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

/**
* @package phpBB3
*
* Template class.
*
* Nathan Codding - Original version design and implementation
* Crimsonbane - Initial caching proposal and work
* psoTFX - Completion of file caching, decompilation routines and implementation of
* conditionals/keywords and associated changes
*
* The interface was inspired by PHPLib templates,  and the template file (formats are
* quite similar)
*
* The keyword/conditional implementation is currently based on sections of code from
* the Smarty templating engine (c) 2001 ispi of Lincoln, Inc. which is released
* (on its own and in whole) under the LGPL. Section 3 of the LGPL states that any code
* derived from an LGPL application may be relicenced under the GPL, this applies
* to this source
* 
* DEFINE directive inspired by a request by Cyberalien
*/
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
	var $_tpldata = array();

	// Root dir and hash of filenames for each template handle.
	var $tpl = '';
	var $root = '';
	var $cachepath = '';
	var $files = array();

	// this will hash handle names to the compiled/uncompiled code for that handle.
	var $compiled_code = array();

	// Various counters and storage arrays
	var $block_names = array();
	var $block_else_level = array();
	var $block_nesting_level = 0;

	var $static_lang;

	function set_template($static_lang = false)
	{
		global $phpbb_root_path, $config, $user;

		if (file_exists($phpbb_root_path . 'styles/' . $user->theme['primary']['template_path'] . '/template'))
		{
			$this->tpl = 'primary';
			$this->root = $phpbb_root_path . 'styles/' . $user->theme['primary']['template_path']. '/template';
			$this->cachepath = $phpbb_root_path . 'cache/tpl_' . $user->theme['primary']['template_path'] . '_';
		}
		else
		{
			$this->tpl = 'secondary';
			$this->root = $phpbb_root_path . 'styles/' . $user->theme['secondary']['template_path']. '/template';
			$this->cachepath = $phpbb_root_path . 'cache/tpl_' . $user->theme['secondary']['template_path'] . '_';
		}

		$this->static_lang = $static_lang;

		return true;
	}

	// Sets the template filenames for handles. $filename_array
	// should be a hash of handle => filename pairs.
	function set_filenames($filename_array)
	{
		if (!is_array($filename_array))
		{
			return false;
		}

		$template_names = '';
		foreach ($filename_array as $handle => $filename)
		{
			if (empty($filename))
			{
				trigger_error("template error - Empty filename specified for $handle", E_USER_ERROR);
			}

			$this->filename[$handle] = $filename;
			$this->files[$handle] = $this->root . '/' . $filename;
		}

		return true;
	}


	// Destroy template data set
	function destroy()
	{
		$this->_tpldata = array();
	}


	// Methods for loading and evaluating the templates
	function display($handle, $include_once = true)
	{
		global $user;

		if ($filename = $this->_tpl_load($handle))
		{
			($include_once) ? include_once($filename) : include($filename);
		}
		else
		{
			eval(' ?>' . $this->compiled_code[$handle] . '<?php ');
		}

		return true;
	}

	// Load a compiled template if possible, if not, recompile it
	function _tpl_load(&$handle)
	{
		global $config, $user, $db, $phpEx;

		$filename = $this->cachepath . $this->filename[$handle] . '.' . (($this->static_lang) ? $user->data['user_lang'] . '.' : '') . $phpEx;

		$recompile = (($config['load_tplcompile'] && @filemtime($filename) < filemtime($this->files[$handle])) || !file_exists($filename)) ? true : false;

		// Recompile page if the original template is newer, otherwise load the compiled version
		if (!$recompile)
		{
			return $filename;
		}


		// If the file for this handle is already loaded and compiled, do nothing.
		if (!empty($this->uncompiled_code[$handle]))
		{
			return true;
		}

		// 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);
		}

		if (!file_exists($this->files[$handle]) && !empty($user->theme['secondary']))
		{
			$this->tpl = 'secondary';
			$this->files[$handle] = $phpbb_root_path . 'styles/' . $user->theme['secondary']['template_path'] . '/template/' . $this->filename[$handle];
		}

		if ($user->theme[$this->tpl]['template_storedb'])
		{
			$sql = 'SELECT * FROM ' . STYLES_TPLDATA_TABLE . '
				WHERE template_id = ' . $user->theme[$this->tpl]['template_id'] . "
					AND (template_filename = '" . $db->sql_escape($this->filename[$handle]) . "'
						OR template_included LIKE '%" . $db->sql_escape($this->filename[$handle]) . ":%')";
			$result = $db->sql_query($sql);

