cleanup: fix possible overflow errors in binary searchds/avoid-overflow-in-midpoint-computation

A common mistake when writing binary search is to allow possible
integer overflow by using the simple average:

	mid = (min + max) / 2;

Instead, use the overflow-safe version:

	mid = min + (max - min) / 2;

This translation is safe since the operation occurs inside a loop
conditioned on "min < max". The included changes were found using
the following git grep:

	git grep '/ *2;' '*.c'

Making this cleanup will prevent future review friction when a new
binary search is contructed based on existing code.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Reviewed-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/packfile.c b/packfile.c
index eab7542487..4a5fe7ab18 100644
--- a/packfile.c
+++ b/packfile.c
@@ -1743,7 +1743,7 @@ off_t find_pack_entry_one(const unsigned char *sha1,
 		       sha1[0], sha1[1], sha1[2], lo, hi, p->num_objects);
 
 	while (lo < hi) {
-		unsigned mi = (lo + hi) / 2;
+		unsigned mi = lo + (hi - lo) / 2;
 		int cmp = hashcmp(index + mi * stride, sha1);
 
 		if (debug_lookup)