/// <summary>
        /// Parses body from the specified stream
        /// </summary>
        /// <param name="owner">Owner MIME entity.</param>
        /// <param name="defaultContentType">Default content-type for this body.</param>
        /// <param name="stream">Stream from where to read body.</param>
        /// <returns>Returns parsed body.</returns>
        /// <exception cref="ArgumentNullException">Is raised when <b>stream</b>, <b>defaultContentType</b> or <b>stream</b> is null reference.</exception>
        /// <exception cref="ParseException">Is raised when any parsing errors.</exception>
        protected static new MIME_b Parse(MIME_Entity owner,MIME_h_ContentType defaultContentType,SmartStream stream)
        {
            if(owner == null){
                throw new ArgumentNullException("owner");
            }
            if(defaultContentType == null){
                throw new ArgumentNullException("defaultContentType");
            }
            if(stream == null){
                throw new ArgumentNullException("stream");
            }

            // We need to buffer all body data, otherwise we don't know if we have readed all data 
            // from stream.
            MemoryStream msBuffer = new MemoryStream();
            Net_Utils.StreamCopy(stream,msBuffer,32000);
            msBuffer.Position = 0;

            SmartStream parseStream = new SmartStream(msBuffer,true);

            MIME_b_MessageDeliveryStatus retVal = new MIME_b_MessageDeliveryStatus();
            //Pare per-message fields.
            retVal.m_pMessageFields.Parse(parseStream);

            // Parse per-recipient fields.
            while(parseStream.Position - parseStream.BytesInReadBuffer < parseStream.Length){
                MIME_h_Collection recipientFields = new MIME_h_Collection(new MIME_h_Provider());
                recipientFields.Parse(parseStream);
                retVal.m_pRecipientBlocks.Add(recipientFields);                
            }                     

            return retVal;
        }

        /// <summary>
        /// Parses body from the specified stream
        /// </summary>
        /// <param name="owner">Owner MIME entity.</param>
        /// <param name="defaultContentType">Default content-type for this body.</param>
        /// <param name="stream">Stream from where to read body.</param>
        /// <returns>Returns parsed body.</returns>
        /// <exception cref="ArgumentNullException">Is raised when <b>stream</b>, <b>defaultContentType</b> or <b>strean</b> is null reference.</exception>
        /// <exception cref="ParseException">Is raised when any parsing errors.</exception>
        protected static new MIME_b Parse(MIME_Entity owner,MIME_h_ContentType defaultContentType,SmartStream stream)
        {
            if(owner == null){
                throw new ArgumentNullException("owner");
            }
            if(defaultContentType == null){
                throw new ArgumentNullException("defaultContentType");
            }
            if(stream == null){
                throw new ArgumentNullException("stream");
            }

            string mediaType = null;
            try{
                mediaType = owner.ContentType.TypeWithSubtype;
            }
            catch{
                mediaType = "unparsable/unparsable";
            }

            MIME_b_Unknown retVal = new MIME_b_Unknown(mediaType);
            Net_Utils.StreamCopy(stream,retVal.EncodedStream,32000);

            return retVal;
        }

        /// <summary>
        /// Parses body from the specified stream
        /// </summary>
        /// <param name="owner">Owner MIME entity.</param>
        /// <param name="defaultContentType">Default content-type for this body.</param>
        /// <param name="stream">Stream from where to read body.</param>
        /// <returns>Returns parsed body.</returns>
        /// <exception cref="ArgumentNullException">Is raised when <b>stream</b>, <b>mediaType</b> or <b>stream</b> is null reference.</exception>
        /// <exception cref="ParseException">Is raised when any parsing errors.</exception>
        protected static new MIME_b Parse(MIME_Entity owner,MIME_h_ContentType defaultContentType,SmartStream stream)
        {
            if(owner == null){
                throw new ArgumentNullException("owner");
            }
            if(defaultContentType == null){
                throw new ArgumentNullException("defaultContentType");
            }
            if(stream == null){
                throw new ArgumentNullException("stream");
            }

            MIME_b_Text retVal = null;
            if(owner.ContentType != null){
                retVal = new MIME_b_Text(owner.ContentType.TypeWithSubtype);
            }
            else{
                retVal = new MIME_b_Text(defaultContentType.TypeWithSubtype);
            }

