GateWay 3.0 Launcher Creator

#define _CRT_SECURE_NO_WARNINGS true

#include <cstdio>
#include <memory>

void main(int argc, char *argv[]) {
    if (argc < 2)
        return;

    //Load ROP
    FILE *IFile = fopen(argv[1], "rb+");
    fseek(IFile, 0, SEEK_END);
    int bSize = ftell(IFile) > 0x4000 ? 0x4000 : ftell(IFile); //Limit 0x4000 bytes size
    fseek(IFile, 0, SEEK_SET);
    int *buffer = (int*)malloc(0x4000);
    fread(buffer, 1, bSize, IFile);
    fclose(IFile);

    //Encrypt ROP
    for (int state = 0xD5828281, i = 0; i < 0x4000 / 4; i++, state += 0xD5828281)
        buffer[i] -= state;

    //Save ROP
    IFile = fopen("Launcher.dat", "wb+");
    fseek(IFile, 0x00012000, SEEK_SET); //4.X Users
    fwrite(buffer, 1, 0x4000, IFile);
    fseek(IFile, 0x0001A000, SEEK_SET); //5.X+ Users
    fwrite(buffer, 1, 0x4000, IFile);
    fclose(IFile);

    free(buffer);
}