Add a cleanup_acceptance() algorithm

* src/tgbaalgos/cleanacc.cc, src/tgbaalgos/cleanacc.hh: New file.
* src/tgbaalgos/Makefile.am: Add them.
* src/tgba/acc.hh, src/tgba/tgba.hh (get_acceptance): Return a
reference.
* src/bin/autfilt.cc: Add a --cleanup-acceptance option.
* src/tgbatest/hoaparse.test: Test it.

src/bin/autfilt.cc

@@ -50,6 +50,7 @@
 #include "tgbaalgos/sbacc.hh"
 #include "tgbaalgos/stripacc.hh"
 #include "tgbaalgos/remfin.hh"
+#include "tgbaalgos/cleanacc.hh"
 
 
 static const char argp_program_doc[] ="\
@@ -82,6 +83,7 @@ Exit status:\n\
 #define OPT_KEEP_STATES 20
 #define OPT_DNF_ACC 21
 #define OPT_REM_FIN 22
+#define OPT_CLEAN_ACC 23
 
 static const argp_option options[] =
   {
@@ -125,6 +127,8 @@ static const argp_option options[] =
       "put the acceptance condition in Disjunctive Normal Form", 0 },
     { "remove-fin", OPT_REM_FIN, 0, 0,
       "rewrite the automaton without using Fin acceptance", 0 },
+    { "cleanup-acceptance", OPT_CLEAN_ACC, 0, 0,
+      "remove unused acceptance sets from the automaton", 0 },
     /**************************************************/
     { 0, 0, 0, 0, "Filtering options:", 6 },
     { "are-isomorphic", OPT_ARE_ISOMORPHIC, "FILENAME", 0,
@@ -206,6 +210,7 @@ static bool opt_sbacc = false;
 static bool opt_stripacc = false;
 static bool opt_dnf_acc = false;
 static bool opt_rem_fin = false;
+static bool opt_clean_acc = false;
 static spot::acc_cond::mark_t opt_mask_acc = 0U;
 static std::vector<bool> opt_keep_states = {};
 static unsigned int opt_keep_states_initial = 0;
@@ -251,6 +256,9 @@ parse_opt(int key, char* arg, struct argp_state*)
     case OPT_ARE_ISOMORPHIC:
       opt->are_isomorphic = read_automaton(arg, opt->dict);
       break;
+    case OPT_CLEAN_ACC:
+      opt_clean_acc = true;
+      break;
     case OPT_EDGES:
       opt_edges = parse_range(arg, 0, std::numeric_limits<int>::max());
       break;
@@ -421,6 +429,8 @@ namespace
       if (opt_dnf_acc)
 	aut->set_acceptance(aut->acc().num_sets(),
 			    aut->get_acceptance().to_dnf());
+      if (opt_clean_acc && !opt_rem_fin)
+	cleanup_acceptance(aut);
       if (opt_rem_fin)
 	aut = remove_fin(aut);
 

src/tgba/acc.hh

@@ -585,7 +585,7 @@ namespace spot
       uses_fin_acceptance_ = check_fin_acceptance();
     }
 
-    acc_code get_acceptance() const
+    const acc_code& get_acceptance() const
     {
       return code_;
     }

src/tgba/tgba.hh

@@ -639,7 +639,7 @@ namespace spot
     acc_cond acc_;
 
   public:
-    acc_cond::acc_code get_acceptance() const
+    const acc_cond::acc_code& get_acceptance() const
     {
       return acc_.get_acceptance();
     }

src/tgbaalgos/Makefile.am

@@ -31,6 +31,7 @@ tgbaalgos_HEADERS = \
   are_isomorphic.hh \
   bfssteps.hh \
   canonicalize.hh \
+  cleanacc.hh \
   complete.hh \
   compsusp.hh \
   cycles.hh \
@@ -84,6 +85,7 @@ libtgbaalgos_la_SOURCES = \
   are_isomorphic.cc \
   bfssteps.cc \
   canonicalize.cc \
+  cleanacc.cc \
   complete.cc \
   compsusp.cc \
   cycles.cc \

