internal static Encoding GetFileEncoding(String fileName, out bool withBOM)
{
Encoding result = null;
FileInfo fileInfo = new FileInfo(fileName);
FileStream fileStream = null;
withBOM = true;
try
{
fileStream = fileInfo.OpenRead();
Encoding[] unicodeEncodings = { Encoding.BigEndianUnicode, Encoding.UTF32, new UTF8Encoding(true), Encoding.Unicode }; //new UTF8Encoding(false)
for (int i = 0; result == null && i < unicodeEncodings.Length; i++)
{
fileStream.Position = 0;
byte[] preamble = unicodeEncodings[i].GetPreamble();
bool preamblesAreEqual = true;
for (int j = 0; preamblesAreEqual && j < preamble.Length; j++)
{
preamblesAreEqual = (preamble[j] == fileStream.ReadByte());
}
if (!preamblesAreEqual)
{
continue;
}
result = unicodeEncodings[i];
}
if (result == null) //new UTF8Encoding(false) o Encoding.Default?
{
byte[] byteArray = new byte[Convert.ToInt32(fileStream.Length)];
fileStream.Read(byteArray, 0, Convert.ToInt32(fileStream.Length));
String sANSI = Encoding.Default.GetString(byteArray);
String sUTF8 = new UTF8Encoding(false).GetString(byteArray);
if (sANSI == sUTF8) //If they are equal let default value decide if it is UTF-8 without BOM, otherwise ANSI
{
if (GetDefaultEncoding() == new UTF8Encoding(false))
{
withBOM = false;
result = new UTF8Encoding(false);
}
else
{
result = Encoding.Default;
}
}
else //Otherwise I try to find en error character into file content
{
//foreach (char c in s)
//{
// if (c == 65533)
// {
// result = Encoding.Default;
// break;
// }
//}
if (sUTF8.Any(c => c == 65533))
{
result = Encoding.Default;
}
if (result == null)
{
withBOM = false;
result = new UTF8Encoding(false);
}
}
}
}
catch (IOException)
{
}
finally
{
if (fileStream != null)
{
fileStream.Close();
}
}
return(result ?? (Encoding.Default));
}