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    Current File : /home/m/e/h/meharicl/www/phpBB3/includes/diff/diff.php

    <?php
    /**
    *
    * This file is part of the phpBB Forum Software package.
    *
    * @copyright (c) phpBB Limited <https://www.phpbb.com>
    * @license GNU General Public License, version 2 (GPL-2.0)
    *
    * For full copyright and license information, please see
    * the docs/CREDITS.txt file.
    *
    */
    
    /**
    * @ignore
    */
    if (!defined('IN_PHPBB'))
    {
    	exit;
    }
    
    /**
    * Code from pear.php.net, Text_Diff-1.1.0 package
    * http://pear.php.net/package/Text_Diff/
    *
    * Modified by phpBB Limited to meet our coding standards
    * and being able to integrate into phpBB
    *
    * General API for generating and formatting diffs - the differences between
    * two sequences of strings.
    *
    * Copyright 2004 Geoffrey T. Dairiki <dairiki@dairiki.org>
    * Copyright 2004-2008 The Horde Project (http://www.horde.org/)
    *
    * @package diff
    * @author  Geoffrey T. Dairiki <dairiki@dairiki.org>
    */
    class diff
    {
    	/**
    	* Array of changes.
    	* @var array
    	*/
    	var $_edits;
    
    	/**
    	* Computes diffs between sequences of strings.
    	*
    	* @param array	&$from_content	An array of strings. Typically these are lines from a file.
    	* @param array	&$to_content	An array of strings.
    	* @param bool	$preserve_cr	If true, \r is replaced by a new line in the diff output
    	*/
    	function __construct(&$from_content, &$to_content, $preserve_cr = true)
    	{
    		$diff_engine = new diff_engine();
    		$this->_edits = $diff_engine->diff($from_content, $to_content, $preserve_cr);
    	}
    
    	/**
    	* Returns the array of differences.
    	*/
    	function get_diff()
    	{
    		return $this->_edits;
    	}
    
    	/**
    	* returns the number of new (added) lines in a given diff.
    	*
    	* @since Text_Diff 1.1.0
    	*
    	* @return integer The number of new lines
    	*/
    	function count_added_lines()
    	{
    		$count = 0;
    
    		for ($i = 0, $size = count($this->_edits); $i < $size; $i++)
    		{
    			$edit = $this->_edits[$i];
    
    			if (is_a($edit, 'diff_op_add') || is_a($edit, 'diff_op_change'))
    			{
    				$count += $edit->nfinal();
    			}
    		}
    		return $count;
    	}
    
    	/**
    	* Returns the number of deleted (removed) lines in a given diff.
    	*
    	* @since Text_Diff 1.1.0
    	*
    	* @return integer The number of deleted lines
    	*/
    	function count_deleted_lines()
    	{
    		$count = 0;
    
    		for ($i = 0, $size = count($this->_edits); $i < $size; $i++)
    		{
    			$edit = $this->_edits[$i];
    
    			if (is_a($edit, 'diff_op_delete') || is_a($edit, 'diff_op_change'))
    			{
    				$count += $edit->norig();
    			}
    		}
    		return $count;
    	}
    
    	/**
    	* Computes a reversed diff.
    	*
    	* Example:
    	* <code>
    	* $diff = new diff($lines1, $lines2);
    	* $rev = $diff->reverse();
    	* </code>
    	*
    	* @return diff  A Diff object representing the inverse of the original diff.
    	*               Note that we purposely don't return a reference here, since
    	*               this essentially is a clone() method.
    	*/
    	function reverse()
    	{
    		if (version_compare(zend_version(), '2', '>'))
    		{
    			$rev = clone($this);
    		}
    		else
    		{
    			$rev = $this;
    		}
    