            Net_Utils.StreamCopy(stream,retVal.EncodedStream,32000);
            retVal.SetModified(false);

            return retVal;
        }

                /// <summary>
                /// Assigns data line info from rea line operation.
                /// </summary>
                /// <param name="op">Read line operation.</param>
                /// <exception cref="ArgumentNullException">Is raised when <b>op</b> is null reference.</exception>
                public void AssignFrom(SmartStream.ReadLineAsyncOP op)
                {
                    if(op == null){
                        throw new ArgumentNullException();
                    }

                    m_BytesInBuffer = op.BytesInBuffer;
                    Array.Copy(op.Buffer,m_pLineBuffer,op.BytesInBuffer);
                }

      internal bool Start(SmartStream stream)
      {   
          // TODO: Clear old data, if any.
          m_IsCompleted   = false;
          m_BytesInBuffer = 0;
          m_pException    = null;
 
          return DoLineReading();
      }

        /// <summary>
        /// Parses MIME entity body from specified stream.
        /// </summary>
        /// <param name="owner">Owner MIME entity.</param>
        /// <param name="stream">Stream from where to parse entity body.</param>
        /// <param name="defaultContentType">Default content type.</param>
        /// <returns>Returns parsed body.</returns>
        /// <exception cref="ArgumentNullException">Is raised when <b>owner</b>, <b>strean</b> or <b>defaultContentType</b> is null reference.</exception>
        /// <exception cref="ParseException">Is raised when header field parsing errors.</exception>
        public MIME_b Parse(MIME_Entity owner,SmartStream stream,MIME_h_ContentType defaultContentType)
        {
            if(owner == null){
                throw new ArgumentNullException("owner");
            }
            if(stream == null){
                throw new ArgumentNullException("stream");
            }
            if(defaultContentType == null){
                throw new ArgumentNullException("defaultContentType");
            }

            string mediaType = defaultContentType.TypeWithSubype;
            if(owner.ContentType != null){
                mediaType = owner.ContentType.TypeWithSubype;
            }

            Type bodyType = null;

            // We have exact body provider for specified mediaType.
            if(m_pBodyTypes.ContainsKey(mediaType)){
                bodyType = m_pBodyTypes[mediaType];
            }
            // Use default mediaType.
            else{
                // Registered list of mediaTypes are available: http://www.iana.org/assignments/media-types/.

                string mediaRootType = mediaType.Split('/')[0].ToLowerInvariant();
                if(mediaRootType == "application"){
                    bodyType = typeof(MIME_b_Application);
                }
                else if(mediaRootType == "audio"){
                    bodyType = typeof(MIME_b_Audio);
                }
                else if(mediaRootType == "image"){
                    bodyType = typeof(MIME_b_Image);
                }
                else if(mediaRootType == "message"){
                    bodyType = typeof(MIME_b_Message);
                }
                else if(mediaRootType == "multipart"){
                    bodyType = typeof(MIME_b_Multipart);
                }
                else if(mediaRootType == "text"){
                    bodyType = typeof(MIME_b_Text);
                }
                else if(mediaRootType == "video"){
                    bodyType = typeof(MIME_b_Video);
                }
                else{
                    throw new ParseException("Invalid media-type '" + mediaType + "'.");
                }
            }

            return (MIME_b)bodyType.GetMethod("Parse",System.Reflection.BindingFlags.Static | System.Reflection.BindingFlags.NonPublic | System.Reflection.BindingFlags.FlattenHierarchy).Invoke(null,new object[]{owner,mediaType,stream});
        }

        /// <summary>
        /// Default constructor.
        /// </summary>
        /// <param name="stream">Source stream.</param>
        /// <param name="access">Specifies stream access mode.</param>
        /// <exception cref="ArgumentNullException">Is raised when <b>stream</b> is null reference.</exception>
        public QuotedPrintableStream(SmartStream stream,FileAccess access)
        {
            if(stream == null){
                throw new ArgumentNullException("stream");
            }

            m_pStream    = stream;
            m_AccessMode = access;

            m_pDecodedBuffer = new byte[32000];
            m_pEncodedBuffer = new byte[78];
        }

