MimeBasePart.cs source code in C# .NET

                        Code:
                         / 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / fx / src / Net / System / Net / Mail / MimeBasePart.cs / 1305376 / MimeBasePart.cs
                        
                        
                            using System; 
using System.Collections.Specialized;
using System.IO;
using System.Text;
using System.Net.Mail; 

namespace System.Net.Mime 
{ 

    internal class MimeBasePart 
    {
        protected ContentType contentType;
        protected ContentDisposition contentDisposition;
        HeaderCollection headers; 
        internal const string defaultCharSet = "utf-8";//"iso-8859-1";
 
 
        internal MimeBasePart()
        { 
        }


        internal static bool ShouldUseBase64Encoding(Encoding encoding){ 
            if (encoding == Encoding.Unicode || encoding == Encoding.UTF8 || encoding == Encoding.UTF32  || encoding == Encoding.BigEndianUnicode) {
                return true; 
            } 
            return false;
        } 

        //use when the length of the header is not known or if there is no header
        internal static string EncodeHeaderValue(string value, Encoding encoding, bool base64Encoding){
            return MimeBasePart.EncodeHeaderValue(value, encoding, base64Encoding, 0); 
        }
 
        //used when the length of the header name itself is known (i.e. Subject : ) 
        internal static string EncodeHeaderValue(string value, Encoding encoding, bool base64Encoding, int headerLength) {
            StringBuilder newString = new StringBuilder(); 

            //no need to encode if it's pure ascii
            if (IsAscii(value, false)) {
                return value; 
            }
 
            if (encoding == null) { 
                encoding = Encoding.GetEncoding(MimeBasePart.defaultCharSet);
            } 

            EncodedStreamFactory factory = new EncodedStreamFactory();
            IEncodableStream stream = factory.GetEncoderForHeader(encoding, base64Encoding, headerLength);
 
            byte[] buffer = encoding.GetBytes(value);
            stream.EncodeBytes(buffer, 0, buffer.Length); 
            return stream.GetEncodedString(); 
        }
 
        internal static string DecodeHeaderValue(string value) {
            if(value == null || value.Length == 0){
                return String.Empty;
            } 

            string newValue = String.Empty; 
 
            //split strings, they may be folded.  If they are, decode one at a time and append the results
            string[] substringsToDecode = value.Split(new char[] { '\r', '\n', ' ' }, StringSplitOptions.RemoveEmptyEntries); 

            foreach (string foldedSubString in substringsToDecode) {
                //an encoded string has as specific format in that it must start and end with an
                //'=' char and contains five parts, separated by '?' chars. 
                //the first and last part are therefore '=', the second part is the byte encoding (B or Q)
                //the third is the unicode encoding type, and the fourth is encoded message itself.  '?' is not valid inside of 
                //an encoded string other than as a separator for these five parts. 
                //If this check fails, the string is either not encoded or cannot be decoded by this method
                string[] subStrings = foldedSubString.Split('?'); 
                if ((subStrings.Length != 5 || subStrings[0] != "=" || subStrings[4] != "=")) {
                    return value;
                }
 
                string charSet = subStrings[1];
                bool base64Encoding = (subStrings[2] == "B"); 
                byte[] buffer = ASCIIEncoding.ASCII.GetBytes(subStrings[3]); 
                int newLength;
 
                EncodedStreamFactory encoderFactory = new EncodedStreamFactory();
                IEncodableStream s = encoderFactory.GetEncoderForHeader(Encoding.GetEncoding(charSet), base64Encoding, 0);

                newLength = s.DecodeBytes(buffer, 0, buffer.Length); 

                Encoding encoding = Encoding.GetEncoding(charSet); 
                newValue += encoding.GetString(buffer, 0, newLength); 
            }
            return newValue; 
        }

        internal static Encoding DecodeEncoding(string value) {
            if(value == null || value.Length == 0){ 
                return null;
            } 
 
            string[] subStrings = value.Split('?');
            if ((subStrings.Length != 5 || subStrings[0] != "=" || subStrings[4] != "=")) { 
                return null;
            }
            string charSet = subStrings[1];
            return Encoding.GetEncoding(charSet); 
        }
 
