ltlcross: skip product that require too much acceptance sets

Reported by Fanda when he was testing ltl3dra 0.2.2.

* src/bin/ltlcross.cc: Here.
* src/tests/ltl3dra.test: New file.
* src/tests/Makefile.am: Add it.

src/bin/ltlcross.cc

@@ -737,6 +737,26 @@ namespace
 		   const spot::const_twa_graph_ptr& aut_j,
 		   size_t i, size_t j, bool icomp, bool jcomp)
   {
+    if (aut_i->num_sets() + aut_j->num_sets()
+	> 8 * sizeof(spot::acc_cond::mark_t::value_t))
+      {
+	// Report the skipped test if both automata are not
+	// complemented, or the --verbose option is used,
+	if (!verbose && (icomp || jcomp))
+	  return false;
+	std::cerr << "info: building ";
+	if (icomp)
+	  std::cerr << "Comp(N" << i << ')';
+	else
+	  std::cerr << 'P' << i;
+	if (jcomp)
+	  std::cerr << "*Comp(P" << j << ')';
+	else
+	  std::cerr << "*N" << j;
+	std::cerr << " requires more acceptance sets than supported\n";
+	return false;
+      }
+
     auto prod = spot::product(aut_i, aut_j);
 
     if (verbose)

src/tests/Makefile.am

@@ -215,6 +215,7 @@ TESTS_twa = \
   dra2dba.test \
   unambig.test \
   ltlcross4.test \
+  ltl3dra.test \
   ltl2dstar.test \
   ltl2dstar2.test \
   ltl2dstar3.test \

src/tests/ltl3dra.test

+#!/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/>.
+
+# Do some quick translations to make sure the neverclaims produced by
+# spot actually look correct!  We do that by parsing them via ltlcross.
+# ltl2neverclaim-lbtt.test does the same with LBTT if it is installed.
+
+. ./defs
+set -e
+
+# Skip this test if ltl3dra is not installed.
+(ltl3dra -v) || exit 77
+
+# This used to crash ltlcross because the number of
+# acceptance sets generated was to high.
+../../bin/ltlcross '../../bin/ltl2tgba' 'ltl3dra' -f '(<>((((p0) &&
+(!(<>(p2)))) || ((!(p0)) && (<>(p2)))) U ((<>(((p0) && (!([](((!(p1))
+&& ([](p3))) || ((p1) && (!([](p3)))))))) || ((!(p0)) && ([](((!(p1))
+&& ([](p3))) || ((p1) && (!([](p3))))))))) && (((p0) && (!(<>(p2))))
+|| ((!(p0)) && (<>(p2)))))))'