load_ext_trigger_data.m

function ext_trigger=load_ext_trigger_data(filename) 
% ext_trigger_data = load_ext_trigger_data(filename)
%
% Loads data from files generated by the StreamLogger consumer for EventExtTrigger
% events [ts,x,y,p,id].
% timestamps are in uS
% ext_trigger is a structure containing the fields ts, x, y, p and id

f=fopen(filename);

% Parse header if any
header = [];
endOfHeader = 0;
numCommentLine = 0;
while (endOfHeader==0)
    bod = ftell(f);
    tline = fgets(f,256);
    if(tline(1)~='%')
        endOfHeader = 1;
    else
        words = strsplit(tline);
        if (length(words) > 2 )
            if (strcmp(words{2} , 'Date'))
                if (length(words) > 3)
                    header = [header; {words{2}, horzcat(words{3}, ' ', words{4})}];
                end
            else
                header = [header; {words{2}, words{3}}];
            end
        end
        numCommentLine = numCommentLine+1;
    end
end
fseek(f,bod,'bof');

evType = 0;
evSize = 8;
if (numCommentLine>0) % Ensure compatibility with previous files.
    % Read event type
    evType = fread(f,1,'char');
    % Read event size
    evSize = fread(f,1,'char');
end


bof=ftell(f);

fseek(f,0,'eof');
numEvents=floor((ftell(f)-bof)/evSize);

% read data
fseek(f,bof,'bof'); % start just after header
allTs=uint32(fread(f,numEvents,'uint32',evSize-4,'l')); % ts are 4 bytes (uint32) skipping 4 bytes after each
fseek(f,bof+4,'bof'); % timestamps start 4 after bof
allAddr=uint32(fread(f,numEvents,'uint32',evSize-4,'l')); % addr are each 4 bytes (uint32) separated by 4 byte timestamps

fclose(f);

ext_trigger.ts = double(allTs);

polmask = hex2dec('000000F');
idmask = hex2dec('FC00000');

polshift=0; % bits to shift p to right
idshift=26;

addr=abs(allAddr); % make sure non-negative or an error will result from bitand (glitches can somehow result in negative addresses...)
ext_trigger.p=-1+2*double(bitshift(bitand(addr,polmask),-polshift)); % 1 for ON, -1 for OFF
ext_trigger.id=double(bitshift(bitand(addr,idmask),-idshift)); % id addresses
end