1 /*
2 * Copyright (c) 1994, 2024, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
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.
10 *
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).
16 *
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.
20 *
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
23 * questions.
24 */
25
26 package java.lang;
27
28 import java.lang.invoke.MethodHandles;
29 import java.lang.constant.Constable;
30 import java.lang.constant.ConstantDesc;
31 import java.util.Optional;
32
33 import jdk.internal.math.FloatConsts;
34 import jdk.internal.math.FloatingDecimal;
35 import jdk.internal.math.FloatToDecimal;
36 import jdk.internal.vm.annotation.IntrinsicCandidate;
37
38 /**
39 * The {@code Float} class wraps a value of primitive type
40 * {@code float} in an object. An object of type
41 * {@code Float} contains a single field whose type is
42 * {@code float}.
43 *
44 * <p>In addition, this class provides several methods for converting a
45 * {@code float} to a {@code String} and a
46 * {@code String} to a {@code float}, as well as other
47 * constants and methods useful when dealing with a
48 * {@code float}.
49 *
50 * <p>This is a <a href="{@docRoot}/java.base/java/lang/doc-files/ValueBased.html">value-based</a>
51 * class; programmers should treat instances that are
52 * {@linkplain #equals(Object) equal} as interchangeable and should not
53 * use instances for synchronization, or unpredictable behavior may
54 * occur. For example, in a future release, synchronization may fail.
55 *
56 * <h2><a id=equivalenceRelation>Floating-point Equality, Equivalence,
57 * and Comparison</a></h2>
58 *
59 * The class {@code java.lang.Double} has a {@linkplain
60 * Double##equivalenceRelation discussion of equality,
61 * equivalence, and comparison of floating-point values} that is
62 * equally applicable to {@code float} values.
63 *
64 * <h2><a id=decimalToBinaryConversion>Decimal ↔ Binary Conversion Issues</a></h2>
65 *
66 * The {@linkplain Double##decimalToBinaryConversion discussion of binary to
67 * decimal conversion issues} in {@code java.lang.Double} is also
68 * applicable to {@code float} values.
69 *
70 * @see <a href="https://standards.ieee.org/ieee/754/6210/">
71 * <cite>IEEE Standard for Floating-Point Arithmetic</cite></a>
72 *
73 * @author Lee Boynton
74 * @author Arthur van Hoff
75 * @author Joseph D. Darcy
76 * @since 1.0
77 */
78 @jdk.internal.ValueBased
79 public final class Float extends Number
80 implements Comparable<Float>, Constable, ConstantDesc {
81 /**
82 * A constant holding the positive infinity of type
83 * {@code float}. It is equal to the value returned by
84 * {@code Float.intBitsToFloat(0x7f800000)}.
85 */
86 public static final float POSITIVE_INFINITY = 1.0f / 0.0f;
87
88 /**
89 * A constant holding the negative infinity of type
90 * {@code float}. It is equal to the value returned by
91 * {@code Float.intBitsToFloat(0xff800000)}.
92 */
93 public static final float NEGATIVE_INFINITY = -1.0f / 0.0f;
94
95 /**
96 * A constant holding a Not-a-Number (NaN) value of type
97 * {@code float}. It is equivalent to the value returned by
98 * {@code Float.intBitsToFloat(0x7fc00000)}.
99 */
100 public static final float NaN = 0.0f / 0.0f;
101
102 /**
103 * A constant holding the largest positive finite value of type
104 * {@code float}, (2-2<sup>-23</sup>)·2<sup>127</sup>.
105 * It is equal to the hexadecimal floating-point literal
106 * {@code 0x1.fffffeP+127f} and also equal to
107 * {@code Float.intBitsToFloat(0x7f7fffff)}.
108 */
109 public static final float MAX_VALUE = 0x1.fffffeP+127f; // 3.4028235e+38f
110
111 /**
112 * A constant holding the smallest positive normal value of type
113 * {@code float}, 2<sup>-126</sup>. It is equal to the
114 * hexadecimal floating-point literal {@code 0x1.0p-126f} and also
115 * equal to {@code Float.intBitsToFloat(0x00800000)}.
116 *
117 * @since 1.6
118 */
119 public static final float MIN_NORMAL = 0x1.0p-126f; // 1.17549435E-38f
120
121 /**
122 * A constant holding the smallest positive nonzero value of type
123 * {@code float}, 2<sup>-149</sup>. It is equal to the
124 * hexadecimal floating-point literal {@code 0x0.000002P-126f}
125 * and also equal to {@code Float.intBitsToFloat(0x1)}.
126 */
127 public static final float MIN_VALUE = 0x0.000002P-126f; // 1.4e-45f
128
129 /**
130 * The number of bits used to represent a {@code float} value.
131 *
132 * @since 1.5
133 */
134 public static final int SIZE = 32;
135
136 /**
137 * The number of bits in the significand of a {@code float} value.
138 * This is the parameter N in section {@jls 4.2.3} of
139 * <cite>The Java Language Specification</cite>.
140 *
141 * @since 19
142 */
143 public static final int PRECISION = 24;
144
145 /**
146 * Maximum exponent a finite {@code float} variable may have. It
147 * is equal to the value returned by {@code
148 * Math.getExponent(Float.MAX_VALUE)}.
149 *
150 * @since 1.6
151 */
152 public static final int MAX_EXPONENT = (1 << (SIZE - PRECISION - 1)) - 1; // 127
153
154 /**
155 * Minimum exponent a normalized {@code float} variable may have.
156 * It is equal to the value returned by {@code
157 * Math.getExponent(Float.MIN_NORMAL)}.
158 *
159 * @since 1.6
160 */
161 public static final int MIN_EXPONENT = 1 - MAX_EXPONENT; // -126
162
163 /**
164 * The number of bytes used to represent a {@code float} value.
165 *
166 * @since 1.8
167 */
168 public static final int BYTES = SIZE / Byte.SIZE;
169
170 /**
171 * The {@code Class} instance representing the primitive type
172 * {@code float}.
173 *
174 * @since 1.1
175 */
176 @SuppressWarnings("unchecked")
177 public static final Class<Float> TYPE = (Class<Float>) Class.getPrimitiveClass("float");
178
179 /**
180 * Returns a string representation of the {@code float}
181 * argument. All characters mentioned below are ASCII characters.
182 * <ul>
183 * <li>If the argument is NaN, the result is the string
184 * "{@code NaN}".
185 * <li>Otherwise, the result is a string that represents the sign and
186 * magnitude (absolute value) of the argument. If the sign is
187 * negative, the first character of the result is
188 * '{@code -}' ({@code '\u005Cu002D'}); if the sign is
189 * positive, no sign character appears in the result. As for
190 * the magnitude <i>m</i>:
191 * <ul>
192 * <li>If <i>m</i> is infinity, it is represented by the characters
193 * {@code "Infinity"}; thus, positive infinity produces
194 * the result {@code "Infinity"} and negative infinity
195 * produces the result {@code "-Infinity"}.
