SubtitleEdit/libse/RichTextToPlainText.cs
2019-01-19 14:40:37 +01:00

271 lines
12 KiB
C#

using Nikse.SubtitleEdit.Core.Interfaces;
using System;
using System.Collections.Generic;
using System.Text;
using System.Text.RegularExpressions;
namespace Nikse.SubtitleEdit.Core
{
/// <summary>
/// Rich Text to plain text
/// </summary>
/// <remarks>
/// Translated from Python located at:
/// http://stackoverflow.com/a/188877/448
/// to C# by Chris Benard - http://chrisbenard.net/2014/08/20/Extract-Text-from-RTF-in-.Net
/// </remarks>
public static class RichTextToPlainText
{
public static IRtfTextConverter NativeRtfTextConverter { get; set; }
private class StackEntry
{
public int NumberOfCharactersToSkip { get; private set; }
public bool Ignorable { get; private set; }
public StackEntry(int numberOfCharactersToSkip, bool ignorable)
{
NumberOfCharactersToSkip = numberOfCharactersToSkip;
Ignorable = ignorable;
}
}
private static readonly Regex RtfRegex = new Regex(@"\\([a-z]{1,32})(-?\d{1,10})?[ ]?|\\'([0-9a-f]{2})|\\([^a-z])|([{}])|[\r\n]+|(.)", RegexOptions.Singleline | RegexOptions.IgnoreCase);
private static readonly List<string> Destinations = new List<string>
{
"aftncn","aftnsep","aftnsepc","annotation","atnauthor","atndate","atnicn","atnid",
"atnparent","atnref","atntime","atrfend","atrfstart","author","background",
"bkmkend","bkmkstart","blipuid","buptim","category","colorschememapping",
"colortbl","comment","company","creatim","datafield","datastore","defchp","defpap",
"do","doccomm","docvar","dptxbxtext","ebcend","ebcstart","factoidname","falt",
"fchars","ffdeftext","ffentrymcr","ffexitmcr","ffformat","ffhelptext","ffl",
"ffname","ffstattext","field","file","filetbl","fldinst","fldrslt","fldtype",
"fname","fontemb","fontfile","fonttbl","footer","footerf","footerl","footerr",
"footnote","formfield","ftncn","ftnsep","ftnsepc","g","generator","gridtbl",
"header","headerf","headerl","headerr","hl","hlfr","hlinkbase","hlloc","hlsrc",
"hsv","htmltag","info","keycode","keywords","latentstyles","lchars","levelnumbers",
"leveltext","lfolevel","linkval","list","listlevel","listname","listoverride",
"listoverridetable","listpicture","liststylename","listtable","listtext",
"lsdlockedexcept","macc","maccPr","mailmerge","maln","malnScr","manager","margPr",
"mbar","mbarPr","mbaseJc","mbegChr","mborderBox","mborderBoxPr","mbox","mboxPr",
"mchr","mcount","mctrlPr","md","mdeg","mdegHide","mden","mdiff","mdPr","me",
"mendChr","meqArr","meqArrPr","mf","mfName","mfPr","mfunc","mfuncPr","mgroupChr",
"mgroupChrPr","mgrow","mhideBot","mhideLeft","mhideRight","mhideTop","mhtmltag",
"mlim","mlimloc","mlimlow","mlimlowPr","mlimupp","mlimuppPr","mm","mmaddfieldname",
"mmath","mmathPict","mmathPr","mmaxdist","mmc","mmcJc","mmconnectstr",
"mmconnectstrdata","mmcPr","mmcs","mmdatasource","mmheadersource","mmmailsubject",
"mmodso","mmodsofilter","mmodsofldmpdata","mmodsomappedname","mmodsoname",
"mmodsorecipdata","mmodsosort","mmodsosrc","mmodsotable","mmodsoudl",
"mmodsoudldata","mmodsouniquetag","mmPr","mmquery","mmr","mnary","mnaryPr",
"mnoBreak","mnum","mobjDist","moMath","moMathPara","moMathParaPr","mopEmu",
"mphant","mphantPr","mplcHide","mpos","mr","mrad","mradPr","mrPr","msepChr",
"mshow","mshp","msPre","msPrePr","msSub","msSubPr","msSubSup","msSubSupPr","msSup",
"msSupPr","mstrikeBLTR","mstrikeH","mstrikeTLBR","mstrikeV","msub","msubHide",
"msup","msupHide","mtransp","mtype","mvertJc","mvfmf","mvfml","mvtof","mvtol",
"mzeroAsc","mzeroDesc","mzeroWid","nesttableprops","nextfile","nonesttables",
"objalias","objclass","objdata","object","objname","objsect","objtime","oldcprops",
"oldpprops","oldsprops","oldtprops","oleclsid","operator","panose","password",
"passwordhash","pgp","pgptbl","picprop","pict","pn","pnseclvl","pntext","pntxta",
"pntxtb","printim","private","propname","protend","protstart","protusertbl","pxe",
"result","revtbl","revtim","rsidtbl","rxe","shp","shpgrp","shpinst",
