allow a dir in .htaccess - apache

Question

i have the following htaccess file for my codeigniter installation.
Everything works, except that it blocks my xml files and urllist for google sitemap submission.
How would I allow the whole dir /xml or maybe .xml filetype to be added.
I have absolutely no idea how .htaccess files work...
Thanks!
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /
#Removes access to the system folder by users.
#Additionally this will allow you to create a System.php controller,
#previously this would not have been possible.
#'system' can be replaced if you have renamed your system folder.
RewriteCond %{REQUEST_URI} ^system.*
RewriteRule ^(.*)$ /index.php?/$1 [L]
#When your application folder isn't in the system folder
#This snippet prevents user access to the application folder
#Submitted by: Fabdrol
#Rename 'application' to your applications folder name.
RewriteCond %{REQUEST_URI} ^application.*
RewriteRule ^(.*)$ /index.php?/$1 [L]
#Checks to see if the user is attempting to access a valid file,
#such as an image or css document, if this isn't true it sends the
#request to index.php
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^(.*)$ index.php?/$1 [L]
# If we don't have mod_rewrite installed, all 404's
# can be sent to index.php, and everything works as normal.
# Submitted by: ElliotHaughin
ErrorDocument 404 /index.php

Answer 1

Below is my .htaccess file. I think the whole key is the RewriteCond (re-write condition).
You can simply put the file extensions or folder names that you want to be ignored.
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /
#Removes access to the system folder by users.
#Additionally this will allow you to create a System.php controller,
#previously this would not have been possible.
#'system' can be replaced if you have renamed your system folder.
RewriteCond $1 !^(index\.php|images|css|js|xml|uploads|robots\.txt|favicon\.ico)
RewriteRule ^(.*)$ index.php/$1 [L]
#Checks to see if the user is attempting to access a valid file,
#such as an image or css document, if this isn't true it sends the
#request to index.php
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^(.*)$ index.php/$1 [L]
#Set Charset to UTF-8
AddDefaultCharset UTF-8
</IfModule>
<IfModule !mod_rewrite.c>
# If we don't have mod_rewrite installed, all 404's
# can be sent to index.php, and everything works as normal.
# Submitted by: ElliotHaughin
ErrorDocument 404 /index.php
</IfModule>