Function luaD_growstack

lib/lua/src/ldo.c:242–269

** Try to grow the stack by at least 'n' elements. When 'raiseerror' ** is true, raises any error; otherwise, return 0 in case of errors. */

** is true, raises any error; otherwise, return 0 in case of errors.
*/
int luaD_growstack (lua_State *L, int n, int raiseerror) {
  int size = stacksize(L);
  if (l_unlikely(size > LUAI_MAXSTACK)) {
    /* if stack is larger than maximum, thread is already using the
       extra space reserved for errors, that is, thread is handling
       a stack error; cannot grow further than that. */
    lua_assert(stacksize(L) == ERRORSTACKSIZE);
    if (raiseerror)
      luaD_throw(L, LUA_ERRERR);  /* error inside message handler */
    return 0;  /* if not 'raiseerror', just signal it */
  }
  else if (n < LUAI_MAXSTACK) {  /* avoids arithmetic overflows */
    int newsize = 2 * size;  /* tentative new size */
    int needed = cast_int(L->top.p - L->stack.p) + n;
    if (newsize > LUAI_MAXSTACK)  /* cannot cross the limit */
      newsize = LUAI_MAXSTACK;
    if (newsize < needed)  /* but must respect what was asked for */
      newsize = needed;
    if (l_likely(newsize <= LUAI_MAXSTACK))
      return luaD_reallocstack(L, newsize, raiseerror);
  }
  /* else stack overflow */
  /* add extra size to be able to handle the error message */
  luaD_reallocstack(L, ERRORSTACKSIZE, raiseerror);
  if (raiseerror)
    luaG_runerror(L, "stack overflow");
  return 0;
}


/*