libjava/java/lang/VMDouble.java

   1 /* VMDouble.java -- VM Specific Double methods
   2    Copyright (C) 2003, 2005, 2006  Free Software Foundation
   3
   4 This file is part of GNU Classpath.
   5
   6 GNU Classpath is free software; you can redistribute it and/or modify
   7 it under the terms of the GNU General Public License as published by
   8 the Free Software Foundation; either version 2, or (at your option)
   9 any later version.
  10
  11 GNU Classpath is distributed in the hope that it will be useful, but
  12 WITHOUT ANY WARRANTY; without even the implied warranty of
  13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14 General Public License for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with GNU Classpath; see the file COPYING.  If not, write to the
  18 Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  19 02110-1301 USA.
  20
  21 Linking this library statically or dynamically with other modules is
  22 making a combined work based on this library.  Thus, the terms and
  23 conditions of the GNU General Public License cover the whole
  24 combination.
  25
  26 As a special exception, the copyright holders of this library give you
  27 permission to link this library with independent modules to produce an
  28 executable, regardless of the license terms of these independent
  29 modules, and to copy and distribute the resulting executable under
  30 terms of your choice, provided that you also meet, for each linked
  31 independent module, the terms and conditions of the license of that
  32 module.  An independent module is a module which is not derived from
  33 or based on this library.  If you modify this library, you may extend
  34 this exception to your version of the library, but you are not
  35 obligated to do so.  If you do not wish to do so, delete this
  36 exception statement from your version. */
  37
  38 package java.lang;
  39
  40 import gnu.classpath.Configuration;
  41
  42 /*
  43  * This class is a reference version, mainly for compiling a class library
  44  * jar.  It is likely that VM implementers replace this with their own
  45  * version that can communicate effectively with the VM.
  46  */
  47
  48 /**
  49  * Code relocated from java.lang.Double by
  50  * @author Dave Grove (groved@us.ibm.com)
  51  */
  52 final class VMDouble
  53 {
  54   /**
  55    * Convert the double to the IEEE 754 floating-point "double format" bit
  56    * layout. Bit 63 (the most significant) is the sign bit, bits 62-52
  57    * (masked by 0x7ff0000000000000L) represent the exponent, and bits 51-0
  58    * (masked by 0x000fffffffffffffL) are the mantissa. This function
  59    * collapses all versions of NaN to 0x7ff8000000000000L. The result of this
  60    * function can be used as the argument to
  61    * <code>Double.longBitsToDouble(long)</code> to obtain the original
  62    * <code>double</code> value.
  63    *
  64    * @param value the <code>double</code> to convert
  65    * @return the bits of the <code>double</code>
  66    * @see #longBitsToDouble(long)
  67    */
  68   public static native long doubleToLongBits(double value);
  69
  70   /**
  71    * Convert the double to the IEEE 754 floating-point "double format" bit
  72    * layout. Bit 63 (the most significant) is the sign bit, bits 62-52
  73    * (masked by 0x7ff0000000000000L) represent the exponent, and bits 51-0
  74    * (masked by 0x000fffffffffffffL) are the mantissa. This function
  75    * leaves NaN alone, rather than collapsing to a canonical value. The
  76    * result of this function can be used as the argument to
  77    * <code>Double.longBitsToDouble(long)</code> to obtain the original
  78    * <code>double</code> value.
  79    *
  80    * @param value the <code>double</code> to convert
  81    * @return the bits of the <code>double</code>
  82    * @see #longBitsToDouble(long)
  83    */
  84   public static native long doubleToRawLongBits(double value);
  85
  86   /**
  87    * Convert the argument in IEEE 754 floating-point "double format" bit
  88    * layout to the corresponding float. Bit 63 (the most significant) is the
  89    * sign bit, bits 62-52 (masked by 0x7ff0000000000000L) represent the
  90    * exponent, and bits 51-0 (masked by 0x000fffffffffffffL) are the mantissa.
  91    * This function leaves NaN alone, so that you can recover the bit pattern
  92    * with <code>Double.doubleToRawLongBits(double)</code>.
  93    *
  94    * @param bits the bits to convert
  95    * @return the <code>double</code> represented by the bits
  96    * @see #doubleToLongBits(double)
  97    * @see #doubleToRawLongBits(double)
  98    */
  99   public static native double longBitsToDouble(long bits);
 100
 101   /**
 102    * Helper method to convert to string.
 103    *
 104    * @param d the double to convert
 105    * @param isFloat true if the conversion is requested by Float (results in
 106    *        fewer digits)
 107    */
 108   public static native String toString(double d, boolean isFloat);
 109
 110   public static native double parseDouble(String str);
 111 }