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automata
Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
This commit is contained in:
Nikolaj Bjorner
parent
4a5b645d88
commit
31302ec851
7 changed files with 386 additions and 134 deletions
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@ -25,6 +25,89 @@ Notes:
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#include"automaton.h"
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re2automaton::re2automaton(ast_manager& m): m(m), u(m) {}
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eautomaton* re2automaton::operator()(expr* e) {
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eautomaton* r = re2aut(e);
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if (r) {
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r->compress();
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}
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return r;
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}
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eautomaton* re2automaton::re2aut(expr* e) {
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SASSERT(u.is_re(e));
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expr* e1, *e2;
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scoped_ptr<eautomaton> a, b;
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if (u.re.is_to_re(e, e1)) {
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return seq2aut(e1);
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}
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else if (u.re.is_concat(e, e1, e2) && (a = re2aut(e1)) && (b = re2aut(e2))) {
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return eautomaton::mk_concat(*a, *b);
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}
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else if (u.re.is_union(e, e1, e2) && (a = re2aut(e1)) && (b = re2aut(e2))) {
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return eautomaton::mk_union(*a, *b);
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}
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else if (u.re.is_star(e, e1) && (a = re2aut(e1))) {
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a->add_final_to_init_moves();
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a->add_init_to_final_states();
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return a.detach();
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}
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else if (u.re.is_plus(e, e1) && (a = re2aut(e1))) {
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a->add_final_to_init_moves();
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return a.detach();
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}
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else if (u.re.is_opt(e, e1) && (a = re2aut(e1))) {
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a = eautomaton::mk_opt(*a);
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return a.detach();
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}
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else if (u.re.is_range(e)) {
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}
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else if (u.re.is_loop(e)) {
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}
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#if 0
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else if (u.re.is_intersect(e, e1, e2)) {
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}
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else if (u.re.is_empty(e)) {
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}
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#endif
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return 0;
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}
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eautomaton* re2automaton::seq2aut(expr* e) {
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SASSERT(u.is_seq(e));
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zstring s;
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expr* e1, *e2;
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scoped_ptr<eautomaton> a, b;
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if (u.str.is_concat(e, e1, e2) && (a = seq2aut(e1)) && (b = seq2aut(e2))) {
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return eautomaton::mk_concat(*a, *b);
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}
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else if (u.str.is_unit(e, e1)) {
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return alloc(eautomaton, m, e1);
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}
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else if (u.str.is_empty(e)) {
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return eautomaton::mk_epsilon(m);
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}
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else if (u.str.is_string(e, s)) {
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unsigned init = 0;
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eautomaton::moves mvs;
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unsigned_vector final;
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final.push_back(s.length());
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for (unsigned k = 0; k < s.length(); ++k) {
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// reference count?
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mvs.push_back(eautomaton::move(m, k, k+1, u.str.mk_char(s, k)));
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}
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return alloc(eautomaton, m, init, final, mvs);
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}
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return 0;
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}
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br_status seq_rewriter::mk_app_core(func_decl * f, unsigned num_args, expr * const * args, expr_ref & result) {
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SASSERT(f->get_family_id() == get_fid());
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@ -159,11 +242,15 @@ br_status seq_rewriter::mk_seq_concat(expr* a, expr* b, expr_ref& result) {
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result = a;
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return BR_DONE;
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}
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if (m_util.str.is_concat(a, c, d) &&
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m_util.str.is_string(d, s1) && isc2) {
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// TBD concatenation is right-associative
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if (isc2 && m_util.str.is_concat(a, c, d) && m_util.str.is_string(d, s1)) {
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result = m_util.str.mk_concat(c, m_util.str.mk_string(s1 + s2));
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return BR_DONE;
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}
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if (isc1 && m_util.str.is_concat(b, c, d) && m_util.str.is_string(c, s2)) {
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result = m_util.str.mk_concat(m_util.str.mk_string(s1 + s2), d);
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return BR_DONE;
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}
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return BR_FAILED;
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}
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@ -398,7 +485,7 @@ br_status seq_rewriter::mk_seq_suffix(expr* a, expr* b, expr_ref& result) {
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result = m().mk_eq(m_util.str.mk_empty(m().get_sort(a)), a);
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return BR_REWRITE3;
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}
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// concatenation is left-associative, so a2, b2 are not concatenations
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// TBD concatenation is right-associative
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expr* a1, *a2, *b1, *b2;
