keyxorer

/*
    keyxorer by xerpi
    compile with:
        gcc -O3 keyxorer.c -o keyxorer
    usage:
        keyxorer <input file> <key file>

    the output will be <input file>.out
    *"big" input files and "small" keys*
*/

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

void print_usage();

int main(int argc, char *argv[])
{
    int ret_val = EXIT_SUCCESS;

    if (argc < 3) {
        print_usage();
        ret_val = EXIT_FAILURE;
        goto exit_fail_1;
    }

    FILE *fd_in, *fd_key, *fd_out;
    if (!(fd_in = fopen(argv[1], "rb"))) {
        printf("Error opening input file\n");
        ret_val = EXIT_FAILURE;
        goto exit_fail_1;
    }
    if (!(fd_key = fopen(argv[2], "rb"))) {
        printf("Error opening key file\n");
        ret_val = EXIT_FAILURE;
        goto exit_fail_2;
    }

    fseek(fd_in, 0, SEEK_END);
    long int in_size = ftell(fd_in);
    fseek(fd_in, 0, SEEK_SET);

    fseek(fd_key, 0, SEEK_END);
    long int key_size = ftell(fd_key);
    fseek(fd_key, 0, SEEK_SET);
    unsigned char *key_buf  = malloc(key_size);
    unsigned char *data_buf = malloc(key_size);
    if (key_size != fread(key_buf, 1, key_size, fd_key)) {
        printf("Cannot read key file\n");
        ret_val = EXIT_FAILURE;
        goto exit_fail_3;
    }

    char *out_name = malloc(strlen(argv[1]) + strlen(".out") + 1);
    sprintf(out_name, "%s.out", argv[1]);

    if (!(fd_out = fopen(out_name, "wb+"))) {
        printf("Cannot create output file\n");
        ret_val = EXIT_FAILURE;
        goto exit_fail_4;
    }

    #define BAR_LEN 50
    long int temp_read = 0;
    long int step_bytes = in_size/100;
    long int percent = 1;
    size_t bytes_read;
    while ((bytes_read = fread(data_buf, 1, key_size, fd_in))) {
        size_t i;
        for (i = 0;  i < bytes_read; i++) {
            data_buf[i] ^= key_buf[i];
        }
        fwrite(data_buf, 1, bytes_read, fd_out);

        //Progress bar
        temp_read += bytes_read;
        if (temp_read >= step_bytes) {
            percent++;
            temp_read = 0;
            printf("%3li%% [", percent);
            int j;
            int bar_size = (BAR_LEN*percent)/100;
            for (j = 0; j < BAR_LEN; j++) {
                if (j < bar_size) printf("=");
                else if (j == bar_size) printf(">");
                else printf(" ");
            }
            printf("]\r");
            fflush(stdout);
        }
    }
    fflush(fd_out);
    fclose(fd_out);
    printf("\nFinished!\n");
exit_fail_4:
    free(out_name);
exit_fail_3:
    free(data_buf);
    free(key_buf);
    fclose(fd_key);
exit_fail_2:
    fclose(fd_in);
exit_fail_1:
    return ret_val;
}

void print_usage()
{
    printf("keyxorer by xerpi\n"
           "usage: keyxorer <input file> <key file>\n"
           "the output will be <input file>.out\n");
}