1 /*
2 * Copyright (c) 1994, 2017, 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 jdk.internal.math.DoubleToDecimal;
29 import jdk.internal.math.FloatingDecimal;
30 import jdk.internal.math.DoubleConsts;
31 import jdk.internal.HotSpotIntrinsicCandidate;
32
33 /**
34 * The {@code Double} class wraps a value of the primitive type
35 * {@code double} in an object. An object of type
36 * {@code Double} contains a single field whose type is
37 * {@code double}.
38 *
39 * <p>In addition, this class provides several methods for converting a
40 * {@code double} to a {@code String} and a
41 * {@code String} to a {@code double}, as well as other
42 * constants and methods useful when dealing with a
43 * {@code double}.
44 *
45 * @author Lee Boynton
46 * @author Arthur van Hoff
47 * @author Joseph D. Darcy
48 * @since 1.0
49 */
50 public final class Double extends Number implements Comparable<Double> {
51 /**
52 * A constant holding the positive infinity of type
53 * {@code double}. It is equal to the value returned by
54 * {@code Double.longBitsToDouble(0x7ff0000000000000L)}.
55 */
56 public static final double POSITIVE_INFINITY = 1.0 / 0.0;
57
58 /**
59 * A constant holding the negative infinity of type
60 * {@code double}. It is equal to the value returned by
61 * {@code Double.longBitsToDouble(0xfff0000000000000L)}.
62 */
63 public static final double NEGATIVE_INFINITY = -1.0 / 0.0;
64
65 /**
66 * A constant holding a Not-a-Number (NaN) value of type
67 * {@code double}. It is equivalent to the value returned by
68 * {@code Double.longBitsToDouble(0x7ff8000000000000L)}.
69 */
70 public static final double NaN = 0.0d / 0.0;
71
72 /**
73 * A constant holding the largest positive finite value of type
74 * {@code double},
75 * (2-2<sup>-52</sup>)·2<sup>1023</sup>. It is equal to
76 * the hexadecimal floating-point literal
77 * {@code 0x1.fffffffffffffP+1023} and also equal to
78 * {@code Double.longBitsToDouble(0x7fefffffffffffffL)}.
79 */
80 public static final double MAX_VALUE = 0x1.fffffffffffffP+1023; // 1.7976931348623157e+308
81
82 /**
83 * A constant holding the smallest positive normal value of type
84 * {@code double}, 2<sup>-1022</sup>. It is equal to the
85 * hexadecimal floating-point literal {@code 0x1.0p-1022} and also
86 * equal to {@code Double.longBitsToDouble(0x0010000000000000L)}.
87 *
88 * @since 1.6
89 */
90 public static final double MIN_NORMAL = 0x1.0p-1022; // 2.2250738585072014E-308
91
92 /**
93 * A constant holding the smallest positive nonzero value of type
94 * {@code double}, 2<sup>-1074</sup>. It is equal to the
95 * hexadecimal floating-point literal
96 * {@code 0x0.0000000000001P-1022} and also equal to
97 * {@code Double.longBitsToDouble(0x1L)}.
98 */
99 public static final double MIN_VALUE = 0x0.0000000000001P-1022; // 4.9e-324
100
101 /**
102 * Maximum exponent a finite {@code double} variable may have.
103 * It is equal to the value returned by
104 * {@code Math.getExponent(Double.MAX_VALUE)}.
105 *
106 * @since 1.6
107 */
108 public static final int MAX_EXPONENT = 1023;
109
110 /**
111 * Minimum exponent a normalized {@code double} variable may
112 * have. It is equal to the value returned by
113 * {@code Math.getExponent(Double.MIN_NORMAL)}.
114 *
115 * @since 1.6
116 */
117 public static final int MIN_EXPONENT = -1022;
118
119 /**
120 * The number of bits used to represent a {@code double} value.
121 *
122 * @since 1.5
123 */
124 public static final int SIZE = 64;
125
126 /**
127 * The number of bytes used to represent a {@code double} value.
128 *
129 * @since 1.8
130 */
131 public static final int BYTES = SIZE / Byte.SIZE;
132
133 /**
134 * The {@code Class} instance representing the primitive type
135 * {@code double}.
136 *
137 * @since 1.1
138 */
139 @SuppressWarnings("unchecked")
140 public static final Class<Double> TYPE = (Class<Double>) Class.getPrimitiveClass("double");
141
142 /**
143 * Returns a string rendering of the {@code double} argument.
144 *
145 * <p>The characters of the result are all drawn from the ASCII set.
146 * <ul>
147 * <li> Any NaN, whether quiet or signaling, is rendered symbolically
148 * as {@code "NaN"}, regardless of the sign bit.
149 * <li> The infinities +∞ and -∞ are rendered as
150 * {@code "Infinity"} and {@code "-Infinity"}, respectively.
151 * <li> The positive and negative zeroes are rendered as
152 * {@code "0.0"} and {@code "-0.0"}, respectively.
153 * <li> Otherwise {@code v} is finite and non-zero.
154 * It is rendered in two stages:
155 * <ul>
156 * <li> <em>Selection of a decimal</em>: A well-specified non-zero
157 * decimal <i>d</i> is selected to represent {@code v}.
158 * <li> <em>Formatting as a string</em>: The decimal <i>d</i> is
159 * formatted as a string, either in plain or in computerized
160 * scientific notation, depending on its value.
