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new regex automata start; add complexity estimation

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This commit is contained in:
Murphy Berzish 2017-12-04 18:05:00 -05:00
parent b581ab70ed
commit fbe8d1577e
7 changed files with 127 additions and 3 deletions
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105
src/smt/theory_str.cpp
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@ -6446,6 +6446,111 @@ namespace smt {
}
}
// saturating unsigned addition
unsigned inline _qadd(unsigned a, unsigned b) {
if (a == UINT_MAX || b == UINT_MAX) {
return UINT_MAX;
}
unsigned result = a + b;
if (result < a || result < b) {
return UINT_MAX;
}
return result;
}
// saturating unsigned multiply
unsigned inline _qmul(unsigned a, unsigned b) {
if (a == UINT_MAX || b == UINT_MAX) {
return UINT_MAX;
}
unsigned result = a * b;
if (result < a || result < b) {
return UINT_MAX;
}
return result;
}
unsigned theory_str::estimate_regex_complexity(expr * re) {
ENSURE(u.is_re(re));
expr * sub1;
expr * sub2;
if (u.re.is_to_re(re, sub1)) {
SASSERT(u.str.is_string(sub1));
zstring str;
u.str.is_string(sub1, str);
return str.length();
} else if (u.re.is_complement(re, sub1)) {
return estimate_regex_complexity_under_complement(sub1);
} else if (u.re.is_concat(re, sub1, sub2)) {
unsigned cx1 = estimate_regex_complexity(sub1);
unsigned cx2 = estimate_regex_complexity(sub2);
return _qadd(cx1, cx2);
} else if (u.re.is_union(re, sub1, sub2)) {
unsigned cx1 = estimate_regex_complexity(sub1);
unsigned cx2 = estimate_regex_complexity(sub2);
return _qadd(cx1, cx2);
} else if (u.re.is_star(re, sub1) || u.re.is_plus(re, sub1)) {
unsigned cx = estimate_regex_complexity(sub1);
return _qmul(2, cx);
} else if (u.re.is_range(re, sub1, sub2)) {
SASSERT(u.str.is_string(sub1));
SASSERT(u.str.is_string(sub2));
zstring str1, str2;
u.str.is_string(sub1, str1);
u.str.is_string(sub2, str2);
SASSERT(str1.length() == 1);
SASSERT(str2.length() == 1);
return 1 + str2[0] - str1[0];
} else if (u.re.is_full(re)) {
return 1;
} else {
TRACE("str", tout << "WARNING: unknown regex term " << mk_pp(re, get_manager()) << std::endl;);
return 1;
}
}
unsigned theory_str::estimate_regex_complexity_under_complement(expr * re) {
ENSURE(u.is_re(re));
expr * sub1;
expr * sub2;
if (u.re.is_to_re(re, sub1)) {
SASSERT(u.str.is_string(sub1));
zstring str;
u.str.is_string(sub1, str);
return str.length();
} else if (u.re.is_complement(re, sub1)) {
// Why don't we return the regular complexity here?
// We could, but this might be called from under another complemented subexpression.
// It's better to give a worst-case complexity.
return estimate_regex_complexity_under_complement(sub1);
} else if (u.re.is_concat(re, sub1, sub2)) {
unsigned cx1 = estimate_regex_complexity_under_complement(sub1);
unsigned cx2 = estimate_regex_complexity_under_complement(sub2);
return _qadd(_qmul(2, cx1), cx2);
} else if (u.re.is_union(re, sub1, sub2)) {
unsigned cx1 = estimate_regex_complexity_under_complement(sub1);
unsigned cx2 = estimate_regex_complexity_under_complement(sub2);
return _qmul(cx1, cx2);
} else if (u.re.is_star(re, sub1) || u.re.is_plus(re, sub1)) {
unsigned cx = estimate_regex_complexity_under_complement(sub1);
return _qmul(2, cx);
} else if (u.re.is_range(re, sub1, sub2)) {
SASSERT(u.str.is_string(sub1));
SASSERT(u.str.is_string(sub2));
zstring str1, str2;
u.str.is_string(sub1, str1);
u.str.is_string(sub2, str2);
SASSERT(str1.length() == 1);
SASSERT(str2.length() == 1);
return 1 + str2[0] - str1[0];
} else if (u.re.is_full(re)) {
return 1;
} else {
TRACE("str", tout << "WARNING: unknown regex term " << mk_pp(re, get_manager()) << std::endl;);
return 1;
}
}
/*
* strArgmt::solve_concat_eq_str()
* Solve concatenations of the form: