jaroslav@67: /* jaroslav@67: * Copyright (c) 1994, 2010, Oracle and/or its affiliates. All rights reserved. jaroslav@67: * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. jaroslav@67: * jaroslav@67: * This code is free software; you can redistribute it and/or modify it jaroslav@67: * under the terms of the GNU General Public License version 2 only, as jaroslav@67: * published by the Free Software Foundation. Oracle designates this jaroslav@67: * particular file as subject to the "Classpath" exception as provided jaroslav@67: * by Oracle in the LICENSE file that accompanied this code. jaroslav@67: * jaroslav@67: * This code is distributed in the hope that it will be useful, but WITHOUT jaroslav@67: * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or jaroslav@67: * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License jaroslav@67: * version 2 for more details (a copy is included in the LICENSE file that jaroslav@67: * accompanied this code). jaroslav@67: * jaroslav@67: * You should have received a copy of the GNU General Public License version jaroslav@67: * 2 along with this work; if not, write to the Free Software Foundation, jaroslav@67: * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. jaroslav@67: * jaroslav@67: * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA jaroslav@67: * or visit www.oracle.com if you need additional information or have any jaroslav@67: * questions. jaroslav@67: */ jaroslav@67: jaroslav@67: package java.lang; jaroslav@67: jaroslav@116: import org.apidesign.bck2brwsr.core.JavaScriptBody; jaroslav@116: jaroslav@67: /** jaroslav@67: * The {@code Float} class wraps a value of primitive type jaroslav@67: * {@code float} in an object. An object of type jaroslav@67: * {@code Float} contains a single field whose type is jaroslav@67: * {@code float}. jaroslav@67: * jaroslav@67: *
In addition, this class provides several methods for converting a
jaroslav@67: * {@code float} to a {@code String} and a
jaroslav@67: * {@code String} to a {@code float}, as well as other
jaroslav@67: * constants and methods useful when dealing with a
jaroslav@67: * {@code float}.
jaroslav@67: *
jaroslav@67: * @author Lee Boynton
jaroslav@67: * @author Arthur van Hoff
jaroslav@67: * @author Joseph D. Darcy
jaroslav@67: * @since JDK1.0
jaroslav@67: */
jaroslav@67: public final class Float extends Number implements Comparable To create localized string representations of a floating-point
jaroslav@67: * value, use subclasses of {@link java.text.NumberFormat}.
jaroslav@67: *
jaroslav@67: * @param f the float to be converted.
jaroslav@67: * @return a string representation of the argument.
jaroslav@67: */
jaroslav@67: public static String toString(float f) {
jaroslav@187: return Double.toString(f);
jaroslav@67: }
jaroslav@67:
jaroslav@67: /**
jaroslav@67: * Returns a hexadecimal string representation of the
jaroslav@67: * {@code float} argument. All characters mentioned below are
jaroslav@67: * ASCII characters.
jaroslav@67: *
jaroslav@67: * If {@code s} is {@code null}, then a
jaroslav@67: * {@code NullPointerException} is thrown.
jaroslav@67: *
jaroslav@67: * Leading and trailing whitespace characters in {@code s}
jaroslav@67: * are ignored. Whitespace is removed as if by the {@link
jaroslav@67: * String#trim} method; that is, both ASCII space and control
jaroslav@67: * characters are removed. The rest of {@code s} should
jaroslav@67: * constitute a FloatValue as described by the lexical
jaroslav@67: * syntax rules:
jaroslav@67: *
jaroslav@67: *
jaroslav@67: *
jaroslav@67: *
jaroslav@67: *
jaroslav@67: *
jaroslav@67: *
jaroslav@67: *
jaroslav@67: *
jaroslav@67: * To interpret localized string representations of a
jaroslav@67: * floating-point value, use subclasses of {@link
jaroslav@67: * java.text.NumberFormat}.
jaroslav@67: *
jaroslav@67: * Note that trailing format specifiers, specifiers that
jaroslav@67: * determine the type of a floating-point literal
jaroslav@67: * ({@code 1.0f} is a {@code float} value;
jaroslav@67: * {@code 1.0d} is a {@code double} value), do
jaroslav@67: * not influence the results of this method. In other
jaroslav@67: * words, the numerical value of the input string is converted
jaroslav@67: * directly to the target floating-point type. In general, the
jaroslav@67: * two-step sequence of conversions, string to {@code double}
jaroslav@67: * followed by {@code double} to {@code float}, is
jaroslav@67: * not equivalent to converting a string directly to
jaroslav@67: * {@code float}. For example, if first converted to an
jaroslav@67: * intermediate {@code double} and then to
jaroslav@67: * {@code float}, the string To avoid calling this method on an invalid string and having
jaroslav@67: * a {@code NumberFormatException} be thrown, the documentation
jaroslav@67: * for {@link Double#valueOf Double.valueOf} lists a regular
jaroslav@67: * expression which can be used to screen the input.
