Question

Simple question I know, what I want to do is be able to get the bytes of a file to use to add those bytes to an bit array, which I can then use to write to a file named bytes.exe and launch it. I know how to read the bytes of an existing file at runtime. But I don’t know how to get the bytes of a file to copy and paste into my bitarray[] at design time.

The goal is to be able to write the bites of bitarray[] to myfile.exe at runtime, and then launch said file. There are many bitarray[]'s I’ll be using, based on many different file types, so I’m looking for an easy method.

Is there some kind of decompiler that should be used? I just looked into resource scripts, but I don’t want to attach any dependencies to my main .exe.

Answer 1

If you are targeting Windows, the easiest way to do this is to embed myfile.exe as a resource, then load the resource at runtime and create a file and write the contents of the resource to your new file.

If you can’t use resources, then you’ll need to create a source file (.c or .h) that initializes a byte array with the contents of myfile.exe and include that as part of your build. Check out this answer for one possible approach:

https://stackoverflow.com/a/73653/333127

EDIT: After further review, I don’t think the source code in the link I referenced above will work for binary input files. Here’s a quick alternative I just threw together:

#include <stdio.h>
#include <stdlib.h>

#define BYTES_PER_LINE 70

int main(int argc, char* argv[])
{
    FILE* fp;
    int ch;
    int numBytes = 0;

    if (argc < 2) {
        printf("Usage: tobytes <file>\n");
        exit(1);
    }

    fp = fopen(argv[1], "rb");
    if (fp == NULL) {
        printf("Cannot open file %s\n", argv[1]);
        exit(1);
    }

    printf("char fileContents[] = {\n");
    while ((ch = fgetc(fp)) != EOF) {
        if (numBytes > 0)
            printf(",");

        ++numBytes;
        if (numBytes % BYTES_PER_LINE == 0)
            printf("\n");

        printf("0x%x", ch);
    }
    printf("\n};\n");

    fclose(fp);

    return 0;
}