+
+ if (lua_gettop(L) > 2) {
+ int offset = luaL_optint(L, 3, 0);
+ if (offset) {
+ if (offset < len) {
+ data += offset;
+ len -= offset;
+ } else {
+ len = 0;
+ }
+ }
+
+ unsigned int wlen = luaL_optint(L, 4, len);
+ if (wlen < len) {
+ len = wlen;
+ }
+ }
+