<?php
/**
*
* @package phpBB3
* @version $Id: template.php 8943 2008-09-26 13:09:56Z acydburn $
* @copyright (c) 2005 phpBB Group, sections (c) 2001 ispi of Lincoln Inc
* @license http://opensource.org/licenses/gpl-license.php GNU Public License
*
*/

/**
* Base Template class.
* @package phpBB3
*/
class Template
{
	/** variable that holds all the data we'll be substituting into
	* the compiled templates. Takes form:
	* --> $this->_tpldata[block][iteration#][child][iteration#][child2][iteration#][variablename] == value
	* if it's a root-level variable, it'll be like this:
	* --> $this->_tpldata[.][0][varname] == value
	*/
	private $_tpldata = array('.' => array(0 => array()));
	private $_rootref;

	// Root dir and hash of filenames for each template handle.
	private $root = '';
	private $cachepath = '';
	private $files = array();
	private $filename = array();
	//private $files_inherit = array();
	//private $files_template = array();
	//private $inherit_root = '';

	// this will hash handle names to the compiled/uncompiled code for that handle.
	private $compiled_code = array();
	
	// Various storage arrays(functions_template)
	private $block_names = array();
	private $block_else_level = array();
	
	// ***** addon *******
	private $lang = NULL;
	const PHPEX = 'php';
	
	
	/**
	* Set template location
	* @access public
	*/
	public function __construct($template_path='template', $cache_path='cache', &$lang=NULL)
	{
		if (file_exists($template_path))
		{
			$this->root = $template_path;
			$this->cachepath = $cache_path . '/tpl_';
			$this->lang = &$lang;
		}
		else
			trigger_error('Template path could not be found: ' . $template_path, E_USER_ERROR);

		$this->_rootref = &$this->_tpldata['.'][0];
	}

	/**
	* Set custom template location (able to use directory outside of phpBB)
	* @access public
	*/
	function set_custom_template($template_path, $cache_path)
	{
		$this->root = $template_path;
		$this->cachepath = $cache_path . '/tpl_';

		return true;
	}
	
	/**
	* addon
	* Set custom language variable
	* @access public
	*/
	function set_language_var(&$lang)
	{
		$this->lang = &$lang;
	}
	
	/**
	* Sets the template filenames for handles. $filename_array
	* should be a hash of handle => filename pairs.
	* @access public
	*/
	public function set_filenames($filename_array)
	{
		if (!is_array($filename_array))
			return false;
		
		foreach ($filename_array as $handle => $filename)
		{
			if (empty($filename))
				trigger_error("template->set_filenames: Empty filename specified for $handle", E_USER_ERROR);
			
			$this->filename[$handle] = $filename;
			$this->files[$handle] = $this->root . '/' . $filename;			
		}
		
		return true;
	}

	/**
	* Destroy template data set
	* @access public
	*/
	public function destroy()
	{
		$this->_tpldata = array('.' => array(0 => array()));
	}

	/**
	* Reset/empty complete block
	* @access public
	*/
	public function destroy_block_vars($blockname)
	{
		if (strpos($blockname, '.') !== false)
		{
			// Nested block.
			$blocks = explode('.', $blockname);
			$blockcount = sizeof($blocks) - 1;

			$str = &$this->_tpldata;
			for ($i = 0; $i < $blockcount; $i++)
			{
				$str = &$str[$blocks[$i]];
				$str = &$str[sizeof($str) - 1];
			}

			unset($str[$blocks[$blockcount]]);
		}
		else
		{
			// Top-level block.
			unset($this->_tpldata[$blockname]);
		}

		return true;
	}

	/**
	* Display handle
	* @access public
	*/
	public function display($handle, $include_once = true)
	{
		if ($filename = $this->_tpl_load($handle))
			($include_once) ? include_once($filename) : include($filename);
		else
			eval(' ?>' . $this->compiled_code[$handle] . '<?php ');

		return true;
	}

	/**
	* Display the handle and assign the output to a template variable or return the compiled result.
	* @access public
	*/
	public function assign_display($handle, $template_var = '', $return_content = true, $include_once = false)
	{
		ob_start();
		$this->display($handle, $include_once);
		$contents = ob_get_clean();

		if ($return_content)
			return $contents;

