/phpBB/includes/functions.php

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<?php
/**
*
* @package phpBB3
* @version $Id$
* @copyright (c) 2005 phpBB Group
* @license http://opensource.org/licenses/gpl-license.php GNU Public License
*
*/

/**
* @ignore
*/
if (!defined('IN_PHPBB'))
{
	exit;
}

// Common global functions

/**
* set_var
*
* Set variable, used by {@link request_var the request_var function}
*
* @access private
*/
function set_var(&$result, $var, $type, $multibyte = false)
{
	settype($var, $type);
	$result = $var;

	if ($type == 'string')
	{
		$result = trim(htmlspecialchars(str_replace(array("\r\n", "\r", "\0"), array("\n", "\n", ''), $result), ENT_COMPAT, 'UTF-8'));

		if (!empty($result))
		{
			// Make sure multibyte characters are wellformed
			if ($multibyte)
			{
				if (!preg_match('/^./u', $result))
				{
					$result = '';
				}
			}
			else
			{
				// no multibyte, allow only ASCII (0-127)
				$result = preg_replace('/[\x80-\xFF]/', '?', $result);
			}
		}

		$result = (STRIP) ? stripslashes($result) : $result;
	}
}

/**
* request_var
*
* Used to get passed variable
*/
function request_var($var_name, $default, $multibyte = false, $cookie = false)
{
	if (!$cookie && isset($_COOKIE[$var_name]))
	{
		if (!isset($_GET[$var_name]) && !isset($_POST[$var_name]))
		{
			return (is_array($default)) ? array() : $default;
		}
		$_REQUEST[$var_name] = isset($_POST[$var_name]) ? $_POST[$var_name] : $_GET[$var_name];
	}

	$super_global = ($cookie) ? '_COOKIE' : '_REQUEST';
	if (!isset($GLOBALS[$super_global][$var_name]) || is_array($GLOBALS[$super_global][$var_name]) != is_array($default))
	{
		return (is_array($default)) ? array() : $default;
	}

	$var = $GLOBALS[$super_global][$var_name];
	if (!is_array($default))
	{
		$type = gettype($default);
	}
	else
	{
		list($key_type, $type) = each($default);
		$type = gettype($type);
		$key_type = gettype($key_type);
		if ($type == 'array')
		{
			reset($default);
			$default = current($default);
			list($sub_key_type, $sub_type) = each($default);
			$sub_type = gettype($sub_type);
			$sub_type = ($sub_type == 'array') ? 'NULL' : $sub_type;
			$sub_key_type = gettype($sub_key_type);
		}
	}

	if (is_array($var))
	{
		$_var = $var;
		$var = array();

		foreach ($_var as $k => $v)
		{
			set_var($k, $k, $key_type);
			if ($type == 'array' && is_array($v))
			{
				foreach ($v as $_k => $_v)
				{
					if (is_array($_v))
					{
						$_v = null;
					}
					set_var($_k, $_k, $sub_key_type, $multibyte);
					set_var($var[$k][$_k], $_v, $sub_type, $multibyte);
				}
			}
			else
			{
				if ($type == 'array' || is_array($v))
				{
					$v = null;
				}
				set_var($var[$k], $v, $type, $multibyte);
			}
		}
	}
	else
	{
		set_var($var, $var, $type, $multibyte);
	}

	return $var;
}

/**
* Sets a configuration option's value.
*
* Please note that this function does not update the is_dynamic value for
* an already existing config option.
*
* @param string $config_name   The configuration option's name
* @param string $config_value  New configuration value
* @param bool   $is_dynamic    Whether this variable should be cached (false) or
*                              if it changes too frequently (true) to be
*                              efficiently cached.
*
* @return null
*/
function set_config($config_name, $config_value, $is_dynamic = false)
{
	global $db, $cache, $config;

	$sql = 'UPDATE ' . CONFIG_TABLE . "
		SET config_value = '" . $db->sql_escape($config_value) . "'
		WHERE config_name = '" . $db->sql_escape($config_name) . "'";
	$db->sql_query($sql);

	if (!$db->sql_affectedrows() && !isset($config[$config_name]))
	{
		$sql = 'INSERT INTO ' . CONFIG_TABLE . ' ' . $db->sql_build_array('INSERT', array(
			'config_name'	=> $config_name,
			'config_value'	=> $config_value,
			'is_dynamic'	=> ($is_dynamic) ? 1 : 0));
		$db->sql_query($sql);
	}

	$config[$config_name] = $config_value;

	if (!$is_dynamic)
	{
		$cache->destroy('config');
	}
}

/**
* Increments an integer config value directly in the database.
*
* @param string $config_name   The configuration option's name
* @param int    $increment     Amount to increment by
* @param bool   $is_dynamic    Whether this variable should be cached (false) or
*                              if it changes too frequently (true) to be
*                              efficiently cached.
*
* @return null
*/
function set_config_count($config_name, $increment, $is_dynamic = false)
{
	global $db, $cache;

	switch ($db->sql_layer)
	{
		case 'firebird':
			// Precision must be from 1 to 18
			$sql_update = 'CAST(CAST(config_value as DECIMAL(18, 0)) + ' . (int) $increment . ' as VARCHAR(255))';
		break;

		case 'postgres':
			// Need to cast to text first for PostgreSQL 7.x
			$sql_update = 'CAST(CAST(config_value::text as DECIMAL(255, 0)) + ' . (int) $increment . ' as VARCHAR(255))';
		break;

		// MySQL, SQlite, mssql, mssql_odbc, oracle
		default:
			$sql_update = 'config_value + ' . (int) $increment;
		break;
	}

	$db->sql_query('UPDATE ' . CONFIG_TABLE . ' SET config_value = ' . $sql_update . " WHERE config_name = '" . $db->sql_escape($config_name) . "'");

	if (!$is_dynamic)
	{
		$cache->destroy('config');
	}
}

/**
* Generates an alphanumeric random string of given length
*
* @return string
*/
function gen_rand_string($num_chars = 8)
{
	// [a, z] + [0, 9] = 36
	return substr(strtoupper(base_convert(unique_id(), 16, 36)), 0, $num_chars);
}

/**
* Generates a user-friendly alphanumeric random string of given length
* We remove 0 and O so users cannot confuse those in passwords etc.
*
* @return string
*/
function gen_rand_string_friendly($num_chars = 8)
{
	$rand_str = unique_id();

	// Remove Z and Y from the base_convert(), replace 0 with Z and O with Y
	// [a, z] + [0, 9] - {z, y} = [a, z] + [0, 9] - {0, o} = 34
	$rand_str = str_replace(array('0', 'O'), array('Z', 'Y'), strtoupper(base_convert($rand_str, 16, 34)));

	return substr($rand_str, 0, $num_chars);
}

/**
* Return unique id
* @param string $extra additional entropy
*/
function unique_id($extra = 'c')
{
	static $dss_seeded = false;
	global $config;

