utils.c

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

/* Returns the number of microseconds since Unix epoch. */
long long microseconds(void) {
    struct timeval tv;
    long long mst;
    gettimeofday(&tv, NULL);
    mst = ((long long)tv.tv_sec)*1000000;
    mst += tv.tv_usec;
    return mst;
}

/* Convert number of bytes into a human readable string of the form:
 * 100B, 2G, 100M, 4K, and so forth. */
void bytesToHuman(char *s, long long n) {
    double d;

    if (n < 0) {
        *s = '-';
        s++;
        n = -n;
    }
    if (n < 1024) {
        /* Bytes */
        sprintf(s,"%lluB",n);
        return;
    } else if (n < (1024*1024)) {
        d = (double)n/(1024);
        sprintf(s,"%.2fK",d);
    } else if (n < (1024LL*1024*1024)) {
        d = (double)n/(1024*1024);
        sprintf(s,"%.2fM",d);
    } else if (n < (1024LL*1024*1024*1024)) {
        d = (double)n/(1024LL*1024*1024);
        sprintf(s,"%.2fG",d);
    }
}