org.apache.poi.ss.formula.functions.Gcd Maven / Gradle / Ivy

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   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
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       http://www.apache.org/licenses/LICENSE-2.0

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   distributed under the License is distributed on an "AS IS" BASIS,
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package org.apache.poi.ss.formula.functions;

import org.apache.commons.math3.util.ArithmeticUtils;
import org.apache.poi.ss.formula.OperationEvaluationContext;
import org.apache.poi.ss.formula.eval.ErrorEval;
import org.apache.poi.ss.formula.eval.EvaluationException;
import org.apache.poi.ss.formula.eval.NumberEval;
import org.apache.poi.ss.formula.eval.OperandResolver;
import org.apache.poi.ss.formula.eval.ValueEval;

import java.util.ArrayList;


/**
 * Implementation for Excel GCD() function.
 * 
 *   Syntax:
 GCD  (number, ...)

 * 
 * 
 *   Returns the greatest common divisor of two or more integers. The greatest common divisor is the largest integer that divides both number1 and number2 without a remainder.
 * 
 * 
 *   See https://support.microsoft.com/en-us/office/gcd-function-d5107a51-69e3-461f-8e4c-ddfc21b5073a
 * 
 */
public class Gcd implements FreeRefFunction {

    public static final Gcd instance = new Gcd();

    private static final long MAX_INPUT = (long)Math.pow(2, 53);

    @Override
    public ValueEval evaluate(ValueEval[] args, OperationEvaluationContext ec) {
        if (args.length < 1) {
            return ErrorEval.VALUE_INVALID;
        } else if (args.length == 1) {
            try {
                ValueEval v1 = OperandResolver.getSingleValue(args[0], ec.getRowIndex(), ec.getColumnIndex());
                double d = OperandResolver.coerceValueToDouble(v1);
                if (isInvalidInput(d)) {
                    return ErrorEval.NUM_ERROR;
                }
                return new NumberEval((long)d);
            } catch (EvaluationException ee) {
                return ErrorEval.VALUE_INVALID;
            }
        } else {
            try {
                ArrayList evals = new ArrayList<>();
                for (ValueEval arg : args) {
                    ValueEval ve = OperandResolver.getSingleValue(arg, ec.getRowIndex(), ec.getColumnIndex());
                    double d = OperandResolver.coerceValueToDouble(ve);
                    if (isInvalidInput(d)) {
                        return ErrorEval.NUM_ERROR;
                    }
                    evals.add((long) d);
                }
                long result = evals.get(0);
                for (int i = 1; i < evals.size(); i++) {
                    result = ArithmeticUtils.gcd(result, evals.get(i));
                }
                return new NumberEval(result);
            } catch (EvaluationException ee) {
                return ErrorEval.VALUE_INVALID;
            }
        }
    }

    private boolean isInvalidInput(double d) {
        return (d < 0 || d > MAX_INPUT);
    }
}