[Closed] Encoding Byte->Char

Hi all, how to change the encoding in the read text from a byte?
Function has bit.intAsChar, it seems there a problem in the proper encoding characters GBK2312
Or there is another solutions? I need to read from a file 256 bytes of text encoding GBk2312

fn ReadFixedString bstream fixedLen=
    (
        local str = ""
        for i = 1 to fixedLen do
        (
            local ch = ReadByte bstream #unsigned
            str += bit.intAsChar ch
            if ch == 0 then
            (
                SkipBytes bstream (fixedLen - i)
                exit
            )
        )
        str
    )

thanks