Read text file line-by-line in deployed application

I am trying to read a large TXT file in my deployed application, but I am encountering memory limitations. Therefore, I would like to read in the TXT file line by line, but the function 'fgetl' is not supported for C/C++ code generation with MATLAB Coder.

Is there any other way to read a TXT file line by line?

Answer 1

[MathWorks Support Team]

This can be achieved using the functions "fgets" or "fgetl". The code generation support for these functions was introduced in R2019b. See the documentation for additional details:

https://www.mathworks.com/help/releases/R2019b/matlab/ref/fgets.html

https://www.mathworks.com/help/releases/R2019b/matlab/ref/fgetl.html

For C/C++ deployment of your MATLAB code in releases prior to R2019b, you will have to write your own implementation of this functionality.

One possible solution to read a TXT file line-by-line could be as follows:

function main
%#codegen
fid = fopen('myfile.txt');
lne = myfgetl(fid);
while ~isempty(lne)
    fprintf(1,'%s',lne);
    fprintf(1,'%s',sprintf('\n'));
    lne = myfgetl(fid);
end
fclose(fid);
end

function line  = myfgetl(fid)
line = '';
c = fread(fid,1,'char=>char');
while ~feof(fid) && ~strcmp(c, sprintf('\n'))
    if ~strcmp(c,sprintf('\r'))
        line = [line,c];
    end
    c = fread(fid,1,'char=>char');
end
end