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   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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   5  * This code is free software; you can redistribute it and/or modify it
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   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
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  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
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  23  * questions.
  24  */
  25 
  26 package java.lang;
  27 
  28 import jdk.internal.HotSpotIntrinsicCandidate;
  29 
  30 /**
  31  * The {@code Short} class wraps a value of primitive type {@code
  32  * short} in an object.  An object of type {@code Short} contains a
  33  * single field whose type is {@code short}.
  34  *
  35  * <p>In addition, this class provides several methods for converting
  36  * a {@code short} to a {@code String} and a {@code String} to a
  37  * {@code short}, as well as other constants and methods useful when
  38  * dealing with a {@code short}.
  39  *
  40  * @author  Nakul Saraiya
  41  * @author  Joseph D. Darcy
  42  * @see     java.lang.Number
  43  * @since   1.1
  44  */
  45 public final class Short extends Number implements Comparable<Short> {
  46 
  47     /**
  48      * A constant holding the minimum value a {@code short} can
  49      * have, -2<sup>15</sup>.
  50      */
  51     public static final short   MIN_VALUE = -32768;
  52 
  53     /**
  54      * A constant holding the maximum value a {@code short} can
  55      * have, 2<sup>15</sup>-1.
  56      */
  57     public static final short   MAX_VALUE = 32767;
  58 
  59     /**
  60      * The {@code Class} instance representing the primitive type
  61      * {@code short}.
  62      */
  63     @SuppressWarnings("unchecked")
  64     public static final Class<Short>    TYPE = (Class<Short>) Class.getPrimitiveClass("short");
  65 
  66     /**
  67      * Returns a new {@code String} object representing the
  68      * specified {@code short}. The radix is assumed to be 10.
  69      *
  70      * @param s the {@code short} to be converted
  71      * @return the string representation of the specified {@code short}
  72      * @see java.lang.Integer#toString(int)
  73      */
  74     public static String toString(short s) {
  75         return Integer.toString((int)s, 10);
  76     }
  77 
  78     /**
  79      * Parses the string argument as a signed {@code short} in the
  80      * radix specified by the second argument. The characters in the
  81      * string must all be digits, of the specified radix (as
  82      * determined by whether {@link java.lang.Character#digit(char,
  83      * int)} returns a nonnegative value) except that the first
  84      * character may be an ASCII minus sign {@code '-'}
  85      * ({@code '\u005Cu002D'}) to indicate a negative value or an
  86      * ASCII plus sign {@code '+'} ({@code '\u005Cu002B'}) to
  87      * indicate a positive value.  The resulting {@code short} value
  88      * is returned.
  89      *
  90      * <p>An exception of type {@code NumberFormatException} is
  91      * thrown if any of the following situations occurs:
  92      * <ul>
  93      * <li> The first argument is {@code null} or is a string of
  94      * length zero.
  95      *
  96      * <li> The radix is either smaller than {@link
  97      * java.lang.Character#MIN_RADIX} or larger than {@link
  98      * java.lang.Character#MAX_RADIX}.
  99      *
 100      * <li> Any character of the string is not a digit of the
 101      * specified radix, except that the first character may be a minus
 102      * sign {@code '-'} ({@code '\u005Cu002D'}) or plus sign
 103      * {@code '+'} ({@code '\u005Cu002B'}) provided that the
 104      * string is longer than length 1.
 105      *
 106      * <li> The value represented by the string is not a value of type
 107      * {@code short}.
 108      * </ul>
 109      *
 110      * @param s         the {@code String} containing the
 111      *                  {@code short} representation to be parsed
 112      * @param radix     the radix to be used while parsing {@code s}
 113      * @return          the {@code short} represented by the string
 114      *                  argument in the specified radix.
 115      * @throws          NumberFormatException If the {@code String}
 116      *                  does not contain a parsable {@code short}.
