/// <summary>
/// Parses the given <paramref name="rtfText"/>
/// </summary>
/// <param name="rtfText">text</param>
public void ParseRtfText(string rtfText)
{
HtmlContent = null;
var stringBuilder = new StringBuilder();
var htmlExtraction = false;
var rtfContaintsEmbeddedHtml = false;
var hexBuffer = string.Empty;
using (var stringReader = new StringReader(rtfText))
using (var reader = new Reader(stringReader))
{
while (reader.ReadToken() != null)
{
if (reader.LastToken?.Key == "'" &&
reader?.Keyword != "'" &&
hexBuffer != string.Empty &&
!RuntimeEncoding.IsSingleByte)
{
var value = HexValueToChar(hexBuffer);
if (value != null)
{
stringBuilder.Append(value);
}
else
{
// Double byte charset was detected for the last token but only one byte was used so far.
// This token should carry the second byte but it doesn't.
// Workaround: To display it anyway, we treat it as a single byte char.
var buff = new[] { byte.Parse(hexBuffer, NumberStyles.HexNumber) };
stringBuilder.Append(RuntimeEncoding.GetString(buff));
}
hexBuffer = string.Empty;
if (reader.TokenType == RtfTokenType.Text)
{
stringBuilder.Append(reader.Keyword);
continue;
}
}
switch (reader.Keyword)
{
case Consts.Ansi:
break;
case Consts.Ansicpg:
// Read default encoding
_defaultEncoding = Encoding.GetEncoding(reader.Parameter);
break;
case Consts.Info:
// Read document information
ReadDocumentInfo(reader);
return;
case Consts.FromHtml:
rtfContaintsEmbeddedHtml = true;
htmlExtraction = true;
break;
case Consts.Generator:
// Read document generator
Generator = ReadInnerText(reader, true);
break;
case Consts.FormatConverter:
FormatConverter = ReadInnerText(reader, true);
break;
case Consts.Fonttbl:
// Read font table
ReadFontTable(reader);
break;
case Consts.F:
if (reader.TokenType == RtfTokenType.Text)
{
goto default;
}
try
{
_fontChartset = FontTable[reader.Parameter].Encoding;
}
catch
{
_fontChartset = Encoding.Default;
}
break;
case Consts.Af:
_associateFontChartset = FontTable[reader.Parameter].Encoding;
break;
case Consts.HtmlRtf:
switch (reader.HasParam)
{
case false:
htmlExtraction = true;
break;
case true when reader.Parameter == 0:
htmlExtraction = false;
break;
}
break;
case Consts.MHtmlTag:
if (reader.HasParam && reader.Parameter == 0)
{
htmlExtraction = false;
}
else
{
if (hexBuffer != string.Empty)
{
var buff = new[] { byte.Parse(hexBuffer, NumberStyles.HexNumber) };
hexBuffer = string.Empty;
stringBuilder.Append(RuntimeEncoding.GetString(buff));
htmlExtraction = true;
}
else
{
htmlExtraction = false;
}
}
break;
case Consts.HtmlTag:
{
if (reader.InnerReader.Peek() == ' ')
{
reader.InnerReader.Read();
}
var text = ReadInnerText(reader, null, true, false, true);
if (!string.IsNullOrEmpty(text))
{
stringBuilder.Append(text);
}
break;
}
case Consts.HtmlBase:
{
var text = ReadInnerText(reader, null, true, false, true);
if (!string.IsNullOrEmpty(text))
{
stringBuilder.Append(text);
}
break;
}
case Consts.Background:
case Consts.Fillcolor:
case Consts.Field:
ReadInnerText(reader, null, false, true, false);
break;
//case Consts.Par:
//case Consts.Line:
// stringBuilder.Append(Environment.NewLine);
// break;
case Consts.Tab:
stringBuilder.Append("\t");
break;
case Consts.Lquote:
stringBuilder.Append("‘");
break;
case Consts.Rquote:
stringBuilder.Append("’");
break;
case Consts.LdblQuote:
stringBuilder.Append("“");
break;
case Consts.RdblQuote:
stringBuilder.Append("”");
break;
case Consts.Bullet:
stringBuilder.Append("•");
break;
case Consts.Endash:
stringBuilder.Append("–");
break;
case Consts.Emdash:
stringBuilder.Append("—");
break;
case Consts.Tilde:
stringBuilder.Append(" ");
break;
case Consts.Underscore:
stringBuilder.Append("­");
break;
case Consts.Pntext:
reader.ReadToEndOfGroup();
break;
case Consts.U:
