Subversion Repositories Applications.projet

<?php

/*

diff.php

Copyright (C) 1992 Free Software Foundation, Inc. Francois Pinard <pinard@iro.umontreal.ca>.

Copyright (C) 2000, 2001 Geoffrey T. Dairiki <dairiki@dairiki.org>

Copyright 2002,2003,2004  David DELON

Copyright 2002  Patrick PAUL

Copyright 2003  Eric FELDSTEIN

This program is free software; you can redistribute it and/or modify

it under the terms of the GNU General Public License as published by

the Free Software Foundation; either version 2 of the License, or

(at your option) any later version.

This program is distributed in the hope that it will be useful,

but WITHOUT ANY WARRANTY; without even the implied warranty of

MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

GNU General Public License for more details.

You should have received a copy of the GNU General Public License

along with this program; if not, write to the Free Software

Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

original diff.php

Copyright (c) 2002, Hendrik Mans <hendrik@mans.de>

All rights reserved.

Redistribution and use in source and binary forms, with or without

modification, are permitted provided that the following conditions

are met:

1. Redistributions of source code must retain the above copyright

notice, this list of conditions and the following disclaimer.

2. Redistributions in binary form must reproduce the above copyright

notice, this list of conditions and the following disclaimer in the

documentation and/or other materials provided with the distribution.

3. The name of the author may not be used to endorse or promote products

derived from this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR

IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES

OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.

IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,

INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT

NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,

DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY

THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT

(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF

THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

*/

//vérification de sécurité

if (!eregi("wakka.php", $_SERVER['PHP_SELF'])) {

    die ("accès direct interdit");

}

echo $this->Header();

?>

<div class="page">

<?php

if ($this->HasAccess("read"))

{

// If asked, call original diff

	if ($_REQUEST["fastdiff"]) {

		/* NOTE: This is a really cheap way to do it. I think it may be more intelligent to write the two pages to temporary files and run /usr/bin/diff over them. Then again, maybe not.        */

		// load pages

		  $pageA = $this->LoadPageById($_REQUEST["a"]);

		  $pageB = $this->LoadPageById($_REQUEST["b"]);

		// prepare bodies

		  $bodyA = explode("\n", $pageA["body"]);

		  $bodyB = explode("\n", $pageB["body"]);

		  $added = array_diff($bodyA, $bodyB);

		  $deleted = array_diff($bodyB, $bodyA);

		  $output .= "<b>Comparaison de <a href=\"".$this->href("", "", "time=".urlencode($pageA["time"]))."\">".$pageA["time"]."</a> &agrave; <a href=\"".$this->href("", "", "time=".urlencode($pageB["time"]))."\">".$pageB["time"]."</a></b><br />\n";

		  if ($added)

		  {

			// remove blank lines

			$output .= "<br />\n<b>Ajouts:</b><br />\n";

			$output .= "<div class=\"additions\">".$this->Format(implode("\n", $added))."</div>";

		  }

		  if ($deleted)

		  {

			$output .= "<br />\n<b>Suppressions:</b><br />\n";

			$output .= "<div class=\"deletions\">".$this->Format(implode("\n", $deleted))."</div>";

		  }

		  if (!$added && !$deleted)

		  {

			$output .= "<br />\nPas de diff&eacute;rences.";

		  }

		  echo $output;

	}

	else {

	// load pages

		$pageA = $this->LoadPageById($_REQUEST["b"]);

		$pageB = $this->LoadPageById($_REQUEST["a"]);

		// extract text from bodies

		$textA = $pageA["body"];

		$textB = $pageB["body"];

		$sideA = new Side($textA);

		$sideB = new Side($textB);

		$bodyA='';

		$sideA->split_file_into_words($bodyA);

		$bodyB='';

		$sideB->split_file_into_words($bodyB);

		// diff on these two file

		$diff = new Diff(split("\n",$bodyA),split("\n",$bodyB));

		// format output

		$fmt = new DiffFormatter();

		$sideO = new Side($fmt->format($diff));

		$resync_left=0;

		$resync_right=0;

		$count_total_right=$sideB->getposition() ;

		$sideA->init();

		$sideB->init();

