/// <summary>
/// Reset values to defaults
/// </summary>
/// <remarks>HashType will be Undefined</remarks>
public void Clear()
{
FileSize = 0;
FileDateUtc = DateTime.MinValue;
HashType = HashTypeConstants.Undefined;
HashValue = string.Empty;
}
/// <summary>
/// Creates a .hashcheck file for the specified file
/// The file will be created in the same directory as the data file, and will contain size, modification_date_utc, and hash
/// </summary>
/// <param name="dataFilePath">File path to hash</param>
/// <param name="hashType">Hash type</param>
/// <param name="hashValue">Output: the computed file hash</param>
/// <param name="warningMessage">Output: warning message</param>
/// <returns>The full path to the .hashcheck file; empty string if a problem</returns>
/// <remarks></remarks>
public static string CreateHashcheckFile(
string dataFilePath,
HashTypeConstants hashType,
out string hashValue,
out string warningMessage)
{
if (!File.Exists(dataFilePath))
{
hashValue = string.Empty;
warningMessage = "Cannot compute .hashcheck file; source file not found: " + dataFilePath;
return(string.Empty);
}
hashValue = ComputeFileHash(dataFilePath, hashType);
try
{
var hashcheckFilePath = CreateHashcheckFileWithHash(dataFilePath, hashType, hashValue, out warningMessage);
return(hashcheckFilePath);
}
catch (Exception ex)
{
// Treat this as a non-critical error
warningMessage = string.Format("Unable to create the .hashcheck file for source file {0}: {1}",
dataFilePath, ex.Message);
return(string.Empty);
}
}
/// <summary>
/// Computes the hash for a file
/// </summary>
/// <param name="filePath"></param>
/// <param name="hashType">Hash type</param>
/// <returns>Hash value</returns>
public static string ComputeFileHash(string filePath, HashTypeConstants hashType)
{
if (hashType == HashTypeConstants.Undefined)
{
hashType = HashTypeConstants.SHA1;
}
switch (hashType)
{
case HashTypeConstants.CRC32:
return(ComputeFileHashCrc32(filePath));
case HashTypeConstants.MD5:
return(ComputeFileHashMD5(filePath));
case HashTypeConstants.SHA1:
return(ComputeFileHashSha1(filePath));
default:
throw new ArgumentOutOfRangeException(nameof(hashType), "Unknown hash type");
}
}
/// <summary>
/// Read the data in an existing hashcheck file
/// </summary>
/// <param name="hashCheckFilePath"></param>
/// <param name="assumedHashType">
/// Hashtype to assume if the .hashcheck file does not have "hashtype" defined and if the hash length is not 8, 32, or 40
/// </param>
/// <returns>Hash info</returns>
public static HashInfoType ReadHashcheckFile(string hashCheckFilePath, HashTypeConstants assumedHashType = HashTypeConstants.Undefined)
{
var splitChar = new[] { '=' };
var hashInfo = new HashInfoType();
hashInfo.Clear();
using (var reader = new StreamReader(new FileStream(hashCheckFilePath, FileMode.Open, FileAccess.Read, FileShare.ReadWrite)))
{
while (!reader.EndOfStream)
{
var dataLine = reader.ReadLine();
if (string.IsNullOrWhiteSpace(dataLine) || dataLine.Trim().StartsWith("#") || !dataLine.Contains("="))
{
continue;
}
var dataColumns = dataLine.Trim().Split(splitChar, 2);
if (dataColumns.Length > 2)
{
continue;
}
switch (dataColumns[0].ToLower())
{
case "size":
long.TryParse(dataColumns[1], out hashInfo.FileSize);
break;
case "date":
case "modification_date_utc":
DateTime.TryParse(dataColumns[1], out hashInfo.FileDateUtc);
break;
case "hash":
hashInfo.HashValue = dataColumns[1];
break;
case "hashtype":
switch (dataColumns[1].ToLower())
{
case CRC32_HASH:
hashInfo.HashType = HashTypeConstants.CRC32;
break;
case MD5_HASH:
hashInfo.HashType = HashTypeConstants.MD5;
break;
case SHA1_HASH:
hashInfo.HashType = HashTypeConstants.SHA1;
break;
default:
hashInfo.HashType = HashTypeConstants.Undefined;
break;
}
break;
}
}
}
if (hashInfo.HashType != HashTypeConstants.Undefined)
{
return(hashInfo);
}
if (hashInfo.HashValue.Length == 8)
{
hashInfo.HashType = HashTypeConstants.CRC32;
}
else if (hashInfo.HashValue.Length == 32)
{
hashInfo.HashType = HashTypeConstants.MD5;
}
else if (hashInfo.HashValue.Length == 40)
{
hashInfo.HashType = HashTypeConstants.SHA1;
}
else
{
hashInfo.HashType = assumedHashType;
}
return(hashInfo);
}
/// <summary>
/// Creates a .hashcheck file for the specified file
/// The file will be created in the same directory as the data file, and will contain size, modification_date_utc, hash, and hashtype
/// </summary>
/// <param name="dataFilePath">File path to hash</param>
/// <param name="hashType">Hash type</param>
/// <param name="hashValue">Output: the computed file hash</param>
/// <param name="warningMessage">Output: warning message</param>
/// <returns>The full path to the .hashcheck file; empty string if a problem</returns>
/// <remarks></remarks>
public static string CreateHashcheckFileWithHash(
string dataFilePath,
HashTypeConstants hashType,
string hashValue,
out string warningMessage)
{
var fiDataFile = new FileInfo(dataFilePath);
if (!fiDataFile.Exists)
{
warningMessage = "Cannot create .hashcheck file; source file not found: " + fiDataFile.FullName;
return(string.Empty);
}
var hashCheckFilePath = fiDataFile.FullName + HASHCHECK_FILE_SUFFIX;
if (string.IsNullOrWhiteSpace(hashValue))
{
hashValue = string.Empty;
}
string hashTypeDescription;
switch (hashType)
{
case HashTypeConstants.Undefined:
hashTypeDescription = UNDEFINED_HASH;
break;
case HashTypeConstants.CRC32:
hashTypeDescription = CRC32_HASH;
break;
case HashTypeConstants.MD5:
hashTypeDescription = MD5_HASH;
break;
case HashTypeConstants.SHA1:
hashTypeDescription = SHA1_HASH;
break;
default:
throw new ArgumentOutOfRangeException(nameof(hashType), "Unknown hash type");
}
try
{
using (var swOutFile = new StreamWriter(new FileStream(hashCheckFilePath, FileMode.Create, FileAccess.Write, FileShare.Read)))
{
swOutFile.WriteLine("# Hashcheck file created " + DateTime.Now.ToString(DATE_TIME_FORMAT));
swOutFile.WriteLine("size=" + fiDataFile.Length);
swOutFile.WriteLine("modification_date_utc=" + fiDataFile.LastWriteTimeUtc.ToString(DATE_TIME_FORMAT));
swOutFile.WriteLine("hash=" + hashValue);
swOutFile.WriteLine("hashtype=" + hashTypeDescription);
}
warningMessage = string.Empty;
return(hashCheckFilePath);
}
catch (Exception ex)
{
// Treat this as a non-critical error
warningMessage = string.Format("Unable to create .hashcheck file {0}: {1}", hashCheckFilePath, ex.Message);
return(string.Empty);
}
}
