void CAG_RegEx::ConvertNFAtoDFA()
{
// Clean up the DFA Table first
for(int i=0; i<m_DFATable.size(); ++i)
delete m_DFATable[i];
m_DFATable.clear();
// Check is NFA table empty
if(m_NFATable.size() == 0)
return;
// Reset the state id for new naming
m_nNextStateID = 0;
// Array of unprocessed DFA states
vector<CAG_State*> unmarkedStates;
// Starting state of DFA is epsilon closure of
// starting state of NFA state (set of states)
set<CAG_State*> DFAStartStateSet;
set<CAG_State*> NFAStartStateSet;
NFAStartStateSet.insert(m_NFATable[0]);
EpsilonClosure(NFAStartStateSet, DFAStartStateSet);
// Create new DFA State (start state) from the NFA states
CAG_State *DFAStartState = new CAG_State(DFAStartStateSet, ++m_nNextStateID);
// Add the start state to the DFA
m_DFATable.push_back(DFAStartState);
// Add the starting state to set of unprocessed DFA states
unmarkedStates.push_back(DFAStartState);
while(!unmarkedStates.empty())
{
// process an unprocessed state
CAG_State* processingDFAState = unmarkedStates[unmarkedStates.size()-1];
unmarkedStates.pop_back();
// for each input signal a
set<char>::iterator iter;
for(iter=m_InputSet.begin(); iter!=m_InputSet.end(); ++iter)
{
set<CAG_State*> MoveRes, EpsilonClosureRes;
Move(*iter, processingDFAState->GetNFAState(), MoveRes);
EpsilonClosure(MoveRes, EpsilonClosureRes);
// Check is the resulting set (EpsilonClosureSet) in the
// set of DFA states (is any DFA state already constructed
// from this set of NFA states) or in pseudocode:
// is U in D-States already (U = EpsilonClosureSet)
BOOL bFound = FALSE;
CAG_State *s = NULL;
for(i=0; i<m_DFATable.size(); ++i)
{
s = m_DFATable[i];
if(s->GetNFAState() == EpsilonClosureRes)
{
bFound = TRUE;
break;
}
}
if(!bFound)
{
CAG_State* U = new CAG_State(EpsilonClosureRes, ++m_nNextStateID);
unmarkedStates.push_back(U);
m_DFATable.push_back(U);
// Add transition from processingDFAState to new state on the current character
processingDFAState->AddTransition(*iter, U);
}
else
{
// This state already exists so add transition from
// processingState to already processed state
processingDFAState->AddTransition(*iter, s);
}
}
}
}
void CompileNfaToDfa( Context* con ) {
InitStateEdge( con );
//Node* n = DfaAddNode( con );
Node* n = new Node();
n->statelist = NULL;
n->edgelist = NULL;
n->next = NULL;
Node* t = con->nfa_stacktop->nfa->starts;
AddState( n, MakeDfaState( con, t->statelist->dummy ) );
EpsilonClosure( con, n, n->statelist );
PushDfaNode( con, n );
con->dfa = new Dfa();
con->dfa->next = NULL;
con->dfa->starts = n;
con->dfa->accepts = NULL;
DfaNodeElement* dne;
while ( ( dne = FirstUncoloredNode( con ) ) != NULL ) {
n = dne->node;
// test code
DfaNodeElement* _dne = con->dne_queue;
printf( "printf dne queue\n" );
while ( _dne != NULL ) {
Node *_n = _dne->node;
State* _ss = _n->statelist;
while ( _ss != NULL ) {
printf( "%d\t", _ss->dummy );
_ss = _ss->next;
}
printf( " colored:%d\n", _dne->colored );
_dne = _dne->next;
}
// test code end
dne->colored = true;
State* s = n->statelist;
Symbol* sym = con->symbollist;
Weight w;
while ( sym != NULL ) {
w = sym->symbol;
if ( w == EPSILON ) continue;
StateEdge* se = sequeue;
Node *nn = new Node();
nn->statelist = NULL;
nn->edgelist = NULL;
nn->next = NULL;
while ( se != NULL ) {
//printf( "%c", se->w );
if ( se->w == w ) {
// if find se->from in n->statelist;
bool found = false;
State* _s = n->statelist;
while ( _s != NULL ) {
if ( _s->dummy == se->from->dummy ) {
found = true;
break;
}
_s = _s->next;
}
if ( found ) {
AddState( nn, MakeDfaState( con, se->to->dummy ) );
}
}
se = se->next;
}
EpsilonClosure( con, nn, nn->statelist );
if ( nn->statelist == NULL ) {
delete nn;
}
else {
if ( FindDfaNode( con, nn ) == NULL ) {
PushDfaNode( con, nn );
}
else {
Node* temp = nn;
nn = FindDfaNode( con, nn );
State* prev, *next;
prev = next = temp->statelist;
while ( next != NULL ) {
prev = next;
next = next->next;
delete prev;
}
delete temp;
}
Edge* ee = new Edge();
ee->dest = nn;
ee->weight = w;
ee->next = n->edgelist;
n->edgelist = ee;
}
sym = sym->next;
}
}
dne = con->dne_queue;
while ( dne != NULL ) {
Node *_n = dne->node;
State* _ss = _n->statelist;
while ( _ss != NULL ) {
if ( _ss->dummy == con->nfa_stacktop->nfa->accepts->statelist->dummy ) {
_n->next = con->dfa->accepts;
con->dfa->accepts = _n;
break;
}
_ss = _ss->next;
}
dne = dne->next;
}
// test code
DfaNodeElement* _dne = con->dne_queue;
/*
printf( "printf dne queue\n" );
while ( _dne != NULL ) {
Node *_n = _dne->node;
State* _ss = _n->statelist;
while ( _ss != NULL ) {
printf( "%d\t", _ss->dummy );
_ss = _ss->next;
}
printf( " colored:%d\n", _dne->colored );
_dne = _dne->next;
}
*/
// test code end
DestoryStateEdge();
//DestoryContext( con );
}
