acc: refactor strip() routines

* src/tgba/acc.cc, src/tgba/acc.hh: Move the strip() routine from
acc_cond into acc_cond::mark_t, and the strip() routine from
cleanacc.cc into acc_cond::acc_code.  Introduce helper functions
to create inf()/fin()/t()/f() at the acc_code level.
* src/tgbaalgos/cleanacc.cc: Simplify, using the strip() function
from acc_code.
* src/tgbaalgos/mask.cc (mask_acc_sets): Use the strip() function
from acc_code so that it work on non-Buchi acceptance.
* src/tgbatest/maskacc.test: Add a test for the latter change.
* src/tgbaalgos/sccfilter.cc, src/tgbatest/acc.cc: Adjust the
use mark_t::strip().

src/tgba/acc.cc

@@ -414,18 +414,12 @@ namespace spot
     acc_cond::acc_code complement_rec(const acc_cond::acc_word* pos)
     {
       auto start = pos - pos->size;
-
-      acc_cond::acc_code res;
-      res.resize(2);
-      res[0].mark = 0U;
-      res[1].size = 1;
-
       switch (pos->op)
 	{
 	case acc_cond::acc_op::And:
 	  {
 	    --pos;
-	    res[1].op = acc_cond::acc_op::Fin; // f
+	    auto res = acc_cond::acc_code::f();
 	    do
 	      {
 		auto tmp = complement_rec(pos);
@@ -439,7 +433,7 @@ namespace spot
 	case acc_cond::acc_op::Or:
 	  {
 	    --pos;
-	    res[1].op = acc_cond::acc_op::Inf; // t
+	    auto res = acc_cond::acc_code::t();
 	    do
 	      {
 		auto tmp = complement_rec(pos);
@@ -451,24 +445,16 @@ namespace spot
 	    return res;
 	  }
 	case acc_cond::acc_op::Fin:
-	  res[0].mark = pos[-1].mark;
+	  return acc_cond::acc_code::inf(pos[-1].mark);
-	  res[1].op = acc_cond::acc_op::Inf;
-	  return res;
 	case acc_cond::acc_op::Inf:
-	  res[0].mark = pos[-1].mark;
+	  return acc_cond::acc_code::fin(pos[-1].mark);
-	  res[1].op = acc_cond::acc_op::Fin;
-	  return res;
 	case acc_cond::acc_op::FinNeg:
-	  res[0].mark = pos[-1].mark;
+	  return acc_cond::acc_code::inf_neg(pos[-1].mark);
-	  res[1].op = acc_cond::acc_op::InfNeg;
-	  return res;
 	case acc_cond::acc_op::InfNeg:
-	  res[0].mark = pos[-1].mark;
+	  return acc_cond::acc_code::fin_neg(pos[-1].mark);
-	  res[1].op = acc_cond::acc_op::FinNeg;
-	  return res;
 	}
       SPOT_UNREACHABLE();
-      return acc_cond::acc_code{};
+      return {};
     }
 
   }
@@ -476,18 +462,101 @@ namespace spot
 
   acc_cond::acc_code acc_cond::acc_code::complement() const
   {
-    if (empty())
+    if (is_true())
-      {
+      return acc_cond::acc_code::f();
-	acc_cond::acc_code res;
-	res.resize(2);
-	res[0].mark = 0U;
-	res[1].op = acc_cond::acc_op::Fin;
-	res[1].size = 1;
-	return res;
-      }
     return complement_rec(&back());
   }
 