		$this->assign_var($template_var, $contents);

		return true;
	}
	
	/**
	* Load a compiled template if possible, if not, recompile it
	* @access private
	*/
	private function _tpl_load(&$handle)
	{
		$filename = $this->cachepath . str_replace('/', '.', $this->filename[$handle]) . '.' . self::PHPEX;
		
		if (!file_exists($filename) || @filesize($filename) === 0)
			$recompile = true;
		else
			$recompile = (@filemtime($filename) < filemtime($this->files[$handle])) ? true : false;
				
		// Recompile page if the original template is newer, otherwise load the compiled version
		if (!$recompile)
			return $filename;

		// If we don't have a file assigned to this handle, die.
		if (!isset($this->files[$handle]))
			trigger_error("template->_tpl_load(): No file specified for handle $handle", E_USER_ERROR);

		$this->_tpl_load_file($handle);
		return false;
	}

	/**
	* Assign key variable pairs from an array
	* @access public
	*/
	public function assign_vars($vararray)
	{
		foreach ($vararray as $key => $val)
			$this->_rootref[$key] = $val;

		return true;
	}

	/**
	* Assign a single variable to a single key
	* @access public
	*/
	public function assign_var($varname, $varval)
	{
		$this->_rootref[$varname] = $varval;

		return true;
	}

	/**
	* Assign key variable pairs from an array to a specified block
	* @access public
	*/
	public function assign_block_vars($blockname, $vararray)
	{
		if (strpos($blockname, '.') !== false)
		{
			// Nested block.
			$blocks = explode('.', $blockname);
			$blockcount = sizeof($blocks) - 1;

			$str = &$this->_tpldata;
			for ($i = 0; $i < $blockcount; $i++)
			{
				$str = &$str[$blocks[$i]];
				if (!empty($str)) {
                    $str = &$str[sizeof($str) - 1];
                }
			}

			$s_row_count = isset($str[$blocks[$blockcount]]) ? sizeof($str[$blocks[$blockcount]]) : 0;
			$vararray['S_ROW_COUNT'] = $s_row_count;

			// Assign S_FIRST_ROW
			if (!$s_row_count)
				$vararray['S_FIRST_ROW'] = true;

			// Now the tricky part, we always assign S_LAST_ROW and remove the entry before
			// This is much more clever than going through the complete template data on display (phew)
			$vararray['S_LAST_ROW'] = true;
			if ($s_row_count > 0)
				unset($str[$blocks[$blockcount]][($s_row_count - 1)]['S_LAST_ROW']);

			// Now we add the block that we're actually assigning to.
			// We're adding a new iteration to this block with the given
			// variable assignments.
			$str[$blocks[$blockcount]][] = $vararray;
		}
		else
		{
			// Top-level block.
			$s_row_count = (isset($this->_tpldata[$blockname])) ? sizeof($this->_tpldata[$blockname]) : 0;
			$vararray['S_ROW_COUNT'] = $s_row_count;

			// Assign S_FIRST_ROW
			if (!$s_row_count)
				$vararray['S_FIRST_ROW'] = true;

			// We always assign S_LAST_ROW and remove the entry before
			$vararray['S_LAST_ROW'] = true;
			if ($s_row_count > 0)
				unset($this->_tpldata[$blockname][($s_row_count - 1)]['S_LAST_ROW']);
			
			// Add a new iteration to this block with the variable assignments we were given.
			$this->_tpldata[$blockname][] = $vararray;
		}

		return true;
	}

	/**
	* Change already assigned key variable pair (one-dimensional - single loop entry)
	*
	* An example of how to use this function:
	* {@example alter_block_array.php}
	*
	* @param	string	$blockname	the blockname, for example 'loop'
	* @param	array	$vararray	the var array to insert/add or merge
	* @param	mixed	$key		Key to search for
	*
	* array: KEY => VALUE [the key/value pair to search for within the loop to determine the correct position]
	*
	* int: Position [the position to change or insert at directly given]
	*
	* If key is false the position is set to 0
	* If key is true the position is set to the last entry
	*
	* @param	string	$mode		Mode to execute (valid modes are 'insert' and 'change')
	*
	*	If insert, the vararray is inserted at the given position (position counting from zero).
	*	If change, the current block gets merged with the vararray (resulting in new key/value pairs be added and existing keys be replaced by the new value).
	*
	* Since counting begins by zero, inserting at the last position will result in this array: array(vararray, last positioned array)
	* and inserting at position 1 will result in this array: array(first positioned array, vararray, following vars)
	*
	* @return bool false on error, true on success
	* @access public
	*/
	public function alter_block_array($blockname, $vararray, $key = false, $mode = 'insert')
	{
		if (strpos($blockname, '.') !== false)
		{
			// Nested blocks are not supported
			return false;
		}
		
