emul/mini/src/main/java/java/lang/Long.java
author Jaroslav Tulach <jaroslav.tulach@apidesign.org>
Wed, 23 Jan 2013 20:39:23 +0100
branchemul
changeset 554 05224402145d
parent 179 emul/src/main/java/java/lang/Long.java@469199c2994a
child 675 7d3da112e2c1
permissions -rw-r--r--
First attempt to separate 'mini' profile from the rest of JDK APIs
     1 /*
     2  * Copyright (c) 1994, 2009, Oracle and/or its affiliates. All rights reserved.
     3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
     4  *
     5  * This code is free software; you can redistribute it and/or modify it
     6  * under the terms of the GNU General Public License version 2 only, as
     7  * published by the Free Software Foundation.  Oracle designates this
     8  * particular file as subject to the "Classpath" exception as provided
     9  * by Oracle in the LICENSE file that accompanied this code.
    10  *
    11  * This code is distributed in the hope that it will be useful, but WITHOUT
    12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
    13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
    14  * version 2 for more details (a copy is included in the LICENSE file that
    15  * accompanied this code).
    16  *
    17  * You should have received a copy of the GNU General Public License version
    18  * 2 along with this work; if not, write to the Free Software Foundation,
    19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
    20  *
    21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
    22  * or visit www.oracle.com if you need additional information or have any
    23  * questions.
    24  */
    25 
    26 package java.lang;
    27 
    28 import org.apidesign.bck2brwsr.core.JavaScriptBody;
    29 
    30 /**
    31  * The {@code Long} class wraps a value of the primitive type {@code
    32  * long} in an object. An object of type {@code Long} contains a
    33  * single field whose type is {@code long}.
    34  *
    35  * <p> In addition, this class provides several methods for converting
    36  * a {@code long} to a {@code String} and a {@code String} to a {@code
    37  * long}, as well as other constants and methods useful when dealing
    38  * with a {@code long}.
    39  *
    40  * <p>Implementation note: The implementations of the "bit twiddling"
    41  * methods (such as {@link #highestOneBit(long) highestOneBit} and
    42  * {@link #numberOfTrailingZeros(long) numberOfTrailingZeros}) are
    43  * based on material from Henry S. Warren, Jr.'s <i>Hacker's
    44  * Delight</i>, (Addison Wesley, 2002).
    45  *
    46  * @author  Lee Boynton
    47  * @author  Arthur van Hoff
    48  * @author  Josh Bloch
    49  * @author  Joseph D. Darcy
    50  * @since   JDK1.0
    51  */
    52 public final class Long extends Number implements Comparable<Long> {
    53     /**
    54      * A constant holding the minimum value a {@code long} can
    55      * have, -2<sup>63</sup>.
    56      */
    57     public static final long MIN_VALUE = 0x8000000000000000L;
    58 
    59     /**
    60      * A constant holding the maximum value a {@code long} can
    61      * have, 2<sup>63</sup>-1.
    62      */
    63     public static final long MAX_VALUE = 0x7fffffffffffffffL;
    64 
    65     /**
    66      * The {@code Class} instance representing the primitive type
    67      * {@code long}.
    68      *
    69      * @since   JDK1.1
    70      */
    71     public static final Class<Long>     TYPE = (Class<Long>) Class.getPrimitiveClass("long");
    72 
    73     /**
    74      * Returns a string representation of the first argument in the
    75      * radix specified by the second argument.
    76      *
    77      * <p>If the radix is smaller than {@code Character.MIN_RADIX}
    78      * or larger than {@code Character.MAX_RADIX}, then the radix
    79      * {@code 10} is used instead.
    80      *
    81      * <p>If the first argument is negative, the first element of the
    82      * result is the ASCII minus sign {@code '-'}
    83      * (<code>'&#92;u002d'</code>). If the first argument is not
    84      * negative, no sign character appears in the result.
    85      *
    86      * <p>The remaining characters of the result represent the magnitude
    87      * of the first argument. If the magnitude is zero, it is
    88      * represented by a single zero character {@code '0'}
    89      * (<code>'&#92;u0030'</code>); otherwise, the first character of
    90      * the representation of the magnitude will not be the zero
    91      * character.  The following ASCII characters are used as digits:
    92      *
    93      * <blockquote>
    94      *   {@code 0123456789abcdefghijklmnopqrstuvwxyz}
    95      * </blockquote>
    96      *
    97      * These are <code>'&#92;u0030'</code> through
    98      * <code>'&#92;u0039'</code> and <code>'&#92;u0061'</code> through
    99      * <code>'&#92;u007a'</code>. If {@code radix} is
   100      * <var>N</var>, then the first <var>N</var> of these characters
   101      * are used as radix-<var>N</var> digits in the order shown. Thus,
   102      * the digits for hexadecimal (radix 16) are
   103      * {@code 0123456789abcdef}. If uppercase letters are
   104      * desired, the {@link java.lang.String#toUpperCase()} method may
   105      * be called on the result:
   106      *
   107      * <blockquote>
   108      *  {@code Long.toString(n, 16).toUpperCase()}
   109      * </blockquote>
   110      *
   111      * @param   i       a {@code long} to be converted to a string.
   112      * @param   radix   the radix to use in the string representation.
   113      * @return  a string representation of the argument in the specified radix.
   114      * @see     java.lang.Character#MAX_RADIX
   115      * @see     java.lang.Character#MIN_RADIX
   116      */
   117     public static String toString(long i, int radix) {
   118         if (radix < Character.MIN_RADIX || radix > Character.MAX_RADIX)
   119             radix = 10;
   120         if (radix == 10)
   121             return toString(i);
   122         char[] buf = new char[65];
   123         int charPos = 64;
   124         boolean negative = (i < 0);
   125 
   126         if (!negative) {
   127             i = -i;
   128         }
   129 
   130         while (i <= -radix) {
   131             buf[charPos--] = Integer.digits[(int)(-(i % radix))];
   132             i = i / radix;
   133         }
   134         buf[charPos] = Integer.digits[(int)(-i)];
   135 
   136         if (negative) {
   137             buf[--charPos] = '-';
   138         }
   139 
   140         return new String(buf, charPos, (65 - charPos));
   141     }
   142 
   143     /**
   144      * Returns a string representation of the {@code long}
   145      * argument as an unsigned integer in base&nbsp;16.
