From 24e269651069e5f13fcde8e467acfa9e96edea62 Mon Sep 17 00:00:00 2001
From: Kamron Batman <3953314+kamronbatman@users.noreply.github.com>
Date: Sat, 22 Oct 2022 14:46:23 -0700
Subject: [PATCH] fix: Adds reset RNG command (#1201)

---
 Projects/Server/Random/Xoshiro256PlusPlus.cs | 13 ++++++++++---
 Projects/UOContent/Commands/ResetRng.cs      | 20 ++++++++++++++++++++
 2 files changed, 30 insertions(+), 3 deletions(-)
 create mode 100644 Projects/UOContent/Commands/ResetRng.cs

diff --git a/Projects/Server/Random/Xoshiro256PlusPlus.cs b/Projects/Server/Random/Xoshiro256PlusPlus.cs
index 205196f66..a19410b76 100644
--- a/Projects/Server/Random/Xoshiro256PlusPlus.cs
+++ b/Projects/Server/Random/Xoshiro256PlusPlus.cs
@@ -14,6 +14,7 @@
  *************************************************************************/
 
 using System;
+using System.Buffers.Binary;
 using System.Runtime.CompilerServices;
 
 namespace Server.Random;
@@ -28,14 +29,20 @@ public class Xoshiro256PlusPlus : BaseRandomSource
 
     private ulong _s0, _s1, _s2, _s3;
 
-    public Xoshiro256PlusPlus() : this((ulong)Environment.TickCount64)
+    public Xoshiro256PlusPlus()
     {
+        Span<byte> states = stackalloc byte[32];
+        RandomSources.SecureSource.NextBytes(states);
+        _s0 = BinaryPrimitives.ReadUInt64LittleEndian(states[..8]);
+        _s1 = BinaryPrimitives.ReadUInt64LittleEndian(states[8..16]);
+        _s2 = BinaryPrimitives.ReadUInt64LittleEndian(states[16..24]);
+        _s3 = BinaryPrimitives.ReadUInt64LittleEndian(states[24..32]);
     }
 
     public Xoshiro256PlusPlus(ulong seed)
     {
         var mix = new SplitMix64(seed);
-        var state = new ulong[4];
+        Span<ulong> state = stackalloc ulong[4];
         mix.FillArray(state);
         _s0 = state[0];
         _s1 = state[1];
@@ -205,7 +212,7 @@ public class SplitMix64
     }
 
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
-    public void FillArray(ulong[] arr)
+    public void FillArray(Span<ulong> arr)
     {
         for (var i = 0; i < arr.Length; i++)
         {
diff --git a/Projects/UOContent/Commands/ResetRng.cs b/Projects/UOContent/Commands/ResetRng.cs
new file mode 100644
index 000000000..9b28d19fc
--- /dev/null
+++ b/Projects/UOContent/Commands/ResetRng.cs
@@ -0,0 +1,20 @@
+using Server.Random;
+
+namespace Server.Commands;
+
+public class ResetRng
+{
+    public static void Initialize()
+    {
+        CommandSystem.Register("RestRng", AccessLevel.Administrator, ResetRng_OnCommand);
+    }
+
+    [Usage("RestRng")]
+    [Description(
+        "Resets the global RNG. Use with care! Do not reset often as this will affect the over-all distribution."
+    )]
+    private static void ResetRng_OnCommand(CommandEventArgs e)
+    {
+        RandomSources.SetRng(new Xoshiro256PlusPlus());
+    }
+}