complete: Fix completion of automata using Fin-acceptance

* src/tgba/acc.cc, src/tgba/acc.hh: Add a way to extract
an unstatisfiable mark, and fix the eval() function for
Fin acceptance.
* src/tgbaalgos/complete.cc: Label the sink state using
an unsatisfiable mark.  Do not assume generalized Büchi.
* src/tgbatest/complete.test: New test.
* src/tgbatest/Makefile.am: Add it.

src/tgba/acc.cc

@@ -193,7 +193,7 @@ namespace spot
 	case acc_cond::acc_op::Inf:
 	  return (pos[-1].mark & inf) == pos[-1].mark;
 	case acc_cond::acc_op::Fin:
-	  return (pos[-1].mark & inf) == 0U;
+	  return (pos[-1].mark & inf) != pos[-1].mark;
 	case acc_cond::acc_op::FinNeg:
 	case acc_cond::acc_op::InfNeg:
 	  SPOT_UNREACHABLE();
@@ -413,6 +413,7 @@ namespace spot
 
     bdd_allocator ba;
     int base = ba.allocate_variables(c);
+    assert(base == 0);
     std::vector<bdd> r;
     std::vector<unsigned> sets(c);
     for (unsigned i = 0; r.size() < c; ++i)
@@ -483,6 +484,7 @@ namespace spot
 
     bdd_allocator ba;
     int base = ba.allocate_variables(c);
+    assert(base == 0);
     std::vector<bdd> r;
     std::vector<unsigned> sets(c);
     for (unsigned i = 0; r.size() < c; ++i)
@@ -543,6 +545,61 @@ namespace spot
     return rescode;
   }
 
+  std::pair<bool, acc_cond::mark_t>
+  acc_cond::acc_code::unsat_mark() const
+  {
+    if (empty())
+      return {false, 0U};
+
+    auto used = acc_cond::acc_code::used_sets();
+    unsigned c = used.count();
+
+    bdd_allocator ba;
+    int base = ba.allocate_variables(c);
+    assert(base == 0);
+    std::vector<bdd> r;
+    std::vector<unsigned> sets(c);
+    for (unsigned i = 0; r.size() < c; ++i)
+      {
+	if (used.has(i))
+	  {
+	    sets[base] = i;
+	    r.push_back(bdd_ithvar(base++));
+	  }
+	else
+	  {
+	    r.push_back(bddfalse);
+	  }
+      }
+
+    bdd res = to_bdd_rec(&back(), &r[0]);
+
+    if (res == bddtrue)
+      return {false, 0U};
+    if (res == bddfalse)
+      return {true, 0U};
+
+    bdd cube = bdd_satone(!res);
+    mark_t i = 0U;
+    while (cube != bddtrue)
+      {
+	// The acceptance set associated to this BDD variable
+	int s = sets[bdd_var(cube)];
+
+	bdd h = bdd_high(cube);
+	if (h == bddfalse)	// Negative variable? -> skip
+	  {
+	    cube = bdd_low(cube);
+	  }
+	else		// Positive variable? -> Inf
+	  {
+	    i.set(s);
+	    cube = h;
+	  }
+      }
+    return {true, i};
+  }
+
   bool acc_cond::acc_code::is_dnf() const
   {
     if (empty() || size() == 2)

src/tgba/acc.hh

@@ -659,6 +659,10 @@ namespace spot
       // Return the set of sets appearing in the condition.
       acc_cond::mark_t used_sets() const;
 
+      // Return (true, m) if there exist some m that does not satisfy
+      // the acceptance condition.  Return (false, 0U) otherwise.
+      std::pair<bool, acc_cond::mark_t> unsat_mark() const;
+
       // Return the sets used as Inf or Fin in the acceptance condition
       std::pair<acc_cond::mark_t, acc_cond::mark_t> used_inf_fin_sets() const;
 