jaroslav@67: *
jaroslav@67: * @param s the string to be parsed.
jaroslav@67: * @return a {@code Float} object holding the value
jaroslav@67: * represented by the {@code String} argument.
jaroslav@67: * @throws NumberFormatException if the string does not contain a
jaroslav@67: * parsable number.
jaroslav@67: */
jaroslav@67: public static Float valueOf(String s) throws NumberFormatException {
jaroslav@84: throw new UnsupportedOperationException();
jaroslav@84: // return new Float(FloatingDecimal.readJavaFormatString(s).floatValue());
jaroslav@67: }
jaroslav@67:
jaroslav@67: /**
jaroslav@67: * Returns a {@code Float} instance representing the specified
jaroslav@67: * {@code float} value.
jaroslav@67: * If a new {@code Float} instance is not required, this method
jaroslav@67: * should generally be used in preference to the constructor
jaroslav@67: * {@link #Float(float)}, as this method is likely to yield
jaroslav@67: * significantly better space and time performance by caching
jaroslav@67: * frequently requested values.
jaroslav@67: *
jaroslav@67: * @param f a float value.
jaroslav@67: * @return a {@code Float} instance representing {@code f}.
jaroslav@67: * @since 1.5
jaroslav@67: */
jaroslav@67: public static Float valueOf(float f) {
jaroslav@67: return new Float(f);
jaroslav@67: }
jaroslav@67:
jaroslav@67: /**
jaroslav@67: * Returns a new {@code float} initialized to the value
jaroslav@67: * represented by the specified {@code String}, as performed
jaroslav@67: * by the {@code valueOf} method of class {@code Float}.
jaroslav@67: *
jaroslav@67: * @param s the string to be parsed.
jaroslav@67: * @return the {@code float} value represented by the string
jaroslav@67: * argument.
jaroslav@67: * @throws NullPointerException if the string is null
jaroslav@67: * @throws NumberFormatException if the string does not contain a
jaroslav@67: * parsable {@code float}.
jaroslav@67: * @see java.lang.Float#valueOf(String)
jaroslav@67: * @since 1.2
jaroslav@67: */
jaroslav@67: public static float parseFloat(String s) throws NumberFormatException {
jaroslav@84: throw new UnsupportedOperationException();
jaroslav@84: // return FloatingDecimal.readJavaFormatString(s).floatValue();
jaroslav@67: }
jaroslav@67:
jaroslav@67: /**
jaroslav@67: * Returns {@code true} if the specified number is a
jaroslav@67: * Not-a-Number (NaN) value, {@code false} otherwise.
jaroslav@67: *
jaroslav@67: * @param v the value to be tested.
jaroslav@67: * @return {@code true} if the argument is NaN;
jaroslav@67: * {@code false} otherwise.
jaroslav@67: */
jaroslav@67: static public boolean isNaN(float v) {
jaroslav@67: return (v != v);
jaroslav@67: }
jaroslav@67:
jaroslav@67: /**
jaroslav@67: * Returns {@code true} if the specified number is infinitely
jaroslav@67: * large in magnitude, {@code false} otherwise.
jaroslav@67: *
jaroslav@67: * @param v the value to be tested.
jaroslav@67: * @return {@code true} if the argument is positive infinity or
jaroslav@67: * negative infinity; {@code false} otherwise.
jaroslav@67: */
jaroslav@67: static public boolean isInfinite(float v) {
jaroslav@67: return (v == POSITIVE_INFINITY) || (v == NEGATIVE_INFINITY);
jaroslav@67: }
jaroslav@67:
jaroslav@67: /**
jaroslav@67: * The value of the Float.
jaroslav@67: *
jaroslav@67: * @serial
jaroslav@67: */
jaroslav@67: private final float value;
jaroslav@67:
jaroslav@67: /**
jaroslav@67: * Constructs a newly allocated {@code Float} object that
jaroslav@67: * represents the primitive {@code float} argument.
jaroslav@67: *
jaroslav@67: * @param value the value to be represented by the {@code Float}.
jaroslav@67: */
jaroslav@67: public Float(float value) {
jaroslav@67: this.value = value;
jaroslav@67: }
jaroslav@67:
jaroslav@67: /**
jaroslav@67: * Constructs a newly allocated {@code Float} object that
jaroslav@67: * represents the argument converted to type {@code float}.
