2 * Copyright (c) 1994, 2010, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
29 * The {@code Double} class wraps a value of the primitive type
30 * {@code double} in an object. An object of type
31 * {@code Double} contains a single field whose type is
34 * <p>In addition, this class provides several methods for converting a
35 * {@code double} to a {@code String} and a
36 * {@code String} to a {@code double}, as well as other
37 * constants and methods useful when dealing with a
41 * @author Arthur van Hoff
42 * @author Joseph D. Darcy
45 public final class Double extends Number implements Comparable<Double> {
47 * A constant holding the positive infinity of type
48 * {@code double}. It is equal to the value returned by
49 * {@code Double.longBitsToDouble(0x7ff0000000000000L)}.
51 public static final double POSITIVE_INFINITY = 1.0 / 0.0;
54 * A constant holding the negative infinity of type
55 * {@code double}. It is equal to the value returned by
56 * {@code Double.longBitsToDouble(0xfff0000000000000L)}.
58 public static final double NEGATIVE_INFINITY = -1.0 / 0.0;
61 * A constant holding a Not-a-Number (NaN) value of type
62 * {@code double}. It is equivalent to the value returned by
63 * {@code Double.longBitsToDouble(0x7ff8000000000000L)}.
65 public static final double NaN = 0.0d / 0.0;
68 * A constant holding the largest positive finite value of type
70 * (2-2<sup>-52</sup>)·2<sup>1023</sup>. It is equal to
71 * the hexadecimal floating-point literal
72 * {@code 0x1.fffffffffffffP+1023} and also equal to
73 * {@code Double.longBitsToDouble(0x7fefffffffffffffL)}.
75 public static final double MAX_VALUE = 0x1.fffffffffffffP+1023; // 1.7976931348623157e+308
78 * A constant holding the smallest positive normal value of type
79 * {@code double}, 2<sup>-1022</sup>. It is equal to the
80 * hexadecimal floating-point literal {@code 0x1.0p-1022} and also
81 * equal to {@code Double.longBitsToDouble(0x0010000000000000L)}.
85 public static final double MIN_NORMAL = 0x1.0p-1022; // 2.2250738585072014E-308
88 * A constant holding the smallest positive nonzero value of type
89 * {@code double}, 2<sup>-1074</sup>. It is equal to the
90 * hexadecimal floating-point literal
91 * {@code 0x0.0000000000001P-1022} and also equal to
92 * {@code Double.longBitsToDouble(0x1L)}.
94 public static final double MIN_VALUE = 0x0.0000000000001P-1022; // 4.9e-324
97 * Maximum exponent a finite {@code double} variable may have.
98 * It is equal to the value returned by
99 * {@code Math.getExponent(Double.MAX_VALUE)}.
103 public static final int MAX_EXPONENT = 1023;
106 * Minimum exponent a normalized {@code double} variable may
107 * have. It is equal to the value returned by
108 * {@code Math.getExponent(Double.MIN_NORMAL)}.
112 public static final int MIN_EXPONENT = -1022;
115 * The number of bits used to represent a {@code double} value.
119 public static final int SIZE = 64;
122 * The {@code Class} instance representing the primitive type
127 public static final Class<Double> TYPE = (Class<Double>) Class.getPrimitiveClass("double");
130 * Returns a string representation of the {@code double}
131 * argument. All characters mentioned below are ASCII characters.
133 * <li>If the argument is NaN, the result is the string
135 * <li>Otherwise, the result is a string that represents the sign and
136 * magnitude (absolute value) of the argument. If the sign is negative,
137 * the first character of the result is '{@code -}'
138 * (<code>'\u002D'</code>); if the sign is positive, no sign character
139 * appears in the result. As for the magnitude <i>m</i>:
141 * <li>If <i>m</i> is infinity, it is represented by the characters
142 * {@code "Infinity"}; thus, positive infinity produces the result
143 * {@code "Infinity"} and negative infinity produces the result
144 * {@code "-Infinity"}.
146 * <li>If <i>m</i> is zero, it is represented by the characters
147 * {@code "0.0"}; thus, negative zero produces the result
148 * {@code "-0.0"} and positive zero produces the result
151 * <li>If <i>m</i> is greater than or equal to 10<sup>-3</sup> but less
152 * than 10<sup>7</sup>, then it is represented as the integer part of
153 * <i>m</i>, in decimal form with no leading zeroes, followed by
154 * '{@code .}' (<code>'\u002E'</code>), followed by one or
155 * more decimal digits representing the fractional part of <i>m</i>.
157 * <li>If <i>m</i> is less than 10<sup>-3</sup> or greater than or
158 * equal to 10<sup>7</sup>, then it is represented in so-called
159 * "computerized scientific notation." Let <i>n</i> be the unique
160 * integer such that 10<sup><i>n</i></sup> ≤ <i>m</i> {@literal <}
161 * 10<sup><i>n</i>+1</sup>; then let <i>a</i> be the
162 * mathematically exact quotient of <i>m</i> and
163 * 10<sup><i>n</i></sup> so that 1 ≤ <i>a</i> {@literal <} 10. The
164 * magnitude is then represented as the integer part of <i>a</i>,
165 * as a single decimal digit, followed by '{@code .}'
166 * (<code>'\u002E'</code>), followed by decimal digits
167 * representing the fractional part of <i>a</i>, followed by the
168 * letter '{@code E}' (<code>'\u0045'</code>), followed
169 * by a representation of <i>n</i> as a decimal integer, as
170 * produced by the method {@link Integer#toString(int)}.
173 * How many digits must be printed for the fractional part of
174 * <i>m</i> or <i>a</i>? There must be at least one digit to represent
175 * the fractional part, and beyond that as many, but only as many, more
176 * digits as are needed to uniquely distinguish the argument value from
177 * adjacent values of type {@code double}. That is, suppose that
178 * <i>x</i> is the exact mathematical value represented by the decimal
179 * representation produced by this method for a finite nonzero argument
180 * <i>d</i>. Then <i>d</i> must be the {@code double} value nearest
181 * to <i>x</i>; or if two {@code double} values are equally close
182 * to <i>x</i>, then <i>d</i> must be one of them and the least
183 * significant bit of the significand of <i>d</i> must be {@code 0}.
185 * <p>To create localized string representations of a floating-point
186 * value, use subclasses of {@link java.text.NumberFormat}.
188 * @param d the {@code double} to be converted.
189 * @return a string representation of the argument.
191 public static String toString(double d) {
192 throw new UnsupportedOperationException();
196 * Returns a hexadecimal string representation of the
197 * {@code double} argument. All characters mentioned below
198 * are ASCII characters.
201 * <li>If the argument is NaN, the result is the string
203 * <li>Otherwise, the result is a string that represents the sign
204 * and magnitude of the argument. If the sign is negative, the
205 * first character of the result is '{@code -}'
206 * (<code>'\u002D'</code>); if the sign is positive, no sign
207 * character appears in the result. As for the magnitude <i>m</i>:
210 * <li>If <i>m</i> is infinity, it is represented by the string
211 * {@code "Infinity"}; thus, positive infinity produces the
212 * result {@code "Infinity"} and negative infinity produces
213 * the result {@code "-Infinity"}.
215 * <li>If <i>m</i> is zero, it is represented by the string
216 * {@code "0x0.0p0"}; thus, negative zero produces the result
217 * {@code "-0x0.0p0"} and positive zero produces the result
220 * <li>If <i>m</i> is a {@code double} value with a
221 * normalized representation, substrings are used to represent the
222 * significand and exponent fields. The significand is
223 * represented by the characters {@code "0x1."}
224 * followed by a lowercase hexadecimal representation of the rest
225 * of the significand as a fraction. Trailing zeros in the
226 * hexadecimal representation are removed unless all the digits
227 * are zero, in which case a single zero is used. Next, the
228 * exponent is represented by {@code "p"} followed
229 * by a decimal string of the unbiased exponent as if produced by
230 * a call to {@link Integer#toString(int) Integer.toString} on the
233 * <li>If <i>m</i> is a {@code double} value with a subnormal
234 * representation, the significand is represented by the
235 * characters {@code "0x0."} followed by a
236 * hexadecimal representation of the rest of the significand as a
237 * fraction. Trailing zeros in the hexadecimal representation are
238 * removed. Next, the exponent is represented by
239 * {@code "p-1022"}. Note that there must be at
240 * least one nonzero digit in a subnormal significand.
247 * <caption><h3>Examples</h3></caption>
248 * <tr><th>Floating-point Value</th><th>Hexadecimal String</th>
249 * <tr><td>{@code 1.0}</td> <td>{@code 0x1.0p0}</td>
250 * <tr><td>{@code -1.0}</td> <td>{@code -0x1.0p0}</td>
251 * <tr><td>{@code 2.0}</td> <td>{@code 0x1.0p1}</td>
252 * <tr><td>{@code 3.0}</td> <td>{@code 0x1.8p1}</td>
253 * <tr><td>{@code 0.5}</td> <td>{@code 0x1.0p-1}</td>
254 * <tr><td>{@code 0.25}</td> <td>{@code 0x1.0p-2}</td>
255 * <tr><td>{@code Double.MAX_VALUE}</td>
256 * <td>{@code 0x1.fffffffffffffp1023}</td>
257 * <tr><td>{@code Minimum Normal Value}</td>
258 * <td>{@code 0x1.0p-1022}</td>
259 * <tr><td>{@code Maximum Subnormal Value}</td>
260 * <td>{@code 0x0.fffffffffffffp-1022}</td>
261 * <tr><td>{@code Double.MIN_VALUE}</td>
262 * <td>{@code 0x0.0000000000001p-1022}</td>
264 * @param d the {@code double} to be converted.
265 * @return a hex string representation of the argument.
267 * @author Joseph D. Darcy
269 public static String toHexString(double d) {
270 throw new UnsupportedOperationException();
272 // * Modeled after the "a" conversion specifier in C99, section
273 // * 7.19.6.1; however, the output of this method is more
274 // * tightly specified.
276 // if (!FpUtils.isFinite(d) )
277 // // For infinity and NaN, use the decimal output.
278 // return Double.toString(d);
280 // // Initialized to maximum size of output.
281 // StringBuffer answer = new StringBuffer(24);
283 // if (FpUtils.rawCopySign(1.0, d) == -1.0) // value is negative,
284 // answer.append("-"); // so append sign info
286 // answer.append("0x");
291 // answer.append("0.0p0");
294 // boolean subnormal = (d < DoubleConsts.MIN_NORMAL);
296 // // Isolate significand bits and OR in a high-order bit
297 // // so that the string representation has a known
299 // long signifBits = (Double.doubleToLongBits(d)
300 // & DoubleConsts.SIGNIF_BIT_MASK) |
301 // 0x1000000000000000L;
303 // // Subnormal values have a 0 implicit bit; normal
304 // // values have a 1 implicit bit.
305 // answer.append(subnormal ? "0." : "1.");
307 // // Isolate the low-order 13 digits of the hex
308 // // representation. If all the digits are zero,
309 // // replace with a single 0; otherwise, remove all
310 // // trailing zeros.
311 // String signif = Long.toHexString(signifBits).substring(3,16);
312 // answer.append(signif.equals("0000000000000") ? // 13 zeros
314 // signif.replaceFirst("0{1,12}$", ""));
316 // // If the value is subnormal, use the E_min exponent
317 // // value for double; otherwise, extract and report d's
318 // // exponent (the representation of a subnormal uses
320 // answer.append("p" + (subnormal ?
321 // DoubleConsts.MIN_EXPONENT:
322 // FpUtils.getExponent(d) ));
324 // return answer.toString();
329 * Returns a {@code Double} object holding the
330 * {@code double} value represented by the argument string
333 * <p>If {@code s} is {@code null}, then a
334 * {@code NullPointerException} is thrown.
336 * <p>Leading and trailing whitespace characters in {@code s}
337 * are ignored. Whitespace is removed as if by the {@link
338 * String#trim} method; that is, both ASCII space and control
339 * characters are removed. The rest of {@code s} should
340 * constitute a <i>FloatValue</i> as described by the lexical
345 * <dt><i>FloatValue:</i>
346 * <dd><i>Sign<sub>opt</sub></i> {@code NaN}
347 * <dd><i>Sign<sub>opt</sub></i> {@code Infinity}
348 * <dd><i>Sign<sub>opt</sub> FloatingPointLiteral</i>
349 * <dd><i>Sign<sub>opt</sub> HexFloatingPointLiteral</i>
350 * <dd><i>SignedInteger</i>
356 * <dt><i>HexFloatingPointLiteral</i>:
357 * <dd> <i>HexSignificand BinaryExponent FloatTypeSuffix<sub>opt</sub></i>
363 * <dt><i>HexSignificand:</i>
364 * <dd><i>HexNumeral</i>
365 * <dd><i>HexNumeral</i> {@code .}
366 * <dd>{@code 0x} <i>HexDigits<sub>opt</sub>
367 * </i>{@code .}<i> HexDigits</i>
368 * <dd>{@code 0X}<i> HexDigits<sub>opt</sub>
369 * </i>{@code .} <i>HexDigits</i>
375 * <dt><i>BinaryExponent:</i>
376 * <dd><i>BinaryExponentIndicator SignedInteger</i>
382 * <dt><i>BinaryExponentIndicator:</i>
389 * where <i>Sign</i>, <i>FloatingPointLiteral</i>,
390 * <i>HexNumeral</i>, <i>HexDigits</i>, <i>SignedInteger</i> and
391 * <i>FloatTypeSuffix</i> are as defined in the lexical structure
393 * <cite>The Java™ Language Specification</cite>,
394 * except that underscores are not accepted between digits.
395 * If {@code s} does not have the form of
396 * a <i>FloatValue</i>, then a {@code NumberFormatException}
397 * is thrown. Otherwise, {@code s} is regarded as
398 * representing an exact decimal value in the usual
399 * "computerized scientific notation" or as an exact
400 * hexadecimal value; this exact numerical value is then
401 * conceptually converted to an "infinitely precise"
402 * binary value that is then rounded to type {@code double}
403 * by the usual round-to-nearest rule of IEEE 754 floating-point
404 * arithmetic, which includes preserving the sign of a zero
407 * Note that the round-to-nearest rule also implies overflow and
408 * underflow behaviour; if the exact value of {@code s} is large
409 * enough in magnitude (greater than or equal to ({@link
410 * #MAX_VALUE} + {@link Math#ulp(double) ulp(MAX_VALUE)}/2),
411 * rounding to {@code double} will result in an infinity and if the
412 * exact value of {@code s} is small enough in magnitude (less
413 * than or equal to {@link #MIN_VALUE}/2), rounding to float will
416 * Finally, after rounding a {@code Double} object representing
417 * this {@code double} value is returned.
419 * <p> To interpret localized string representations of a
420 * floating-point value, use subclasses of {@link
421 * java.text.NumberFormat}.
423 * <p>Note that trailing format specifiers, specifiers that
424 * determine the type of a floating-point literal
425 * ({@code 1.0f} is a {@code float} value;
426 * {@code 1.0d} is a {@code double} value), do
427 * <em>not</em> influence the results of this method. In other
428 * words, the numerical value of the input string is converted
429 * directly to the target floating-point type. The two-step
430 * sequence of conversions, string to {@code float} followed
431 * by {@code float} to {@code double}, is <em>not</em>
432 * equivalent to converting a string directly to
433 * {@code double}. For example, the {@code float}
434 * literal {@code 0.1f} is equal to the {@code double}
435 * value {@code 0.10000000149011612}; the {@code float}
436 * literal {@code 0.1f} represents a different numerical
437 * value than the {@code double} literal
438 * {@code 0.1}. (The numerical value 0.1 cannot be exactly
439 * represented in a binary floating-point number.)
441 * <p>To avoid calling this method on an invalid string and having
442 * a {@code NumberFormatException} be thrown, the regular
443 * expression below can be used to screen the input string:
447 * final String Digits = "(\\p{Digit}+)";
448 * final String HexDigits = "(\\p{XDigit}+)";
449 * // an exponent is 'e' or 'E' followed by an optionally
450 * // signed decimal integer.
451 * final String Exp = "[eE][+-]?"+Digits;
452 * final String fpRegex =
453 * ("[\\x00-\\x20]*"+ // Optional leading "whitespace"
454 * "[+-]?(" + // Optional sign character
455 * "NaN|" + // "NaN" string
456 * "Infinity|" + // "Infinity" string
458 * // A decimal floating-point string representing a finite positive
459 * // number without a leading sign has at most five basic pieces:
460 * // Digits . Digits ExponentPart FloatTypeSuffix
462 * // Since this method allows integer-only strings as input
463 * // in addition to strings of floating-point literals, the
464 * // two sub-patterns below are simplifications of the grammar
465 * // productions from section 3.10.2 of
466 * // <cite>The Java™ Language Specification</cite>.
