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Use segmented arrays internally
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@sharwell
sharwell committed Jul 2, 2021
1 parent 677b2be commit c0c39b1
Showing 1 changed file with 43 additions and 43 deletions.
86 changes: 43 additions & 43 deletions src/Dependencies/Collections/SegmentedHashSet`1.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -47,8 +47,8 @@ private const bool SupportsComparerDevirtualization
private const int ShrinkThreshold = 3;
private const int StartOfFreeList = -3;

private int[]? _buckets;
private Entry[]? _entries;
private SegmentedArray<int> _buckets;
private SegmentedArray<Entry> _entries;
private ulong _fastModMultiplier;
private int _count;
private int _freeList;
Expand Down Expand Up @@ -111,7 +111,7 @@ public SegmentedHashSet(IEnumerable<T> collection, IEqualityComparer<T>? compare

UnionWith(collection);

if (_count > 0 && _entries!.Length / _count > ShrinkThreshold)
if (_count > 0 && _entries.Length / _count > ShrinkThreshold)
{
TrimExcess();
}
Expand Down Expand Up @@ -142,13 +142,13 @@ private void ConstructFrom(SegmentedHashSet<T> source)
return;
}

var capacity = source._buckets!.Length;
var capacity = source._buckets.Length;
var threshold = HashHelpers.ExpandPrime(source.Count + 1);

if (threshold >= capacity)
{
_buckets = (int[])source._buckets.Clone();
_entries = (Entry[])source._entries!.Clone();
_buckets = (SegmentedArray<int>)source._buckets.Clone();
_entries = (SegmentedArray<Entry>)source._entries.Clone();
_freeList = source._freeList;
_freeCount = source._freeCount;
_count = source._count;
Expand All @@ -161,7 +161,7 @@ private void ConstructFrom(SegmentedHashSet<T> source)
var entries = source._entries;
for (var i = 0; i < source._count; i++)
{
ref var entry = ref entries![i];
ref var entry = ref entries[i];
if (entry._next >= -1)
{
AddIfNotPresent(entry._value, out _);
Expand All @@ -184,14 +184,14 @@ public void Clear()
var count = _count;
if (count > 0)
{
Debug.Assert(_buckets != null, "_buckets should be non-null");
Debug.Assert(_entries != null, "_entries should be non-null");
Debug.Assert(_buckets.Length > 0, "_buckets should be non-empty");
Debug.Assert(_entries.Length > 0, "_entries should be non-empty");

Array.Clear(_buckets, 0, _buckets.Length);
SegmentedArray.Clear(_buckets, 0, _buckets.Length);
_count = 0;
_freeList = -1;
_freeCount = 0;
Array.Clear(_entries, 0, count);
SegmentedArray.Clear(_entries, 0, count);
}
}

Expand All @@ -204,10 +204,10 @@ public void Clear()
private int FindItemIndex(T item)
{
var buckets = _buckets;
if (buckets != null)
if (buckets.Length > 0)
{
var entries = _entries;
Debug.Assert(entries != null, "Expected _entries to be initialized");
Debug.Assert(entries.Length > 0, "Expected _entries to be initialized");

uint collisionCount = 0;
var comparer = _comparer;
Expand Down Expand Up @@ -290,16 +290,16 @@ private int FindItemIndex(T item)
[MethodImpl(MethodImplOptions.AggressiveInlining)]
private ref int GetBucketRef(int hashCode)
{
var buckets = _buckets!;
return ref buckets[HashHelpers.FastMod((uint)hashCode, (uint)buckets.Length, _fastModMultiplier)];
var buckets = _buckets;
return ref buckets[(int)HashHelpers.FastMod((uint)hashCode, (uint)buckets.Length, _fastModMultiplier)];
}

public bool Remove(T item)
{
if (_buckets != null)
if (_buckets.Length > 0)
{
var entries = _entries;
Debug.Assert(entries != null, "entries should be non-null");
Debug.Assert(entries.Length > 0, "entries should be non-empty");

