/* CirKit: A circuit toolkit
 * Copyright (C) 2009-2015  University of Bremen
 * Copyright (C) 2015-2017  EPFL
 *
 * Permission is hereby granted, free of charge, to any person
 * obtaining a copy of this software and associated documentation
 * files (the "Software"), to deal in the Software without
 * restriction, including without limitation the rights to use,
 * copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following
 * conditions:
 *
 * The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
 * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
 * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
 * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 * OTHER DEALINGS IN THE SOFTWARE.
 */

#include "is_identity.hpp"

#include <boost/range/combine.hpp>
#include <boost/range/numeric.hpp>

#include <reversible/rcbdd.hpp>

namespace cirkit
{

bool is_identity( const circuit& circ )
{
  rcbdd mgr;
  mgr.initialize_manager();
  mgr.create_variables( circ.lines() );

  BDD f = mgr.create_from_circuit( circ );

  BDD identity = boost::accumulate( boost::combine( mgr.xs(), mgr.ys() ),
                                    mgr.manager().bddOne(),
                                    []( BDD current, const boost::tuple<BDD, BDD>& t ) {
                                      return current & ( boost::get<0>( t ).Xnor( boost::get<1>( t ) ) );
                                    } );

  return f == identity;
}

}

// Local Variables:
// c-basic-offset: 2
// eval: (c-set-offset 'substatement-open 0)
// eval: (c-set-offset 'innamespace 0)
// End:
