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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.FloatConsts;

 import sun.misc.DoubleConsts;

 /**

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

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

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

  * {@code float}.

  *

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

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

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

  * constants and methods useful when dealing with a

  * {@code float}.

  *

  * @author  Lee Boynton

  * @author  Arthur van Hoff

  * @author  Joseph D. Darcy

  * @since JDK1.0

  */

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

     /**

      * A constant holding the positive infinity of type

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

      * {@code Float.intBitsToFloat(0x7f800000)}.

      */

     public static final float POSITIVE_INFINITY = 1.0f / 0.0f;

     /**

      * A constant holding the negative infinity of type

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

      * {@code Float.intBitsToFloat(0xff800000)}.

      */

     public static final float NEGATIVE_INFINITY = -1.0f / 0.0f;

     /**

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

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

      * {@code Float.intBitsToFloat(0x7fc00000)}.

      */

     public static final float NaN = 0.0f / 0.0f;

     /**

      * A constant holding the largest positive finite value of type

      * {@code float}, (2-2<sup>-23</sup>)&middot;2<sup>127</sup>.

      * It is equal to the hexadecimal floating-point literal

      * {@code 0x1.fffffeP+127f} and also equal to

      * {@code Float.intBitsToFloat(0x7f7fffff)}.

      */

     public static final float MAX_VALUE = 0x1.fffffeP+127f; // 3.4028235e+38f

     /**

      * A constant holding the smallest positive normal value of type

      * {@code float}, 2<sup>-126</sup>.  It is equal to the

      * hexadecimal floating-point literal {@code 0x1.0p-126f} and also

      * equal to {@code Float.intBitsToFloat(0x00800000)}.

      *

      * @since 1.6

      */

     public static final float MIN_NORMAL = 0x1.0p-126f; // 1.17549435E-38f

     /**

      * A constant holding the smallest positive nonzero value of type

      * {@code float}, 2<sup>-149</sup>. It is equal to the

      * hexadecimal floating-point literal {@code 0x0.000002P-126f}

      * and also equal to {@code Float.intBitsToFloat(0x1)}.

      */

     public static final float MIN_VALUE = 0x0.000002P-126f; // 1.4e-45f

     /**

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

      * is equal to the value returned by {@code

      * Math.getExponent(Float.MAX_VALUE)}.

      *

      * @since 1.6

      */

     public static final int MAX_EXPONENT = 127;

     /**

      * Minimum exponent a normalized {@code float} variable may have.

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

      * Math.getExponent(Float.MIN_NORMAL)}.

      *

      * @since 1.6

      */

     public static final int MIN_EXPONENT = -126;

     /**

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

      *

      * @since 1.5

      */

     public static final int SIZE = 32;

     /**

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

      * {@code float}.

      *

      * @since JDK1.1

      */

     public static final Class<Float> TYPE = Class.getPrimitiveClass("float");

     /**

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

      * 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 java.lang.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 float}. 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>f</i>. Then <i>f</i> must be the {@code float}

      * value nearest to <i>x</i>; or, if two {@code float} values are

      * equally close to <i>x</i>, then <i>f</i> must be one of

      * them and the least significant bit of the significand of

      * <i>f</i> must be {@code 0}.

      *

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

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

      *

      * @param   f   the float to be converted.

      * @return a string representation of the argument.

      */

     public static String toString(float f) {

         return new FloatingDecimal(f).toJavaFormatString();

     }

     /**

      * Returns a hexadecimal string representation of the

      * {@code float} 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 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 float} 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 float} 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-126"}.  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 Float.MAX_VALUE}</td>

      *     <td>{@code 0x1.fffffep127}</td>

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

      *     <td>{@code 0x1.0p-126}</td>

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

      *     <td>{@code 0x0.fffffep-126}</td>

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

      *     <td>{@code 0x0.000002p-126}</td>

      * </table>

      * @param   f   the {@code float} to be converted.

      * @return a hex string representation of the argument.

