030ebed367
* spot/twaalgos/genem.hh, spot/twaalgos/genem.cc (generic_emptiness_check_for_scc): Add a version that takes an acc. * spot/twaalgos/isweakscc.cc (scc_has_rejecting_cycle): Use generic_emptiness_check_for_scc.
114 lines
3.3 KiB
C++
114 lines
3.3 KiB
C++
// -*- coding: utf-8 -*-
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// Copyright (C) 2012-2019 Laboratoire de Recherche et Développement
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// de l'Epita (LRDE).
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//
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// This file is part of Spot, a model checking library.
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//
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// Spot is free software; you can redistribute it and/or modify it
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// under the terms of the GNU General Public License as published by
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// the Free Software Foundation; either version 3 of the License, or
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// (at your option) any later version.
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//
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// Spot is distributed in the hope that it will be useful, but WITHOUT
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// ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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// or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public
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// License for more details.
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//
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// You should have received a copy of the GNU General Public License
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// along with this program. If not, see <http://www.gnu.org/licenses/>.
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#include "config.h"
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#include <spot/tl/formula.hh>
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#include <spot/twaalgos/isweakscc.hh>
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#include <spot/twaalgos/genem.hh>
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namespace spot
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{
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namespace
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{
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[[noreturn]] static void
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invalid_scc_number(const char* fn)
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{
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throw std::invalid_argument(std::string(fn) + "(): invalid SCC number");
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}
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}
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bool
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scc_has_rejecting_cycle(scc_info& map, unsigned scc)
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{
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if (SPOT_UNLIKELY(scc >= map.scc_count()))
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invalid_scc_number("scc_has_rejecting_cycle");
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acc_cond neg_acc = map.get_aut()->get_acceptance().complement();
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return !generic_emptiness_check_for_scc(map, scc, neg_acc);
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}
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bool
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is_inherently_weak_scc(scc_info& map, unsigned scc)
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{
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if (SPOT_UNLIKELY(scc >= map.scc_count()))
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invalid_scc_number("is_inherently_weak_scc");
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// Weak SCCs are inherently weak.
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if (is_weak_scc(map, scc))
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return true;
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// If we reach this place, we now the SCC has an accepting cycle.
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// The question is now to find whether is also contains a
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// rejecting cycle.
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return !scc_has_rejecting_cycle(map, scc);
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}
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bool
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is_weak_scc(scc_info& map, unsigned scc)
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{
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if (SPOT_UNLIKELY(scc >= map.scc_count()))
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invalid_scc_number("is_weak_scc");
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// Rejecting SCCs are weak.
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if (map.is_rejecting_scc(scc))
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return true;
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// If all transitions use the same acceptance set, the SCC is weak.
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return map.marks_of(scc).size() == 1;
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}
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bool
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is_complete_scc(scc_info& map, unsigned scc)
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{
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if (SPOT_UNLIKELY(scc >= map.scc_count()))
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invalid_scc_number("is_complete_scc");
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auto a = map.get_aut();
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for (auto s: map.states_of(scc))
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{
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bool has_succ = false;
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bdd sumall = bddfalse;
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for (auto& t: a->out(s))
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{
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has_succ = true;
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bool in = true;
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for (auto d: a->univ_dests(t.dst))
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if (map.scc_of(d) != scc)
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{
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in = false;
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break;
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}
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if (!in)
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continue;
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sumall |= t.cond;
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if (sumall == bddtrue)
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break;
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}
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if (!has_succ || sumall != bddtrue)
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return false;
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}
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return true;
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}
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bool
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is_terminal_scc(scc_info& map, unsigned scc)
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{
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if (SPOT_UNLIKELY(scc >= map.scc_count()))
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invalid_scc_number("is_terminal_scc");
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// If all transitions use all acceptance conditions, the SCC is weak.
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return (map.is_accepting_scc(scc)
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&& map.marks_of(scc).size() == 1
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&& is_complete_scc(map, scc));
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}
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}
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