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  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

  *

  * This code is free software; you can redistribute it and/or modify it

  * under the terms of the GNU General Public License version 2 only, as

  * published by the Free Software Foundation.  Oracle designates this

  * particular file as subject to the "Classpath" exception as provided

  * by Oracle in the LICENSE file that accompanied this code.

  *

  * This code is distributed in the hope that it will be useful, but WITHOUT

  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

  * version 2 for more details (a copy is included in the LICENSE file that

  * accompanied this code).

  *

  * You should have received a copy of the GNU General Public License version

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  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

  *

  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

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 package java.lang;

 import sun.misc.FloatingDecimal;

 import sun.misc.FpUtils;

 import sun.misc.DoubleConsts;

 /**

  * The {@code Double} class wraps a value of the primitive type

  * {@code double} in an object. An object of type

  * {@code Double} contains a single field whose type is

  * {@code double}.

  *

  * <p>In addition, this class provides several methods for converting a

  * {@code double} to a {@code String} and a

  * {@code String} to a {@code double}, as well as other

  * constants and methods useful when dealing with a

  * {@code double}.

  *

  * @author  Lee Boynton

  * @author  Arthur van Hoff

  * @author  Joseph D. Darcy

  * @since JDK1.0

  */

 public final class Double extends Number implements Comparable<Double> {

     /**

      * A constant holding the positive infinity of type

      * {@code double}. It is equal to the value returned by

      * {@code Double.longBitsToDouble(0x7ff0000000000000L)}.

      */

     public static final double POSITIVE_INFINITY = 1.0 / 0.0;

     /**

      * A constant holding the negative infinity of type

      * {@code double}. It is equal to the value returned by

      * {@code Double.longBitsToDouble(0xfff0000000000000L)}.

      */

     public static final double NEGATIVE_INFINITY = -1.0 / 0.0;

     /**

      * A constant holding a Not-a-Number (NaN) value of type

      * {@code double}. It is equivalent to the value returned by

      * {@code Double.longBitsToDouble(0x7ff8000000000000L)}.

      */

     public static final double NaN = 0.0d / 0.0;

     /**

      * A constant holding the largest positive finite value of type

      * {@code double},

      * (2-2<sup>-52</sup>)&middot;2<sup>1023</sup>.  It is equal to

      * the hexadecimal floating-point literal

      * {@code 0x1.fffffffffffffP+1023} and also equal to

      * {@code Double.longBitsToDouble(0x7fefffffffffffffL)}.

      */

     public static final double MAX_VALUE = 0x1.fffffffffffffP+1023; // 1.7976931348623157e+308

     /**

      * A constant holding the smallest positive normal value of type

      * {@code double}, 2<sup>-1022</sup>.  It is equal to the

      * hexadecimal floating-point literal {@code 0x1.0p-1022} and also

      * equal to {@code Double.longBitsToDouble(0x0010000000000000L)}.

      *

      * @since 1.6

      */

     public static final double MIN_NORMAL = 0x1.0p-1022; // 2.2250738585072014E-308

     /**

      * A constant holding the smallest positive nonzero value of type

      * {@code double}, 2<sup>-1074</sup>. It is equal to the

      * hexadecimal floating-point literal

      * {@code 0x0.0000000000001P-1022} and also equal to

      * {@code Double.longBitsToDouble(0x1L)}.

      */

     public static final double MIN_VALUE = 0x0.0000000000001P-1022; // 4.9e-324

     /**

      * Maximum exponent a finite {@code double} variable may have.

      * It is equal to the value returned by

      * {@code Math.getExponent(Double.MAX_VALUE)}.

      *

      * @since 1.6

      */

     public static final int MAX_EXPONENT = 1023;

     /**

      * Minimum exponent a normalized {@code double} variable may

      * have.  It is equal to the value returned by

      * {@code Math.getExponent(Double.MIN_NORMAL)}.

      *

      * @since 1.6

      */

     public static final int MIN_EXPONENT = -1022;

     /**

      * The number of bits used to represent a {@code double} value.

      *

      * @since 1.5

      */

     public static final int SIZE = 64;

     /**

      * The {@code Class} instance representing the primitive type

      * {@code double}.

      *

      * @since JDK1.1

      */

     public static final Class<Double>   TYPE = (Class<Double>) Class.getPrimitiveClass("double");

     /**

      * Returns a string representation of the {@code double}

      * argument. All characters mentioned below are ASCII characters.

      * <ul>

      * <li>If the argument is NaN, the result is the string

      *     "{@code NaN}".

