emul/src/main/java/java/lang/Float.java
author Jaroslav Tulach <jaroslav.tulach@apidesign.org>
Sun, 18 Nov 2012 19:54:40 +0100
branchjavap
changeset 187 391a5d25c0e1
parent 181 f426de5dc7f6
permissions -rw-r--r--
toString on floats and doubles should end with .0
     1 /*
     2  * Copyright (c) 1994, 2010, 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 Float} class wraps a value of primitive type
    32  * {@code float} in an object. An object of type
    33  * {@code Float} contains a single field whose type is
    34  * {@code float}.
    35  *
    36  * <p>In addition, this class provides several methods for converting a
    37  * {@code float} to a {@code String} and a
    38  * {@code String} to a {@code float}, as well as other
    39  * constants and methods useful when dealing with a
    40  * {@code float}.
    41  *
    42  * @author  Lee Boynton
    43  * @author  Arthur van Hoff
    44  * @author  Joseph D. Darcy
    45  * @since JDK1.0
    46  */
    47 public final class Float extends Number implements Comparable<Float> {
    48     /**
    49      * A constant holding the positive infinity of type
    50      * {@code float}. It is equal to the value returned by
    51      * {@code Float.intBitsToFloat(0x7f800000)}.
    52      */
    53     public static final float POSITIVE_INFINITY = 1.0f / 0.0f;
    54 
    55     /**
    56      * A constant holding the negative infinity of type
    57      * {@code float}. It is equal to the value returned by
    58      * {@code Float.intBitsToFloat(0xff800000)}.
    59      */
    60     public static final float NEGATIVE_INFINITY = -1.0f / 0.0f;
    61 
    62     /**
    63      * A constant holding a Not-a-Number (NaN) value of type
    64      * {@code float}.  It is equivalent to the value returned by
    65      * {@code Float.intBitsToFloat(0x7fc00000)}.
    66      */
    67     public static final float NaN = 0.0f / 0.0f;
    68 
    69     /**
    70      * A constant holding the largest positive finite value of type
    71      * {@code float}, (2-2<sup>-23</sup>)&middot;2<sup>127</sup>.
    72      * It is equal to the hexadecimal floating-point literal
    73      * {@code 0x1.fffffeP+127f} and also equal to
    74      * {@code Float.intBitsToFloat(0x7f7fffff)}.
    75      */
    76     public static final float MAX_VALUE = 0x1.fffffeP+127f; // 3.4028235e+38f
    77 
    78     /**
    79      * A constant holding the smallest positive normal value of type
    80      * {@code float}, 2<sup>-126</sup>.  It is equal to the
    81      * hexadecimal floating-point literal {@code 0x1.0p-126f} and also
    82      * equal to {@code Float.intBitsToFloat(0x00800000)}.
    83      *
    84      * @since 1.6
    85      */
    86     public static final float MIN_NORMAL = 0x1.0p-126f; // 1.17549435E-38f
    87 
    88     /**
    89      * A constant holding the smallest positive nonzero value of type
    90      * {@code float}, 2<sup>-149</sup>. It is equal to the
    91      * hexadecimal floating-point literal {@code 0x0.000002P-126f}
    92      * and also equal to {@code Float.intBitsToFloat(0x1)}.
    93      */
    94     public static final float MIN_VALUE = 0x0.000002P-126f; // 1.4e-45f
    95 
    96     /**
    97      * Maximum exponent a finite {@code float} variable may have.  It
    98      * is equal to the value returned by {@code
    99      * Math.getExponent(Float.MAX_VALUE)}.
   100      *
   101      * @since 1.6
   102      */
   103     public static final int MAX_EXPONENT = 127;
   104 
   105     /**
   106      * Minimum exponent a normalized {@code float} variable may have.
   107      * It is equal to the value returned by {@code
   108      * Math.getExponent(Float.MIN_NORMAL)}.
   109      *
   110      * @since 1.6
   111      */
   112     public static final int MIN_EXPONENT = -126;
   113 
   114     /**
   115      * The number of bits used to represent a {@code float} value.
   116      *
   117      * @since 1.5
   118      */
   119     public static final int SIZE = 32;
   120 
   121     /**
   122      * The {@code Class} instance representing the primitive type
   123      * {@code float}.
   124      *
   125      * @since JDK1.1
   126      */
   127     public static final Class<Float> TYPE = Class.getPrimitiveClass("float");
   128 
   129     /**
   130      * Returns a string representation of the {@code float}
   131      * argument. All characters mentioned below are ASCII characters.
   132      * <ul>
   133      * <li>If the argument is NaN, the result is the string
   134      * "{@code NaN}".
