2 * Copyright (c) 1994, 2010, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
28 import org.apidesign.bck2brwsr.core.JavaScriptBody;
31 * The {@code Float} class wraps a value of primitive type
32 * {@code float} in an object. An object of type
33 * {@code Float} contains a single field whose type is
36 * <p>In addition, this class provides several methods for converting a
37 * {@code float} to a {@code String} and a
38 * {@code String} to a {@code float}, as well as other
39 * constants and methods useful when dealing with a
43 * @author Arthur van Hoff
44 * @author Joseph D. Darcy
47 public final class Float extends Number implements Comparable<Float> {
49 * A constant holding the positive infinity of type
50 * {@code float}. It is equal to the value returned by
51 * {@code Float.intBitsToFloat(0x7f800000)}.
53 public static final float POSITIVE_INFINITY = 1.0f / 0.0f;
56 * A constant holding the negative infinity of type
57 * {@code float}. It is equal to the value returned by
58 * {@code Float.intBitsToFloat(0xff800000)}.
60 public static final float NEGATIVE_INFINITY = -1.0f / 0.0f;
63 * A constant holding a Not-a-Number (NaN) value of type
64 * {@code float}. It is equivalent to the value returned by
65 * {@code Float.intBitsToFloat(0x7fc00000)}.
67 public static final float NaN = 0.0f / 0.0f;
70 * A constant holding the largest positive finite value of type
71 * {@code float}, (2-2<sup>-23</sup>)·2<sup>127</sup>.
72 * It is equal to the hexadecimal floating-point literal
73 * {@code 0x1.fffffeP+127f} and also equal to
74 * {@code Float.intBitsToFloat(0x7f7fffff)}.
76 public static final float MAX_VALUE = 0x1.fffffeP+127f; // 3.4028235e+38f
79 * A constant holding the smallest positive normal value of type
80 * {@code float}, 2<sup>-126</sup>. It is equal to the
81 * hexadecimal floating-point literal {@code 0x1.0p-126f} and also
82 * equal to {@code Float.intBitsToFloat(0x00800000)}.
86 public static final float MIN_NORMAL = 0x1.0p-126f; // 1.17549435E-38f
89 * A constant holding the smallest positive nonzero value of type
90 * {@code float}, 2<sup>-149</sup>. It is equal to the
91 * hexadecimal floating-point literal {@code 0x0.000002P-126f}
92 * and also equal to {@code Float.intBitsToFloat(0x1)}.
94 public static final float MIN_VALUE = 0x0.000002P-126f; // 1.4e-45f
97 * Maximum exponent a finite {@code float} variable may have. It
98 * is equal to the value returned by {@code
99 * Math.getExponent(Float.MAX_VALUE)}.
103 public static final int MAX_EXPONENT = 127;
106 * Minimum exponent a normalized {@code float} variable may have.
107 * It is equal to the value returned by {@code
108 * Math.getExponent(Float.MIN_NORMAL)}.
112 public static final int MIN_EXPONENT = -126;
115 * The number of bits used to represent a {@code float} value.
119 public static final int SIZE = 32;
122 * The {@code Class} instance representing the primitive type
127 public static final Class<Float> TYPE = Class.getPrimitiveClass("float");
130 * Returns a string representation of the {@code float}
131 * argument. All characters mentioned below are ASCII characters.
133 * <li>If the argument is NaN, the result is the string
135 * <li>Otherwise, the result is a string that represents the sign and
136 * magnitude (absolute value) of the argument. If the sign is
137 * negative, the first character of the result is
138 * '{@code -}' (<code>'\u002D'</code>); if the sign is
139 * positive, no sign character appears in the result. As for
140 * the magnitude <i>m</i>:
142 * <li>If <i>m</i> is infinity, it is represented by the characters
143 * {@code "Infinity"}; thus, positive infinity produces
144 * the result {@code "Infinity"} and negative infinity
145 * produces the result {@code "-Infinity"}.
146 * <li>If <i>m</i> is zero, it is represented by the characters
147 * {@code "0.0"}; thus, negative zero produces the result
148 * {@code "-0.0"} and positive zero produces the result
150 * <li> If <i>m</i> is greater than or equal to 10<sup>-3</sup> but
151 * less than 10<sup>7</sup>, then it is represented as the
152 * integer part of <i>m</i>, in decimal form with no leading
153 * zeroes, followed by '{@code .}'
154 * (<code>'\u002E'</code>), followed by one or more
155 * decimal digits representing the fractional part of
157 * <li> If <i>m</i> is less than 10<sup>-3</sup> or greater than or
158 * equal to 10<sup>7</sup>, then it is represented in
159 * so-called "computerized scientific notation." Let <i>n</i>
160 * be the unique integer such that 10<sup><i>n</i> </sup>≤
161 * <i>m</i> {@literal <} 10<sup><i>n</i>+1</sup>; then let <i>a</i>
162 * be the mathematically exact quotient of <i>m</i> and
163 * 10<sup><i>n</i></sup> so that 1 ≤ <i>a</i> {@literal <} 10.
164 * The magnitude is then represented as the integer part of
165 * <i>a</i>, as a single decimal digit, followed by
166 * '{@code .}' (<code>'\u002E'</code>), followed by
167 * decimal digits representing the fractional part of
168 * <i>a</i>, followed by the letter '{@code E}'
169 * (<code>'\u0045'</code>), followed by a representation
170 * of <i>n</i> as a decimal integer, as produced by the
171 * method {@link java.lang.Integer#toString(int)}.
175 * How many digits must be printed for the fractional part of
176 * <i>m</i> or <i>a</i>? There must be at least one digit
177 * to represent the fractional part, and beyond that as many, but
178 * only as many, more digits as are needed to uniquely distinguish
179 * the argument value from adjacent values of type
180 * {@code float}. That is, suppose that <i>x</i> is the
181 * exact mathematical value represented by the decimal
182 * representation produced by this method for a finite nonzero
183 * argument <i>f</i>. Then <i>f</i> must be the {@code float}
184 * value nearest to <i>x</i>; or, if two {@code float} values are
185 * equally close to <i>x</i>, then <i>f</i> must be one of
186 * them and the least significant bit of the significand of
187 * <i>f</i> must be {@code 0}.
189 * <p>To create localized string representations of a floating-point
190 * value, use subclasses of {@link java.text.NumberFormat}.
192 * @param f the float to be converted.
193 * @return a string representation of the argument.
195 public static String toString(float f) {
196 return Double.toString(f);
200 * Returns a hexadecimal string representation of the
201 * {@code float} argument. All characters mentioned below are
205 * <li>If the argument is NaN, the result is the string
207 * <li>Otherwise, the result is a string that represents the sign and
208 * magnitude (absolute value) of the argument. If the sign is negative,
209 * the first character of the result is '{@code -}'
210 * (<code>'\u002D'</code>); if the sign is positive, no sign character
211 * appears in the result. As for the magnitude <i>m</i>:
214 * <li>If <i>m</i> is infinity, it is represented by the string
215 * {@code "Infinity"}; thus, positive infinity produces the
216 * result {@code "Infinity"} and negative infinity produces
217 * the result {@code "-Infinity"}.