		// Change key to zero (change first position) if false and to last position if true
		if ($key === false || $key === true)
		{
			$key = ($key === false) ? 0 : sizeof($this->_tpldata[$blockname]);
		}

		// Get correct position if array given
		if (is_array($key))
		{
			// Search array to get correct position
			list($search_key, $search_value) = @each($key);

			$key = NULL;
			foreach ($this->_tpldata[$blockname] as $i => $val_ary)
			{
				if ($val_ary[$search_key] === $search_value)
				{
					$key = $i;
					break;
				}
			}

			// key/value pair not found
			if ($key === NULL)
				return false;
		}

		// Insert Block
		if ($mode == 'insert')
		{
			// Make sure we are not exceeding the last iteration
			if ($key >= sizeof($this->_tpldata[$blockname]))
			{
				$key = sizeof($this->_tpldata[$blockname]);
				unset($this->_tpldata[$blockname][($key - 1)]['S_LAST_ROW']);
				$vararray['S_LAST_ROW'] = true;
			}
			else if ($key === 0)
			{
				unset($this->_tpldata[$blockname][0]['S_FIRST_ROW']);
				$vararray['S_FIRST_ROW'] = true;
			}

			// Re-position template blocks
			for ($i = sizeof($this->_tpldata[$blockname]); $i > $key; $i--)
			{
				$this->_tpldata[$blockname][$i] = $this->_tpldata[$blockname][$i-1];
				$this->_tpldata[$blockname][$i]['S_ROW_COUNT'] = $i;
			}

			// Insert vararray at given position
			$vararray['S_ROW_COUNT'] = $key;
			$this->_tpldata[$blockname][$key] = $vararray;

			return true;
		}

		// Which block to change?
		if ($mode == 'change')
		{
			if ($key == sizeof($this->_tpldata[$blockname]))
			{
				$key--;
			}

			$this->_tpldata[$blockname][$key] = array_merge($this->_tpldata[$blockname][$key], $vararray);
			return true;
		}

		return false;
	}

	/**
	* Include a separate template
	* @access private
	*/
	private function _tpl_include($filename, $include = true)
	{
		$handle = $filename;
		$this->filename[$handle] = $filename;
		$this->files[$handle] = $this->root . '/' . $filename;		

		$filename = $this->_tpl_load($handle);

		if ($include)
		{
			if ($filename)
			{
				include($filename);
				return;
			}
			eval(' ?>' . $this->compiled_code[$handle] . '<?php ');
		}
	}
	
	/*-------------------- FUNCTIONS_TEMPLATE ---------------------------------*/
	/**
	* Load template source from file
	* @access private
	*/
	private function _tpl_load_file($handle, $store_in_db = false)
	{
		// Try and open template for read
		if (!file_exists($this->files[$handle]))
			trigger_error("template->_tpl_load_file(): File {$this->files[$handle]} does not exist or is empty", E_USER_ERROR);

		$this->compiled_code[$handle] = $this->compile(trim(@file_get_contents($this->files[$handle])));

		// Actually compile the code now.
		$this->compile_write($handle, $this->compiled_code[$handle]);
	}
	
	/**
	* Remove any PHP tags that do not belong, these regular expressions are derived from
	* the ones that exist in zend_language_scanner.l
	* @access private
	*/
	private function remove_php_tags(&$code)
	{
		// This matches the information gathered from the internal PHP lexer
		$match = array(
			'#<([\?%])=?.*?\1>#s',
			'#<script\s+language\s*=\s*(["\']?)php\1\s*>.*?</script\s*>#s',
			'#<\?php(?:\r\n?|[ \n\t]).*?\?>#s'
		);

		$code = preg_replace($match, '', $code);
	}
	
	/**
	* The all seeing all doing compile method. Parts are inspired by or directly from Smarty
	* @access private
	*/
	private function compile($code, $no_echo = false, $echo_var = '')
	{
		if ($echo_var)
			global $$echo_var;

		// Remove any "loose" php ... we want to give admins the ability
		// to switch on/off PHP for a given template. Allowing unchecked
		// php is a no-no. There is a potential issue here in that non-php
		// content may be removed ... however designers should use entities
		// if they wish to display < and >
		$this->remove_php_tags($code);