+  namespace
+  {
+    static acc_cond::acc_code
+    strip_rec(const acc_cond::acc_word* pos, acc_cond::mark_t rem, bool missing)
+    {
+      auto start = pos - pos->size;
+      switch (pos->op)
+	{
+	case acc_cond::acc_op::And:
+	  {
+	    --pos;
+	    auto res = acc_cond::acc_code::t();
+	    do
+	      {
+		auto tmp = strip_rec(pos, rem, missing);
+		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;
+	    auto res = acc_cond::acc_code::f();
+	    do
+	      {
+		auto tmp = strip_rec(pos, rem, missing);
+		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 (missing && (pos[-1].mark & rem))
+	    return acc_cond::acc_code::t();
+	  return acc_cond::acc_code::fin(pos[-1].mark.strip(rem));
+	case acc_cond::acc_op::Inf:
+	  if (missing && (pos[-1].mark & rem))
+	    return acc_cond::acc_code::f();
+	  return acc_cond::acc_code::inf(pos[-1].mark.strip(rem));
+	case acc_cond::acc_op::FinNeg:
+	case acc_cond::acc_op::InfNeg:
+	  SPOT_UNREACHABLE();
+	  return {};
+	}
+      SPOT_UNREACHABLE();
+      return {};
+    }
+  }
+
+  acc_cond::acc_code
+  acc_cond::acc_code::strip(acc_cond::mark_t rem, bool missing) const
+  {
+    if (is_true() || is_false())
+      return *this;
+    return strip_rec(&back(), rem, missing);
+  }
+
+  acc_cond::mark_t
+  acc_cond::acc_code::used_sets() const
+  {
+    if (is_true() || is_false())
+      return 0U;
+    acc_cond::mark_t used_in_cond = 0U;
+    auto pos = &back();
+    auto end = &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;
+	  }
+      }
+    return used_in_cond;
+  }
+
   std::ostream& operator<<(std::ostream& os,
 			   const spot::acc_cond::acc_code& code)
   {

src/tgba/acc.hh

@@ -145,6 +145,29 @@ namespace spot
 	return id ^ r.id;
       }
 
+      mark_t strip(mark_t y) const
+      {
+	// strip every bit of id that is marked in y
+	//       100101110100.strip(
+	//       001011001000)
+	//   ==  10 1  11 100
+	//   ==      10111100
+
+	auto xv = id;		// 100101110100
+	auto yv = y.id;		// 001011001000
+
+	while (yv && xv)
+	  {
+	    // Mask for everything after the last 1 in y
+	    auto rm = (~yv) & (yv - 1);	// 000000000111
+	    // Mask for everything before the last 1 in y
+	    auto lm = ~(yv ^ (yv - 1));	// 111111110000
+	    xv = ((xv & lm) >> 1) | (xv & rm);
+	    yv = (yv & lm) >> 1;
+	  }
+	return xv;
+      }
+
       // Number of bits sets.
       unsigned count() const
       {
@@ -321,6 +344,61 @@ namespace spot
 	  && (*this)[s - 1].op == acc_op::Fin && (*this)[s - 2].mark == 0U;
       }
 
+      static acc_code f()
+      {
+	acc_code res;
+	res.resize(2);
+	res[0].mark = 0U;
+	res[1].op = acc_op::Fin;
+	res[1].size = 1;
+	return res;
+      }
+
+      static acc_code t()
+      {
+	return {};
+      }
+
+      static acc_code fin(mark_t m)
+      {
+	acc_code res;
+	res.resize(2);
+	res[0].mark = m;
+	res[1].op = acc_op::Fin;
+	res[1].size = 1;
+	return res;
+      }
+
+      static acc_code fin_neg(mark_t m)
+      {
+	acc_code res;
+	res.resize(2);
+	res[0].mark = m;
+	res[1].op = acc_op::FinNeg;
+	res[1].size = 1;
+	return res;
+      }
+
+      static acc_code inf(mark_t m)
+      {
+	acc_code res;
+	res.resize(2);
+	res[0].mark = m;
+	res[1].op = acc_op::Inf;
+	res[1].size = 1;
+	return res;
+      }
+
+      static acc_code inf_neg(mark_t m)
+      {
+	acc_code res;
+	res.resize(2);
+	res[0].mark = m;
+	res[1].op = acc_op::InfNeg;
+	res[1].size = 1;
+	return res;
+      }
+
       void append_and(acc_code&& r)
       {
 	if (is_true() || r.is_false())
@@ -562,6 +640,24 @@ namespace spot
 
       acc_code complement() const;
 