jaroslav@67: *
jaroslav@67: * @param value the value to be represented by the {@code Float}.
jaroslav@67: */
jaroslav@67: public Float(double value) {
jaroslav@67: this.value = (float)value;
jaroslav@67: }
jaroslav@67:
jaroslav@67: /**
jaroslav@67: * Constructs a newly allocated {@code Float} object that
jaroslav@67: * represents the floating-point value of type {@code float}
jaroslav@67: * represented by the string. The string is converted to a
jaroslav@67: * {@code float} value as if by the {@code valueOf} method.
jaroslav@67: *
jaroslav@67: * @param s a string to be converted to a {@code Float}.
jaroslav@67: * @throws NumberFormatException if the string does not contain a
jaroslav@67: * parsable number.
jaroslav@67: * @see java.lang.Float#valueOf(java.lang.String)
jaroslav@67: */
jaroslav@67: public Float(String s) throws NumberFormatException {
jaroslav@67: // REMIND: this is inefficient
jaroslav@67: this(valueOf(s).floatValue());
jaroslav@67: }
jaroslav@67:
jaroslav@67: /**
jaroslav@67: * Returns {@code true} if this {@code Float} value is a
jaroslav@67: * Not-a-Number (NaN), {@code false} otherwise.
jaroslav@67: *
jaroslav@67: * @return {@code true} if the value represented by this object is
jaroslav@67: * NaN; {@code false} otherwise.
jaroslav@67: */
jaroslav@67: public boolean isNaN() {
jaroslav@67: return isNaN(value);
jaroslav@67: }
jaroslav@67:
jaroslav@67: /**
jaroslav@67: * Returns {@code true} if this {@code Float} value is
jaroslav@67: * infinitely large in magnitude, {@code false} otherwise.
jaroslav@67: *
jaroslav@67: * @return {@code true} if the value represented by this object is
jaroslav@67: * positive infinity or negative infinity;
jaroslav@67: * {@code false} otherwise.
jaroslav@67: */
jaroslav@67: public boolean isInfinite() {
jaroslav@67: return isInfinite(value);
jaroslav@67: }
jaroslav@67:
jaroslav@67: /**
jaroslav@67: * Returns a string representation of this {@code Float} object.
jaroslav@67: * The primitive {@code float} value represented by this object
jaroslav@67: * is converted to a {@code String} exactly as if by the method
jaroslav@67: * {@code toString} of one argument.
jaroslav@67: *
jaroslav@67: * @return a {@code String} representation of this object.
jaroslav@67: * @see java.lang.Float#toString(float)
jaroslav@67: */
jaroslav@67: public String toString() {
jaroslav@67: return Float.toString(value);
jaroslav@67: }
jaroslav@67:
jaroslav@67: /**
jaroslav@67: * Returns the value of this {@code Float} as a {@code byte} (by
jaroslav@67: * casting to a {@code byte}).
jaroslav@67: *
jaroslav@67: * @return the {@code float} value represented by this object
jaroslav@67: * converted to type {@code byte}
jaroslav@67: */
jaroslav@67: public byte byteValue() {
jaroslav@67: return (byte)value;
jaroslav@67: }
jaroslav@67:
jaroslav@67: /**
jaroslav@67: * Returns the value of this {@code Float} as a {@code short} (by
jaroslav@67: * casting to a {@code short}).
jaroslav@67: *
jaroslav@67: * @return the {@code float} value represented by this object
jaroslav@67: * converted to type {@code short}
jaroslav@67: * @since JDK1.1
jaroslav@67: */
jaroslav@67: public short shortValue() {
jaroslav@67: return (short)value;
jaroslav@67: }
jaroslav@67:
jaroslav@67: /**
jaroslav@67: * Returns the value of this {@code Float} as an {@code int} (by
jaroslav@67: * casting to type {@code int}).
jaroslav@67: *
jaroslav@67: * @return the {@code float} value represented by this object
jaroslav@67: * converted to type {@code int}
jaroslav@67: */
jaroslav@67: public int intValue() {
jaroslav@67: return (int)value;
jaroslav@67: }
jaroslav@67:
jaroslav@67: /**
jaroslav@67: * Returns value of this {@code Float} as a {@code long} (by
jaroslav@67: * casting to type {@code long}).
jaroslav@67: *
jaroslav@67: * @return the {@code float} value represented by this object
jaroslav@67: * converted to type {@code long}
jaroslav@67: */
jaroslav@67: public long longValue() {
jaroslav@67: return (long)value;
jaroslav@67: }
jaroslav@67:
jaroslav@67: /**
jaroslav@67: * Returns the {@code float} value of this {@code Float} object.
