BUG/MINOR: sample: Fix wrong overflow detection in add/sub conveters

When "add" or "sub" conveters are used, an overflow detection is performed.
When 2 negative integers are added (or a positive integer is substracted to
a positive one), we take care to not exceed the low limit (LLONG_MIN) and
when 2 positive integers are added, we take care to not exceed the high
limit (LLONG_MAX).

However, because of a missing 'else' statement, if there is no overflow in
the first case, we fall back on the second check (the one for positive adds)
and LLONG_MAX is returned. It means that most of time, when 2 negative
integers are added (or a positive integer is substracted to a negative one),
LLONG_MAX is returned.

This patch should solve the issue #2216. It must be backported to all stable
versions.

diff --git a/src/sample.c b/src/sample.c
index 097f647b3c5fbbe498187d4254b58e3847e63c57..34c18a6b39abd0be94437efd8c50eefcd31828d5 100644 (file)
--- a/src/sample.c
+++ b/src/sample.c
@@ -2990,12 +2990,12 @@ static inline long long int arith_add(long long int a, long long int b)
         * +------+----------+----------+
         */
        if ((a ^ b) >= 0) {
-               /* signs are different. */
+               /* signs are same. */
                if (a < 0) {
                        if (LLONG_MIN - a > b)
                                return LLONG_MIN;
                }
-               if (LLONG_MAX - a < b)
+               else if (LLONG_MAX - a < b)
                        return LLONG_MAX;
        }
        return a + b;