468 * // Digits ._opt Digits_opt ExponentPart_opt FloatTypeSuffix_opt
469 * "((("+Digits+"(\\.)?("+Digits+"?)("+Exp+")?)|"+
471 * // . Digits ExponentPart_opt FloatTypeSuffix_opt
472 * "(\\.("+Digits+")("+Exp+")?)|"+
474 * // Hexadecimal strings
476 * // 0[xX] HexDigits ._opt BinaryExponent FloatTypeSuffix_opt
477 * "(0[xX]" + HexDigits + "(\\.)?)|" +
479 * // 0[xX] HexDigits_opt . HexDigits BinaryExponent FloatTypeSuffix_opt
480 * "(0[xX]" + HexDigits + "?(\\.)" + HexDigits + ")" +
482 * ")[pP][+-]?" + Digits + "))" +
484 * "[\\x00-\\x20]*");// Optional trailing "whitespace"
486 * if (Pattern.matches(fpRegex, myString))
487 * Double.valueOf(myString); // Will not throw NumberFormatException
489 * // Perform suitable alternative action
494 * @param s the string to be parsed.
495 * @return a {@code Double} object holding the value
496 * represented by the {@code String} argument.
497 * @throws NumberFormatException if the string does not contain a
500 public static Double valueOf(String s) throws NumberFormatException {
501 throw new UnsupportedOperationException();
502 // return new Double(FloatingDecimal.readJavaFormatString(s).doubleValue());
506 * Returns a {@code Double} instance representing the specified
507 * {@code double} value.
508 * If a new {@code Double} instance is not required, this method
509 * should generally be used in preference to the constructor
510 * {@link #Double(double)}, as this method is likely to yield
511 * significantly better space and time performance by caching
512 * frequently requested values.
514 * @param d a double value.
515 * @return a {@code Double} instance representing {@code d}.
518 public static Double valueOf(double d) {
519 return new Double(d);
523 * Returns a new {@code double} initialized to the value
524 * represented by the specified {@code String}, as performed
525 * by the {@code valueOf} method of class
528 * @param s the string to be parsed.
529 * @return the {@code double} value represented by the string
531 * @throws NullPointerException if the string is null
532 * @throws NumberFormatException if the string does not contain
533 * a parsable {@code double}.
534 * @see java.lang.Double#valueOf(String)
537 public static double parseDouble(String s) throws NumberFormatException {
538 throw new UnsupportedOperationException();
539 // return FloatingDecimal.readJavaFormatString(s).doubleValue();
543 * Returns {@code true} if the specified number is a
544 * Not-a-Number (NaN) value, {@code false} otherwise.
546 * @param v the value to be tested.
547 * @return {@code true} if the value of the argument is NaN;
548 * {@code false} otherwise.
550 static public boolean isNaN(double v) {
555 * Returns {@code true} if the specified number is infinitely
556 * large in magnitude, {@code false} otherwise.
558 * @param v the value to be tested.
559 * @return {@code true} if the value of the argument is positive
560 * infinity or negative infinity; {@code false} otherwise.
562 static public boolean isInfinite(double v) {
563 return (v == POSITIVE_INFINITY) || (v == NEGATIVE_INFINITY);
567 * The value of the Double.
571 private final double value;
574 * Constructs a newly allocated {@code Double} object that
575 * represents the primitive {@code double} argument.
577 * @param value the value to be represented by the {@code Double}.
579 public Double(double value) {
584 * Constructs a newly allocated {@code Double} object that
585 * represents the floating-point value of type {@code double}
586 * represented by the string. The string is converted to a
587 * {@code double} value as if by the {@code valueOf} method.
589 * @param s a string to be converted to a {@code Double}.
590 * @throws NumberFormatException if the string does not contain a
592 * @see java.lang.Double#valueOf(java.lang.String)
594 public Double(String s) throws NumberFormatException {
595 // REMIND: this is inefficient
596 this(valueOf(s).doubleValue());
600 * Returns {@code true} if this {@code Double} value is
601 * a Not-a-Number (NaN), {@code false} otherwise.
