/// <summary>
/// Encodes specified text if it contains 8-bit chars, otherwise text won't be encoded.
/// </summary>
/// <param name="encoding">Encoding to use to encode text.</param>
/// <param name="charset">Charset to use for encoding. If not sure UTF-8 is strongly recommended.</param>
/// <param name="text">Text to encode.</param>
/// <returns>Returns encoded text.</returns>
/// <exception cref="ArgumentNullException">Is raised when <b>charset</b> or <b>text</b> is null reference.</exception>
public static string EncodeS(MIME_EncodedWordEncoding encoding, Encoding charset, string text)
{
if (charset == null)
{
throw new ArgumentNullException("charset");
}
if (text == null)
{
throw new ArgumentNullException("text");
}
/* RFC 2047 2.
* encoded-word = "=?" charset "?" encoding "?" encoded-text "?="
*
* An 'encoded-word' may not be more than 75 characters long, including
* 'charset', 'encoding', 'encoded-text', and delimiters. If it is
* desirable to encode more text than will fit in an 'encoded-word' of
* 75 characters, multiple 'encoded-word's (separated by CRLF SPACE) may
* be used.
*
* RFC 2231 (updates syntax)
* encoded-word := "=?" charset ["*" language] "?" encoded-text "?="
*/
if (MustEncode(text))
{
StringBuilder retVal = new StringBuilder();
byte[] data = charset.GetBytes(text);
int maxEncodedTextSize = 75 - ((string)("=?" + charset.WebName + "?" + encoding.ToString() + "?" + "?=")).Length;
#region B encode
if (encoding == MIME_EncodedWordEncoding.B)
{
retVal.Append("=?" + charset.WebName + "?B?");
int stored = 0;
string base64 = Convert.ToBase64String(data);
for (int i = 0; i < base64.Length; i += 4)
{
// Encoding buffer full, create new encoded-word.
if (stored + 4 > maxEncodedTextSize)
{
retVal.Append("?=\r\n =?" + charset.WebName + "?B?");
stored = 0;
}
retVal.Append(base64, i, 4);
stored += 4;
}
retVal.Append("?=");
}
#endregion
#region Q encode
else
{
retVal.Append("=?" + charset.WebName + "?Q?");
int stored = 0;
foreach (byte b in data)
{
string val = null;
// We need to encode byte. Defined in RFC 2047 4.2.
if (b > 127 || b == '=' || b == '?' || b == '_' || b == ' ')
{
val = "=" + b.ToString("X2");
}
else
{
val = ((char)b).ToString();
}
// Encoding buffer full, create new encoded-word.
if (stored + val.Length > maxEncodedTextSize)
{
retVal.Append("?=\r\n =?" + charset.WebName + "?Q?");
stored = 0;
}
retVal.Append(val);
stored += val.Length;
}
retVal.Append("?=");
}
#endregion
return(retVal.ToString());
}
else
{
return(text);
}
}
/// <summary>
/// Encodes specified text if it contains 8-bit chars, otherwise text won't be encoded.
/// </summary>
/// <param name="encoding">Encoding to use to encode text.</param>
/// <param name="charset">Charset to use for encoding. If not sure UTF-8 is strongly recommended.</param>
/// <param name="text">Text to encode.</param>
/// <returns>Returns encoded text.</returns>
/// <exception cref="ArgumentNullException">Is raised when <b>charset</b> or <b>text</b> is null reference.</exception>
public static string EncodeS(MIME_EncodedWordEncoding encoding,Encoding charset,string text)
{
if(charset == null){
throw new ArgumentNullException("charset");
}
if(text == null){
throw new ArgumentNullException("text");
}
/* RFC 2047 2.
encoded-word = "=?" charset "?" encoding "?" encoded-text "?="
An 'encoded-word' may not be more than 75 characters long, including
'charset', 'encoding', 'encoded-text', and delimiters. If it is
desirable to encode more text than will fit in an 'encoded-word' of
75 characters, multiple 'encoded-word's (separated by CRLF SPACE) may
be used.
RFC 2231 (updates syntax)
encoded-word := "=?" charset ["*" language] "?" encoded-text "?="
*/
if(MustEncode(text)){
StringBuilder retVal = new StringBuilder();
byte[] data = charset.GetBytes(text);
int maxEncodedTextSize = 75 - ((string)("=?" + charset.WebName + "?" + encoding.ToString() + "?" + "?=")).Length;
#region B encode
if(encoding == MIME_EncodedWordEncoding.B){
retVal.Append("=?" + charset.WebName + "?B?");
int stored = 0;
string base64 = Convert.ToBase64String(data);
for(int i=0;i<base64.Length;i+=4){
// Encoding buffer full, create new encoded-word.
if(stored + 4 > maxEncodedTextSize){
retVal.Append("?=\r\n =?" + charset.WebName + "?B?");
stored = 0;
}
retVal.Append(base64,i,4);
stored += 4;
}
retVal.Append("?=");
}
#endregion
#region Q encode
else{
retVal.Append("=?" + charset.WebName + "?Q?");
int stored = 0;
foreach(byte b in data){
string val = null;
// We need to encode byte. Defined in RFC 2047 4.2.
if(b > 127 || b == '=' || b == '?' || b == '_' || b == ' '){
val = "=" + b.ToString("X2");
}
else{
val = ((char)b).ToString();
}
// Encoding buffer full, create new encoded-word.
if(stored + val.Length > maxEncodedTextSize){
retVal.Append("?=\r\n =?" + charset.WebName + "?Q?");
stored = 0;
}
retVal.Append(val);
stored += val.Length;
}
retVal.Append("?=");
}
#endregion
return retVal.ToString();
}
else{
return text;
}
}
