Hastlayer-SDK

namespace Hast.Algorithms.Random;

/// <summary>
/// A linear-feedback shift register pseudo random number generator with a 16b state. For details check out <see
/// href="https://en.wikipedia.org/wiki/Linear-feedback_shift_register">Wikipedia</see>. Also see <see
/// href="https://en.wikipedia.org/wiki/Xorshift"/>.
/// </summary>
public class RandomXorshiftLfsr16
{
    /// <summary>
    /// Gets or sets the current inner state of the random number generator. If you set it when instantiating the object
    /// then it'll serve as a seed.
    /// </summary>
    /// <remarks>
    /// <para>By not using a constructor the whole class can be inlined for maximal performance.</para>
    /// </remarks>
    public ushort State { get; set; } = 49_813; // Just some starting number.

    public ushort NextUInt16()
    {
        State ^= (ushort)(State >> 7);
        State ^= (ushort)(State << 9);
        State ^= (ushort)(State >> 13);

        return State;
    }
}