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Regex membership (#7506)

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* Make finding a word in the regex iterative

* Fixed gc problem
This commit is contained in:
Clemens Eisenhofer 2025-01-12 02:41:37 +01:00 • committed by GitHub
parent 9a237d55ca
commit c572fc2e4f
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GPG key ID: B5690EEEBB952194
5 changed files with 103 additions and 169 deletions
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90
src/ast/sls/sls_seq_plugin.cpp
View file

@ -1847,7 +1847,7 @@ namespace sls {
{
zstring s1;
if (ctx.is_true(e) && some_string_in_re(y, s1)) {
if (ctx.is_true(e) && rw.some_string_in_re(y, s1)) {
m_str_updates.push_back({ x, s1, 1 });
return apply_update();
}
@ -2001,92 +2001,4 @@ namespace sls {
choose(r2, k - 1, prefix2, result);
}
}
//
// Find some string that is a member of regex
//
bool seq_plugin::some_string_in_re(expr* _r, zstring& s) {
expr_ref r(_r, m);
seq_rewriter rw(m);
while (true) {
if (seq.re.is_empty(r))
return false;
auto info = seq.re.get_info(r);
if (info.nullable == l_true)
return true;
expr_ref r2 = rw.mk_derivative(r);
if (!append_char(r, r2, s))
return false;
r = r2;
}
}
bool seq_plugin::get_bounds(expr* e, unsigned& low, unsigned& high) {
// TODO: remove recursion (though it is probably not deep anyway)
expr* x, * y;
unsigned ch = 0;
if (m.is_and(e, x, y)) {
if (!get_bounds(x, low, high))
return false;
return get_bounds(y, low, high);
}
if (m.is_eq(e, x, y)) {
if ((is_var(x) && seq.is_const_char(y, ch)) || (is_var(y) && seq.is_const_char(x, ch))) {
if (ch < low || ch > high)
return false;
low = high = ch;
return true;
}
return false;
}
if (seq.is_char_le(e, x, y)) {
if (seq.is_const_char(x, ch)) {
low = std::max(ch, low);
return high >= low;
}
if (seq.is_const_char(y, ch)) {
high = std::min(ch, high);
return high >= low;
}
return false;
}
return false;
}
bool seq_plugin::append_char(expr* r0, expr_ref& r, zstring& s) {
expr* c, * th, * el;
if (seq.re.is_union(r)) {
auto info0 = seq.re.get_info(r0);
for (expr* r1 : *to_app(r)) {
auto info1 = seq.re.get_info(r1);
if (r0 == r1)
continue;
if (info1.min_length < info0.min_length) {
r = r1;
return append_char(r0, r, s);
}
}
expr* r2;
do {
r2 = to_app(r)->get_arg(ctx.rand(to_app(r)->get_num_args()));
} while (r2 == r0);
r = r2;
// Just take one that is not a self loop (there is always such one element)
return append_char(r0, r, s);
}
if (m.is_ite(r, c, th, el)) {
unsigned low = 0, high = UINT_MAX;
if (get_bounds(c, low, high)) {
SASSERT(low <= high);
s += zstring(low);
r = th;
return true;
}
verbose_stream() << "nyi append_char " << mk_bounded_pp(r, m) << "\n";
NOT_IMPLEMENTED_YET();
return false;
}
s += zstring(m_chars[ctx.rand(m_chars.size())]);
return true;
}
}

3
src/ast/sls/sls_seq_plugin.h
View file

@ -147,9 +147,6 @@ namespace sls {
void next_char(expr* r, unsigned_vector& chars);
bool is_in_re(zstring const& s, expr* r);
bool some_string_in_re(expr* r, zstring& s);
bool get_bounds(expr* e, unsigned& low, unsigned& high);
bool append_char(expr* r0, expr_ref& r, zstring& s);
// access evaluation
bool is_seq_predicate(expr* e);