1 files changed, 13 insertions, 6 deletions
diff --git a/pack.h b/pack.h
index 08e120dca6..83ac3218bd 100644
--- a/pack.h
+++ b/pack.h
@@ -1,19 +1,26 @@
 #ifndef PACK_H
 #define PACK_H
 
+/*
+ * The packed object type is stored in 3 bits.
+ * The type value 0 is a reserved prefix if ever there is more than 7
+ * object types, or any future format extensions.
+ */
 enum object_type {
-	OBJ_NONE,
-	OBJ_COMMIT,
-	OBJ_TREE,
-	OBJ_BLOB,
-	OBJ_TAG,
-	OBJ_DELTA,
+	OBJ_EXT = 0,
+	OBJ_COMMIT = 1,
+	OBJ_TREE = 2,
+	OBJ_BLOB = 3,
+	OBJ_TAG = 4,
+	/* 5/6 for future expansion */
+	OBJ_DELTA = 7,
 };
 
 /*
  * Packed object header
  */
 #define PACK_SIGNATURE 0x5041434b	/* "PACK" */
+#define PACK_VERSION 2
 struct pack_header {
 	unsigned int hdr_signature;
 	unsigned int hdr_version;