From: Andre Noll <maan@tuebingen.mpg.de>
Date: Tue, 15 Mar 2016 19:41:37 +0000 (+0100)
Subject: mood.c: Avoid integer overflow.
X-Git-Tag: v0.5.6~45^2~5
X-Git-Url: http://git.tuebingen.mpg.de/?p=paraslash.git;a=commitdiff_plain;h=58566e1535a0c47ce59570598885ccabc75891bf

mood.c: Avoid integer overflow.

The quadratic deviation qd can be very large, causing the
multiplication n * qd to overflow. The new code avoids the
multiplication at the cost of two calls to int_sqrt() instead of one.
---

diff --git a/mood.c b/mood.c
index 8e6a7665..e026c960 100644
--- a/mood.c
+++ b/mood.c
@@ -472,7 +472,7 @@ static int64_t normalized_value(int64_t x, int64_t n, int64_t sum, int64_t qd)
 {
 	if (!n || !qd)
 		return 0;
-	return 100 * (n * x - sum) / (int64_t)int_sqrt(n * qd);
+	return 100 * (n * x - sum) / (int64_t)int_sqrt(n) / (int64_t)int_sqrt(qd);
 }
 
 static long compute_num_played_score(struct afs_info *afsi)