Add support for --check=strength

* src/twaalgos/strength.cc, src/twaalgos/strength.hh (check_strength):
New function.
* src/bin/common_aoutput.cc: Add --check=strength.
* src/tests/strength.test: New file.
* src/tests/Makefile.am: Add it.
* doc/org/hoa.org, NEWS: Document it.

NEWS

@@ -4,6 +4,12 @@ New in spot 1.99.5a (not yet released)
 
   * autfilt has two now filters: --is-weak and --is-terminal.
 
+  * All tools that output HOA files accept a --check=strength option
+    to request automata to be marked as "weak" or "terminal" as
+    appropriate.  Without this option, these properties may only be
+    set as a side-effect of running transformations that use this
+    information.
+
   Library:
 
   * Properties of automata (like the "properties:" line of the HOA

doc/org/hoa.org

@@ -591,8 +591,8 @@ particular:
 | =unambiguous=       | trusted | yes    | as stored if (=-Hv= or not =deterministic=) | can be re-checked with =--check=unambiguous=           |
 | =stutter-invariant= | trusted | yes    | as stored                                   | can be re-checked with =--check=stuttering=            |
 | =stutter-sensitive= | trusted | yes    | as stored                                   | can be re-checked with =--check=stuttering=            |
-| =terminal=          | trusted | yes    | as stored                                   |                                                        |
-| =weak=              | trusted | yes    | as stored if (=-Hv= or not =terminal=)      |                                                        |
+| =terminal=          | trusted | yes    | as stored                                   | can be re-checked with =--check=strength=              |
+| =weak=              | trusted | yes    | as stored if (=-Hv= or not =terminal=)      | can be re-checked with =--check=strength=              |
 | =inherently-weak=   | trusted | yes    | as stored if (=-Hv= or not =weak=)          |                                                        |
 | =colored=           | ignored | no     | checked                                     |                                                        |
 
@@ -867,6 +867,6 @@ When an automaton is output in HOA format, the =property:= lines
 includes property registered into the automaton (see the Property
 bits section above), and property that are trivial to compute.
 
-Command-line with a HOA output all have a =--check= option that can be
-used to request additional checks such as testing whether the
-automaton is stutter-invariant, or unambiguous.
+Command-line tools with a HOA output all have a =--check= option that
+can be used to request additional checks such as testing whether the
+automaton is stutter-invariant, unambiguous, weak, and terminal.

src/bin/common_aoutput.cc

@@ -33,6 +33,7 @@
 #include "twaalgos/neverclaim.hh"
 #include "twaalgos/stutter.hh"
 #include "twaalgos/isunamb.hh"
+#include "twaalgos/strength.hh"
 
 automaton_format_t automaton_format = Dot;
 static const char* opt_dot = nullptr;
@@ -46,6 +47,7 @@ enum check_type
   {
     check_unambiguous = (1 << 0),
     check_stutter = (1 << 1),
+    check_strength = (1 << 2),
     check_all = -1U,
   };
 static char const *const check_args[] =
@@ -54,6 +56,7 @@ static char const *const check_args[] =
     "stutter-invariant", "stuttering-invariant",
     "stutter-insensitive", "stuttering-insensitive",
     "stutter-sensitive", "stuttering-sensitive",
+    "strength", "weak", "terminal",
     "all",
     nullptr
   };
@@ -63,6 +66,7 @@ static check_type const check_types[] =
     check_stutter, check_stutter,
     check_stutter, check_stutter,
     check_stutter, check_stutter,
+    check_strength, check_strength, check_strength,
     check_all
   };
 ARGMATCH_VERIFY(check_args, check_types);
@@ -121,7 +125,8 @@ static const argp_option options[] =
     { "check", OPT_CHECK, "PROP", OPTION_ARG_OPTIONAL,
       "test for the additional property PROP and output the result "
       "in the HOA format (implies -H).  PROP may be any prefix of "
-      "'all' (default), 'unambiguous', or 'stutter-invariant'.", 0 },
+      "'all' (default), 'unambiguous', 'stutter-invariant', or 'strength'.",
+      0 },
     { nullptr, 0, nullptr, 0, nullptr, 0 }
   };
 
@@ -299,9 +304,11 @@ automaton_printer::print(const spot::twa_graph_ptr& aut,
   if (opt_check)
     {
       if (opt_check & check_stutter)
-	check_stutter_invariance(aut, f);
+	spot::check_stutter_invariance(aut, f);
       if (opt_check & check_unambiguous)
 	spot::check_unambiguous(aut);
+      if (opt_check & check_strength)
+	spot::check_strength(aut);
     }
 
   // Name the output automaton.

src/tests/Makefile.am

@@ -229,6 +229,7 @@ TESTS_twa = \
   uniq.test \
   sbacc.test \
   stutter-tgba.test \
+  strength.test \
   emptchk.test \
   emptchke.test \
   dfs.test \

