EPPlus/FormulaParsing/Excel/Functions/Text/Mid.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;
using System.Collections.Generic;
using OfficeOpenXml.FormulaParsing.ExpressionGraph;

namespace OfficeOpenXml.FormulaParsing.Excel.Functions.Text;

public class Mid : ExcelFunction {
  public override CompileResult Execute(
      IEnumerable<FunctionArgument> arguments,
      ParsingContext context) {
    ValidateArguments(arguments, 3);
    var text = ArgToString(arguments, 0);
    var startIx = ArgToInt(arguments, 1);
    var length = ArgToInt(arguments, 2);
    if (startIx <= 0) {
      throw (new ArgumentException("Argument start can't be less than 1"));
    }
    //Allow overflowing start and length
    if (startIx > text.Length) {
      return CreateResult("", DataType.String);
    }
    var result = text.Substring(
        startIx - 1,
        startIx - 1 + length < text.Length ? length : text.Length - startIx + 1);
    return CreateResult(result, DataType.String);
  }
}