/* Copyright (c) 2002-2011 by XMLVM.org
*
* Project Info: http://www.xmlvm.org
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation; either version 2.1 of the License, or
* (at your option) any later version.
*
* This library 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 Lesser General Public
* License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
* USA.
*/
package org.xmlvm.proc.out;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import org.jdom.Document;
import org.jdom.Element;
import org.xmlvm.main.Arguments;
import org.xmlvm.proc.BundlePhase1;
import org.xmlvm.proc.BundlePhase2;
import org.xmlvm.proc.XmlvmProcessImpl;
import org.xmlvm.proc.XmlvmResource;
import org.xmlvm.proc.XmlvmResource.XmlvmConstantStringElement;
/**
* Optimizes the DEXMLVM output.
*/
public class OptimizationOutputProcess extends XmlvmProcessImpl
{
/**
* Helper class representing one entry of the string constant pool. Used by
* method <code>generateStringConstantPool</code>.
*/
class ConstantPoolEntry
{
public int id;
public int length;
public String encodedString;
public String escapedString;
public ConstantPoolEntry(int id, int len, String escapedConstant, String encodedConstant)
{
this.id= id;
this.length= len;
this.escapedString= escapedConstant;
this.encodedString= encodedConstant;
}
public boolean equals(Object other)
{
if (!(other instanceof ConstantPoolEntry))
{
return false;
}
ConstantPoolEntry o= (ConstantPoolEntry) other;
return other instanceof ConstantPoolEntry && this.id == o.id && this.encodedString.equals(o.encodedString);
}
}
/**
* Initializes the {@link OptimizationOutputProcess}.
*/
public OptimizationOutputProcess(Arguments arguments)
{
super(arguments);
addSupportedInput(DEXmlvmOutputProcess.class);
}
public boolean processPhase1(BundlePhase1 bundle)
{
return true;
}
public boolean processPhase2(BundlePhase2 bundle)
{
generateStringConstantPool(bundle);
return true;
}
/**
* Generates the string constant pool for this application. This method
* iterates over all <code>XmlvmResources</code> and builds up a list of
* unique string constants. Those string constants are added as another
* <code>XmlvmResource</code> (of type <code>CONST_POOL</code>) to the
* bundle. The XML markup of the constant pool looks as follows:
*
* <pre>
* <vm:constant-pool>
* <entry id="..." length="..." encoded-constant="..." escaped-constant="..."/>
* ...
* </constant-pool>
* </pre>
*/
private void generateStringConstantPool(BundlePhase2 bundle)
{
List<ConstantPoolEntry> constantPool= new ArrayList<ConstantPoolEntry>();
Map<String, Integer> constantPoolIDs= new HashMap<String, Integer>();
for (XmlvmResource resource : bundle.getResources())
{
List<XmlvmConstantStringElement> instructions= new ArrayList<XmlvmConstantStringElement>();
resource.collectInstructions(instructions);
for (XmlvmConstantStringElement inst : instructions)
{
String escapedConstant= inst.getEscapedStringConstant();
String encodedConstant= inst.getEncodedStringConstant();
int len= inst.getLength();
int id= -1;
if (constantPoolIDs.containsKey(encodedConstant))
{
id= constantPoolIDs.get(encodedConstant);
}
else
{
id= constantPool.size();
ConstantPoolEntry entry= new ConstantPoolEntry(id, len, escapedConstant, encodedConstant);
constantPool.add(entry);
constantPoolIDs.put(encodedConstant, id);
}
inst.setContantPoolID(id);
}
}
Element xmlRoot= new Element("constant-pool", XmlvmResource.nsXMLVM);
for (ConstantPoolEntry entry : constantPool)
{
Element xmlEntry= new Element("entry", XmlvmResource.nsXMLVM);
xmlEntry.setAttribute("id", "" + entry.id);
xmlEntry.setAttribute("length", "" + entry.length);
xmlEntry.setAttribute("escaped-constant", entry.escapedString);
xmlEntry.setAttribute("encoded-constant", entry.encodedString);
xmlRoot.addContent(xmlEntry);
}
XmlvmResource resource= new XmlvmResource(XmlvmResource.Type.CONST_POOL, new Document(xmlRoot));
bundle.addAdditionalResource(resource);
}
}