pack-objects: document --delta-base-offset option

Signed-off-by: Junio C Hamano <junkio@cox.net>

diff --git a/Documentation/git-pack-objects.txt b/Documentation/git-pack-objects.txt
index d4661dd..5788709 100644 (file)
--- a/Documentation/git-pack-objects.txt
+++ b/Documentation/git-pack-objects.txt
@@ -9,7 +9,7 @@ git-pack-objects - Create a packed archive of objects
 SYNOPSIS
 --------
 [verse]
-'git-pack-objects' [-q] [--no-reuse-delta] [--non-empty]
+'git-pack-objects' [-q] [--no-reuse-delta] [--delta-base-offset] [--non-empty]
        [--local] [--incremental] [--window=N] [--depth=N]
        [--revs [--unpacked | --all]*] [--stdout | base-name] < object-list
 
@@ -110,6 +110,17 @@ base-name::
        This flag tells the command not to reuse existing deltas
        but compute them from scratch.
 
+--delta-base-offset::
+       A packed archive can express base object of a delta as
+       either 20-byte object name or as an offset in the
+       stream, but older version of git does not understand the
+       latter.  By default, git-pack-objects only uses the
+       former format for better compatibility.  This option
+       allows the command to use the latter format for
+       compactness.  Depending on the average delta chain
+       length, this option typically shrinks the resulting
+       packfile by 3-5 per-cent.
+
 
 Author
 ------

diff --git a/builtin-pack-objects.c b/builtin-pack-objects.c
index ee5f031..41e1e74 100644 (file)
--- a/builtin-pack-objects.c
+++ b/builtin-pack-objects.c
@@ -15,7 +15,7 @@
 #include <sys/time.h>
 #include <signal.h>
 
-static const char pack_usage[] = "git-pack-objects [-q] [--no-reuse-delta] [--non-empty] [--local] [--incremental] [--window=N] [--depth=N] [--revs [--unpacked | --all]*] [--stdout | base-name] <ref-list | <object-list]";
+static const char pack_usage[] = "git-pack-objects [-q] [--no-reuse-delta] [--delta-base-offset] [--non-empty] [--local] [--incremental] [--window=N] [--depth=N] [--revs [--unpacked | --all]*] [--stdout | base-name] <ref-list | <object-list]";
 
 struct object_entry {
        unsigned char sha1[20];