HashRepartitionStream.cs

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using System.Collections.Generic;
 
namespace System.Linq.Parallel;
 
internal abstract class HashRepartitionStream<TInputOutput, THashKey, TOrderKey> : PartitionedStream<Pair<TInputOutput, THashKey>, TOrderKey>
{
    private readonly IEqualityComparer<THashKey> _keyComparer;
 
    private readonly IEqualityComparer<TInputOutput> _elementComparer;
 
    private readonly int _distributionMod;
 
    internal HashRepartitionStream(int partitionsCount, IComparer<TOrderKey> orderKeyComparer, IEqualityComparer<THashKey> hashKeyComparer, IEqualityComparer<TInputOutput> elementComparer)
        : base(partitionsCount, orderKeyComparer, OrdinalIndexState.Shuffled)
    {
        _keyComparer = hashKeyComparer;
        _elementComparer = elementComparer;
        checked
        {
            for (_distributionMod = 503; _distributionMod < partitionsCount; _distributionMod *= 2)
            {
            }
        }
    }
 
    internal int GetHashCode(TInputOutput element)
    {
        return (0x7FFFFFFF & ((element != null) ? (_elementComparer?.GetHashCode(element) ?? element.GetHashCode()) : 0)) % _distributionMod;
    }
 
    internal int GetHashCode(THashKey key)
    {
        return (0x7FFFFFFF & ((key != null) ? (_keyComparer?.GetHashCode(key) ?? key.GetHashCode()) : 0)) % _distributionMod;
    }
}