[PATCH] random_int: Fix power of two check.
| From: | Lauri Kenttä | Date: | Sun, 10 May 2015 10:40:29 +0000 |
| Subject: | [PATCH] random_int: Fix power of two check. | ||
| Groups: | php.internals | ||
| Request: | Send a blank email to internals+get-86148@lists.php.net to get a copy of this message | ||
(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