multi-pack-index: load into memory

Create a new multi_pack_index struct for loading multi-pack-indexes into
memory. Create a test-tool builtin for reading basic information about
that multi-pack-index to verify the correct data is written.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 18 insertions, 0 deletions

diff --git a/midx.h b/midx.h
index dbdbe9f873..0e05051bca 100644
--- a/midx.h
+++ b/midx.h
@@ -1,6 +1,24 @@
 #ifndef __MIDX_H__
 #define __MIDX_H__
 
+struct multi_pack_index {
+	int fd;
+
+	const unsigned char *data;
+	size_t data_len;
+
+	uint32_t signature;
+	unsigned char version;
+	unsigned char hash_len;
+	unsigned char num_chunks;
+	uint32_t num_packs;
+	uint32_t num_objects;
+
+	char object_dir[FLEX_ARRAY];
+};
+
+struct multi_pack_index *load_multi_pack_index(const char *object_dir);
+
 int write_midx_file(const char *object_dir);
 
 #endif