src/tests/strength.test

+#!/bin/sh
+# -*- coding: utf-8 -*-
+# Copyright (C) 2015 Laboratoire de Recherche et Developpement
+# 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/>.
+
+. ./defs
+
+set -e
+
+autfilt=../../bin/autfilt
+
+cat >in <<EOF
+HOA: v1
+name: "a U b"
+States: 2
+Start: 1
+AP: 2 "a" "b"
+Acceptance: 1 Inf(0)
+--BODY--
+State: 0 {0}
+[t] 0
+State: 1
+[1] 0
+[0&!1] 1
+--END--
+HOA: v1
+States: 2
+Start: 1
+AP: 1 "a"
+Acceptance: 1 Inf(0)
+--BODY--
+State: 0 {0}
+[t] 1
+State: 1
+[0] 0 {0}
+[!0] 1 {0}
+--END--
+HOA: v1
+States: 2
+Start: 1
+AP: 1 "a"
+Acceptance: 2 Inf(0)|Inf(1)
+--BODY--
+State: 0 {0}
+[t] 1
+State: 1
+[0] 0 {1}
+[!0] 1 {0}
+--END--
+HOA: v1
+States: 2
+Start: 1
+Acceptance: 0 t
+--BODY--
+State: 0
+[t] 1
+State: 1
+[t] 0
+--END--
+HOA: v1
+States: 2
+Start: 1
+AP: 1 "a"
+Acceptance: 1 Inf(0)
+--BODY--
+State: 0 {0}
+[t] 1
+State: 1
+[!0] 1 {0}
+--END--
+EOF
+
+run 0 $autfilt -H --check=strength in | tee out
+
+cat >expected <<EOF
+HOA: v1
+name: "a U b"
+States: 2
+Start: 1
+AP: 2 "a" "b"
+acc-name: Buchi
+Acceptance: 1 Inf(0)
+properties: trans-labels explicit-labels state-acc deterministic
+properties: terminal
+--BODY--
+State: 0 {0}
+[t] 0
+State: 1
+[1] 0
+[0&!1] 1
+--END--
+HOA: v1
+States: 2
+Start: 1
+AP: 1 "a"
+acc-name: Buchi
+Acceptance: 1 Inf(0)
+properties: trans-labels explicit-labels state-acc colored complete
+properties: deterministic terminal
+--BODY--
+State: 0 {0}
+[t] 1
+State: 1 {0}
+[0] 0
+[!0] 1
+--END--
+HOA: v1
+States: 2
+Start: 1
+AP: 1 "a"
+Acceptance: 2 Inf(0) | Inf(1)
+properties: trans-labels explicit-labels trans-acc colored complete
+properties: deterministic
+--BODY--
+State: 0
+[t] 1 {0}
+State: 1
+[0] 0 {1}
+[!0] 1 {0}
+--END--
+HOA: v1
+States: 2
+Start: 1
+AP: 0
+acc-name: all
+Acceptance: 0 t
+properties: trans-labels explicit-labels state-acc complete
+properties: deterministic terminal
+--BODY--
+State: 0
+[t] 1
+State: 1
+[t] 0
+--END--
+HOA: v1
+States: 2
+Start: 1
+AP: 1 "a"
+acc-name: Buchi
+Acceptance: 1 Inf(0)
+properties: trans-labels explicit-labels state-acc colored
+properties: deterministic weak
+--BODY--
+State: 0 {0}
+[t] 1
+State: 1 {0}
+[!0] 1
+--END--
+EOF
+
+diff out expected

src/twaalgos/strength.cc

@@ -26,8 +26,8 @@ namespace spot
 {
   namespace
   {
-    template <bool terminal>
-    bool is_type_automaton(const const_twa_graph_ptr& aut, scc_info* si)
+    template <bool terminal, bool set = false>
+    bool is_type_automaton(const twa_graph_ptr& aut, scc_info* si)
     {
       // Create an scc_info if the user did not give one to us.
       bool need_si = !si;
@@ -35,7 +35,8 @@ namespace spot
 	si = new scc_info(aut);
       si->determine_unknown_acceptance();
 
-      bool result = true;
+      bool is_weak = true;
+      bool is_term = true;
       unsigned n = si->scc_count();
       for (unsigned i = 0; i < n; ++i)
 	{
@@ -54,33 +55,49 @@ namespace spot
 		    }
 		  else if (m != t.acc)
 		    {
-		      result = false;
+		      is_weak = false;
 		      goto exit;
 		    }
 		}
 	  if (terminal && si->is_accepting_scc(i) && !is_complete_scc(*si, i))
 	    {
-	      result = false;
-	      break;
+	      is_term = false;
+	      if (!set)
+		break;
 	    }
 	}
     exit:
       if (need_si)
 	delete si;
-      return result;
+      if (set)
+	{
+	  if (terminal)
+	    aut->prop_terminal(is_term && is_weak);
+	  aut->prop_weak(is_weak);
+	}
+      return is_weak && is_term;
     }
   }
 
   bool
   is_terminal_automaton(const const_twa_graph_ptr& aut, scc_info* si)
   {
-    return aut->prop_terminal() || is_type_automaton<true>(aut, si);
+    return (aut->prop_terminal() ||
+	    is_type_automaton<true>(std::const_pointer_cast<twa_graph>(aut),
+				    si));
   }
 
   bool
   is_weak_automaton(const const_twa_graph_ptr& aut, scc_info* si)
   {
-    return aut->prop_weak() || is_type_automaton<false>(aut, si);
+    return (aut->prop_weak() ||
+	    is_type_automaton<false>(std::const_pointer_cast<twa_graph>(aut),
+				     si));
+  }
+
+  void check_strength(const twa_graph_ptr& aut, scc_info* si)
+  {
+    is_type_automaton<true, true>(aut, si);
   }
 
   bool is_safety_mwdba(const const_twa_graph_ptr& aut)

src/twaalgos/strength.hh

@@ -58,4 +58,14 @@ namespace spot
   SPOT_API bool
   is_safety_mwdba(const const_twa_graph_ptr& aut);
 
+  /// \brief Whether an automaton is weak or terminal.
+  ///
+  /// This sets the "weak" and "terminal" property as appropriate.
+  ///
+  /// \param aut the automaton to check
+  ///
+  /// \param sm an scc_info object for the automaton if available (it
+  /// will be built otherwise).
+  SPOT_API void
+  check_strength(const twa_graph_ptr& aut, scc_info* sm = nullptr);
 }