1 // -*- coding: utf-8 -*-
2 // Copyright (C) 2017-2021 Laboratoire de Recherche et Développement
3 // de l'Epita.
4 //
5 // This file is part of Spot, a model checking library.
6 //
7 // Spot is free software; you can redistribute it and/or modify it
8 // under the terms of the GNU General Public License as published by
9 // the Free Software Foundation; either version 3 of the License, or
10 // (at your option) any later version.
11 //
12 // Spot is distributed in the hope that it will be useful, but WITHOUT
13 // ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
14 // or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public
15 // License for more details.
16 //
17 // You should have received a copy of the GNU General Public License
18 // along with this program.  If not, see <http://www.gnu.org/licenses/>.
19 
20 #include "config.h"
21 #include <spot/twaalgos/split.hh>
22 #include <spot/misc/minato.hh>
23 #include <spot/misc/bddlt.hh>
24 #include <spot/priv/robin_hood.hh>
25 
26 #include <algorithm>
27 #include <map>
28 
29 namespace spot
30 {
split_edges(const const_twa_graph_ptr & aut)31   twa_graph_ptr split_edges(const const_twa_graph_ptr& aut)
32   {
33     twa_graph_ptr out = make_twa_graph(aut->get_dict());
34     out->copy_acceptance_of(aut);
35     out->copy_ap_of(aut);
36     out->prop_copy(aut, twa::prop_set::all());
37     out->new_states(aut->num_states());
38     out->set_init_state(aut->get_init_state_number());
39 
40     // We use a cache to avoid the costly loop around minterms_of().
41     // Cache entries have the form (id, [begin, end]) where id is the
42     // number of a BDD that as been (or will be) split, and begin/end
43     // denotes a range of existing transition numbers that cover the
44     // split.
45     typedef std::pair<unsigned, unsigned> cached_t;
46     robin_hood::unordered_map<unsigned, cached_t> split_cond;
47 
48     bdd all = aut->ap_vars();
49     internal::univ_dest_mapper<twa_graph::graph_t> uniq(out->get_graph());
50 
51     for (auto& e: aut->edges())
52       {
53         bdd cond = e.cond;
54         if (cond == bddfalse)
55           continue;
56         unsigned dst = e.dst;
57         if (aut->is_univ_dest(dst))
58           {
59             auto d = aut->univ_dests(dst);
60             dst = uniq.new_univ_dests(d.begin(), d.end());
61           }
62 
63         auto& [begin, end] = split_cond[cond.id()];
64         if (begin == end)
65           {
66             begin = out->num_edges() + 1;
67             for (bdd minterm: minterms_of(cond, all))
68               out->new_edge(e.src, dst, minterm, e.acc);
69             end = out->num_edges() + 1;
70           }
71         else
72           {
73             auto& g = out->get_graph();
74             for (unsigned i = begin; i < end; ++i)
75               out->new_edge(e.src, dst, g.edge_storage(i).cond, e.acc);
76           }
77       }
78     return out;
79   }
80 }
81