diff -r cc3871bdd83c -r d382dacfd73f rt/emul/mini/src/main/java/java/lang/Double.java --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/rt/emul/mini/src/main/java/java/lang/Double.java Tue Feb 26 16:54:16 2013 +0100 @@ -0,0 +1,994 @@ +/* + * Copyright (c) 1994, 2010, 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 org.apidesign.bck2brwsr.core.JavaScriptBody; + +/** + * 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}. + * + *

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}. + * + * @author Lee Boynton + * @author Arthur van Hoff + * @author Joseph D. Darcy + * @since JDK1.0 + */ +public final class Double extends Number implements Comparable { + /** + * 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}, + * (2-2-52)·21023. 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}, 2-1022. 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}, 2-1074. 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 {@code Class} instance representing the primitive type + * {@code double}. + * + * @since JDK1.1 + */ + public static final Class TYPE = (Class) Class.getPrimitiveClass("double"); + + /** + * Returns a string representation of the {@code double} + * argument. All characters mentioned below are ASCII characters. + *

+ * How many digits must be printed for the fractional part of + * m or a? 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 + * x is the exact mathematical value represented by the decimal + * representation produced by this method for a finite nonzero argument + * d. Then d must be the {@code double} value nearest + * to x; or if two {@code double} values are equally close + * to x, then d must be one of them and the least + * significant bit of the significand of d must be {@code 0}. + * + *

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. + */ + @JavaScriptBody(args="d", body="var r = d.toString();" + + "if (isFinite(d) && (r.indexOf('.') === -1)) r = r + '.0';" + + "return r;") + public static String toString(double d) { + throw new UnsupportedOperationException(); + } + + /** + * Returns a hexadecimal string representation of the + * {@code double} argument. All characters mentioned below + * are ASCII characters. + * + *

+ * + * + * + * + * + * + * + * + * + * + * + * + * + * + * + * + * + * + *

Examples

Floating-point ValueHexadecimal String
{@code 1.0} {@code 0x1.0p0}
{@code -1.0} {@code -0x1.0p0}
{@code 2.0} {@code 0x1.0p1}
{@code 3.0} {@code 0x1.8p1}
{@code 0.5} {@code 0x1.0p-1}
{@code 0.25} {@code 0x1.0p-2}
{@code Double.MAX_VALUE}{@code 0x1.fffffffffffffp1023}
{@code Minimum Normal Value}{@code 0x1.0p-1022}
{@code Maximum Subnormal Value}{@code 0x0.fffffffffffffp-1022}
{@code Double.MIN_VALUE}{@code 0x0.0000000000001p-1022}
+ * @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) { + throw new UnsupportedOperationException(); +// /* +// * Modeled after the "a" conversion specifier in C99, section +// * 7.19.6.1; however, the output of this method is more +// * tightly specified. +// */ +// if (!FpUtils.isFinite(d) ) +// // For infinity and NaN, use the decimal output. +// return Double.toString(d); +// else { +// // Initialized to maximum size of output. +// StringBuffer answer = new StringBuffer(24); +// +// if (FpUtils.rawCopySign(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 < DoubleConsts.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}$", "")); +// +// // 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("p" + (subnormal ? +// DoubleConsts.MIN_EXPONENT: +// FpUtils.getExponent(d) )); +// } +// return answer.toString(); +// } + } + + /** + * Returns a {@code Double} object holding the + * {@code double} value represented by the argument string + * {@code s}. + * + *

If {@code s} is {@code null}, then a + * {@code NullPointerException} is thrown. + * + *

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 FloatValue as described by the lexical + * syntax rules: + * + *

+ *
+ *
FloatValue: + *
Signopt {@code NaN} + *
Signopt {@code Infinity} + *
Signopt FloatingPointLiteral + *
Signopt HexFloatingPointLiteral + *
SignedInteger + *
+ * + *

+ * + *

+ *
HexFloatingPointLiteral: + *
HexSignificand BinaryExponent FloatTypeSuffixopt + *
+ * + *

+ * + *

+ *
HexSignificand: + *
HexNumeral + *
HexNumeral {@code .} + *
{@code 0x} HexDigitsopt + * {@code .} HexDigits + *
{@code 0X} HexDigitsopt + * {@code .} HexDigits + *
+ * + *

+ * + *

+ *
BinaryExponent: + *
BinaryExponentIndicator SignedInteger + *
+ * + *

+ * + *

+ *
BinaryExponentIndicator: + *
{@code p} + *
{@code P} + *
+ * + *
+ * + * where Sign, FloatingPointLiteral, + * HexNumeral, HexDigits, SignedInteger and + * FloatTypeSuffix are as defined in the lexical structure + * sections of + * The Java™ Language Specification, + * except that underscores are not accepted between digits. + * If {@code s} does not have the form of + * a FloatValue, 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. + * + *

To interpret localized string representations of a + * floating-point value, use subclasses of {@link + * java.text.NumberFormat}. + * + *

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 + * not 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 not + * 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.) + * + *