196 * <li>If <i>m</i> is zero, it is represented by the characters
197 * {@code "0.0"}; thus, negative zero produces the result
198 * {@code "-0.0"} and positive zero produces the result
199 * {@code "0.0"}.
200 *
201 * <li> Otherwise <i>m</i> is positive and finite.
202 * It is converted to a string in two stages:
203 * <ul>
204 * <li> <em>Selection of a decimal</em>:
205 * A well-defined decimal <i>d</i><sub><i>m</i></sub>
206 * is selected to represent <i>m</i>.
207 * This decimal is (almost always) the <em>shortest</em> one that
208 * rounds to <i>m</i> according to the round to nearest
209 * rounding policy of IEEE 754 floating-point arithmetic.
210 * <li> <em>Formatting as a string</em>:
211 * The decimal <i>d</i><sub><i>m</i></sub> is formatted as a string,
212 * either in plain or in computerized scientific notation,
213 * depending on its value.
214 * </ul>
215 * </ul>
216 * </ul>
217 *
218 * <p>A <em>decimal</em> is a number of the form
219 * <i>s</i>×10<sup><i>i</i></sup>
220 * for some (unique) integers <i>s</i> > 0 and <i>i</i> such that
221 * <i>s</i> is not a multiple of 10.
222 * These integers are the <em>significand</em> and
223 * the <em>exponent</em>, respectively, of the decimal.
224 * The <em>length</em> of the decimal is the (unique)
225 * positive integer <i>n</i> meeting
226 * 10<sup><i>n</i>-1</sup> ≤ <i>s</i> < 10<sup><i>n</i></sup>.
227 *
228 * <p>The decimal <i>d</i><sub><i>m</i></sub> for a finite positive <i>m</i>
229 * is defined as follows:
230 * <ul>
231 * <li>Let <i>R</i> be the set of all decimals that round to <i>m</i>
232 * according to the usual <em>round to nearest</em> rounding policy of
233 * IEEE 754 floating-point arithmetic.
234 * <li>Let <i>p</i> be the minimal length over all decimals in <i>R</i>.
235 * <li>When <i>p</i> ≥ 2, let <i>T</i> be the set of all decimals
236 * in <i>R</i> with length <i>p</i>.
237 * Otherwise, let <i>T</i> be the set of all decimals
238 * in <i>R</i> with length 1 or 2.
239 * <li>Define <i>d</i><sub><i>m</i></sub> as the decimal in <i>T</i>
240 * that is closest to <i>m</i>.
241 * Or if there are two such decimals in <i>T</i>,
242 * select the one with the even significand.
243 * </ul>
244 *
245 * <p>The (uniquely) selected decimal <i>d</i><sub><i>m</i></sub>
246 * is then formatted.
247 * Let <i>s</i>, <i>i</i> and <i>n</i> be the significand, exponent and
248 * length of <i>d</i><sub><i>m</i></sub>, respectively.
249 * Further, let <i>e</i> = <i>n</i> + <i>i</i> - 1 and let
250 * <i>s</i><sub>1</sub>…<i>s</i><sub><i>n</i></sub>
251 * be the usual decimal expansion of <i>s</i>.
252 * Note that <i>s</i><sub>1</sub> ≠ 0
253 * and <i>s</i><sub><i>n</i></sub> ≠ 0.
254 * Below, the decimal point {@code '.'} is {@code '\u005Cu002E'}
255 * and the exponent indicator {@code 'E'} is {@code '\u005Cu0045'}.
256 * <ul>
257 * <li>Case -3 ≤ <i>e</i> < 0:
258 * <i>d</i><sub><i>m</i></sub> is formatted as
259 * <code>0.0</code>…<code>0</code><!--
260 * --><i>s</i><sub>1</sub>…<i>s</i><sub><i>n</i></sub>,
261 * where there are exactly -(<i>n</i> + <i>i</i>) zeroes between
262 * the decimal point and <i>s</i><sub>1</sub>.
263 * For example, 123 × 10<sup>-4</sup> is formatted as
264 * {@code 0.0123}.
265 * <li>Case 0 ≤ <i>e</i> < 7:
266 * <ul>
267 * <li>Subcase <i>i</i> ≥ 0:
268 * <i>d</i><sub><i>m</i></sub> is formatted as
269 * <i>s</i><sub>1</sub>…<i>s</i><sub><i>n</i></sub><!--
270 * --><code>0</code>…<code>0.0</code>,
271 * where there are exactly <i>i</i> zeroes
272 * between <i>s</i><sub><i>n</i></sub> and the decimal point.
273 * For example, 123 × 10<sup>2</sup> is formatted as
274 * {@code 12300.0}.
275 * <li>Subcase <i>i</i> < 0:
276 * <i>d</i><sub><i>m</i></sub> is formatted as
277 * <i>s</i><sub>1</sub>…<!--
278 * --><i>s</i><sub><i>n</i>+<i>i</i></sub><code>.</code><!--
279 * --><i>s</i><sub><i>n</i>+<i>i</i>+1</sub>…<!--
280 * --><i>s</i><sub><i>n</i></sub>,
281 * where there are exactly -<i>i</i> digits to the right of
282 * the decimal point.
283 * For example, 123 × 10<sup>-1</sup> is formatted as
284 * {@code 12.3}.
285 * </ul>
286 * <li>Case <i>e</i> < -3 or <i>e</i> ≥ 7:
287 * computerized scientific notation is used to format
288 * <i>d</i><sub><i>m</i></sub>.
289 * Here <i>e</i> is formatted as by {@link Integer#toString(int)}.
290 * <ul>
291 * <li>Subcase <i>n</i> = 1:
292 * <i>d</i><sub><i>m</i></sub> is formatted as
293 * <i>s</i><sub>1</sub><code>.0E</code><i>e</i>.
294 * For example, 1 × 10<sup>23</sup> is formatted as
295 * {@code 1.0E23}.
296 * <li>Subcase <i>n</i> > 1:
297 * <i>d</i><sub><i>m</i></sub> is formatted as
298 * <i>s</i><sub>1</sub><code>.</code><i>s</i><sub>2</sub><!--
299 * -->…<i>s</i><sub><i>n</i></sub><code>E</code><i>e</i>.
300 * For example, 123 × 10<sup>-21</sup> is formatted as
301 * {@code 1.23E-19}.
302 * </ul>
303 * </ul>
304 *
305 * <p>To create localized string representations of a floating-point
306 * value, use subclasses of {@link java.text.NumberFormat}.
307 *
308 * @param f the {@code float} to be converted.
309 * @return a string representation of the argument.