src/tgbaalgos/cleanacc.cc

@@ -0,0 +1,135 @@
+// -*- coding: utf-8 -*-
+// Copyright (C) 2015 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/>.
+
+#include "tgbaalgos/cleanacc.hh"
+
+namespace spot
+{
+  namespace
+  {
+    acc_cond::acc_code strip(const acc_cond& acc,
+			     const acc_cond::acc_word* pos,
+			     acc_cond::mark_t useless)
+    {
+      auto start = pos - pos->size;
+      switch (pos->op)
+	{
+	case acc_cond::acc_op::And:
+	  {
+	    --pos;
+	    acc_cond::acc_code res;
+	    do
+	      {
+		auto tmp = strip(acc, pos, useless);
+		tmp.append_and(std::move(res));
+		std::swap(tmp, res);
+		pos -= pos->size + 1;
+	      }
+	    while (pos > start);
+	    return res;
+	  }
+	case acc_cond::acc_op::Or:
+	  {
+	    --pos;
+	    acc_cond::acc_code res = acc.fin(0); // f
+	    do
+	      {
+		auto tmp = strip(acc, pos, useless);
+		tmp.append_or(std::move(res));
+		std::swap(tmp, res);
+		pos -= pos->size + 1;
+	      }
+	    while (pos > start);
+	    return res;
+	  }
+	case acc_cond::acc_op::Fin:
+	  if (pos[-1].mark & useless)
+	    return acc.inf(0U);	// t
+	  return acc.fin(acc.strip(pos[-1].mark, useless));
+	case acc_cond::acc_op::Inf:
+	  if (pos[-1].mark & useless)
+	    return acc.fin(0U);	// f
+	  return acc.inf(acc.strip(pos[-1].mark, useless));
+	case acc_cond::acc_op::FinNeg:
+	case acc_cond::acc_op::InfNeg:
+	  SPOT_UNREACHABLE();
+	  return acc_cond::acc_code{};
+	}
+      SPOT_UNREACHABLE();
+      return acc_cond::acc_code{};
+    }
+  }
+
+  void cleanup_acceptance(tgba_digraph_ptr& aut)
+  {
+    auto& acc = aut->acc();
+    if (acc.num_sets() == 0)
+      return;
+
+    auto& c = aut->get_acceptance();
+    acc_cond::mark_t used_in_cond = 0U;
+    if (!c.is_true())
+      {
+	auto pos = &c.back();
+	auto end = &c.front();
+	while (pos > end)
+	  {
+	    switch (pos->op)
+	      {
+	      case acc_cond::acc_op::And:
+	      case acc_cond::acc_op::Or:
+		--pos;
+		break;
+	      case acc_cond::acc_op::Fin:
+	      case acc_cond::acc_op::Inf:
+	      case acc_cond::acc_op::FinNeg:
+	      case acc_cond::acc_op::InfNeg:
+		used_in_cond |= pos[-1].mark;
+		pos -= 2;
+		break;
+	      }
+	  }
+      }
+
+    acc_cond::mark_t used_in_aut = 0U;
+    for (auto& t: aut->transitions())
+      used_in_aut |= t.acc;
+
+    auto useful = used_in_aut & used_in_cond;
+
+    auto useless = acc.comp(useful);
+
+    if (!useless)
+      return;
+
+    // Remove useless marks from the automaton
+    for (auto& t: aut->transitions())
+      t.acc = acc.strip(t.acc, useless);
+
+    // Remove useless marks from the acceptance condition
+    acc_cond::acc_code newc;
+    if (c.is_true() || c.is_false())
+      newc = c;
+    else
+      newc = strip(acc, &c.back(), useless);
+
+    aut->set_acceptance(useful.count(), newc);
+  }
+
+}

src/tgbaalgos/cleanacc.hh

@@ -0,0 +1,32 @@
+// -*- coding: utf-8 -*-
+// Copyright (C) 2015 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/>.
+
+#ifndef SPOT_TGBAALGOS_CLEANACC_HH
+# define SPOT_TGBAALGOS_CLEANACC_HH
+
+#include "tgba/tgbagraph.hh"
+
+namespace spot
+{
+  /// \brief Remove useless acceptance sets
+  SPOT_API void
+  cleanup_acceptance(tgba_digraph_ptr& aut);
+}
+
+#endif // SPOT_TGBAALGOS_CLEANACC_HH

src/tgbatest/hoaparse.test

@@ -1394,48 +1394,48 @@ State: 0
 EOF
 
 
-# FIXME: Test removal of useless acceptance sets
-#
-# # The mapping of acceptance sets for the second automaton is
-# #   input   ->  output
-# #     0     ->    0
-# #     1     ->   removed
-# #     2     ->    1
-# #     3     ->   removed
-# #     4     ->    2
-# #    !2     ->    3
-# expectok input <<EOF
-# HOA: v1
-# name: "TGBA for Fa"
-# States: 2
-# Start: 0
-# AP: 1 "a"
-# acc-name: all
-# Acceptance: 0 t
-# properties: trans-labels explicit-labels state-acc complete deterministic
-# --BODY--
-# State: 0 "F(a)"
-# [0] 1
-# [!0] 0
-# State: 1 "t"
-# [t] 1
-# --END--
-# HOA: v1
-# States: 1
-# Start: 0
-# AP: 3 "a" "b" "c"
-# acc-name: generalized-Buchi 4
-# Acceptance: 4 Inf(0)&Inf(1)&Inf(2)&Inf(3)
-# properties: trans-labels explicit-labels trans-acc complete deterministic
-# --BODY--
-# State: 0
-# [0&1&2] 0 {0 1 2}
-# [!0&1&2] 0 {1 2}
-# [0&!1&2] 0 {0 1}
-# [!0&!1&2] 0 {1}
-# [0&1&!2] 0 {0 2 3}
-# [!0&1&!2] 0 {2 3}
-# [0&!1&!2] 0 {0 3}
-# [!0&!1&!2] 0 {3}
-# --END--
-# EOF
+# Test removal of useless acceptance sets
+
+# The mapping of acceptance sets for the second automaton is
+#   input   ->  output
+#     0     ->    0
+#     1     ->   removed
+#     2     ->    1
+#     3     ->   removed
+#     4     ->    2
+#    !2     ->    3
+expectok input --cleanup-acc <<EOF
+HOA: v1
+name: "TGBA for Fa"
+States: 2
+Start: 0
+AP: 1 "a"
+acc-name: all
+Acceptance: 0 t
+properties: trans-labels explicit-labels state-acc complete deterministic
+--BODY--
+State: 0 "F(a)"
+[0] 1
+[!0] 0
+State: 1 "t"
+[t] 1
+--END--
+HOA: v1
+States: 1
+Start: 0
+AP: 3 "a" "b" "c"
+acc-name: generalized-Buchi 4
+Acceptance: 4 Inf(0)&Inf(1)&Inf(2)&Inf(3)
+properties: trans-labels explicit-labels trans-acc complete deterministic
+--BODY--
+State: 0
+[0&1&2] 0 {0 1 2}
+[!0&1&2] 0 {1 2}
+[0&!1&2] 0 {0 1}
+[!0&!1&2] 0 {1}
+[0&1&!2] 0 {0 2 3}
+[!0&1&!2] 0 {2 3}
+[0&!1&!2] 0 {0 3}
+[!0&!1&!2] 0 {3}
+--END--
+EOF