diff -r -u -F '^function' geshifilter/geshifilter.module geshifilter_mod/geshifilter.module
--- geshifilter/geshifilter.module	2007-09-30 10:02:34.000000000 -0500
+++ geshifilter_mod/geshifilter.module	2007-10-06 18:29:20.000000000 -0500
@@ -298,6 +298,9 @@ function geshifilter_filter($op, $delta 
     case 'description':
       return t('Enables syntax highlighting of inline/block source code using the GeSHi engine');
 
+    case 'prepare':
+      return _geshifilter_prepare($format, $text);
+
     case 'process':
       return _geshifilter_process($format, $text);
 
@@ -866,6 +869,44 @@ function _geshifilter_get_tags($format) 
 }
 
 /**
+ * geshifilter_filter callback for preparing input text.
+ */
+function _geshifilter_prepare($format, $text) {
+  // get the available tags
+  list($generic_code_tags, $language_tags, $tag_to_lang) = _geshifilter_get_tags($format);
+  $tags = array_merge($generic_code_tags, $language_tags);
+  $tags_string = implode('|', $tags);
+  
+  // Pattern for matching "<code>...</code>" like stuff
+  // Also matches "<code>...$"  where "$" refers to end of string, not end of
+  // line (because PCRE_MULTILINE (modifier 'm') is not enabled), so matching
+  // still works when teaser view trims inside the source code.
+  switch (_geshifilter_brackets($format)) {
+    case GESHIFILTER_BRACKETS_ANGLE:
+      $pattern = '#<('. $tags_string .')([^>]*)>(.*?)(</\1\s*>|$)#s';
+      $text = preg_replace_callback($pattern, '_geshifilter_prepare_callback', $text);
+      break;
+    case GESHIFILTER_BRACKETS_BOTH:
+      $pattern = '#[<\[]('. $tags_string .')([^>\]]*)[>\]](.*?)([<\[]/\1\s*[>\]]|$)#s';
+      $text = preg_replace_callback($pattern, '_geshifilter_prepare_callback', $text);
+      break;
+  }
+
+  return $text;
+}
+
+/**
+ * geshifilter_filter callback for preparing input text with GESHIFILTER_BRACKETS_ANGLE.
+ * We need to strip out < and > characters so that other filters don't get confused
+ * and think that portions of the text are HTML tags that are not allowed (and therefore
+ * removed).  We use the bytes 0xFE and 0xFF to replace < > during the filtering process.
+ * These bytes are not valid in UTF-8 data and thus least likely to cause problems.
+ */
+function _geshifilter_prepare_callback($match) {
+  return "\xFE". $match[1] . $match[2] ."\xFF". geshifilter_escape($match[3]) ."\xFE/". $match[1]. "\xFF";
+}
+
+/**
  * geshifilter_filter callback for processing input text.
  */
 function _geshifilter_process($format, $text) {
@@ -886,13 +927,13 @@ function _geshifilter_process($format, $
   // still works when teaser view trims inside the source code.
   switch (_geshifilter_brackets($format)) {
     case GESHIFILTER_BRACKETS_ANGLE:
-      $pattern = '#<('. $tags_string .')([^>]*)>(.*?)(</\1\s*>|$)#s';
+      $pattern = '#\xFE('. $tags_string .')([^\xFF]*)\xFF(.*?)(\xFE/\1\s*\xFF|$)#s';
       break;
     case GESHIFILTER_BRACKETS_SQUARE:
       $pattern = '#\[('. $tags_string .')([^\]]*)\](.*?)(\[/\1\s*\]|$)#s';
       break;
     case GESHIFILTER_BRACKETS_BOTH:
-      $pattern = '#[<\[]('. $tags_string .')([^>\]]*)[>\]](.*?)([<\[]/\1\s*[>\]]|$)#s';
+      $pattern = '#[\xFE\[]('. $tags_string .')([^\xFF\]]*)[\xFF\]](.*?)([\xFE\[]/\1\s*[\xFF\]]|$)#s';
       break;
   }
 
@@ -911,6 +952,9 @@ function _geshifilter_replace_callback($
   $tag_name = $match[1];
   $tag_attributes = $match[2];
   $source_code = $match[3];
+  
+   // Undo linebreak escaping
+  $source_code = str_replace('&#10;', "\n", $source_code);
 
   // get the possible tags and languages
   list($generic_code_tags, $language_tags, $tag_to_lang) = _geshifilter_get_tags($format);
@@ -1059,3 +1103,10 @@ function geshifilter_clear_available_lan
   drupal_set_message('Available languages cache cleared.');
   drupal_goto();
 }
+
+function geshifilter_escape($text) {
+  // Note, pay attention to odd preg_replace-with-/e behaviour on slashes
+  // Protect newlines from linebreak filter
+  // Copied from codefilter_escape() in codefilter.module
+  return str_replace(array("\r", "\n"), array('', '&#10;'), check_plain(str_replace('\"', '"', $text)));
+}
\ No newline at end of file