#define OPT_EXTRA(f,bump) ((union file_extras*)(f) - file_extra_cnt - 1 - (bump))
#define LEN64_BUMP(f) ((f)->flags & FLAG_LENGTH64 ? 1 : 0)
#define OPT_EXTRA(f,bump) ((union file_extras*)(f) - file_extra_cnt - 1 - (bump))
#define LEN64_BUMP(f) ((f)->flags & FLAG_LENGTH64 ? 1 : 0)