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#include <bits/stdc++.h>
#include <unistd.h>
#include <dirent.h>
#include <sys/stat.h>
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <unistd.h>
extern int errno;

using namespace std;
typedef long long ll;
#define all(x) (x).begin(), (x).end()


char* filenames[10];
int filenames_sz = 0;
int shift = 4uLL;

void fetch_filenames(const char *prog_name){
    size_t v1; // rax
    size_t sz; // [rsp+10h] [rbp-30h]
    DIR *dir; // [rsp+18h] [rbp-28h]
    size_t filename_sz; // [rsp+20h] [rbp-20h]
    struct dirent *entry; // [rsp+30h] [rbp-10h]
    char *filename; // [rsp+38h] [rbp-8h]

    dir = opendir(".");
    if ( !dir )
    {
        perror("Error opening directory");
        exit(-1);
    }

    sz = 0LL;
    while ( 1 )
    {
        entry = readdir(dir);
        if ( !entry || sz > 0xFE )
            break;
        if ( strcmp(entry->d_name, ".")
             && strcmp(entry->d_name, "..")
             && strcmp(entry->d_name, prog_name + 2)
             && !strncmp(entry->d_name, "ch4ll3ng_", 9uLL) )
        {
            filename_sz = strlen(entry->d_name) + 1;
            filename = (char *)malloc(filename_sz);
            strncpy(filename, entry->d_name, filename_sz);
            v1 = sz++;
            filenames[v1] = filename;
        }
    }
    filenames_sz = sz;
    closedir(dir);
}


// Modified function to get seed of a valid .png file
int64_t  generate_rng_seed()
{
    int fd; // [rsp+Ch] [rbp-14h]
    int64_t seed[2]; // [rsp+10h] [rbp-10h] BYREF
    int idx = 0;
    string seedProvider = "seedprovider.png";
    cout << "seed file: " << seedProvider<< endl;
    fd = open(seedProvider.c_str(), 0);
    if ( fd == -1 )
    {
        perror("Error opening file");
        exit(-1);
    }
    read(fd, seed, 8uLL);
	// seed[0] must always be 727905341920923785
    cout << "SEED: " << seed[0] << endl;
    return seed[0];
}
size_t  get_file_sz(const char *filename)
{
    struct stat st;
    stat(filename, &st);
    return st.st_size;
}
void  read_file(const char *filename, char *buf, size_t sz)
{
    int fd; // [rsp+2Ch] [rbp-4h]
    fd = open( filename, 2);
    string x(filename);
    lseek(fd, shift, 0);
    read(fd, buf, sz);
    close(fd);
}
char * append_ext(const char *filename)
{
    size_t v1; // rax
    size_t file_sz; // [rsp+10h] [rbp-10h]
    char *new_filename; // [rsp+18h] [rbp-8h]

    v1 = strlen(filename);
    file_sz = v1 + 1;
    new_filename = (char *)malloc(v1 + 6);
    strncpy(new_filename, filename, file_sz);
    strcat(new_filename, ".png");
    return new_filename;
}
void  enc_data(char *data, size_t sz)
{
    size_t i; // [rsp+18h] [rbp-8h]

    for ( i = 0LL; i < sz; ++i )
        data[i] ^= rand() % 256;
}
void  create_enc_file(const char *filename, char *data, size_t sz, unsigned int id)
{
    unsigned int ida; // [rsp+4h] [rbp-2Ch] BYREF
    size_t sza; // [rsp+8h] [rbp-28h]
    char *dataa; // [rsp+10h] [rbp-20h]
    const char *filenamea; // [rsp+18h] [rbp-18h]
    int fd; // [rsp+2Ch] [rbp-4h]

    filenamea = filename;
    dataa = data;
    sza = sz;
    ida = id;

    fd = open(filename, O_RDWR | O_CREAT, 384LL);
    if ( fd == -1 )
    {
        perror("open");
        exit(-1);
    }
	// Commenting out the next line, to only use the data.
	//write(fd, &ida, 4uLL);
    write(fd, dataa, sza);
    close(fd);
}
void  enc_file(const char *filename, unsigned int id)
{
    size_t file_sz; // [rsp+18h] [rbp-18h]
    char *buf; // [rsp+20h] [rbp-10h]
    char *enc_filename; // [rsp+28h] [rbp-8h]
    file_sz = get_file_sz(filename) - shift;
    buf = (char *)malloc(file_sz);
    read_file(filename, buf, file_sz);

	
	// adding an extra out_ prefix.
    std::string tmp(filename);
    string out = "out_" + tmp;
    filename = out.c_str();

    enc_filename = append_ext(filename);
    enc_data(buf, file_sz);
    create_enc_file(enc_filename, buf, file_sz, id);
    free(enc_filename);
    free(buf);
}

int main(int argc, const char **argv) {
    fetch_filenames(*argv);
    unsigned int rng_seed; // eax
    rng_seed = generate_rng_seed();
    srand(rng_seed);
    for (int i = 0LL; i < filenames_sz; ++i )
        enc_file(filenames[i], i);
}