free_load_data(LoadData *ld) {
    free(ld->buf); ld->buf_used = 0; ld->buf_capacity = 0;
    ld->buf = NULL;

    if (ld->mapped_file) munmap(ld->mapped_file, ld->mapped_file_sz);
    ld->mapped_file = NULL; ld->mapped_file_sz = 0;
}