/**

 		* Number of leading context "lines" to preserve.

 		*/

		var $_leading_context_lines = 10000;

		/**

 		* Number of trailing context "lines" to preserve.

 		*/

		var $_trailing_context_lines = 10000;

		/**

 		* Prefix for inserted text.

 		*/

		var $_ins_prefix = '<ins>';

		/**

 		* Suffix for inserted text.

 		*/

		var $_ins_suffix = '</ins>';

		/**

 		* Prefix for deleted text.

 		*/

		var $_del_prefix = '<del>';

		/**

 		* Suffix for deleted text.

 		*/

		var $_del_suffix = '</del>';

		/**

 		* Header for each change block.

 		*/

		var $_block_header = '';

		/**

 		* What are we currently splitting on? Used to recurse to show word-level

 		* changes.

 		*/

		var $_split_level = 'words';

		function _blockHeader($xbeg, $xlen, $ybeg, $ylen)

		{

				return $this->_block_header;

		}

		function _startBlock($header)

		{

				return $header;

		}

		function _lines($lines, $prefix = ' ', $encode = true)

		{

				if ($encode) {

						array_walk($lines, array(&$this, '_encode'));

				}

				if ($this->_split_level == 'words') {

						return implode('', $lines);

				} else {

						return implode("\n", $lines) . "\n";

				}

		}

		function _added($lines)

		{

				array_walk($lines, array(&$this, '_encode'));

				$lines[0] = $this->_ins_prefix . $lines[0];

				$lines[count($lines) - 1] .= $this->_ins_suffix;

				return $this->_lines($lines, ' ', false);

		}

		function _deleted($lines, $words = false)

		{

				array_walk($lines, array(&$this, '_encode'));

				$lines[0] = $this->_del_prefix . $lines[0];

				$lines[count($lines) - 1] .= $this->_del_suffix;

				return $this->_lines($lines, ' ', false);

		}

		function _context($lines)

		{

				return "<!-- Start context -->\n<tr><td></td><td class=\"diff-context\">".$this->_lines($lines).'</td></tr>'."\n<!-- End context -->\n\n";

		}

		function _changed($orig, $final)

		{

				/* If we've already split on words, don't try to do so again - just

 				* display. */

				if ($this->_split_level == 'words') {

						$prefix = '';

						while ($orig[0] !== false && $final[0] !== false &&

 									substr($orig[0], 0, 1) == ' ' &&

 									substr($final[0], 0, 1) == ' ') {

								$prefix .= substr($orig[0], 0, 1);

								$orig[0] = substr($orig[0], 1);

								$final[0] = substr($final[0], 1);

						}

						return $prefix . $this->_deleted($orig) . $this->_added($final);

				}

				$text1 = implode("\n", $orig);

				$text2 = implode("\n", $final);

				/* Non-printing newline marker. */

				$nl = "\0";

				/* We want to split on word boundaries, but we need to

 				* preserve whitespace as well. Therefore we split on words,

 				* but include all blocks of whitespace in the wordlist. */

				$diff = &new Text_Diff($this->_splitOnWords($text1, $nl),

 															$this->_splitOnWords($text2, $nl));

				/* Get the diff in inline format. */

				$renderer = &new Text_Diff_Renderer_inline(array_merge($this->getParams(),

 																															array('split_level' => 'words')));

				/* Run the diff and get the output. */

				return str_replace($nl, "\n", $renderer->render($diff)) . "\n";

		}

		function _splitOnWords($string, $newlineEscape = "\n")

		{

				$words = array();

				$length = strlen($string);

				$pos = 0;

				while ($pos < $length) {

						// Eat a word with any preceding whitespace.

						$spaces = strspn(substr($string, $pos), " \n");

						$nextpos = strcspn(substr($string, $pos + $spaces), " \n");

						$words[] = str_replace("\n", $newlineEscape, substr($string, $pos, $spaces + $nextpos));

						$pos += $spaces + $nextpos;

				}

				return $words;

		}

		function _encode(&$string)

		{

				$string = htmlspecialchars($string);

		}