public virtual int Mark()
{
if (markers == null)
{
markers = new List <CharStreamState>();
markers.Add(null); // depth 0 means no backtracking, leave blank
}
markDepth++;
CharStreamState state = null;
if (markDepth >= markers.Count)
{
state = new CharStreamState();
markers.Add(state);
}
else
{
state = markers[markDepth];
}
state.p = p;
state.line = line;
state.charPositionInLine = charPositionInLine;
lastMarker = markDepth;
return(markDepth);
}
public virtual void Rewind(int m)
{
if (m < 0)
{
throw new ArgumentOutOfRangeException();
}
//if (m > markDepth)
// throw new ArgumentException();
CharStreamState state = markers[m];
// restore stream state
Seek(state.p);
line = state.line;
charPositionInLine = state.charPositionInLine;
Release(m);
}