	$val = $config['rand_seed'] . microtime();
	$val = md5($val);
	$config['rand_seed'] = md5($config['rand_seed'] . $val . $extra);

	if ($dss_seeded !== true && ($config['rand_seed_last_update'] < time() - rand(1,10)))
	{
		set_config('rand_seed_last_update', time(), true);
		set_config('rand_seed', $config['rand_seed'], true);
		$dss_seeded = true;
	}

	return substr($val, 4, 16);
}

/**
* Wrapper for mt_rand() which allows swapping $min and $max parameters.
*
* PHP does not allow us to swap the order of the arguments for mt_rand() anymore.
* (since PHP 5.3.4, see http://bugs.php.net/46587)
*
* @param int $min		Lowest value to be returned
* @param int $max		Highest value to be returned
*
* @return int			Random integer between $min and $max (or $max and $min)
*/
function phpbb_mt_rand($min, $max)
{
	return ($min > $max) ? mt_rand($max, $min) : mt_rand($min, $max);
}

/**
* Wrapper for getdate() which returns the equivalent array for UTC timestamps.
*
* @param int $time		Unix timestamp (optional)
*
* @return array			Returns an associative array of information related to the timestamp.
*						See http://www.php.net/manual/en/function.getdate.php
*/
function phpbb_gmgetdate($time = false)
{
	if ($time === false)
	{
		$time = time();
	}

	// getdate() interprets timestamps in local time.
	// What follows uses the fact that getdate() and
	// date('Z') balance each other out.
	return getdate($time - date('Z'));
}

/**
* Return formatted string for filesizes
*
* @param mixed	$value			filesize in bytes
*								(non-negative number; int, float or string)
* @param bool	$string_only	true if language string should be returned
* @param array	$allowed_units	only allow these units (data array indexes)
*
* @return mixed					data array if $string_only is false
* @author bantu
*/
function get_formatted_filesize($value, $string_only = true, $allowed_units = false)
{
	global $user;

	$available_units = array(
		'tb' => array(
			'min' 		=> 1099511627776, // pow(2, 40)
			'index'		=> 4,
			'si_unit'	=> 'TB',
			'iec_unit'	=> 'TIB',
		),
		'gb' => array(
			'min' 		=> 1073741824, // pow(2, 30)
			'index'		=> 3,
			'si_unit'	=> 'GB',
			'iec_unit'	=> 'GIB',
		),
		'mb' => array(
			'min'		=> 1048576, // pow(2, 20)
			'index'		=> 2,
			'si_unit'	=> 'MB',
			'iec_unit'	=> 'MIB',
		),
		'kb' => array(
			'min'		=> 1024, // pow(2, 10)
			'index'		=> 1,
			'si_unit'	=> 'KB',
			'iec_unit'	=> 'KIB',
		),
		'b' => array(
			'min'		=> 0,
			'index'		=> 0,
			'si_unit'	=> 'BYTES', // Language index
			'iec_unit'	=> 'BYTES',  // Language index
		),
	);

	foreach ($available_units as $si_identifier => $unit_info)
	{
		if (!empty($allowed_units) && $si_identifier != 'b' && !in_array($si_identifier, $allowed_units))
		{
			continue;
		}

		if ($value >= $unit_info['min'])
		{
			$unit_info['si_identifier'] = $si_identifier;

			break;
		}
	}
	unset($available_units);

	for ($i = 0; $i < $unit_info['index']; $i++)
	{
		$value /= 1024;
	}
	$value = round($value, 2);

	// Lookup units in language dictionary
	$unit_info['si_unit'] = (isset($user->lang[$unit_info['si_unit']])) ? $user->lang[$unit_info['si_unit']] : $unit_info['si_unit'];
	$unit_info['iec_unit'] = (isset($user->lang[$unit_info['iec_unit']])) ? $user->lang[$unit_info['iec_unit']] : $unit_info['iec_unit'];

	// Default to IEC
	$unit_info['unit'] = $unit_info['iec_unit'];

	if (!$string_only)
	{
		$unit_info['value'] = $value;

		return $unit_info;
	}

	return $value  . ' ' . $unit_info['unit'];
}

/**
* Determine whether we are approaching the maximum execution time. Should be called once
* at the beginning of the script in which it's used.
* @return	bool	Either true if the maximum execution time is nearly reached, or false
*					if some time is still left.
*/
function still_on_time($extra_time = 15)
{
	static $max_execution_time, $start_time;

	$time = explode(' ', microtime());
	$current_time = $time[0] + $time[1];

	if (empty($max_execution_time))
	{
		$max_execution_time = (function_exists('ini_get')) ? (int) @ini_get('max_execution_time') : (int) @get_cfg_var('max_execution_time');

		// If zero, then set to something higher to not let the user catch the ten seconds barrier.
		if ($max_execution_time === 0)
		{
			$max_execution_time = 50 + $extra_time;
		}

		$max_execution_time = min(max(10, ($max_execution_time - $extra_time)), 50);

		// For debugging purposes
		// $max_execution_time = 10;

		global $starttime;
		$start_time = (empty($starttime)) ? $current_time : $starttime;
	}

	return (ceil($current_time - $start_time) < $max_execution_time) ? true : false;
}

/**
*
* @version Version 0.1 / slightly modified for phpBB 3.0.x (using $H$ as hash type identifier)
*
* Portable PHP password hashing framework.
*
* Written by Solar Designer <solar at openwall.com> in 2004-2006 and placed in
* the public domain.
*
* There's absolutely no warranty.
*
* The homepage URL for this framework is:
*
*	http://www.openwall.com/phpass/
*
* Please be sure to update the Version line if you edit this file in any way.
* It is suggested that you leave the main version number intact, but indicate
* your project name (after the slash) and add your own revision information.
*
* Please do not change the "private" password hashing method implemented in
* here, thereby making your hashes incompatible.  However, if you must, please
* change the hash type identifier (the "$P$") to something different.
*
* Obviously, since this code is in the public domain, the above are not
* requirements (there can be none), but merely suggestions.
*
*
* Hash the password
*/
function phpbb_hash($password)
{
	$itoa64 = './0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz';

	$random_state = unique_id();
	$random = '';
	$count = 6;

	if (($fh = @fopen('/dev/urandom', 'rb')))
	{
		$random = fread($fh, $count);
		fclose($fh);
	}

	if (strlen($random) < $count)
	{
		$random = '';

		for ($i = 0; $i < $count; $i += 16)
		{
			$random_state = md5(unique_id() . $random_state);
			$random .= pack('H*', md5($random_state));
		}
		$random = substr($random, 0, $count);
	}

	$hash = _hash_crypt_private($password, _hash_gensalt_private($random, $itoa64), $itoa64);

	if (strlen($hash) == 34)
	{
		return $hash;
	}

	return md5($password);
}

/**
* Check for correct password
*
* @param string $password The password in plain text
* @param string $hash The stored password hash
*
* @return bool Returns true if the password is correct, false if not.
*/
function phpbb_check_hash($password, $hash)
{
	if (strlen($password) > 4096)
	{
		// If the password is too huge, we will simply reject it
		// and not let the server try to hash it.
		return false;
	}