uint collisionCount = 0;
var last = -1;
Expand Down Expand Up @@ -390,12 +390,12 @@ public bool Remove(T item)
/// </remarks>
public bool TryGetValue(T equalValue, [MaybeNullWhen(false)] out T actualValue)
{
if (_buckets != null)
if (_buckets.Length > 0)
{
var index = FindItemIndex(equalValue);
if (index >= 0)
{
actualValue = _entries![index]._value;
actualValue = _entries[index]._value;
return true;
}
}
Expand Down Expand Up @@ -801,7 +801,7 @@ public void CopyTo(T[] array, int arrayIndex, int count)
var entries = _entries;
for (var i = 0; i < _count && count != 0; i++)
{
ref var entry = ref entries![i];
ref var entry = ref entries[i];
if (entry._next >= -1)
{
array[arrayIndex++] = entry._value;
Expand All @@ -822,7 +822,7 @@ public int RemoveWhere(Predicate<T> match)
var numRemoved = 0;
for (var i = 0; i < _count; i++)
{
ref var entry = ref entries![i];
ref var entry = ref entries[i];
if (entry._next >= -1)
{
// Cache value in case delegate removes it
Expand Down Expand Up @@ -858,13 +858,13 @@ public int EnsureCapacity(int capacity)
ThrowHelper.ThrowArgumentOutOfRangeException(ExceptionArgument.capacity);
}

var currentCapacity = _entries == null ? 0 : _entries.Length;
var currentCapacity = _entries.Length;
if (currentCapacity >= capacity)
{
return currentCapacity;
}

if (_buckets == null)
if (_buckets.Length == 0)
{
return Initialize(capacity);
}
Expand All @@ -878,16 +878,16 @@ public int EnsureCapacity(int capacity)

private void Resize(int newSize)
{
Debug.Assert(_entries != null, "_entries should be non-null");
Debug.Assert(_entries.Length > 0, "_entries should be non-empty");
Debug.Assert(newSize >= _entries.Length);

var entries = new Entry[newSize];
var entries = new SegmentedArray<Entry>(newSize);

var count = _count;
Array.Copy(_entries, entries, count);
SegmentedArray.Copy(_entries, entries, count);

// Assign member variables after both arrays allocated to guard against corruption from OOM if second fails
_buckets = new int[newSize];
_buckets = new SegmentedArray<int>(newSize);
_fastModMultiplier = HashHelpers.GetFastModMultiplier((uint)newSize);
for (var i = 0; i < count; i++)
{
Expand All @@ -913,7 +913,7 @@ public void TrimExcess()

var newSize = HashHelpers.GetPrime(capacity);
var oldEntries = _entries;
var currentCapacity = oldEntries == null ? 0 : oldEntries.Length;
var currentCapacity = oldEntries.Length;
if (newSize >= currentCapacity)
{
return;
Expand All @@ -926,10 +926,10 @@ public void TrimExcess()
var count = 0;
for (var i = 0; i < oldCount; i++)
{
var hashCode = oldEntries![i]._hashCode; // At this point, we know we have entries.
var hashCode = oldEntries[i]._hashCode; // At this point, we know we have entries.
if (oldEntries[i]._next >= -1)
{
ref var entry = ref entries![count];
ref var entry = ref entries[count];
entry = oldEntries[i];
ref var bucket = ref GetBucketRef(hashCode);
entry._next = bucket - 1; // Value in _buckets is 1-based
Expand All @@ -956,8 +956,8 @@ public void TrimExcess()
private int Initialize(int capacity)
{
var size = HashHelpers.GetPrime(capacity);
var buckets = new int[size];
var entries = new Entry[size];
var buckets = new SegmentedArray<int>(size);
var entries = new SegmentedArray<Entry>(size);

