open a hex file

I use the following code to open a hex file (please look at the attachment).

fid = fopen('FileName');

A = fread(fid);

My problem is instead of getting A as a cell containg n*1 (n is the number of rows in the hex file) I get one row of numbers. I would appreciate it if you help me get a result like below:

00 00 00 00 49 40 40 0D

03 00 30 43 C6 02 00 00

A3 6B 74 23 90 47 E4 40

and so on

[Azzi Abdelmalek]

Can you post the result you've got? maybe with simple use of reshape function you can get the expected result

Answer 1

[Jan]

There is not format you can call "hex file". You can interpret a file as stream of bytes and display them by hex numbers. But from this point of view, any file is a hex file.

Please try this:

fid = fopen('FileName');
A   = fread(fid, Inf, 'uint8');
fclose(fid);
Fmt = repmat('%02X ', 1, 16);  % Create format string
Fmt(end) = '*';                % Trailing star
S   = sprintf(Fmt, A);         % One long string
C   = regexp(S, '*', 'split'); % Split at stars

Perhaps a string with line breaks is sufficient:

Fmt = repmat('%02X ', 1, 16);  % Create format string
Fmt(end:end+1) = '\n';
S   = sprintf(Fmt, A);

[Ronaldo]

When the file is large, I get the following error for line 2:

OUT of MEMORY

[Jan]

@Ronaldo: Please specify "large". Some people in the forum use this for 1000 elements, some for 1e15 elements.

When importing the file exhausts too much memory, install more memory, use a 64 bit version of Matlab and OS, free arrays, which are not used anymore. You can import the data by fread(fid, Inf, '*uint8') also, which occupies just an 8.th of the memory. But for SPRINTF a modern Matlab version is required then, because older ones did not accept UINT8 as input.

[Ronaldo]

The file that I want to open is 5 GB. I am using a 64 bit version of MATLAB and OS. Available physical memory of my computer is 31.2 GB. I was wondering whether there is anyway that I can prevent OUT of MEMORY problem if I want to open the 5 GB file.

Answer 2

[Azzi Abdelmalek]

fid = fopen('file.txt');
A = textscan(fid,'%s  %s  %s  %s  %s  %s  %s  %s')
fclose(fid)
A=[A{:}]
arrayfun(@(x) strjoin(A(1,:)),(1:3)','un',0)

[Walter Roberson]

Use '%x%x%x%x%x' instead of %s if the numeric form is desired.

[Ronaldo]

The extension of the original file is not txt.

[Ronaldo]

If I use the following code for the problem, I get the result that I want

fid = fopen('FIleName');

a = fread(fid);

for i=1:size(a,1)

sprintf('%02X %02X %02X %02X %02X %02X %02X %02X %02X %02X %02X %02X %02X %02X %02X %02X',a(8*i-7:8*i,1))

end

BUT if the file size is large then this code is not working. This is the reason why I want "a" to be (n*1 cell which each cell contains one row of the image attached to the question) instead of a complete row or column. of all the elements in the hex file.

[Azzi Abdelmalek]

Post the first samples you've got with

A = fread(fid);

[Azzi Abdelmalek]

If the data you've got are like:

A={'00' ;'00' ;'00';'00'; '49'; '40' ;'40' ;'0D'; '03';  '00' ;'30' ;'43'; 'C6'; '02'; '00' ;'00'}

You can make some transformations

out=reshape(A,8,[])'
result=arrayfun(@(x) strjoin(out(x,:)),(1:size(out,1))','un',0)

[Ronaldo]

It is a column of double numbers. If I use dec2hex for each element of the column, I get the equivalent value in the original hex file. As you can see in the attachment the hex file contains different rows, I like "a" also contains several rows to avoid memory leak!

[Azzi Abdelmalek]

Decimal numbers? please edit your question and make it as clear as possible

[Jan]

@Ronaldo: A memory leak? I assume, you mean something completely different.