      * @since 1.5

      * @author Joseph D. Darcy

      */

     public static String toHexString(float f) {

         if (Math.abs(f) < FloatConsts.MIN_NORMAL

             &&  f != 0.0f ) {// float subnormal

             // Adjust exponent to create subnormal double, then

             // replace subnormal double exponent with subnormal float

             // exponent

             String s = Double.toHexString(FpUtils.scalb((double)f,

                                                         /* -1022+126 */

                                                         DoubleConsts.MIN_EXPONENT-

                                                         FloatConsts.MIN_EXPONENT));

             return s.replaceFirst("p-1022$", "p-126");

         }

         else // double string will be the same as float string

             return Double.toHexString(f);

     }

     /**

      * Returns a {@code Float} object holding the

      * {@code float} 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 float}

      * 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(float) ulp(MAX_VALUE)}/2),

      * rounding to {@code float} 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 Float} object representing

      * this {@code float} 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.  In general, the

      * two-step sequence of conversions, string to {@code double}

      * followed by {@code double} to {@code float}, is

      * <em>not</em> equivalent to converting a string directly to

      * {@code float}.  For example, if first converted to an

      * intermediate {@code double} and then to

      * {@code float}, the string<br>

      * {@code "1.00000017881393421514957253748434595763683319091796875001d"}<br>

      * results in the {@code float} value

      * {@code 1.0000002f}; if the string is converted directly to

      * {@code float}, <code>1.000000<b>1</b>f</code> results.

      *

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

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

      * for {@link Double#valueOf Double.valueOf} lists a regular

      * expression which can be used to screen the input.

      *

      * @param   s   the string to be parsed.

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

      *          represented by the {@code String} argument.

      * @throws  NumberFormatException  if the string does not contain a

      *          parsable number.

      */

     public static Float valueOf(String s) throws NumberFormatException {

         return new Float(FloatingDecimal.readJavaFormatString(s).floatValue());

     }

     /**

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

      * {@code float} value.

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

      * should generally be used in preference to the constructor

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

      * significantly better space and time performance by caching

      * frequently requested values.

      *

      * @param  f a float value.

      * @return a {@code Float} instance representing {@code f}.

      * @since  1.5

      */

     public static Float valueOf(float f) {

         return new Float(f);

     }

     /**

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

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

      * by the {@code valueOf} method of class {@code Float}.

      *

      * @param  s the string to be parsed.

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

      *         argument.

      * @throws NullPointerException  if the string is null

      * @throws NumberFormatException if the string does not contain a

      *               parsable {@code float}.

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

      * @since 1.2

      */

     public static float parseFloat(String s) throws NumberFormatException {

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

     }

     /**

      * 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 argument is NaN;

      *          {@code false} otherwise.

      */

     static public boolean isNaN(float 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 argument is positive infinity or

      *          negative infinity; {@code false} otherwise.

      */

     static public boolean isInfinite(float v) {

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

     }

     /**

      * The value of the Float.

      *

      * @serial

      */

     private final float value;

     /**

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

      * represents the primitive {@code float} argument.

      *

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

      */

     public Float(float value) {

         this.value = value;

     }

     /**

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

      * represents the argument converted to type {@code float}.

      *

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

      */

     public Float(double value) {

         this.value = (float)value;

     }

     /**

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

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

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

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

      *

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

      * @throws  NumberFormatException  if the string does not contain a

      *               parsable number.

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

      */

     public Float(String s) throws NumberFormatException {

         // REMIND: this is inefficient

         this(valueOf(s).floatValue());

     }

     /**

      * Returns {@code true} if this {@code Float} 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 Float} 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 Float} object.

      * The primitive {@code float} value represented by this object

      * is converted to a {@code String} exactly as if by the method

      * {@code toString} of one argument.

      *

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

      * @see java.lang.Float#toString(float)

      */

     public String toString() {

         return Float.toString(value);

     }

     /**

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

      * casting to a {@code byte}).