		$output='';

		  while (1) {

		      $sideO->skip_line();

		      if ($sideO->isend()) {

			  break;

		      }

		      if ($sideO->decode_directive_line()) {

			$argument=$sideO->getargument();

			$letter=$sideO->getdirective();

		      switch ($letter) {

			    case 'a':

			      $resync_left = $argument[0];

			      $resync_right = $argument[2] - 1;

			      break;

			    case 'd':

			      $resync_left = $argument[0] - 1;

			      $resync_right = $argument[2];

			      break;

			    case 'c':

			      $resync_left = $argument[0] - 1;

			      $resync_right = $argument[2] - 1;

			      break;

			    }

			    $sideA->skip_until_ordinal($resync_left);

			    $sideB->copy_until_ordinal($resync_right,$output);

	// deleted word

			    if (($letter=='d') || ($letter=='c')) {

			      $sideA->copy_whitespace($output);

			      $output .="@@";

			      $sideA->copy_word($output);

			      $sideA->copy_until_ordinal($argument[1],$output);

			      $output .="@@";

			    }

	// inserted word

			    if ($letter == 'a' || $letter == 'c') {

				$sideB->copy_whitespace($output);

				$output .="££";

				$sideB->copy_word($output);

				$sideB->copy_until_ordinal($argument[3],$output);

				$output .="££";

			    }

		  }

		}

		  $sideB->copy_until_ordinal($count_total_right,$output);

		  $sideB->copy_whitespace($output);

		  $out=$this->Format($output);

		  echo $out;

	}

}

else{

	echo "<i>Vous n'&ecirc;tes pas autoris&eacute; &agrave; lire cette page.</i>" ;

}

	// Side : a string for wdiff

	class Side {

	    var $position;

	    var $cursor;

	    var $content;

	    var $character;

	    var $directive;

	    var $argument;

	    var $length;

	    function Side($content) {

	       $this->content=$content;

	       $this->position=0;

	       $this->cursor=0;

	       $this->directive='';

	       $this->argument=array();

	       $this->length=strlen($this->content);

	       $this->character=substr($this->content,0,1);

	    }

	    function getposition() {

	       return $this->position;

	    }

	    function getcharacter() {

	       return $this->character;

	    }

	    function getdirective() {

	       return $this->directive;

	    }

	    function getargument() {

	       return $this->argument;

	    }

	    function nextchar() {

	       $this->cursor++;

	       $this->character=substr($this->content,$this->cursor,1);

	    }

	    function copy_until_ordinal($ordinal,&$out)  {

	       while ($this->position < $ordinal) {

		  $this->copy_whitespace($out);

		  $this->copy_word($out);

	       }

	    }

	    function skip_until_ordinal($ordinal) {

	       while ($this->position < $ordinal) {

		  $this->skip_whitespace();

		  $this->skip_word();

	       }

	    }

	    function split_file_into_words (&$out) {

	       while (!$this->isend()) {

		 $this->skip_whitespace();

		 if ($this->isend()) {

		   break;

		 }

		 $this->copy_word($out);

		 $out .="\n";

	       }

	    }

	    function init() {

	       $this->position=0;

	       $this->cursor=0;

	       $this->directive='';

	       $this->argument=array();

	       $this->character=substr($this->content,0,1);

	    }

	    function isspace($char) {

	       if (ereg('[[:space:]]',$char)) {

		  return true;

	       }

	       else {

		  return false;

	       }

	    }

	    function isdigit($char) {

	       if (ereg('[[:digit:]]',$char)) {

		  return true;

	       }

	       else {

		  return false;

	       }

	    }

	    function isend() {

	       if (($this->cursor)>=($this->length)) {

		  return true;

	       }

	       else {

		  return false;

	       }

	    }

	    function copy_whitespace(&$out)  {

		 while (!$this->isend() && $this->isspace($this->character)) {

		    $out .=$this->character;

		    $this->nextchar();

		 }

	    }

	    function skip_whitespace()  {

		 while (!$this->isend() && $this->isspace($this->character)) {

		    $this->nextchar();

		 }

	    }

	    function skip_line()  {

	      while (!$this->isend() && !$this->isdigit($this->character)) {

		  while (!$this->isend() && $this->character!="\n")

