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f0fdd66ba4
* java/lang/Double.java: More Classpath merging (isInfinite): Don't use doubleToLongBits (isNaN (Object)): return v != v (initIDs): make native * java/lang/Float.java: Ditto (isInfinite): Don't use floatToIntBits (isNaN (Object)): return v != v * java/lang/natDouble.cc: add empty initIDs() From-SVN: r46370
516 lines
17 KiB
Java
516 lines
17 KiB
Java
/* Double.java -- object wrapper for double primitive
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Copyright (C) 1998, 1999, 2000, 2001 Free Software Foundation, Inc.
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This file is part of GNU Classpath.
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GNU Classpath is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2, or (at your option)
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any later version.
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GNU Classpath is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with GNU Classpath; see the file COPYING. If not, write to the
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Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
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02111-1307 USA.
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As a special exception, if you link this library with other files to
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produce an executable, this library does not by itself cause the
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resulting executable to be covered by the GNU General Public License.
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This exception does not however invalidate any other reasons why the
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executable file might be covered by the GNU General Public License. */
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package java.lang;
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import gnu.classpath.Configuration;
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/* Written using "Java Class Libraries", 2nd edition, ISBN 0-201-31002-3
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* "The Java Language Specification", ISBN 0-201-63451-1
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* plus online API docs for JDK 1.2 beta from http://www.javasoft.com.
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* Status: Believed complete and correct.
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*/
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/**
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* Instances of class <code>Double</code> represent primitive
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* <code>double</code> values.
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*
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* Additionally, this class provides various helper functions and variables
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* related to doubles.
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*
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* @author Paul Fisher
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* @author Andrew Haley <aph@cygnus.com>
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* @since JDK 1.0
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*/
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public final class Double extends Number implements Comparable
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{
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/**
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* The minimum positive value a <code>double</code> may represent
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* is 5e-324.
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*/
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public static final double MIN_VALUE = 5e-324;
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/**
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* The maximum positive value a <code>double</code> may represent
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* is 1.7976931348623157e+308.
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*/
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public static final double MAX_VALUE = 1.7976931348623157e+308;
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/**
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* The value of a double representation -1.0/0.0, negative
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* infinity.
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*/
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public static final double NEGATIVE_INFINITY = -1.0d/0.0d;
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/**
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* The value of a double representing 1.0/0.0, positive infinity.
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*/
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public static final double POSITIVE_INFINITY = 1.0d/0.0d;
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/**
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* All IEEE 754 values of NaN have the same value in Java.
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*/
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public static final double NaN = 0.0d/0.0d;
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/**
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* The primitive type <code>double</code> is represented by this
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* <code>Class</code> object.
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*/
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public static final Class TYPE = VMClassLoader.getPrimitiveClass ("double");
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/**
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* The immutable value of this Double.
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*/
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private final double value;
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private static final long serialVersionUID = -9172774392245257468L;
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/**
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* Load native routines necessary for this class.
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*/
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static
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{
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if (Configuration.INIT_LOAD_LIBRARY)
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{
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System.loadLibrary ("javalang");
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initIDs ();
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}
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}
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/**
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* Create a <code>Double</code> from the primitive <code>double</code>
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* specified.
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*
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* @param value the <code>double</code> argument
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*/
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public Double (double value)
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{
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this.value = value;
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}
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/**
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* Create a <code>Double</code> from the specified
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* <code>String</code>.
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*
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* This method calls <code>Double.parseDouble()</code>.
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*
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* @exception NumberFormatException when the <code>String</code> cannot
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* be parsed into a <code>Float</code>.
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* @param s the <code>String</code> to convert
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* @see #parseDouble(java.lang.String)
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*/
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public Double (String s) throws NumberFormatException
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{
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value = parseDouble (s);
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}
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/**
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* Convert the <code>double</code> value of this <code>Double</code>
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* to a <code>String</code>. This method calls
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* <code>Double.toString(double)</code> to do its dirty work.
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*
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* @return the <code>String</code> representation of this <code>Double</code>.
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* @see #toString(double)
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*/
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public String toString ()
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{
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return toString (value);
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}
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/**
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* If the <code>Object</code> is not <code>null</code>, is an
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* <code>instanceof</code> <code>Double</code>, and represents
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* the same primitive <code>double</code> value return
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* <code>true</code>. Otherwise <code>false</code> is returned.