 

        internal static bool IsAscii(string value, bool permitCROrLF) { 
            if (value == null)
                throw new ArgumentNullException("value");

            foreach (char c in value) { 
                if ((int)c > 0x7f) {
                    return false; 
                } 
                if (!permitCROrLF && (c=='\r' || c=='\n')) {
                    return false; 
                }
            }
            return true;
        } 

        internal static bool IsAnsi(string value, bool permitCROrLF) { 
            if (value == null) 
                throw new ArgumentNullException("value");
 
            foreach (char c in value) {
                if ((int)c > 0xff) {
                    return false;
                } 
                if (!permitCROrLF && (c=='\r' || c=='\n')) {
                    return false; 
                } 
            }
            return true; 
        }

        internal string ContentID {
            get { 
                return Headers[MailHeaderInfo.GetString(MailHeaderID.ContentID)];
            } 
            set { 
                if (string.IsNullOrEmpty(value))
                { 
                    Headers.Remove(MailHeaderInfo.GetString(MailHeaderID.ContentID));
                }
                else
                { 
                    Headers[MailHeaderInfo.GetString(MailHeaderID.ContentID)] = value;
                } 
            } 
        }
 
        internal string ContentLocation
        {
            get
            { 
                return Headers[MailHeaderInfo.GetString(MailHeaderID.ContentLocation)];
            } 
            set 
            {
                if (string.IsNullOrEmpty(value)) 
                {
                    Headers.Remove(MailHeaderInfo.GetString(MailHeaderID.ContentLocation));
                }
                else 
                {
                    Headers[MailHeaderInfo.GetString(MailHeaderID.ContentLocation)] = value; 
                } 
            }
        } 

        internal NameValueCollection Headers
        {
            get { 
                //persist existing info before returning
                if (headers == null) 
                    headers = new HeaderCollection(); 

                if (contentType == null){ 
                    contentType = new ContentType();
                }
                contentType.PersistIfNeeded(headers,false);
 
                if (contentDisposition != null)
                    contentDisposition.PersistIfNeeded(headers,false); 
                return headers; 
            }
        } 

        internal ContentType ContentType{
            get{
                if (contentType == null){ 
                    contentType = new ContentType();
                } 
                return contentType; 
            }
            set { 
                if (value == null)
                    throw new ArgumentNullException("value");

                contentType = value; 
                contentType.PersistIfNeeded((HeaderCollection)Headers,true);
            } 
        } 

 
        internal virtual void Send(BaseWriter writer) { throw new NotImplementedException(); }
        internal virtual IAsyncResult BeginSend(BaseWriter writer, AsyncCallback callback, object state) { throw new NotImplementedException(); }

        internal void EndSend(IAsyncResult asyncResult) { 

            if (asyncResult == null) { 
                throw new ArgumentNullException("asyncResult"); 
            }
 
            LazyAsyncResult castedAsyncResult = asyncResult as MimePartAsyncResult;

            if (castedAsyncResult == null || castedAsyncResult.AsyncObject != this) {
                throw new ArgumentException(SR.GetString(SR.net_io_invalidasyncresult), "asyncResult"); 
            }
 
            if (castedAsyncResult.EndCalled) { 
                throw new InvalidOperationException(SR.GetString(SR.net_io_invalidendcall, "EndSend"));
            } 

            castedAsyncResult.InternalWaitForCompletion();
            castedAsyncResult.EndCalled = true;
            if (castedAsyncResult.Result is Exception) { 
                throw (Exception)castedAsyncResult.Result;
            } 
        } 

        internal class MimePartAsyncResult: LazyAsyncResult { 
            internal MimePartAsyncResult(MimeBasePart part, object state, AsyncCallback callback):base(part,state,callback) {
            }
        }
    } 
}
 

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
// Copyright (c) Microsoft Corporation. All rights reserved.
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MimeBasePart.cs source code in C# .NET

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