    		$rev->_edits = array();
    
    		for ($i = 0, $size = count($this->_edits); $i < $size; $i++)
    		{
    			$edit = $this->_edits[$i];
    			$rev->_edits[] = $edit->reverse();
    		}
    
    		return $rev;
    	}
    
    	/**
    	* Checks for an empty diff.
    	*
    	* @return boolean  True if two sequences were identical.
    	*/
    	function is_empty()
    	{
    		for ($i = 0, $size = count($this->_edits); $i < $size; $i++)
    		{
    			$edit = $this->_edits[$i];
    
    			// skip diff_op_copy
    			if (is_a($edit, 'diff_op_copy'))
    			{
    				continue;
    			}
    
    			if (is_a($edit, 'diff_op_delete') || is_a($edit, 'diff_op_add'))
    			{
    				$orig = $edit->orig;
    				$final = $edit->final;
    
    				// We can simplify one case where the array is usually supposed to be empty...
    				if (count($orig) == 1 && trim($orig[0]) === '') $orig = array();
    				if (count($final) == 1 && trim($final[0]) === '') $final = array();
    
    				if (!$orig && !$final)
    				{
    					continue;
    				}
    
    				return false;
    			}
    
    			return false;
    		}
    
    		return true;
    	}
    
    	/**
    	* Computes the length of the Longest Common Subsequence (LCS).
    	*
    	* This is mostly for diagnostic purposes.
    	*
    	* @return integer  The length of the LCS.
    	*/
    	function lcs()
    	{
    		$lcs = 0;
    
    		for ($i = 0, $size = count($this->_edits); $i < $size; $i++)
    		{
    			$edit = $this->_edits[$i];
    
    			if (is_a($edit, 'diff_op_copy'))
    			{
    				$lcs += count($edit->orig);
    			}
    		}
    		return $lcs;
    	}
    
    	/**
    	* Gets the original set of lines.
    	*
    	* This reconstructs the $from_lines parameter passed to the constructor.
    	*
    	* @return array  The original sequence of strings.
    	*/
    	function get_original()
    	{
    		$lines = array();
    
    		for ($i = 0, $size = count($this->_edits); $i < $size; $i++)
    		{
    			$edit = $this->_edits[$i];
    
    			if ($edit->orig)
    			{
    				array_splice($lines, count($lines), 0, $edit->orig);
    			}
    		}
    		return $lines;
    	}
    
    	/**
    	* Gets the final set of lines.
    	*
    	* This reconstructs the $to_lines parameter passed to the constructor.
    	*
    	* @return array  The sequence of strings.
    	*/
    	function get_final()
    	{
    		$lines = array();
    
    		for ($i = 0, $size = count($this->_edits); $i < $size; $i++)
    		{
    			$edit = $this->_edits[$i];
    
    			if ($edit->final)
    			{
    				array_splice($lines, count($lines), 0, $edit->final);
    			}
    		}
    		return $lines;
    	}
    
    	/**
    	* Removes trailing newlines from a line of text. This is meant to be used with array_walk().
    	*
    	* @param string &$line  The line to trim.
    	* @param integer $key  The index of the line in the array. Not used.
    	*/
    	function trim_newlines(&$line, $key)
    	{
    		$line = str_replace(array("\n", "\r"), '', $line);
    	}
    
    	/**
    	* Checks a diff for validity.
    	*
    	* This is here only for debugging purposes.
    	*/
    	function _check($from_lines, $to_lines)
    	{
    		if (serialize($from_lines) != serialize($this->get_original()))
    		{
    			trigger_error("[diff] Reconstructed original doesn't match", E_USER_ERROR);
    		}
    
    		if (serialize($to_lines) != serialize($this->get_final()))
    		{
    			trigger_error("[diff] Reconstructed final doesn't match", E_USER_ERROR);
    		}
    
    		$rev = $this->reverse();
    
    		if (serialize($to_lines) != serialize($rev->get_original()))
    		{
    			trigger_error("[diff] Reversed original doesn't match", E_USER_ERROR);
    		}
    
    		if (serialize($from_lines) != serialize($rev->get_final()))
    		{
    			trigger_error("[diff] Reversed final doesn't match", E_USER_ERROR);
    		}
    
