/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 * 
 *   http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

package org.apache.sysml.parser;


public abstract class LiveVariableAnalysis 
{

		
	VariableSet _read;
	VariableSet _updated;
	VariableSet _gen;
	VariableSet _kill;
	VariableSet _liveIn;
	VariableSet _liveOut;
	boolean _initialized = false;
	
	VariableSet _warnSet;	// variables that may not be initialized
							// applicable for control blocks
		
	public VariableSet variablesRead(){
		return _read;
	}
	
	public VariableSet variablesUpdated() {
		return _updated;
	}
	
	public VariableSet getWarn(){
		return _warnSet;
	}
	
	public VariableSet liveIn() {
		return _liveIn;
	}
	
	public VariableSet liveOut() {
		return _liveOut;
	}
	
	public VariableSet getKill(){
		return _kill;
	}
	
	public void setLiveOut(VariableSet lo){
		_liveOut = lo;
	}
	
	public void setLiveIn(VariableSet li){
		_liveIn = li;
	}
	
	public void setUpdatedVariables( VariableSet vars ){
		_updated = vars;
	}
	
	public void setReadVariables( VariableSet vars ){
		_read = vars;
	}
	
	public abstract VariableSet initializeforwardLV(VariableSet activeIn) throws LanguageException;
	public abstract VariableSet initializebackwardLV(VariableSet loPassed) throws LanguageException;
	public abstract VariableSet analyze(VariableSet loPassed) throws LanguageException;
	
	public void updateLiveVariablesOut(VariableSet liveOut){
		 updateLiveVariables(_liveOut,liveOut);
	}
	
	private void updateLiveVariables(VariableSet origVars, VariableSet newVars){
		for (String var : newVars.getVariables().keySet()){
			if (origVars.containsVariable(var)){
				DataIdentifier varId = newVars.getVariable(var);
				if (varId != null){
					origVars.addVariable(var, varId);
				}
			}
		}
	}
}