source: aedes_getdataformat.m

function dataformat = aedes_getdataformat(filename)
% AEDES_GETDATAFORMAT - Try to determine the data format of a file
%
%
% Synopsis:
%       dataformat=aedes_getdataformat(filename);
%
% Description:
%       Returns an identifier string corresponding to the data format of
%       the file FILENAME. If the data format cannot be determined, an
%       empty string is returned.
%
%       The possible identifier strings are:
%
%       'vnmr'        <-> Varian FID-file
%       'bruker_raw'  <-> Bruker FID-file
%       'bruker_reco' <-> Bruker reconstructed 2dseq file
%       'nifti'       <-> NIfTI or Analyze 7.5 format file
%       'sur'         <-> S.M.I.S. SUR-File
%       'dcm'         <-> DICOM File
%       'spect/ct'    <-> Gamma Medica SPECT/CT File
%       'mat'         <-> Matlab MAT-File
%       'roi'         <-> Aedes ROI-File
%       'fdf'         <-> Varian FDF-File
%
% Examples:
%
% See also:
%       AEDES, AEDES_DATA_READ

% This function is a part of Aedes - A graphical tool for analyzing
% medical images
%
% Copyright (C) 2006 Juha-Pekka Niskanen <Juha-Pekka.Niskanen@uku.fi>
%
% Department of Physics, Department of Neurobiology
% University of Kuopio, FINLAND
%
% This program may be used under the terms of the GNU General Public
% License version 2.0 as published by the Free Software Foundation
% and appearing in the file LICENSE.TXT included in the packaging of
% this program.
%
% This program is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
% WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.

% Check number of arguments
if nargin==0
        error('Too few input arguments')
elseif nargin>1
        error('Too many input arguments')
end

dataformat = '';

[f_path,f_name,f_ext] = fileparts(filename);
if isempty(f_path)
        f_path = [pwd,filesep];
else
        f_path=[f_path,filesep];
end

% Check if is gzipped NIfTI
if strcmpi(f_ext,'.gz') && length(f_name)>3 && ...
                strcmpi(f_name(end-3:end),'.nii')
        f_name = f_name(1:length(f_name)-4);
        f_ext = '.nii.gz';
end

if isempty(f_ext)
        if strcmpi(f_name,'fid')
                % Check if the file is a Bruker or Varian FID file
                if exist([f_path,'procpar'],'file') == 2
                        dataformat = 'vnmr';
                else
                        dataformat = 'bruker_raw';
                end
                return
        elseif strcmpi(f_name,'2dseq')
                dataformat = 'bruker_reco';
                return
        else
                % Check if the file is a DICOM file which can many times be without
                % file extension
                fid = fopen(filename,'r');
                if fid < 0
                        return
                end
                
                % Seek over the possible DICOM preamble
                status = fseek(fid,128,-1);
                if status == -1
                        % Unknown data format
                        fclose(fid);
                        return
                end
                
                % Try to read the 4 byte DICOM prefix
                [str,count] = fread(fid,4,'char');
                if count~=4
                        fclose(fid);
                        return
                end
                str = char(str.');
                if strcmp(str,'DICM')
                        dataformat = 'dcm';
                end
                fclose(fid);
                return
        end
elseif strcmpi(f_ext,'.fid')
        dataformat = 'vnmr';
else
        if strcmpi(f_ext,'.xxm')
                dataformat='spect/ct';
        elseif any(strcmpi(f_ext,{'.nii','.nii.gz','.hdr','.img'}))
                dataformat = 'nifti';
                if strcmpi(f_ext,'.hdr')
                        % Check if data is in Analyze/NIfTI or SPECT/CT format
                        
                        % Try to open the file for reading
                        fid = fopen(filename,'r');
                        if fid<0
                                return
                        end
                        
                        % Read 10 characters from the start
                        [ident_str,count] = fread(fid,10,'char');
                        if count~=10
                                dataformat = '';
                                fclose(fid);
                                return
                        end
                        
                        if strcmp(char(ident_str).','!INTERFILE')
                                dataformat = 'spect/ct';
                        else
                                dataformat = 'nifti';
                        end
                end
        elseif any(strcmpi(f_ext(2:end),...
                        {'t1r','s1r','t2r','s2r','t1','t2','s1','s2','df','sf','r2','b1'}))
                % This file is probably Matlab MAT-file but could also be in the old
                % S.M.I.S. SUR-Format...
                fid = fopen(filename,'r');
                if fid < 0
                        return
                end
                
                % The first 6 characters in MAT-File should be MATLAB
                [str,count]=fread(fid,6,'char');
                if count~=6
                        fclose(fid);
                        return
                end
                str = char(str).';
                if strcmpi(str,'MATLAB')
                        dataformat = 'mat';
                else
                        dataformat = 'sur';
                end
        elseif strcmpi(f_ext,'.sgl')
                dataformat = 'swift_sgl';
        else
                dataformat = lower(f_ext(2:end)); % Remove the dot
                
                % Check if file is a DICOM file
                fid = fopen(filename,'r');
                if fid < 0
                        return
                end
                
                % Seek over the possible DICOM preamble
                status = fseek(fid,128,-1);
                if status == -1
                        % Unknown data format
                        fclose(fid);
                        return
                end
                
                % Read the 4 byte DICOM prefix
                [str,count] = fread(fid,4,'char');
                fclose(fid);
                if count~=4
                        return
                end
                str = char(str.');
                if strcmp(str,'DICM')
                        dataformat = 'dcm';
                end
                
        end
        
        
end