diff options
author | Derrick Stolee <dstolee@microsoft.com> | 2017-10-08 14:29:37 -0400 |
---|---|---|
committer | Junio C Hamano <gitster@pobox.com> | 2017-10-10 08:57:24 +0900 |
commit | 19716b21a4255ecc7148b54ab2c78039c59f25bf (patch) | |
tree | 5f1cecbffc543c64e7c4c4f371d204424e1ce1bb /builtin/pack-objects.c | |
parent | 217f2767cbcb562872437eed4dec62e00846d90c (diff) | |
download | git-ds/avoid-overflow-in-midpoint-computation.tar.gz |
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>
Diffstat (limited to 'builtin/pack-objects.c')
-rw-r--r-- | builtin/pack-objects.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/builtin/pack-objects.c b/builtin/pack-objects.c index 5ee2c48ffb..6e77dfd444 100644 --- a/builtin/pack-objects.c +++ b/builtin/pack-objects.c @@ -1277,7 +1277,7 @@ static int done_pbase_path_pos(unsigned hash) int lo = 0; int hi = done_pbase_paths_num; while (lo < hi) { - int mi = (hi + lo) / 2; + int mi = lo + (hi - lo) / 2; if (done_pbase_paths[mi] == hash) return mi; if (done_pbase_paths[mi] < hash) |