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chained.cpp
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chained.cpp
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#ifdef DEFAULT
#include "chained.h"
ChainedHashmap::ChainedHashmap() {
this->hashpower = -1; // not initialized
this->hmsize = 0;
this->cardinality = 0;
this->dict = NULL;
this->entries = NULL;
this->entriesOffset = 0;
}
void ChainedHashmap::initHashpower(int hashpower) {
this->hashpower = hashpower;
this->hmsize = pow(2, hashpower);
this->dict = (KV**)malloc(sizeof(KV*)*hmsize);
this->entries = (KV*)malloc(sizeof(KV)*hmsize*20); // safety factor
memset(this->dict, 0, sizeof(KV*)*hmsize);
memset(this->entries, 0, sizeof(KV)*hmsize*20);
entriesOffset = 0;
}
void ChainedHashmap::bulkLoad(ulong *keys, ulong num_keys) {
for (ulong i=0; i<num_keys; i++) {
_setFinal(keys[i], _random());
}
this->cardinality = num_keys;
}
Metrics ChainedHashmap::processRequests(HashmapReq *reqs, ulong count) {
Metrics m;
m.displacement = displacement;
getMetricsStart(m);
for (ulong i=0; i<count; i++) {
switch (reqs[i].reqType) {
case FETCH_REQ:
_fetch(&reqs[i]);
break;
case INSERT_REQ:
_insert(&reqs[i]);
break;
case DELETE_REQ:
_delete(&reqs[i]);
break;
default:
break;
}
}
getMetricsEnd(m);
m.displacement = displacement - m.displacement;
return m;
}
void ChainedHashmap::rehash() {
if (cardinality < 1.5*hmsize && cardinality > 0.5*hmsize) {
return;
}
cout << "Rehashing triggered at numReqs " << this->numReqs << " cardinality: " << this->cardinality << endl;
KV* old_entries = entries;
KV** old_dict = dict;
ulong old_hmsize = hmsize;
this->hashpower = _getHashpower();
hmsize = pow(2, hashpower);
dict = (KV**)malloc(sizeof(KV*)*hmsize);
entries = (KV*)malloc(sizeof(KV)*hmsize*20);
memset(this->dict, 0, sizeof(KV*)*hmsize);
memset(this->entries, 0, sizeof(KV)*hmsize*20);
entriesOffset = 0;
KV* ptr;
for (ulong i=0; i<old_hmsize; i++) {
ptr = old_dict[i];
while (ptr != NULL) {
_setFinal(ptr->key, ptr->value);
ptr = ptr->next;
}
}
std::free(old_entries);
std::free(old_dict);
}
void ChainedHashmap::free() {
std::free(dict);
std::free(entries);
}
inline ulong ChainedHashmap::_random() {
ulong r = (ulong)random();
r = r<<31;
r = r + (ulong)random();
return r;
}
inline ulong ChainedHashmap::_murmurHash(ulong h) {
h ^= h >> 33;
h *= 0xff51afd7ed558ccd;
h ^= h >> 33;
h *= 0xc4ceb9fe1a85ec53;
h ^= h >> 33;
h = h >> (64 - hashpower);
return h;
}
inline void ChainedHashmap::_fetch(HashmapReq *r) {
ulong h = _murmurHash(r->key);
KV* ptr = dict[h];
while (ptr && ptr->key != r->key) {
#if _COUNT_DISP_
displacement += 1;
#endif
ptr = ptr->next;
}
if (ptr == NULL) return;
#if _COUNT_DISP_
displacement += 1;
#endif
r->value = ptr->value;
numReqs += 1;
}
inline void ChainedHashmap::_insert(HashmapReq *r) {
ulong h = _murmurHash(r->key);
KV* ptr = dict[h];
while (ptr && ptr->key != r->key) {
ptr = ptr->next;
}
if (ptr != NULL) {
ptr->value = r->value;
return;
}
// else, insert
_setFinal(r->key, r->value);
cardinality += 1;
numReqs += 1;
}
inline void ChainedHashmap::_delete(HashmapReq *r) {
ulong h = _murmurHash(r->key);
KV *prev, *cur;
cur = prev = dict[h];
while (cur != NULL && cur->key != r->key) {
prev = cur;
cur = cur->next;
}
if (cur == NULL) return;
if (prev != cur) {
prev->next = cur->next;
} else {
dict[h] = cur->next;
}
cardinality -= 1;
numReqs += 1;
}
inline void ChainedHashmap::_setFinal(ulong key, ulong value) {
entries[entriesOffset].key = key;
entries[entriesOffset].value = value;
ulong h = _murmurHash(key);
entries[entriesOffset].next = dict[h];
dict[h] = &entries[entriesOffset];
entriesOffset += 1;
}
inline ulong ChainedHashmap::_getTimeDiff(struct timespec startTime, struct timespec endTime) {
return (ulong)((endTime.tv_sec - startTime.tv_sec)*1000000 +
double(endTime.tv_nsec - startTime.tv_nsec)/1000);
}
inline int ChainedHashmap::_getHashpower() {
int hashpower = 0;
while (pow(2, hashpower) < this->cardinality/1.5) {
hashpower += 1;
}
return hashpower;
}
#endif // DEFAULT