AppsheetEpplus/FormulaParsing/ExcelUtilities/ExcelAddressUtil.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)
 *******************************************************************************/

namespace AppsheetEpplus;

public static class ExcelAddressUtil {
  private static readonly char[] SheetNameInvalidChars = ['?', ':', '*', '/', '\\'];

  public static bool IsValidAddress(string token) {
    int ix;
    if (token[0] == '\'') {
      ix = token.LastIndexOf('\'');
      if (ix > 0 && ix < token.Length - 1 && token[ix + 1] == '!') {
        if (token.IndexOfAny(SheetNameInvalidChars, 1, ix - 1) > 0) {
          return false;
        }
        token = token.Substring(ix + 2);
      } else {
        return false;
      }
    } else if ((ix = token.IndexOf('!')) > 1) {
      if (token.IndexOfAny(SheetNameInvalidChars, 0, token.IndexOf('!')) > 0) {
        return false;
      }
      token = token.Substring(token.IndexOf('!') + 1);
    }
    return ExcelCellBase.IsValidAddress(token);
  }
}