Compares the content of 2 files : File Util « File Stream « C# / C Sharp

1. C# / C Sharp
2. File Stream
3. File Util

Compares the content of 2 files

   

#region License and Copyright
/* -------------------------------------------------------------------------
 * Dotnet Commons IO
 *
 *
 * 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. 
 *
 * You should have received a copy of the GNU Lesser General Public License 
 * along with this library; if not, write to the 
 * 
 * Free Software Foundation, Inc., 
 * 59 Temple Place, 
 * Suite 330, 
 * Boston, 
 * MA 02111-1307 
 * USA 
 * 
 * -------------------------------------------------------------------------
 */
#endregion

using System;
using System.Collections;
using System.Globalization;
using System.IO;

namespace Dotnet.Commons.IO
{
    class MainClass{
        /// ---------------------------------------------------------------
        /// <summary>
        /// This method compares the content of 2 files. A return value of true
        /// indicates that the contents of the files
        /// are the same. A return value of false indicates that the 
        /// files are not the same.
    /// </summary>
    /// <param name="firstFile">first file to be compared against the second</param>
    /// <param name="secondFile">second file to be compared against the first</param>
    /// <returns>true if they are the same, false otherwise</returns>
        /// <remarks>
        /// This method has been modified to increase the speed in which this
        /// file comparing operation performs.
        /// 
        /// The MSDN knowledge base:
        /// How to create a File-Compare function in Visual C#
        /// http://support.microsoft.com/default.aspx?scid=kb;en-us;320348
        /// was used to assist in speeding up this operation.
        /// </remarks>
        /// ---------------------------------------------------------------
    public static bool Compare(FileInfo firstFile, FileInfo secondFile)
    {
      if (!firstFile.Exists) 
      {
        string message = "File '" + firstFile.FullName + "' does not exist";
        throw new FileNotFoundException(message);
      }

      if (!secondFile.Exists) 
      {
        string message = "File '" + secondFile.FullName + "' does not exist";
        throw new FileNotFoundException(message);
      }


      // Check Each byte
      FileStream fs1 = new FileStream(firstFile.FullName, FileMode.Open, FileAccess.Read);
            FileStream fs2 = new FileStream(secondFile.FullName, FileMode.Open, FileAccess.Read);
                     
            // Check the file sizes. If they are not the same, the files 
            // are not the same.
            if (fs1.Length != fs2.Length)
            {
                // Close the file
                fs1.Close();
                fs2.Close();

                // Return false to indicate files are different
                return false;
            }

            int file1byte;
            int file2byte;

            // Read and compare a byte from each file until either a
            // non-matching set of bytes is found or until the end of
            // file1 is reached.
            do
            {
                // Read one byte from each file.
                file1byte = fs1.ReadByte();
                file2byte = fs2.ReadByte();
            }
            while ((file1byte == file2byte) && (file1byte != -1));

            // Close the files.
            fs1.Close();
            fs2.Close();

            // Return the success of the comparison. "file1byte" is 
            // equal to "file2byte" at this point only if the files are 
            // the same.
            return ((file1byte - file2byte) == 0);

    }

        


        /// <summary>
        /// Compare the contents two files.
        /// </summary>
        /// <param name="firstFile">first file to be compared against the second</param>
        /// <param name="secondFile">second file to be compared against the first</param>
        /// <returns>true if they are the same, false otherwise</returns>
        public static bool Compare(string firstFile, string secondFile)
        {
            FileInfo fiFirstFile = new FileInfo(firstFile);
            FileInfo fiSecondFile = new FileInfo(secondFile);

            return Compare(fiFirstFile, fiSecondFile);
        }
   }
}

   
    
    
  

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