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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 /utf8.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 'utf8.c')
-rw-r--r--utf8.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/utf8.c b/utf8.c
index 47a4204..2c27ce0 100644
--- a/utf8.c
+++ b/utf8.c
@@ -32,7 +32,7 @@ static int bisearch(ucs_char_t ucs, const struct interval *table, int max)
if (ucs < table[0].first || ucs > table[max].last)
return 0;
while (max >= min) {
- mid = (min + max) / 2;
+ mid = min + (max - min) / 2;
if (ucs > table[mid].last)
min = mid + 1;
else if (ucs < table[mid].first)