MATLAB load OceanView TXT files

load_oceanView.m

function [intensities, wavelengths, t] = load_oceanView(filesGlobString)
    %load_oceanVew 
    %   - output is INSTANTLY ready to be graphed
    %     via surf(t, wavelengths, intensities)
    %   - does NOT fail on data that's non-uniform in time
    %      e.g. when OceanView malfunctions

    files = matlab.buildtool.io.FileCollection.fromPaths( ...
        replace(filesGlobString,'/',filesep));
    paths = files.paths;
    n_records = length(paths);

    f = fopen(paths{1}); % if this fails your glob matched ZERO files, surely an accident
    tline = fgetl(f); %begin do-while
    while ischar(tline)

        m = regexp(tline, '^Number of Pixels in Spectrum: (\d+)', 'tokens', 'once');
        if ~isempty(m)
            n_lines = str2double(m{1});
            break;
        end

        tline = fgetl(f); %end do-while
    end
    fclose(f);

    intensities = zeros(n_lines, n_records);
    wavelengths = zeros(n_lines, n_records);
    timestamps = NaT(1, n_records);

    heuristics = nan(2, n_records);

    for i = 1:length(paths)
        fname = paths{i};
        f = fopen(fname);
        tline = fgetl(f); %begin do-while
        while ~strcmp(tline, '>>>>>Begin Spectral Data<<<<<')

            m = regexp(tline, '^Date: (.*?) ?(\w+)?( ?\d{4})$', 'tokens', 'once');
            if ~isempty(m)
                timestamp_str = append(m{1}, m{3});
                dst = ~isempty(regexp(m{2}, 'DT$', 'once'));
                d = datetime(timestamp_str, 'InputFormat','eee MMM dd HH:mm:ss yyyy');

                m = regexp(fname, sprintf("_%02d-%02d-%02d-(\\d{0,3})\\.txt$", hour(d), minute(d), second(d)), 'tokens', 'once');
                if ~isempty(m)
                    % timestamp filenames
                    heuristics(1,i) = str2double(m{1});
                else
                    m = regexp(fname, "_(\d+)\.txt$", 'tokens', 'once');
                    if ~isempty(m)
                        % serial filenames
                        heuristics(2,i) = str2double(m{1});
                    end
                end

                timestamps(i) = d - hours(dst); % I will be DAMNED if this code breaks during an experiment at 2am in November
            end

            tline = fgetl(f); %end do-while
        end

        for j = 1:n_lines
            row = textscan(f, "%f\t%f\n");
            wavelengths(j,i) = row{1};
            intensities(j,i) = row{2};
        end

        fclose(f);
    end

    heuristics_result = ~any(isnan(heuristics), 2)';
    if heuristics_result(1)
        timestamps = timestamps + milliseconds(heuristics(1,:));
        t = timestamps - min(timestamps);
    elseif heuristics_result(2)
        tmp = fit( ...
            heuristics(2,[1 end])', ...
            milliseconds(timestamps([1 end]) - min(timestamps))', ...
            'poly1');
        t = milliseconds(feval(tmp, heuristics(2,:))');
    else
        t = timestamps - min(timestamps);
    end

    [t, I] = sort(t, 'ascend'); % OS does not guarantee files will have been loaded in chronological order
    intensities = intensities(:,I);
    wavelengths = wavelengths(:,I);
end