   146      *
   147      * <p>The unsigned {@code long} value is the argument plus
   148      * 2<sup>64</sup> if the argument is negative; otherwise, it is
   149      * equal to the argument.  This value is converted to a string of
   150      * ASCII digits in hexadecimal (base&nbsp;16) with no extra
   151      * leading {@code 0}s.  If the unsigned magnitude is zero, it
   152      * is represented by a single zero character {@code '0'}
   153      * (<code>'&#92;u0030'</code>); otherwise, the first character of
   154      * the representation of the unsigned magnitude will not be the
   155      * zero character. The following characters are used as
   156      * hexadecimal digits:
   157      *
   158      * <blockquote>
   159      *  {@code 0123456789abcdef}
   160      * </blockquote>
   161      *
   162      * These are the characters <code>'&#92;u0030'</code> through
   163      * <code>'&#92;u0039'</code> and  <code>'&#92;u0061'</code> through
   164      * <code>'&#92;u0066'</code>.  If uppercase letters are desired,
   165      * the {@link java.lang.String#toUpperCase()} method may be called
   166      * on the result:
   167      *
   168      * <blockquote>
   169      *  {@code Long.toHexString(n).toUpperCase()}
   170      * </blockquote>
   171      *
   172      * @param   i   a {@code long} to be converted to a string.
   173      * @return  the string representation of the unsigned {@code long}
   174      *          value represented by the argument in hexadecimal
   175      *          (base&nbsp;16).
   176      * @since   JDK 1.0.2
   177      */
   178     public static String toHexString(long i) {
   179         return toUnsignedString(i, 4);
   180     }
   181 
   182     /**
   183      * Returns a string representation of the {@code long}
   184      * argument as an unsigned integer in base&nbsp;8.
   185      *
   186      * <p>The unsigned {@code long} value is the argument plus
   187      * 2<sup>64</sup> if the argument is negative; otherwise, it is
   188      * equal to the argument.  This value is converted to a string of
   189      * ASCII digits in octal (base&nbsp;8) with no extra leading
   190      * {@code 0}s.
   191      *
   192      * <p>If the unsigned magnitude is zero, it is represented by a
   193      * single zero character {@code '0'}
   194      * (<code>'&#92;u0030'</code>); otherwise, the first character of
   195      * the representation of the unsigned magnitude will not be the
   196      * zero character. The following characters are used as octal
   197      * digits:
   198      *
   199      * <blockquote>
   200      *  {@code 01234567}
   201      * </blockquote>
   202      *
   203      * These are the characters <code>'&#92;u0030'</code> through
   204      * <code>'&#92;u0037'</code>.
   205      *
   206      * @param   i   a {@code long} to be converted to a string.
   207      * @return  the string representation of the unsigned {@code long}
   208      *          value represented by the argument in octal (base&nbsp;8).
   209      * @since   JDK 1.0.2
   210      */
   211     public static String toOctalString(long i) {
   212         return toUnsignedString(i, 3);
   213     }
   214 
   215     /**
   216      * Returns a string representation of the {@code long}
   217      * argument as an unsigned integer in base&nbsp;2.
   218      *
   219      * <p>The unsigned {@code long} value is the argument plus
   220      * 2<sup>64</sup> if the argument is negative; otherwise, it is
   221      * equal to the argument.  This value is converted to a string of
   222      * ASCII digits in binary (base&nbsp;2) with no extra leading
   223      * {@code 0}s.  If the unsigned magnitude is zero, it is
   224      * represented by a single zero character {@code '0'}
   225      * (<code>'&#92;u0030'</code>); otherwise, the first character of
   226      * the representation of the unsigned magnitude will not be the
   227      * zero character. The characters {@code '0'}
   228      * (<code>'&#92;u0030'</code>) and {@code '1'}
   229      * (<code>'&#92;u0031'</code>) are used as binary digits.
   230      *
   231      * @param   i   a {@code long} to be converted to a string.
   232      * @return  the string representation of the unsigned {@code long}
   233      *          value represented by the argument in binary (base&nbsp;2).
   234      * @since   JDK 1.0.2
   235      */
   236     public static String toBinaryString(long i) {
   237         return toUnsignedString(i, 1);
   238     }
   239 
   240     /**
   241      * Convert the integer to an unsigned number.
   242      */
   243     private static String toUnsignedString(long i, int shift) {
   244         char[] buf = new char[64];
   245         int charPos = 64;
   246         int radix = 1 << shift;
   247         long mask = radix - 1;
   248         do {
   249             buf[--charPos] = Integer.digits[(int)(i & mask)];
   250             i >>>= shift;
   251         } while (i != 0);
   252         return new String(buf, charPos, (64 - charPos));
   253     }
   254 
   255     /**
   256      * Returns a {@code String} object representing the specified
   257      * {@code long}.  The argument is converted to signed decimal
   258      * representation and returned as a string, exactly as if the
   259      * argument and the radix 10 were given as arguments to the {@link
   260      * #toString(long, int)} method.
   261      *
   262      * @param   i   a {@code long} to be converted.
   263      * @return  a string representation of the argument in base&nbsp;10.
   264      */
   265     @JavaScriptBody(args = "i", body = "return i.toString();")
   266     public static String toString(long i) {
   267         if (i == Long.MIN_VALUE)
   268             return "-9223372036854775808";
   269         int size = (i < 0) ? stringSize(-i) + 1 : stringSize(i);
   270         char[] buf = new char[size];
   271         getChars(i, size, buf);
   272         return new String(buf, 0, size);
   273     }
   274 
   275     /**
   276      * Places characters representing the integer i into the
   277      * character array buf. The characters are placed into
   278      * the buffer backwards starting with the least significant
   279      * digit at the specified index (exclusive), and working
   280      * backwards from there.
