ISI_read.m

function [ISIdata] = ISI_read(prmts)
% ISI_READ  Load ISI data
% Load trials from binary file generated by LabView IOS application.
%
% Notes on use:
%  If function reports an Out of Memory error, try enabling pixel binning
%  to reduce memory usage when the function runs.
%

% Changelog:
%  03/01/11 Modified from Pablo's code, engineered to match the output of
%           ISI_recordframes_piezo.vi. All data formats should be in 
%           little-endian. Linux may not read 8 byte spacers correctly.
%           Also converts int16 data to single, instead of double. MP
%  02/02/12 Modified to allow pixel binning during file read. PMK
%  02/10/12 Fixed reading files on Linux. PMK
%  03/26/12 Fixed reading files with non-integer trial durations. PMK

% Open file
ISIdata = [];
path2file = fullfile(prmts.path2dir,prmts.name);
fid = fopen(path2file);
if fid==-1
    error(['Failed to open ' path2file]);
    return;
end

% Get file size
fseek(fid, 0, 'eof');
nFileSize = ftell(fid);

% Return file position indicator to start of file
fseek(fid, 0, 'bof');

% Get file headers
thestarttime = fread(fid,4,'int32');
size_x = fread(fid, 1, 'int16');
size_y = fread(fid, 1, 'int16');
frame_rate = fread(fid,1,'int16');
bin_duration = fread(fid,1,'int16');

% Read trial duration
nsec = fread(fid,1,'uint16');
bit_depth1 = fread(fid,1,'int16');
fpos = ftell(fid);
ntrials = fread(fid,1,'int32');
%nFramesPerTrial = nsec*(frame_rate/bin_duration);
bin_duration_sec = bin_duration / frame_rate;
if ~isempty(prmts.Trials2Use)
    trial_range = sprintf('[%d %d]', prmts.Trials2Use(1), prmts.Trials2Use(end));
else
    trial_range = sprintf('[0 %d]', ntrials);
end

% Estimate frames/trial from file filesize and known header sizes
nFrameSize = size_x * size_y * 2; % bytes
nHeaderSize = 20 + (ntrials * 47); % each trial has headers of 47 bytes
nFramesPerTrial = int32((nFileSize-nHeaderSize) / nFrameSize / ntrials);

% Print file into to prompt
fprintf('\nFilename:\t\t%s\nTrials:\t\t\t%d\nFrame Rate:\t\t%d frames/s\nBin Duration:\t%d frames / %.2f s\nFrame Size:\t\t%dx%d px\nFrames/trial:\t%d\nBit Depth:\t\t%d\nTrial Duration:\t%d s\nTrials Used:\t%s\n',...
    prmts.name, ntrials, frame_rate, bin_duration, bin_duration_sec, size_x,size_y,nFramesPerTrial,bit_depth1,nsec,trial_range);

% Check that frames/trial estimate is consistent with header information
% Note: These numbers WILL deviate if the trial duration is non-integer.
%       In these cases, we will issue a warning to prompt.
if nFramesPerTrial ~= [nsec*(frame_rate/bin_duration)]
    disp(sprintf('Warning: Frames/trial estimated from filesize (%.0f) is different from that retrieved from file headers (%d)', nFramesPerTrial, nsec*(frame_rate/bin_duration)))
end

if ~prmts.DoLoad
    return
end

fseek(fid, 25-4, 0);

hWait = waitbar(0,'Loading frames...');

h2fig = findobj('Tag', 'ISIanalysisGUI_fig');%ensure function can stil be run w/o GUI
if ~isempty(h2fig);centerfig(hWait, h2fig);end
drawnow;

ISIdata.frameStack = cell(ntrials,(nsec*(frame_rate/bin_duration)));
size(ISIdata.frameStack);
for k = 1:ntrials
    % Read trial header
    intcheck = fread(fid,1,'int32');        % should be -9999
    if intcheck ~= -9999
        warning('intcheck does not return -9999 in ISI_read.m. Entering debugging mode.')
        keyboard
    end
    trial = fread(fid,1,'uint32');          % trial #, starting with 0
    stimnum = fread(fid,1,'int32');
    if isunix
        trial_times = fread(fid,24,'signed char');   % On Windows, specifying 'char' works, but not on Linux
    else
        trial_times = fread(fid,24,'char');   % On Windows, specifying 'char' works
    end
    fseek(fid, 25, 0);
    fseek(fid, -8, 0); % back up by 4 int16 because not writing array size, like earlier version.

    %for m = 1:((1/bin_duration_sec)*nsec)
    for m = 1:nFramesPerTrial
        mFrame = single([]);
        mFrame = single(fread(fid, [size_x size_y], prmts.precision));

        % Bin pixels
        if isfield(prmts, 'imgBin')
            if prod(prmts.imgBin) > 1
                mFrame = downsamp2d(mFrame, prmts.imgBin);
            end
        end
        
        % Assign 
        ISIdata.frameStack{k,m} = single([]);
        ISIdata.frameStack{k,m} = mFrame;
    end
    if ishandle(hWait)
        waitbar(k/ntrials, hWait)
    else
        error('File read aborted.');
    end
end

% Check that we have read the correct number of frames by verifying that
% we are at the end-of-file.
if nFileSize ~= ftell(fid)
    disp('Warning: Not all file data was read!')
end

close(hWait)
fclose(fid);

% Store parameters relevant for further analysis
ISIdata.ntrials = ntrials;
ISIdata.nsec = nsec;
ISIdata.frame_rate = frame_rate;
ISIdata.bin_duration = bin_duration;
ISIdata.nFramesPerTrial = nFramesPerTrial;

% Frame size
ISIdata.frameSizeYX = [size_y size_x];
if isfield(prmts, 'imgBin')
    if prod(prmts.imgBin) > 1
        ISIdata.frameSizeYX = ISIdata.frameSizeYX ./ prmts.imgBin;
    end
end

ISIdata.nPreStimFrames = (frame_rate./bin_duration) * prmts.preStimDurSec;
ISIdata.nStimFrames = (frame_rate./bin_duration) * prmts.stimDurSec;
ISIdata.nPostStimFrames = nFramesPerTrial - (ISIdata.nPreStimFrames + ISIdata.nStimFrames);

return