NFAStateSet operationCONCAT ( NFAStateSet a, NFAStateSet b )
{
/*
* CONCATs the states pointed by a and b, and then returns the NFA for
* a@b
*/
NFAStateSet output;
for ( unsigned int i=0; i<a.size() && a[i][0] != -1; i++ )
output.push_back( a[i] );
for ( unsigned int i=0; i<b.size() && b[i][0] != -1; i++ )
output.push_back( b[i] );
int oldStart1;
int oldStart2;
int oldFinish1;
int oldFinish2;
if ( a[a.size()-1][0] == -1 ){
oldStart1 = a[a.size()-1][1];
oldFinish1 = a[a.size()-1][2];
}
else{
oldStart1 = a[0][1];
oldFinish1 = a[0][2];
}
if ( b[b.size()-1][0] == -1 ){
oldStart2 = b[b.size()-1][1];
oldFinish2 = b[b.size()-1][2];
}
else {
oldStart2 = b[0][1];
oldFinish2 = b[0][2];
}
int newStart = uniqueStateID;
vector<int> startEpsilon, middleEpsilon;
startEpsilon.push_back ( operators[EPSILON] );
startEpsilon.push_back ( newStart );
startEpsilon.push_back ( oldStart1 );
middleEpsilon.push_back ( operators[EPSILON] );
middleEpsilon.push_back ( oldFinish1 );
middleEpsilon.push_back ( oldStart2 );
uniqueStateID++;
int newFinal = uniqueStateID;
vector<int> finalEpsilon;
finalEpsilon.push_back ( operators[EPSILON] );
finalEpsilon.push_back ( oldFinish2 );
finalEpsilon.push_back ( newFinal );
uniqueStateID++;
vector<int> startEndInfo;
startEndInfo.push_back( -1 );
startEndInfo.push_back( newStart );
startEndInfo.push_back( newFinal );
output.push_back ( startEpsilon );
output.push_back ( middleEpsilon );
output.push_back ( finalEpsilon );
output.push_back ( startEndInfo );
return output;
}
NFAStateSet allTermStates ( string fileName )
{
ifstream fpCal;
fpCal.open( strdup(fileName.c_str()) );
if (!fpCal.is_open()){
perror("Regular expression file doesn't exist or could not be opened\n");
exit (1);
}
string terminalString;
NFAStateSet singletonStates;
getline (fpCal,terminalString );
stringstream ss(terminalString); // Insert the string into a stream
/*
* Push the EPSILON state first as state 1->2 on EPSILON
*/
vector <int> epsilonState;
epsilonState.push_back( (int)operators[EPSILON] );
epsilonState.push_back( -1 );
epsilonState.push_back( -1 );
singletonStates.push_back(epsilonState);
/*
* Now do the same for all other terminals
*/
while (ss){
string sub;
ss >> sub;
vector <int> inputState;
inputState.push_back((int)(sub.c_str())[0]);
inputState.push_back(-1);
inputState.push_back(-1);
singletonStates.push_back(inputState);
}
singletonStates.pop_back();
fpCal.close();
return singletonStates;
}
NFAStateSet combineAllNFA ( vector < NFAStateSet> allRegexNFA )
{
NFAStateSet combined;
for ( unsigned int i=0; i<allRegexNFA.size(); i++){
for ( unsigned int j=0; j<allRegexNFA[i].size(); j++){
if ( allRegexNFA[i][j][0] != -1 )
combined.push_back(allRegexNFA[i][j]);
if ( allRegexNFA[i][j][0] == -1 ){
vector <int> temp;
temp.push_back( (int)operators[EPSILON] );
temp.push_back( 0 );
temp.push_back( allRegexNFA[i][j][1] );
combined.push_back ( temp );
vector <int> startEndInfo;
startEndInfo.push_back( -1 );
startEndInfo.push_back( 0 );
startEndInfo.push_back( allRegexNFA[i][j][2] );
combined.push_back ( startEndInfo );
}
}
}
return combined;
}
NFAStateSet operationSTAR ( NFAStateSet a )
{
/*
* CONCATs the states pointed by a and b, and then returns the NFA for
* a*
*/
NFAStateSet output;
for ( unsigned int i=0; i<a.size() && a[i][0] != -1; i++ )
output.push_back( a[i] );
int oldStart;
int oldFinish;
if ( a[a.size()-1][0] == -1 ){
