Update the index format documentation to mention the v4 format.
* nd/doc-index-format:
update-index: list supported idx versions and their features
read-cache.c: use INDEX_FORMAT_{LB,UB} in verify_hdr()
index-format.txt: mention of v4 is missing in some places
--index-version <n>::
Write the resulting index out in the named on-disk format version.
- The current default version is 2.
+ Supported versions are 2, 3 and 4. The current default version is 2
+ or 3, depending on whether extra features are used, such as
+ `git add -N`.
++
+Version 4 performs a simple pathname compression that reduces index
+size by 30%-50% on large repositories, which results in faster load
+time. Version 4 is relatively young (first released in in 1.8.0 in
+October 2012). Other Git implementations such as JGit and libgit2
+may not support it yet.
-z::
Only meaningful with `--stdin` or `--index-info`; paths are
The signature is { 'D', 'I', 'R', 'C' } (stands for "dircache")
4-byte version number:
- The current supported versions are 2 and 3.
+ The current supported versions are 2, 3 and 4.
32-bit number of index entries.
12-bit name length if the length is less than 0xFFF; otherwise 0xFFF
is stored in this field.
- (Version 3) A 16-bit field, only applicable if the "extended flag"
- above is 1, split into (high to low bits).
+ (Version 3 or later) A 16-bit field, only applicable if the
+ "extended flag" above is 1, split into (high to low bits).
1-bit reserved for future
if (hdr->hdr_signature != htonl(CACHE_SIGNATURE))
return error("bad signature");
hdr_version = ntohl(hdr->hdr_version);
- if (hdr_version < 2 || 4 < hdr_version)
+ if (hdr_version < INDEX_FORMAT_LB || INDEX_FORMAT_UB < hdr_version)
return error("bad index version %d", hdr_version);
git_SHA1_Init(&c);
git_SHA1_Update(&c, hdr, size - 20);