We request the function which can extract string based on byte .
Why this function requested is we would like to handle fixed byte file.
And file's column is decided based on byte size.
Basically we can handle this case by using substring method, but some language character has 2~3 byte per 1 character.
If data contains mixed characters such like double byte character and single byte character, substring cannot extract character based on byte.
So kindly please take it consider to create this kind of function.