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if (m_util.str.is_concat(a, a1, a2) &&
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m_util.str.is_concat(b, b1, b2) && a2 == b2) {
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@ -498,7 +585,108 @@ br_status seq_rewriter::mk_str_stoi(expr* a, expr_ref& result) {
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}
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return BR_FAILED;
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}
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void seq_rewriter::add_next(u_map<expr*>& next, unsigned idx, expr* cond) {
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expr* acc;
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if (m().is_true(cond) || !next.find(idx, acc)) {
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next.insert(idx, cond);
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}
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else {
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next.insert(idx, m().mk_or(cond, acc));
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}
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}
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bool seq_rewriter::is_sequence(expr* e, expr_ref_vector& seq) {
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zstring s;
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ptr_vector<expr> todo;
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expr *e1, *e2;
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todo.push_back(e);
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while (!todo.empty()) {
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e = todo.back();
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todo.pop_back();
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if (m_util.str.is_string(e, s)) {
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for (unsigned i = s.length(); i > 0; ) {
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--i;
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seq.push_back(m_util.str.mk_char(s, i));
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}
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}
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else if (m_util.str.is_empty(e)) {
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continue;
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}
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else if (m_util.str.is_unit(e)) {
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seq.push_back(e);
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}
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else if (m_util.str.is_concat(e, e1, e2)) {
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todo.push_back(e1);
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todo.push_back(e2);
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}
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else {
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return false;
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}
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}
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seq.reverse();
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return true;
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}
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br_status seq_rewriter::mk_str_in_regexp(expr* a, expr* b, expr_ref& result) {
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scoped_ptr<eautomaton> aut;
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expr_ref_vector seq(m());
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if (is_sequence(a, seq) && (aut = re2automaton(m())(b))) {
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expr_ref_vector trail(m());
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u_map<expr*> maps[2];
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bool select_map = false;
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expr_ref ch(m()), cond(m());
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eautomaton::moves mvs;
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maps[0].insert(aut->init(), m().mk_true());
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// is_accepted(a, aut) & some state in frontier is final.
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for (unsigned i = 0; i < seq.size(); ++i) {
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u_map<expr*>& frontier = maps[select_map];
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u_map<expr*>& next = maps[!select_map];
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select_map = !select_map;
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ch = seq[i].get();
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next.reset();
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u_map<expr*>::iterator it = frontier.begin(), end = frontier.end();
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for (; it != end; ++it) {
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mvs.reset();
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unsigned state = it->m_key;
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expr* acc = it->m_value;
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aut->get_moves_from(state, mvs, false);
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for (unsigned j = 0; j < mvs.size(); ++j) {
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eautomaton::move const& mv = mvs[j];
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if (m().is_value(mv.t()) && m().is_value(ch)) {
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if (mv.t() == ch) {
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add_next(next, mv.dst(), acc);
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}
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else {
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continue;
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}
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}
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else {
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cond = m().mk_eq(mv.t(), ch);
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if (!m().is_true(acc)) cond = m().mk_and(acc, cond);
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add_next(next, mv.dst(), cond);
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}
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}
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}
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}
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u_map<expr*> const& frontier = maps[select_map];
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u_map<expr*>::iterator it = frontier.begin(), end = frontier.end();
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expr_ref_vector ors(m());
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for (; it != end; ++it) {
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unsigned_vector states;
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bool has_final = false;
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aut->get_epsilon_closure(it->m_key, states);
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for (unsigned i = 0; i < states.size() && !has_final; ++i) {
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has_final = aut->is_final_state(states[i]);
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}
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if (has_final) {
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ors.push_back(it->m_value);
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}
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}
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result = mk_or(ors);
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return BR_REWRITE_FULL;
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}
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return BR_FAILED;
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}
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br_status seq_rewriter::mk_str_to_regexp(expr* a, expr_ref& result) {
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