219 * <li>If <i>m</i> is zero, it is represented by the string
220 * {@code "0x0.0p0"}; thus, negative zero produces the result
221 * {@code "-0x0.0p0"} and positive zero produces the result
224 * <li>If <i>m</i> is a {@code float} value with a
225 * normalized representation, substrings are used to represent the
226 * significand and exponent fields. The significand is
227 * represented by the characters {@code "0x1."}
228 * followed by a lowercase hexadecimal representation of the rest
229 * of the significand as a fraction. Trailing zeros in the
230 * hexadecimal representation are removed unless all the digits
231 * are zero, in which case a single zero is used. Next, the
232 * exponent is represented by {@code "p"} followed
233 * by a decimal string of the unbiased exponent as if produced by
234 * a call to {@link Integer#toString(int) Integer.toString} on the
237 * <li>If <i>m</i> is a {@code float} value with a subnormal
238 * representation, the significand is represented by the
239 * characters {@code "0x0."} followed by a
240 * hexadecimal representation of the rest of the significand as a
241 * fraction. Trailing zeros in the hexadecimal representation are
242 * removed. Next, the exponent is represented by
243 * {@code "p-126"}. Note that there must be at
244 * least one nonzero digit in a subnormal significand.
251 * <caption><h3>Examples</h3></caption>
252 * <tr><th>Floating-point Value</th><th>Hexadecimal String</th>
253 * <tr><td>{@code 1.0}</td> <td>{@code 0x1.0p0}</td>
254 * <tr><td>{@code -1.0}</td> <td>{@code -0x1.0p0}</td>
255 * <tr><td>{@code 2.0}</td> <td>{@code 0x1.0p1}</td>
256 * <tr><td>{@code 3.0}</td> <td>{@code 0x1.8p1}</td>
257 * <tr><td>{@code 0.5}</td> <td>{@code 0x1.0p-1}</td>
258 * <tr><td>{@code 0.25}</td> <td>{@code 0x1.0p-2}</td>
259 * <tr><td>{@code Float.MAX_VALUE}</td>
260 * <td>{@code 0x1.fffffep127}</td>
261 * <tr><td>{@code Minimum Normal Value}</td>
262 * <td>{@code 0x1.0p-126}</td>
263 * <tr><td>{@code Maximum Subnormal Value}</td>
264 * <td>{@code 0x0.fffffep-126}</td>
265 * <tr><td>{@code Float.MIN_VALUE}</td>
266 * <td>{@code 0x0.000002p-126}</td>
268 * @param f the {@code float} to be converted.
269 * @return a hex string representation of the argument.
271 * @author Joseph D. Darcy
273 public static String toHexString(float f) {
274 throw new UnsupportedOperationException();
275 // if (Math.abs(f) < FloatConsts.MIN_NORMAL
276 // && f != 0.0f ) {// float subnormal
277 // // Adjust exponent to create subnormal double, then
278 // // replace subnormal double exponent with subnormal float
280 // String s = Double.toHexString(FpUtils.scalb((double)f,
282 // DoubleConsts.MIN_EXPONENT-
283 // FloatConsts.MIN_EXPONENT));
284 // return s.replaceFirst("p-1022$", "p-126");
286 // else // double string will be the same as float string
287 // return Double.toHexString(f);
291 * Returns a {@code Float} object holding the
292 * {@code float} value represented by the argument string
295 * <p>If {@code s} is {@code null}, then a
296 * {@code NullPointerException} is thrown.