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* <p>
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* Note that there are two differences between <code>==</code> and
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* <code>equals()</code>. <code>0.0d == -0.0d</code> returns <code>true</code>
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* but <code>new Double(0.0d).equals(new Double(-0.0d))</code> returns
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* <code>false</code>. And <code>Double.NaN == Double.NaN</code> returns
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* <code>false</code>, but
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* <code>new Double(Double.NaN).equals(new Double(Double.NaN))</code> returns
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* <code>true</code>.
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*
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* @param obj the object to compare to
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* @return whether the objects are semantically equal.
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*/
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public boolean equals (Object obj)
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{
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if (!(obj instanceof Double))
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return false;
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Double d = (Double) obj;
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return doubleToLongBits (value) == doubleToLongBits (d.doubleValue ());
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}
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/**
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* The hashcode is the value of the expression: <br>
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* <br>
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* <code>(int)(v^(v>>>32))</code><br>
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* <br>
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* where v is defined by: <br>
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* <code>long v = Double.doubleToLongBits(this.longValue());</code><br>
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*/
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public int hashCode ()
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{
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long v = doubleToLongBits (value);
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return (int) (v ^ (v >>> 32));
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}
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/**
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* Return the value of this <code>Double</code> when cast to an
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* <code>int</code>.
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*/
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public int intValue ()
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{
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return (int) value;
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}
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/**
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* Return the value of this <code>Double</code> when cast to a
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* <code>long</code>.
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*/
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public long longValue ()
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{
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return (long) value;
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}
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/**
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* Return the value of this <code>Double</code> when cast to a
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* <code>float</code>.
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*/
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public float floatValue ()
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{
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return (float) value;
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}
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/**
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* Return the primitive <code>double</code> value represented by this
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* <code>Double</code>.
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*/
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public double doubleValue ()
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{
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return value;
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}
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/**
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* Return the result of calling <code>new Double(java.lang.String)</code>.
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*
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* @param s the <code>String</code> to convert to a <code>Double</code>.
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* @return a new <code>Double</code> representing the <code>String</code>'s
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* numeric value.
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*
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* @exception NullPointerException thrown if <code>String</code> is
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* <code>null</code>.
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* @exception NumberFormatException thrown if <code>String</code> cannot
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* be parsed as a <code>double</code>.
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* @see #Double(java.lang.String)
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* @see #parseDouble(java.lang.String)
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*/
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public static Double valueOf (String s) throws NumberFormatException
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{
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return new Double (s);
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}
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/**
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* Return <code>true</code> if the value of this <code>Double</code>
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* is the same as <code>NaN</code>, otherwise return <code>false</code>.
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* @return whether this <code>Double</code> is <code>NaN</code>.
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*/
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public boolean isNaN ()
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{
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return isNaN (value);
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}
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/**
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* Return <code>true</code> if the <code>double</code> has the same
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* value as <code>NaN</code>, otherwise return <code>false</code>.
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*
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* @param v the <code>double</code> to compare
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* @return whether the argument is <code>NaN</code>.
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*/
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public static boolean isNaN (double v)
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{
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// This works since NaN != NaN is the only reflexive inequality
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// comparison which returns true.
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return v != v;
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}
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/**
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* Return <code>true</code> if the value of this <code>Double</code>
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* is the same as <code>NEGATIVE_INFINITY</code> or
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* <code>POSITIVE_INFINITY</code>, otherwise return <code>false</code>.
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*
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* @return whether this <code>Double</code> is (-/+) infinity.
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*/
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public boolean isInfinite ()
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{
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return isInfinite (value);
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}
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/**
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* Return <code>true</code> if the <code>double</code> has a value
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* equal to either <code>NEGATIVE_INFINITY</code> or
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* <code>POSITIVE_INFINITY</code>, otherwise return <code>false</code>.
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*
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* @param v the <code>double</code> to compare
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* @return whether the argument is (-/+) infinity.
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*/
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public static boolean isInfinite (double v)
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{
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return (v == POSITIVE_INFINITY || v == NEGATIVE_INFINITY);
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}
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/**
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* Returns 0 if the <code>double</code> value of the argument is
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* equal to the value of this <code>Double</code>. Returns a number
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* less than zero if the value of this <code>Double</code> is less
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* than the <code>double</code> value of the argument, and returns a
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* number greater than zero if the value of this <code>Double</code>
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* is greater than the <code>double</code> value of the argument.