161 * </ul>
162 * </ul>
163 *
164 * <p>The selected decimal <i>d</i> has a length <i>n</i> if it can be
165 * written as <i>d</i> = <i>c</i>·10<sup><i>q</i></sup> for some
166 * integers <i>q</i> and <i>c</i> meeting 10<sup><i>n</i>-1</sup> ≤
167 * |<i>c</i>| < 10<sup><i>n</i></sup>. It has all the following
168 * properties:
169 * <ul>
170 * <li> It rounds to {@code v} according to the usual round-to-closest
171 * rule of IEEE 754 floating-point arithmetic.
172 * <li> Among the decimals above, it has a length of 2 or more.
173 * <li> Among all such decimals, it is one of those with the shortest
174 * length.
175 * <li> Among the latter ones, it is the one closest to {@code v}. Or
176 * if there are two that are equally close to {@code v}, it is the one
177 * whose least significant digit is even.
178 * </ul>
179 * More formally, let <i>d'</i> = <i>c'</i>·10<sup><i>q'</i></sup>
180 * ≠ <i>d</i> be any other decimal that rounds to {@code v} according to
181 * IEEE 754 and of a length <i>n'</i>. Then:
182 * <ul>
183 * <li> either <i>n'</i> = 1, thus <i>d'</i> is too short;
184 * <li> or <i>n'</i> > <i>n</i>, thus <i>d'</i> is too long;
185 * <li> or <i>n'</i> = <i>n</i> and
186 * <ul>
187 * <li> either |<i>d</i> - {@code v}| < |<i>d'</i> - {@code v}|:
188 * thus <i>d'</i> is farther from {@code v};
189 * <li> or |<i>d</i> - {@code v}| = |<i>d'</i> - {@code v}| and
190 * <i>c</i> is even while <i>c'</i> is odd
191 * </ul>
192 * </ul>
193 *
194 * <p>The selected decimal <i>d</i> is then formatted as a string.
195 * If <i>d</i> < 0, the first character of the string is the sign
196 * '{@code -}'. Let |<i>d</i>| = <i>m</i>·10<sup><i>k</i></sup>,
197 * for the unique pair of integer <i>k</i> and real <i>m</i> meeting
198 * 1 ≤ <i>m</i> < 10. Also, let the decimal expansion of <i>m</i> be
199 * <i>m</i><sub>1</sub> . <i>m</i><sub>2</sub> <!--
200 * -->… <i>m</i><sub><i>i</i></sub>,
201 * with <i>i</i> ≥ 1 and <i>m</i><sub><i>i</i></sub> ≠ 0.
202 * <ul>
203 * <li>Case -3 ≤ k < 0: |<i>d</i>| is formatted as
204 * 0 . 0…0<i>m</i><sub>1</sub>…<!--
205 * --><i>m</i><sub><i>i</i></sub>,
206 * where there are exactly -<i>k</i> leading zeroes before
207 * <i>m</i><sub>1</sub>, including the zero to the left of the
208 * decimal point; for example, {@code "0.01234"}.
209 * <li>Case 0 ≤ <i>k</i> < 7:
210 * <ul>
211 * <li>Subcase <i>i</i> < <i>k</i> + 2:
212 * |<i>d</i>| is formatted as
213 * <i>m</i><sub>1</sub>…<!--
214 * --><i>m</i><sub><i>i</i></sub>0…0 . 0,
215 * where there are exactly <i>k</i> + 2 - <i>i</i> trailing zeroes
216 * after <i>m</i><sub><i>i</i></sub>, including the zero to the
217 * right of the decimal point; for example, {@code "1200.0"}.
218 * <li>Subcase <i>i</i> ≥ <i>k</i> + 2:
219 * |<i>d</i>| is formatted as <i>m</i><sub>1</sub>…<!--
220 * --><i>m</i><sub><i>k</i>+1</sub> . <!--
221 * --><i>m</i><sub><i>k</i>+2</sub>…<!--
222 * --><i>m</i><sub><i>i</i></sub>; for example, {@code "1234.32"}.
223 * </ul>
224 * <li>Case <i>k</i> < -3 or <i>k</i> ≥ 7:
225 * computerized scientific notation is used to format |<i>d</i>|,
226 * by combining <i>m</i> and <i>k</i> separated by the exponent
227 * indicator '{@code E}'. The exponent <i>k</i> is formatted as in
228 * {@link Integer#toString(int)}.
229 * <ul>
230 * <li>Subcase <i>i</i> = 1: |<i>d</i>| is formatted as
231 * <i>m</i><sub>1</sub> . 0E<i>k</i>;
232 * for example, {@code "2.0E23"}.
233 * <li>Subcase <i>i</i> > 1: |<i>d</i>| is formatted as
234 * <i>m</i><sub>1</sub> . <i>m</i><sub>2</sub><!--
235 * -->…<i>m</i><sub><i>i</i></sub>E<i>k</i>;
236 * for example, {@code "1.234E-32"}.
237 * </ul>
238 * </ul>
239 *
240 * @param v the {@code double} to be rendered.
241 * @return a string rendering of the argument.
242 */
243 public static String toString(double v) {
244 return DoubleToDecimal.toString(v);
245 }
246
247 /**
248 * Returns a hexadecimal string representation of the
249 * {@code double} argument. All characters mentioned below
250 * are ASCII characters.
251 *
252 * <ul>
253 * <li>If the argument is NaN, the result is the string
254 * "{@code NaN}".
255 * <li>Otherwise, the result is a string that represents the sign
256 * and magnitude of the argument. If the sign is negative, the
257 * first character of the result is '{@code -}'
258 * ({@code '\u005Cu002D'}); if the sign is positive, no sign
259 * character appears in the result. As for the magnitude <i>m</i>:
260 *
261 * <ul>
262 * <li>If <i>m</i> is infinity, it is represented by the string
263 * {@code "Infinity"}; thus, positive infinity produces the
264 * result {@code "Infinity"} and negative infinity produces
265 * the result {@code "-Infinity"}.
