From 19716b21a4255ecc7148b54ab2c78039c59f25bf Mon Sep 17 00:00:00 2001 From: Derrick Stolee Date: Sun, 8 Oct 2017 14:29:37 -0400 Subject: 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 Reviewed-by: Jeff King Signed-off-by: Junio C Hamano --- string-list.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'string-list.c') diff --git a/string-list.c b/string-list.c index 806b4c8723..a0cf0cfe88 100644 --- a/string-list.c +++ b/string-list.c @@ -16,7 +16,7 @@ static int get_entry_index(const struct string_list *list, const char *string, compare_strings_fn cmp = list->cmp ? list->cmp : strcmp; while (left + 1 < right) { - int middle = (left + right) / 2; + int middle = left + (right - left) / 2; int compare = cmp(string, list->items[middle].string); if (compare < 0) right = middle; -- cgit v1.2.3