/station/forum/includes/functions.php

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<?php
/**
*
* @package phpBB3
* @version $Id: functions.php 9057 2008-11-10 16:24:18Z Kellanved $
* @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];
	}

	if (!isset($_REQUEST[$var_name]) || (is_array($_REQUEST[$var_name]) && !is_array($default)) || (is_array($default) && !is_array($_REQUEST[$var_name])))
	{
		return (is_array($default)) ? array() : $default;
	}

	$var = $_REQUEST[$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, $sub_key_type);
					set_var($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;
}

/**
* Set config value. Creates missing config entry.
*/
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');
	}
}

/**
* Generates an alphanumeric random string of given length
*/
function gen_rand_string($num_chars = 8)
{
	$rand_str = unique_id();
	$rand_str = str_replace('0', 'Z', strtoupper(base_convert($rand_str, 16, 35)));

	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', $config['rand_seed'], true);
		set_config('rand_seed_last_update', time(), true);
		$dss_seeded = true;
	}

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

/**
* Return formatted string for filesizes
*/
function get_formatted_filesize($bytes, $add_size_lang = true)
{
	global $user;

	if ($bytes >= pow(2, 20))
	{
		return ($add_size_lang) ? round($bytes / 1024 / 1024, 2) . ' ' . $user->lang['MIB'] : round($bytes / 1024 / 1024, 2);
	}

	if ($bytes >= pow(2, 10))
	{
		return ($add_size_lang) ? round($bytes / 1024, 2) . ' ' . $user->lang['KIB'] : round($bytes / 1024, 2);
	}

	return ($add_size_lang) ? ($bytes) . ' ' . $user->lang['BYTES'] : ($bytes);
}

/**
* 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)
{
	$itoa64 = './0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz';
	if (strlen($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$')
	{
		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;
}

/**
* 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 $filename The file/directory to be chmodded
* @param $perms Permissions to set
* @return true on success, otherwise false
*
* @author faw, phpBB Group
*/
function phpbb_chmod($filename, $perms = CHMOD_READ)
{
	// Return if the file no longer exists.
	if (!file_exists($filename))
	{
		return false;
	}

	if (!function_exists('fileowner') || !function_exists('filegroup'))
	{
		$file_uid = $file_gid = false;
		$common_php_owner = $common_php_group = 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);

		$file_uid = fileowner($filename);
		$file_gid = filegroup($filename);

		// Try to set the owner to the same common.php has
		if ($common_php_owner !== $file_uid && $common_php_owner !== false && $file_uid !== false)
		{
			// Will most likely not work
			if (@chown($filename, $common_php_owner));
			{
				$file_uid = fileowner($filename);
			}
		}

		// Try to set the group to the same common.php has
		if ($common_php_group !== $file_gid && $common_php_group !== false && $file_gid !== false)
		{
			if (@chgrp($filename, $common_php_group));
			{
				$file_gid = filegroup($filename);
			}
		}
	}

	// 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;

	// Who is PHP?
	if ($file_uid === false || $file_gid === false || $php_uid === false || $php_gids === false)
	{
		$php = null;
	}
	else if ($file_uid == $php_uid /* && $common_php_owner !== false && $common_php_owner === $file_uid*/)
	{
		$php = 'owner';
	}
	else if (in_array($file_gid, $php_gids))
	{
		$php = 'group';
	}
	else
	{
		$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 null:
		case 'owner':
			$result = @chmod($filename, ($owner << 6) + (0 << 3) + (0 << 0));

			if (!is_null($php) || (is_readable($filename) && is_writable($filename)))
			{
				break;
			}

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

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

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

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

		default:
			return false;
		break;
	}

	return $result;
}

// 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 ($path[0] == '/' || (DIRECTORY_SEPARATOR == '\\' && 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;
	}
}

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[] = $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;
}

/**
* 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 $mark_time_forum false if the mark time needs to be obtained, else the last users forum mark time
*
* @return true if complete forum got marked read, else false.
*/
function update_forum_tracking_info($forum_id, $forum_last_post_time, $f_mark_time = false, $mark_time_forum = false)
{
	global $db, $tracking_topics, $user, $config;

	// Determine the users last forum mark time if not given.
	if ($mark_time_forum === false)
	{
		if ($config['load_db_lastread'] && $user->data['is_registered'])
		{
			$mark_time_forum = (!empty($f_mark_time)) ? $f_mark_time : $user->data['user_lastmark'];
		}
		else if ($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();

