * representation of the specified {@code long} value. 1077 * @since 1.5 1078 */ 1079 public static int bitCount(long i) { 1080 // HD, Figure 5-14 1081 i = i - ((i >>> 1) & 0x5555555555555555L); 1082 i = (i & 0x3333333333333333L) + ((i >>> 2) & 0x3333333333333333L); 1083 i = (i + (i >>> 4)) & 0x0f0f0f0f0f0f0f0fL; 1084 i = i + (i >>> 8); 1085 i = i + (i >>> 16); 1086 i = i + (i >>> 32); 1087 return (int)i & 0x7f; 1088 } 1089 1090 /** 1091 * Returns the value obtained by rotating the two's complement binary 1092 * representation of the specified {@code long} value left by the 1093 * specified number of bits. (Bits shifted out of the left hand, or 1094 * high-order, side reenter on the right, or low-order.) 1095 * 1096 * <p>Note that left rotation with a negative distance is equivalent to 1097 * right rotation: {@code rotateLeft(val, -distance) == rotateRight(val, 1098 * distance)}. Note also that rotation by any multiple of 64 is a 1099 * no-op, so all but the last six bits of the rotation distance can be 1100 * ignored, even if the distance is negative: {@code rotateLeft(val, 1101 * distance) == rotateLeft(val, distance & 0x3F)}. 1102 * 1103 * @return the value obtained by rotating the two's complement binary 1104 * representation of the specified {@code long} value left by the 1105 * specified number of bits. 1106 * @since 1.5 1107 */ 1108 public static long rotateLeft(long i, int distance) { 1109 return (i << distance) | (i >>> -distance); 1110 } 1111 1112 /** 1113 * Returns the value obtained by rotating the two's complement binary 1114 * representation of the specified {@code long} value right by the 1115 * specified number of bits. (Bits shifted out of the right hand, or 1116 * low-order, side reenter on the left, or high-order.) 1117 * 1118 * <p>Note that right rotation with a negative distance is equivalent to 1119 * left rotation: {@code rotateRight(val, -distance) == rotateLeft(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 rotateRight(val, 1123 * distance) == rotateRight(val, distance & 0x3F)}. 1124 * 1125 * @return the value obtained by rotating the two's complement binary 1126 * representation of the specified {@code long} value right by the 1127 * specified number of bits. 1128 * @since 1.5 1129 */ 1130 public static long rotateRight(long i, int distance) { 1131 return (i >>> distance) | (i << -distance); 1132 } 1133 1134 /** 1135 * Returns the value obtained by reversing the order of the bits in the 1136 * two's complement binary representation of the specified {@code long} 1137 * value. 1138 * 1139 * @return the value obtained by reversing order of the bits in the 1140 * specified {@code long} value. 1141 * @since 1.5 1142 */ 1143 public static long reverse(long i) { 1144 // HD, Figure 7-1 1145 i = (i & 0x5555555555555555L) << 1 | (i >>> 1) & 0x5555555555555555L; 1146 i = (i & 0x3333333333333333L) << 2 | (i >>> 2) & 0x3333333333333333L; 1147 i = (i & 0x0f0f0f0f0f0f0f0fL) << 4 | (i >>> 4) & 0x0f0f0f0f0f0f0f0fL; 1148 i = (i & 0x00ff00ff00ff00ffL) << 8 | (i >>> 8) & 0x00ff00ff00ff00ffL; 1149 i = (i << 48) | ((i & 0xffff0000L) << 16) | 1150 ((i >>> 16) & 0xffff0000L) | (i >>> 48); 1151 return i; 1152 } 1153 1154 /** 1155 * Returns the signum function of the specified {@code long} value. (The 1156 * return value is -1 if the specified value is negative; 0 if the 1157 * specified value is zero; and 1 if the specified value is positive.) 1158 * 1159 * @return the signum function of the specified {@code long} value. 1160 * @since 1.5 1161 */ 1162 public static int signum(long i) { 1163 // HD, Section 2-7 1164 return (int) ((i >> 63) | (-i >>> 63)); 1165 } 1166 1167 /** 1168 * Returns the value obtained by reversing the order of the bytes in the 1169 * two's complement representation of the specified {@code long} value. 1170 * 1171 * @return the value obtained by reversing the bytes in the specified 1172 * {@code long} value. 1173 * @since 1.5 1174 */ 1175 public static long reverseBytes(long i) { 1176 i = (i & 0x00ff00ff00ff00ffL) << 8 | (i >>> 8) & 0x00ff00ff00ff00ffL; 1177 return (i << 48) | ((i & 0xffff0000L) << 16) | 1178 ((i >>> 16) & 0xffff0000L) | (i >>> 48); 1179 } 1180 1181 /** use serialVersionUID from JDK 1.0.2 for interoperability */ 1182 private static final long serialVersionUID = 4290774380558885855L; 1183 }