CPP / C++ - Embed Resources Into Executables

$ xxd -i protocols.txt 

unsigned char protocols_txt[] = {
  0x23, 0x20, 0x2f, 0x65, 0x74, 0x63, 0x2f, 0x70, 0x72, 0x6f, 0x74, 0x6f,
  0x63, 0x6f, 0x6c, 0x73, 0x3a, 0x0a, 0x23, 0x20, 0x24, 0x49, 0x64, 0x3a,
  0x20, 0x70, 0x72, 0x6f, 0x74, 0x6f, 0x63, 0x6f, 0x6c, 0x73, 0x2c, 0x76,
 ... ...  ... ...  ... ...  ... ...  ... ...  ... ...   
  0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x5b, 0x49, 0x41,
  0x4e, 0x41, 0x5d, 0x0a
};
unsigned int protocols_txt_len = 6568;

$ xxd -i protocols.txt > program_asset.h

# Compile header containing resource to object-code 
$ g++ -c program_asset.h -o program_asset.o

# Link and generate the application with embedded resource 
$ g++ main.o file1.o file2.o program_asset.o -o program.exe 

cmake_minimum_required(VERSION 3.0)
project(duktape-cc-trial)

set(CMAKE_CXX_STANDARD 17)
set(CMAKE_VERBOSE_MAKEFILE ON)

#--------------------------------#

macro(Download_Single_Headerlib FILE URL)
  file(DOWNLOAD ${URL} ${CMAKE_BINARY_DIR}/include/${FILE})
  IF(NOT Download_Single_Headerlib_flag)
    include_directories(${CMAKE_BINARY_DIR}/include)
    set(Download_Single_Headerlib_flag TRUE)
  ENDIF()
endmacro()


Download_Single_Headerlib(
  incbin.h
  "https://raw.githubusercontent.com/graphitemaster/incbin/8cefe46d5380bf5ae4b4d87832d811f6692aae44/incbin.h"
  )
include_directories(${CMAKE_CURRENT_LIST_DIR})

#--------- Main Target -------------#

add_executable(main app.cpp)

#include <iostream>
#include <string>

#define INCBIN_STYLE INCBIN_STYLE_SNAKE
#define INCBIN_PREFIX g_
#include <incbin.h>

/* Usage: INCBIN(<<LABLE>>, <<FILE>>)
 *
 * Symbols defined by INCBIN 
 * ------------------------------------------ 
 *  const unsigned char        g_asset_data[]  // g_<<LABLE>>_data 
 *  const unsigned char* const g_asset_end;    // g_<<LABEL>>_end 
 *  const unsinged int         g_asset_size;   // g_<<LABEL>>_size 
 */
INCBIN(asset, "data.txt");

#define MEMORY_STREAM(label) \
  memstream( (char*) ((g_ ## label ## _data)),              \
             (char*) ((g_ ##label ## _data) + (g_ ## label ##_size)))

/// Credits: https://stackoverflow.com/a/13059195
/// https://stackoverflow.com/questions/13059091/
struct membuf: std::streambuf {
  membuf(char const* base, size_t size) {
    char* p(const_cast<char*>(base));
    this->setg(p, p, p + size);
  }
  virtual ~membuf() = default;
};

/// Credits: https://stackoverflow.com/a/13059195
/// https://stackoverflow.com/questions/13059091/
struct memstream: virtual membuf, std::istream {

  memstream(char const* base, char* const end)
    : membuf(base, reinterpret_cast<uintptr_t>(end) - reinterpret_cast<uintptr_t>(base) )
    , std::istream(static_cast<std::streambuf*>(this)) { }

  memstream(char const* base, size_t size)
    : membuf(base, size)
    , std::istream(static_cast<std::streambuf*>(this)) { }
};