		// Pull out all block/statement level elements and separate plain text
		preg_match_all('#<!-- PHP -->(.*?)<!-- ENDPHP -->#s', $code, $matches);
		$php_blocks = $matches[1];
		$code = preg_replace('#<!-- PHP -->.*?<!-- ENDPHP -->#s', '<!-- PHP -->', $code);

		preg_match_all('#<!-- INCLUDE ([a-zA-Z0-9\_\-\+\./]+) -->#', $code, $matches);
		$include_blocks = $matches[1];
		$code = preg_replace('#<!-- INCLUDE [a-zA-Z0-9\_\-\+\./]+ -->#', '<!-- INCLUDE -->', $code);

		preg_match_all('#<!-- INCLUDEPHP ([a-zA-Z0-9\_\-\+\./]+) -->#', $code, $matches);
		$includephp_blocks = $matches[1];
		$code = preg_replace('#<!-- INCLUDEPHP [a-zA-Z0-9\_\-\+\./]+ -->#', '<!-- INCLUDEPHP -->', $code);

		preg_match_all('#<!-- ([^<].*?) (.*?)? ?-->#', $code, $blocks, PREG_SET_ORDER);

		$text_blocks = preg_split('#<!-- [^<].*? (?:.*?)? ?-->#', $code);

		for ($i = 0, $j = sizeof($text_blocks); $i < $j; $i++)
		{
			$this->compile_var_tags($text_blocks[$i]);
		}
		$compile_blocks = array();

		for ($curr_tb = 0, $tb_size = sizeof($blocks); $curr_tb < $tb_size; $curr_tb++)
		{
			$block_val = &$blocks[$curr_tb];

			switch ($block_val[1])
			{
				case 'BEGIN':
					$this->block_else_level[] = false;
					$compile_blocks[] = '<?php ' . $this->compile_tag_block($block_val[2]) . ' ?>';
				break;

				case 'BEGINELSE':
					$this->block_else_level[sizeof($this->block_else_level) - 1] = true;
					$compile_blocks[] = '<?php }} else { ?>';
				break;

				case 'END':
					array_pop($this->block_names);
					$compile_blocks[] = '<?php ' . ((array_pop($this->block_else_level)) ? '}' : '}}') . ' ?>';
				break;

				case 'IF':
					$compile_blocks[] = '<?php ' . $this->compile_tag_if($block_val[2], false) . ' ?>';
				break;

				case 'ELSE':
					$compile_blocks[] = '<?php } else { ?>';
				break;

				case 'ELSEIF':
					$compile_blocks[] = '<?php ' . $this->compile_tag_if($block_val[2], true) . ' ?>';
				break;

				case 'ENDIF':
					$compile_blocks[] = '<?php } ?>';
				break;

				case 'DEFINE':
					$compile_blocks[] = '<?php ' . $this->compile_tag_define($block_val[2], true) . ' ?>';
				break;

				case 'UNDEFINE':
					$compile_blocks[] = '<?php ' . $this->compile_tag_define($block_val[2], false) . ' ?>';
				break;

				case 'INCLUDE':
					$temp = array_shift($include_blocks);
					$compile_blocks[] = '<?php ' . $this->compile_tag_include($temp) . ' ?>';
					$this->_tpl_include($temp, false);
				break;

				case 'INCLUDEPHP':
					$compile_blocks[] = ($config['tpl_allow_php']) ? '<?php ' . $this->compile_tag_include_php(array_shift($includephp_blocks)) . ' ?>' : '';
				break;

				case 'PHP':
					$compile_blocks[] = ($config['tpl_allow_php']) ? '<?php ' . array_shift($php_blocks) . ' ?>' : '';
				break;

				default:
					$this->compile_var_tags($block_val[0]);
					$trim_check = trim($block_val[0]);
					$compile_blocks[] = (!$no_echo) ? ((!empty($trim_check)) ? $block_val[0] : '') : ((!empty($trim_check)) ? $block_val[0] : '');
				break;
			}
		}

		$template_php = '';
		for ($i = 0, $size = sizeof($text_blocks); $i < $size; $i++)
		{
			$trim_check_text = trim($text_blocks[$i]);
			$template_php .= (!$no_echo) ? (($trim_check_text != '') ? $text_blocks[$i] : '') . ((isset($compile_blocks[$i])) ? $compile_blocks[$i] : '') : (($trim_check_text != '') ? $text_blocks[$i] : '') . ((isset($compile_blocks[$i])) ? $compile_blocks[$i] : '');
		}

