diff --git a/SabreTools.Helper/Data/Enums.cs b/SabreTools.Helper/Data/Enums.cs
index 08966a83..44673e43 100644
--- a/SabreTools.Helper/Data/Enums.cs
+++ b/SabreTools.Helper/Data/Enums.cs
@@ -111,4 +111,37 @@
 		Internal,
 		External,
 	}
+
+	/// <summary>
+	/// Determines the header skip operation
+	/// </summary>
+	public enum HeaderSkipOperation
+	{
+		None = 0,
+		Bitswap,
+		Byteswap,
+		Wordswap,
+	}
+
+	/// <summary>
+	/// Determines the type of test to be done
+	/// </summary>
+	public enum HeaderSkipTest
+	{
+		Data = 0,
+		Or,
+		Xor,
+		And,
+		File,
+	}
+
+	/// <summary>
+	/// Determines the operator to be used in a file test
+	/// </summary>
+	public enum HeaderSkipTestFileOperator
+	{
+		Equal = 0,
+		Less,
+		Greater,
+	}
 }
diff --git a/SabreTools.Helper/Data/Structs.cs b/SabreTools.Helper/Data/Structs.cs
index 16a62d76..a60ca828 100644
--- a/SabreTools.Helper/Data/Structs.cs
+++ b/SabreTools.Helper/Data/Structs.cs
@@ -149,4 +149,29 @@ namespace SabreTools.Helper
 			};
 		}
 	}
+
+	/// <summary>
+	/// Intermediate struct for holding header skipper rule information
+	/// </summary>
+	public struct SkipperRule
+	{
+		long? StartOffset; // null is EOF
+		long? EndOffset; // null if EOF
+		HeaderSkipOperation Operation;
+		List<SkipperTest> Tests;
+	}
+
+	/// <summary>
+	/// Intermediate struct for holding header test information
+	/// </summary>
+	public struct SkipperTest
+	{
+		HeaderSkipTest Type;
+		long? Offset; // null is EOF
+		byte[] Value;
+		bool Result;
+		byte[] Mask;
+		long? Size; // null is PO2, "power of 2" filesize
+		HeaderSkipTestFileOperator Operator;
+	}
 }