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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;
}