603 * @return {@code true} if the value represented by this object is
604 * NaN; {@code false} otherwise.
606 public boolean isNaN() {
611 * Returns {@code true} if this {@code Double} value is
612 * infinitely large in magnitude, {@code false} otherwise.
614 * @return {@code true} if the value represented by this object is
615 * positive infinity or negative infinity;
616 * {@code false} otherwise.
618 public boolean isInfinite() {
619 return isInfinite(value);
623 * Returns a string representation of this {@code Double} object.
624 * The primitive {@code double} value represented by this
625 * object is converted to a string exactly as if by the method
626 * {@code toString} of one argument.
628 * @return a {@code String} representation of this object.
629 * @see java.lang.Double#toString(double)
631 public String toString() {
632 return toString(value);
636 * Returns the value of this {@code Double} as a {@code byte} (by
637 * casting to a {@code byte}).
639 * @return the {@code double} value represented by this object
640 * converted to type {@code byte}
643 public byte byteValue() {
648 * Returns the value of this {@code Double} as a
649 * {@code short} (by casting to a {@code short}).
651 * @return the {@code double} value represented by this object
652 * converted to type {@code short}
655 public short shortValue() {
660 * Returns the value of this {@code Double} as an
661 * {@code int} (by casting to type {@code int}).
663 * @return the {@code double} value represented by this object
664 * converted to type {@code int}
666 public int intValue() {
671 * Returns the value of this {@code Double} as a
672 * {@code long} (by casting to type {@code long}).
674 * @return the {@code double} value represented by this object
675 * converted to type {@code long}
677 public long longValue() {
682 * Returns the {@code float} value of this
683 * {@code Double} object.
685 * @return the {@code double} value represented by this object
686 * converted to type {@code float}
689 public float floatValue() {
694 * Returns the {@code double} value of this
695 * {@code Double} object.
697 * @return the {@code double} value represented by this object
699 public double doubleValue() {
700 return (double)value;
704 * Returns a hash code for this {@code Double} object. The
705 * result is the exclusive OR of the two halves of the
706 * {@code long} integer bit representation, exactly as
707 * produced by the method {@link #doubleToLongBits(double)}, of
708 * the primitive {@code double} value represented by this
709 * {@code Double} object. That is, the hash code is the value
713 * {@code (int)(v^(v>>>32))}
716 * where {@code v} is defined by:
719 * {@code long v = Double.doubleToLongBits(this.doubleValue());}
722 * @return a {@code hash code} value for this object.
724 public int hashCode() {
725 long bits = doubleToLongBits(value);
726 return (int)(bits ^ (bits >>> 32));
730 * Compares this object against the specified object. The result
731 * is {@code true} if and only if the argument is not
732 * {@code null} and is a {@code Double} object that
733 * represents a {@code double} that has the same value as the
734 * {@code double} represented by this object. For this
735 * purpose, two {@code double} values are considered to be
736 * the same if and only if the method {@link
737 * #doubleToLongBits(double)} returns the identical
738 * {@code long} value when applied to each.
740 * <p>Note that in most cases, for two instances of class
741 * {@code Double}, {@code d1} and {@code d2}, the
742 * value of {@code d1.equals(d2)} is {@code true} if and
746 * {@code d1.doubleValue() == d2.doubleValue()}
749 * <p>also has the value {@code true}. However, there are two
752 * <li>If {@code d1} and {@code d2} both represent
753 * {@code Double.NaN}, then the {@code equals} method
754 * returns {@code true}, even though
755 * {@code Double.NaN==Double.NaN} has the value
757 * <li>If {@code d1} represents {@code +0.0} while
758 * {@code d2} represents {@code -0.0}, or vice versa,
759 * the {@code equal} test has the value {@code false},
760 * even though {@code +0.0==-0.0} has the value {@code true}.
762 * This definition allows hash tables to operate properly.
763 * @param obj the object to compare with.
764 * @return {@code true} if the objects are the same;
765 * {@code false} otherwise.
766 * @see java.lang.Double#doubleToLongBits(double)
768 public boolean equals(Object obj) {
769 return (obj instanceof Double)
770 && (doubleToLongBits(((Double)obj).value) ==
771 doubleToLongBits(value));
775 * Returns a representation of the specified floating-point value
776 * according to the IEEE 754 floating-point "double
777 * format" bit layout.
