/* filecrypt
 * By Feky
 * Simple XOR */

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

int main(int argc, char *argv[])
{
    FILE *src, *out;
    int x=0;
    size_t n;
    if(argc != 4){
        printf("Usage: %s [source_file] [output_file] [key]\n", argv[0]);
        return EXIT_FAILURE;
    }
    src = fopen(argv[1], "rb");
    out = fopen(argv[2], "wb");
    if(src == NULL || out == NULL){
        perror("Error");
        return EXIT_FAILURE;
    }
    n = strlen(argv[3]);
    while(!feof(src)){
        int p = fgetc(src);
        int q = argv[3][x%n];
        fputc(p ^ q, out);
        x++;
    }
    fclose(src);
    fclose(out);	
    return EXIT_SUCCESS;
}