From 4703264c5754290f58e4ff7361a28d3f47dc49e9 Mon Sep 17 00:00:00 2001
From: Reece <me@reece.sx>
Date: Fri, 1 Oct 2021 17:54:55 +0100
Subject: [PATCH] [+] Added 64bit rng seed support [*] Cryptographically unsafe
 RNG is marginally less dangerous; use secure rng for the entire base seed
 instead of seeding using 32bit mt

---
 Include/Aurora/RNG/IRandomDevice.hpp |  9 ++++++++-
 Source/RNG/RandomDevice.cpp          | 14 +++++++++++++-
 Source/RNG/WELL.cpp                  | 19 +++++++++++++++++++
 Source/RNG/WELL.hpp                  |  1 +
 4 files changed, 41 insertions(+), 2 deletions(-)

diff --git a/Include/Aurora/RNG/IRandomDevice.hpp b/Include/Aurora/RNG/IRandomDevice.hpp
index f84788fe..a02a32dd 100644
--- a/Include/Aurora/RNG/IRandomDevice.hpp
+++ b/Include/Aurora/RNG/IRandomDevice.hpp
@@ -64,13 +64,20 @@ namespace Aurora::RNG
     {
         bool secure;
         AuOptional<AuUInt32> seed;
-
+        AuOptional<AuUInt64> seed64;
+        
         inline void SetSeed(AuUInt32 seed)
         {
             this->seed = seed;
             this->secure = false;
         }
 
+        inline void SetSeed64(AuUInt64 seed)
+        {
+            this->seed64 = seed;
+            this->secure = false;
+        }
+
         inline void SetCSRNG()
         {
             this->secure = true;
diff --git a/Source/RNG/RandomDevice.cpp b/Source/RNG/RandomDevice.cpp
index 0b811e96..bd44c76c 100644
--- a/Source/RNG/RandomDevice.cpp
+++ b/Source/RNG/RandomDevice.cpp
@@ -40,7 +40,19 @@ namespace Aurora::RNG
         this->def_ = def;
         if (!def.secure)
         {
-            this->fast_ = WELL_SeedRand(def.seed.value_or(Aurora::RNG::RngTmpl<false, AuUInt32>()));
+            if (def.seed)
+            {
+                this->fast_ = WELL_SeedRand(def.seed.value());
+            }
+            else if (def.seed64)
+            {
+                this->fast_ = WELL_SeedRand64(def.seed64.value());
+            }
+            else
+            {
+                this->fast_ = {};
+                RNG::RngArray<false>(this->fast_.state);
+            }
         }
     }
 
diff --git a/Source/RNG/WELL.cpp b/Source/RNG/WELL.cpp
index 3b614e3c..b0ac7db9 100644
--- a/Source/RNG/WELL.cpp
+++ b/Source/RNG/WELL.cpp
@@ -26,6 +26,18 @@ inline static void WELL_SeedRand(WELLRand *rand, AuUInt32 seed)
     }
 }
 
+inline static void WELL_SeedRand64(WELLRand *rand, AuUInt64 seed)
+{
+    MTRand mtrand = MT_SeedRand(seed & 0xffffffff);
+    MTRand mtrand2 = MT_SeedRand(seed >> 32);
+    
+    for (unsigned int i = 0; i < 16; i += 2)
+    {
+        rand->state[i] = MT_NextLong(&mtrand);
+        rand->state[i + 1] = MT_NextLong(&mtrand2);
+    }
+}
+
 /**
  * Creates a new random number generator from a given seed.
  */
@@ -36,6 +48,13 @@ WELLRand WELL_SeedRand(AuUInt32 seed)
     return rand;
 }
 
+WELLRand WELL_SeedRand64(AuUInt64 seed)
+{
+    WELLRand rand {};
+    WELL_SeedRand64(&rand, seed);
+    return rand;
+}
+
 /**
  * Generates a pseudo-randomly generated long.
  */
diff --git a/Source/RNG/WELL.hpp b/Source/RNG/WELL.hpp
index 5b782f1d..94959778 100644
--- a/Source/RNG/WELL.hpp
+++ b/Source/RNG/WELL.hpp
@@ -8,5 +8,6 @@ struct WELLRand
 };
 
 WELLRand WELL_SeedRand(AuUInt32 seed);
+WELLRand WELL_SeedRand64(AuUInt64 seed);
 AuUInt32 WELL_NextLong(WELLRand* rand);
 void WELL_NextBytes(WELLRand *rand, void *in, AuUInt32 length);
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