	$itoa64 = './0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz';
	if (strlen($hash) == 34)
	{
		return (_hash_crypt_private($password, $hash, $itoa64) === $hash) ? true : false;
	}

	return (md5($password) === $hash) ? true : false;
}

/**
* Generate salt for hash generation
*/
function _hash_gensalt_private($input, &$itoa64, $iteration_count_log2 = 6)
{
	if ($iteration_count_log2 < 4 || $iteration_count_log2 > 31)
	{
		$iteration_count_log2 = 8;
	}

	$output = '$H$';
	$output .= $itoa64[min($iteration_count_log2 + ((PHP_VERSION >= 5) ? 5 : 3), 30)];
	$output .= _hash_encode64($input, 6, $itoa64);

	return $output;
}

/**
* Encode hash
*/
function _hash_encode64($input, $count, &$itoa64)
{
	$output = '';
	$i = 0;

	do
	{
		$value = ord($input[$i++]);
		$output .= $itoa64[$value & 0x3f];

		if ($i < $count)
		{
			$value |= ord($input[$i]) << 8;
		}

		$output .= $itoa64[($value >> 6) & 0x3f];

		if ($i++ >= $count)
		{
			break;
		}

		if ($i < $count)
		{
			$value |= ord($input[$i]) << 16;
		}

		$output .= $itoa64[($value >> 12) & 0x3f];

		if ($i++ >= $count)
		{
			break;
		}

		$output .= $itoa64[($value >> 18) & 0x3f];
	}
	while ($i < $count);

	return $output;
}

/**
* The crypt function/replacement
*/
function _hash_crypt_private($password, $setting, &$itoa64)
{
	$output = '*';

	// Check for correct hash
	if (substr($setting, 0, 3) != '$H$' && substr($setting, 0, 3) != '$P$')
	{
		return $output;
	}

	$count_log2 = strpos($itoa64, $setting[3]);

	if ($count_log2 < 7 || $count_log2 > 30)
	{
		return $output;
	}

	$count = 1 << $count_log2;
	$salt = substr($setting, 4, 8);

	if (strlen($salt) != 8)
	{
		return $output;
	}

	/**
	* We're kind of forced to use MD5 here since it's the only
	* cryptographic primitive available in all versions of PHP
	* currently in use.  To implement our own low-level crypto
	* in PHP would result in much worse performance and
	* consequently in lower iteration counts and hashes that are
	* quicker to crack (by non-PHP code).
	*/
	if (PHP_VERSION >= 5)
	{
		$hash = md5($salt . $password, true);
		do
		{
			$hash = md5($hash . $password, true);
		}
		while (--$count);
	}
	else
	{
		$hash = pack('H*', md5($salt . $password));
		do
		{
			$hash = pack('H*', md5($hash . $password));
		}
		while (--$count);
	}

	$output = substr($setting, 0, 12);
	$output .= _hash_encode64($hash, 16, $itoa64);

	return $output;
}

/**
* Hashes an email address to a big integer
*
* @param string $email		Email address
*
* @return string			Unsigned Big Integer
*/
function phpbb_email_hash($email)
{
	return sprintf('%u', crc32(strtolower($email))) . strlen($email);
}

/**
* Wrapper for version_compare() that allows using uppercase A and B
* for alpha and beta releases.
*
* See http://www.php.net/manual/en/function.version-compare.php
*
* @param string $version1		First version number
* @param string $version2		Second version number
* @param string $operator		Comparison operator (optional)
*
* @return mixed					Boolean (true, false) if comparison operator is specified.
*								Integer (-1, 0, 1) otherwise.
*/
function phpbb_version_compare($version1, $version2, $operator = null)
{
	$version1 = strtolower($version1);
	$version2 = strtolower($version2);

	if (is_null($operator))
	{
		return version_compare($version1, $version2);
	}
	else
	{
		return version_compare($version1, $version2, $operator);
	}
}

/**
* Global function for chmodding directories and files for internal use
*
* This function determines owner and group whom the file belongs to and user and group of PHP and then set safest possible file permissions.
* The function determines owner and group from common.php file and sets the same to the provided file.
* The function uses bit fields to build the permissions.
* The function sets the appropiate execute bit on directories.
*
* Supported constants representing bit fields are:
*
* CHMOD_ALL - all permissions (7)
* CHMOD_READ - read permission (4)
* CHMOD_WRITE - write permission (2)
* CHMOD_EXECUTE - execute permission (1)
*
* NOTE: The function uses POSIX extension and fileowner()/filegroup() functions. If any of them is disabled, this function tries to build proper permissions, by calling is_readable() and is_writable() functions.
*
* @param string	$filename	The file/directory to be chmodded
* @param int	$perms		Permissions to set
*
* @return bool	true on success, otherwise false
* @author faw, phpBB Group
*/
function phpbb_chmod($filename, $perms = CHMOD_READ)
{
	static $_chmod_info;

	// Return if the file no longer exists.
	if (!file_exists($filename))
	{
		return false;
	}

	// Determine some common vars
	if (empty($_chmod_info))
	{
		if (!function_exists('fileowner') || !function_exists('filegroup'))
		{
			// No need to further determine owner/group - it is unknown
			$_chmod_info['process'] = false;
		}
		else
		{
			global $phpbb_root_path, $phpEx;

			// Determine owner/group of common.php file and the filename we want to change here
			$common_php_owner = @fileowner($phpbb_root_path . 'common.' . $phpEx);
			$common_php_group = @filegroup($phpbb_root_path . 'common.' . $phpEx);

			// And the owner and the groups PHP is running under.
			$php_uid = (function_exists('posix_getuid')) ? @posix_getuid() : false;
			$php_gids = (function_exists('posix_getgroups')) ? @posix_getgroups() : false;

			// If we are unable to get owner/group, then do not try to set them by guessing
			if (!$php_uid || empty($php_gids) || !$common_php_owner || !$common_php_group)
			{
				$_chmod_info['process'] = false;
			}
			else
			{
				$_chmod_info = array(
					'process'		=> true,
					'common_owner'	=> $common_php_owner,
					'common_group'	=> $common_php_group,
					'php_uid'		=> $php_uid,
					'php_gids'		=> $php_gids,
				);
			}
		}
	}

	if ($_chmod_info['process'])
	{
		$file_uid = @fileowner($filename);
		$file_gid = @filegroup($filename);

		// Change owner
		if (@chown($filename, $_chmod_info['common_owner']))
		{
			clearstatcache();
			$file_uid = @fileowner($filename);
		}

		// Change group
		if (@chgrp($filename, $_chmod_info['common_group']))
		{
			clearstatcache();
			$file_gid = @filegroup($filename);
		}

		// If the file_uid/gid now match the one from common.php we can process further, else we are not able to change something
		if ($file_uid != $_chmod_info['common_owner'] || $file_gid != $_chmod_info['common_group'])
		{
			$_chmod_info['process'] = false;
		}
	}

	// Still able to process?
	if ($_chmod_info['process'])
	{
		if ($file_uid == $_chmod_info['php_uid'])
		{
			$php = 'owner';
		}
		else if (in_array($file_gid, $_chmod_info['php_gids']))
		{
			$php = 'group';
		}
		else
		{
			// Since we are setting the everyone bit anyway, no need to do expensive operations
			$_chmod_info['process'] = false;
		}
	}