   281      *
   282      * Will fail if i == Long.MIN_VALUE
   283      */
   284     static void getChars(long i, int index, char[] buf) {
   285         long q;
   286         int r;
   287         int charPos = index;
   288         char sign = 0;
   289 
   290         if (i < 0) {
   291             sign = '-';
   292             i = -i;
   293         }
   294 
   295         // Get 2 digits/iteration using longs until quotient fits into an int
   296         while (i > Integer.MAX_VALUE) {
   297             q = i / 100;
   298             // really: r = i - (q * 100);
   299             r = (int)(i - ((q << 6) + (q << 5) + (q << 2)));
   300             i = q;
   301             buf[--charPos] = Integer.DigitOnes[r];
   302             buf[--charPos] = Integer.DigitTens[r];
   303         }
   304 
   305         // Get 2 digits/iteration using ints
   306         int q2;
   307         int i2 = (int)i;
   308         while (i2 >= 65536) {
   309             q2 = i2 / 100;
   310             // really: r = i2 - (q * 100);
   311             r = i2 - ((q2 << 6) + (q2 << 5) + (q2 << 2));
   312             i2 = q2;
   313             buf[--charPos] = Integer.DigitOnes[r];
   314             buf[--charPos] = Integer.DigitTens[r];
   315         }
   316 
   317         // Fall thru to fast mode for smaller numbers
   318         // assert(i2 <= 65536, i2);
   319         for (;;) {
   320             q2 = (i2 * 52429) >>> (16+3);
   321             r = i2 - ((q2 << 3) + (q2 << 1));  // r = i2-(q2*10) ...
   322             buf[--charPos] = Integer.digits[r];
   323             i2 = q2;
   324             if (i2 == 0) break;
   325         }
   326         if (sign != 0) {
   327             buf[--charPos] = sign;
   328         }
   329     }
   330 
   331     // Requires positive x
   332     static int stringSize(long x) {
   333         long p = 10;
   334         for (int i=1; i<19; i++) {
   335             if (x < p)
   336                 return i;
   337             p = 10*p;
   338         }
   339         return 19;
   340     }
   341 
   342     /**
   343      * Parses the string argument as a signed {@code long} in the
   344      * radix specified by the second argument. The characters in the
   345      * string must all be digits of the specified radix (as determined
   346      * by whether {@link java.lang.Character#digit(char, int)} returns
   347      * a nonnegative value), except that the first character may be an
   348      * ASCII minus sign {@code '-'} (<code>'&#92;u002D'</code>) to
   349      * indicate a negative value or an ASCII plus sign {@code '+'}
   350      * (<code>'&#92;u002B'</code>) to indicate a positive value. The
   351      * resulting {@code long} value is returned.
   352      *
   353      * <p>Note that neither the character {@code L}
   354      * (<code>'&#92;u004C'</code>) nor {@code l}
   355      * (<code>'&#92;u006C'</code>) is permitted to appear at the end
   356      * of the string as a type indicator, as would be permitted in
   357      * Java programming language source code - except that either
   358      * {@code L} or {@code l} may appear as a digit for a
   359      * radix greater than 22.
   360      *
   361      * <p>An exception of type {@code NumberFormatException} is
   362      * thrown if any of the following situations occurs:
   363      * <ul>
   364      *
   365      * <li>The first argument is {@code null} or is a string of
   366      * length zero.
   367      *
   368      * <li>The {@code radix} is either smaller than {@link
   369      * java.lang.Character#MIN_RADIX} or larger than {@link
   370      * java.lang.Character#MAX_RADIX}.
   371      *
   372      * <li>Any character of the string is not a digit of the specified
   373      * radix, except that the first character may be a minus sign
   374      * {@code '-'} (<code>'&#92;u002d'</code>) or plus sign {@code
   375      * '+'} (<code>'&#92;u002B'</code>) provided that the string is
   376      * longer than length 1.
   377      *
   378      * <li>The value represented by the string is not a value of type
   379      *      {@code long}.
   380      * </ul>
   381      *
   382      * <p>Examples:
   383      * <blockquote><pre>
   384      * parseLong("0", 10) returns 0L
   385      * parseLong("473", 10) returns 473L
   386      * parseLong("+42", 10) returns 42L
   387      * parseLong("-0", 10) returns 0L
   388      * parseLong("-FF", 16) returns -255L
   389      * parseLong("1100110", 2) returns 102L
   390      * parseLong("99", 8) throws a NumberFormatException
   391      * parseLong("Hazelnut", 10) throws a NumberFormatException
   392      * parseLong("Hazelnut", 36) returns 1356099454469L
   393      * </pre></blockquote>
   394      *
   395      * @param      s       the {@code String} containing the
   396      *                     {@code long} representation to be parsed.
   397      * @param      radix   the radix to be used while parsing {@code s}.
   398      * @return     the {@code long} represented by the string argument in
   399      *             the specified radix.
   400      * @throws     NumberFormatException  if the string does not contain a
   401      *             parsable {@code long}.
