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%      <>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> %
%      <                                                      > %
%      <                    DISCLAIMER:                       > %
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%      <  THIS PROGRAM IS INTENDED FOR RESEARCH PURPOSES ONLY. > %
%      <  THIS PROGRAM IS IN NO WAY INTENDED FOR CLINICAL OR   > %
%      <                    OFFICIAL USE.                     > %
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%      <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<> %
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function [data] = readmarkerfile(folder);
% function reads a CTF data file (.ds), Read 'markerfile.mrk'
% marker is the read-only 'markerfile.mrk'
% creates structure 'data' which contains number_markers, number_samples,
%       marker_names, trial_times, marker.


a = exist(fullfile(folder,'MarkerFile.mrk'));
if a == 0
   disp(' ');
   disp('Error: Your data could not be found. MarkerFile.mrk does not exist in this directory.');
   disp(' ');
   data = [];
   return
end   % error message if incorrect directory is displayed


markr =  textread(fullfile(folder,'MarkerFile.mrk'),'%s','delimiter','\n');
% creates markerfile.mrk in FOLDER directory. Type 'marker' to view.


number_markers_id = strmatch('NUMBER OF MARKERS:',markr,'exact');
markers = str2num(markr{number_markers_id+1});
% defines markers

name_id = strmatch('NAME:',markr,'exact');
names = markr(name_id+1);
% defines names

number_samples_id = strmatch('NUMBER OF SAMPLES:',markr,'exact');
samples = str2num(char(markr(number_samples_id+1)));
% defines samples
for i = 1:length(samples)
    if samples(i) == 0
	disp(['Warning: one of the markers, ' names{i} ', has zero samples.']);
    end
end

trial = strmatch('LIST OF SAMPLES',markr)+2;
for i = 1:markers
    trials{i} = str2num(char(markr(trial(i):trial(i)+samples(i))));
    if samples(i) ~= 0
	trials{i}(:,1) = trials{i}(:,1) + 1;
    end
end

data = struct('number_markers',{markers},'number_samples',{samples},'marker_names',{names},'trial_times',{trials});
% defines data