	// We are not able to determine or change something
	if (!$_chmod_info['process'])
	{
		$php = 'other';
	}

	// Owner always has read/write permission
	$owner = CHMOD_READ | CHMOD_WRITE;
	if (is_dir($filename))
	{
		$owner |= CHMOD_EXECUTE;

		// Only add execute bit to the permission if the dir needs to be readable
		if ($perms & CHMOD_READ)
		{
			$perms |= CHMOD_EXECUTE;
		}
	}

	switch ($php)
	{
		case 'owner':
			$result = @chmod($filename, ($owner << 6) + (0 << 3) + (0 << 0));

			clearstatcache();

			if (is_readable($filename) && phpbb_is_writable($filename))
			{
				break;
			}

		case 'group':
			$result = @chmod($filename, ($owner << 6) + ($perms << 3) + (0 << 0));

			clearstatcache();

			if ((!($perms & CHMOD_READ) || is_readable($filename)) && (!($perms & CHMOD_WRITE) || phpbb_is_writable($filename)))
			{
				break;
			}

		case 'other':
			$result = @chmod($filename, ($owner << 6) + ($perms << 3) + ($perms << 0));

			clearstatcache();

			if ((!($perms & CHMOD_READ) || is_readable($filename)) && (!($perms & CHMOD_WRITE) || phpbb_is_writable($filename)))
			{
				break;
			}

		default:
			return false;
		break;
	}

	return $result;
}

/**
* Test if a file/directory is writable
*
* This function calls the native is_writable() when not running under
* Windows and it is not disabled.
*
* @param string $file Path to perform write test on
* @return bool True when the path is writable, otherwise false.
*/
function phpbb_is_writable($file)
{
	if (strtolower(substr(PHP_OS, 0, 3)) === 'win' || !function_exists('is_writable'))
	{
		if (file_exists($file))
		{
			// Canonicalise path to absolute path
			$file = phpbb_realpath($file);

			if (is_dir($file))
			{
				// Test directory by creating a file inside the directory
				$result = @tempnam($file, 'i_w');

				if (is_string($result) && file_exists($result))
				{
					unlink($result);

					// Ensure the file is actually in the directory (returned realpathed)
					return (strpos($result, $file) === 0) ? true : false;
				}
			}
			else
			{
				$handle = @fopen($file, 'r+');

				if (is_resource($handle))
				{
					fclose($handle);
					return true;
				}
			}
		}
		else
		{
			// file does not exist test if we can write to the directory
			$dir = dirname($file);

			if (file_exists($dir) && is_dir($dir) && phpbb_is_writable($dir))
			{
				return true;
			}
		}

		return false;
	}
	else
	{
		return is_writable($file);
	}
}

// Compatibility functions

if (!function_exists('array_combine'))
{
	/**
	* A wrapper for the PHP5 function array_combine()
	* @param array $keys contains keys for the resulting array
	* @param array $values contains values for the resulting array
	*
	* @return Returns an array by using the values from the keys array as keys and the
	* 	values from the values array as the corresponding values. Returns false if the
	* 	number of elements for each array isn't equal or if the arrays are empty.
	*/
	function array_combine($keys, $values)
	{
		$keys = array_values($keys);
		$values = array_values($values);

		$n = sizeof($keys);
		$m = sizeof($values);
		if (!$n || !$m || ($n != $m))
		{
			return false;
		}

		$combined = array();
		for ($i = 0; $i < $n; $i++)
		{
			$combined[$keys[$i]] = $values[$i];
		}
		return $combined;
	}
}

if (!function_exists('str_split'))
{
	/**
	* A wrapper for the PHP5 function str_split()
	* @param array $string contains the string to be converted
	* @param array $split_length contains the length of each chunk
	*
	* @return  Converts a string to an array. If the optional split_length parameter is specified,
	*  	the returned array will be broken down into chunks with each being split_length in length,
	*  	otherwise each chunk will be one character in length. FALSE is returned if split_length is
	*  	less than 1. If the split_length length exceeds the length of string, the entire string is
	*  	returned as the first (and only) array element.
	*/
	function str_split($string, $split_length = 1)
	{
		if ($split_length < 1)
		{
			return false;
		}
		else if ($split_length >= strlen($string))
		{
			return array($string);
		}
		else
		{
			preg_match_all('#.{1,' . $split_length . '}#s', $string, $matches);
			return $matches[0];
		}
	}
}

if (!function_exists('stripos'))
{
	/**
	* A wrapper for the PHP5 function stripos
	* Find position of first occurrence of a case-insensitive string
	*
	* @param string $haystack is the string to search in
	* @param string $needle is the string to search for
	*
	* @return mixed Returns the numeric position of the first occurrence of needle in the haystack string. Unlike strpos(), stripos() is case-insensitive.
	* Note that the needle may be a string of one or more characters.
	* If needle is not found, stripos() will return boolean FALSE.
	*/
	function stripos($haystack, $needle)
	{
		if (preg_match('#' . preg_quote($needle, '#') . '#i', $haystack, $m))
		{
			return strpos($haystack, $m[0]);
		}

		return false;
	}
}

/**
* Checks if a path ($path) is absolute or relative
*
* @param string $path Path to check absoluteness of
* @return boolean
*/
function is_absolute($path)
{
	return (isset($path[0]) && $path[0] == '/' || preg_match('#^[a-z]:[/\\\]#i', $path)) ? true : false;
}

/**
* @author Chris Smith <chris@project-minerva.org>
* @copyright 2006 Project Minerva Team
* @param string $path The path which we should attempt to resolve.
* @return mixed
*/
function phpbb_own_realpath($path)
{
	// Now to perform funky shizzle

	// Switch to use UNIX slashes
	$path = str_replace(DIRECTORY_SEPARATOR, '/', $path);
	$path_prefix = '';

	// Determine what sort of path we have
	if (is_absolute($path))
	{
		$absolute = true;

		if ($path[0] == '/')
		{
			// Absolute path, *NIX style
			$path_prefix = '';
		}
		else
		{
			// Absolute path, Windows style
			// Remove the drive letter and colon
			$path_prefix = $path[0] . ':';
			$path = substr($path, 2);
		}
	}
	else
	{
		// Relative Path
		// Prepend the current working directory
		if (function_exists('getcwd'))
		{
			// This is the best method, hopefully it is enabled!
			$path = str_replace(DIRECTORY_SEPARATOR, '/', getcwd()) . '/' . $path;
			$absolute = true;
			if (preg_match('#^[a-z]:#i', $path))
			{
				$path_prefix = $path[0] . ':';
				$path = substr($path, 2);
			}
			else
			{
				$path_prefix = '';
			}
		}
		else if (isset($_SERVER['SCRIPT_FILENAME']) && !empty($_SERVER['SCRIPT_FILENAME']))
		{
			// Warning: If chdir() has been used this will lie!
			// Warning: This has some problems sometime (CLI can create them easily)
			$path = str_replace(DIRECTORY_SEPARATOR, '/', dirname($_SERVER['SCRIPT_FILENAME'])) . '/' . $path;
			$absolute = true;
			$path_prefix = '';
		}
		else
		{
			// We have no way of getting the absolute path, just run on using relative ones.
			$absolute = false;
			$path_prefix = '.';
		}
	}

