--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/src/share/classes/java/lang/Float.java Sat Dec 01 00:00:00 2007 +0000
@@ -0,0 +1,878 @@
+/*
+ * Copyright 1994-2006 Sun Microsystems, Inc. All Rights Reserved.
+ * 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. Sun designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Sun 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
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ */
+
+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>)·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>'\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>'\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>≤
+ * <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 ≤ <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>'\u002E'</code>), followed by
+ * decimal digits representing the fractional part of
+ * <i>a</i>, followed by the letter '{@code E}'
+ * (<code>'\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>'\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 the <a
+ * href="http://java.sun.com/docs/books/jls/html/">Java Language
+ * Specification</a>. 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. Finally, 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 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 String.valueOf(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>·<i>m</i>·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
+
+ 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;
+}