algo: introduce remove unused states and symbols from a RHDPDA

alib2algo/src/automaton/simplify/RemoveUnused.cpp

+#include "RemoveUnused.h"
+#include <registration/AlgoRegistration.hpp>
+
+namespace {
+
+auto RenameRealTimeHeightDeterministicDPDA = registration::AbstractRegister < automaton::simplify::RemoveUnused, automaton::RealTimeHeightDeterministicDPDA < >, const automaton::RealTimeHeightDeterministicDPDA < > & > ( automaton::simplify::RemoveUnused::removeUnused, "automaton" ).setDocumentation (
+"Remove automaton's unused states and pushdown store or input symbols.\n\
+\n\
+@param automaton pushdown automaton to remove unused states and symbols from\n\
+@return @p automaton with removed states and symbols" );
+
+} /* namespace */

alib2algo/src/automaton/simplify/RemoveUnused.h

+/*
+ * 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 <alib/algorithm>
+#include <alib/iostream>
+#include <alib/map>
+#include <alib/vector>
+#include <sstream>
+
+#include <automaton/PDA/RealTimeHeightDeterministicDPDA.h>
+
+namespace automaton {
+
+namespace simplify {
+
+/**
+ * Removes unused states/symbols in an automaton's structures based on its transitions .
+ */
+class RemoveUnused {
+public:
+	/**
+	 * Removes unused automaton's states and pushdown store or input symbols.
+	 *
+	 * @tparam InputSymbolType Type for input symbols
+	 * @tparam PushdownStoreSymbolType Type of epsilon representation
+	 * @tparam StateType Type for states
+	 *
+	 * @param pda pushdown automaton to rename
+	 *
+	 * @return @p pda with renamed states and pushdown store symbols
+	 */
+	template < class InputSymbolType, class PushdownStoreSymbolType, class StateType >
+	static automaton::RealTimeHeightDeterministicDPDA < InputSymbolType, PushdownStoreSymbolType, StateType > removeUnused ( const automaton::RealTimeHeightDeterministicDPDA < InputSymbolType, PushdownStoreSymbolType, StateType > & pda );
+};
+
+template < class InputSymbolType, class PushdownStoreSymbolType, class StateType >
+automaton::RealTimeHeightDeterministicDPDA < InputSymbolType, PushdownStoreSymbolType, StateType > RemoveUnused::removeUnused ( const automaton::RealTimeHeightDeterministicDPDA < InputSymbolType, PushdownStoreSymbolType, StateType > & pda ) {
+	ext::set < InputSymbolType > alphabet;
+	ext::set < PushdownStoreSymbolType > pushdownAlphabet;
+	ext::set < StateType > states;
+
+	states.insert ( pda.getInitialState ( ) );
+	pushdownAlphabet.insert ( pda.getBottomOfTheStackSymbol ( ) );
+
+	for ( const auto & transition : pda.getCallTransitions ( ) ) {
+		if ( ! transition.first.second.is_epsilon ( ) )
+			alphabet.insert ( transition.first.second.getSymbol ( ) );
+		pushdownAlphabet.insert ( transition.second.second );
+		states.insert ( transition.first.first );
+		states.insert ( transition.second.first );
+	}
+
+	for ( const auto & transition : pda.getLocalTransitions ( ) ) {
+		if ( ! transition.first.second.is_epsilon ( ) )
+			alphabet.insert ( transition.first.second.getSymbol ( ) );
+		states.insert ( transition.first.first );
+		states.insert ( transition.second );
+	}
+
+	for ( const auto & transition : pda.getReturnTransitions ( ) ) {
+		if ( ! std::get < 1 > ( transition.first ).is_epsilon ( ) )
+			alphabet.insert ( std::get < 1 > ( transition.first ).getSymbol ( ) );
+		pushdownAlphabet.insert ( std::get < 2 > ( transition.first ) );
+		states.insert ( std::get < 0 > ( transition.first ) );
+		states.insert ( transition.second );
+	}
+
+	automaton::RealTimeHeightDeterministicDPDA < InputSymbolType, PushdownStoreSymbolType, StateType > result ( pda.getInitialState ( ), pda.getBottomOfTheStackSymbol ( ) );
+
+	result.setInputAlphabet ( alphabet );
+	result.setPushdownStoreAlphabet ( pushdownAlphabet );
+	result.setStates ( states );
+
+	for ( const StateType & state : pda.getFinalStates ( ) )
+		if ( states.contains ( state ) )
+			result.addFinalState ( state );
+
+	for ( const auto & transition : pda.getCallTransitions ( ) )
+		result.addCallTransition ( transition.first.first, transition.first.second, transition.second.first, transition.second.second );
+
+	for ( const auto & transition : pda.getLocalTransitions ( ) )
+		result.addLocalTransition ( transition.first.first, transition.first.second, transition.second );
+
+	for ( const auto & transition : pda.getReturnTransitions ( ) )
+		result.addReturnTransition ( std::get < 0 > ( transition.first ), std::get < 1 > ( transition.first ), std::get < 2 > ( transition.first ), transition.second );
+
+	return result;
+}
+
+} /* namespace simplify */
+
+} /* namespace automaton */
+