qxsdstatemachine_p.h

Go to the documentation of this file.

/****************************************************************************
**
** Copyright (C) 2014 Digia Plc and/or its subsidiary(-ies).
** Contact: http://www.qt-project.org/legal
**
** This file is part of the QtXmlPatterns module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
** Commercial License Usage
** Licensees holding valid commercial Qt licenses may use this file in
** accordance with the commercial license agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and Digia.  For licensing terms and
** conditions see http://qt.digia.com/licensing.  For further information
** use the contact form at http://qt.digia.com/contact-us.
**
** GNU Lesser General Public License Usage
** Alternatively, this file may be used under the terms of the GNU Lesser
** General Public License version 2.1 as published by the Free Software
** Foundation and appearing in the file LICENSE.LGPL included in the
** packaging of this file.  Please review the following information to
** ensure the GNU Lesser General Public License version 2.1 requirements
** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
**
** In addition, as a special exception, Digia gives you certain additional
** rights.  These rights are described in the Digia Qt LGPL Exception
** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
**
** GNU General Public License Usage
** Alternatively, this file may be used under the terms of the GNU
** General Public License version 3.0 as published by the Free Software
** Foundation and appearing in the file LICENSE.GPL included in the
** packaging of this file.  Please review the following information to
** ensure the GNU General Public License version 3.0 requirements will be
** met: http://www.gnu.org/copyleft/gpl.html.
**
**
** $QT_END_LICENSE$
**
****************************************************************************/

//
//  W A R N I N G
//  -------------
//
// This file is not part of the Qt API.  It exists purely as an
// implementation detail.  This header file may change from version to
// version without notice, or even be removed.
//
// We mean it.

#ifndef Patternist_XsdStateMachine_H
#define Patternist_XsdStateMachine_H

#include "qnamepool_p.h"

#include <QtCore/QHash>
#include <QtCore/QSet>
#include <QtCore/QTextStream>

class QIODevice;

QT_BEGIN_HEADER

QT_BEGIN_NAMESPACE

namespace QPatternist
{
    template <typename TransitionType>
    class XsdStateMachine
    {
        public:
            typedef qint32 StateId;

            enum StateType
            {
                StartState,     
                StartEndState,  
                InternalState,  
                EndState        
            };

            XsdStateMachine();

            XsdStateMachine(const NamePool::Ptr &namePool);

            StateId addState(StateType type);

            void addTransition(StateId start, TransitionType transition, StateId end);

            void addEpsilonTransition(StateId start, StateId end);

            void reset();

            void clear();

            bool proceed(TransitionType transition);

            QList<TransitionType> possibleTransitions() const;

            template <typename InputType>
            bool proceed(InputType input);

            template <typename InputType>
            bool inputEqualsTransition(InputType input, TransitionType transition) const;

            bool inEndState() const;

            TransitionType lastTransition() const;

            StateId startState() const;

            QString transitionTypeToString(TransitionType type) const;

            bool outputGraph(QIODevice *device, const QString &graphName) const;

            XsdStateMachine<TransitionType> toDFA() const;

            QHash<StateId, StateType> states() const;

            QHash<StateId, QHash<TransitionType, QVector<StateId> > > transitions() const
            {
                return m_transitions;
            }

        private:
            StateId dfaStateForNfaState(QSet<StateId> nfaState, QList< QPair< QSet<StateId>, StateId> > &stateTable, XsdStateMachine<TransitionType> &dfa) const;

            QSet<StateId> epsilonClosure(const QSet<StateId> &input) const
            {
                // every state can reach itself by epsilon transition, so include the input states
                // in the result as well
                QSet<StateId> result = input;

                // add the input states to the list of to be processed states
                QList<StateId> workStates = input.toList();
                while (!workStates.isEmpty()) { // while there are states to be processed left...

                    // dequeue one state from list
                    const StateId state = workStates.takeFirst();

                    // get the list of states that can be reached by the epsilon transition
                    // from the current 'state'
                    const QVector<StateId> targetStates = m_epsilonTransitions.value(state);
                    for (int i = 0; i < targetStates.count(); ++i) {
                        // if we have this target state not in our result set yet...
                        if (!result.contains(targetStates.at(i))) {
                            // ... add it to the result set
                            result.insert(targetStates.at(i));

                            // add the target state to the list of to be processed states as well,
                            // as we want to have the epsilon transitions not only for the first
                            // level of following states
                            workStates.append(targetStates.at(i));
                        }
                    }
                }

                return result;
            }

            QSet<StateId> move(const QSet<StateId> &states, TransitionType input) const
            {
                QSet<StateId> result;

                QSetIterator<StateId> it(states);
                while (it.hasNext()) { // iterate over all given states
                    const StateId state = it.next();

                    // get the transition table for the current state
                    const QHash<TransitionType, QVector<StateId> > transitions = m_transitions.value(state);

                    // get the target states for the given input
                    const QVector<StateId> targetStates = transitions.value(input);

                    // add all target states to the result
                    for (int i = 0; i < targetStates.size(); ++i)
                        result.insert(targetStates.at(i));
                }

                return result;
            }

            NamePool::Ptr                                             m_namePool;
            QHash<StateId, StateType>                                 m_states;
            QHash<StateId, QHash<TransitionType, QVector<StateId> > > m_transitions;
            QHash<StateId, QVector<StateId> >                         m_epsilonTransitions;
            StateId                                                   m_currentState;
            qint32                                                    m_counter;
            TransitionType                                            m_lastTransition;
    };

    #include "qxsdstatemachine.cpp"
}

QT_END_NAMESPACE

QT_END_HEADER

#endif