#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/time.h>
#include <time.h>

#define MAX 100*1024*1024-1

void printtd(struct timeval *t0, struct timeval *t1) {
        // printf("t0: %ld . %ld\n", t0->tv_sec, t0->tv_usec);
        // printf("t1: %ld . %ld\n", t1->tv_sec, t1->tv_usec);
        printf("td: %1.3f\n", (double)(((double)t1->tv_sec-t0->tv_sec) + ((double)t1->tv_usec-t0->tv_usec)/1000000));
}

int main() {
        char *data;
        struct timeval t0, t1;
        struct timezone tz;
        long int i;
        FILE *f;

	data = malloc(MAX+100);
	if (data == NULL) perror("malloc");

	printf("starting\n"); fflush(stdout);

        /* init */
        for (i=0; i<MAX; i++) { data[i] = 0; }

        /* gen random data */
        srandom(42);
        gettimeofday(&t0, &tz);
                for (i=0; i<MAX; i++) {
                  data[i] = (char)random(); 
                }
        gettimeofday(&t1, &tz);
        printtd(&t0, &t1);

        /* print */
        // for (i=0; i<100; i++) { printf("%d ", data[i]); }

        /* write */
        gettimeofday(&t0, &tz);
                f=fopen("data","w");
                for (i=0; i<10; i++) { fwrite(data, 1024*1024, 10, f); fsync(fileno(f)); };
                fflush(f);
                fclose(f);
        gettimeofday(&t1, &tz);
        printtd(&t0, &t1);

        /* init */
        for (i=0; i<MAX; i++) { data[i] = 0; }

        /* print */
        // for (i=0; i<100; i++) { printf("%d ", data[i]); }

        /* read */
        gettimeofday(&t0, &tz);
                f=fopen("data","r");
                for (i=0; i<10; i++) { fsync(fileno(f)); fread(data, 1024*1024, 10, f); };
                fclose(f);
        gettimeofday(&t1, &tz);
        printtd(&t0, &t1);

        /* print */
        // for (i=0; i<100; i++) { printf("%d ", data[i]); }

        return 0;
}