jaroslav@67: *
jaroslav@67: * @return the {@code float} value represented by this object
jaroslav@67: */
jaroslav@67: public float floatValue() {
jaroslav@67: return value;
jaroslav@67: }
jaroslav@67:
jaroslav@67: /**
jaroslav@67: * Returns the {@code double} value of this {@code Float} object.
jaroslav@67: *
jaroslav@67: * @return the {@code float} value represented by this
jaroslav@67: * object is converted to type {@code double} and the
jaroslav@67: * result of the conversion is returned.
jaroslav@67: */
jaroslav@67: public double doubleValue() {
jaroslav@67: return (double)value;
jaroslav@67: }
jaroslav@67:
jaroslav@67: /**
jaroslav@67: * Returns a hash code for this {@code Float} object. The
jaroslav@67: * result is the integer bit representation, exactly as produced
jaroslav@67: * by the method {@link #floatToIntBits(float)}, of the primitive
jaroslav@67: * {@code float} value represented by this {@code Float}
jaroslav@67: * object.
jaroslav@67: *
jaroslav@67: * @return a hash code value for this object.
jaroslav@67: */
jaroslav@67: public int hashCode() {
jaroslav@67: return floatToIntBits(value);
jaroslav@67: }
jaroslav@67:
jaroslav@67: /**
jaroslav@67:
jaroslav@67: * Compares this object against the specified object. The result
jaroslav@67: * is {@code true} if and only if the argument is not
jaroslav@67: * {@code null} and is a {@code Float} object that
jaroslav@67: * represents a {@code float} with the same value as the
jaroslav@67: * {@code float} represented by this object. For this
jaroslav@67: * purpose, two {@code float} values are considered to be the
jaroslav@67: * same if and only if the method {@link #floatToIntBits(float)}
jaroslav@67: * returns the identical {@code int} value when applied to
jaroslav@67: * each.
jaroslav@67: *
jaroslav@67: * Note that in most cases, for two instances of class
jaroslav@67: * {@code Float}, {@code f1} and {@code f2}, the value
jaroslav@67: * of {@code f1.equals(f2)} is {@code true} if and only if
jaroslav@67: *
jaroslav@67: * also has the value {@code true}. However, there are two exceptions:
jaroslav@67: * Bit 31 (the bit that is selected by the mask
jaroslav@67: * {@code 0x80000000}) represents the sign of the floating-point
jaroslav@67: * number.
jaroslav@67: * Bits 30-23 (the bits that are selected by the mask
jaroslav@67: * {@code 0x7f800000}) represent the exponent.
jaroslav@67: * Bits 22-0 (the bits that are selected by the mask
jaroslav@67: * {@code 0x007fffff}) represent the significand (sometimes called
jaroslav@67: * the mantissa) of the floating-point number.
jaroslav@67: *
jaroslav@67: * If the argument is positive infinity, the result is
jaroslav@67: * {@code 0x7f800000}.
jaroslav@67: *
jaroslav@67: * If the argument is negative infinity, the result is
jaroslav@67: * {@code 0xff800000}.
jaroslav@67: *
jaroslav@67: * If the argument is NaN, the result is {@code 0x7fc00000}.
jaroslav@67: *
jaroslav@67: * In all cases, the result is an integer that, when given to the
jaroslav@67: * {@link #intBitsToFloat(int)} method, will produce a floating-point
jaroslav@67: * value the same as the argument to {@code floatToIntBits}
jaroslav@67: * (except all NaN values are collapsed to a single
jaroslav@67: * "canonical" NaN value).
jaroslav@67: *
jaroslav@67: * @param value a floating-point number.
jaroslav@67: * @return the bits that represent the floating-point number.
jaroslav@67: */
jaroslav@67: public static int floatToIntBits(float value) {
jaroslav@84: throw new UnsupportedOperationException();
jaroslav@84: // int result = floatToRawIntBits(value);
jaroslav@84: // // Check for NaN based on values of bit fields, maximum
jaroslav@84: // // exponent and nonzero significand.
jaroslav@84: // if ( ((result & FloatConsts.EXP_BIT_MASK) ==
jaroslav@84: // FloatConsts.EXP_BIT_MASK) &&
jaroslav@84: // (result & FloatConsts.SIGNIF_BIT_MASK) != 0)
jaroslav@84: // result = 0x7fc00000;
jaroslav@84: // return result;
jaroslav@67: }
jaroslav@67:
jaroslav@67: /**
jaroslav@67: * Returns a representation of the specified floating-point value
jaroslav@67: * according to the IEEE 754 floating-point "single format" bit
jaroslav@67: * layout, preserving Not-a-Number (NaN) values.