"shppict","shprslt","shptxt","sn","sp","staticval","stylesheet","subject","sv",
"svb","tc","template","themedata","title","txe","ud","upr","userprops",
"wgrffmtfilter","windowcaption","writereservation","writereservhash","xe","xform",
"xmlattrname","xmlattrvalue","xmlclose","xmlname","xmlnstbl",
"xmlopen"
};
private static readonly Dictionary<string, string> SpecialCharacters = new Dictionary<string, string>
{
{ "par", "\n" },
{ "sect", "\n\n" },
{ "page", "\n\n" },
{ "line", "\n" },
{ "tab", "\t" },
{ "emdash", "\u2014" },
{ "endash", "\u2013" },
{ "emspace", "\u2003" },
{ "enspace", "\u2002" },
{ "qmspace", "\u2005" },
{ "bullet", "\u2022" },
{ "lquote", "\u2018" },
{ "rquote", "\u2019" },
{ "ldblquote", "\u201C" },
{ "rdblquote", "\u201D" },
};
/// <summary>
/// Strip RTF Tags from RTF Text
/// </summary>
/// <param name="inputRtf">RTF formatted text</param>
/// <returns>Plain text from RTF</returns>
internal static string ConvertToText(string inputRtf)
{
if (inputRtf == null)
{
return null;
}
// use interface converter if available
if (NativeRtfTextConverter != null)
{
NativeRtfTextConverter.RtfToText(inputRtf);
}
var stack = new Stack<StackEntry>();
bool ignorable = false; // Whether this group (and all inside it) are "ignorable".
int ucskip = 1; // Number of ASCII characters to skip after a unicode character.
int curskip = 0; // Number of ASCII characters left to skip
var outList = new List<string>(); // Output buffer.
MatchCollection matches = RtfRegex.Matches(inputRtf);
if (matches.Count > 0)
{
foreach (Match match in matches)
{
string word = match.Groups[1].Value;
string arg = match.Groups[2].Value;
string hex = match.Groups[3].Value;
string character = match.Groups[4].Value;
string brace = match.Groups[5].Value;
string tchar = match.Groups[6].Value;
if (!string.IsNullOrEmpty(brace))
{
curskip = 0;
if (brace == "{")
{
// Push state
stack.Push(new StackEntry(ucskip, ignorable));
}
else if (brace == "}")
{
// Pop state
StackEntry entry = stack.Pop();
ucskip = entry.NumberOfCharactersToSkip;
ignorable = entry.Ignorable;
}
}
else if (!string.IsNullOrEmpty(character)) // \x (not a letter)
{
curskip = 0;
if (character == "~")
{
if (!ignorable)
{
outList.Add("\xA0");
}
}
else if ("{}\\".Contains(character))
{
if (!ignorable)
{
outList.Add(character);
}
}
else if (character == "*")
{
ignorable = true;
}
}
else if (!string.IsNullOrEmpty(word)) // \foo
{
curskip = 0;
if (Destinations.Contains(word))
{
ignorable = true;
}
else if (ignorable)
{
}
else if (SpecialCharacters.ContainsKey(word))
{
outList.Add(SpecialCharacters[word]);
}
else if (word == "uc")
{
ucskip = int.Parse(arg);
}
else if (word == "u")
{
int c = int.Parse(arg);
if (c < 0)
{
c += 0x10000;
}
outList.Add(char.ConvertFromUtf32(c));
curskip = ucskip;
}
}
else if (!string.IsNullOrEmpty(hex)) // \'xx
{
if (curskip > 0)
{
curskip -= 1;
}
else if (!ignorable)
{
int c = int.Parse(hex, System.Globalization.NumberStyles.HexNumber);
outList.Add(char.ConvertFromUtf32(c));
}
}
else if (!string.IsNullOrEmpty(tchar))
{
if (curskip > 0)
{
curskip -= 1;
}
else if (!ignorable)
{
outList.Add(tchar);
}
}
}
}
return string.Join(string.Empty, outList.ToArray());
}
internal static string ConvertToRtf(string value)
{
if (string.IsNullOrWhiteSpace(value))
{
return string.Empty;
}
// use interface converter if available
if (NativeRtfTextConverter != null)
{
NativeRtfTextConverter.TextToRtf(value);
}
// special RTF chars
var backslashed = new StringBuilder(value);
backslashed.Replace(@"\", @"\\");
backslashed.Replace(@"{", @"\{");
backslashed.Replace(@"}", @"\}");
backslashed.Replace(Environment.NewLine, @"\par" + Environment.NewLine);
// convert string char by char
var sb = new StringBuilder();
foreach (char character in backslashed.ToString())
{
if (character <= 0x7f)
{
sb.Append(character);
}
else
{
sb.Append("\\u" + Convert.ToUInt32(character) + "?");
}
}
return @"{\rtf1\ansi\ansicpg1252\deff0{\fonttbl\f0\fswiss Helvetica;}\f0\pard " + sb + @"\par" + Environment.NewLine + "}";
}
}
}