// Assign member variables after both arrays are allocated to guard against corruption from OOM if second fails.
_freeList = -1;
Expand All @@ -974,14 +974,14 @@ private int Initialize(int capacity)
/// <returns>true if the element is added to the <see cref="SegmentedHashSet{T}"/> object; false if the element is already present.</returns>
private bool AddIfNotPresent(T value, out int location)
{
if (_buckets == null)
if (_buckets.Length == 0)
{
Initialize(0);
}
Debug.Assert(_buckets != null);
Debug.Assert(_buckets.Length > 0);

var entries = _entries;
Debug.Assert(entries != null, "expected entries to be non-null");
Debug.Assert(entries.Length > 0, "expected entries to be non-empty");

var comparer = _comparer;
int hashCode;
Expand Down Expand Up @@ -1068,7 +1068,7 @@ private bool AddIfNotPresent(T value, out int location)
{
index = _freeList;
_freeCount--;
Debug.Assert((StartOfFreeList - entries![_freeList]._next) >= -1, "shouldn't overflow because `next` cannot underflow");
Debug.Assert((StartOfFreeList - entries[_freeList]._next) >= -1, "shouldn't overflow because `next` cannot underflow");
_freeList = StartOfFreeList - entries[_freeList]._next;
}
else
Expand All @@ -1085,7 +1085,7 @@ private bool AddIfNotPresent(T value, out int location)
}

{
ref var entry = ref entries![index];
ref var entry = ref entries[index];
entry._hashCode = hashCode;
entry._next = bucket - 1; // Value in _buckets is 1-based
entry._value = value;
Expand Down Expand Up @@ -1147,7 +1147,7 @@ private void IntersectWithHashSetWithSameComparer(SegmentedHashSet<T> other)
var entries = _entries;
for (var i = 0; i < _count; i++)
{
ref var entry = ref entries![i];
ref var entry = ref entries[i];
if (entry._next >= -1)
{
var item = entry._value;
Expand All @@ -1167,7 +1167,7 @@ private void IntersectWithHashSetWithSameComparer(SegmentedHashSet<T> other)
/// </summary>
private unsafe void IntersectWithEnumerable(IEnumerable<T> other)
{
Debug.Assert(_buckets != null, "_buckets shouldn't be null; callers should check first");
Debug.Assert(_buckets.Length > 0, "_buckets shouldn't be empty; callers should check first");

// Keep track of current last index; don't want to move past the end of our bit array
// (could happen if another thread is modifying the collection).
Expand All @@ -1193,7 +1193,7 @@ private unsafe void IntersectWithEnumerable(IEnumerable<T> other)
// FindFirstUnmarked method.
for (var i = 0; i < originalCount; i++)
{
ref var entry = ref _entries![i];
ref var entry = ref _entries[i];
if (entry._next >= -1 && !bitHelper.IsMarked(i))
{
Remove(entry._value);
Expand Down Expand Up @@ -1281,7 +1281,7 @@ private unsafe void SymmetricExceptWithEnumerable(IEnumerable<T> other)
{
if (itemsToRemove.IsMarked(i))
{
Remove(_entries![i]._value);
Remove(_entries[i]._value);
}
}
}
Expand Down Expand Up @@ -1324,7 +1324,7 @@ private unsafe (int UniqueCount, int UnfoundCount) CheckUniqueAndUnfoundElements
return (UniqueCount: 0, UnfoundCount: numElementsInOther);
}

Debug.Assert((_buckets != null) && (_count > 0), "_buckets was null but count greater than 0");
Debug.Assert((_buckets.Length > 0) && (_count > 0), "_buckets was empty but count greater than 0");

var originalCount = _count;
int intArrayLength = BitHelper.ToIntArrayLength(originalCount);
Expand Down Expand Up @@ -1409,7 +1409,7 @@ public bool MoveNext()
// dictionary.count+1 could be negative if dictionary.count is int.MaxValue
while ((uint)_index < (uint)_hashSet._count)
{
ref var entry = ref _hashSet._entries![_index++];
ref var entry = ref _hashSet._entries[_index++];
if (entry._next >= -1)
{
_current = entry._value;
Expand Down

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