   402      */
   403     public static long parseLong(String s, int radix)
   404               throws NumberFormatException
   405     {
   406         if (s == null) {
   407             throw new NumberFormatException("null");
   408         }
   409 
   410         if (radix < Character.MIN_RADIX) {
   411             throw new NumberFormatException("radix " + radix +
   412                                             " less than Character.MIN_RADIX");
   413         }
   414         if (radix > Character.MAX_RADIX) {
   415             throw new NumberFormatException("radix " + radix +
   416                                             " greater than Character.MAX_RADIX");
   417         }
   418 
   419         long result = 0;
   420         boolean negative = false;
   421         int i = 0, len = s.length();
   422         long limit = -Long.MAX_VALUE;
   423         long multmin;
   424         int digit;
   425 
   426         if (len > 0) {
   427             char firstChar = s.charAt(0);
   428             if (firstChar < '0') { // Possible leading "+" or "-"
   429                 if (firstChar == '-') {
   430                     negative = true;
   431                     limit = Long.MIN_VALUE;
   432                 } else if (firstChar != '+')
   433                     throw NumberFormatException.forInputString(s);
   434 
   435                 if (len == 1) // Cannot have lone "+" or "-"
   436                     throw NumberFormatException.forInputString(s);
   437                 i++;
   438             }
   439             multmin = limit / radix;
   440             while (i < len) {
   441                 // Accumulating negatively avoids surprises near MAX_VALUE
   442                 digit = Character.digit(s.charAt(i++),radix);
   443                 if (digit < 0) {
   444                     throw NumberFormatException.forInputString(s);
   445                 }
   446                 if (result < multmin) {
   447                     throw NumberFormatException.forInputString(s);
   448                 }
   449                 result *= radix;
   450                 if (result < limit + digit) {
   451                     throw NumberFormatException.forInputString(s);
   452                 }
   453                 result -= digit;
   454             }
   455         } else {
   456             throw NumberFormatException.forInputString(s);
   457         }
   458         return negative ? result : -result;
   459     }
   460 
   461     /**
   462      * Parses the string argument as a signed decimal {@code long}.
   463      * The characters in the string must all be decimal digits, except
   464      * that the first character may be an ASCII minus sign {@code '-'}
   465      * (<code>&#92;u002D'</code>) to indicate a negative value or an
   466      * ASCII plus sign {@code '+'} (<code>'&#92;u002B'</code>) to
   467      * indicate a positive value. The resulting {@code long} value is
   468      * returned, exactly as if the argument and the radix {@code 10}
   469      * were given as arguments to the {@link
   470      * #parseLong(java.lang.String, int)} method.
   471      *
   472      * <p>Note that neither the character {@code L}
   473      * (<code>'&#92;u004C'</code>) nor {@code l}
   474      * (<code>'&#92;u006C'</code>) is permitted to appear at the end
   475      * of the string as a type indicator, as would be permitted in
   476      * Java programming language source code.
   477      *
   478      * @param      s   a {@code String} containing the {@code long}
   479      *             representation to be parsed
   480      * @return     the {@code long} represented by the argument in
   481      *             decimal.
   482      * @throws     NumberFormatException  if the string does not contain a
   483      *             parsable {@code long}.
   484      */
   485     public static long parseLong(String s) throws NumberFormatException {
   486         return parseLong(s, 10);
   487     }
   488 
   489     /**
   490      * Returns a {@code Long} object holding the value
   491      * extracted from the specified {@code String} when parsed
   492      * with the radix given by the second argument.  The first
   493      * argument is interpreted as representing a signed
   494      * {@code long} in the radix specified by the second
   495      * argument, exactly as if the arguments were given to the {@link
   496      * #parseLong(java.lang.String, int)} method. The result is a
   497      * {@code Long} object that represents the {@code long}
   498      * value specified by the string.
   499      *
   500      * <p>In other words, this method returns a {@code Long} object equal
   501      * to the value of:
   502      *
   503      * <blockquote>
   504      *  {@code new Long(Long.parseLong(s, radix))}
   505      * </blockquote>
   506      *
   507      * @param      s       the string to be parsed
   508      * @param      radix   the radix to be used in interpreting {@code s}
   509      * @return     a {@code Long} object holding the value
   510      *             represented by the string argument in the specified
   511      *             radix.
   512      * @throws     NumberFormatException  If the {@code String} does not
   513      *             contain a parsable {@code long}.
   514      */
   515     public static Long valueOf(String s, int radix) throws NumberFormatException {
   516         return Long.valueOf(parseLong(s, radix));
   517     }
   518 
   519     /**
   520      * Returns a {@code Long} object holding the value
   521      * of the specified {@code String}. The argument is
   522      * interpreted as representing a signed decimal {@code long},
   523      * exactly as if the argument were given to the {@link
   524      * #parseLong(java.lang.String)} method. The result is a
   525      * {@code Long} object that represents the integer value
   526      * specified by the string.
   527      *
   528      * <p>In other words, this method returns a {@code Long} object
   529      * equal to the value of:
   530      *
   531      * <blockquote>
   532      *  {@code new Long(Long.parseLong(s))}
   533      * </blockquote>
   534      *
   535      * @param      s   the string to be parsed.
   536      * @return     a {@code Long} object holding the value
   537      *             represented by the string argument.
   538      * @throws     NumberFormatException  If the string cannot be parsed
   539      *             as a {@code long}.
   540      */
   541     public static Long valueOf(String s) throws NumberFormatException
   542     {
   543         return Long.valueOf(parseLong(s, 10));
   544     }
   545 
   546     private static class LongCache {
   547         private LongCache(){}
   548 
   549         static final Long cache[] = new Long[-(-128) + 127 + 1];
   550 
   551         static {
   552             for(int i = 0; i < cache.length; i++)
   553                 cache[i] = new Long(i - 128);
   554         }
   555     }
   556 
   557     /**
   558      * Returns a {@code Long} instance representing the specified
   559      * {@code long} value.
   560      * If a new {@code Long} instance is not required, this method
   561      * should generally be used in preference to the constructor
   562      * {@link #Long(long)}, as this method is likely to yield
   563      * significantly better space and time performance by caching
   564      * frequently requested values.
   565      *
   566      * Note that unlike the {@linkplain Integer#valueOf(int)
   567      * corresponding method} in the {@code Integer} class, this method
   568      * is <em>not</em> required to cache values within a particular
   569      * range.
   570      *
   571      * @param  l a long value.
   572      * @return a {@code Long} instance representing {@code l}.
   573      * @since  1.5
   574      */
   575     public static Long valueOf(long l) {
   576         final int offset = 128;
   577         if (l >= -128 && l <= 127) { // will cache
   578             return LongCache.cache[(int)l + offset];
   579         }
   580         return new Long(l);
   581     }
   582 
   583     /**
   584      * Decodes a {@code String} into a {@code Long}.
