Added Compat.php file
diff --git a/index.php b/index.php
index 7b47d08..eb364ec 100644
--- a/index.php
+++ b/index.php
@@ -1,5 +1,4 @@
 <?php
-
 /*
 |---------------------------------------------------------------
 | PHP ERROR REPORTING LEVEL
@@ -121,21 +120,6 @@
 
 /*
 |---------------------------------------------------------------
-| DEFINE E_STRICT
-|---------------------------------------------------------------
-|
-| Some older versions of PHP don't support the E_STRICT constant
-| so we need to explicitly define it otherwise the Exception class 
-| will generate errors.
-|
-*/
-if ( ! defined('E_STRICT'))
-{
-	define('E_STRICT', 2048);
-}
-
-/*
-|---------------------------------------------------------------
 | LOAD THE FRONT CONTROLLER
 |---------------------------------------------------------------
 |
diff --git a/system/codeigniter/CodeIgniter.php b/system/codeigniter/CodeIgniter.php
index f26f3e4..1b38f27 100644
--- a/system/codeigniter/CodeIgniter.php
+++ b/system/codeigniter/CodeIgniter.php
@@ -1 +1 @@
-<?php  if (!defined('BASEPATH')) exit('No direct script access allowed');
/**
 * CodeIgniter
 *
 * An open source application development framework for PHP 4.3.2 or newer
 *
 * @package		CodeIgniter
 * @author		Rick Ellis
 * @copyright	Copyright (c) 2006, EllisLab, Inc.
 * @license		http://www.codeigniter.com/user_guide/license.html
 * @link		http://www.codeigniter.com
 * @since		Version 1.0
 * @filesource
 */

// ------------------------------------------------------------------------

/**
 * System Front Controller
 *
 * Loads the base classes and executes the request.
 *
 * @package		CodeIgniter
 * @subpackage	codeigniter
 * @category	Front-controller
 * @author		Rick Ellis
 * @link		http://www.codeigniter.com/user_guide/
 */

// CI Version
define('CI_VERSION',	'1.5.5');

/*
 * ------------------------------------------------------
 *  Load the global functions
 * ------------------------------------------------------
 */
require(BASEPATH.'codeigniter/Common'.EXT);

/*
 * ------------------------------------------------------
 *  Define a custom error handler so we can log PHP errors
 * ------------------------------------------------------
 */
set_error_handler('_exception_handler');
set_magic_quotes_runtime(0); // Kill magic quotes

/*
 * ------------------------------------------------------
 *  Start the timer... tick tock tick tock...
 * ------------------------------------------------------
 */

$BM =& load_class('Benchmark');
$BM->mark('total_execution_time_start');
$BM->mark('loading_time_base_classes_start');

/*
 * ------------------------------------------------------
 *  Instantiate the hooks class
 * ------------------------------------------------------
 */

$EXT =& load_class('Hooks');

/*
 * ------------------------------------------------------
 *  Is there a "pre_system" hook?
 * ------------------------------------------------------
 */
$EXT->_call_hook('pre_system');

/*
 * ------------------------------------------------------
 *  Instantiate the base classes
 * ------------------------------------------------------
 */

$CFG =& load_class('Config');
$URI =& load_class('URI');
$RTR =& load_class('Router');
$OUT =& load_class('Output');

/*
 * ------------------------------------------------------
 *	Is there a valid cache file?  If so, we're done...
 * ------------------------------------------------------
 */

if ($EXT->_call_hook('cache_override') === FALSE)
{
	if ($OUT->_display_cache($CFG, $RTR) == TRUE)
	{
		exit;
	}
}

/*
 * ------------------------------------------------------
 *  Load the remaining base classes
 * ------------------------------------------------------
 */

$IN		=& load_class('Input');
$LANG	=& load_class('Language');

/*
 * ------------------------------------------------------
 *  Load the app controller and local controller
 * ------------------------------------------------------
 *
 *  Note: Due to the poor object handling in PHP 4 we'll
 *  conditionally load different versions of the base
 *  class.  Retaining PHP 4 compatibility requires a bit of a hack.
 *
 *  Note: The Loader class needs to be included first
 *
 */
if (floor(phpversion()) < 5)
{
	load_class('Loader', FALSE);
	require(BASEPATH.'codeigniter/Base4'.EXT);
}
else
{
	require(BASEPATH.'codeigniter/Base5'.EXT);
}

// Load the base controller class
load_class('Controller', FALSE);

// Load the local application controller
// Note: The Router class automatically validates the controller path.  If this include fails it 
// means that the default controller in the Routes.php file is not resolving to something valid.
if ( ! file_exists(APPPATH.'controllers/'.$RTR->fetch_directory().$RTR->fetch_class().EXT))
{
	show_error('Unable to load your default controller.  Please make sure the controller specified in your Routes.php file is valid.');
}

include(APPPATH.'controllers/'.$RTR->fetch_directory().$RTR->fetch_class().EXT);

