private static boolean renameWorld(String worldname, String newname) {
if (isLoaded(worldname)) return false;
Tag t = getData(worldname);
if (t == null) return false;
t = t.findTagByName("Data");
if (t == null || t.getType() != Type.TAG_Compound) return false;
int i = 0;
for (Tag tt : (Tag[]) t.getValue()) {
if (tt.getName().equals("LevelName")) {
t.removeTag(i);
t.insertTag(new Tag(Type.TAG_String, "LevelName", newname), i);
break;
}
i++;
}
return setData(worldname, t);
}
