vb.org Archive - Autolinker and PCRE problem

I'm currently building a much needed Autolinker for vBulletin 4 (much like GAL) for release on vbulletin.org, and have the following issues with PCRE and replacing contents outside HTML tags:

Words with accents are not recognized as full words, thus a replacement for 'pi?' with 'x' results in 'xx' for 'pi?pi?'. But at most I can live without it.
Rules are not considering the tail of a string, so I must add a character ad the end, and remove later (and this, too, is a minor concern)

However, before realeasing a hack instead proper code, I would like to ask a PCRE professional for help on this problem. Here below is the code ready to paste into a php file:

PHP Code:


		
			
<?php
function pcre_cb($matches)
{
    return 'x';
}

$subject = 'pi? o pi?pi? o meno 1 <a href="abc.it">pi? o pi?pi? o meno 2</a> pi? o pi?pi? o meno 3 <a href="abc.it">pi? o pi?pi? o meno 4</a> pi? o pi?pi? o meno 5';
$pattern = '#\\b(pi?|abc\\.it)(?![^<]*>*(</|$))#im';
$text = preg_replace_callback($pattern, 'pcre_cb', $subject . '<');

echo nl2br(htmlspecialchars($text));
die;

Result:

Code:

x o xx o meno 1 <a href="abc.it">pi? o pi?pi? o meno 2</a> x o xx o meno 3 <a href="abc.it">pi? o pi?pi? o meno 4</a> x o xx o meno 5<

Wanted:

Code:

x o pi?pi? o meno 1 <a href="abc.it">pi? o pi?pi? o meno 2</a> x o pi?pi? o meno 3 <a href="abc.it">pi? o pi?pi? o meno 4</a> x o pi?pi? o meno 5

X vBulletin 3.8.12 by vBS Debug Information
Template Usage: (1)ad_footer_end (1)ad_footer_start (1)ad_header_end (1)ad_header_logo (1)ad_navbar_below (2)bbcode_code_printable (1)bbcode_php_printable (1)footer (1)gobutton (1)header (1)headinclude (6)option (1)post_thanks_navbar_search (1)printthread (1)printthreadbit (1)spacer_close (1)spacer_open Phrase Groups Available: global postbit showthread	Included Files: ./printthread.php ./global.php ./includes/init.php ./includes/class_core.php ./includes/config.php ./includes/functions.php ./includes/class_hook.php ./includes/modsystem_functions.php ./includes/class_bbcode_alt.php ./includes/class_bbcode.php ./includes/functions_bigthree.php Hooks Called: init_startup init_startup_session_setup_start init_startup_session_setup_complete cache_permissions fetch_threadinfo_query fetch_threadinfo fetch_foruminfo style_fetch cache_templates global_start parse_templates global_setup_complete printthread_start bbcode_fetch_tags bbcode_create bbcode_parse_start bbcode_parse_complete_precache bbcode_parse_complete printthread_post printthread_complete
Messages:

X vBulletin 3.8.12 by vBS Debug Information

Page Generation 0.01286 seconds
Memory Usage 1,715KB
Queries Executed 10 (?)

More Information

Template Usage:

(1)ad_footer_end
(1)ad_footer_start
(1)ad_header_end
(1)ad_header_logo
(1)ad_navbar_below
(2)bbcode_code_printable
(1)bbcode_php_printable
(1)footer
(1)gobutton
(1)header
(1)headinclude
(6)option
(1)post_thanks_navbar_search
(1)printthread
(1)printthreadbit
(1)spacer_close
(1)spacer_open

Phrase Groups Available:

global
postbit
showthread

Included Files:

./printthread.php
./global.php
./includes/init.php
./includes/class_core.php
./includes/config.php
./includes/functions.php
./includes/class_hook.php
./includes/modsystem_functions.php
./includes/class_bbcode_alt.php
./includes/class_bbcode.php
./includes/functions_bigthree.php

Hooks Called:

init_startup
init_startup_session_setup_start
init_startup_session_setup_complete
cache_permissions
fetch_threadinfo_query
fetch_threadinfo
fetch_foruminfo
style_fetch
cache_templates
global_start
parse_templates
global_setup_complete
printthread_start
bbcode_fetch_tags
bbcode_create
bbcode_parse_start
bbcode_parse_complete_precache
bbcode_parse_complete
printthread_post
printthread_complete

Messages:

X vBulletin 3.8.12 by vBS Debug Information
Page Generation 0.01286 seconds Memory Usage 1,715KB Queries Executed 10 (?)
More Information
Template Usage: (1)ad_footer_end (1)ad_footer_start (1)ad_header_end (1)ad_header_logo (1)ad_navbar_below (2)bbcode_code_printable (1)bbcode_php_printable (1)footer (1)gobutton (1)header (1)headinclude (6)option (1)post_thanks_navbar_search (1)printthread (1)printthreadbit (1)spacer_close (1)spacer_open Phrase Groups Available: global postbit showthread	Included Files: ./printthread.php ./global.php ./includes/init.php ./includes/class_core.php ./includes/config.php ./includes/functions.php ./includes/class_hook.php ./includes/modsystem_functions.php ./includes/class_bbcode_alt.php ./includes/class_bbcode.php ./includes/functions_bigthree.php Hooks Called: init_startup init_startup_session_setup_start init_startup_session_setup_complete cache_permissions fetch_threadinfo_query fetch_threadinfo fetch_foruminfo style_fetch cache_templates global_start parse_templates global_setup_complete printthread_start bbcode_fetch_tags bbcode_create bbcode_parse_start bbcode_parse_complete_precache bbcode_parse_complete printthread_post printthread_complete
Messages: