/**
* Adds a new key to the set
* @arg s The set to add to
* @arg key The key to add
*/
void set_add(set_t *s, char *key) {
uint32_t i;
uint64_t out[2];
MurmurHash3_x64_128(key, strlen(key), 0, &out);
switch (s->type) {
case EXACT:
// Check if this element is already added
for (i=0; i < s->store.s.count; i++) {
if (out[1] == s->store.s.hashes[i]) return;
}
// Check if we can fit this in the array
if (i < SET_MAX_EXACT) {
s->store.s.hashes[i] = out[1];
s->store.s.count++;
return;
}
// Otherwise, force conversion to HLL
// and purposely fall through to add the
// element to the HLL
convert_exact_to_approx(s);
case APPROX:
hll_add_hash(&s->store.h, out[1]);
break;
}
}
/**
* Adds a new key to the HLL
* @arg h The hll to add to
* @arg key The key to add
*/
void hll_add(hll_t *h, char *key) {
// Compute the hash value of the key
uint64_t out[2];
MurmurHash3_x64_128(key, strlen(key), 0, &out);
// Add the hashed value
hll_add_hash(h, out[1]);
}
END_TEST
START_TEST(test_hll_add_hash)
{
hll_t h;
fail_unless(hll_init(10, &h) == 0);
char buf[100];
for (uint64_t i=0; i < 100; i++) {
hll_add_hash(&h, i ^ rand());
}
fail_unless(hll_destroy(&h) == 0);
}
/**
* Converts a full exact set to an approximate HLL set.
*/
static void convert_exact_to_approx(set_t *s) {
// Store the hashes, as HLL initialization
// will step on the pointer
uint64_t *hashes = s->store.s.hashes;
// Initialize the HLL
s->type = APPROX;
hll_init(s->store.s.precision, &s->store.h);
// Add each hash to the HLL
for (int i=0; i < SET_MAX_EXACT; i++) {
hll_add_hash(&s->store.h, hashes[i]);
}
// Free the array of hashes
free(hashes);
}