310 */
311 public static String toString(float f) {
312 return FloatToDecimal.toString(f);
313 }
314
315 /**
316 * Returns a hexadecimal string representation of the
317 * {@code float} argument. All characters mentioned below are
318 * ASCII characters.
319 *
320 * <ul>
321 * <li>If the argument is NaN, the result is the string
322 * "{@code NaN}".
323 * <li>Otherwise, the result is a string that represents the sign and
324 * magnitude (absolute value) of the argument. If the sign is negative,
325 * the first character of the result is '{@code -}'
326 * ({@code '\u005Cu002D'}); if the sign is positive, no sign character
327 * appears in the result. As for the magnitude <i>m</i>:
328 *
329 * <ul>
330 * <li>If <i>m</i> is infinity, it is represented by the string
331 * {@code "Infinity"}; thus, positive infinity produces the
332 * result {@code "Infinity"} and negative infinity produces
333 * the result {@code "-Infinity"}.
334 *
335 * <li>If <i>m</i> is zero, it is represented by the string
336 * {@code "0x0.0p0"}; thus, negative zero produces the result
337 * {@code "-0x0.0p0"} and positive zero produces the result
338 * {@code "0x0.0p0"}.
339 *
340 * <li>If <i>m</i> is a {@code float} value with a
341 * normalized representation, substrings are used to represent the
342 * significand and exponent fields. The significand is
343 * represented by the characters {@code "0x1."}
344 * followed by a lowercase hexadecimal representation of the rest
345 * of the significand as a fraction. Trailing zeros in the
346 * hexadecimal representation are removed unless all the digits
347 * are zero, in which case a single zero is used. Next, the
348 * exponent is represented by {@code "p"} followed
349 * by a decimal string of the unbiased exponent as if produced by
350 * a call to {@link Integer#toString(int) Integer.toString} on the
351 * exponent value.
352 *
353 * <li>If <i>m</i> is a {@code float} value with a subnormal
354 * representation, the significand is represented by the
355 * characters {@code "0x0."} followed by a
356 * hexadecimal representation of the rest of the significand as a
357 * fraction. Trailing zeros in the hexadecimal representation are
358 * removed. Next, the exponent is represented by
359 * {@code "p-126"}. Note that there must be at
360 * least one nonzero digit in a subnormal significand.
361 *
362 * </ul>
363 *
364 * </ul>
365 *
366 * <table class="striped">
367 * <caption>Examples</caption>
368 * <thead>
369 * <tr><th scope="col">Floating-point Value</th><th scope="col">Hexadecimal String</th>
370 * </thead>
371 * <tbody>
372 * <tr><th scope="row">{@code 1.0}</th> <td>{@code 0x1.0p0}</td>
373 * <tr><th scope="row">{@code -1.0}</th> <td>{@code -0x1.0p0}</td>
374 * <tr><th scope="row">{@code 2.0}</th> <td>{@code 0x1.0p1}</td>
375 * <tr><th scope="row">{@code 3.0}</th> <td>{@code 0x1.8p1}</td>
376 * <tr><th scope="row">{@code 0.5}</th> <td>{@code 0x1.0p-1}</td>
377 * <tr><th scope="row">{@code 0.25}</th> <td>{@code 0x1.0p-2}</td>
378 * <tr><th scope="row">{@code Float.MAX_VALUE}</th>
379 * <td>{@code 0x1.fffffep127}</td>
380 * <tr><th scope="row">{@code Minimum Normal Value}</th>
381 * <td>{@code 0x1.0p-126}</td>
382 * <tr><th scope="row">{@code Maximum Subnormal Value}</th>
383 * <td>{@code 0x0.fffffep-126}</td>
384 * <tr><th scope="row">{@code Float.MIN_VALUE}</th>
385 * <td>{@code 0x0.000002p-126}</td>
386 * </tbody>
387 * </table>
388 * @param f the {@code float} to be converted.
389 * @return a hex string representation of the argument.
390 * @since 1.5
391 * @author Joseph D. Darcy
392 */
393 public static String toHexString(float f) {
394 if (Math.abs(f) < Float.MIN_NORMAL
395 && f != 0.0f ) {// float subnormal
396 // Adjust exponent to create subnormal double, then
397 // replace subnormal double exponent with subnormal float
398 // exponent
399 String s = Double.toHexString(Math.scalb((double)f,
400 /* -1022+126 */
401 Double.MIN_EXPONENT-
402 Float.MIN_EXPONENT));
403 return s.replaceFirst("p-1022$", "p-126");
404 }
405 else // double string will be the same as float string
406 return Double.toHexString(f);
407 }
408
409 /**
410 * Returns a {@code Float} object holding the
411 * {@code float} value represented by the argument string
412 * {@code s}.
413 *
414 * <p>If {@code s} is {@code null}, then a
415 * {@code NullPointerException} is thrown.
416 *
417 * <p>Leading and trailing whitespace characters in {@code s}
418 * are ignored. Whitespace is removed as if by the {@link
419 * String#trim} method; that is, both ASCII space and control
420 * characters are removed. The rest of {@code s} should
421 * constitute a <i>FloatValue</i> as described by the lexical
422 * syntax rules:
423 *
424 * <blockquote>
425 * <dl>
426 * <dt><i>FloatValue:</i>
427 * <dd><i>Sign<sub>opt</sub></i> {@code NaN}
428 * <dd><i>Sign<sub>opt</sub></i> {@code Infinity}
429 * <dd><i>Sign<sub>opt</sub> FloatingPointLiteral</i>
430 * <dd><i>Sign<sub>opt</sub> HexFloatingPointLiteral</i>
431 * <dd><i>SignedInteger</i>
432 * </dl>
433 *
434 * <dl>
435 * <dt><i>HexFloatingPointLiteral</i>:
436 * <dd> <i>HexSignificand BinaryExponent FloatTypeSuffix<sub>opt</sub></i>
437 * </dl>
438 *
439 * <dl>
440 * <dt><i>HexSignificand:</i>
441 * <dd><i>HexNumeral</i>
442 * <dd><i>HexNumeral</i> {@code .}
443 * <dd>{@code 0x} <i>HexDigits<sub>opt</sub>
444 * </i>{@code .}<i> HexDigits</i>
445 * <dd>{@code 0X}<i> HexDigits<sub>opt</sub>
446 * </i>{@code .} <i>HexDigits</i>
447 * </dl>
448 *
449 * <dl>
450 * <dt><i>BinaryExponent:</i>
451 * <dd><i>BinaryExponentIndicator SignedInteger</i>
452 * </dl>
453 *
454 * <dl>
455 * <dt><i>BinaryExponentIndicator:</i>
456 * <dd>{@code p}
457 * <dd>{@code P}
458 * </dl>
459 *
460 * </blockquote>
461 *
462 * where <i>Sign</i>, <i>FloatingPointLiteral</i>,
463 * <i>HexNumeral</i>, <i>HexDigits</i>, <i>SignedInteger</i> and
464 * <i>FloatTypeSuffix</i> are as defined in the lexical structure
465 * sections of
466 * <cite>The Java Language Specification</cite>,
467 * except that underscores are not accepted between digits.
