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add (disabled) stubs for decomposing re-membership on regex

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Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
This commit is contained in:
Nikolaj Bjorner 2020-05-31 12:25:21 -07:00
parent 7f7663a3b4
commit 084cd335eb
4 changed files with 143 additions and 19 deletions
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82
src/ast/seq_decl_plugin.cpp
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@ -1155,6 +1155,13 @@ bv_util& seq_util::bv() const {
return *m_bv.get();
}
unsigned seq_util::max_plus(unsigned x, unsigned y) const {
if (x + y < x || x + y < y)
return UINT_MAX;
return x + y;
}
bool seq_util::is_const_char(expr* e, unsigned& c) const {
#if Z3_USE_UNICODE
return is_app_of(e, m_fid, OP_CHAR_CONST) && (c = to_app(e)->get_parameter(0).get_int(), true);
@ -1243,15 +1250,49 @@ app* seq_util::str::mk_is_empty(expr* s) const {
return m.mk_eq(s, mk_empty(get_sort(s)));
}
unsigned seq_util::str::min_length(expr* s) const {
SASSERT(u.is_seq(s));
expr_ref_vector es(m);
unsigned result = 0;
get_concat_units(s, es);
for (expr* arg : es) {
if (is_unit(arg))
result++;
expr* s1 = nullptr, *s2 = nullptr;
auto get_length = [&](expr* s1) {
zstring st;
if (is_unit(s1))
return 1u;
else if (is_string(s1, st))
return st.length();
else
return 0u;
};
while (is_concat(s, s1, s2)) {
result += get_length(s1);
s = s2;
}
result += get_length(s);
return result;
}
unsigned seq_util::str::max_length(expr* s) const {
SASSERT(u.is_seq(s));
unsigned result = 0;
expr* s1 = nullptr, *s2 = nullptr;
zstring st;
auto get_length = [&](expr* s1) {
if (is_empty(s1))
return 0u;
else if (is_unit(s1))
return 1u;
else if (is_string(s1, st))
return st.length();
else
return UINT_MAX;
};
while (is_concat(s, s1, s2)) {
result = u.max_plus(get_length(s), result);
s = s2;
}
result = u.max_plus(get_length(s), result);
return result;
}
@ -1260,15 +1301,8 @@ unsigned seq_util::re::min_length(expr* r) const {
expr* r1 = nullptr, *r2 = nullptr, *s = nullptr;
if (is_empty(r))
return UINT_MAX;
if (is_concat(r, r1, r2)) {
unsigned l1 = min_length(r1);
if (l1 == UINT_MAX)
return l1;
unsigned l2 = min_length(r2);
if (l2 == UINT_MAX)
return l2;
return l1 + l2;
}
if (is_concat(r, r1, r2))
return u.max_plus(min_length(r1), min_length(r2));
if (m.is_ite(r, s, r1, r2))
return std::min(min_length(r1), min_length(r2));
if (is_diff(r, r1, r2))
@ -1282,6 +1316,26 @@ unsigned seq_util::re::min_length(expr* r) const {
return 0;
}
unsigned seq_util::re::max_length(expr* r) const {
SASSERT(u.is_re(r));
expr* r1 = nullptr, *r2 = nullptr, *s = nullptr;
if (is_empty(r))
return 0;
if (is_concat(r, r1, r2))
return u.max_plus(max_length(r1), max_length(r2));
if (m.is_ite(r, s, r1, r2))
return std::max(max_length(r1), max_length(r2));
if (is_diff(r, r1, r2))
return max_length(r1);
if (is_union(r, r1, r2))
return std::max(max_length(r1), max_length(r2));
if (is_intersection(r, r1, r2))
return std::min(max_length(r1), max_length(r2));
if (is_to_re(r, s))
return u.str.max_length(s);
return UINT_MAX;
}
sort* seq_util::re::to_seq(sort* re) {
(void)u;
SASSERT(u.is_re(re));