public void Add(int key, string value)
{
if (values.ContainsKey(key))
{
values[key].UpdateValue(value);
PromoteEntry(values[key]);
return;
}
if (entriesCount == capacity)
{
var evictedEntry = frequencies[minFrequency].RemoveTail();
values.Remove(evictedEntry.Key);
if (frequencies[minFrequency].IsEmpty)
{
frequencies.Remove(minFrequency);
}
entriesCount--;
}
if (!frequencies.ContainsKey(DefaultFrequency))
{
frequencies[DefaultFrequency] = new CacheDoubleLinkedList();
}
var newEntry = new CacheEntry(key, value);
frequencies[DefaultFrequency].InsertToHead(newEntry);
values[key] = newEntry;
nodeFrequencies[newEntry] = DefaultFrequency;
minFrequency = DefaultFrequency;
entriesCount++;
}
public Lru(int capacity)
{
values = new Dictionary <int, CacheEntry>();
this.capacity = capacity;
entriesCount = 0;
list = new CacheDoubleLinkedList();
}
private void PromoteEntry(CacheEntry cacheEntry)
{
var currentFrequency = nodeFrequencies[cacheEntry];
frequencies[currentFrequency].Remove(cacheEntry);
if (frequencies[currentFrequency].IsEmpty)
{
frequencies.Remove(currentFrequency);
}
var newFrequency = ++currentFrequency;
if (!frequencies.ContainsKey(newFrequency))
{
frequencies[newFrequency] = new CacheDoubleLinkedList();
}
frequencies[newFrequency].InsertToHead(cacheEntry);
nodeFrequencies[cacheEntry] = newFrequency;
}