private static PredictionContext AppendContext(PredictionContext context, PredictionContext suffix, PredictionContext.IdentityHashMap visited)
{
if (suffix.IsEmpty)
{
if (IsEmptyLocal(suffix))
{
if (context.HasEmpty)
{
return EmptyLocal;
}
throw new NotSupportedException("what to do here?");
}
return context;
}
if (suffix.Size != 1)
{
throw new NotSupportedException("Appending a tree suffix is not yet supported.");
}
PredictionContext result;
if (!visited.TryGetValue(context, out result))
{
if (context.IsEmpty)
{
result = suffix;
}
else
{
int parentCount = context.Size;
if (context.HasEmpty)
{
parentCount--;
}
PredictionContext[] updatedParents = new PredictionContext[parentCount];
int[] updatedReturnStates = new int[parentCount];
for (int i = 0; i < parentCount; i++)
{
updatedReturnStates[i] = context.GetReturnState(i);
}
for (int i_1 = 0; i_1 < parentCount; i_1++)
{
updatedParents[i_1] = AppendContext(context.GetParent(i_1), suffix, visited);
}
if (updatedParents.Length == 1)
{
result = new SingletonPredictionContext(updatedParents[0], updatedReturnStates[0]);
}
else
{
System.Diagnostics.Debug.Assert(updatedParents.Length > 1);
result = new Antlr4.Runtime.Atn.ArrayPredictionContext(updatedParents, updatedReturnStates);
}
if (context.HasEmpty)
{
result = PredictionContext.Join(result, suffix);
}
}
visited[context] = result;
}
return result;
}
