You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: ft_filetype.m
    path of file: ./repos/cifti-matlab/ft_cifti/private
    
    the code of the file until where you have to start completion: function [type] = ft_filetype(filename, desired, va
    
function res = filetype_check_ascii(filename, len)
% See http://en.wikipedia.org/wiki/ASCII
if exist(filename, 'file')
  fid = fopen(filename, 'rt');
  bin = fread(fid, len, 'uint8=>uint8');
  fclose(fid);
  printable = bin>31 & bin<127;  % the printable characters, represent letters, digits, punctuation marks, and a few miscellaneous symbols
  special   = bin==10 | bin==13 | bin==11; % line feed, form feed, tab
  res = all(printable | special);
else
  % always return true if the file does not (yet) exist, this is important
  % for determining the format to which data should be written
  res = 1;
end