   585      * Accepts decimal, hexadecimal, and octal numbers given by the
   586      * following grammar:
   587      *
   588      * <blockquote>
   589      * <dl>
   590      * <dt><i>DecodableString:</i>
   591      * <dd><i>Sign<sub>opt</sub> DecimalNumeral</i>
   592      * <dd><i>Sign<sub>opt</sub></i> {@code 0x} <i>HexDigits</i>
   593      * <dd><i>Sign<sub>opt</sub></i> {@code 0X} <i>HexDigits</i>
   594      * <dd><i>Sign<sub>opt</sub></i> {@code #} <i>HexDigits</i>
   595      * <dd><i>Sign<sub>opt</sub></i> {@code 0} <i>OctalDigits</i>
   596      * <p>
   597      * <dt><i>Sign:</i>
   598      * <dd>{@code -}
   599      * <dd>{@code +}
   600      * </dl>
   601      * </blockquote>
   602      *
   603      * <i>DecimalNumeral</i>, <i>HexDigits</i>, and <i>OctalDigits</i>
   604      * are as defined in section 3.10.1 of
   605      * <cite>The Java&trade; Language Specification</cite>,
   606      * except that underscores are not accepted between digits.
   607      *
   608      * <p>The sequence of characters following an optional
   609      * sign and/or radix specifier ("{@code 0x}", "{@code 0X}",
   610      * "{@code #}", or leading zero) is parsed as by the {@code
   611      * Long.parseLong} method with the indicated radix (10, 16, or 8).
   612      * This sequence of characters must represent a positive value or
   613      * a {@link NumberFormatException} will be thrown.  The result is
   614      * negated if first character of the specified {@code String} is
   615      * the minus sign.  No whitespace characters are permitted in the
   616      * {@code String}.
   617      *
   618      * @param     nm the {@code String} to decode.
   619      * @return    a {@code Long} object holding the {@code long}
   620      *            value represented by {@code nm}
   621      * @throws    NumberFormatException  if the {@code String} does not
   622      *            contain a parsable {@code long}.
   623      * @see java.lang.Long#parseLong(String, int)
   624      * @since 1.2
   625      */
   626     public static Long decode(String nm) throws NumberFormatException {
   627         int radix = 10;
   628         int index = 0;
   629         boolean negative = false;
   630         Long result;
   631 
   632         if (nm.length() == 0)
   633             throw new NumberFormatException("Zero length string");
   634         char firstChar = nm.charAt(0);
   635         // Handle sign, if present
   636         if (firstChar == '-') {
   637             negative = true;
   638             index++;
   639         } else if (firstChar == '+')
   640             index++;
   641 
   642         // Handle radix specifier, if present
   643         if (nm.startsWith("0x", index) || nm.startsWith("0X", index)) {
   644             index += 2;
   645             radix = 16;
   646         }
   647         else if (nm.startsWith("#", index)) {
   648             index ++;
   649             radix = 16;
   650         }
   651         else if (nm.startsWith("0", index) && nm.length() > 1 + index) {
   652             index ++;
   653             radix = 8;
   654         }
   655 
   656         if (nm.startsWith("-", index) || nm.startsWith("+", index))
   657             throw new NumberFormatException("Sign character in wrong position");
   658 
   659         try {
   660             result = Long.valueOf(nm.substring(index), radix);
   661             result = negative ? Long.valueOf(-result.longValue()) : result;
   662         } catch (NumberFormatException e) {
   663             // If number is Long.MIN_VALUE, we'll end up here. The next line
   664             // handles this case, and causes any genuine format error to be
   665             // rethrown.
   666             String constant = negative ? ("-" + nm.substring(index))
   667                                        : nm.substring(index);
   668             result = Long.valueOf(constant, radix);
   669         }
   670         return result;
   671     }
   672 
   673     /**
   674      * The value of the {@code Long}.
   675      *
   676      * @serial
   677      */
   678     private final long value;
   679 
   680     /**
   681      * Constructs a newly allocated {@code Long} object that
   682      * represents the specified {@code long} argument.
   683      *
   684      * @param   value   the value to be represented by the
   685      *          {@code Long} object.
   686      */
   687     public Long(long value) {
   688         this.value = value;
   689     }
   690 
   691     /**
   692      * Constructs a newly allocated {@code Long} object that
   693      * represents the {@code long} value indicated by the
   694      * {@code String} parameter. The string is converted to a
   695      * {@code long} value in exactly the manner used by the
   696      * {@code parseLong} method for radix 10.
   697      *
   698      * @param      s   the {@code String} to be converted to a
   699      *             {@code Long}.
   700      * @throws     NumberFormatException  if the {@code String} does not
   701      *             contain a parsable {@code long}.
   702      * @see        java.lang.Long#parseLong(java.lang.String, int)
   703      */
   704     public Long(String s) throws NumberFormatException {
   705         this.value = parseLong(s, 10);
   706     }
   707 
   708     /**
   709      * Returns the value of this {@code Long} as a
   710      * {@code byte}.
   711      */
   712     public byte byteValue() {
   713         return (byte)value;
   714     }
   715 
   716     /**
   717      * Returns the value of this {@code Long} as a
   718      * {@code short}.
   719      */
   720     public short shortValue() {
   721         return (short)value;
   722     }
   723 
   724     /**
   725      * Returns the value of this {@code Long} as an
   726      * {@code int}.
   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
   742      * {@code float}.
   743      */
   744     public float floatValue() {
   745         return (float)value;
   746     }
   747 
   748     /**
   749      * Returns the value of this {@code Long} as a
   750      * {@code double}.
   751      */
   752     public double doubleValue() {
   753         return (double)value;
   754     }
   755 
   756     /**
   757      * Returns a {@code String} object representing this
   758      * {@code Long}'s value.  The value is converted to signed
   759      * decimal representation and returned as a string, exactly as if
   760      * the {@code long} value were given as an argument to the
   761      * {@link java.lang.Long#toString(long)} method.