   135      * <li>Otherwise, the result is a string that represents the sign and
   136      *     magnitude (absolute value) of the argument. If the sign is
   137      *     negative, the first character of the result is
   138      *     '{@code -}' (<code>'&#92;u002D'</code>); if the sign is
   139      *     positive, no sign character appears in the result. As for
   140      *     the magnitude <i>m</i>:
   141      * <ul>
   142      * <li>If <i>m</i> is infinity, it is represented by the characters
   143      *     {@code "Infinity"}; thus, positive infinity produces
   144      *     the result {@code "Infinity"} and negative infinity
   145      *     produces the result {@code "-Infinity"}.
   146      * <li>If <i>m</i> is zero, it is represented by the characters
   147      *     {@code "0.0"}; thus, negative zero produces the result
   148      *     {@code "-0.0"} and positive zero produces the result
   149      *     {@code "0.0"}.
   150      * <li> If <i>m</i> is greater than or equal to 10<sup>-3</sup> but
   151      *      less than 10<sup>7</sup>, then it is represented as the
   152      *      integer part of <i>m</i>, in decimal form with no leading
   153      *      zeroes, followed by '{@code .}'
   154      *      (<code>'&#92;u002E'</code>), followed by one or more
   155      *      decimal digits representing the fractional part of
   156      *      <i>m</i>.
   157      * <li> If <i>m</i> is less than 10<sup>-3</sup> or greater than or
   158      *      equal to 10<sup>7</sup>, then it is represented in
   159      *      so-called "computerized scientific notation." Let <i>n</i>
   160      *      be the unique integer such that 10<sup><i>n</i> </sup>&le;
   161      *      <i>m</i> {@literal <} 10<sup><i>n</i>+1</sup>; then let <i>a</i>
   162      *      be the mathematically exact quotient of <i>m</i> and
   163      *      10<sup><i>n</i></sup> so that 1 &le; <i>a</i> {@literal <} 10.
   164      *      The magnitude is then represented as the integer part of
   165      *      <i>a</i>, as a single decimal digit, followed by
   166      *      '{@code .}' (<code>'&#92;u002E'</code>), followed by
   167      *      decimal digits representing the fractional part of
   168      *      <i>a</i>, followed by the letter '{@code E}'
   169      *      (<code>'&#92;u0045'</code>), followed by a representation
   170      *      of <i>n</i> as a decimal integer, as produced by the
   171      *      method {@link java.lang.Integer#toString(int)}.
   172      *
   173      * </ul>
   174      * </ul>
   175      * How many digits must be printed for the fractional part of
   176      * <i>m</i> or <i>a</i>? There must be at least one digit
   177      * to represent the fractional part, and beyond that as many, but
   178      * only as many, more digits as are needed to uniquely distinguish
   179      * the argument value from adjacent values of type
   180      * {@code float}. That is, suppose that <i>x</i> is the
   181      * exact mathematical value represented by the decimal
   182      * representation produced by this method for a finite nonzero
   183      * argument <i>f</i>. Then <i>f</i> must be the {@code float}
   184      * value nearest to <i>x</i>; or, if two {@code float} values are
   185      * equally close to <i>x</i>, then <i>f</i> must be one of
   186      * them and the least significant bit of the significand of
   187      * <i>f</i> must be {@code 0}.
   188      *
   189      * <p>To create localized string representations of a floating-point
   190      * value, use subclasses of {@link java.text.NumberFormat}.
   191      *
   192      * @param   f   the float to be converted.
   193      * @return a string representation of the argument.
   194      */
   195     public static String toString(float f) {
   196         return Double.toString(f);
   197     }
   198 
   199     /**
   200      * Returns a hexadecimal string representation of the
   201      * {@code float} argument. All characters mentioned below are
   202      * ASCII characters.
   203      *
   204      * <ul>
   205      * <li>If the argument is NaN, the result is the string
   206      *     "{@code NaN}".
   207      * <li>Otherwise, the result is a string that represents the sign and
   208      * magnitude (absolute value) of the argument. If the sign is negative,
   209      * the first character of the result is '{@code -}'
   210      * (<code>'&#92;u002D'</code>); if the sign is positive, no sign character
   211      * appears in the result. As for the magnitude <i>m</i>:
   212      *
   213      * <ul>
   214      * <li>If <i>m</i> is infinity, it is represented by the string
   215      * {@code "Infinity"}; thus, positive infinity produces the
   216      * result {@code "Infinity"} and negative infinity produces
   217      * the result {@code "-Infinity"}.
   218      *
   219      * <li>If <i>m</i> is zero, it is represented by the string
   220      * {@code "0x0.0p0"}; thus, negative zero produces the result
   221      * {@code "-0x0.0p0"} and positive zero produces the result
   222      * {@code "0x0.0p0"}.
