[PHP-DEV] [PATCH] random_int: Fix power of two check.

[Lauri Kenttä]

(x & ~x) is always 0.
((x & (~x + 1)) != x) works.
((x & (x - 1)) != 0) works too.
---
 ext/standard/random.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/ext/standard/random.c b/ext/standard/random.c
index 12c2503..4a1adbf 100644
--- a/ext/standard/random.c
+++ b/ext/standard/random.c
@@ -182,7 +182,7 @@ PHP_FUNCTION(random_int)
        umax++;
 
        /* Powers of two are not biased */
-       if ((umax & ~umax) != umax) {
+       if ((umax & (umax - 1)) != 0) {
                /* Ceiling under which ZEND_LONG_MAX % max == 0 */
                zend_ulong limit = ZEND_ULONG_MAX - (ZEND_ULONG_MAX % umax) - 1;
        
-- 
2.4.0


-- 
PHP Internals - PHP Runtime Development Mailing List
To unsubscribe, visit: http://www.php.net/unsub.php