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

			$mark_time_forum = (isset($tracking_topics['f'][$forum_id])) ? (int) (base_convert($tracking_topics['f'][$forum_id], 36, 10) + $config['board_startdate']) : $user->data['user_lastmark'];
		}
	}

	// Check the forum for any left unread topics.
	// If there are none, we mark the forum as read.
	if ($config['load_db_lastread'] && $user->data['is_registered'])
	{
		if ($mark_time_forum >= $forum_last_post_time)
		{
			// We do not need to mark read, this happened before. Therefore setting this to true
			$row = true;
		}
		else
		{
			$sql = 'SELECT t.forum_id FROM ' . TOPICS_TABLE . ' t
				LEFT JOIN ' . TOPICS_TRACK_TABLE . ' tt ON (tt.topic_id = t.topic_id AND tt.user_id = ' . $user->data['user_id'] . ')
				WHERE t.forum_id = ' . $forum_id . '
					AND t.topic_last_post_time > ' . $mark_time_forum . '
					AND t.topic_moved_id = 0
					AND (tt.topic_id IS NULL OR tt.mark_time < t.topic_last_post_time)
				GROUP BY t.forum_id';
			$result = $db->sql_query_limit($sql, 1);
			$row = $db->sql_fetchrow($result);
			$db->sql_freeresult($result);
		}
	}
	else if ($config['load_anon_lastread'] || $user->data['is_registered'])
	{
		// Get information from cookie
		$row = false;

		if (!isset($tracking_topics['tf'][$forum_id]))
		{
			// We do not need to mark read, this happened before. Therefore setting this to true
			$row = true;
		}
		else
		{
			$sql = 'SELECT topic_id
				FROM ' . TOPICS_TABLE . '
				WHERE forum_id = ' . $forum_id . '
					AND topic_last_post_time > ' . $mark_time_forum . '
					AND topic_moved_id = 0';
			$result = $db->sql_query($sql);

			$check_forum = $tracking_topics['tf'][$forum_id];
			$unread = false;

			while ($row = $db->sql_fetchrow($result))
			{
				if (!isset($check_forum[base_convert($row['topic_id'], 10, 36)]))
				{
					$unread = true;
					break;
				}
			}
			$db->sql_freeresult($result);

			$row = $unread;
		}
	}
	else
	{
		$row = true;
	}

	if (!$row)
	{
		markread('topics', $forum_id);
		return true;
	}

	return false;
}

/**
* Transform an array into a serialized format
*/
function tracking_serialize($input)
{
	$out = '';
	foreach ($input as $key => $value)
	{
		if (is_array($value))
		{
			$out .= $key . ':(' . tracking_serialize($value) . ');';
		}
		else
		{
			$out .= $key . ':' . $value . ';';
		}
	}
	return $out;
}

/**
* Transform a serialized array into an actual array
*/
function tracking_unserialize($string, $max_depth = 3)
{
	$n = strlen($string);
	if ($n > 10010)
	{
		die('Invalid data supplied');
	}
	$data = $stack = array();
	$key = '';
	$mode = 0;
	$level = &$data;
	for ($i = 0; $i < $n; ++$i)
	{
		switch ($mode)
		{
			case 0:
				switch ($string[$i])
				{
					case ':':
						$level[$key] = 0;
						$mode = 1;
					break;
					case ')':
						unset($level);
						$level = array_pop($stack);
						$mode = 3;
					break;
					default:
						$key .= $string[$i];
				}
			break;

			case 1:
				switch ($string[$i])
				{
					case '(':
						if (sizeof($stack) >= $max_depth)
						{
							die('Invalid data supplied');
						}
						$stack[] = &$level;
						$level[$key] = array();
						$level = &$level[$key];
						$key = '';
						$mode = 0;
					break;
					default:
						$level[$key] = $string[$i];
						$mode = 2;
					break;
				}
			break;

			case 2:
				switch ($string[$i])
				{
					case ')':
						unset($level);
						$level = array_pop($stack);
						$mode = 3;
					break;
					case ';':
						$key = '';
						$mode = 0;
					break;
					default:
						$level[$key] .= $string[$i];
					break;
				}
			break;

			case 3:
				switch ($string[$i])
				{
					case ')':
						unset($level);
						$level = array_pop($stack);
					break;
					case ';':
						$key = '';
						$mode = 0;
					break;
					default:
						die('Invalid data supplied');
					break;
				}
			break;
		}
	}

	if (sizeof($stack) != 0 || ($mode != 0 && $mode != 3))
	{
		die('Invalid data supplied');
	}

	return $level;
}

// Pagination functions

/**
* Pagination routine, generates page number sequence
* tpl_prefix is for using different pagination blocks at one page
*/
function generate_pagination($base_url, $num_items, $per_page, $start_item, $add_prevnext_text = false, $tpl_prefix = '')
{
	global $template, $user;

