Function getbuff

3rd/lua-5.4.3/src/lobject.c:428–433

** Get a space of size 'sz' in the buffer. If buffer has not enough ** space, empty it. 'sz' must fit in an empty buffer. */

** space, empty it. 'sz' must fit in an empty buffer.
*/
static char *getbuff (BuffFS *buff, int sz) {
  lua_assert(buff->blen <= BUFVFS); lua_assert(sz <= BUFVFS);
  if (sz > BUFVFS - buff->blen)  /* not enough space? */
    clearbuff(buff);
  return buff->space + buff->blen;
}


#define addsize(b,sz)	((b)->blen += (sz))