468 * If {@code s} does not have the form of
469 * a <i>FloatValue</i>, then a {@code NumberFormatException}
470 * is thrown. Otherwise, {@code s} is regarded as
471 * representing an exact decimal value in the usual
472 * "computerized scientific notation" or as an exact
473 * hexadecimal value; this exact numerical value is then
474 * conceptually converted to an "infinitely precise"
475 * binary value that is then rounded to type {@code float}
476 * by the usual round-to-nearest rule of IEEE 754 floating-point
477 * arithmetic, which includes preserving the sign of a zero
478 * value.
479 *
480 * Note that the round-to-nearest rule also implies overflow and
481 * underflow behaviour; if the exact value of {@code s} is large
482 * enough in magnitude (greater than or equal to ({@link
483 * #MAX_VALUE} + {@link Math#ulp(float) ulp(MAX_VALUE)}/2),
484 * rounding to {@code float} will result in an infinity and if the
485 * exact value of {@code s} is small enough in magnitude (less
486 * than or equal to {@link #MIN_VALUE}/2), rounding to float will
487 * result in a zero.
488 *
489 * Finally, after rounding a {@code Float} object representing
490 * this {@code float} value is returned.
491 *
492 * <p>Note that trailing format specifiers, specifiers that
493 * determine the type of a floating-point literal
494 * ({@code 1.0f} is a {@code float} value;
495 * {@code 1.0d} is a {@code double} value), do
496 * <em>not</em> influence the results of this method. In other
497 * words, the numerical value of the input string is converted
498 * directly to the target floating-point type. In general, the
499 * two-step sequence of conversions, string to {@code double}
500 * followed by {@code double} to {@code float}, is
501 * <em>not</em> equivalent to converting a string directly to
502 * {@code float}. For example, if first converted to an
503 * intermediate {@code double} and then to
504 * {@code float}, the string<br>
505 * {@code "1.00000017881393421514957253748434595763683319091796875001d"}<br>
506 * results in the {@code float} value
507 * {@code 1.0000002f}; if the string is converted directly to
508 * {@code float}, <code>1.000000<b>1</b>f</code> results.
509 *
510 * <p>To avoid calling this method on an invalid string and having
511 * a {@code NumberFormatException} be thrown, the documentation
512 * for {@link Double#valueOf Double.valueOf} lists a regular
513 * expression which can be used to screen the input.
514 *
515 * @apiNote To interpret localized string representations of a
516 * floating-point value, or string representations that have
517 * non-ASCII digits, use {@link java.text.NumberFormat}. For
518 * example,
519 * {@snippet lang="java" :
520 * NumberFormat.getInstance(l).parse(s).floatValue();
521 * }
522 * where {@code l} is the desired locale, or
523 * {@link java.util.Locale#ROOT} if locale insensitive.
524 *
525 * @param s the string to be parsed.
526 * @return a {@code Float} object holding the value
527 * represented by the {@code String} argument.
528 * @throws NumberFormatException if the string does not contain a
529 * parsable number.
530 * @see Double##decimalToBinaryConversion Decimal ↔ Binary Conversion Issues
531 */
532 public static Float valueOf(String s) throws NumberFormatException {
533 return new Float(parseFloat(s));
534 }
535
536 /**
537 * Returns a {@code Float} instance representing the specified
538 * {@code float} value.
539 * If a new {@code Float} instance is not required, this method
540 * should generally be used in preference to the constructor
541 * {@link #Float(float)}, as this method is likely to yield
542 * significantly better space and time performance by caching
543 * frequently requested values.
544 *
545 * @param f a float value.
546 * @return a {@code Float} instance representing {@code f}.
547 * @since 1.5
548 */
549 @IntrinsicCandidate
550 public static Float valueOf(float f) {
551 return new Float(f);
552 }
553
554 /**
555 * Returns a new {@code float} initialized to the value
556 * represented by the specified {@code String}, as performed
557 * by the {@code valueOf} method of class {@code Float}.
558 *
559 * @param s the string to be parsed.
560 * @return the {@code float} value represented by the string
561 * argument.
562 * @throws NullPointerException if the string is null
563 * @throws NumberFormatException if the string does not contain a
564 * parsable {@code float}.
565 * @see java.lang.Float#valueOf(String)
566 * @see Double##decimalToBinaryConversion Decimal ↔ Binary Conversion Issues
567 * @since 1.2
568 */
569 public static float parseFloat(String s) throws NumberFormatException {
570 return FloatingDecimal.parseFloat(s);
571 }
572
573 /**
574 * Returns {@code true} if the specified number is a
575 * Not-a-Number (NaN) value, {@code false} otherwise.
576 *
577 * @apiNote
578 * This method corresponds to the isNaN operation defined in IEEE
579 * 754.
580 *
581 * @param v the value to be tested.
582 * @return {@code true} if the argument is NaN;
583 * {@code false} otherwise.
584 */
585 public static boolean isNaN(float v) {
586 return (v != v);
587 }
588
589 /**
590 * Returns {@code true} if the specified number is infinitely
591 * large in magnitude, {@code false} otherwise.
592 *
593 * @apiNote
594 * This method corresponds to the isInfinite operation defined in
595 * IEEE 754.
596 *
597 * @param v the value to be tested.
598 * @return {@code true} if the argument is positive infinity or
599 * negative infinity; {@code false} otherwise.
600 */
601 @IntrinsicCandidate
602 public static boolean isInfinite(float v) {
603 return Math.abs(v) > MAX_VALUE;
604 }
605
606
607 /**
608 * Returns {@code true} if the argument is a finite floating-point
609 * value; returns {@code false} otherwise (for NaN and infinity
610 * arguments).
611 *
612 * @apiNote
613 * This method corresponds to the isFinite operation defined in
614 * IEEE 754.
615 *
616 * @param f the {@code float} value to be tested
617 * @return {@code true} if the argument is a finite
618 * floating-point value, {@code false} otherwise.
619 * @since 1.8
620 */
621 @IntrinsicCandidate
622 public static boolean isFinite(float f) {
623 return Math.abs(f) <= Float.MAX_VALUE;
624 }
625
626 /**
627 * The value of the Float.
628 *
629 * @serial
630 */
631 private final float value;
632
633 /**
634 * Constructs a newly allocated {@code Float} object that
635 * represents the primitive {@code float} argument.
636 *
637 * @param value the value to be represented by the {@code Float}.
638 *
639 * @deprecated
640 * It is rarely appropriate to use this constructor. The static factory
641 * {@link #valueOf(float)} is generally a better choice, as it is
642 * likely to yield significantly better space and time performance.
