private static INfa Any()
{
var start = new NfaState();
var end = new NfaState();
start.AddTransistion(new TerminalNfaTransition(new AnyTerminal(), end));
return new Nfa(start, end);
}
private static INfa Character(RegexCharacter character)
{
var start = new NfaState();
var end = new NfaState();
var terminal = new CharacterTerminal(character.Value);
var transition = new TerminalNfaTransition(
terminal: terminal,
target: end);
start.AddTransistion(transition);
return new Nfa(start, end);
}
private static INfa Character(RegexCharacterClassCharacter character, bool negate)
{
var start = new NfaState();
var end = new NfaState();
ITerminal terminal = new CharacterTerminal(character.Value);
if (negate)
terminal = new NegationTerminal(terminal);
var transition = new TerminalNfaTransition(
terminal: terminal,
target: end);
start.AddTransistion(transition);
return new Nfa(start, end);
}
private static NfaClosure Closure(IEnumerable <NfaState> states, NfaState endState)
{
var set = ObjectPoolExtensions.Allocate(SharedPools.Default <HashSet <NfaState> >());
var isFinal = false;
foreach (var state in states)
{
foreach (var item in state.Closure())
{
if (item.Equals(endState))
{
isFinal = true;
}
set.Add(item);
}
}
return(new NfaClosure(set, isFinal));
}
public TerminalNfaTransition(AtomTerminal terminal, NfaState target)
: base(target)
{
Terminal = terminal;
}
public void AddTransition(AtomTerminal terminal, NfaState target)
{
AddTransition(new TerminalNfaTransition(terminal, target));
}
public void AddEpsilon(NfaState target)
{
AddTransition(new EpsilonNfaTransition(target));
}
private static NfaState[] CreateStates(int count)
{
var states = new NfaState[count];
for (int i = 0; i < states.Length; i++)
states[i] = new EntityNfaState(i);
return states;
}
private static INfa Empty()
{
var start = new NfaState();
var end = new NfaState();
start.AddTransistion(new NullNfaTransition(end));
return new Nfa(start, end);
}
private static INfa Union(INfa first, INfa second)
{
var start = new NfaState();
start.AddTransistion(new NullNfaTransition(first.Start));
start.AddTransistion(new NullNfaTransition(second.Start));
var end = new NfaState();
var endTransition = new NullNfaTransition(end);
first.End.AddTransistion(endTransition);
second.End.AddTransistion(endTransition);
return new Nfa(start, end);
}
private static INfa Range(RegexCharacterRange range, bool negate)
{
// combine characters into a character range terminal
var start = range.StartCharacter.Value;
var end = range.EndCharacter.Value;
ITerminal terminal = new RangeTerminal(start, end);
var nfaStartState = new NfaState();
var nfaEndState = new NfaState();
if (negate)
terminal = new NegationTerminal(terminal);
nfaStartState.AddTransistion(
new TerminalNfaTransition(terminal, nfaEndState));
return new Nfa(nfaStartState, nfaEndState);
}
private static INfa Optional(INfa nfa)
{
var start = new NfaState();
var end = new NfaState();
start.AddTransistion(new NullNfaTransition(nfa.Start));
start.AddTransistion(new NullNfaTransition(end));
nfa.End.AddTransistion(new NullNfaTransition(end));
return new Nfa(start, end);
}
private static INfa KleeneStar(INfa nfa)
{
var start = new NfaState();
var nullToNfaStart = new NullNfaTransition(nfa.Start);
start.AddTransistion(nullToNfaStart);
nfa.End.AddTransistion(nullToNfaStart);
var end = new NfaState();
var nullToNewEnd = new NullNfaTransition(end);
start.AddTransistion(nullToNewEnd);
nfa.End.AddTransistion(nullToNewEnd);
return new Nfa(start, end);
}
private static INfa KleenePlus(INfa nfa)
{
var end = new NfaState();
nfa.End.AddTransistion(new NullNfaTransition(end));
nfa.End.AddTransistion(new NullNfaTransition(nfa.Start));
return new Nfa(nfa.Start, end);
}
