WBUF_SIZE
#define WBUF_MASK(_i) ((_i)&(WBUF_SIZE-1))
char wbuf[WBUF_SIZE];
return (used >= WBUF_SIZE);
if (sz > (WBUF_SIZE - WBUF_MASK(cons->wc)))
sz = WBUF_SIZE - WBUF_MASK(cons->wc);
if ((cons->wp - cons->wc) < WBUF_SIZE)