System.Xml.XmlInputStream.Initialize C# (CSharp) Méthode

		private void Initialize (Stream stream)
		{
			buffer = new byte [64];
			this.stream = stream;
			enc = StrictUTF8; // Default to UTF8 if we can't guess it
			bufLength = stream.Read (buffer, 0, buffer.Length);
			if (bufLength == -1 || bufLength == 0) {
				return;
			}

			int c = ReadByteSpecial ();
			switch (c) {
			case 0xFF:
				c = ReadByteSpecial ();
				if (c == 0xFE) {
					// BOM-ed little endian utf-16
					enc = Encoding.Unicode;
				} else {
					// It doesn't start from "<?xml" then its encoding is utf-8
					bufPos = 0;
				}
				break;
			case 0xFE:
				c = ReadByteSpecial ();
				if (c == 0xFF) {
					// BOM-ed big endian utf-16
					enc = Encoding.BigEndianUnicode;
					return;
				} else {
					// It doesn't start from "<?xml" then its encoding is utf-8
					bufPos = 0;
				}
				break;
			case 0xEF:
				c = ReadByteSpecial ();
				if (c == 0xBB) {
					c = ReadByteSpecial ();
					if (c != 0xBF) {
						bufPos = 0;
					}
				} else {
					buffer [--bufPos] = 0xEF;
				}
				break;
			case '<':
				// try to get encoding name from XMLDecl.
				if (bufLength >= 5 && GetStringFromBytes (buffer, 1, 4) == "?xml") {
					bufPos += 4;
					c = SkipWhitespace ();

					// version. It is optional here.
					if (c == 'v') {
						while (c >= 0) {
							c = ReadByteSpecial ();
							if (c == '0') { // 0 of 1.0
								ReadByteSpecial ();
								break;
							}
						}
						c = SkipWhitespace ();
					}

					if (c == 'e') {
						int remaining = bufLength - bufPos;
						if (remaining >= 7 && GetStringFromBytes (buffer, bufPos, 7) == "ncoding") {
							bufPos += 7;
							c = SkipWhitespace();
							if (c != '=')
								throw encodingException;
							c = SkipWhitespace ();
							int quoteChar = c;
							StringBuilder sb = new StringBuilder ();
							while (true) {
								c = ReadByteSpecial ();
								if (c == quoteChar)
									break;
								else if (c < 0)
									throw encodingException;

								sb.Append ((char) c);
							}
							string encodingName = sb.ToString ();
							if (!XmlChar.IsValidIANAEncoding (encodingName))
								throw encodingException;
							enc = Encoding.GetEncoding (encodingName);
						}
					}
				}
#if TARGET_JVM
				else {
					if (bufLength >= 10 && Encoding.Unicode.GetString (buffer, 2, 8) == "?xml")
						enc = Encoding.Unicode;
				}
#endif
				bufPos = 0;
				break;
			default:
				bufPos = 0;
				break;
			}
		}