Switch.java

package com.dragome.compiler.graph.transformation;

import java.util.ArrayList;
import java.util.List;

import com.dragome.compiler.ast.Block;
import com.dragome.compiler.ast.NumberLiteral;
import com.dragome.compiler.ast.SwitchCase;
import com.dragome.compiler.ast.SwitchStatement;
import com.dragome.compiler.graph.Edge;
import com.dragome.compiler.graph.Node;
import com.dragome.compiler.graph.SwitchEdge;

public class Switch extends Transformation
{

	private List<Node> caseGroups= new ArrayList<Node>();

	private List<List<NumberLiteral>> caseGroupExpressions= new ArrayList<List<NumberLiteral>>();

	public boolean applies_()
	{
		return header.isSwitchHeader;
	}

	private void removeFallThroughEdgesl()
	{
		Edge prevPotentialFallThroughEdge= null;

		for (Edge e : header.getOutEdges())
		{
			if (!(e instanceof SwitchEdge))
				continue;

			SwitchEdge edge= (SwitchEdge) e;
			Node caseGroup= edge.target;

			if (prevPotentialFallThroughEdge != null && prevPotentialFallThroughEdge.target == caseGroup)
			{

				graph.removeEdge(prevPotentialFallThroughEdge);
			}

			prevPotentialFallThroughEdge= caseGroup.getLocalOutEdgeOrNull();
		}
	}

	void apply_()
	{
		removeFallThroughEdgesl();

		for (Edge e : new ArrayList<Edge>(header.getOutEdges()))
		{
			if (!(e instanceof SwitchEdge))
				continue;

			SwitchEdge edge= (SwitchEdge) e;
			Node caseGroup= edge.target;
			caseGroups.add(caseGroup);
			caseGroupExpressions.add(edge.expressions);
			graph.rerootOutEdges(caseGroup, newNode, true);
			graph.removeOutEdges(caseGroup);
			graph.removeInEdges(caseGroup);
			graph.removeNode(caseGroup);
		}
	}

	void rollOut_(Block block)
	{
		SwitchStatement switchStmt= new SwitchStatement();
		switchStmt.setExpression(header.switchExpression);

		for (int i= 0; i < caseGroups.size(); i++)
		{
			Node scNode= caseGroups.get(i);
			SwitchCase switchCase= new SwitchCase(scNode.getInitialPc());
			switchCase.setExpressions(caseGroupExpressions.get(i));
			switchStmt.appendChild(switchCase);

			graph.rollOut(scNode, switchCase);
		}

		block.appendChild(switchStmt);
	}

	public String toString()
	{
		String s= super.toString() + "(" + header;
		for (int i= 0; i < caseGroups.size(); i++)
		{
			s+= ", " + caseGroups.get(i);
		}
		return s + ")";
	}
}