 117      */
 118     public static short parseShort(String s, int radix)
 119         throws NumberFormatException {
 120         int i = Integer.parseInt(s, radix);
 121         if (i < MIN_VALUE || i > MAX_VALUE)
 122             throw new NumberFormatException(
 123                 "Value out of range. Value:\"" + s + "\" Radix:" + radix);
 124         return (short)i;
 125     }
 126 
 127     /**
 128      * Parses the string argument as a signed decimal {@code
 129      * short}. The characters in the string must all be decimal
 130      * digits, except that the first character may be an ASCII minus
 131      * sign {@code '-'} ({@code '\u005Cu002D'}) to indicate a
 132      * negative value or an ASCII plus sign {@code '+'}
 133      * ({@code '\u005Cu002B'}) to indicate a positive value.  The
 134      * resulting {@code short} value is returned, exactly as if the
 135      * argument and the radix 10 were given as arguments to the {@link
 136      * #parseShort(java.lang.String, int)} method.
 137      *
 138      * @param s a {@code String} containing the {@code short}
 139      *          representation to be parsed
 140      * @return  the {@code short} value represented by the
 141      *          argument in decimal.
 142      * @throws  NumberFormatException If the string does not
 143      *          contain a parsable {@code short}.
 144      */
 145     public static short parseShort(String s) throws NumberFormatException {
 146         return parseShort(s, 10);
 147     }
 148 
 149     /**
 150      * Returns a {@code Short} object holding the value
 151      * extracted from the specified {@code String} when parsed
 152      * with the radix given by the second argument. The first argument
 153      * is interpreted as representing a signed {@code short} in
 154      * the radix specified by the second argument, exactly as if the
 155      * argument were given to the {@link #parseShort(java.lang.String,
 156      * int)} method. The result is a {@code Short} object that
 157      * represents the {@code short} value specified by the string.
 158      *
 159      * <p>In other words, this method returns a {@code Short} object
 160      * equal to the value of:
 161      *
 162      * <blockquote>
 163      *  {@code new Short(Short.parseShort(s, radix))}
 164      * </blockquote>
 165      *
 166      * @param s         the string to be parsed
 167      * @param radix     the radix to be used in interpreting {@code s}
 168      * @return          a {@code Short} object holding the value
 169      *                  represented by the string argument in the
 170      *                  specified radix.
 171      * @throws          NumberFormatException If the {@code String} does
 172      *                  not contain a parsable {@code short}.
 173      */
 174     public static Short valueOf(String s, int radix)
 175         throws NumberFormatException {
 176         return valueOf(parseShort(s, radix));
 177     }
 178 
 179     /**
 180      * Returns a {@code Short} object holding the
 181      * value given by the specified {@code String}. The argument
 182      * is interpreted as representing a signed decimal
 183      * {@code short}, exactly as if the argument were given to
 184      * the {@link #parseShort(java.lang.String)} method. The result is
 185      * a {@code Short} object that represents the
 186      * {@code short} value specified by the string.
 187      *
 188      * <p>In other words, this method returns a {@code Short} object
 189      * equal to the value of:
 190      *
 191      * <blockquote>
 192      *  {@code new Short(Short.parseShort(s))}
 193      * </blockquote>
 194      *
 195      * @param s the string to be parsed
 196      * @return  a {@code Short} object holding the value
 197      *          represented by the string argument
 198      * @throws  NumberFormatException If the {@code String} does
 199      *          not contain a parsable {@code short}.
 200      */
 201     public static Short valueOf(String s) throws NumberFormatException {
 202         return valueOf(s, 10);
 203     }
 204 
 205     private static class ShortCache {
 206         private ShortCache(){}
 207 
 208         static final Short cache[] = new Short[-(-128) + 127 + 1];
 209 
 210         static {
 211             for(int i = 0; i < cache.length; i++)
 212                 cache[i] = new Short((short)(i - 128));
 213         }
 214     }
 215 
 216     /**
 217      * Returns a {@code Short} instance representing the specified
 218      * {@code short} value.
 219      * If a new {@code Short} instance is not required, this method
 220      * should generally be used in preference to the constructor
 221      * {@link #Short(short)}, as this method is likely to yield
 222      * significantly better space and time performance by caching
 223      * frequently requested values.
 224      *
 225      * This method will always cache values in the range -128 to 127,
 226      * inclusive, and may cache other values outside of this range.
