AppsheetEpplus/FormulaParsing/ExcelUtilities/CellReferenceProvider.cs

/*******************************************************************************
 * You may amend and distribute as you like, but don't remove this header!
 *
 * EPPlus provides server-side generation of Excel 2007/2010 spreadsheets.
 * See http://www.codeplex.com/EPPlus for details.
 *
 * 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       		        2013-03-01 (Prior file history on https://github.com/swmal/ExcelFormulaParser)
 *******************************************************************************/

using System.Collections.Generic;
using System.Linq;

namespace AppsheetEpplus;

public class CellReferenceProvider {
  public virtual IEnumerable<string> GetReferencedAddresses(
      string cellFormula,
      ParsingContext context) {
    var resultCells = new List<string>();
    var r = context.Configuration.Lexer.Tokenize(
        cellFormula,
        context.Scopes.Current.Address.Worksheet);
    var toAddresses = r.Where(x => x.TokenType == TokenType.ExcelAddress);
    foreach (var toAddress in toAddresses) {
      var rangeAddress = context.RangeAddressFactory.Create(toAddress.Value);
      var rangeCells = new List<string>();
      if (rangeAddress.FromRow < rangeAddress.ToRow || rangeAddress.FromCol < rangeAddress.ToCol) {
        for (var col = rangeAddress.FromCol; col <= rangeAddress.ToCol; col++) {
          for (var row = rangeAddress.FromRow; row <= rangeAddress.ToRow; row++) {
            resultCells.Add(context.RangeAddressFactory.Create(col, row).Address);
          }
        }
      } else {
        rangeCells.Add(toAddress.Value);
      }
      resultCells.AddRange(rangeCells);
    }
    return resultCells;
  }
}