bin: --dot=s display SCCs

* src/tgbaalgos/dotty.cc: Add option 's' to display SCCs.
* src/bin/dstar2tgba.cc, src/bin/common_aoutput.cc: Document it.
* src/tgbatest/neverclaimread.test: Test it.

src/bin/common_aoutput.cc

@@ -51,7 +51,8 @@ static const argp_option options[] =
     { "dot", OPT_DOT, "c|h|n|N|t|v", OPTION_ARG_OPTIONAL,
       "GraphViz's format (default).  Add letters to chose (c) circular nodes, "
       "(h) horizontal layout, (v) vertical layout, (n) with name, "
-      "(N) without name, (t) always transition-based acceptance.", 0 },
+      "(N) without name, (s) with SCCs, "
+      "(t) always transition-based acceptance.", 0 },
     { "hoaf", 'H', "s|t|m|l", OPTION_ARG_OPTIONAL,
       "Output the automaton in HOA format.  Add letters to select "
       "(s) state-based acceptance, (t) transition-based acceptance, "

src/bin/dstar2tgba.cc

 // -*- coding: utf-8 -*-
-// Copyright (C) 2013, 2014 Laboratoire de Recherche et Développement
-// de l'Epita (LRDE).
+// Copyright (C) 2013, 2014, 2015 Laboratoire de Recherche et
+// Développement de l'Epita (LRDE).
 //
 // This file is part of Spot, a model checking library.
 //
@@ -73,7 +73,8 @@ static const argp_option options[] =
     { "dot", OPT_DOT, "c|h|n|N|t|v", OPTION_ARG_OPTIONAL,
       "GraphViz's format (default).  Add letters to chose (c) circular nodes, "
       "(h) horizontal layout, (v) vertical layout, (n) with name, "
-      "(N) without name, (t) always transition-based acceptance.", 0 },
+      "(N) without name, (s) with SCCs, "
+      "(t) always transition-based acceptance.", 0 },
     { "hoaf", 'H', "s|t|m|l", OPTION_ARG_OPTIONAL,
       "Output the automaton in HOA format.  Add letters to select "
       "(s) state-based acceptance, (t) transition-based acceptance, "

src/tgbaalgos/dotty.cc

 // -*- coding: utf-8 -*-
-// Copyright (C) 2011, 2012, 2014 Laboratoire de Recherche et
+// Copyright (C) 2011, 2012, 2014, 2015 Laboratoire de Recherche et
 // Developpement de l'Epita (LRDE).
 // Copyright (C) 2003, 2004  Laboratoire d'Informatique de Paris 6 (LIP6),
 // département Systèmes Répartis Coopératifs (SRC), Université Pierre
@@ -30,6 +30,7 @@
 #include "misc/escape.hh"
 #include "tgba/tgbagraph.hh"
 #include "tgba/formula2bdd.hh"
+#include "tgbaalgos/sccinfo.hh"
 
 namespace spot
 {
@@ -43,6 +44,7 @@ namespace spot
       bool opt_name_ = true;
       bool opt_circles_ = false;
       bool mark_states_ = false;
+      bool opt_scc_ = false;
       const_tgba_digraph_ptr aut_;
 
     public:
@@ -65,6 +67,9 @@ namespace spot
 	      case 'N':
 		opt_name_ = false;
 	        break;
+	      case 's':
+		opt_scc_ = true;
+		break;
 	      case 'v':
 		opt_horizontal_ = false;
 		break;
@@ -128,11 +133,25 @@ namespace spot
       {
 	aut_ = aut;
 	mark_states_ = !opt_force_acc_trans_ && aut_->has_state_based_acc();
+	auto si =
+	  std::unique_ptr<scc_info>(opt_scc_ ? new scc_info(aut) : nullptr);
 	start();
+	if (si)
+	  {
+	    unsigned sccs = si->scc_count();
+	    for (unsigned i = 0; i < sccs; ++i)
+	      {
+		os_ << "  subgraph cluster_" << i << " {\n";
+		for (auto s: si->states_of(i))
+		  process_state(s);
+		os_ << "  }\n";
+	      }
+	  }
 	unsigned ns = aut_->num_states();
 	for (unsigned n = 0; n < ns; ++n)
 	  {
-	    process_state(n);
+	    if (!si)
+	      process_state(n);
 	    for (auto& t: aut_->out(n))
 	      process_link(t);
 	  }

src/tgbatest/neverclaimread.test

 #!/bin/sh
 # -*- coding: utf-8 -*-
-# Copyright (C) 2010, 2011, 2012, 2013, 2014 Laboratoire de Recherche
-# et Développement de l'Epita (LRDE).
+# Copyright (C) 2010, 2011, 2012, 2013, 2014, 2015 Laboratoire de
+# Recherche et Développement de l'Epita (LRDE).
 #
 # This file is part of Spot, a model checking library.
 #
@@ -322,16 +322,21 @@ accept_all:
   skip
 }
 EOF
-../../bin/autfilt --dot <input >stdout 2>stderr && exit 1
+../../bin/autfilt --dot=sc <input >stdout 2>stderr && exit 1
 cat >expected <<EOF
 digraph G {
   rankdir=LR
+  node [shape="circle"]
   I [label="", style=invis, width=0]
   I -> 0
+  subgraph cluster_0 {
+  1 [label="1", peripheries=2]
+  }
+  subgraph cluster_1 {
   0 [label="0"]
+  }
   0 -> 1 [label="b"]
   0 -> 0 [label="0"]
-  1 [label="1", peripheries=2]
   1 -> 1 [label="1"]
 }
 EOF