From: Lauri Kenttä <lauri.kentta@gmail.com>
Date: Sun, 10 May 2015 10:40:29 +0000 (+0300)
Subject: random_int: Fix power of two check.
X-Git-Tag: PRE_PHP7_NSAPI_REMOVAL~53
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=cf7e5357a46afe1dca978f4887bbd83a7507ce69;p=php

random_int: Fix power of two check.

(x & ~x) is always 0.
((x & (~x + 1)) != x) works.
((x & (x - 1)) != 0) works too.
---

diff --git a/ext/standard/random.c b/ext/standard/random.c
index 12c25031d8..4a1adbfb02 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;