private int traverseStates(string word)
{
Queue <RegularState> queue = new Queue <RegularState>(states);
Set <RegularState> visited = new Set <RegularState>();
states.Clear();
while (queue.Count > 0)
{
RegularState state = queue.Dequeue();
hasGreedyEnd = state.isGreedyEnd();
if (hasGreedyEnd)
{
return(0);
}
visited.Add(state);
foreach (RegularTransition rt in state.getOutTransitions())
{
if (rt.isEmpty())
{
RegularState rst = rt.getEndState();
if (!queue.Contains(rst) && !visited.Contains(rst))
{
queue.Enqueue(rst);
}
}
else if (rt.match(word))
{
addState(rt.getEndState());
}
}
}
return(states.Count);
}
/// <summary>
/// Replace end states in all transitions starting from base
/// </summary>
/// <param name="instat"></param>
/// <param name="from"></param>
/// <param name="to"></param>
private static void replaceStates(RegularState instat, RegularState from, RegularState to)
{
Stack <RegularState> states = new Stack <RegularState>();
states.Push(instat);
Set <RegularState> visited = new Set <RegularState>();
visited.Add(to);
while (states.Count > 0)
{
RegularState state = states.Pop();
visited.Add(state);
foreach (RegularTransition rt in state.getOutTransitions())
{
if (rt.getEndState().Equals(from))
{
rt.setEndState(to);
continue;
}
RegularState st = rt.getEndState();
if (!visited.Contains(st))
{
states.Push(st);
}
}
}
}
private void addState(RegularState state)
{
if (states.Contains(state))
{
return;
}
states.Add(state);
// add lambda transitions
foreach (RegularTransition rt in state.getOutTransitions())
{
if (rt.isEmpty())
{
addState(rt.getEndState());
}
}
}
/// <summary>
/// Return true when the provided state has a path to itself
/// </summary>
/// <param name="self"></param>
/// <returns></returns>
private static bool hasSelfReference(RegularState self)
{
Stack <RegularState> states = new Stack <RegularState>();
states.Push(self);
Set <RegularState> visited = new Set <RegularState>();
while (states.Count > 0)
{
RegularState state = states.Pop();
visited.Add(state);
foreach (RegularTransition rt in state.getOutTransitions())
{
if (rt.getEndState().Equals(self))
{
return(true);
}
}
}
return(false);
}
