NullableLongMinMaxAggregationOperator.cs

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using System.Collections.Generic;
using System.Threading;
 
namespace System.Linq.Parallel;
 
internal sealed class NullableLongMinMaxAggregationOperator : InlinedAggregationOperator<long?, long?, long?>
{
    private sealed class NullableLongMinMaxAggregationOperatorEnumerator<TKey> : InlinedAggregationOperatorEnumerator<long?>
    {
        private readonly QueryOperatorEnumerator<long?, TKey> _source;
 
        private readonly int _sign;
 
        internal NullableLongMinMaxAggregationOperatorEnumerator(QueryOperatorEnumerator<long?, TKey> source, int partitionIndex, int sign, CancellationToken cancellationToken)
            : base(partitionIndex, cancellationToken)
        {
            _source = source;
            _sign = sign;
        }
 
        protected override bool MoveNextCore(ref long? currentElement)
        {
            QueryOperatorEnumerator<long?, TKey> source = _source;
            TKey currentKey = default(TKey);
            if (source.MoveNext(ref currentElement, ref currentKey))
            {
                int num = 0;
                if (_sign == -1)
                {
                    long? currentElement2 = null;
                    while (source.MoveNext(ref currentElement2, ref currentKey))
                    {
                        if ((num++ & 0x3F) == 0)
                        {
                            _cancellationToken.ThrowIfCancellationRequested();
                        }
                        if (!currentElement.HasValue || currentElement2 < currentElement)
                        {
                            currentElement = currentElement2;
                        }
                    }
                }
                else
                {
                    long? currentElement3 = null;
                    while (source.MoveNext(ref currentElement3, ref currentKey))
                    {
                        if ((num++ & 0x3F) == 0)
                        {
                            _cancellationToken.ThrowIfCancellationRequested();
                        }
                        if (!currentElement.HasValue || currentElement3 > currentElement)
                        {
                            currentElement = currentElement3;
                        }
                    }
                }
                return true;
            }
            return false;
        }
 
        protected override void Dispose(bool disposing)
        {
            _source.Dispose();
        }
    }
 
    private readonly int _sign;
 
    internal NullableLongMinMaxAggregationOperator(IEnumerable<long?> child, int sign)
        : base(child)
    {
        _sign = sign;
    }
 
    protected override long? InternalAggregate(ref Exception singularExceptionToThrow)
    {
        using IEnumerator<long?> enumerator = GetEnumerator(ParallelMergeOptions.FullyBuffered, suppressOrderPreservation: true);
        if (!enumerator.MoveNext())
        {
            return null;
        }
        long? num = enumerator.Current;
        if (_sign == -1)
        {
            while (enumerator.MoveNext())
            {
                long? current = enumerator.Current;
                if (!num.HasValue || current < num)
                {
                    num = current;
                }
            }
        }
        else
        {
            while (enumerator.MoveNext())
            {
                long? current2 = enumerator.Current;
                if (!num.HasValue || current2 > num)
                {
                    num = current2;
                }
            }
        }
        return num;
    }
 
    protected override QueryOperatorEnumerator<long?, int> CreateEnumerator<TKey>(int index, int count, QueryOperatorEnumerator<long?, TKey> source, object sharedData, CancellationToken cancellationToken)
    {
        return new NullableLongMinMaxAggregationOperatorEnumerator<TKey>(source, index, _sign, cancellationToken);
    }
}