| /* |
| * Copyright (c) 1994, 2021, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. Oracle designates this |
| * particular file as subject to the "Classpath" exception as provided |
| * by Oracle in the LICENSE file that accompanied this code. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| */ |
| |
| package java.lang; |
| |
| import java.lang.invoke.MethodHandles; |
| import java.lang.constant.Constable; |
| import java.lang.constant.ConstantDesc; |
| import java.util.Optional; |
| |
| import jdk.internal.math.FloatingDecimal; |
| import jdk.internal.math.DoubleConsts; |
| import jdk.internal.vm.annotation.IntrinsicCandidate; |
| |
| /** |
| * The {@code Double} class wraps a value of the primitive type |
| * {@code double} in an object. An object of type |
| * {@code Double} contains a single field whose type is |
| * {@code double}. |
| * |
| * <p>In addition, this class provides several methods for converting a |
| * {@code double} to a {@code String} and a |
| * {@code String} to a {@code double}, as well as other |
| * constants and methods useful when dealing with a |
| * {@code double}. |
| * |
| * <!-- Android-removed: paragraph on ValueBased |
| * <p>This is a <a href="{@docRoot}/java.base/java/lang/doc-files/ValueBased.html">value-based</a> |
| * class; programmers should treat instances that are |
| * {@linkplain #equals(Object) equal} as interchangeable and should not |
| * use instances for synchronization, or unpredictable behavior may |
| * occur. For example, in a future release, synchronization may fail. |
| * --> |
| * |
| * <h2><a id=equivalenceRelation>Floating-point Equality, Equivalence, |
| * and Comparison</a></h2> |
| * |
| * IEEE 754 floating-point values include finite nonzero values, |
| * signed zeros ({@code +0.0} and {@code -0.0}), signed infinities |
| * {@linkplain Double#POSITIVE_INFINITY positive infinity} and |
| * {@linkplain Double#NEGATIVE_INFINITY negative infinity}), and |
| * {@linkplain Double#NaN NaN} (not-a-number). |
| * |
| * <p>An <em>equivalence relation</em> on a set of values is a boolean |
| * relation on pairs of values that is reflexive, symmetric, and |
| * transitive. For more discussion of equivalence relations and object |
| * equality, see the {@link Object#equals Object.equals} |
| * specification. An equivalence relation partitions the values it |
| * operates over into sets called <i>equivalence classes</i>. All the |
| * members of the equivalence class are equal to each other under the |
| * relation. An equivalence class may contain only a single member. At |
| * least for some purposes, all the members of an equivalence class |
| * are substitutable for each other. In particular, in a numeric |
| * expression equivalent values can be <em>substituted</em> for one |
| * another without changing the result of the expression, meaning |
| * changing the equivalence class of the result of the expression. |
| * |
| * <p>Notably, the built-in {@code ==} operation on floating-point |
| * values is <em>not</em> an equivalence relation. Despite not |
| * defining an equivalence relation, the semantics of the IEEE 754 |
| * {@code ==} operator were deliberately designed to meet other needs |
| * of numerical computation. There are two exceptions where the |
| * properties of an equivalence relation are not satisfied by {@code |
| * ==} on floating-point values: |
| * |
| * <ul> |
| * |
| * <li>If {@code v1} and {@code v2} are both NaN, then {@code v1 |
| * == v2} has the value {@code false}. Therefore, for two NaN |
| * arguments the <em>reflexive</em> property of an equivalence |
| * relation is <em>not</em> satisfied by the {@code ==} operator. |
| * |
| * <li>If {@code v1} represents {@code +0.0} while {@code v2} |
| * represents {@code -0.0}, or vice versa, then {@code v1 == v2} has |
| * the value {@code true} even though {@code +0.0} and {@code -0.0} |
| * are distinguishable under various floating-point operations. For |
| * example, {@code 1.0/+0.0} evaluates to positive infinity while |
| * {@code 1.0/-0.0} evaluates to <em>negative</em> infinity and |
| * positive infinity and negative infinity are neither equal to each |
| * other nor equivalent to each other. Thus, while a signed zero input |
| * most commonly determines the sign of a zero result, because of |
| * dividing by zero, {@code +0.0} and {@code -0.0} may not be |
| * substituted for each other in general. The sign of a zero input |
| * also has a non-substitutable effect on the result of some math |
| * library methods. |
| * |
| * </ul> |
| * |
| * <p>For ordered comparisons using the built-in comparison operators |
| * ({@code <}, {@code <=}, etc.), NaN values have another anomalous |
| * situation: a NaN is neither less than, nor greater than, nor equal |
| * to any value, including itself. This means the <i>trichotomy of |
| * comparison</i> does <em>not</em> hold. |
| * |
| * <p>To provide the appropriate semantics for {@code equals} and |
| * {@code compareTo} methods, those methods cannot simply be wrappers |
| * around {@code ==} or ordered comparison operations. Instead, {@link |
| * Double#equals equals} defines NaN arguments to be equal to each |
| * other and defines {@code +0.0} to <em>not</em> be equal to {@code |
| * -0.0}, restoring reflexivity. For comparisons, {@link |
| * Double#compareTo compareTo} defines a total order where {@code |
| * -0.0} is less than {@code +0.0} and where a NaN is equal to itself |
| * and considered greater than positive infinity. |
| * |
| * <p>The operational semantics of {@code equals} and {@code |
| * compareTo} are expressed in terms of {@linkplain #doubleToLongBits |
| * bit-wise converting} the floating-point values to integral values. |
| * |
| * <p>The <em>natural ordering</em> implemented by {@link #compareTo |
| * compareTo} is {@linkplain Comparable consistent with equals}. That |
| * is, two objects are reported as equal by {@code equals} if and only |
| * if {@code compareTo} on those objects returns zero. |
| * |
| * <p>The adjusted behaviors defined for {@code equals} and {@code |
| * compareTo} allow instances of wrapper classes to work properly with |
| * conventional data structures. For example, defining NaN |
| * values to be {@code equals} to one another allows NaN to be used as |
| * an element of a {@link java.util.HashSet HashSet} or as the key of |
| * a {@link java.util.HashMap HashMap}. Similarly, defining {@code |
| * compareTo} as a total ordering, including {@code +0.0}, {@code |
| * -0.0}, and NaN, allows instances of wrapper classes to be used as |
| * elements of a {@link java.util.SortedSet SortedSet} or as keys of a |
| * {@link java.util.SortedMap SortedMap}. |
| * |
| * @jls 4.2.3 Floating-Point Types, Formats, and Values |
| * @jls 4.2.4. Floating-Point Operations |
| * @jls 15.21.1 Numerical Equality Operators == and != |
| * @jls 15.20.1 Numerical Comparison Operators {@code <}, {@code <=}, {@code >}, and {@code >=} |
| * |
| * @author Lee Boynton |
| * @author Arthur van Hoff |
| * @author Joseph D. Darcy |
| * @since 1.0 |
| */ |
| @jdk.internal.ValueBased |
| public final class Double extends Number |
| implements Comparable<Double>, Constable, ConstantDesc { |
| /** |
| * A constant holding the positive infinity of type |
| * {@code double}. It is equal to the value returned by |
| * {@code Double.longBitsToDouble(0x7ff0000000000000L)}. |
| */ |
| public static final double POSITIVE_INFINITY = 1.0 / 0.0; |
| |
| /** |
| * A constant holding the negative infinity of type |
| * {@code double}. It is equal to the value returned by |
| * {@code Double.longBitsToDouble(0xfff0000000000000L)}. |
| */ |
| public static final double NEGATIVE_INFINITY = -1.0 / 0.0; |
| |
| /** |
| * A constant holding a Not-a-Number (NaN) value of type |
| * {@code double}. It is equivalent to the value returned by |
| * {@code Double.longBitsToDouble(0x7ff8000000000000L)}. |
| */ |
| public static final double NaN = 0.0d / 0.0; |
| |
| /** |
| * A constant holding the largest positive finite value of type |
| * {@code double}, |
| * (2-2<sup>-52</sup>)·2<sup>1023</sup>. It is equal to |
| * the hexadecimal floating-point literal |
| * {@code 0x1.fffffffffffffP+1023} and also equal to |
| * {@code Double.longBitsToDouble(0x7fefffffffffffffL)}. |
| */ |
| public static final double MAX_VALUE = 0x1.fffffffffffffP+1023; // 1.7976931348623157e+308 |
| |
| /** |
| * A constant holding the smallest positive normal value of type |
| * {@code double}, 2<sup>-1022</sup>. It is equal to the |
| * hexadecimal floating-point literal {@code 0x1.0p-1022} and also |
| * equal to {@code Double.longBitsToDouble(0x0010000000000000L)}. |
| * |
| * @since 1.6 |
| */ |
| public static final double MIN_NORMAL = 0x1.0p-1022; // 2.2250738585072014E-308 |
| |
| /** |
| * A constant holding the smallest positive nonzero value of type |
| * {@code double}, 2<sup>-1074</sup>. It is equal to the |
| * hexadecimal floating-point literal |
| * {@code 0x0.0000000000001P-1022} and also equal to |
| * {@code Double.longBitsToDouble(0x1L)}. |
| */ |
| public static final double MIN_VALUE = 0x0.0000000000001P-1022; // 4.9e-324 |
| |
| /** |
| * Maximum exponent a finite {@code double} variable may have. |
| * It is equal to the value returned by |
| * {@code Math.getExponent(Double.MAX_VALUE)}. |
| * |
| * @since 1.6 |
| */ |
| public static final int MAX_EXPONENT = 1023; |
| |
| /** |
| * Minimum exponent a normalized {@code double} variable may |
| * have. It is equal to the value returned by |
| * {@code Math.getExponent(Double.MIN_NORMAL)}. |
| * |
| * @since 1.6 |
| */ |
| public static final int MIN_EXPONENT = -1022; |
| |
| /** |
| * The number of bits used to represent a {@code double} value. |
| * |
| * @since 1.5 |
| */ |
| public static final int SIZE = 64; |
| |
| /** |
| * The number of bits in the significand of a {@code double} value. |
| * This is the parameter N in section {@jls 4.2.3} of |
| * <cite>The Java Language Specification</cite>. |
| * |
| * @since 19 |
| */ |
| public static final int PRECISION = 53; |
| |
| /** |
| * The number of bytes used to represent a {@code double} value. |
| * |
| * @since 1.8 |
| */ |
| public static final int BYTES = SIZE / Byte.SIZE; |
| |
| /** |
| * The {@code Class} instance representing the primitive type |
| * {@code double}. |
| * |
| * @since 1.1 |
| */ |
| @SuppressWarnings("unchecked") |
| public static final Class<Double> TYPE = (Class<Double>) Class.getPrimitiveClass("double"); |
| |
| /** |
| * Returns a string representation of the {@code double} |
| * argument. All characters mentioned below are ASCII characters. |
| * <ul> |
| * <li>If the argument is NaN, the result is the string |
| * "{@code NaN}". |
| * <li>Otherwise, the result is a string that represents the sign and |
| * magnitude (absolute value) of the argument. If the sign is negative, |
| * the first character of the result is '{@code -}' |
| * ({@code '\u005Cu002D'}); if the sign is positive, no sign character |
| * appears in the result. As for the magnitude <i>m</i>: |
| * <ul> |
| * <li>If <i>m</i> is infinity, it is represented by the characters |
| * {@code "Infinity"}; thus, positive infinity produces the result |
| * {@code "Infinity"} and negative infinity produces the result |
| * {@code "-Infinity"}. |
| * |
| * <li>If <i>m</i> is zero, it is represented by the characters |
| * {@code "0.0"}; thus, negative zero produces the result |
| * {@code "-0.0"} and positive zero produces the result |
| * {@code "0.0"}. |
| * |
| * <li>If <i>m</i> is greater than or equal to 10<sup>-3</sup> but less |
| * than 10<sup>7</sup>, then it is represented as the integer part of |
| * <i>m</i>, in decimal form with no leading zeroes, followed by |
