void resize() {
int new_length = 4;
while(new_length < elems_) {
new_length <<= 1;
}
HashNode** new_list = new HashNode*[new_length];
memset(new_list, 0, sizeof(new_list[0]) * new_length);
int count = 0;
for(int i=0; i<length_; ++i) {
HashNode* now = list_[i];
while(now != NULL) {
HashNode* next = now->next_hash;
Slice key = now->key();
int hash = now->hash;
HashNode** ptr = &new_list[hash & (new_length - 1)];
now->next_hash = *ptr;
*ptr = now;
now = next;
count++;
}
}
assert(elems_ == count);
delete[] list_;
list_ = new_list;
length_ = new_length;
}
HashNode* insert(const Slice& key, int& hit_id, int& rep_id) {
HashNode* e = reinterpret_cast<HashNode*>(malloc(sizeof(HashNode) - 1 + key.size()));
e->key_length = key.size();
e->hash = hash_slice(key);
memcpy(e->key_data, key.data(), key.size());
lru_append(e);
HashNode* old = table_.insert(e);
if(old != NULL) {
//命中缓存
e->cache_id = old->cache_id;
hit_id = e->cache_id;
rep_id = -1;
lru_remove(old);
lru_release(old);
//update hit ratio
hit_cnt++;
}
else {
//没有命中缓存
hit_id = -1;
//如果当前的缓存数量超过capacity，把lru_后面的那个缓存单元淘汰掉
if(table_.size() > capacity_) {
HashNode* cursor = lru_.next;
lru_remove(cursor);
table_.remove(cursor->key(), cursor->hash);
e->cache_id = cursor->cache_id;
lru_release(cursor);
}
else {
e->cache_id = last_id++; //TODO 会无限增长?
}
rep_id = e->cache_id;
//update hit ratio
set_cnt++;
}
return e;
}