/*
* ProGuard -- shrinking, optimization, obfuscation, and preverification
* of Java bytecode.
*
* Copyright (c) 2002-2011 Eric Lafortune (eric@graphics.cornell.edu)
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the Free
* Software Foundation; either version 2 of the License, or (at your option)
* any later version.
*
* This program 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 for
* more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
package proguard.evaluation;
import proguard.evaluation.value.Value;
/**
* This Variables class saves additional information with variables, to keep
* track of their origins.
* <p>
* The Variables class stores a given producer Value along with each Value it
* stores. It then generalizes a given collected Value with the producer Value
* of each Value it loads. The producer Value and the initial collected Value
* can be set; the generalized collected Value can be retrieved.
*
* @author Eric Lafortune
*/
public class TracedVariables extends Variables
{
public static final int NONE = -1;
private Value producerValue;
private Variables producerVariables;
/**
* Creates a new TracedVariables with a given size.
*/
public TracedVariables(int size)
{
super(size);
producerVariables = new Variables(size);
}
/**
* Creates a new TracedVariables that is a copy of the given TracedVariables.
*/
public TracedVariables(TracedVariables tracedVariables)
{
super(tracedVariables);
producerVariables = new Variables(tracedVariables.producerVariables);
}
/**
* Sets the Value that will be stored along with all store instructions.
*/
public void setProducerValue(Value producerValue)
{
this.producerValue = producerValue;
}
/**
* Gets the producer Value for the specified variable, without disturbing it.
* @param index the variable index.
* @return the producer value of the given variable.
*/
public Value getProducerValue(int index)
{
return producerVariables.getValue(index);
}
/**
* Sets the given producer Value for the specified variable, without
* disturbing it.
* @param index the variable index.
* @param value the producer value to set.
*/
public void setProducerValue(int index, Value value)
{
producerVariables.store(index, value);
}
// Implementations for Variables.
public void reset(int size)
{
super.reset(size);
producerVariables.reset(size);
}
public void initialize(TracedVariables other)
{
super.initialize(other);
producerVariables.initialize(other.producerVariables);
}
public boolean generalize(TracedVariables other,
boolean clearConflictingOtherVariables)
{
boolean variablesChanged = super.generalize(other, clearConflictingOtherVariables);
boolean producersChanged = producerVariables.generalize(other.producerVariables, clearConflictingOtherVariables);
/* consumerVariables.generalize(other.consumerVariables)*/
// Clear any traces if a variable has become null.
if (variablesChanged)
{
for (int index = 0; index < size; index++)
{
if (values[index] == null)
{
producerVariables.values[index] = null;
if (clearConflictingOtherVariables)
{
other.producerVariables.values[index] = null;
}
}
}
}
return variablesChanged || producersChanged;
}
public void store(int index, Value value)
{
// Store the value itself in the variable.
super.store(index, value);
// Store the producer value in its producer variable.
producerVariables.store(index, producerValue);
// Account for the extra space required by Category 2 values.
if (value.isCategory2())
{
producerVariables.store(index+1, producerValue);
}
}
// Implementations for Object.
public boolean equals(Object object)
{
if (object == null ||
this.getClass() != object.getClass())
{
return false;
}
TracedVariables other = (TracedVariables)object;
return super.equals(object) &&
this.producerVariables.equals(other.producerVariables);
}
public int hashCode()
{
return super.hashCode() ^
producerVariables.hashCode();
}
public String toString()
{
StringBuffer buffer = new StringBuffer();
for (int index = 0; index < this.size(); index++)
{
Value value = this.values[index];
Value producerValue = producerVariables.getValue(index);
buffer = buffer.append('[')
.append(producerValue == null ? "empty:" : producerValue.toString())
.append(value == null ? "empty" : value.toString())
.append(']');
}
return buffer.toString();
}
}