      * <li>Otherwise, the result is a string that represents the sign and

      * magnitude (absolute value) of the argument. If the sign is negative,

      * the first character of the result is '{@code -}'

      * (<code>'&#92;u002D'</code>); if the sign is positive, no sign character

      * appears in the result. As for the magnitude <i>m</i>:

      * <ul>

      * <li>If <i>m</i> is infinity, it is represented by the characters

      * {@code "Infinity"}; thus, positive infinity produces the result

      * {@code "Infinity"} and negative infinity produces the result

      * {@code "-Infinity"}.

      *

      * <li>If <i>m</i> is zero, it is represented by the characters

      * {@code "0.0"}; thus, negative zero produces the result

      * {@code "-0.0"} and positive zero produces the result

      * {@code "0.0"}.

      *

      * <li>If <i>m</i> is greater than or equal to 10<sup>-3</sup> but less

      * than 10<sup>7</sup>, then it is represented as the integer part of

      * <i>m</i>, in decimal form with no leading zeroes, followed by

      * '{@code .}' (<code>'&#92;u002E'</code>), followed by one or

      * more decimal digits representing the fractional part of <i>m</i>.

      *

      * <li>If <i>m</i> is less than 10<sup>-3</sup> or greater than or

      * equal to 10<sup>7</sup>, then it is represented in so-called

      * "computerized scientific notation." Let <i>n</i> be the unique

      * integer such that 10<sup><i>n</i></sup> &le; <i>m</i> {@literal <}

      * 10<sup><i>n</i>+1</sup>; then let <i>a</i> be the

      * mathematically exact quotient of <i>m</i> and

      * 10<sup><i>n</i></sup> so that 1 &le; <i>a</i> {@literal <} 10. The

      * magnitude is then represented as the integer part of <i>a</i>,

      * as a single decimal digit, followed by '{@code .}'

      * (<code>'&#92;u002E'</code>), followed by decimal digits

      * representing the fractional part of <i>a</i>, followed by the

      * letter '{@code E}' (<code>'&#92;u0045'</code>), followed

      * by a representation of <i>n</i> as a decimal integer, as

      * produced by the method {@link Integer#toString(int)}.

      * </ul>

      * </ul>

      * How many digits must be printed for the fractional part of

      * <i>m</i> or <i>a</i>? There must be at least one digit to represent

      * the fractional part, and beyond that as many, but only as many, more

      * digits as are needed to uniquely distinguish the argument value from

      * adjacent values of type {@code double}. That is, suppose that

      * <i>x</i> is the exact mathematical value represented by the decimal

      * representation produced by this method for a finite nonzero argument

      * <i>d</i>. Then <i>d</i> must be the {@code double} value nearest

      * to <i>x</i>; or if two {@code double} values are equally close

      * to <i>x</i>, then <i>d</i> must be one of them and the least

      * significant bit of the significand of <i>d</i> must be {@code 0}.

      *

      * <p>To create localized string representations of a floating-point

      * value, use subclasses of {@link java.text.NumberFormat}.

      *

      * @param   d   the {@code double} to be converted.

      * @return a string representation of the argument.

      */

     public static String toString(double d) {

         return new FloatingDecimal(d).toJavaFormatString();

     }

     /**

      * Returns a hexadecimal string representation of the

      * {@code double} argument. All characters mentioned below

      * are ASCII characters.

      *

      * <ul>

      * <li>If the argument is NaN, the result is the string

      *     "{@code NaN}".

      * <li>Otherwise, the result is a string that represents the sign

      * and magnitude of the argument. If the sign is negative, the

      * first character of the result is '{@code -}'

      * (<code>'&#92;u002D'</code>); if the sign is positive, no sign

      * character appears in the result. As for the magnitude <i>m</i>:

      *

      * <ul>

      * <li>If <i>m</i> is infinity, it is represented by the string

      * {@code "Infinity"}; thus, positive infinity produces the

      * result {@code "Infinity"} and negative infinity produces

      * the result {@code "-Infinity"}.

      *

      * <li>If <i>m</i> is zero, it is represented by the string

      * {@code "0x0.0p0"}; thus, negative zero produces the result

      * {@code "-0x0.0p0"} and positive zero produces the result

      * {@code "0x0.0p0"}.

      *

      * <li>If <i>m</i> is a {@code double} value with a

      * normalized representation, substrings are used to represent the

      * significand and exponent fields.  The significand is

      * represented by the characters {@code "0x1."}

      * followed by a lowercase hexadecimal representation of the rest

      * of the significand as a fraction.  Trailing zeros in the

      * hexadecimal representation are removed unless all the digits

      * are zero, in which case a single zero is used. Next, the

      * exponent is represented by {@code "p"} followed

      * by a decimal string of the unbiased exponent as if produced by

      * a call to {@link Integer#toString(int) Integer.toString} on the

      * exponent value.

