From 61fb7888001d007563627c3940b2749c9d43959b Mon Sep 17 00:00:00 2001
From: Matt Nadareski <mnadareski@outlook.com>
Date: Wed, 21 Feb 2018 10:54:43 -0800
Subject: [PATCH] [CHDFile] Ensure CHD is not blocking DFD

---
 SabreTools.Library/FileTypes/CHDFile.cs | 21 ++++++++++++++-------
 1 file changed, 14 insertions(+), 7 deletions(-)

diff --git a/SabreTools.Library/FileTypes/CHDFile.cs b/SabreTools.Library/FileTypes/CHDFile.cs
index 8c543c9f..d78b85e8 100644
--- a/SabreTools.Library/FileTypes/CHDFile.cs
+++ b/SabreTools.Library/FileTypes/CHDFile.cs
@@ -173,14 +173,21 @@ namespace SabreTools.Library.FileTypes
 
 			_headerVersion = ValidateHeaderVersion();
 
-			byte[] hash = GetHashFromHeader();
-			if (hash.Length == Constants.MD5Length)
+			if (_headerVersion != null)
 			{
-				_md5 = hash;
-			}
-			else if (hash.Length == Constants.SHA1Length)
-			{
-				_sha1 = hash;
+				byte[] hash = GetHashFromHeader();
+
+				if (hash != null)
+				{
+					if (hash.Length == Constants.MD5Length)
+					{
+						_md5 = hash;
+					}
+					else if (hash.Length == Constants.SHA1Length)
+					{
+						_sha1 = hash;
+					}
+				}
 			}
 		}