		// There will be a number of occasions where we switch into and out of
		// PHP mode instantaneously. Rather than "burden" the parser with this
		// we'll strip out such occurences, minimising such switching
		$template_php = str_replace(' ?><?php ', ' ', $template_php);

		return (!$no_echo) ? $template_php : "\$$echo_var .= '" . $template_php . "'";
	}
	
	/**
	* Compile variables
	* @access private
	*/
	private function compile_var_tags(&$text_blocks)
	{
		// change template varrefs into PHP varrefs
		$varrefs = array();

		// This one will handle varrefs WITH namespaces
		preg_match_all('#\{((?:[a-z0-9\-_]+\.)+)(\$)?([A-Z0-9\-_]+)\}#', $text_blocks, $varrefs, PREG_SET_ORDER);

		foreach ($varrefs as $var_val)
		{
			$namespace = $var_val[1];
			$varname = $var_val[3];
			$new = $this->generate_block_varref($namespace, $varname, true, $var_val[2]);

			$text_blocks = str_replace($var_val[0], $new, $text_blocks);
		}

		// This will handle the remaining root-level varrefs
		// transform vars prefixed by L_ into their language variable pendant if nothing is set within the tpldata array
		if (strpos($text_blocks, '{L_') !== false)
		{
			$text_blocks = preg_replace('#\{L_([a-z0-9\-_]*)\}#is', "<?php echo ((isset(\$this->_rootref['L_\\1'])) ? \$this->_rootref['L_\\1'] : ((isset(\$this->lang['\\1'])) ? \$this->lang['\\1'] : '{ \\1 }')); ?>", $text_blocks);
		}
		
		// Handle addslashed language variables prefixed with LA_
		// If a template variable already exist, it will be used in favor of it...
		if (strpos($text_blocks, '{LA_') !== false)
		{
			$text_blocks = preg_replace('#\{LA_([a-z0-9\-_]*)\}#is', "<?php echo ((isset(\$this->_rootref['LA_\\1'])) ? \$this->_rootref['LA_\\1'] : ((isset(\$this->_rootref['L_\\1'])) ? addslashes(\$this->_rootref['L_\\1']) : ((isset(\$this->lang['\\1'])) ? addslashes(\$this->lang['\\1']) : '{ \\1 }'))); ?>", $text_blocks);
		}

		// Handle remaining varrefs
		$text_blocks = preg_replace('#\{([a-z0-9\-_]+)\}#is', "<?php echo (isset(\$this->_rootref['\\1'])) ? \$this->_rootref['\\1'] : ''; ?>", $text_blocks);
		$text_blocks = preg_replace('#\{\$([a-z0-9\-_]+)\}#is', "<?php echo (isset(\$this->_tpldata['DEFINE']['.']['\\1'])) ? \$this->_tpldata['DEFINE']['.']['\\1'] : ''; ?>", $text_blocks);

		return;
	}
	
	/**
	* Compile blocks
	* @access private
	*/
	private function compile_tag_block($tag_args)
	{
		$no_nesting = false;

		// Is the designer wanting to call another loop in a loop?
		if (strpos($tag_args, '!') === 0)
		{
			// Count the number if ! occurrences (not allowed in vars)
			$no_nesting = substr_count($tag_args, '!');
			$tag_args = substr($tag_args, $no_nesting);
		}

		// Allow for control of looping (indexes start from zero):
		// foo(2)    : Will start the loop on the 3rd entry
		// foo(-2)   : Will start the loop two entries from the end
		// foo(3,4)  : Will start the loop on the fourth entry and end it on the fifth
		// foo(3,-4) : Will start the loop on the fourth entry and end it four from last
		if (preg_match('#^([^()]*)\(([\-\d]+)(?:,([\-\d]+))?\)$#', $tag_args, $match))
		{
			$tag_args = $match[1];

			if ($match[2] < 0)
				$loop_start = '($_' . $tag_args . '_count ' . $match[2] . ' < 0 ? 0 : $_' . $tag_args . '_count ' . $match[2] . ')';
			else
				$loop_start = '($_' . $tag_args . '_count < ' . $match[2] . ' ? $_' . $tag_args . '_count : ' . $match[2] . ')';

			if (strlen($match[3]) < 1 || $match[3] == -1)
				$loop_end = '$_' . $tag_args . '_count';
			else if ($match[3] >= 0)
				$loop_end = '(' . ($match[3] + 1) . ' > $_' . $tag_args . '_count ? $_' . $tag_args . '_count : ' . ($match[3] + 1) . ')';
			else //if ($match[3] < -1)
				$loop_end = '$_' . $tag_args . '_count' . ($match[3] + 1);
		}
		else
		{
			$loop_start = 0;
			$loop_end = '$_' . $tag_args . '_count';
		}