    		$prevtype = null;
    
    		for ($i = 0, $size = count($this->_edits); $i < $size; $i++)
    		{
    			$edit = $this->_edits[$i];
    
    			if ($prevtype == get_class($edit))
    			{
    				trigger_error("[diff] Edit sequence is non-optimal", E_USER_ERROR);
    			}
    			$prevtype = get_class($edit);
    		}
    
    		return true;
    	}
    }
    
    /**
    * @package diff
    * @author  Geoffrey T. Dairiki <dairiki@dairiki.org>
    */
    class mapped_diff extends diff
    {
    	/**
    	* Computes a diff between sequences of strings.
    	*
    	* This can be used to compute things like case-insensitve diffs, or diffs
    	* which ignore changes in white-space.
    	*
    	* @param array $from_lines         An array of strings.
    	* @param array $to_lines           An array of strings.
    	* @param array $mapped_from_lines  This array should have the same size number of elements as $from_lines.
    	*                                  The elements in $mapped_from_lines and $mapped_to_lines are what is actually
    	*                                  compared when computing the diff.
    	* @param array $mapped_to_lines    This array should have the same number of elements as $to_lines.
    	*/
    	function __construct(&$from_lines, &$to_lines, &$mapped_from_lines, &$mapped_to_lines)
    	{
    		if (count($from_lines) != count($mapped_from_lines) || count($to_lines) != count($mapped_to_lines))
    		{
    			return false;
    		}
    
    		parent::__construct($mapped_from_lines, $mapped_to_lines);
    
    		$xi = $yi = 0;
    		for ($i = 0; $i < count($this->_edits); $i++)
    		{
    			$orig = &$this->_edits[$i]->orig;
    			if (is_array($orig))
    			{
    				$orig = array_slice($from_lines, $xi, count($orig));
    				$xi += count($orig);
    			}
    
    			$final = &$this->_edits[$i]->final;
    			if (is_array($final))
    			{
    				$final = array_slice($to_lines, $yi, count($final));
    				$yi += count($final);
    			}
    		}
    	}
    }
    
    /**
    * @package diff
    * @author  Geoffrey T. Dairiki <dairiki@dairiki.org>
    *
    * @access private
    */
    class diff_op
    {
    	var $orig;
    	var $final;
    
    	function &reverse()
    	{
    		trigger_error('[diff] Abstract method', E_USER_ERROR);
    	}
    
    	function norig()
    	{
    		return ($this->orig) ? count($this->orig) : 0;
    	}
    
    	function nfinal()
    	{
    		return ($this->final) ? count($this->final) : 0;
    	}
    }
    
    /**
    * @package diff
    * @author  Geoffrey T. Dairiki <dairiki@dairiki.org>
    *
    * @access private
    */
    class diff_op_copy extends diff_op
    {
    	function __construct($orig, $final = false)
    	{
    		if (!is_array($final))
    		{
    			$final = $orig;
    		}
    		$this->orig = $orig;
    		$this->final = $final;
    	}
    
    	function &reverse()
    	{
    		$reverse = new diff_op_copy($this->final, $this->orig);
    		return $reverse;
    	}
    }
    
    /**
    * @package diff
    * @author  Geoffrey T. Dairiki <dairiki@dairiki.org>
    *
    * @access private
    */
    class diff_op_delete extends diff_op
    {
    	function __construct($lines)
    	{
    		$this->orig = $lines;
    		$this->final = false;
    	}
    
    	function &reverse()
    	{
    		$reverse = new diff_op_add($this->orig);
    		return $reverse;
    	}
    }
    
