size_t *save_idx, struct substring *token);
void ds_rpad (struct string *, size_t length, char pad);
void ds_set_length (struct string *, size_t new_length, char pad);
size_t *save_idx, struct substring *token);
void ds_rpad (struct string *, size_t length, char pad);
void ds_set_length (struct string *, size_t new_length, char pad);