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: read_biff.m
    path of file: ./repos/malini/Codes/deconvolution - model/spm8/external/fieldtrip/fileio/private
    
    the code of the file until where you have to start completion: function [this] = read_biff(filename, opt)

% READ_BIFF reads data and header information from a BIFF file
%
% This is a attemt for a reference implementation to read the BIFF
% file format as defined by the Clinical Neurophysiology department of
% the University Medical Centre, Nijmegen.
%  
% read all data and information
%   [data]  = read_biff(filename)
% or read a selected top-level chunk
%   [chunk] = read_biff(filename, chunkID)
% 
% known top-level chunk id's are
%   data    : measured data         (matrix)
%   dati    : information on data       (struct)
%   expi    : information on experiment (struct)
%   pati    : information on patient    (struct)
%   evnt    : event markers         (struct)

% Copyright (C) 2000, Robert Oostenveld
% 
% This file is part of FieldTrip, see http://www.ru.nl/neuroimaging/fieldtrip
% for the documentation and details.
%
%    FieldTrip is free software: you can redistribute it and/or modify
%    it under the terms of the GNU General Public License as published by
%    the Free Software Foundation, either version 3 of the License, or
%    (at your option) any later version.
%
%    FieldTrip is distributed in the hope that it will be useful,
%    but WITHOUT ANY WARRANTY; without even the implied warranty of
%    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
%    GNU General Public License for more details.
%
%    You should have received a copy of the GNU General Public License
%    along with FieldTrip. If not, see <http://www.gnu.org/licenses/>.
%
% $Id: read_biff.m 7123 2012-12-06 21:21:38Z roboos $

define_biff;
this = [];

fid = fopen(filename, 'r');
fseek(fid,0,'eof');
eof = ftell(fid);

    
function [this] = read_biff(filename, opt)

% READ_BIFF reads data and header information from a BIFF file
%
% This is a attemt for a reference implementation to read the BIFF
% file format as defined by the Clinical Neurophysiology department of
% the University Medical Centre, Nijmegen.
%  
% read all data and information
%   [data]  = read_biff(filename)
% or read a selected top-level chunk
%   [chunk] = read_biff(filename, chunkID)
% 
% known top-level chunk id's are
%   data    : measured data         (matrix)
%   dati    : information on data       (struct)
%   expi    : information on experiment (struct)
%   pati    : information on patient    (struct)
%   evnt    : event markers         (struct)

% Copyright (C) 2000, Robert Oostenveld
% 
% This file is part of FieldTrip, see http://www.ru.nl/neuroimaging/fieldtrip
% for the documentation and details.
%
%    FieldTrip is free software: you can redistribute it and/or modify
%    it under the terms of the GNU General Public License as published by
%    the Free Software Foundation, either version 3 of the License, or
%    (at your option) any later version.
%
%    FieldTrip is distributed in the hope that it will be useful,
%    but WITHOUT ANY WARRANTY; without even the implied warranty of
%    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
%    GNU General Public License for more details.
%
%    You should have received a copy of the GNU General Public License
%    along with FieldTrip. If not, see <http://www.gnu.org/licenses/>.
%
% $Id: read_biff.m 7123 2012-12-06 21:21:38Z roboos $

define_biff;
this = [];

fid = fopen(filename, 'r');
fseek(fid,0,'eof');
eof = ftell(fid);
fseek(fid,0,'bof');

[id, siz] = chunk_header(fid);

switch id
  case 'SEMG'
    child  = subtree(BIFF, id);
    this   = read_biff_chunk(fid, id, siz, child);

  case 'LIST'
    fprintf('skipping unimplemented chunk id="%s" size=%4d\n', id, siz);

  case 'CAT '
    fprintf('skipping unimplemented chunk id="%s" size=%4d\n', id, siz);

  otherwise
    fprintf('skipping unrecognized chunk id="%s" size=%4d\n', id, siz);
    fseek(fid, siz, 'cof');

end