Function tunpack

third-party/lua-5.5.0/src/ltablib.c:205–219

static int tunpack (lua_State *L) {
  lua_Unsigned n;
  lua_Integer i = luaL_optinteger(L, 2, 1);
  lua_Integer e = luaL_opt(L, luaL_checkinteger, 3, luaL_len(L, 1));
  if (i > e) return 0;  /* empty range */
  n = l_castS2U(e) - l_castS2U(i);  /* number of elements minus 1 */
  if (l_unlikely(n >= (unsigned int)INT_MAX  ||
                 !lua_checkstack(L, (int)(++n))))
    return luaL_error(L, "too many results to unpack");
  for (; i < e; i++) {  /* push arg[i..e - 1] (to avoid overflows) */
    lua_geti(L, 1, i);
  }
  lua_geti(L, 1, e);  /* push last element */
  return (int)n;
}

/* }====================================================== */