        /// <summary>
        /// Parses body from the specified stream
        /// </summary>
        /// <param name="owner">Owner MIME entity.</param>
        /// <param name="defaultContentType">Default content-type for this body.</param>
        /// <param name="stream">Stream from where to read body.</param>
        /// <returns>Returns parsed body.</returns>
        /// <exception cref="ArgumentNullException">Is raised when <b>stream</b>, <b>defaultContentType</b> or <b>stream</b> is null reference.</exception>
        /// <exception cref="ParseException">Is raised when any parsing errors.</exception>
        protected static MIME_b Parse(MIME_Entity owner,MIME_h_ContentType defaultContentType,SmartStream stream)
        {
            if(owner == null){
                throw new ArgumentNullException("owner");
            }
            if(defaultContentType == null){
                throw new ArgumentNullException("defaultContentType");
            }
            if(stream == null){
                throw new ArgumentNullException("stream");
            }

            throw new NotImplementedException("Body provider class does not implement required Parse method.");
        }

        /// <summary>
        /// Parses body from the specified stream
        /// </summary>
        /// <param name="owner">Owner MIME entity.</param>
        /// <param name="defaultContentType">Default content-type for this body.</param>
        /// <param name="stream">Stream from where to read body.</param>
        /// <returns>Returns parsed body.</returns>
        /// <exception cref="ArgumentNullException">Is raised when <b>stream</b>, <b>defaultContentType</b> or <b>stream</b> is null reference.</exception>
        /// <exception cref="ParseException">Is raised when any parsing errors.</exception>
        protected static new MIME_b Parse(MIME_Entity owner,MIME_h_ContentType defaultContentType,SmartStream stream)
        {
            if(owner == null){
                throw new ArgumentNullException("owner");
            }
            if(defaultContentType == null){
                throw new ArgumentNullException("defaultContentType");
            }
            if(stream == null){
                throw new ArgumentNullException("stream");
            }

            MIME_b_MessageRfc822 retVal = new MIME_b_MessageRfc822();
            retVal.m_pMessage = Mail_Message.ParseFromStream(stream);

            return retVal;
        }

        /// <summary>
        /// Parses body from the specified stream
        /// </summary>
        /// <param name="owner">Owner MIME entity.</param>
        /// <param name="defaultContentType">Default content-type for this body.</param>
        /// <param name="stream">Stream from where to read body.</param>
        /// <returns>Returns parsed body.</returns>
        /// <exception cref="ArgumentNullException">Is raised when <b>stream</b>, <b>defaultContentType</b> or <b>strean</b> is null reference.</exception>
        /// <exception cref="ParseException">Is raised when any parsing errors.</exception>
        protected static new MIME_b Parse(MIME_Entity owner,MIME_h_ContentType defaultContentType,SmartStream stream)
        {
            if(owner == null){
                throw new ArgumentNullException("owner");
            }
            if(defaultContentType == null){
                throw new ArgumentNullException("defaultContentType");
            }
            if(stream == null){
                throw new ArgumentNullException("stream");
            }

            MIME_b_ApplicationPkcs7Mime retVal = new MIME_b_ApplicationPkcs7Mime();
            Net_Utils.StreamCopy(stream,retVal.EncodedStream,32000);

            return retVal;
        }

        /// <summary>
        /// Parses body from the specified stream
        /// </summary>
        /// <param name="owner">Owner MIME entity.</param>
        /// <param name="mediaType">MIME media type. For example: text/plain.</param>
        /// <param name="stream">Stream from where to read body.</param>
        /// <returns>Returns parsed body.</returns>
        /// <exception cref="ArgumentNullException">Is raised when <b>stream</b>, <b>mediaType</b> or <b>strean</b> is null reference.</exception>
        /// <exception cref="ParseException">Is raised when any parsing errors.</exception>
        protected static new MIME_b Parse(MIME_Entity owner,string mediaType,SmartStream stream)
        {
            if(owner == null){
                throw new ArgumentNullException("owner");
            }
            if(mediaType == null){
                throw new ArgumentNullException("mediaType");
            }
            if(stream == null){
                throw new ArgumentNullException("stream");
            }

            MIME_b_Audio retVal = new MIME_b_Audio(mediaType);