   223      *
   224      * <li>If <i>m</i> is a {@code float} value with a
   225      * normalized representation, substrings are used to represent the
   226      * significand and exponent fields.  The significand is
   227      * represented by the characters {@code "0x1."}
   228      * followed by a lowercase hexadecimal representation of the rest
   229      * of the significand as a fraction.  Trailing zeros in the
   230      * hexadecimal representation are removed unless all the digits
   231      * are zero, in which case a single zero is used. Next, the
   232      * exponent is represented by {@code "p"} followed
   233      * by a decimal string of the unbiased exponent as if produced by
   234      * a call to {@link Integer#toString(int) Integer.toString} on the
   235      * exponent value.
   236      *
   237      * <li>If <i>m</i> is a {@code float} value with a subnormal
   238      * representation, the significand is represented by the
   239      * characters {@code "0x0."} followed by a
   240      * hexadecimal representation of the rest of the significand as a
   241      * fraction.  Trailing zeros in the hexadecimal representation are
   242      * removed. Next, the exponent is represented by
   243      * {@code "p-126"}.  Note that there must be at
   244      * least one nonzero digit in a subnormal significand.
   245      *
   246      * </ul>
   247      *
   248      * </ul>
   249      *
   250      * <table border>
   251      * <caption><h3>Examples</h3></caption>
   252      * <tr><th>Floating-point Value</th><th>Hexadecimal String</th>
   253      * <tr><td>{@code 1.0}</td> <td>{@code 0x1.0p0}</td>
   254      * <tr><td>{@code -1.0}</td>        <td>{@code -0x1.0p0}</td>
   255      * <tr><td>{@code 2.0}</td> <td>{@code 0x1.0p1}</td>
   256      * <tr><td>{@code 3.0}</td> <td>{@code 0x1.8p1}</td>
   257      * <tr><td>{@code 0.5}</td> <td>{@code 0x1.0p-1}</td>
   258      * <tr><td>{@code 0.25}</td>        <td>{@code 0x1.0p-2}</td>
   259      * <tr><td>{@code Float.MAX_VALUE}</td>
   260      *     <td>{@code 0x1.fffffep127}</td>
   261      * <tr><td>{@code Minimum Normal Value}</td>
   262      *     <td>{@code 0x1.0p-126}</td>
   263      * <tr><td>{@code Maximum Subnormal Value}</td>
   264      *     <td>{@code 0x0.fffffep-126}</td>
   265      * <tr><td>{@code Float.MIN_VALUE}</td>
   266      *     <td>{@code 0x0.000002p-126}</td>
   267      * </table>
   268      * @param   f   the {@code float} to be converted.
   269      * @return a hex string representation of the argument.
   270      * @since 1.5
   271      * @author Joseph D. Darcy
   272      */
   273     public static String toHexString(float f) {
   274         throw new UnsupportedOperationException();
   275 //        if (Math.abs(f) < FloatConsts.MIN_NORMAL
   276 //            &&  f != 0.0f ) {// float subnormal
   277 //            // Adjust exponent to create subnormal double, then
   278 //            // replace subnormal double exponent with subnormal float
   279 //            // exponent
   280 //            String s = Double.toHexString(FpUtils.scalb((double)f,
   281 //                                                        /* -1022+126 */
   282 //                                                        DoubleConsts.MIN_EXPONENT-
   283 //                                                        FloatConsts.MIN_EXPONENT));
   284 //            return s.replaceFirst("p-1022$", "p-126");
   285 //        }
   286 //        else // double string will be the same as float string
   287 //            return Double.toHexString(f);
   288     }
   289 
   290     /**
   291      * Returns a {@code Float} object holding the
   292      * {@code float} value represented by the argument string
   293      * {@code s}.
   294      *
   295      * <p>If {@code s} is {@code null}, then a
   296      * {@code NullPointerException} is thrown.
