STYLE
void forward(FILE *, enum STYLE, off_t, struct stat *);
void reverse(FILE *, enum STYLE, off_t, struct stat *);
forward(FILE *fp, enum STYLE style, off_t off, struct stat *sbp)
r_reg(FILE *fp, enum STYLE style, off_t off, struct stat *sbp)
static void r_reg(FILE *, enum STYLE, off_t, struct stat *);
reverse(FILE *fp, enum STYLE style, off_t off, struct stat *sbp)
enum STYLE style;