jaroslav@67: *
jaroslav@67: * Bit 31 (the bit that is selected by the mask
jaroslav@67: * {@code 0x80000000}) represents the sign of the floating-point
jaroslav@67: * number.
jaroslav@67: * Bits 30-23 (the bits that are selected by the mask
jaroslav@67: * {@code 0x7f800000}) represent the exponent.
jaroslav@67: * Bits 22-0 (the bits that are selected by the mask
jaroslav@67: * {@code 0x007fffff}) represent the significand (sometimes called
jaroslav@67: * the mantissa) of the floating-point number.
jaroslav@67: *
jaroslav@67: * If the argument is positive infinity, the result is
jaroslav@67: * {@code 0x7f800000}.
jaroslav@67: *
jaroslav@67: * If the argument is negative infinity, the result is
jaroslav@67: * {@code 0xff800000}.
jaroslav@67: *
jaroslav@67: * If the argument is NaN, the result is the integer representing
jaroslav@67: * the actual NaN value. Unlike the {@code floatToIntBits}
jaroslav@67: * method, {@code floatToRawIntBits} does not collapse all the
jaroslav@67: * bit patterns encoding a NaN to a single "canonical"
jaroslav@67: * NaN value.
jaroslav@67: *
jaroslav@67: * In all cases, the result is an integer that, when given to the
jaroslav@67: * {@link #intBitsToFloat(int)} method, will produce a
jaroslav@67: * floating-point value the same as the argument to
jaroslav@67: * {@code floatToRawIntBits}.
jaroslav@67: *
jaroslav@67: * @param value a floating-point number.
jaroslav@67: * @return the bits that represent the floating-point number.
jaroslav@67: * @since 1.3
jaroslav@67: */
jaroslav@67: public static native int floatToRawIntBits(float value);
jaroslav@67:
jaroslav@67: /**
jaroslav@67: * Returns the {@code float} value corresponding to a given
jaroslav@67: * bit representation.
jaroslav@67: * The argument is considered to be a representation of a
jaroslav@67: * floating-point value according to the IEEE 754 floating-point
jaroslav@67: * "single format" bit layout.
jaroslav@67: *
jaroslav@67: * If the argument is {@code 0x7f800000}, the result is positive
jaroslav@67: * infinity.
jaroslav@67: *
jaroslav@67: * If the argument is {@code 0xff800000}, the result is negative
jaroslav@67: * infinity.
jaroslav@67: *
jaroslav@67: * If the argument is any value in the range
jaroslav@67: * {@code 0x7f800001} through {@code 0x7fffffff} or in
jaroslav@67: * the range {@code 0xff800001} through
jaroslav@67: * {@code 0xffffffff}, the result is a NaN. No IEEE 754
jaroslav@67: * floating-point operation provided by Java can distinguish
jaroslav@67: * between two NaN values of the same type with different bit
jaroslav@67: * patterns. Distinct values of NaN are only distinguishable by
jaroslav@67: * use of the {@code Float.floatToRawIntBits} method.
jaroslav@67: *
jaroslav@67: * In all other cases, let s, e, and m be three
jaroslav@67: * values that can be computed from the argument:
jaroslav@67: *
jaroslav@67: * Note that this method may not be able to return a
jaroslav@67: * {@code float} NaN with exactly same bit pattern as the
jaroslav@67: * {@code int} argument. IEEE 754 distinguishes between two
jaroslav@67: * kinds of NaNs, quiet NaNs and signaling NaNs. The
jaroslav@67: * differences between the two kinds of NaN are generally not
jaroslav@67: * visible in Java. Arithmetic operations on signaling NaNs turn
jaroslav@67: * them into quiet NaNs with a different, but often similar, bit
jaroslav@67: * pattern. However, on some processors merely copying a
jaroslav@67: * signaling NaN also performs that conversion. In particular,
jaroslav@67: * copying a signaling NaN to return it to the calling method may
jaroslav@67: * perform this conversion. So {@code intBitsToFloat} may
jaroslav@67: * not be able to return a {@code float} with a signaling NaN
jaroslav@67: * bit pattern. Consequently, for some {@code int} values,
jaroslav@67: * {@code floatToRawIntBits(intBitsToFloat(start))} may
jaroslav@67: * not equal {@code start}. Moreover, which
jaroslav@67: * particular bit patterns represent signaling NaNs is platform
jaroslav@67: * dependent; although all NaN bit patterns, quiet or signaling,
jaroslav@67: * must be in the NaN range identified above.