298 * <p>Leading and trailing whitespace characters in {@code s}
299 * are ignored. Whitespace is removed as if by the {@link
300 * String#trim} method; that is, both ASCII space and control
301 * characters are removed. The rest of {@code s} should
302 * constitute a <i>FloatValue</i> as described by the lexical
307 * <dt><i>FloatValue:</i>
308 * <dd><i>Sign<sub>opt</sub></i> {@code NaN}
309 * <dd><i>Sign<sub>opt</sub></i> {@code Infinity}
310 * <dd><i>Sign<sub>opt</sub> FloatingPointLiteral</i>
311 * <dd><i>Sign<sub>opt</sub> HexFloatingPointLiteral</i>
312 * <dd><i>SignedInteger</i>
318 * <dt><i>HexFloatingPointLiteral</i>:
319 * <dd> <i>HexSignificand BinaryExponent FloatTypeSuffix<sub>opt</sub></i>
325 * <dt><i>HexSignificand:</i>
326 * <dd><i>HexNumeral</i>
327 * <dd><i>HexNumeral</i> {@code .}
328 * <dd>{@code 0x} <i>HexDigits<sub>opt</sub>
329 * </i>{@code .}<i> HexDigits</i>
330 * <dd>{@code 0X}<i> HexDigits<sub>opt</sub>
331 * </i>{@code .} <i>HexDigits</i>
337 * <dt><i>BinaryExponent:</i>
338 * <dd><i>BinaryExponentIndicator SignedInteger</i>
344 * <dt><i>BinaryExponentIndicator:</i>
351 * where <i>Sign</i>, <i>FloatingPointLiteral</i>,
352 * <i>HexNumeral</i>, <i>HexDigits</i>, <i>SignedInteger</i> and
353 * <i>FloatTypeSuffix</i> are as defined in the lexical structure
355 * <cite>The Java™ Language Specification</cite>,
356 * except that underscores are not accepted between digits.
357 * If {@code s} does not have the form of
358 * a <i>FloatValue</i>, then a {@code NumberFormatException}
359 * is thrown. Otherwise, {@code s} is regarded as
360 * representing an exact decimal value in the usual
361 * "computerized scientific notation" or as an exact
362 * hexadecimal value; this exact numerical value is then
363 * conceptually converted to an "infinitely precise"
364 * binary value that is then rounded to type {@code float}
365 * by the usual round-to-nearest rule of IEEE 754 floating-point
366 * arithmetic, which includes preserving the sign of a zero
369 * Note that the round-to-nearest rule also implies overflow and
370 * underflow behaviour; if the exact value of {@code s} is large
371 * enough in magnitude (greater than or equal to ({@link
372 * #MAX_VALUE} + {@link Math#ulp(float) ulp(MAX_VALUE)}/2),
373 * rounding to {@code float} will result in an infinity and if the
374 * exact value of {@code s} is small enough in magnitude (less
375 * than or equal to {@link #MIN_VALUE}/2), rounding to float will
378 * Finally, after rounding a {@code Float} object representing
379 * this {@code float} value is returned.
381 * <p>To interpret localized string representations of a
382 * floating-point value, use subclasses of {@link
383 * java.text.NumberFormat}.
385 * <p>Note that trailing format specifiers, specifiers that
386 * determine the type of a floating-point literal
387 * ({@code 1.0f} is a {@code float} value;
388 * {@code 1.0d} is a {@code double} value), do
389 * <em>not</em> influence the results of this method. In other
390 * words, the numerical value of the input string is converted
391 * directly to the target floating-point type. In general, the
392 * two-step sequence of conversions, string to {@code double}
393 * followed by {@code double} to {@code float}, is
394 * <em>not</em> equivalent to converting a string directly to
395 * {@code float}. For example, if first converted to an
396 * intermediate {@code double} and then to
397 * {@code float}, the string<br>
398 * {@code "1.00000017881393421514957253748434595763683319091796875001d"}<br>
399 * results in the {@code float} value
400 * {@code 1.0000002f}; if the string is converted directly to
401 * {@code float}, <code>1.000000<b>1</b>f</code> results.
403 * <p>To avoid calling this method on an invalid string and having
404 * a {@code NumberFormatException} be thrown, the documentation
405 * for {@link Double#valueOf Double.valueOf} lists a regular
406 * expression which can be used to screen the input.
408 * @param s the string to be parsed.
409 * @return a {@code Float} object holding the value
410 * represented by the {@code String} argument.
411 * @throws NumberFormatException if the string does not contain a
414 public static Float valueOf(String s) throws NumberFormatException {
415 throw new UnsupportedOperationException();
416 // return new Float(FloatingDecimal.readJavaFormatString(s).floatValue());
420 * Returns a {@code Float} instance representing the specified
421 * {@code float} value.
