packed object data:
If it is not DELTA, then deflated bytes (the size above
is the size before compression).
- If it is DELTA, then
+ If it is REF_DELTA, then
20-byte base object name SHA1 (the size above is the
size of the delta data that follows).
delta data, deflated.
+ If it is OFS_DELTA, then
+ n-byte offset (see below) interpreted as a negative
+ offset from the type-byte of the header of the
+ ofs-delta entry (the size above is the size of
+ the delta data that follows).
+ delta data, deflated.
+
+ offset encoding:
+ n bytes with MSB set in all but the last one.
+ The offset is then the number constructed by
+ concatenating the lower 7 bit of each byte, and
+ for n >= 2 adding 2^7 + 2^14 + ... + 2^(7*(n-1))
+ to the result.
+
= Version 2 pack-*.idx files support packs larger than 4 GiB, and