   762      *
   763      * @return  a string representation of the value of this object in
   764      *          base&nbsp;10.
   765      */
   766     public String toString() {
   767         return toString(value);
   768     }
   769 
   770     /**
   771      * Returns a hash code for this {@code Long}. The result is
   772      * the exclusive OR of the two halves of the primitive
   773      * {@code long} value held by this {@code Long}
   774      * object. That is, the hashcode is the value of the expression:
   775      *
   776      * <blockquote>
   777      *  {@code (int)(this.longValue()^(this.longValue()>>>32))}
   778      * </blockquote>
   779      *
   780      * @return  a hash code value for this object.
   781      */
   782     public int hashCode() {
   783         return (int)(value ^ (value >>> 32));
   784     }
   785 
   786     /**
   787      * Compares this object to the specified object.  The result is
   788      * {@code true} if and only if the argument is not
   789      * {@code null} and is a {@code Long} object that
   790      * contains the same {@code long} value as this object.
   791      *
   792      * @param   obj   the object to compare with.
   793      * @return  {@code true} if the objects are the same;
   794      *          {@code false} otherwise.
   795      */
   796     public boolean equals(Object obj) {
   797         if (obj instanceof Long) {
   798             return value == ((Long)obj).longValue();
   799         }
   800         return false;
   801     }
   802 
   803     /**
   804      * Determines the {@code long} value of the system property
   805      * with the specified name.
   806      *
   807      * <p>The first argument is treated as the name of a system property.
   808      * System properties are accessible through the {@link
   809      * java.lang.System#getProperty(java.lang.String)} method. The
   810      * string value of this property is then interpreted as a
   811      * {@code long} value and a {@code Long} object
   812      * representing this value is returned.  Details of possible
   813      * numeric formats can be found with the definition of
   814      * {@code getProperty}.
   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
   818      * property does not have the correct numeric format, then
   819      * {@code null} is returned.
   820      *
   821      * <p>In other words, this method returns a {@code Long} object equal to
   822      * 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 property.
   842      * 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
   845      * {@code long} value and a {@code Long} object
   846      * representing this value is returned.  Details of possible
   847      * numeric formats can be found with the definition of
   848      * {@code getProperty}.
   849      *
   850      * <p>The second argument is the default value. A {@code Long} object
   851      * that represents the value of the second argument is returned if there
   852      * is no property of the specified name, if the property does not have
   853      * the correct numeric format, or if the specified name is empty or null.
   854      *
   855      * <p>In other words, this method returns a {@code Long} object equal
   856      * to the value of:
   857      *
   858      * <blockquote>
   859      *  {@code getLong(nm, new Long(val))}
   860      * </blockquote>
   861      *
   862      * but in practice it may be implemented in a manner such as:
   863      *
   864      * <blockquote><pre>
   865      * Long result = getLong(nm, null);
   866      * return (result == null) ? new Long(val) : result;
   867      * </pre></blockquote>
   868      *
   869      * to avoid the unnecessary allocation of a {@code Long} object when
   870      * the default value is not needed.
   871      *
   872      * @param   nm    property name.
   873      * @param   val   default value.
   874      * @return  the {@code Long} value of the property.
   875      * @see     java.lang.System#getProperty(java.lang.String)
   876      * @see     java.lang.System#getProperty(java.lang.String, java.lang.String)
   877      */
   878     public static Long getLong(String nm, long val) {
   879         Long result = Long.getLong(nm, null);
   880         return (result == null) ? Long.valueOf(val) : result;
   881     }
   882 
   883     /**
   884      * Returns the {@code long} value of the system property with
   885      * the specified name.  The first argument is treated as the name
   886      * of a system property.  System properties are accessible through
   887      * the {@link java.lang.System#getProperty(java.lang.String)}
   888      * method. The string value of this property is then interpreted
   889      * as a {@code long} value, as per the
   890      * {@code Long.decode} method, and a {@code Long} object
   891      * representing this value is returned.
   892      *
   893      * <ul>
   894      * <li>If the property value begins with the two ASCII characters
   895      * {@code 0x} or the ASCII character {@code #}, not followed by
   896      * a minus sign, then the rest of it is parsed as a hexadecimal integer
   897      * exactly as for the method {@link #valueOf(java.lang.String, int)}
   898      * with radix 16.
   899      * <li>If the property value begins with the ASCII character
   900      * {@code 0} followed by another character, it is parsed as
   901      * an octal integer exactly as by the method {@link
   902      * #valueOf(java.lang.String, int)} with radix 8.
   903      * <li>Otherwise the property value is parsed as a decimal
   904      * integer exactly as by the method
   905      * {@link #valueOf(java.lang.String, int)} with radix 10.
   906      * </ul>
   907      *
   908      * <p>Note that, in every case, neither {@code L}
   909      * (<code>'&#92;u004C'</code>) nor {@code l}
   910      * (<code>'&#92;u006C'</code>) is permitted to appear at the end
   911      * of the property value as a type indicator, as would be
   912      * permitted in Java programming language source code.
   913      *
   914      * <p>The second argument is the default value. The default value is
   915      * returned if there is no property of the specified name, if the
   916      * property does not have the correct numeric format, or if the
   917      * specified name is empty or {@code null}.
   918      *
   919      * @param   nm   property name.
   920      * @param   val   default value.
   921      * @return  the {@code Long} value of the property.
   922      * @see     java.lang.System#getProperty(java.lang.String)
   923      * @see java.lang.System#getProperty(java.lang.String, java.lang.String)
   924      * @see java.lang.Long#decode
   925      */
   926     public static Long getLong(String nm, Long val) {
   927         String v = null;
   928         try {
   929             v = AbstractStringBuilder.getProperty(nm);
   930         } catch (IllegalArgumentException e) {
   931         } catch (NullPointerException e) {
   932         }
   933         if (v != null) {
   934             try {
   935                 return Long.decode(v);
   936             } catch (NumberFormatException e) {
   937             }
   938         }
   939         return val;
   940     }
   941 
   942     /**
   943      * Compares two {@code Long} objects numerically.