422 * If a new {@code Float} instance is not required, this method
423 * should generally be used in preference to the constructor
424 * {@link #Float(float)}, as this method is likely to yield
425 * significantly better space and time performance by caching
426 * frequently requested values.
428 * @param f a float value.
429 * @return a {@code Float} instance representing {@code f}.
432 public static Float valueOf(float f) {
437 * Returns a new {@code float} initialized to the value
438 * represented by the specified {@code String}, as performed
439 * by the {@code valueOf} method of class {@code Float}.
441 * @param s the string to be parsed.
442 * @return the {@code float} value represented by the string
444 * @throws NullPointerException if the string is null
445 * @throws NumberFormatException if the string does not contain a
446 * parsable {@code float}.
447 * @see java.lang.Float#valueOf(String)
450 public static float parseFloat(String s) throws NumberFormatException {
451 throw new UnsupportedOperationException();
452 // return FloatingDecimal.readJavaFormatString(s).floatValue();
456 * Returns {@code true} if the specified number is a
457 * Not-a-Number (NaN) value, {@code false} otherwise.
459 * @param v the value to be tested.
460 * @return {@code true} if the argument is NaN;
461 * {@code false} otherwise.
463 static public boolean isNaN(float v) {
468 * Returns {@code true} if the specified number is infinitely
469 * large in magnitude, {@code false} otherwise.
471 * @param v the value to be tested.
472 * @return {@code true} if the argument is positive infinity or
473 * negative infinity; {@code false} otherwise.
475 static public boolean isInfinite(float v) {
476 return (v == POSITIVE_INFINITY) || (v == NEGATIVE_INFINITY);
480 * The value of the Float.
484 private final float value;
487 * Constructs a newly allocated {@code Float} object that
488 * represents the primitive {@code float} argument.
490 * @param value the value to be represented by the {@code Float}.
492 public Float(float value) {
497 * Constructs a newly allocated {@code Float} object that
498 * represents the argument converted to type {@code float}.
500 * @param value the value to be represented by the {@code Float}.
502 public Float(double value) {
503 this.value = (float)value;
507 * Constructs a newly allocated {@code Float} object that
508 * represents the floating-point value of type {@code float}
509 * represented by the string. The string is converted to a
510 * {@code float} value as if by the {@code valueOf} method.
512 * @param s a string to be converted to a {@code Float}.
513 * @throws NumberFormatException if the string does not contain a
515 * @see java.lang.Float#valueOf(java.lang.String)
517 public Float(String s) throws NumberFormatException {
518 // REMIND: this is inefficient
519 this(valueOf(s).floatValue());
523 * Returns {@code true} if this {@code Float} value is a
524 * Not-a-Number (NaN), {@code false} otherwise.
526 * @return {@code true} if the value represented by this object is
527 * NaN; {@code false} otherwise.
529 public boolean isNaN() {
534 * Returns {@code true} if this {@code Float} value is
535 * infinitely large in magnitude, {@code false} otherwise.
537 * @return {@code true} if the value represented by this object is
538 * positive infinity or negative infinity;
539 * {@code false} otherwise.
541 public boolean isInfinite() {
542 return isInfinite(value);
546 * Returns a string representation of this {@code Float} object.
547 * The primitive {@code float} value represented by this object
548 * is converted to a {@code String} exactly as if by the method
549 * {@code toString} of one argument.
551 * @return a {@code String} representation of this object.
552 * @see java.lang.Float#toString(float)
554 public String toString() {
555 return Float.toString(value);
559 * Returns the value of this {@code Float} as a {@code byte} (by
560 * casting to a {@code byte}).
562 * @return the {@code float} value represented by this object
563 * converted to type {@code byte}
565 public byte byteValue() {
570 * Returns the value of this {@code Float} as a {@code short} (by
571 * casting to a {@code short}).
573 * @return the {@code float} value represented by this object
574 * converted to type {@code short}
577 public short shortValue() {
582 * Returns the value of this {@code Float} as an {@code int} (by
583 * casting to type {@code int}).
