/// <summary>
/// CONSTRUCTOR
/// </summary>
public CuckooHashTable()
{
_size = 0;
_numberOfRehashes = 0;
_randomizer = new Random();
_collection = new CHashEntry <TKey, TValue> [DEFAULT_CAPACITY];
_universalHashingFamily = new UniversalHashingFamily(NUMBER_OF_HASH_FUNCTIONS);
}
/// <summary>
/// Inserts a key-value pair into hash table.
/// </summary>
private void _insertHelper(TKey key, TValue value)
{
int COUNT_LIMIT = 100;
var newEntry = new CHashEntry <TKey, TValue>(key, value, isActive: true);
while (true)
{
int position, lastPosition = -1;
for (int count = 0; count < COUNT_LIMIT; count++)
{
// The hash functions numbers are indexed from 1 not zero
for (int i = 1; i <= NUMBER_OF_HASH_FUNCTIONS; i++)
{
position = _cuckooHash(key, i);
if (!_isActive(position))
{
_collection[position] = newEntry;
// Increment size
++_size;
return;
}
}
// Eviction strategy:
// No available spot was found. Choose a random one.
int j = 0;
do
{
position = _cuckooHash(key, _randomizer.Next(1, NUMBER_OF_HASH_FUNCTIONS));
} while (position == lastPosition && j++ < NUMBER_OF_HASH_FUNCTIONS);
// SWAP ENTRY
lastPosition = position;
var temp = _collection[position];
_collection[position] = newEntry;
newEntry = temp;
}//end-for
if (++_numberOfRehashes > ALLOWED_REHASHES)
{
// Expand the table.
_expandCapacity(_collection.Length + 1);
// Reset number of rehashes.
_numberOfRehashes = 0;
}
else
{
// Rehash the table with the same current size.
_rehash();
}
}//end-while
}