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 --- cache-tree.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'cache-tree.c') diff --git a/cache-tree.c b/cache-tree.c index 71d092ed51..d3f7401278 100644 --- a/cache-tree.c +++ b/cache-tree.c @@ -49,7 +49,7 @@ static int subtree_pos(struct cache_tree *it, const char *path, int pathlen) lo = 0; hi = it->subtree_nr; while (lo < hi) { - int mi = (lo + hi) / 2; + int mi = lo + (hi - lo) / 2; struct cache_tree_sub *mdl = down[mi]; int cmp = subtree_name_cmp(path, pathlen, mdl->name, mdl->namelen); -- cgit v1.2.3