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scc_info: make it possible to ignore or cut edges

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* spot/twaalgos/sccinfo.hh, spot/twaalgos/sccinfo.cc: Take
a filter function as optional argument.
* tests/core/sccif.cc, tests/core/sccif.test: New files.
* tests/Makefile.am, tests/core/.gitignore: Adjust.
* NEWS: Mention the new feature.
This commit is contained in:
Alexandre Duret-Lutz 2017-05-20 11:14:39 +02:00
parent 4da6a5cde1
commit 425620150a
7 changed files with 287 additions and 6 deletions
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45
spot/twaalgos/sccinfo.hh
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@ -277,12 +277,45 @@ namespace spot
// support that yet.
typedef scc_info_node scc_node;
typedef scc_info_node::scc_succs scc_succs;
/// @{
/// \brief An edge_filter may be called on each edge to decide what
/// to do with it.
///
/// The edge filter is called with an edge and a destination. (In
/// existential automata the destination is already given by the
/// edge, but in alternating automata, one edge may have several
/// destinations, and in this case the filter will be called for
/// each destination.) The filter should return a value from
/// edge_filter_choice.
///
/// \c keep means to use the edge normally, as if no filter had
/// been given. \c ignore means to pretend the edge does not
/// exist (if the destination is only reachable through this edge,
/// it will not be visited). \c cut also ignores the edge, but
/// it remembers to visit the destination state (as if it were an
/// initial state) in case it is not reachable otherwise.
///
/// Note that successors between SCCs can only be maintained for
/// edges that are kept. If some edges are ignored or cut, the
/// SCC graph that you can explore with scc_info::initial() and
/// scc_info::succ() will be restricted to the portion reachable
/// with "keep" edges. Additionally SCCs might be created when
/// edges are cut, but those will not be reachable from
/// scc_info::initial()..
enum class edge_filter_choice { keep, ignore, cut };
typedef edge_filter_choice
(*edge_filter)(const twa_graph::edge_storage_t& e, unsigned dst,
void* filter_data);
/// @}
protected:
std::vector<unsigned> sccof_;
std::vector<scc_node> node_;
const_twa_graph_ptr aut_;
unsigned initial_state_;
edge_filter filter_;
void* filter_data_;
// Update the useful_ bits. Called automatically.
void determine_usefulness();
@ -293,7 +326,13 @@ namespace spot
}
public:
scc_info(const_twa_graph_ptr aut);
// Use ~0U instead of -1U to work around a bug in Swig.
// See https://github.com/swig/swig/issues/993
scc_info(const_twa_graph_ptr aut,
unsigned initial_state = ~0U,
edge_filter filter = nullptr,
void* filter_data = nullptr);
const_twa_graph_ptr get_aut() const
{
@ -389,8 +428,8 @@ namespace spot
/// \brief Get number of the SCC containing the initial state.
unsigned initial() const
{
SPOT_ASSERT(scc_count() - 1 == scc_of(aut_->get_init_state_number()));
return scc_count() - 1;
SPOT_ASSERT(filter_ || scc_count() - 1 == scc_of(initial_state_));
return scc_of(initial_state_);
}
const scc_succs& succ(unsigned scc) const