		$tag_template_php = '';
		array_push($this->block_names, $tag_args);

		if ($no_nesting !== false)
		{
			// We need to implode $no_nesting times from the end...
			$block = array_slice($this->block_names, -$no_nesting);
		}
		else
		{
			$block = $this->block_names;
		}

		if (sizeof($block) < 2)
		{
			// Block is not nested.
			$tag_template_php = '$_' . $tag_args . "_count = (isset(\$this->_tpldata['$tag_args'])) ? sizeof(\$this->_tpldata['$tag_args']) : 0;";
			$varref = "\$this->_tpldata['$tag_args']";
		}
		else
		{
			// This block is nested.
			// Generate a namespace string for this block.
			$namespace = implode('.', $block);

			// Get a reference to the data array for this block that depends on the
			// current indices of all parent blocks.
			$varref = $this->generate_block_data_ref($namespace, false);

			// Create the for loop code to iterate over this block.
			$tag_template_php = '$_' . $tag_args . '_count = (isset(' . $varref . ')) ? sizeof(' . $varref . ') : 0;';
		}

		$tag_template_php .= 'if ($_' . $tag_args . '_count) {';
		$tag_template_php .= 'for ($_' . $tag_args . '_i = ' . $loop_start . '; $_' . $tag_args . '_i < ' . $loop_end . '; ++$_' . $tag_args . '_i){';
		$tag_template_php .= '$_'. $tag_args . '_val = &' . $varref . '[$_'. $tag_args. '_i];';

		return $tag_template_php;
	}
	
	/**
	* Compile IF tags - much of this is from Smarty with
	* some adaptions for our block level methods
	* @access private
	*/
	private function compile_tag_if($tag_args, $elseif)
	{
		// Tokenize args for 'if' tag.
		preg_match_all('/(?:
			"[^"\\\\]*(?:\\\\.[^"\\\\]*)*"         |
			\'[^\'\\\\]*(?:\\\\.[^\'\\\\]*)*\'     |
			[(),]                                  |
			[^\s(),]+)/x', $tag_args, $match);

		$tokens = $match[0];
		$is_arg_stack = array();

		for ($i = 0, $size = sizeof($tokens); $i < $size; $i++)
		{
			$token = &$tokens[$i];

			switch ($token)
			{
				case '!==':
				case '===':
				case '<<':
				case '>>':
				case '|':
				case '^':
				case '&':
				case '~':
				case ')':
				case ',':
				case '+':
				case '-':
				case '*':
				case '/':
				case '@':
				break;

				case '==':
				case 'eq':
					$token = '==';
				break;

				case '!=':
				case '<>':
				case 'ne':
				case 'neq':
					$token = '!=';
				break;

				case '<':
				case 'lt':
					$token = '<';
				break;

				case '<=':
				case 'le':
				case 'lte':
					$token = '<=';
				break;

				case '>':
				case 'gt':
					$token = '>';
				break;

				case '>=':
				case 'ge':
				case 'gte':
					$token = '>=';
				break;

				case '&&':
				case 'and':
					$token = '&&';
				break;

				case '||':
				case 'or':
					$token = '||';
				break;

				case '!':
				case 'not':
					$token = '!';
				break;

				case '%':
				case 'mod':
					$token = '%';
				break;

				case '(':
					array_push($is_arg_stack, $i);
				break;

				case 'is':
					$is_arg_start = ($tokens[$i-1] == ')') ? array_pop($is_arg_stack) : $i-1;
					$is_arg	= implode('	', array_slice($tokens,	$is_arg_start, $i -	$is_arg_start));

					$new_tokens	= $this->_parse_is_expr($is_arg, array_slice($tokens, $i+1));

					array_splice($tokens, $is_arg_start, sizeof($tokens), $new_tokens);

					$i = $is_arg_start;

