Calculate checksum
using fileStream object in dotnet
using System;
using System.Reflection;
using System.Security.Cryptography;
using System.Text;
using System.IO;
using System.IO.Abstractions;
namespace Helper.Utility
{
//Class CrcUtil.cs used
get filestream using filepath for calculating checksum
public class CrcUtil
{
private readonly IFileSystem _fileSystem;
public CrcUtil(IFileSystem fileSystem)
{
_fileSystem = fileSystem;
}
public string GetCrcCode(string filePath)
{
try
{
using (var stream = _fileSystem.File.Open(filePath, FileMode.Open, FileAccess.Read, FileShare.Read))
{
return GetCrcCode(stream);
}
}
catch (Exception ex)
{
//
SsiLogger.Logger.Error("Exception occured in CrcUtil {0} for file
{1}", ex.Message, filePath);
//
SsiLogger.Logger.Debug(ex);
throw;
}
}
public string GetCrcCode(Stream fileStream)
{
try
{
return Md5HashGenerator.GenerateKey(fileStream);
}
catch (Exception ex)
{
//
SsiLogger.Logger.Error("Exception occured in CrcUtil {0}",
ex.Message);
//
SsiLogger.Logger.Debug(ex);
throw;
}
}
}
//Class Md5HashGenerator.cs
used for calculating checksum of passed filestream
public class Md5HashGenerator
{
public static String GenerateKey(Stream sourceObject)
{
//Catch
unuseful parameter values
if (sourceObject == null)
{
throw new ArgumentNullException("sourceObject");
}
//We
determine if the passed object is really serializable.
try
{
//Now
we begin to do the real work.
var hashString = ComputeHash(sourceObject);
return hashString;
}
catch (AmbiguousMatchException ame)
{
throw new ApplicationException(string.Format("Could not
definitly decide if object is serializable. Message:{0}", ame.Message));
}
catch (Exception ex)
{
//
SsiLogger.Logger.Error("Exception occured in Md5HashGenerator {0}",
ex.Message);
//
SsiLogger.Logger.Debug(ex);
throw;
}
}
private static string ComputeHash(Stream objectAsBytes)
{
MD5 md5 = new MD5CryptoServiceProvider();
try
{
var result = md5.ComputeHash(objectAsBytes);
//
Build the final string by converting each byte
//
into hex and appending it to a StringBuilder
var stringBuilder = new StringBuilder();
foreach (var data in result)
{
stringBuilder.Append(data.ToString("X2"));
}
//
And return it
return stringBuilder.ToString();
}
catch (ArgumentNullException)
{
//If
something occured during serialization, this method is called with an null
argument.
//
SsiLogger.Logger.Error("Hash has not been generated.");
return null;
}
catch (Exception ex)
{
//
SsiLogger.Logger.Error("Exception occured in Md5HashGenerator {0}",
ex.Message);
//
SsiLogger.Logger.Debug(ex);
throw;
}
}
}
}