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* <br>
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* <code>Double.NaN</code> is greater than any number other than itself,
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* even <code>Double.POSITIVE_INFINITY</code>.
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* <br>
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* <code>0.0d</code> is greater than <code>-0.0d</code>.
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*
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* @param d the Double to compare to.
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* @return 0 if the <code>Double</code>s are the same, < 0 if this
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* <code>Double</code> is less than the <code>Double</code> in
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* in question, or > 0 if it is greater.
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* @since 1.2
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*/
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public int compareTo (Double d)
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{
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return compare (value, d.value);
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}
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/**
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* Returns 0 if the first argument is equal to the second argument.
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* Returns a number less than zero if the first argument is less than the
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* second argument, and returns a number greater than zero if the first
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* argument is greater than the second argument.
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* <br>
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* <code>Double.NaN</code> is greater than any number other than itself,
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* even <code>Double.POSITIVE_INFINITY</code>.
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* <br>
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* <code>0.0d</code> is greater than <code>-0.0d</code>.
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*
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* @param x the first double to compare.
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* @param y the second double to compare.
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* @return 0 if the arguments are the same, < 0 if the
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* first argument is less than the second argument in
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* in question, or > 0 if it is greater.
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* @since 1.4
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*/
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public static int compare (double x, double y)
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{
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if (isNaN (x))
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return isNaN (y) ? 0 : 1;
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if (isNaN (y))
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return -1;
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if (x == 0.0d && y == -0.0d)
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return 1;
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if (x == -0.0d && y == 0.0d)
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return -1;
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if (x == y)
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return 0;
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return x > y ? 1 : -1;
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}
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/**
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* Compares the specified <code>Object</code> to this <code>Double</code>
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* if and only if the <code>Object</code> is an instanceof
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* <code>Double</code>.
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*
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* @param o the Object to compare to.
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* @return 0 if the <code>Double</code>s are the same, < 0 if this
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* <code>Double</code> is less than the <code>Double</code> in
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* in question, or > 0 if it is greater.
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* @throws ClassCastException if the argument is not a <code>Double</code>
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*/
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public int compareTo (Object o)
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{
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return compareTo ((Double) o);
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}
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/**
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* Convert the <code>double</code> to a <code>String</code>.
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* <P>
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*
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* Floating-point string representation is fairly complex: here is a
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* rundown of the possible values. "<CODE>[-]</CODE>" indicates that a
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* negative sign will be printed if the value (or exponent) is negative.
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* "<CODE><number></CODE>" means a string of digits (0-9).
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* "<CODE><digit></CODE>" means a single digit (0-9).
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* <P>
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*
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* <TABLE BORDER=1>
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* <TR><TH>Value of Float</TH><TH>String Representation</TH></TR>
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* <TR>
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* <TD>[+-] 0</TD>
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* <TD>[<CODE>-</CODE>]<CODE>0.0</CODE></TD>
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* </TR>
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* <TR>
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* <TD>Between [+-] 10<SUP>-3</SUP> and 10<SUP>7</SUP></TD>
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* <TD><CODE>[-]number.number</CODE></TD>
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* </TR>
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* <TR>
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* <TD>Other numeric value</TD>
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* <TD><CODE>[-]<digit>.<number>E[-]<number></CODE></TD>
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* </TR>
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* <TR>
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* <TD>[+-] infinity</TD>
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* <TD><CODE>[-]Infinity</CODE></TD>
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* </TR>
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* <TR>
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* <TD>NaN</TD>
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* <TD><CODE>NaN</CODE></TD>
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* </TR>
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* </TABLE>
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*
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* Yes, negative zero <EM>is</EM> a possible value. Note that there is
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* <EM>always</EM> a <CODE>.</CODE> and at least one digit printed after
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* it: even if the number is 3, it will be printed as <CODE>3.0</CODE>.
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* After the ".", all digits will be printed except trailing zeros. No
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* truncation or rounding is done by this function.
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*
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*
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* @XXX specify where we are not in accord with the spec.
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*
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* @param d the <code>double</code> to convert
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* @return the <code>String</code> representing the <code>double</code>.