      *

      * <li>If <i>m</i> is a {@code double} value with a subnormal

      * representation, the significand is represented by the

      * characters {@code "0x0."} followed by a

      * hexadecimal representation of the rest of the significand as a

      * fraction.  Trailing zeros in the hexadecimal representation are

      * removed. Next, the exponent is represented by

      * {@code "p-1022"}.  Note that there must be at

      * least one nonzero digit in a subnormal significand.

      *

      * </ul>

      *

      * </ul>

      *

      * <table border>

      * <caption><h3>Examples</h3></caption>

      * <tr><th>Floating-point Value</th><th>Hexadecimal String</th>

      * <tr><td>{@code 1.0}</td> <td>{@code 0x1.0p0}</td>

      * <tr><td>{@code -1.0}</td>        <td>{@code -0x1.0p0}</td>

      * <tr><td>{@code 2.0}</td> <td>{@code 0x1.0p1}</td>

      * <tr><td>{@code 3.0}</td> <td>{@code 0x1.8p1}</td>

      * <tr><td>{@code 0.5}</td> <td>{@code 0x1.0p-1}</td>

      * <tr><td>{@code 0.25}</td>        <td>{@code 0x1.0p-2}</td>

      * <tr><td>{@code Double.MAX_VALUE}</td>

      *     <td>{@code 0x1.fffffffffffffp1023}</td>

      * <tr><td>{@code Minimum Normal Value}</td>

      *     <td>{@code 0x1.0p-1022}</td>

      * <tr><td>{@code Maximum Subnormal Value}</td>

      *     <td>{@code 0x0.fffffffffffffp-1022}</td>

      * <tr><td>{@code Double.MIN_VALUE}</td>

      *     <td>{@code 0x0.0000000000001p-1022}</td>

      * </table>

      * @param   d   the {@code double} to be converted.

      * @return a hex string representation of the argument.

      * @since 1.5

      * @author Joseph D. Darcy

      */

     public static String toHexString(double d) {

         /*

          * Modeled after the "a" conversion specifier in C99, section

          * 7.19.6.1; however, the output of this method is more

          * tightly specified.

          */

         if (!FpUtils.isFinite(d) )

             // For infinity and NaN, use the decimal output.

             return Double.toString(d);

         else {

             // Initialized to maximum size of output.

             StringBuffer answer = new StringBuffer(24);

             if (FpUtils.rawCopySign(1.0, d) == -1.0) // value is negative,

                 answer.append("-");                  // so append sign info

             answer.append("0x");

             d = Math.abs(d);

             if(d == 0.0) {

                 answer.append("0.0p0");

             }

             else {

                 boolean subnormal = (d < DoubleConsts.MIN_NORMAL);

                 // Isolate significand bits and OR in a high-order bit

                 // so that the string representation has a known

                 // length.

                 long signifBits = (Double.doubleToLongBits(d)

                                    & DoubleConsts.SIGNIF_BIT_MASK) |

                     0x1000000000000000L;

                 // Subnormal values have a 0 implicit bit; normal

                 // values have a 1 implicit bit.

                 answer.append(subnormal ? "0." : "1.");

                 // Isolate the low-order 13 digits of the hex

                 // representation.  If all the digits are zero,

                 // replace with a single 0; otherwise, remove all

                 // trailing zeros.

                 String signif = Long.toHexString(signifBits).substring(3,16);

                 answer.append(signif.equals("0000000000000") ? // 13 zeros

                               "0":

                               signif.replaceFirst("0{1,12}$", ""));

                 // If the value is subnormal, use the E_min exponent

                 // value for double; otherwise, extract and report d's

                 // exponent (the representation of a subnormal uses

                 // E_min -1).

                 answer.append("p" + (subnormal ?

                                DoubleConsts.MIN_EXPONENT:

                                FpUtils.getExponent(d) ));

             }

             return answer.toString();

         }

     }

     /**

      * Returns a {@code Double} object holding the

      * {@code double} value represented by the argument string

      * {@code s}.

      *

      * <p>If {@code s} is {@code null}, then a

      * {@code NullPointerException} is thrown.