   944      *
   945      * @param   anotherLong   the {@code Long} to be compared.
   946      * @return  the value {@code 0} if this {@code Long} is
   947      *          equal to the argument {@code Long}; a value less than
   948      *          {@code 0} if this {@code Long} is numerically less
   949      *          than the argument {@code Long}; and a value greater
   950      *          than {@code 0} if this {@code Long} is numerically
   951      *           greater than the argument {@code Long} (signed
   952      *           comparison).
   953      * @since   1.2
   954      */
   955     public int compareTo(Long anotherLong) {
   956         return compare(this.value, anotherLong.value);
   957     }
   958 
   959     /**
   960      * Compares two {@code long} values numerically.
   961      * The value returned is identical to what would be returned by:
   962      * <pre>
   963      *    Long.valueOf(x).compareTo(Long.valueOf(y))
   964      * </pre>
   965      *
   966      * @param  x the first {@code long} to compare
   967      * @param  y the second {@code long} to compare
   968      * @return the value {@code 0} if {@code x == y};
   969      *         a value less than {@code 0} if {@code x < y}; and
   970      *         a value greater than {@code 0} if {@code x > y}
   971      * @since 1.7
   972      */
   973     public static int compare(long x, long y) {
   974         return (x < y) ? -1 : ((x == y) ? 0 : 1);
   975     }
   976 
   977 
   978     // Bit Twiddling
   979 
   980     /**
   981      * The number of bits used to represent a {@code long} value in two's
   982      * complement binary form.
   983      *
   984      * @since 1.5
   985      */
   986     public static final int SIZE = 64;
   987 
   988     /**
   989      * Returns a {@code long} value with at most a single one-bit, in the
   990      * position of the highest-order ("leftmost") one-bit in the specified
   991      * {@code long} value.  Returns zero if the specified value has no
   992      * one-bits in its two's complement binary representation, that is, if it
   993      * is equal to zero.
   994      *
   995      * @return a {@code long} value with a single one-bit, in the position
   996      *     of the highest-order one-bit in the specified value, or zero if
   997      *     the specified value is itself equal to zero.
   998      * @since 1.5
   999      */
  1000     public static long highestOneBit(long i) {
  1001         // HD, Figure 3-1
  1002         i |= (i >>  1);
  1003         i |= (i >>  2);
  1004         i |= (i >>  4);
  1005         i |= (i >>  8);
  1006         i |= (i >> 16);
  1007         i |= (i >> 32);
  1008         return i - (i >>> 1);
  1009     }
  1010 
  1011     /**
  1012      * Returns a {@code long} value with at most a single one-bit, in the
  1013      * position of the lowest-order ("rightmost") one-bit in the specified
  1014      * {@code long} value.  Returns zero if the specified value has no
  1015      * one-bits in its two's complement binary representation, that is, if it
  1016      * is equal to zero.
  1017      *
  1018      * @return a {@code long} value with a single one-bit, in the position
  1019      *     of the lowest-order one-bit in the specified value, or zero if
  1020      *     the specified value is itself equal to zero.
  1021      * @since 1.5
  1022      */
  1023     public static long lowestOneBit(long i) {
  1024         // HD, Section 2-1
  1025         return i & -i;
  1026     }
  1027 
  1028     /**
  1029      * Returns the number of zero bits preceding the highest-order
  1030      * ("leftmost") one-bit in the two's complement binary representation
  1031      * of the specified {@code long} value.  Returns 64 if the
  1032      * specified value has no one-bits in its two's complement representation,
  1033      * in other words if it is equal to zero.
  1034      *
  1035      * <p>Note that this method is closely related to the logarithm base 2.
  1036      * For all positive {@code long} values x:
  1037      * <ul>
  1038      * <li>floor(log<sub>2</sub>(x)) = {@code 63 - numberOfLeadingZeros(x)}
  1039      * <li>ceil(log<sub>2</sub>(x)) = {@code 64 - numberOfLeadingZeros(x - 1)}
  1040      * </ul>
  1041      *
  1042      * @return the number of zero bits preceding the highest-order
  1043      *     ("leftmost") one-bit in the two's complement binary representation
  1044      *     of the specified {@code long} value, or 64 if the value
  1045      *     is equal to zero.
  1046      * @since 1.5
  1047      */
  1048     public static int numberOfLeadingZeros(long i) {
  1049         // HD, Figure 5-6
  1050          if (i == 0)
  1051             return 64;
  1052         int n = 1;
  1053         int x = (int)(i >>> 32);
  1054         if (x == 0) { n += 32; x = (int)i; }
  1055         if (x >>> 16 == 0) { n += 16; x <<= 16; }
  1056         if (x >>> 24 == 0) { n +=  8; x <<=  8; }
  1057         if (x >>> 28 == 0) { n +=  4; x <<=  4; }
  1058         if (x >>> 30 == 0) { n +=  2; x <<=  2; }
  1059         n -= x >>> 31;
  1060         return n;
  1061     }
  1062 
  1063     /**
  1064      * Returns the number of zero bits following the lowest-order ("rightmost")
  1065      * one-bit in the two's complement binary representation of the specified
  1066      * {@code long} value.  Returns 64 if the specified value has no
  1067      * one-bits in its two's complement representation, in other words if it is
  1068      * equal to zero.
  1069      *
  1070      * @return the number of zero bits following the lowest-order ("rightmost")
  1071      *     one-bit in the two's complement binary representation of the
  1072      *     specified {@code long} value, or 64 if the value is equal
  1073      *     to zero.