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*/
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public static String toString (double d)
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{
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return toString (d, false);
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}
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static native String toString (double d, boolean isFloat);
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/**
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* Return the long bits of the specified <code>double</code>.
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* The result of this function can be used as the argument to
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* <code>Double.longBitsToDouble(long)</code> to obtain the
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* original <code>double</code> value.
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*
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* @param value the <code>double</code> to convert
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* @return the bits of the <code>double</code>.
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*/
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public static native long doubleToLongBits (double value);
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/**
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* Return the long bits of the specified <code>double</code>.
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* The result of this function can be used as the argument to
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* <code>Double.longBitsToDouble(long)</code> to obtain the
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* original <code>double</code> value. This method differs from
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* <code>doubleToLongBits</code> in that it does not collapse
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* NaN values.
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*
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* @param value the <code>double</code> to convert
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* @return the bits of the <code>double</code>.
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*/
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public static native long doubleToRawLongBits (double value);
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/**
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* Return the <code>double</code> represented by the long
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* bits specified.
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*
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* @param bits the long bits representing a <code>double</code>
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* @return the <code>double</code> represented by the bits.
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*/
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public static native double longBitsToDouble (long bits);
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/**
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* Parse the specified <code>String</code> as a <code>double</code>.
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*
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* The number is really read as <em>n * 10<sup>exponent</sup></em>. The
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* first number is <em>n</em>, and if there is an "<code>E</code>"
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* ("<code>e</code>" is also acceptable), then the integer after that is
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* the exponent.
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* <P>
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* Here are the possible forms the number can take:
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* <BR>
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* <TABLE BORDER=1>
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* <TR><TH>Form</TH><TH>Examples</TH></TR>
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* <TR><TD><CODE>[+-]<number>[.]</CODE></TD><TD>345., -10, 12</TD></TR>
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* <TR><TD><CODE>[+-]<number>.<number></CODE></TD><TD>40.2, 80.00, -12.30</TD></TR>
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* <TR><TD><CODE>[+-]<number>[.]E[+-]<number></CODE></TD><TD>80E12, -12e+7, 4.E-123</TD></TR>
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* <TR><TD><CODE>[+-]<number>.<number>E[+-]<number></CODE></TD><TD>6.02e-22, -40.2E+6, 12.3e9</TD></TR>
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* </TABLE>
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*
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* "<code>[+-]</code>" means either a plus or minus sign may go there, or
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* neither, in which case + is assumed.
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* <BR>
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* "<code>[.]</code>" means a dot may be placed here, but is optional.
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* <BR>
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* "<code><number></code>" means a string of digits (0-9), basically
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* an integer. "<code><number>.<number></code>" is basically
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* a real number, a floating-point value.
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* <P>
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*
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* Remember that a <code>double</code> has a limited range. If the
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* number you specify is greater than <code>Double.MAX_VALUE</code> or less
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* than <code>-Double.MAX_VALUE</code>, it will be set at
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* <code>Double.POSITIVE_INFINITY</code> or
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* <code>Double.NEGATIVE_INFINITY</code>, respectively.
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* <P>
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* Note also that <code>double</code> does not have perfect precision. Many
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* numbers cannot be precisely represented. The number you specify
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* will be rounded to the nearest representable value.
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* <code>Double.MIN_VALUE</code> is the margin of error for
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* <code>double</code> values.
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* <P>
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* If an unexpected character is found in the <code>String</code>, a
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* <code>NumberFormatException</code> will be thrown. Spaces are not
|
|
* allowed, and will cause the same exception.
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*
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* @XXX specify where/how we are not in accord with the spec.
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*
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* @param str the <code>String</code> to convert
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* @return the value of the <code>String</code> as a <code>double</code>.
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* @exception NumberFormatException when the string cannot be parsed to a
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* <code>double</code>.
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|
* @exception NullPointerException when the string is null.
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|
* @see #MIN_VALUE
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|
* @see #MAX_VALUE
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|
* @see #POSITIVE_INFINITY
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|
* @see #NEGATIVE_INFINITY
|
|
* @since 1.2
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|
*/
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|
public native static double parseDouble (String s)
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throws NumberFormatException;
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/**
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* Initialize JNI cache. This method is called only by the
|
|
* static initializer when using JNI.
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|
*/
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|
private static native void initIDs ();
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|
}
|