From 73d68a033dc3365f069be19bd14874491c654e2e Mon Sep 17 00:00:00 2001
From: stronk7 <stronk7>
Date: Fri, 2 Sep 2005 00:01:22 +0000
Subject: [PATCH] Strip control chars from being sent to the XML file. Only
 tab, newline and return are allowed in XML 1.0. This feature is controlled by
 $CFG->backup_strip_controlchars.

Please, test it!
---
 backup/backuplib.php | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/backup/backuplib.php b/backup/backuplib.php
index 62fccd482b8..d188c45a8d2 100644
--- a/backup/backuplib.php
+++ b/backup/backuplib.php
@@ -435,8 +435,20 @@
     
     //Return the start tag, the contents and the end tag
     function full_tag($tag,$level=0,$endline=true,$content,$to_utf=true) {
+
+        global $CFG;
+
         //Here we encode absolute links
         $content = backup_encode_absolute_links($content);
+
+        //If enabled, we strip all the control chars from the text but tabs, newlines and returns
+        //because they are forbiden in XML 1.0 specs. The expression below seems to be
+        //UTF-8 safe too because it simply ignores the rest of characters.
+        if (!empty($CFG->backup_strip_controlchars)) {
+            $content = preg_replace("/(?(?=[[:cntrl:]])[^\n\r\t])/is","",$content);
+        }
+
+        //Start to build the tag
         $st = start_tag($tag,$level,$endline);
         $co="";
         if ($to_utf) {