EpsilonClosure.h

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/*
 * This file is part of Algorithms library toolkit.
 * Copyright (C) 2017 Jan Travnicek (jan.travnicek@fit.cvut.cz)
 
 * Algorithms library toolkit is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 
 * Algorithms library toolkit is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 
 * You should have received a copy of the GNU General Public License
 * along with Algorithms library toolkit.  If not, see <http://www.gnu.org/licenses/>.
 */
 
#pragma once
 
#include <queue>
 
#include <ext/algorithm>
 
#include <alib/set>
#include <alib/map>
 
#include <automaton/FSM/ExtendedNFA.h>
#include <automaton/FSM/CompactNFA.h>
#include <automaton/FSM/EpsilonNFA.h>
#include <automaton/FSM/MultiInitialStateNFA.h>
#include <automaton/FSM/NFA.h>
#include <automaton/FSM/DFA.h>
#include <automaton/TA/EpsilonNFTA.h>
 
#include <regexp/properties/RegExpEpsilon.h>
 
namespace automaton {
 
namespace properties {
 
class EpsilonClosure {
public:
    template < class SymbolType, class StateType >
    static ext::set<StateType> epsilonClosure( const automaton::EpsilonNFA < SymbolType, StateType > & fsm, const StateType & q );
 
    template < class SymbolType, class StateType >
    static ext::set<StateType> epsilonClosure( const automaton::EpsilonNFTA < SymbolType, StateType > & fta, const StateType & q );
 
    template < class T >
    requires isDFA < T > || isNFA < T > || isMultiInitialStateNFA < T >
    static ext::set < typename T::StateType > epsilonClosure ( const T & fsm, const typename T::StateType & q );
 
    template < class SymbolType, class StateType >
    static ext::set<StateType> epsilonClosure( const automaton::ExtendedNFA < SymbolType, StateType > & fsm, const StateType & q );
 
    template < class SymbolType, class StateType >
    static ext::set<StateType> epsilonClosure( const automaton::CompactNFA < SymbolType, StateType > & fsm, const StateType & q );
};
 
template < class SymbolType, class StateType >
ext::set<StateType> EpsilonClosure::epsilonClosure( const automaton::EpsilonNFA < SymbolType, StateType > & fsm, const StateType & q ) {
    if ( ! fsm.getStates ( ).contains ( q ) )
        throw exception::CommonException ( "State is not in the automaton" );
 
    ext::set < StateType > closure { q };
    std::queue < StateType > queue;
    queue.push ( q );
 
    while ( ! queue.empty( ) ) {
        StateType p = std::move ( queue.front ( ) );
        queue.pop ( );
 
        auto tos = fsm.getTransitions ( ).equal_range ( ext::make_pair ( p, common::symbol_or_epsilon < SymbolType > ( ) ) );
        for ( const auto & transition : tos )
            if ( closure.insert ( transition.second ).second )
                queue.push ( transition.second );
    }
 
    return closure;
}
 
template < class SymbolType, class StateType >
ext::set < StateType > EpsilonClosure::epsilonClosure( const automaton::EpsilonNFTA < SymbolType, StateType > & fta, const StateType & q ) {
    if ( ! fta.getStates ( ).contains ( q ) )
        throw exception::CommonException ( "State is not in the automaton" );
 
    ext::set < StateType > closure { q };
    std::queue < StateType > queue;
    queue.push ( q );
 
    while ( ! queue.empty ( ) ) {
        StateType p = std::move ( queue.front ( ) );
        queue.pop ( );
 
        auto tos = fta.getTransitions ( ).equal_range ( p );
        for ( const auto & transition : tos )
            if ( closure.insert ( transition.second ).second )
                queue.push ( transition.second );
    }
 
    return closure;
}
 
template < class T >
requires isDFA < T > || isNFA < T > || isMultiInitialStateNFA < T >
ext::set < typename T::StateType > EpsilonClosure::epsilonClosure ( const T & fsm, const typename T::StateType & q ) {
    if ( ! fsm.getStates ( ).contains ( q ) )
        throw exception::CommonException ( "State is not in the automaton" );
 
    return { q };
}
 
template < class SymbolType, class StateType >
ext::set<StateType> EpsilonClosure::epsilonClosure( const automaton::ExtendedNFA < SymbolType, StateType > & fsm, const StateType & q ) {
    if ( ! fsm.getStates ( ).contains ( q ) )
        throw exception::CommonException("State is not in the automaton");
 
    ext::set < StateType > closure { q };
    std::queue < StateType > queue;
 
    queue.push ( q );
    while ( ! queue.empty( ) ) {
        StateType p = std::move ( queue.front ( ) );
        queue.pop ( );
 
        for ( const auto & transition : fsm.getTransitionsFromState ( p ) )
            if ( regexp::properties::RegExpEpsilon::languageContainsEpsilon ( transition.first.second ) )
                if ( closure.insert ( transition.second ).second )
                    queue.push ( transition.second );
    }
 
    return closure;
}
 
template < class SymbolType, class StateType >
ext::set<StateType> EpsilonClosure::epsilonClosure( const automaton::CompactNFA < SymbolType, StateType > & fsm, const StateType & q ) {
    if ( ! fsm.getStates ( ).contains ( q ) )
        throw exception::CommonException ("State is not in the automaton");
 
    ext::set < StateType > closure { q };
    std::queue < StateType > queue;
 
    queue.push ( q );
    while ( ! queue.empty ( ) ) {
        StateType p = std::move ( queue.front ( ) );
        queue.pop ( );
 
        for ( const auto & transition : fsm.getTransitionsFromState ( p ) )
            if ( transition.first.second.empty ( ) )
                if ( closure.insert ( transition.second ).second )
                    queue.push ( transition.second );
    }
 
    return closure;
}
 
} /* namespace properties */
 
} /* namespace automaton */