bbradson
105 lines
2.4 KiB
C#
105 lines
2.4 KiB
C#
// Copyright (c) 2023 bradson
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// This Source Code Form is subject to the terms of the Mozilla Public
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// License, v. 2.0. If a copy of the MPL was not distributed with this
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// file, You can obtain one at https://mozilla.org/MPL/2.0/.
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using System.Diagnostics.CodeAnalysis;
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namespace PerformanceFish.Utility;
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public record struct PooledArray<T> : IDisposable, IEnumerable<T>
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{
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private static T[]?[] _buffers = new T[]?[4];
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private static int _bufferCount;
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private T[] _array;
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private int _length;
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public T[] BackingArray => _array;
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public int Length => _length;
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public int Capacity => _array.Length;
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public T this[int index]
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{
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[MethodImpl(MethodImplOptions.AggressiveInlining)]
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get
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{
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Guard.IsLessThan(index, Length);
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return _array[index];
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}
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[MethodImpl(MethodImplOptions.AggressiveInlining)]
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set
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{
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Guard.IsLessThan(index, Length);
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_array[index] = value;
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}
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}
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public PooledArray() : this(0)
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{
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}
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public PooledArray(int length)
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{
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if (_bufferCount < 1)
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{
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NewBuffer(length);
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}
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else
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{
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ref var bucket = ref _buffers[--_bufferCount];
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_array = bucket!;
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bucket = null;
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if (_array.Length < length)
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ResizeBuffer(length);
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}
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_length = length;
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}
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public PooledArray(ICollection<T> collection) : this(collection.Count) => collection.CopyTo(_array, 0);
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[MethodImpl(MethodImplOptions.AggressiveInlining)]
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public ref T GetReference(int index)
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{
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Guard.IsLessThan(index, Length);
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return ref _array[index];
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}
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[MethodImpl(MethodImplOptions.NoInlining)]
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private void ResizeBuffer(int length) => Array.Resize(ref _array, Mathf.NextPowerOfTwo(length));
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[MemberNotNull(nameof(_array))]
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[MethodImpl(MethodImplOptions.NoInlining)]
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private void NewBuffer(int length) => _array = new T[Mathf.NextPowerOfTwo(length)];
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public void Dispose()
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{
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if (++_bufferCount > _buffers.Length)
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ExpandBuffers(_bufferCount);
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if (_length > 0)
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Array.Clear(_array, 0, _length);
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_buffers[_bufferCount - 1] = _array;
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}
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public void Sort(IComparer<T> comparer) => _array.AsSpan()[.._length].Sort(comparer);
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private static void ExpandBuffers(int minLength)
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{
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var newBuffers = new T[]?[Mathf.NextPowerOfTwo(minLength)];
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Array.Copy(_buffers, newBuffers, _buffers.Length);
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_buffers = newBuffers;
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}
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public IEnumerator<T> GetEnumerator()
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{
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for (var i = 0; i < _length; i++)
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yield return _array[i];
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}
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IEnumerator IEnumerable.GetEnumerator() => GetEnumerator();
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} |