266 *
267 * <li>If <i>m</i> is zero, it is represented by the string
268 * {@code "0x0.0p0"}; thus, negative zero produces the result
269 * {@code "-0x0.0p0"} and positive zero produces the result
270 * {@code "0x0.0p0"}.
271 *
272 * <li>If <i>m</i> is a {@code double} value with a
273 * normalized representation, substrings are used to represent the
274 * significand and exponent fields. The significand is
275 * represented by the characters {@code "0x1."}
276 * followed by a lowercase hexadecimal representation of the rest
277 * of the significand as a fraction. Trailing zeros in the
278 * hexadecimal representation are removed unless all the digits
279 * are zero, in which case a single zero is used. Next, the
280 * exponent is represented by {@code "p"} followed
281 * by a decimal string of the unbiased exponent as if produced by
282 * a call to {@link Integer#toString(int) Integer.toString} on the
283 * exponent value.
284 *
285 * <li>If <i>m</i> is a {@code double} value with a subnormal
286 * representation, the significand is represented by the
287 * characters {@code "0x0."} followed by a
288 * hexadecimal representation of the rest of the significand as a
289 * fraction. Trailing zeros in the hexadecimal representation are
290 * removed. Next, the exponent is represented by
291 * {@code "p-1022"}. Note that there must be at
292 * least one nonzero digit in a subnormal significand.
293 *
294 * </ul>
295 *
296 * </ul>
297 *
298 * <table class="striped">
299 * <caption>Examples</caption>
300 * <thead>
301 * <tr><th scope="col">Floating-point Value</th><th scope="col">Hexadecimal String</th>
302 * </thead>
303 * <tbody style="text-align:right">
304 * <tr><th scope="row">{@code 1.0}</th> <td>{@code 0x1.0p0}</td>
305 * <tr><th scope="row">{@code -1.0}</th> <td>{@code -0x1.0p0}</td>
306 * <tr><th scope="row">{@code 2.0}</th> <td>{@code 0x1.0p1}</td>
307 * <tr><th scope="row">{@code 3.0}</th> <td>{@code 0x1.8p1}</td>
308 * <tr><th scope="row">{@code 0.5}</th> <td>{@code 0x1.0p-1}</td>
309 * <tr><th scope="row">{@code 0.25}</th> <td>{@code 0x1.0p-2}</td>
310 * <tr><th scope="row">{@code Double.MAX_VALUE}</th>
311 * <td>{@code 0x1.fffffffffffffp1023}</td>
312 * <tr><th scope="row">{@code Minimum Normal Value}</th>
313 * <td>{@code 0x1.0p-1022}</td>
314 * <tr><th scope="row">{@code Maximum Subnormal Value}</th>
315 * <td>{@code 0x0.fffffffffffffp-1022}</td>
316 * <tr><th scope="row">{@code Double.MIN_VALUE}</th>
317 * <td>{@code 0x0.0000000000001p-1022}</td>
318 * </tbody>
319 * </table>
320 * @param d the {@code double} to be converted.
321 * @return a hex string representation of the argument.
322 * @since 1.5
323 * @author Joseph D. Darcy
324 */
325 public static String toHexString(double d) {
326 /*
327 * Modeled after the "a" conversion specifier in C99, section
328 * 7.19.6.1; however, the output of this method is more
329 * tightly specified.
330 */
331 if (!isFinite(d) )
332 // For infinity and NaN, use the decimal output.
333 return Double.toString(d);
334 else {
335 // Initialized to maximum size of output.
336 StringBuilder answer = new StringBuilder(24);
337
338 if (Math.copySign(1.0, d) == -1.0) // value is negative,
339 answer.append("-"); // so append sign info
340
341 answer.append("0x");
342
343 d = Math.abs(d);
344
345 if(d == 0.0) {
346 answer.append("0.0p0");
347 } else {
348 boolean subnormal = (d < Double.MIN_NORMAL);
349
350 // Isolate significand bits and OR in a high-order bit
351 // so that the string representation has a known
352 // length.
353 long signifBits = (Double.doubleToLongBits(d)
354 & DoubleConsts.SIGNIF_BIT_MASK) |
355 0x1000000000000000L;
356
357 // Subnormal values have a 0 implicit bit; normal
358 // values have a 1 implicit bit.
359 answer.append(subnormal ? "0." : "1.");
360
361 // Isolate the low-order 13 digits of the hex
362 // representation. If all the digits are zero,
363 // replace with a single 0; otherwise, remove all
364 // trailing zeros.
365 String signif = Long.toHexString(signifBits).substring(3,16);
366 answer.append(signif.equals("0000000000000") ? // 13 zeros
367 "0":
368 signif.replaceFirst("0{1,12}$", ""));
369
370 answer.append('p');
371 // If the value is subnormal, use the E_min exponent
372 // value for double; otherwise, extract and report d's
373 // exponent (the representation of a subnormal uses
374 // E_min -1).
375 answer.append(subnormal ?
376 Double.MIN_EXPONENT:
377 Math.getExponent(d));
378 }
379 return answer.toString();
380 }
381 }
382
383 /**
384 * Returns a {@code Double} object holding the
385 * {@code double} value represented by the argument string
386 * {@code s}.
387 *
388 * <p>If {@code s} is {@code null}, then a
389 * {@code NullPointerException} is thrown.
390 *
391 * <p>Leading and trailing whitespace characters in {@code s}
392 * are ignored. Whitespace is removed as if by the {@link
393 * String#trim} method; that is, both ASCII space and control
394 * characters are removed. The rest of {@code s} should
395 * constitute a <i>FloatValue</i> as described by the lexical
396 * syntax rules:
397 *
398 * <blockquote>
399 * <dl>
400 * <dt><i>FloatValue:</i>
401 * <dd><i>Sign<sub>opt</sub></i> {@code NaN}
402 * <dd><i>Sign<sub>opt</sub></i> {@code Infinity}
403 * <dd><i>Sign<sub>opt</sub> FloatingPointLiteral</i>
404 * <dd><i>Sign<sub>opt</sub> HexFloatingPointLiteral</i>
405 * <dd><i>SignedInteger</i>
406 * </dl>
407 *
408 * <dl>
409 * <dt><i>HexFloatingPointLiteral</i>:
410 * <dd> <i>HexSignificand BinaryExponent FloatTypeSuffix<sub>opt</sub></i>
411 * </dl>
412 *
413 * <dl>
414 * <dt><i>HexSignificand:</i>
415 * <dd><i>HexNumeral</i>
416 * <dd><i>HexNumeral</i> {@code .}
417 * <dd>{@code 0x} <i>HexDigits<sub>opt</sub>
418 * </i>{@code .}<i> HexDigits</i>
419 * <dd>{@code 0X}<i> HexDigits<sub>opt</sub>
420 * </i>{@code .} <i>HexDigits</i>
421 * </dl>
422 *
423 * <dl>
424 * <dt><i>BinaryExponent:</i>
425 * <dd><i>BinaryExponentIndicator SignedInteger</i>
426 * </dl>
427 *
428 * <dl>
429 * <dt><i>BinaryExponentIndicator:</i>
430 * <dd>{@code p}
431 * <dd>{@code P}
432 * </dl>
433 *
434 * </blockquote>
435 *
436 * where <i>Sign</i>, <i>FloatingPointLiteral</i>,
437 * <i>HexNumeral</i>, <i>HexDigits</i>, <i>SignedInteger</i> and
438 * <i>FloatTypeSuffix</i> are as defined in the lexical structure
439 * sections of
440 * <cite>The Java™ Language Specification</cite>,
441 * except that underscores are not accepted between digits.
442 * If {@code s} does not have the form of
443 * a <i>FloatValue</i>, then a {@code NumberFormatException}
444 * is thrown. Otherwise, {@code s} is regarded as
445 * representing an exact decimal value in the usual
446 * "computerized scientific notation" or as an exact
447 * hexadecimal value; this exact numerical value is then
448 * conceptually converted to an "infinitely precise"
449 * binary value that is then rounded to type {@code double}
450 * by the usual round-to-nearest rule of IEEE 754 floating-point
451 * arithmetic, which includes preserving the sign of a zero
452 * value.
453 *
454 * Note that the round-to-nearest rule also implies overflow and
455 * underflow behaviour; if the exact value of {@code s} is large
456 * enough in magnitude (greater than or equal to ({@link
457 * #MAX_VALUE} + {@link Math#ulp(double) ulp(MAX_VALUE)}/2),
458 * rounding to {@code double} will result in an infinity and if the
459 * exact value of {@code s} is small enough in magnitude (less
460 * than or equal to {@link #MIN_VALUE}/2), rounding to float will
461 * result in a zero.
462 *
463 * Finally, after rounding a {@code Double} object representing
464 * this {@code double} value is returned.
465 *
466 * <p> To interpret localized string representations of a
467 * floating-point value, use subclasses of {@link
468 * java.text.NumberFormat}.
469 *
470 * <p>Note that trailing format specifiers, specifiers that
471 * determine the type of a floating-point literal
472 * ({@code 1.0f} is a {@code float} value;
473 * {@code 1.0d} is a {@code double} value), do
474 * <em>not</em> influence the results of this method. In other
475 * words, the numerical value of the input string is converted
476 * directly to the target floating-point type. The two-step
477 * sequence of conversions, string to {@code float} followed
478 * by {@code float} to {@code double}, is <em>not</em>
479 * equivalent to converting a string directly to
480 * {@code double}. For example, the {@code float}
481 * literal {@code 0.1f} is equal to the {@code double}
482 * value {@code 0.10000000149011612}; the {@code float}
483 * literal {@code 0.1f} represents a different numerical
484 * value than the {@code double} literal
485 * {@code 0.1}. (The numerical value 0.1 cannot be exactly
486 * represented in a binary floating-point number.)
487 *
488 * <p>To avoid calling this method on an invalid string and having
489 * a {@code NumberFormatException} be thrown, the regular
490 * expression below can be used to screen the input string:
491 *
492 * <pre>{@code
493 * final String Digits = "(\\p{Digit}+)";
494 * final String HexDigits = "(\\p{XDigit}+)";
495 * // an exponent is 'e' or 'E' followed by an optionally
496 * // signed decimal integer.
497 * final String Exp = "[eE][+-]?"+Digits;
498 * final String fpRegex =
499 * ("[\\x00-\\x20]*"+ // Optional leading "whitespace"
500 * "[+-]?(" + // Optional sign character
501 * "NaN|" + // "NaN" string
502 * "Infinity|" + // "Infinity" string
503 *
504 * // A decimal floating-point string representing a finite positive
505 * // number without a leading sign has at most five basic pieces:
506 * // Digits . Digits ExponentPart FloatTypeSuffix
507 * //
508 * // Since this method allows integer-only strings as input
509 * // in addition to strings of floating-point literals, the
510 * // two sub-patterns below are simplifications of the grammar
511 * // productions from section 3.10.2 of
512 * // The Java Language Specification.
513 *
514 * // Digits ._opt Digits_opt ExponentPart_opt FloatTypeSuffix_opt
515 * "((("+Digits+"(\\.)?("+Digits+"?)("+Exp+")?)|"+
516 *
517 * // . Digits ExponentPart_opt FloatTypeSuffix_opt
518 * "(\\.("+Digits+")("+Exp+")?)|"+
519 *
520 * // Hexadecimal strings
521 * "((" +
522 * // 0[xX] HexDigits ._opt BinaryExponent FloatTypeSuffix_opt
523 * "(0[xX]" + HexDigits + "(\\.)?)|" +
524 *
525 * // 0[xX] HexDigits_opt . HexDigits BinaryExponent FloatTypeSuffix_opt
526 * "(0[xX]" + HexDigits + "?(\\.)" + HexDigits + ")" +
527 *
528 * ")[pP][+-]?" + Digits + "))" +
529 * "[fFdD]?))" +
530 * "[\\x00-\\x20]*");// Optional trailing "whitespace"
531 *
532 * if (Pattern.matches(fpRegex, myString))
533 * Double.valueOf(myString); // Will not throw NumberFormatException
534 * else {
535 * // Perform suitable alternative action
536 * }
537 * }</pre>
538 *
539 * @param s the string to be parsed.
540 * @return a {@code Double} object holding the value
541 * represented by the {@code String} argument.
542 * @throws NumberFormatException if the string does not contain a
543 * parsable number.
544 */
545 public static Double valueOf(String s) throws NumberFormatException {
546 return new Double(parseDouble(s));
547 }
548
549 /**
550 * Returns a {@code Double} instance representing the specified
551 * {@code double} value.
552 * If a new {@code Double} instance is not required, this method
553 * should generally be used in preference to the constructor
554 * {@link #Double(double)}, as this method is likely to yield
555 * significantly better space and time performance by caching
556 * frequently requested values.
557 *
558 * @param d a double value.
559 * @return a {@code Double} instance representing {@code d}.
560 * @since 1.5
561 */
562 @HotSpotIntrinsicCandidate
563 public static Double valueOf(double d) {
564 return new Double(d);
565 }
566
567 /**
568 * Returns a new {@code double} initialized to the value
569 * represented by the specified {@code String}, as performed
570 * by the {@code valueOf} method of class
571 * {@code Double}.
572 *
573 * @param s the string to be parsed.
574 * @return the {@code double} value represented by the string
575 * argument.
576 * @throws NullPointerException if the string is null
577 * @throws NumberFormatException if the string does not contain
578 * a parsable {@code double}.
579 * @see java.lang.Double#valueOf(String)
580 * @since 1.2
581 */
582 public static double parseDouble(String s) throws NumberFormatException {
583 return FloatingDecimal.parseDouble(s);
584 }
585
586 /**
587 * Returns {@code true} if the specified number is a
588 * Not-a-Number (NaN) value, {@code false} otherwise.
589 *
590 * @param v the value to be tested.
591 * @return {@code true} if the value of the argument is NaN;
592 * {@code false} otherwise.
593 */
594 public static boolean isNaN(double v) {
595 return (v != v);
596 }
597
598 /**
599 * Returns {@code true} if the specified number is infinitely
600 * large in magnitude, {@code false} otherwise.
601 *
602 * @param v the value to be tested.
603 * @return {@code true} if the value of the argument is positive
604 * infinity or negative infinity; {@code false} otherwise.
605 */
606 public static boolean isInfinite(double v) {
607 return (v == POSITIVE_INFINITY) || (v == NEGATIVE_INFINITY);
608 }
609
610 /**
611 * Returns {@code true} if the argument is a finite floating-point
612 * value; returns {@code false} otherwise (for NaN and infinity
613 * arguments).
614 *
615 * @param d the {@code double} value to be tested
616 * @return {@code true} if the argument is a finite
617 * floating-point value, {@code false} otherwise.
618 * @since 1.8
619 */
620 public static boolean isFinite(double d) {
621 return Math.abs(d) <= Double.MAX_VALUE;
622 }
623
624 /**
625 * The value of the Double.
626 *
627 * @serial
628 */
629 private final double value;
630
631 /**
632 * Constructs a newly allocated {@code Double} object that
633 * represents the primitive {@code double} argument.
634 *
635 * @param value the value to be represented by the {@code Double}.
636 *
637 * @deprecated
638 * It is rarely appropriate to use this constructor. The static factory
639 * {@link #valueOf(double)} is generally a better choice, as it is
640 * likely to yield significantly better space and time performance.
641 */
642 @Deprecated(since="9")
643 public Double(double value) {
644 this.value = value;
645 }
646
647 /**
648 * Constructs a newly allocated {@code Double} object that
649 * represents the floating-point value of type {@code double}
650 * represented by the string. The string is converted to a
651 * {@code double} value as if by the {@code valueOf} method.
652 *
653 * @param s a string to be converted to a {@code Double}.
654 * @throws NumberFormatException if the string does not contain a
655 * parsable number.
656 *
657 * @deprecated
658 * It is rarely appropriate to use this constructor.
659 * Use {@link #parseDouble(String)} to convert a string to a
660 * {@code double} primitive, or use {@link #valueOf(String)}
661 * to convert a string to a {@code Double} object.
662 */
663 @Deprecated(since="9")
664 public Double(String s) throws NumberFormatException {
665 value = parseDouble(s);
666 }
667
668 /**
669 * Returns {@code true} if this {@code Double} value is
670 * a Not-a-Number (NaN), {@code false} otherwise.
