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Support + and ? in construct_nfa()

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This commit is contained in:
Camden Dixie O'Brien 2024-11-03 12:16:38 +00:00
parent 1fea81b74b
commit e283fd2c52
2 changed files with 83 additions and 14 deletions
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49
lib/construct.c
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@ -128,19 +128,6 @@ static void construct_symbol(fsa_t *out, int symbol)
fsa_add_rule(out, out->initial, 0, symbol);
}
static void construct_star(fsa_t *out)
{
fsa_t f;
memcpy(&f, out, sizeof(fsa_t));
construct_symbol(out, EPSILON);
int f_initial, f_final;
add_fsa(out, &f, &f_initial, &f_final);
fsa_add_rule(out, out->initial, f_initial, EPSILON);
fsa_add_rule(out, f_final, f_initial, EPSILON);
fsa_add_rule(out, f_final, 0, EPSILON);
}
static bool in_class(const regex_class_t *class, char c)
{
for (int i = 0; i < class->count; ++i) {
@ -171,6 +158,38 @@ static void construct_wildcard(fsa_t *out)
fsa_add_rule(out, out->initial, 0, i);
}
static void base_quantify(fsa_t *out, int *init_out, int *final_out)
{
fsa_t f;
memcpy(&f, out, sizeof(fsa_t));
construct_base(out);
add_fsa(out, &f, init_out, final_out);
fsa_add_rule(out, out->initial, *init_out, EPSILON);
fsa_add_rule(out, *final_out, 0, EPSILON);
}
static void construct_star(fsa_t *out)
{
int sub_init, sub_final;
base_quantify(out, &sub_init, &sub_final);
fsa_add_rule(out, sub_final, sub_init, EPSILON);
fsa_add_rule(out, out->initial, 0, EPSILON);
}
static void construct_plus(fsa_t *out)
{
int sub_init, sub_final;
base_quantify(out, &sub_init, &sub_final);
fsa_add_rule(out, sub_final, sub_init, EPSILON);
}
static void construct_qmark(fsa_t *out)
{
int sub_init, sub_final;
base_quantify(out, &sub_init, &sub_final);
fsa_add_rule(out, out->initial, 0, EPSILON);
}
static void construct_term(const regex_term_t *term, fsa_t *out)
{
switch (term->type) {
@ -198,8 +217,10 @@ static void construct_term(const regex_term_t *term, fsa_t *out)
construct_star(out);
break;
case REGEX_QUANTIFIER_PLUS:
construct_plus(out);
break;
case REGEX_QUANTIFIER_QMARK:
assert(false);
construct_qmark(out);
break;
}

48
tests/construct_tests.c
View File

@ -181,6 +181,52 @@ static void test_star(void)
fsa_free(&fsa);
}
static void test_plus(void)
{
regex_term_t *terms = malloc(1 * sizeof(regex_term_t));
terms[0].quantifier = REGEX_QUANTIFIER_PLUS;
terms[0].type = REGEX_TERM_LITERAL;
terms[0].literal = 'a';
regex_sequence_t *alternatives = malloc(1 * sizeof(regex_sequence_t));
alternatives[0].count = alternatives[0].capacity = 1;
alternatives[0].contents = terms;
regex_t regex = { .count = 1, .capacity = 1, .contents = alternatives };
fsa_t fsa;
construct_nfa(&regex, &fsa);
ASSERT_TRUE(accepts(&fsa, "a"));
ASSERT_TRUE(accepts(&fsa, "aaaaaa"));
ASSERT_FALSE(accepts(&fsa, ""));
ASSERT_FALSE(accepts(&fsa, "b"));
regex_free(&regex);
fsa_free(&fsa);
}
static void test_qmark(void)
{
regex_term_t *terms = malloc(1 * sizeof(regex_term_t));
terms[0].quantifier = REGEX_QUANTIFIER_QMARK;
terms[0].type = REGEX_TERM_LITERAL;
terms[0].literal = 'a';
regex_sequence_t *alternatives = malloc(1 * sizeof(regex_sequence_t));
alternatives[0].count = alternatives[0].capacity = 1;
alternatives[0].contents = terms;
regex_t regex = { .count = 1, .capacity = 1, .contents = alternatives };
fsa_t fsa;
construct_nfa(&regex, &fsa);
ASSERT_TRUE(accepts(&fsa, ""));
ASSERT_TRUE(accepts(&fsa, "a"));
ASSERT_FALSE(accepts(&fsa, "aa"));
ASSERT_FALSE(accepts(&fsa, "b"));
regex_free(&regex);
fsa_free(&fsa);
}
static void test_subexpression(void)
{
regex_term_t *inner_terms = malloc(1 * sizeof(regex_term_t));
@ -415,6 +461,8 @@ int main(void)
test_sequence();
test_union();
test_star();
test_plus();
test_qmark();
test_subexpression();
test_class();
test_negated_class();