"without carriage return in line separators"

How have you implemented this? That is really trivial. Well compared to writing a text editor. I say this as the author of several failed text editors, so I'm not suggesting you lack the skills.

Carriage returns get filtered out when loading files, so the in memory representation always only has line feeds. And when saving it just save the in memory representation (so UTF-8 and with line feeds). I haven't added support for saving it with the original encoding and line endings because I never needed it, but yeah that should be easy to add. But for the internal representation I would probably still only use line feeds because supporting carriage returns in there would make some things more complex