//if (reader.TokenType == RtfTokenType.Control && !htmlExtraction)
//{
// stringBuilder.Append(HttpUtility.UrlDecode("*", _defaultEncoding));
// continue;
//}
if (reader.Parameter.ToString().StartsWith("c", StringComparison.InvariantCultureIgnoreCase))
{
throw new Exception("\\uc parameter not yet supported, please contact the developer on GitHub");
}
if (reader.Parameter.ToString().StartsWith("-"))
{
// The Unicode standard permanently reserves these code point values for
// UTF-16 encoding of the high and low surrogates
// U+D800 to U+DFFF
// 55296 - 57343
var value = 65536 + int.Parse(reader.Parameter.ToString());
if (value >= 0xD800 && value <= 0xDFFF)
{
if (!reader.ParsingHighLowSurrogate)
{
reader.ParsingHighLowSurrogate = true;
reader.HighSurrogateValue = value;
}
else
{
var combined = ((reader.HighSurrogateValue - 0xD800) << 10) + (value - 0xDC00) + 0x10000;
stringBuilder.Append($"&#{combined};");
reader.ParsingHighLowSurrogate = false;
reader.HighSurrogateValue = null;
}
}
else
{
reader.ParsingHighLowSurrogate = false;
stringBuilder.Append($"&#{value};");
}
}
else
{
stringBuilder.Append($"&#{reader.Parameter};");
}
break;
case Consts.Apostrophe:
if (reader.TokenType != RtfTokenType.Control || htmlExtraction)
{
continue;
}
// Convert HEX value directly when we have a single byte charset
if (RuntimeEncoding.IsSingleByte)
{
if (string.IsNullOrEmpty(hexBuffer))
{
hexBuffer = reader.CurrentToken.Hex;
}
var buff = new[] { byte.Parse(hexBuffer, NumberStyles.HexNumber) };
hexBuffer = string.Empty;
stringBuilder.Append(RuntimeEncoding.GetString(buff));
}
else
{
// If we have a double byte charset like Chinese then store the value and wait for the next HEX value
if (hexBuffer == string.Empty)
{
hexBuffer = reader.CurrentToken.Hex;
}
else
{
// Append the second HEX value and convert it
var buff = new[]
{
byte.Parse(hexBuffer, NumberStyles.HexNumber),
byte.Parse(reader.CurrentToken.Hex, NumberStyles.HexNumber)
};
stringBuilder.Append(RuntimeEncoding.GetString(buff));
// Empty the HEX buffer
hexBuffer = string.Empty;
}
}
break;
default:
switch (reader.TokenType)
{
//case RtfTokenType.GroupEnd:
// htmlExtraction = false;
// break;
case RtfTokenType.Text:
if (!htmlExtraction)
{
stringBuilder.Append(reader.Keyword);
}
break;
}
break;
}
}
}
if (rtfContaintsEmbeddedHtml)
{
HtmlContent = stringBuilder.ToString();
}
}
/// <summary>
/// Reads the font table
/// </summary>
/// <param name="reader"></param>
private void ReadFontTable(Reader reader)
{
FontTable.Clear();
while (reader.ReadToken() != null)
{
if (reader.TokenType == RtfTokenType.GroupEnd)
{
break;
}
if (reader.TokenType != RtfTokenType.GroupStart)
{
continue;
}
var index = -1;
string name = null;
var charset = 1;
var nilFlag = false;
while (reader.ReadToken() != null)
{
if (reader.TokenType == RtfTokenType.GroupEnd)
{
break;
}
if (reader.TokenType == RtfTokenType.GroupStart)
{
// If we meet nested levels, then ignore
reader.ReadToken();
reader.ReadToEndOfGroup();
reader.ReadToken();
}
else
{
switch (reader.Keyword)
{
case "f" when reader.HasParam:
index = reader.Parameter;
break;
case "fnil":
name = SystemFonts.DefaultFont.Name;
nilFlag = true;
break;
case Consts.Fcharset:
charset = reader.Parameter;
break;
default:
if (reader.CurrentToken.IsTextToken)
{
name = ReadInnerText(reader, reader.CurrentToken, false, false, false);
if (name != null)
{
name = name.Trim();
if (name.EndsWith(";"))
{
name = name.Substring(0, name.Length - 1);
}
}
}
break;
}
}
}
if (index < 0 || name == null)
{
continue;
}
if (name.EndsWith(";"))
{
name = name.Substring(0, name.Length - 1);
}
name = name.Trim();
if (string.IsNullOrEmpty(name))
{
name = SystemFonts.DefaultFont.Name;
}
var font = new Font(index, name)
{
Charset = charset, NilFlag = nilFlag
};
FontTable.Add(font);
}
}