// Set a mark point for benchmarking
$BM->mark('loading_time_base_classes_end');


/*
 * ------------------------------------------------------
 *  Security check
 * ------------------------------------------------------
 *
 *  None of the functions in the app controller or the
 *  loader class can be called via the URI, nor can
 *  controller functions that begin with an underscore
 */
$class  = $RTR->fetch_class();
$method = $RTR->fetch_method();


if ( ! class_exists($class)
	OR $method == 'controller'
	OR substr($method, 0, 1) == '_'
	OR in_array($method, get_class_methods('Controller'), TRUE)
	)
{
	show_404();
}

/*
 * ------------------------------------------------------
 *  Is there a "pre_controller" hook?
 * ------------------------------------------------------
 */
$EXT->_call_hook('pre_controller');

/*
 * ------------------------------------------------------
 *  Instantiate the controller and call requested method
 * ------------------------------------------------------
 */

// Mark a start point so we can benchmark the controller
$BM->mark('controller_execution_time_( '.$class.' / '.$method.' )_start');

// Instantiate the Controller and pass any global data that might exist
$assign_to_controller = ( ! isset($assign_to_controller)) ? NULL : $assign_to_controller;

$CI = new $class($assign_to_controller);

unset($assign_to_controller);

// Is this a scaffolding request?
if ($RTR->scaffolding_request === TRUE)
{
	if ($EXT->_call_hook('scaffolding_override') === FALSE)
	{
		$CI->_ci_scaffolding();
	}
}
else
{
	/*
	 * ------------------------------------------------------
	 *  Is there a "post_controller_constructor" hook?
	 * ------------------------------------------------------
	 */
	$EXT->_call_hook('post_controller_constructor');
	
	// Is there a "remap" function?
	if (method_exists($CI, '_remap'))
	{
		$CI->_remap($method);
	}
	else
	{
		if ( ! method_exists($CI, $method))
		{
			show_404();
		}

		// Call the requested method.
		// Any URI segments present (besides the class/function) will be passed to the method for convenience		
		call_user_func_array(array(&$CI, $method), array_slice($URI->rsegments, (($RTR->fetch_directory() == '') ? 2 : 3)));		
	}
}

// Mark a benchmark end point
$BM->mark('controller_execution_time_( '.$class.' / '.$method.' )_end');

/*
 * ------------------------------------------------------
 *  Is there a "post_controller" hook?
 * ------------------------------------------------------
 */
$EXT->_call_hook('post_controller');

/*
 * ------------------------------------------------------
 *  Send the final rendered output to the browser
 * ------------------------------------------------------
 */

if ($EXT->_call_hook('display_override') === FALSE)
{
	$OUT->_display();
}

/*
 * ------------------------------------------------------
 *  Is there a "post_system" hook?
 * ------------------------------------------------------
 */
$EXT->_call_hook('post_system');

/*
 * ------------------------------------------------------
 *  Close the DB connection if one exists
 * ------------------------------------------------------
 */
if (class_exists('CI_DB') AND isset($CI->db))
{
	$CI->db->close();
}


?>
\ No newline at end of file
+<?php  if (!defined('BASEPATH')) exit('No direct script access allowed');
/**
 * CodeIgniter
 *
 * An open source application development framework for PHP 4.3.2 or newer
 *
 * @package		CodeIgniter
 * @author		Rick Ellis
 * @copyright	Copyright (c) 2006, EllisLab, Inc.
 * @license		http://www.codeigniter.com/user_guide/license.html
 * @link		http://www.codeigniter.com
 * @since		Version 1.0
 * @filesource
 */

// ------------------------------------------------------------------------

/**
 * System Front Controller
 *
 * Loads the base classes and executes the request.
 *
 * @package		CodeIgniter
 * @subpackage	codeigniter
 * @category	Front-controller
 * @author		Rick Ellis
 * @link		http://www.codeigniter.com/user_guide/
 */

// CI Version
define('CI_VERSION',	'1.5.5');

/*
 * ------------------------------------------------------
 *  Load the global functions
 * ------------------------------------------------------
 */
require(BASEPATH.'codeigniter/Common'.EXT);

/*
 * ------------------------------------------------------
 *  Load the compatibility override functions
 * ------------------------------------------------------
 */
require(BASEPATH.'codeigniter/Compat'.EXT);
	
/*
 * ------------------------------------------------------
 *  Define a custom error handler so we can log PHP errors
 * ------------------------------------------------------
 */
set_error_handler('_exception_handler');
set_magic_quotes_runtime(0); // Kill magic quotes

/*
 * ------------------------------------------------------
 *  Start the timer... tick tock tick tock...
 * ------------------------------------------------------
 */

