How to Embed Base64 Resources in an EXE (C++)

An Elegant Self Installing Self Extraction

The concept here is simple. We are developing with Visual Studio Express and need to distribute a program that has resources (ico, ,jpeg, jpg, png, dll).

We do not want to build an installer since that requires a lot of financial overhead. We do not wish to create Click Once and signed code because that requires an expensive yearly certificate renewal.

Instead we may simply embed resources in the program as base64 strings, and later write these resources out to a files if we discover they are missing from the disk. We may also verify the resource integrity if so inclined.

You will need base64.cpp

If you are looking for an easy way to base64 encode files try the Base64 DataURI Creator.

This example relies on managed System::String for System::IO::File::Exists and System::Windows::Forms::MessageBox which may require the .NET framework. Also utilizes Application::StartupPath to notify user where files will be created. There are other ways to achieve the same results in these cases, however since I was using .NET this seemed elegant enough. Here is a simple C based file_exits function.

This is what my resources.h looks like:

#include "windows.h"
#include "base64.h"
#include <fstream>
#include <string>
	
using namespace System::Windows::Forms;

bool writeMissingEmbededResourcesToDisk(){

#define TOTAL_EMBEDED_RESOURCES 2

std::string resourceFile[TOTAL_EMBEDED_RESOURCES];  //array of file names
  std::string resourceData[TOTAL_EMBEDED_RESOURCES];  //array of base64 file data
  
  // Adjacent long strings will be auto concatenated by the compiler.  
  // Split long strings up to avoid the compiler limitation C2026:
  // error C2026: string too big, trailing characters truncated (about 12,000 per line OK)
  
  resourceFile[0] = "reddot1.png"; //data:image/png;base64,
  resourceData[0] = "iVBORw0KGgoAAAANSUhEUgAAAAUAAAAFCAYAAACNbyblAAAAHElEQVQI12P4//8/w38GI"
                    "AXDIBKE0DHxgljNBAAO9TXL0Y4OHwAAAABJRU5ErkJggg==";
  resourceFile[1] = "reddot2.png"; //data:image/png;base64,
  resourceData[1] = "iVBORw0KGgoAAAANSUhEUgAAAAUAAAAFCAYAAACNbyblAAAAHElEQVQI12P4//8/w38GI"
                    "AXDIBKE0DHxgljNBAAO9TXL0Y4OHwAAAABJRU5ErkJggg==";
                  // ^ NOTE: No dataURI header in data ^
                        
  // be SURE to update TOTAL_EMBEDED_RESOURCES above if you expand this list
  // or you will get an intermitent memory access error!
  
  bool okToCreate=false;// if they have pressed OK for the first resource, allow all of them.

for(int i=0; i<TOTAL_EMBEDED_RESOURCES; i++){
    if(!System::IO::File::Exists(gcnew System::String(resourceFile[i].c_str()))){
      if(!okToCreate){
        System::Windows::Forms::DialogResult result = System::Windows::Forms::MessageBox::Show("Resources are missing.  Automatically create required resources?\n\nFiles will be extracted to the directory where the program is located.\n\n" + Application::StartupPath +"\n", "Installation: Create resources or Exit?", MessageBoxButtons::OKCancel);
        if( result == System::Windows::Forms::DialogResult::OK ){
          okToCreate=true;
        }else return false;
      }
      // write the decoded data to the required file name
      std::string rsc_file_decoded = base64_decode(resourceData[i]);
      std::ofstream file(resourceFile[i].c_str(), std::ios_base::binary);
      file << rsc_file_decoded;
      file.close();

if(!System::IO::File::Exists(gcnew System::String(resourceFile[i].c_str()))){
        System::Windows::Forms::MessageBox::Show("Error writing resources!  Make sure you have permission to write files to the directory from which you ran the program, or try running the program as an administrator the first time so installation can complete.","Installation Error");
        return false;
      }
    }else{
    	// resource file already exists
    }
  }

return true;
}

That's all there is too it! Sample Usage:

An easy way to base64 encode files is Base64 DataURI Creator. Please note that this example does not embed the DataURI header in front of the base64 data. In some cases you may find ways to use resources without saving them to disk.

It is recommended that you place extracted resources in a directory so that the user may easily clean up extraneous files.

If you would like to see this concept in action try the windows version of ColorPick.

Comments