struct regexp *
regexp_minus(struct info *info, struct regexp *r1, struct regexp *r2) {
const char *p1 = r1->pattern->str;
const char *p2 = r2->pattern->str;
struct regexp *result = NULL;
struct fa *fa = NULL, *fa1 = NULL, *fa2 = NULL;
int r;
char *s = NULL;
size_t s_len;
r = fa_compile(p1, strlen(p1), &fa1);
if (r != REG_NOERROR)
goto error;
r = fa_compile(p2, strlen(p2), &fa2);
if (r != REG_NOERROR)
goto error;
fa = fa_minus(fa1, fa2);
if (fa == NULL)
goto error;
r = fa_as_regexp(fa, &s, &s_len);
if (r < 0)
goto error;
if (s == NULL) {
/* FA is the empty set, which we can't represent as a regexp */
goto error;
}
result = make_regexp(info, s);
s = NULL;
done:
fa_free(fa);
fa_free(fa1);
fa_free(fa2);
free(s);
return result;
error:
unref(result, regexp);
goto done;
}
struct regexp *
regexp_minus(struct info *info, struct regexp *r1, struct regexp *r2) {
struct regexp *result = NULL;
struct fa *fa = NULL, *fa1 = NULL, *fa2 = NULL;
int r;
char *s = NULL;
size_t s_len;
fa1 = regexp_to_fa(r1);
ERR_BAIL(r1->info);
fa2 = regexp_to_fa(r2);
ERR_BAIL(r2->info);
fa = fa_minus(fa1, fa2);
if (fa == NULL)
goto error;
r = fa_as_regexp(fa, &s, &s_len);
if (r < 0)
goto error;
if (s == NULL) {
/* FA is the empty set, which we can't represent as a regexp */
goto error;
}
if (regexp_c_locale(&s, NULL) < 0)
goto error;
result = make_regexp(info, s, fa_is_nocase(fa));
s = NULL;
done:
fa_free(fa);
fa_free(fa1);
fa_free(fa2);
free(s);
return result;
error:
unref(result, regexp);
goto done;
}