oldStart = a[a.size()-1][1];
oldFinish = a[a.size()-1][2];
}
else{
oldStart = a[0][1];
oldFinish = a[0][2];
}
int newStart = uniqueStateID;
uniqueStateID++;
int newFinal = uniqueStateID;
uniqueStateID++;
vector<int> startEpsilon, startFinishEpsilon;
startEpsilon.push_back ( operators[EPSILON] );
startEpsilon.push_back ( newStart );
startEpsilon.push_back ( oldStart );
startFinishEpsilon.push_back ( operators[EPSILON] );
startFinishEpsilon.push_back ( newStart );
startFinishEpsilon.push_back ( newFinal );
vector<int> loopBack, finishEpsilon;
loopBack.push_back ( operators[EPSILON] );
loopBack.push_back ( oldFinish );
loopBack.push_back ( oldStart );
finishEpsilon.push_back ( operators[EPSILON] );
finishEpsilon.push_back ( oldFinish );
finishEpsilon.push_back ( newFinal );
vector<int> startEndInfo;
startEndInfo.push_back( -1 );
startEndInfo.push_back( newStart );
startEndInfo.push_back( newFinal );
output.push_back ( startEpsilon );
output.push_back ( startFinishEpsilon );
output.push_back ( loopBack );
output.push_back ( finishEpsilon );
output.push_back ( startEndInfo );
return output;
}
NFAStateSet generateOpStack ( string postfix, string fileName )
{
stack < NFAStateSet > stateStack;
NFAStateSet inputState = allTermStates( fileName );
bool isSingleton = true;
for ( unsigned int i=0; i<postfix.length(); i++ ){
if ( isOperator( postfix[i] ) == -1 ){
//use the nfa for this state
for ( unsigned int j = 0; j<inputState.size(); j++ ){
if ( inputState[j][0] == (int)postfix[i] ){
NFAStateSet tempToBePushed;
/*
* Copy this to uidGiven to assign unique IDs
*/
vector <int> uidGiven = inputState[j];
uidGiven[1]=uniqueStateID;
uniqueStateID++;
uidGiven[2]=uniqueStateID;
uniqueStateID++;
tempToBePushed.push_back(uidGiven);
stateStack.push ( tempToBePushed );
break;
}
}
}
if ( isOperator ( postfix[i] ) == OR ){
//send the two preceding states to the function to OR
NFAStateSet output;
NFAStateSet operand2 = stateStack.top();
stateStack.pop();
NFAStateSet operand1 = stateStack.top();
stateStack.pop();
output = operationOR ( operand1, operand2 );
stateStack.push(output);
isSingleton = false;
}
if ( isOperator ( postfix[i] ) == CONCAT ){
//send the two preceding states to the function to CONCAT
NFAStateSet output;
NFAStateSet operand2 = stateStack.top();
stateStack.pop();
NFAStateSet operand1 = stateStack.top();
stateStack.pop();
output = operationCONCAT ( operand1, operand2 );
stateStack.push(output);
isSingleton = false;
}
if ( isOperator ( postfix[i] ) == STAR ){
//send the preceding state to the function to STAR
NFAStateSet output;
NFAStateSet operand = stateStack.top();
stateStack.pop();
output = operationSTAR ( operand );
stateStack.push(output);
isSingleton = false;
}
}
if (!isSingleton){
NFAStateSet finalStateSet = stateStack.top();
if (!stateStack.empty())
stateStack.pop();
if (stateStack.empty())
return finalStateSet;
else{
cout<<"ERROR: NFA stack didn't empty itself\n";
exit(1);
}
}
else if ( isSingleton ){
NFAStateSet finalStateSet = stateStack.top();
vector <int> startEndInfo;
startEndInfo.push_back(-1);
startEndInfo.push_back(finalStateSet[0][1]);
startEndInfo.push_back(finalStateSet[0][2]);
finalStateSet.push_back( startEndInfo );
if (!stateStack.empty())
stateStack.pop();
if ( stateStack.empty() )
return finalStateSet;
else{
cout<<"ERROR: Stack didn't empty itself\n";
exit(1);
}
}
NFAStateSet dummyReturnVal;
return (dummyReturnVal);
}
