今日头条

preg_match limit

发布日期：2008-04-25
Description:
------------
The following preg_replace breaks when the string is => 24999
characters. Works perfectly fine with 24998 characters and worked fine
with any strings in PHP 5.1.5.

Reproduce code:
---------------
$string = str_repeat('a', 100000);
echo
preg_replace('#(^.*|.*)(\[(php|html|noparse)\].*\[/\\3])(.*|.*$)#siUe',
'', $string);
?>

Expected result:
----------------
100.000 times 'a'

Actual result:
--------------
nothing

[6 Nov 2006 8:48pm UTC] ludvig dot ericson at gmail dot com

This is because of limits intentionally set, see the ini setting
pcre.backtrack_limit.

[6 Nov 2006 8:50pm UTC] spam at dragy dot de

pcre.backtrack_limit=-1 in php.ini

[14 Nov 2006 7:07pm UTC] tony2001@php.net

I was wrong, there are pcre.backtrack_limit and pcre.recursion_limit
directives, which might be used to control this functionality.

http://bugs.php.net/bug.php?id=39405