time   calls  line
                  1 function [fileType, openAction, loadAction, description] = finfo(filename, ext)
                  2 % FINFO Identify file type against standard file handlers on path
                  3 %
                  4 %       [TYPE, OPENCMD, LOADCMD, DESCR] = finfo(FILENAME)
                  5 %
                  6 %       TYPE - contains type for FILENAME or 'unknown'.
                  7 %
                  8 %       OPENCMD - contains command to OPEN or EDIT the FILENAME or empty if
                  9 %                 no handler is found or FILENAME is not readable.
                 10 %
                 11 %       LOADCMD - contains command to LOAD data from FILENAME or empty if
                 12 %                 no handler is found or FILENAME is not readable.
                 13 %
                 14 %       DESCR   - contains description of FILENAME or error message if
                 15 %                 FILENAME is not readable.
                 16 %
                 17 % See OPEN, LOAD
                 18 
                 19 %   Copyright 1984-2008 The MathWorks, Inc.
                 20 %   $Revision: 1.19.4.16 $  $Date: 2010/08/23 23:09:33 $
                 21 
             4   22 if ~ischar(filename) 
                 23     error(message('MATLAB:finfo:InvalidType'));
                 24 end
                 25 
             4   26 if exist(filename,'file') == 0 
                 27     error(message('MATLAB:finfo:FileNotFound', filename))
                 28 end
                 29 
             4   30 if nargin == 2 && ~ischar(ext) 
                 31     error(message('MATLAB:finfo:ExtensionMustBeAString'));
                 32 end
                 33 
                 34 % get file extension
             4   35 if nargin == 1 || isempty(ext) 
  0.13       4   36     [ext, description] = getExtension(filename); 
                 37 else
                 38     description = '';
                 39 end
             4   40 ext = lower(ext); 
                 41 
                 42 % rip leading . from ext
             4   43 if ~isempty(findstr(ext,'.')) 
  0.01       4   44     ext = strtok(ext,'.'); 
             4   45 end 
                 46 
                 47 % special case for .text files (textread will give false positive)
             4   48 if strcmp(ext,'text') 
                 49     ext = '';
                 50 end
                 51 
                 52 % check if open and load handlers exist
             4   53 openAction = ''; 
             4   54 loadAction = ''; 
                 55 
                 56 % this setup will not allow users to override the default EXTread behavior
             4   57 if ~isempty(ext) 
                 58     % known data formats go to uiimport and importdata
             4   59     if strncmp(ext, 'xls', 3)  ||  ...                               %Excel file extensions START with xls 
                 60         ~isempty(strmatch(ext, ...
                 61                                  {'avi', ...                      % movie files
                 62                                  'au' , 'snd', 'wav', ...         % audio files
                 63                                  'csv', 'dat', 'dlm', 'tab', ...  % text files
                 64                                   'wk1', ...                      % other worksheet files 
                 65                                  'im'}, ...                       % image files (see getExtension below)
                 66                          'exact'))
                 67         openAction = 'uiimport';
                 68         loadAction = 'importdata';
             4   69     else 
                 70         %special cases for DOC and PPT formats
             4   71         if strncmp(ext, 'doc', 3) 
                 72             openAction = 'opendoc';
             4   73         elseif strncmp(ext, 'ppt', 3) 
                 74             openAction = 'openppt';
             4   75         else 
                 76             % unknown data format, try to find handler on the path
  0.01       4   77             openAction = which(['open' ext]); 
             4   78             loadAction = which([ext 'read']); 
             4   79         end 
             4   80     end 
             4   81 end 
                 82 
             4   83 if ~isempty(openAction) || ~isempty(loadAction) 
                 84     fileType = ext;
             4   85 else 
             4   86     fileType = 'unknown'; 
             4   87 end 
                 88 
                 89 % rip path stuff off commands
             4   90 if ~isempty(openAction) 
                 91     [p,openAction] = fileparts(openAction);
                 92 end
             4   93 if ~isempty(loadAction) 
                 94     [p,loadAction] = fileparts(loadAction);
                 95 end
                 96 
                 97 % make nice description and validate file format
             4   98 if nargout == 4 && isempty(description) % only fetch descr if necessary 
             4   99     if (strncmp(ext, 'xls', 3)) 
                100         [status, description] = xlsfinfo(filename);
  0.01       4  101     elseif ~isempty(ext) && ~isempty(which([ext 'finfo'])) 
                102         [status, description] = feval([ext 'finfo'], filename);
             4  103     else 
                104         % no finfo for this file, give back contents
             4  105         fid = fopen(filename); 
             4  106         if fid > 0 
  0.04       4  107             description = fread(fid,1024*1024,'*char')'; 
             4  108             fclose(fid); 
                109         else
                110             description = 'File not found';
                111         end
             4  112         status = 'NotFound'; 
             4  113     end     
             4  114     if isempty(status) 
                115             % the file finfo util sez this is a bogus file.
                116             % return valid file type but empty actions
                117             openAction = '';
                118             loadAction = '';
                119             % generate failure message, used by IMPORTDATA
                120             description = 'FileInterpretError'; 
                121     end
             4  122 end 

Other subfunctions in this file are not included in this listing.