643 */
644 @Deprecated(since="9", forRemoval = true)
645 public Float(float value) {
646 this.value = value;
647 }
648
649 /**
650 * Constructs a newly allocated {@code Float} object that
651 * represents the argument converted to type {@code float}.
652 *
653 * @param value the value to be represented by the {@code Float}.
654 *
655 * @deprecated
656 * It is rarely appropriate to use this constructor. Instead, use the
657 * static factory method {@link #valueOf(float)} method as follows:
658 * {@code Float.valueOf((float)value)}.
659 */
660 @Deprecated(since="9", forRemoval = true)
661 public Float(double value) {
662 this.value = (float)value;
663 }
664
665 /**
666 * Constructs a newly allocated {@code Float} object that
667 * represents the floating-point value of type {@code float}
668 * represented by the string. The string is converted to a
669 * {@code float} value as if by the {@code valueOf} method.
670 *
671 * @param s a string to be converted to a {@code Float}.
672 * @throws NumberFormatException if the string does not contain a
673 * parsable number.
674 *
675 * @deprecated
676 * It is rarely appropriate to use this constructor.
677 * Use {@link #parseFloat(String)} to convert a string to a
678 * {@code float} primitive, or use {@link #valueOf(String)}
679 * to convert a string to a {@code Float} object.
680 */
681 @Deprecated(since="9", forRemoval = true)
682 public Float(String s) throws NumberFormatException {
683 value = parseFloat(s);
684 }
685
686 /**
687 * Returns {@code true} if this {@code Float} value is a
688 * Not-a-Number (NaN), {@code false} otherwise.
689 *
690 * @return {@code true} if the value represented by this object is
691 * NaN; {@code false} otherwise.
692 */
693 public boolean isNaN() {
694 return isNaN(value);
695 }
696
697 /**
698 * Returns {@code true} if this {@code Float} value is
699 * infinitely large in magnitude, {@code false} otherwise.
700 *
701 * @return {@code true} if the value represented by this object is
702 * positive infinity or negative infinity;
703 * {@code false} otherwise.
704 */
705 public boolean isInfinite() {
706 return isInfinite(value);
707 }
708
709 /**
710 * Returns a string representation of this {@code Float} object.
711 * The primitive {@code float} value represented by this object
712 * is converted to a {@code String} exactly as if by the method
713 * {@code toString} of one argument.
714 *
715 * @return a {@code String} representation of this object.
716 * @see java.lang.Float#toString(float)
717 */
718 public String toString() {
719 return Float.toString(value);
720 }
721
722 /**
723 * Returns the value of this {@code Float} as a {@code byte} after
724 * a narrowing primitive conversion.
725 *
726 * @return the {@code float} value represented by this object
727 * converted to type {@code byte}
728 * @jls 5.1.3 Narrowing Primitive Conversion
729 */
730 public byte byteValue() {
731 return (byte)value;
732 }
733
734 /**
735 * Returns the value of this {@code Float} as a {@code short}
736 * after a narrowing primitive conversion.
737 *
738 * @return the {@code float} value represented by this object
739 * converted to type {@code short}
740 * @jls 5.1.3 Narrowing Primitive Conversion
741 * @since 1.1
742 */
743 public short shortValue() {
744 return (short)value;
745 }
746
747 /**
748 * Returns the value of this {@code Float} as an {@code int} after
749 * a narrowing primitive conversion.
750 *
751 * @return the {@code float} value represented by this object
752 * converted to type {@code int}
753 * @jls 5.1.3 Narrowing Primitive Conversion
754 */
755 public int intValue() {
756 return (int)value;
757 }
758
759 /**
760 * Returns value of this {@code Float} as a {@code long} after a
761 * narrowing primitive conversion.
762 *
763 * @return the {@code float} value represented by this object
764 * converted to type {@code long}
765 * @jls 5.1.3 Narrowing Primitive Conversion
766 */
767 public long longValue() {
768 return (long)value;
769 }
770
771 /**
772 * Returns the {@code float} value of this {@code Float} object.
773 *
774 * @return the {@code float} value represented by this object
775 */
776 @IntrinsicCandidate
777 public float floatValue() {
778 return value;
779 }
780
781 /**
782 * Returns the value of this {@code Float} as a {@code double}
783 * after a widening primitive conversion.
784 *
785 * @apiNote
786 * This method corresponds to the convertFormat operation defined
787 * in IEEE 754.
788 *
789 * @return the {@code float} value represented by this
790 * object converted to type {@code double}
791 * @jls 5.1.2 Widening Primitive Conversion
792 */
793 public double doubleValue() {
794 return (double)value;
795 }
796
797 /**
798 * Returns a hash code for this {@code Float} object. The
799 * result is the integer bit representation, exactly as produced
800 * by the method {@link #floatToIntBits(float)}, of the primitive
801 * {@code float} value represented by this {@code Float}
802 * object.
803 *
804 * @return a hash code value for this object.
805 */
806 @Override
807 public int hashCode() {
808 return Float.hashCode(value);
809 }
810
811 /**
812 * Returns a hash code for a {@code float} value; compatible with
813 * {@code Float.hashCode()}.
814 *
815 * @param value the value to hash
816 * @return a hash code value for a {@code float} value.
817 * @since 1.8
818 */
819 public static int hashCode(float value) {
820 return floatToIntBits(value);
821 }
822
823 /**
824 * Compares this object against the specified object. The result
825 * is {@code true} if and only if the argument is not
826 * {@code null} and is a {@code Float} object that
827 * represents a {@code float} with the same value as the
828 * {@code float} represented by this object. For this
829 * purpose, two {@code float} values are considered to be the
830 * same if and only if the method {@link #floatToIntBits(float)}
831 * returns the identical {@code int} value when applied to
832 * each.
833 *
834 * @apiNote
835 * This method is defined in terms of {@link
836 * #floatToIntBits(float)} rather than the {@code ==} operator on
837 * {@code float} values since the {@code ==} operator does
838 * <em>not</em> define an equivalence relation and to satisfy the
839 * {@linkplain Object#equals equals contract} an equivalence
840 * relation must be implemented; see <a
841 * href="Double.html#equivalenceRelation">this discussion</a> for
842 * details of floating-point equality and equivalence.
843 *
844 * @param obj the object to be compared
845 * @return {@code true} if the objects are the same;
846 * {@code false} otherwise.
847 * @see java.lang.Float#floatToIntBits(float)
848 * @jls 15.21.1 Numerical Equality Operators == and !=
849 */
850 public boolean equals(Object obj) {
851 return (obj instanceof Float)
852 && (floatToIntBits(((Float)obj).value) == floatToIntBits(value));
853 }
854
855 /**
856 * Returns a representation of the specified floating-point value
857 * according to the IEEE 754 floating-point "single format" bit
858 * layout.
