From d501a1cf717cdfacd04e2de6074d4d16b326cee5 Mon Sep 17 00:00:00 2001
From: goyuken <goyuken@4bbf4f03-6f44-549e-7e59-35d4b0962838>
Date: Fri, 13 Jun 2014 19:32:36 +0000
Subject: [PATCH] speed up overall load speed of N64 text savestates
 (uncommonly used) by 25%

---
 BizHawk.Common/Extensions/Extensions.cs | 17 ++++++++++++++---
 1 file changed, 14 insertions(+), 3 deletions(-)

diff --git a/BizHawk.Common/Extensions/Extensions.cs b/BizHawk.Common/Extensions/Extensions.cs
index 6342694e21..d03ec15893 100644
--- a/BizHawk.Common/Extensions/Extensions.cs
+++ b/BizHawk.Common/Extensions/Extensions.cs
@@ -363,11 +363,22 @@ namespace BizHawk.Common
 			}
 		}
 
-		public static void ReadFromHexFast(this byte[] buffer, string hex)
+		public static unsafe void ReadFromHexFast(this byte[] buffer, string hex)
 		{
-			for (int i = 0; i < buffer.Length && i * 2 < hex.Length; i++)
+			if (buffer.Length * 2 != hex.Length)
+				throw new Exception("Data size mismatch");
+			int count = buffer.Length;
+			fixed (byte* _dst = buffer)
+			fixed (char* _src = hex)
 			{
-				buffer[i] = (byte)(Hex2Int(hex[i * 2]) * 16 + Hex2Int(hex[i * 2 + 1]));
+				byte* dst = _dst;
+				char* src = _src;
+				while (count > 0)
+				{
+					// in my tests, replacing Hex2Int() with a 256 entry LUT slowed things down slightly
+					*dst = (byte)(Hex2Int(*src++) << 4 | Hex2Int(*src++));
+					count--;
+				}
 			}
 		}