 227      *
 228      * @param  s a short value.
 229      * @return a {@code Short} instance representing {@code s}.
 230      * @since  1.5
 231      */
 232     @HotSpotIntrinsicCandidate
 233     public static Short valueOf(short s) {
 234         final int offset = 128;
 235         int sAsInt = s;
 236         if (sAsInt >= -128 && sAsInt <= 127) { // must cache
 237             return ShortCache.cache[sAsInt + offset];
 238         }
 239         return new Short(s);
 240     }
 241 
 242     /**
 243      * Decodes a {@code String} into a {@code Short}.
 244      * Accepts decimal, hexadecimal, and octal numbers given by
 245      * the following grammar:
 246      *
 247      * <blockquote>
 248      * <dl>
 249      * <dt><i>DecodableString:</i>
 250      * <dd><i>Sign<sub>opt</sub> DecimalNumeral</i>
 251      * <dd><i>Sign<sub>opt</sub></i> {@code 0x} <i>HexDigits</i>
 252      * <dd><i>Sign<sub>opt</sub></i> {@code 0X} <i>HexDigits</i>
 253      * <dd><i>Sign<sub>opt</sub></i> {@code #} <i>HexDigits</i>
 254      * <dd><i>Sign<sub>opt</sub></i> {@code 0} <i>OctalDigits</i>
 255      *
 256      * <dt><i>Sign:</i>
 257      * <dd>{@code -}
 258      * <dd>{@code +}
 259      * </dl>
 260      * </blockquote>
 261      *
 262      * <i>DecimalNumeral</i>, <i>HexDigits</i>, and <i>OctalDigits</i>
 263      * are as defined in section 3.10.1 of
 264      * <cite>The Java&trade; Language Specification</cite>,
 265      * except that underscores are not accepted between digits.
 266      *
 267      * <p>The sequence of characters following an optional
 268      * sign and/or radix specifier ("{@code 0x}", "{@code 0X}",
 269      * "{@code #}", or leading zero) is parsed as by the {@code
 270      * Short.parseShort} method with the indicated radix (10, 16, or
 271      * 8).  This sequence of characters must represent a positive
 272      * value or a {@link NumberFormatException} will be thrown.  The
 273      * result is negated if first character of the specified {@code
 274      * String} is the minus sign.  No whitespace characters are
 275      * permitted in the {@code String}.
 276      *
 277      * @param     nm the {@code String} to decode.
 278      * @return    a {@code Short} object holding the {@code short}
 279      *            value represented by {@code nm}
 280      * @throws    NumberFormatException  if the {@code String} does not
 281      *            contain a parsable {@code short}.
 282      * @see java.lang.Short#parseShort(java.lang.String, int)
 283      */
 284     public static Short decode(String nm) throws NumberFormatException {
 285         int i = Integer.decode(nm);
 286         if (i < MIN_VALUE || i > MAX_VALUE)
 287             throw new NumberFormatException(
 288                     "Value " + i + " out of range from input " + nm);
 289         return valueOf((short)i);
 290     }
 291 
 292     /**
 293      * The value of the {@code Short}.
 294      *
 295      * @serial
 296      */
 297     private final short value;
 298 
 299     /**
 300      * Constructs a newly allocated {@code Short} object that
 301      * represents the specified {@code short} value.
 302      *
 303      * @param value     the value to be represented by the
 304      *                  {@code Short}.
 305      */
 306     public Short(short value) {
 307         this.value = value;
 308     }
 309 
 310     /**
 311      * Constructs a newly allocated {@code Short} object that
 312      * represents the {@code short} value indicated by the
 313      * {@code String} parameter. The string is converted to a
 314      * {@code short} value in exactly the manner used by the
 315      * {@code parseShort} method for radix 10.
 316      *
 317      * @param s the {@code String} to be converted to a
 318      *          {@code Short}
 319      * @throws  NumberFormatException If the {@code String}
 320      *          does not contain a parsable {@code short}.