		  $this->nextchar();

		  if($this->character=="\n")

		      $this->nextchar();

	       }

	     }

	     function copy_word(&$out) {

		 while (!$this->isend() && !($this->isspace($this->character))) {

		    $out.=$this->character;

		    $this->nextchar();

		 }

		 $this->position++;

	     }

	     function skip_word() {

		 while (!$this->isend() && !($this->isspace($this->character))) {

		    $this->nextchar();

		 }

		 $this->position++;

	     }

	 function decode_directive_line() {

	  $value=0;

	  $state=0;

	  $error=0;

	  while (!$error && $state < 4) {

	      if ($this->isdigit($this->character)) {

		  $value = 0;

		  while($this->isdigit($this->character)) {

		      $value = 10 * $value + $this->character - '0';

		      $this->nextchar();

		  }

	      }

	      else if ($state != 1 && $state != 3)

	      $error = 1;

	      /* Assign the proper value.  */

	      $this->argument[$state] = $value;

	      /* Skip the following character.  */

	      switch ($state) {

		case 0:

		case 2:

		  if ($this->character == ',')

		     $this->nextchar();

		  break;

		case 1:

		  if ($this->character == 'a' || $this->character == 'd' || $this->character == 'c') {

		      $this->directive = $this->character;

		      $this->nextchar();

		    }

		  else

		    $error = 1;

		  break;

		  case 3:

		  if ($this->character != "\n")

		    $error = 1;

		    break;

		  }

		 $state++;

	      }

	  /* Complete reading of the line and return success value.  */

	  while ((!$this->isend()) && ($this->character != "\n")) {

	      $this->nextchar();

	  }

	  if ($this->character == "\n")

	      $this->nextchar();

	  return !$error;

	}

	}

	// difflib

	//

	// A PHP diff engine for phpwiki.

	//

	// Copyright (C) 2000, 2001 Geoffrey T. Dairiki <dairiki@dairiki.org>

	// You may copy this code freely under the conditions of the GPL.

	//

	// PHP3 does not have assert()

	define('USE_ASSERTS', function_exists('assert'));

	class _DiffOp {

	    var $type;

	    var $orig;

	    var $final;

	    function norig() {

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

	    }

	    function nfinal() {

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

	    }

	}

	class _DiffOp_Copy extends _DiffOp {

	    var $type = 'copy';

	    function _DiffOp_Copy ($orig, $final = false) {

		if (!is_array($final))

		    $final = $orig;

		$this->orig = $orig;

		$this->final = $final;

	    }

	}

	class _DiffOp_Delete extends _DiffOp {

	    var $type = 'delete';

	    function _DiffOp_Delete ($lines) {

		$this->orig = $lines;

		$this->final = false;

	    }

	}

	class _DiffOp_Add extends _DiffOp {

	    var $type = 'add';

	    function _DiffOp_Add ($lines) {

		$this->final = $lines;

		$this->orig = false;

	    }

	}

	class _DiffOp_Change extends _DiffOp {

	    var $type = 'change';

	    function _DiffOp_Change ($orig, $final) {

		$this->orig = $orig;

		$this->final = $final;

	    }

	}

	/**

	 * Class used internally by Diff to actually compute the diffs.

	 *

	 * The algorithm used here is mostly lifted from the perl module

	 * Algorithm::Diff (version 1.06) by Ned Konz, which is available at:

	 *   http://www.perl.com/CPAN/authors/id/N/NE/NEDKONZ/Algorithm-Diff-1.06.zip

	 *

	 * More ideas are taken from:

	 *   http://www.ics.uci.edu/~eppstein/161/960229.html

	 *

	 * Some ideas are (and a bit of code) are from from analyze.c, from GNU

	 * diffutils-2.7, which can be found at:

	 *   ftp://gnudist.gnu.org/pub/gnu/diffutils/diffutils-2.7.tar.gz

	 *

	 * Finally, some ideas (subdivision by NCHUNKS > 2, and some optimizations)

	 * are my own.

