Article author here. You're correct. It's new code that's calling into old, unrefactored code. Hence the casts. convert_input() is new, string_convert_ext() is

Article author here. You're correct. It's new code that's calling into old, unrefactored code. Hence the casts. convert_input() is new, string_convert_ext() is old. As is mentioned in the article, I'm working on a refactoring of string_convert_ext() that will obviate the casting (and incidentally also some allocating).