      *

      * <p>Leading and trailing whitespace characters in {@code s}

      * are ignored.  Whitespace is removed as if by the {@link

      * String#trim} method; that is, both ASCII space and control

      * characters are removed. The rest of {@code s} should

      * constitute a <i>FloatValue</i> as described by the lexical

      * syntax rules:

      *

      * <blockquote>

      * <dl>

      * <dt><i>FloatValue:</i>

      * <dd><i>Sign<sub>opt</sub></i> {@code NaN}

      * <dd><i>Sign<sub>opt</sub></i> {@code Infinity}

      * <dd><i>Sign<sub>opt</sub> FloatingPointLiteral</i>

      * <dd><i>Sign<sub>opt</sub> HexFloatingPointLiteral</i>

      * <dd><i>SignedInteger</i>

      * </dl>

      *

      * <p>

      *

      * <dl>

      * <dt><i>HexFloatingPointLiteral</i>:

      * <dd> <i>HexSignificand BinaryExponent FloatTypeSuffix<sub>opt</sub></i>

      * </dl>

      *

      * <p>

      *

      * <dl>

      * <dt><i>HexSignificand:</i>

      * <dd><i>HexNumeral</i>

      * <dd><i>HexNumeral</i> {@code .}

      * <dd>{@code 0x} <i>HexDigits<sub>opt</sub>

      *     </i>{@code .}<i> HexDigits</i>

      * <dd>{@code 0X}<i> HexDigits<sub>opt</sub>

      *     </i>{@code .} <i>HexDigits</i>

      * </dl>

      *

      * <p>

      *

      * <dl>

      * <dt><i>BinaryExponent:</i>

      * <dd><i>BinaryExponentIndicator SignedInteger</i>

      * </dl>

      *

      * <p>

      *

      * <dl>

      * <dt><i>BinaryExponentIndicator:</i>

      * <dd>{@code p}

      * <dd>{@code P}

      * </dl>

      *

      * </blockquote>

      *

      * where <i>Sign</i>, <i>FloatingPointLiteral</i>,

      * <i>HexNumeral</i>, <i>HexDigits</i>, <i>SignedInteger</i> and

      * <i>FloatTypeSuffix</i> are as defined in the lexical structure

      * sections of

      * <cite>The Java&trade; Language Specification</cite>,

      * except that underscores are not accepted between digits.

      * If {@code s} does not have the form of

      * a <i>FloatValue</i>, then a {@code NumberFormatException}

      * is thrown. Otherwise, {@code s} is regarded as

      * representing an exact decimal value in the usual

      * "computerized scientific notation" or as an exact

      * hexadecimal value; this exact numerical value is then

      * conceptually converted to an "infinitely precise"

      * binary value that is then rounded to type {@code double}

      * by the usual round-to-nearest rule of IEEE 754 floating-point

      * arithmetic, which includes preserving the sign of a zero

      * value.

      *

      * Note that the round-to-nearest rule also implies overflow and

      * underflow behaviour; if the exact value of {@code s} is large

      * enough in magnitude (greater than or equal to ({@link

      * #MAX_VALUE} + {@link Math#ulp(double) ulp(MAX_VALUE)}/2),

      * rounding to {@code double} will result in an infinity and if the

      * exact value of {@code s} is small enough in magnitude (less

      * than or equal to {@link #MIN_VALUE}/2), rounding to float will

      * result in a zero.

      *

      * Finally, after rounding a {@code Double} object representing

      * this {@code double} value is returned.

      *

      * <p> To interpret localized string representations of a

      * floating-point value, use subclasses of {@link

      * java.text.NumberFormat}.

      *

      * <p>Note that trailing format specifiers, specifiers that

      * determine the type of a floating-point literal

      * ({@code 1.0f} is a {@code float} value;

      * {@code 1.0d} is a {@code double} value), do

      * <em>not</em> influence the results of this method.  In other

      * words, the numerical value of the input string is converted

      * directly to the target floating-point type.  The two-step

      * sequence of conversions, string to {@code float} followed

      * by {@code float} to {@code double}, is <em>not</em>

      * equivalent to converting a string directly to

      * {@code double}. For example, the {@code float}

      * literal {@code 0.1f} is equal to the {@code double}

      * value {@code 0.10000000149011612}; the {@code float}

      * literal {@code 0.1f} represents a different numerical

      * value than the {@code double} literal

      * {@code 0.1}. (The numerical value 0.1 cannot be exactly

      * represented in a binary floating-point number.)

      *

      * <p>To avoid calling this method on an invalid string and having

      * a {@code NumberFormatException} be thrown, the regular

      * expression below can be used to screen the input string:

      *

      * <code>

      * <pre>

      *  final String Digits     = "(\\p{Digit}+)";

      *  final String HexDigits  = "(\\p{XDigit}+)";

      *  // an exponent is 'e' or 'E' followed by an optionally

      *  // signed decimal integer.