	// Remove any repeated slashes
	$path = preg_replace('#/{2,}#', '/', $path);

	// Remove the slashes from the start and end of the path
	$path = trim($path, '/');

	// Break the string into little bits for us to nibble on
	$bits = explode('/', $path);

	// Remove any . in the path, renumber array for the loop below
	$bits = array_values(array_diff($bits, array('.')));

	// Lets get looping, run over and resolve any .. (up directory)
	for ($i = 0, $max = sizeof($bits); $i < $max; $i++)
	{
		// @todo Optimise
		if ($bits[$i] == '..' )
		{
			if (isset($bits[$i - 1]))
			{
				if ($bits[$i - 1] != '..')
				{
					// We found a .. and we are able to traverse upwards, lets do it!
					unset($bits[$i]);
					unset($bits[$i - 1]);
					$i -= 2;
					$max -= 2;
					$bits = array_values($bits);
				}
			}
			else if ($absolute) // ie. !isset($bits[$i - 1]) && $absolute
			{
				// We have an absolute path trying to descend above the root of the filesystem
				// ... Error!
				return false;
			}
		}
	}

	// Prepend the path prefix
	array_unshift($bits, $path_prefix);

	$resolved = '';

	$max = sizeof($bits) - 1;

	// Check if we are able to resolve symlinks, Windows cannot.
	$symlink_resolve = (function_exists('readlink')) ? true : false;

	foreach ($bits as $i => $bit)
	{
		if (@is_dir("$resolved/$bit") || ($i == $max && @is_file("$resolved/$bit")))
		{
			// Path Exists
			if ($symlink_resolve && is_link("$resolved/$bit") && ($link = readlink("$resolved/$bit")))
			{
				// Resolved a symlink.
				$resolved = $link . (($i == $max) ? '' : '/');
				continue;
			}
		}
		else
		{
			// Something doesn't exist here!
			// This is correct realpath() behaviour but sadly open_basedir and safe_mode make this problematic
			// return false;
		}
		$resolved .= $bit . (($i == $max) ? '' : '/');
	}

	// @todo If the file exists fine and open_basedir only has one path we should be able to prepend it
	// because we must be inside that basedir, the question is where...
	// @internal The slash in is_dir() gets around an open_basedir restriction
	if (!@file_exists($resolved) || (!@is_dir($resolved . '/') && !is_file($resolved)))
	{
		return false;
	}

	// Put the slashes back to the native operating systems slashes
	$resolved = str_replace('/', DIRECTORY_SEPARATOR, $resolved);

	// Check for DIRECTORY_SEPARATOR at the end (and remove it!)
	if (substr($resolved, -1) == DIRECTORY_SEPARATOR)
	{
		return substr($resolved, 0, -1);
	}

	return $resolved; // We got here, in the end!
}

if (!function_exists('realpath'))
{
	/**
	* A wrapper for realpath
	* @ignore
	*/
	function phpbb_realpath($path)
	{
		return phpbb_own_realpath($path);
	}
}
else
{
	/**
	* A wrapper for realpath
	*/
	function phpbb_realpath($path)
	{
		$realpath = realpath($path);

		// Strangely there are provider not disabling realpath but returning strange values. :o
		// We at least try to cope with them.
		if ($realpath === $path || $realpath === false)
		{
			return phpbb_own_realpath($path);
		}

		// Check for DIRECTORY_SEPARATOR at the end (and remove it!)
		if (substr($realpath, -1) == DIRECTORY_SEPARATOR)
		{
			$realpath = substr($realpath, 0, -1);
		}

		return $realpath;
	}
}

/**
* Eliminates useless . and .. components from specified path.
*
* @param string $path Path to clean
* @return string Cleaned path
*/
function phpbb_clean_path($path)
{
	$exploded = explode('/', $path);
	$filtered = array();
	foreach ($exploded as $part)
	{
		if ($part === '.' && !empty($filtered))
		{
			continue;
		}

		if ($part === '..' && !empty($filtered) && $filtered[sizeof($filtered) - 1] !== '..')
		{
			array_pop($filtered);
		}
		else
		{
			$filtered[] = $part;
		}
	}
	$path = implode('/', $filtered);
	return $path;
}

if (!function_exists('htmlspecialchars_decode'))
{
	/**
	* A wrapper for htmlspecialchars_decode
	* @ignore
	*/
	function htmlspecialchars_decode($string, $quote_style = ENT_COMPAT)
	{
		return strtr($string, array_flip(get_html_translation_table(HTML_SPECIALCHARS, $quote_style)));
	}
}

// functions used for building option fields

/**
* Pick a language, any language ...
*/
function language_select($default = '')
{
	global $db;

	$sql = 'SELECT lang_iso, lang_local_name
		FROM ' . LANG_TABLE . '
		ORDER BY lang_english_name';
	$result = $db->sql_query($sql);

	$lang_options = '';
	while ($row = $db->sql_fetchrow($result))
	{
		$selected = ($row['lang_iso'] == $default) ? ' selected="selected"' : '';
		$lang_options .= '<option value="' . $row['lang_iso'] . '"' . $selected . '>' . $row['lang_local_name'] . '</option>';
	}
	$db->sql_freeresult($result);

	return $lang_options;
}

/**
* Pick a template/theme combo,
*/
function style_select($default = '', $all = false)
{
	global $db;

	$sql_where = (!$all) ? 'WHERE style_active = 1 ' : '';
	$sql = 'SELECT style_id, style_name
		FROM ' . STYLES_TABLE . "
		$sql_where
		ORDER BY style_name";
	$result = $db->sql_query($sql);

	$style_options = '';
	while ($row = $db->sql_fetchrow($result))
	{
		$selected = ($row['style_id'] == $default) ? ' selected="selected"' : '';
		$style_options .= '<option value="' . $row['style_id'] . '"' . $selected . '>' . $row['style_name'] . '</option>';
	}
	$db->sql_freeresult($result);

	return $style_options;
}

/**
* Pick a timezone
*/
function tz_select($default = '', $truncate = false)
{
	global $user;