| * '{@code .}' ({@code '\u005Cu002E'}), followed by one or |
| * more decimal digits representing the fractional part of <i>m</i>. |
| * |
| * <li>If <i>m</i> is less than 10<sup>-3</sup> or greater than or |
| * equal to 10<sup>7</sup>, then it is represented in so-called |
| * "computerized scientific notation." Let <i>n</i> be the unique |
| * integer such that 10<sup><i>n</i></sup> ≤ <i>m</i> {@literal <} |
| * 10<sup><i>n</i>+1</sup>; then let <i>a</i> be the |
| * mathematically exact quotient of <i>m</i> and |
| * 10<sup><i>n</i></sup> so that 1 ≤ <i>a</i> {@literal <} 10. The |
| * magnitude is then represented as the integer part of <i>a</i>, |
| * as a single decimal digit, followed by '{@code .}' |
| * ({@code '\u005Cu002E'}), followed by decimal digits |
| * representing the fractional part of <i>a</i>, followed by the |
| * letter '{@code E}' ({@code '\u005Cu0045'}), followed |
| * by a representation of <i>n</i> as a decimal integer, as |
| * produced by the method {@link Integer#toString(int)}. |
| * </ul> |
| * </ul> |
| * How many digits must be printed for the fractional part of |
| * <i>m</i> or <i>a</i>? There must be at least one digit to represent |
| * the fractional part, and beyond that as many, but only as many, more |
| * digits as are needed to uniquely distinguish the argument value from |
| * adjacent values of type {@code double}. That is, suppose that |
| * <i>x</i> is the exact mathematical value represented by the decimal |
| * representation produced by this method for a finite nonzero argument |
| * <i>d</i>. Then <i>d</i> must be the {@code double} value nearest |
| * to <i>x</i>; or if two {@code double} values are equally close |
| * to <i>x</i>, then <i>d</i> must be one of them and the least |
| * significant bit of the significand of <i>d</i> must be {@code 0}. |
| * |
| * <p>To create localized string representations of a floating-point |
| * value, use subclasses of {@link java.text.NumberFormat}. |
| * |
| * @param d the {@code double} to be converted. |
| * @return a string representation of the argument. |
| */ |
| public static String toString(double d) { |
| return FloatingDecimal.toJavaFormatString(d); |
| } |
| |
| /** |
| * Returns a hexadecimal string representation of the |
| * {@code double} argument. All characters mentioned below |
| * are ASCII characters. |
| * |
| * <ul> |
| * <li>If the argument is NaN, the result is the string |
| * "{@code NaN}". |
| * <li>Otherwise, the result is a string that represents the sign |
| * and magnitude of the argument. If the sign is negative, the |
| * first character of the result is '{@code -}' |
| * ({@code '\u005Cu002D'}); if the sign is positive, no sign |
| * character appears in the result. As for the magnitude <i>m</i>: |
| * |
| * <ul> |
| * <li>If <i>m</i> is infinity, it is represented by the string |
| * {@code "Infinity"}; thus, positive infinity produces the |
| * result {@code "Infinity"} and negative infinity produces |
| * the result {@code "-Infinity"}. |
| * |
| * <li>If <i>m</i> is zero, it is represented by the string |
| * {@code "0x0.0p0"}; thus, negative zero produces the result |
| * {@code "-0x0.0p0"} and positive zero produces the result |
| * {@code "0x0.0p0"}. |
| * |
| * <li>If <i>m</i> is a {@code double} value with a |
| * normalized representation, substrings are used to represent the |
| * significand and exponent fields. The significand is |
| * represented by the characters {@code "0x1."} |
| * followed by a lowercase hexadecimal representation of the rest |
| * of the significand as a fraction. Trailing zeros in the |
| * hexadecimal representation are removed unless all the digits |
| * are zero, in which case a single zero is used. Next, the |
| * exponent is represented by {@code "p"} followed |
| * by a decimal string of the unbiased exponent as if produced by |
| * a call to {@link Integer#toString(int) Integer.toString} on the |
| * exponent value. |
| * |
| * <li>If <i>m</i> is a {@code double} value with a subnormal |
| * representation, the significand is represented by the |
| * characters {@code "0x0."} followed by a |
| * hexadecimal representation of the rest of the significand as a |
| * fraction. Trailing zeros in the hexadecimal representation are |
| * removed. Next, the exponent is represented by |
| * {@code "p-1022"}. Note that there must be at |
| * least one nonzero digit in a subnormal significand. |
| * |
| * </ul> |
| * |
| * </ul> |
| * |
| * <table class="striped"> |
| * <caption>Examples</caption> |
| * <thead> |
| * <tr><th scope="col">Floating-point Value</th><th scope="col">Hexadecimal String</th> |
| * </thead> |
| * <tbody style="text-align:right"> |
| * <tr><th scope="row">{@code 1.0}</th> <td>{@code 0x1.0p0}</td> |
| * <tr><th scope="row">{@code -1.0}</th> <td>{@code -0x1.0p0}</td> |
| * <tr><th scope="row">{@code 2.0}</th> <td>{@code 0x1.0p1}</td> |
| * <tr><th scope="row">{@code 3.0}</th> <td>{@code 0x1.8p1}</td> |
| * <tr><th scope="row">{@code 0.5}</th> <td>{@code 0x1.0p-1}</td> |
| * <tr><th scope="row">{@code 0.25}</th> <td>{@code 0x1.0p-2}</td> |
| * <tr><th scope="row">{@code Double.MAX_VALUE}</th> |
| * <td>{@code 0x1.fffffffffffffp1023}</td> |
| * <tr><th scope="row">{@code Minimum Normal Value}</th> |
| * <td>{@code 0x1.0p-1022}</td> |
| * <tr><th scope="row">{@code Maximum Subnormal Value}</th> |
| * <td>{@code 0x0.fffffffffffffp-1022}</td> |
| * <tr><th scope="row">{@code Double.MIN_VALUE}</th> |
| * <td>{@code 0x0.0000000000001p-1022}</td> |
| * </tbody> |
| * </table> |
| * @param d the {@code double} to be converted. |
| * @return a hex string representation of the argument. |
| * @since 1.5 |
| * @author Joseph D. Darcy |
| */ |
| public static String toHexString(double d) { |
| /* |
| * Modeled after the "a" conversion specifier in C99, section |
| * 7.19.6.1; however, the output of this method is more |
| * tightly specified. |
| */ |
| if (!isFinite(d) ) |
| // For infinity and NaN, use the decimal output. |
| return Double.toString(d); |
| else { |
| // Initialized to maximum size of output. |
| StringBuilder answer = new StringBuilder(24); |
| |
| if (Math.copySign(1.0, d) == -1.0) // value is negative, |
| answer.append("-"); // so append sign info |
| |
| answer.append("0x"); |
| |
| d = Math.abs(d); |
| |
| if(d == 0.0) { |
| answer.append("0.0p0"); |
| } else { |
| boolean subnormal = (d < Double.MIN_NORMAL); |
| |
| // Isolate significand bits and OR in a high-order bit |
| // so that the string representation has a known |
| // length. |
| long signifBits = (Double.doubleToLongBits(d) |
| & DoubleConsts.SIGNIF_BIT_MASK) | |
| 0x1000000000000000L; |
| |
| // Subnormal values have a 0 implicit bit; normal |
| // values have a 1 implicit bit. |
| answer.append(subnormal ? "0." : "1."); |
| |
| // Isolate the low-order 13 digits of the hex |
| // representation. If all the digits are zero, |
| // replace with a single 0; otherwise, remove all |
| // trailing zeros. |
| String signif = Long.toHexString(signifBits).substring(3,16); |
| answer.append(signif.equals("0000000000000") ? // 13 zeros |
| "0": |
| signif.replaceFirst("0{1,12}$", "")); |
| |
| answer.append('p'); |
| // If the value is subnormal, use the E_min exponent |
| // value for double; otherwise, extract and report d's |
| // exponent (the representation of a subnormal uses |
| // E_min -1). |
| answer.append(subnormal ? |
| Double.MIN_EXPONENT: |
| Math.getExponent(d)); |
| } |
| return answer.toString(); |
| } |
| } |
| |
| /** |
| * Returns a {@code Double} object holding the |
| * {@code double} value represented by the argument string |
| * {@code s}. |
| * |
| * <p>If {@code s} is {@code null}, then a |
| * {@code NullPointerException} is thrown. |
| * |
| * <p>Leading and trailing whitespace characters in {@code s} |
| * are ignored. Whitespace is removed as if by the {@link |
| * String#trim} method; that is, both ASCII space and control |
| * characters are removed. The rest of {@code s} should |
| * constitute a <i>FloatValue</i> as described by the lexical |
| * syntax rules: |
| * |
| * <blockquote> |
| * <dl> |
| * <dt><i>FloatValue:</i> |
| * <dd><i>Sign<sub>opt</sub></i> {@code NaN} |
| * <dd><i>Sign<sub>opt</sub></i> {@code Infinity} |
| * <dd><i>Sign<sub>opt</sub> FloatingPointLiteral</i> |
| * <dd><i>Sign<sub>opt</sub> HexFloatingPointLiteral</i> |
| * <dd><i>SignedInteger</i> |
| * </dl> |
| * |
| * <dl> |
| * <dt><i>HexFloatingPointLiteral</i>: |
| * <dd> <i>HexSignificand BinaryExponent FloatTypeSuffix<sub>opt</sub></i> |
| * </dl> |
| * |
| * <dl> |
| * <dt><i>HexSignificand:</i> |
| * <dd><i>HexNumeral</i> |
| * <dd><i>HexNumeral</i> {@code .} |
| * <dd>{@code 0x} <i>HexDigits<sub>opt</sub> |
| * </i>{@code .}<i> HexDigits</i> |
| * <dd>{@code 0X}<i> HexDigits<sub>opt</sub> |
| * </i>{@code .} <i>HexDigits</i> |
| * </dl> |
| * |
| * <dl> |
| * <dt><i>BinaryExponent:</i> |
| * <dd><i>BinaryExponentIndicator SignedInteger</i> |
| * </dl> |
| * |
| * <dl> |
| * <dt><i>BinaryExponentIndicator:</i> |
| * <dd>{@code p} |
| * <dd>{@code P} |
| * </dl> |
| * |
| * </blockquote> |
| * |
| * where <i>Sign</i>, <i>FloatingPointLiteral</i>, |
| * <i>HexNumeral</i>, <i>HexDigits</i>, <i>SignedInteger</i> and |
| * <i>FloatTypeSuffix</i> are as defined in the lexical structure |
| * sections of |
| * <cite>The Java Language Specification</cite>, |
| * except that underscores are not accepted between digits. |
| * If {@code s} does not have the form of |
| * a <i>FloatValue</i>, then a {@code NumberFormatException} |
| * is thrown. Otherwise, {@code s} is regarded as |
| * representing an exact decimal value in the usual |
| * "computerized scientific notation" or as an exact |
| * hexadecimal value; this exact numerical value is then |
| * conceptually converted to an "infinitely precise" |
| * binary value that is then rounded to type {@code double} |
| * by the usual round-to-nearest rule of IEEE 754 floating-point |
| * arithmetic, which includes preserving the sign of a zero |
| * value. |
| * |
| * Note that the round-to-nearest rule also implies overflow and |
| * underflow behaviour; if the exact value of {@code s} is large |
| * enough in magnitude (greater than or equal to ({@link |
| * #MAX_VALUE} + {@link Math#ulp(double) ulp(MAX_VALUE)}/2), |
| * rounding to {@code double} will result in an infinity and if the |
| * exact value of {@code s} is small enough in magnitude (less |
| * than or equal to {@link #MIN_VALUE}/2), rounding to float will |
| * result in a zero. |
| * |
| * Finally, after rounding a {@code Double} object representing |
| * this {@code double} value is returned. |
| * |
| * <p> To interpret localized string representations of a |
| * floating-point value, use subclasses of {@link |
| * java.text.NumberFormat}. |
| * |
| * <p>Note that trailing format specifiers, specifiers that |
| * determine the type of a floating-point literal |
| * ({@code 1.0f} is a {@code float} value; |
| * {@code 1.0d} is a {@code double} value), do |
| * <em>not</em> influence the results of this method. In other |
| * words, the numerical value of the input string is converted |
| * directly to the target floating-point type. The two-step |
| * sequence of conversions, string to {@code float} followed |
| * by {@code float} to {@code double}, is <em>not</em> |
| * equivalent to converting a string directly to |
| * {@code double}. For example, the {@code float} |
| * literal {@code 0.1f} is equal to the {@code double} |
| * value {@code 0.10000000149011612}; the {@code float} |
| * literal {@code 0.1f} represents a different numerical |
| * value than the {@code double} literal |
| * {@code 0.1}. (The numerical value 0.1 cannot be exactly |
