streett_to_generalized_buchi() now works on Streett-like

* NEWS: Mention the modification.
* spot/twaalgos/remfin.cc: Adapt to avoid infinite recursion.
* spot/twaalgos/totgba.cc: Work on Streett-like.
* tests/Makefile.am, tests/python/streett_totgba.py: Tests the
  modification.
* tests/core/remfin.test: Fix one test case that is now handled by
  the modification.

NEWS

@@ -111,6 +111,9 @@ New in spot 2.3.4.dev (not yet released)
     some simplifications on an acceptance condition, and might lead
     to the removal of some acceptance sets.
 
+  - The function spot::streett_to_generalized_buchi() is now able to
+    work on automatons with Streett-like acceptance.
+
   Python:
 
   - The 'spot.gen' package exports the functions from libspotgen.

spot/twaalgos/remfin.cc

@@ -444,7 +444,9 @@ namespace spot
 
     twa_graph_ptr street_strategy(const const_twa_graph_ptr& aut)
     {
-      return streett_to_generalized_buchi_maybe(aut);
+      return (aut->get_acceptance().used_inf_fin_sets().first)
+             ? streett_to_generalized_buchi_maybe(aut)
+             : nullptr;
     }
 
     twa_graph_ptr rabin_strategy(const const_twa_graph_ptr& aut)

spot/twaalgos/totgba.cc

@@ -116,17 +116,35 @@ namespace spot
     // do not do anything.
     if (in->acc().is_generalized_buchi())
       return std::const_pointer_cast<twa_graph>(in);
-    int p = in->acc().is_streett();
+
-    if (p <= 0)
+    std::vector<acc_cond::rs_pair> pairs;
+    bool res = in->acc().is_streett_like(pairs);
+    if (!res)
       throw std::runtime_error("streett_to_generalized_buchi() should only be"
-                               " called on automata with Streett acceptance");
+                               " called on automata with Streett-like"
+                               " acceptance");
 
     // In Streett acceptance, inf sets are odd, while fin sets are
     // even.
     acc_cond::mark_t inf;
     acc_cond::mark_t fin;
     std::tie(inf, fin) = in->get_acceptance().used_inf_fin_sets();
-    assert((inf >> 1U) == fin);
+    unsigned p = inf.count();
+
+    if (!p)
+      return remove_fin(in);
+
+    unsigned numsets = in->acc().num_sets();
+    std::vector<acc_cond::mark_t> fin_to_infpairs(numsets, 0U);
+    std::vector<acc_cond::mark_t> inf_to_finpairs(numsets, 0U);
+    for (auto pair: pairs)
+      {
+        for (unsigned mark: pair.fin.sets())
+          fin_to_infpairs[mark] |= pair.inf;
+
+        for (unsigned mark: pair.inf.sets())
+          inf_to_finpairs[mark] |= pair.fin;
+      }
 
     scc_info si(in);
 
@@ -139,8 +157,16 @@ namespace spot
         auto acc = si.acc_sets_of(s); // {0,1,2,3,4,6,7,9}
         auto acc_fin = acc & fin;     // {0,  2,  4,6}
         auto acc_inf = acc & inf;     // {  1,  3,    7,9}
-        auto fin_wo_inf = acc_fin - (acc_inf >> 1U); // {4}
+        acc_cond::mark_t fin_wo_inf = 0U;
-        auto inf_wo_fin = acc_inf - (acc_fin << 1U); // {9}
+        for (unsigned mark: acc_fin.sets())
+          if (!fin_to_infpairs[mark] || (fin_to_infpairs[mark] - acc_inf))
+            fin_wo_inf |= {mark};
+
+        acc_cond::mark_t inf_wo_fin = 0U;
+        for (unsigned mark: acc_inf.sets())
+          if (!inf_to_finpairs[mark] || (inf_to_finpairs[mark] - acc_fin))
+            inf_wo_fin |= {mark};
+
         sccfi.emplace_back(fin_wo_inf, inf_wo_fin, acc_fin == 0U);
       }
 
