diff options
author | Derrick Stolee <dstolee@microsoft.com> | 2017-10-08 21:29:37 +0300 |
---|---|---|
committer | Junio C Hamano <gitster@pobox.com> | 2017-10-10 02:57:24 +0300 |
commit | 19716b21a4255ecc7148b54ab2c78039c59f25bf (patch) | |
tree | 5f1cecbffc543c64e7c4c4f371d204424e1ce1bb /builtin/index-pack.c | |
parent | 217f2767cbcb562872437eed4dec62e00846d90c (diff) |
cleanup: fix possible overflow errors in binary search
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/index-pack.c')
-rw-r--r-- | builtin/index-pack.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/builtin/index-pack.c b/builtin/index-pack.c index f2be145e12..8ec459f522 100644 --- a/builtin/index-pack.c +++ b/builtin/index-pack.c @@ -633,7 +633,7 @@ static int find_ofs_delta(const off_t offset, enum object_type type) int first = 0, last = nr_ofs_deltas; while (first < last) { - int next = (first + last) / 2; + int next = first + (last - first) / 2; struct ofs_delta_entry *delta = &ofs_deltas[next]; int cmp; @@ -687,7 +687,7 @@ static int find_ref_delta(const unsigned char *sha1, enum object_type type) int first = 0, last = nr_ref_deltas; while (first < last) { - int next = (first + last) / 2; + int next = first + (last - first) / 2; struct ref_delta_entry *delta = &ref_deltas[next]; int cmp; |