Question

I have a binary file packing lots of files (something like a .tar), where I can found both binary and text files.

When processing in memory strings, carriage lines are usually ‘\n’, but if I read the text part from this packed file, I get “\r\n”. Therefore processing this text gives me errors.

Here is the code for reading the text from a binary file:

FILE* _fileDescriptor;                        // it's always open to improve performance
fopen_s(&_fileDescriptor, _filePath.string().c_str(), "rb"); 

char* data = new char[size + 1];              // size is a known and correct value
fseek(_fileDescriptor, begin, SEEK_SET);      // begin is another known value, where the file starts inside the packed one
fread(data, sizeof(char), size, _fileDescriptor);
data[it->second.size] = '\0';

This gives me the right text into data, but the following code gives me error when reading an empty line:

istringstream ss(data);      // create a stringstream to process it in another function
delete[] data;               // free the data buffer

// start processing the file
string line;
getline(infile, line);       // read an empty line

if(line.size() > 0) {
    /*
     enters here, because the "empty" line was "\r\n", and now the value of line is '\r', therefore line.size() == 1
    */
    ...

So, any advice to avoid the ‘\r’?

I edited it on Notepad++. Changing its configuration to use ‘\n’ instead of ‘\r\n’ as line carriage works, but I don’t want to depend on this because other people can miss that, and it would be very hard to spot the problem if that happens.

Answer 1

Probably easiest to trim the ‘\r’ characters out of your string and then discard blank lines. See this answer for approaches to trimming a std::string (I’m assuming that’s what ‘line’ is):

What's the best way to trim std::string?