CountAggregationOperator.cs

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using System.Collections.Generic;
using System.Threading;
 
namespace System.Linq.Parallel;
 
internal sealed class CountAggregationOperator<TSource> : InlinedAggregationOperator<TSource, int, int>
{
    private sealed class CountAggregationOperatorEnumerator<TKey> : InlinedAggregationOperatorEnumerator<int>
    {
        private readonly QueryOperatorEnumerator<TSource, TKey> _source;
 
        internal CountAggregationOperatorEnumerator(QueryOperatorEnumerator<TSource, TKey> source, int partitionIndex, CancellationToken cancellationToken)
            : base(partitionIndex, cancellationToken)
        {
            _source = source;
        }
 
        protected override bool MoveNextCore(ref int currentElement)
        {
            TSource currentElement2 = default(TSource);
            TKey currentKey = default(TKey);
            QueryOperatorEnumerator<TSource, TKey> source = _source;
            if (source.MoveNext(ref currentElement2, ref currentKey))
            {
                int num = 0;
                int num2 = 0;
                do
                {
                    if ((num2++ & 0x3F) == 0)
                    {
                        _cancellationToken.ThrowIfCancellationRequested();
                    }
                    num = checked(num + 1);
                }
                while (source.MoveNext(ref currentElement2, ref currentKey));
                currentElement = num;
                return true;
            }
            return false;
        }
 
        protected override void Dispose(bool disposing)
        {
            _source.Dispose();
        }
    }
 
    internal CountAggregationOperator(IEnumerable<TSource> child)
        : base(child)
    {
    }
 
    protected override int InternalAggregate(ref Exception singularExceptionToThrow)
    {
        using IEnumerator<int> enumerator = GetEnumerator(ParallelMergeOptions.FullyBuffered, suppressOrderPreservation: true);
        int num = 0;
        while (enumerator.MoveNext())
        {
            num = checked(num + enumerator.Current);
        }
        return num;
    }
 
    protected override QueryOperatorEnumerator<int, int> CreateEnumerator<TKey>(int index, int count, QueryOperatorEnumerator<TSource, TKey> source, object sharedData, CancellationToken cancellationToken)
    {
        return new CountAggregationOperatorEnumerator<TKey>(source, index, cancellationToken);
    }
}