671 *
672 * @return {@code true} if the value represented by this object is
673 * NaN; {@code false} otherwise.
674 */
675 public boolean isNaN() {
676 return isNaN(value);
677 }
678
679 /**
680 * Returns {@code true} if this {@code Double} value is
681 * infinitely large in magnitude, {@code false} otherwise.
682 *
683 * @return {@code true} if the value represented by this object is
684 * positive infinity or negative infinity;
685 * {@code false} otherwise.
686 */
687 public boolean isInfinite() {
688 return isInfinite(value);
689 }
690
691 /**
692 * Returns a string representation of this {@code Double} object.
693 * The primitive {@code double} value represented by this
694 * object is converted to a string exactly as if by the method
695 * {@code toString} of one argument.
696 *
697 * @return a {@code String} representation of this object.
698 * @see java.lang.Double#toString(double)
699 */
700 public String toString() {
701 return toString(value);
702 }
703
704 /**
705 * Returns the value of this {@code Double} as a {@code byte}
706 * after a narrowing primitive conversion.
707 *
708 * @return the {@code double} value represented by this object
709 * converted to type {@code byte}
710 * @jls 5.1.3 Narrowing Primitive Conversions
711 * @since 1.1
712 */
713 public byte byteValue() {
714 return (byte)value;
715 }
716
717 /**
718 * Returns the value of this {@code Double} as a {@code short}
719 * after a narrowing primitive conversion.
720 *
721 * @return the {@code double} value represented by this object
722 * converted to type {@code short}
723 * @jls 5.1.3 Narrowing Primitive Conversions
724 * @since 1.1
725 */
726 public short shortValue() {
727 return (short)value;
728 }
729
730 /**
731 * Returns the value of this {@code Double} as an {@code int}
732 * after a narrowing primitive conversion.
733 * @jls 5.1.3 Narrowing Primitive Conversions
734 *
735 * @return the {@code double} value represented by this object
736 * converted to type {@code int}
737 */
738 public int intValue() {
739 return (int)value;
740 }
741
742 /**
743 * Returns the value of this {@code Double} as a {@code long}
744 * after a narrowing primitive conversion.
745 *
746 * @return the {@code double} value represented by this object
747 * converted to type {@code long}
748 * @jls 5.1.3 Narrowing Primitive Conversions
749 */
750 public long longValue() {
751 return (long)value;
752 }
753
754 /**
755 * Returns the value of this {@code Double} as a {@code float}
756 * after a narrowing primitive conversion.
757 *
758 * @return the {@code double} value represented by this object
759 * converted to type {@code float}
760 * @jls 5.1.3 Narrowing Primitive Conversions
761 * @since 1.0
762 */
763 public float floatValue() {
764 return (float)value;
765 }
766
767 /**
768 * Returns the {@code double} value of this {@code Double} object.
769 *
770 * @return the {@code double} value represented by this object
771 */
772 @HotSpotIntrinsicCandidate
773 public double doubleValue() {
774 return value;
775 }
776
777 /**
778 * Returns a hash code for this {@code Double} object. The
779 * result is the exclusive OR of the two halves of the
780 * {@code long} integer bit representation, exactly as
781 * produced by the method {@link #doubleToLongBits(double)}, of
782 * the primitive {@code double} value represented by this
783 * {@code Double} object. That is, the hash code is the value
784 * of the expression:
785 *
786 * <blockquote>
787 * {@code (int)(v^(v>>>32))}
788 * </blockquote>
789 *
790 * where {@code v} is defined by:
791 *
792 * <blockquote>
793 * {@code long v = Double.doubleToLongBits(this.doubleValue());}
794 * </blockquote>
795 *
796 * @return a {@code hash code} value for this object.
797 */
798 @Override
799 public int hashCode() {
800 return Double.hashCode(value);
801 }
802
803 /**
804 * Returns a hash code for a {@code double} value; compatible with
805 * {@code Double.hashCode()}.
806 *
807 * @param value the value to hash
808 * @return a hash code value for a {@code double} value.
809 * @since 1.8
810 */
811 public static int hashCode(double value) {
812 long bits = doubleToLongBits(value);
813 return (int)(bits ^ (bits >>> 32));
814 }
815
816 /**
817 * Compares this object against the specified object. The result
818 * is {@code true} if and only if the argument is not
819 * {@code null} and is a {@code Double} object that
820 * represents a {@code double} that has the same value as the
821 * {@code double} represented by this object. For this
822 * purpose, two {@code double} values are considered to be
823 * the same if and only if the method {@link
824 * #doubleToLongBits(double)} returns the identical
825 * {@code long} value when applied to each.
826 *
827 * <p>Note that in most cases, for two instances of class
828 * {@code Double}, {@code d1} and {@code d2}, the
829 * value of {@code d1.equals(d2)} is {@code true} if and
830 * only if
831 *
832 * <blockquote>
833 * {@code d1.doubleValue() == d2.doubleValue()}
834 * </blockquote>
835 *
836 * <p>also has the value {@code true}. However, there are two
837 * exceptions:
838 * <ul>
839 * <li>If {@code d1} and {@code d2} both represent
840 * {@code Double.NaN}, then the {@code equals} method
841 * returns {@code true}, even though
842 * {@code Double.NaN==Double.NaN} has the value
843 * {@code false}.
844 * <li>If {@code d1} represents {@code +0.0} while
845 * {@code d2} represents {@code -0.0}, or vice versa,
846 * the {@code equal} test has the value {@code false},
847 * even though {@code +0.0==-0.0} has the value {@code true}.