859 *
860 * <p>Bit 31 (the bit that is selected by the mask
861 * {@code 0x80000000}) represents the sign of the floating-point
862 * number.
863 * Bits 30-23 (the bits that are selected by the mask
864 * {@code 0x7f800000}) represent the exponent.
865 * Bits 22-0 (the bits that are selected by the mask
866 * {@code 0x007fffff}) represent the significand (sometimes called
867 * the mantissa) of the floating-point number.
868 *
869 * <p>If the argument is positive infinity, the result is
870 * {@code 0x7f800000}.
871 *
872 * <p>If the argument is negative infinity, the result is
873 * {@code 0xff800000}.
874 *
875 * <p>If the argument is NaN, the result is {@code 0x7fc00000}.
876 *
877 * <p>In all cases, the result is an integer that, when given to the
878 * {@link #intBitsToFloat(int)} method, will produce a floating-point
879 * value the same as the argument to {@code floatToIntBits}
880 * (except all NaN values are collapsed to a single
881 * "canonical" NaN value).
882 *
883 * @param value a floating-point number.
884 * @return the bits that represent the floating-point number.
885 */
886 @IntrinsicCandidate
887 public static int floatToIntBits(float value) {
888 if (!isNaN(value)) {
889 return floatToRawIntBits(value);
890 }
891 return 0x7fc00000;
892 }
893
894 /**
895 * Returns a representation of the specified floating-point value
896 * according to the IEEE 754 floating-point "single format" bit
897 * layout, preserving Not-a-Number (NaN) values.
898 *
899 * <p>Bit 31 (the bit that is selected by the mask
900 * {@code 0x80000000}) represents the sign of the floating-point
901 * number.
902 * Bits 30-23 (the bits that are selected by the mask
903 * {@code 0x7f800000}) represent the exponent.
904 * Bits 22-0 (the bits that are selected by the mask
905 * {@code 0x007fffff}) represent the significand (sometimes called
906 * the mantissa) of the floating-point number.
907 *
908 * <p>If the argument is positive infinity, the result is
909 * {@code 0x7f800000}.
910 *
911 * <p>If the argument is negative infinity, the result is
912 * {@code 0xff800000}.
913 *
914 * <p>If the argument is NaN, the result is the integer representing
915 * the actual NaN value. Unlike the {@code floatToIntBits}
916 * method, {@code floatToRawIntBits} does not collapse all the
917 * bit patterns encoding a NaN to a single "canonical"
918 * NaN value.
919 *
920 * <p>In all cases, the result is an integer that, when given to the
921 * {@link #intBitsToFloat(int)} method, will produce a
922 * floating-point value the same as the argument to
923 * {@code floatToRawIntBits}.
924 *
925 * @param value a floating-point number.
926 * @return the bits that represent the floating-point number.
927 * @since 1.3
928 */
929 @IntrinsicCandidate
930 public static native int floatToRawIntBits(float value);
931
932 /**
933 * Returns the {@code float} value corresponding to a given
934 * bit representation.
935 * The argument is considered to be a representation of a
936 * floating-point value according to the IEEE 754 floating-point
937 * "single format" bit layout.
938 *
939 * <p>If the argument is {@code 0x7f800000}, the result is positive
940 * infinity.
941 *
942 * <p>If the argument is {@code 0xff800000}, the result is negative
943 * infinity.
944 *
945 * <p>If the argument is any value in the range
946 * {@code 0x7f800001} through {@code 0x7fffffff} or in
947 * the range {@code 0xff800001} through
948 * {@code 0xffffffff}, the result is a NaN. No IEEE 754
949 * floating-point operation provided by Java can distinguish
950 * between two NaN values of the same type with different bit
951 * patterns. Distinct values of NaN are only distinguishable by
952 * use of the {@code Float.floatToRawIntBits} method.
953 *
954 * <p>In all other cases, let <i>s</i>, <i>e</i>, and <i>m</i> be three
955 * values that can be computed from the argument:
956 *
957 * {@snippet lang="java" :
958 * int s = ((bits >> 31) == 0) ? 1 : -1;
959 * int e = ((bits >> 23) & 0xff);
960 * int m = (e == 0) ?
961 * (bits & 0x7fffff) << 1 :
962 * (bits & 0x7fffff) | 0x800000;
963 * }
964 *
965 * Then the floating-point result equals the value of the mathematical
966 * expression <i>s</i>·<i>m</i>·2<sup><i>e</i>-150</sup>.
967 *
968 * <p>Note that this method may not be able to return a
969 * {@code float} NaN with exactly same bit pattern as the
970 * {@code int} argument. IEEE 754 distinguishes between two
971 * kinds of NaNs, quiet NaNs and <i>signaling NaNs</i>. The
972 * differences between the two kinds of NaN are generally not
973 * visible in Java. Arithmetic operations on signaling NaNs turn
974 * them into quiet NaNs with a different, but often similar, bit
975 * pattern. However, on some processors merely copying a
976 * signaling NaN also performs that conversion. In particular,
977 * copying a signaling NaN to return it to the calling method may
978 * perform this conversion. So {@code intBitsToFloat} may
979 * not be able to return a {@code float} with a signaling NaN
980 * bit pattern. Consequently, for some {@code int} values,
981 * {@code floatToRawIntBits(intBitsToFloat(start))} may
982 * <i>not</i> equal {@code start}. Moreover, which
983 * particular bit patterns represent signaling NaNs is platform
984 * dependent; although all NaN bit patterns, quiet or signaling,
985 * must be in the NaN range identified above.
986 *
987 * @param bits an integer.
988 * @return the {@code float} floating-point value with the same bit
989 * pattern.
990 */
991 @IntrinsicCandidate
992 public static native float intBitsToFloat(int bits);
993
994 /**
995 * {@return the {@code float} value closest to the numerical value
996 * of the argument, a floating-point binary16 value encoded in a
997 * {@code short}} The conversion is exact; all binary16 values can
998 * be exactly represented in {@code float}.
999 *
1000 * Special cases:
1001 * <ul>
1002 * <li> If the argument is zero, the result is a zero with the
1003 * same sign as the argument.
1004 * <li> If the argument is infinite, the result is an infinity
1005 * with the same sign as the argument.
1006 * <li> If the argument is a NaN, the result is a NaN.
1007 * </ul>
1008 *
1009 * <h4><a id=binary16Format>IEEE 754 binary16 format</a></h4>
1010 * The IEEE 754 standard defines binary16 as a 16-bit format, along
1011 * with the 32-bit binary32 format (corresponding to the {@code
1012 * float} type) and the 64-bit binary64 format (corresponding to
1013 * the {@code double} type). The binary16 format is similar to the
1014 * other IEEE 754 formats, except smaller, having all the usual
1015 * IEEE 754 values such as NaN, signed infinities, signed zeros,
1016 * and subnormals. The parameters (JLS {@jls 4.2.3}) for the
1017 * binary16 format are N = 11 precision bits, K = 5 exponent bits,
1018 * <i>E</i><sub><i>max</i></sub> = 15, and
1019 * <i>E</i><sub><i>min</i></sub> = -14.
