Crisis.Ionic.Zlib.ZlibBaseStream._ReadAndValidateGzipHeader C# (CSharp) Méthode

        private int _ReadAndValidateGzipHeader()
        {
            int totalBytesRead = 0;
            // read the header on the first read
            byte[] header = new byte[10];
            int n = _stream.Read(header, 0, header.Length);

            // workitem 8501: handle edge case (decompress empty stream)
            if (n == 0)
                return 0;

            if (n != 10)
                throw new ZlibException("Not a valid GZIP stream.");

            if (header[0] != 0x1F || header[1] != 0x8B || header[2] != 8)
                throw new ZlibException("Bad GZIP header.");

            Int32 timet = BitConverter.ToInt32(header, 4);
            _GzipMtime = GZipStream._unixEpoch.AddSeconds(timet);
            totalBytesRead += n;
            if ((header[3] & 0x04) == 0x04)
            {
                // read and discard extra field
                n = _stream.Read(header, 0, 2); // 2-byte length field
                totalBytesRead += n;

                Int16 extraLength = (Int16)(header[0] + header[1] * 256);
                byte[] extra = new byte[extraLength];
                n = _stream.Read(extra, 0, extra.Length);
                if (n != extraLength)
                    throw new ZlibException("Unexpected end-of-file reading GZIP header.");
                totalBytesRead += n;
            }
            if ((header[3] & 0x08) == 0x08)
                _GzipFileName = ReadZeroTerminatedString();
            if ((header[3] & 0x10) == 0x010)
                _GzipComment = ReadZeroTerminatedString();
            if ((header[3] & 0x02) == 0x02)
                Read(_buf1, 0, 1); // CRC16, ignore

            return totalBytesRead;
        }