            Net_Utils.StreamCopy(stream,retVal.EncodedStream,32000);

            return retVal;
        }

        /// <summary>
        /// Parses body from the specified stream
        /// </summary>
        /// <param name="owner">Owner MIME entity.</param>
        /// <param name="mediaType">MIME media type. For example: text/plain.</param>
        /// <param name="stream">Stream from where to read body.</param>
        /// <returns>Returns parsed body.</returns>
        /// <exception cref="ArgumentNullException">Is raised when <b>stream</b>, <b>mediaType</b> or <b>stream</b> is null reference.</exception>
        /// <exception cref="ParseException">Is raised when any parsing errors.</exception>
        protected static new MIME_b Parse(MIME_Entity owner,string mediaType,SmartStream stream)
        {
            if(owner == null){
                throw new ArgumentNullException("owner");
            }
            if(mediaType == null){
                throw new ArgumentNullException("mediaType");
            }
            if(stream == null){
                throw new ArgumentNullException("stream");
            }
            if(owner.ContentType == null || owner.ContentType.Param_Boundary == null){
                throw new ParseException("Multipart entity has not required 'boundary' paramter.");
            }

            MIME_b_MultipartRelated retVal = new MIME_b_MultipartRelated(owner.ContentType);
            ParseInternal(owner,mediaType,stream,retVal);

            return retVal;
        }

        /// <summary>
        /// Parses body from the specified stream
        /// </summary>
        /// <param name="owner">Owner MIME entity.</param>
        /// <param name="defaultContentType">Default content-type for this body.</param>
        /// <param name="stream">Stream from where to read body.</param>
        /// <returns>Returns parsed body.</returns>
        /// <exception cref="ArgumentNullException">Is raised when <b>stream</b>, <b>defaultContentType</b> or <b>stream</b> is null reference.</exception>
        /// <exception cref="ParseException">Is raised when any parsing errors.</exception>
        protected static new MIME_b Parse(MIME_Entity owner,MIME_h_ContentType defaultContentType,SmartStream stream)
        {
            if(owner == null){
                throw new ArgumentNullException("owner");
            }
            if(defaultContentType == null){
                throw new ArgumentNullException("defaultContentType");
            }
            if(stream == null){
                throw new ArgumentNullException("stream");
            }
            if(owner.ContentType == null || owner.ContentType.Param_Boundary == null){
                throw new ParseException("Multipart entity has not required 'boundary' paramter.");
            }
            
            MIME_b_MultipartParallel retVal = new MIME_b_MultipartParallel(owner.ContentType);
            ParseInternal(owner,owner.ContentType.TypeWithSubtype,stream,retVal);

            return retVal;
        }

        /// <summary>
        /// Parses body from the specified stream
        /// </summary>
        /// <param name="owner">Owner MIME entity.</param>
        /// <param name="defaultContentType">Default content-type for this body.</param>
        /// <param name="stream">Stream from where to read body.</param>
        /// <returns>Returns parsed body.</returns>
        /// <exception cref="ArgumentNullException">Is raised when <b>stream</b>, <b>defaultContentType</b> or <b>strean</b> is null reference.</exception>
        /// <exception cref="ParseException">Is raised when any parsing errors.</exception>
        protected static new MIME_b Parse(MIME_Entity owner,MIME_h_ContentType defaultContentType,SmartStream stream)
        {
            if(owner == null){
                throw new ArgumentNullException("owner");
            }
            if(defaultContentType == null){
                throw new ArgumentNullException("defaultContentType");
            }
            if(stream == null){
                throw new ArgumentNullException("stream");
            }

            MIME_b_Application retVal = null;
            if(owner.ContentType != null){
                retVal = new MIME_b_Application(owner.ContentType.TypeWithSubtype);
            }
            else{
                retVal = new MIME_b_Application(defaultContentType.TypeWithSubtype);
            }

            Net_Utils.StreamCopy(stream,retVal.EncodedStream,stream.LineBufferSize);

            return retVal;
        }

        /// <summary>
        /// Completes DATA command.
        /// </summary>
        /// <param name="startTime">Time DATA command started.</param>
        /// <param name="op">Read period-terminated opeartion.</param>
        private void DATA_End(DateTime startTime,SmartStream.ReadPeriodTerminatedAsyncOP op)
        {
            try{
                if(op.Error != null){
                    if(op.Error is LineSizeExceededException){
                        WriteLine("500 Line too long.");
                    }
                    else if(op.Error is DataSizeExceededException){
                        WriteLine("552 Too much mail data.");
                    }
                    else{
                        OnError(op.Error);
                    }

