Recurity.Swf.BaseFile.ReadHeader C# (CSharp) Method

        protected void ReadHeader(Stream input)
        {
            BinaryReader br = new BinaryReader(input);

            if (!input.CanSeek)
            {
                Exception e = new ArgumentException("input stream can not seek");
                Log.Error(this, e);
                throw e;
            }

            input.Seek(0, SeekOrigin.Begin);

            byte[] sigbytes = br.ReadBytes(3);

            try
            {
                Signature = System.Text.ASCIIEncoding.ASCII.GetString(sigbytes);
                Version = br.ReadByte();
                Length = br.ReadUInt32();
            }
            catch (EndOfStreamException e)
            {
                Log.Error(this, e.Message);
                throw e;
            }

            // Checking the signature
            if (Signature.Equals("FWS", StringComparison.InvariantCulture))
            {
                Compressed = false;
            }
            else if (Signature.Equals("CWS", StringComparison.InvariantCulture))
            {
                Compressed = true;
            }
            else
            {
                Exception e = new SwfFormatException("Invalid Signature: '" + Signature + "'");
                Log.Error(this, e);
                throw e;
            }

            // Checking the version
            if ((Version > VersionMaximum) || (Version < VersionMinimum))
            {
                Exception e = new SwfFormatException("Invalid / unknown version " + Version.ToString());
                Log.Error(this, e);
                throw e;
            }
            if (Compressed && (Version < 6))
            {
                Log.Warn(this, "Compression is indicated, but version is " + Version.ToString() + " (must at least be 6)");
            }
        }