848 * </ul>
849 * This definition allows hash tables to operate properly.
850 * @param obj the object to compare with.
851 * @return {@code true} if the objects are the same;
852 * {@code false} otherwise.
853 * @see java.lang.Double#doubleToLongBits(double)
854 */
855 public boolean equals(Object obj) {
856 return (obj instanceof Double)
857 && (doubleToLongBits(((Double)obj).value) ==
858 doubleToLongBits(value));
859 }
860
861 /**
862 * Returns a representation of the specified floating-point value
863 * according to the IEEE 754 floating-point "double
864 * format" bit layout.
865 *
866 * <p>Bit 63 (the bit that is selected by the mask
867 * {@code 0x8000000000000000L}) represents the sign of the
868 * floating-point number. Bits
869 * 62-52 (the bits that are selected by the mask
870 * {@code 0x7ff0000000000000L}) represent the exponent. Bits 51-0
871 * (the bits that are selected by the mask
872 * {@code 0x000fffffffffffffL}) represent the significand
873 * (sometimes called the mantissa) of the floating-point number.
874 *
875 * <p>If the argument is positive infinity, the result is
876 * {@code 0x7ff0000000000000L}.
877 *
878 * <p>If the argument is negative infinity, the result is
879 * {@code 0xfff0000000000000L}.
880 *
881 * <p>If the argument is NaN, the result is
882 * {@code 0x7ff8000000000000L}.
883 *
884 * <p>In all cases, the result is a {@code long} integer that, when
885 * given to the {@link #longBitsToDouble(long)} method, will produce a
886 * floating-point value the same as the argument to
887 * {@code doubleToLongBits} (except all NaN values are
888 * collapsed to a single "canonical" NaN value).
889 *
890 * @param value a {@code double} precision floating-point number.
891 * @return the bits that represent the floating-point number.
892 */
893 @HotSpotIntrinsicCandidate
894 public static long doubleToLongBits(double value) {
895 if (!isNaN(value)) {
896 return doubleToRawLongBits(value);
897 }
898 return 0x7ff8000000000000L;
899 }
900
901 /**
902 * Returns a representation of the specified floating-point value
903 * according to the IEEE 754 floating-point "double
904 * format" bit layout, preserving Not-a-Number (NaN) values.
905 *
906 * <p>Bit 63 (the bit that is selected by the mask
907 * {@code 0x8000000000000000L}) represents the sign of the
908 * floating-point number. Bits
909 * 62-52 (the bits that are selected by the mask
910 * {@code 0x7ff0000000000000L}) represent the exponent. Bits 51-0
911 * (the bits that are selected by the mask
912 * {@code 0x000fffffffffffffL}) represent the significand
913 * (sometimes called the mantissa) of the floating-point number.
914 *
915 * <p>If the argument is positive infinity, the result is
916 * {@code 0x7ff0000000000000L}.
917 *
918 * <p>If the argument is negative infinity, the result is
919 * {@code 0xfff0000000000000L}.
920 *
921 * <p>If the argument is NaN, the result is the {@code long}
922 * integer representing the actual NaN value. Unlike the
923 * {@code doubleToLongBits} method,
924 * {@code doubleToRawLongBits} does not collapse all the bit
925 * patterns encoding a NaN to a single "canonical" NaN
926 * value.
927 *
928 * <p>In all cases, the result is a {@code long} integer that,
929 * when given to the {@link #longBitsToDouble(long)} method, will
930 * produce a floating-point value the same as the argument to
931 * {@code doubleToRawLongBits}.
932 *
933 * @param value a {@code double} precision floating-point number.
934 * @return the bits that represent the floating-point number.
935 * @since 1.3
936 */
937 @HotSpotIntrinsicCandidate
938 public static native long doubleToRawLongBits(double value);
939
940 /**
941 * Returns the {@code double} value corresponding to a given
942 * bit representation.
943 * The argument is considered to be a representation of a
944 * floating-point value according to the IEEE 754 floating-point
945 * "double format" bit layout.
946 *
947 * <p>If the argument is {@code 0x7ff0000000000000L}, the result
948 * is positive infinity.
949 *
950 * <p>If the argument is {@code 0xfff0000000000000L}, the result
951 * is negative infinity.
952 *
953 * <p>If the argument is any value in the range
954 * {@code 0x7ff0000000000001L} through
955 * {@code 0x7fffffffffffffffL} or in the range
956 * {@code 0xfff0000000000001L} through
957 * {@code 0xffffffffffffffffL}, the result is a NaN. No IEEE
958 * 754 floating-point operation provided by Java can distinguish
959 * between two NaN values of the same type with different bit
960 * patterns. Distinct values of NaN are only distinguishable by
961 * use of the {@code Double.doubleToRawLongBits} method.
962 *
963 * <p>In all other cases, let <i>s</i>, <i>e</i>, and <i>m</i> be three
964 * values that can be computed from the argument:
965 *
966 * <blockquote><pre>{@code
967 * int s = ((bits >> 63) == 0) ? 1 : -1;
968 * int e = (int)((bits >> 52) & 0x7ffL);
969 * long m = (e == 0) ?
970 * (bits & 0xfffffffffffffL) << 1 :
971 * (bits & 0xfffffffffffffL) | 0x10000000000000L;
972 * }</pre></blockquote>
973 *
974 * Then the floating-point result equals the value of the mathematical
975 * expression <i>s</i>·<i>m</i>·2<sup><i>e</i>-1075</sup>.
