spot/spot/misc/bddlt.hh
Maximilien Colange b86cbf0514 Mark bdd_hash as noexcept
* spot/misc/bddlt.hh: do it
2017-11-17 14:31:03 +01:00

94 lines
2.7 KiB
C++

// -*- coding: utf-8 -*-
// Copyright (C) 2011, 2014, 2017 Laboratoire de Recherche et
// Developpement de l'Epita (LRDE).
// Copyright (C) 2003, 2004 Laboratoire d'Informatique de Paris 6 (LIP6),
// département Systèmes Répartis Coopératifs (SRC), Université Pierre
// et Marie Curie.
//
// This file is part of Spot, a model checking library.
//
// Spot 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.
//
// Spot 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, see <http://www.gnu.org/licenses/>.
#pragma once
#include <bddx.h>
#include <functional>
namespace spot
{
/// \ingroup misc_tools
/// \brief Comparison functor for BDDs.
///
/// This comparison function use BDD ids for efficiency. An
/// algorithm depending on this order may return different results
/// depending on how the BDD library has been used before.
struct bdd_less_than :
public std::binary_function<const bdd&, const bdd&, bool>
{
bool
operator()(const bdd& left, const bdd& right) const
{
return left.id() < right.id();
}
};
/// \ingroup misc_tools
/// \brief Comparison functor for BDDs.
///
/// This comparison function actually check for BDD variables, so as
/// long as the variable order is the same, the output of this
/// comparison will be stable and independent on previous BDD
/// operations.
struct bdd_less_than_stable :
public std::binary_function<const bdd&, const bdd&, bool>
{
bool
operator()(const bdd& left, const bdd& right) const
{
int li = left.id();
int ri = right.id();
if (li == ri)
return false;
if (li <= 1 || ri <= 1)
return li < ri;
{
int vl = bdd_var(left);
int vr = bdd_var(right);
if (vl != vr)
return vl < vr;
}
// We check the high side before low, this way
// !a&b comes before a&!b and a&b
{
bdd hl = bdd_high(left);
bdd hr = bdd_high(right);
if (hl != hr)
return operator()(hl, hr);
return operator()(bdd_low(left), bdd_low(right));
}
}
};
/// \ingroup misc_tools
/// \brief Hash functor for BDDs.
struct bdd_hash :
public std::unary_function<const bdd&, size_t>
{
size_t
operator()(const bdd& b) const noexcept
{
return b.id();
}
};
}