      *  final String Exp        = "[eE][+-]?"+Digits;

      *  final String fpRegex    =

      *      ("[\\x00-\\x20]*"+  // Optional leading "whitespace"

      *       "[+-]?(" + // Optional sign character

      *       "NaN|" +           // "NaN" string

      *       "Infinity|" +      // "Infinity" string

      *

      *       // A decimal floating-point string representing a finite positive

      *       // number without a leading sign has at most five basic pieces:

      *       // Digits . Digits ExponentPart FloatTypeSuffix

      *       //

      *       // Since this method allows integer-only strings as input

      *       // in addition to strings of floating-point literals, the

      *       // two sub-patterns below are simplifications of the grammar

      *       // productions from section 3.10.2 of

      *       // <cite>The Java&trade; Language Specification</cite>.

      *

      *       // Digits ._opt Digits_opt ExponentPart_opt FloatTypeSuffix_opt

      *       "((("+Digits+"(\\.)?("+Digits+"?)("+Exp+")?)|"+

      *

      *       // . Digits ExponentPart_opt FloatTypeSuffix_opt

      *       "(\\.("+Digits+")("+Exp+")?)|"+

      *

      *       // Hexadecimal strings

      *       "((" +

      *        // 0[xX] HexDigits ._opt BinaryExponent FloatTypeSuffix_opt

      *        "(0[xX]" + HexDigits + "(\\.)?)|" +

      *

      *        // 0[xX] HexDigits_opt . HexDigits BinaryExponent FloatTypeSuffix_opt

      *        "(0[xX]" + HexDigits + "?(\\.)" + HexDigits + ")" +

      *

      *        ")[pP][+-]?" + Digits + "))" +

      *       "[fFdD]?))" +

      *       "[\\x00-\\x20]*");// Optional trailing "whitespace"

      *

      *  if (Pattern.matches(fpRegex, myString))

      *      Double.valueOf(myString); // Will not throw NumberFormatException

      *  else {

      *      // Perform suitable alternative action

      *  }

      * </pre>

      * </code>

      *

      * @param      s   the string to be parsed.

      * @return     a {@code Double} object holding the value

      *             represented by the {@code String} argument.

      * @throws     NumberFormatException  if the string does not contain a

      *             parsable number.

      */

     public static Double valueOf(String s) throws NumberFormatException {

         return new Double(FloatingDecimal.readJavaFormatString(s).doubleValue());

     }

     /**

      * Returns a {@code Double} instance representing the specified

      * {@code double} value.

      * If a new {@code Double} instance is not required, this method

      * should generally be used in preference to the constructor

      * {@link #Double(double)}, as this method is likely to yield

      * significantly better space and time performance by caching

      * frequently requested values.

      *

      * @param  d a double value.

      * @return a {@code Double} instance representing {@code d}.

      * @since  1.5

      */

     public static Double valueOf(double d) {

         return new Double(d);

     }

     /**

      * Returns a new {@code double} initialized to the value

      * represented by the specified {@code String}, as performed

      * by the {@code valueOf} method of class

      * {@code Double}.

      *

      * @param  s   the string to be parsed.

      * @return the {@code double} value represented by the string

      *         argument.

      * @throws NullPointerException  if the string is null

      * @throws NumberFormatException if the string does not contain

      *         a parsable {@code double}.

      * @see    java.lang.Double#valueOf(String)

      * @since 1.2

      */

     public static double parseDouble(String s) throws NumberFormatException {

         return FloatingDecimal.readJavaFormatString(s).doubleValue();

     }

     /**

      * Returns {@code true} if the specified number is a

      * Not-a-Number (NaN) value, {@code false} otherwise.

      *

      * @param   v   the value to be tested.

      * @return  {@code true} if the value of the argument is NaN;

      *          {@code false} otherwise.

      */

     static public boolean isNaN(double v) {

         return (v != v);

     }

     /**

      * Returns {@code true} if the specified number is infinitely

      * large in magnitude, {@code false} otherwise.

      *

      * @param   v   the value to be tested.

      * @return  {@code true} if the value of the argument is positive

      *          infinity or negative infinity; {@code false} otherwise.

      */

     static public boolean isInfinite(double v) {

         return (v == POSITIVE_INFINITY) || (v == NEGATIVE_INFINITY);

     }

     /**

      * The value of the Double.

      *

      * @serial

      */

     private final double value;

     /**

      * Constructs a newly allocated {@code Double} object that

      * represents the primitive {@code double} argument.

      *

      * @param   value   the value to be represented by the {@code Double}.

      */

     public Double(double value) {

         this.value = value;

     }

     /**

      * Constructs a newly allocated {@code Double} object that

      * represents the floating-point value of type {@code double}

      * represented by the string. The string is converted to a

      * {@code double} value as if by the {@code valueOf} method.

      *

      * @param  s  a string to be converted to a {@code Double}.

      * @throws    NumberFormatException  if the string does not contain a

      *            parsable number.

      * @see       java.lang.Double#valueOf(java.lang.String)

      */

     public Double(String s) throws NumberFormatException {

         // REMIND: this is inefficient

         this(valueOf(s).doubleValue());

     }

     /**

      * Returns {@code true} if this {@code Double} value is

      * a Not-a-Number (NaN), {@code false} otherwise.

      *

      * @return  {@code true} if the value represented by this object is

      *          NaN; {@code false} otherwise.

      */

     public boolean isNaN() {

         return isNaN(value);

     }

     /**

      * Returns {@code true} if this {@code Double} value is

      * infinitely large in magnitude, {@code false} otherwise.

      *

      * @return  {@code true} if the value represented by this object is

      *          positive infinity or negative infinity;

      *          {@code false} otherwise.

      */

     public boolean isInfinite() {

         return isInfinite(value);

     }

     /**

      * Returns a string representation of this {@code Double} object.

      * The primitive {@code double} value represented by this

      * object is converted to a string exactly as if by the method

      * {@code toString} of one argument.

      *

      * @return  a {@code String} representation of this object.

      * @see java.lang.Double#toString(double)

      */

     public String toString() {

         return toString(value);

     }

     /**

      * Returns the value of this {@code Double} as a {@code byte} (by

      * casting to a {@code byte}).

      *

      * @return  the {@code double} value represented by this object

      *          converted to type {@code byte}

      * @since JDK1.1

      */

     public byte byteValue() {

         return (byte)value;

     }

     /**

      * Returns the value of this {@code Double} as a

      * {@code short} (by casting to a {@code short}).

      *

      * @return  the {@code double} value represented by this object

      *          converted to type {@code short}

      * @since JDK1.1

      */

     public short shortValue() {

         return (short)value;

     }

     /**

      * Returns the value of this {@code Double} as an

      * {@code int} (by casting to type {@code int}).

      *

      * @return  the {@code double} value represented by this object

      *          converted to type {@code int}

      */

     public int intValue() {

         return (int)value;

     }

     /**

      * Returns the value of this {@code Double} as a

      * {@code long} (by casting to type {@code long}).

      *

      * @return  the {@code double} value represented by this object

      *          converted to type {@code long}

      */

     public long longValue() {

         return (long)value;

     }

     /**

      * Returns the {@code float} value of this

      * {@code Double} object.

      *

      * @return  the {@code double} value represented by this object

      *          converted to type {@code float}

      * @since JDK1.0

      */

     public float floatValue() {

         return (float)value;

     }

     /**

      * Returns the {@code double} value of this

      * {@code Double} object.

      *

      * @return the {@code double} value represented by this object

      */

     public double doubleValue() {

         return (double)value;

     }

     /**

      * Returns a hash code for this {@code Double} object. The

      * result is the exclusive OR of the two halves of the

      * {@code long} integer bit representation, exactly as

      * produced by the method {@link #doubleToLongBits(double)}, of

      * the primitive {@code double} value represented by this

      * {@code Double} object. That is, the hash code is the value

      * of the expression:

      *

      * <blockquote>

      *  {@code (int)(v^(v>>>32))}

      * </blockquote>

      *

      * where {@code v} is defined by:

      *

      * <blockquote>

      *  {@code long v = Double.doubleToLongBits(this.doubleValue());}

      * </blockquote>

      *

      * @return  a {@code hash code} value for this object.

      */

     public int hashCode() {

         long bits = doubleToLongBits(value);

         return (int)(bits ^ (bits >>> 32));

     }

     /**

      * Compares this object against the specified object.  The result

      * is {@code true} if and only if the argument is not

      * {@code null} and is a {@code Double} object that

      * represents a {@code double} that has the same value as the

      * {@code double} represented by this object. For this

      * purpose, two {@code double} values are considered to be

      * the same if and only if the method {@link

      * #doubleToLongBits(double)} returns the identical

      * {@code long} value when applied to each.

      *

      * <p>Note that in most cases, for two instances of class

      * {@code Double}, {@code d1} and {@code d2}, the

      * value of {@code d1.equals(d2)} is {@code true} if and

      * only if

      *

      * <blockquote>

      *  {@code d1.doubleValue() == d2.doubleValue()}

      * </blockquote>

      *

      * <p>also has the value {@code true}. However, there are two

      * exceptions:

      * <ul>

      * <li>If {@code d1} and {@code d2} both represent

      *     {@code Double.NaN}, then the {@code equals} method

      *     returns {@code true}, even though

      *     {@code Double.NaN==Double.NaN} has the value

      *     {@code false}.

      * <li>If {@code d1} represents {@code +0.0} while

      *     {@code d2} represents {@code -0.0}, or vice versa,

      *     the {@code equal} test has the value {@code false},

      *     even though {@code +0.0==-0.0} has the value {@code true}.

