From f473db56c308afce62914386620c049a9b9a5587 Mon Sep 17 00:00:00 2001
From: YoshiRulz <OSSYoshiRulz@gmail.com>
Date: Sun, 5 Feb 2023 20:48:48 +1000
Subject: [PATCH] Fix NaN propagation in RewindConfig

---
 .../config/RewindConfig.cs                    | 32 ++++++++++---------
 1 file changed, 17 insertions(+), 15 deletions(-)

diff --git a/src/BizHawk.Client.EmuHawk/config/RewindConfig.cs b/src/BizHawk.Client.EmuHawk/config/RewindConfig.cs
index 1b6a75b9d7..b8764c9868 100755
--- a/src/BizHawk.Client.EmuHawk/config/RewindConfig.cs
+++ b/src/BizHawk.Client.EmuHawk/config/RewindConfig.cs
@@ -8,7 +8,7 @@ namespace BizHawk.Client.EmuHawk
 {
 	public partial class RewindConfig : Form
 	{
-		private double _avgStateSize;
+		private ulong _avgStateSize;
 
 		private readonly Config _config;
 
@@ -34,15 +34,17 @@ namespace BizHawk.Client.EmuHawk
 			var rewinder = _getRewinder();
 			if (rewinder?.Active == true)
 			{
-				FullnessLabel.Text = $"{rewinder.FullnessRatio:P2}";
-				RewindFramesUsedLabel.Text = rewinder.Count.ToString();
-				_avgStateSize = rewinder.Size * rewinder.FullnessRatio / rewinder.Count;
+				var fullnessRatio = rewinder.FullnessRatio;
+				FullnessLabel.Text = $"{fullnessRatio:P2}";
+				var stateCount = rewinder.Count;
+				RewindFramesUsedLabel.Text = stateCount.ToString();
+				_avgStateSize = stateCount is 0 ? 0UL : (ulong) Math.Round(rewinder.Size * fullnessRatio / stateCount);
 			}
 			else
 			{
 				FullnessLabel.Text = "N/A";
 				RewindFramesUsedLabel.Text = "N/A";
-				_avgStateSize = _statableCore.CloneSavestate().Length;
+				_avgStateSize = (ulong) _statableCore.CloneSavestate().Length;
 			}
 
 			RewindEnabledBox.Checked = _config.Rewind.Enabled;
@@ -77,7 +79,7 @@ namespace BizHawk.Client.EmuHawk
 				ScreenshotInStatesCheckbox.Checked;
 		}
 
-		private string FormatKB(double n)
+		private string FormatKB(ulong n)
 		{
 			double num = n / 1024.0;
 
@@ -139,16 +141,16 @@ namespace BizHawk.Client.EmuHawk
 
 		private void CalculateEstimates()
 		{
-			var bufferSize = 1L << (int) BufferSizeUpDown.Value;
-			labelEx1.Text = bufferSize.ToString();
-			bufferSize *= 1024 * 1024;
-			var estFrames = bufferSize / _avgStateSize;
-
-			double estTotalFrames = estFrames;
-			double minutes = estTotalFrames / 60 / 60;
-
+			double estFrames = 0.0;
+			if (_avgStateSize is not 0UL)
+			{
+				var bufferSize = 1L << (int) BufferSizeUpDown.Value;
+				labelEx1.Text = bufferSize.ToString();
+				bufferSize *= 1024 * 1024;
+				estFrames = bufferSize / (double) _avgStateSize;
+			}
 			ApproxFramesLabel.Text = $"{estFrames:n0} frames";
-			EstTimeLabel.Text = $"{minutes:n} minutes";
+			EstTimeLabel.Text = $"{estFrames / 3600.0:n} minutes";
 		}
 
 		private void BufferSizeUpDown_ValueChanged(object sender, EventArgs e)