+      // Remove all the acceptance sets in rem.
+      //
+      // If MISSING is set, the acceptance sets are assumed to be
+      // missing from the automaton, and the acceptance is updated to
+      // reflect this.  For instance (Inf(1)&Inf(2))|Fin(3) will
+      // become Fin(3) if we remove 2 because it is missing from this
+      // automaton, because there is no way to fulfill Inf(1)&Inf(2)
+      // in this case.  So essentially MISSING causes Inf(rem) to
+      // become f, and Fin(rem) to become t.
+      //
+      // If MISSING is unset, Inf(rem) become t while Fin(rem) become
+      // f.  Removing 2 from (Inf(1)&Inf(2))|Fin(3) would then give
+      // Inf(1)|Fin(3).
+      acc_code strip(acc_cond::mark_t rem, bool missing) const;
+
+      // Return the set of sets appearing in the condition.
+      acc_cond::mark_t used_sets() const;
+
       SPOT_API
       friend std::ostream& operator<<(std::ostream& os, const acc_code& code);
     };
@@ -609,26 +705,25 @@ namespace spot
 	(s == 2 && code_[1].op == acc_op::Inf && code_[0].mark == all_sets());
     }
 
+    bool is_buchi() const
+    {
+      unsigned s = code_.size();
+      return num_ == 1 &&
+	s == 2 && code_[1].op == acc_op::Inf && code_[0].mark == all_sets();
+    }
+
+    bool is_true() const
+    {
+      return code_.is_true();
+    }
+
   protected:
     bool check_fin_acceptance() const;
 
-    acc_code primitive(mark_t mark, acc_op op) const
-    {
-      acc_word w1;
-      w1.mark = mark;
-      acc_word w2;
-      w2.op = op;
-      w2.size = 1;
-      acc_code c;
-      c.push_back(w1);
-      c.push_back(w2);
-      return c;
-    }
-
   public:
     acc_code inf(mark_t mark) const
     {
-      return primitive(mark, acc_op::Inf);
+      return acc_code::inf(mark);
     }
 
     acc_code inf(std::initializer_list<unsigned> vals) const
@@ -638,7 +733,7 @@ namespace spot
 
     acc_code inf_neg(mark_t mark) const
     {
-      return primitive(mark, acc_op::InfNeg);
+      return acc_code::inf_neg(mark);
     }
 
     acc_code inf_neg(std::initializer_list<unsigned> vals) const
@@ -648,7 +743,7 @@ namespace spot
 
     acc_code fin(mark_t mark) const
     {
-      return primitive(mark, acc_op::Fin);
+      return acc_code::fin(mark);
     }
 
     acc_code fin(std::initializer_list<unsigned> vals) const
@@ -658,7 +753,7 @@ namespace spot
 
     acc_code fin_neg(mark_t mark) const
     {
-      return primitive(mark, acc_op::FinNeg);
+      return acc_code::fin_neg(mark);
     }
 
     acc_code fin_neg(std::initializer_list<unsigned> vals) const
@@ -795,30 +890,6 @@ namespace spot
       return u;
     }
 
-    mark_t strip(mark_t x, mark_t y) const
-    {
-      // strip every bit of x that is marked in y
-      // strip(100101110100,
-      //       001011001000)
-      //   ==  10 1  11 100
-      //   ==      10111100
-
-      auto xv = x.id;		// 100101110100
-      auto yv = y.id;		// 001011001000
-
-      while (yv && xv)
-	{
-	  // Mask for everything after the last 1 in y
-	  auto rm = (~yv) & (yv - 1);	// 000000000111
-	  // Mask for everything before the last 1 in y
-	  auto lm = ~(yv ^ (yv - 1));	// 111111110000
-	  xv = ((xv & lm) >> 1) | (xv & rm);
-	  yv = (yv & lm) >> 1;
-	}
-
-      return xv;
-    }
-
   protected:
     mark_t::value_t mark_(unsigned u) const
     {

src/tgbaalgos/cleanacc.cc

@@ -21,61 +21,6 @@
 
 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();
@@ -83,29 +28,7 @@ namespace spot
       return;
 
     auto& c = aut->get_acceptance();
-    acc_cond::mark_t used_in_cond = 0U;
+    acc_cond::mark_t used_in_cond = c.used_sets();
-    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())
@@ -120,16 +43,10 @@ namespace spot
 
     // Remove useless marks from the automaton
     for (auto& t: aut->transitions())
-      t.acc = acc.strip(t.acc, useless);
+      t.acc = t.acc.strip(useless);
 
     // Remove useless marks from the acceptance condition
-    acc_cond::acc_code newc;
+    aut->set_acceptance(useful.count(), c.strip(useless, true));
-    if (c.is_true() || c.is_false())
-      newc = c;
-    else
-      newc = strip(acc, &c.back(), useless);
-
-    aut->set_acceptance(useful.count(), newc);
   }
 
 }

src/tgbaalgos/mask.cc

@@ -24,14 +24,14 @@ namespace spot
   tgba_digraph_ptr mask_acc_sets(const const_tgba_digraph_ptr& in,
 				 acc_cond::mark_t to_remove)
   {
-    auto& inacc = in->acc();
     auto res = make_tgba_digraph(in->get_dict());
     res->copy_ap_of(in);
     res->prop_copy(in, { true, false, true, true });
-    unsigned na = inacc.num_sets();
+    unsigned na = in->acc().num_sets();
     unsigned tr = to_remove.count();
     assert(tr <= na);
-    res->set_generalized_buchi(na - tr);
+    res->set_acceptance(na - tr,
+			in->get_acceptance().strip(to_remove, false));
     transform_accessible(in, res, [&](unsigned,
                                       bdd& cond,
                                       acc_cond::mark_t& acc,
@@ -40,7 +40,7 @@ namespace spot
                            if (acc & to_remove)
                              cond = bddfalse;
                            else
-                             acc = inacc.strip(acc, to_remove);
+                             acc = acc.strip(to_remove);
                          });
     return res;
   }

src/tgbaalgos/sccfilter.cc

@@ -1,6 +1,6 @@
 // -*- coding: utf-8 -*-
-// Copyright (C) 2009, 2010, 2011, 2012, 2013, 2014 Laboratoire de
+// Copyright (C) 2009, 2010, 2011, 2012, 2013, 2014, 2015 Laboratoire
-// Recherche et Développement de l'Epita (LRDE).
+// de Recherche et Développement de l'Epita (LRDE).
 //
 // This file is part of Spot, a model checking library.
 //
@@ -240,7 +240,7 @@ namespace spot
 	    if (!this->si->is_accepting_scc(u))
 	      acc = 0U;
 	    else
-	      acc = this->si->get_aut()->acc().strip(acc, strip_[u]);
+	      acc = acc.strip(strip_[u]);
 	  }
 	return filtered_trans{keep, cond, acc};
       }

src/tgbatest/acc.cc

@@ -103,7 +103,7 @@ int main()
   for (auto& v: s)
     {
       check(ac, v);
-      check(ac, ac.strip(v, u));
+      check(ac, v.strip(u));
     }
 
 

src/tgbatest/maskacc.test

@@ -111,6 +111,51 @@ diff output expect3
 run 0 ../../bin/autfilt --mask-acc=0 --mask-acc=1 input1 -H >output
 diff output expect3
 
+cat >input4 <<EOF
+HOA: v1
+States: 4
+Start: 0
+AP: 2 "a" "b"
+acc-name: generalized-Buchi 2
+Acceptance: 3 Inf(1)|Fin(0)
+properties: trans-labels explicit-labels trans-acc
+--BODY--
+State: 0
+[0] 1 {0}
+[1] 2 {1}
+State: 1
+[0] 2
+[0] 3 {1}
+State: 2
+[1] 1
+[1] 3 {0}
+State: 3
+[0] 3 {0 1}
+--END--
+EOF
+
+cat >expect4 <<EOF
+HOA: v1
+States: 4
+Start: 0
+AP: 2 "a" "b"
+Acceptance: 2 Inf(0)
+properties: trans-labels explicit-labels trans-acc
+--BODY--
+State: 0
+[1] 1 {0}
+State: 1
+[1] 2
+State: 2
+[0] 1
+[0] 3 {0}
+State: 3
+--END--
+EOF
+
+run 0 ../../bin/autfilt --mask-acc=0 input4 -H >output
+diff output expect4
+
 # Errors
 run 2 ../../bin/autfilt --mask-acc=a3 input1
 run 2 ../../bin/autfilt --mask-acc=3-2 input1