public IEnumerable <ContentFormat> Identify(IByteContainer container)
{
var toRead = (int)Math.Min(container.Length, 1024);
byte[] bytes = container.Read(0, toRead);
if (bytes.Length >= 4 && bytes[0] == 0 && bytes[1] == 0 && bytes[2] == 0xfe && bytes[3] == 0xff)
{
// UTF-32, big-endian
var decoder = new UTF32Encoding(true, false, false);
var chars = new char[2048];
int decoded = decoder.GetChars(bytes, 4, bytes.Length - 4, chars, 0);
if (decoded > (int)(((toRead - 4) / 4) * 0.9))
{
yield return(CreateTextFormat("utf-32/big-endian", decoder, bytes, (decoded * 4) + 4));
yield break;
}
}
else if (bytes.Length >= 4 && bytes[0] == 0 && bytes[1] == 0 && bytes[2] == 0xfe && bytes[3] == 0xff)
{
// UTF-32, little-endian
var decoder = new UTF32Encoding(false, false, false);
var chars = new char[2048];
int decoded = decoder.GetChars(bytes, 4, bytes.Length - 4, chars, 0);
if (decoded > (int)(((toRead - 4) / 4) * 0.9))
{
yield return(CreateTextFormat("utf-32/little-endian", decoder, bytes, (decoded * 4) + 4));
yield break;
}
}
else if (bytes.Length >= 2 && bytes[0] == 0xfe && bytes[1] == 0xff)
{
// UTF-16, big-endian
var decoder = new UnicodeEncoding(true, false, false);
var chars = new char[2048];
int decoded = decoder.GetChars(bytes, 2, bytes.Length - 2, chars, 0);
if (decoded > (int)(((toRead - 2) / 2) * 0.9))
{
yield return(CreateTextFormat("utf-16/big-endian", decoder, bytes, (decoded * 2) + 2));
yield break;
}
}
else if (bytes.Length >= 2 && bytes[0] == 0xff && bytes[1] == 0xfe)
{
// UTF-16, little-endian
var decoder = new UnicodeEncoding(false, false, false);
var chars = new char[2048];
int decoded = decoder.GetChars(bytes, 2, bytes.Length - 2, chars, 0);
if (decoded > (int)(((toRead - 2) / 2) * 0.9))
{
yield return(CreateTextFormat("utf-16/little-endian", decoder, bytes, (decoded * 2) + 2));
yield break;
}
}
else if (bytes.Length >= 3 && bytes[0] == 0xef && bytes[1] == 0xbb && bytes[2] == 0xbf)
{
// UTF-8
var decoder = new UTF8Encoding(false, false);
var chars = new char[2048];
int decoded = decoder.GetChars(bytes, 3, bytes.Length - 3, chars, 0);
if (decoded > (int)(((toRead - 3) / 2) * 0.8))
{
yield return(CreateTextFormat("utf-8", decoder, bytes, (decoded * 2) + 2));
yield break;
}
}
var encoders = new Dictionary <string, Encoding>
{
{ "utf-8", new UTF8Encoding(true, true) },
{ "cp1252", Encoding.GetEncoding("Windows-1252") },
{ "iso-8859-1", Encoding.GetEncoding("iso-8859-1") },
{ "utf-16/big-endian", new UnicodeEncoding(true, false, true) },
{ "utf-16/little-endian", new UnicodeEncoding(false, false, true) },
{ "utf-32/big-endian", new UTF32Encoding(true, false, true) },
{ "utf-32/little-endian", new UTF32Encoding(false, false, true) },
};
foreach (var encoder in encoders)
{
byte[] bytes2;
try
{
string s = encoder.Value.GetString(bytes, 0, bytes.Length);
bytes2 = encoder.Value.GetBytes(s.Substring(0, (int)(s.Length * 0.9)));
}
catch
{
continue;
}
if (bytes2.Length == 0)
{
continue;
}
if (bytes.Any(b => b == 0))
{
continue;
}
bool isMatch = true;
for (int index = 0; index < bytes2.Length; index++)
{
if (bytes[index] != bytes2[index])
{
isMatch = false;
break;
}
}
if (isMatch)
{
yield return(CreateTextFormat(encoder.Key, encoder.Value, bytes, bytes2.Length));
yield break;
}
}
}
