private string ComputeHash()
{
try
{
// Create SHA256 hash calculator
using var hashCalculator = SHA256.Create();
// Create a buffer to hold the file data being hashed
byte[] buffer = new byte[2 * HashWindowLength];
// Open file
using FileStream fileStream = MediaFileInfo.Open(FileMode.Open);
// Small files read entire file, big files read front and back
if (MediaFileInfo.Length <= buffer.Length)
{
// Read the entire file
fileStream.Seek(0, SeekOrigin.Begin);
if (fileStream.Read(buffer, 0, (int)MediaFileInfo.Length) != MediaFileInfo.Length)
{
Log.Logger.Error("Error reading from media file : {FileName}", MediaFileInfo.Name);
return(null);
}
}
else
{
// Read the beginning of the file
fileStream.Seek(0, SeekOrigin.Begin);
if (fileStream.Read(buffer, 0, HashWindowLength) != HashWindowLength)
{
Log.Logger.Error("Error reading from media file : {FileName}", MediaFileInfo.Name);
return(null);
}
// Read the end of the file
fileStream.Seek(-HashWindowLength, SeekOrigin.End);
if (fileStream.Read(buffer, HashWindowLength, HashWindowLength) != HashWindowLength)
{
Log.Logger.Error("Error reading from media file : {FileName}", MediaFileInfo.Name);
return(null);
}
}
// Close stream
fileStream.Close();
// Calculate the hash
byte[] hash = hashCalculator.ComputeHash(buffer);
// Convert to string
return(System.Convert.ToBase64String(hash));
}
catch (Exception e) when(Log.Logger.LogAndHandle(e, MethodBase.GetCurrentMethod()?.Name))
{
return(null);
}
}
