RangeManager.cs

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namespace System.Threading.Tasks;
 
internal sealed class RangeManager
{
    internal readonly IndexRange[] _indexRanges;
 
    internal readonly bool _use32BitCurrentIndex;
 
    internal int _nCurrentIndexRangeToAssign;
 
    internal long _nStep;
 
    internal RangeManager(long nFromInclusive, long nToExclusive, long nStep, int nNumExpectedWorkers)
    {
        _nCurrentIndexRangeToAssign = 0;
        _nStep = nStep;
        if (nNumExpectedWorkers == 1)
        {
            nNumExpectedWorkers = 2;
        }
        ulong num = (ulong)(nToExclusive - nFromInclusive);
        ulong num2 = num / (ulong)nNumExpectedWorkers;
        num2 -= num2 % (ulong)nStep;
        if (num2 == 0L)
        {
            num2 = (ulong)nStep;
        }
        int num3 = (int)(num / num2);
        if (num % num2 != 0L)
        {
            num3++;
        }
        long num4 = (long)num2;
        _use32BitCurrentIndex = IntPtr.Size == 4 && num4 <= int.MaxValue;
        _indexRanges = new IndexRange[num3];
        long num5 = nFromInclusive;
        for (int i = 0; i < num3; i++)
        {
            _indexRanges[i]._nFromInclusive = num5;
            _indexRanges[i]._nSharedCurrentIndexOffset = null;
            _indexRanges[i]._bRangeFinished = 0;
            num5 += num4;
            if (num5 < num5 - num4 || num5 > nToExclusive)
            {
                num5 = nToExclusive;
            }
            _indexRanges[i]._nToExclusive = num5;
        }
    }
 
    internal RangeWorker RegisterNewWorker()
    {
        int nInitialRange = (Interlocked.Increment(ref _nCurrentIndexRangeToAssign) - 1) % _indexRanges.Length;
        return new RangeWorker(_indexRanges, nInitialRange, _nStep, _use32BitCurrentIndex);
    }
}