	 *

	 * @author Geoffrey T. Dairiki

	 * @access private

	 */

	class _DiffEngine

	{

	    function diff ($from_lines, $to_lines) {

		$n_from = sizeof($from_lines);

		$n_to = sizeof($to_lines);

		$this->xchanged = $this->ychanged = array();

		$this->xv = $this->yv = array();

		$this->xind = $this->yind = array();

		unset($this->seq);

		unset($this->in_seq);

		unset($this->lcs);

		// Skip leading common lines.

		for ($skip = 0; $skip < $n_from && $skip < $n_to; $skip++) {

		    if ($from_lines[$skip] != $to_lines[$skip])

			break;

		    $this->xchanged[$skip] = $this->ychanged[$skip] = false;

		}

		// Skip trailing common lines.

		$xi = $n_from; $yi = $n_to;

		for ($endskip = 0; --$xi > $skip && --$yi > $skip; $endskip++) {

		    if ($from_lines[$xi] != $to_lines[$yi])

			break;

		    $this->xchanged[$xi] = $this->ychanged[$yi] = false;

		}

		// Ignore lines which do not exist in both files.

		for ($xi = $skip; $xi < $n_from - $endskip; $xi++)

		    $xhash[$from_lines[$xi]] = 1;

		for ($yi = $skip; $yi < $n_to - $endskip; $yi++) {

		    $line = $to_lines[$yi];

		    if ( ($this->ychanged[$yi] = empty($xhash[$line])) )

			continue;

		    $yhash[$line] = 1;

		    $this->yv[] = $line;

		    $this->yind[] = $yi;

		}

		for ($xi = $skip; $xi < $n_from - $endskip; $xi++) {

		    $line = $from_lines[$xi];

		    if ( ($this->xchanged[$xi] = empty($yhash[$line])) )

			continue;

		    $this->xv[] = $line;

		    $this->xind[] = $xi;

		}

		// Find the LCS.

		$this->_compareseq(0, sizeof($this->xv), 0, sizeof($this->yv));

		// Merge edits when possible

		$this->_shift_boundaries($from_lines, $this->xchanged, $this->ychanged);

		$this->_shift_boundaries($to_lines, $this->ychanged, $this->xchanged);

		// Compute the edit operations.

		$edits = array();

		$xi = $yi = 0;

		while ($xi < $n_from || $yi < $n_to) {

		    USE_ASSERTS && assert($yi < $n_to || $this->xchanged[$xi]);

		    USE_ASSERTS && assert($xi < $n_from || $this->ychanged[$yi]);

		    // Skip matching "snake".

		    $copy = array();

		    while ( $xi < $n_from && $yi < $n_to

			    && !$this->xchanged[$xi] && !$this->ychanged[$yi]) {

			$copy[] = $from_lines[$xi++];

			++$yi;

		    }

		    if ($copy)

			$edits[] = new _DiffOp_Copy($copy);

		    // Find deletes & adds.

		    $delete = array();

		    while ($xi < $n_from && $this->xchanged[$xi])

			$delete[] = $from_lines[$xi++];

		    $add = array();

		    while ($yi < $n_to && $this->ychanged[$yi])

			$add[] = $to_lines[$yi++];

		    if ($delete && $add)

			$edits[] = new _DiffOp_Change($delete, $add);

		    elseif ($delete)

			$edits[] = new _DiffOp_Delete($delete);

		    elseif ($add)

			$edits[] = new _DiffOp_Add($add);

		}

		return $edits;

	    }

	    /* Divide the Largest Common Subsequence (LCS) of the sequences

	     * [XOFF, XLIM) and [YOFF, YLIM) into NCHUNKS approximately equally

	     * sized segments.

	     *

	     * Returns (LCS, PTS).  LCS is the length of the LCS. PTS is an

	     * array of NCHUNKS+1 (X, Y) indexes giving the diving points between

	     * sub sequences.  The first sub-sequence is contained in [X0, X1),

	     * [Y0, Y1), the second in [X1, X2), [Y1, Y2) and so on.  Note

	     * that (X0, Y0) == (XOFF, YOFF) and

	     * (X[NCHUNKS], Y[NCHUNKS]) == (XLIM, YLIM).

	     *

	     * This function assumes that the first lines of the specified portions

	     * of the two files do not match, and likewise that the last lines do not

	     * match.  The caller must trim matching lines from the beginning and end

	     * of the portions it is going to specify.

