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authorDerrick Stolee <dstolee@microsoft.com>2017-10-08 18:29:37 (GMT)
committerJunio C Hamano <gitster@pobox.com>2017-10-09 23:57:24 (GMT)
commit19716b21a4255ecc7148b54ab2c78039c59f25bf (patch)
tree5f1cecbffc543c64e7c4c4f371d204424e1ce1bb /sha1_name.c
parent217f2767cbcb562872437eed4dec62e00846d90c (diff)
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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 'sha1_name.c')
-rw-r--r--sha1_name.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/sha1_name.c b/sha1_name.c
index 134ac97..c7c5ab3 100644
--- a/sha1_name.c
+++ b/sha1_name.c
@@ -157,7 +157,7 @@ static void unique_in_pack(struct packed_git *p,
num = p->num_objects;
last = num;
while (first < last) {
- uint32_t mid = (first + last) / 2;
+ uint32_t mid = first + (last - first) / 2;
const unsigned char *current;
int cmp;