/**

*

* @package diff

* @version $Id: diff.php 8765 2008-08-16 22:18:25Z aptx $

* @copyright (c) 2006 phpBB Group

* @license http://opensource.org/licenses/gpl-license.php GNU Public License

*

*/

/**

* @ignore

*/

if (!defined('IN_PHPBB'))

{

	exit;

}

/**

* Code from pear.php.net, Text_Diff-1.0.0 package

* http://pear.php.net/package/Text_Diff/

*

* Modified by phpBB Group 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_lines  An array of strings. Typically these are lines from a file.

	* @param array $to_lines    An array of strings.

	*/

	function diff(&$from_content, &$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;

	}

	/**

	* Computes a reversed diff.

	*

	* Example:

	* 

	* $diff = new diff($lines1, $lines2);

	* $rev = $diff->reverse();

	* 

	*

	* @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();

		foreach ($this->_edits as $edit)

		{

			$rev->_edits[] = $edit->reverse();

		}

		return $rev;

	}

	/**

	* Checks for an empty diff.

	*

	* @return boolean  True if two sequences were identical.

	*/

	function is_empty()

	{

		foreach ($this->_edits as $edit)

		{

			if (!is_a($edit, 'diff_op_copy'))

			{

				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;

		foreach ($this->_edits as $edit)

		{

			if (is_a($edit, 'diff_op_copy'))

			{

				$lcs += sizeof($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();

		foreach ($this->_edits as $edit)

		{

			if ($edit->orig)

			{

				array_splice($lines, sizeof($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();

		foreach ($this->_edits as $edit)

		{

			if ($edit->final)

			{

				array_splice($lines, sizeof($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;

		foreach ($this->_edits as $edit)

		{

			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 mapped_diff(&$from_lines, &$to_lines, &$mapped_from_lines, &$mapped_to_lines)

	{

		if (sizeof($from_lines) != sizeof($mapped_from_lines) || sizeof($to_lines) != sizeof($mapped_to_lines))

		{

			return false;

		}

		parent::diff($mapped_from_lines, $mapped_to_lines);

		$xi = $yi = 0;

		for ($i = 0; $i < sizeof($this->_edits); $i++)

		{

			$orig = &$this->_edits[$i]->orig;

			if (is_array($orig))

			{

				$orig = array_slice($from_lines, $xi, sizeof($orig));

				$xi += sizeof($orig);

			}

			$final = &$this->_edits[$i]->final;

			if (is_array($final))

			{

				$final = array_slice($to_lines, $yi, sizeof($final));

				$yi += sizeof($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 ($this->orig) ? sizeof($this->orig) : 0;

	}

	function nfinal()

	{

		return ($this->final) ? sizeof($this->final) : 0;

	}

}

/**

* @package diff

* @author  Geoffrey T. Dairiki <dairiki@dairiki.org>

*

* @access private

*/

class diff_op_copy extends diff_op

{

	function diff_op_copy($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 diff_op_delete($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 diff_op_add($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 diff_op_change($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.

	*/

	function diff3(&$orig, &$final1, &$final2)

	{

		$diff_engine = new diff_engine();

		$diff_1 = $diff_engine->diff($orig, $final1);

		$diff_2 = $diff_engine->diff($orig, $final2);

		unset($engine);

		$this->_edits = $this->_diff3($diff_1, $diff_2);

	}

	/**

	* Return merged output

	*

	* @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

	* @param bool $get_conflicts if set to true only the number of conflicts is returned

	* @param bool $merge_new if set to true the merged output will have the new file contents on a conflicting merge

	*

	* @return mixed the merged output

	*/

	function merged_output($label1 = 'CURRENT_FILE', $label2 = 'NEW_FILE', $label_sep = 'DIFF_SEP_EXPLAIN', $get_conflicts = false, $merge_new = false)

	{

		global $user;

		if ($get_conflicts)

		{

			foreach ($this->_edits as $edit)

			{

				if ($edit->is_conflict())

				{

					$this->_conflicting_blocks++;

				}

			}

			return $this->_conflicting_blocks;

		}

		$label1 = (!empty($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();

		foreach ($this->_edits as $edit)

		{

			if ($edit->is_conflict())

			{

				if (!$merge_new)

				{

					$lines = array_merge($lines, array('<<<<<<<' . ($label1 ? ' ' . $label1 : '')), $edit->final1, array('=======' . ($label_sep ? ' ' . $label_sep : '')), $edit->final2, array('>>>>>>>' . ($label2 ? ' ' . $label2 : '')));

				}

				else

				{

					$lines = array_merge($lines, $edit->final1);

				}

				$this->_conflicting_blocks++;

			}

			else

			{

				$lines = array_merge($lines, $edit->merged());

			}

		}

		return $lines;

	}

	/**

	* Merge the output and use the new file code for conflicts

	*/

	function merged_new_output()

	{

		$lines = array();

		foreach ($this->_edits as $edit)

		{

			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();

		foreach ($this->_edits as $edit)

		{

			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();

		foreach ($this->_edits as $edit)

		{

			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 diff3_op($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))

		{

			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

			{

				$this->_merged = false;

			}

		}

		return $this->_merged;

	}

	function is_conflict()

	{

		return ($this->merged() === false) ? true : false;

	}

}

/**

* @package diff

* @author  Geoffrey T. Dairiki <dairiki@dairiki.org>

*

* @access private

*/

class diff3_op_copy extends diff3_op

{

	function diff3_op_copy($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>

*