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<?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 (is_array($orig) && count($orig) == 1 && trim($orig[0]) === '')
                {
                   
$orig = array();
                }
                if (
is_array($final) && 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);
    }
}