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- function [n, ts] = nex_ts(filename, varname)
- % nex_ts(filename, varname): Read timestamps from a .nex file
- %
- % [n, ts] = nex_ts(filename, varname)
- %
- % INPUT:
- % filename - if empty string, will use File Open dialog
- % varname - variable name
- % OUTPUT:
- % n - number of timestamps
- % ts - array of timestamps (in seconds)
- n = 0;
- ts = 0;
- if(nargin ~= 2)
- disp('2 input arguments are required')
- return
- end
- if(ischar(filename) == 0)
- disp('input arguments should be character arrays')
- return
- end
- if(ischar(varname) == 0)
- disp('input arguments should be character arrays')
- return
- end
- if(isempty(filename))
- [fname, pathname] = uigetfile('*.nex', 'Select a Nex file');
- filename = strcat(pathname, fname);
- end
- fid = fopen(filename, 'r');
- if(fid == -1)
- disp('cannot open file');
- return
- end
- disp(strcat('file = ', filename));
- magic = fread(fid, 1, 'int32');
- version = fread(fid, 1, 'int32');
- comment = fread(fid, 256, 'char');
- freq = fread(fid, 1, 'double');
- tbeg = fread(fid, 1, 'int32');
- tend = fread(fid, 1, 'int32');
- nvar = fread(fid, 1, 'int32');
- fseek(fid, 260, 'cof');
- name = zeros(1, 64);
- found = 0;
- for i=1:nvar
- type = fread(fid, 1, 'int32');
- var_version = fread(fid, 1, 'int32');
- name = fread(fid, [1 64], 'char');
- offset = fread(fid, 1, 'int32');
- n = fread(fid, 1, 'int32');
- name = char(name);
- name = deblank(name);
- k = strcmp(name, deblank(varname));
- if(k == 1)
- found = 1;
- fseek(fid, offset, 'bof');
- ts = fread(fid, [1 n], 'int32');
- break
- end
- dummy = fread(fid, 128, 'char');
- end
- fclose(fid);
- if found == 0
- disp('did not find variable in the file');
- else
- ts = ts/freq;
- disp(strcat('number of timestamps = ', num2str(n)));
- end
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