C++ Binary in a variable

Question

I want to read binary with Python and then store the binary in a header file for a C++ program. How can I store this binary data for later use like writing it to an .exe file to execute it? What encoding should I use?

Also is for example \x00 ASCII or HEX? Can I encode the binary in ASCII then store it in a header file for later use in C++ and then convert it to binary on the go to write the variable content to a file in binary format? How can I achieve this.

A little more clarification. C++ Header file will have a variable storing binary data, but I don't know how to achieve that, since I don't think it's as simple as pouring the binary data to a char pointer like this

char *binary = "?>!#{PL{"; // Some unreadable by text editors binary data go here

I think it should be more like

char *binary = "\x00\x01\x04"; // When I encoded it in ASCII it was in this format, but I remember that HEX format was similar too maybe even the same?

Or even storing it in an array in this format

char binaryp[] = { 0x546, 0x423 etc...};

But for that I need a Separator in my Python code.

Python code:

with open("../testing.exe", "rb") as f:

with open("asd.txt", "wb") as b:
    while True:
        c = f.read(1)
        if not c:
            break
        b.write("{}".format(c).encode("ascii")) # Or HEX

In general I just want to store binary in a C++ variable and it doesn't matter if it's readable or not I just want to be able to write it to a binary file in the end, without doing any kind of reading on C++ side. Think it as if you already have some binary data on a variable in C++ and you just write it down to an exe file and it works. The issue is I don't know what's the easiest way to do it and the best way. The Performance isn't as important, but if you have a better solution I'm always happy to listen!

Those are HEX values, do I have to convert them to binary before writing to an .exe file or can I directly write them? I assume not. Also why bother with separating them in an array, can't I just write the HEX values onto a single string like char hexvalue[] = "442342ado1FKO11a" without 0x part, since that part is only to notify the computer that that value is a HEX value? — , Feb 10 '20 at 21:06
For example I don't really care what encoding I'm using as long as in the end I'm able to convert everything onto raw binary data and when I write that RAW BINARY data onto a file it should work as if I just copied it. — , Feb 10 '20 at 21:08
FYI, if you *store* values in a C header file, you'll need to recompile or write code that can parse a C header file. Much simpler to put the data into file using a data language like JSON, HTML, XML, or INI. — Thomas Matthews, Feb 10 '20 at 21:46

score 0 · Answer 1 · answered Feb 10 '20 at 22:33

The Answer is python bytes to C array (like xxd program"

from binascii import hexlify

with open("../testing.exe", "rb") as f:

with open("header.hpp", "w") as b:
    arr = []
    while True:
        c = f.read(1)
        if not c:
            b.write("unsigned char buff[] = {{{}}};".format(b", ".join(arr)))
            break
        arr.append(b"0x" + hexlify(c))

This will produce the wished header file and after that you can just write the buffer onto a file with binary mode on aka "wb" on C/C++. Note that this code will wrap the array in b' ' don't forget to remove that before any use. This code will produce an array of HEX code, each equaling to a byte of the binary desired.

score -1 · Answer 2 · answered Feb 10 '20 at 20:47

-1

Encode the binary using Base 64 or some other text compatible encoding

base64 decode snippet in c++

answered Feb 10 '20 at 20:47

Lou Franco

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Might you explain this solution a little furthermore? For example what's the difference of encoding it in Base 64 and ASCII or HEX? Which one is easier to implement? – Feb 10 '20 at 21:07
It’s the standard way to do this that would work in any language. There are typically libraries to decode/encode, and even implementing it yourself is trivial. Another choose is UUEncoding. Your use case is exactly why they were designed and what they are used for : embedding binary formats in text. – Lou Franco Feb 10 '20 at 23:28

C++ Binary in a variable

2 Answers2