                    OnMessageStoringCanceled();
                }
                else{
                    SMTP_Reply reply = new SMTP_Reply(250,"DATA completed in " + (DateTime.Now - startTime).TotalSeconds.ToString("f2") + " seconds.");

                    reply = OnMessageStoringCompleted(reply);

                    WriteLine(reply.ToString());
                }
            }
            catch(Exception x){
                OnError(x);                
            }

            Reset();
            BeginReadCmd();
        }

            /// <summary>
            /// Is called when read line has completed.
            /// </summary>
            /// <param name="op">Asynchronous operation.</param>
            /// <returns>Returns true if multiline response has more response lines.</returns>
            /// <exception cref="ArgumentNullException">Is raised when <b>op</b> is null reference.</exception>
            private bool ReadLineCompleted(SmartStream.ReadLineAsyncOP op)
            {
                if(op == null){
                    throw new ArgumentNullException("op");
                }

                try{
                    // Line reading failed, we are done.
                    if(op.Error != null){
                        m_pException = op.Error;
                    }
                    // Line reading succeeded.
                    else{
                        // Log.
                        m_pSmtpClient.LogAddRead(op.BytesInBuffer,op.LineUtf8);

                        SMTP_t_ReplyLine replyLine = SMTP_t_ReplyLine.Parse(op.LineUtf8);
                        m_pReplyLines.Add(replyLine);

                        return !replyLine.IsLastLine;
                    }                    
                }
                catch(Exception x){
                    m_pException = x;
                }

                return false;
            }

            /// <summary>
            /// Is called when DATA command message sending has completed.
            /// </summary>
            /// <param name="op">Asynchronous operation.</param>
            /// <exception cref="ArgumentNullException">Is raised when <b>op</b> is null reference.</exception>
            private void DataMsgSendingCompleted(SmartStream.WritePeriodTerminatedAsyncOP op)
            {
                if(op == null){
                    throw new ArgumentNullException("op");
                }

                try{
                    if(op.Error != null){
                        m_pException = op.Error;
                        m_pSmtpClient.LogAddException("Exception: " + m_pException.Message,m_pException);
                        SetState(AsyncOP_State.Completed);
                    }
                    else{
                        // Log
                        m_pSmtpClient.LogAddWrite(op.BytesWritten,"Sent message " + op.BytesWritten + " bytes.");
                                                                       
                        // Read DATA command final response.
                        ReadResponseAsyncOP readResponseOP = new ReadResponseAsyncOP();
                        readResponseOP.CompletedAsync += delegate(object s,EventArgs<ReadResponseAsyncOP> e){
                            DataReadFinalResponseCompleted(readResponseOP);
                        };
                        if(!m_pSmtpClient.ReadResponseAsync(readResponseOP)){
                            DataReadFinalResponseCompleted(readResponseOP);
                        }
                    }
                }
                catch(Exception x){
                    m_pException = x;
                    m_pSmtpClient.LogAddException("Exception: " + m_pException.Message,m_pException);
                    SetState(AsyncOP_State.Completed);
                }

                op.Dispose();
            }

		/// <summary>
		/// Parses header fields from stream. Stream position stays where header reading ends.
		/// </summary>
		/// <param name="stream">Stream from where to parse.</param>
		public void Parse(SmartStream stream)
		{			
			/* Rfc 2822 2.2 Header Fields
				Header fields are lines composed of a field name, followed by a colon
				(":"), followed by a field body, and terminated by CRLF.  A field
				name MUST be composed of printable US-ASCII characters (i.e.,
				characters that have values between 33 and 126, inclusive), except
				colon.  A field body may be composed of any US-ASCII characters,
				except for CR and LF.  However, a field body may contain CRLF when
				used in header "folding" and  "unfolding" as described in section
				2.2.3.  All field bodies MUST conform to the syntax described in
				sections 3 and 4 of this standard. 
				
