code: /*
   * This file is part of a Java port of the program ltl2dstar
   * (http://www.ltl2dstar.de/) for PRISM (http://www.prismmodelchecker.org/)
   * Copyright (C) 2005-2007 Joachim Klein <j.klein@ltl2dstar.de>
   * Copyright (c) 2007 Carlos Bederian
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License version 2 as 
   *  published by the Free Software Foundation.
   *
   * This program 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 this program; if not, write to the Free Software
   * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
   */
  
  package jltl2dstar;
  
  import jltl2ba.APSet;
  import jltl2ba.SimpleLTL;
  import jltl2ba.SimpleLTL.LTLType;
  import prism.PrismException;
  
  public class LTL2DRA {
  
  	private Options_Safra _safra_opt;
  
  	public LTL2DRA(Options_Safra safra_opt) {
  		_safra_opt = safra_opt;
  	}
  
  	/**
  	 * Convert an LTL formula to a DRA.
  	 * @param ltl the LTL formula
  	 * @param options which operators are allowed
  	 * @return a shared_ptr to the DRA
  	 */
  	private DRA LTLtoDRA_rec(SimpleLTL ltl, APSet apset, Options_LTL2DRA options) throws PrismException
  	{
  		SimpleLTL ltl_pnf = ((SimpleLTL)ltl.clone()).simplify();
  		
  		if (options.allow_union && ltl_pnf.kind == LTLType.OR) {
  			SimpleLTL ltl_left = ltl_pnf.left;
  			SimpleLTL ltl_right = ltl_pnf.right;
  
  			Options_LTL2DRA rec_opt = options.clone();
  			rec_opt.recursion();
  
  			DRA dra_left = LTLtoDRA_rec(ltl_left, apset, rec_opt);
  			DRA dra_right = LTLtoDRA_rec(ltl_right, apset, rec_opt);
  
  			return dra_left.calculateUnion(dra_right, options.opt_safra.union_trueloop, options.detailed_states);
  		}
  
  		/*  if (options.safety) {
  	    LTLSafetyAutomata lsa;
  
  	    DRA_ptr safety_dra(lsa.ltl2dra<DRA_t>(ltl,
  						  options.scheck_path));
  
  	    if (safety_dra.get()!=0) {
  	      return safety_dra;
  	    }
  	  	}
  		 */  
  		NBA nba = ltl_pnf.toNBA(apset);
  
  		if (nba == null) {
  			throw new PrismException("Couldn't create NBA from LTL formula");
  		}
  
  		NBA2DRA nba2dra = new NBA2DRA(options.opt_safra, false);
  
  		DRA dra = nba2dra.convert(nba, 0);
  
  		if (options.optimizeAcceptance) {
  			dra.optimizeAcceptanceCondition();
  		}
  
  		if (options.bisim) {
  			DRAOptimizations dra_optimizer = new DRAOptimizations();
  			dra = dra_optimizer.optimizeBisimulation(dra, false, false, false);
  		}
  
  		return dra;
  
  	}
  
  	/* public DRA LTLtoDRA(SimpleLTL ltl, Options_LTL2DRA options) throws PrismException {
  		return LTLtoDRA_rec(ltl, ltl.getAPs(), options);
  	} */
  	
  	public DRA LTLtoDRA(SimpleLTL ltl, APSet apset, Options_LTL2DRA options) throws PrismException {
  		return LTLtoDRA_rec(ltl, apset, options);
  	}
  
  
  
  	/**
  	 * Convert an NBA to a DRA using Safra's algorithm.
  	 * If limit is specified (>0), the conversion is 
  	 * aborted with LimitReachedException when the number of 
  	 * states exceeds the limit.
  	 * @param nba the formula
  	 * @param limit a limit on the number of states (0 for no limit)
  	 * @param detailedStates save detailed interal information (Safra trees) 
  	 *                       in the generated states
  	 * @param stutter_information Information about the symbols that can be stuttered
  	 * @return a shared_ptr to the created DRA
  	 */
  	// DRA nba2dra(NBA nba, int limit, boolean detailedStates, StutterSensitivenessInformation::ptr stutter_information) {
  	DRA nba2dra(NBA nba, int limit, boolean detailedStates) throws PrismException {
  
  		DRA dra = null;
  		NBA2DRA nba2dra = new NBA2DRA(_safra_opt, detailedStates);
  
  		try {
  			dra = nba2dra.convert(nba, limit);
  		} catch (PrismException e) {
  			dra = null;
  			// rethrow to notify caller
  			throw e;
  		}
  		return dra;  
  	}
  
  
  	/** Get the options for Safra's algorithm */
  	public Options_Safra getOptions() {
  		return _safra_opt;
  	}
  
  }
  