    /**
    * @package diff
    * @author  Geoffrey T. Dairiki <dairiki@dairiki.org>
    *
    * @access private
    */
    class diff_op_add extends diff_op
    {
    	function __construct($lines)
    	{
    		$this->final = $lines;
    		$this->orig = false;
    	}
    
    	function &reverse()
    	{
    		$reverse = new diff_op_delete($this->final);
    		return $reverse;
    	}
    }
    
    /**
    * @package diff
    * @author  Geoffrey T. Dairiki <dairiki@dairiki.org>
    *
    * @access private
    */
    class diff_op_change extends diff_op
    {
    	function __construct($orig, $final)
    	{
    		$this->orig = $orig;
    		$this->final = $final;
    	}
    
    	function &reverse()
    	{
    		$reverse = new diff_op_change($this->final, $this->orig);
    		return $reverse;
    	}
    }
    
    
    /**
    * A class for computing three way diffs.
    *
    * @package diff
    * @author  Geoffrey T. Dairiki <dairiki@dairiki.org>
    */
    class diff3 extends diff
    {
    	/**
    	* Conflict counter.
    	* @var integer
    	*/
    	var $_conflicting_blocks = 0;
    
    	/**
    	* Computes diff between 3 sequences of strings.
    	*
    	* @param array &$orig		The original lines to use.
    	* @param array &$final1		The first version to compare to.
    	* @param array &$final2		The second version to compare to.
    	* @param bool $preserve_cr	If true, \r\n and bare \r are replaced by a new line
    	*							in the diff output
    	*/
    	function __construct(&$orig, &$final1, &$final2, $preserve_cr = true)
    	{
    		$diff_engine = new diff_engine();
    
    		$diff_1 = $diff_engine->diff($orig, $final1, $preserve_cr);
    		$diff_2 = $diff_engine->diff($orig, $final2, $preserve_cr);
    
    		unset($diff_engine);
    
    		$this->_edits = $this->_diff3($diff_1, $diff_2);
    	}
    
    	/**
    	* Return number of conflicts
    	*/
    	function get_num_conflicts()
    	{
    		$conflicts = 0;
    
    		for ($i = 0, $size = count($this->_edits); $i < $size; $i++)
    		{
    			$edit = $this->_edits[$i];
    
    			if ($edit->is_conflict())
    			{
    				$conflicts++;
    			}
    		}
    
    		return $conflicts;
    	}
    
    	/**
    	* Get conflicts content for download. This is generally a merged file, but preserving conflicts and adding explanations to it.
    	* A user could then go through this file, search for the conflicts and changes the code accordingly.
    	*
    	* @param string $label1 the cvs file version/label from the original set of lines
    	* @param string $label2 the cvs file version/label from the new set of lines
    	* @param string $label_sep the explanation between label1 and label2 - more of a helper for the user
    	*
    	* @return mixed the merged output
    	*/
    	function get_conflicts_content($label1 = 'CURRENT_FILE', $label2 = 'NEW_FILE', $label_sep = 'DIFF_SEP_EXPLAIN')
    	{
    		global $user;
    
    		$label1 = (!empty($user->lang[$label1])) ? $user->lang[$label1] : $label1;
    		$label2 = (!empty($user->lang[$label2])) ? $user->lang[$label2] : $label2;
    		$label_sep = (!empty($user->lang[$label_sep])) ? $user->lang[$label_sep] : $label_sep;
    
    		$lines = array();
    
    		for ($i = 0, $size = count($this->_edits); $i < $size; $i++)
    		{
    			$edit = $this->_edits[$i];
    
    			if ($edit->is_conflict())
    			{
    				// Start conflict label
    				$label_start	= array('<<<<<<< ' . $label1);
    				$label_mid		= array('======= ' . $label_sep);
    				$label_end		= array('>>>>>>> ' . $label2);
    