      * </ul>

      * This definition allows hash tables to operate properly.

      * @param   obj   the object to compare with.

      * @return  {@code true} if the objects are the same;

      *          {@code false} otherwise.

      * @see java.lang.Double#doubleToLongBits(double)

      */

     public boolean equals(Object obj) {

         return (obj instanceof Double)

                && (doubleToLongBits(((Double)obj).value) ==

                       doubleToLongBits(value));

     }

     /**

      * Returns a representation of the specified floating-point value

      * according to the IEEE 754 floating-point "double

      * format" bit layout.

      *

      * <p>Bit 63 (the bit that is selected by the mask

      * {@code 0x8000000000000000L}) represents the sign of the

      * floating-point number. Bits

      * 62-52 (the bits that are selected by the mask

      * {@code 0x7ff0000000000000L}) represent the exponent. Bits 51-0

      * (the bits that are selected by the mask

      * {@code 0x000fffffffffffffL}) represent the significand

      * (sometimes called the mantissa) of the floating-point number.

      *

      * <p>If the argument is positive infinity, the result is

      * {@code 0x7ff0000000000000L}.

      *

      * <p>If the argument is negative infinity, the result is

      * {@code 0xfff0000000000000L}.

      *

      * <p>If the argument is NaN, the result is

      * {@code 0x7ff8000000000000L}.

      *

      * <p>In all cases, the result is a {@code long} integer that, when

      * given to the {@link #longBitsToDouble(long)} method, will produce a

      * floating-point value the same as the argument to

      * {@code doubleToLongBits} (except all NaN values are

      * collapsed to a single "canonical" NaN value).

      *

      * @param   value   a {@code double} precision floating-point number.

      * @return the bits that represent the floating-point number.

      */

     public static long doubleToLongBits(double value) {

         long result = doubleToRawLongBits(value);

         // Check for NaN based on values of bit fields, maximum

         // exponent and nonzero significand.

         if ( ((result & DoubleConsts.EXP_BIT_MASK) ==

               DoubleConsts.EXP_BIT_MASK) &&

              (result & DoubleConsts.SIGNIF_BIT_MASK) != 0L)

             result = 0x7ff8000000000000L;

         return result;

     }

     /**

      * Returns a representation of the specified floating-point value

      * according to the IEEE 754 floating-point "double

      * format" bit layout, preserving Not-a-Number (NaN) values.

      *

      * <p>Bit 63 (the bit that is selected by the mask

      * {@code 0x8000000000000000L}) represents the sign of the

      * floating-point number. Bits

      * 62-52 (the bits that are selected by the mask

      * {@code 0x7ff0000000000000L}) represent the exponent. Bits 51-0

      * (the bits that are selected by the mask

      * {@code 0x000fffffffffffffL}) represent the significand

      * (sometimes called the mantissa) of the floating-point number.

      *

      * <p>If the argument is positive infinity, the result is

      * {@code 0x7ff0000000000000L}.

      *

      * <p>If the argument is negative infinity, the result is

      * {@code 0xfff0000000000000L}.

      *

      * <p>If the argument is NaN, the result is the {@code long}

      * integer representing the actual NaN value.  Unlike the

      * {@code doubleToLongBits} method,

      * {@code doubleToRawLongBits} does not collapse all the bit

      * patterns encoding a NaN to a single "canonical" NaN

      * value.

      *

      * <p>In all cases, the result is a {@code long} integer that,

      * when given to the {@link #longBitsToDouble(long)} method, will

      * produce a floating-point value the same as the argument to

      * {@code doubleToRawLongBits}.

      *

      * @param   value   a {@code double} precision floating-point number.

      * @return the bits that represent the floating-point number.

      * @since 1.3

      */

     public static native long doubleToRawLongBits(double value);

     /**

      * Returns the {@code double} value corresponding to a given

      * bit representation.

      * The argument is considered to be a representation of a

      * floating-point value according to the IEEE 754 floating-point

      * "double format" bit layout.

      *

      * <p>If the argument is {@code 0x7ff0000000000000L}, the result

      * is positive infinity.

      *

      * <p>If the argument is {@code 0xfff0000000000000L}, the result

      * is negative infinity.

      *

      * <p>If the argument is any value in the range

      * {@code 0x7ff0000000000001L} through

      * {@code 0x7fffffffffffffffL} or in the range

      * {@code 0xfff0000000000001L} through

      * {@code 0xffffffffffffffffL}, the result is a NaN.  No IEEE

      * 754 floating-point operation provided by Java can distinguish

      * between two NaN values of the same type with different bit

      * patterns.  Distinct values of NaN are only distinguishable by

      * use of the {@code Double.doubleToRawLongBits} method.