   297      *
   298      * <p>Leading and trailing whitespace characters in {@code s}
   299      * are ignored.  Whitespace is removed as if by the {@link
   300      * String#trim} method; that is, both ASCII space and control
   301      * characters are removed. The rest of {@code s} should
   302      * constitute a <i>FloatValue</i> as described by the lexical
   303      * syntax rules:
   304      *
   305      * <blockquote>
   306      * <dl>
   307      * <dt><i>FloatValue:</i>
   308      * <dd><i>Sign<sub>opt</sub></i> {@code NaN}
   309      * <dd><i>Sign<sub>opt</sub></i> {@code Infinity}
   310      * <dd><i>Sign<sub>opt</sub> FloatingPointLiteral</i>
   311      * <dd><i>Sign<sub>opt</sub> HexFloatingPointLiteral</i>
   312      * <dd><i>SignedInteger</i>
   313      * </dl>
   314      *
   315      * <p>
   316      *
   317      * <dl>
   318      * <dt><i>HexFloatingPointLiteral</i>:
   319      * <dd> <i>HexSignificand BinaryExponent FloatTypeSuffix<sub>opt</sub></i>
   320      * </dl>
   321      *
   322      * <p>
   323      *
   324      * <dl>
   325      * <dt><i>HexSignificand:</i>
   326      * <dd><i>HexNumeral</i>
   327      * <dd><i>HexNumeral</i> {@code .}
   328      * <dd>{@code 0x} <i>HexDigits<sub>opt</sub>
   329      *     </i>{@code .}<i> HexDigits</i>
   330      * <dd>{@code 0X}<i> HexDigits<sub>opt</sub>
   331      *     </i>{@code .} <i>HexDigits</i>
   332      * </dl>
   333      *
   334      * <p>
   335      *
   336      * <dl>
   337      * <dt><i>BinaryExponent:</i>
   338      * <dd><i>BinaryExponentIndicator SignedInteger</i>
   339      * </dl>
   340      *
   341      * <p>
   342      *
   343      * <dl>
   344      * <dt><i>BinaryExponentIndicator:</i>
   345      * <dd>{@code p}
   346      * <dd>{@code P}
   347      * </dl>
   348      *
   349      * </blockquote>
   350      *
   351      * where <i>Sign</i>, <i>FloatingPointLiteral</i>,
   352      * <i>HexNumeral</i>, <i>HexDigits</i>, <i>SignedInteger</i> and
   353      * <i>FloatTypeSuffix</i> are as defined in the lexical structure
   354      * sections of
   355      * <cite>The Java&trade; Language Specification</cite>,
   356      * except that underscores are not accepted between digits.
   357      * If {@code s} does not have the form of
   358      * a <i>FloatValue</i>, then a {@code NumberFormatException}
   359      * is thrown. Otherwise, {@code s} is regarded as
   360      * representing an exact decimal value in the usual
   361      * "computerized scientific notation" or as an exact
   362      * hexadecimal value; this exact numerical value is then
   363      * conceptually converted to an "infinitely precise"
   364      * binary value that is then rounded to type {@code float}
   365      * by the usual round-to-nearest rule of IEEE 754 floating-point
   366      * arithmetic, which includes preserving the sign of a zero
   367      * value.
   368      *
   369      * Note that the round-to-nearest rule also implies overflow and
   370      * underflow behaviour; if the exact value of {@code s} is large
   371      * enough in magnitude (greater than or equal to ({@link
   372      * #MAX_VALUE} + {@link Math#ulp(float) ulp(MAX_VALUE)}/2),
   373      * rounding to {@code float} will result in an infinity and if the
   374      * exact value of {@code s} is small enough in magnitude (less
   375      * than or equal to {@link #MIN_VALUE}/2), rounding to float will
   376      * result in a zero.
   377      *
   378      * Finally, after rounding a {@code Float} object representing
   379      * this {@code float} value is returned.
   380      *
   381      * <p>To interpret localized string representations of a
   382      * floating-point value, use subclasses of {@link
   383      * java.text.NumberFormat}.
   384      *
   385      * <p>Note that trailing format specifiers, specifiers that
   386      * determine the type of a floating-point literal
   387      * ({@code 1.0f} is a {@code float} value;
   388      * {@code 1.0d} is a {@code double} value), do
   389      * <em>not</em> influence the results of this method.  In other
   390      * words, the numerical value of the input string is converted
   391      * directly to the target floating-point type.  In general, the
   392      * two-step sequence of conversions, string to {@code double}
   393      * followed by {@code double} to {@code float}, is
   394      * <em>not</em> equivalent to converting a string directly to
   395      * {@code float}.  For example, if first converted to an
   396      * intermediate {@code double} and then to
   397      * {@code float}, the string<br>
   398      * {@code "1.00000017881393421514957253748434595763683319091796875001d"}<br>
   399      * results in the {@code float} value
   400      * {@code 1.0000002f}; if the string is converted directly to
   401      * {@code float}, <code>1.000000<b>1</b>f</code> results.
   402      *
   403      * <p>To avoid calling this method on an invalid string and having
   404      * a {@code NumberFormatException} be thrown, the documentation
   405      * for {@link Double#valueOf Double.valueOf} lists a regular
   406      * expression which can be used to screen the input.
   407      *
   408      * @param   s   the string to be parsed.
   409      * @return  a {@code Float} object holding the value
   410      *          represented by the {@code String} argument.
   411      * @throws  NumberFormatException  if the string does not contain a
   412      *          parsable number.
   413      */
   414     public static Float valueOf(String s) throws NumberFormatException {
   415         throw new UnsupportedOperationException();
   416 //        return new Float(FloatingDecimal.readJavaFormatString(s).floatValue());
   417     }
   418 
   419     /**
   420      * Returns a {@code Float} instance representing the specified
   421      * {@code float} value.
   422      * If a new {@code Float} instance is not required, this method
   423      * should generally be used in preference to the constructor
   424      * {@link #Float(float)}, as this method is likely to yield
   425      * significantly better space and time performance by caching
   426      * frequently requested values.