1020 *
1021 * @apiNote
1022 * This method corresponds to the convertFormat operation defined
1023 * in IEEE 754 from the binary16 format to the binary32 format.
1024 * The operation of this method is analogous to a primitive
1025 * widening conversion (JLS {@jls 5.1.2}).
1026 *
1027 * @param floatBinary16 the binary16 value to convert to {@code float}
1028 * @since 20
1029 */
1030 @IntrinsicCandidate
1031 public static float float16ToFloat(short floatBinary16) {
1032 /*
1033 * The binary16 format has 1 sign bit, 5 exponent bits, and 10
1034 * significand bits. The exponent bias is 15.
1035 */
1036 int bin16arg = (int)floatBinary16;
1037 int bin16SignBit = 0x8000 & bin16arg;
1038 int bin16ExpBits = 0x7c00 & bin16arg;
1039 int bin16SignifBits = 0x03FF & bin16arg;
1040
1041 // Shift left difference in the number of significand bits in
1042 // the float and binary16 formats
1043 final int SIGNIF_SHIFT = (FloatConsts.SIGNIFICAND_WIDTH - 11);
1044
1045 float sign = (bin16SignBit != 0) ? -1.0f : 1.0f;
1046
1047 // Extract binary16 exponent, remove its bias, add in the bias
1048 // of a float exponent and shift to correct bit location
1049 // (significand width includes the implicit bit so shift one
1050 // less).
1051 int bin16Exp = (bin16ExpBits >> 10) - 15;
1052 if (bin16Exp == -15) {
1053 // For subnormal binary16 values and 0, the numerical
1054 // value is 2^24 * the significand as an integer (no
1055 // implicit bit).
1056 return sign * (0x1p-24f * bin16SignifBits);
1057 } else if (bin16Exp == 16) {
1058 return (bin16SignifBits == 0) ?
1059 sign * Float.POSITIVE_INFINITY :
1060 Float.intBitsToFloat((bin16SignBit << 16) |
1061 0x7f80_0000 |
1062 // Preserve NaN signif bits
1063 ( bin16SignifBits << SIGNIF_SHIFT ));
1064 }
1065
1066 assert -15 < bin16Exp && bin16Exp < 16;
1067
1068 int floatExpBits = (bin16Exp + FloatConsts.EXP_BIAS)
1069 << (FloatConsts.SIGNIFICAND_WIDTH - 1);
1070
1071 // Compute and combine result sign, exponent, and significand bits.
1072 return Float.intBitsToFloat((bin16SignBit << 16) |
1073 floatExpBits |
1074 (bin16SignifBits << SIGNIF_SHIFT));
1075 }
1076
1077 /**
1078 * {@return the floating-point binary16 value, encoded in a {@code
1079 * short}, closest in value to the argument}
1080 * The conversion is computed under the {@linkplain
1081 * java.math.RoundingMode#HALF_EVEN round to nearest even rounding
1082 * mode}.
1083 *
1084 * Special cases:
1085 * <ul>
1086 * <li> If the argument is zero, the result is a zero with the
1087 * same sign as the argument.
1088 * <li> If the argument is infinite, the result is an infinity
1089 * with the same sign as the argument.
1090 * <li> If the argument is a NaN, the result is a NaN.
1091 * </ul>
1092 *
1093 * The <a href="#binary16Format">binary16 format</a> is discussed in
1094 * more detail in the {@link #float16ToFloat} method.
1095 *
1096 * @apiNote
1097 * This method corresponds to the convertFormat operation defined
1098 * in IEEE 754 from the binary32 format to the binary16 format.
1099 * The operation of this method is analogous to a primitive
1100 * narrowing conversion (JLS {@jls 5.1.3}).
1101 *
1102 * @param f the {@code float} value to convert to binary16
1103 * @since 20
1104 */
1105 @IntrinsicCandidate
1106 public static short floatToFloat16(float f) {
1107 int doppel = Float.floatToRawIntBits(f);
1108 short sign_bit = (short)((doppel & 0x8000_0000) >> 16);
1109
1110 if (Float.isNaN(f)) {
1111 // Preserve sign and attempt to preserve significand bits
1112 return (short)(sign_bit
1113 | 0x7c00 // max exponent + 1
1114 // Preserve high order bit of float NaN in the
1115 // binary16 result NaN (tenth bit); OR in remaining
1116 // bits into lower 9 bits of binary 16 significand.
1117 | (doppel & 0x007f_e000) >> 13 // 10 bits
1118 | (doppel & 0x0000_1ff0) >> 4 // 9 bits
1119 | (doppel & 0x0000_000f)); // 4 bits
1120 }
1121
1122 float abs_f = Math.abs(f);
1123
1124 // The overflow threshold is binary16 MAX_VALUE + 1/2 ulp
1125 if (abs_f >= (0x1.ffcp15f + 0x0.002p15f) ) {
1126 return (short)(sign_bit | 0x7c00); // Positive or negative infinity
1127 }
1128
1129 // Smallest magnitude nonzero representable binary16 value
1130 // is equal to 0x1.0p-24; half-way and smaller rounds to zero.
1131 if (abs_f <= 0x1.0p-24f * 0.5f) { // Covers float zeros and subnormals.
1132 return sign_bit; // Positive or negative zero
1133 }
1134
1135 // Dealing with finite values in exponent range of binary16
1136 // (when rounding is done, could still round up)
1137 int exp = Math.getExponent(f);
1138 assert -25 <= exp && exp <= 15;
1139
1140 // For binary16 subnormals, beside forcing exp to -15, retain
1141 // the difference expdelta = E_min - exp. This is the excess
1142 // shift value, in addition to 13, to be used in the
1143 // computations below. Further the (hidden) msb with value 1
1144 // in f must be involved as well.
1145 int expdelta = 0;
1146 int msb = 0x0000_0000;
1147 if (exp < -14) {
1148 expdelta = -14 - exp;
1149 exp = -15;
1150 msb = 0x0080_0000;
1151 }
1152 int f_signif_bits = doppel & 0x007f_ffff | msb;
1153
1154 // Significand bits as if using rounding to zero (truncation).