$BM =& load_class('Benchmark');
$BM->mark('total_execution_time_start');
$BM->mark('loading_time_base_classes_start');

/*
 * ------------------------------------------------------
 *  Instantiate the hooks class
 * ------------------------------------------------------
 */

$EXT =& load_class('Hooks');

/*
 * ------------------------------------------------------
 *  Is there a "pre_system" hook?
 * ------------------------------------------------------
 */
$EXT->_call_hook('pre_system');

/*
 * ------------------------------------------------------
 *  Instantiate the base classes
 * ------------------------------------------------------
 */

$CFG =& load_class('Config');
$URI =& load_class('URI');
$RTR =& load_class('Router');
$OUT =& load_class('Output');

/*
 * ------------------------------------------------------
 *	Is there a valid cache file?  If so, we're done...
 * ------------------------------------------------------
 */

if ($EXT->_call_hook('cache_override') === FALSE)
{
	if ($OUT->_display_cache($CFG, $RTR) == TRUE)
	{
		exit;
	}
}

/*
 * ------------------------------------------------------
 *  Load the remaining base classes
 * ------------------------------------------------------
 */

$IN		=& load_class('Input');
$LANG	=& load_class('Language');

/*
 * ------------------------------------------------------
 *  Load the app controller and local controller
 * ------------------------------------------------------
 *
 *  Note: Due to the poor object handling in PHP 4 we'll
 *  conditionally load different versions of the base
 *  class.  Retaining PHP 4 compatibility requires a bit of a hack.
 *
 *  Note: The Loader class needs to be included first
 *
 */
if (floor(phpversion()) < 5)
{
	load_class('Loader', FALSE);
	require(BASEPATH.'codeigniter/Base4'.EXT);
}
else
{
	require(BASEPATH.'codeigniter/Base5'.EXT);
}

// Load the base controller class
load_class('Controller', FALSE);

// Load the local application controller
// Note: The Router class automatically validates the controller path.  If this include fails it 
// means that the default controller in the Routes.php file is not resolving to something valid.
if ( ! file_exists(APPPATH.'controllers/'.$RTR->fetch_directory().$RTR->fetch_class().EXT))
{
	show_error('Unable to load your default controller.  Please make sure the controller specified in your Routes.php file is valid.');
}

include(APPPATH.'controllers/'.$RTR->fetch_directory().$RTR->fetch_class().EXT);

// Set a mark point for benchmarking
$BM->mark('loading_time_base_classes_end');


/*
 * ------------------------------------------------------
 *  Security check
 * ------------------------------------------------------
 *
 *  None of the functions in the app controller or the
 *  loader class can be called via the URI, nor can
 *  controller functions that begin with an underscore
 */
$class  = $RTR->fetch_class();
$method = $RTR->fetch_method();


if ( ! class_exists($class)
	OR $method == 'controller'
	OR substr($method, 0, 1) == '_'
	OR in_array($method, get_class_methods('Controller'), TRUE)
	)
{
	show_404();
}

/*
 * ------------------------------------------------------
 *  Is there a "pre_controller" hook?
 * ------------------------------------------------------
 */
$EXT->_call_hook('pre_controller');

/*
 * ------------------------------------------------------
 *  Instantiate the controller and call requested method
 * ------------------------------------------------------
 */

// Mark a start point so we can benchmark the controller
$BM->mark('controller_execution_time_( '.$class.' / '.$method.' )_start');

// Instantiate the Controller and pass any global data that might exist
$assign_to_controller = ( ! isset($assign_to_controller)) ? NULL : $assign_to_controller;

$CI = new $class($assign_to_controller);

unset($assign_to_controller);

// Is this a scaffolding request?
if ($RTR->scaffolding_request === TRUE)
{
	if ($EXT->_call_hook('scaffolding_override') === FALSE)
	{
		$CI->_ci_scaffolding();
	}
}
else
{
	/*
	 * ------------------------------------------------------
	 *  Is there a "post_controller_constructor" hook?
	 * ------------------------------------------------------
	 */
	$EXT->_call_hook('post_controller_constructor');
	
	// Is there a "remap" function?
	if (method_exists($CI, '_remap'))
	{
		$CI->_remap($method);
	}
	else
	{
		if ( ! method_exists($CI, $method))
		{
			show_404();
		}

		// Call the requested method.
		// Any URI segments present (besides the class/function) will be passed to the method for convenience		
		call_user_func_array(array(&$CI, $method), array_slice($URI->rsegments, (($RTR->fetch_directory() == '') ? 2 : 3)));		
	}
}

// Mark a benchmark end point
$BM->mark('controller_execution_time_( '.$class.' / '.$method.' )_end');