	     */

	    function _diag ($xoff, $xlim, $yoff, $ylim, $nchunks) {

		$flip = false;

		if ($xlim - $xoff > $ylim - $yoff) {

		    // Things seems faster (I'm not sure I understand why)

		    // when the shortest sequence in X.

		    $flip = true;

		    list ($xoff, $xlim, $yoff, $ylim)

			= array( $yoff, $ylim, $xoff, $xlim);

		}

		if ($flip)

		    for ($i = $ylim - 1; $i >= $yoff; $i--)

			$ymatches[$this->xv[$i]][] = $i;

		else

		    for ($i = $ylim - 1; $i >= $yoff; $i--)

			$ymatches[$this->yv[$i]][] = $i;

		$this->lcs = 0;

		$this->seq[0]= $yoff - 1;

		$this->in_seq = array();

		$ymids[0] = array();

		$numer = $xlim - $xoff + $nchunks - 1;

		$x = $xoff;

		for ($chunk = 0; $chunk < $nchunks; $chunk++) {

		    if ($chunk > 0)

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

			    $ymids[$i][$chunk-1] = $this->seq[$i];

		    $x1 = $xoff + (int)(($numer + ($xlim-$xoff)*$chunk) / $nchunks);

		    for ( ; $x < $x1; $x++) {

			$line = $flip ? $this->yv[$x] : $this->xv[$x];

			if (empty($ymatches[$line]))

			    continue;

			$matches = $ymatches[$line];

			reset($matches);

			while (list ($junk, $y) = each($matches))

			    if (empty($this->in_seq[$y])) {

				$k = $this->_lcs_pos($y);

				USE_ASSERTS && assert($k > 0);

				$ymids[$k] = $ymids[$k-1];

				break;

			    }

			while (list ($junk, $y) = each($matches)) {

			    if ($y > $this->seq[$k-1]) {

				USE_ASSERTS && assert($y < $this->seq[$k]);

				// Optimization: this is a common case:

				//  next match is just replacing previous match.

				$this->in_seq[$this->seq[$k]] = false;

				$this->seq[$k] = $y;

				$this->in_seq[$y] = 1;

			    }

			    else if (empty($this->in_seq[$y])) {

				$k = $this->_lcs_pos($y);

				USE_ASSERTS && assert($k > 0);

				$ymids[$k] = $ymids[$k-1];

			    }

			}

		    }

		}

		$seps[] = $flip ? array($yoff, $xoff) : array($xoff, $yoff);

		$ymid = $ymids[$this->lcs];

		for ($n = 0; $n < $nchunks - 1; $n++) {

		    $x1 = $xoff + (int)(($numer + ($xlim - $xoff) * $n) / $nchunks);

		    $y1 = $ymid[$n] + 1;

		    $seps[] = $flip ? array($y1, $x1) : array($x1, $y1);

		}

		$seps[] = $flip ? array($ylim, $xlim) : array($xlim, $ylim);

		return array($this->lcs, $seps);

	    }

	    function _lcs_pos ($ypos) {

		$end = $this->lcs;

		if ($end == 0 || $ypos > $this->seq[$end]) {

		    $this->seq[++$this->lcs] = $ypos;

		    $this->in_seq[$ypos] = 1;

		    return $this->lcs;

		}

		$beg = 1;

		while ($beg < $end) {

		    $mid = (int)(($beg + $end) / 2);

		    if ( $ypos > $this->seq[$mid] )

			$beg = $mid + 1;

		    else

			$end = $mid;

		}

		USE_ASSERTS && assert($ypos != $this->seq[$end]);

		$this->in_seq[$this->seq[$end]] = false;

		$this->seq[$end] = $ypos;

		$this->in_seq[$ypos] = 1;

		return $end;

	    }

	    /* Find LCS of two sequences.

	     *

	     * The results are recorded in the vectors $this->{x,y}changed[], by

	     * storing a 1 in the element for each line that is an insertion

	     * or deletion (ie. is not in the LCS).

	     *

	     * The subsequence of file 0 is [XOFF, XLIM) and likewise for file 1.