			if ($row = $db->sql_fetchrow($result))
			{
				do
				{
					if ($row['template_mtime'] < filemtime($phpbb_root_path . 'styles/' . $user->theme[$this->tpl]['template_path'] . '/template/' . $row['template_filename']))
					{
						if ($row['template_filename'] == $this->filename[$handle])
						{
							$this->_tpl_load_file($handle);
						}
						else
						{
							$this->files[$row['template_filename']] = $this->root . '/' . $row['template_filename'];
							$this->_tpl_load_file($row['template_filename']);
							unset($this->compiled_code[$row['template_filename']]);
							unset($this->files[$row['template_filename']]);
						}
					}

					if ($row['template_filename'] == $this->filename[$handle])
					{
						$this->compiled_code[$handle] = $this->compile(trim($row['template_data']));
						$this->compile_write($handle, $this->compiled_code[$handle]);
					}
					else
					{
						// Only bother compiling if it doesn't already exist
						if (!file_exists($this->cachepath . $row['template_filename'] . '.' . (($this->static_lang) ? $user->data['user_lang'] . '.' : '') . $phpEx))
						{
							$this->filename[$row['template_filename']] = $row['template_filename'];
							$this->compile_write($row['template_filename'], $this->compile(trim($row['template_data'])));
							unset($this->filename[$row['template_filename']]);
						}
					}
				}
				while ($row = $db->sql_fetchrow($result));
			}
			$db->sql_freeresult($result);
			return false;
		}

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

	// Load template source from file
	function _tpl_load_file($handle)
	{
		// Try and open template for read
		if (!($fp = @fopen($this->files[$handle], 'r')))
		{
			trigger_error("template->_tpl_load_file(): File {$this->files[$handle]} does not exist or is empty", E_USER_ERROR);
		}

		$this->compiled_code[$handle] = $this->compile(trim(@fread($fp, filesize($this->files[$handle]))));
		@fclose($fp);

		// Actually compile the code now.
		$this->compile_write($handle, $this->compiled_code[$handle]);
	}

	// Assign key variable pairs from an array
	function assign_vars($vararray)
	{
		foreach ($vararray as $key => $val)
		{
			$this->_tpldata['.'][0][$key] = $val;
		}

		return true;
	}

	// Assign a single variable to a single key
	function assign_var($varname, $varval)
	{
		$this->_tpldata['.'][0][$varname] = $varval;

		return true;
	}

	// Assign key variable pairs from an array to a specified block
	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]];
				$str = &$str[sizeof($str) - 1];
			}

			$vararray['S_ROW_COUNT'] = sizeof($str[$blocks[$blockcount]]);
			
			// Assign S_FIRST_ROW
			if (sizeof($str[$blocks[$blockcount]]) == 0)
			{
				$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)
			$vararray['S_LAST_ROW'] = true;
			if (sizeof($str[$blocks[$blockcount]]) > 0)
			{
				unset($str[$blocks[$blockcount]][sizeof($str[$blocks[$blockcount]]) - 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.
			$vararray['S_ROW_COUNT'] = sizeof($this->_tpldata[$blockname]);

			// Assign S_FIRST_ROW
			if (sizeof($this->_tpldata[$blockname]) == 0)
			{
				$vararray['S_FIRST_ROW'] = true;
			}

			// We always assign S_LAST_ROW and remove the entry before
			$vararray['S_LAST_ROW'] = true;
			if (sizeof($this->_tpldata[$blockname]) > 0)
			{
				unset($this->_tpldata[$blockname][sizeof($this->_tpldata[$blockname]) - 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)
	*
	* Some Examples:
	* <code>
	*
	* alter_block_array('loop', $varrarray); // Insert vararray at the end
	* alter_block_array('loop', $vararray, 2); // Insert vararray at position 2
	* alter_block_array('loop', $vararray, array('KEY' => 'value')); // Insert vararray at the position where the key 'KEY' has the value of 'value' 
	* alter_block_array('loop', $vararray, false); // Insert vararray at first position
	* alter_block_array('loop', $vararray, true); //Insert vararray at last position (assign_block_vars equivalence)
	*
	* alter_block_array('loop', $vararray, 2, 'change'); // Change/Merge vararray with existing array at position 2
	* alter_block_array('loop', $vararray, array('KEY' => 'value'), 'change'); // Change/Merge vararray with existing array at the position where the key 'KEY' has the value of 'value' 
	* alter_block_array('loop', $vararray, false, 'change'); // Change/Merge vararray with existing array at first position
	* alter_block_array('loop', $vararray, true, 'change'); // Change/Merge vararray with existing array at last position
	*
	* </code>
	*
	* @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 insert|change $mode Mode to execute
	*
	*	If insert, the vararray is inserted at the given position (position counting from zero). 
	*
	*	If change, the current block gets merged with the vararray (resulting in new key/value pairs be added and existing keys be replaced by the new value).
	*
	* Since counting begins by zero, inserting at the last position will result in this array: array(vararray, last positioned array)
	* and inserting at position 1 will result in this array: array(first positioned array, vararray, following vars)
	*
	*/
	function alter_block_array($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])-1;
		}