    				$lines = array_merge($lines, $label_start, $edit->final1, $label_mid, $edit->final2, $label_end);
    				$this->_conflicting_blocks++;
    			}
    			else
    			{
    				$lines = array_merge($lines, $edit->merged());
    			}
    		}
    
    		return $lines;
    	}
    
    	/**
    	* Return merged output (used by the renderer)
    	*
    	* @return mixed the merged output
    	*/
    	function merged_output()
    	{
    		return $this->get_conflicts_content();
    	}
    
    	/**
    	* Merge the output and use the new file code for conflicts
    	*/
    	function merged_new_output()
    	{
    		$lines = array();
    
    		for ($i = 0, $size = count($this->_edits); $i < $size; $i++)
    		{
    			$edit = $this->_edits[$i];
    
    			if ($edit->is_conflict())
    			{
    				$lines = array_merge($lines, $edit->final2);
    			}
    			else
    			{
    				$lines = array_merge($lines, $edit->merged());
    			}
    		}
    
    		return $lines;
    	}
    
    	/**
    	* Merge the output and use the original file code for conflicts
    	*/
    	function merged_orig_output()
    	{
    		$lines = array();
    
    		for ($i = 0, $size = count($this->_edits); $i < $size; $i++)
    		{
    			$edit = $this->_edits[$i];
    
    			if ($edit->is_conflict())
    			{
    				$lines = array_merge($lines, $edit->final1);
    			}
    			else
    			{
    				$lines = array_merge($lines, $edit->merged());
    			}
    		}
    
    		return $lines;
    	}
    
    	/**
    	* Get conflicting block(s)
    	*/
    	function get_conflicts()
    	{
    		$conflicts = array();
    
    		for ($i = 0, $size = count($this->_edits); $i < $size; $i++)
    		{
    			$edit = $this->_edits[$i];
    
    			if ($edit->is_conflict())
    			{
    				$conflicts[] = array($edit->final1, $edit->final2);
    			}
    		}
    
    		return $conflicts;
    	}
    
    	/**
    	* @access private
    	*/
    	function _diff3(&$edits1, &$edits2)
    	{
    		$edits = array();
    		$bb = new diff3_block_builder();
    
    		$e1 = current($edits1);
    		$e2 = current($edits2);
    
    		while ($e1 || $e2)
    		{
    			if ($e1 && $e2 && is_a($e1, 'diff_op_copy') && is_a($e2, 'diff_op_copy'))
    			{
    				// We have copy blocks from both diffs. This is the (only) time we want to emit a diff3 copy block.
    				// Flush current diff3 diff block, if any.
    				if ($edit = $bb->finish())
    				{
    					$edits[] = $edit;
    				}
    
    				$ncopy = min($e1->norig(), $e2->norig());
    				$edits[] = new diff3_op_copy(array_slice($e1->orig, 0, $ncopy));
    
    				if ($e1->norig() > $ncopy)
    				{
    					array_splice($e1->orig, 0, $ncopy);
    					array_splice($e1->final, 0, $ncopy);
    				}
    				else
    				{
    					$e1 = next($edits1);
    				}
    
    				if ($e2->norig() > $ncopy)
    				{
    					array_splice($e2->orig, 0, $ncopy);
    					array_splice($e2->final, 0, $ncopy);
    				}
    				else
    				{
    					$e2 = next($edits2);
    				}
    			}
    			else
    			{
    				if ($e1 && $e2)
    				{
    					if ($e1->orig && $e2->orig)
    					{
    						$norig = min($e1->norig(), $e2->norig());
    						$orig = array_splice($e1->orig, 0, $norig);
    						array_splice($e2->orig, 0, $norig);
    						$bb->input($orig);
    					}
    					else
    					{
    						$norig = 0;
    					}
    
    					if (is_a($e1, 'diff_op_copy'))
    					{
    						$bb->out1(array_splice($e1->final, 0, $norig));
    					}
    
    					if (is_a($e2, 'diff_op_copy'))
    					{
    						$bb->out2(array_splice($e2->final, 0, $norig));
    					}
    				}
    
