org.eclipse.linuxtools.ctf.core/src/org/eclipse/linuxtools/ctf/core/event/types/FloatDefinition.java

   1 /*******************************************************************************
   2  * Copyright (c) 2011, 2013 Ericsson, Ecole Polytechnique de Montreal and others
   3  *
   4  * All rights reserved. This program and the accompanying materials are made
   5  * available under the terms of the Eclipse Public License v1.0 which
   6  * accompanies this distribution, and is available at
   7  * http://www.eclipse.org/legal/epl-v10.html
   8  *
   9  * Contributors: Matthew Khouzam - Initial API and implementation
  10  *******************************************************************************/
  11
  12 package org.eclipse.linuxtools.ctf.core.event.types;
  13
  14 import org.eclipse.linuxtools.ctf.core.event.io.BitBuffer;
  15 import org.eclipse.linuxtools.ctf.core.trace.CTFReaderException;
  16
  17 /**
  18  * A CTF float definition.
  19  *
  20  * The definition of a floating point basic data type. It will take the data
  21  * from a trace and store it (and make it fit) as a double.
  22  *
  23  * @version 1.0
  24  * @author Matthew Khouzam
  25  * @author Simon Marchi
  26  */
  27 public class FloatDefinition extends Definition {
  28     // ------------------------------------------------------------------------
  29     // Attributes
  30     // ------------------------------------------------------------------------
  31
  32     private final FloatDeclaration declaration;
  33     private double value;
  34
  35     // ------------------------------------------------------------------------
  36     // Constructors
  37     // ------------------------------------------------------------------------
  38
  39     /**
  40      * Constructor
  41      *
  42      * @param declaration
  43      *            the parent declaration
  44      * @param definitionScope
  45      *            the parent scope
  46      * @param fieldName
  47      *            the field name
  48      */
  49     public FloatDefinition(FloatDeclaration declaration,
  50             IDefinitionScope definitionScope, String fieldName) {
  51         super(definitionScope, fieldName);
  52         this.declaration = declaration;
  53     }
  54
  55     // ------------------------------------------------------------------------
  56     // Getters/Setters/Predicates
  57     // ------------------------------------------------------------------------
  58
  59     /**
  60      * The value of a float stored, fit into a double. This should be extended
  61      * for exotic floats if this is necessary.
  62      *
  63      * @return the value of the float field fit into a double.
  64      */
  65     public double getValue() {
  66         return value;
  67     }
  68
  69     /**
  70      * Sets the value of the float
  71      *
  72      * @param val
  73      *            the value of the float
  74      */
  75     public void setValue(double val) {
  76         value = val;
  77     }
  78
  79     @Override
  80     public FloatDeclaration getDeclaration() {
  81         return declaration;
  82     }
  83
  84     // ------------------------------------------------------------------------
  85     // Operations
  86     // ------------------------------------------------------------------------
  87
  88     @Override
  89     public void read(BitBuffer input) throws CTFReaderException {
  90         /* Offset the buffer position wrt the current alignment */
  91         alignRead(input, this.declaration);
  92         final int exp = declaration.getExponent();
  93         final int mant = declaration.getMantissa();
  94
  95         if ((exp + mant) == 32) {
  96             value = readRawFloat32(input, mant, exp);
  97         } else if ((exp + mant) == 64) {
  98             value = readRawFloat64(input, mant, exp);
  99         } else {
 100             value = Double.NaN;
 101         }
 102     }
 103
 104     private static double readRawFloat64(BitBuffer input, final int manBits,
 105             final int expBits) throws CTFReaderException {
 106         long temp = input.get(64, false);
 107         return createFloat(temp, manBits - 1, expBits);
 108     }
 109
 110     /**
 111      * @param rawValue
 112      * @param manBits
 113      * @param expBits
 114      */
 115     private static double createFloat(long rawValue, final int manBits,
 116             final int expBits) {
 117         long manShift = 1L << (manBits);
 118         long manMask = manShift - 1;
 119         long expMask = (1L << expBits) - 1;
 120
 121         int exp = (int) ((rawValue >> (manBits)) & expMask) + 1;
 122         long man = (rawValue & manMask);
 123         final int offsetExponent = exp - (1 << (expBits - 1));
 124         double expPow = Math.pow(2.0, offsetExponent);
 125         double ret = man * 1.0f;
 126         ret /= manShift;
 127         ret += 1.0;
 128         ret *= expPow;
 129         return ret;
 130     }
 131
 132     private static double readRawFloat32(BitBuffer input, final int manBits,
 133             final int expBits) throws CTFReaderException {
 134         long temp = input.get(32, false);
 135         return createFloat(temp, manBits - 1, expBits);
 136     }
 137
 138     @Override
 139     public String toString() {
 140         return String.valueOf(value);
 141     }
 142 }