585 * @return the {@code float} value represented by this object
586 * converted to type {@code int}
588 public int intValue() {
593 * Returns value of this {@code Float} as a {@code long} (by
594 * casting to type {@code long}).
596 * @return the {@code float} value represented by this object
597 * converted to type {@code long}
599 public long longValue() {
604 * Returns the {@code float} value of this {@code Float} object.
606 * @return the {@code float} value represented by this object
608 public float floatValue() {
613 * Returns the {@code double} value of this {@code Float} object.
615 * @return the {@code float} value represented by this
616 * object is converted to type {@code double} and the
617 * result of the conversion is returned.
619 public double doubleValue() {
620 return (double)value;
624 * Returns a hash code for this {@code Float} object. The
625 * result is the integer bit representation, exactly as produced
626 * by the method {@link #floatToIntBits(float)}, of the primitive
627 * {@code float} value represented by this {@code Float}
630 * @return a hash code value for this object.
632 public int hashCode() {
633 return floatToIntBits(value);
638 * Compares this object against the specified object. The result
639 * is {@code true} if and only if the argument is not
640 * {@code null} and is a {@code Float} object that
641 * represents a {@code float} with the same value as the
642 * {@code float} represented by this object. For this
643 * purpose, two {@code float} values are considered to be the
644 * same if and only if the method {@link #floatToIntBits(float)}
645 * returns the identical {@code int} value when applied to
648 * <p>Note that in most cases, for two instances of class
649 * {@code Float}, {@code f1} and {@code f2}, the value
650 * of {@code f1.equals(f2)} is {@code true} if and only if
653 * f1.floatValue() == f2.floatValue()
654 * </pre></blockquote>
656 * <p>also has the value {@code true}. However, there are two exceptions:
658 * <li>If {@code f1} and {@code f2} both represent
659 * {@code Float.NaN}, then the {@code equals} method returns
660 * {@code true}, even though {@code Float.NaN==Float.NaN}
661 * has the value {@code false}.
662 * <li>If {@code f1} represents {@code +0.0f} while
663 * {@code f2} represents {@code -0.0f}, or vice
664 * versa, the {@code equal} test has the value
665 * {@code false}, even though {@code 0.0f==-0.0f}
666 * has the value {@code true}.
669 * This definition allows hash tables to operate properly.
671 * @param obj the object to be compared
672 * @return {@code true} if the objects are the same;
673 * {@code false} otherwise.
674 * @see java.lang.Float#floatToIntBits(float)
676 public boolean equals(Object obj) {
677 return (obj instanceof Float)
678 && (floatToIntBits(((Float)obj).value) == floatToIntBits(value));
682 * Returns a representation of the specified floating-point value
683 * according to the IEEE 754 floating-point "single format" bit
686 * <p>Bit 31 (the bit that is selected by the mask
687 * {@code 0x80000000}) represents the sign of the floating-point
689 * Bits 30-23 (the bits that are selected by the mask
690 * {@code 0x7f800000}) represent the exponent.
691 * Bits 22-0 (the bits that are selected by the mask
692 * {@code 0x007fffff}) represent the significand (sometimes called
693 * the mantissa) of the floating-point number.
695 * <p>If the argument is positive infinity, the result is
696 * {@code 0x7f800000}.
698 * <p>If the argument is negative infinity, the result is
699 * {@code 0xff800000}.
701 * <p>If the argument is NaN, the result is {@code 0x7fc00000}.
703 * <p>In all cases, the result is an integer that, when given to the
704 * {@link #intBitsToFloat(int)} method, will produce a floating-point
705 * value the same as the argument to {@code floatToIntBits}
706 * (except all NaN values are collapsed to a single
707 * "canonical" NaN value).
709 * @param value a floating-point number.
710 * @return the bits that represent the floating-point number.
