/// <summary>
/// Initializes this dfa as equivalent to the given nfa
/// </summary>
/// <param name="nfa">A nfa</param>
public DFA(NFA nfa)
{
states = new List <DFAState>();
List <NFAStateSet> nfaStateSets = new List <NFAStateSet>();
// Create the first NFA set, add the entry and close it
NFAStateSet nfaInit = new NFAStateSet();
nfaStateSets.Add(nfaInit);
nfaInit.Add(nfa.StateEntry);
nfaInit.Close();
// Create the initial state for the DFA
DFAState dfaInit = new DFAState(0);
states.Add(dfaInit);
// For each set in the list of the NFA states
for (int i = 0; i != nfaStateSets.Count; i++)
{
// Normalize transitions
nfaStateSets[i].Normalize();
// Get the transitions for the set
Dictionary <CharSpan, NFAStateSet> transitions = nfaStateSets[i].GetTransitions();
// For each transition
foreach (CharSpan value in transitions.Keys)
{
// The child by the transition
NFAStateSet next = transitions[value];
// Search for the child in the existing sets
bool found = false;
for (int j = 0; j != nfaStateSets.Count; j++)
{
// An existing equivalent set is already present
if (nfaStateSets[j].Equals(next))
{
states[i].AddTransition(value, states[j]);
found = true;
break;
}
}
// The child is not already present
if (!found)
{
// Add to the sets list
nfaStateSets.Add(next);
// Create the corresponding DFA state
DFAState newState = new DFAState(states.Count);
states.Add(newState);
// Setup transition
states[i].AddTransition(value, newState);
}
}
// Add finals
states[i].AddItems(nfaStateSets[i].GetFinals());
}
}
/// <summary>
/// Determines whether the given object is equal to this set
/// </summary>
/// <param name="obj">The object to compare</param>
/// <returns>True of the object is equal to this set</returns>
public override bool Equals(object obj)
{
NFAStateSet right = obj as NFAStateSet;
if (right == null)
{
return(false);
}
if (backend.Count != right.backend.Count)
{
return(false);
}
foreach (NFAState state in backend)
{
if (!right.backend.Contains(state))
{
return(false);
}
}
return(true);
}
/// <summary>
/// Gets transitions from this set to other sets
/// </summary>
/// <returns>The transitions from this set to other sets</returns>
public Dictionary <CharSpan, NFAStateSet> GetTransitions()
{
Dictionary <CharSpan, NFAStateSet> transitions = new Dictionary <CharSpan, NFAStateSet>();
// For each state
foreach (NFAState State in backend)
{
// For each transition
foreach (NFATransition transition in State.Transitions)
{
// If this is an ε-transition : pass
if (transition.Span.Equals(NFA.EPSILON))
{
continue;
}
// Add the transition's target to set's transitions dictionnary
if (transitions.ContainsKey(transition.Span))
{
transitions[transition.Span].Add(transition.Next);
}
else
{
// Create a new child
NFAStateSet set = new NFAStateSet();
set.Add(transition.Next);
transitions.Add(transition.Span, set);
}
}
}
// Close all children
foreach (NFAStateSet set in transitions.Values)
{
set.Close();
}
return(transitions);
}
