shf_fillbuf
static int shf_fillbuf ARGS((struct shf *shf));
&& (shf_fillbuf(shf) == EOF || shf->rnleft == 0))
if (shf_fillbuf(shf) == EOF)
if (shf->rnleft == 0 && (shf_fillbuf(shf) == EOF || shf->rnleft == 0))