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****************************************************************************/

#ifndef NFA_H

#define NFA_H

#include <QMap>

#include <QHash>

#include <QString>

#include <QVector>

#include <QDebug>

#include <QStack>

#include <QByteArray>

#include "global.h"

typedef QHash<InputType, int> TransitionMap;

struct State

{

    QString symbol;

    TransitionMap transitions;

};

inline QDataStream &operator<<(QDataStream &stream, const State &state)

{

    return stream << state.symbol << state.transitions;

}

inline QDataStream &operator>>(QDataStream &stream, State &state)

{

    return stream >> state.symbol >> state.transitions;

}

struct DFA : public QVector<State>

{

    void debug() const;

    DFA minimize() const;

};

class NFA

{

public:

    static NFA createSingleInputNFA(InputType input);

    static NFA createSymbolNFA(const QString &symbol);

    static NFA createAlternatingNFA(const NFA &a, const NFA &b);

    static NFA createConcatenatingNFA(const NFA &a, const NFA &b);

    static NFA createOptionalNFA(const NFA &a);

    // convenience

    static NFA createStringNFA(const QByteArray &str);

    static NFA createSetNFA(const QSet<InputType> &set);

    static NFA createZeroOrOneNFA(const NFA &a);

    static NFA applyQuantity(const NFA &a, int minOccurrences, int maxOccurrences);

    void setTerminationSymbol(const QString &symbol);

    DFA toDFA() const;

    inline bool isEmpty() const { return states.isEmpty(); }

    inline int stateCount() const { return states.count(); }

    void debug();

private:

    void initialize(int size);

    void addTransition(int from, InputType input, int to);

    void copyFrom(const NFA &other, int baseState);

    void initializeFromPair(const NFA &a, const NFA &b,

                            int *initialA, int *finalA,

                            int *initialB, int *finalB);

    QSet<int> epsilonClosure(const QSet<int> &initialClosure) const;

    inline void assertValidState(int state)

    { Q_UNUSED(state); Q_ASSERT(state >= 0); Q_ASSERT(state < states.count()); }

#if defined(AUTOTEST)

public:

#endif

    int initialState;

    int finalState;

    QVector<State> states;

};

#endif // NFA_H