From 2feece847fb1a02f82d1f7ab13a84d1f24caf79a Mon Sep 17 00:00:00 2001
From: nattthebear <goyuken@gmail.com>
Date: Mon, 10 Aug 2020 10:59:23 -0400
Subject: [PATCH] I don't understand why we're clearing the rewind buffer, but
 if we want to do that, just do it, and don't deallocate + reallocate many
 megs of ram on every loadstate (#2282)

---
 src/BizHawk.Client.Common/rewind/IRewinder.cs | 2 ++
 src/BizHawk.Client.Common/rewind/Zwinder.cs   | 5 +++++
 src/BizHawk.Client.EmuHawk/MainForm.cs        | 9 ++-------
 3 files changed, 9 insertions(+), 7 deletions(-)

diff --git a/src/BizHawk.Client.Common/rewind/IRewinder.cs b/src/BizHawk.Client.Common/rewind/IRewinder.cs
index aa7e0b9fe9..6e88dd6d0e 100644
--- a/src/BizHawk.Client.Common/rewind/IRewinder.cs
+++ b/src/BizHawk.Client.Common/rewind/IRewinder.cs
@@ -19,5 +19,7 @@ namespace BizHawk.Client.Common
 
 		void Suspend();
 		void Resume();
+
+		void Clear();
 	}
 }
diff --git a/src/BizHawk.Client.Common/rewind/Zwinder.cs b/src/BizHawk.Client.Common/rewind/Zwinder.cs
index 94c4a2bef6..93d10a4f1d 100644
--- a/src/BizHawk.Client.Common/rewind/Zwinder.cs
+++ b/src/BizHawk.Client.Common/rewind/Zwinder.cs
@@ -85,5 +85,10 @@ namespace BizHawk.Client.Common
 		{
 			// this possess no resources to dispose of, but other IRewinder impls might
 		}
+
+		public void Clear()
+		{
+			_buffer.InvalidateEnd(0);
+		}
 	}
 }
diff --git a/src/BizHawk.Client.EmuHawk/MainForm.cs b/src/BizHawk.Client.EmuHawk/MainForm.cs
index 222a8a8d27..5699c791e4 100644
--- a/src/BizHawk.Client.EmuHawk/MainForm.cs
+++ b/src/BizHawk.Client.EmuHawk/MainForm.cs
@@ -887,17 +887,12 @@ namespace BizHawk.Client.EmuHawk
 		public IRewinder Rewinder { get; private set; }
 
 		public void CreateRewinder()
-		{
-			RecreateRewinder();
-			AddOnScreenMessage(Rewinder?.Active == true ? "Rewind started" : "Rewind disabled");
-		}
-
-		void RecreateRewinder()
 		{
 			Rewinder?.Dispose();
 			Rewinder = Emulator.HasSavestates() && Config.Rewind.Enabled
 				? new Zwinder(Emulator.AsStatable(), Config.Rewind)
 				: null;
+			AddOnScreenMessage(Rewinder?.Active == true ? "Rewind started" : "Rewind disabled");
 		}
 
 		private FirmwareManager FirmwareManager => GlobalWin.FirmwareManager;
@@ -3992,7 +3987,7 @@ namespace BizHawk.Client.EmuHawk
 				//so purge rewind history when loading a state while doing a movie
 				if (!IsRewindSlave && MovieSession.Movie.IsActive())
 				{
-					RecreateRewinder();
+					Rewinder?.Clear();
 				}
 
 				if (!suppressOSD)