@@ -199,12 +225,14 @@ namespace spot
                   continue;
                 // For any Fin set we see, we want to see the
                 // corresponding Inf set.
-                pend |= (t.acc & fin) << 1U;
+                for (unsigned mark: (t.acc & fin).sets())
+                  pend |= fin_to_infpairs[mark];
+
                 pend -= t.acc & inf;
                 // Label this transition with all non-pending
                 // inf sets.  The strip will shift everything
                 // to the correct numbers in the targets.
-                acc = (inf - pend).strip(fin) & outall;
+                acc = (inf - pend).strip(fin - inf) & outall;
                 // Adjust the pending sets to what will be necessary
                 // required on the destination state.
                 if (sbacc)
@@ -212,7 +240,9 @@ namespace spot
                     auto a = in->state_acc_sets(t.dst);
                     if (a & scc_fin_wo_inf)
                       continue;
-                    pend |= (a & fin) << 1U;
+                    for (unsigned m: (a & fin).sets())
+                      pend |= fin_to_infpairs[m];
+
                     pend -= a & inf;
                   }
                 pend |= scc_inf_wo_fin;
@@ -244,16 +274,18 @@ namespace spot
             // this has to occur at least once per cycle.
             if (pend == orig_copy && (t.src >= t.dst) && maybe_acc && !no_fin)
               {
-                acc_cond::mark_t pend = 0U;
+                acc_cond::mark_t stpend = 0U;
                 if (sbacc)
                   {
                     auto a = in->state_acc_sets(t.dst);
                     if (a & scc_fin_wo_inf)
                       continue;
-                    pend = (a & fin) << 1U;
+                    for (unsigned m: (a & fin).sets())
-                    pend -= a & inf;
+                      stpend |= fin_to_infpairs[m];
+
+                    stpend -= a & inf;
                   }
-                st2gba_state d(t.dst, pend | scc_inf_wo_fin);
+                st2gba_state d(t.dst, stpend | scc_inf_wo_fin);
                 // Have we already seen this destination?
                 unsigned dest;
                 auto dres = bs2num.emplace(d, 0);
@@ -287,7 +319,7 @@ namespace spot
   twa_graph_ptr
   streett_to_generalized_buchi_maybe(const const_twa_graph_ptr& in)
   {
-    static int min = [&]() {
+    static unsigned min = [&]() {
       const char* c = getenv("SPOT_STREETT_CONV_MIN");
       if (!c)
         return 3;
@@ -297,12 +329,16 @@ namespace spot
         throw std::runtime_error("unexpected value for SPOT_STREETT_CONV_MIN");
       return val;
     }();
-    if (min == 0 || min > in->acc().is_streett())
+
+    std::vector<acc_cond::rs_pair> pairs;
+    in->acc().is_streett_like(pairs);
+    if (min == 0 || min > pairs.size())
       return nullptr;
     else
       return streett_to_generalized_buchi(in);
   }
 
+
   /// \brief Take an automaton with any acceptance condition and return
   /// an equivalent Generalized Büchi automaton.
   twa_graph_ptr

tests/Makefile.am

@@ -365,6 +365,7 @@ TESTS_python = \
   python/setacc.py \
   python/setxor.py \
   python/simstate.py \
+  python/streett_totgba.py \
   python/rs_like.py \
   python/sum.py \
   python/trival.py \