| * represented in a binary floating-point number.) |
| * |
| * <p>To avoid calling this method on an invalid string and having |
| * a {@code NumberFormatException} be thrown, the regular |
| * expression below can be used to screen the input string: |
| * |
| * <pre>{@code |
| * final String Digits = "(\\p{Digit}+)"; |
| * final String HexDigits = "(\\p{XDigit}+)"; |
| * // an exponent is 'e' or 'E' followed by an optionally |
| * // signed decimal integer. |
| * final String Exp = "[eE][+-]?"+Digits; |
| * final String fpRegex = |
| * ("[\\x00-\\x20]*"+ // Optional leading "whitespace" |
| * "[+-]?(" + // Optional sign character |
| * "NaN|" + // "NaN" string |
| * "Infinity|" + // "Infinity" string |
| * |
| * // A decimal floating-point string representing a finite positive |
| * // number without a leading sign has at most five basic pieces: |
| * // Digits . Digits ExponentPart FloatTypeSuffix |
| * // |
| * // Since this method allows integer-only strings as input |
| * // in addition to strings of floating-point literals, the |
| * // two sub-patterns below are simplifications of the grammar |
| * // productions from section 3.10.2 of |
| * // The Java Language Specification. |
| * |
| * // Digits ._opt Digits_opt ExponentPart_opt FloatTypeSuffix_opt |
| * "((("+Digits+"(\\.)?("+Digits+"?)("+Exp+")?)|"+ |
| * |
| * // . Digits ExponentPart_opt FloatTypeSuffix_opt |
| * "(\\.("+Digits+")("+Exp+")?)|"+ |
| * |
| * // Hexadecimal strings |
| * "((" + |
| * // 0[xX] HexDigits ._opt BinaryExponent FloatTypeSuffix_opt |
| * "(0[xX]" + HexDigits + "(\\.)?)|" + |
| * |
| * // 0[xX] HexDigits_opt . HexDigits BinaryExponent FloatTypeSuffix_opt |
| * "(0[xX]" + HexDigits + "?(\\.)" + HexDigits + ")" + |
| * |
| * ")[pP][+-]?" + Digits + "))" + |
| * "[fFdD]?))" + |
| * "[\\x00-\\x20]*");// Optional trailing "whitespace" |
| * |
| * if (Pattern.matches(fpRegex, myString)) |
| * Double.valueOf(myString); // Will not throw NumberFormatException |
| * else { |
| * // Perform suitable alternative action |
| * } |
| * }</pre> |
| * |
| * @param s the string to be parsed. |
| * @return a {@code Double} object holding the value |
| * represented by the {@code String} argument. |
| * @throws NumberFormatException if the string does not contain a |
| * parsable number. |
| */ |
| public static Double valueOf(String s) throws NumberFormatException { |
| return new Double(parseDouble(s)); |
| } |
| |
| /** |
| * Returns a {@code Double} instance representing the specified |
| * {@code double} value. |
| * If a new {@code Double} instance is not required, this method |
| * should generally be used in preference to the constructor |
| * {@link #Double(double)}, as this method is likely to yield |
| * significantly better space and time performance by caching |
| * frequently requested values. |
| * |
| * @param d a double value. |
| * @return a {@code Double} instance representing {@code d}. |
| * @since 1.5 |
| */ |
| @IntrinsicCandidate |
| public static Double valueOf(double d) { |
| return new Double(d); |
| } |
| |
| /** |
| * Returns a new {@code double} initialized to the value |
| * represented by the specified {@code String}, as performed |
| * by the {@code valueOf} method of class |
| * {@code Double}. |
| * |
| * @param s the string to be parsed. |
| * @return the {@code double} value represented by the string |
| * argument. |
| * @throws NullPointerException if the string is null |
| * @throws NumberFormatException if the string does not contain |
| * a parsable {@code double}. |
| * @see java.lang.Double#valueOf(String) |
| * @since 1.2 |
| */ |
| public static double parseDouble(String s) throws NumberFormatException { |
| return FloatingDecimal.parseDouble(s); |
| } |
| |
| /** |
| * Returns {@code true} if the specified number is a |
| * Not-a-Number (NaN) value, {@code false} otherwise. |
| * |
| * @param v the value to be tested. |
| * @return {@code true} if the value of the argument is NaN; |
| * {@code false} otherwise. |
| */ |
| public static boolean isNaN(double v) { |
| return (v != v); |
| } |
| |
| /** |
| * Returns {@code true} if the specified number is infinitely |
| * large in magnitude, {@code false} otherwise. |
| * |
| * @param v the value to be tested. |
| * @return {@code true} if the value of the argument is positive |
| * infinity or negative infinity; {@code false} otherwise. |
| */ |
| public static boolean isInfinite(double v) { |
| return (v == POSITIVE_INFINITY) || (v == NEGATIVE_INFINITY); |
| } |
| |
| /** |
| * Returns {@code true} if the argument is a finite floating-point |
| * value; returns {@code false} otherwise (for NaN and infinity |
| * arguments). |
| * |
| * @param d the {@code double} value to be tested |
| * @return {@code true} if the argument is a finite |
| * floating-point value, {@code false} otherwise. |
| * @since 1.8 |
| */ |
| public static boolean isFinite(double d) { |
| return Math.abs(d) <= Double.MAX_VALUE; |
| } |
| |
| /** |
| * The value of the Double. |
| * |
| * @serial |
| */ |
| private final double value; |
| |
| /** |
| * Constructs a newly allocated {@code Double} object that |
| * represents the primitive {@code double} argument. |
| * |
| * @param value the value to be represented by the {@code Double}. |
| * |
| * @deprecated |
| * It is rarely appropriate to use this constructor. The static factory |
| * {@link #valueOf(double)} is generally a better choice, as it is |
| * likely to yield significantly better space and time performance. |
| */ |
| // Android-changed: not yet forRemoval on Android. |
| @Deprecated(since="9"/*, forRemoval = true*/) |
| public Double(double value) { |
| this.value = value; |
| } |
| |
| /** |
| * Constructs a newly allocated {@code Double} object that |
| * represents the floating-point value of type {@code double} |