			   Rfc 2822 2.2.3 Long Header Fields
				The process of moving from this folded multiple-line representation
				of a header field to its single line representation is called
				"unfolding". Unfolding is accomplished by simply removing any CRLF
				that is immediately followed by WSP.  Each header field should be
				treated in its unfolded form for further syntactic and semantic
				evaluation.
				
				Example:
					Subject: aaaaa<CRLF>
					<TAB or SP>aaaaa<CRLF>
			*/

			m_pHeaderFields.Clear();

            SmartStream.ReadLineAsyncOP args = new SmartStream.ReadLineAsyncOP(new byte[32000],SizeExceededAction.JunkAndThrowException);
            stream.ReadLine(args,false);
            if(args.Error != null){
                throw args.Error;
            }
            string line = args.LineUtf8;

			while(line != null){
				// End of header reached
				if(line == ""){
					break;
				}

				// Store current header line and read next. We need to read 1 header line to ahead,
				// because of multiline header fields.
				string headerField = line; 
				stream.ReadLine(args,false);
                if(args.Error != null){
                    throw args.Error;
                }
                line = args.LineUtf8;

				// See if header field is multiline. See comment above.				
				while(line != null && (line.StartsWith("\t") || line.StartsWith(" "))){
					headerField += line;
					stream.ReadLine(args,false);
                    if(args.Error != null){
                        throw args.Error;
                    }
                    line = args.LineUtf8;
				}

				string[] name_value = headerField.Split(new char[]{':'},2);
				// There must be header field name and value, otherwise invalid header field
				if(name_value.Length == 2){
					Add(name_value[0] + ":",name_value[1].Trim());
				}
			}
		}

        /// <summary>
        /// Internal body parsing.
        /// </summary>
        /// <param name="owner">Owner MIME entity.</param>
        /// <param name="mediaType">MIME media type. For example: text/plain.</param>
        /// <param name="stream">Stream from where to read body.</param>
        /// <param name="body">Multipart body instance.</param>
        /// <exception cref="ArgumentNullException">Is raised when <b>stream</b>, <b>mediaType</b>, <b>stream</b> or <b>body</b> is null reference.</exception>
        /// <exception cref="ParseException">Is raised when any parsing errors.</exception>
        protected static void ParseInternal(MIME_Entity owner,string mediaType,SmartStream stream,MIME_b_Multipart body)
        {
            if(owner == null){
                throw new ArgumentNullException("owner");
            }
            if(mediaType == null){
                throw new ArgumentNullException("mediaType");
            }
            if(stream == null){
                throw new ArgumentNullException("stream");
            }
            if(owner.ContentType == null || owner.ContentType.Param_Boundary == null){
                throw new ParseException("Multipart entity has not required 'boundary' parameter.");
            }
            if(body == null){
                throw new ArgumentNullException("body");
            }

            _MultipartReader multipartReader = new _MultipartReader(stream,owner.ContentType.Param_Boundary);       
            while(multipartReader.Next()){
                MIME_Entity entity = new MIME_Entity();
                entity.Parse(new SmartStream(multipartReader,false),Encoding.UTF8,body.DefaultBodyPartContentType);
                body.m_pBodyParts.Add(entity);
                entity.SetParent(owner);
            }

            body.m_TextPreamble = multipartReader.TextPreamble;
            body.m_TextEpilogue = multipartReader.TextEpilogue;

            body.BodyParts.SetModified(false);
        }

            /// <summary>
            /// Default constructor.
            /// </summary>
            /// <param name="stream">Stream from where to read body part.</param>
            /// <param name="boundary">Boundry ID what separates body parts.</param>
            /// <exception cref="ArgumentNullException">Is raised when <b>stream</b> or <b>boundary</b> is null reference.</exception>
            public _MultipartReader(SmartStream stream,string boundary)
            {
                if(stream == null){
                    throw new ArgumentNullException("stream");
                }
                if(boundary == null){
                    throw new ArgumentNullException("boundary");
                }

                m_pStream  = stream;
                m_Boundary = boundary;

                m_pReadLineOP   = new SmartStream.ReadLineAsyncOP(new byte[stream.LineBufferSize],SizeExceededAction.ThrowException);
                m_pTextPreamble = new StringBuilder();
                m_pTextEpilogue = new StringBuilder();
            }