1155 short signif_bits = (short)(f_signif_bits >> (13 + expdelta));
1156
1157 // For round to nearest even, determining whether or not to
1158 // round up (in magnitude) is a function of the least
1159 // significant bit (LSB), the next bit position (the round
1160 // position), and the sticky bit (whether there are any
1161 // nonzero bits in the exact result to the right of the round
1162 // digit). An increment occurs in three cases:
1163 //
1164 // LSB Round Sticky
1165 // 0 1 1
1166 // 1 1 0
1167 // 1 1 1
1168 // See "Computer Arithmetic Algorithms," Koren, Table 4.9
1169
1170 int lsb = f_signif_bits & (1 << 13 + expdelta);
1171 int round = f_signif_bits & (1 << 12 + expdelta);
1172 int sticky = f_signif_bits & ((1 << 12 + expdelta) - 1);
1173
1174 if (round != 0 && ((lsb | sticky) != 0 )) {
1175 signif_bits++;
1176 }
1177
1178 // No bits set in significand beyond the *first* exponent bit,
1179 // not just the significand; quantity is added to the exponent
1180 // to implement a carry out from rounding the significand.
1181 assert (0xf800 & signif_bits) == 0x0;
1182
1183 return (short)(sign_bit | ( ((exp + 15) << 10) + signif_bits ) );
1184 }
1185
1186 /**
1187 * Compares two {@code Float} objects numerically.
1188 *
1189 * This method imposes a total order on {@code Float} objects
1190 * with two differences compared to the incomplete order defined by
1191 * the Java language numerical comparison operators ({@code <, <=,
1192 * ==, >=, >}) on {@code float} values.
1193 *
1194 * <ul><li> A NaN is <em>unordered</em> with respect to other
1195 * values and unequal to itself under the comparison
1196 * operators. This method chooses to define {@code
1197 * Float.NaN} to be equal to itself and greater than all
1198 * other {@code double} values (including {@code
1199 * Float.POSITIVE_INFINITY}).
1200 *
1201 * <li> Positive zero and negative zero compare equal
1202 * numerically, but are distinct and distinguishable values.
1203 * This method chooses to define positive zero ({@code +0.0f}),
1204 * to be greater than negative zero ({@code -0.0f}).
1205 * </ul>
1206 *
1207 * This ensures that the <i>natural ordering</i> of {@code Float}
1208 * objects imposed by this method is <i>consistent with
1209 * equals</i>; see <a href="Double.html#equivalenceRelation">this
1210 * discussion</a> for details of floating-point comparison and
1211 * ordering.
1212 *
1213 *
1214 * @param anotherFloat the {@code Float} to be compared.
1215 * @return the value {@code 0} if {@code anotherFloat} is
1216 * numerically equal to this {@code Float}; a value
1217 * less than {@code 0} if this {@code Float}
1218 * is numerically less than {@code anotherFloat};
1219 * and a value greater than {@code 0} if this
1220 * {@code Float} is numerically greater than
1221 * {@code anotherFloat}.
1222 *
1223 * @jls 15.20.1 Numerical Comparison Operators {@code <}, {@code <=}, {@code >}, and {@code >=}
1224 * @since 1.2
1225 */
1226 public int compareTo(Float anotherFloat) {
1227 return Float.compare(value, anotherFloat.value);
1228 }
1229
1230 /**
1231 * Compares the two specified {@code float} values. The sign
1232 * of the integer value returned is the same as that of the
1233 * integer that would be returned by the call:
1234 * <pre>
1235 * Float.valueOf(f1).compareTo(Float.valueOf(f2))
1236 * </pre>
1237 *
1238 * @param f1 the first {@code float} to compare.
1239 * @param f2 the second {@code float} to compare.
1240 * @return the value {@code 0} if {@code f1} is
1241 * numerically equal to {@code f2}; a value less than
1242 * {@code 0} if {@code f1} is numerically less than
1243 * {@code f2}; and a value greater than {@code 0}
1244 * if {@code f1} is numerically greater than
1245 * {@code f2}.
1246 * @since 1.4
1247 */
1248 public static int compare(float f1, float f2) {
1249 if (f1 < f2)
1250 return -1; // Neither val is NaN, thisVal is smaller
1251 if (f1 > f2)
1252 return 1; // Neither val is NaN, thisVal is larger
1253
1254 // Cannot use floatToRawIntBits because of possibility of NaNs.
1255 int thisBits = Float.floatToIntBits(f1);
1256 int anotherBits = Float.floatToIntBits(f2);
1257
1258 return (thisBits == anotherBits ? 0 : // Values are equal
1259 (thisBits < anotherBits ? -1 : // (-0.0, 0.0) or (!NaN, NaN)
1260 1)); // (0.0, -0.0) or (NaN, !NaN)
1261 }
1262
1263 /**
1264 * Adds two {@code float} values together as per the + operator.
1265 *
1266 * @apiNote This method corresponds to the addition operation
1267 * defined in IEEE 754.
1268 *
1269 * @param a the first operand
1270 * @param b the second operand
1271 * @return the sum of {@code a} and {@code b}
1272 * @jls 4.2.4 Floating-Point Operations
1273 * @see java.util.function.BinaryOperator
1274 * @since 1.8
1275 */
1276 public static float sum(float a, float b) {
1277 return a + b;
1278 }
1279
1280 /**
1281 * Returns the greater of two {@code float} values
1282 * as if by calling {@link Math#max(float, float) Math.max}.
1283 *
1284 * @apiNote
1285 * This method corresponds to the maximum operation defined in
1286 * IEEE 754.
1287 *
1288 * @param a the first operand
1289 * @param b the second operand
1290 * @return the greater of {@code a} and {@code b}
1291 * @see java.util.function.BinaryOperator
1292 * @since 1.8
1293 */
1294 public static float max(float a, float b) {
1295 return Math.max(a, b);
1296 }
1297
1298 /**
1299 * Returns the smaller of two {@code float} values
1300 * as if by calling {@link Math#min(float, float) Math.min}.
1301 *
1302 * @apiNote
1303 * This method corresponds to the minimum operation defined in
1304 * IEEE 754.
1305 *
1306 * @param a the first operand
1307 * @param b the second operand
1308 * @return the smaller of {@code a} and {@code b}
1309 * @see java.util.function.BinaryOperator
1310 * @since 1.8
1311 */
1312 public static float min(float a, float b) {
1313 return Math.min(a, b);
1314 }
1315
1316 /**
1317 * Returns an {@link Optional} containing the nominal descriptor for this
1318 * instance, which is the instance itself.
1319 *
1320 * @return an {@link Optional} describing the {@linkplain Float} instance
1321 * @since 12
1322 */
1323 @Override
1324 public Optional<Float> describeConstable() {
1325 return Optional.of(this);
1326 }
1327
1328 /**
1329 * Resolves this instance as a {@link ConstantDesc}, the result of which is
1330 * the instance itself.
1331 *
1332 * @param lookup ignored
1333 * @return the {@linkplain Float} instance
1334 * @since 12
1335 */
1336 @Override
1337 public Float resolveConstantDesc(MethodHandles.Lookup lookup) {
1338 return this;
1339 }
1340
1341 /** use serialVersionUID from JDK 1.0.2 for interoperability */
1342 @java.io.Serial
1343 private static final long serialVersionUID = -2671257302660747028L;
1344 }