 321      * @see     java.lang.Short#parseShort(java.lang.String, int)
 322      */
 323     public Short(String s) throws NumberFormatException {
 324         this.value = parseShort(s, 10);
 325     }
 326 
 327     /**
 328      * Returns the value of this {@code Short} as a {@code byte} after
 329      * a narrowing primitive conversion.
 330      * @jls 5.1.3 Narrowing Primitive Conversions
 331      */
 332     public byte byteValue() {
 333         return (byte)value;
 334     }
 335 
 336     /**
 337      * Returns the value of this {@code Short} as a
 338      * {@code short}.
 339      */
 340     @HotSpotIntrinsicCandidate
 341     public short shortValue() {
 342         return value;
 343     }
 344 
 345     /**
 346      * Returns the value of this {@code Short} as an {@code int} after
 347      * a widening primitive conversion.
 348      * @jls 5.1.2 Widening Primitive Conversions
 349      */
 350     public int intValue() {
 351         return (int)value;
 352     }
 353 
 354     /**
 355      * Returns the value of this {@code Short} as a {@code long} after
 356      * a widening primitive conversion.
 357      * @jls 5.1.2 Widening Primitive Conversions
 358      */
 359     public long longValue() {
 360         return (long)value;
 361     }
 362 
 363     /**
 364      * Returns the value of this {@code Short} as a {@code float}
 365      * after a widening primitive conversion.
 366      * @jls 5.1.2 Widening Primitive Conversions
 367      */
 368     public float floatValue() {
 369         return (float)value;
 370     }
 371 
 372     /**
 373      * Returns the value of this {@code Short} as a {@code double}
 374      * after a widening primitive conversion.
 375      * @jls 5.1.2 Widening Primitive Conversions
 376      */
 377     public double doubleValue() {
 378         return (double)value;
 379     }
 380 
 381     /**
 382      * Returns a {@code String} object representing this
 383      * {@code Short}'s value.  The value is converted to signed
 384      * decimal representation and returned as a string, exactly as if
 385      * the {@code short} value were given as an argument to the
 386      * {@link java.lang.Short#toString(short)} method.
 387      *
 388      * @return  a string representation of the value of this object in
 389      *          base&nbsp;10.
 390      */
 391     public String toString() {
 392         return Integer.toString((int)value);
 393     }
 394 
 395     /**
 396      * Returns a hash code for this {@code Short}; equal to the result
 397      * of invoking {@code intValue()}.
 398      *
 399      * @return a hash code value for this {@code Short}
 400      */
 401     @Override
 402     public int hashCode() {
 403         return Short.hashCode(value);
 404     }
 405 
 406     /**
 407      * Returns a hash code for a {@code short} value; compatible with
 408      * {@code Short.hashCode()}.
 409      *
 410      * @param value the value to hash
 411      * @return a hash code value for a {@code short} value.
 412      * @since 1.8
 413      */
 414     public static int hashCode(short value) {
 415         return (int)value;
 416     }
 417 
 418     /**
 419      * Compares this object to the specified object.  The result is
 420      * {@code true} if and only if the argument is not
 421      * {@code null} and is a {@code Short} object that
 422      * contains the same {@code short} value as this object.
 423      *
 424      * @param obj       the object to compare with
 425      * @return          {@code true} if the objects are the same;
 426      *                  {@code false} otherwise.
 427      */
 428     public boolean equals(Object obj) {
 429         if (obj instanceof Short) {
 430             return value == ((Short)obj).shortValue();
 431         }
 432         return false;
 433     }
 434 
 435     /**
 436      * Compares two {@code Short} objects numerically.
 437      *
 438      * @param   anotherShort   the {@code Short} to be compared.
 439      * @return  the value {@code 0} if this {@code Short} is
 440      *          equal to the argument {@code Short}; a value less than
 441      *          {@code 0} if this {@code Short} is numerically less
 442      *          than the argument {@code Short}; and a value greater than
 443      *           {@code 0} if this {@code Short} is numerically
 444      *           greater than the argument {@code Short} (signed
 445      *           comparison).
 446      * @since   1.2
 447      */
 448     public int compareTo(Short anotherShort) {
 449         return compare(this.value, anotherShort.value);
 450     }
 451 
 452     /**
 453      * Compares two {@code short} values numerically.
