improvement on parsing the attachment

[Wilson Chan]

I have found there was some thing to be improved with the attachment class:

        private void parseHeader(StringReader sr,string temp)
        {
            string []array=Utility.getHeadersValue(temp);
            string []values=array[1].Split(";".ToCharArray());

            switch(array[0].ToUpper())
            {               
                case "CONTENT-TYPE":
                    //_contentType=Utility.splitOnSemiColon(array[1])[0].Trim();
                    //if(array[1].ToLower().IndexOf("charset".ToLower())!=-1)
                    //    _contentCharset=Utility.splitOnSemiColon(array[1])[1].Trim();
                    //break;
                    if(values.Length>0)
                        _contentType=values[0].Trim();
                    if(values.Length>1)
                    {
                        _contentCharset=Utility.GetQuotedValue(values[1],"=","charset");
                    }
                    if(values.Length>2)
                    {
                        _contentFormat=Utility.GetQuotedValue(values[2],"=","format");
                    }
                    break;
                case "CONTENT-TRANSFER-ENCODING":
                    _contentTransferEncoding=Utility.splitOnSemiColon(array[1])[0].Trim();
                    break;
                case "CONTENT-DESCRIPTION":
                    _contentDescription=Utility.deCode(Utility.splitOnSemiColon(array[1])[0].Trim());
                    break;
                case "CONTENT-DISPOSITION":
                    //_contentDisposition=Utility.splitOnSemiColon(array[1])[0].Trim();
//                    _contentFileName=Utility.splitOnSemiColon(array[1])[1].Trim();
//                    _contentFileName=_contentFileName.Substring(10,_contentFileName.Length-11);
                    if(values.Length>0)
                        _contentDisposition=values[0].Trim();
                   
                    _contentFileName=values[1];
                   
                    if(_contentFileName=="")
                        _contentFileName=sr.ReadLine();

                    _contentFileName=Utility.GetQuotedValue(_contentFileName,"=","filename");
                    _contentFileName=Utility.deCode(_contentFileName);
                    break;
                case "Content-Id":
                    _contentID=Utility.splitOnSemiColon(array[1])[0].Trim();
                    break;
            }
        }

[Wilson Chan]

        public bool IsEncoding(string encoding)
        {
            return _contentTransferEncoding.ToLower().IndexOf(encoding.ToLower())!=-1;
        }

        /// <summary>
        /// Decode the attachment to text
        /// </summary>
        /// <returns>Decoded attachment text</returns>
        public string DecodeAttachmentAsText()
        {
            string decodedAttachment=null;

            if(_contentType=="message/rfc822")
                decodedAttachment=Utility.deCode(_rawAttachment);
            else if(_contentTransferEncoding!=null)
            {
                decodedAttachment=_rawAttachment;

                if(!IsEncoding("7bit"))
                {
                    if(IsEncoding("8bit")&&_contentCharset!=null&_contentCharset!="")
                        decodedAttachment=Utility.Change(decodedAttachment,_contentCharset);

                    decodedAttachment=Utility.deCodeB64s(Utility.RemoveNonB64(decodedAttachment));
                    //decodedAttachment=Encoding.Default.GetString(Convert.FromBase64String(Utility.RemoveNonB64(decodedAttachment)));
                }
            }
            else if(_contentCharset!=null)
                decodedAttachment=Utility.Change(_rawAttachment,_contentCharset);//Encoding.Default.GetString(Encoding.GetEncoding(_contentCharset).GetBytes(_rawAttachment));
            else
                decodedAttachment=_rawAttachment;

            return decodedAttachment;
        }

        public Message DecodeAsMessage()
        {
            return new Message(_rawAttachment,false);
        }

        /// <summary>
        /// Decode the attachment to bytes
        /// </summary>
        /// <returns>Decoded attachment bytes</returns>
        public byte[] DecodedAttachmentAsBytes()
        {
            if(_rawAttachment==null)
                return null;
            if(_contentFileName!="")
                //return Convert.FromBase64String(Utility.RemoveNonB64(_rawAttachment));
                //return Encoding.Default.GetBytes(DecodeAttachment());
            {
                byte []decodedBytes=null;

                if(_contentType=="message/rfc822")
                    decodedBytes=Encoding.Default.GetBytes(Utility.deCode(_rawAttachment));
                else if(_contentTransferEncoding!=null)
                {
                    if(!IsEncoding("7bit"))
                    {
                        string content=_rawAttachment;
                        if(IsEncoding("8bit")&&_contentCharset!=null&_contentCharset!="")
                            content=Utility.Change(content,_contentCharset);

                        decodedBytes=Convert.FromBase64String(Utility.RemoveNonB64(content));
                    }
                }
                else if(_contentCharset!=null)
                    decodedBytes=Encoding.Default.GetBytes(Utility.Change(_rawAttachment,_contentCharset));//Encoding.Default.GetString(Encoding.GetEncoding(_contentCharset).GetBytes(_rawAttachment));
                else
                    decodedBytes=Encoding.Default.GetBytes(_rawAttachment);

                return decodedBytes;
            }
            else
            {
                return null;
            }
        }

[Wilson Chan]

        public static string GetQuotedValue(string text, string splitter, string tag)
        {
            if(text==null)
                throw new ArgumentNullException("text","Argument was null");

            string []array=new String[2]{"",""};
            int indexOfSplitter=text.IndexOf(splitter);           

            try
            {
                array[0]=text.Substring(0,indexOfSplitter).Trim();
                array[1]=text.Substring(indexOfSplitter+1).Trim();
                int pos=array[1].IndexOf("\&quot;");
                if(pos!=-1)
                {
                    int pos2=array[1].IndexOf("\&quot;",pos+1);
                    array[1]=array[1].Substring(pos+1,pos2-pos-1);
                }
            }
            catch(Exception){}

            //return array;
            if(array[0].ToLower()==tag.ToLower())
                return array[1].Trim();
            else
                return null;
        }