	$tz_select = '';
	foreach ($user->lang['tz_zones'] as $offset => $zone)
	{
		if ($truncate)
		{
			$zone_trunc = truncate_string($zone, 50, 255, false, '...');
		}
		else
		{
			$zone_trunc = $zone;
		}

		if (is_numeric($offset))
		{
			$selected = ($offset == $default) ? ' selected="selected"' : '';
			$tz_select .= '<option title="' . $zone . '" value="' . $offset . '"' . $selected . '>' . $zone_trunc . '</option>';
		}
	}

	return $tz_select;
}

// Functions handling topic/post tracking/marking

/**
* Marks a topic/forum as read
* Marks a topic as posted to
*
* @param int $user_id can only be used with $mode == 'post'
*/
function markread($mode, $forum_id = false, $topic_id = false, $post_time = 0, $user_id = 0)
{
	global $db, $user, $config;

	if ($mode == 'all')
	{
		if ($forum_id === false || !sizeof($forum_id))
		{
			if ($config['load_db_lastread'] && $user->data['is_registered'])
			{
				// Mark all forums read (index page)
				$db->sql_query('DELETE FROM ' . TOPICS_TRACK_TABLE . " WHERE user_id = {$user->data['user_id']}");
				$db->sql_query('DELETE FROM ' . FORUMS_TRACK_TABLE . " WHERE user_id = {$user->data['user_id']}");
				$db->sql_query('UPDATE ' . USERS_TABLE . ' SET user_lastmark = ' . time() . " WHERE user_id = {$user->data['user_id']}");
			}
			else if ($config['load_anon_lastread'] || $user->data['is_registered'])
			{
				$tracking_topics = (isset($_COOKIE[$config['cookie_name'] . '_track'])) ? ((STRIP) ? stripslashes($_COOKIE[$config['cookie_name'] . '_track']) : $_COOKIE[$config['cookie_name'] . '_track']) : '';
				$tracking_topics = ($tracking_topics) ? tracking_unserialize($tracking_topics) : array();

				unset($tracking_topics['tf']);
				unset($tracking_topics['t']);
				unset($tracking_topics['f']);
				$tracking_topics['l'] = base_convert(time() - $config['board_startdate'], 10, 36);

				$user->set_cookie('track', tracking_serialize($tracking_topics), time() + 31536000);
				$_COOKIE[$config['cookie_name'] . '_track'] = (STRIP) ? addslashes(tracking_serialize($tracking_topics)) : tracking_serialize($tracking_topics);

				unset($tracking_topics);

				if ($user->data['is_registered'])
				{
					$db->sql_query('UPDATE ' . USERS_TABLE . ' SET user_lastmark = ' . time() . " WHERE user_id = {$user->data['user_id']}");
				}
			}
		}

		return;
	}
	else if ($mode == 'topics')
	{
		// Mark all topics in forums read
		if (!is_array($forum_id))
		{
			$forum_id = array($forum_id);
		}

		// Add 0 to forums array to mark global announcements correctly
		// $forum_id[] = 0;

		if ($config['load_db_lastread'] && $user->data['is_registered'])
		{
			$sql = 'DELETE FROM ' . TOPICS_TRACK_TABLE . "
				WHERE user_id = {$user->data['user_id']}
					AND " . $db->sql_in_set('forum_id', $forum_id);
			$db->sql_query($sql);

			$sql = 'SELECT forum_id
				FROM ' . FORUMS_TRACK_TABLE . "
				WHERE user_id = {$user->data['user_id']}
					AND " . $db->sql_in_set('forum_id', $forum_id);
			$result = $db->sql_query($sql);

			$sql_update = array();
			while ($row = $db->sql_fetchrow($result))
			{
				$sql_update[] = (int) $row['forum_id'];
			}
			$db->sql_freeresult($result);

			if (sizeof($sql_update))
			{
				$sql = 'UPDATE ' . FORUMS_TRACK_TABLE . '
					SET mark_time = ' . time() . "
					WHERE user_id = {$user->data['user_id']}
						AND " . $db->sql_in_set('forum_id', $sql_update);
				$db->sql_query($sql);
			}

			if ($sql_insert = array_diff($forum_id, $sql_update))
			{
				$sql_ary = array();
				foreach ($sql_insert as $f_id)
				{
					$sql_ary[] = array(
						'user_id'	=> (int) $user->data['user_id'],
						'forum_id'	=> (int) $f_id,
						'mark_time'	=> time()
					);
				}

				$db->sql_multi_insert(FORUMS_TRACK_TABLE, $sql_ary);
			}
		}
		else if ($config['load_anon_lastread'] || $user->data['is_registered'])
		{
			$tracking = (isset($_COOKIE[$config['cookie_name'] . '_track'])) ? ((STRIP) ? stripslashes($_COOKIE[$config['cookie_name'] . '_track']) : $_COOKIE[$config['cookie_name'] . '_track']) : '';
			$tracking = ($tracking) ? tracking_unserialize($tracking) : array();

			foreach ($forum_id as $f_id)
			{
				$topic_ids36 = (isset($tracking['tf'][$f_id])) ? $tracking['tf'][$f_id] : array();

				if (isset($tracking['tf'][$f_id]))
				{
					unset($tracking['tf'][$f_id]);
				}

				foreach ($topic_ids36 as $topic_id36)
				{
					unset($tracking['t'][$topic_id36]);
				}

				if (isset($tracking['f'][$f_id]))
				{
					unset($tracking['f'][$f_id]);
				}

				$tracking['f'][$f_id] = base_convert(time() - $config['board_startdate'], 10, 36);
			}

			if (isset($tracking['tf']) && empty($tracking['tf']))
			{
				unset($tracking['tf']);
			}

			$user->set_cookie('track', tracking_serialize($tracking), time() + 31536000);
			$_COOKIE[$config['cookie_name'] . '_track'] = (STRIP) ? addslashes(tracking_serialize($tracking)) : tracking_serialize($tracking);

			unset($tracking);
		}

		return;
	}
	else if ($mode == 'topic')
	{
		if ($topic_id === false || $forum_id === false)
		{
			return;
		}

		if ($config['load_db_lastread'] && $user->data['is_registered'])
		{
			$sql = 'UPDATE ' . TOPICS_TRACK_TABLE . '
				SET mark_time = ' . (($post_time) ? $post_time : time()) . "
				WHERE user_id = {$user->data['user_id']}
					AND topic_id = $topic_id";
			$db->sql_query($sql);

			// insert row
			if (!$db->sql_affectedrows())
			{
				$db->sql_return_on_error(true);

				$sql_ary = array(
					'user_id'		=> (int) $user->data['user_id'],
					'topic_id'		=> (int) $topic_id,
					'forum_id'		=> (int) $forum_id,
					'mark_time'		=> ($post_time) ? (int) $post_time : time(),
				);

				$db->sql_query('INSERT INTO ' . TOPICS_TRACK_TABLE . ' ' . $db->sql_build_array('INSERT', $sql_ary));

				$db->sql_return_on_error(false);
			}
		}
		else if ($config['load_anon_lastread'] || $user->data['is_registered'])
		{
			$tracking = (isset($_COOKIE[$config['cookie_name'] . '_track'])) ? ((STRIP) ? stripslashes($_COOKIE[$config['cookie_name'] . '_track']) : $_COOKIE[$config['cookie_name'] . '_track']) : '';
			$tracking = ($tracking) ? tracking_unserialize($tracking) : array();

			$topic_id36 = base_convert($topic_id, 10, 36);

			if (!isset($tracking['t'][$topic_id36]))
			{
				$tracking['tf'][$forum_id][$topic_id36] = true;
			}

			$post_time = ($post_time) ? $post_time : time();
			$tracking['t'][$topic_id36] = base_convert($post_time - $config['board_startdate'], 10, 36);

