#include <fcntl.h>
#include <inttypes.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>

int main(int argc, char *argv[]) {
    char *input = argv[1];
    char *output = argv[2];
    int input_filedesc = open(input, O_RDONLY);
    int output_filedesc =
        open(output, O_WRONLY | O_CREAT | O_TRUNC, S_IRUSR | S_IWUSR);
    int32_t mod = atoi(argv[3]);
    int read_bytes;
    uint64_t ind = 1;
    uint64_t sum = 0;
    uint8_t buf;
    while ((read_bytes = read(input_filedesc, &buf, 1)) == 1) {
        for (size_t i = 0; i < (1 << 3); ++i) {
            sum = (sum + (ind * ind) % mod) % mod;
            if ((buf & (1 << i)) >> i) {
                if (write(output_filedesc, &sum, sizeof(int32_t)) ==
                    sizeof(int32_t)) {
                }
            }
            ++ind;
        }
    }
    close(input_filedesc);
    close(output_filedesc);
}