   427      *
   428      * @param  f a float value.
   429      * @return a {@code Float} instance representing {@code f}.
   430      * @since  1.5
   431      */
   432     public static Float valueOf(float f) {
   433         return new Float(f);
   434     }
   435 
   436     /**
   437      * Returns a new {@code float} initialized to the value
   438      * represented by the specified {@code String}, as performed
   439      * by the {@code valueOf} method of class {@code Float}.
   440      *
   441      * @param  s the string to be parsed.
   442      * @return the {@code float} value represented by the string
   443      *         argument.
   444      * @throws NullPointerException  if the string is null
   445      * @throws NumberFormatException if the string does not contain a
   446      *               parsable {@code float}.
   447      * @see    java.lang.Float#valueOf(String)
   448      * @since 1.2
   449      */
   450     public static float parseFloat(String s) throws NumberFormatException {
   451         throw new UnsupportedOperationException();
   452 //        return FloatingDecimal.readJavaFormatString(s).floatValue();
   453     }
   454 
   455     /**
   456      * Returns {@code true} if the specified number is a
   457      * Not-a-Number (NaN) value, {@code false} otherwise.
   458      *
   459      * @param   v   the value to be tested.
   460      * @return  {@code true} if the argument is NaN;
   461      *          {@code false} otherwise.
   462      */
   463     static public boolean isNaN(float v) {
   464         return (v != v);
   465     }
   466 
   467     /**
   468      * Returns {@code true} if the specified number is infinitely
   469      * large in magnitude, {@code false} otherwise.
   470      *
   471      * @param   v   the value to be tested.
   472      * @return  {@code true} if the argument is positive infinity or
   473      *          negative infinity; {@code false} otherwise.
   474      */
   475     static public boolean isInfinite(float v) {
   476         return (v == POSITIVE_INFINITY) || (v == NEGATIVE_INFINITY);
   477     }
   478 
   479     /**
   480      * The value of the Float.
   481      *
   482      * @serial
   483      */
   484     private final float value;
   485 
   486     /**
   487      * Constructs a newly allocated {@code Float} object that
   488      * represents the primitive {@code float} argument.
   489      *
   490      * @param   value   the value to be represented by the {@code Float}.
   491      */
   492     public Float(float value) {
   493         this.value = value;
   494     }
   495 
   496     /**
   497      * Constructs a newly allocated {@code Float} object that
   498      * represents the argument converted to type {@code float}.
   499      *
   500      * @param   value   the value to be represented by the {@code Float}.
   501      */
   502     public Float(double value) {
   503         this.value = (float)value;
   504     }
   505 
   506     /**
   507      * Constructs a newly allocated {@code Float} object that
   508      * represents the floating-point value of type {@code float}
   509      * represented by the string. The string is converted to a
   510      * {@code float} value as if by the {@code valueOf} method.
   511      *
   512      * @param      s   a string to be converted to a {@code Float}.
   513      * @throws  NumberFormatException  if the string does not contain a
   514      *               parsable number.
   515      * @see        java.lang.Float#valueOf(java.lang.String)
   516      */
   517     public Float(String s) throws NumberFormatException {
   518         // REMIND: this is inefficient
   519         this(valueOf(s).floatValue());
   520     }
   521 
   522     /**
   523      * Returns {@code true} if this {@code Float} value is a
   524      * Not-a-Number (NaN), {@code false} otherwise.
   525      *
   526      * @return  {@code true} if the value represented by this object is
   527      *          NaN; {@code false} otherwise.
   528      */
   529     public boolean isNaN() {
   530         return isNaN(value);
   531     }
   532 
   533     /**
   534      * Returns {@code true} if this {@code Float} value is
   535      * infinitely large in magnitude, {@code false} otherwise.
   536      *
   537      * @return  {@code true} if the value represented by this object is
   538      *          positive infinity or negative infinity;
   539      *          {@code false} otherwise.
   540      */
   541     public boolean isInfinite() {
   542         return isInfinite(value);
   543     }
   544 
   545     /**
   546      * Returns a string representation of this {@code Float} object.
   547      * The primitive {@code float} value represented by this object
   548      * is converted to a {@code String} exactly as if by the method
   549      * {@code toString} of one argument.
   550      *
   551      * @return  a {@code String} representation of this object.
   552      * @see java.lang.Float#toString(float)
   553      */
   554     public String toString() {
   555         return Float.toString(value);
   556     }
   557 
   558     /**
   559      * Returns the value of this {@code Float} as a {@code byte} (by
   560      * casting to a {@code byte}).
   561      *
   562      * @return  the {@code float} value represented by this object
   563      *          converted to type {@code byte}
   564      */
   565     public byte byteValue() {
   566         return (byte)value;
   567     }
   568 
   569     /**
   570      * Returns the value of this {@code Float} as a {@code short} (by
   571      * casting to a {@code short}).
