#include <netinet/in_stat.h>
#define IN_STAT_ACTIVITY_GRANULARITY 8
#define IN_STAT_ACTIVITY_TIME_SEC_SHIFT 3
#define IN_STAT_ACTIVITY_BITMAP_TOTAL_SIZE ((uint64_t) 128)
#define IN_STAT_ACTIVITY_BITMAP_FIELD_SIZE ((uint64_t) 64)
#define IN_STAT_ACTIVITY_TOTAL_TIME ((uint64_t) (8 * 128))
#define IN_STAT_SET_MOST_SIGNIFICANT_BIT ((u_int64_t )0x8000000000000000)
void
in_stat_set_activity_bitmap(activity_bitmap_t *activity, uint64_t now)
{
uint64_t elapsed_time, slot;
uint64_t *bitmap;
if (activity->start == 0) {
activity->start = now - (now % IN_STAT_ACTIVITY_GRANULARITY);
}
elapsed_time = now - activity->start;
slot = elapsed_time >> IN_STAT_ACTIVITY_TIME_SEC_SHIFT;
if (slot < IN_STAT_ACTIVITY_BITMAP_TOTAL_SIZE) {
if (slot < IN_STAT_ACTIVITY_BITMAP_FIELD_SIZE) {
bitmap = &activity->bitmap[0];
} else {
bitmap = &activity->bitmap[1];
slot -= IN_STAT_ACTIVITY_BITMAP_FIELD_SIZE;
}
*bitmap |= (((u_int64_t) 1) << slot);
} else {
if (slot >= (IN_STAT_ACTIVITY_BITMAP_TOTAL_SIZE * 2)) {
activity->start = now - IN_STAT_ACTIVITY_TOTAL_TIME;
activity->bitmap[0] = activity->bitmap[1] = 0;
} else {
uint64_t shift =
slot - (IN_STAT_ACTIVITY_BITMAP_TOTAL_SIZE - 1);
activity->start +=
(shift << IN_STAT_ACTIVITY_TIME_SEC_SHIFT);
if (shift > IN_STAT_ACTIVITY_BITMAP_FIELD_SIZE) {
activity->bitmap[0] = activity->bitmap[1];
activity->bitmap[1] = 0;
shift -= IN_STAT_ACTIVITY_BITMAP_FIELD_SIZE;
if (shift == IN_STAT_ACTIVITY_BITMAP_FIELD_SIZE) {
activity->bitmap[0] = 0;
} else {
activity->bitmap[0] >>= shift;
}
} else {
uint64_t mask_lower, tmp;
uint64_t b1_low, b0_high;
tmp = (((uint64_t)1) << (shift - 1));
mask_lower = ((tmp - 1) ^ tmp);
activity->bitmap[0] >>= shift;
b1_low = (activity->bitmap[1] & mask_lower);
b0_high = (b1_low <<
(IN_STAT_ACTIVITY_BITMAP_FIELD_SIZE -
shift));
activity->bitmap[0] |= b0_high;
activity->bitmap[1] >>= shift;
}
}
activity->bitmap[1] |= IN_STAT_SET_MOST_SIGNIFICANT_BIT;
}
}