dlib C++ Library - file_to_code_ex.cpp

    /*
        This is an example illustrating the use of the compress_stream and
        base64 components from the dlib C++ Library.

        It reads in a file from the disk and compresses it in an in memory buffer and
        then converts that buffer into base64 text.  The final step is to output to
        the screen some C++ code that contains this base64 encoded text and can decompress
        it back into its original form.
    */

    #include <iostream>
    #include <fstream>
    #include <sstream>
    #include <string>
    #include <cstdlib>
    #include "dlib/compress_stream.h"
    #include "dlib/base64.h"

    using namespace std;
    using namespace dlib;

    int main(int argc, char** argv)
    {
        if (argc != 2)
        {
            cout << "You must give a file name as the argument to this program.\n" << endl;
            cout << "This program reads in a file from the disk and compresses\n"
                 << "it in an in memory buffer and then converts that buffer \n"
                 << "into base64 text.  The final step is to output to the screen\n"
                 << "some C++ code that contains this base64 encoded text and can\n"
                 << "decompress it back into its original form.\n" << endl;

            return EXIT_FAILURE;
        }

        // open the file the user specified on the command line
        ifstream fin(argv[1], ios::binary);
        if (!fin) {
            cout << "can't open file " << argv[1] << endl;
            return EXIT_FAILURE;
        }

        ostringstream sout;
        istringstream sin;

        // this is the object we will use to do the base64 encoding
        base64::kernel_1a base64_coder;
        // this is the object we will use to do the data compression
        compress_stream::kernel_1ea compressor;

        // compress the contents of the file and store the results in the string stream sout
        compressor.compress(fin,sout);
        sin.str(sout.str());
        sout.clear();
        sout.str("");

        // now base64 encode the compressed data
        base64_coder.encode(sin,sout);

        sin.clear();
        sin.str(sout.str());
        sout.str("");

        // the following is a little funny looking but all it does is output some C++ code
        // that contains the compressed/base64 data and the C++ code that can decode it back
        // into its original form.
        sout << "#include <sstream>\n";
        sout << "#include <dlib/compress_stream.h>\n";
        sout << "#include <dlib/base64.h>\n";
        sout << "\n";
        sout << "// This function returns the contents of the file '" << argv[1] << "'\n";
        sout << "const std::string get_decoded_string()\n";
        sout << "{\n";
        sout << "    dlib::base64::kernel_1a base64_coder;\n";
        sout << "    dlib::compress_stream::kernel_1ea compressor;\n";
        sout << "    std::ostringstream sout;\n";
        sout << "    std::istringstream sin;\n\n";

        sout << "    // The base64 encoded data from the file '" << argv[1] << "' we want to decode and return.\n";
        string temp;
        getline(sin,temp);
        while (sin && temp.size() > 0)
        {
            sout << "    sout << \"" << temp << "\";\n";
            getline(sin,temp);
        }

        sout << "\n";
        sout << "    // Put the data into the istream sin\n";
        sout << "    sin.str(sout.str());\n";
        sout << "    sout.str(\"\");\n\n";
        sout << "    // Decode the base64 text into its compressed binary form\n";
        sout << "    base64_coder.decode(sin,sout);\n";
        sout << "    sin.clear();\n";
        sout << "    sin.str(sout.str());\n";
        sout << "    sout.str(\"\");\n\n";
        sout << "    // Decompress the data into its original form\n";
        sout << "    compressor.decompress(sin,sout);\n\n";
        sout << "    // Return the decoded and decompressed data\n";
        sout << "    return sout.str();\n";
        sout << "}\n";

        // finally output our encoded data and its C++ code to the screen
        cout << sout.str() << endl;
    }