public TValue this[TKey key]
{
get
{
if (!_isDictionaryFallback)
{
var existingItem = _slots[CustomCollectionsHelpers.PositiveHashCode(key) % _slotsLength];
if (existingItem.Key != null && key.Equals(existingItem.Key))
{
return(existingItem.Value);
}
}
return(_dictionary[key]);
}
set { throw new NotSupportedException(); }
}
public ReadonlyHashSet(ISet <T> items)
{
_hashSet = new HashSet <T>(items);
_slotsLength = CustomCollectionsHelpers.Primes.FirstOrDefault(_ => IsNoCollision(items, _));
if (_slotsLength == 0)
{
_isHashSetFallback = true;
}
else
{
_slots = new T[_slotsLength];
foreach (var item in items)
{
_slots[CustomCollectionsHelpers.PositiveHashCode(item) % _slots.Length] = item;
}
}
}
public ReadonlyDictionary(IDictionary <TKey, TValue> items)
{
_dictionary = items;
_slotsLength = CustomCollectionsHelpers.Primes.FirstOrDefault(_ => IsNoCollision(items, _));
if (_slotsLength == 0)
{
_isDictionaryFallback = true;
}
else
{
_slots = new Entry[_slotsLength];
foreach (var item in items)
{
_slots[CustomCollectionsHelpers.PositiveHashCode(item.Key) % _slotsLength].Key = item.Key;
_slots[CustomCollectionsHelpers.PositiveHashCode(item.Key) % _slotsLength].Value = item.Value;
}
}
}
private bool IsNoCollision(IDictionary <TKey, TValue> items, int prime)
{
return(items.Select(_ => CustomCollectionsHelpers.PositiveHashCode(_.Key) % prime).Distinct().Count() == items.Count);
}
private bool IsNoCollision(ISet <T> items, int prime)
{
return(items.Select(_ => CustomCollectionsHelpers.PositiveHashCode(_) % prime).Distinct().Count() == items.Count);
}