976 *
977 * <p>Note that this method may not be able to return a
978 * {@code double} NaN with exactly same bit pattern as the
979 * {@code long} argument. IEEE 754 distinguishes between two
980 * kinds of NaNs, quiet NaNs and <i>signaling NaNs</i>. The
981 * differences between the two kinds of NaN are generally not
982 * visible in Java. Arithmetic operations on signaling NaNs turn
983 * them into quiet NaNs with a different, but often similar, bit
984 * pattern. However, on some processors merely copying a
985 * signaling NaN also performs that conversion. In particular,
986 * copying a signaling NaN to return it to the calling method
987 * may perform this conversion. So {@code longBitsToDouble}
988 * may not be able to return a {@code double} with a
989 * signaling NaN bit pattern. Consequently, for some
990 * {@code long} values,
991 * {@code doubleToRawLongBits(longBitsToDouble(start))} may
992 * <i>not</i> equal {@code start}. Moreover, which
993 * particular bit patterns represent signaling NaNs is platform
994 * dependent; although all NaN bit patterns, quiet or signaling,
995 * must be in the NaN range identified above.
996 *
997 * @param bits any {@code long} integer.
998 * @return the {@code double} floating-point value with the same
999 * bit pattern.
1000 */
1001 @HotSpotIntrinsicCandidate
1002 public static native double longBitsToDouble(long bits);
1003
1004 /**
1005 * Compares two {@code Double} objects numerically. There
1006 * are two ways in which comparisons performed by this method
1007 * differ from those performed by the Java language numerical
1008 * comparison operators ({@code <, <=, ==, >=, >})
1009 * when applied to primitive {@code double} values:
1010 * <ul><li>
1011 * {@code Double.NaN} is considered by this method
1012 * to be equal to itself and greater than all other
1013 * {@code double} values (including
1014 * {@code Double.POSITIVE_INFINITY}).
1015 * <li>
1016 * {@code 0.0d} is considered by this method to be greater
1017 * than {@code -0.0d}.
1018 * </ul>
1019 * This ensures that the <i>natural ordering</i> of
1020 * {@code Double} objects imposed by this method is <i>consistent
1021 * with equals</i>.
1022 *
1023 * @param anotherDouble the {@code Double} to be compared.
1024 * @return the value {@code 0} if {@code anotherDouble} is
1025 * numerically equal to this {@code Double}; a value
1026 * less than {@code 0} if this {@code Double}
1027 * is numerically less than {@code anotherDouble};
1028 * and a value greater than {@code 0} if this
1029 * {@code Double} is numerically greater than
1030 * {@code anotherDouble}.
1031 *
1032 * @since 1.2
1033 */
1034 public int compareTo(Double anotherDouble) {
1035 return Double.compare(value, anotherDouble.value);
1036 }
1037
1038 /**
1039 * Compares the two specified {@code double} values. The sign
1040 * of the integer value returned is the same as that of the
1041 * integer that would be returned by the call:
1042 * <pre>
1043 * new Double(d1).compareTo(new Double(d2))
1044 * </pre>
1045 *
1046 * @param d1 the first {@code double} to compare
1047 * @param d2 the second {@code double} to compare
1048 * @return the value {@code 0} if {@code d1} is
1049 * numerically equal to {@code d2}; a value less than
1050 * {@code 0} if {@code d1} is numerically less than
1051 * {@code d2}; and a value greater than {@code 0}
1052 * if {@code d1} is numerically greater than
1053 * {@code d2}.
1054 * @since 1.4
1055 */
1056 public static int compare(double d1, double d2) {
1057 if (d1 < d2)
1058 return -1; // Neither val is NaN, thisVal is smaller
1059 if (d1 > d2)
1060 return 1; // Neither val is NaN, thisVal is larger
1061
1062 // Cannot use doubleToRawLongBits because of possibility of NaNs.
1063 long thisBits = Double.doubleToLongBits(d1);
1064 long anotherBits = Double.doubleToLongBits(d2);
1065
1066 return (thisBits == anotherBits ? 0 : // Values are equal
1067 (thisBits < anotherBits ? -1 : // (-0.0, 0.0) or (!NaN, NaN)
1068 1)); // (0.0, -0.0) or (NaN, !NaN)
1069 }
1070
1071 /**
1072 * Adds two {@code double} values together as per the + operator.
1073 *
1074 * @param a the first operand
1075 * @param b the second operand
1076 * @return the sum of {@code a} and {@code b}
1077 * @jls 4.2.4 Floating-Point Operations
1078 * @see java.util.function.BinaryOperator
1079 * @since 1.8
1080 */
1081 public static double sum(double a, double b) {
1082 return a + b;
1083 }
1084
1085 /**
1086 * Returns the greater of two {@code double} values
1087 * as if by calling {@link Math#max(double, double) Math.max}.
1088 *
1089 * @param a the first operand
1090 * @param b the second operand
1091 * @return the greater of {@code a} and {@code b}
1092 * @see java.util.function.BinaryOperator
1093 * @since 1.8
1094 */
1095 public static double max(double a, double b) {
1096 return Math.max(a, b);
1097 }
1098
1099 /**
1100 * Returns the smaller of two {@code double} values
1101 * as if by calling {@link Math#min(double, double) Math.min}.
1102 *
1103 * @param a the first operand
1104 * @param b the second operand
1105 * @return the smaller of {@code a} and {@code b}.
1106 * @see java.util.function.BinaryOperator
1107 * @since 1.8
1108 */
1109 public static double min(double a, double b) {
1110 return Math.min(a, b);
1111 }
1112
1113 /** use serialVersionUID from JDK 1.0.2 for interoperability */
1114 private static final long serialVersionUID = -9172774392245257468L;
1115 }