      *

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

      *          converted to type {@code byte}

      */

     public byte byteValue() {

         return (byte)value;

     }

     /**

      * Returns the value of this {@code Float} as a {@code short} (by

      * casting to a {@code short}).

      *

      * @return  the {@code float} 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 Float} as an {@code int} (by

      * casting to type {@code int}).

      *

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

      *          converted to type {@code int}

      */

     public int intValue() {

         return (int)value;

     }

     /**

      * Returns value of this {@code Float} as a {@code long} (by

      * casting to type {@code long}).

      *

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

      *          converted to type {@code long}

      */

     public long longValue() {

         return (long)value;

     }

     /**

      * Returns the {@code float} value of this {@code Float} object.

      *

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

      */

     public float floatValue() {

         return value;

     }

     /**

      * Returns the {@code double} value of this {@code Float} object.

      *

      * @return the {@code float} value represented by this

      *         object is converted to type {@code double} and the

      *         result of the conversion is returned.

      */

     public double doubleValue() {

         return (double)value;

     }

     /**

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

      * result is the integer bit representation, exactly as produced

      * by the method {@link #floatToIntBits(float)}, of the primitive

      * {@code float} value represented by this {@code Float}

      * object.

      *

      * @return a hash code value for this object.

      */

     public int hashCode() {

         return floatToIntBits(value);

     }

     /**

      * 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 Float} object that

      * represents a {@code float} with the same value as the

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

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

      * same if and only if the method {@link #floatToIntBits(float)}

      * returns the identical {@code int} value when applied to

      * each.

      *

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

      * {@code Float}, {@code f1} and {@code f2}, the value

      * of {@code f1.equals(f2)} is {@code true} if and only if

      *

      * <blockquote><pre>

      *   f1.floatValue() == f2.floatValue()

      * </pre></blockquote>

      *

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

      * <ul>

      * <li>If {@code f1} and {@code f2} both represent

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

      *     {@code true}, even though {@code Float.NaN==Float.NaN}

      *     has the value {@code false}.

      * <li>If {@code f1} represents {@code +0.0f} while

      *     {@code f2} represents {@code -0.0f}, or vice

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

      *     {@code false}, even though {@code 0.0f==-0.0f}

      *     has the value {@code true}.

      * </ul>

      *

      * This definition allows hash tables to operate properly.

      *

      * @param obj the object to be compared

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

      *          {@code false} otherwise.

      * @see java.lang.Float#floatToIntBits(float)

      */

     public boolean equals(Object obj) {

         return (obj instanceof Float)

                && (floatToIntBits(((Float)obj).value) == floatToIntBits(value));

     }

     /**

      * Returns a representation of the specified floating-point value

      * according to the IEEE 754 floating-point "single format" bit

      * layout.

      *

      * <p>Bit 31 (the bit that is selected by the mask

      * {@code 0x80000000}) represents the sign of the floating-point

      * number.

      * Bits 30-23 (the bits that are selected by the mask

      * {@code 0x7f800000}) represent the exponent.

      * Bits 22-0 (the bits that are selected by the mask

      * {@code 0x007fffff}) represent the significand (sometimes called

      * the mantissa) of the floating-point number.

      *

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

      * {@code 0x7f800000}.

      *

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

      * {@code 0xff800000}.

      *

      * <p>If the argument is NaN, the result is {@code 0x7fc00000}.

      *

      * <p>In all cases, the result is an integer that, when given to the

      * {@link #intBitsToFloat(int)} method, will produce a floating-point

      * value the same as the argument to {@code floatToIntBits}

      * (except all NaN values are collapsed to a single

      * "canonical" NaN value).

      *

      * @param   value   a floating-point number.

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

      */

     public static int floatToIntBits(float value) {

         int result = floatToRawIntBits(value);

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

         // exponent and nonzero significand.

