py/objstr: Optimise mp_obj_new_str_from_vstr for known-safe strings.

The new `mp_obj_new_str_from_utf8_vstr` can be used when you know you
already have a unicode-safe string.

Signed-off-by: Jim Mussared <jim.mussared@gmail.com>

2 files changed, 3 insertions, 3 deletions

diff --git a/extmod/modujson.c b/extmod/modujson.c
index 57c50deec..4e992e224 100644
--- a/extmod/modujson.c
+++ b/extmod/modujson.c
@@ -67,7 +67,7 @@ STATIC mp_obj_t mod_ujson_dump_helper(size_t n_args, const mp_obj_t *pos_args, m
         vstr_t vstr;
         vstr_init_print(&vstr, 8, &print_ext.base);
         mp_obj_print_helper(&print_ext.base, pos_args[0], PRINT_JSON);
-        return mp_obj_new_str_from_vstr(&vstr);
+        return mp_obj_new_str_from_utf8_vstr(&vstr);
     } else {
         // dump(obj, stream)
         print_ext.base.data = MP_OBJ_TO_PTR(pos_args[1]);
@@ -103,7 +103,7 @@ STATIC mp_obj_t mod_ujson_dumps(mp_obj_t obj) {
     mp_print_t print;
     vstr_init_print(&vstr, 8, &print);
     mp_obj_print_helper(&print, obj, PRINT_JSON);
-    return mp_obj_new_str_from_vstr(&vstr);
+    return mp_obj_new_str_from_utf8_vstr(&vstr);
 }
 STATIC MP_DEFINE_CONST_FUN_OBJ_1(mod_ujson_dumps_obj, mod_ujson_dumps);
 
diff --git a/extmod/modure.c b/extmod/modure.c
index 59fbfddbf..799fef13b 100644
--- a/extmod/modure.c
+++ b/extmod/modure.c
@@ -373,7 +373,7 @@ STATIC mp_obj_t re_sub_helper(size_t n_args, const mp_obj_t *args) {
     vstr_add_strn(&vstr_return, subj.begin, subj.end - subj.begin);
 
     if (mp_obj_get_type(where) == &mp_type_str) {
-        return mp_obj_new_str_from_vstr(&vstr_return);
+        return mp_obj_new_str_from_utf8_vstr(&vstr_return);
     } else {
         return mp_obj_new_bytes_from_vstr(&vstr_return);
     }