/**

 		* Number of leading context "lines" to preserve.

 		*/

		var $_leading_context_lines = 5;

		/**

 		* Number of trailing context "lines" to preserve.

 		*/

		var $_trailing_context_lines = 3;

		/**

 		* Prefix for inserted text.

 		*/

		var $_ins_prefix = "<!-- Start added text -->\n<tr><td style='width: 0px;'>+</td><td class=\"diff-added\" style='width: 100%;'>";

		/**

 		* Suffix for inserted text.

 		*/

		var $_ins_suffix = "</td></tr>\n<!-- End added text -->\n\n";

		/**

 		* Prefix for deleted text.

 		*/

		var $_del_prefix = "<!-- Start deleted text -->\n<tr><td style='width: 0px;'>-</td><td class=\"diff-deleted\" style='width: 100%;'>";

		/**

 		* Suffix for deleted text.

 		*/

		var $_del_suffix = "</td></tr>\n<!-- End deleted text -->\n\n";

		/**

 		* 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 = 'lines';

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

		{

			return "<!-- Start block -->\n<tr><td colspan='2' class='diff-block'>Line $xbeg: {$this->_block_header}</td></tr>";

		}

		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("<br />", $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);

						}

						$ret = $prefix . $this->_deleted($orig) . $this->_added($final) . "\n";

						//echo 'DEBUG:<pre>'.htmlspecialchars($ret).'</pre>';

						return $ret;

				}

				$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. */

				$ret = str_replace($nl, "<br />", $renderer->render($diff));

				//echo 'DEBUG:<pre>'.htmlspecialchars($ret).'</pre>';

				return $ret . "\n";

		}

		function _splitOnWords($string, $newlineEscape = "<br />")

		{

				$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);

		}

		/**

 		* Renders a diff.

 		*

 		* @param Text_Diff $diff  A Text_Diff object.

 		*

 		* @return string  The formatted output.

 		*/

		function render($diff)

		{

				$xi = $yi = 1;

				$block = false;

				$context = array();

				$nlead = $this->_leading_context_lines;

				$ntrail = $this->_trailing_context_lines;

				$output = $this->_startDiff();

				$diffs = $diff->getDiff();

				foreach ($diffs as $i => $edit) {

						if (is_a($edit, 'Text_Diff_Op_copy')) {

								if (is_array($block)) {

										$keep = $i == count($diffs) - 1 ? $ntrail : $nlead + $ntrail;

										if (count($edit->orig) <= $keep) {

												$block[] = $edit;

										} else {

												if ($ntrail) {

														$context = array_slice($edit->orig, 0, $ntrail);

														$block[] = &new Text_Diff_Op_copy($context);

												}

												$bk = $this->_block($x0, $ntrail + $xi - $x0,

																						$y0, $ntrail + $yi - $y0,

																						$block);

												$output .= $bk;

												$block = false;

										}

								}

								$context = $edit->orig;

						} else {

								if (!is_array($block)) {

										$context = array_slice($context, count($context) - $nlead);

										$x0 = $xi - count($context);

										$y0 = $yi - count($context);

										$block = array();

										if ($context) {

												$block[] = &new Text_Diff_Op_copy($context);

										}

								}

								$block[] = $edit;

						}

						if ($edit->orig) {

								$xi += count($edit->orig);

						}

						if ($edit->final) {

								$yi += count($edit->final);

						}

				}

				if (is_array($block)) {

						$bk = $this->_block($x0, $xi - $x0,

																$y0, $yi - $y0,

																$block);

						$output .= $bk;

				}

				$final = $output . $this->_endDiff();

				if ($final == '') $final = '<tr><td class="diff-block">No differences.</td></tr>';

				//$final = preg_replace('#('.preg_quote($this->_ins_suffix).'|'.preg_quote($this->_del_suffix).')(.+?)('.preg_quote($this->_ins_prefix).'|'.preg_quote($this->_ins_suffix).')#', '\\1<tr><td></td><td class="diff-context>\\2</td></tr>\\3', $final);

				return '<table class="diff">'.$final.'</table>'."\n\n";

		}

		function _block($xbeg, $xlen, $ybeg, $ylen, &$edits)

		{

				$output = $this->_startBlock($this->_blockHeader($xbeg, $xlen, $ybeg, $ylen));

				foreach ($edits as $edit) {

						switch (strtolower(get_class($edit))) {

						case 'text_diff_op_copy':

								$output .= $this->_context($edit->orig);

								break;

						case 'text_diff_op_add':

								$output .= $this->_added($edit->final);

								break;

						case 'text_diff_op_delete':

								$output .= $this->_deleted($edit->orig);

								break;

						case 'text_diff_op_change':

								$output .= $this->_changed($edit->orig, $edit->final);

								break;

						}

				}

				return $output . $this->_endBlock();

		}