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

               FloatConsts.EXP_BIT_MASK) &&

              (result & FloatConsts.SIGNIF_BIT_MASK) != 0)

             result = 0x7fc00000;

         return result;

     }

     /**

      * Returns a representation of the specified floating-point value

      * according to the IEEE 754 floating-point "single format" bit

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

      *

      * <p>Bit 31 (the bit that is selected by the mask

      * {@code 0x80000000}) represents the sign of the floating-point

      * number.

      * Bits 30-23 (the bits that are selected by the mask

      * {@code 0x7f800000}) represent the exponent.

      * Bits 22-0 (the bits that are selected by the mask

      * {@code 0x007fffff}) represent the significand (sometimes called

      * the mantissa) of the floating-point number.

      *

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

      * {@code 0x7f800000}.

      *

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

      * {@code 0xff800000}.

      *

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

      * the actual NaN value.  Unlike the {@code floatToIntBits}

      * method, {@code floatToRawIntBits} does not collapse all the

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

      * NaN value.

      *

      * <p>In all cases, the result is an integer that, when given to the

      * {@link #intBitsToFloat(int)} method, will produce a

      * floating-point value the same as the argument to

      * {@code floatToRawIntBits}.

      *

      * @param   value   a floating-point number.

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

      * @since 1.3

      */

     public static native int floatToRawIntBits(float value);

     /**

      * Returns the {@code float} 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

      * "single format" bit layout.

      *

      * <p>If the argument is {@code 0x7f800000}, the result is positive

      * infinity.

      *

      * <p>If the argument is {@code 0xff800000}, the result is negative

      * infinity.

      *

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

      * {@code 0x7f800001} through {@code 0x7fffffff} or in

      * the range {@code 0xff800001} through

      * {@code 0xffffffff}, 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 Float.floatToRawIntBits} 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 >> 31) == 0) ? 1 : -1;

      * int e = ((bits >> 23) & 0xff);

      * int m = (e == 0) ?

      *                 (bits & 0x7fffff) << 1 :

      *                 (bits & 0x7fffff) | 0x800000;

      * </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>-150</sup>.

      *

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

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

      * {@code int} 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 intBitsToFloat} may

      * not be able to return a {@code float} with a signaling NaN

      * bit pattern.  Consequently, for some {@code int} values,

      * {@code floatToRawIntBits(intBitsToFloat(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   an integer.

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

      *          pattern.

      */

     public static native float intBitsToFloat(int bits);

     /**

      * Compares two {@code Float} 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 float} values:

      *

      * <ul><li>

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

      *          be equal to itself and greater than all other

      *          {@code float} values

      *          (including {@code Float.POSITIVE_INFINITY}).

      * <li>

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

      *          than {@code -0.0f}.

      * </ul>

      *

      * This ensures that the <i>natural ordering</i> of {@code Float}

      * objects imposed by this method is <i>consistent with equals</i>.

      *

      * @param   anotherFloat   the {@code Float} to be compared.

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

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

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

      *          is numerically less than {@code anotherFloat};

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

      *          {@code Float} is numerically greater than

      *          {@code anotherFloat}.

      *

      * @since   1.2

      * @see Comparable#compareTo(Object)

      */

     public int compareTo(Float anotherFloat) {

         return Float.compare(value, anotherFloat.value);

     }

     /**

      * Compares the two specified {@code float} 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 Float(f1).compareTo(new Float(f2))

      * </pre>

      *

      * @param   f1        the first {@code float} to compare.

      * @param   f2        the second {@code float} to compare.

      * @return  the value {@code 0} if {@code f1} is

      *          numerically equal to {@code f2}; a value less than

      *          {@code 0} if {@code f1} is numerically less than

      *          {@code f2}; and a value greater than {@code 0}

      *          if {@code f1} is numerically greater than

      *          {@code f2}.

      * @since 1.4

      */

     public static int compare(float f1, float f2) {

         if (f1 < f2)

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

         if (f1 > f2)

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

         // Cannot use floatToRawIntBits because of possibility of NaNs.

         int thisBits    = Float.floatToIntBits(f1);

         int anotherBits = Float.floatToIntBits(f2);

         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 = -2671257302660747028L;

 }