   572      *
   573      * @return  the {@code float} value represented by this object
   574      *          converted to type {@code short}
   575      * @since JDK1.1
   576      */
   577     public short shortValue() {
   578         return (short)value;
   579     }
   580 
   581     /**
   582      * Returns the value of this {@code Float} as an {@code int} (by
   583      * casting to type {@code int}).
   584      *
   585      * @return  the {@code float} value represented by this object
   586      *          converted to type {@code int}
   587      */
   588     public int intValue() {
   589         return (int)value;
   590     }
   591 
   592     /**
   593      * Returns value of this {@code Float} as a {@code long} (by
   594      * casting to type {@code long}).
   595      *
   596      * @return  the {@code float} value represented by this object
   597      *          converted to type {@code long}
   598      */
   599     public long longValue() {
   600         return (long)value;
   601     }
   602 
   603     /**
   604      * Returns the {@code float} value of this {@code Float} object.
   605      *
   606      * @return the {@code float} value represented by this object
   607      */
   608     public float floatValue() {
   609         return value;
   610     }
   611 
   612     /**
   613      * Returns the {@code double} value of this {@code Float} object.
   614      *
   615      * @return the {@code float} value represented by this
   616      *         object is converted to type {@code double} and the
   617      *         result of the conversion is returned.
   618      */
   619     public double doubleValue() {
   620         return (double)value;
   621     }
   622 
   623     /**
   624      * Returns a hash code for this {@code Float} object. The
   625      * result is the integer bit representation, exactly as produced
   626      * by the method {@link #floatToIntBits(float)}, of the primitive
   627      * {@code float} value represented by this {@code Float}
   628      * object.
   629      *
   630      * @return a hash code value for this object.
   631      */
   632     public int hashCode() {
   633         return floatToIntBits(value);
   634     }
   635 
   636     /**
   637 
   638      * Compares this object against the specified object.  The result
   639      * is {@code true} if and only if the argument is not
   640      * {@code null} and is a {@code Float} object that
   641      * represents a {@code float} with the same value as the
   642      * {@code float} represented by this object. For this
   643      * purpose, two {@code float} values are considered to be the
   644      * same if and only if the method {@link #floatToIntBits(float)}
   645      * returns the identical {@code int} value when applied to
   646      * each.
   647      *
   648      * <p>Note that in most cases, for two instances of class
   649      * {@code Float}, {@code f1} and {@code f2}, the value
   650      * of {@code f1.equals(f2)} is {@code true} if and only if
   651      *
   652      * <blockquote><pre>
   653      *   f1.floatValue() == f2.floatValue()
   654      * </pre></blockquote>
   655      *
   656      * <p>also has the value {@code true}. However, there are two exceptions:
   657      * <ul>
   658      * <li>If {@code f1} and {@code f2} both represent
   659      *     {@code Float.NaN}, then the {@code equals} method returns
   660      *     {@code true}, even though {@code Float.NaN==Float.NaN}
   661      *     has the value {@code false}.
   662      * <li>If {@code f1} represents {@code +0.0f} while
   663      *     {@code f2} represents {@code -0.0f}, or vice
   664      *     versa, the {@code equal} test has the value
   665      *     {@code false}, even though {@code 0.0f==-0.0f}
   666      *     has the value {@code true}.
   667      * </ul>
   668      *
   669      * This definition allows hash tables to operate properly.
   670      *
   671      * @param obj the object to be compared
   672      * @return  {@code true} if the objects are the same;
   673      *          {@code false} otherwise.
   674      * @see java.lang.Float#floatToIntBits(float)
   675      */
   676     public boolean equals(Object obj) {
   677         return (obj instanceof Float)
   678                && (floatToIntBits(((Float)obj).value) == floatToIntBits(value));
   679     }
   680 
   681     /**
   682      * Returns a representation of the specified floating-point value
   683      * according to the IEEE 754 floating-point "single format" bit
   684      * layout.
   685      *
   686      * <p>Bit 31 (the bit that is selected by the mask
   687      * {@code 0x80000000}) represents the sign of the floating-point
   688      * number.
   689      * Bits 30-23 (the bits that are selected by the mask
   690      * {@code 0x7f800000}) represent the exponent.
   691      * Bits 22-0 (the bits that are selected by the mask
   692      * {@code 0x007fffff}) represent the significand (sometimes called
   693      * the mantissa) of the floating-point number.
   694      *
   695      * <p>If the argument is positive infinity, the result is
   696      * {@code 0x7f800000}.
   697      *
   698      * <p>If the argument is negative infinity, the result is
   699      * {@code 0xff800000}.
   700      *
   701      * <p>If the argument is NaN, the result is {@code 0x7fc00000}.
   702      *
   703      * <p>In all cases, the result is an integer that, when given to the
   704      * {@link #intBitsToFloat(int)} method, will produce a floating-point
   705      * value the same as the argument to {@code floatToIntBits}
   706      * (except all NaN values are collapsed to a single
   707      * "canonical" NaN value).
   708      *
   709      * @param   value   a floating-point number.
   710      * @return the bits that represent the floating-point number.
   711      */
   712     public static int floatToIntBits(float value) {
   713         throw new UnsupportedOperationException();
   714 //        int result = floatToRawIntBits(value);
   715 //        // Check for NaN based on values of bit fields, maximum
   716 //        // exponent and nonzero significand.
   717 //        if ( ((result & FloatConsts.EXP_BIT_MASK) ==
   718 //              FloatConsts.EXP_BIT_MASK) &&
   719 //             (result & FloatConsts.SIGNIF_BIT_MASK) != 0)
   720 //            result = 0x7fc00000;
   721 //        return result;
   722     }
   723 
   724     /**
   725      * Returns a representation of the specified floating-point value
   726      * according to the IEEE 754 floating-point "single format" bit
   727      * layout, preserving Not-a-Number (NaN) values.
   728      *
   729      * <p>Bit 31 (the bit that is selected by the mask
   730      * {@code 0x80000000}) represents the sign of the floating-point
   731      * number.
   732      * Bits 30-23 (the bits that are selected by the mask
   733      * {@code 0x7f800000}) represent the exponent.
   734      * Bits 22-0 (the bits that are selected by the mask
   735      * {@code 0x007fffff}) represent the significand (sometimes called
   736      * the mantissa) of the floating-point number.
   737      *
   738      * <p>If the argument is positive infinity, the result is
   739      * {@code 0x7f800000}.
   740      *
   741      * <p>If the argument is negative infinity, the result is
   742      * {@code 0xff800000}.
   743      *
   744      * <p>If the argument is NaN, the result is the integer representing
   745      * the actual NaN value.  Unlike the {@code floatToIntBits}
   746      * method, {@code floatToRawIntBits} does not collapse all the
   747      * bit patterns encoding a NaN to a single "canonical"
   748      * NaN value.
   749      *
   750      * <p>In all cases, the result is an integer that, when given to the
   751      * {@link #intBitsToFloat(int)} method, will produce a
   752      * floating-point value the same as the argument to
   753      * {@code floatToRawIntBits}.
   754      *
   755      * @param   value   a floating-point number.
   756      * @return the bits that represent the floating-point number.
   757      * @since 1.3
   758      */
   759     public static native int floatToRawIntBits(float value);
   760 
   761     /**
   762      * Returns the {@code float} value corresponding to a given
   763      * bit representation.
   764      * The argument is considered to be a representation of a
   765      * floating-point value according to the IEEE 754 floating-point
   766      * "single format" bit layout.
   767      *
   768      * <p>If the argument is {@code 0x7f800000}, the result is positive
   769      * infinity.
   770      *
   771      * <p>If the argument is {@code 0xff800000}, the result is negative
   772      * infinity.
   773      *
   774      * <p>If the argument is any value in the range
   775      * {@code 0x7f800001} through {@code 0x7fffffff} or in
   776      * the range {@code 0xff800001} through
   777      * {@code 0xffffffff}, the result is a NaN.  No IEEE 754
   778      * floating-point operation provided by Java can distinguish
   779      * between two NaN values of the same type with different bit
   780      * patterns.  Distinct values of NaN are only distinguishable by
   781      * use of the {@code Float.floatToRawIntBits} method.
   782      *
   783      * <p>In all other cases, let <i>s</i>, <i>e</i>, and <i>m</i> be three
   784      * values that can be computed from the argument:
   785      *
   786      * <blockquote><pre>
   787      * int s = ((bits &gt;&gt; 31) == 0) ? 1 : -1;
   788      * int e = ((bits &gt;&gt; 23) & 0xff);
   789      * int m = (e == 0) ?
   790      *                 (bits & 0x7fffff) &lt;&lt; 1 :
   791      *                 (bits & 0x7fffff) | 0x800000;
   792      * </pre></blockquote>
   793      *
   794      * Then the floating-point result equals the value of the mathematical
   795      * expression <i>s</i>&middot;<i>m</i>&middot;2<sup><i>e</i>-150</sup>.
