Refactor `mrb_string_value_cstr`
Keep `MRB_STR_ASCII` flag.
Avoid a string object creation.
MODIFY
src/string.c
src/string.c
@@ -245,6 +245,28 @@ str_decref(mrb_state *mrb, mrb_shared_string *shared)
}
}
+static void
+str_modify_keep_ascii(mrb_state *mrb, struct RString *s)
+{
+ if (RSTR_SHARED_P(s)) {
+ mrb_shared_string *shared = s->as.heap.aux.shared;
+
+ if (shared->refcnt == 1 && s->as.heap.ptr == shared->ptr) {
+ s->as.heap.aux.capa = shared->capa;
+ s->as.heap.ptr[s->as.heap.len] = '\0';
+ RSTR_UNSET_SHARED_FLAG(s);
+ mrb_free(mrb, shared);
+ }
+ else {
+ str_init_modifiable(mrb, s, s->as.heap.ptr, (size_t)s->as.heap.len);
+ str_decref(mrb, shared);
+ }
+ }
+ else if (RSTR_NOFREE_P(s) || RSTR_FSHARED_P(s)) {
+ str_init_modifiable(mrb, s, s->as.heap.ptr, (size_t)s->as.heap.len);
+ }
+}
+
static void
check_null_byte(mrb_state *mrb, mrb_value str)
{
@@ -814,23 +836,7 @@ MRB_API void
mrb_str_modify_keep_ascii(mrb_state *mrb, struct RString *s)
{
mrb_check_frozen(mrb, s);
- if (RSTR_SHARED_P(s)) {
- mrb_shared_string *shared = s->as.heap.aux.shared;
-
- if (shared->refcnt == 1 && s->as.heap.ptr == shared->ptr) {
- s->as.heap.aux.capa = shared->capa;
- s->as.heap.ptr[s->as.heap.len] = '\0';
- RSTR_UNSET_SHARED_FLAG(s);
- mrb_free(mrb, shared);
- }
- else {
- str_init_modifiable(mrb, s, s->as.heap.ptr, (size_t)s->as.heap.len);
- str_decref(mrb, shared);
- }
- }
- else if (RSTR_NOFREE_P(s) || RSTR_FSHARED_P(s)) {
- str_init_modifiable(mrb, s, s->as.heap.ptr, (size_t)s->as.heap.len);
- }
+ str_modify_keep_ascii(mrb, s);
}
MRB_API void
@@ -2423,15 +2429,12 @@ mrb_string_value_cstr(mrb_state *mrb, mrb_value *ptr)
if (p[len] == '\0') {
return p;
}
- if (mrb_frozen_p(ps) || RSTR_CAPA(ps) == len) {
- ps = str_new(mrb, NULL, len+1);
- memcpy(RSTR_PTR(ps), p, len);
- RSTR_SET_LEN(ps, len);
- *ptr = mrb_obj_value(ps);
- }
- else {
- mrb_str_modify(mrb, ps);
- }
+
+ /*
+ * Even after str_modify_keep_ascii(), NULL termination is not ensured if
+ * RSTR_SET_LEN() is used explicitly (e.g. String#delete_suffix!).
+ */
+ str_modify_keep_ascii(mrb, ps);
RSTR_PTR(ps)[len] = '\0';
return RSTR_PTR(ps);
}

Refactor `mrb_string_value_cstr`

- Keep `MRB_STR_ASCII` flag.
- Avoid a string object creation.