	     *

	     * Note that XLIM, YLIM are exclusive bounds.

	     * All line numbers are origin-0 and discarded lines are not counted.

	     */

	    function _compareseq ($xoff, $xlim, $yoff, $ylim) {

		// Slide down the bottom initial diagonal.

		while ($xoff < $xlim && $yoff < $ylim

		       && $this->xv[$xoff] == $this->yv[$yoff]) {

		    ++$xoff;

		    ++$yoff;

		}

		// Slide up the top initial diagonal.

		while ($xlim > $xoff && $ylim > $yoff

		       && $this->xv[$xlim - 1] == $this->yv[$ylim - 1]) {

		    --$xlim;

		    --$ylim;

		}

		if ($xoff == $xlim || $yoff == $ylim)

		    $lcs = 0;

		else {

		    // This is ad hoc but seems to work well.

		    //$nchunks = sqrt(min($xlim - $xoff, $ylim - $yoff) / 2.5);

		    //$nchunks = max(2,min(8,(int)$nchunks));

		    $nchunks = min(7, $xlim - $xoff, $ylim - $yoff) + 1;

		    list ($lcs, $seps)

			= $this->_diag($xoff,$xlim,$yoff, $ylim,$nchunks);

		}

		if ($lcs == 0) {

		    // X and Y sequences have no common subsequence:

		    // mark all changed.

		    while ($yoff < $ylim)

			$this->ychanged[$this->yind[$yoff++]] = 1;

		    while ($xoff < $xlim)

			$this->xchanged[$this->xind[$xoff++]] = 1;

		}

		else {

		    // Use the partitions to split this problem into subproblems.

		    reset($seps);

		    $pt1 = $seps[0];

		    while ($pt2 = next($seps)) {

			$this->_compareseq ($pt1[0], $pt2[0], $pt1[1], $pt2[1]);

			$pt1 = $pt2;

		    }

		}

	    }

	    /* Adjust inserts/deletes of identical lines to join changes

	     * as much as possible.

	     *

	     * We do something when a run of changed lines include a

	     * line at one end and has an excluded, identical line at the other.

	     * We are free to choose which identical line is included.

	     * `compareseq' usually chooses the one at the beginning,

	     * but usually it is cleaner to consider the following identical line

	     * to be the "change".

	     *

	     * This is extracted verbatim from analyze.c (GNU diffutils-2.7).

	     */

	    function _shift_boundaries ($lines, &$changed, $other_changed) {

		$i = 0;

		$j = 0;

		USE_ASSERTS && assert('sizeof($lines) == sizeof($changed)');

		$len = sizeof($lines);

		$other_len = sizeof($other_changed);

		while (1) {

		    /*

		     * Scan forwards to find beginning of another run of changes.

		     * Also keep track of the corresponding point in the other file.

		     *

		     * Throughout this code, $i and $j are adjusted together so that

		     * the first $i elements of $changed and the first $j elements

		     * of $other_changed both contain the same number of zeros

		     * (unchanged lines).

		     * Furthermore, $j is always kept so that $j == $other_len or

		     * $other_changed[$j] == false.

		     */

		    while ($j < $other_len && $other_changed[$j])

			$j++;

		    while ($i < $len && ! $changed[$i]) {

			USE_ASSERTS && assert('$j < $other_len && ! $other_changed[$j]');

			$i++; $j++;

			while ($j < $other_len && $other_changed[$j])

			    $j++;

		    }

		    if ($i == $len)

			break;

		    $start = $i;

		    // Find the end of this run of changes.

		    while (++$i < $len && $changed[$i])

			continue;

		    do {

			/*

			 * Record the length of this run of changes, so that

			 * we can later determine whether the run has grown.

			 */

			$runlength = $i - $start;

			/*

			 * Move the changed region back, so long as the

			 * previous unchanged line matches the last changed one.

			 * This merges with previous changed regions.

			 */

			while ($start > 0 && $lines[$start - 1] == $lines[$i - 1]) {

			    $changed[--$start] = 1;

			    $changed[--$i] = false;

			    while ($start > 0 && $changed[$start - 1])

				$start--;

			    USE_ASSERTS && assert('$j > 0');

			    while ($other_changed[--$j])

				continue;

			    USE_ASSERTS && assert('$j >= 0 && !$other_changed[$j]');

			}

			/*

			 * Set CORRESPONDING to the end of the changed run, at the last

			 * point where it corresponds to a changed run in the other file.

