Hastlayer-SDK

namespace Hast.Algorithms.Random;

/// <summary>
/// Implementation of the MWC64X pseudo random number generator algorithm. <see
/// href="http://cas.ee.ic.ac.uk/people/dt10/research/rngs-gpu-mwc64x.html"/> For a PRNG that has lower resource usage
/// but also lower quality see <see cref="RandomLfsr"/>.
/// </summary>
public class RandomMwc64X
{
    /// <summary>
    /// Used for calculating the next state after random number generation.
    /// </summary>
    private const ulong Multiplier = 0x_FFFE_B81B;

    /// <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 ulong State { get; set; } = 0x_CAFEUL; // Just some starting number.

    public uint NextUInt32()
    {
        uint c = (uint)(State >> 32);
        uint x = (uint)State;
        State = (x * Multiplier) + c;
        return x ^ c;
    }
}