jaroslav@67: *
jaroslav@67: * @param bits an integer.
jaroslav@67: * @return the {@code float} floating-point value with the same bit
jaroslav@67: * pattern.
jaroslav@67: */
jaroslav@181: @JavaScriptBody(args = "bits",
jaroslav@181: body =
lubomir@752: "var s = ((bits >> 31) == 0) ? 1 : -1;\n"
jaroslav@181: + "var e = ((bits >> 23) & 0xff);\n"
lubomir@752: + "if (e === 0xff) {\n"
lubomir@752: + " if ((bits & 0x7fffff) === 0) {\n"
lubomir@752: + " return (s > 0) ? Number.POSITIVE_INFINITY"
lubomir@752: + " : Number.NEGATIVE_INFINITY;\n"
lubomir@752: + " }\n"
lubomir@752: + " return Number.NaN;\n"
lubomir@752: + "}\n"
jaroslav@181: + "var m = (e == 0) ?\n"
jaroslav@181: + " (bits & 0x7fffff) << 1 :\n"
jaroslav@181: + " (bits & 0x7fffff) | 0x800000;\n"
jaroslav@181: + "return s * m * Math.pow(2.0, e - 150);\n"
jaroslav@181: )
jaroslav@67: public static native float intBitsToFloat(int bits);
jaroslav@67:
jaroslav@67: /**
jaroslav@67: * Compares two {@code Float} objects numerically. There are
jaroslav@67: * two ways in which comparisons performed by this method differ
jaroslav@67: * from those performed by the Java language numerical comparison
jaroslav@67: * operators ({@code <, <=, ==, >=, >}) when
jaroslav@67: * applied to primitive {@code float} values:
jaroslav@67: *
jaroslav@67: *
jaroslav@67: *
jaroslav@67: * How many digits must be printed for the fractional part of
jaroslav@67: * m or a? There must be at least one digit
jaroslav@67: * to represent the fractional part, and beyond that as many, but
jaroslav@67: * only as many, more digits as are needed to uniquely distinguish
jaroslav@67: * the argument value from adjacent values of type
jaroslav@67: * {@code float}. That is, suppose that x is the
jaroslav@67: * exact mathematical value represented by the decimal
jaroslav@67: * representation produced by this method for a finite nonzero
jaroslav@67: * argument f. Then f must be the {@code float}
jaroslav@67: * value nearest to x; or, if two {@code float} values are
jaroslav@67: * equally close to x, then f must be one of
jaroslav@67: * them and the least significant bit of the significand of
jaroslav@67: * f must be {@code 0}.
jaroslav@67: *
jaroslav@67: * '\u002D'
); if the sign is
jaroslav@67: * positive, no sign character appears in the result. As for
jaroslav@67: * the magnitude m:
jaroslav@67: *
jaroslav@67: *
jaroslav@67: * '\u002E'
), followed by one or more
jaroslav@67: * decimal digits representing the fractional part of
jaroslav@67: * m.
jaroslav@67: * '\u002E'
), followed by
jaroslav@67: * decimal digits representing the fractional part of
jaroslav@67: * a, followed by the letter '{@code E}'
jaroslav@67: * ('\u0045'
), followed by a representation
jaroslav@67: * of n as a decimal integer, as produced by the
jaroslav@67: * method {@link java.lang.Integer#toString(int)}.
jaroslav@67: *
jaroslav@67: *
jaroslav@67: *
jaroslav@67: *
jaroslav@67: * '\u002D'
); if the sign is positive, no sign character
jaroslav@67: * appears in the result. As for the magnitude m:
jaroslav@67: *
jaroslav@67: *
jaroslav@67: *
jaroslav@67: *
jaroslav@67: *
jaroslav@67: *
jaroslav@67: * @param f the {@code float} to be converted.
jaroslav@67: * @return a hex string representation of the argument.