// Read all lines from some input stream
// and print on stdout.
void print_lines(std::istream& is)
{
  std::string line;
  int  n = 0;
  while(std::getline(is, line) && n < 25)
    std::cout << " line[" << n++ << "] = " << line << std::endl;
}

int main()
{

  std::puts("\n [EXPERIMENT 1] =>> Read directly from symbols ---");  
  std::string text = std::string(g_asset_data, g_asset_data + g_asset_size);
  std::cout << " Content of the asset file is " << std::endl;
  std::cout << " => " << text << std::endl;

  std::puts("\n [EXPERIMENT 2] =>> Read from memory stream -------");
  auto is = MEMORY_STREAM(asset);
  print_lines(is);

  return 0;
}

"At vero eos et accusamus et iusto odio dignissimos ducimus qui
blanditiis praesentium voluptatum deleniti atque corrupti quos dolores
et quas molestias excepturi sint occaecati cupiditate non provident,
similique sunt in culpa qui officia deserunt mollitia animi, id est
laborum et dolorum fuga. Et harum quidem rerum facilis est et expedita
distinctio. Nam libero tempore, cum soluta nobis est eligendi optio
cumque nihil impedit quo minus id quod maxime placeat facere possimus,
omnis voluptas assumenda est, omnis dolor repellendus. Temporibus
autem quibusdam et aut officiis debitis aut rerum necessitatibus saepe
eveniet ut et voluptates repudiandae sint et molestiae non
recusandae. Itaque earum rerum hic tenetur a sapiente delectus, ut aut
reiciendis voluptatibus maiores alias consequatur aut perferendis
doloribus asperiores repellat."

$ cmake -H. -B_build -G Ninja -DCMAKE_BUILD_TYPE=Debug
$ cmake --build _build --target 

 $ cp _build/main /tmp/main.bin  && cd /tmp 

 $ ./main.bin 

 [EXPERIMENT 1] =>> Read directly from symbols ---
 Content of the asset file is 
 => "At vero eos et accusamus et iusto odio dignissimos ducimus qui
blanditiis praesentium voluptatum deleniti atque corrupti quos dolores
... ...    ... ...    ... ...    ... ...    ... ...    ... ... 
... ...    ... ...    ... ...    ... ...    ... ...    ... ... 
reiciendis voluptatibus maiores alias consequatur aut perferendis
doloribus asperiores repellat."



 [EXPERIMENT 2] =>> Read from memory stream -------
 line[0] = "At vero eos et accusamus et iusto odio dignissimos ducimus qui
 line[1] = blanditiis praesentium voluptatum deleniti atque corrupti quos dolores
 ... ... ...     ... ... ...     ... ... ...     ... ... ...     ... ... ... 
 ... ... ...     ... ... ...     ... ... ...     ... ... ...     ... ... ... 
 line[12] = doloribus asperiores repellat."
 line[13] =    

 $ file main.bin
 main.bin: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), dynamically linked, interpreter 
 /lib64/ld-linux-x86-64.so.2, BuildID[sha1]=368cd9a3d42f21e3ce76d43bb927a7fdc3c41e38, 
 for GNU/Linux 3.2.0, with debug_info, not stripped

$ strings main.bin | grep accusamus
"At vero eos et accusamus et iusto odio dignissimos ducimus qui

$ strings main.bin | grep libero
distinctio. Nam libero tempore, cum soluta nobis est eligendi optio

cmake_minimum_required(VERSION 3.9)
project(Simple_Cmake_Project)

#========== Global Configurations =============#
#----------------------------------------------#

set(CMAKE_CXX_STANDARD 17)     
set(CMAKE_VERBOSE_MAKEFILE ON)
set(CMAKE_CXX_EXTENSIONS OFF)

if(UNIX)
  # Add file textension *.bin to all executables on Unix (Linux, OSX, BSD ...)
  set(CMAKE_EXECUTABLE_SUFFIX ".bin")
endif()

# ------------ Download CmakeRC Resource compiler ----------------#

file(DOWNLOAD "https://raw.githubusercontent.com/vector-of-bool/cmrc/master/CMakeRC.cmake"
                 "${CMAKE_BINARY_DIR}/CMakeRC.cmake")
include("${CMAKE_BINARY_DIR}/CMakeRC.cmake")

#========== Targets Configurations ============#

cmrc_add_resource_library(
    app1-resources

    ALIAS app1::rc
    NAMESPACE app1

    resources/protocols.txt
    resources/hosts.txt
    resources/terminal.jpeg
    )

add_executable(application1 application1.cpp)
target_link_libraries(application1 app1::rc)

#include <iostream>
#include <fstream>
#include <cstdio>
#include <cassert>
#include <map>

#include <cmrc/cmrc.hpp>

CMRC_DECLARE(app1);

#define SHOW_EXPR(expr) \
   std::cout << " =>> EXPR( " << #expr << " ) = " << (expr) << std::endl


