/** * Calculates the set of states that can be reached from another * set of states <code>start</code> with an specified input * character <code>input</code> * * @param start the set of states to start from * @param input the input character for which to search the next states * * @return the set of states that are reached from <code>start</code> * via <code>input</code> */ private StateSet DFAEdge(StateSet start, char input) { // Out.debug("Calculating DFAEdge for state set "+start+" and input '"+input+"'"); tempStateSet.clear(); states.reset(start); while (states.hasMoreElements()) { tempStateSet.add(table[states.nextElement()][input]); } StateSet result = new StateSet(tempStateSet); states.reset(tempStateSet); while (states.hasMoreElements()) { result.add(epsilon[states.nextElement()]); } // Out.debug("DFAEdge is : "+result); return(result); }
private int _dfaStart; // in nfa coordinates private void removeDead(int start) { // Out.debug("removeDead ("+start+")"); if (visited[start] || live[start]) { return; } visited[start] = true; // Out.debug("not yet visited"); if (closure(start).isElement(_end)) { live[start] = true; } // Out.debug("is final :"+live[start]); for (int i = 0; i < numInput; i++) { StateSet nextState = closure(table[start][i]); StateSetEnumerator states = nextState.states(); while (states.hasMoreElements()) { int next = states.nextElement(); if (next != start) { removeDead(next); if (live[next]) { live[start] = true; } else { table[start][i] = null; } } } } StateSet _nextState = closure(epsilon[start]); StateSetEnumerator _states = _nextState.states(); while (_states.hasMoreElements()) { int next = _states.nextElement(); if (next != start) { removeDead(next); if (live[next]) { live[start] = true; } } } // Out.debug("state "+start+" is live :"+live[start]); }
/** * Returns an DFA that accepts the same language as this NFA. * This DFA is usualy not minimal. */ public DFA getDFA() { Hashtable dfaStates = new PrettyHashtable(numStates); ArrayList dfaVector = new PrettyArrayList(numStates); DFA dfa = new DFA(2 * numLexStates, numInput); int numDFAStates = 0; int currentDFAState = 0; Out.println("Converting NFA to DFA : "); epsilonFill(); StateSet currentState, newState; for (int i = 0; i < 2 * numLexStates; i++) { newState = epsilon[i]; dfaStates[newState] = new Integer(numDFAStates); dfaVector.Add(newState); dfa.setLexState(i, numDFAStates); dfa.setFinal(numDFAStates, containsFinal(newState)); dfa.setPushback(numDFAStates, containsPushback(newState)); dfa.setAction(numDFAStates, getAction(newState)); numDFAStates++; } numDFAStates--; if (Options.DEBUG) { Out.debug("DFA start states are :" + Out.NL + dfaStates + Out.NL + Out.NL + "ordered :" + Out.NL + dfaVector); } currentDFAState = 0; StateSet tempStateSet = NFA.tempStateSet; StateSetEnumerator states = NFA.states; // will be reused newState = new StateSet(numStates); while (currentDFAState <= numDFAStates) { currentState = (StateSet)dfaVector[currentDFAState]; for (char input = (char)0; input < numInput; input++) { // newState = DFAEdge(currentState, input); // inlining DFAEdge for performance: // Out.debug("Calculating DFAEdge for state set "+currentState+" and input '"+input+"'"); tempStateSet.clear(); states.reset(currentState); while (states.hasMoreElements()) { tempStateSet.add(table[states.nextElement()][input]); } newState.copy(tempStateSet); states.reset(tempStateSet); while (states.hasMoreElements()) { newState.add(epsilon[states.nextElement()]); } // Out.debug("DFAEdge is : "+newState); if (newState.containsElements()) { // Out.debug("DFAEdge for input "+(int)input+" and state set "+currentState+" is "+newState); // Out.debug("Looking for state set "+newState); Integer nextDFAState = (Integer)dfaStates[newState]; if (nextDFAState != null) { // Out.debug("FOUND!"); dfa.addTransition(currentDFAState, input, nextDFAState.intValue()); } else { if (Options.progress) { Out.print("."); } // Out.debug("NOT FOUND!"); // Out.debug("Table was "+dfaStates); numDFAStates++; // make a new copy of newState to store in dfaStates StateSet storeState = new StateSet(newState); dfaStates[storeState] = new Integer(numDFAStates); dfaVector.Add(storeState); dfa.addTransition(currentDFAState, input, numDFAStates); dfa.setFinal(numDFAStates, containsFinal(storeState)); dfa.setPushback(numDFAStates, containsPushback(storeState)); dfa.setAction(numDFAStates, getAction(storeState)); } } } currentDFAState++; } if (Options.verbose) { Out.println(""); } return(dfa); }
public StateSet(StateSet set) { bits = new long[set.bits.Length]; Array.Copy(set.bits, 0, bits, 0, set.bits.Length); }