jaroslav@67: * @since 1.5
jaroslav@67: * @author Joseph D. Darcy
jaroslav@67: */
jaroslav@67: public static String toHexString(float f) {
jaroslav@84: throw new UnsupportedOperationException();
jaroslav@84: // if (Math.abs(f) < FloatConsts.MIN_NORMAL
jaroslav@84: // && f != 0.0f ) {// float subnormal
jaroslav@84: // // Adjust exponent to create subnormal double, then
jaroslav@84: // // replace subnormal double exponent with subnormal float
jaroslav@84: // // exponent
jaroslav@84: // String s = Double.toHexString(FpUtils.scalb((double)f,
jaroslav@84: // /* -1022+126 */
jaroslav@84: // DoubleConsts.MIN_EXPONENT-
jaroslav@84: // FloatConsts.MIN_EXPONENT));
jaroslav@84: // return s.replaceFirst("p-1022$", "p-126");
jaroslav@84: // }
jaroslav@84: // else // double string will be the same as float string
jaroslav@84: // return Double.toHexString(f);
jaroslav@67: }
jaroslav@67:
jaroslav@67: /**
jaroslav@67: * Returns a {@code Float} object holding the
jaroslav@67: * {@code float} value represented by the argument string
jaroslav@67: * {@code s}.
jaroslav@67: *
jaroslav@67: * Examples
Floating-point Value Hexadecimal String
jaroslav@67: * {@code 1.0} {@code 0x1.0p0}
jaroslav@67: * {@code -1.0} {@code -0x1.0p0}
jaroslav@67: * {@code 2.0} {@code 0x1.0p1}
jaroslav@67: * {@code 3.0} {@code 0x1.8p1}
jaroslav@67: * {@code 0.5} {@code 0x1.0p-1}
jaroslav@67: * {@code 0.25} {@code 0x1.0p-2}
jaroslav@67: * {@code Float.MAX_VALUE}
jaroslav@67: * {@code 0x1.fffffep127}
jaroslav@67: * {@code Minimum Normal Value}
jaroslav@67: * {@code 0x1.0p-126}
jaroslav@67: * {@code Maximum Subnormal Value}
jaroslav@67: * {@code 0x0.fffffep-126}
jaroslav@67: * {@code Float.MIN_VALUE}
jaroslav@67: * {@code 0x0.000002p-126}
jaroslav@67: *
jaroslav@67: *
jaroslav@67: *
jaroslav@67: * where Sign, FloatingPointLiteral,
jaroslav@67: * HexNumeral, HexDigits, SignedInteger and
jaroslav@67: * FloatTypeSuffix are as defined in the lexical structure
jaroslav@67: * sections of
jaroslav@67: * The Java™ Language Specification,
jaroslav@67: * except that underscores are not accepted between digits.
jaroslav@67: * If {@code s} does not have the form of
jaroslav@67: * a FloatValue, then a {@code NumberFormatException}
jaroslav@67: * is thrown. Otherwise, {@code s} is regarded as
jaroslav@67: * representing an exact decimal value in the usual
jaroslav@67: * "computerized scientific notation" or as an exact
jaroslav@67: * hexadecimal value; this exact numerical value is then
jaroslav@67: * conceptually converted to an "infinitely precise"
jaroslav@67: * binary value that is then rounded to type {@code float}
jaroslav@67: * by the usual round-to-nearest rule of IEEE 754 floating-point
jaroslav@67: * arithmetic, which includes preserving the sign of a zero
jaroslav@67: * value.
jaroslav@67: *
jaroslav@67: * Note that the round-to-nearest rule also implies overflow and
jaroslav@67: * underflow behaviour; if the exact value of {@code s} is large
jaroslav@67: * enough in magnitude (greater than or equal to ({@link
jaroslav@67: * #MAX_VALUE} + {@link Math#ulp(float) ulp(MAX_VALUE)}/2),
jaroslav@67: * rounding to {@code float} will result in an infinity and if the
jaroslav@67: * exact value of {@code s} is small enough in magnitude (less
jaroslav@67: * than or equal to {@link #MIN_VALUE}/2), rounding to float will
jaroslav@67: * result in a zero.
jaroslav@67: *
jaroslav@67: * Finally, after rounding a {@code Float} object representing
jaroslav@67: * this {@code float} value is returned.
jaroslav@67: *
jaroslav@67: *
jaroslav@67: *
jaroslav@67: *
jaroslav@67: *
jaroslav@67: *
jaroslav@67: *
jaroslav@67: *
jaroslav@67: *
jaroslav@67: *
jaroslav@67: *
jaroslav@67: *
jaroslav@67: *
jaroslav@67: *
jaroslav@67: *
jaroslav@67: *
jaroslav@67: *
jaroslav@67: * {@code "1.00000017881393421514957253748434595763683319091796875001d"}
jaroslav@67: * results in the {@code float} value
jaroslav@67: * {@code 1.0000002f}; if the string is converted directly to
jaroslav@67: * {@code float}, 1.0000001f
results.
jaroslav@67: *
jaroslav@67: *
jaroslav@67: *
jaroslav@67: *
jaroslav@67: * f1.floatValue() == f2.floatValue()
jaroslav@67: *
jaroslav@67: *
jaroslav@67: *
jaroslav@67: * This definition allows hash tables to operate properly.