	// Make sure $per_page is a valid value
	$per_page = ($per_page <= 0) ? 1 : $per_page;

	$seperator = '<span class="page-sep">' . $user->lang['COMMA_SEPARATOR'] . '</span>';
	$total_pages = ceil($num_items / $per_page);

	if ($total_pages == 1 || !$num_items)
	{
		return false;
	}

	$on_page = floor($start_item / $per_page) + 1;
	$url_delim = (strpos($base_url, '?') === false) ? '?' : '&amp;';

	$page_string = ($on_page == 1) ? '<strong>1</strong>' : '<a href="' . $base_url . '">1</a>';

	if ($total_pages > 5)
	{
		$start_cnt = min(max(1, $on_page - 4), $total_pages - 5);
		$end_cnt = max(min($total_pages, $on_page + 4), 6);

		$page_string .= ($start_cnt > 1) ? ' ... ' : $seperator;

		for ($i = $start_cnt + 1; $i < $end_cnt; $i++)
		{
			$page_string .= ($i == $on_page) ? '<strong>' . $i . '</strong>' : '<a href="' . $base_url . "{$url_delim}start=" . (($i - 1) * $per_page) . '">' . $i . '</a>';
			if ($i < $end_cnt - 1)
			{
				$page_string .= $seperator;
			}
		}

		$page_string .= ($end_cnt < $total_pages) ? ' ... ' : $seperator;
	}
	else
	{
		$page_string .= $seperator;

		for ($i = 2; $i < $total_pages; $i++)
		{
			$page_string .= ($i == $on_page) ? '<strong>' . $i . '</strong>' : '<a href="' . $base_url . "{$url_delim}start=" . (($i - 1) * $per_page) . '">' . $i . '</a>';
			if ($i < $total_pages)
			{
				$page_string .= $seperator;
			}
		}
	}

	$page_string .= ($on_page == $total_pages) ? '<strong>' . $total_pages . '</strong>' : '<a href="' . $base_url . "{$url_delim}start=" . (($total_pages - 1) * $per_page) . '">' . $total_pages . '</a>';

	if ($add_prevnext_text)
	{
		if ($on_page != 1)
		{
			$page_string = '<a href="' . $base_url . "{$url_delim}start=" . (($on_page - 2) * $per_page) . '">' . $user->lang['PREVIOUS'] . '</a>&nbsp;&nbsp;' . $page_string;
		}

		if ($on_page != $total_pages)
		{
			$page_string .= '&nbsp;&nbsp;<a href="' . $base_url . "{$url_delim}start=" . ($on_page * $per_page) . '">' . $user->lang['NEXT'] . '</a>';
		}
	}

	$template->assign_vars(array(
		$tpl_prefix . 'BASE_URL'		=> $base_url,
		'A_' . $tpl_prefix . 'BASE_URL'	=> addslashes($base_url),
		$tpl_prefix . 'PER_PAGE'		=> $per_page,

		$tpl_prefix . 'PREVIOUS_PAGE'	=> ($on_page == 1) ? '' : $base_url . "{$url_delim}start=" . (($on_page - 2) * $per_page),
		$tpl_prefix . 'NEXT_PAGE'		=> ($on_page == $total_pages) ? '' : $base_url . "{$url_delim}start=" . ($on_page * $per_page),
		$tpl_prefix . 'TOTAL_PAGES'		=> $total_pages,
	));

	return $page_string;
}

/**
* Return current page (pagination)
*/
function on_page($num_items, $per_page, $start)
{
	global $template, $user;

	// Make sure $per_page is a valid value
	$per_page = ($per_page <= 0) ? 1 : $per_page;

	$on_page = floor($start / $per_page) + 1;

	$template->assign_vars(array(
		'ON_PAGE'		=> $on_page)
	);

	return sprintf($user->lang['PAGE_OF'], $on_page, max(ceil($num_items / $per_page), 1));
}

// Server functions (building urls, redirecting...)