				// no break

				default:
					if (preg_match('#^((?:[a-z0-9\-_]+\.)+)?(\$)?(?=[A-Z])([A-Z0-9\-_]+)#s', $token, $varrefs))
					{
						$token = (!empty($varrefs[1])) ? $this->generate_block_data_ref(substr($varrefs[1], 0, -1), true, $varrefs[2]) . '[\'' . $varrefs[3] . '\']' : (($varrefs[2]) ? '$this->_tpldata[\'DEFINE\'][\'.\'][\'' . $varrefs[3] . '\']' : '$this->_rootref[\'' . $varrefs[3] . '\']');
					}
					else if (preg_match('#^\.((?:[a-z0-9\-_]+\.?)+)$#s', $token, $varrefs))
					{
						// Allow checking if loops are set with .loopname
						// It is also possible to check the loop count by doing <!-- IF .loopname > 1 --> for example
						$blocks = explode('.', $varrefs[1]);

						// If the block is nested, we have a reference that we can grab.
						// If the block is not nested, we just go and grab the block from _tpldata
						if (sizeof($blocks) > 1)
						{
							$block = array_pop($blocks);
							$namespace = implode('.', $blocks);
							$varref = $this->generate_block_data_ref($namespace, true);

							// Add the block reference for the last child.
							$varref .= "['" . $block . "']";
						}
						else
						{
							$varref = '$this->_tpldata';

							// Add the block reference for the last child.
							$varref .= "['" . $blocks[0] . "']";
						}
						$token = "sizeof($varref)";
					}
					else if (!empty($token))
					{
						$token = '(' . $token . ')';
					}

				break;
			}
		}

		// If there are no valid tokens left or only control/compare characters left, we do skip this statement
		if (!sizeof($tokens) || str_replace(array(' ', '=', '!', '<', '>', '&', '|', '%', '(', ')'), '', implode('', $tokens)) == '')
		{
			$tokens = array('false');
		}
		return (($elseif) ? '} else if (' : 'if (') . (implode(' ', $tokens) . ') { ');
	}
	
	/**
	* Compile DEFINE tags
	* @access private
	*/
	private function compile_tag_define($tag_args, $op)
	{
		preg_match('#^((?:[a-z0-9\-_]+\.)+)?\$(?=[A-Z])([A-Z0-9_\-]*)(?: = (\'?)([^\']*)(\'?))?$#', $tag_args, $match);

		if (empty($match[2]) || (!isset($match[4]) && $op))
			return '';

		if (!$op)
			return 'unset(' . (($match[1]) ? $this->generate_block_data_ref(substr($match[1], 0, -1), true, true) . '[\'' . $match[2] . '\']' : '$this->_tpldata[\'DEFINE\'][\'.\'][\'' . $match[2] . '\']') . ');';
		
		// Are we a string?
		if ($match[3] && $match[5])
		{
			$match[4] = str_replace(array('\\\'', '\\\\', '\''), array('\'', '\\', '\\\''), $match[4]);

			// Compile reference, we allow template variables in defines...
			$match[4] = $this->compile($match[4]);

			// Now replace the php code
			$match[4] = "'" . str_replace(array('<?php echo ', '; ?>'), array("' . ", " . '"), $match[4]) . "'";
		}
		else
		{
			preg_match('#true|false|\.#i', $match[4], $type);

			switch (strtolower($type[0]))
			{
				case 'true':
				case 'false':
					$match[4] = strtoupper($match[4]);
				break;

				case '.':
					$match[4] = doubleval($match[4]);
				break;

				default:
					$match[4] = intval($match[4]);
				break;
			}
		}

		return (($match[1]) ? $this->generate_block_data_ref(substr($match[1], 0, -1), true, true) . '[\'' . $match[2] . '\']' : '$this->_tpldata[\'DEFINE\'][\'.\'][\'' . $match[2] . '\']') . ' = ' . $match[4] . ';';
	}
	
	/**
	* Compile INCLUDE tag
	* @access private
	*/
	private function compile_tag_include($tag_args)
	{
		return "\$this->_tpl_include('$tag_args');";
	}

	/**
	* Compile INCLUDE_PHP tag
	* @access private
	*/
	private function compile_tag_include_php($tag_args)
	{
		return "include('" . $tag_args . "');";
	}