			 * CORRESPONDING == LEN means no such point has been found.

			 */

			$corresponding = $j < $other_len ? $i : $len;

			/*

			 * Move the changed region forward, so long as the

			 * first changed line matches the following unchanged one.

			 * This merges with following changed regions.

			 * Do this second, so that if there are no merges,

			 * the changed region is moved forward as far as possible.

			 */

			while ($i < $len && $lines[$start] == $lines[$i]) {

			    $changed[$start++] = false;

			    $changed[$i++] = 1;

			    while ($i < $len && $changed[$i])

				$i++;

			    USE_ASSERTS && assert('$j < $other_len && ! $other_changed[$j]');

			    $j++;

			    if ($j < $other_len && $other_changed[$j]) {

				$corresponding = $i;

				while ($j < $other_len && $other_changed[$j])

				    $j++;

			    }

			}

		    } while ($runlength != $i - $start);

		    /*

		     * If possible, move the fully-merged run of changes

		     * back to a corresponding run in the other file.

		     */

		    while ($corresponding < $i) {

			$changed[--$start] = 1;

			$changed[--$i] = 0;

			USE_ASSERTS && assert('$j > 0');

			while ($other_changed[--$j])

			    continue;

			USE_ASSERTS && assert('$j >= 0 && !$other_changed[$j]');

		    }

		}

	    }

	}

	/**

	 * Class representing a 'diff' between two sequences of strings.

	 */

	class Diff

	{

	    var $edits;

	    /**

	     * Constructor.

	     * Computes diff between sequences of strings.

	     *

	     * @param $from_lines array An array of strings.

	     *        (Typically these are lines from a file.)

	     * @param $to_lines array An array of strings.

	     */

	    function Diff($from_lines, $to_lines) {

		$eng = new _DiffEngine;

		$this->edits = $eng->diff($from_lines, $to_lines);

	    }

	}

	/**

	 * A class to format Diffs

	 *

	 * This class formats the diff in classic diff format.

	 * It is intended that this class be customized via inheritance,

	 * to obtain fancier outputs.

	 */

	class DiffFormatter

	{

	    /**

	     * Format a diff.

	     *

	     * @param $diff object A Diff object.

	     * @return string The formatted output.

	     */

	    function format($diff) {

		$xi = $yi = 1;

		$block = false;

		$context = array();

		$this->_start_diff();

		foreach ($diff->edits as $edit) {

		    if ($edit->type == 'copy') {

			if (is_array($block)) {

			    if (sizeof($edit->orig) <= 0) {

				$block[] = $edit;

			    }

			    else{

				$this->_block($x0, + $xi - $x0,

					      $y0, + $yi - $y0,

					      $block);

				$block = false;

			    }

			}

		    }

		    else {

			if (! is_array($block)) {

			    $x0 = $xi;

			    $y0 = $yi;

			    $block = array();

			}

			$block[] = $edit;

		    }

		    if ($edit->orig)

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

		    if ($edit->final)

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

		}

		if (is_array($block))

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

				  $y0, $yi - $y0,

				  $block);

		return $this->_end_diff();

	    }

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

		$this->_start_block($this->_block_header($xbeg, $xlen, $ybeg, $ylen));

	    }

	    function _start_diff() {

		ob_start();

	    }

	    function _end_diff() {

		$val = ob_get_contents();

		ob_end_clean();

		return $val;

	    }

	    function _block_header($xbeg, $xlen, $ybeg, $ylen) {

		if ($xlen > 1)

		    $xbeg .= "," . ($xbeg + $xlen - 1);

		if ($ylen > 1)

		    $ybeg .= "," . ($ybeg + $ylen - 1);

		return $xbeg . ($xlen ? ($ylen ? 'c' : 'd') : 'a') . $ybeg;

	    }

	    function _start_block($header) {

		echo $header."\n";

	    }

	}

?>

</div>

<?php echo $this->Footer(); ?>