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: + * + * + * 

+     *  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
+     *  }
+     *
+ * + * + * @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. + */ + @JavaScriptBody(args="s", body="return parseFloat(s);") + public static Double valueOf(String s) throws NumberFormatException { + throw new UnsupportedOperationException(); +// return new Double(FloatingDecimal.readJavaFormatString(s).doubleValue()); + } + + /** + * 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 + */ + 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 + */ + @JavaScriptBody(args="s", body="return parseFloat(s);") + public static double parseDouble(String s) throws NumberFormatException { + throw new UnsupportedOperationException(); +// return FloatingDecimal.readJavaFormatString(s).doubleValue(); + } + + /** + * 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. + */ + static public 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. + */ + static public boolean isInfinite(double v) { + return (v == POSITIVE_INFINITY) || (v == NEGATIVE_INFINITY); + } + + /** + * 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}. + */ + 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. + * @see java.lang.Double#valueOf(java.lang.String) + */ + public Double(String s) throws NumberFormatException { + // REMIND: this is inefficient + this(valueOf(s).doubleValue()); + } + + /** + * 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} (by + * casting to a {@code byte}). + * + * @return the {@code double} value represented by this object + * converted to type {@code byte} + * @since JDK1.1 + */ + public byte byteValue() { + return (byte)value; + } + + /** + * Returns the value of this {@code Double} as a + * {@code short} (by casting to a {@code short}). + * + * @return the {@code double} value represented by this object + * converted to type {@code short} + * @since JDK1.1 + */ + public short shortValue() { + return (short)value; + } + + /** + * Returns the value of this {@code Double} as an + * {@code int} (by casting to type {@code int}). + * + * @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} (by casting to type {@code long}). + * + * @return the {@code double} value represented by this object + * converted to type {@code long} + */ + public long longValue() { + return (long)value; + } + + /** + * Returns the {@code float} value of this + * {@code Double} object. + * + * @return the {@code double} value represented by this object + * converted to type {@code float} + * @since JDK1.0 + */ + 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 + */ + public double doubleValue() { + return (double)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: + * + *
+ * {@code (int)(v^(v>>>32))} + *
+ * + * where {@code v} is defined by: + * + *
+ * {@code long v = Double.doubleToLongBits(this.doubleValue());} + *
+ * + * @return a {@code hash code} value for this object. + */ + public int hashCode() { + 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. + * + *

Note that in most cases, for two instances of class + * {@code Double}, {@code d1} and {@code d2}, the + * value of {@code d1.equals(d2)} is {@code true} if and + * only if + * + *

+ * {@code d1.doubleValue() == d2.doubleValue()} + *
+ * + *

also has the value {@code true}. However, there are two + * exceptions: + *

+ * This definition allows hash tables to operate properly. + * @param obj the object to compare with. + * @return {@code true} if the objects are the same; + * {@code false} otherwise. + * @see java.lang.Double#doubleToLongBits(double) + */ + public boolean equals(Object obj) { + return (obj instanceof Double) + && (((Double)obj).value) == value; + } + + /** + * Returns a representation of the specified floating-point value + * according to the IEEE 754 floating-point "double + * format" bit layout. + * + *

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. + * + *

If the argument is positive infinity, the result is + * {@code 0x7ff0000000000000L}. + * + *

If the argument is negative infinity, the result is + * {@code 0xfff0000000000000L}. + * + *

If the argument is NaN, the result is + * {@code 0x7ff8000000000000L}. + * + *

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. + */ + public static long doubleToLongBits(double value) { + throw new UnsupportedOperationException(); +// long result = doubleToRawLongBits(value); +// // Check for NaN based on values of bit fields, maximum +// // exponent and nonzero significand. +// if ( ((result & DoubleConsts.EXP_BIT_MASK) == +// DoubleConsts.EXP_BIT_MASK) && +// (result & DoubleConsts.SIGNIF_BIT_MASK) != 0L) +// result = 0x7ff8000000000000L; +// return result; + } + + /** + * 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. + * + *

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. + * + *

If the argument is positive infinity, the result is + * {@code 0x7ff0000000000000L}. + * + *

If the argument is negative infinity, the result is + * {@code 0xfff0000000000000L}. + * + *

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. + * + *

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 + */ + 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. + * + *

If the argument is {@code 0x7ff0000000000000L}, the result + * is positive infinity. + * + *

If the argument is {@code 0xfff0000000000000L}, the result + * is negative infinity. + * + *

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. + * + *

In all other cases, let s, e, and m be three + * values that can be computed from the argument: + * + * 

+     * int s = ((bits >> 63) == 0) ? 1 : -1;
+     * int e = (int)((bits >> 52) & 0x7ffL);
+     * long m = (e == 0) ?
+     *                 (bits & 0xfffffffffffffL) << 1 :
+     *                 (bits & 0xfffffffffffffL) | 0x10000000000000L;
+     *
+ * + * Then the floating-point result equals the value of the mathematical + * expression s·m·2e-1075. + * + *

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 signaling NaNs. 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 + * not 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. + */ + public static native double longBitsToDouble(long bits); + + /** + * Compares two {@code Double} objects numerically. There + * are two ways in which comparisons performed by this method + * differ from those performed by the Java language numerical + * comparison operators ({@code <, <=, ==, >=, >}) + * when applied to primitive {@code double} values: + *

+ * This ensures that the natural ordering of + * {@code Double} objects imposed by this method is consistent + * with equals. + * + * @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}. + * + * @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: + * 
+     *    new Double(d1).compareTo(new Double(d2))
+     *
+ * + * @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) + } + + /** use serialVersionUID from JDK 1.0.2 for interoperability */ + private static final long serialVersionUID = -9172774392245257468L; +}