public static VoteLine?ParseLine(ReadOnlySpan <char> line)
{
if (line.Length == 0)
{
return(null);
}
StringBuilder prefixSB = new StringBuilder();
StringBuilder markerSB = new StringBuilder();
StringBuilder taskSB = new StringBuilder();
StringBuilder contentSB = new StringBuilder();
StringBuilder tempContent = new StringBuilder();
MarkerType markerType = MarkerType.None;
int markerValue = 0;
Stack <TokenState> state = new Stack <TokenState>();
TokenState currentState = TokenState.None;
for (int c = 0; c < line.Length; c++)
{
char ch = line[c];
// Skip newlines entirely, if they somehow get into the line we're parsing.
if (newlineChars.Contains(ch))
{
continue;
}
switch (currentState)
{
case TokenState.None:
if (ch == whitespace)
{
continue;
}
else if (prefixChars.Contains(ch))
{
prefixSB.Append(ch);
currentState = TokenState.Prefix;
}
else if (ch == openBracket)
{
currentState = TokenState.Marker;
}
else if (ch == xBox || ch == checkBox)
{
// Shortcut for a complete marker
markerSB.Append(ch);
(markerType, markerValue) = GetMarkerType(markerSB.ToString());
currentState = TokenState.PostMarker;
}
else if (ch == openBBCode)
{
state.Push(currentState);
currentState = TokenState.BBCode;
}
else
{
goto doneExamining;
}
break;
case TokenState.Prefix:
if (ch == whitespace)
{
continue;
}
else if (prefixChars.Contains(ch))
{
prefixSB.Append(ch);
}
else if (ch == openBracket)
{
currentState = TokenState.Marker;
}
else if (ch == xBox || ch == checkBox)
{
// Shortcut for a complete marker
markerSB.Append(ch);
(markerType, markerValue) = GetMarkerType(markerSB.ToString());
currentState = TokenState.PostMarker;
}
else if (ch == openBBCode)
{
state.Push(currentState);
currentState = TokenState.BBCode;
}
else
{
goto doneExamining;
}
break;
case TokenState.Marker:
if (ch == whitespace)
{
continue;
}
else if (markerChars.Contains(ch))
{
markerSB.Append(ch);
}
else if (ch == closeBracket)
{
(markerType, markerValue) = GetMarkerType(markerSB.ToString());
if (markerType != MarkerType.None)
{
currentState = TokenState.PostMarker;
}
else
{
goto doneExamining;
}
}
else if (ch == openBBCode)
{
state.Push(currentState);
currentState = TokenState.BBCode;
}
else
{
goto doneExamining;
}
break;
case TokenState.PostMarker:
if (ch == whitespace)
{
if (tempContent.Length > 0)
{
tempContent.Append(ch);
}
continue;
}
else if (ch == openBracket && taskSB.Length == 0)
{
state.Push(currentState);
currentState = TokenState.Task;
}
else if (ch == openBBCode && taskSB.Length == 0)
{
state.Push(currentState);
currentState = TokenState.BBCode;
tempContent.Append(ch);
}
else if (ch == openStrike)
{
tempContent.Append("『s』");
state.Push(currentState);
currentState = TokenState.Strike;
}
else
{
contentSB.Append(tempContent);
tempContent.Clear();
contentSB.Append(ch);
currentState = TokenState.Content;
}
break;
case TokenState.Task:
tempContent.Clear();
if (ch == closeBracket)
{
currentState = state.Pop();
}
else if (ch == openBBCode)
{
state.Push(currentState);
currentState = TokenState.BBCode;
}
else if (ch == openStrike)
{
state.Push(currentState);
currentState = TokenState.Strike;
}
else
{
taskSB.Append(ch);
}
break;
case TokenState.Content:
if (tempContent.Length > 0)
{
contentSB.Append(tempContent);
tempContent.Clear();
}
if (ch == openStrike)
{
tempContent.Append("『s』");
state.Push(currentState);
currentState = TokenState.Strike;
}
else if (apostraphes.Contains(ch))
{
contentSB.Append('\'');
}
else if (quotations.Contains(ch))
{
contentSB.Append('"');
}
else
{
contentSB.Append(ch);
}
break;
case TokenState.BBCode:
if (state.Peek() == TokenState.PostMarker)
{
tempContent.Append(ch);
}
if (ch == closeBBCode)
{
currentState = state.Pop();
}
break;
case TokenState.Strike:
// Strike-through text is only preserved in the content area
if (ch == closeStrike)
{
tempContent.Append("『/s』");
currentState = state.Pop();
}
else if (ch == strikeNewline)
{
// If we hit embedded newlines, bail out entirely.
// Take whatever's been done up to that point.
tempContent.Clear();
currentState = state.Pop();
goto doneExamining;
}
else
{
tempContent.Append(ch);
}
break;
default:
throw new InvalidOperationException($"Unknown token state value: {currentState}.");
}
}
doneExamining:
if (currentState == TokenState.Content)
{
string content = VoteString.NormalizeContentBBCode(contentSB.ToString());
return(new VoteLine(prefixSB.ToString(), markerSB.ToString(), taskSB.ToString(), content, markerType, markerValue));
}
return(null);
}
