py/objstr: Add a helper to set mp_obj_str_t data.

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

py/objstr.c

@@ -2045,6 +2045,12 @@ mp_int_t mp_obj_str_get_buffer(mp_obj_t self_in, mp_buffer_info_t *bufinfo, mp_u
     }
 }
 
+void mp_obj_str_set_data(mp_obj_str_t *str, const byte *data, size_t len) {
+    str->data = data;
+    str->len = len;
+    str->hash = qstr_compute_hash(data, len);
+}
+
 // This locals table is used for the following types: str, bytes, bytearray, array.array.
 // Each type takes a different section (start to end offset) of this table.
 STATIC const mp_rom_map_elem_t array_bytearray_str_bytes_locals_table[] = {

py/objstr.h

@@ -94,6 +94,8 @@ mp_obj_t mp_obj_new_str_of_type(const mp_obj_type_t *type, const byte *data, siz
 mp_obj_t mp_obj_str_binary_op(mp_binary_op_t op, mp_obj_t lhs_in, mp_obj_t rhs_in);
 mp_int_t mp_obj_str_get_buffer(mp_obj_t self_in, mp_buffer_info_t *bufinfo, mp_uint_t flags);
 
+void mp_obj_str_set_data(mp_obj_str_t *str, const byte *data, size_t len);
+
 const byte *str_index_to_ptr(const mp_obj_type_t *type, const byte *self_data, size_t self_len,
     mp_obj_t index, bool is_slice);
 const byte *find_subbytes(const byte *haystack, size_t hlen, const byte *needle, size_t nlen, int direction);