1 files changed, 19 insertions, 0 deletions
diff --git a/midx.h b/midx.h
index b374a7afaf..dc477dff44 100644
--- a/midx.h
+++ b/midx.h
@@ -8,6 +8,25 @@ struct pack_entry;
 struct repository;
 struct bitmapped_pack;
 
+#define MIDX_SIGNATURE 0x4d494458 /* "MIDX" */
+#define MIDX_VERSION 1
+#define MIDX_BYTE_FILE_VERSION 4
+#define MIDX_BYTE_HASH_VERSION 5
+#define MIDX_BYTE_NUM_CHUNKS 6
+#define MIDX_BYTE_NUM_PACKS 8
+#define MIDX_HEADER_SIZE 12
+
+#define MIDX_CHUNK_ALIGNMENT 4
+#define MIDX_CHUNKID_PACKNAMES 0x504e414d /* "PNAM" */
+#define MIDX_CHUNKID_BITMAPPEDPACKS 0x42544d50 /* "BTMP" */
+#define MIDX_CHUNKID_OIDFANOUT 0x4f494446 /* "OIDF" */
+#define MIDX_CHUNKID_OIDLOOKUP 0x4f49444c /* "OIDL" */
+#define MIDX_CHUNKID_OBJECTOFFSETS 0x4f4f4646 /* "OOFF" */
+#define MIDX_CHUNKID_LARGEOFFSETS 0x4c4f4646 /* "LOFF" */
+#define MIDX_CHUNKID_REVINDEX 0x52494458 /* "RIDX" */
+#define MIDX_CHUNK_OFFSET_WIDTH (2 * sizeof(uint32_t))
+#define MIDX_LARGE_OFFSET_NEEDED 0x80000000
+
 #define GIT_TEST_MULTI_PACK_INDEX "GIT_TEST_MULTI_PACK_INDEX"
 #define GIT_TEST_MULTI_PACK_INDEX_WRITE_BITMAP \
 	"GIT_TEST_MULTI_PACK_INDEX_WRITE_BITMAP"