static int
handle_event(struct measurements *m, const struct input_event *ev)
{
if (ev->type == EV_SYN) {
const int idle_reset = 3000000; /* us */
uint64_t last_us = m->us;
m->us = tv2us(&ev->time);
/* reset after pause */
if (last_us + idle_reset < m->us) {
m->max_frequency = 0.0;
m->distance = 0;
} else {
double freq = get_frequency(last_us, m->us);
push_frequency(m, freq);
m->max_frequency = max(freq, m->max_frequency);
return print_current_values(m);
}
return 0;
} else if (ev->type != EV_REL)
return 0;
switch(ev->code) {
case REL_X:
m->distance += ev->value;
break;
}
return 0;
}
unsigned long
medtv(struct timeval *tvarr, size_t tvsize)
{
struct timeval med;
if (tvsize == 0)
return 0;
else if (tvsize == 1)
med = tvarr[tvsize - 1];
else if (tvsize % 2 == 1)
med = tvarr[(tvsize - 1) / 2];
else {
timeradd(&tvarr[(tvsize - 1) / 2], &tvarr[(tvsize - 1) / 2 + 1], &med);
return tv2us(&med) / 2;
}
return tv2us(&med);
}
unsigned long
stddevtv(struct timeval *tvarr, size_t tvsize, unsigned long avg)
{
unsigned long long diffsum;
size_t i;
if (tvsize <= 1)
return 0;
/* get the squared sum of differences from the mean */
for (i = 0, diffsum = 0; i < tvsize; ++i) {
const unsigned long long diff = labs(tv2us(&tvarr[i]) - avg);
diffsum += diff * diff;
}
return (unsigned long)lround(sqrt(((double)diffsum) / tvsize));
}
unsigned long
avgtv(struct timeval *tvarr, size_t tvsize)
{
struct timeval sum, nsum;
size_t i;
if (tvsize == 0)
return 0;
timerclear(&sum);
for (i = 0; i < tvsize; ++i) {
/* don't assume multiple arguments to timer*() can point to same mem. */
timeradd(&sum, &tvarr[i], &nsum);
sum = nsum;
}
return tv2us(&sum) / tvsize;
}