712 public static int floatToIntBits(float value) {
713 throw new UnsupportedOperationException();
714 // int result = floatToRawIntBits(value);
715 // // Check for NaN based on values of bit fields, maximum
716 // // exponent and nonzero significand.
717 // if ( ((result & FloatConsts.EXP_BIT_MASK) ==
718 // FloatConsts.EXP_BIT_MASK) &&
719 // (result & FloatConsts.SIGNIF_BIT_MASK) != 0)
720 // result = 0x7fc00000;
725 * Returns a representation of the specified floating-point value
726 * according to the IEEE 754 floating-point "single format" bit
727 * layout, preserving Not-a-Number (NaN) values.
729 * <p>Bit 31 (the bit that is selected by the mask
730 * {@code 0x80000000}) represents the sign of the floating-point
732 * Bits 30-23 (the bits that are selected by the mask
733 * {@code 0x7f800000}) represent the exponent.
734 * Bits 22-0 (the bits that are selected by the mask
735 * {@code 0x007fffff}) represent the significand (sometimes called
736 * the mantissa) of the floating-point number.
738 * <p>If the argument is positive infinity, the result is
739 * {@code 0x7f800000}.
741 * <p>If the argument is negative infinity, the result is
742 * {@code 0xff800000}.
744 * <p>If the argument is NaN, the result is the integer representing
745 * the actual NaN value. Unlike the {@code floatToIntBits}
746 * method, {@code floatToRawIntBits} does not collapse all the
747 * bit patterns encoding a NaN to a single "canonical"
750 * <p>In all cases, the result is an integer that, when given to the
751 * {@link #intBitsToFloat(int)} method, will produce a
752 * floating-point value the same as the argument to
753 * {@code floatToRawIntBits}.
755 * @param value a floating-point number.
756 * @return the bits that represent the floating-point number.
759 public static native int floatToRawIntBits(float value);
762 * Returns the {@code float} value corresponding to a given
763 * bit representation.
764 * The argument is considered to be a representation of a
765 * floating-point value according to the IEEE 754 floating-point
766 * "single format" bit layout.
768 * <p>If the argument is {@code 0x7f800000}, the result is positive
771 * <p>If the argument is {@code 0xff800000}, the result is negative
774 * <p>If the argument is any value in the range
775 * {@code 0x7f800001} through {@code 0x7fffffff} or in
776 * the range {@code 0xff800001} through
777 * {@code 0xffffffff}, the result is a NaN. No IEEE 754
778 * floating-point operation provided by Java can distinguish
779 * between two NaN values of the same type with different bit
780 * patterns. Distinct values of NaN are only distinguishable by
781 * use of the {@code Float.floatToRawIntBits} method.
783 * <p>In all other cases, let <i>s</i>, <i>e</i>, and <i>m</i> be three
784 * values that can be computed from the argument:
787 * int s = ((bits >> 31) == 0) ? 1 : -1;
788 * int e = ((bits >> 23) & 0xff);
790 * (bits & 0x7fffff) << 1 :
791 * (bits & 0x7fffff) | 0x800000;
792 * </pre></blockquote>
794 * Then the floating-point result equals the value of the mathematical
795 * expression <i>s</i>·<i>m</i>·2<sup><i>e</i>-150</sup>.
797 * <p>Note that this method may not be able to return a
798 * {@code float} NaN with exactly same bit pattern as the
799 * {@code int} argument. IEEE 754 distinguishes between two
800 * kinds of NaNs, quiet NaNs and <i>signaling NaNs</i>. The
801 * differences between the two kinds of NaN are generally not
802 * visible in Java. Arithmetic operations on signaling NaNs turn
803 * them into quiet NaNs with a different, but often similar, bit
804 * pattern. However, on some processors merely copying a
805 * signaling NaN also performs that conversion. In particular,
806 * copying a signaling NaN to return it to the calling method may
807 * perform this conversion. So {@code intBitsToFloat} may
808 * not be able to return a {@code float} with a signaling NaN
809 * bit pattern. Consequently, for some {@code int} values,
810 * {@code floatToRawIntBits(intBitsToFloat(start))} may
811 * <i>not</i> equal {@code start}. Moreover, which
812 * particular bit patterns represent signaling NaNs is platform
813 * dependent; although all NaN bit patterns, quiet or signaling,
814 * must be in the NaN range identified above.
