pack-format.txt: more details on pack file format

The current document mentions OBJ_* constants without their actual
values. A git developer would know these are from cache.h but that's
not very friendly to a person who wants to read this file to implement
a pack file parser.

Similarly, the deltified representation is not documented at all (the
"document" is basically patch-delta.c). Translate that C code to
English with a bit more about what ofs-delta and ref-delta mean.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 5 insertions, 0 deletions

diff --git a/cache.h b/cache.h
index a61b2d3f0d..a3f82faf0e 100644
--- a/cache.h
+++ b/cache.h
@@ -373,6 +373,11 @@ extern void free_name_hash(struct index_state *istate);
 #define read_blob_data_from_cache(path, sz) read_blob_data_from_index(&the_index, (path), (sz))
 #endif
 
+/*
+ * Values in this enum (except those outside the 3 bit range) are part
+ * of pack file format. See Documentation/technical/pack-format.txt
+ * for more information.
+ */
 enum object_type {
 	OBJ_BAD = -1,
 	OBJ_NONE = 0,