Hi,
when pcre.backtrack_limit is reached with preg_replace() the subject
string gets truncated to a string of length zero.
Here is a simple example (yes I know you shouldn't write a regexp like
that but it is simplified from a real pattern a coworker used).
,----[ PHP5.3 ]
| m58s03:~# php -r '$s = str_repeat("a", 9999);echo
strlen(preg_replace("/a(.*?)b/", "\$1", $s)),"\n";'
| 9999
| m58s03:~# php -r 'ini_set("pcre.backtrack_limit",10);$s = str_repeat("a",
9999);echo strlen(preg_replace("/a(.*?)b/", "\$1", $s)),"\n";'
| 0
| m58s03:~# php -r '$s = str_repeat("a", 99998);echo
strlen(preg_replace("/a(.*?)b/", "\$1", $s)),"\n";'
| 0
| m58s03:~# php -i|grep pcre
| pcre
| pcre.backtrack_limit => 100000 => 100000
| pcre.recursion_limit => 100000 => 100000
| m58s03:~# php -v
| PHP 5.3.0-dev (cli) (built: Jan 20 2008 20:59:20)
| Copyright (c) 1997-2008 The PHP Group
| Zend Engine v2.3.0, Copyright (c) 1998-2008 Zend Technologies
`----
The same happens with PHP 5.2.5. The pcre lib is the one shipped with
PHP.
KP
--
PHP Internals - PHP Runtime Development Mailing List
To unsubscribe, visit: http://www.php.net/unsub.php