      *

      * <p>In all other cases, let <i>s</i>, <i>e</i>, and <i>m</i> be three

      * values that can be computed from the argument:

      *

      * <blockquote><pre>

      * int s = ((bits >> 63) == 0) ? 1 : -1;

      * int e = (int)((bits >> 52) & 0x7ffL);

      * long m = (e == 0) ?

      *                 (bits & 0xfffffffffffffL) << 1 :

      *                 (bits & 0xfffffffffffffL) | 0x10000000000000L;

      * </pre></blockquote>

      *

      * Then the floating-point result equals the value of the mathematical

      * expression <i>s</i>&middot;<i>m</i>&middot;2<sup><i>e</i>-1075</sup>.

      *

      * <p>Note that this method may not be able to return a

      * {@code double} NaN with exactly same bit pattern as the

      * {@code long} argument.  IEEE 754 distinguishes between two

      * kinds of NaNs, quiet NaNs and <i>signaling NaNs</i>.  The

      * differences between the two kinds of NaN are generally not

      * visible in Java.  Arithmetic operations on signaling NaNs turn

      * them into quiet NaNs with a different, but often similar, bit

      * pattern.  However, on some processors merely copying a

      * signaling NaN also performs that conversion.  In particular,

      * copying a signaling NaN to return it to the calling method

      * may perform this conversion.  So {@code longBitsToDouble}

      * may not be able to return a {@code double} with a

      * signaling NaN bit pattern.  Consequently, for some

      * {@code long} values,

      * {@code doubleToRawLongBits(longBitsToDouble(start))} may

      * <i>not</i> equal {@code start}.  Moreover, which

      * particular bit patterns represent signaling NaNs is platform

      * dependent; although all NaN bit patterns, quiet or signaling,

      * must be in the NaN range identified above.

      *

      * @param   bits   any {@code long} integer.

      * @return  the {@code double} floating-point value with the same

      *          bit pattern.

      */

     public static native double longBitsToDouble(long bits);

     /**

      * Compares two {@code Double} objects numerically.  There

      * are two ways in which comparisons performed by this method

      * differ from those performed by the Java language numerical

      * comparison operators ({@code <, <=, ==, >=, >})

      * when applied to primitive {@code double} values:

      * <ul><li>

      *          {@code Double.NaN} is considered by this method

      *          to be equal to itself and greater than all other

      *          {@code double} values (including

      *          {@code Double.POSITIVE_INFINITY}).

      * <li>

      *          {@code 0.0d} is considered by this method to be greater

      *          than {@code -0.0d}.

      * </ul>

      * This ensures that the <i>natural ordering</i> of

      * {@code Double} objects imposed by this method is <i>consistent

      * with equals</i>.

      *

      * @param   anotherDouble   the {@code Double} to be compared.

      * @return  the value {@code 0} if {@code anotherDouble} is

      *          numerically equal to this {@code Double}; a value

      *          less than {@code 0} if this {@code Double}

      *          is numerically less than {@code anotherDouble};

      *          and a value greater than {@code 0} if this

      *          {@code Double} is numerically greater than

      *          {@code anotherDouble}.

      *

      * @since   1.2

      */

     public int compareTo(Double anotherDouble) {

         return Double.compare(value, anotherDouble.value);

     }

     /**

      * Compares the two specified {@code double} values. The sign

      * of the integer value returned is the same as that of the

      * integer that would be returned by the call:

      * <pre>

      *    new Double(d1).compareTo(new Double(d2))

      * </pre>

      *

      * @param   d1        the first {@code double} to compare

      * @param   d2        the second {@code double} to compare

      * @return  the value {@code 0} if {@code d1} is

      *          numerically equal to {@code d2}; a value less than

      *          {@code 0} if {@code d1} is numerically less than

      *          {@code d2}; and a value greater than {@code 0}

      *          if {@code d1} is numerically greater than

      *          {@code d2}.

      * @since 1.4

      */

     public static int compare(double d1, double d2) {

         if (d1 < d2)

             return -1;           // Neither val is NaN, thisVal is smaller

         if (d1 > d2)

             return 1;            // Neither val is NaN, thisVal is larger

         // Cannot use doubleToRawLongBits because of possibility of NaNs.

         long thisBits    = Double.doubleToLongBits(d1);

         long anotherBits = Double.doubleToLongBits(d2);

         return (thisBits == anotherBits ?  0 : // Values are equal

                 (thisBits < anotherBits ? -1 : // (-0.0, 0.0) or (!NaN, NaN)

                  1));                          // (0.0, -0.0) or (NaN, !NaN)

     }

     /** use serialVersionUID from JDK 1.0.2 for interoperability */

     private static final long serialVersionUID = -9172774392245257468L;

 }