    				if ($e1 && ! $e1->orig)
    				{
    					$bb->out1($e1->final);
    					$e1 = next($edits1);
    				}
    
    				if ($e2 && ! $e2->orig)
    				{
    					$bb->out2($e2->final);
    					$e2 = next($edits2);
    				}
    			}
    		}
    
    		if ($edit = $bb->finish())
    		{
    			$edits[] = $edit;
    		}
    
    		return $edits;
    	}
    }
    
    /**
    * @package diff
    * @author  Geoffrey T. Dairiki <dairiki@dairiki.org>
    *
    * @access private
    */
    class diff3_op
    {
    	function __construct($orig = false, $final1 = false, $final2 = false)
    	{
    		$this->orig = $orig ? $orig : array();
    		$this->final1 = $final1 ? $final1 : array();
    		$this->final2 = $final2 ? $final2 : array();
    	}
    
    	function merged()
    	{
    		if (!isset($this->_merged))
    		{
    			// Prepare the arrays before we compare them. ;)
    			$this->solve_prepare();
    
    			if ($this->final1 === $this->final2)
    			{
    				$this->_merged = &$this->final1;
    			}
    			else if ($this->final1 === $this->orig)
    			{
    				$this->_merged = &$this->final2;
    			}
    			else if ($this->final2 === $this->orig)
    			{
    				$this->_merged = &$this->final1;
    			}
    			else
    			{
    				// The following tries to aggressively solve conflicts...
    				$this->_merged = false;
    				$this->solve_conflict();
    			}
    		}
    
    		return $this->_merged;
    	}
    
    	function is_conflict()
    	{
    		return ($this->merged() === false) ? true : false;
    	}
    
    	/**
    	* Function to prepare the arrays for comparing - we want to skip over newline changes
    	* @author acydburn
    	*/
    	function solve_prepare()
    	{
    		// We can simplify one case where the array is usually supposed to be empty...
    		if (count($this->orig) == 1 && trim($this->orig[0]) === '') $this->orig = array();
    		if (count($this->final1) == 1 && trim($this->final1[0]) === '') $this->final1 = array();
    		if (count($this->final2) == 1 && trim($this->final2[0]) === '') $this->final2 = array();
    
    		// Now we only can have the case where the only difference between arrays are newlines, so compare all cases
    
    		// First, some strings we can compare...
    		$orig = $final1 = $final2 = '';
    
    		foreach ($this->orig as $null => $line) $orig .= trim($line);
    		foreach ($this->final1 as $null => $line) $final1 .= trim($line);
    		foreach ($this->final2 as $null => $line) $final2 .= trim($line);
    
    		// final1 === final2
    		if ($final1 === $final2)
    		{
    			// We preserve the part which will be used in the merge later
    			$this->final2 = $this->final1;
    		}
    		// final1 === orig
    		else if ($final1 === $orig)
    		{
    			// Here it does not really matter what we choose, but we will use the new code
    			$this->orig = $this->final1;
    		}
    		// final2 === orig
    		else if ($final2 === $orig)
    		{
    			// Here it does not really matter too (final1 will be used), but we will use the new code
    			$this->orig = $this->final2;
    		}
    	}
    
    	/**
    	* Find code portions from $orig in $final1 and use $final2 as merged instance if provided
    	* @author acydburn
    	*/
    	function _compare_conflict_seq($orig, $final1, $final2 = false)
    	{
    		$result = array('merge_found' => false, 'merge' => array());
    
    		$_orig = &$this->$orig;
    		$_final1 = &$this->$final1;
    
    		// Ok, we basically search for $orig in $final1
    		$compare_seq = count($_orig);
    