			// If the cookie grows larger than 10000 characters we will remove the smallest value
			// This can result in old topics being unread - but most of the time it should be accurate...
			if (isset($_COOKIE[$config['cookie_name'] . '_track']) && strlen($_COOKIE[$config['cookie_name'] . '_track']) > 10000)
			{
				//echo 'Cookie grown too large' . print_r($tracking, true);

				// We get the ten most minimum stored time offsets and its associated topic ids
				$time_keys = array();
				for ($i = 0; $i < 10 && sizeof($tracking['t']); $i++)
				{
					$min_value = min($tracking['t']);
					$m_tkey = array_search($min_value, $tracking['t']);
					unset($tracking['t'][$m_tkey]);

					$time_keys[$m_tkey] = $min_value;
				}

				// Now remove the topic ids from the array...
				foreach ($tracking['tf'] as $f_id => $topic_id_ary)
				{
					foreach ($time_keys as $m_tkey => $min_value)
					{
						if (isset($topic_id_ary[$m_tkey]))
						{
							$tracking['f'][$f_id] = $min_value;
							unset($tracking['tf'][$f_id][$m_tkey]);
						}
					}
				}

				if ($user->data['is_registered'])
				{
					$user->data['user_lastmark'] = intval(base_convert(max($time_keys) + $config['board_startdate'], 36, 10));
					$db->sql_query('UPDATE ' . USERS_TABLE . ' SET user_lastmark = ' . $user->data['user_lastmark'] . " WHERE user_id = {$user->data['user_id']}");
				}
				else
				{
					$tracking['l'] = max($time_keys);
				}
			}

			$user->set_cookie('track', tracking_serialize($tracking), time() + 31536000);
			$_COOKIE[$config['cookie_name'] . '_track'] = (STRIP) ? addslashes(tracking_serialize($tracking)) : tracking_serialize($tracking);
		}

		return;
	}
	else if ($mode == 'post')
	{
		if ($topic_id === false)
		{
			return;
		}

		$use_user_id = (!$user_id) ? $user->data['user_id'] : $user_id;

		if ($config['load_db_track'] && $use_user_id != ANONYMOUS)
		{
			$db->sql_return_on_error(true);

			$sql_ary = array(
				'user_id'		=> (int) $use_user_id,
				'topic_id'		=> (int) $topic_id,
				'topic_posted'	=> 1
			);

			$db->sql_query('INSERT INTO ' . TOPICS_POSTED_TABLE . ' ' . $db->sql_build_array('INSERT', $sql_ary));

			$db->sql_return_on_error(false);
		}

		return;
	}
}

/**
* Get topic tracking info by using already fetched info
*/
function get_topic_tracking($forum_id, $topic_ids, &$rowset, $forum_mark_time, $global_announce_list = false)
{
	global $config, $user;

	$last_read = array();

	if (!is_array($topic_ids))
	{
		$topic_ids = array($topic_ids);
	}

	foreach ($topic_ids as $topic_id)
	{
		if (!empty($rowset[$topic_id]['mark_time']))
		{
			$last_read[$topic_id] = $rowset[$topic_id]['mark_time'];
		}
	}

	$topic_ids = array_diff($topic_ids, array_keys($last_read));

	if (sizeof($topic_ids))
	{
		$mark_time = array();

		// Get global announcement info
		if ($global_announce_list && sizeof($global_announce_list))
		{
			if (!isset($forum_mark_time[0]))
			{
				global $db;

				$sql = 'SELECT mark_time
					FROM ' . FORUMS_TRACK_TABLE . "
					WHERE user_id = {$user->data['user_id']}
						AND forum_id = 0";
				$result = $db->sql_query($sql);
				$row = $db->sql_fetchrow($result);
				$db->sql_freeresult($result);

				if ($row)
				{
					$mark_time[0] = $row['mark_time'];
				}
			}
			else
			{
				if ($forum_mark_time[0] !== false)
				{
					$mark_time[0] = $forum_mark_time[0];
				}
			}
		}

		if (!empty($forum_mark_time[$forum_id]) && $forum_mark_time[$forum_id] !== false)
		{
			$mark_time[$forum_id] = $forum_mark_time[$forum_id];
		}

		$user_lastmark = (isset($mark_time[$forum_id])) ? $mark_time[$forum_id] : $user->data['user_lastmark'];

		foreach ($topic_ids as $topic_id)
		{
			if ($global_announce_list && isset($global_announce_list[$topic_id]))
			{
				$last_read[$topic_id] = (isset($mark_time[0])) ? $mark_time[0] : $user_lastmark;
			}
			else
			{
				$last_read[$topic_id] = $user_lastmark;
			}
		}
	}

	return $last_read;
}

/**
* Get topic tracking info from db (for cookie based tracking only this function is used)
*/
function get_complete_topic_tracking($forum_id, $topic_ids, $global_announce_list = false)
{
	global $config, $user;

	$last_read = array();

	if (!is_array($topic_ids))
	{
		$topic_ids = array($topic_ids);
	}

	if ($config['load_db_lastread'] && $user->data['is_registered'])
	{
		global $db;

		$sql = 'SELECT topic_id, mark_time
			FROM ' . TOPICS_TRACK_TABLE . "
			WHERE user_id = {$user->data['user_id']}
				AND " . $db->sql_in_set('topic_id', $topic_ids);
		$result = $db->sql_query($sql);

		while ($row = $db->sql_fetchrow($result))
		{
			$last_read[$row['topic_id']] = $row['mark_time'];
		}
		$db->sql_freeresult($result);

		$topic_ids = array_diff($topic_ids, array_keys($last_read));

		if (sizeof($topic_ids))
		{
			$sql = 'SELECT forum_id, mark_time
				FROM ' . FORUMS_TRACK_TABLE . "
				WHERE user_id = {$user->data['user_id']}
					AND forum_id " .
					(($global_announce_list && sizeof($global_announce_list)) ? "IN (0, $forum_id)" : "= $forum_id");
			$result = $db->sql_query($sql);

			$mark_time = array();
			while ($row = $db->sql_fetchrow($result))
			{
				$mark_time[$row['forum_id']] = $row['mark_time'];
			}
			$db->sql_freeresult($result);

			$user_lastmark = (isset($mark_time[$forum_id])) ? $mark_time[$forum_id] : $user->data['user_lastmark'];

			foreach ($topic_ids as $topic_id)
			{
				if ($global_announce_list && isset($global_announce_list[$topic_id]))
				{
					$last_read[$topic_id] = (isset($mark_time[0])) ? $mark_time[0] : $user_lastmark;
				}
				else
				{
					$last_read[$topic_id] = $user_lastmark;
				}
			}
		}
	}
	else if ($config['load_anon_lastread'] || $user->data['is_registered'])
	{
		global $tracking_topics;

		if (!isset($tracking_topics) || !sizeof($tracking_topics))
		{
			$tracking_topics = (isset($_COOKIE[$config['cookie_name'] . '_track'])) ? ((STRIP) ? stripslashes($_COOKIE[$config['cookie_name'] . '_track']) : $_COOKIE[$config['cookie_name'] . '_track']) : '';
			$tracking_topics = ($tracking_topics) ? tracking_unserialize($tracking_topics) : array();
		}

		if (!$user->data['is_registered'])
		{
			$user_lastmark = (isset($tracking_topics['l'])) ? base_convert($tracking_topics['l'], 36, 10) + $config['board_startdate'] : 0;
		}
		else
		{
			$user_lastmark = $user->data['user_lastmark'];
		}

		foreach ($topic_ids as $topic_id)
		{
			$topic_id36 = base_convert($topic_id, 10, 36);

			if (isset($tracking_topics['t'][$topic_id36]))
			{
				$last_read[$topic_id] = base_convert($tracking_topics['t'][$topic_id36], 36, 10) + $config['board_startdate'];
			}
		}