| * represented by the string. The string is converted to a |
| * {@code double} value as if by the {@code valueOf} method. |
| * |
| * @param s a string to be converted to a {@code Double}. |
| * @throws NumberFormatException if the string does not contain a |
| * parsable number. |
| * |
| * @deprecated |
| * It is rarely appropriate to use this constructor. |
| * Use {@link #parseDouble(String)} to convert a string to a |
| * {@code double} primitive, or use {@link #valueOf(String)} |
| * to convert a string to a {@code Double} object. |
| */ |
| // Android-changed: not yet forRemoval on Android. |
| @Deprecated(since="9"/*, forRemoval = true */) |
| public Double(String s) throws NumberFormatException { |
| value = parseDouble(s); |
| } |
| |
| /** |
| * Returns {@code true} if this {@code Double} value is |
| * a Not-a-Number (NaN), {@code false} otherwise. |
| * |
| * @return {@code true} if the value represented by this object is |
| * NaN; {@code false} otherwise. |
| */ |
| public boolean isNaN() { |
| return isNaN(value); |
| } |
| |
| /** |
| * Returns {@code true} if this {@code Double} value is |
| * infinitely large in magnitude, {@code false} otherwise. |
| * |
| * @return {@code true} if the value represented by this object is |
| * positive infinity or negative infinity; |
| * {@code false} otherwise. |
| */ |
| public boolean isInfinite() { |
| return isInfinite(value); |
| } |
| |
| /** |
| * Returns a string representation of this {@code Double} object. |
| * The primitive {@code double} value represented by this |
| * object is converted to a string exactly as if by the method |
| * {@code toString} of one argument. |
| * |
| * @return a {@code String} representation of this object. |
| * @see java.lang.Double#toString(double) |
| */ |
| public String toString() { |
| return toString(value); |
| } |
| |
| /** |
| * Returns the value of this {@code Double} as a {@code byte} |
| * after a narrowing primitive conversion. |
| * |
| * @return the {@code double} value represented by this object |
| * converted to type {@code byte} |
| * @jls 5.1.3 Narrowing Primitive Conversion |
| * @since 1.1 |
| */ |
| public byte byteValue() { |
| return (byte)value; |
| } |
| |
| /** |
| * Returns the value of this {@code Double} as a {@code short} |
| * after a narrowing primitive conversion. |
| * |
| * @return the {@code double} value represented by this object |
| * converted to type {@code short} |
| * @jls 5.1.3 Narrowing Primitive Conversion |
| * @since 1.1 |
| */ |
| public short shortValue() { |
| return (short)value; |
| } |
| |
| /** |
| * Returns the value of this {@code Double} as an {@code int} |
| * after a narrowing primitive conversion. |
| * @jls 5.1.3 Narrowing Primitive Conversion |
| * |
| * @return the {@code double} value represented by this object |
| * converted to type {@code int} |
| */ |
| public int intValue() { |
| return (int)value; |
| } |
| |
| /** |
| * Returns the value of this {@code Double} as a {@code long} |
| * after a narrowing primitive conversion. |
| * |
| * @return the {@code double} value represented by this object |
| * converted to type {@code long} |
| * @jls 5.1.3 Narrowing Primitive Conversion |
| */ |
| public long longValue() { |
| return (long)value; |
| } |
| |
| /** |
| * Returns the value of this {@code Double} as a {@code float} |
| * after a narrowing primitive conversion. |
| * |
| * @return the {@code double} value represented by this object |
| * converted to type {@code float} |
| * @jls 5.1.3 Narrowing Primitive Conversion |
| * @since 1.0 |
| */ |
| public float floatValue() { |
| return (float)value; |
| } |
| |
| /** |
| * Returns the {@code double} value of this {@code Double} object. |
| * |
| * @return the {@code double} value represented by this object |
| */ |
| @IntrinsicCandidate |
| public double doubleValue() { |
| return value; |
| } |
| |
| /** |
| * Returns a hash code for this {@code Double} object. The |
| * result is the exclusive OR of the two halves of the |
| * {@code long} integer bit representation, exactly as |
| * produced by the method {@link #doubleToLongBits(double)}, of |
| * the primitive {@code double} value represented by this |
| * {@code Double} object. That is, the hash code is the value |
| * of the expression: |
| * |
| * <blockquote> |
| * {@code (int)(v^(v>>>32))} |
| * </blockquote> |
| * |
| * where {@code v} is defined by: |
| * |
| * <blockquote> |
| * {@code long v = Double.doubleToLongBits(this.doubleValue());} |
| * </blockquote> |
| * |
| * @return a {@code hash code} value for this object. |
| */ |
| @Override |
| public int hashCode() { |
| return Double.hashCode(value); |
| } |
| |
| /** |
| * Returns a hash code for a {@code double} value; compatible with |
| * {@code Double.hashCode()}. |
| * |
| * @param value the value to hash |
| * @return a hash code value for a {@code double} value. |
| * @since 1.8 |
| */ |
| public static int hashCode(double value) { |
| long bits = doubleToLongBits(value); |
| return (int)(bits ^ (bits >>> 32)); |
| } |
| |
| /** |
| * Compares this object against the specified object. The result |
| * is {@code true} if and only if the argument is not |
| * {@code null} and is a {@code Double} object that |
| * represents a {@code double} that has the same value as the |
| * {@code double} represented by this object. For this |
| * purpose, two {@code double} values are considered to be |
| * the same if and only if the method {@link |
| * #doubleToLongBits(double)} returns the identical |
| * {@code long} value when applied to each. |
| * |
| * @apiNote |
| * This method is defined in terms of {@link |
| * #doubleToLongBits(double)} rather than the {@code ==} operator |
| * on {@code double} values since the {@code ==} operator does |
| * <em>not</em> define an equivalence relation and to satisfy the |
| * {@linkplain Object#equals equals contract} an equivalence |
