public void Add(int key, T value)
{
var item = GetRef(key);
if (item != null)
{
Console.WriteLine($"Refreshing: {item.key}");
// Key is already present on the array
var oldNewest = Newest;
Newest = item;
item.next.last = item.last;
item.last.next = item.next;
if (Oldest == item)
{
Oldest = item.last;
Oldest.next = Newest;
}
item.last = Oldest;
item.next = oldNewest;
item.value = value;
oldNewest.last.next = item;
oldNewest.last = item;
}
else
{
var newItem = new LRUItem <T>()
{
key = key,
value = value
};
if (_items.Length + 1 > _cacheSize)
{
Console.WriteLine($"Adding {newItem.key} to a full Array (replacing {Oldest.key})");
// Adding items on a full array
var oldNewest = Newest;
var oldOldest = Oldest;
Newest = newItem;
newItem.last = oldOldest.last;
newItem.next = oldNewest;
oldOldest.last.next = Newest;
oldNewest.last = Newest;
Oldest = oldOldest.last;
var index = Array.IndexOf(_items, oldOldest);
_items[index] = Newest;
}
else
{
Console.WriteLine($"Adding {newItem.key}");
if (_items.Length == 0)
{
// Adding items when array is empty
Newest = newItem;
Oldest = newItem;
newItem.next = newItem;
newItem.last = newItem;
}
// Adding items on a non full array
var oldNewest = Newest;
newItem.last = Oldest;
newItem.next = oldNewest;
oldNewest.last.next = newItem;
oldNewest.last = newItem;
Newest = newItem;
var newItemPosition = _items.Length;
_items = _items.EnsureCapacity(_items.Length + 1);
_items[newItemPosition] = newItem;
}
_items.QuickSort();
}
}
private void RenewCache(LRUItem <T> item)
{
Add(item.key, item.value);
}