<?

	$GLOBALS["INCLUDED_LIBS"]["PATTERNIZER"] = true;

	/**
	* Basic pattern parser
	*
	* Provides a low-level layer to parse patterns. It searches for commands like <%command%> inside the pattern and executes a specific function with him.
	* This command-interpreter is not implemented at this class level, the method command has to be overloaded by an extended, higher-level class, like patternizer_commandparser
	*
	* @author		Llorenç Herrera <hide@address.com>
	* @version		1.2
	* @package		patternizer
	*/
	class patternizer
	{
	
		/**
		* @access private
		*/
		var $tag_start				= "<%";
		/**
		* @access private
		*/
		var $tag_end				= "%>";
		
		/**
		* @access private
		*/
		var $tag_start_length;
		/**
		* @access private
		*/
		var $tag_end_length;
		
		/**
		* @access private
		*/
		function patternizer ()
		{
			$this->tag_start_length			= strlen ($this->tag_start);
			$this->tag_end_length			= strlen ($this->tag_end);
		}
		
		/**
		* Returns the parsed contents of a file (a pattern)
		*
		* @see patternizer::parse()
		* @param string $filename The file name of the pattern to parse
		* @return string The parsed contents of the pattern
		*/
		function patternize ($filename)
		{
			$pattern					= $this->getfile ($filename);
			if (!$pattern)
				return $this->error ("Could not access the requested pattern: <b>$filename</b>");
			$patternized				= $this->parse ($pattern);
			return $patternized;
		}
		
		/**
		* Parses the specified string and returns it
		*
		* Use this method if you want to parse a specific string, instead of a file.
		*
		* @see patternizer::patternize()
		* @param string $string String to parse
		* @return string The parsed string
		*/
		function parse ($string)
		{
			$pos = 0;
			$lastpos = 0;
			
			while (($pos = strpos ($string, $this->tag_start, $pos)) !== false)
			{
				$tag_start_pos = $pos;
				$tag_end_pos = strpos ($string, $this->tag_end, $pos + strlen ($this->tag_start));
				$pos = $tag_end_pos + $this->tag_end_length;
				$command = substr ($string, $tag_start_pos + $this->tag_start_length, $tag_end_pos - $tag_start_pos - $this->tag_end_length);
				$endstring .= substr ($string, $lastpos, $pos-$lastpos - strlen ($command) - $this->tag_start_length - $this->tag_end_length);
				$lastpos = $pos;
				$endstring .= $this->command ($command);
			}
			$endstring .= substr ($string, $lastpos);
			return $endstring;
		}
		
		/**
		* @access private
		*/
		function getfile ($filename)
		{
			if (!file_exists (realpath ($filename)) || !$fd = fopen (realpath ($filename), "r"))
				return false;
			$pattern = fread ($fd, filesize ($filename));
			fclose ($fd);
			return $pattern;
		}
		
		/**
		* Sets the start and end tags of the commands
		*
		* Defaults to <% and %>
		*
		* @param string $start Start tag, defaults to <%
		* @param string $end End tag, defaults to %>
		*/
		function settags ($start, $end)
		{
			$this->tag_start			= $start;
			$this->tag_end				= $end;
			$this->tag_start_length		= strlen ($start);
			$this->tag_end_length		= strlen ($end);
		}
		

		/**
		* @access private
		*/
		function error ($string)
		{
			return "<div style='font-family: Terminal, Courier, Courier New; font-size: 12px; color: #880000; background-color: #f4f4f4; border-width: 1px; border-style: dotted; padding: 3px;'><b>ERROR:</b> $string</div>";
		}
		
		// To be overloaded by patternizer higher-level classes
		/**
		* Internally called, this performs the specific stuff with the command that are found in the pattern
		*
		* It has to be overloaded by a higher-level extended class, like patternizer_commandparser {@link patternizer_commandparser}
		*
		* @param string $command The command that have been found in the pattern and has to be treated
		* @return string Whatever the overloaded method returns in relation to the stuff it does with the command
		*/
		function command ($command)
		{
			// This patternizer class can't execute commands, this method must be overloaded by higher level classes.
			return $this->error ("Command &lt;%$command%&gt; can't be executed at this patternizer class level.");
		}
		
	}

?>