diff-delta.c: allow delta with empty blob.

Delta computation with an empty blob used to punt and returned NULL.
This commit allows creation with empty blob; all combination of
empty->empty, empty->something, and something->empty are allowed.

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

1 files changed, 2 insertions, 2 deletions

diff --git a/delta.h b/delta.h
index 31d1820f80..c6a476353f 100644
--- a/delta.h
+++ b/delta.h
@@ -9,8 +9,8 @@ extern void *patch_delta(void *src_buf, unsigned long src_size,
 			 void *delta_buf, unsigned long delta_size,
 			 unsigned long *dst_size);
 
-/* the smallest possible delta size is 4 bytes */
-#define DELTA_SIZE_MIN	4
+/* the smallest possible delta size is 2 bytes (empty to empty) */
+#define DELTA_SIZE_MIN	2
 
 /*
  * This must be called twice on the delta data buffer, first to get the