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

	// Include a seperate template
	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)
		{
			global $user;

			if ($filename)
			{
				include_once($filename);
				return;
			}
			eval(' ?>' . $this->compiled_code[$handle] . '<?php ');
		}
	}


	// This next set of methods could be seperated off and included since
	// they deal exclusively with compilation ... which is done infrequently
	// and would save a fair few kb


	// The all seeing all doing compile method. Parts are inspired by or directly
	// from Smarty
	function compile($code, $no_echo = false, $echo_var = '')
	{
		global $config;

		// 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 >
		$match_php_tags = array('#\<\?php .*?\?\>#is', '#\<\script language="php"\>.*?\<\/script\>#is', '#\<\?.*?\?\>#s', '#\<%.*?%\>#s');
		$code = preg_replace($match_php_tags, '', $code);

		// Pull out all block/statement level elements and seperate 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);
		$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, $tb_size = sizeof($text_blocks); $curr_tb < $tb_size; $curr_tb++)
		{
			switch ($blocks[1][$curr_tb])
			{
				case 'BEGIN':
					$this->block_else_level[] = false;
					$compile_blocks[] = '<?php ' . $this->compile_tag_block($blocks[2][$curr_tb]) . ' ?>';
					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 ' . $this->compile_tag_if($blocks[2][$curr_tb], false) . ' ?>';
					break;

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

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

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

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

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

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

				case 'INCLUDEPHP':
					if ($config['tpl_php'])
					{
						$temp = '';
						list(, $temp) = each($includephp_blocks);
						$compile_blocks[] = '<?php ' . $this->compile_tag_include_php($temp) . ' ?>';
					}
					else
					{
						$compile_blocks[] = '';
					}
					break;

				case 'PHP':
					if ($config['tpl_php'])
					{
						$temp = '';
						list(, $temp) = each($php_blocks);
						$compile_blocks[] = '<?php ' . $temp . ' ?>';
					}
					else
					{
						$compile_blocks[] = '';
					}
					break;

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

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

		// There will be a number of occassions 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 . "'";
	}

	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);

		for ($j = 0, $size = sizeof($varrefs[1]); $j < $size; $j++)
		{
			$namespace = $varrefs[1][$j];
			$varname = $varrefs[4][$j];
			$new = $this->generate_block_varref($namespace, $varname, true, $varrefs[3][$j]);

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

		// This will handle the remaining root-level varrefs
		if (!$this->static_lang)
		{
			$text_blocks = preg_replace('#\{L_([a-z0-9\-_]*?)\}#is', "<?php echo ((isset(\$this->_tpldata['.'][0]['L_\\1'])) ? \$this->_tpldata['.'][0]['L_\\1'] : ((isset(\$user->lang['\\1'])) ? \$user->lang['\\1'] : '{ ' . ucfirst(strtolower(str_replace('_', ' ', '\\1'))) . ' 	}')); ?>", $text_blocks);
		}
		else
		{
			global $user;

			$text_blocks = preg_replace('#\{L_([A-Z0-9\-_]*?)\}#e', "'<?php echo ((isset(\$this->_tpldata[\'.\'][0][\'L_\\1\'])) ? \$this->_tpldata[\'.\'][0][\'L_\\1\'] : \'' . ((isset(\$user->lang['\\1'])) ? \$user->lang['\\1'] : '') . '\'); ?>'" , $text_blocks);
		}

		$text_blocks = preg_replace('#\{([a-z0-9\-_]*?)\}#is', "<?php echo \$this->_tpldata['.'][0]['\\1']; ?>", $text_blocks);
		$text_blocks = preg_replace('#\{\$([a-z0-9\-_]*?)\}#is', "<?php echo \$this->_tpldata['DEFINE']['.']['\\1']; ?>", $text_blocks);

		return;
	}

	function compile_tag_block($tag_args)
	{
		// 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('#^(.*?)\(([\-0-9]+)(,([\-0-9]+))?\)$#', $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[4]) < 1 || $match[4] == -1)
			{
				$loop_end = '$_' . $tag_args . '_count';
			}
			else if ($match[4] >= 0)
			{
				$loop_end = '(' . ($match[4] + 1) . ' > $_' . $tag_args . '_count ? $_' . $tag_args . '_count : ' . ($match[4] + 1) . ')';
			}
			else //if ($match[4] < -1)
			{
				$loop_end = '$_' . $tag_args . '_count' . ($match[4] + 1);
			}
		}
		else
		{
			$loop_start = 0;
			$loop_end = '$_' . $tag_args . '_count';
		}

