int LRUCache::get(int key) {
hash_iterator hash_iter = hash_map_.find(key);
if (hash_iter == hash_map_.end()) return -1;
int value = hash_iter->second->value;
remove(hash_iter->second);
append(key, value);
return value;
}
void LRUCache::set(int key, int value) {
hash_iterator hash_iter = hash_map_.find(key);
if (hash_iter != hash_map_.end()) {
remove(hash_iter->second);
append(key, value);
return;
}
append(key, value);
while (lst_.size() > capacity_) {
remove(--lst_.end());
}
}
virtual size_t get_addr_hash (void const* p)
{
//!!! accept 'table size' to do 'hash % table_size'
// will give more information for state exploration
hash_map_t::iterator iter (hash_map_.find(p));
if (iter != hash_map_.end() && iter->first == p)
{
return iter->second;
}
else
{
//!!! distribute hashes more randomly, use rand()
size_t hash = hash_seq_++;
hash_map_.insert(std::make_pair(p, hash));
return hash;
}
}
void LRUCache::remove(elem_iterator it) {
hash_map_.erase(it->key);
lst_.erase(it);
}
void LRUCache::append(int key, int value) {
lst_.emplace_front(key, value);
pair<hash_iterator, bool> ret =
hash_map_.insert(hash_value_type(key, lst_.begin()));
if (!ret.second) ret.first->second = lst_.begin();
}