 454      * The value returned is identical to what would be returned by:
 455      * <pre>
 456      *    Short.valueOf(x).compareTo(Short.valueOf(y))
 457      * </pre>
 458      *
 459      * @param  x the first {@code short} to compare
 460      * @param  y the second {@code short} to compare
 461      * @return the value {@code 0} if {@code x == y};
 462      *         a value less than {@code 0} if {@code x < y}; and
 463      *         a value greater than {@code 0} if {@code x > y}
 464      * @since 1.7
 465      */
 466     public static int compare(short x, short y) {
 467         return x - y;
 468     }
 469 
 470     /**
 471      * Compares two {@code short} values numerically treating the values
 472      * as unsigned.
 473      *
 474      * @param  x the first {@code short} to compare
 475      * @param  y the second {@code short} to compare
 476      * @return the value {@code 0} if {@code x == y}; a value less
 477      *         than {@code 0} if {@code x < y} as unsigned values; and
 478      *         a value greater than {@code 0} if {@code x > y} as
 479      *         unsigned values
 480      * @since 9
 481      */
 482     public static int compareUnsigned(short x, short y) {
 483         return Short.toUnsignedInt(x) - Short.toUnsignedInt(y);
 484     }
 485 
 486     /**
 487      * The number of bits used to represent a {@code short} value in two's
 488      * complement binary form.
 489      * @since 1.5
 490      */
 491     public static final int SIZE = 16;
 492 
 493     /**
 494      * The number of bytes used to represent a {@code short} value in two's
 495      * complement binary form.
 496      *
 497      * @since 1.8
 498      */
 499     public static final int BYTES = SIZE / Byte.SIZE;
 500 
 501     /**
 502      * Returns the value obtained by reversing the order of the bytes in the
 503      * two's complement representation of the specified {@code short} value.
 504      *
 505      * @param i the value whose bytes are to be reversed
 506      * @return the value obtained by reversing (or, equivalently, swapping)
 507      *     the bytes in the specified {@code short} value.
 508      * @since 1.5
 509      */
 510     @HotSpotIntrinsicCandidate
 511     public static short reverseBytes(short i) {
 512         return (short) (((i & 0xFF00) >> 8) | (i << 8));
 513     }
 514 
 515 
 516     /**
 517      * Converts the argument to an {@code int} by an unsigned
 518      * conversion.  In an unsigned conversion to an {@code int}, the
 519      * high-order 16 bits of the {@code int} are zero and the
 520      * low-order 16 bits are equal to the bits of the {@code short} argument.
 521      *
 522      * Consequently, zero and positive {@code short} values are mapped
 523      * to a numerically equal {@code int} value and negative {@code
 524      * short} values are mapped to an {@code int} value equal to the
 525      * input plus 2<sup>16</sup>.
 526      *
 527      * @param  x the value to convert to an unsigned {@code int}
 528      * @return the argument converted to {@code int} by an unsigned
 529      *         conversion
 530      * @since 1.8
 531      */
 532     public static int toUnsignedInt(short x) {
 533         return ((int) x) & 0xffff;
 534     }
 535 
 536     /**
 537      * Converts the argument to a {@code long} by an unsigned
 538      * conversion.  In an unsigned conversion to a {@code long}, the
 539      * high-order 48 bits of the {@code long} are zero and the
 540      * low-order 16 bits are equal to the bits of the {@code short} argument.
 541      *
 542      * Consequently, zero and positive {@code short} values are mapped
 543      * to a numerically equal {@code long} value and negative {@code
 544      * short} values are mapped to a {@code long} value equal to the
 545      * input plus 2<sup>16</sup>.
 546      *
 547      * @param  x the value to convert to an unsigned {@code long}
 548      * @return the argument converted to {@code long} by an unsigned
 549      *         conversion
 550      * @since 1.8
 551      */
 552     public static long toUnsignedLong(short x) {
 553         return ((long) x) & 0xffffL;
 554     }
 555 
 556     /** use serialVersionUID from JDK 1.1. for interoperability */
 557     private static final long serialVersionUID = 7515723908773894738L;
 558 }