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jameshulse/DeterministicGrouping.cs

Created August 1, 2016 15:31
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  1. jameshulse created this gist Aug 1, 2016.
    16 changes: 16 additions & 0 deletions DeterministicGrouping.cs
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    Original file line number Diff line number Diff line change
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    public static class DeterministicGrouping
    {
    public static bool IsSelected(Guid entropy, ulong numerator, ulong denominator = 100)
    {
    if(numerator > denominator)
    throw new ArgumentOutOfRangeException(nameof(numerator), "The numerator cannot be larger than the denominator.");
    if (numerator <= 0)
    throw new ArgumentOutOfRangeException(nameof(numerator), "The numerator must be a positive non-zero value.");
    if (denominator <= 0)
    throw new ArgumentOutOfRangeException(nameof(denominator), "The denominator must be a positive non-zero value.");

    ulong guidNumericValue = BitConverter.ToUInt32(entropy.ToByteArray().Take(4).ToArray(), 0);

    return guidNumericValue%denominator < numerator;
    }
    }