jaroslav@67: *
jaroslav@67: * @param obj the object to be compared
jaroslav@67: * @return {@code true} if the objects are the same;
jaroslav@67: * {@code false} otherwise.
jaroslav@67: * @see java.lang.Float#floatToIntBits(float)
jaroslav@67: */
jaroslav@67: public boolean equals(Object obj) {
jaroslav@67: return (obj instanceof Float)
jaroslav@67: && (floatToIntBits(((Float)obj).value) == floatToIntBits(value));
jaroslav@67: }
jaroslav@67:
jaroslav@67: /**
jaroslav@67: * Returns a representation of the specified floating-point value
jaroslav@67: * according to the IEEE 754 floating-point "single format" bit
jaroslav@67: * layout.
jaroslav@67: *
jaroslav@67: *
jaroslav@67: *
jaroslav@67: * Then the floating-point result equals the value of the mathematical
jaroslav@67: * expression s·m·2e-150.
jaroslav@67: *
jaroslav@67: *
jaroslav@67: * int s = ((bits >> 31) == 0) ? 1 : -1;
jaroslav@67: * int e = ((bits >> 23) & 0xff);
jaroslav@67: * int m = (e == 0) ?
jaroslav@67: * (bits & 0x7fffff) << 1 :
jaroslav@67: * (bits & 0x7fffff) | 0x800000;
jaroslav@67: *
jaroslav@67: *
jaroslav@67: * This ensures that the natural ordering of {@code Float}
jaroslav@67: * objects imposed by this method is consistent with equals.
jaroslav@67: *
jaroslav@67: * @param anotherFloat the {@code Float} to be compared.
jaroslav@67: * @return the value {@code 0} if {@code anotherFloat} is
jaroslav@67: * numerically equal to this {@code Float}; a value
jaroslav@67: * less than {@code 0} if this {@code Float}
jaroslav@67: * is numerically less than {@code anotherFloat};
jaroslav@67: * and a value greater than {@code 0} if this
jaroslav@67: * {@code Float} is numerically greater than
jaroslav@67: * {@code anotherFloat}.
jaroslav@67: *
jaroslav@67: * @since 1.2
jaroslav@67: * @see Comparable#compareTo(Object)
jaroslav@67: */
jaroslav@67: public int compareTo(Float anotherFloat) {
jaroslav@67: return Float.compare(value, anotherFloat.value);
jaroslav@67: }
jaroslav@67:
jaroslav@67: /**
jaroslav@67: * Compares the two specified {@code float} values. The sign
jaroslav@67: * of the integer value returned is the same as that of the
jaroslav@67: * integer that would be returned by the call:
jaroslav@67: *
jaroslav@67: * new Float(f1).compareTo(new Float(f2))
jaroslav@67: *
jaroslav@67: *
jaroslav@67: * @param f1 the first {@code float} to compare.
jaroslav@67: * @param f2 the second {@code float} to compare.
jaroslav@67: * @return the value {@code 0} if {@code f1} is
jaroslav@67: * numerically equal to {@code f2}; a value less than
jaroslav@67: * {@code 0} if {@code f1} is numerically less than
jaroslav@67: * {@code f2}; and a value greater than {@code 0}
jaroslav@67: * if {@code f1} is numerically greater than
jaroslav@67: * {@code f2}.
jaroslav@67: * @since 1.4
jaroslav@67: */
jaroslav@67: public static int compare(float f1, float f2) {
jaroslav@67: if (f1 < f2)
jaroslav@67: return -1; // Neither val is NaN, thisVal is smaller
jaroslav@67: if (f1 > f2)
jaroslav@67: return 1; // Neither val is NaN, thisVal is larger
jaroslav@67:
jaroslav@67: // Cannot use floatToRawIntBits because of possibility of NaNs.
jaroslav@67: int thisBits = Float.floatToIntBits(f1);
jaroslav@67: int anotherBits = Float.floatToIntBits(f2);
jaroslav@67:
jaroslav@67: return (thisBits == anotherBits ? 0 : // Values are equal
jaroslav@67: (thisBits < anotherBits ? -1 : // (-0.0, 0.0) or (!NaN, NaN)
jaroslav@67: 1)); // (0.0, -0.0) or (NaN, !NaN)
jaroslav@67: }
jaroslav@67:
jaroslav@67: /** use serialVersionUID from JDK 1.0.2 for interoperability */
jaroslav@67: private static final long serialVersionUID = -2671257302660747028L;
jaroslav@67: }