MATLAB Simulink Level 4 MAT truncated file fix

fixlevel4.m

% quick and dirty file fixer for MATLAB Simulink Level 4
%
% Limitations: only double, needs to support other types and complex data
% Limitations: cannot cut file when spurious, needs to append a dummy
% variable (dummy)
%
% Emanuele Ruffaldi
% 
% See: http://it.mathworks.com/help/pdf_doc/matlab/matfile_format.pdf
function fixlevel4(filename,dofix)
if dofix
    mode = 'r+b';
else
    mode = 'rb';
end
f=fopen([filename '.mat'], mode);
fseek(f,0,'eof'); % 
s = ftell(f); % file size
fseek(f,0,'bof');

while feof(f) == 0
    % 20 bytes header
    hp = ftell(f);
    h2=fread(f,5,'int32')';
    if isempty(h2)
        break
    end
    if length(h2) < 5
        disp('need to close file')
        if dofix
            fseek(f,hp,'bof');
            remainder = s-hp-5*4-5;
            contentsize = max(1,remainder);
            tmp = zeros(contentsize,1);
            
            h3 = [0,1,contentsize,0,5]; % dummy header 1 by contentsize
            fwrite(f,h3,'int32');
            fwrite(f,'dummy','uint8');  % name
            fwrite(f,tmp,'double');     % data
        end
        break
    end
    rows = h2(2);
    cols = h2(3);
    name = char(fread(f,h2(5),'uint8'))'
    itemsize = 8;
    if h2(1) ~= 0
        error('only double supported');
    end    
    if cols == 0
        p = ftell(f); % current position
        cols = floor((s-p)/itemsize/rows)
        remainder = (s-p)-cols*rows*itemsize
        if dofix
            h2(3) = cols;
            fseek(f,hp,'bof');
            fwrite(f,h2,'int32');
            break
            
            % NOT WORKING
            % cannot resize file, so append spurious
            hs = 5*4;
            contentsize = max(1,remainder);
            tmp = zeros(contentsize,1);
            
            h3 = [0,1,contentsize,0,5]; % dummy header 1 by contentsize
            fwrite(f,h3,'int32');
            fwrite(f,'dummy','uint8');  % name
            fwrite(f,tmp,'double');     % data
            
        else            
            newheader = h2
        end
        break
    else
        skip = rows*cols*itemsize;
        fseek(f,skip,'cof');
    end
end
fclose(f)
end