	/**
	* parse expression
	* This is from Smarty
	* @access private
	*/
	private function _parse_is_expr($is_arg, $tokens)
	{
		$expr_end = 0;
		$negate_expr = false;

		if (($first_token = array_shift($tokens)) == 'not')
		{
			$negate_expr = true;
			$expr_type = array_shift($tokens);
		}
		else
		{
			$expr_type = $first_token;
		}

		switch ($expr_type)
		{
			case 'even':
				if (@$tokens[$expr_end] == 'by')
				{
					$expr_end++;
					$expr_arg = $tokens[$expr_end++];
					$expr = "!(($is_arg / $expr_arg) % $expr_arg)";
				}
				else
				{
					$expr = "!($is_arg & 1)";
				}
			break;

			case 'odd':
				if (@$tokens[$expr_end] == 'by')
				{
					$expr_end++;
					$expr_arg = $tokens[$expr_end++];
					$expr = "(($is_arg / $expr_arg) % $expr_arg)";
				}
				else
				{
					$expr = "($is_arg & 1)";
				}
			break;

			case 'div':
				if (@$tokens[$expr_end] == 'by')
				{
					$expr_end++;
					$expr_arg = $tokens[$expr_end++];
					$expr = "!($is_arg % $expr_arg)";
				}
			break;
		}

		if ($negate_expr)
		{
			$expr = "!($expr)";
		}

		array_splice($tokens, 0, $expr_end, $expr);

		return $tokens;
	}
	
	/**
	* Generates a reference to the given variable inside the given (possibly nested)
	* block namespace. This is a string of the form:
	* ' . $this->_tpldata['parent'][$_parent_i]['$child1'][$_child1_i]['$child2'][$_child2_i]...['varname'] . '
	* It's ready to be inserted into an "echo" line in one of the templates.
	* NOTE: expects a trailing "." on the namespace.
	* @access private
	*/
	private function generate_block_varref($namespace, $varname, $echo = true, $defop = false)
	{
		// Strip the trailing period.
		$namespace = substr($namespace, 0, -1);

		// Get a reference to the data block for this namespace.
		$varref = $this->generate_block_data_ref($namespace, true, $defop);
		// Prepend the necessary code to stick this in an echo line.

		// Append the variable reference.
		$varref .= "['$varname']";
		$varref = ($echo) ? "<?php echo $varref; ?>" : ((isset($varref)) ? $varref : '');

		return $varref;
	}

	/**
	* Generates a reference to the array of data values for the given
	* (possibly nested) block namespace. This is a string of the form:
	* $this->_tpldata['parent'][$_parent_i]['$child1'][$_child1_i]['$child2'][$_child2_i]...['$childN']
	*
	* If $include_last_iterator is true, then [$_childN_i] will be appended to the form shown above.
	* NOTE: does not expect a trailing "." on the blockname.
	* @access private
	*/
	private function generate_block_data_ref($blockname, $include_last_iterator, $defop = false)
	{
		// Get an array of the blocks involved.
		$blocks = explode('.', $blockname);
		$blockcount = sizeof($blocks) - 1;

		// DEFINE is not an element of any referenced variable, we must use _tpldata to access it
		if ($defop)
		{
			$varref = '$this->_tpldata[\'DEFINE\']';
			// Build up the string with everything but the last child.
			for ($i = 0; $i < $blockcount; $i++)
			{
				$varref .= "['" . $blocks[$i] . "'][\$_" . $blocks[$i] . '_i]';
			}
			// Add the block reference for the last child.
			$varref .= "['" . $blocks[$blockcount] . "']";
			// Add the iterator for the last child if requried.
			if ($include_last_iterator)
			{
				$varref .= '[$_' . $blocks[$blockcount] . '_i]';
			}
			return $varref;
		}
		else if ($include_last_iterator)
		{
			return '$_'. $blocks[$blockcount] . '_val';
		}
		else
		{
			return '$_'. $blocks[$blockcount - 1] . '_val[\''. $blocks[$blockcount]. '\']';
		}
	}

	/**
	* Write compiled file to cache directory
	* @access private
	*/
	private function compile_write($handle, $data)
	{
		$filename = $this->cachepath . str_replace('/', '.', $this->filename[$handle]) . '.' . self::PHPEX;

		if ($fp = @fopen($filename, 'wb'))
		{
			@flock($fp, LOCK_EX);
			@fwrite ($fp, $data);
			@flock($fp, LOCK_UN);
			@fclose($fp);

			/***phpbb_chmod($filename, CHMOD_WRITE);*/
		}

		return;
	}
}