| * relation must be implemented; see <a |
| * href="#equivalenceRelation">this discussion</a> for details of |
| * floating-point equality and equivalence. |
| * |
| * @see java.lang.Double#doubleToLongBits(double) |
| * @jls 15.21.1 Numerical Equality Operators == and != |
| */ |
| public boolean equals(Object obj) { |
| return (obj instanceof Double) |
| && (doubleToLongBits(((Double)obj).value) == |
| doubleToLongBits(value)); |
| } |
| |
| /** |
| * Returns a representation of the specified floating-point value |
| * according to the IEEE 754 floating-point "double |
| * format" bit layout. |
| * |
| * <p>Bit 63 (the bit that is selected by the mask |
| * {@code 0x8000000000000000L}) represents the sign of the |
| * floating-point number. Bits |
| * 62-52 (the bits that are selected by the mask |
| * {@code 0x7ff0000000000000L}) represent the exponent. Bits 51-0 |
| * (the bits that are selected by the mask |
| * {@code 0x000fffffffffffffL}) represent the significand |
| * (sometimes called the mantissa) of the floating-point number. |
| * |
| * <p>If the argument is positive infinity, the result is |
| * {@code 0x7ff0000000000000L}. |
| * |
| * <p>If the argument is negative infinity, the result is |
| * {@code 0xfff0000000000000L}. |
| * |
| * <p>If the argument is NaN, the result is |
| * {@code 0x7ff8000000000000L}. |
| * |
| * <p>In all cases, the result is a {@code long} integer that, when |
| * given to the {@link #longBitsToDouble(long)} method, will produce a |
| * floating-point value the same as the argument to |
| * {@code doubleToLongBits} (except all NaN values are |
| * collapsed to a single "canonical" NaN value). |
| * |
| * @param value a {@code double} precision floating-point number. |
| * @return the bits that represent the floating-point number. |
| */ |
| @IntrinsicCandidate |
| public static long doubleToLongBits(double value) { |
| if (!isNaN(value)) { |
| return doubleToRawLongBits(value); |
| } |
| return 0x7ff8000000000000L; |
| } |
| |
| /** |
| * Returns a representation of the specified floating-point value |
| * according to the IEEE 754 floating-point "double |
| * format" bit layout, preserving Not-a-Number (NaN) values. |
| * |
| * <p>Bit 63 (the bit that is selected by the mask |
| * {@code 0x8000000000000000L}) represents the sign of the |
| * floating-point number. Bits |
| * 62-52 (the bits that are selected by the mask |
| * {@code 0x7ff0000000000000L}) represent the exponent. Bits 51-0 |
| * (the bits that are selected by the mask |
| * {@code 0x000fffffffffffffL}) represent the significand |
| * (sometimes called the mantissa) of the floating-point number. |
| * |
| * <p>If the argument is positive infinity, the result is |
| * {@code 0x7ff0000000000000L}. |
| * |
| * <p>If the argument is negative infinity, the result is |
| * {@code 0xfff0000000000000L}. |
| * |
| * <p>If the argument is NaN, the result is the {@code long} |
| * integer representing the actual NaN value. Unlike the |
| * {@code doubleToLongBits} method, |
| * {@code doubleToRawLongBits} does not collapse all the bit |
| * patterns encoding a NaN to a single "canonical" NaN |
| * value. |
| * |
| * <p>In all cases, the result is a {@code long} integer that, |
| * when given to the {@link #longBitsToDouble(long)} method, will |
| * produce a floating-point value the same as the argument to |
| * {@code doubleToRawLongBits}. |
| * |
| * @param value a {@code double} precision floating-point number. |
| * @return the bits that represent the floating-point number. |
| * @since 1.3 |
| */ |
| @IntrinsicCandidate |
| public static native long doubleToRawLongBits(double value); |
| |
| /** |
| * Returns the {@code double} value corresponding to a given |
| * bit representation. |
| * The argument is considered to be a representation of a |
| * floating-point value according to the IEEE 754 floating-point |
| * "double format" bit layout. |
| * |
| * <p>If the argument is {@code 0x7ff0000000000000L}, the result |
| * is positive infinity. |
| * |
| * <p>If the argument is {@code 0xfff0000000000000L}, the result |
| * is negative infinity. |
| * |
| * <p>If the argument is any value in the range |
| * {@code 0x7ff0000000000001L} through |
| * {@code 0x7fffffffffffffffL} or in the range |
| * {@code 0xfff0000000000001L} through |
| * {@code 0xffffffffffffffffL}, the result is a NaN. No IEEE |
| * 754 floating-point operation provided by Java can distinguish |
| * between two NaN values of the same type with different bit |
| * patterns. Distinct values of NaN are only distinguishable by |
| * use of the {@code Double.doubleToRawLongBits} method. |
| * |
| * <p>In all other cases, let <i>s</i>, <i>e</i>, and <i>m</i> be three |
| * values that can be computed from the argument: |
| * |
| * <blockquote><pre>{@code |
| * int s = ((bits >> 63) == 0) ? 1 : -1; |
| * int e = (int)((bits >> 52) & 0x7ffL); |
| * long m = (e == 0) ? |
| * (bits & 0xfffffffffffffL) << 1 : |
| * (bits & 0xfffffffffffffL) | 0x10000000000000L; |
| * }</pre></blockquote> |
| * |
| * Then the floating-point result equals the value of the mathematical |
| * expression <i>s</i>·<i>m</i>·2<sup><i>e</i>-1075</sup>. |
| * |
| * <p>Note that this method may not be able to return a |
| * {@code double} NaN with exactly same bit pattern as the |
| * {@code long} argument. IEEE 754 distinguishes between two |
| * kinds of NaNs, quiet NaNs and <i>signaling NaNs</i>. The |
| * differences between the two kinds of NaN are generally not |
| * visible in Java. Arithmetic operations on signaling NaNs turn |
| * them into quiet NaNs with a different, but often similar, bit |
| * pattern. However, on some processors merely copying a |
| * signaling NaN also performs that conversion. In particular, |
| * copying a signaling NaN to return it to the calling method |