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

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

			// Generate a namespace string for this block.
			$namespace = implode('.', $this->block_names);

			// 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) {';
		$tag_template_php .= 'for ($this->_' . $tag_args . '_i = ' . $loop_start . '; $this->_' . $tag_args . '_i < ' . $loop_end . '; $this->_' . $tag_args . '_i++){';

		return $tag_template_php;
	}

	//
	// Compile IF tags - much of this is from Smarty with
	// some adaptions for our block level methods
	//
	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 '||':
				case '|':
				case '^':
				case '&':
				case '~':
				case ')':
				case ',':
				case '+':
				case '-':
				case '*':
				case '/':
				case '@':
					break;

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

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

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

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

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

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

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

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

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

				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;

				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[3]) . '[\'' . $varrefs[4] . '\']' : (($varrefs[3]) ? '$this->_tpldata[\'DEFINE\'][\'.\'][\'' . $varrefs[4] . '\']' : '$this->_tpldata[\'.\'][0][\'' . $varrefs[4] . '\']');
					}
					break;
			}
		}

		return (($elseif) ? '} elseif (' : 'if (') . (implode(' ', $tokens) . ') { ');
	}

	function compile_tag_define($tag_args, $op)
	{
		preg_match('#^(([a-z0-9\-_]+?\.)+?)?\$([A-Z][A-Z0-9_\-]*?)( = (\'?)(.*?)(\'?))?$#', $tag_args, $match);

		if (empty($match[3]) || (empty($match[6]) && $op))
		{
			return;
		}

		if (!$op)
		{
			return 'unset(' . (($match[1]) ? $this->generate_block_data_ref(substr($match[1], 0, -1), true, true) . '[\'' . $match[3] . '\']' : '$this->_tpldata[\'DEFINE\'][\'.\'][\'' . $match[3] . '\']') . ');';
		}

		// Are we a string?
		if ($match[5] && $match[7])
		{
			$match[6] = "'" . addslashes(str_replace(array('\\\'', '\\\\'), array('\'', '\\'), $match[6])) . "'";
		}
		else
		{
			preg_match('#(true|false|\.)#i', $match[6], $type);

			switch (strtolower($type[1]))
			{
				case 'true':
				case 'false':
					$match[6] = strtoupper($match[6]);
					break;
				case '.';
					$match[6] = doubleval($match[6]);
					break;
				default:
					$match[6] = intval($match[6]);
					break;
			}
		}

		return (($match[1]) ? $this->generate_block_data_ref(substr($match[1], 0, -1), true, true) . '[\'' . $match[3] . '\']' : '$this->_tpldata[\'DEFINE\'][\'.\'][\'' . $match[3] . '\']') . ' = ' . $match[6] . ';';
	}

	function compile_tag_include($tag_args)
	{
		return "\$this->_tpl_include('$tag_args');";
	}

	function compile_tag_include_php($tag_args)
	{
		return "include('" . $this->root . '/' . $tag_args . "');";
	}

	// This is from Smarty
	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 % 2)";
				}
				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 %	2)";
				}
				break;

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

			default:
				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.
	*/
	function generate_block_varref($namespace, $varname, $echo = true, $defop = false)
	{
		// Strip the trailing period.
		$namespace = substr($namespace, 0, strlen($namespace) - 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.
	*/
	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;
		$varref = '$this->_tpldata' . (($defop) ? '[\'DEFINE\']' : '');

		// Build up the string with everything but the last child.
		for ($i = 0; $i < $blockcount; $i++)
		{
			$varref .= "['" . $blocks[$i] . "'][\$this->_" . $blocks[$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)
		{
			$varref .= '[$this->_' . $blocks[$blockcount] . '_i]';
		}

		return $varref;
	}

	function compile_write(&$handle, $data)
	{
		global $phpEx, $user;

		$filename = $this->cachepath . $this->filename[$handle] . '.' . (($this->static_lang) ? $user->data['user_lang'] . '.' : '') . $phpEx;

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

			@umask(0);
			@chmod($filename, 0644);
		}

		return;
	}
}

?>