		$topic_ids = array_diff($topic_ids, array_keys($last_read));

		if (sizeof($topic_ids))
		{
			$mark_time = array();
			if ($global_announce_list && sizeof($global_announce_list))
			{
				if (isset($tracking_topics['f'][0]))
				{
					$mark_time[0] = base_convert($tracking_topics['f'][0], 36, 10) + $config['board_startdate'];
				}
			}

			if (isset($tracking_topics['f'][$forum_id]))
			{
				$mark_time[$forum_id] = base_convert($tracking_topics['f'][$forum_id], 36, 10) + $config['board_startdate'];
			}

			$user_lastmark = (isset($mark_time[$forum_id])) ? $mark_time[$forum_id] : $user_lastmark;

			foreach ($topic_ids as $topic_id)
			{
				if ($global_announce_list && isset($global_announce_list[$topic_id]))
				{
					$last_read[$topic_id] = (isset($mark_time[0])) ? $mark_time[0] : $user_lastmark;
				}
				else
				{
					$last_read[$topic_id] = $user_lastmark;
				}
			}
		}
	}

	return $last_read;
}

/**
* Get list of unread topics
*
* @param int $user_id			User ID (or false for current user)
* @param string $sql_extra		Extra WHERE SQL statement
* @param string $sql_sort		ORDER BY SQL sorting statement
* @param string $sql_limit		Limits the size of unread topics list, 0 for unlimited query
* @param string $sql_limit_offset  Sets the offset of the first row to search, 0 to search from the start
*
* @return array[int][int]		Topic ids as keys, mark_time of topic as value
*/
function get_unread_topics($user_id = false, $sql_extra = '', $sql_sort = '', $sql_limit = 1001, $sql_limit_offset = 0)
{
	global $config, $db, $user;

	$user_id = ($user_id === false) ? (int) $user->data['user_id'] : (int) $user_id;

	// Data array we're going to return
	$unread_topics = array();

	if (empty($sql_sort))
	{
		$sql_sort = 'ORDER BY t.topic_last_post_time DESC';
	}

	if ($config['load_db_lastread'] && $user->data['is_registered'])
	{
		// Get list of the unread topics
		$last_mark = (int) $user->data['user_lastmark'];

		$sql_array = array(
			'SELECT'		=> 't.topic_id, t.topic_last_post_time, tt.mark_time as topic_mark_time, ft.mark_time as forum_mark_time',

			'FROM'			=> array(TOPICS_TABLE => 't'),

			'LEFT_JOIN'		=> array(
				array(
					'FROM'	=> array(TOPICS_TRACK_TABLE => 'tt'),
					'ON'	=> "tt.user_id = $user_id AND t.topic_id = tt.topic_id",
				),
				array(
					'FROM'	=> array(FORUMS_TRACK_TABLE => 'ft'),
					'ON'	=> "ft.user_id = $user_id AND t.forum_id = ft.forum_id",
				),
			),

			'WHERE'			=> "
				 t.topic_last_post_time > $last_mark AND
				(
				(tt.mark_time IS NOT NULL AND t.topic_last_post_time > tt.mark_time) OR
				(tt.mark_time IS NULL AND ft.mark_time IS NOT NULL AND t.topic_last_post_time > ft.mark_time) OR
				(tt.mark_time IS NULL AND ft.mark_time IS NULL)
				)
				$sql_extra
				$sql_sort",
		);

		$sql = $db->sql_build_query('SELECT', $sql_array);
		$result = $db->sql_query_limit($sql, $sql_limit, $sql_limit_offset);

		while ($row = $db->sql_fetchrow($result))
		{
			$topic_id = (int) $row['topic_id'];
			$unread_topics[$topic_id] = ($row['topic_mark_time']) ? (int) $row['topic_mark_time'] : (($row['forum_mark_time']) ? (int) $row['forum_mark_time'] : $last_mark);
		}
		$db->sql_freeresult($result);
	}
	else if ($config['load_anon_lastread'] || $user->data['is_registered'])
	{
		global $tracking_topics;

		if (empty($tracking_topics))
		{
			$tracking_topics = request_var($config['cookie_name'] . '_track', '', false, true);
			$tracking_topics = ($tracking_topics) ? tracking_unserialize($tracking_topics) : array();
		}

		if (!$user->data['is_registered'])
		{
			$user_lastmark = (isset($tracking_topics['l'])) ? base_convert($tracking_topics['l'], 36, 10) + $config['board_startdate'] : 0;
		}
		else
		{
			$user_lastmark = (int) $user->data['user_lastmark'];
		}

		$sql = 'SELECT t.topic_id, t.forum_id, t.topic_last_post_time
			FROM ' . TOPICS_TABLE . ' t
			WHERE t.topic_last_post_time > ' . $user_lastmark . "
			$sql_extra
			$sql_sort";
		$result = $db->sql_query_limit($sql, $sql_limit, $sql_limit_offset);

		while ($row = $db->sql_fetchrow($result))
		{
			$forum_id = (int) $row['forum_id'];
			$topic_id = (int) $row['topic_id'];
			$topic_id36 = base_convert($topic_id, 10, 36);

			if (isset($tracking_topics['t'][$topic_id36]))
			{
				$last_read = base_convert($tracking_topics['t'][$topic_id36], 36, 10) + $config['board_startdate'];

				if ($row['topic_last_post_time'] > $last_read)
				{
					$unread_topics[$topic_id] = $last_read;
				}
			}
			else if (isset($tracking_topics['f'][$forum_id]))
			{
				$mark_time = base_convert($tracking_topics['f'][$forum_id], 36, 10) + $config['board_startdate'];

				if ($row['topic_last_post_time'] > $mark_time)
				{
					$unread_topics[$topic_id] = $mark_time;
				}
			}
			else
			{
				$unread_topics[$topic_id] = $user_lastmark;
			}
		}
		$db->sql_freeresult($result);
	}

	return $unread_topics;
}

/**
* Check for read forums and update topic tracking info accordingly
*
* @param int $forum_id the forum id to check
* @param int $forum_last_post_time the forums last post time
* @param int $f_mark_time the forums last mark time if user is registered and load_db_lastread enabled
* @param int $mark_time_forum false if the mark time needs to be obtained, else the last users forum mark time
*
* @return true if complete forum got marked read, else false.
*/
function upd…