Question

I have been Googling around, and cannot lock on to what I am trying to do. I get things about reading a ‘binary file’ but in these links, people mention headers and formatting, which seems contrary to what I am after.

end goal: encrypt any file in a picture (assuming the picture is big enough for the file).

starting goal: read in any file of any extension into a c++ vector (or whatever — if something is superior, I am up for suggestions) and then rewrite that same file onto the hard drive under a different name. After, I want to check to see if the file still works/is the same size/etc.

So I am trying to make sure I have the ability to suck in a file into ‘A’ and be able to write a file once it’s in ‘A’ before I splice up the contents of ‘A’ and stick it into an image.

Thank you for your references.

Answer 1

There are better (and more efficient) ways to copy a file. However to answer your specific question:

#include <fstream>
#include <vector>

int main()
{
   std::ifstream in("input_file", std::ios::binary);

   auto beg = in.tellg();
   in.seekg(0, std::ios::end);
   auto end = in.tellg();

   auto sz = end - beg;

   std::vector<char> outbuf;

   if(0 != sz)
   {
      in.seekg(0, std::ios::beg);
      outbuf.resize(sz);

      in.read(&outbuf[0], outbuf.size());

      std::ofstream out("output_file", std::ios::binary);
      out.write(&outbuf[0], outbuf.size());
   }
}