src/tgbaalgos/complete.cc

@@ -25,21 +25,26 @@ namespace spot
   {
     unsigned n = aut->num_states();
     unsigned sink = -1U;
-    acc_cond::mark_t allacc = aut->acc().all_sets();
-    if (allacc == 0U)
+
+    // UM is a pair (bool, mark).  If the Boolean is false, the
+    // acceptance is always satisfiable.  Otherwise, MARK is an
+    // example of unsatisfiable mark.
+    auto um = aut->get_acceptance().unsat_mark();
+    if (!um.first)
       {
-	// We cannot safely complete an automaton if it has no
-	// acceptance set as the added sink would become accepting.
-	// In this case, add an acceptance set to all transitions.
-	allacc = aut->set_buchi();
+	// We cannot safely complete an automaton if its
+	// acceptance is always satisfiable.
+	auto acc = aut->set_buchi();
 	for (auto& t: aut->transition_vector())
-	  t.acc = allacc;
+	  t.acc = acc;
       }
     else
       {
-	// If some acceptance sets were used, loop over the states and
-	// seek a state that has only self loops, and that is not
-	// accepting.  This will be our sink state.
+	// Loop over the states and seek a state that has only self
+	// loops, and that is not accepting.  This will be our sink
+	// state.  Note that we do not even have to ensure that the
+	// state is complete as we will complete the whole automaton
+	// in a second pass.
 	for (unsigned i = 0; i < n; ++i)
 	  {
 	    bool selfloop = true;
@@ -53,8 +58,9 @@ namespace spot
 		  }
 		accsum |= t.acc;
 	      }
-	    if (selfloop && accsum != allacc) // We have found a sink!
+	    if (selfloop && !aut->acc().accepting(accsum))
 	      {
+		// We have found a sink!
 		sink = i;
 		break;
 	      }
@@ -63,7 +69,7 @@ namespace spot
 
     unsigned t = aut->num_transitions();
 
-    // Now complete all states (including the sink).
+    // Now complete all states (excluding any newly added the sink).
     for (unsigned i = 0; i < n; ++i)
       {
 	bdd missingcond = bddtrue;
@@ -94,7 +100,7 @@ namespace spot
 	    if (sink == -1U)
 	      {
 		sink = aut->new_state();
-		++n;
+		aut->new_transition(sink, sink, bddtrue, um.second);
 	      }
 	    // In case the automaton use state-based acceptance, propagate
 	    // the acceptance of the first transition to the one we add.

src/tgbatest/Makefile.am

@@ -72,6 +72,7 @@ TESTS = \
   det.test \
   neverclaimread.test \
   hoaparse.test \
+  complete.test \
   remfin.test \
   dstar.test \
   readsave.test \

src/tgbatest/complete.test

@@ -0,0 +1,117 @@
+#! /bin/sh
+# -*- coding: utf-8 -*-
+# Copyright (C) 2015 Laboratoire de Recherche et Développement de
+# l'Epita (LRDE).
+#
+# 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/>.
+
+
+. ./defs || exit 1
+
+set -e
+
+cat >automaton <<EOF
+HOA: v1
+States: 2
+Start: 0
+AP: 1 "a"
+Acceptance: 1 Fin(0)
+--BODY--
+State: 0
+[0] 1
+State: 1
+[0] 1
+--END--
+HOA: v1
+States: 2
+Start: 0
+AP: 1 "a"
+Acceptance: 2 t
+--BODY--
+State: 0
+[0] 1
+State: 1
+[0] 1
+--END--
+HOA: v1
+States: 2
+Start: 0
+AP: 1 "a"
+Acceptance: 0 f
+--BODY--
+State: 0
+[0] 1
+State: 1
+[0] 1
+--END--
+EOF
+
+cat >expected <<EOF
+HOA: v1
+States: 3
+Start: 0
+AP: 1 "a"
+Acceptance: 1 Fin(0)
+properties: trans-labels explicit-labels state-acc complete
+properties: deterministic
+--BODY--
+State: 0
+[0] 1
+[!0] 2
+State: 1
+[0] 1
+[!0] 2
+State: 2 {0}
+[t] 2
+--END--
+HOA: v1
+States: 3
+Start: 0
+AP: 1 "a"
+acc-name: Buchi
+Acceptance: 1 Inf(0)
+properties: trans-labels explicit-labels state-acc complete
+properties: deterministic
+--BODY--
+State: 0 {0}
+[0] 1
+[!0] 2
+State: 1 {0}
+[0] 1
+[!0] 2
+State: 2
+[t] 2
+--END--
+HOA: v1
+States: 2
+Start: 0
+AP: 1 "a"
+Acceptance: 0 f
+properties: trans-labels explicit-labels state-acc complete
+properties: deterministic
+--BODY--
+State: 0
+[0] 1
+[!0] 1
+State: 1
+[0] 1
+[!0] 1
+--END--
+EOF
+
+run 0 ../../bin/autfilt -CH automaton >out
+cat out
+diff out expected