/// Credits: https://stackoverflow.com/a/13059195
/// https://stackoverflow.com/questions/13059091/
struct membuf: std::streambuf {
    membuf(char const* base, size_t size) {
        char* p(const_cast<char*>(base));
        this->setg(p, p, p + size);
    }
    virtual ~membuf() = default;
};

/// Credits: https://stackoverflow.com/a/13059195
/// https://stackoverflow.com/questions/13059091/
struct memstream: virtual membuf, std::istream {

    memstream(char const* base, char* const end)
        : membuf(base, reinterpret_cast<uintptr_t>(end) - reinterpret_cast<uintptr_t>(base) )
        , std::istream(static_cast<std::streambuf*>(this)) { }

    memstream(char const* base, size_t size)
        : membuf(base, size)
        , std::istream(static_cast<std::streambuf*>(this)) { }
};


int main(int argc, const char** argv)
{
    auto fs = cmrc::app1::get_filesystem();

    std::cout << std::boolalpha;

    std::puts("\n ========= Experiment 1 ==>> Check resources ==========");

    SHOW_EXPR( fs.is_file("resources/protocols.txt") );
    SHOW_EXPR( fs.is_file("resources/hosts.txt") );
    SHOW_EXPR( fs.is_file("/resources/hosts.txt") );
    SHOW_EXPR( fs.is_file("resources/protoc.txt") );

    std::puts("\n ========= Experiment 2 ==>> Read resource ==========");
    {
        auto fd1 = fs.open("resources/hosts.txt");

        // Read whole file content to string
        auto st1 = std::string(fd1.begin(), fd1.end());

        std::cout << "\n Content of resources/hosts = \n" << st1 << std::endl;
    }

    std::puts("\n ========= Experiment 3 ===>> Read resource as stream ===");
    {

        auto fd2 = fs.open("resources/protocols.txt");

        auto is = memstream ( const_cast<char*>(fd2.begin()),
                              const_cast<char*>(fd2.end()) );

        std::string line;
        int  n = 0;
        while(std::getline(is, line) && n < 25)
            std::cout << " line[" << n++ << "] = " << line << std::endl;

    }

    std::puts("\n ========= Experiment 4 ===>> Extract resource to file ===");
    {
        auto fd = fs.open("resources/terminal.jpeg");

        auto is = memstream ( const_cast<char*>(fd.begin()),
                              const_cast<char*>(fd.end()) );


        auto ofs = std::ofstream("/tmp/picture.jpeg");
        // Redirect is to ofs
        ofs << is.rdbuf();
        // Force writing
        ofs.flush();
    }

    return 0;
}

$ ./application1.bin 

========= Experiment 1 ==>> Check resources ==========
 =>> EXPR( fs.is_file("resources/protocols.txt") ) = true
 =>> EXPR( fs.is_file("resources/hosts.txt") ) = true
 =>> EXPR( fs.is_file("/resources/hosts.txt") ) = true
 =>> EXPR( fs.is_file("resources/protoc.txt") ) = false

 ========= Experiment 2 ==>> Read resource ==========

 Content of resources/hosts = 
127.0.0.1   localhost localhost.localdomain localhost4 localhost4.localdomain4
::1         localhost localhost.localdomain localhost6 localhost6.localdomain6
127.0.0.1 hostname


 ========= Experiment 3 ===>> Read resource as stream ===
 line[0] = # /etc/protocols:
 line[1] = # $Id: protocols,v 1.12 2016/07/08 12:27 ovasik Exp $
 line[2] = #
 line[3] = # Internet (IP) protocols
 line[4] = #
 line[5] = #    from: @(#)protocols     5.1 (Berkeley) 4/17/89
 line[6] = #
 line[7] = # Updated for NetBSD based on RFC 1340, Assigned Numbers (July 1992).
 line[8] = # Last IANA update included dated 2011-05-03
 line[9] = #
 line[10] = # See also http://www.iana.org/assignments/protocol-numbers
 line[11] = 
 line[12] = ip  0       IP              # internet protocol, pseudo protocol number
 line[13] = hopopt      0       HOPOPT          # hop-by-hop options for ipv6
 line[14] = icmp        1       ICMP            # internet control message protocol
 line[15] = igmp        2       IGMP            # internet group management protocol
 line[16] = ggp 3       GGP             # gateway-gateway protocol
 line[17] = ipv4        4       IPv4            # IPv4 encapsulation
 line[18] = st  5       ST              # ST datagram mode
 line[19] = tcp 6       TCP             # transmission control protocol
 line[20] = cbt 7       CBT             # CBT, Tony Ballardie <A.Ballardie@cs.ucl.ac.uk>
 line[21] = egp 8       EGP             # exterior gateway protocol
 line[22] = igp 9       IGP             # any private interior gateway (Cisco: for IGRP)
 line[23] = bbn-rcc     10      BBN-RCC-MON             # BBN RCC Monitoring
 line[24] = nvp 11      NVP-II          # Network Voice Protocol

