/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package java.lang;
/**
* The wrapper for the primitive type {@code double}.
*
* @see java.lang.Number
* @since 1.0
*/
public final class Double extends Number implements Comparable<Double> {
static final int EXPONENT_BIAS = 1023;
static final int EXPONENT_BITS = 12;
static final int MANTISSA_BITS = 52;
static final int NON_MANTISSA_BITS = 12;
static final long SIGN_MASK = 0x8000000000000000L;
static final long EXPONENT_MASK = 0x7ff0000000000000L;
static final long MANTISSA_MASK = 0x000fffffffffffffL;
private static final long serialVersionUID = -9172774392245257468L;
/**
* The value which the receiver represents.
*/
private final double value;
/**
* Constant for the maximum {@code double} value, (2 - 2<sup>-52</sup>) *
* 2<sup>1023</sup>.
*/
public static final double MAX_VALUE = 1.79769313486231570e+308;
/**
* Constant for the minimum {@code double} value, 2<sup>-1074</sup>.
*/
public static final double MIN_VALUE = 5e-324;
/* 4.94065645841246544e-324 gets rounded to 9.88131e-324 */
/**
* Constant for the Not-a-Number (NaN) value of the {@code double} type.
*/
public static final double NaN = 0.0 / 0.0;
/**
* Constant for the positive infinity value of the {@code double} type.
*/
public static final double POSITIVE_INFINITY = 1.0 / 0.0;
/**
* Constant for the negative infinity value of the {@code double} type.
*/
public static final double NEGATIVE_INFINITY = -1.0 / 0.0;
/**
* Constant for the smallest positive normal value of the {@code double} type.
*
* @since 1.6
*/
public static final double MIN_NORMAL = 2.2250738585072014E-308;
/**
* Maximum base-2 exponent that a finite value of the {@code double} type may have.
* Equal to {@code Math.getExponent(Double.MAX_VALUE)}.
*
* @since 1.6
*/
public static final int MAX_EXPONENT = 1023;
/**
* Minimum base-2 exponent that a normal value of the {@code double} type may have.
* Equal to {@code Math.getExponent(Double.MIN_NORMAL)}.
*
* @since 1.6
*/
public static final int MIN_EXPONENT = -1022;
/**
* The {@link Class} object that represents the primitive type {@code
* double}.
*
* @since 1.1
*/
@SuppressWarnings("unchecked")
public static final Class<Double> TYPE
= (Class<Double>) double[].class.getComponentType();
// Note: Double.TYPE can't be set to "double.class", since *that* is
// defined to be "java.lang.Double.TYPE";
/**
* Constant for the number of bits needed to represent a {@code double} in
* two's complement form.
*
* @since 1.5
*/
public static final int SIZE = 64;
/**
* Constructs a new {@code Double} with the specified primitive double
* value.
*
* @param value
* the primitive double value to store in the new instance.
*/
public Double(double value) {
this.value = value;
}
/**
* Constructs a new {@code Double} from the specified string.
*
* @param string
* the string representation of a double value.
* @throws NumberFormatException
* if {@code string} cannot be parsed as a double value.
* @see #parseDouble(String)
*/
public Double(String string) throws NumberFormatException {
this(parseDouble(string));
}
/**
* Compares this object to the specified double object to determine their
* relative order. There are two special cases:
* <ul>
* <li>{@code Double.NaN} is equal to {@code Double.NaN} and it is greater
* than any other double value, including {@code Double.POSITIVE_INFINITY};</li>
* <li>+0.0d is greater than -0.0d</li>
* </ul>
*
* @param object
* the double object to compare this object to.
* @return a negative value if the value of this double is less than the
* value of {@code object}; 0 if the value of this double and the
* value of {@code object} are equal; a positive value if the value
* of this double is greater than the value of {@code object}.
* @throws NullPointerException
* if {@code object} is {@code null}.
* @see java.lang.Comparable
* @since 1.2
*/
public int compareTo(Double object) {
return compare(value, object.value);
}
@Override
public byte byteValue() {
return (byte) value;
}
/**
* Returns an integer corresponding to the bits of the given
* <a href="http://en.wikipedia.org/wiki/IEEE_754-1985">IEEE 754</a> double precision
* {@code value}. All <em>Not-a-Number (NaN)</em> values are converted to a single NaN
* representation ({@code 0x7ff8000000000000L}) (compare to {@link #doubleToRawLongBits}).