tests/core/remfin.test

@@ -579,7 +579,7 @@ Start: 0
 AP: 2 "a" "b"
 acc-name: generalized-Buchi 12
 Acceptance: 12 $acctwelve
-properties: trans-labels explicit-labels trans-acc complete
+properties: trans-labels explicit-labels state-acc complete
 --BODY--
 State: 0
 [!0] 0
@@ -594,8 +594,8 @@ State: 1
 [1] 4
 State: 2
 [t] 2
-[1] 4
 [!1] 5
+[1] 4
 State: 3
 [t] 3
 [1] 4
@@ -607,8 +607,8 @@ State: 4
 [!1] 9
 State: 5
 [t] 5
-[1] 7
 [1] 10
+[1] 7
 [1] 11
 State: 6
 [t] 6
@@ -617,8 +617,8 @@ State: 6
 [1] 13
 State: 7
 [t] 7
-[!1] 9
 [1] 11
+[!1] 9
 State: 8
 [t] 8
 [!1] 9
@@ -630,12 +630,12 @@ State: 9
 [1] 16
 State: 10
 [t] 10
-[1] 11
 [!1] 17
+[1] 11
 State: 11
 [t] 11
-[!1] 14
 [!1] 18
+[!1] 14
 [!1] 19
 State: 12
 [t] 12
@@ -648,8 +648,8 @@ State: 13
 [!1] 22
 State: 14
 [t] 14
-[1] 16
 [!1] 19
+[1] 16
 State: 15
 [t] 15
 [1] 16
@@ -660,40 +660,40 @@ State: 16
 [!1] 24
 [!1] 25
 State: 17
-[!1] 17
 [1] 26
+[!1] 17
 [1] 27
 State: 18
+[1] 27
 [!1] 18
 [!1] 19
-[1] 27
 State: 19
-[!1] 19
 [1] 28
+[!1] 19
 [1] 29
 State: 20
-[!1] 20
 [1] 30
 [1] 31
+[!1] 20
 State: 21
+[1] 31
 [!1] 21
 [!1] 22
-[1] 31
 State: 22
-[!1] 22
 [1] 32
 [1] 33
+[!1] 22
 State: 23
+[1] 29
 [!1] 23
 [!1] 25
-[1] 29
 State: 24
+[1] 33
 [!1] 24
 [!1] 25
-[1] 33
 State: 25
-[!1] 25 {0 1 2 3 4 6 7 8 9 10}
 [1] 34
+[!1] 25
 State: 26
 [t] 26
 [1] 27
@@ -718,14 +718,14 @@ State: 32
 State: 33
 [t] 33
 [!1] 36
-State: 34
+State: 34 {0 1 2 3 4 5 6 7 8 9 10 11}
-[t] 34 {0 1 2 3 4 5 6 7 8 9 10 11}
+[t] 34
 State: 35
 [1] 34
-[!1] 35 {0 1 2 3 4 6 7 8 9 10 11}
+[!1] 35
 State: 36
 [1] 34
-[!1] 36 {0 1 2 3 4 5 6 7 8 9 10}
+[!1] 36
 --END--
 HOA: v1
 States: 2

tests/python/streett_totgba.py

@@ -0,0 +1,84 @@
+#!/usr/bin/python3
+# -*- mode: python; coding: utf-8 -*-
+# Copyright (C) 2017 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/>.
+
+import spot
+import os
+import shutil
+import sys
+
+def parse_multiple_auts(hoa):
+  l = hoa.split('--END--')
+  a = []
+  cpt = 0
+  for x in l:
+    if x.isspace() or x == '':
+      continue
+    x = x + "--END--"
+    a.append(spot.automaton(x))
+
+  return a
+
+def ensure_deterministic(a):
+  if a.is_existential() and spot.is_deterministic(a):
+    return a
+
+  return a.postprocess('Generic', 'deterministic', 'Low')
+
+def equivalent(a1, a2):
+  na1 = spot.dualize(ensure_deterministic(a1))
+  na2 = spot.dualize(ensure_deterministic(a2))
+  return (not a1.intersects(na2)) and (not a2.intersects(na1))
+
+def tgba(a):
+  if not a.is_existential():
+    a = spot.remove_alternation(a)
+  a = spot.to_generalized_buchi(a)
+  return a
+
+def test_aut(aut):
+  stgba = tgba(aut)
+  assert equivalent(stgba, aut)
+  os.environ["SPOT_STREETT_CONV_MIN"] = '1'
+  sftgba = tgba(aut)
+  del os.environ["SPOT_STREETT_CONV_MIN"]
+  assert equivalent(stgba, sftgba)
+
+  slike = spot.simplify_acceptance(aut)
+
+  sltgba = tgba(slike)
+  os.environ["SPOT_STREETT_CONV_MIN"] = "1"
+  slftgba = tgba(slike)
+  del os.environ["SPOT_STREETT_CONV_MIN"]
+  assert equivalent(sltgba, slftgba)
+
+# Those automatons are generated with ltl2dstar, which is NOT part of spot,
+# using the following command:
+# genltl --eh-patterns --dac-patterns --hkrss-patterns --sb-patterns |\
+# ltldo "ltl2dstar --automata=streett --output-format=hoa\
+#       --ltl2nba=spin:ltl2tgba@-s %L ->%O" -F- --name=%f -H"
+
+if shutil.which('ltl2dstar') is None:
+  sys.exit(77)
+for a in spot.automata('genltl --eh-patterns --dac-patterns --hkrss-patterns\
+                        --sb-patterns |\
+                        ltldo "ltl2dstar --automata=streett --output-format=hoa\
+                        --ltl2nba=spin:ltl2tgba@-s %L ->%O"\
+                        -T5 -F- --name=%f -H|'):
+  test_aut(a)