Your code crashes when you get 32 bytes,.... because of how you treat it as a C string of the same length so it's not nul terminated when reading the whole 32

You should use the return value or read() not just to check for <0 (and thus not need the \0 filling either, also note that \0 is possible/valid in the terminal stream)

Also the big switch that sets every ascii code to… the same value is very unnecessary

(repeating from discord where this might have been lost)