LinuxQuestions.org - Speeding up the script, or the SQL Query?

Ok first of all. I'll explain what I'm trying to achieve.

This is a little script that will take a post similar to this one, and from a list of cards from a table in the database, compare it and if the words match, then it will add a [card]MATCHED WORD[/card] ([card] tags around the matched word).

Code:

  

if ( !empty($selected_text) ) 

      { 

              $sql = "SELECT card_name 

                      FROM " . CARDS_TABLE . " 

                      ORDER BY length(card_name) DESC"; 



              if ( !($result = $db->sql_query($sql)) ) 

              { 

                      message_die(GENERAL_ERROR, 'Could not obtain search results', '', __LINE__, __FILE__, $sql); 

              } 



              if ( $row = $db->sql_fetchrow($result) ) 

              { 

                      $i = 0; 

                      do 

                      { 

                              $text_arr[$i] = $row['card_name']; 

                              $selected_text = eregi_replace($text_arr[$i],'[card]'.$i.'[/card]',$selected_text); 

                              $i++; 

                      } 

                      while ( $row = $db->sql_fetchrow($result) ); 



                      for($j = 0; $j < $i; $j++) 

                      { 

                              $selected_text = str_replace('[card]'.$j.'[/card]','[card]'.$text_arr[$j].'[/card]',$selected_text); 

                      } 

              } 

              $db->sql_freeresult($result); 

      }

I tested the SQL query and it's not the slow part. Now it's the eregi_replace. I wanted to use str_replace but it's case sensitive and str_ireplace is only available in PHP5 (I'm using PHP4).

So, I need some way to speed up the egeri_replace while loop.

Am I doing this as fast as possible?
Is there any way I could speed this search and replace up?

Can anyone help me?

Sorry if my english is bad.