| * may perform this conversion. So {@code longBitsToDouble} |
| * may not be able to return a {@code double} with a |
| * signaling NaN bit pattern. Consequently, for some |
| * {@code long} values, |
| * {@code doubleToRawLongBits(longBitsToDouble(start))} may |
| * <i>not</i> equal {@code start}. Moreover, which |
| * particular bit patterns represent signaling NaNs is platform |
| * dependent; although all NaN bit patterns, quiet or signaling, |
| * must be in the NaN range identified above. |
| * |
| * @param bits any {@code long} integer. |
| * @return the {@code double} floating-point value with the same |
| * bit pattern. |
| */ |
| @IntrinsicCandidate |
| public static native double longBitsToDouble(long bits); |
| |
| /** |
| * Compares two {@code Double} objects numerically. |
| * |
| * This method imposes a total order on {@code Double} objects |
| * with two differences compared to the incomplete order defined by |
| * the Java language numerical comparison operators ({@code <, <=, |
| * ==, >=, >}) on {@code double} values. |
| * |
| * <ul><li> A NaN is <em>unordered</em> with respect to other |
| * values and unequal to itself under the comparison |
| * operators. This method chooses to define {@code |
| * Double.NaN} to be equal to itself and greater than all |
| * other {@code double} values (including {@code |
| * Double.POSITIVE_INFINITY}). |
| * |
| * <li> Positive zero and negative zero compare equal |
| * numerically, but are distinct and distinguishable values. |
| * This method chooses to define positive zero ({@code +0.0d}), |
| * to be greater than negative zero ({@code -0.0d}). |
| * </ul> |
| |
| * This ensures that the <i>natural ordering</i> of {@code Double} |
| * objects imposed by this method is <i>consistent with |
| * equals</i>; see <a href="#equivalenceRelation">this |
| * discussion</a> for details of floating-point comparison and |
| * ordering. |
| * |
| * @param anotherDouble the {@code Double} to be compared. |
| * @return the value {@code 0} if {@code anotherDouble} is |
| * numerically equal to this {@code Double}; a value |
| * less than {@code 0} if this {@code Double} |
| * is numerically less than {@code anotherDouble}; |
| * and a value greater than {@code 0} if this |
| * {@code Double} is numerically greater than |
| * {@code anotherDouble}. |
| * |
| * @jls 15.20.1 Numerical Comparison Operators {@code <}, {@code <=}, {@code >}, and {@code >=} |
| * @since 1.2 |
| */ |
| public int compareTo(Double anotherDouble) { |
| return Double.compare(value, anotherDouble.value); |
| } |
| |
| /** |
| * Compares the two specified {@code double} values. The sign |
| * of the integer value returned is the same as that of the |
| * integer that would be returned by the call: |
| * <pre> |
| * new Double(d1).compareTo(new Double(d2)) |
| * </pre> |
| * |
| * @param d1 the first {@code double} to compare |
| * @param d2 the second {@code double} to compare |
| * @return the value {@code 0} if {@code d1} is |
| * numerically equal to {@code d2}; a value less than |
| * {@code 0} if {@code d1} is numerically less than |
| * {@code d2}; and a value greater than {@code 0} |
| * if {@code d1} is numerically greater than |
| * {@code d2}. |
| * @since 1.4 |
| */ |
| public static int compare(double d1, double d2) { |
| if (d1 < d2) |
| return -1; // Neither val is NaN, thisVal is smaller |
| if (d1 > d2) |
| return 1; // Neither val is NaN, thisVal is larger |
| |
| // Cannot use doubleToRawLongBits because of possibility of NaNs. |
| long thisBits = Double.doubleToLongBits(d1); |
| long anotherBits = Double.doubleToLongBits(d2); |
| |
| return (thisBits == anotherBits ? 0 : // Values are equal |
| (thisBits < anotherBits ? -1 : // (-0.0, 0.0) or (!NaN, NaN) |
| 1)); // (0.0, -0.0) or (NaN, !NaN) |
| } |
| |
| /** |
| * Adds two {@code double} values together as per the + operator. |
| * |
| * @param a the first operand |
| * @param b the second operand |
| * @return the sum of {@code a} and {@code b} |
| * @jls 4.2.4 Floating-Point Operations |
| * @see java.util.function.BinaryOperator |
| * @since 1.8 |
| */ |
| public static double sum(double a, double b) { |
| return a + b; |
| } |
| |
| /** |
| * Returns the greater of two {@code double} values |
| * as if by calling {@link Math#max(double, double) Math.max}. |
| * |
| * @param a the first operand |
| * @param b the second operand |
| * @return the greater of {@code a} and {@code b} |
| * @see java.util.function.BinaryOperator |
| * @since 1.8 |
| */ |
| public static double max(double a, double b) { |
| return Math.max(a, b); |
| } |
| |
| /** |
| * Returns the smaller of two {@code double} values |
| * as if by calling {@link Math#min(double, double) Math.min}. |
| * |
| * @param a the first operand |
| * @param b the second operand |
| * @return the smaller of {@code a} and {@code b}. |
| * @see java.util.function.BinaryOperator |
| * @since 1.8 |
| */ |
| public static double min(double a, double b) { |
| return Math.min(a, b); |
| } |
| |
| /** |
| * Returns an {@link Optional} containing the nominal descriptor for this |
| * instance, which is the instance itself. |
| * |
| * @return an {@link Optional} describing the {@linkplain Double} instance |
| * @since 12 |
| * @hide |
| */ |
| @Override |
| public Optional<Double> describeConstable() { |
| return Optional.of(this); |
| } |
| |
| /** |
| * Resolves this instance as a {@link ConstantDesc}, the result of which is |
| * the instance itself. |
| * |
| * @param lookup ignored |
| * @return the {@linkplain Double} instance |
| * @since 12 |
| * @hide |
| */ |
| @Override |
| public Double resolveConstantDesc(MethodHandles.Lookup lookup) { |
| return this; |
| } |
| |
| /** use serialVersionUID from JDK 1.0.2 for interoperability */ |
| @java.io.Serial |
| private static final long serialVersionUID = -9172774392245257468L; |
| } |