    		// Go through the conflict code
    		for ($i = 0, $j = 0, $size = count($_final1); $i < $size; $i++, $j = $i)
    		{
    			$line = $_final1[$i];
    			$skip = 0;
    
    			for ($x = 0; $x < $compare_seq; $x++)
    			{
    				// Try to skip all matching lines
    				if (trim($line) === trim($_orig[$x]))
    				{
    					$line = (++$j < $size) ? $_final1[$j] : $line;
    					$skip++;
    				}
    			}
    
    			if ($skip === $compare_seq)
    			{
    				$result['merge_found'] = true;
    
    				if ($final2 !== false)
    				{
    					$result['merge'] = array_merge($result['merge'], $this->$final2);
    				}
    				$i += ($skip - 1);
    			}
    			else if ($final2 !== false)
    			{
    				$result['merge'][] = $line;
    			}
    		}
    
    		return $result;
    	}
    
    	/**
    	* Tries to solve conflicts aggressively based on typical "assumptions"
    	* @author acydburn
    	*/
    	function solve_conflict()
    	{
    		$this->_merged = false;
    
    		// CASE ONE: orig changed into final2, but modified/unknown code in final1.
    		// IF orig is found "as is" in final1 we replace the code directly in final1 and populate this as final2/merge
    		if (count($this->orig) && count($this->final2))
    		{
    			$result = $this->_compare_conflict_seq('orig', 'final1', 'final2');
    
    			if ($result['merge_found'])
    			{
    				$this->final2 = $result['merge'];
    				$this->_merged = &$this->final2;
    				return;
    			}
    
    			$result = $this->_compare_conflict_seq('final2', 'final1');
    
    			if ($result['merge_found'])
    			{
    				$this->_merged = &$this->final1;
    				return;
    			}
    
    			// Try to solve $Id$ issues. ;)
    			if (count($this->orig) == 1 && count($this->final1) == 1 && count($this->final2) == 1)
    			{
    				$match = '#^' . preg_quote('* @version $Id: ', '#') . '[a-z\._\- ]+[0-9]+ [0-9]{4}-[0-9]{2}-[0-9]{2} [0-9\:Z]+ [a-z0-9_\- ]+\$$#';
    
    				if (preg_match($match, $this->orig[0]) && preg_match($match, $this->final1[0]) && preg_match($match, $this->final2[0]))
    				{
    					$this->_merged = &$this->final2;
    					return;
    				}
    			}
    
    			$second_run = false;
    
    			// Try to solve issues where the only reason why the above did not work is a newline being removed in the final1 code but exist in the orig/final2 code
    			if (trim($this->orig[0]) === '' && trim($this->final2[0]) === '')
    			{
    				unset($this->orig[0], $this->final2[0]);
    				$this->orig = array_values($this->orig);
    				$this->final2 = array_values($this->final2);
    
    				$second_run = true;
    			}
    
    			// The same is true for a line at the end. ;)
    			if (count($this->orig) && count($this->final2) && count($this->orig) === count($this->final2) && trim($this->orig[count($this->orig)-1]) === '' && trim($this->final2[count($this->final2)-1]) === '')
    			{
    				unset($this->orig[count($this->orig)-1], $this->final2[count($this->final2)-1]);
    				$this->orig = array_values($this->orig);
    				$this->final2 = array_values($this->final2);
    
    				$second_run = true;
    			}
    
    			if ($second_run)
    			{
    				$result = $this->_compare_conflict_seq('orig', 'final1', 'final2');
    
    				if ($result['merge_found'])
    				{
    					$this->final2 = $result['merge'];
    					$this->_merged = &$this->final2;
    					return;
    				}
    