779 * <p>Bit 63 (the bit that is selected by the mask
780 * {@code 0x8000000000000000L}) represents the sign of the
781 * floating-point number. Bits
782 * 62-52 (the bits that are selected by the mask
783 * {@code 0x7ff0000000000000L}) represent the exponent. Bits 51-0
784 * (the bits that are selected by the mask
785 * {@code 0x000fffffffffffffL}) represent the significand
786 * (sometimes called the mantissa) of the floating-point number.
788 * <p>If the argument is positive infinity, the result is
789 * {@code 0x7ff0000000000000L}.
791 * <p>If the argument is negative infinity, the result is
792 * {@code 0xfff0000000000000L}.
794 * <p>If the argument is NaN, the result is
795 * {@code 0x7ff8000000000000L}.
797 * <p>In all cases, the result is a {@code long} integer that, when
798 * given to the {@link #longBitsToDouble(long)} method, will produce a
799 * floating-point value the same as the argument to
800 * {@code doubleToLongBits} (except all NaN values are
801 * collapsed to a single "canonical" NaN value).
803 * @param value a {@code double} precision floating-point number.
804 * @return the bits that represent the floating-point number.
806 public static long doubleToLongBits(double value) {
807 throw new UnsupportedOperationException();
808 // long result = doubleToRawLongBits(value);
809 // // Check for NaN based on values of bit fields, maximum
810 // // exponent and nonzero significand.
811 // if ( ((result & DoubleConsts.EXP_BIT_MASK) ==
812 // DoubleConsts.EXP_BIT_MASK) &&
813 // (result & DoubleConsts.SIGNIF_BIT_MASK) != 0L)
814 // result = 0x7ff8000000000000L;
819 * Returns a representation of the specified floating-point value
820 * according to the IEEE 754 floating-point "double
821 * format" bit layout, preserving Not-a-Number (NaN) values.
823 * <p>Bit 63 (the bit that is selected by the mask
824 * {@code 0x8000000000000000L}) represents the sign of the
825 * floating-point number. Bits
826 * 62-52 (the bits that are selected by the mask
827 * {@code 0x7ff0000000000000L}) represent the exponent. Bits 51-0
828 * (the bits that are selected by the mask
829 * {@code 0x000fffffffffffffL}) represent the significand
830 * (sometimes called the mantissa) of the floating-point number.
832 * <p>If the argument is positive infinity, the result is
833 * {@code 0x7ff0000000000000L}.
835 * <p>If the argument is negative infinity, the result is
836 * {@code 0xfff0000000000000L}.
838 * <p>If the argument is NaN, the result is the {@code long}
839 * integer representing the actual NaN value. Unlike the
840 * {@code doubleToLongBits} method,
841 * {@code doubleToRawLongBits} does not collapse all the bit
842 * patterns encoding a NaN to a single "canonical" NaN
845 * <p>In all cases, the result is a {@code long} integer that,
846 * when given to the {@link #longBitsToDouble(long)} method, will
847 * produce a floating-point value the same as the argument to
848 * {@code doubleToRawLongBits}.
850 * @param value a {@code double} precision floating-point number.
851 * @return the bits that represent the floating-point number.
854 public static native long doubleToRawLongBits(double value);
857 * Returns the {@code double} value corresponding to a given
858 * bit representation.
859 * The argument is considered to be a representation of a
860 * floating-point value according to the IEEE 754 floating-point
861 * "double format" bit layout.
863 * <p>If the argument is {@code 0x7ff0000000000000L}, the result
864 * is positive infinity.
866 * <p>If the argument is {@code 0xfff0000000000000L}, the result
867 * is negative infinity.
869 * <p>If the argument is any value in the range
870 * {@code 0x7ff0000000000001L} through
871 * {@code 0x7fffffffffffffffL} or in the range
872 * {@code 0xfff0000000000001L} through
873 * {@code 0xffffffffffffffffL}, the result is a NaN. No IEEE
874 * 754 floating-point operation provided by Java can distinguish
875 * between two NaN values of the same type with different bit
876 * patterns. Distinct values of NaN are only distinguishable by
877 * use of the {@code Double.doubleToRawLongBits} method.
879 * <p>In all other cases, let <i>s</i>, <i>e</i>, and <i>m</i> be three
880 * values that can be computed from the argument:
883 * int s = ((bits >> 63) == 0) ? 1 : -1;
884 * int e = (int)((bits >> 52) & 0x7ffL);
885 * long m = (e == 0) ?
886 * (bits & 0xfffffffffffffL) << 1 :
887 * (bits & 0xfffffffffffffL) | 0x10000000000000L;
888 * </pre></blockquote>
890 * Then the floating-point result equals the value of the mathematical
891 * expression <i>s</i>·<i>m</i>·2<sup><i>e</i>-1075</sup>.
893 * <p>Note that this method may not be able to return a
894 * {@code double} NaN with exactly same bit pattern as the
895 * {@code long} argument. IEEE 754 distinguishes between two
896 * kinds of NaNs, quiet NaNs and <i>signaling NaNs</i>. The
897 * differences between the two kinds of NaN are generally not
898 * visible in Java. Arithmetic operations on signaling NaNs turn
899 * them into quiet NaNs with a different, but often similar, bit
900 * pattern. However, on some processors merely copying a
901 * signaling NaN also performs that conversion. In particular,
902 * copying a signaling NaN to return it to the calling method
903 * may perform this conversion. So {@code longBitsToDouble}
904 * may not be able to return a {@code double} with a
905 * signaling NaN bit pattern. Consequently, for some
906 * {@code long} values,
907 * {@code doubleToRawLongBits(longBitsToDouble(start))} may
908 * <i>not</i> equal {@code start}. Moreover, which
909 * particular bit patterns represent signaling NaNs is platform
910 * dependent; although all NaN bit patterns, quiet or signaling,
911 * must be in the NaN range identified above.
913 * @param bits any {@code long} integer.
914 * @return the {@code double} floating-point value with the same
917 public static native double longBitsToDouble(long bits);
920 * Compares two {@code Double} objects numerically. There
921 * are two ways in which comparisons performed by this method
922 * differ from those performed by the Java language numerical
923 * comparison operators ({@code <, <=, ==, >=, >})
924 * when applied to primitive {@code double} values:
926 * {@code Double.NaN} is considered by this method
927 * to be equal to itself and greater than all other
928 * {@code double} values (including
929 * {@code Double.POSITIVE_INFINITY}).
931 * {@code 0.0d} is considered by this method to be greater
932 * than {@code -0.0d}.
934 * This ensures that the <i>natural ordering</i> of
935 * {@code Double} objects imposed by this method is <i>consistent
938 * @param anotherDouble the {@code Double} to be compared.
939 * @return the value {@code 0} if {@code anotherDouble} is
940 * numerically equal to this {@code Double}; a value
941 * less than {@code 0} if this {@code Double}
942 * is numerically less than {@code anotherDouble};
943 * and a value greater than {@code 0} if this
944 * {@code Double} is numerically greater than
945 * {@code anotherDouble}.
949 public int compareTo(Double anotherDouble) {
950 return Double.compare(value, anotherDouble.value);
954 * Compares the two specified {@code double} values. The sign
955 * of the integer value returned is the same as that of the
956 * integer that would be returned by the call:
958 * new Double(d1).compareTo(new Double(d2))
961 * @param d1 the first {@code double} to compare
962 * @param d2 the second {@code double} to compare
963 * @return the value {@code 0} if {@code d1} is
964 * numerically equal to {@code d2}; a value less than
965 * {@code 0} if {@code d1} is numerically less than
966 * {@code d2}; and a value greater than {@code 0}
967 * if {@code d1} is numerically greater than
971 public static int compare(double d1, double d2) {
973 return -1; // Neither val is NaN, thisVal is smaller
975 return 1; // Neither val is NaN, thisVal is larger
977 // Cannot use doubleToRawLongBits because of possibility of NaNs.
978 long thisBits = Double.doubleToLongBits(d1);
979 long anotherBits = Double.doubleToLongBits(d2);
981 return (thisBits == anotherBits ? 0 : // Values are equal
982 (thisBits < anotherBits ? -1 : // (-0.0, 0.0) or (!NaN, NaN)
983 1)); // (0.0, -0.0) or (NaN, !NaN)
986 /** use serialVersionUID from JDK 1.0.2 for interoperability */
987 private static final long serialVersionUID = -9172774392245257468L;