  1074      * @since 1.5
  1075      */
  1076     public static int numberOfTrailingZeros(long i) {
  1077         // HD, Figure 5-14
  1078         int x, y;
  1079         if (i == 0) return 64;
  1080         int n = 63;
  1081         y = (int)i; if (y != 0) { n = n -32; x = y; } else x = (int)(i>>>32);
  1082         y = x <<16; if (y != 0) { n = n -16; x = y; }
  1083         y = x << 8; if (y != 0) { n = n - 8; x = y; }
  1084         y = x << 4; if (y != 0) { n = n - 4; x = y; }
  1085         y = x << 2; if (y != 0) { n = n - 2; x = y; }
  1086         return n - ((x << 1) >>> 31);
  1087     }
  1088 
  1089     /**
  1090      * Returns the number of one-bits in the two's complement binary
  1091      * representation of the specified {@code long} value.  This function is
  1092      * sometimes referred to as the <i>population count</i>.
  1093      *
  1094      * @return the number of one-bits in the two's complement binary
  1095      *     representation of the specified {@code long} value.
  1096      * @since 1.5
  1097      */
  1098      public static int bitCount(long i) {
  1099         // HD, Figure 5-14
  1100         i = i - ((i >>> 1) & 0x5555555555555555L);
  1101         i = (i & 0x3333333333333333L) + ((i >>> 2) & 0x3333333333333333L);
  1102         i = (i + (i >>> 4)) & 0x0f0f0f0f0f0f0f0fL;
  1103         i = i + (i >>> 8);
  1104         i = i + (i >>> 16);
  1105         i = i + (i >>> 32);
  1106         return (int)i & 0x7f;
  1107      }
  1108 
  1109     /**
  1110      * Returns the value obtained by rotating the two's complement binary
  1111      * representation of the specified {@code long} value left by the
  1112      * specified number of bits.  (Bits shifted out of the left hand, or
  1113      * high-order, side reenter on the right, or low-order.)
  1114      *
  1115      * <p>Note that left rotation with a negative distance is equivalent to
  1116      * right rotation: {@code rotateLeft(val, -distance) == rotateRight(val,
  1117      * distance)}.  Note also that rotation by any multiple of 64 is a
  1118      * no-op, so all but the last six bits of the rotation distance can be
  1119      * ignored, even if the distance is negative: {@code rotateLeft(val,
  1120      * distance) == rotateLeft(val, distance & 0x3F)}.
  1121      *
  1122      * @return the value obtained by rotating the two's complement binary
  1123      *     representation of the specified {@code long} value left by the
  1124      *     specified number of bits.
  1125      * @since 1.5
  1126      */
  1127     public static long rotateLeft(long i, int distance) {
  1128         return (i << distance) | (i >>> -distance);
  1129     }
  1130 
  1131     /**
  1132      * Returns the value obtained by rotating the two's complement binary
  1133      * representation of the specified {@code long} value right by the
  1134      * specified number of bits.  (Bits shifted out of the right hand, or
  1135      * low-order, side reenter on the left, or high-order.)
  1136      *
  1137      * <p>Note that right rotation with a negative distance is equivalent to
  1138      * left rotation: {@code rotateRight(val, -distance) == rotateLeft(val,
  1139      * distance)}.  Note also that rotation by any multiple of 64 is a
  1140      * no-op, so all but the last six bits of the rotation distance can be
  1141      * ignored, even if the distance is negative: {@code rotateRight(val,
  1142      * distance) == rotateRight(val, distance & 0x3F)}.
  1143      *
  1144      * @return the value obtained by rotating the two's complement binary
  1145      *     representation of the specified {@code long} value right by the
  1146      *     specified number of bits.
  1147      * @since 1.5
  1148      */
  1149     public static long rotateRight(long i, int distance) {
  1150         return (i >>> distance) | (i << -distance);
  1151     }
  1152 
  1153     /**
  1154      * Returns the value obtained by reversing the order of the bits in the
  1155      * two's complement binary representation of the specified {@code long}
  1156      * value.
  1157      *
  1158      * @return the value obtained by reversing order of the bits in the
  1159      *     specified {@code long} value.
  1160      * @since 1.5
  1161      */
  1162     public static long reverse(long i) {
  1163         // HD, Figure 7-1
  1164         i = (i & 0x5555555555555555L) << 1 | (i >>> 1) & 0x5555555555555555L;
  1165         i = (i & 0x3333333333333333L) << 2 | (i >>> 2) & 0x3333333333333333L;
  1166         i = (i & 0x0f0f0f0f0f0f0f0fL) << 4 | (i >>> 4) & 0x0f0f0f0f0f0f0f0fL;
  1167         i = (i & 0x00ff00ff00ff00ffL) << 8 | (i >>> 8) & 0x00ff00ff00ff00ffL;
  1168         i = (i << 48) | ((i & 0xffff0000L) << 16) |
  1169             ((i >>> 16) & 0xffff0000L) | (i >>> 48);
  1170         return i;
  1171     }
  1172 
  1173     /**
  1174      * Returns the signum function of the specified {@code long} value.  (The
  1175      * return value is -1 if the specified value is negative; 0 if the
  1176      * specified value is zero; and 1 if the specified value is positive.)
  1177      *
  1178      * @return the signum function of the specified {@code long} value.
  1179      * @since 1.5
  1180      */
  1181     public static int signum(long i) {
  1182         // HD, Section 2-7
  1183         return (int) ((i >> 63) | (-i >>> 63));
  1184     }
  1185 
  1186     /**
  1187      * Returns the value obtained by reversing the order of the bytes in the
  1188      * two's complement representation of the specified {@code long} value.
  1189      *
  1190      * @return the value obtained by reversing the bytes in the specified
  1191      *     {@code long} value.
  1192      * @since 1.5
  1193      */
  1194     public static long reverseBytes(long i) {
  1195         i = (i & 0x00ff00ff00ff00ffL) << 8 | (i >>> 8) & 0x00ff00ff00ff00ffL;
  1196         return (i << 48) | ((i & 0xffff0000L) << 16) |
  1197             ((i >>> 16) & 0xffff0000L) | (i >>> 48);
  1198     }
  1199 
  1200     /** use serialVersionUID from JDK 1.0.2 for interoperability */
  1201     private static final long serialVersionUID = 4290774380558885855L;
  1202 }