    				$result = $this->_compare_conflict_seq('final2', 'final1');
    
    				if ($result['merge_found'])
    				{
    					$this->_merged = &$this->final1;
    					return;
    				}
    			}
    
    			return;
    		}
    
    		// CASE TWO: Added lines from orig to final2 but final1 had added lines too. Just merge them.
    		if (!count($this->orig) && $this->final1 !== $this->final2 && count($this->final1) && count($this->final2))
    		{
    			$result = $this->_compare_conflict_seq('final2', 'final1');
    
    			if ($result['merge_found'])
    			{
    				$this->final2 = $this->final1;
    				$this->_merged = &$this->final1;
    			}
    			else
    			{
    				$result = $this->_compare_conflict_seq('final1', 'final2');
    
    				if (!$result['merge_found'])
    				{
    					$this->final2 = array_merge($this->final1, $this->final2);
    					$this->_merged = &$this->final2;
    				}
    				else
    				{
    					$this->final2 = $this->final1;
    					$this->_merged = &$this->final1;
    				}
    			}
    
    			return;
    		}
    
    		// CASE THREE: Removed lines (orig has the to-remove line(s), but final1 has additional lines which does not need to be removed). Just remove orig from final1 and then use final1 as final2/merge
    		if (!count($this->final2) && count($this->orig) && count($this->final1) && $this->orig !== $this->final1)
    		{
    			$result = $this->_compare_conflict_seq('orig', 'final1');
    
    			if (!$result['merge_found'])
    			{
    				return;
    			}
    
    			// First of all, try to find the code in orig in final1. ;)
    			$compare_seq = count($this->orig);
    			$begin = $end = -1;
    			$j = 0;
    
    			for ($i = 0, $size = count($this->final1); $i < $size; $i++)
    			{
    				$line = $this->final1[$i];
    
    				if (trim($line) === trim($this->orig[$j]))
    				{
    					// Mark begin
    					if ($begin === -1)
    					{
    						$begin = $i;
    					}
    
    					// End is always $i, the last found line
    					$end = $i;
    
    					if (isset($this->orig[$j+1]))
    					{
    						$j++;
    					}
    				}
    			}
    
    			if ($begin !== -1 && $begin + ($compare_seq - 1) == $end)
    			{
    				foreach ($this->final1 as $i => $line)
    				{
    					if ($i < $begin || $i > $end)
    					{
    						$merged[] = $line;
    					}
    				}
    
    				$this->final2 = $merged;
    				$this->_merged = &$this->final2;
    			}
    
    			return;
    		}
    
    		return;
    	}
    }
    
    /**
    * @package diff
    * @author  Geoffrey T. Dairiki <dairiki@dairiki.org>
    *
    * @access private
    */
    class diff3_op_copy extends diff3_op
    {
    	function __construct($lines = false)
    	{
    		$this->orig = $lines ? $lines : array();
    		$this->final1 = &$this->orig;
    		$this->final2 = &$this->orig;
    	}
    
    	function merged()
    	{
    		return $this->orig;
    	}
    
    	function is_conflict()
    	{
    		return false;
    	}
    }
    
    /**
    * @package diff
    * @author  Geoffrey T. Dairiki <dairiki@dairiki.org>
    *
    * @access private
    */
    class diff3_block_builder
    {
    	function __construct()
    	{
    		$this->_init();
    	}
    
    	function input($lines)
    	{
    		if ($lines)
    		{
    			$this->_append($this->orig, $lines);
    		}
    	}
    
    	function out1($lines)
    	{
    		if ($lines)
    		{
    			$this->_append($this->final1, $lines);
    		}
    	}
    
    	function out2($lines)
    	{
    		if ($lines)
    		{
    			$this->_append($this->final2, $lines);
    		}
    	}
    
    	function is_empty()
    	{
    		return !$this->orig && !$this->final1 && !$this->final2;
    	}
    
    	function finish()
    	{
    		if ($this->is_empty())
    		{
    			return false;
    		}
    		else
    		{
    			$edit = new diff3_op($this->orig, $this->final1, $this->final2);
    			$this->_init();
    			return $edit;
    		}
    	}
    
    	function _init()
    	{
    		$this->orig = $this->final1 = $this->final2 = array();
    	}
    
    	function _append(&$array, $lines)
    	{
    		array_splice($array, count($array), 0, $lines);
    	}
    }