scc_filter: preserve state names and highlighted states

Suggested by Juraj Major.

* spot/twaalgos/sccfilter.cc: Here.
* tests/python/sccfilter.py: New file.
* tests/Makefile.am: Add it.
* NEWS: Mention the news.

NEWS

@@ -40,6 +40,8 @@ New in spot 2.1.2.dev (not yet released)
     this halves the run time of
        genltl --rv-counter=10 | ltl2tgba
 
+  * scc_filter() learned to preserve state names and highlighted states.
+
   Bugs:
 
   * ltl2tgba was alway using the highest settings for the LTL

spot/twaalgos/sccfilter.cc

@@ -330,10 +330,37 @@ namespace spot
       // has one initial state).
       auto init = inout[aut->get_init_state_number()];
       filtered->set_init_state(init < out_n ? init : filtered->new_state());
+
+      if (auto* names =
+          aut->get_named_prop<std::vector<std::string>>("state-names"))
+        {
+          std::cerr << "names\n";
+          unsigned size = names->size();
+          if (size > in_n)
+            size = in_n;
+          auto* new_names = new std::vector<std::string>(out_n);
+          filtered->set_named_prop("state-names", new_names);
+          for (unsigned s = 0; s < size; ++s)
+            {
+              unsigned new_s = inout[s];
+              if (new_s != -1U)
+                (*new_names)[new_s] = (*names)[s];
+            }
+        }
+      if (auto hs =
+          aut->get_named_prop<std::map<unsigned, unsigned>>("highlight-states"))
+        {
+          auto* new_hs = new std::map<unsigned, unsigned>;
+          filtered->set_named_prop("highlight-states", new_hs);
+          for (auto p: *hs)
+            {
+              unsigned new_s = inout[p.first];
+              if (new_s != -1U)
+                new_hs->emplace(new_s, p.second);
+            }
+        }
       return filtered;
     }
-
-
   }
 
   twa_graph_ptr

tests/Makefile.am

@@ -342,6 +342,7 @@ TESTS_python = \
   python/remfin.py \
   python/satmin.py \
   python/setacc.py \
+  python/sccfilter.py \
   python/setxor.py \
   python/trival.py \
   $(TESTS_ipython)

tests/python/sccfilter.py

@@ -0,0 +1,60 @@
+#!/usr/bin/python3
+# -*- mode: python; coding: utf-8 -*-
+# Copyright (C) 2016 Laboratoire de Recherche et Développement de
+# l'EPITA.
+#
+# 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/>.
+
+# Make sure scc_filter preserves state-names (suggested by Juraj
+# Major)
+
+import spot
+
+a = spot.automaton("""
+HOA: v1.1
+States: 3
+Start: 1
+AP: 1 "a"
+acc-name: Buchi
+Acceptance: 1 Inf(0)
+spot.highlight.states: 0 0 2 3
+--BODY--
+State: 0 "baz"
+[t] 0
+State: 2 "foo" {0}
+[0] 0
+[0] 2
+[!0] 2
+State: 1 "bar"
+[0] 2
+--END--
+""")
+
+assert (spot.scc_filter(a, True).to_str('hoa', '1.1') == """HOA: v1.1
+States: 2
+Start: 0
+AP: 1 "a"
+acc-name: Buchi
+Acceptance: 1 Inf(0)
+properties: trans-labels explicit-labels state-acc !complete
+properties: deterministic
+spot.highlight.states: 1 3
+--BODY--
+State: 0 "bar"
+[0] 1
+State: 1 "foo" {0}
+[t] 1
+--END--""")