Using binary data in C++ string

Question

I am working with binary data coming from a service provider. I am subscribing to this data through HTTP request, using C++. Every now and then, I get an HTML payload coming from this provider. The HTML payload is actually binary data, which looks like that:

! ¦ô¿Âˤ ÍÌL? Àÿ Àÿ¥ š™©@ Àÿ Àÿ or ! H·ô¿Âˤ ÍÌL? Àÿ333?¥ š™©@ Àÿff¦@

I would like to do simulation using the data I get. To do so I hard code the data in a string and launch my program that will use those strings.

std::string input = "! ¦ô¿Âˤ ÍÌL? Àÿ Àÿ¥ š™©@ Àÿ Àÿ"

The first issue I have is that I have to escape all characters like \n. But I don't know how to escape \0 for example. Also, I have this error message, which may be due to the fact that I don't escape the end of file character properly:

Error 3 fatal error C1004: unexpected end-of-file found

So the main question is: what does the end-of-file character looks like, and how can I escape it ?

Then, is there a linux command or a way to take binary data from a binary file, and escape all the special character with \ so then I just copy paste it in my C++ code.

Eventually, I would like to put all the different payloads I have got, in a binary file, so I can launch my simulation using this file. The issue is that I don't know how to separate different payloads, since just going to the next line won't do the trick, because it will be interpreted as a random character (and the payload don't have a fix size). I don't know what kind of separator to use.

Answer 1

You can write your payload in a file and read it using a std::ifstream. That would allow you to change the payload without having to recompile.

If you really want to store it as binary data, you can use an array of char, and initialize it like that :

const unsigned char raw_data[] = {
    0x21, 0x20, 0xc2, 0xa6, 0xc3, 0xb4, 0xc2, 0xbf,
    0xc3, 0x82, 0xc3, 0x8b, 0xc2, 0xa4, 0x20, 0xc3,
    0x8d, 0xc3, 0x8c, 0x4c, 0x3f, 0x20, 0x20, 0xc3,
    0x80, 0xc3, 0xbf, 0x20, 0x20, 0xc3, 0x80, 0xc3,
    0xbf, 0xc2, 0xa5, 0x20, 0xc5, 0xa1, 0xe2, 0x84,
    0xa2, 0xc2, 0xa9, 0x40, 0x20, 0x20, 0xc3, 0x80,
    0xc3, 0xbf, 0x20, 0x20, 0xc3, 0x80, 0xc3, 0xbf,
    0x60, 0x20, 0x6f, 0x72, 0x20, 0x60, 0x21, 0x20,
    0x48, 0xc2, 0xb7, 0xc3, 0xb4, 0xc2, 0xbf, 0xc3,
    0x82, 0xc3, 0x8b, 0xc2, 0xa4, 0x20, 0xc3, 0x8d,
    0xc3, 0x8c, 0x4c, 0x3f, 0x20, 0x20, 0xc3, 0x80,
    0xc3, 0xbf, 0x33, 0x33, 0x33, 0x3f, 0xc2, 0xa5,
    0x20, 0xc5, 0xa1, 0xe2, 0x84, 0xa2, 0xc2, 0xa9,
    0x40, 0x20, 0x20, 0xc3, 0x80, 0xc3, 0xbf, 0x66,
    0x66, 0xc2, 0xa6, 0x40, 0x0a,
};

std::string data(
    reinterpret_cast< const char* >(raw_data),
    reinterpret_cast< const char* >(raw_data) + sizeof(raw_data));

Oh, BTW, I converted your payload to a buffer using the following simple Python code:

#!/usr/bin/python

def convert_file(path, stream):
    data = open(path, 'rb').read()
    stream.write('const unsigned char raw_data[] = {')
    for i, char in enumerate(data):
        if i % 8 == 0:
            stream.write('\n   ')
        stream.write(' 0x%02x,' % (ord(char),))
    stream.write('\n};\n')

if __name__ == '__main__':
    import sys
    convert_file(sys.argv[1], sys.stdout)