From 115ee1a9ec494b10d9d6c5c995cc36305383d7b1 Mon Sep 17 00:00:00 2001
From: Jamie Reece Wilson <me@reece.sx>
Date: Thu, 13 Jul 2023 05:58:53 +0100
Subject: [PATCH] [*] Improve time based RNG failover implementation

---
 Source/RNG/AuRNGEntropy.cpp | 50 +++++++++++++++++++------------------
 1 file changed, 26 insertions(+), 24 deletions(-)

diff --git a/Source/RNG/AuRNGEntropy.cpp b/Source/RNG/AuRNGEntropy.cpp
index ae4b0759..1d106313 100644
--- a/Source/RNG/AuRNGEntropy.cpp
+++ b/Source/RNG/AuRNGEntropy.cpp
@@ -170,47 +170,49 @@ namespace Aurora::RNG
     static AuUInt32 RngTimeBased(AuUInt8 *pBuf, AuUInt32 uLen)
     {
         AuUInt64 t1;
-        int l, acc, bits, a, b, c;
+        int acc, bits, a, b, c;
 
-        l = uLen;
         acc = a = b = c = 0;
         bits = 8;
 
         void *pASLRSeed = &RngTimeBased;
 
-        while (uLen--)
+        for (AU_ITERATE_N(uOffsetInByteStream, uLen))
         {
-            while (bits--) // for each bit in byte
+            for (AU_ITERATE_N(uMultiplePassesForTheFunOfIt, 3))
             {
-                do
+                while (bits--) // for each bit in byte
                 {
-                    t1 = RngTimeClock();
-                    while (t1 == RngTimeClock()) // spin within 1 microseconds
+                    do
                     {
-                        a ^= 1; // flip
-                    }
+                        t1 = RngTimeClock();
+                        while (t1 == RngTimeClock()) // spin within 1 microseconds
+                        {
+                            a ^= 1; // flip
+                        }
 
-                    t1 = RngTimeClock();
-                    while (t1 == RngTimeClock()) // spin within 1 microseconds
-                    {
-                        b ^= 1; // flip
+                        t1 = RngTimeClock();
+                        while (t1 == RngTimeClock()) // spin within 1 microseconds
+                        {
+                            b ^= 1; // flip
+                        }
                     }
+                    while (a == b); // ensure theres enough entropy for a deviation to occur
+                    acc = (acc << 1) | a; // push the first bit state
                 }
-                while (a == b); // ensure theres enough entropy for a deviation to occur
-                acc = (acc << 1) | a; // push the first bit state
+
+                acc = 0;
+                bits = 8;
+
+                c = AuFnv1a32Runtime(&acc, sizeof(acc)) ^
+                    (AuFnv1a32Runtime(&c, sizeof(c)) * kFnv1MagicPrime32) ^
+                    (a ? AuFnv1a32Runtime(&pASLRSeed, sizeof(pASLRSeed)) : 0);
             }
 
-            *pBuf = AuFnv1a32Runtime(&acc, sizeof(acc)) ^
-                AuFnv1a32Runtime(&c, sizeof(c)) ^
-                AuFnv1a32Runtime(&pASLRSeed, sizeof(pASLRSeed));
-
-            c = *pBuf++;
-
-            acc = 0;
-            bits = 8;
+            *pBuf++ = AuUInt8(c);
         }
 
-        return l;
+        return uLen;
     }
 
     AuUInt32 RngGetBytes(AuUInt8 *pBuffer, AuUInt32 uBytes)