/**
* Append session id to url.
* This function supports hooks.
*
* @param string $url The url the session id needs to be appended to (can have params)
* @param mixed $params String or array of additional url parameters
* @param bool $is_amp Is url using &amp; (true) or & (false)
* @param string $session_id Possibility to use a custom session id instead of the global one
*
* Examples:
* <code>
* append_sid("{$phpbb_root_path}viewtopic.$phpEx?t=1&amp;f=2");
* append_sid("{$phpbb_root_path}viewtopic.$phpEx", 't=1&amp;f=2');
* append_sid("{$phpbb_root_path}viewtopic.$phpEx", 't=1&f=2', false);
* append_sid("{$phpbb_root_path}viewtopic.$phpEx", array('t' => 1, 'f' => 2));
* </code>
*
*/
function append_sid($url, $params = false, $is_amp = true, $session_id = false)
{
	global $_SID, $_EXTRA_URL, $phpbb_hook;

	// Developers using the hook function need to globalise the $_SID and $_EXTRA_URL on their own and also handle it appropiatly.
	// They could mimick most of what is within this function
	if (!empty($phpbb_hook) && $phpbb_hook->call_hook(__FUNCTION__, $url, $params, $is_amp, $session_id))
	{
		if ($phpbb_hook->hook_return(__FUNCTION__))
		{
			return $phpbb_hook->hook_return_result(__FUNCTION__);
		}
	}

	// Assign sid if session id is not specified
	if ($session_id === false)
	{
		$session_id = $_SID;
	}

	$amp_delim = ($is_amp) ? '&amp;' : '&';
	$url_delim = (strpos($url, '?') === false) ? '?' : $amp_delim;

	// Appending custom url parameter?
	$append_url = (!empty($_EXTRA_URL)) ? implode($amp_delim, $_EXTRA_URL) : '';

	$anchor = '';
	if (strpos($url, '#') !== false)
	{
		list($url, $anchor) = explode('#', $url, 2);
		$anchor = '#' . $anchor;
	}
	else if (!is_array($params) && strpos($params, '#') !== false)
	{
		list($params, $anchor) = explode('#', $params, 2);
		$anchor = '#' . $anchor;
	}

	// Use the short variant if possible ;)
	if ($params === false)
	{
		// Append session id
		if (!$session_id)
		{
			return $url . (($append_url) ? $url_delim . $append_url : '') . $anchor;
		}
		else
		{
			return $url . (($append_url) ? $url_delim . $append_url . $amp_delim : $url_delim) . 'sid=' . $session_id . $anchor;
		}
	}

	// Build string if parameters are specified as array
	if (is_array($params))
	{
		$output = array();

		foreach ($params as $key => $item)
		{
			if ($item === NULL)
			{
				continue;
			}

			if ($key == '#')
			{
				$anchor = '#' . $item;
				continue;
			}

			$output[] = $key . '=' . $item;
		}

		$params = implode($amp_delim, $output);
	}

	// Append session id and parameters (even if they are empty)
	// If parameters are empty, the developer can still append his/her parameters without caring about the delimiter
	return $url . (($append_url) ? $url_delim . $append_url . $amp_delim : $url_delim) . $params . ((!$session_id) ? '' : $amp_delim . 'sid=' . $session_id) . $anchor;
}

/**
* Generate board url (example: http://www.example.com/phpBB)
* @param bool $without_script_path if set to true the script path gets not appended (example: http://www.example.com)
*/
function generate_board_url($without_script_path = false)
{
	global $config, $user;

	$server_name = $user->host;
	$server_port = (!empty($_SERVER['SERVER_PORT'])) ? (int) $_SERVER['SERVER_PORT'] : (int) getenv('SERVER_PORT');

	// Forcing server vars is the only way to specify/override the protocol
	if ($config['force_server_vars'] || !$server_name)
	{
		$server_protocol = ($config['server_protocol']) ? $config['server_protocol'] : (($config['cookie_secure']) ? 'https://' : 'http://');
		$server_name = $config['server_name'];
		$server_port = (int) $config['server_port'];
		$script_path = $config['script_path'];

		$url = $server_protocol . $server_name;
		$cookie_secure = $config['cookie_secure'];
	}
	else
	{
		// Do not rely on cookie_secure, users seem to think that it means a secured cookie instead of an encrypted connection
		$cookie_secure = (isset($_SERVER['HTTPS']) && $_SERVER['HTTPS'] == 'on') ? 1 : 0;
		$url = (($cookie_secure) ? 'https://' : 'http://') . $server_name;

		$script_path = $user->page['root_script_path'];
	}

	if ($server_port && (($cookie_secure && $server_port <> 443) || (!$cookie_secure && $server_port <> 80)))
	{
		// HTTP HOST can carry a port number (we fetch $user->host, b…