Better equality code

SabreTools.Library/DatItems/DatItem.cs

@@ -1106,6 +1106,26 @@ namespace SabreTools.Library.DatItems
 
         #region Sorting and Merging
 
+        /// <summary>
+        /// Determine if two hashes are equal for the purposes of merging
+        /// </summary>
+        /// <param name="firstHash">First hash to compare</param>
+        /// <param name="secondHash">Second hash to compare</param>
+        /// <returns>True if either is empty OR the hashes exactly match, false otherwise</returns>
+        public static bool ConditionalHashEquals(byte[] firstHash, byte[] secondHash)
+        {
+            // If either hash is empty, we say they're equal for merging
+            if (firstHash.IsNullOrEmpty() || secondHash.IsNullOrEmpty())
+                return true;
+
+            // If they're different sizes, they can't match
+            if (firstHash.Length != secondHash.Length)
+                return false;
+
+            // Otherwise, they need to match exactly
+            return Enumerable.SequenceEqual(firstHash, secondHash);
+        }
+
         /// <summary>
         /// Merge an arbitrary set of ROMs based on the supplied information
         /// </summary>