*/
public static long doubleToLongBits(double value) {
if (value != value) {
return 0x7ff8000000000000L; // NaN.
} else {
return doubleToRawLongBits(value);
}
}
/**
* Returns an integer corresponding to the bits of the given
* <a href="http://en.wikipedia.org/wiki/IEEE_754-1985">IEEE 754</a> double precision
* {@code value}. <em>Not-a-Number (NaN)</em> values are preserved (compare
* to {@link #doubleToLongBits}).
*/
public static native long doubleToRawLongBits(double value);
/**
* Gets the primitive value of this double.
*
* @return this object's primitive value.
*/
@Override
public double doubleValue() {
return value;
}
/**
* Tests this double for equality with {@code object}.
* To be equal, {@code object} must be an instance of {@code Double} and
* {@code doubleToLongBits} must give the same value for both objects.
*
* <p>Note that, unlike {@code ==}, {@code -0.0} and {@code +0.0} compare
* unequal, and {@code NaN}s compare equal by this method.
*
* @param object
* the object to compare this double with.
* @return {@code true} if the specified object is equal to this
* {@code Double}; {@code false} otherwise.
*/
@Override
public boolean equals(Object object) {
return (object instanceof Double) &&
(doubleToLongBits(this.value) == doubleToLongBits(((Double) object).value));
}
@Override
public float floatValue() {
return (float) value;
}
@Override
public int hashCode() {
long v = doubleToLongBits(value);
return (int) (v ^ (v >>> 32));
}
@Override
public int intValue() {
return (int) value;
}
/**
* Indicates whether this object represents an infinite value.
*
* @return {@code true} if the value of this double is positive or negative
* infinity; {@code false} otherwise.
*/
public boolean isInfinite() {
return isInfinite(value);
}
/**
* Indicates whether the specified double represents an infinite value.
*
* @param d
* the double to check.
* @return {@code true} if the value of {@code d} is positive or negative
* infinity; {@code false} otherwise.
*/
public static boolean isInfinite(double d) {
return (d == POSITIVE_INFINITY) || (d == NEGATIVE_INFINITY);
}
/**
* Indicates whether this object is a <em>Not-a-Number (NaN)</em> value.
*
* @return {@code true} if this double is <em>Not-a-Number</em>;
* {@code false} if it is a (potentially infinite) double number.
*/
public boolean isNaN() {
return isNaN(value);
}
/**
* Indicates whether the specified double is a <em>Not-a-Number (NaN)</em>
* value.
*
* @param d
* the double value to check.
* @return {@code true} if {@code d} is <em>Not-a-Number</em>;
* {@code false} if it is a (potentially infinite) double number.
*/
public static boolean isNaN(double d) {
return d != d;
}
/**
* Returns the <a href="http://en.wikipedia.org/wiki/IEEE_754-1985">IEEE 754</a>
* double precision float corresponding to the given {@code bits}.
*/
public static native double longBitsToDouble(long bits);
@Override
public long longValue() {
return (long) value;
}
/**
* Parses the specified string as a double value.
*
* @param string
* the string representation of a double value.
* @return the primitive double value represented by {@code string}.
* @throws NumberFormatException
* if {@code string} cannot be parsed as a double value.
*/
public static double parseDouble(String string) throws NumberFormatException {
return StringToReal.parseDouble(string);
}
@Override
public short shortValue() {
return (short) value;
}
@Override
public String toString() {
return Double.toString(value);
}
/**
* Returns a string containing a concise, human-readable description of the
* specified double value.
*
* @param d
* the double to convert to a string.
* @return a printable representation of {@code d}.
*/
public static String toString(double d) {
return RealToString.getInstance().doubleToString(d);
}
/**
* Parses the specified string as a double value.
*
* @param string
* the string representation of a double value.
* @return a {@code Double} instance containing the double value represented
* by {@code string}.
* @throws NumberFormatException
* if {@code string} cannot be parsed as a double value.