   796      *
   797      * <p>Note that this method may not be able to return a
   798      * {@code float} NaN with exactly same bit pattern as the
   799      * {@code int} argument.  IEEE 754 distinguishes between two
   800      * kinds of NaNs, quiet NaNs and <i>signaling NaNs</i>.  The
   801      * differences between the two kinds of NaN are generally not
   802      * visible in Java.  Arithmetic operations on signaling NaNs turn
   803      * them into quiet NaNs with a different, but often similar, bit
   804      * pattern.  However, on some processors merely copying a
   805      * signaling NaN also performs that conversion.  In particular,
   806      * copying a signaling NaN to return it to the calling method may
   807      * perform this conversion.  So {@code intBitsToFloat} may
   808      * not be able to return a {@code float} with a signaling NaN
   809      * bit pattern.  Consequently, for some {@code int} values,
   810      * {@code floatToRawIntBits(intBitsToFloat(start))} may
   811      * <i>not</i> equal {@code start}.  Moreover, which
   812      * particular bit patterns represent signaling NaNs is platform
   813      * dependent; although all NaN bit patterns, quiet or signaling,
   814      * must be in the NaN range identified above.
   815      *
   816      * @param   bits   an integer.
   817      * @return  the {@code float} floating-point value with the same bit
   818      *          pattern.
   819      */
   820     @JavaScriptBody(args = "bits",
   821         body = 
   822           "if (bits === 0x7f800000) return Number.POSITIVE_INFINITY;\n"
   823         + "if (bits === 0xff800000) return Number.NEGATIVE_INFINITY;\n"
   824         + "if (bits >= 0x7f800001 && bits <= 0xffffffff) return Number.NaN;\n"
   825         + "var s = ((bits >> 31) == 0) ? 1 : -1;\n"
   826         + "var e = ((bits >> 23) & 0xff);\n"
   827         + "var m = (e == 0) ?\n"
   828         + "  (bits & 0x7fffff) << 1 :\n"
   829         + "  (bits & 0x7fffff) | 0x800000;\n"
   830         + "return s * m * Math.pow(2.0, e - 150);\n"
   831     )
   832     public static native float intBitsToFloat(int bits);
   833 
   834     /**
   835      * Compares two {@code Float} objects numerically.  There are
   836      * two ways in which comparisons performed by this method differ
   837      * from those performed by the Java language numerical comparison
   838      * operators ({@code <, <=, ==, >=, >}) when
   839      * applied to primitive {@code float} values:
   840      *
   841      * <ul><li>
   842      *          {@code Float.NaN} is considered by this method to
   843      *          be equal to itself and greater than all other
   844      *          {@code float} values
   845      *          (including {@code Float.POSITIVE_INFINITY}).
   846      * <li>
   847      *          {@code 0.0f} is considered by this method to be greater
   848      *          than {@code -0.0f}.
   849      * </ul>
   850      *
   851      * This ensures that the <i>natural ordering</i> of {@code Float}
   852      * objects imposed by this method is <i>consistent with equals</i>.
   853      *
   854      * @param   anotherFloat   the {@code Float} to be compared.
   855      * @return  the value {@code 0} if {@code anotherFloat} is
   856      *          numerically equal to this {@code Float}; a value
   857      *          less than {@code 0} if this {@code Float}
   858      *          is numerically less than {@code anotherFloat};
   859      *          and a value greater than {@code 0} if this
   860      *          {@code Float} is numerically greater than
   861      *          {@code anotherFloat}.
   862      *
   863      * @since   1.2
   864      * @see Comparable#compareTo(Object)
   865      */
   866     public int compareTo(Float anotherFloat) {
   867         return Float.compare(value, anotherFloat.value);
   868     }
   869 
   870     /**
   871      * Compares the two specified {@code float} values. The sign
   872      * of the integer value returned is the same as that of the
   873      * integer that would be returned by the call:
   874      * <pre>
   875      *    new Float(f1).compareTo(new Float(f2))
   876      * </pre>
   877      *
   878      * @param   f1        the first {@code float} to compare.
   879      * @param   f2        the second {@code float} to compare.
   880      * @return  the value {@code 0} if {@code f1} is
   881      *          numerically equal to {@code f2}; a value less than
   882      *          {@code 0} if {@code f1} is numerically less than
   883      *          {@code f2}; and a value greater than {@code 0}
   884      *          if {@code f1} is numerically greater than
   885      *          {@code f2}.
   886      * @since 1.4
   887      */
   888     public static int compare(float f1, float f2) {
   889         if (f1 < f2)
   890             return -1;           // Neither val is NaN, thisVal is smaller
   891         if (f1 > f2)
   892             return 1;            // Neither val is NaN, thisVal is larger
   893 
   894         // Cannot use floatToRawIntBits because of possibility of NaNs.
   895         int thisBits    = Float.floatToIntBits(f1);
   896         int anotherBits = Float.floatToIntBits(f2);
   897 
   898         return (thisBits == anotherBits ?  0 : // Values are equal
   899                 (thisBits < anotherBits ? -1 : // (-0.0, 0.0) or (!NaN, NaN)
   900                  1));                          // (0.0, -0.0) or (NaN, !NaN)
   901     }
   902 
   903     /** use serialVersionUID from JDK 1.0.2 for interoperability */
   904     private static final long serialVersionUID = -2671257302660747028L;
   905 }