 ========= Experiment 4 ===>> Extract resource to file ===

include <stdint.h>
#include <stdlib.h>

static char encoding_table[] = {'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H',
                                'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P',
                                'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X',
                                'Y', 'Z', 'a', 'b', 'c', 'd', 'e', 'f',
                                'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n',
                                'o', 'p', 'q', 'r', 's', 't', 'u', 'v',
                                'w', 'x', 'y', 'z', '0', '1', '2', '3',
                                '4', '5', '6', '7', '8', '9', '+', '/'};
static char *decoding_table = NULL;
static int mod_table[] = {0, 2, 1};


char *base64_encode(const unsigned char *data,
                    size_t input_length,
                    size_t *output_length) {

    *output_length = 4 * ((input_length + 2) / 3);

    char *encoded_data = malloc(*output_length);
    if (encoded_data == NULL) return NULL;

    for (int i = 0, j = 0; i < input_length;) {

        uint32_t octet_a = i < input_length ? (unsigned char)data[i++] : 0;
        uint32_t octet_b = i < input_length ? (unsigned char)data[i++] : 0;
        uint32_t octet_c = i < input_length ? (unsigned char)data[i++] : 0;

        uint32_t triple = (octet_a << 0x10) + (octet_b << 0x08) + octet_c;

        encoded_data[j++] = encoding_table[(triple >> 3 * 6) & 0x3F];
        encoded_data[j++] = encoding_table[(triple >> 2 * 6) & 0x3F];
        encoded_data[j++] = encoding_table[(triple >> 1 * 6) & 0x3F];
        encoded_data[j++] = encoding_table[(triple >> 0 * 6) & 0x3F];
    }

    for (int i = 0; i < mod_table[input_length % 3]; i++)
        encoded_data[*output_length - 1 - i] = '=';

    return encoded_data;
}

unsigned char *base64_decode(const char *data,
                             size_t input_length,
                             size_t *output_length) {
    if (decoding_table == NULL) build_decoding_table();

    if (input_length % 4 != 0) return NULL;

    *output_length = input_length / 4 * 3;
    if (data[input_length - 1] == '=') (*output_length)--;
    if (data[input_length - 2] == '=') (*output_length)--;

    unsigned char *decoded_data = malloc(*output_length);
    if (decoded_data == NULL) return NULL;

    for (int i = 0, j = 0; i < input_length;) {

        uint32_t sextet_a = data[i] == '=' ? 0 & i++ : decoding_table[data[i++]];
        uint32_t sextet_b = data[i] == '=' ? 0 & i++ : decoding_table[data[i++]];
        uint32_t sextet_c = data[i] == '=' ? 0 & i++ : decoding_table[data[i++]];
        uint32_t sextet_d = data[i] == '=' ? 0 & i++ : decoding_table[data[i++]];

        uint32_t triple = (sextet_a << 3 * 6)
        + (sextet_b << 2 * 6)
        + (sextet_c << 1 * 6)
        + (sextet_d << 0 * 6);

        if (j < *output_length) decoded_data[j++] = (triple >> 2 * 8) & 0xFF;
        if (j < *output_length) decoded_data[j++] = (triple >> 1 * 8) & 0xFF;
        if (j < *output_length) decoded_data[j++] = (triple >> 0 * 8) & 0xFF;
    }

    return decoded_data;
}


void build_decoding_table() {
    decoding_table = malloc(256);
    for (int i = 0; i < 64; i++)
        decoding_table[(unsigned char) encoding_table[i]] = i;
}


void base64_cleanup() {
    free(decoding_table);
}