EPPlus/FormulaParsing/Excel/Functions/Math/RandBetween.cs

/* Copyright (C) 2011  Jan Källman
 *
 * 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.
 *
 * The GNU Lesser General Public License can be viewed at http://www.opensource.org/licenses/lgpl-license.php
 * If you unfamiliar with this license or have questions about it, here is an http://www.gnu.org/licenses/gpl-faq.html
 *
 * All code and executables are provided "as is" with no warranty either express or implied.
 * The author accepts no liability for any damage or loss of business that this product may cause.
 *
 * Code change notes:
 *
 * Author							Change						Date
 *******************************************************************************
 * Mats Alm   		                Added		                2013-12-03
 *******************************************************************************/

using System.Collections.Generic;
using OfficeOpenXml.FormulaParsing.ExpressionGraph;

namespace OfficeOpenXml.FormulaParsing.Excel.Functions.Math;

public class RandBetween : ExcelFunction {
  public override CompileResult Execute(
      IEnumerable<FunctionArgument> arguments,
      ParsingContext context) {
    ValidateArguments(arguments, 2);
    var low = ArgToDecimal(arguments, 0);
    var high = ArgToDecimal(arguments, 1);
    var rand = new Rand().Execute(new FunctionArgument[0], context).Result;
    var randPart = (CalulateDiff(high, low) * (double)rand) + 1;
    randPart = System.Math.Floor(randPart);
    return CreateResult(low + randPart, DataType.Integer);
  }

  private double CalulateDiff(double high, double low) {
    if (high > 0 && low < 0) {
      return high + low * -1;
    }
    if (high < 0 && low < 0) {
      return high * -1 - low * -1;
    }
    return high - low;
  }
}