/*
 * ------------------------------------------------------
 *  Is there a "post_controller" hook?
 * ------------------------------------------------------
 */
$EXT->_call_hook('post_controller');

/*
 * ------------------------------------------------------
 *  Send the final rendered output to the browser
 * ------------------------------------------------------
 */

if ($EXT->_call_hook('display_override') === FALSE)
{
	$OUT->_display();
}

/*
 * ------------------------------------------------------
 *  Is there a "post_system" hook?
 * ------------------------------------------------------
 */
$EXT->_call_hook('post_system');

/*
 * ------------------------------------------------------
 *  Close the DB connection if one exists
 * ------------------------------------------------------
 */
if (class_exists('CI_DB') AND isset($CI->db))
{
	$CI->db->close();
}


?>
\ No newline at end of file
diff --git a/system/codeigniter/Compat.php b/system/codeigniter/Compat.php
new file mode 100644
index 0000000..3c5f70d
--- /dev/null
+++ b/system/codeigniter/Compat.php
@@ -0,0 +1,84 @@
+<?php  if (!defined('BASEPATH')) exit('No direct script access allowed');
+/**
+ * CodeIgniter
+ *
+ * An open source application development framework for PHP 4.3.2 or newer
+ *
+ * @package		CodeIgniter
+ * @author		Rick Ellis
+ * @copyright	Copyright (c) 2006, EllisLab, Inc.
+ * @license		http://www.codeigniter.com/user_guide/license.html
+ * @link		http://www.codeigniter.com
+ * @since		Version 1.0
+ * @filesource
+ */
+
+// ------------------------------------------------------------------------
+
+/**
+ * Compatibility Functions
+ *
+ * Function overrides for older versions of PHP or PHP environments missing
+ * certain extensions / libraries
+ *
+ * @package		CodeIgniter
+ * @subpackage	codeigniter
+ * @category	Compatibility Functions
+ * @author		EllisLab Development Team
+ * @link		http://www.codeigniter.com/user_guide/
+ */
+
+// ------------------------------------------------------------------------
+
+/*
+ * PHP versions prior to 5.0 don't support the E_STRICT constant
+ * so we need to explicitly define it otherwise the Exception class 
+ * will generate errors when running under PHP 4
+ *
+ */
+if ( ! defined('E_STRICT'))
+{
+	define('E_STRICT', 2048);
+}
+
+/**
+ * ctype_digit()
+ *
+ * Determines if a string is comprised only of digits
+ * http://us.php.net/manual/en/function.ctype_digit.php
+ *
+ * @access	public
+ * @param	string
+ * @return	bool
+ */
+if (! function_exists('ctype_digit'))
+{
+	function ctype_digit($str)
+	{
+		return ! preg_match('/[^0-9]/', $str);
+	}	
+}
+
+// --------------------------------------------------------------------
+
+/**
+ * ctype_alnum()
+ *
+ * Determines if a string is comprised of only alphanumeric characters
+ * http://us.php.net/manual/en/function.ctype-alnum.php
+ *
+ * @access	public
+ * @param	string
+ * @return	bool
+ */
+if (! function_exists('ctype_alnum'))
+{
+	function ctype_alnum($str)
+	{
+		return ! preg_match('/[^0-9a-z]/i', $str);
+	}	
+}
+
+// --------------------------------------------------------------------
+
+?>
\ No newline at end of file
diff --git a/user_guide/changelog.html b/user_guide/changelog.html
index 9bf7965..e879918 100644
--- a/user_guide/changelog.html
+++ b/user_guide/changelog.html
@@ -90,6 +90,7 @@
     <li>Added support for external urls in <kbd>form_open()</kbd>.</li>

     <li>Added a language entry for valid_ip validation error.</li>

     <li>Added titles to all user manual pages.</li>

+	<li>Added Compat.php to allow function overrides for older versions of PHP or PHP environments missing certain extensions / libraries</li>

     <li>Added <a href="http://codeigniter.com/user_guide/libraries/zip.html">Zip Encoding Class</a> to the table of contents of the userguide.</li>

     <li>Moved the safe mode and auth checks for the Email library into the constructor. </li>

     <li>Moved part of the userguide menu javascript to an external file.</li>

@@ -118,6 +119,7 @@
     <li>Fixed a bug in the <a href="./libraries/parser.html">parser class</a> where numeric data was ignored.</li>

     <li>Fixed a bug when loading plugin files as _plugin. and not _pi.</li>

     <li>Fixed a bug in the SQLite driver for PHP 4.</li>

+	<li>Fixed a bug in the clean_email() method of the Email class to allow for non-numeric / non-sequential array keys.</li>

     <li>Fixed an example of comma-separated emails in the email library documentation.</li>

     <li>Fixed an example in the Calendar library for Showing Next/Previous Month Links.</li>

     <li>Fixed a typo in the database language file.</li>