/// <summary>
/// set the comparer to use when getting the hash code.
/// If comparer is null, the current comparer is not changed.
/// </summary>
public static void SetComparer <TKey>(SimpleSet <TKey> Set, IEqualityComparer <TKey> comparer)
{
if (comparer != null)
{
Set.Comparer = comparer;
}
}
/// <summary>
/// Adds the value to the set using the key.
/// If replace is true and the key is already present on the set, we will replace the value,
/// if false, we will return false to signal the failure.
/// </summary>
public static void Add <TKey>(SimpleSet <TKey> Set, TKey key)
{
var hash = Set.Comparer.GetHashCode(key);
var index = (hash & int.MaxValue) % Set.Capacity;
var inserted = false;
var entry = Set.Entries[index];
if (entry != null)
{
// If we find a entry with the given key, validate if it's the same key
// this is needed because two keys can produce the same hash
if (entry.HashCode != hash && !Set.Comparer.Equals(key, entry.Key))
{
// It's a collision, create an entry and add to the linked list of collisions
var newEntry = CreateEntry(Set, key, hash);
// Find the last element of the collision chain
while (entry.Next != null)
{
entry = entry.Next;
}
entry.Next = newEntry;
inserted = true;
if (Set.Count >= Set.Capacity)
{
Expand(Set);
}
}
}
// Did not found, create and add an entry
else
{
var newEntry = CreateEntry(Set, key, hash);
if (Set.Count >= Set.Capacity)
{
Expand(Set);
}
Set.Entries[index] = newEntry;
inserted = true;
}
if (inserted)
{
Set.Count++;
}
}
/// <summary>
/// Creates a new set entry with the given values.
/// </summary>
private static SetEntry <TKey> CreateEntry <TKey>(SimpleSet <TKey> Set, TKey key, int hash)
{
SetEntry <TKey> newEntry;
if (Set.EntryPool.Count > 0)
{
newEntry = Set.EntryPool[Set.EntryPool.Count - 1];
SList.RemoveLast(Set.EntryPool); // remove last for better perfomance
}
else
{
newEntry = new SetEntry <TKey>();
}
newEntry.Key = key;
newEntry.HashCode = hash;
return(newEntry);
}
/// <summary>
/// Creates a fake hash set with the given capacity.
/// This will also create an pool of SetEntry (the internal class used to store elements
/// on the array) to reduce garbage generation and improve performance.
/// If preWarmPool is true, this will pre-instantiate the elements on the pool.
/// If preWarmPool is false, this will only create a SimpleSet of size 'size' and
/// pool removed elements from the set for later reuse.
/// </summary>
public static SimpleSet <TKey> Create <TKey>(int size, bool preWarmPool)
{
var Set = new SimpleSet <TKey>();
Set.Count = 0;
Set.Capacity = GetNextLength(size);
Set.Entries = new SetEntry <TKey> [Set.Capacity];
Set.Comparer = EqualityComparer <TKey> .Default;
Set.Enumerator = new SimpleSetEnumerator <TKey>();
Set.Enumerator.Set = Set;
Set.EntryPool = SList.Create <SetEntry <TKey> >(size);
if (preWarmPool)
{
for (int i = 0; i < size; i++)
{
Set.EntryPool[i] = new SetEntry <TKey>();
}
}
return(Set);
}