* @see #parseDouble(String)
*/
public static Double valueOf(String string) throws NumberFormatException {
return parseDouble(string);
}
/**
* Compares the two specified double values. There are two special cases:
* <ul>
* <li>{@code Double.NaN} is equal to {@code Double.NaN} and it is greater
* than any other double value, including {@code Double.POSITIVE_INFINITY};</li>
* <li>+0.0d is greater than -0.0d</li>
* </ul>
*
* @param double1
* the first value to compare.
* @param double2
* the second value to compare.
* @return a negative value if {@code double1} is less than {@code double2};
* 0 if {@code double1} and {@code double2} are equal; a positive
* value if {@code double1} is greater than {@code double2}.
*/
public static int compare(double double1, double double2) {
// Non-zero, non-NaN checking.
if (double1 > double2) {
return 1;
}
if (double2 > double1) {
return -1;
}
if (double1 == double2 && 0.0d != double1) {
return 0;
}
// NaNs are equal to other NaNs and larger than any other double
if (isNaN(double1)) {
if (isNaN(double2)) {
return 0;
}
return 1;
} else if (isNaN(double2)) {
return -1;
}
// Deal with +0.0 and -0.0
long d1 = doubleToRawLongBits(double1);
long d2 = doubleToRawLongBits(double2);
// The below expression is equivalent to:
// (d1 == d2) ? 0 : (d1 < d2) ? -1 : 1
return (int) ((d1 >> 63) - (d2 >> 63));
}
/**
* Returns a {@code Double} instance for the specified double value.
*
* @param d
* the double value to store in the instance.
* @return a {@code Double} instance containing {@code d}.
* @since 1.5
*/
public static Double valueOf(double d) {
return new Double(d);
}
/**
* Converts the specified double into its hexadecimal string representation.
*
* @param d
* the double to convert.
* @return the hexadecimal string representation of {@code d}.
* @since 1.5
*/
public static String toHexString(double d) {
/*
* Reference: http://en.wikipedia.org/wiki/IEEE_754-1985
*/
if (d != d) {
return "NaN";
}
if (d == POSITIVE_INFINITY) {
return "Infinity";
}
if (d == NEGATIVE_INFINITY) {
return "-Infinity";
}
long bitValue = doubleToLongBits(d);
boolean negative = (bitValue & 0x8000000000000000L) != 0;
// mask exponent bits and shift down
long exponent = (bitValue & 0x7FF0000000000000L) >>> 52;
// mask significand bits and shift up
long significand = bitValue & 0x000FFFFFFFFFFFFFL;
if (exponent == 0 && significand == 0) {
return (negative ? "-0x0.0p0" : "0x0.0p0");
}
StringBuilder hexString = new StringBuilder(10);
if (negative) {
hexString.append("-0x");
} else {
hexString.append("0x");
}
if (exponent == 0) { // denormal (subnormal) value
hexString.append("0.");
// significand is 52-bits, so there can be 13 hex digits
int fractionDigits = 13;
// remove trailing hex zeros, so Integer.toHexString() won't print
// them
while ((significand != 0) && ((significand & 0xF) == 0)) {
significand >>>= 4;
fractionDigits--;
}
// this assumes Integer.toHexString() returns lowercase characters
String hexSignificand = Long.toHexString(significand);
// if there are digits left, then insert some '0' chars first
if (significand != 0 && fractionDigits > hexSignificand.length()) {
int digitDiff = fractionDigits - hexSignificand.length();
while (digitDiff-- != 0) {
hexString.append('0');
}
}
hexString.append(hexSignificand);
hexString.append("p-1022");
} else { // normal value
hexString.append("1.");
// significand is 52-bits, so there can be 13 hex digits
int fractionDigits = 13;
// remove trailing hex zeros, so Integer.toHexString() won't print
// them
while ((significand != 0) && ((significand & 0xF) == 0)) {
significand >>>= 4;
fractionDigits--;
}
// this assumes Integer.toHexString() returns lowercase characters
String hexSignificand = Long.toHexString(significand);
// if there are digits left, then insert some '0' chars first
if (significand != 0 && fractionDigits > hexSignificand.length()) {
int digitDiff = fractionDigits - hexSignificand.length();
while (digitDiff-- != 0) {
hexString.append('0');
}
}
hexString.append(hexSignificand);
hexString.append('p');
// remove exponent's 'bias' and convert to a string
hexString.append(Long.toString(exponent - 1023));
}
return hexString.toString();
}
}