MathLogFunction.java

/**
 *  Copyright (C) 2010 dennis zhuang (killme2008@gmail.com)
 *
 *  This library 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 program; if not, write to the Free Software
 *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 *
 **/
package com.googlecode.aviator.runtime.function.math;

import java.math.BigDecimal;
import java.math.BigInteger;
import java.util.Map;

import com.googlecode.aviator.runtime.function.AbstractFunction;
import com.googlecode.aviator.runtime.function.FunctionUtils;
import com.googlecode.aviator.runtime.type.AviatorDecimal;
import com.googlecode.aviator.runtime.type.AviatorDouble;
import com.googlecode.aviator.runtime.type.AviatorObject;
import com.googlecode.aviator.utils.TypeUtils;


/**
 * math.log(d) function
 * 
 * @author dennis
 * 
 */
public class MathLogFunction extends AbstractFunction {

    @Override
    public AviatorObject call(Map<String, Object> env, AviatorObject arg1) {

        Number num = FunctionUtils.getNumberValue(arg1, env);
        if (TypeUtils.isDecimal(num)) {
            return new AviatorDecimal(TypeUtils.ln((BigDecimal) num));
        }
        else if (TypeUtils.isBigInt(num)) {
            return new AviatorDecimal(TypeUtils.ln(new BigDecimal((BigInteger) num)));
        }
        else {
            return new AviatorDouble(Math.log(num.doubleValue()));
        }

    }


    @Override
    public String getName() {
        return "math.log";
    }

}