816 * @param bits an integer.
817 * @return the {@code float} floating-point value with the same bit
820 @JavaScriptBody(args = "bits",
822 "if (bits === 0x7f800000) return Number.POSITIVE_INFINITY;\n"
823 + "if (bits === 0xff800000) return Number.NEGATIVE_INFINITY;\n"
824 + "if (bits >= 0x7f800001 && bits <= 0xffffffff) return Number.NaN;\n"
825 + "var s = ((bits >> 31) == 0) ? 1 : -1;\n"
826 + "var e = ((bits >> 23) & 0xff);\n"
827 + "var m = (e == 0) ?\n"
828 + " (bits & 0x7fffff) << 1 :\n"
829 + " (bits & 0x7fffff) | 0x800000;\n"
830 + "return s * m * Math.pow(2.0, e - 150);\n"
832 public static native float intBitsToFloat(int bits);
835 * Compares two {@code Float} objects numerically. There are
836 * two ways in which comparisons performed by this method differ
837 * from those performed by the Java language numerical comparison
838 * operators ({@code <, <=, ==, >=, >}) when
839 * applied to primitive {@code float} values:
842 * {@code Float.NaN} is considered by this method to
843 * be equal to itself and greater than all other
844 * {@code float} values
845 * (including {@code Float.POSITIVE_INFINITY}).
847 * {@code 0.0f} is considered by this method to be greater
848 * than {@code -0.0f}.
851 * This ensures that the <i>natural ordering</i> of {@code Float}
852 * objects imposed by this method is <i>consistent with equals</i>.
854 * @param anotherFloat the {@code Float} to be compared.
855 * @return the value {@code 0} if {@code anotherFloat} is
856 * numerically equal to this {@code Float}; a value
857 * less than {@code 0} if this {@code Float}
858 * is numerically less than {@code anotherFloat};
859 * and a value greater than {@code 0} if this
860 * {@code Float} is numerically greater than
861 * {@code anotherFloat}.
864 * @see Comparable#compareTo(Object)
866 public int compareTo(Float anotherFloat) {
867 return Float.compare(value, anotherFloat.value);
871 * Compares the two specified {@code float} values. The sign
872 * of the integer value returned is the same as that of the
873 * integer that would be returned by the call:
875 * new Float(f1).compareTo(new Float(f2))
878 * @param f1 the first {@code float} to compare.
879 * @param f2 the second {@code float} to compare.
880 * @return the value {@code 0} if {@code f1} is
881 * numerically equal to {@code f2}; a value less than
882 * {@code 0} if {@code f1} is numerically less than
883 * {@code f2}; and a value greater than {@code 0}
884 * if {@code f1} is numerically greater than
888 public static int compare(float f1, float f2) {
890 return -1; // Neither val is NaN, thisVal is smaller
892 return 1; // Neither val is NaN, thisVal is larger
894 // Cannot use floatToRawIntBits because of possibility of NaNs.
895 int thisBits = Float.floatToIntBits(f1);
896 int anotherBits = Float.floatToIntBits(f2);
898 return (thisBits == anotherBits ? 0 : // Values are equal
899 (thisBits < anotherBits ? -1 : // (-0.0, 0.0) or (!NaN, NaN)
900 1)); // (0.0, -0.0) or (NaN, !NaN)
903 /** use serialVersionUID from JDK 1.0.2 for interoperability */
904 private static final long serialVersionUID = -2671257302660747028L;